diff options
Diffstat (limited to 'fs/btrfs/send.c')
| -rw-r--r-- | fs/btrfs/send.c | 8136 |
1 files changed, 8136 insertions, 0 deletions
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c new file mode 100644 index 000000000..4a4d65b5e --- /dev/null +++ b/fs/btrfs/send.c @@ -0,0 +1,8136 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2012 Alexander Block. All rights reserved. + */ + +#include <linux/bsearch.h> +#include <linux/fs.h> +#include <linux/file.h> +#include <linux/sort.h> +#include <linux/mount.h> +#include <linux/xattr.h> +#include <linux/posix_acl_xattr.h> +#include <linux/radix-tree.h> +#include <linux/vmalloc.h> +#include <linux/string.h> +#include <linux/compat.h> +#include <linux/crc32c.h> +#include <linux/fsverity.h> + +#include "send.h" +#include "ctree.h" +#include "backref.h" +#include "locking.h" +#include "disk-io.h" +#include "btrfs_inode.h" +#include "transaction.h" +#include "compression.h" +#include "xattr.h" +#include "print-tree.h" + +/* + * Maximum number of references an extent can have in order for us to attempt to + * issue clone operations instead of write operations. This currently exists to + * avoid hitting limitations of the backreference walking code (taking a lot of + * time and using too much memory for extents with large number of references). + */ +#define SEND_MAX_EXTENT_REFS 64 + +/* + * A fs_path is a helper to dynamically build path names with unknown size. + * It reallocates the internal buffer on demand. + * It allows fast adding of path elements on the right side (normal path) and + * fast adding to the left side (reversed path). A reversed path can also be + * unreversed if needed. + */ +struct fs_path { + union { + struct { + char *start; + char *end; + + char *buf; + unsigned short buf_len:15; + unsigned short reversed:1; + char inline_buf[]; + }; + /* + * Average path length does not exceed 200 bytes, we'll have + * better packing in the slab and higher chance to satisfy + * a allocation later during send. + */ + char pad[256]; + }; +}; +#define FS_PATH_INLINE_SIZE \ + (sizeof(struct fs_path) - offsetof(struct fs_path, inline_buf)) + + +/* reused for each extent */ +struct clone_root { + struct btrfs_root *root; + u64 ino; + u64 offset; + + u64 found_refs; +}; + +#define SEND_CTX_MAX_NAME_CACHE_SIZE 128 +#define SEND_CTX_NAME_CACHE_CLEAN_SIZE (SEND_CTX_MAX_NAME_CACHE_SIZE * 2) + +struct send_ctx { + struct file *send_filp; + loff_t send_off; + char *send_buf; + u32 send_size; + u32 send_max_size; + /* + * Whether BTRFS_SEND_A_DATA attribute was already added to current + * command (since protocol v2, data must be the last attribute). + */ + bool put_data; + struct page **send_buf_pages; + u64 flags; /* 'flags' member of btrfs_ioctl_send_args is u64 */ + /* Protocol version compatibility requested */ + u32 proto; + + struct btrfs_root *send_root; + struct btrfs_root *parent_root; + struct clone_root *clone_roots; + int clone_roots_cnt; + + /* current state of the compare_tree call */ + struct btrfs_path *left_path; + struct btrfs_path *right_path; + struct btrfs_key *cmp_key; + + /* + * Keep track of the generation of the last transaction that was used + * for relocating a block group. This is periodically checked in order + * to detect if a relocation happened since the last check, so that we + * don't operate on stale extent buffers for nodes (level >= 1) or on + * stale disk_bytenr values of file extent items. + */ + u64 last_reloc_trans; + + /* + * infos of the currently processed inode. In case of deleted inodes, + * these are the values from the deleted inode. + */ + u64 cur_ino; + u64 cur_inode_gen; + u64 cur_inode_size; + u64 cur_inode_mode; + u64 cur_inode_rdev; + u64 cur_inode_last_extent; + u64 cur_inode_next_write_offset; + bool cur_inode_new; + bool cur_inode_new_gen; + bool cur_inode_deleted; + bool ignore_cur_inode; + bool cur_inode_needs_verity; + void *verity_descriptor; + + u64 send_progress; + + struct list_head new_refs; + struct list_head deleted_refs; + + struct radix_tree_root name_cache; + struct list_head name_cache_list; + int name_cache_size; + + /* + * The inode we are currently processing. It's not NULL only when we + * need to issue write commands for data extents from this inode. + */ + struct inode *cur_inode; + struct file_ra_state ra; + u64 page_cache_clear_start; + bool clean_page_cache; + + /* + * We process inodes by their increasing order, so if before an + * incremental send we reverse the parent/child relationship of + * directories such that a directory with a lower inode number was + * the parent of a directory with a higher inode number, and the one + * becoming the new parent got renamed too, we can't rename/move the + * directory with lower inode number when we finish processing it - we + * must process the directory with higher inode number first, then + * rename/move it and then rename/move the directory with lower inode + * number. Example follows. + * + * Tree state when the first send was performed: + * + * . + * |-- a (ino 257) + * |-- b (ino 258) + * | + * | + * |-- c (ino 259) + * | |-- d (ino 260) + * | + * |-- c2 (ino 261) + * + * Tree state when the second (incremental) send is performed: + * + * . + * |-- a (ino 257) + * |-- b (ino 258) + * |-- c2 (ino 261) + * |-- d2 (ino 260) + * |-- cc (ino 259) + * + * The sequence of steps that lead to the second state was: + * + * mv /a/b/c/d /a/b/c2/d2 + * mv /a/b/c /a/b/c2/d2/cc + * + * "c" has lower inode number, but we can't move it (2nd mv operation) + * before we move "d", which has higher inode number. + * + * So we just memorize which move/rename operations must be performed + * later when their respective parent is processed and moved/renamed. + */ + + /* Indexed by parent directory inode number. */ + struct rb_root pending_dir_moves; + + /* + * Reverse index, indexed by the inode number of a directory that + * is waiting for the move/rename of its immediate parent before its + * own move/rename can be performed. + */ + struct rb_root waiting_dir_moves; + + /* + * A directory that is going to be rm'ed might have a child directory + * which is in the pending directory moves index above. In this case, + * the directory can only be removed after the move/rename of its child + * is performed. Example: + * + * Parent snapshot: + * + * . (ino 256) + * |-- a/ (ino 257) + * |-- b/ (ino 258) + * |-- c/ (ino 259) + * | |-- x/ (ino 260) + * | + * |-- y/ (ino 261) + * + * Send snapshot: + * + * . (ino 256) + * |-- a/ (ino 257) + * |-- b/ (ino 258) + * |-- YY/ (ino 261) + * |-- x/ (ino 260) + * + * Sequence of steps that lead to the send snapshot: + * rm -f /a/b/c/foo.txt + * mv /a/b/y /a/b/YY + * mv /a/b/c/x /a/b/YY + * rmdir /a/b/c + * + * When the child is processed, its move/rename is delayed until its + * parent is processed (as explained above), but all other operations + * like update utimes, chown, chgrp, etc, are performed and the paths + * that it uses for those operations must use the orphanized name of + * its parent (the directory we're going to rm later), so we need to + * memorize that name. + * + * Indexed by the inode number of the directory to be deleted. + */ + struct rb_root orphan_dirs; + + struct rb_root rbtree_new_refs; + struct rb_root rbtree_deleted_refs; +}; + +struct pending_dir_move { + struct rb_node node; + struct list_head list; + u64 parent_ino; + u64 ino; + u64 gen; + struct list_head update_refs; +}; + +struct waiting_dir_move { + struct rb_node node; + u64 ino; + /* + * There might be some directory that could not be removed because it + * was waiting for this directory inode to be moved first. Therefore + * after this directory is moved, we can try to rmdir the ino rmdir_ino. + */ + u64 rmdir_ino; + u64 rmdir_gen; + bool orphanized; +}; + +struct orphan_dir_info { + struct rb_node node; + u64 ino; + u64 gen; + u64 last_dir_index_offset; +}; + +struct name_cache_entry { + struct list_head list; + /* + * radix_tree has only 32bit entries but we need to handle 64bit inums. + * We use the lower 32bit of the 64bit inum to store it in the tree. If + * more then one inum would fall into the same entry, we use radix_list + * to store the additional entries. radix_list is also used to store + * entries where two entries have the same inum but different + * generations. + */ + struct list_head radix_list; + u64 ino; + u64 gen; + u64 parent_ino; + u64 parent_gen; + int ret; + int need_later_update; + int name_len; + char name[]; +}; + +#define ADVANCE 1 +#define ADVANCE_ONLY_NEXT -1 + +enum btrfs_compare_tree_result { + BTRFS_COMPARE_TREE_NEW, + BTRFS_COMPARE_TREE_DELETED, + BTRFS_COMPARE_TREE_CHANGED, + BTRFS_COMPARE_TREE_SAME, +}; + +__cold +static void inconsistent_snapshot_error(struct send_ctx *sctx, + enum btrfs_compare_tree_result result, + const char *what) +{ + const char *result_string; + + switch (result) { + case BTRFS_COMPARE_TREE_NEW: + result_string = "new"; + break; + case BTRFS_COMPARE_TREE_DELETED: + result_string = "deleted"; + break; + case BTRFS_COMPARE_TREE_CHANGED: + result_string = "updated"; + break; + case BTRFS_COMPARE_TREE_SAME: + ASSERT(0); + result_string = "unchanged"; + break; + default: + ASSERT(0); + result_string = "unexpected"; + } + + btrfs_err(sctx->send_root->fs_info, + "Send: inconsistent snapshot, found %s %s for inode %llu without updated inode item, send root is %llu, parent root is %llu", + result_string, what, sctx->cmp_key->objectid, + sctx->send_root->root_key.objectid, + (sctx->parent_root ? + sctx->parent_root->root_key.objectid : 0)); +} + +__maybe_unused +static bool proto_cmd_ok(const struct send_ctx *sctx, int cmd) +{ + switch (sctx->proto) { + case 1: return cmd <= BTRFS_SEND_C_MAX_V1; + case 2: return cmd <= BTRFS_SEND_C_MAX_V2; + case 3: return cmd <= BTRFS_SEND_C_MAX_V3; + default: return false; + } +} + +static int is_waiting_for_move(struct send_ctx *sctx, u64 ino); + +static struct waiting_dir_move * +get_waiting_dir_move(struct send_ctx *sctx, u64 ino); + +static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen); + +static int need_send_hole(struct send_ctx *sctx) +{ + return (sctx->parent_root && !sctx->cur_inode_new && + !sctx->cur_inode_new_gen && !sctx->cur_inode_deleted && + S_ISREG(sctx->cur_inode_mode)); +} + +static void fs_path_reset(struct fs_path *p) +{ + if (p->reversed) { + p->start = p->buf + p->buf_len - 1; + p->end = p->start; + *p->start = 0; + } else { + p->start = p->buf; + p->end = p->start; + *p->start = 0; + } +} + +static struct fs_path *fs_path_alloc(void) +{ + struct fs_path *p; + + p = kmalloc(sizeof(*p), GFP_KERNEL); + if (!p) + return NULL; + p->reversed = 0; + p->buf = p->inline_buf; + p->buf_len = FS_PATH_INLINE_SIZE; + fs_path_reset(p); + return p; +} + +static struct fs_path *fs_path_alloc_reversed(void) +{ + struct fs_path *p; + + p = fs_path_alloc(); + if (!p) + return NULL; + p->reversed = 1; + fs_path_reset(p); + return p; +} + +static void fs_path_free(struct fs_path *p) +{ + if (!p) + return; + if (p->buf != p->inline_buf) + kfree(p->buf); + kfree(p); +} + +static int fs_path_len(struct fs_path *p) +{ + return p->end - p->start; +} + +static int fs_path_ensure_buf(struct fs_path *p, int len) +{ + char *tmp_buf; + int path_len; + int old_buf_len; + + len++; + + if (p->buf_len >= len) + return 0; + + if (len > PATH_MAX) { + WARN_ON(1); + return -ENOMEM; + } + + path_len = p->end - p->start; + old_buf_len = p->buf_len; + + /* + * First time the inline_buf does not suffice + */ + if (p->buf == p->inline_buf) { + tmp_buf = kmalloc(len, GFP_KERNEL); + if (tmp_buf) + memcpy(tmp_buf, p->buf, old_buf_len); + } else { + tmp_buf = krealloc(p->buf, len, GFP_KERNEL); + } + if (!tmp_buf) + return -ENOMEM; + p->buf = tmp_buf; + /* + * The real size of the buffer is bigger, this will let the fast path + * happen most of the time + */ + p->buf_len = ksize(p->buf); + + if (p->reversed) { + tmp_buf = p->buf + old_buf_len - path_len - 1; + p->end = p->buf + p->buf_len - 1; + p->start = p->end - path_len; + memmove(p->start, tmp_buf, path_len + 1); + } else { + p->start = p->buf; + p->end = p->start + path_len; + } + return 0; +} + +static int fs_path_prepare_for_add(struct fs_path *p, int name_len, + char **prepared) +{ + int ret; + int new_len; + + new_len = p->end - p->start + name_len; + if (p->start != p->end) + new_len++; + ret = fs_path_ensure_buf(p, new_len); + if (ret < 0) + goto out; + + if (p->reversed) { + if (p->start != p->end) + *--p->start = '/'; + p->start -= name_len; + *prepared = p->start; + } else { + if (p->start != p->end) + *p->end++ = '/'; + *prepared = p->end; + p->end += name_len; + *p->end = 0; + } + +out: + return ret; +} + +static int fs_path_add(struct fs_path *p, const char *name, int name_len) +{ + int ret; + char *prepared; + + ret = fs_path_prepare_for_add(p, name_len, &prepared); + if (ret < 0) + goto out; + memcpy(prepared, name, name_len); + +out: + return ret; +} + +static int fs_path_add_path(struct fs_path *p, struct fs_path *p2) +{ + int ret; + char *prepared; + + ret = fs_path_prepare_for_add(p, p2->end - p2->start, &prepared); + if (ret < 0) + goto out; + memcpy(prepared, p2->start, p2->end - p2->start); + +out: + return ret; +} + +static int fs_path_add_from_extent_buffer(struct fs_path *p, + struct extent_buffer *eb, + unsigned long off, int len) +{ + int ret; + char *prepared; + + ret = fs_path_prepare_for_add(p, len, &prepared); + if (ret < 0) + goto out; + + read_extent_buffer(eb, prepared, off, len); + +out: + return ret; +} + +static int fs_path_copy(struct fs_path *p, struct fs_path *from) +{ + p->reversed = from->reversed; + fs_path_reset(p); + + return fs_path_add_path(p, from); +} + +static void fs_path_unreverse(struct fs_path *p) +{ + char *tmp; + int len; + + if (!p->reversed) + return; + + tmp = p->start; + len = p->end - p->start; + p->start = p->buf; + p->end = p->start + len; + memmove(p->start, tmp, len + 1); + p->reversed = 0; +} + +static struct btrfs_path *alloc_path_for_send(void) +{ + struct btrfs_path *path; + + path = btrfs_alloc_path(); + if (!path) + return NULL; + path->search_commit_root = 1; + path->skip_locking = 1; + path->need_commit_sem = 1; + return path; +} + +static int write_buf(struct file *filp, const void *buf, u32 len, loff_t *off) +{ + int ret; + u32 pos = 0; + + while (pos < len) { + ret = kernel_write(filp, buf + pos, len - pos, off); + if (ret < 0) + return ret; + if (ret == 0) + return -EIO; + pos += ret; + } + + return 0; +} + +static int tlv_put(struct send_ctx *sctx, u16 attr, const void *data, int len) +{ + struct btrfs_tlv_header *hdr; + int total_len = sizeof(*hdr) + len; + int left = sctx->send_max_size - sctx->send_size; + + if (WARN_ON_ONCE(sctx->put_data)) + return -EINVAL; + + if (unlikely(left < total_len)) + return -EOVERFLOW; + + hdr = (struct btrfs_tlv_header *) (sctx->send_buf + sctx->send_size); + put_unaligned_le16(attr, &hdr->tlv_type); + put_unaligned_le16(len, &hdr->tlv_len); + memcpy(hdr + 1, data, len); + sctx->send_size += total_len; + + return 0; +} + +#define TLV_PUT_DEFINE_INT(bits) \ + static int tlv_put_u##bits(struct send_ctx *sctx, \ + u##bits attr, u##bits value) \ + { \ + __le##bits __tmp = cpu_to_le##bits(value); \ + return tlv_put(sctx, attr, &__tmp, sizeof(__tmp)); \ + } + +TLV_PUT_DEFINE_INT(8) +TLV_PUT_DEFINE_INT(32) +TLV_PUT_DEFINE_INT(64) + +static int tlv_put_string(struct send_ctx *sctx, u16 attr, + const char *str, int len) +{ + if (len == -1) + len = strlen(str); + return tlv_put(sctx, attr, str, len); +} + +static int tlv_put_uuid(struct send_ctx *sctx, u16 attr, + const u8 *uuid) +{ + return tlv_put(sctx, attr, uuid, BTRFS_UUID_SIZE); +} + +static int tlv_put_btrfs_timespec(struct send_ctx *sctx, u16 attr, + struct extent_buffer *eb, + struct btrfs_timespec *ts) +{ + struct btrfs_timespec bts; + read_extent_buffer(eb, &bts, (unsigned long)ts, sizeof(bts)); + return tlv_put(sctx, attr, &bts, sizeof(bts)); +} + + +#define TLV_PUT(sctx, attrtype, data, attrlen) \ + do { \ + ret = tlv_put(sctx, attrtype, data, attrlen); \ + if (ret < 0) \ + goto tlv_put_failure; \ + } while (0) + +#define TLV_PUT_INT(sctx, attrtype, bits, value) \ + do { \ + ret = tlv_put_u##bits(sctx, attrtype, value); \ + if (ret < 0) \ + goto tlv_put_failure; \ + } while (0) + +#define TLV_PUT_U8(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 8, data) +#define TLV_PUT_U16(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 16, data) +#define TLV_PUT_U32(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 32, data) +#define TLV_PUT_U64(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 64, data) +#define TLV_PUT_STRING(sctx, attrtype, str, len) \ + do { \ + ret = tlv_put_string(sctx, attrtype, str, len); \ + if (ret < 0) \ + goto tlv_put_failure; \ + } while (0) +#define TLV_PUT_PATH(sctx, attrtype, p) \ + do { \ + ret = tlv_put_string(sctx, attrtype, p->start, \ + p->end - p->start); \ + if (ret < 0) \ + goto tlv_put_failure; \ + } while(0) +#define TLV_PUT_UUID(sctx, attrtype, uuid) \ + do { \ + ret = tlv_put_uuid(sctx, attrtype, uuid); \ + if (ret < 0) \ + goto tlv_put_failure; \ + } while (0) +#define TLV_PUT_BTRFS_TIMESPEC(sctx, attrtype, eb, ts) \ + do { \ + ret = tlv_put_btrfs_timespec(sctx, attrtype, eb, ts); \ + if (ret < 0) \ + goto tlv_put_failure; \ + } while (0) + +static int send_header(struct send_ctx *sctx) +{ + struct btrfs_stream_header hdr; + + strcpy(hdr.magic, BTRFS_SEND_STREAM_MAGIC); + hdr.version = cpu_to_le32(sctx->proto); + return write_buf(sctx->send_filp, &hdr, sizeof(hdr), + &sctx->send_off); +} + +/* + * For each command/item we want to send to userspace, we call this function. + */ +static int begin_cmd(struct send_ctx *sctx, int cmd) +{ + struct btrfs_cmd_header *hdr; + + if (WARN_ON(!sctx->send_buf)) + return -EINVAL; + + BUG_ON(sctx->send_size); + + sctx->send_size += sizeof(*hdr); + hdr = (struct btrfs_cmd_header *)sctx->send_buf; + put_unaligned_le16(cmd, &hdr->cmd); + + return 0; +} + +static int send_cmd(struct send_ctx *sctx) +{ + int ret; + struct btrfs_cmd_header *hdr; + u32 crc; + + hdr = (struct btrfs_cmd_header *)sctx->send_buf; + put_unaligned_le32(sctx->send_size - sizeof(*hdr), &hdr->len); + put_unaligned_le32(0, &hdr->crc); + + crc = btrfs_crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size); + put_unaligned_le32(crc, &hdr->crc); + + ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size, + &sctx->send_off); + + sctx->send_size = 0; + sctx->put_data = false; + + return ret; +} + +/* + * Sends a move instruction to user space + */ +static int send_rename(struct send_ctx *sctx, + struct fs_path *from, struct fs_path *to) +{ + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + int ret; + + btrfs_debug(fs_info, "send_rename %s -> %s", from->start, to->start); + + ret = begin_cmd(sctx, BTRFS_SEND_C_RENAME); + if (ret < 0) + goto out; + + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, from); + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_TO, to); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + return ret; +} + +/* + * Sends a link instruction to user space + */ +static int send_link(struct send_ctx *sctx, + struct fs_path *path, struct fs_path *lnk) +{ + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + int ret; + + btrfs_debug(fs_info, "send_link %s -> %s", path->start, lnk->start); + + ret = begin_cmd(sctx, BTRFS_SEND_C_LINK); + if (ret < 0) + goto out; + + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, lnk); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + return ret; +} + +/* + * Sends an unlink instruction to user space + */ +static int send_unlink(struct send_ctx *sctx, struct fs_path *path) +{ + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + int ret; + + btrfs_debug(fs_info, "send_unlink %s", path->start); + + ret = begin_cmd(sctx, BTRFS_SEND_C_UNLINK); + if (ret < 0) + goto out; + + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + return ret; +} + +/* + * Sends a rmdir instruction to user space + */ +static int send_rmdir(struct send_ctx *sctx, struct fs_path *path) +{ + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + int ret; + + btrfs_debug(fs_info, "send_rmdir %s", path->start); + + ret = begin_cmd(sctx, BTRFS_SEND_C_RMDIR); + if (ret < 0) + goto out; + + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + return ret; +} + +struct btrfs_inode_info { + u64 size; + u64 gen; + u64 mode; + u64 uid; + u64 gid; + u64 rdev; + u64 fileattr; + u64 nlink; +}; + +/* + * Helper function to retrieve some fields from an inode item. + */ +static int get_inode_info(struct btrfs_root *root, u64 ino, + struct btrfs_inode_info *info) +{ + int ret; + struct btrfs_path *path; + struct btrfs_inode_item *ii; + struct btrfs_key key; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + key.objectid = ino; + key.type = BTRFS_INODE_ITEM_KEY; + key.offset = 0; + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret) { + if (ret > 0) + ret = -ENOENT; + goto out; + } + + if (!info) + goto out; + + ii = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_inode_item); + info->size = btrfs_inode_size(path->nodes[0], ii); + info->gen = btrfs_inode_generation(path->nodes[0], ii); + info->mode = btrfs_inode_mode(path->nodes[0], ii); + info->uid = btrfs_inode_uid(path->nodes[0], ii); + info->gid = btrfs_inode_gid(path->nodes[0], ii); + info->rdev = btrfs_inode_rdev(path->nodes[0], ii); + info->nlink = btrfs_inode_nlink(path->nodes[0], ii); + /* + * Transfer the unchanged u64 value of btrfs_inode_item::flags, that's + * otherwise logically split to 32/32 parts. + */ + info->fileattr = btrfs_inode_flags(path->nodes[0], ii); + +out: + btrfs_free_path(path); + return ret; +} + +static int get_inode_gen(struct btrfs_root *root, u64 ino, u64 *gen) +{ + int ret; + struct btrfs_inode_info info; + + if (!gen) + return -EPERM; + + ret = get_inode_info(root, ino, &info); + if (!ret) + *gen = info.gen; + return ret; +} + +typedef int (*iterate_inode_ref_t)(int num, u64 dir, int index, + struct fs_path *p, + void *ctx); + +/* + * Helper function to iterate the entries in ONE btrfs_inode_ref or + * btrfs_inode_extref. + * The iterate callback may return a non zero value to stop iteration. This can + * be a negative value for error codes or 1 to simply stop it. + * + * path must point to the INODE_REF or INODE_EXTREF when called. + */ +static int iterate_inode_ref(struct btrfs_root *root, struct btrfs_path *path, + struct btrfs_key *found_key, int resolve, + iterate_inode_ref_t iterate, void *ctx) +{ + struct extent_buffer *eb = path->nodes[0]; + struct btrfs_inode_ref *iref; + struct btrfs_inode_extref *extref; + struct btrfs_path *tmp_path; + struct fs_path *p; + u32 cur = 0; + u32 total; + int slot = path->slots[0]; + u32 name_len; + char *start; + int ret = 0; + int num = 0; + int index; + u64 dir; + unsigned long name_off; + unsigned long elem_size; + unsigned long ptr; + + p = fs_path_alloc_reversed(); + if (!p) + return -ENOMEM; + + tmp_path = alloc_path_for_send(); + if (!tmp_path) { + fs_path_free(p); + return -ENOMEM; + } + + + if (found_key->type == BTRFS_INODE_REF_KEY) { + ptr = (unsigned long)btrfs_item_ptr(eb, slot, + struct btrfs_inode_ref); + total = btrfs_item_size(eb, slot); + elem_size = sizeof(*iref); + } else { + ptr = btrfs_item_ptr_offset(eb, slot); + total = btrfs_item_size(eb, slot); + elem_size = sizeof(*extref); + } + + while (cur < total) { + fs_path_reset(p); + + if (found_key->type == BTRFS_INODE_REF_KEY) { + iref = (struct btrfs_inode_ref *)(ptr + cur); + name_len = btrfs_inode_ref_name_len(eb, iref); + name_off = (unsigned long)(iref + 1); + index = btrfs_inode_ref_index(eb, iref); + dir = found_key->offset; + } else { + extref = (struct btrfs_inode_extref *)(ptr + cur); + name_len = btrfs_inode_extref_name_len(eb, extref); + name_off = (unsigned long)&extref->name; + index = btrfs_inode_extref_index(eb, extref); + dir = btrfs_inode_extref_parent(eb, extref); + } + + if (resolve) { + start = btrfs_ref_to_path(root, tmp_path, name_len, + name_off, eb, dir, + p->buf, p->buf_len); + if (IS_ERR(start)) { + ret = PTR_ERR(start); + goto out; + } + if (start < p->buf) { + /* overflow , try again with larger buffer */ + ret = fs_path_ensure_buf(p, + p->buf_len + p->buf - start); + if (ret < 0) + goto out; + start = btrfs_ref_to_path(root, tmp_path, + name_len, name_off, + eb, dir, + p->buf, p->buf_len); + if (IS_ERR(start)) { + ret = PTR_ERR(start); + goto out; + } + BUG_ON(start < p->buf); + } + p->start = start; + } else { + ret = fs_path_add_from_extent_buffer(p, eb, name_off, + name_len); + if (ret < 0) + goto out; + } + + cur += elem_size + name_len; + ret = iterate(num, dir, index, p, ctx); + if (ret) + goto out; + num++; + } + +out: + btrfs_free_path(tmp_path); + fs_path_free(p); + return ret; +} + +typedef int (*iterate_dir_item_t)(int num, struct btrfs_key *di_key, + const char *name, int name_len, + const char *data, int data_len, + void *ctx); + +/* + * Helper function to iterate the entries in ONE btrfs_dir_item. + * The iterate callback may return a non zero value to stop iteration. This can + * be a negative value for error codes or 1 to simply stop it. + * + * path must point to the dir item when called. + */ +static int iterate_dir_item(struct btrfs_root *root, struct btrfs_path *path, + iterate_dir_item_t iterate, void *ctx) +{ + int ret = 0; + struct extent_buffer *eb; + struct btrfs_dir_item *di; + struct btrfs_key di_key; + char *buf = NULL; + int buf_len; + u32 name_len; + u32 data_len; + u32 cur; + u32 len; + u32 total; + int slot; + int num; + + /* + * Start with a small buffer (1 page). If later we end up needing more + * space, which can happen for xattrs on a fs with a leaf size greater + * then the page size, attempt to increase the buffer. Typically xattr + * values are small. + */ + buf_len = PATH_MAX; + buf = kmalloc(buf_len, GFP_KERNEL); + if (!buf) { + ret = -ENOMEM; + goto out; + } + + eb = path->nodes[0]; + slot = path->slots[0]; + di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item); + cur = 0; + len = 0; + total = btrfs_item_size(eb, slot); + + num = 0; + while (cur < total) { + name_len = btrfs_dir_name_len(eb, di); + data_len = btrfs_dir_data_len(eb, di); + btrfs_dir_item_key_to_cpu(eb, di, &di_key); + + if (btrfs_dir_type(eb, di) == BTRFS_FT_XATTR) { + if (name_len > XATTR_NAME_MAX) { + ret = -ENAMETOOLONG; + goto out; + } + if (name_len + data_len > + BTRFS_MAX_XATTR_SIZE(root->fs_info)) { + ret = -E2BIG; + goto out; + } + } else { + /* + * Path too long + */ + if (name_len + data_len > PATH_MAX) { + ret = -ENAMETOOLONG; + goto out; + } + } + + if (name_len + data_len > buf_len) { + buf_len = name_len + data_len; + if (is_vmalloc_addr(buf)) { + vfree(buf); + buf = NULL; + } else { + char *tmp = krealloc(buf, buf_len, + GFP_KERNEL | __GFP_NOWARN); + + if (!tmp) + kfree(buf); + buf = tmp; + } + if (!buf) { + buf = kvmalloc(buf_len, GFP_KERNEL); + if (!buf) { + ret = -ENOMEM; + goto out; + } + } + } + + read_extent_buffer(eb, buf, (unsigned long)(di + 1), + name_len + data_len); + + len = sizeof(*di) + name_len + data_len; + di = (struct btrfs_dir_item *)((char *)di + len); + cur += len; + + ret = iterate(num, &di_key, buf, name_len, buf + name_len, + data_len, ctx); + if (ret < 0) + goto out; + if (ret) { + ret = 0; + goto out; + } + + num++; + } + +out: + kvfree(buf); + return ret; +} + +static int __copy_first_ref(int num, u64 dir, int index, + struct fs_path *p, void *ctx) +{ + int ret; + struct fs_path *pt = ctx; + + ret = fs_path_copy(pt, p); + if (ret < 0) + return ret; + + /* we want the first only */ + return 1; +} + +/* + * Retrieve the first path of an inode. If an inode has more then one + * ref/hardlink, this is ignored. + */ +static int get_inode_path(struct btrfs_root *root, + u64 ino, struct fs_path *path) +{ + int ret; + struct btrfs_key key, found_key; + struct btrfs_path *p; + + p = alloc_path_for_send(); + if (!p) + return -ENOMEM; + + fs_path_reset(path); + + key.objectid = ino; + key.type = BTRFS_INODE_REF_KEY; + key.offset = 0; + + ret = btrfs_search_slot_for_read(root, &key, p, 1, 0); + if (ret < 0) + goto out; + if (ret) { + ret = 1; + goto out; + } + btrfs_item_key_to_cpu(p->nodes[0], &found_key, p->slots[0]); + if (found_key.objectid != ino || + (found_key.type != BTRFS_INODE_REF_KEY && + found_key.type != BTRFS_INODE_EXTREF_KEY)) { + ret = -ENOENT; + goto out; + } + + ret = iterate_inode_ref(root, p, &found_key, 1, + __copy_first_ref, path); + if (ret < 0) + goto out; + ret = 0; + +out: + btrfs_free_path(p); + return ret; +} + +struct backref_ctx { + struct send_ctx *sctx; + + /* number of total found references */ + u64 found; + + /* + * used for clones found in send_root. clones found behind cur_objectid + * and cur_offset are not considered as allowed clones. + */ + u64 cur_objectid; + u64 cur_offset; + + /* may be truncated in case it's the last extent in a file */ + u64 extent_len; + + /* Just to check for bugs in backref resolving */ + int found_itself; +}; + +static int __clone_root_cmp_bsearch(const void *key, const void *elt) +{ + u64 root = (u64)(uintptr_t)key; + const struct clone_root *cr = elt; + + if (root < cr->root->root_key.objectid) + return -1; + if (root > cr->root->root_key.objectid) + return 1; + return 0; +} + +static int __clone_root_cmp_sort(const void *e1, const void *e2) +{ + const struct clone_root *cr1 = e1; + const struct clone_root *cr2 = e2; + + if (cr1->root->root_key.objectid < cr2->root->root_key.objectid) + return -1; + if (cr1->root->root_key.objectid > cr2->root->root_key.objectid) + return 1; + return 0; +} + +/* + * Called for every backref that is found for the current extent. + * Results are collected in sctx->clone_roots->ino/offset/found_refs + */ +static int __iterate_backrefs(u64 ino, u64 offset, u64 root, void *ctx_) +{ + struct backref_ctx *bctx = ctx_; + struct clone_root *found; + + /* First check if the root is in the list of accepted clone sources */ + found = bsearch((void *)(uintptr_t)root, bctx->sctx->clone_roots, + bctx->sctx->clone_roots_cnt, + sizeof(struct clone_root), + __clone_root_cmp_bsearch); + if (!found) + return 0; + + if (found->root == bctx->sctx->send_root && + ino == bctx->cur_objectid && + offset == bctx->cur_offset) { + bctx->found_itself = 1; + } + + /* + * Make sure we don't consider clones from send_root that are + * behind the current inode/offset. + */ + if (found->root == bctx->sctx->send_root) { + /* + * If the source inode was not yet processed we can't issue a + * clone operation, as the source extent does not exist yet at + * the destination of the stream. + */ + if (ino > bctx->cur_objectid) + return 0; + /* + * We clone from the inode currently being sent as long as the + * source extent is already processed, otherwise we could try + * to clone from an extent that does not exist yet at the + * destination of the stream. + */ + if (ino == bctx->cur_objectid && + offset + bctx->extent_len > + bctx->sctx->cur_inode_next_write_offset) + return 0; + } + + bctx->found++; + found->found_refs++; + if (ino < found->ino) { + found->ino = ino; + found->offset = offset; + } else if (found->ino == ino) { + /* + * same extent found more then once in the same file. + */ + if (found->offset > offset + bctx->extent_len) + found->offset = offset; + } + + return 0; +} + +/* + * Given an inode, offset and extent item, it finds a good clone for a clone + * instruction. Returns -ENOENT when none could be found. The function makes + * sure that the returned clone is usable at the point where sending is at the + * moment. This means, that no clones are accepted which lie behind the current + * inode+offset. + * + * path must point to the extent item when called. + */ +static int find_extent_clone(struct send_ctx *sctx, + struct btrfs_path *path, + u64 ino, u64 data_offset, + u64 ino_size, + struct clone_root **found) +{ + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + int ret; + int extent_type; + u64 logical; + u64 disk_byte; + u64 num_bytes; + u64 extent_item_pos; + u64 flags = 0; + struct btrfs_file_extent_item *fi; + struct extent_buffer *eb = path->nodes[0]; + struct backref_ctx backref_ctx = {0}; + struct clone_root *cur_clone_root; + struct btrfs_key found_key; + struct btrfs_path *tmp_path; + struct btrfs_extent_item *ei; + int compressed; + u32 i; + + tmp_path = alloc_path_for_send(); + if (!tmp_path) + return -ENOMEM; + + /* We only use this path under the commit sem */ + tmp_path->need_commit_sem = 0; + + if (data_offset >= ino_size) { + /* + * There may be extents that lie behind the file's size. + * I at least had this in combination with snapshotting while + * writing large files. + */ + ret = 0; + goto out; + } + + fi = btrfs_item_ptr(eb, path->slots[0], + struct btrfs_file_extent_item); + extent_type = btrfs_file_extent_type(eb, fi); + if (extent_type == BTRFS_FILE_EXTENT_INLINE) { + ret = -ENOENT; + goto out; + } + compressed = btrfs_file_extent_compression(eb, fi); + + num_bytes = btrfs_file_extent_num_bytes(eb, fi); + disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); + if (disk_byte == 0) { + ret = -ENOENT; + goto out; + } + logical = disk_byte + btrfs_file_extent_offset(eb, fi); + + down_read(&fs_info->commit_root_sem); + ret = extent_from_logical(fs_info, disk_byte, tmp_path, + &found_key, &flags); + up_read(&fs_info->commit_root_sem); + + if (ret < 0) + goto out; + if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { + ret = -EIO; + goto out; + } + + ei = btrfs_item_ptr(tmp_path->nodes[0], tmp_path->slots[0], + struct btrfs_extent_item); + /* + * Backreference walking (iterate_extent_inodes() below) is currently + * too expensive when an extent has a large number of references, both + * in time spent and used memory. So for now just fallback to write + * operations instead of clone operations when an extent has more than + * a certain amount of references. + */ + if (btrfs_extent_refs(tmp_path->nodes[0], ei) > SEND_MAX_EXTENT_REFS) { + ret = -ENOENT; + goto out; + } + btrfs_release_path(tmp_path); + + /* + * Setup the clone roots. + */ + for (i = 0; i < sctx->clone_roots_cnt; i++) { + cur_clone_root = sctx->clone_roots + i; + cur_clone_root->ino = (u64)-1; + cur_clone_root->offset = 0; + cur_clone_root->found_refs = 0; + } + + backref_ctx.sctx = sctx; + backref_ctx.found = 0; + backref_ctx.cur_objectid = ino; + backref_ctx.cur_offset = data_offset; + backref_ctx.found_itself = 0; + backref_ctx.extent_len = num_bytes; + + /* + * The last extent of a file may be too large due to page alignment. + * We need to adjust extent_len in this case so that the checks in + * __iterate_backrefs work. + */ + if (data_offset + num_bytes >= ino_size) + backref_ctx.extent_len = ino_size - data_offset; + + /* + * Now collect all backrefs. + */ + if (compressed == BTRFS_COMPRESS_NONE) + extent_item_pos = logical - found_key.objectid; + else + extent_item_pos = 0; + ret = iterate_extent_inodes(fs_info, found_key.objectid, + extent_item_pos, 1, __iterate_backrefs, + &backref_ctx, false); + + if (ret < 0) + goto out; + + down_read(&fs_info->commit_root_sem); + if (fs_info->last_reloc_trans > sctx->last_reloc_trans) { + /* + * A transaction commit for a transaction in which block group + * relocation was done just happened. + * The disk_bytenr of the file extent item we processed is + * possibly stale, referring to the extent's location before + * relocation. So act as if we haven't found any clone sources + * and fallback to write commands, which will read the correct + * data from the new extent location. Otherwise we will fail + * below because we haven't found our own back reference or we + * could be getting incorrect sources in case the old extent + * was already reallocated after the relocation. + */ + up_read(&fs_info->commit_root_sem); + ret = -ENOENT; + goto out; + } + up_read(&fs_info->commit_root_sem); + + if (!backref_ctx.found_itself) { + /* found a bug in backref code? */ + ret = -EIO; + btrfs_err(fs_info, + "did not find backref in send_root. inode=%llu, offset=%llu, disk_byte=%llu found extent=%llu", + ino, data_offset, disk_byte, found_key.objectid); + goto out; + } + + btrfs_debug(fs_info, + "find_extent_clone: data_offset=%llu, ino=%llu, num_bytes=%llu, logical=%llu", + data_offset, ino, num_bytes, logical); + + if (!backref_ctx.found) + btrfs_debug(fs_info, "no clones found"); + + cur_clone_root = NULL; + for (i = 0; i < sctx->clone_roots_cnt; i++) { + if (sctx->clone_roots[i].found_refs) { + if (!cur_clone_root) + cur_clone_root = sctx->clone_roots + i; + else if (sctx->clone_roots[i].root == sctx->send_root) + /* prefer clones from send_root over others */ + cur_clone_root = sctx->clone_roots + i; + } + + } + + if (cur_clone_root) { + *found = cur_clone_root; + ret = 0; + } else { + ret = -ENOENT; + } + +out: + btrfs_free_path(tmp_path); + return ret; +} + +static int read_symlink(struct btrfs_root *root, + u64 ino, + struct fs_path *dest) +{ + int ret; + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_file_extent_item *ei; + u8 type; + u8 compression; + unsigned long off; + int len; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + key.objectid = ino; + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = 0; + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) + goto out; + if (ret) { + /* + * An empty symlink inode. Can happen in rare error paths when + * creating a symlink (transaction committed before the inode + * eviction handler removed the symlink inode items and a crash + * happened in between or the subvol was snapshoted in between). + * Print an informative message to dmesg/syslog so that the user + * can delete the symlink. + */ + btrfs_err(root->fs_info, + "Found empty symlink inode %llu at root %llu", + ino, root->root_key.objectid); + ret = -EIO; + goto out; + } + + ei = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_file_extent_item); + type = btrfs_file_extent_type(path->nodes[0], ei); + compression = btrfs_file_extent_compression(path->nodes[0], ei); + BUG_ON(type != BTRFS_FILE_EXTENT_INLINE); + BUG_ON(compression); + + off = btrfs_file_extent_inline_start(ei); + len = btrfs_file_extent_ram_bytes(path->nodes[0], ei); + + ret = fs_path_add_from_extent_buffer(dest, path->nodes[0], off, len); + +out: + btrfs_free_path(path); + return ret; +} + +/* + * Helper function to generate a file name that is unique in the root of + * send_root and parent_root. This is used to generate names for orphan inodes. + */ +static int gen_unique_name(struct send_ctx *sctx, + u64 ino, u64 gen, + struct fs_path *dest) +{ + int ret = 0; + struct btrfs_path *path; + struct btrfs_dir_item *di; + char tmp[64]; + int len; + u64 idx = 0; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + while (1) { + struct fscrypt_str tmp_name; + + len = snprintf(tmp, sizeof(tmp), "o%llu-%llu-%llu", + ino, gen, idx); + ASSERT(len < sizeof(tmp)); + tmp_name.name = tmp; + tmp_name.len = strlen(tmp); + + di = btrfs_lookup_dir_item(NULL, sctx->send_root, + path, BTRFS_FIRST_FREE_OBJECTID, + &tmp_name, 0); + btrfs_release_path(path); + if (IS_ERR(di)) { + ret = PTR_ERR(di); + goto out; + } + if (di) { + /* not unique, try again */ + idx++; + continue; + } + + if (!sctx->parent_root) { + /* unique */ + ret = 0; + break; + } + + di = btrfs_lookup_dir_item(NULL, sctx->parent_root, + path, BTRFS_FIRST_FREE_OBJECTID, + &tmp_name, 0); + btrfs_release_path(path); + if (IS_ERR(di)) { + ret = PTR_ERR(di); + goto out; + } + if (di) { + /* not unique, try again */ + idx++; + continue; + } + /* unique */ + break; + } + + ret = fs_path_add(dest, tmp, strlen(tmp)); + +out: + btrfs_free_path(path); + return ret; +} + +enum inode_state { + inode_state_no_change, + inode_state_will_create, + inode_state_did_create, + inode_state_will_delete, + inode_state_did_delete, +}; + +static int get_cur_inode_state(struct send_ctx *sctx, u64 ino, u64 gen) +{ + int ret; + int left_ret; + int right_ret; + u64 left_gen; + u64 right_gen = 0; + struct btrfs_inode_info info; + + ret = get_inode_info(sctx->send_root, ino, &info); + if (ret < 0 && ret != -ENOENT) + goto out; + left_ret = (info.nlink == 0) ? -ENOENT : ret; + left_gen = info.gen; + + if (!sctx->parent_root) { + right_ret = -ENOENT; + } else { + ret = get_inode_info(sctx->parent_root, ino, &info); + if (ret < 0 && ret != -ENOENT) + goto out; + right_ret = (info.nlink == 0) ? -ENOENT : ret; + right_gen = info.gen; + } + + if (!left_ret && !right_ret) { + if (left_gen == gen && right_gen == gen) { + ret = inode_state_no_change; + } else if (left_gen == gen) { + if (ino < sctx->send_progress) + ret = inode_state_did_create; + else + ret = inode_state_will_create; + } else if (right_gen == gen) { + if (ino < sctx->send_progress) + ret = inode_state_did_delete; + else + ret = inode_state_will_delete; + } else { + ret = -ENOENT; + } + } else if (!left_ret) { + if (left_gen == gen) { + if (ino < sctx->send_progress) + ret = inode_state_did_create; + else + ret = inode_state_will_create; + } else { + ret = -ENOENT; + } + } else if (!right_ret) { + if (right_gen == gen) { + if (ino < sctx->send_progress) + ret = inode_state_did_delete; + else + ret = inode_state_will_delete; + } else { + ret = -ENOENT; + } + } else { + ret = -ENOENT; + } + +out: + return ret; +} + +static int is_inode_existent(struct send_ctx *sctx, u64 ino, u64 gen) +{ + int ret; + + if (ino == BTRFS_FIRST_FREE_OBJECTID) + return 1; + + ret = get_cur_inode_state(sctx, ino, gen); + if (ret < 0) + goto out; + + if (ret == inode_state_no_change || + ret == inode_state_did_create || + ret == inode_state_will_delete) + ret = 1; + else + ret = 0; + +out: + return ret; +} + +/* + * Helper function to lookup a dir item in a dir. + */ +static int lookup_dir_item_inode(struct btrfs_root *root, + u64 dir, const char *name, int name_len, + u64 *found_inode) +{ + int ret = 0; + struct btrfs_dir_item *di; + struct btrfs_key key; + struct btrfs_path *path; + struct fscrypt_str name_str = FSTR_INIT((char *)name, name_len); + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + di = btrfs_lookup_dir_item(NULL, root, path, dir, &name_str, 0); + if (IS_ERR_OR_NULL(di)) { + ret = di ? PTR_ERR(di) : -ENOENT; + goto out; + } + btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key); + if (key.type == BTRFS_ROOT_ITEM_KEY) { + ret = -ENOENT; + goto out; + } + *found_inode = key.objectid; + +out: + btrfs_free_path(path); + return ret; +} + +/* + * Looks up the first btrfs_inode_ref of a given ino. It returns the parent dir, + * generation of the parent dir and the name of the dir entry. + */ +static int get_first_ref(struct btrfs_root *root, u64 ino, + u64 *dir, u64 *dir_gen, struct fs_path *name) +{ + int ret; + struct btrfs_key key; + struct btrfs_key found_key; + struct btrfs_path *path; + int len; + u64 parent_dir; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + key.objectid = ino; + key.type = BTRFS_INODE_REF_KEY; + key.offset = 0; + + ret = btrfs_search_slot_for_read(root, &key, path, 1, 0); + if (ret < 0) + goto out; + if (!ret) + btrfs_item_key_to_cpu(path->nodes[0], &found_key, + path->slots[0]); + if (ret || found_key.objectid != ino || + (found_key.type != BTRFS_INODE_REF_KEY && + found_key.type != BTRFS_INODE_EXTREF_KEY)) { + ret = -ENOENT; + goto out; + } + + if (found_key.type == BTRFS_INODE_REF_KEY) { + struct btrfs_inode_ref *iref; + iref = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_inode_ref); + len = btrfs_inode_ref_name_len(path->nodes[0], iref); + ret = fs_path_add_from_extent_buffer(name, path->nodes[0], + (unsigned long)(iref + 1), + len); + parent_dir = found_key.offset; + } else { + struct btrfs_inode_extref *extref; + extref = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_inode_extref); + len = btrfs_inode_extref_name_len(path->nodes[0], extref); + ret = fs_path_add_from_extent_buffer(name, path->nodes[0], + (unsigned long)&extref->name, len); + parent_dir = btrfs_inode_extref_parent(path->nodes[0], extref); + } + if (ret < 0) + goto out; + btrfs_release_path(path); + + if (dir_gen) { + ret = get_inode_gen(root, parent_dir, dir_gen); + if (ret < 0) + goto out; + } + + *dir = parent_dir; + +out: + btrfs_free_path(path); + return ret; +} + +static int is_first_ref(struct btrfs_root *root, + u64 ino, u64 dir, + const char *name, int name_len) +{ + int ret; + struct fs_path *tmp_name; + u64 tmp_dir; + + tmp_name = fs_path_alloc(); + if (!tmp_name) + return -ENOMEM; + + ret = get_first_ref(root, ino, &tmp_dir, NULL, tmp_name); + if (ret < 0) + goto out; + + if (dir != tmp_dir || name_len != fs_path_len(tmp_name)) { + ret = 0; + goto out; + } + + ret = !memcmp(tmp_name->start, name, name_len); + +out: + fs_path_free(tmp_name); + return ret; +} + +/* + * Used by process_recorded_refs to determine if a new ref would overwrite an + * already existing ref. In case it detects an overwrite, it returns the + * inode/gen in who_ino/who_gen. + * When an overwrite is detected, process_recorded_refs does proper orphanizing + * to make sure later references to the overwritten inode are possible. + * Orphanizing is however only required for the first ref of an inode. + * process_recorded_refs does an additional is_first_ref check to see if + * orphanizing is really required. + */ +static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen, + const char *name, int name_len, + u64 *who_ino, u64 *who_gen, u64 *who_mode) +{ + int ret = 0; + u64 gen; + u64 other_inode = 0; + struct btrfs_inode_info info; + + if (!sctx->parent_root) + goto out; + + ret = is_inode_existent(sctx, dir, dir_gen); + if (ret <= 0) + goto out; + + /* + * If we have a parent root we need to verify that the parent dir was + * not deleted and then re-created, if it was then we have no overwrite + * and we can just unlink this entry. + */ + if (sctx->parent_root && dir != BTRFS_FIRST_FREE_OBJECTID) { + ret = get_inode_gen(sctx->parent_root, dir, &gen); + if (ret < 0 && ret != -ENOENT) + goto out; + if (ret) { + ret = 0; + goto out; + } + if (gen != dir_gen) + goto out; + } + + ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len, + &other_inode); + if (ret < 0 && ret != -ENOENT) + goto out; + if (ret) { + ret = 0; + goto out; + } + + /* + * Check if the overwritten ref was already processed. If yes, the ref + * was already unlinked/moved, so we can safely assume that we will not + * overwrite anything at this point in time. + */ + if (other_inode > sctx->send_progress || + is_waiting_for_move(sctx, other_inode)) { + ret = get_inode_info(sctx->parent_root, other_inode, &info); + if (ret < 0) + goto out; + + ret = 1; + *who_ino = other_inode; + *who_gen = info.gen; + *who_mode = info.mode; + } else { + ret = 0; + } + +out: + return ret; +} + +/* + * Checks if the ref was overwritten by an already processed inode. This is + * used by __get_cur_name_and_parent to find out if the ref was orphanized and + * thus the orphan name needs be used. + * process_recorded_refs also uses it to avoid unlinking of refs that were + * overwritten. + */ +static int did_overwrite_ref(struct send_ctx *sctx, + u64 dir, u64 dir_gen, + u64 ino, u64 ino_gen, + const char *name, int name_len) +{ + int ret = 0; + u64 gen; + u64 ow_inode; + + if (!sctx->parent_root) + goto out; + + ret = is_inode_existent(sctx, dir, dir_gen); + if (ret <= 0) + goto out; + + if (dir != BTRFS_FIRST_FREE_OBJECTID) { + ret = get_inode_gen(sctx->send_root, dir, &gen); + if (ret < 0 && ret != -ENOENT) + goto out; + if (ret) { + ret = 0; + goto out; + } + if (gen != dir_gen) + goto out; + } + + /* check if the ref was overwritten by another ref */ + ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len, + &ow_inode); + if (ret < 0 && ret != -ENOENT) + goto out; + if (ret) { + /* was never and will never be overwritten */ + ret = 0; + goto out; + } + + ret = get_inode_gen(sctx->send_root, ow_inode, &gen); + if (ret < 0) + goto out; + + if (ow_inode == ino && gen == ino_gen) { + ret = 0; + goto out; + } + + /* + * We know that it is or will be overwritten. Check this now. + * The current inode being processed might have been the one that caused + * inode 'ino' to be orphanized, therefore check if ow_inode matches + * the current inode being processed. + */ + if ((ow_inode < sctx->send_progress) || + (ino != sctx->cur_ino && ow_inode == sctx->cur_ino && + gen == sctx->cur_inode_gen)) + ret = 1; + else + ret = 0; + +out: + return ret; +} + +/* + * Same as did_overwrite_ref, but also checks if it is the first ref of an inode + * that got overwritten. This is used by process_recorded_refs to determine + * if it has to use the path as returned by get_cur_path or the orphan name. + */ +static int did_overwrite_first_ref(struct send_ctx *sctx, u64 ino, u64 gen) +{ + int ret = 0; + struct fs_path *name = NULL; + u64 dir; + u64 dir_gen; + + if (!sctx->parent_root) + goto out; + + name = fs_path_alloc(); + if (!name) + return -ENOMEM; + + ret = get_first_ref(sctx->parent_root, ino, &dir, &dir_gen, name); + if (ret < 0) + goto out; + + ret = did_overwrite_ref(sctx, dir, dir_gen, ino, gen, + name->start, fs_path_len(name)); + +out: + fs_path_free(name); + return ret; +} + +/* + * Insert a name cache entry. On 32bit kernels the radix tree index is 32bit, + * so we need to do some special handling in case we have clashes. This function + * takes care of this with the help of name_cache_entry::radix_list. + * In case of error, nce is kfreed. + */ +static int name_cache_insert(struct send_ctx *sctx, + struct name_cache_entry *nce) +{ + int ret = 0; + struct list_head *nce_head; + + nce_head = radix_tree_lookup(&sctx->name_cache, + (unsigned long)nce->ino); + if (!nce_head) { + nce_head = kmalloc(sizeof(*nce_head), GFP_KERNEL); + if (!nce_head) { + kfree(nce); + return -ENOMEM; + } + INIT_LIST_HEAD(nce_head); + + ret = radix_tree_insert(&sctx->name_cache, nce->ino, nce_head); + if (ret < 0) { + kfree(nce_head); + kfree(nce); + return ret; + } + } + list_add_tail(&nce->radix_list, nce_head); + list_add_tail(&nce->list, &sctx->name_cache_list); + sctx->name_cache_size++; + + return ret; +} + +static void name_cache_delete(struct send_ctx *sctx, + struct name_cache_entry *nce) +{ + struct list_head *nce_head; + + nce_head = radix_tree_lookup(&sctx->name_cache, + (unsigned long)nce->ino); + if (!nce_head) { + btrfs_err(sctx->send_root->fs_info, + "name_cache_delete lookup failed ino %llu cache size %d, leaking memory", + nce->ino, sctx->name_cache_size); + } + + list_del(&nce->radix_list); + list_del(&nce->list); + sctx->name_cache_size--; + + /* + * We may not get to the final release of nce_head if the lookup fails + */ + if (nce_head && list_empty(nce_head)) { + radix_tree_delete(&sctx->name_cache, (unsigned long)nce->ino); + kfree(nce_head); + } +} + +static struct name_cache_entry *name_cache_search(struct send_ctx *sctx, + u64 ino, u64 gen) +{ + struct list_head *nce_head; + struct name_cache_entry *cur; + + nce_head = radix_tree_lookup(&sctx->name_cache, (unsigned long)ino); + if (!nce_head) + return NULL; + + list_for_each_entry(cur, nce_head, radix_list) { + if (cur->ino == ino && cur->gen == gen) + return cur; + } + return NULL; +} + +/* + * Remove some entries from the beginning of name_cache_list. + */ +static void name_cache_clean_unused(struct send_ctx *sctx) +{ + struct name_cache_entry *nce; + + if (sctx->name_cache_size < SEND_CTX_NAME_CACHE_CLEAN_SIZE) + return; + + while (sctx->name_cache_size > SEND_CTX_MAX_NAME_CACHE_SIZE) { + nce = list_entry(sctx->name_cache_list.next, + struct name_cache_entry, list); + name_cache_delete(sctx, nce); + kfree(nce); + } +} + +static void name_cache_free(struct send_ctx *sctx) +{ + struct name_cache_entry *nce; + + while (!list_empty(&sctx->name_cache_list)) { + nce = list_entry(sctx->name_cache_list.next, + struct name_cache_entry, list); + name_cache_delete(sctx, nce); + kfree(nce); + } +} + +/* + * Used by get_cur_path for each ref up to the root. + * Returns 0 if it succeeded. + * Returns 1 if the inode is not existent or got overwritten. In that case, the + * name is an orphan name. This instructs get_cur_path to stop iterating. If 1 + * is returned, parent_ino/parent_gen are not guaranteed to be valid. + * Returns <0 in case of error. + */ +static int __get_cur_name_and_parent(struct send_ctx *sctx, + u64 ino, u64 gen, + u64 *parent_ino, + u64 *parent_gen, + struct fs_path *dest) +{ + int ret; + int nce_ret; + struct name_cache_entry *nce = NULL; + + /* + * First check if we already did a call to this function with the same + * ino/gen. If yes, check if the cache entry is still up-to-date. If yes + * return the cached result. + */ + nce = name_cache_search(sctx, ino, gen); + if (nce) { + if (ino < sctx->send_progress && nce->need_later_update) { + name_cache_delete(sctx, nce); + kfree(nce); + nce = NULL; + } else { + /* + * Removes the entry from the list and adds it back to + * the end. This marks the entry as recently used so + * that name_cache_clean_unused does not remove it. + */ + list_move_tail(&nce->list, &sctx->name_cache_list); + + *parent_ino = nce->parent_ino; + *parent_gen = nce->parent_gen; + ret = fs_path_add(dest, nce->name, nce->name_len); + if (ret < 0) + goto out; + ret = nce->ret; + goto out; + } + } + + /* + * If the inode is not existent yet, add the orphan name and return 1. + * This should only happen for the parent dir that we determine in + * record_new_ref_if_needed(). + */ + ret = is_inode_existent(sctx, ino, gen); + if (ret < 0) + goto out; + + if (!ret) { + ret = gen_unique_name(sctx, ino, gen, dest); + if (ret < 0) + goto out; + ret = 1; + goto out_cache; + } + + /* + * Depending on whether the inode was already processed or not, use + * send_root or parent_root for ref lookup. + */ + if (ino < sctx->send_progress) + ret = get_first_ref(sctx->send_root, ino, + parent_ino, parent_gen, dest); + else + ret = get_first_ref(sctx->parent_root, ino, + parent_ino, parent_gen, dest); + if (ret < 0) + goto out; + + /* + * Check if the ref was overwritten by an inode's ref that was processed + * earlier. If yes, treat as orphan and return 1. + */ + ret = did_overwrite_ref(sctx, *parent_ino, *parent_gen, ino, gen, + dest->start, dest->end - dest->start); + if (ret < 0) + goto out; + if (ret) { + fs_path_reset(dest); + ret = gen_unique_name(sctx, ino, gen, dest); + if (ret < 0) + goto out; + ret = 1; + } + +out_cache: + /* + * Store the result of the lookup in the name cache. + */ + nce = kmalloc(sizeof(*nce) + fs_path_len(dest) + 1, GFP_KERNEL); + if (!nce) { + ret = -ENOMEM; + goto out; + } + + nce->ino = ino; + nce->gen = gen; + nce->parent_ino = *parent_ino; + nce->parent_gen = *parent_gen; + nce->name_len = fs_path_len(dest); + nce->ret = ret; + strcpy(nce->name, dest->start); + + if (ino < sctx->send_progress) + nce->need_later_update = 0; + else + nce->need_later_update = 1; + + nce_ret = name_cache_insert(sctx, nce); + if (nce_ret < 0) + ret = nce_ret; + name_cache_clean_unused(sctx); + +out: + return ret; +} + +/* + * Magic happens here. This function returns the first ref to an inode as it + * would look like while receiving the stream at this point in time. + * We walk the path up to the root. For every inode in between, we check if it + * was already processed/sent. If yes, we continue with the parent as found + * in send_root. If not, we continue with the parent as found in parent_root. + * If we encounter an inode that was deleted at this point in time, we use the + * inodes "orphan" name instead of the real name and stop. Same with new inodes + * that were not created yet and overwritten inodes/refs. + * + * When do we have orphan inodes: + * 1. When an inode is freshly created and thus no valid refs are available yet + * 2. When a directory lost all it's refs (deleted) but still has dir items + * inside which were not processed yet (pending for move/delete). If anyone + * tried to get the path to the dir items, it would get a path inside that + * orphan directory. + * 3. When an inode is moved around or gets new links, it may overwrite the ref + * of an unprocessed inode. If in that case the first ref would be + * overwritten, the overwritten inode gets "orphanized". Later when we + * process this overwritten inode, it is restored at a new place by moving + * the orphan inode. + * + * sctx->send_progress tells this function at which point in time receiving + * would be. + */ +static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen, + struct fs_path *dest) +{ + int ret = 0; + struct fs_path *name = NULL; + u64 parent_inode = 0; + u64 parent_gen = 0; + int stop = 0; + + name = fs_path_alloc(); + if (!name) { + ret = -ENOMEM; + goto out; + } + + dest->reversed = 1; + fs_path_reset(dest); + + while (!stop && ino != BTRFS_FIRST_FREE_OBJECTID) { + struct waiting_dir_move *wdm; + + fs_path_reset(name); + + if (is_waiting_for_rm(sctx, ino, gen)) { + ret = gen_unique_name(sctx, ino, gen, name); + if (ret < 0) + goto out; + ret = fs_path_add_path(dest, name); + break; + } + + wdm = get_waiting_dir_move(sctx, ino); + if (wdm && wdm->orphanized) { + ret = gen_unique_name(sctx, ino, gen, name); + stop = 1; + } else if (wdm) { + ret = get_first_ref(sctx->parent_root, ino, + &parent_inode, &parent_gen, name); + } else { + ret = __get_cur_name_and_parent(sctx, ino, gen, + &parent_inode, + &parent_gen, name); + if (ret) + stop = 1; + } + + if (ret < 0) + goto out; + + ret = fs_path_add_path(dest, name); + if (ret < 0) + goto out; + + ino = parent_inode; + gen = parent_gen; + } + +out: + fs_path_free(name); + if (!ret) + fs_path_unreverse(dest); + return ret; +} + +/* + * Sends a BTRFS_SEND_C_SUBVOL command/item to userspace + */ +static int send_subvol_begin(struct send_ctx *sctx) +{ + int ret; + struct btrfs_root *send_root = sctx->send_root; + struct btrfs_root *parent_root = sctx->parent_root; + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_root_ref *ref; + struct extent_buffer *leaf; + char *name = NULL; + int namelen; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + name = kmalloc(BTRFS_PATH_NAME_MAX, GFP_KERNEL); + if (!name) { + btrfs_free_path(path); + return -ENOMEM; + } + + key.objectid = send_root->root_key.objectid; + key.type = BTRFS_ROOT_BACKREF_KEY; + key.offset = 0; + + ret = btrfs_search_slot_for_read(send_root->fs_info->tree_root, + &key, path, 1, 0); + if (ret < 0) + goto out; + if (ret) { + ret = -ENOENT; + goto out; + } + + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + if (key.type != BTRFS_ROOT_BACKREF_KEY || + key.objectid != send_root->root_key.objectid) { + ret = -ENOENT; + goto out; + } + ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref); + namelen = btrfs_root_ref_name_len(leaf, ref); + read_extent_buffer(leaf, name, (unsigned long)(ref + 1), namelen); + btrfs_release_path(path); + + if (parent_root) { + ret = begin_cmd(sctx, BTRFS_SEND_C_SNAPSHOT); + if (ret < 0) + goto out; + } else { + ret = begin_cmd(sctx, BTRFS_SEND_C_SUBVOL); + if (ret < 0) + goto out; + } + + TLV_PUT_STRING(sctx, BTRFS_SEND_A_PATH, name, namelen); + + if (!btrfs_is_empty_uuid(sctx->send_root->root_item.received_uuid)) + TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID, + sctx->send_root->root_item.received_uuid); + else + TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID, + sctx->send_root->root_item.uuid); + + TLV_PUT_U64(sctx, BTRFS_SEND_A_CTRANSID, + btrfs_root_ctransid(&sctx->send_root->root_item)); + if (parent_root) { + if (!btrfs_is_empty_uuid(parent_root->root_item.received_uuid)) + TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, + parent_root->root_item.received_uuid); + else + TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, + parent_root->root_item.uuid); + TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID, + btrfs_root_ctransid(&sctx->parent_root->root_item)); + } + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + btrfs_free_path(path); + kfree(name); + return ret; +} + +static int send_truncate(struct send_ctx *sctx, u64 ino, u64 gen, u64 size) +{ + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + int ret = 0; + struct fs_path *p; + + btrfs_debug(fs_info, "send_truncate %llu size=%llu", ino, size); + + p = fs_path_alloc(); + if (!p) + return -ENOMEM; + + ret = begin_cmd(sctx, BTRFS_SEND_C_TRUNCATE); + if (ret < 0) + goto out; + + ret = get_cur_path(sctx, ino, gen, p); + if (ret < 0) + goto out; + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); + TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, size); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + fs_path_free(p); + return ret; +} + +static int send_chmod(struct send_ctx *sctx, u64 ino, u64 gen, u64 mode) +{ + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + int ret = 0; + struct fs_path *p; + + btrfs_debug(fs_info, "send_chmod %llu mode=%llu", ino, mode); + + p = fs_path_alloc(); + if (!p) + return -ENOMEM; + + ret = begin_cmd(sctx, BTRFS_SEND_C_CHMOD); + if (ret < 0) + goto out; + + ret = get_cur_path(sctx, ino, gen, p); + if (ret < 0) + goto out; + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); + TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode & 07777); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + fs_path_free(p); + return ret; +} + +static int send_fileattr(struct send_ctx *sctx, u64 ino, u64 gen, u64 fileattr) +{ + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + int ret = 0; + struct fs_path *p; + + if (sctx->proto < 2) + return 0; + + btrfs_debug(fs_info, "send_fileattr %llu fileattr=%llu", ino, fileattr); + + p = fs_path_alloc(); + if (!p) + return -ENOMEM; + + ret = begin_cmd(sctx, BTRFS_SEND_C_FILEATTR); + if (ret < 0) + goto out; + + ret = get_cur_path(sctx, ino, gen, p); + if (ret < 0) + goto out; + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); + TLV_PUT_U64(sctx, BTRFS_SEND_A_FILEATTR, fileattr); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + fs_path_free(p); + return ret; +} + +static int send_chown(struct send_ctx *sctx, u64 ino, u64 gen, u64 uid, u64 gid) +{ + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + int ret = 0; + struct fs_path *p; + + btrfs_debug(fs_info, "send_chown %llu uid=%llu, gid=%llu", + ino, uid, gid); + + p = fs_path_alloc(); + if (!p) + return -ENOMEM; + + ret = begin_cmd(sctx, BTRFS_SEND_C_CHOWN); + if (ret < 0) + goto out; + + ret = get_cur_path(sctx, ino, gen, p); + if (ret < 0) + goto out; + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); + TLV_PUT_U64(sctx, BTRFS_SEND_A_UID, uid); + TLV_PUT_U64(sctx, BTRFS_SEND_A_GID, gid); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + fs_path_free(p); + return ret; +} + +static int send_utimes(struct send_ctx *sctx, u64 ino, u64 gen) +{ + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + int ret = 0; + struct fs_path *p = NULL; + struct btrfs_inode_item *ii; + struct btrfs_path *path = NULL; + struct extent_buffer *eb; + struct btrfs_key key; + int slot; + + btrfs_debug(fs_info, "send_utimes %llu", ino); + + p = fs_path_alloc(); + if (!p) + return -ENOMEM; + + path = alloc_path_for_send(); + if (!path) { + ret = -ENOMEM; + goto out; + } + + key.objectid = ino; + key.type = BTRFS_INODE_ITEM_KEY; + key.offset = 0; + ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0); + if (ret > 0) + ret = -ENOENT; + if (ret < 0) + goto out; + + eb = path->nodes[0]; + slot = path->slots[0]; + ii = btrfs_item_ptr(eb, slot, struct btrfs_inode_item); + + ret = begin_cmd(sctx, BTRFS_SEND_C_UTIMES); + if (ret < 0) + goto out; + + ret = get_cur_path(sctx, ino, gen, p); + if (ret < 0) + goto out; + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); + TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_ATIME, eb, &ii->atime); + TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_MTIME, eb, &ii->mtime); + TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_CTIME, eb, &ii->ctime); + if (sctx->proto >= 2) + TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_OTIME, eb, &ii->otime); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + fs_path_free(p); + btrfs_free_path(path); + return ret; +} + +/* + * Sends a BTRFS_SEND_C_MKXXX or SYMLINK command to user space. We don't have + * a valid path yet because we did not process the refs yet. So, the inode + * is created as orphan. + */ +static int send_create_inode(struct send_ctx *sctx, u64 ino) +{ + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + int ret = 0; + struct fs_path *p; + int cmd; + struct btrfs_inode_info info; + u64 gen; + u64 mode; + u64 rdev; + + btrfs_debug(fs_info, "send_create_inode %llu", ino); + + p = fs_path_alloc(); + if (!p) + return -ENOMEM; + + if (ino != sctx->cur_ino) { + ret = get_inode_info(sctx->send_root, ino, &info); + if (ret < 0) + goto out; + gen = info.gen; + mode = info.mode; + rdev = info.rdev; + } else { + gen = sctx->cur_inode_gen; + mode = sctx->cur_inode_mode; + rdev = sctx->cur_inode_rdev; + } + + if (S_ISREG(mode)) { + cmd = BTRFS_SEND_C_MKFILE; + } else if (S_ISDIR(mode)) { + cmd = BTRFS_SEND_C_MKDIR; + } else if (S_ISLNK(mode)) { + cmd = BTRFS_SEND_C_SYMLINK; + } else if (S_ISCHR(mode) || S_ISBLK(mode)) { + cmd = BTRFS_SEND_C_MKNOD; + } else if (S_ISFIFO(mode)) { + cmd = BTRFS_SEND_C_MKFIFO; + } else if (S_ISSOCK(mode)) { + cmd = BTRFS_SEND_C_MKSOCK; + } else { + btrfs_warn(sctx->send_root->fs_info, "unexpected inode type %o", + (int)(mode & S_IFMT)); + ret = -EOPNOTSUPP; + goto out; + } + + ret = begin_cmd(sctx, cmd); + if (ret < 0) + goto out; + + ret = gen_unique_name(sctx, ino, gen, p); + if (ret < 0) + goto out; + + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); + TLV_PUT_U64(sctx, BTRFS_SEND_A_INO, ino); + + if (S_ISLNK(mode)) { + fs_path_reset(p); + ret = read_symlink(sctx->send_root, ino, p); + if (ret < 0) + goto out; + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, p); + } else if (S_ISCHR(mode) || S_ISBLK(mode) || + S_ISFIFO(mode) || S_ISSOCK(mode)) { + TLV_PUT_U64(sctx, BTRFS_SEND_A_RDEV, new_encode_dev(rdev)); + TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode); + } + + ret = send_cmd(sctx); + if (ret < 0) + goto out; + + +tlv_put_failure: +out: + fs_path_free(p); + return ret; +} + +/* + * We need some special handling for inodes that get processed before the parent + * directory got created. See process_recorded_refs for details. + * This function does the check if we already created the dir out of order. + */ +static int did_create_dir(struct send_ctx *sctx, u64 dir) +{ + int ret = 0; + int iter_ret = 0; + struct btrfs_path *path = NULL; + struct btrfs_key key; + struct btrfs_key found_key; + struct btrfs_key di_key; + struct btrfs_dir_item *di; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + key.objectid = dir; + key.type = BTRFS_DIR_INDEX_KEY; + key.offset = 0; + + btrfs_for_each_slot(sctx->send_root, &key, &found_key, path, iter_ret) { + struct extent_buffer *eb = path->nodes[0]; + + if (found_key.objectid != key.objectid || + found_key.type != key.type) { + ret = 0; + break; + } + + di = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dir_item); + btrfs_dir_item_key_to_cpu(eb, di, &di_key); + + if (di_key.type != BTRFS_ROOT_ITEM_KEY && + di_key.objectid < sctx->send_progress) { + ret = 1; + break; + } + } + /* Catch error found during iteration */ + if (iter_ret < 0) + ret = iter_ret; + + btrfs_free_path(path); + return ret; +} + +/* + * Only creates the inode if it is: + * 1. Not a directory + * 2. Or a directory which was not created already due to out of order + * directories. See did_create_dir and process_recorded_refs for details. + */ +static int send_create_inode_if_needed(struct send_ctx *sctx) +{ + int ret; + + if (S_ISDIR(sctx->cur_inode_mode)) { + ret = did_create_dir(sctx, sctx->cur_ino); + if (ret < 0) + return ret; + else if (ret > 0) + return 0; + } + + return send_create_inode(sctx, sctx->cur_ino); +} + +struct recorded_ref { + struct list_head list; + char *name; + struct fs_path *full_path; + u64 dir; + u64 dir_gen; + int name_len; + struct rb_node node; + struct rb_root *root; +}; + +static struct recorded_ref *recorded_ref_alloc(void) +{ + struct recorded_ref *ref; + + ref = kzalloc(sizeof(*ref), GFP_KERNEL); + if (!ref) + return NULL; + RB_CLEAR_NODE(&ref->node); + INIT_LIST_HEAD(&ref->list); + return ref; +} + +static void recorded_ref_free(struct recorded_ref *ref) +{ + if (!ref) + return; + if (!RB_EMPTY_NODE(&ref->node)) + rb_erase(&ref->node, ref->root); + list_del(&ref->list); + fs_path_free(ref->full_path); + kfree(ref); +} + +static void set_ref_path(struct recorded_ref *ref, struct fs_path *path) +{ + ref->full_path = path; + ref->name = (char *)kbasename(ref->full_path->start); + ref->name_len = ref->full_path->end - ref->name; +} + +static int dup_ref(struct recorded_ref *ref, struct list_head *list) +{ + struct recorded_ref *new; + + new = recorded_ref_alloc(); + if (!new) + return -ENOMEM; + + new->dir = ref->dir; + new->dir_gen = ref->dir_gen; + list_add_tail(&new->list, list); + return 0; +} + +static void __free_recorded_refs(struct list_head *head) +{ + struct recorded_ref *cur; + + while (!list_empty(head)) { + cur = list_entry(head->next, struct recorded_ref, list); + recorded_ref_free(cur); + } +} + +static void free_recorded_refs(struct send_ctx *sctx) +{ + __free_recorded_refs(&sctx->new_refs); + __free_recorded_refs(&sctx->deleted_refs); +} + +/* + * Renames/moves a file/dir to its orphan name. Used when the first + * ref of an unprocessed inode gets overwritten and for all non empty + * directories. + */ +static int orphanize_inode(struct send_ctx *sctx, u64 ino, u64 gen, + struct fs_path *path) +{ + int ret; + struct fs_path *orphan; + + orphan = fs_path_alloc(); + if (!orphan) + return -ENOMEM; + + ret = gen_unique_name(sctx, ino, gen, orphan); + if (ret < 0) + goto out; + + ret = send_rename(sctx, path, orphan); + +out: + fs_path_free(orphan); + return ret; +} + +static struct orphan_dir_info *add_orphan_dir_info(struct send_ctx *sctx, + u64 dir_ino, u64 dir_gen) +{ + struct rb_node **p = &sctx->orphan_dirs.rb_node; + struct rb_node *parent = NULL; + struct orphan_dir_info *entry, *odi; + + while (*p) { + parent = *p; + entry = rb_entry(parent, struct orphan_dir_info, node); + if (dir_ino < entry->ino) + p = &(*p)->rb_left; + else if (dir_ino > entry->ino) + p = &(*p)->rb_right; + else if (dir_gen < entry->gen) + p = &(*p)->rb_left; + else if (dir_gen > entry->gen) + p = &(*p)->rb_right; + else + return entry; + } + + odi = kmalloc(sizeof(*odi), GFP_KERNEL); + if (!odi) + return ERR_PTR(-ENOMEM); + odi->ino = dir_ino; + odi->gen = dir_gen; + odi->last_dir_index_offset = 0; + + rb_link_node(&odi->node, parent, p); + rb_insert_color(&odi->node, &sctx->orphan_dirs); + return odi; +} + +static struct orphan_dir_info *get_orphan_dir_info(struct send_ctx *sctx, + u64 dir_ino, u64 gen) +{ + struct rb_node *n = sctx->orphan_dirs.rb_node; + struct orphan_dir_info *entry; + + while (n) { + entry = rb_entry(n, struct orphan_dir_info, node); + if (dir_ino < entry->ino) + n = n->rb_left; + else if (dir_ino > entry->ino) + n = n->rb_right; + else if (gen < entry->gen) + n = n->rb_left; + else if (gen > entry->gen) + n = n->rb_right; + else + return entry; + } + return NULL; +} + +static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen) +{ + struct orphan_dir_info *odi = get_orphan_dir_info(sctx, dir_ino, gen); + + return odi != NULL; +} + +static void free_orphan_dir_info(struct send_ctx *sctx, + struct orphan_dir_info *odi) +{ + if (!odi) + return; + rb_erase(&odi->node, &sctx->orphan_dirs); + kfree(odi); +} + +/* + * Returns 1 if a directory can be removed at this point in time. + * We check this by iterating all dir items and checking if the inode behind + * the dir item was already processed. + */ +static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen, + u64 send_progress) +{ + int ret = 0; + int iter_ret = 0; + struct btrfs_root *root = sctx->parent_root; + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_key found_key; + struct btrfs_key loc; + struct btrfs_dir_item *di; + struct orphan_dir_info *odi = NULL; + + /* + * Don't try to rmdir the top/root subvolume dir. + */ + if (dir == BTRFS_FIRST_FREE_OBJECTID) + return 0; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + key.objectid = dir; + key.type = BTRFS_DIR_INDEX_KEY; + key.offset = 0; + + odi = get_orphan_dir_info(sctx, dir, dir_gen); + if (odi) + key.offset = odi->last_dir_index_offset; + + btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) { + struct waiting_dir_move *dm; + + if (found_key.objectid != key.objectid || + found_key.type != key.type) + break; + + di = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_dir_item); + btrfs_dir_item_key_to_cpu(path->nodes[0], di, &loc); + + dm = get_waiting_dir_move(sctx, loc.objectid); + if (dm) { + odi = add_orphan_dir_info(sctx, dir, dir_gen); + if (IS_ERR(odi)) { + ret = PTR_ERR(odi); + goto out; + } + odi->gen = dir_gen; + odi->last_dir_index_offset = found_key.offset; + dm->rmdir_ino = dir; + dm->rmdir_gen = dir_gen; + ret = 0; + goto out; + } + + if (loc.objectid > send_progress) { + odi = add_orphan_dir_info(sctx, dir, dir_gen); + if (IS_ERR(odi)) { + ret = PTR_ERR(odi); + goto out; + } + odi->gen = dir_gen; + odi->last_dir_index_offset = found_key.offset; + ret = 0; + goto out; + } + } + if (iter_ret < 0) { + ret = iter_ret; + goto out; + } + free_orphan_dir_info(sctx, odi); + + ret = 1; + +out: + btrfs_free_path(path); + return ret; +} + +static int is_waiting_for_move(struct send_ctx *sctx, u64 ino) +{ + struct waiting_dir_move *entry = get_waiting_dir_move(sctx, ino); + + return entry != NULL; +} + +static int add_waiting_dir_move(struct send_ctx *sctx, u64 ino, bool orphanized) +{ + struct rb_node **p = &sctx->waiting_dir_moves.rb_node; + struct rb_node *parent = NULL; + struct waiting_dir_move *entry, *dm; + + dm = kmalloc(sizeof(*dm), GFP_KERNEL); + if (!dm) + return -ENOMEM; + dm->ino = ino; + dm->rmdir_ino = 0; + dm->rmdir_gen = 0; + dm->orphanized = orphanized; + + while (*p) { + parent = *p; + entry = rb_entry(parent, struct waiting_dir_move, node); + if (ino < entry->ino) { + p = &(*p)->rb_left; + } else if (ino > entry->ino) { + p = &(*p)->rb_right; + } else { + kfree(dm); + return -EEXIST; + } + } + + rb_link_node(&dm->node, parent, p); + rb_insert_color(&dm->node, &sctx->waiting_dir_moves); + return 0; +} + +static struct waiting_dir_move * +get_waiting_dir_move(struct send_ctx *sctx, u64 ino) +{ + struct rb_node *n = sctx->waiting_dir_moves.rb_node; + struct waiting_dir_move *entry; + + while (n) { + entry = rb_entry(n, struct waiting_dir_move, node); + if (ino < entry->ino) + n = n->rb_left; + else if (ino > entry->ino) + n = n->rb_right; + else + return entry; + } + return NULL; +} + +static void free_waiting_dir_move(struct send_ctx *sctx, + struct waiting_dir_move *dm) +{ + if (!dm) + return; + rb_erase(&dm->node, &sctx->waiting_dir_moves); + kfree(dm); +} + +static int add_pending_dir_move(struct send_ctx *sctx, + u64 ino, + u64 ino_gen, + u64 parent_ino, + struct list_head *new_refs, + struct list_head *deleted_refs, + const bool is_orphan) +{ + struct rb_node **p = &sctx->pending_dir_moves.rb_node; + struct rb_node *parent = NULL; + struct pending_dir_move *entry = NULL, *pm; + struct recorded_ref *cur; + int exists = 0; + int ret; + + pm = kmalloc(sizeof(*pm), GFP_KERNEL); + if (!pm) + return -ENOMEM; + pm->parent_ino = parent_ino; + pm->ino = ino; + pm->gen = ino_gen; + INIT_LIST_HEAD(&pm->list); + INIT_LIST_HEAD(&pm->update_refs); + RB_CLEAR_NODE(&pm->node); + + while (*p) { + parent = *p; + entry = rb_entry(parent, struct pending_dir_move, node); + if (parent_ino < entry->parent_ino) { + p = &(*p)->rb_left; + } else if (parent_ino > entry->parent_ino) { + p = &(*p)->rb_right; + } else { + exists = 1; + break; + } + } + + list_for_each_entry(cur, deleted_refs, list) { + ret = dup_ref(cur, &pm->update_refs); + if (ret < 0) + goto out; + } + list_for_each_entry(cur, new_refs, list) { + ret = dup_ref(cur, &pm->update_refs); + if (ret < 0) + goto out; + } + + ret = add_waiting_dir_move(sctx, pm->ino, is_orphan); + if (ret) + goto out; + + if (exists) { + list_add_tail(&pm->list, &entry->list); + } else { + rb_link_node(&pm->node, parent, p); + rb_insert_color(&pm->node, &sctx->pending_dir_moves); + } + ret = 0; +out: + if (ret) { + __free_recorded_refs(&pm->update_refs); + kfree(pm); + } + return ret; +} + +static struct pending_dir_move *get_pending_dir_moves(struct send_ctx *sctx, + u64 parent_ino) +{ + struct rb_node *n = sctx->pending_dir_moves.rb_node; + struct pending_dir_move *entry; + + while (n) { + entry = rb_entry(n, struct pending_dir_move, node); + if (parent_ino < entry->parent_ino) + n = n->rb_left; + else if (parent_ino > entry->parent_ino) + n = n->rb_right; + else + return entry; + } + return NULL; +} + +static int path_loop(struct send_ctx *sctx, struct fs_path *name, + u64 ino, u64 gen, u64 *ancestor_ino) +{ + int ret = 0; + u64 parent_inode = 0; + u64 parent_gen = 0; + u64 start_ino = ino; + + *ancestor_ino = 0; + while (ino != BTRFS_FIRST_FREE_OBJECTID) { + fs_path_reset(name); + + if (is_waiting_for_rm(sctx, ino, gen)) + break; + if (is_waiting_for_move(sctx, ino)) { + if (*ancestor_ino == 0) + *ancestor_ino = ino; + ret = get_first_ref(sctx->parent_root, ino, + &parent_inode, &parent_gen, name); + } else { + ret = __get_cur_name_and_parent(sctx, ino, gen, + &parent_inode, + &parent_gen, name); + if (ret > 0) { + ret = 0; + break; + } + } + if (ret < 0) + break; + if (parent_inode == start_ino) { + ret = 1; + if (*ancestor_ino == 0) + *ancestor_ino = ino; + break; + } + ino = parent_inode; + gen = parent_gen; + } + return ret; +} + +static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm) +{ + struct fs_path *from_path = NULL; + struct fs_path *to_path = NULL; + struct fs_path *name = NULL; + u64 orig_progress = sctx->send_progress; + struct recorded_ref *cur; + u64 parent_ino, parent_gen; + struct waiting_dir_move *dm = NULL; + u64 rmdir_ino = 0; + u64 rmdir_gen; + u64 ancestor; + bool is_orphan; + int ret; + + name = fs_path_alloc(); + from_path = fs_path_alloc(); + if (!name || !from_path) { + ret = -ENOMEM; + goto out; + } + + dm = get_waiting_dir_move(sctx, pm->ino); + ASSERT(dm); + rmdir_ino = dm->rmdir_ino; + rmdir_gen = dm->rmdir_gen; + is_orphan = dm->orphanized; + free_waiting_dir_move(sctx, dm); + + if (is_orphan) { + ret = gen_unique_name(sctx, pm->ino, + pm->gen, from_path); + } else { + ret = get_first_ref(sctx->parent_root, pm->ino, + &parent_ino, &parent_gen, name); + if (ret < 0) + goto out; + ret = get_cur_path(sctx, parent_ino, parent_gen, + from_path); + if (ret < 0) + goto out; + ret = fs_path_add_path(from_path, name); + } + if (ret < 0) + goto out; + + sctx->send_progress = sctx->cur_ino + 1; + ret = path_loop(sctx, name, pm->ino, pm->gen, &ancestor); + if (ret < 0) + goto out; + if (ret) { + LIST_HEAD(deleted_refs); + ASSERT(ancestor > BTRFS_FIRST_FREE_OBJECTID); + ret = add_pending_dir_move(sctx, pm->ino, pm->gen, ancestor, + &pm->update_refs, &deleted_refs, + is_orphan); + if (ret < 0) + goto out; + if (rmdir_ino) { + dm = get_waiting_dir_move(sctx, pm->ino); + ASSERT(dm); + dm->rmdir_ino = rmdir_ino; + dm->rmdir_gen = rmdir_gen; + } + goto out; + } + fs_path_reset(name); + to_path = name; + name = NULL; + ret = get_cur_path(sctx, pm->ino, pm->gen, to_path); + if (ret < 0) + goto out; + + ret = send_rename(sctx, from_path, to_path); + if (ret < 0) + goto out; + + if (rmdir_ino) { + struct orphan_dir_info *odi; + u64 gen; + + odi = get_orphan_dir_info(sctx, rmdir_ino, rmdir_gen); + if (!odi) { + /* already deleted */ + goto finish; + } + gen = odi->gen; + + ret = can_rmdir(sctx, rmdir_ino, gen, sctx->cur_ino); + if (ret < 0) + goto out; + if (!ret) + goto finish; + + name = fs_path_alloc(); + if (!name) { + ret = -ENOMEM; + goto out; + } + ret = get_cur_path(sctx, rmdir_ino, gen, name); + if (ret < 0) + goto out; + ret = send_rmdir(sctx, name); + if (ret < 0) + goto out; + } + +finish: + ret = send_utimes(sctx, pm->ino, pm->gen); + if (ret < 0) + goto out; + + /* + * After rename/move, need to update the utimes of both new parent(s) + * and old parent(s). + */ + list_for_each_entry(cur, &pm->update_refs, list) { + /* + * The parent inode might have been deleted in the send snapshot + */ + ret = get_inode_info(sctx->send_root, cur->dir, NULL); + if (ret == -ENOENT) { + ret = 0; + continue; + } + if (ret < 0) + goto out; + + ret = send_utimes(sctx, cur->dir, cur->dir_gen); + if (ret < 0) + goto out; + } + +out: + fs_path_free(name); + fs_path_free(from_path); + fs_path_free(to_path); + sctx->send_progress = orig_progress; + + return ret; +} + +static void free_pending_move(struct send_ctx *sctx, struct pending_dir_move *m) +{ + if (!list_empty(&m->list)) + list_del(&m->list); + if (!RB_EMPTY_NODE(&m->node)) + rb_erase(&m->node, &sctx->pending_dir_moves); + __free_recorded_refs(&m->update_refs); + kfree(m); +} + +static void tail_append_pending_moves(struct send_ctx *sctx, + struct pending_dir_move *moves, + struct list_head *stack) +{ + if (list_empty(&moves->list)) { + list_add_tail(&moves->list, stack); + } else { + LIST_HEAD(list); + list_splice_init(&moves->list, &list); + list_add_tail(&moves->list, stack); + list_splice_tail(&list, stack); + } + if (!RB_EMPTY_NODE(&moves->node)) { + rb_erase(&moves->node, &sctx->pending_dir_moves); + RB_CLEAR_NODE(&moves->node); + } +} + +static int apply_children_dir_moves(struct send_ctx *sctx) +{ + struct pending_dir_move *pm; + struct list_head stack; + u64 parent_ino = sctx->cur_ino; + int ret = 0; + + pm = get_pending_dir_moves(sctx, parent_ino); + if (!pm) + return 0; + + INIT_LIST_HEAD(&stack); + tail_append_pending_moves(sctx, pm, &stack); + + while (!list_empty(&stack)) { + pm = list_first_entry(&stack, struct pending_dir_move, list); + parent_ino = pm->ino; + ret = apply_dir_move(sctx, pm); + free_pending_move(sctx, pm); + if (ret) + goto out; + pm = get_pending_dir_moves(sctx, parent_ino); + if (pm) + tail_append_pending_moves(sctx, pm, &stack); + } + return 0; + +out: + while (!list_empty(&stack)) { + pm = list_first_entry(&stack, struct pending_dir_move, list); + free_pending_move(sctx, pm); + } + return ret; +} + +/* + * We might need to delay a directory rename even when no ancestor directory + * (in the send root) with a higher inode number than ours (sctx->cur_ino) was + * renamed. This happens when we rename a directory to the old name (the name + * in the parent root) of some other unrelated directory that got its rename + * delayed due to some ancestor with higher number that got renamed. + * + * Example: + * + * Parent snapshot: + * . (ino 256) + * |---- a/ (ino 257) + * | |---- file (ino 260) + * | + * |---- b/ (ino 258) + * |---- c/ (ino 259) + * + * Send snapshot: + * . (ino 256) + * |---- a/ (ino 258) + * |---- x/ (ino 259) + * |---- y/ (ino 257) + * |----- file (ino 260) + * + * Here we can not rename 258 from 'b' to 'a' without the rename of inode 257 + * from 'a' to 'x/y' happening first, which in turn depends on the rename of + * inode 259 from 'c' to 'x'. So the order of rename commands the send stream + * must issue is: + * + * 1 - rename 259 from 'c' to 'x' + * 2 - rename 257 from 'a' to 'x/y' + * 3 - rename 258 from 'b' to 'a' + * + * Returns 1 if the rename of sctx->cur_ino needs to be delayed, 0 if it can + * be done right away and < 0 on error. + */ +static int wait_for_dest_dir_move(struct send_ctx *sctx, + struct recorded_ref *parent_ref, + const bool is_orphan) +{ + struct btrfs_fs_info *fs_info = sctx->parent_root->fs_info; + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_key di_key; + struct btrfs_dir_item *di; + u64 left_gen; + u64 right_gen; + int ret = 0; + struct waiting_dir_move *wdm; + + if (RB_EMPTY_ROOT(&sctx->waiting_dir_moves)) + return 0; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + key.objectid = parent_ref->dir; + key.type = BTRFS_DIR_ITEM_KEY; + key.offset = btrfs_name_hash(parent_ref->name, parent_ref->name_len); + + ret = btrfs_search_slot(NULL, sctx->parent_root, &key, path, 0, 0); + if (ret < 0) { + goto out; + } else if (ret > 0) { + ret = 0; + goto out; + } + + di = btrfs_match_dir_item_name(fs_info, path, parent_ref->name, + parent_ref->name_len); + if (!di) { + ret = 0; + goto out; + } + /* + * di_key.objectid has the number of the inode that has a dentry in the + * parent directory with the same name that sctx->cur_ino is being + * renamed to. We need to check if that inode is in the send root as + * well and if it is currently marked as an inode with a pending rename, + * if it is, we need to delay the rename of sctx->cur_ino as well, so + * that it happens after that other inode is renamed. + */ + btrfs_dir_item_key_to_cpu(path->nodes[0], di, &di_key); + if (di_key.type != BTRFS_INODE_ITEM_KEY) { + ret = 0; + goto out; + } + + ret = get_inode_gen(sctx->parent_root, di_key.objectid, &left_gen); + if (ret < 0) + goto out; + ret = get_inode_gen(sctx->send_root, di_key.objectid, &right_gen); + if (ret < 0) { + if (ret == -ENOENT) + ret = 0; + goto out; + } + + /* Different inode, no need to delay the rename of sctx->cur_ino */ + if (right_gen != left_gen) { + ret = 0; + goto out; + } + + wdm = get_waiting_dir_move(sctx, di_key.objectid); + if (wdm && !wdm->orphanized) { + ret = add_pending_dir_move(sctx, + sctx->cur_ino, + sctx->cur_inode_gen, + di_key.objectid, + &sctx->new_refs, + &sctx->deleted_refs, + is_orphan); + if (!ret) + ret = 1; + } +out: + btrfs_free_path(path); + return ret; +} + +/* + * Check if inode ino2, or any of its ancestors, is inode ino1. + * Return 1 if true, 0 if false and < 0 on error. + */ +static int check_ino_in_path(struct btrfs_root *root, + const u64 ino1, + const u64 ino1_gen, + const u64 ino2, + const u64 ino2_gen, + struct fs_path *fs_path) +{ + u64 ino = ino2; + + if (ino1 == ino2) + return ino1_gen == ino2_gen; + + while (ino > BTRFS_FIRST_FREE_OBJECTID) { + u64 parent; + u64 parent_gen; + int ret; + + fs_path_reset(fs_path); + ret = get_first_ref(root, ino, &parent, &parent_gen, fs_path); + if (ret < 0) + return ret; + if (parent == ino1) + return parent_gen == ino1_gen; + ino = parent; + } + return 0; +} + +/* + * Check if inode ino1 is an ancestor of inode ino2 in the given root for any + * possible path (in case ino2 is not a directory and has multiple hard links). + * Return 1 if true, 0 if false and < 0 on error. + */ +static int is_ancestor(struct btrfs_root *root, + const u64 ino1, + const u64 ino1_gen, + const u64 ino2, + struct fs_path *fs_path) +{ + bool free_fs_path = false; + int ret = 0; + int iter_ret = 0; + struct btrfs_path *path = NULL; + struct btrfs_key key; + + if (!fs_path) { + fs_path = fs_path_alloc(); + if (!fs_path) + return -ENOMEM; + free_fs_path = true; + } + + path = alloc_path_for_send(); + if (!path) { + ret = -ENOMEM; + goto out; + } + + key.objectid = ino2; + key.type = BTRFS_INODE_REF_KEY; + key.offset = 0; + + btrfs_for_each_slot(root, &key, &key, path, iter_ret) { + struct extent_buffer *leaf = path->nodes[0]; + int slot = path->slots[0]; + u32 cur_offset = 0; + u32 item_size; + + if (key.objectid != ino2) + break; + if (key.type != BTRFS_INODE_REF_KEY && + key.type != BTRFS_INODE_EXTREF_KEY) + break; + + item_size = btrfs_item_size(leaf, slot); + while (cur_offset < item_size) { + u64 parent; + u64 parent_gen; + + if (key.type == BTRFS_INODE_EXTREF_KEY) { + unsigned long ptr; + struct btrfs_inode_extref *extref; + + ptr = btrfs_item_ptr_offset(leaf, slot); + extref = (struct btrfs_inode_extref *) + (ptr + cur_offset); + parent = btrfs_inode_extref_parent(leaf, + extref); + cur_offset += sizeof(*extref); + cur_offset += btrfs_inode_extref_name_len(leaf, + extref); + } else { + parent = key.offset; + cur_offset = item_size; + } + + ret = get_inode_gen(root, parent, &parent_gen); + if (ret < 0) + goto out; + ret = check_ino_in_path(root, ino1, ino1_gen, + parent, parent_gen, fs_path); + if (ret) + goto out; + } + } + ret = 0; + if (iter_ret < 0) + ret = iter_ret; + +out: + btrfs_free_path(path); + if (free_fs_path) + fs_path_free(fs_path); + return ret; +} + +static int wait_for_parent_move(struct send_ctx *sctx, + struct recorded_ref *parent_ref, + const bool is_orphan) +{ + int ret = 0; + u64 ino = parent_ref->dir; + u64 ino_gen = parent_ref->dir_gen; + u64 parent_ino_before, parent_ino_after; + struct fs_path *path_before = NULL; + struct fs_path *path_after = NULL; + int len1, len2; + + path_after = fs_path_alloc(); + path_before = fs_path_alloc(); + if (!path_after || !path_before) { + ret = -ENOMEM; + goto out; + } + + /* + * Our current directory inode may not yet be renamed/moved because some + * ancestor (immediate or not) has to be renamed/moved first. So find if + * such ancestor exists and make sure our own rename/move happens after + * that ancestor is processed to avoid path build infinite loops (done + * at get_cur_path()). + */ + while (ino > BTRFS_FIRST_FREE_OBJECTID) { + u64 parent_ino_after_gen; + + if (is_waiting_for_move(sctx, ino)) { + /* + * If the current inode is an ancestor of ino in the + * parent root, we need to delay the rename of the + * current inode, otherwise don't delayed the rename + * because we can end up with a circular dependency + * of renames, resulting in some directories never + * getting the respective rename operations issued in + * the send stream or getting into infinite path build + * loops. + */ + ret = is_ancestor(sctx->parent_root, + sctx->cur_ino, sctx->cur_inode_gen, + ino, path_before); + if (ret) + break; + } + + fs_path_reset(path_before); + fs_path_reset(path_after); + + ret = get_first_ref(sctx->send_root, ino, &parent_ino_after, + &parent_ino_after_gen, path_after); + if (ret < 0) + goto out; + ret = get_first_ref(sctx->parent_root, ino, &parent_ino_before, + NULL, path_before); + if (ret < 0 && ret != -ENOENT) { + goto out; + } else if (ret == -ENOENT) { + ret = 0; + break; + } + + len1 = fs_path_len(path_before); + len2 = fs_path_len(path_after); + if (ino > sctx->cur_ino && + (parent_ino_before != parent_ino_after || len1 != len2 || + memcmp(path_before->start, path_after->start, len1))) { + u64 parent_ino_gen; + + ret = get_inode_gen(sctx->parent_root, ino, &parent_ino_gen); + if (ret < 0) + goto out; + if (ino_gen == parent_ino_gen) { + ret = 1; + break; + } + } + ino = parent_ino_after; + ino_gen = parent_ino_after_gen; + } + +out: + fs_path_free(path_before); + fs_path_free(path_after); + + if (ret == 1) { + ret = add_pending_dir_move(sctx, + sctx->cur_ino, + sctx->cur_inode_gen, + ino, + &sctx->new_refs, + &sctx->deleted_refs, + is_orphan); + if (!ret) + ret = 1; + } + + return ret; +} + +static int update_ref_path(struct send_ctx *sctx, struct recorded_ref *ref) +{ + int ret; + struct fs_path *new_path; + + /* + * Our reference's name member points to its full_path member string, so + * we use here a new path. + */ + new_path = fs_path_alloc(); + if (!new_path) + return -ENOMEM; + + ret = get_cur_path(sctx, ref->dir, ref->dir_gen, new_path); + if (ret < 0) { + fs_path_free(new_path); + return ret; + } + ret = fs_path_add(new_path, ref->name, ref->name_len); + if (ret < 0) { + fs_path_free(new_path); + return ret; + } + + fs_path_free(ref->full_path); + set_ref_path(ref, new_path); + + return 0; +} + +/* + * When processing the new references for an inode we may orphanize an existing + * directory inode because its old name conflicts with one of the new references + * of the current inode. Later, when processing another new reference of our + * inode, we might need to orphanize another inode, but the path we have in the + * reference reflects the pre-orphanization name of the directory we previously + * orphanized. For example: + * + * parent snapshot looks like: + * + * . (ino 256) + * |----- f1 (ino 257) + * |----- f2 (ino 258) + * |----- d1/ (ino 259) + * |----- d2/ (ino 260) + * + * send snapshot looks like: + * + * . (ino 256) + * |----- d1 (ino 258) + * |----- f2/ (ino 259) + * |----- f2_link/ (ino 260) + * | |----- f1 (ino 257) + * | + * |----- d2 (ino 258) + * + * When processing inode 257 we compute the name for inode 259 as "d1", and we + * cache it in the name cache. Later when we start processing inode 258, when + * collecting all its new references we set a full path of "d1/d2" for its new + * reference with name "d2". When we start processing the new references we + * start by processing the new reference with name "d1", and this results in + * orphanizing inode 259, since its old reference causes a conflict. Then we + * move on the next new reference, with name "d2", and we find out we must + * orphanize inode 260, as its old reference conflicts with ours - but for the + * orphanization we use a source path corresponding to the path we stored in the + * new reference, which is "d1/d2" and not "o259-6-0/d2" - this makes the + * receiver fail since the path component "d1/" no longer exists, it was renamed + * to "o259-6-0/" when processing the previous new reference. So in this case we + * must recompute the path in the new reference and use it for the new + * orphanization operation. + */ +static int refresh_ref_path(struct send_ctx *sctx, struct recorded_ref *ref) +{ + char *name; + int ret; + + name = kmemdup(ref->name, ref->name_len, GFP_KERNEL); + if (!name) + return -ENOMEM; + + fs_path_reset(ref->full_path); + ret = get_cur_path(sctx, ref->dir, ref->dir_gen, ref->full_path); + if (ret < 0) + goto out; + + ret = fs_path_add(ref->full_path, name, ref->name_len); + if (ret < 0) + goto out; + + /* Update the reference's base name pointer. */ + set_ref_path(ref, ref->full_path); +out: + kfree(name); + return ret; +} + +/* + * This does all the move/link/unlink/rmdir magic. + */ +static int process_recorded_refs(struct send_ctx *sctx, int *pending_move) +{ + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + int ret = 0; + struct recorded_ref *cur; + struct recorded_ref *cur2; + struct list_head check_dirs; + struct fs_path *valid_path = NULL; + u64 ow_inode = 0; + u64 ow_gen; + u64 ow_mode; + int did_overwrite = 0; + int is_orphan = 0; + u64 last_dir_ino_rm = 0; + bool can_rename = true; + bool orphanized_dir = false; + bool orphanized_ancestor = false; + + btrfs_debug(fs_info, "process_recorded_refs %llu", sctx->cur_ino); + + /* + * This should never happen as the root dir always has the same ref + * which is always '..' + */ + BUG_ON(sctx->cur_ino <= BTRFS_FIRST_FREE_OBJECTID); + INIT_LIST_HEAD(&check_dirs); + + valid_path = fs_path_alloc(); + if (!valid_path) { + ret = -ENOMEM; + goto out; + } + + /* + * First, check if the first ref of the current inode was overwritten + * before. If yes, we know that the current inode was already orphanized + * and thus use the orphan name. If not, we can use get_cur_path to + * get the path of the first ref as it would like while receiving at + * this point in time. + * New inodes are always orphan at the beginning, so force to use the + * orphan name in this case. + * The first ref is stored in valid_path and will be updated if it + * gets moved around. + */ + if (!sctx->cur_inode_new) { + ret = did_overwrite_first_ref(sctx, sctx->cur_ino, + sctx->cur_inode_gen); + if (ret < 0) + goto out; + if (ret) + did_overwrite = 1; + } + if (sctx->cur_inode_new || did_overwrite) { + ret = gen_unique_name(sctx, sctx->cur_ino, + sctx->cur_inode_gen, valid_path); + if (ret < 0) + goto out; + is_orphan = 1; + } else { + ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, + valid_path); + if (ret < 0) + goto out; + } + + /* + * Before doing any rename and link operations, do a first pass on the + * new references to orphanize any unprocessed inodes that may have a + * reference that conflicts with one of the new references of the current + * inode. This needs to happen first because a new reference may conflict + * with the old reference of a parent directory, so we must make sure + * that the path used for link and rename commands don't use an + * orphanized name when an ancestor was not yet orphanized. + * + * Example: + * + * Parent snapshot: + * + * . (ino 256) + * |----- testdir/ (ino 259) + * | |----- a (ino 257) + * | + * |----- b (ino 258) + * + * Send snapshot: + * + * . (ino 256) + * |----- testdir_2/ (ino 259) + * | |----- a (ino 260) + * | + * |----- testdir (ino 257) + * |----- b (ino 257) + * |----- b2 (ino 258) + * + * Processing the new reference for inode 257 with name "b" may happen + * before processing the new reference with name "testdir". If so, we + * must make sure that by the time we send a link command to create the + * hard link "b", inode 259 was already orphanized, since the generated + * path in "valid_path" already contains the orphanized name for 259. + * We are processing inode 257, so only later when processing 259 we do + * the rename operation to change its temporary (orphanized) name to + * "testdir_2". + */ + list_for_each_entry(cur, &sctx->new_refs, list) { + ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen); + if (ret < 0) + goto out; + if (ret == inode_state_will_create) + continue; + + /* + * Check if this new ref would overwrite the first ref of another + * unprocessed inode. If yes, orphanize the overwritten inode. + * If we find an overwritten ref that is not the first ref, + * simply unlink it. + */ + ret = will_overwrite_ref(sctx, cur->dir, cur->dir_gen, + cur->name, cur->name_len, + &ow_inode, &ow_gen, &ow_mode); + if (ret < 0) + goto out; + if (ret) { + ret = is_first_ref(sctx->parent_root, + ow_inode, cur->dir, cur->name, + cur->name_len); + if (ret < 0) + goto out; + if (ret) { + struct name_cache_entry *nce; + struct waiting_dir_move *wdm; + + if (orphanized_dir) { + ret = refresh_ref_path(sctx, cur); + if (ret < 0) + goto out; + } + + ret = orphanize_inode(sctx, ow_inode, ow_gen, + cur->full_path); + if (ret < 0) + goto out; + if (S_ISDIR(ow_mode)) + orphanized_dir = true; + + /* + * If ow_inode has its rename operation delayed + * make sure that its orphanized name is used in + * the source path when performing its rename + * operation. + */ + if (is_waiting_for_move(sctx, ow_inode)) { + wdm = get_waiting_dir_move(sctx, + ow_inode); + ASSERT(wdm); + wdm->orphanized = true; + } + + /* + * Make sure we clear our orphanized inode's + * name from the name cache. This is because the + * inode ow_inode might be an ancestor of some + * other inode that will be orphanized as well + * later and has an inode number greater than + * sctx->send_progress. We need to prevent + * future name lookups from using the old name + * and get instead the orphan name. + */ + nce = name_cache_search(sctx, ow_inode, ow_gen); + if (nce) { + name_cache_delete(sctx, nce); + kfree(nce); + } + + /* + * ow_inode might currently be an ancestor of + * cur_ino, therefore compute valid_path (the + * current path of cur_ino) again because it + * might contain the pre-orphanization name of + * ow_inode, which is no longer valid. + */ + ret = is_ancestor(sctx->parent_root, + ow_inode, ow_gen, + sctx->cur_ino, NULL); + if (ret > 0) { + orphanized_ancestor = true; + fs_path_reset(valid_path); + ret = get_cur_path(sctx, sctx->cur_ino, + sctx->cur_inode_gen, + valid_path); + } + if (ret < 0) + goto out; + } else { + /* + * If we previously orphanized a directory that + * collided with a new reference that we already + * processed, recompute the current path because + * that directory may be part of the path. + */ + if (orphanized_dir) { + ret = refresh_ref_path(sctx, cur); + if (ret < 0) + goto out; + } + ret = send_unlink(sctx, cur->full_path); + if (ret < 0) + goto out; + } + } + + } + + list_for_each_entry(cur, &sctx->new_refs, list) { + /* + * We may have refs where the parent directory does not exist + * yet. This happens if the parent directories inum is higher + * than the current inum. To handle this case, we create the + * parent directory out of order. But we need to check if this + * did already happen before due to other refs in the same dir. + */ + ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen); + if (ret < 0) + goto out; + if (ret == inode_state_will_create) { + ret = 0; + /* + * First check if any of the current inodes refs did + * already create the dir. + */ + list_for_each_entry(cur2, &sctx->new_refs, list) { + if (cur == cur2) + break; + if (cur2->dir == cur->dir) { + ret = 1; + break; + } + } + + /* + * If that did not happen, check if a previous inode + * did already create the dir. + */ + if (!ret) + ret = did_create_dir(sctx, cur->dir); + if (ret < 0) + goto out; + if (!ret) { + ret = send_create_inode(sctx, cur->dir); + if (ret < 0) + goto out; + } + } + + if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root) { + ret = wait_for_dest_dir_move(sctx, cur, is_orphan); + if (ret < 0) + goto out; + if (ret == 1) { + can_rename = false; + *pending_move = 1; + } + } + + if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root && + can_rename) { + ret = wait_for_parent_move(sctx, cur, is_orphan); + if (ret < 0) + goto out; + if (ret == 1) { + can_rename = false; + *pending_move = 1; + } + } + + /* + * link/move the ref to the new place. If we have an orphan + * inode, move it and update valid_path. If not, link or move + * it depending on the inode mode. + */ + if (is_orphan && can_rename) { + ret = send_rename(sctx, valid_path, cur->full_path); + if (ret < 0) + goto out; + is_orphan = 0; + ret = fs_path_copy(valid_path, cur->full_path); + if (ret < 0) + goto out; + } else if (can_rename) { + if (S_ISDIR(sctx->cur_inode_mode)) { + /* + * Dirs can't be linked, so move it. For moved + * dirs, we always have one new and one deleted + * ref. The deleted ref is ignored later. + */ + ret = send_rename(sctx, valid_path, + cur->full_path); + if (!ret) + ret = fs_path_copy(valid_path, + cur->full_path); + if (ret < 0) + goto out; + } else { + /* + * We might have previously orphanized an inode + * which is an ancestor of our current inode, + * so our reference's full path, which was + * computed before any such orphanizations, must + * be updated. + */ + if (orphanized_dir) { + ret = update_ref_path(sctx, cur); + if (ret < 0) + goto out; + } + ret = send_link(sctx, cur->full_path, + valid_path); + if (ret < 0) + goto out; + } + } + ret = dup_ref(cur, &check_dirs); + if (ret < 0) + goto out; + } + + if (S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_deleted) { + /* + * Check if we can already rmdir the directory. If not, + * orphanize it. For every dir item inside that gets deleted + * later, we do this check again and rmdir it then if possible. + * See the use of check_dirs for more details. + */ + ret = can_rmdir(sctx, sctx->cur_ino, sctx->cur_inode_gen, + sctx->cur_ino); + if (ret < 0) + goto out; + if (ret) { + ret = send_rmdir(sctx, valid_path); + if (ret < 0) + goto out; + } else if (!is_orphan) { + ret = orphanize_inode(sctx, sctx->cur_ino, + sctx->cur_inode_gen, valid_path); + if (ret < 0) + goto out; + is_orphan = 1; + } + + list_for_each_entry(cur, &sctx->deleted_refs, list) { + ret = dup_ref(cur, &check_dirs); + if (ret < 0) + goto out; + } + } else if (S_ISDIR(sctx->cur_inode_mode) && + !list_empty(&sctx->deleted_refs)) { + /* + * We have a moved dir. Add the old parent to check_dirs + */ + cur = list_entry(sctx->deleted_refs.next, struct recorded_ref, + list); + ret = dup_ref(cur, &check_dirs); + if (ret < 0) + goto out; + } else if (!S_ISDIR(sctx->cur_inode_mode)) { + /* + * We have a non dir inode. Go through all deleted refs and + * unlink them if they were not already overwritten by other + * inodes. + */ + list_for_each_entry(cur, &sctx->deleted_refs, list) { + ret = did_overwrite_ref(sctx, cur->dir, cur->dir_gen, + sctx->cur_ino, sctx->cur_inode_gen, + cur->name, cur->name_len); + if (ret < 0) + goto out; + if (!ret) { + /* + * If we orphanized any ancestor before, we need + * to recompute the full path for deleted names, + * since any such path was computed before we + * processed any references and orphanized any + * ancestor inode. + */ + if (orphanized_ancestor) { + ret = update_ref_path(sctx, cur); + if (ret < 0) + goto out; + } + ret = send_unlink(sctx, cur->full_path); + if (ret < 0) + goto out; + } + ret = dup_ref(cur, &check_dirs); + if (ret < 0) + goto out; + } + /* + * If the inode is still orphan, unlink the orphan. This may + * happen when a previous inode did overwrite the first ref + * of this inode and no new refs were added for the current + * inode. Unlinking does not mean that the inode is deleted in + * all cases. There may still be links to this inode in other + * places. + */ + if (is_orphan) { + ret = send_unlink(sctx, valid_path); + if (ret < 0) + goto out; + } + } + + /* + * We did collect all parent dirs where cur_inode was once located. We + * now go through all these dirs and check if they are pending for + * deletion and if it's finally possible to perform the rmdir now. + * We also update the inode stats of the parent dirs here. + */ + list_for_each_entry(cur, &check_dirs, list) { + /* + * In case we had refs into dirs that were not processed yet, + * we don't need to do the utime and rmdir logic for these dirs. + * The dir will be processed later. + */ + if (cur->dir > sctx->cur_ino) + continue; + + ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen); + if (ret < 0) + goto out; + + if (ret == inode_state_did_create || + ret == inode_state_no_change) { + /* TODO delayed utimes */ + ret = send_utimes(sctx, cur->dir, cur->dir_gen); + if (ret < 0) + goto out; + } else if (ret == inode_state_did_delete && + cur->dir != last_dir_ino_rm) { + ret = can_rmdir(sctx, cur->dir, cur->dir_gen, + sctx->cur_ino); + if (ret < 0) + goto out; + if (ret) { + ret = get_cur_path(sctx, cur->dir, + cur->dir_gen, valid_path); + if (ret < 0) + goto out; + ret = send_rmdir(sctx, valid_path); + if (ret < 0) + goto out; + last_dir_ino_rm = cur->dir; + } + } + } + + ret = 0; + +out: + __free_recorded_refs(&check_dirs); + free_recorded_refs(sctx); + fs_path_free(valid_path); + return ret; +} + +static int rbtree_ref_comp(const void *k, const struct rb_node *node) +{ + const struct recorded_ref *data = k; + const struct recorded_ref *ref = rb_entry(node, struct recorded_ref, node); + int result; + + if (data->dir > ref->dir) + return 1; + if (data->dir < ref->dir) + return -1; + if (data->dir_gen > ref->dir_gen) + return 1; + if (data->dir_gen < ref->dir_gen) + return -1; + if (data->name_len > ref->name_len) + return 1; + if (data->name_len < ref->name_len) + return -1; + result = strcmp(data->name, ref->name); + if (result > 0) + return 1; + if (result < 0) + return -1; + return 0; +} + +static bool rbtree_ref_less(struct rb_node *node, const struct rb_node *parent) +{ + const struct recorded_ref *entry = rb_entry(node, struct recorded_ref, node); + + return rbtree_ref_comp(entry, parent) < 0; +} + +static int record_ref_in_tree(struct rb_root *root, struct list_head *refs, + struct fs_path *name, u64 dir, u64 dir_gen, + struct send_ctx *sctx) +{ + int ret = 0; + struct fs_path *path = NULL; + struct recorded_ref *ref = NULL; + + path = fs_path_alloc(); + if (!path) { + ret = -ENOMEM; + goto out; + } + + ref = recorded_ref_alloc(); + if (!ref) { + ret = -ENOMEM; + goto out; + } + + ret = get_cur_path(sctx, dir, dir_gen, path); + if (ret < 0) + goto out; + ret = fs_path_add_path(path, name); + if (ret < 0) + goto out; + + ref->dir = dir; + ref->dir_gen = dir_gen; + set_ref_path(ref, path); + list_add_tail(&ref->list, refs); + rb_add(&ref->node, root, rbtree_ref_less); + ref->root = root; +out: + if (ret) { + if (path && (!ref || !ref->full_path)) + fs_path_free(path); + recorded_ref_free(ref); + } + return ret; +} + +static int record_new_ref_if_needed(int num, u64 dir, int index, + struct fs_path *name, void *ctx) +{ + int ret = 0; + struct send_ctx *sctx = ctx; + struct rb_node *node = NULL; + struct recorded_ref data; + struct recorded_ref *ref; + u64 dir_gen; + + ret = get_inode_gen(sctx->send_root, dir, &dir_gen); + if (ret < 0) + goto out; + + data.dir = dir; + data.dir_gen = dir_gen; + set_ref_path(&data, name); + node = rb_find(&data, &sctx->rbtree_deleted_refs, rbtree_ref_comp); + if (node) { + ref = rb_entry(node, struct recorded_ref, node); + recorded_ref_free(ref); + } else { + ret = record_ref_in_tree(&sctx->rbtree_new_refs, + &sctx->new_refs, name, dir, dir_gen, + sctx); + } +out: + return ret; +} + +static int record_deleted_ref_if_needed(int num, u64 dir, int index, + struct fs_path *name, void *ctx) +{ + int ret = 0; + struct send_ctx *sctx = ctx; + struct rb_node *node = NULL; + struct recorded_ref data; + struct recorded_ref *ref; + u64 dir_gen; + + ret = get_inode_gen(sctx->parent_root, dir, &dir_gen); + if (ret < 0) + goto out; + + data.dir = dir; + data.dir_gen = dir_gen; + set_ref_path(&data, name); + node = rb_find(&data, &sctx->rbtree_new_refs, rbtree_ref_comp); + if (node) { + ref = rb_entry(node, struct recorded_ref, node); + recorded_ref_free(ref); + } else { + ret = record_ref_in_tree(&sctx->rbtree_deleted_refs, + &sctx->deleted_refs, name, dir, + dir_gen, sctx); + } +out: + return ret; +} + +static int record_new_ref(struct send_ctx *sctx) +{ + int ret; + + ret = iterate_inode_ref(sctx->send_root, sctx->left_path, + sctx->cmp_key, 0, record_new_ref_if_needed, sctx); + if (ret < 0) + goto out; + ret = 0; + +out: + return ret; +} + +static int record_deleted_ref(struct send_ctx *sctx) +{ + int ret; + + ret = iterate_inode_ref(sctx->parent_root, sctx->right_path, + sctx->cmp_key, 0, record_deleted_ref_if_needed, + sctx); + if (ret < 0) + goto out; + ret = 0; + +out: + return ret; +} + +static int record_changed_ref(struct send_ctx *sctx) +{ + int ret = 0; + + ret = iterate_inode_ref(sctx->send_root, sctx->left_path, + sctx->cmp_key, 0, record_new_ref_if_needed, sctx); + if (ret < 0) + goto out; + ret = iterate_inode_ref(sctx->parent_root, sctx->right_path, + sctx->cmp_key, 0, record_deleted_ref_if_needed, sctx); + if (ret < 0) + goto out; + ret = 0; + +out: + return ret; +} + +/* + * Record and process all refs at once. Needed when an inode changes the + * generation number, which means that it was deleted and recreated. + */ +static int process_all_refs(struct send_ctx *sctx, + enum btrfs_compare_tree_result cmd) +{ + int ret = 0; + int iter_ret = 0; + struct btrfs_root *root; + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_key found_key; + iterate_inode_ref_t cb; + int pending_move = 0; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + if (cmd == BTRFS_COMPARE_TREE_NEW) { + root = sctx->send_root; + cb = record_new_ref_if_needed; + } else if (cmd == BTRFS_COMPARE_TREE_DELETED) { + root = sctx->parent_root; + cb = record_deleted_ref_if_needed; + } else { + btrfs_err(sctx->send_root->fs_info, + "Wrong command %d in process_all_refs", cmd); + ret = -EINVAL; + goto out; + } + + key.objectid = sctx->cmp_key->objectid; + key.type = BTRFS_INODE_REF_KEY; + key.offset = 0; + btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) { + if (found_key.objectid != key.objectid || + (found_key.type != BTRFS_INODE_REF_KEY && + found_key.type != BTRFS_INODE_EXTREF_KEY)) + break; + + ret = iterate_inode_ref(root, path, &found_key, 0, cb, sctx); + if (ret < 0) + goto out; + } + /* Catch error found during iteration */ + if (iter_ret < 0) { + ret = iter_ret; + goto out; + } + btrfs_release_path(path); + + /* + * We don't actually care about pending_move as we are simply + * re-creating this inode and will be rename'ing it into place once we + * rename the parent directory. + */ + ret = process_recorded_refs(sctx, &pending_move); +out: + btrfs_free_path(path); + return ret; +} + +static int send_set_xattr(struct send_ctx *sctx, + struct fs_path *path, + const char *name, int name_len, + const char *data, int data_len) +{ + int ret = 0; + + ret = begin_cmd(sctx, BTRFS_SEND_C_SET_XATTR); + if (ret < 0) + goto out; + + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); + TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len); + TLV_PUT(sctx, BTRFS_SEND_A_XATTR_DATA, data, data_len); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + return ret; +} + +static int send_remove_xattr(struct send_ctx *sctx, + struct fs_path *path, + const char *name, int name_len) +{ + int ret = 0; + + ret = begin_cmd(sctx, BTRFS_SEND_C_REMOVE_XATTR); + if (ret < 0) + goto out; + + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); + TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + return ret; +} + +static int __process_new_xattr(int num, struct btrfs_key *di_key, + const char *name, int name_len, const char *data, + int data_len, void *ctx) +{ + int ret; + struct send_ctx *sctx = ctx; + struct fs_path *p; + struct posix_acl_xattr_header dummy_acl; + + /* Capabilities are emitted by finish_inode_if_needed */ + if (!strncmp(name, XATTR_NAME_CAPS, name_len)) + return 0; + + p = fs_path_alloc(); + if (!p) + return -ENOMEM; + + /* + * This hack is needed because empty acls are stored as zero byte + * data in xattrs. Problem with that is, that receiving these zero byte + * acls will fail later. To fix this, we send a dummy acl list that + * only contains the version number and no entries. + */ + if (!strncmp(name, XATTR_NAME_POSIX_ACL_ACCESS, name_len) || + !strncmp(name, XATTR_NAME_POSIX_ACL_DEFAULT, name_len)) { + if (data_len == 0) { + dummy_acl.a_version = + cpu_to_le32(POSIX_ACL_XATTR_VERSION); + data = (char *)&dummy_acl; + data_len = sizeof(dummy_acl); + } + } + + ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); + if (ret < 0) + goto out; + + ret = send_set_xattr(sctx, p, name, name_len, data, data_len); + +out: + fs_path_free(p); + return ret; +} + +static int __process_deleted_xattr(int num, struct btrfs_key *di_key, + const char *name, int name_len, + const char *data, int data_len, void *ctx) +{ + int ret; + struct send_ctx *sctx = ctx; + struct fs_path *p; + + p = fs_path_alloc(); + if (!p) + return -ENOMEM; + + ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); + if (ret < 0) + goto out; + + ret = send_remove_xattr(sctx, p, name, name_len); + +out: + fs_path_free(p); + return ret; +} + +static int process_new_xattr(struct send_ctx *sctx) +{ + int ret = 0; + + ret = iterate_dir_item(sctx->send_root, sctx->left_path, + __process_new_xattr, sctx); + + return ret; +} + +static int process_deleted_xattr(struct send_ctx *sctx) +{ + return iterate_dir_item(sctx->parent_root, sctx->right_path, + __process_deleted_xattr, sctx); +} + +struct find_xattr_ctx { + const char *name; + int name_len; + int found_idx; + char *found_data; + int found_data_len; +}; + +static int __find_xattr(int num, struct btrfs_key *di_key, const char *name, + int name_len, const char *data, int data_len, void *vctx) +{ + struct find_xattr_ctx *ctx = vctx; + + if (name_len == ctx->name_len && + strncmp(name, ctx->name, name_len) == 0) { + ctx->found_idx = num; + ctx->found_data_len = data_len; + ctx->found_data = kmemdup(data, data_len, GFP_KERNEL); + if (!ctx->found_data) + return -ENOMEM; + return 1; + } + return 0; +} + +static int find_xattr(struct btrfs_root *root, + struct btrfs_path *path, + struct btrfs_key *key, + const char *name, int name_len, + char **data, int *data_len) +{ + int ret; + struct find_xattr_ctx ctx; + + ctx.name = name; + ctx.name_len = name_len; + ctx.found_idx = -1; + ctx.found_data = NULL; + ctx.found_data_len = 0; + + ret = iterate_dir_item(root, path, __find_xattr, &ctx); + if (ret < 0) + return ret; + + if (ctx.found_idx == -1) + return -ENOENT; + if (data) { + *data = ctx.found_data; + *data_len = ctx.found_data_len; + } else { + kfree(ctx.found_data); + } + return ctx.found_idx; +} + + +static int __process_changed_new_xattr(int num, struct btrfs_key *di_key, + const char *name, int name_len, + const char *data, int data_len, + void *ctx) +{ + int ret; + struct send_ctx *sctx = ctx; + char *found_data = NULL; + int found_data_len = 0; + + ret = find_xattr(sctx->parent_root, sctx->right_path, + sctx->cmp_key, name, name_len, &found_data, + &found_data_len); + if (ret == -ENOENT) { + ret = __process_new_xattr(num, di_key, name, name_len, data, + data_len, ctx); + } else if (ret >= 0) { + if (data_len != found_data_len || + memcmp(data, found_data, data_len)) { + ret = __process_new_xattr(num, di_key, name, name_len, + data, data_len, ctx); + } else { + ret = 0; + } + } + + kfree(found_data); + return ret; +} + +static int __process_changed_deleted_xattr(int num, struct btrfs_key *di_key, + const char *name, int name_len, + const char *data, int data_len, + void *ctx) +{ + int ret; + struct send_ctx *sctx = ctx; + + ret = find_xattr(sctx->send_root, sctx->left_path, sctx->cmp_key, + name, name_len, NULL, NULL); + if (ret == -ENOENT) + ret = __process_deleted_xattr(num, di_key, name, name_len, data, + data_len, ctx); + else if (ret >= 0) + ret = 0; + + return ret; +} + +static int process_changed_xattr(struct send_ctx *sctx) +{ + int ret = 0; + + ret = iterate_dir_item(sctx->send_root, sctx->left_path, + __process_changed_new_xattr, sctx); + if (ret < 0) + goto out; + ret = iterate_dir_item(sctx->parent_root, sctx->right_path, + __process_changed_deleted_xattr, sctx); + +out: + return ret; +} + +static int process_all_new_xattrs(struct send_ctx *sctx) +{ + int ret = 0; + int iter_ret = 0; + struct btrfs_root *root; + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_key found_key; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + root = sctx->send_root; + + key.objectid = sctx->cmp_key->objectid; + key.type = BTRFS_XATTR_ITEM_KEY; + key.offset = 0; + btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) { + if (found_key.objectid != key.objectid || + found_key.type != key.type) { + ret = 0; + break; + } + + ret = iterate_dir_item(root, path, __process_new_xattr, sctx); + if (ret < 0) + break; + } + /* Catch error found during iteration */ + if (iter_ret < 0) + ret = iter_ret; + + btrfs_free_path(path); + return ret; +} + +static int send_verity(struct send_ctx *sctx, struct fs_path *path, + struct fsverity_descriptor *desc) +{ + int ret; + + ret = begin_cmd(sctx, BTRFS_SEND_C_ENABLE_VERITY); + if (ret < 0) + goto out; + + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); + TLV_PUT_U8(sctx, BTRFS_SEND_A_VERITY_ALGORITHM, + le8_to_cpu(desc->hash_algorithm)); + TLV_PUT_U32(sctx, BTRFS_SEND_A_VERITY_BLOCK_SIZE, + 1U << le8_to_cpu(desc->log_blocksize)); + TLV_PUT(sctx, BTRFS_SEND_A_VERITY_SALT_DATA, desc->salt, + le8_to_cpu(desc->salt_size)); + TLV_PUT(sctx, BTRFS_SEND_A_VERITY_SIG_DATA, desc->signature, + le32_to_cpu(desc->sig_size)); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + return ret; +} + +static int process_verity(struct send_ctx *sctx) +{ + int ret = 0; + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + struct inode *inode; + struct fs_path *p; + + inode = btrfs_iget(fs_info->sb, sctx->cur_ino, sctx->send_root); + if (IS_ERR(inode)) + return PTR_ERR(inode); + + ret = btrfs_get_verity_descriptor(inode, NULL, 0); + if (ret < 0) + goto iput; + + if (ret > FS_VERITY_MAX_DESCRIPTOR_SIZE) { + ret = -EMSGSIZE; + goto iput; + } + if (!sctx->verity_descriptor) { + sctx->verity_descriptor = kvmalloc(FS_VERITY_MAX_DESCRIPTOR_SIZE, + GFP_KERNEL); + if (!sctx->verity_descriptor) { + ret = -ENOMEM; + goto iput; + } + } + + ret = btrfs_get_verity_descriptor(inode, sctx->verity_descriptor, ret); + if (ret < 0) + goto iput; + + p = fs_path_alloc(); + if (!p) { + ret = -ENOMEM; + goto iput; + } + ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); + if (ret < 0) + goto free_path; + + ret = send_verity(sctx, p, sctx->verity_descriptor); + if (ret < 0) + goto free_path; + +free_path: + fs_path_free(p); +iput: + iput(inode); + return ret; +} + +static inline u64 max_send_read_size(const struct send_ctx *sctx) +{ + return sctx->send_max_size - SZ_16K; +} + +static int put_data_header(struct send_ctx *sctx, u32 len) +{ + if (WARN_ON_ONCE(sctx->put_data)) + return -EINVAL; + sctx->put_data = true; + if (sctx->proto >= 2) { + /* + * Since v2, the data attribute header doesn't include a length, + * it is implicitly to the end of the command. + */ + if (sctx->send_max_size - sctx->send_size < sizeof(__le16) + len) + return -EOVERFLOW; + put_unaligned_le16(BTRFS_SEND_A_DATA, sctx->send_buf + sctx->send_size); + sctx->send_size += sizeof(__le16); + } else { + struct btrfs_tlv_header *hdr; + + if (sctx->send_max_size - sctx->send_size < sizeof(*hdr) + len) + return -EOVERFLOW; + hdr = (struct btrfs_tlv_header *)(sctx->send_buf + sctx->send_size); + put_unaligned_le16(BTRFS_SEND_A_DATA, &hdr->tlv_type); + put_unaligned_le16(len, &hdr->tlv_len); + sctx->send_size += sizeof(*hdr); + } + return 0; +} + +static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len) +{ + struct btrfs_root *root = sctx->send_root; + struct btrfs_fs_info *fs_info = root->fs_info; + struct page *page; + pgoff_t index = offset >> PAGE_SHIFT; + pgoff_t last_index; + unsigned pg_offset = offset_in_page(offset); + int ret; + + ret = put_data_header(sctx, len); + if (ret) + return ret; + + last_index = (offset + len - 1) >> PAGE_SHIFT; + + while (index <= last_index) { + unsigned cur_len = min_t(unsigned, len, + PAGE_SIZE - pg_offset); + + page = find_lock_page(sctx->cur_inode->i_mapping, index); + if (!page) { + page_cache_sync_readahead(sctx->cur_inode->i_mapping, + &sctx->ra, NULL, index, + last_index + 1 - index); + + page = find_or_create_page(sctx->cur_inode->i_mapping, + index, GFP_KERNEL); + if (!page) { + ret = -ENOMEM; + break; + } + } + + if (PageReadahead(page)) + page_cache_async_readahead(sctx->cur_inode->i_mapping, + &sctx->ra, NULL, page_folio(page), + index, last_index + 1 - index); + + if (!PageUptodate(page)) { + btrfs_read_folio(NULL, page_folio(page)); + lock_page(page); + if (!PageUptodate(page)) { + unlock_page(page); + btrfs_err(fs_info, + "send: IO error at offset %llu for inode %llu root %llu", + page_offset(page), sctx->cur_ino, + sctx->send_root->root_key.objectid); + put_page(page); + ret = -EIO; + break; + } + } + + memcpy_from_page(sctx->send_buf + sctx->send_size, page, + pg_offset, cur_len); + unlock_page(page); + put_page(page); + index++; + pg_offset = 0; + len -= cur_len; + sctx->send_size += cur_len; + } + + return ret; +} + +/* + * Read some bytes from the current inode/file and send a write command to + * user space. + */ +static int send_write(struct send_ctx *sctx, u64 offset, u32 len) +{ + struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; + int ret = 0; + struct fs_path *p; + + p = fs_path_alloc(); + if (!p) + return -ENOMEM; + + btrfs_debug(fs_info, "send_write offset=%llu, len=%d", offset, len); + + ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE); + if (ret < 0) + goto out; + + ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); + if (ret < 0) + goto out; + + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); + TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); + ret = put_file_data(sctx, offset, len); + if (ret < 0) + goto out; + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + fs_path_free(p); + return ret; +} + +/* + * Send a clone command to user space. + */ +static int send_clone(struct send_ctx *sctx, + u64 offset, u32 len, + struct clone_root *clone_root) +{ + int ret = 0; + struct fs_path *p; + u64 gen; + + btrfs_debug(sctx->send_root->fs_info, + "send_clone offset=%llu, len=%d, clone_root=%llu, clone_inode=%llu, clone_offset=%llu", + offset, len, clone_root->root->root_key.objectid, + clone_root->ino, clone_root->offset); + + p = fs_path_alloc(); + if (!p) + return -ENOMEM; + + ret = begin_cmd(sctx, BTRFS_SEND_C_CLONE); + if (ret < 0) + goto out; + + ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); + if (ret < 0) + goto out; + + TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); + TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_LEN, len); + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); + + if (clone_root->root == sctx->send_root) { + ret = get_inode_gen(sctx->send_root, clone_root->ino, &gen); + if (ret < 0) + goto out; + ret = get_cur_path(sctx, clone_root->ino, gen, p); + } else { + ret = get_inode_path(clone_root->root, clone_root->ino, p); + } + if (ret < 0) + goto out; + + /* + * If the parent we're using has a received_uuid set then use that as + * our clone source as that is what we will look for when doing a + * receive. + * + * This covers the case that we create a snapshot off of a received + * subvolume and then use that as the parent and try to receive on a + * different host. + */ + if (!btrfs_is_empty_uuid(clone_root->root->root_item.received_uuid)) + TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, + clone_root->root->root_item.received_uuid); + else + TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, + clone_root->root->root_item.uuid); + TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID, + btrfs_root_ctransid(&clone_root->root->root_item)); + TLV_PUT_PATH(sctx, BTRFS_SEND_A_CLONE_PATH, p); + TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_OFFSET, + clone_root->offset); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + fs_path_free(p); + return ret; +} + +/* + * Send an update extent command to user space. + */ +static int send_update_extent(struct send_ctx *sctx, + u64 offset, u32 len) +{ + int ret = 0; + struct fs_path *p; + + p = fs_path_alloc(); + if (!p) + return -ENOMEM; + + ret = begin_cmd(sctx, BTRFS_SEND_C_UPDATE_EXTENT); + if (ret < 0) + goto out; + + ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); + if (ret < 0) + goto out; + + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); + TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); + TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, len); + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + fs_path_free(p); + return ret; +} + +static int send_hole(struct send_ctx *sctx, u64 end) +{ + struct fs_path *p = NULL; + u64 read_size = max_send_read_size(sctx); + u64 offset = sctx->cur_inode_last_extent; + int ret = 0; + + /* + * A hole that starts at EOF or beyond it. Since we do not yet support + * fallocate (for extent preallocation and hole punching), sending a + * write of zeroes starting at EOF or beyond would later require issuing + * a truncate operation which would undo the write and achieve nothing. + */ + if (offset >= sctx->cur_inode_size) + return 0; + + /* + * Don't go beyond the inode's i_size due to prealloc extents that start + * after the i_size. + */ + end = min_t(u64, end, sctx->cur_inode_size); + + if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA) + return send_update_extent(sctx, offset, end - offset); + + p = fs_path_alloc(); + if (!p) + return -ENOMEM; + ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); + if (ret < 0) + goto tlv_put_failure; + while (offset < end) { + u64 len = min(end - offset, read_size); + + ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE); + if (ret < 0) + break; + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); + TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); + ret = put_data_header(sctx, len); + if (ret < 0) + break; + memset(sctx->send_buf + sctx->send_size, 0, len); + sctx->send_size += len; + ret = send_cmd(sctx); + if (ret < 0) + break; + offset += len; + } + sctx->cur_inode_next_write_offset = offset; +tlv_put_failure: + fs_path_free(p); + return ret; +} + +static int send_encoded_inline_extent(struct send_ctx *sctx, + struct btrfs_path *path, u64 offset, + u64 len) +{ + struct btrfs_root *root = sctx->send_root; + struct btrfs_fs_info *fs_info = root->fs_info; + struct inode *inode; + struct fs_path *fspath; + struct extent_buffer *leaf = path->nodes[0]; + struct btrfs_key key; + struct btrfs_file_extent_item *ei; + u64 ram_bytes; + size_t inline_size; + int ret; + + inode = btrfs_iget(fs_info->sb, sctx->cur_ino, root); + if (IS_ERR(inode)) + return PTR_ERR(inode); + + fspath = fs_path_alloc(); + if (!fspath) { + ret = -ENOMEM; + goto out; + } + + ret = begin_cmd(sctx, BTRFS_SEND_C_ENCODED_WRITE); + if (ret < 0) + goto out; + + ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, fspath); + if (ret < 0) + goto out; + + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item); + ram_bytes = btrfs_file_extent_ram_bytes(leaf, ei); + inline_size = btrfs_file_extent_inline_item_len(leaf, path->slots[0]); + + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, fspath); + TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); + TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_FILE_LEN, + min(key.offset + ram_bytes - offset, len)); + TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_LEN, ram_bytes); + TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_OFFSET, offset - key.offset); + ret = btrfs_encoded_io_compression_from_extent(fs_info, + btrfs_file_extent_compression(leaf, ei)); + if (ret < 0) + goto out; + TLV_PUT_U32(sctx, BTRFS_SEND_A_COMPRESSION, ret); + + ret = put_data_header(sctx, inline_size); + if (ret < 0) + goto out; + read_extent_buffer(leaf, sctx->send_buf + sctx->send_size, + btrfs_file_extent_inline_start(ei), inline_size); + sctx->send_size += inline_size; + + ret = send_cmd(sctx); + +tlv_put_failure: +out: + fs_path_free(fspath); + iput(inode); + return ret; +} + +static int send_encoded_extent(struct send_ctx *sctx, struct btrfs_path *path, + u64 offset, u64 len) +{ + struct btrfs_root *root = sctx->send_root; + struct btrfs_fs_info *fs_info = root->fs_info; + struct inode *inode; + struct fs_path *fspath; + struct extent_buffer *leaf = path->nodes[0]; + struct btrfs_key key; + struct btrfs_file_extent_item *ei; + u64 disk_bytenr, disk_num_bytes; + u32 data_offset; + struct btrfs_cmd_header *hdr; + u32 crc; + int ret; + + inode = btrfs_iget(fs_info->sb, sctx->cur_ino, root); + if (IS_ERR(inode)) + return PTR_ERR(inode); + + fspath = fs_path_alloc(); + if (!fspath) { + ret = -ENOMEM; + goto out; + } + + ret = begin_cmd(sctx, BTRFS_SEND_C_ENCODED_WRITE); + if (ret < 0) + goto out; + + ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, fspath); + if (ret < 0) + goto out; + + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item); + disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, ei); + disk_num_bytes = btrfs_file_extent_disk_num_bytes(leaf, ei); + + TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, fspath); + TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); + TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_FILE_LEN, + min(key.offset + btrfs_file_extent_num_bytes(leaf, ei) - offset, + len)); + TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_LEN, + btrfs_file_extent_ram_bytes(leaf, ei)); + TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_OFFSET, + offset - key.offset + btrfs_file_extent_offset(leaf, ei)); + ret = btrfs_encoded_io_compression_from_extent(fs_info, + btrfs_file_extent_compression(leaf, ei)); + if (ret < 0) + goto out; + TLV_PUT_U32(sctx, BTRFS_SEND_A_COMPRESSION, ret); + TLV_PUT_U32(sctx, BTRFS_SEND_A_ENCRYPTION, 0); + + ret = put_data_header(sctx, disk_num_bytes); + if (ret < 0) + goto out; + + /* + * We want to do I/O directly into the send buffer, so get the next page + * boundary in the send buffer. This means that there may be a gap + * between the beginning of the command and the file data. + */ + data_offset = ALIGN(sctx->send_size, PAGE_SIZE); + if (data_offset > sctx->send_max_size || + sctx->send_max_size - data_offset < disk_num_bytes) { + ret = -EOVERFLOW; + goto out; + } + + /* + * Note that send_buf is a mapping of send_buf_pages, so this is really + * reading into send_buf. + */ + ret = btrfs_encoded_read_regular_fill_pages(BTRFS_I(inode), offset, + disk_bytenr, disk_num_bytes, + sctx->send_buf_pages + + (data_offset >> PAGE_SHIFT)); + if (ret) + goto out; + + hdr = (struct btrfs_cmd_header *)sctx->send_buf; + hdr->len = cpu_to_le32(sctx->send_size + disk_num_bytes - sizeof(*hdr)); + hdr->crc = 0; + crc = btrfs_crc32c(0, sctx->send_buf, sctx->send_size); + crc = btrfs_crc32c(crc, sctx->send_buf + data_offset, disk_num_bytes); + hdr->crc = cpu_to_le32(crc); + + ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size, + &sctx->send_off); + if (!ret) { + ret = write_buf(sctx->send_filp, sctx->send_buf + data_offset, + disk_num_bytes, &sctx->send_off); + } + sctx->send_size = 0; + sctx->put_data = false; + +tlv_put_failure: +out: + fs_path_free(fspath); + iput(inode); + return ret; +} + +static int send_extent_data(struct send_ctx *sctx, struct btrfs_path *path, + const u64 offset, const u64 len) +{ + const u64 end = offset + len; + struct extent_buffer *leaf = path->nodes[0]; + struct btrfs_file_extent_item *ei; + u64 read_size = max_send_read_size(sctx); + u64 sent = 0; + + if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA) + return send_update_extent(sctx, offset, len); + + ei = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + if ((sctx->flags & BTRFS_SEND_FLAG_COMPRESSED) && + btrfs_file_extent_compression(leaf, ei) != BTRFS_COMPRESS_NONE) { + bool is_inline = (btrfs_file_extent_type(leaf, ei) == + BTRFS_FILE_EXTENT_INLINE); + + /* + * Send the compressed extent unless the compressed data is + * larger than the decompressed data. This can happen if we're + * not sending the entire extent, either because it has been + * partially overwritten/truncated or because this is a part of + * the extent that we couldn't clone in clone_range(). + */ + if (is_inline && + btrfs_file_extent_inline_item_len(leaf, + path->slots[0]) <= len) { + return send_encoded_inline_extent(sctx, path, offset, + len); + } else if (!is_inline && + btrfs_file_extent_disk_num_bytes(leaf, ei) <= len) { + return send_encoded_extent(sctx, path, offset, len); + } + } + + if (sctx->cur_inode == NULL) { + struct btrfs_root *root = sctx->send_root; + + sctx->cur_inode = btrfs_iget(root->fs_info->sb, sctx->cur_ino, root); + if (IS_ERR(sctx->cur_inode)) { + int err = PTR_ERR(sctx->cur_inode); + + sctx->cur_inode = NULL; + return err; + } + memset(&sctx->ra, 0, sizeof(struct file_ra_state)); + file_ra_state_init(&sctx->ra, sctx->cur_inode->i_mapping); + + /* + * It's very likely there are no pages from this inode in the page + * cache, so after reading extents and sending their data, we clean + * the page cache to avoid trashing the page cache (adding pressure + * to the page cache and forcing eviction of other data more useful + * for applications). + * + * We decide if we should clean the page cache simply by checking + * if the inode's mapping nrpages is 0 when we first open it, and + * not by using something like filemap_range_has_page() before + * reading an extent because when we ask the readahead code to + * read a given file range, it may (and almost always does) read + * pages from beyond that range (see the documentation for + * page_cache_sync_readahead()), so it would not be reliable, + * because after reading the first extent future calls to + * filemap_range_has_page() would return true because the readahead + * on the previous extent resulted in reading pages of the current + * extent as well. + */ + sctx->clean_page_cache = (sctx->cur_inode->i_mapping->nrpages == 0); + sctx->page_cache_clear_start = round_down(offset, PAGE_SIZE); + } + + while (sent < len) { + u64 size = min(len - sent, read_size); + int ret; + + ret = send_write(sctx, offset + sent, size); + if (ret < 0) + return ret; + sent += size; + } + + if (sctx->clean_page_cache && IS_ALIGNED(end, PAGE_SIZE)) { + /* + * Always operate only on ranges that are a multiple of the page + * size. This is not only to prevent zeroing parts of a page in + * the case of subpage sector size, but also to guarantee we evict + * pages, as passing a range that is smaller than page size does + * not evict the respective page (only zeroes part of its content). + * + * Always start from the end offset of the last range cleared. + * This is because the readahead code may (and very often does) + * reads pages beyond the range we request for readahead. So if + * we have an extent layout like this: + * + * [ extent A ] [ extent B ] [ extent C ] + * + * When we ask page_cache_sync_readahead() to read extent A, it + * may also trigger reads for pages of extent B. If we are doing + * an incremental send and extent B has not changed between the + * parent and send snapshots, some or all of its pages may end + * up being read and placed in the page cache. So when truncating + * the page cache we always start from the end offset of the + * previously processed extent up to the end of the current + * extent. + */ + truncate_inode_pages_range(&sctx->cur_inode->i_data, + sctx->page_cache_clear_start, + end - 1); + sctx->page_cache_clear_start = end; + } + + return 0; +} + +/* + * Search for a capability xattr related to sctx->cur_ino. If the capability is + * found, call send_set_xattr function to emit it. + * + * Return 0 if there isn't a capability, or when the capability was emitted + * successfully, or < 0 if an error occurred. + */ +static int send_capabilities(struct send_ctx *sctx) +{ + struct fs_path *fspath = NULL; + struct btrfs_path *path; + struct btrfs_dir_item *di; + struct extent_buffer *leaf; + unsigned long data_ptr; + char *buf = NULL; + int buf_len; + int ret = 0; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + di = btrfs_lookup_xattr(NULL, sctx->send_root, path, sctx->cur_ino, + XATTR_NAME_CAPS, strlen(XATTR_NAME_CAPS), 0); + if (!di) { + /* There is no xattr for this inode */ + goto out; + } else if (IS_ERR(di)) { + ret = PTR_ERR(di); + goto out; + } + + leaf = path->nodes[0]; + buf_len = btrfs_dir_data_len(leaf, di); + + fspath = fs_path_alloc(); + buf = kmalloc(buf_len, GFP_KERNEL); + if (!fspath || !buf) { + ret = -ENOMEM; + goto out; + } + + ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, fspath); + if (ret < 0) + goto out; + + data_ptr = (unsigned long)(di + 1) + btrfs_dir_name_len(leaf, di); + read_extent_buffer(leaf, buf, data_ptr, buf_len); + + ret = send_set_xattr(sctx, fspath, XATTR_NAME_CAPS, + strlen(XATTR_NAME_CAPS), buf, buf_len); +out: + kfree(buf); + fs_path_free(fspath); + btrfs_free_path(path); + return ret; +} + +static int clone_range(struct send_ctx *sctx, struct btrfs_path *dst_path, + struct clone_root *clone_root, const u64 disk_byte, + u64 data_offset, u64 offset, u64 len) +{ + struct btrfs_path *path; + struct btrfs_key key; + int ret; + struct btrfs_inode_info info; + u64 clone_src_i_size = 0; + + /* + * Prevent cloning from a zero offset with a length matching the sector + * size because in some scenarios this will make the receiver fail. + * + * For example, if in the source filesystem the extent at offset 0 + * has a length of sectorsize and it was written using direct IO, then + * it can never be an inline extent (even if compression is enabled). + * Then this extent can be cloned in the original filesystem to a non + * zero file offset, but it may not be possible to clone in the + * destination filesystem because it can be inlined due to compression + * on the destination filesystem (as the receiver's write operations are + * always done using buffered IO). The same happens when the original + * filesystem does not have compression enabled but the destination + * filesystem has. + */ + if (clone_root->offset == 0 && + len == sctx->send_root->fs_info->sectorsize) + return send_extent_data(sctx, dst_path, offset, len); + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + /* + * There are inodes that have extents that lie behind its i_size. Don't + * accept clones from these extents. + */ + ret = get_inode_info(clone_root->root, clone_root->ino, &info); + btrfs_release_path(path); + if (ret < 0) + goto out; + clone_src_i_size = info.size; + + /* + * We can't send a clone operation for the entire range if we find + * extent items in the respective range in the source file that + * refer to different extents or if we find holes. + * So check for that and do a mix of clone and regular write/copy + * operations if needed. + * + * Example: + * + * mkfs.btrfs -f /dev/sda + * mount /dev/sda /mnt + * xfs_io -f -c "pwrite -S 0xaa 0K 100K" /mnt/foo + * cp --reflink=always /mnt/foo /mnt/bar + * xfs_io -c "pwrite -S 0xbb 50K 50K" /mnt/foo + * btrfs subvolume snapshot -r /mnt /mnt/snap + * + * If when we send the snapshot and we are processing file bar (which + * has a higher inode number than foo) we blindly send a clone operation + * for the [0, 100K[ range from foo to bar, the receiver ends up getting + * a file bar that matches the content of file foo - iow, doesn't match + * the content from bar in the original filesystem. + */ + key.objectid = clone_root->ino; + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = clone_root->offset; + ret = btrfs_search_slot(NULL, clone_root->root, &key, path, 0, 0); + if (ret < 0) + goto out; + if (ret > 0 && path->slots[0] > 0) { + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1); + if (key.objectid == clone_root->ino && + key.type == BTRFS_EXTENT_DATA_KEY) + path->slots[0]--; + } + + while (true) { + struct extent_buffer *leaf = path->nodes[0]; + int slot = path->slots[0]; + struct btrfs_file_extent_item *ei; + u8 type; + u64 ext_len; + u64 clone_len; + u64 clone_data_offset; + bool crossed_src_i_size = false; + + if (slot >= btrfs_header_nritems(leaf)) { + ret = btrfs_next_leaf(clone_root->root, path); + if (ret < 0) + goto out; + else if (ret > 0) + break; + continue; + } + + btrfs_item_key_to_cpu(leaf, &key, slot); + + /* + * We might have an implicit trailing hole (NO_HOLES feature + * enabled). We deal with it after leaving this loop. + */ + if (key.objectid != clone_root->ino || + key.type != BTRFS_EXTENT_DATA_KEY) + break; + + ei = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); + type = btrfs_file_extent_type(leaf, ei); + if (type == BTRFS_FILE_EXTENT_INLINE) { + ext_len = btrfs_file_extent_ram_bytes(leaf, ei); + ext_len = PAGE_ALIGN(ext_len); + } else { + ext_len = btrfs_file_extent_num_bytes(leaf, ei); + } + + if (key.offset + ext_len <= clone_root->offset) + goto next; + + if (key.offset > clone_root->offset) { + /* Implicit hole, NO_HOLES feature enabled. */ + u64 hole_len = key.offset - clone_root->offset; + + if (hole_len > len) + hole_len = len; + ret = send_extent_data(sctx, dst_path, offset, + hole_len); + if (ret < 0) + goto out; + + len -= hole_len; + if (len == 0) + break; + offset += hole_len; + clone_root->offset += hole_len; + data_offset += hole_len; + } + + if (key.offset >= clone_root->offset + len) + break; + + if (key.offset >= clone_src_i_size) + break; + + if (key.offset + ext_len > clone_src_i_size) { + ext_len = clone_src_i_size - key.offset; + crossed_src_i_size = true; + } + + clone_data_offset = btrfs_file_extent_offset(leaf, ei); + if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte) { + clone_root->offset = key.offset; + if (clone_data_offset < data_offset && + clone_data_offset + ext_len > data_offset) { + u64 extent_offset; + + extent_offset = data_offset - clone_data_offset; + ext_len -= extent_offset; + clone_data_offset += extent_offset; + clone_root->offset += extent_offset; + } + } + + clone_len = min_t(u64, ext_len, len); + + if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte && + clone_data_offset == data_offset) { + const u64 src_end = clone_root->offset + clone_len; + const u64 sectorsize = SZ_64K; + + /* + * We can't clone the last block, when its size is not + * sector size aligned, into the middle of a file. If we + * do so, the receiver will get a failure (-EINVAL) when + * trying to clone or will silently corrupt the data in + * the destination file if it's on a kernel without the + * fix introduced by commit ac765f83f1397646 + * ("Btrfs: fix data corruption due to cloning of eof + * block). + * + * So issue a clone of the aligned down range plus a + * regular write for the eof block, if we hit that case. + * + * Also, we use the maximum possible sector size, 64K, + * because we don't know what's the sector size of the + * filesystem that receives the stream, so we have to + * assume the largest possible sector size. + */ + if (src_end == clone_src_i_size && + !IS_ALIGNED(src_end, sectorsize) && + offset + clone_len < sctx->cur_inode_size) { + u64 slen; + + slen = ALIGN_DOWN(src_end - clone_root->offset, + sectorsize); + if (slen > 0) { + ret = send_clone(sctx, offset, slen, + clone_root); + if (ret < 0) + goto out; + } + ret = send_extent_data(sctx, dst_path, + offset + slen, + clone_len - slen); + } else { + ret = send_clone(sctx, offset, clone_len, + clone_root); + } + } else if (crossed_src_i_size && clone_len < len) { + /* + * If we are at i_size of the clone source inode and we + * can not clone from it, terminate the loop. This is + * to avoid sending two write operations, one with a + * length matching clone_len and the final one after + * this loop with a length of len - clone_len. + * + * When using encoded writes (BTRFS_SEND_FLAG_COMPRESSED + * was passed to the send ioctl), this helps avoid + * sending an encoded write for an offset that is not + * sector size aligned, in case the i_size of the source + * inode is not sector size aligned. That will make the + * receiver fallback to decompression of the data and + * writing it using regular buffered IO, therefore while + * not incorrect, it's not optimal due decompression and + * possible re-compression at the receiver. + */ + break; + } else { + ret = send_extent_data(sctx, dst_path, offset, + clone_len); + } + + if (ret < 0) + goto out; + + len -= clone_len; + if (len == 0) + break; + offset += clone_len; + clone_root->offset += clone_len; + + /* + * If we are cloning from the file we are currently processing, + * and using the send root as the clone root, we must stop once + * the current clone offset reaches the current eof of the file + * at the receiver, otherwise we would issue an invalid clone + * operation (source range going beyond eof) and cause the + * receiver to fail. So if we reach the current eof, bail out + * and fallback to a regular write. + */ + if (clone_root->root == sctx->send_root && + clone_root->ino == sctx->cur_ino && + clone_root->offset >= sctx->cur_inode_next_write_offset) + break; + + data_offset += clone_len; +next: + path->slots[0]++; + } + + if (len > 0) + ret = send_extent_data(sctx, dst_path, offset, len); + else + ret = 0; +out: + btrfs_free_path(path); + return ret; +} + +static int send_write_or_clone(struct send_ctx *sctx, + struct btrfs_path *path, + struct btrfs_key *key, + struct clone_root *clone_root) +{ + int ret = 0; + u64 offset = key->offset; + u64 end; + u64 bs = sctx->send_root->fs_info->sb->s_blocksize; + + end = min_t(u64, btrfs_file_extent_end(path), sctx->cur_inode_size); + if (offset >= end) + return 0; + + if (clone_root && IS_ALIGNED(end, bs)) { + struct btrfs_file_extent_item *ei; + u64 disk_byte; + u64 data_offset; + + ei = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_file_extent_item); + disk_byte = btrfs_file_extent_disk_bytenr(path->nodes[0], ei); + data_offset = btrfs_file_extent_offset(path->nodes[0], ei); + ret = clone_range(sctx, path, clone_root, disk_byte, + data_offset, offset, end - offset); + } else { + ret = send_extent_data(sctx, path, offset, end - offset); + } + sctx->cur_inode_next_write_offset = end; + return ret; +} + +static int is_extent_unchanged(struct send_ctx *sctx, + struct btrfs_path *left_path, + struct btrfs_key *ekey) +{ + int ret = 0; + struct btrfs_key key; + struct btrfs_path *path = NULL; + struct extent_buffer *eb; + int slot; + struct btrfs_key found_key; + struct btrfs_file_extent_item *ei; + u64 left_disknr; + u64 right_disknr; + u64 left_offset; + u64 right_offset; + u64 left_offset_fixed; + u64 left_len; + u64 right_len; + u64 left_gen; + u64 right_gen; + u8 left_type; + u8 right_type; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + eb = left_path->nodes[0]; + slot = left_path->slots[0]; + ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); + left_type = btrfs_file_extent_type(eb, ei); + + if (left_type != BTRFS_FILE_EXTENT_REG) { + ret = 0; + goto out; + } + left_disknr = btrfs_file_extent_disk_bytenr(eb, ei); + left_len = btrfs_file_extent_num_bytes(eb, ei); + left_offset = btrfs_file_extent_offset(eb, ei); + left_gen = btrfs_file_extent_generation(eb, ei); + + /* + * Following comments will refer to these graphics. L is the left + * extents which we are checking at the moment. 1-8 are the right + * extents that we iterate. + * + * |-----L-----| + * |-1-|-2a-|-3-|-4-|-5-|-6-| + * + * |-----L-----| + * |--1--|-2b-|...(same as above) + * + * Alternative situation. Happens on files where extents got split. + * |-----L-----| + * |-----------7-----------|-6-| + * + * Alternative situation. Happens on files which got larger. + * |-----L-----| + * |-8-| + * Nothing follows after 8. + */ + + key.objectid = ekey->objectid; + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = ekey->offset; + ret = btrfs_search_slot_for_read(sctx->parent_root, &key, path, 0, 0); + if (ret < 0) + goto out; + if (ret) { + ret = 0; + goto out; + } + + /* + * Handle special case where the right side has no extents at all. + */ + eb = path->nodes[0]; + slot = path->slots[0]; + btrfs_item_key_to_cpu(eb, &found_key, slot); + if (found_key.objectid != key.objectid || + found_key.type != key.type) { + /* If we're a hole then just pretend nothing changed */ + ret = (left_disknr) ? 0 : 1; + goto out; + } + + /* + * We're now on 2a, 2b or 7. + */ + key = found_key; + while (key.offset < ekey->offset + left_len) { + ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); + right_type = btrfs_file_extent_type(eb, ei); + if (right_type != BTRFS_FILE_EXTENT_REG && + right_type != BTRFS_FILE_EXTENT_INLINE) { + ret = 0; + goto out; + } + + if (right_type == BTRFS_FILE_EXTENT_INLINE) { + right_len = btrfs_file_extent_ram_bytes(eb, ei); + right_len = PAGE_ALIGN(right_len); + } else { + right_len = btrfs_file_extent_num_bytes(eb, ei); + } + + /* + * Are we at extent 8? If yes, we know the extent is changed. + * This may only happen on the first iteration. + */ + if (found_key.offset + right_len <= ekey->offset) { + /* If we're a hole just pretend nothing changed */ + ret = (left_disknr) ? 0 : 1; + goto out; + } + + /* + * We just wanted to see if when we have an inline extent, what + * follows it is a regular extent (wanted to check the above + * condition for inline extents too). This should normally not + * happen but it's possible for example when we have an inline + * compressed extent representing data with a size matching + * the page size (currently the same as sector size). + */ + if (right_type == BTRFS_FILE_EXTENT_INLINE) { + ret = 0; + goto out; + } + + right_disknr = btrfs_file_extent_disk_bytenr(eb, ei); + right_offset = btrfs_file_extent_offset(eb, ei); + right_gen = btrfs_file_extent_generation(eb, ei); + + left_offset_fixed = left_offset; + if (key.offset < ekey->offset) { + /* Fix the right offset for 2a and 7. */ + right_offset += ekey->offset - key.offset; + } else { + /* Fix the left offset for all behind 2a and 2b */ + left_offset_fixed += key.offset - ekey->offset; + } + + /* + * Check if we have the same extent. + */ + if (left_disknr != right_disknr || + left_offset_fixed != right_offset || + left_gen != right_gen) { + ret = 0; + goto out; + } + + /* + * Go to the next extent. + */ + ret = btrfs_next_item(sctx->parent_root, path); + if (ret < 0) + goto out; + if (!ret) { + eb = path->nodes[0]; + slot = path->slots[0]; + btrfs_item_key_to_cpu(eb, &found_key, slot); + } + if (ret || found_key.objectid != key.objectid || + found_key.type != key.type) { + key.offset += right_len; + break; + } + if (found_key.offset != key.offset + right_len) { + ret = 0; + goto out; + } + key = found_key; + } + + /* + * We're now behind the left extent (treat as unchanged) or at the end + * of the right side (treat as changed). + */ + if (key.offset >= ekey->offset + left_len) + ret = 1; + else + ret = 0; + + +out: + btrfs_free_path(path); + return ret; +} + +static int get_last_extent(struct send_ctx *sctx, u64 offset) +{ + struct btrfs_path *path; + struct btrfs_root *root = sctx->send_root; + struct btrfs_key key; + int ret; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + sctx->cur_inode_last_extent = 0; + + key.objectid = sctx->cur_ino; + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = offset; + ret = btrfs_search_slot_for_read(root, &key, path, 0, 1); + if (ret < 0) + goto out; + ret = 0; + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); + if (key.objectid != sctx->cur_ino || key.type != BTRFS_EXTENT_DATA_KEY) + goto out; + + sctx->cur_inode_last_extent = btrfs_file_extent_end(path); +out: + btrfs_free_path(path); + return ret; +} + +static int range_is_hole_in_parent(struct send_ctx *sctx, + const u64 start, + const u64 end) +{ + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_root *root = sctx->parent_root; + u64 search_start = start; + int ret; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + key.objectid = sctx->cur_ino; + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = search_start; + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) + goto out; + if (ret > 0 && path->slots[0] > 0) + path->slots[0]--; + + while (search_start < end) { + struct extent_buffer *leaf = path->nodes[0]; + int slot = path->slots[0]; + struct btrfs_file_extent_item *fi; + u64 extent_end; + + if (slot >= btrfs_header_nritems(leaf)) { + ret = btrfs_next_leaf(root, path); + if (ret < 0) + goto out; + else if (ret > 0) + break; + continue; + } + + btrfs_item_key_to_cpu(leaf, &key, slot); + if (key.objectid < sctx->cur_ino || + key.type < BTRFS_EXTENT_DATA_KEY) + goto next; + if (key.objectid > sctx->cur_ino || + key.type > BTRFS_EXTENT_DATA_KEY || + key.offset >= end) + break; + + fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); + extent_end = btrfs_file_extent_end(path); + if (extent_end <= start) + goto next; + if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0) { + search_start = extent_end; + goto next; + } + ret = 0; + goto out; +next: + path->slots[0]++; + } + ret = 1; +out: + btrfs_free_path(path); + return ret; +} + +static int maybe_send_hole(struct send_ctx *sctx, struct btrfs_path *path, + struct btrfs_key *key) +{ + int ret = 0; + + if (sctx->cur_ino != key->objectid || !need_send_hole(sctx)) + return 0; + + if (sctx->cur_inode_last_extent == (u64)-1) { + ret = get_last_extent(sctx, key->offset - 1); + if (ret) + return ret; + } + + if (path->slots[0] == 0 && + sctx->cur_inode_last_extent < key->offset) { + /* + * We might have skipped entire leafs that contained only + * file extent items for our current inode. These leafs have + * a generation number smaller (older) than the one in the + * current leaf and the leaf our last extent came from, and + * are located between these 2 leafs. + */ + ret = get_last_extent(sctx, key->offset - 1); + if (ret) + return ret; + } + + if (sctx->cur_inode_last_extent < key->offset) { + ret = range_is_hole_in_parent(sctx, + sctx->cur_inode_last_extent, + key->offset); + if (ret < 0) + return ret; + else if (ret == 0) + ret = send_hole(sctx, key->offset); + else + ret = 0; + } + sctx->cur_inode_last_extent = btrfs_file_extent_end(path); + return ret; +} + +static int process_extent(struct send_ctx *sctx, + struct btrfs_path *path, + struct btrfs_key *key) +{ + struct clone_root *found_clone = NULL; + int ret = 0; + + if (S_ISLNK(sctx->cur_inode_mode)) + return 0; + + if (sctx->parent_root && !sctx->cur_inode_new) { + ret = is_extent_unchanged(sctx, path, key); + if (ret < 0) + goto out; + if (ret) { + ret = 0; + goto out_hole; + } + } else { + struct btrfs_file_extent_item *ei; + u8 type; + + ei = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_file_extent_item); + type = btrfs_file_extent_type(path->nodes[0], ei); + if (type == BTRFS_FILE_EXTENT_PREALLOC || + type == BTRFS_FILE_EXTENT_REG) { + /* + * The send spec does not have a prealloc command yet, + * so just leave a hole for prealloc'ed extents until + * we have enough commands queued up to justify rev'ing + * the send spec. + */ + if (type == BTRFS_FILE_EXTENT_PREALLOC) { + ret = 0; + goto out; + } + + /* Have a hole, just skip it. */ + if (btrfs_file_extent_disk_bytenr(path->nodes[0], ei) == 0) { + ret = 0; + goto out; + } + } + } + + ret = find_extent_clone(sctx, path, key->objectid, key->offset, + sctx->cur_inode_size, &found_clone); + if (ret != -ENOENT && ret < 0) + goto out; + + ret = send_write_or_clone(sctx, path, key, found_clone); + if (ret) + goto out; +out_hole: + ret = maybe_send_hole(sctx, path, key); +out: + return ret; +} + +static int process_all_extents(struct send_ctx *sctx) +{ + int ret = 0; + int iter_ret = 0; + struct btrfs_root *root; + struct btrfs_path *path; + struct btrfs_key key; + struct btrfs_key found_key; + + root = sctx->send_root; + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + key.objectid = sctx->cmp_key->objectid; + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = 0; + btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) { + if (found_key.objectid != key.objectid || + found_key.type != key.type) { + ret = 0; + break; + } + + ret = process_extent(sctx, path, &found_key); + if (ret < 0) + break; + } + /* Catch error found during iteration */ + if (iter_ret < 0) + ret = iter_ret; + + btrfs_free_path(path); + return ret; +} + +static int process_recorded_refs_if_needed(struct send_ctx *sctx, int at_end, + int *pending_move, + int *refs_processed) +{ + int ret = 0; + + if (sctx->cur_ino == 0) + goto out; + if (!at_end && sctx->cur_ino == sctx->cmp_key->objectid && + sctx->cmp_key->type <= BTRFS_INODE_EXTREF_KEY) + goto out; + if (list_empty(&sctx->new_refs) && list_empty(&sctx->deleted_refs)) + goto out; + + ret = process_recorded_refs(sctx, pending_move); + if (ret < 0) + goto out; + + *refs_processed = 1; +out: + return ret; +} + +static int finish_inode_if_needed(struct send_ctx *sctx, int at_end) +{ + int ret = 0; + struct btrfs_inode_info info; + u64 left_mode; + u64 left_uid; + u64 left_gid; + u64 left_fileattr; + u64 right_mode; + u64 right_uid; + u64 right_gid; + u64 right_fileattr; + int need_chmod = 0; + int need_chown = 0; + bool need_fileattr = false; + int need_truncate = 1; + int pending_move = 0; + int refs_processed = 0; + + if (sctx->ignore_cur_inode) + return 0; + + ret = process_recorded_refs_if_needed(sctx, at_end, &pending_move, + &refs_processed); + if (ret < 0) + goto out; + + /* + * We have processed the refs and thus need to advance send_progress. + * Now, calls to get_cur_xxx will take the updated refs of the current + * inode into account. + * + * On the other hand, if our current inode is a directory and couldn't + * be moved/renamed because its parent was renamed/moved too and it has + * a higher inode number, we can only move/rename our current inode + * after we moved/renamed its parent. Therefore in this case operate on + * the old path (pre move/rename) of our current inode, and the + * move/rename will be performed later. + */ + if (refs_processed && !pending_move) + sctx->send_progress = sctx->cur_ino + 1; + + if (sctx->cur_ino == 0 || sctx->cur_inode_deleted) + goto out; + if (!at_end && sctx->cmp_key->objectid == sctx->cur_ino) + goto out; + ret = get_inode_info(sctx->send_root, sctx->cur_ino, &info); + if (ret < 0) + goto out; + left_mode = info.mode; + left_uid = info.uid; + left_gid = info.gid; + left_fileattr = info.fileattr; + + if (!sctx->parent_root || sctx->cur_inode_new) { + need_chown = 1; + if (!S_ISLNK(sctx->cur_inode_mode)) + need_chmod = 1; + if (sctx->cur_inode_next_write_offset == sctx->cur_inode_size) + need_truncate = 0; + } else { + u64 old_size; + + ret = get_inode_info(sctx->parent_root, sctx->cur_ino, &info); + if (ret < 0) + goto out; + old_size = info.size; + right_mode = info.mode; + right_uid = info.uid; + right_gid = info.gid; + right_fileattr = info.fileattr; + + if (left_uid != right_uid || left_gid != right_gid) + need_chown = 1; + if (!S_ISLNK(sctx->cur_inode_mode) && left_mode != right_mode) + need_chmod = 1; + if (!S_ISLNK(sctx->cur_inode_mode) && left_fileattr != right_fileattr) + need_fileattr = true; + if ((old_size == sctx->cur_inode_size) || + (sctx->cur_inode_size > old_size && + sctx->cur_inode_next_write_offset == sctx->cur_inode_size)) + need_truncate = 0; + } + + if (S_ISREG(sctx->cur_inode_mode)) { + if (need_send_hole(sctx)) { + if (sctx->cur_inode_last_extent == (u64)-1 || + sctx->cur_inode_last_extent < + sctx->cur_inode_size) { + ret = get_last_extent(sctx, (u64)-1); + if (ret) + goto out; + } + if (sctx->cur_inode_last_extent < + sctx->cur_inode_size) { + ret = send_hole(sctx, sctx->cur_inode_size); + if (ret) + goto out; + } + } + if (need_truncate) { + ret = send_truncate(sctx, sctx->cur_ino, + sctx->cur_inode_gen, + sctx->cur_inode_size); + if (ret < 0) + goto out; + } + } + + if (need_chown) { + ret = send_chown(sctx, sctx->cur_ino, sctx->cur_inode_gen, + left_uid, left_gid); + if (ret < 0) + goto out; + } + if (need_chmod) { + ret = send_chmod(sctx, sctx->cur_ino, sctx->cur_inode_gen, + left_mode); + if (ret < 0) + goto out; + } + if (need_fileattr) { + ret = send_fileattr(sctx, sctx->cur_ino, sctx->cur_inode_gen, + left_fileattr); + if (ret < 0) + goto out; + } + + if (proto_cmd_ok(sctx, BTRFS_SEND_C_ENABLE_VERITY) + && sctx->cur_inode_needs_verity) { + ret = process_verity(sctx); + if (ret < 0) + goto out; + } + + ret = send_capabilities(sctx); + if (ret < 0) + goto out; + + /* + * If other directory inodes depended on our current directory + * inode's move/rename, now do their move/rename operations. + */ + if (!is_waiting_for_move(sctx, sctx->cur_ino)) { + ret = apply_children_dir_moves(sctx); + if (ret) + goto out; + /* + * Need to send that every time, no matter if it actually + * changed between the two trees as we have done changes to + * the inode before. If our inode is a directory and it's + * waiting to be moved/renamed, we will send its utimes when + * it's moved/renamed, therefore we don't need to do it here. + */ + sctx->send_progress = sctx->cur_ino + 1; + ret = send_utimes(sctx, sctx->cur_ino, sctx->cur_inode_gen); + if (ret < 0) + goto out; + } + +out: + return ret; +} + +static void close_current_inode(struct send_ctx *sctx) +{ + u64 i_size; + + if (sctx->cur_inode == NULL) + return; + + i_size = i_size_read(sctx->cur_inode); + + /* + * If we are doing an incremental send, we may have extents between the + * last processed extent and the i_size that have not been processed + * because they haven't changed but we may have read some of their pages + * through readahead, see the comments at send_extent_data(). + */ + if (sctx->clean_page_cache && sctx->page_cache_clear_start < i_size) + truncate_inode_pages_range(&sctx->cur_inode->i_data, + sctx->page_cache_clear_start, + round_up(i_size, PAGE_SIZE) - 1); + + iput(sctx->cur_inode); + sctx->cur_inode = NULL; +} + +static int changed_inode(struct send_ctx *sctx, + enum btrfs_compare_tree_result result) +{ + int ret = 0; + struct btrfs_key *key = sctx->cmp_key; + struct btrfs_inode_item *left_ii = NULL; + struct btrfs_inode_item *right_ii = NULL; + u64 left_gen = 0; + u64 right_gen = 0; + + close_current_inode(sctx); + + sctx->cur_ino = key->objectid; + sctx->cur_inode_new_gen = false; + sctx->cur_inode_last_extent = (u64)-1; + sctx->cur_inode_next_write_offset = 0; + sctx->ignore_cur_inode = false; + + /* + * Set send_progress to current inode. This will tell all get_cur_xxx + * functions that the current inode's refs are not updated yet. Later, + * when process_recorded_refs is finished, it is set to cur_ino + 1. + */ + sctx->send_progress = sctx->cur_ino; + + if (result == BTRFS_COMPARE_TREE_NEW || + result == BTRFS_COMPARE_TREE_CHANGED) { + left_ii = btrfs_item_ptr(sctx->left_path->nodes[0], + sctx->left_path->slots[0], + struct btrfs_inode_item); + left_gen = btrfs_inode_generation(sctx->left_path->nodes[0], + left_ii); + } else { + right_ii = btrfs_item_ptr(sctx->right_path->nodes[0], + sctx->right_path->slots[0], + struct btrfs_inode_item); + right_gen = btrfs_inode_generation(sctx->right_path->nodes[0], + right_ii); + } + if (result == BTRFS_COMPARE_TREE_CHANGED) { + right_ii = btrfs_item_ptr(sctx->right_path->nodes[0], + sctx->right_path->slots[0], + struct btrfs_inode_item); + + right_gen = btrfs_inode_generation(sctx->right_path->nodes[0], + right_ii); + + /* + * The cur_ino = root dir case is special here. We can't treat + * the inode as deleted+reused because it would generate a + * stream that tries to delete/mkdir the root dir. + */ + if (left_gen != right_gen && + sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) + sctx->cur_inode_new_gen = true; + } + + /* + * Normally we do not find inodes with a link count of zero (orphans) + * because the most common case is to create a snapshot and use it + * for a send operation. However other less common use cases involve + * using a subvolume and send it after turning it to RO mode just + * after deleting all hard links of a file while holding an open + * file descriptor against it or turning a RO snapshot into RW mode, + * keep an open file descriptor against a file, delete it and then + * turn the snapshot back to RO mode before using it for a send + * operation. The former is what the receiver operation does. + * Therefore, if we want to send these snapshots soon after they're + * received, we need to handle orphan inodes as well. Moreover, orphans + * can appear not only in the send snapshot but also in the parent + * snapshot. Here are several cases: + * + * Case 1: BTRFS_COMPARE_TREE_NEW + * | send snapshot | action + * -------------------------------- + * nlink | 0 | ignore + * + * Case 2: BTRFS_COMPARE_TREE_DELETED + * | parent snapshot | action + * ---------------------------------- + * nlink | 0 | as usual + * Note: No unlinks will be sent because there're no paths for it. + * + * Case 3: BTRFS_COMPARE_TREE_CHANGED + * | | parent snapshot | send snapshot | action + * ----------------------------------------------------------------------- + * subcase 1 | nlink | 0 | 0 | ignore + * subcase 2 | nlink | >0 | 0 | new_gen(deletion) + * subcase 3 | nlink | 0 | >0 | new_gen(creation) + * + */ + if (result == BTRFS_COMPARE_TREE_NEW) { + if (btrfs_inode_nlink(sctx->left_path->nodes[0], left_ii) == 0) { + sctx->ignore_cur_inode = true; + goto out; + } + sctx->cur_inode_gen = left_gen; + sctx->cur_inode_new = true; + sctx->cur_inode_deleted = false; + sctx->cur_inode_size = btrfs_inode_size( + sctx->left_path->nodes[0], left_ii); + sctx->cur_inode_mode = btrfs_inode_mode( + sctx->left_path->nodes[0], left_ii); + sctx->cur_inode_rdev = btrfs_inode_rdev( + sctx->left_path->nodes[0], left_ii); + if (sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) + ret = send_create_inode_if_needed(sctx); + } else if (result == BTRFS_COMPARE_TREE_DELETED) { + sctx->cur_inode_gen = right_gen; + sctx->cur_inode_new = false; + sctx->cur_inode_deleted = true; + sctx->cur_inode_size = btrfs_inode_size( + sctx->right_path->nodes[0], right_ii); + sctx->cur_inode_mode = btrfs_inode_mode( + sctx->right_path->nodes[0], right_ii); + } else if (result == BTRFS_COMPARE_TREE_CHANGED) { + u32 new_nlinks, old_nlinks; + + new_nlinks = btrfs_inode_nlink(sctx->left_path->nodes[0], left_ii); + old_nlinks = btrfs_inode_nlink(sctx->right_path->nodes[0], right_ii); + if (new_nlinks == 0 && old_nlinks == 0) { + sctx->ignore_cur_inode = true; + goto out; + } else if (new_nlinks == 0 || old_nlinks == 0) { + sctx->cur_inode_new_gen = 1; + } + /* + * We need to do some special handling in case the inode was + * reported as changed with a changed generation number. This + * means that the original inode was deleted and new inode + * reused the same inum. So we have to treat the old inode as + * deleted and the new one as new. + */ + if (sctx->cur_inode_new_gen) { + /* + * First, process the inode as if it was deleted. + */ + if (old_nlinks > 0) { + sctx->cur_inode_gen = right_gen; + sctx->cur_inode_new = false; + sctx->cur_inode_deleted = true; + sctx->cur_inode_size = btrfs_inode_size( + sctx->right_path->nodes[0], right_ii); + sctx->cur_inode_mode = btrfs_inode_mode( + sctx->right_path->nodes[0], right_ii); + ret = process_all_refs(sctx, + BTRFS_COMPARE_TREE_DELETED); + if (ret < 0) + goto out; + } + + /* + * Now process the inode as if it was new. + */ + if (new_nlinks > 0) { + sctx->cur_inode_gen = left_gen; + sctx->cur_inode_new = true; + sctx->cur_inode_deleted = false; + sctx->cur_inode_size = btrfs_inode_size( + sctx->left_path->nodes[0], + left_ii); + sctx->cur_inode_mode = btrfs_inode_mode( + sctx->left_path->nodes[0], + left_ii); + sctx->cur_inode_rdev = btrfs_inode_rdev( + sctx->left_path->nodes[0], + left_ii); + ret = send_create_inode_if_needed(sctx); + if (ret < 0) + goto out; + + ret = process_all_refs(sctx, BTRFS_COMPARE_TREE_NEW); + if (ret < 0) + goto out; + /* + * Advance send_progress now as we did not get + * into process_recorded_refs_if_needed in the + * new_gen case. + */ + sctx->send_progress = sctx->cur_ino + 1; + + /* + * Now process all extents and xattrs of the + * inode as if they were all new. + */ + ret = process_all_extents(sctx); + if (ret < 0) + goto out; + ret = process_all_new_xattrs(sctx); + if (ret < 0) + goto out; + } + } else { + sctx->cur_inode_gen = left_gen; + sctx->cur_inode_new = false; + sctx->cur_inode_new_gen = false; + sctx->cur_inode_deleted = false; + sctx->cur_inode_size = btrfs_inode_size( + sctx->left_path->nodes[0], left_ii); + sctx->cur_inode_mode = btrfs_inode_mode( + sctx->left_path->nodes[0], left_ii); + } + } + +out: + return ret; +} + +/* + * We have to process new refs before deleted refs, but compare_trees gives us + * the new and deleted refs mixed. To fix this, we record the new/deleted refs + * first and later process them in process_recorded_refs. + * For the cur_inode_new_gen case, we skip recording completely because + * changed_inode did already initiate processing of refs. The reason for this is + * that in this case, compare_tree actually compares the refs of 2 different + * inodes. To fix this, process_all_refs is used in changed_inode to handle all + * refs of the right tree as deleted and all refs of the left tree as new. + */ +static int changed_ref(struct send_ctx *sctx, + enum btrfs_compare_tree_result result) +{ + int ret = 0; + + if (sctx->cur_ino != sctx->cmp_key->objectid) { + inconsistent_snapshot_error(sctx, result, "reference"); + return -EIO; + } + + if (!sctx->cur_inode_new_gen && + sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) { + if (result == BTRFS_COMPARE_TREE_NEW) + ret = record_new_ref(sctx); + else if (result == BTRFS_COMPARE_TREE_DELETED) + ret = record_deleted_ref(sctx); + else if (result == BTRFS_COMPARE_TREE_CHANGED) + ret = record_changed_ref(sctx); + } + + return ret; +} + +/* + * Process new/deleted/changed xattrs. We skip processing in the + * cur_inode_new_gen case because changed_inode did already initiate processing + * of xattrs. The reason is the same as in changed_ref + */ +static int changed_xattr(struct send_ctx *sctx, + enum btrfs_compare_tree_result result) +{ + int ret = 0; + + if (sctx->cur_ino != sctx->cmp_key->objectid) { + inconsistent_snapshot_error(sctx, result, "xattr"); + return -EIO; + } + + if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) { + if (result == BTRFS_COMPARE_TREE_NEW) + ret = process_new_xattr(sctx); + else if (result == BTRFS_COMPARE_TREE_DELETED) + ret = process_deleted_xattr(sctx); + else if (result == BTRFS_COMPARE_TREE_CHANGED) + ret = process_changed_xattr(sctx); + } + + return ret; +} + +/* + * Process new/deleted/changed extents. We skip processing in the + * cur_inode_new_gen case because changed_inode did already initiate processing + * of extents. The reason is the same as in changed_ref + */ +static int changed_extent(struct send_ctx *sctx, + enum btrfs_compare_tree_result result) +{ + int ret = 0; + + /* + * We have found an extent item that changed without the inode item + * having changed. This can happen either after relocation (where the + * disk_bytenr of an extent item is replaced at + * relocation.c:replace_file_extents()) or after deduplication into a + * file in both the parent and send snapshots (where an extent item can + * get modified or replaced with a new one). Note that deduplication + * updates the inode item, but it only changes the iversion (sequence + * field in the inode item) of the inode, so if a file is deduplicated + * the same amount of times in both the parent and send snapshots, its + * iversion becomes the same in both snapshots, whence the inode item is + * the same on both snapshots. + */ + if (sctx->cur_ino != sctx->cmp_key->objectid) + return 0; + + if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) { + if (result != BTRFS_COMPARE_TREE_DELETED) + ret = process_extent(sctx, sctx->left_path, + sctx->cmp_key); + } + + return ret; +} + +static int changed_verity(struct send_ctx *sctx, enum btrfs_compare_tree_result result) +{ + int ret = 0; + + if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) { + if (result == BTRFS_COMPARE_TREE_NEW) + sctx->cur_inode_needs_verity = true; + } + return ret; +} + +static int dir_changed(struct send_ctx *sctx, u64 dir) +{ + u64 orig_gen, new_gen; + int ret; + + ret = get_inode_gen(sctx->send_root, dir, &new_gen); + if (ret) + return ret; + + ret = get_inode_gen(sctx->parent_root, dir, &orig_gen); + if (ret) + return ret; + + return (orig_gen != new_gen) ? 1 : 0; +} + +static int compare_refs(struct send_ctx *sctx, struct btrfs_path *path, + struct btrfs_key *key) +{ + struct btrfs_inode_extref *extref; + struct extent_buffer *leaf; + u64 dirid = 0, last_dirid = 0; + unsigned long ptr; + u32 item_size; + u32 cur_offset = 0; + int ref_name_len; + int ret = 0; + + /* Easy case, just check this one dirid */ + if (key->type == BTRFS_INODE_REF_KEY) { + dirid = key->offset; + + ret = dir_changed(sctx, dirid); + goto out; + } + + leaf = path->nodes[0]; + item_size = btrfs_item_size(leaf, path->slots[0]); + ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); + while (cur_offset < item_size) { + extref = (struct btrfs_inode_extref *)(ptr + + cur_offset); + dirid = btrfs_inode_extref_parent(leaf, extref); + ref_name_len = btrfs_inode_extref_name_len(leaf, extref); + cur_offset += ref_name_len + sizeof(*extref); + if (dirid == last_dirid) + continue; + ret = dir_changed(sctx, dirid); + if (ret) + break; + last_dirid = dirid; + } +out: + return ret; +} + +/* + * Updates compare related fields in sctx and simply forwards to the actual + * changed_xxx functions. + */ +static int changed_cb(struct btrfs_path *left_path, + struct btrfs_path *right_path, + struct btrfs_key *key, + enum btrfs_compare_tree_result result, + struct send_ctx *sctx) +{ + int ret = 0; + + /* + * We can not hold the commit root semaphore here. This is because in + * the case of sending and receiving to the same filesystem, using a + * pipe, could result in a deadlock: + * + * 1) The task running send blocks on the pipe because it's full; + * + * 2) The task running receive, which is the only consumer of the pipe, + * is waiting for a transaction commit (for example due to a space + * reservation when doing a write or triggering a transaction commit + * when creating a subvolume); + * + * 3) The transaction is waiting to write lock the commit root semaphore, + * but can not acquire it since it's being held at 1). + * + * Down this call chain we write to the pipe through kernel_write(). + * The same type of problem can also happen when sending to a file that + * is stored in the same filesystem - when reserving space for a write + * into the file, we can trigger a transaction commit. + * + * Our caller has supplied us with clones of leaves from the send and + * parent roots, so we're safe here from a concurrent relocation and + * further reallocation of metadata extents while we are here. Below we + * also assert that the leaves are clones. + */ + lockdep_assert_not_held(&sctx->send_root->fs_info->commit_root_sem); + + /* + * We always have a send root, so left_path is never NULL. We will not + * have a leaf when we have reached the end of the send root but have + * not yet reached the end of the parent root. + */ + if (left_path->nodes[0]) + ASSERT(test_bit(EXTENT_BUFFER_UNMAPPED, + &left_path->nodes[0]->bflags)); + /* + * When doing a full send we don't have a parent root, so right_path is + * NULL. When doing an incremental send, we may have reached the end of + * the parent root already, so we don't have a leaf at right_path. + */ + if (right_path && right_path->nodes[0]) + ASSERT(test_bit(EXTENT_BUFFER_UNMAPPED, + &right_path->nodes[0]->bflags)); + + if (result == BTRFS_COMPARE_TREE_SAME) { + if (key->type == BTRFS_INODE_REF_KEY || + key->type == BTRFS_INODE_EXTREF_KEY) { + ret = compare_refs(sctx, left_path, key); + if (!ret) + return 0; + if (ret < 0) + return ret; + } else if (key->type == BTRFS_EXTENT_DATA_KEY) { + return maybe_send_hole(sctx, left_path, key); + } else { + return 0; + } + result = BTRFS_COMPARE_TREE_CHANGED; + ret = 0; + } + + sctx->left_path = left_path; + sctx->right_path = right_path; + sctx->cmp_key = key; + + ret = finish_inode_if_needed(sctx, 0); + if (ret < 0) + goto out; + + /* Ignore non-FS objects */ + if (key->objectid == BTRFS_FREE_INO_OBJECTID || + key->objectid == BTRFS_FREE_SPACE_OBJECTID) + goto out; + + if (key->type == BTRFS_INODE_ITEM_KEY) { + ret = changed_inode(sctx, result); + } else if (!sctx->ignore_cur_inode) { + if (key->type == BTRFS_INODE_REF_KEY || + key->type == BTRFS_INODE_EXTREF_KEY) + ret = changed_ref(sctx, result); + else if (key->type == BTRFS_XATTR_ITEM_KEY) + ret = changed_xattr(sctx, result); + else if (key->type == BTRFS_EXTENT_DATA_KEY) + ret = changed_extent(sctx, result); + else if (key->type == BTRFS_VERITY_DESC_ITEM_KEY && + key->offset == 0) + ret = changed_verity(sctx, result); + } + +out: + return ret; +} + +static int search_key_again(const struct send_ctx *sctx, + struct btrfs_root *root, + struct btrfs_path *path, + const struct btrfs_key *key) +{ + int ret; + + if (!path->need_commit_sem) + lockdep_assert_held_read(&root->fs_info->commit_root_sem); + + /* + * Roots used for send operations are readonly and no one can add, + * update or remove keys from them, so we should be able to find our + * key again. The only exception is deduplication, which can operate on + * readonly roots and add, update or remove keys to/from them - but at + * the moment we don't allow it to run in parallel with send. + */ + ret = btrfs_search_slot(NULL, root, key, path, 0, 0); + ASSERT(ret <= 0); + if (ret > 0) { + btrfs_print_tree(path->nodes[path->lowest_level], false); + btrfs_err(root->fs_info, +"send: key (%llu %u %llu) not found in %s root %llu, lowest_level %d, slot %d", + key->objectid, key->type, key->offset, + (root == sctx->parent_root ? "parent" : "send"), + root->root_key.objectid, path->lowest_level, + path->slots[path->lowest_level]); + return -EUCLEAN; + } + + return ret; +} + +static int full_send_tree(struct send_ctx *sctx) +{ + int ret; + struct btrfs_root *send_root = sctx->send_root; + struct btrfs_key key; + struct btrfs_fs_info *fs_info = send_root->fs_info; + struct btrfs_path *path; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + path->reada = READA_FORWARD_ALWAYS; + + key.objectid = BTRFS_FIRST_FREE_OBJECTID; + key.type = BTRFS_INODE_ITEM_KEY; + key.offset = 0; + + down_read(&fs_info->commit_root_sem); + sctx->last_reloc_trans = fs_info->last_reloc_trans; + up_read(&fs_info->commit_root_sem); + + ret = btrfs_search_slot_for_read(send_root, &key, path, 1, 0); + if (ret < 0) + goto out; + if (ret) + goto out_finish; + + while (1) { + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); + + ret = changed_cb(path, NULL, &key, + BTRFS_COMPARE_TREE_NEW, sctx); + if (ret < 0) + goto out; + + down_read(&fs_info->commit_root_sem); + if (fs_info->last_reloc_trans > sctx->last_reloc_trans) { + sctx->last_reloc_trans = fs_info->last_reloc_trans; + up_read(&fs_info->commit_root_sem); + /* + * A transaction used for relocating a block group was + * committed or is about to finish its commit. Release + * our path (leaf) and restart the search, so that we + * avoid operating on any file extent items that are + * stale, with a disk_bytenr that reflects a pre + * relocation value. This way we avoid as much as + * possible to fallback to regular writes when checking + * if we can clone file ranges. + */ + btrfs_release_path(path); + ret = search_key_again(sctx, send_root, path, &key); + if (ret < 0) + goto out; + } else { + up_read(&fs_info->commit_root_sem); + } + + ret = btrfs_next_item(send_root, path); + if (ret < 0) + goto out; + if (ret) { + ret = 0; + break; + } + } + +out_finish: + ret = finish_inode_if_needed(sctx, 1); + +out: + btrfs_free_path(path); + return ret; +} + +static int replace_node_with_clone(struct btrfs_path *path, int level) +{ + struct extent_buffer *clone; + + clone = btrfs_clone_extent_buffer(path->nodes[level]); + if (!clone) + return -ENOMEM; + + free_extent_buffer(path->nodes[level]); + path->nodes[level] = clone; + + return 0; +} + +static int tree_move_down(struct btrfs_path *path, int *level, u64 reada_min_gen) +{ + struct extent_buffer *eb; + struct extent_buffer *parent = path->nodes[*level]; + int slot = path->slots[*level]; + const int nritems = btrfs_header_nritems(parent); + u64 reada_max; + u64 reada_done = 0; + + lockdep_assert_held_read(&parent->fs_info->commit_root_sem); + + BUG_ON(*level == 0); + eb = btrfs_read_node_slot(parent, slot); + if (IS_ERR(eb)) + return PTR_ERR(eb); + + /* + * Trigger readahead for the next leaves we will process, so that it is + * very likely that when we need them they are already in memory and we + * will not block on disk IO. For nodes we only do readahead for one, + * since the time window between processing nodes is typically larger. + */ + reada_max = (*level == 1 ? SZ_128K : eb->fs_info->nodesize); + + for (slot++; slot < nritems && reada_done < reada_max; slot++) { + if (btrfs_node_ptr_generation(parent, slot) > reada_min_gen) { + btrfs_readahead_node_child(parent, slot); + reada_done += eb->fs_info->nodesize; + } + } + + path->nodes[*level - 1] = eb; + path->slots[*level - 1] = 0; + (*level)--; + + if (*level == 0) + return replace_node_with_clone(path, 0); + + return 0; +} + +static int tree_move_next_or_upnext(struct btrfs_path *path, + int *level, int root_level) +{ + int ret = 0; + int nritems; + nritems = btrfs_header_nritems(path->nodes[*level]); + + path->slots[*level]++; + + while (path->slots[*level] >= nritems) { + if (*level == root_level) { + path->slots[*level] = nritems - 1; + return -1; + } + + /* move upnext */ + path->slots[*level] = 0; + free_extent_buffer(path->nodes[*level]); + path->nodes[*level] = NULL; + (*level)++; + path->slots[*level]++; + + nritems = btrfs_header_nritems(path->nodes[*level]); + ret = 1; + } + return ret; +} + +/* + * Returns 1 if it had to move up and next. 0 is returned if it moved only next + * or down. + */ +static int tree_advance(struct btrfs_path *path, + int *level, int root_level, + int allow_down, + struct btrfs_key *key, + u64 reada_min_gen) +{ + int ret; + + if (*level == 0 || !allow_down) { + ret = tree_move_next_or_upnext(path, level, root_level); + } else { + ret = tree_move_down(path, level, reada_min_gen); + } + + /* + * Even if we have reached the end of a tree, ret is -1, update the key + * anyway, so that in case we need to restart due to a block group + * relocation, we can assert that the last key of the root node still + * exists in the tree. + */ + if (*level == 0) + btrfs_item_key_to_cpu(path->nodes[*level], key, + path->slots[*level]); + else + btrfs_node_key_to_cpu(path->nodes[*level], key, + path->slots[*level]); + + return ret; +} + +static int tree_compare_item(struct btrfs_path *left_path, + struct btrfs_path *right_path, + char *tmp_buf) +{ + int cmp; + int len1, len2; + unsigned long off1, off2; + + len1 = btrfs_item_size(left_path->nodes[0], left_path->slots[0]); + len2 = btrfs_item_size(right_path->nodes[0], right_path->slots[0]); + if (len1 != len2) + return 1; + + off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]); + off2 = btrfs_item_ptr_offset(right_path->nodes[0], + right_path->slots[0]); + + read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1); + + cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1); + if (cmp) + return 1; + return 0; +} + +/* + * A transaction used for relocating a block group was committed or is about to + * finish its commit. Release our paths and restart the search, so that we are + * not using stale extent buffers: + * + * 1) For levels > 0, we are only holding references of extent buffers, without + * any locks on them, which does not prevent them from having been relocated + * and reallocated after the last time we released the commit root semaphore. + * The exception are the root nodes, for which we always have a clone, see + * the comment at btrfs_compare_trees(); + * + * 2) For leaves, level 0, we are holding copies (clones) of extent buffers, so + * we are safe from the concurrent relocation and reallocation. However they + * can have file extent items with a pre relocation disk_bytenr value, so we + * restart the start from the current commit roots and clone the new leaves so + * that we get the post relocation disk_bytenr values. Not doing so, could + * make us clone the wrong data in case there are new extents using the old + * disk_bytenr that happen to be shared. + */ +static int restart_after_relocation(struct btrfs_path *left_path, + struct btrfs_path *right_path, + const struct btrfs_key *left_key, + const struct btrfs_key *right_key, + int left_level, + int right_level, + const struct send_ctx *sctx) +{ + int root_level; + int ret; + + lockdep_assert_held_read(&sctx->send_root->fs_info->commit_root_sem); + + btrfs_release_path(left_path); + btrfs_release_path(right_path); + + /* + * Since keys can not be added or removed to/from our roots because they + * are readonly and we do not allow deduplication to run in parallel + * (which can add, remove or change keys), the layout of the trees should + * not change. + */ + left_path->lowest_level = left_level; + ret = search_key_again(sctx, sctx->send_root, left_path, left_key); + if (ret < 0) + return ret; + + right_path->lowest_level = right_level; + ret = search_key_again(sctx, sctx->parent_root, right_path, right_key); + if (ret < 0) + return ret; + + /* + * If the lowest level nodes are leaves, clone them so that they can be + * safely used by changed_cb() while not under the protection of the + * commit root semaphore, even if relocation and reallocation happens in + * parallel. + */ + if (left_level == 0) { + ret = replace_node_with_clone(left_path, 0); + if (ret < 0) + return ret; + } + + if (right_level == 0) { + ret = replace_node_with_clone(right_path, 0); + if (ret < 0) + return ret; + } + + /* + * Now clone the root nodes (unless they happen to be the leaves we have + * already cloned). This is to protect against concurrent snapshotting of + * the send and parent roots (see the comment at btrfs_compare_trees()). + */ + root_level = btrfs_header_level(sctx->send_root->commit_root); + if (root_level > 0) { + ret = replace_node_with_clone(left_path, root_level); + if (ret < 0) + return ret; + } + + root_level = btrfs_header_level(sctx->parent_root->commit_root); + if (root_level > 0) { + ret = replace_node_with_clone(right_path, root_level); + if (ret < 0) + return ret; + } + + return 0; +} + +/* + * This function compares two trees and calls the provided callback for + * every changed/new/deleted item it finds. + * If shared tree blocks are encountered, whole subtrees are skipped, making + * the compare pretty fast on snapshotted subvolumes. + * + * This currently works on commit roots only. As commit roots are read only, + * we don't do any locking. The commit roots are protected with transactions. + * Transactions are ended and rejoined when a commit is tried in between. + * + * This function checks for modifications done to the trees while comparing. + * If it detects a change, it aborts immediately. + */ +static int btrfs_compare_trees(struct btrfs_root *left_root, + struct btrfs_root *right_root, struct send_ctx *sctx) +{ + struct btrfs_fs_info *fs_info = left_root->fs_info; + int ret; + int cmp; + struct btrfs_path *left_path = NULL; + struct btrfs_path *right_path = NULL; + struct btrfs_key left_key; + struct btrfs_key right_key; + char *tmp_buf = NULL; + int left_root_level; + int right_root_level; + int left_level; + int right_level; + int left_end_reached = 0; + int right_end_reached = 0; + int advance_left = 0; + int advance_right = 0; + u64 left_blockptr; + u64 right_blockptr; + u64 left_gen; + u64 right_gen; + u64 reada_min_gen; + + left_path = btrfs_alloc_path(); + if (!left_path) { + ret = -ENOMEM; + goto out; + } + right_path = btrfs_alloc_path(); + if (!right_path) { + ret = -ENOMEM; + goto out; + } + + tmp_buf = kvmalloc(fs_info->nodesize, GFP_KERNEL); + if (!tmp_buf) { + ret = -ENOMEM; + goto out; + } + + left_path->search_commit_root = 1; + left_path->skip_locking = 1; + right_path->search_commit_root = 1; + right_path->skip_locking = 1; + + /* + * Strategy: Go to the first items of both trees. Then do + * + * If both trees are at level 0 + * Compare keys of current items + * If left < right treat left item as new, advance left tree + * and repeat + * If left > right treat right item as deleted, advance right tree + * and repeat + * If left == right do deep compare of items, treat as changed if + * needed, advance both trees and repeat + * If both trees are at the same level but not at level 0 + * Compare keys of current nodes/leafs + * If left < right advance left tree and repeat + * If left > right advance right tree and repeat + * If left == right compare blockptrs of the next nodes/leafs + * If they match advance both trees but stay at the same level + * and repeat + * If they don't match advance both trees while allowing to go + * deeper and repeat + * If tree levels are different + * Advance the tree that needs it and repeat + * + * Advancing a tree means: + * If we are at level 0, try to go to the next slot. If that's not + * possible, go one level up and repeat. Stop when we found a level + * where we could go to the next slot. We may at this point be on a + * node or a leaf. + * + * If we are not at level 0 and not on shared tree blocks, go one + * level deeper. + * + * If we are not at level 0 and on shared tree blocks, go one slot to + * the right if possible or go up and right. + */ + + down_read(&fs_info->commit_root_sem); + left_level = btrfs_header_level(left_root->commit_root); + left_root_level = left_level; + /* + * We clone the root node of the send and parent roots to prevent races + * with snapshot creation of these roots. Snapshot creation COWs the + * root node of a tree, so after the transaction is committed the old + * extent can be reallocated while this send operation is still ongoing. + * So we clone them, under the commit root semaphore, to be race free. + */ + left_path->nodes[left_level] = + btrfs_clone_extent_buffer(left_root->commit_root); + if (!left_path->nodes[left_level]) { + ret = -ENOMEM; + goto out_unlock; + } + + right_level = btrfs_header_level(right_root->commit_root); + right_root_level = right_level; + right_path->nodes[right_level] = + btrfs_clone_extent_buffer(right_root->commit_root); + if (!right_path->nodes[right_level]) { + ret = -ENOMEM; + goto out_unlock; + } + /* + * Our right root is the parent root, while the left root is the "send" + * root. We know that all new nodes/leaves in the left root must have + * a generation greater than the right root's generation, so we trigger + * readahead for those nodes and leaves of the left root, as we know we + * will need to read them at some point. + */ + reada_min_gen = btrfs_header_generation(right_root->commit_root); + + if (left_level == 0) + btrfs_item_key_to_cpu(left_path->nodes[left_level], + &left_key, left_path->slots[left_level]); + else + btrfs_node_key_to_cpu(left_path->nodes[left_level], + &left_key, left_path->slots[left_level]); + if (right_level == 0) + btrfs_item_key_to_cpu(right_path->nodes[right_level], + &right_key, right_path->slots[right_level]); + else + btrfs_node_key_to_cpu(right_path->nodes[right_level], + &right_key, right_path->slots[right_level]); + + sctx->last_reloc_trans = fs_info->last_reloc_trans; + + while (1) { + if (need_resched() || + rwsem_is_contended(&fs_info->commit_root_sem)) { + up_read(&fs_info->commit_root_sem); + cond_resched(); + down_read(&fs_info->commit_root_sem); + } + + if (fs_info->last_reloc_trans > sctx->last_reloc_trans) { + ret = restart_after_relocation(left_path, right_path, + &left_key, &right_key, + left_level, right_level, + sctx); + if (ret < 0) + goto out_unlock; + sctx->last_reloc_trans = fs_info->last_reloc_trans; + } + + if (advance_left && !left_end_reached) { + ret = tree_advance(left_path, &left_level, + left_root_level, + advance_left != ADVANCE_ONLY_NEXT, + &left_key, reada_min_gen); + if (ret == -1) + left_end_reached = ADVANCE; + else if (ret < 0) + goto out_unlock; + advance_left = 0; + } + if (advance_right && !right_end_reached) { + ret = tree_advance(right_path, &right_level, + right_root_level, + advance_right != ADVANCE_ONLY_NEXT, + &right_key, reada_min_gen); + if (ret == -1) + right_end_reached = ADVANCE; + else if (ret < 0) + goto out_unlock; + advance_right = 0; + } + + if (left_end_reached && right_end_reached) { + ret = 0; + goto out_unlock; + } else if (left_end_reached) { + if (right_level == 0) { + up_read(&fs_info->commit_root_sem); + ret = changed_cb(left_path, right_path, + &right_key, + BTRFS_COMPARE_TREE_DELETED, + sctx); + if (ret < 0) + goto out; + down_read(&fs_info->commit_root_sem); + } + advance_right = ADVANCE; + continue; + } else if (right_end_reached) { + if (left_level == 0) { + up_read(&fs_info->commit_root_sem); + ret = changed_cb(left_path, right_path, + &left_key, + BTRFS_COMPARE_TREE_NEW, + sctx); + if (ret < 0) + goto out; + down_read(&fs_info->commit_root_sem); + } + advance_left = ADVANCE; + continue; + } + + if (left_level == 0 && right_level == 0) { + up_read(&fs_info->commit_root_sem); + cmp = btrfs_comp_cpu_keys(&left_key, &right_key); + if (cmp < 0) { + ret = changed_cb(left_path, right_path, + &left_key, + BTRFS_COMPARE_TREE_NEW, + sctx); + advance_left = ADVANCE; + } else if (cmp > 0) { + ret = changed_cb(left_path, right_path, + &right_key, + BTRFS_COMPARE_TREE_DELETED, + sctx); + advance_right = ADVANCE; + } else { + enum btrfs_compare_tree_result result; + + WARN_ON(!extent_buffer_uptodate(left_path->nodes[0])); + ret = tree_compare_item(left_path, right_path, + tmp_buf); + if (ret) + result = BTRFS_COMPARE_TREE_CHANGED; + else + result = BTRFS_COMPARE_TREE_SAME; + ret = changed_cb(left_path, right_path, + &left_key, result, sctx); + advance_left = ADVANCE; + advance_right = ADVANCE; + } + + if (ret < 0) + goto out; + down_read(&fs_info->commit_root_sem); + } else if (left_level == right_level) { + cmp = btrfs_comp_cpu_keys(&left_key, &right_key); + if (cmp < 0) { + advance_left = ADVANCE; + } else if (cmp > 0) { + advance_right = ADVANCE; + } else { + left_blockptr = btrfs_node_blockptr( + left_path->nodes[left_level], + left_path->slots[left_level]); + right_blockptr = btrfs_node_blockptr( + right_path->nodes[right_level], + right_path->slots[right_level]); + left_gen = btrfs_node_ptr_generation( + left_path->nodes[left_level], + left_path->slots[left_level]); + right_gen = btrfs_node_ptr_generation( + right_path->nodes[right_level], + right_path->slots[right_level]); + if (left_blockptr == right_blockptr && + left_gen == right_gen) { + /* + * As we're on a shared block, don't + * allow to go deeper. + */ + advance_left = ADVANCE_ONLY_NEXT; + advance_right = ADVANCE_ONLY_NEXT; + } else { + advance_left = ADVANCE; + advance_right = ADVANCE; + } + } + } else if (left_level < right_level) { + advance_right = ADVANCE; + } else { + advance_left = ADVANCE; + } + } + +out_unlock: + up_read(&fs_info->commit_root_sem); +out: + btrfs_free_path(left_path); + btrfs_free_path(right_path); + kvfree(tmp_buf); + return ret; +} + +static int send_subvol(struct send_ctx *sctx) +{ + int ret; + + if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_STREAM_HEADER)) { + ret = send_header(sctx); + if (ret < 0) + goto out; + } + + ret = send_subvol_begin(sctx); + if (ret < 0) + goto out; + + if (sctx->parent_root) { + ret = btrfs_compare_trees(sctx->send_root, sctx->parent_root, sctx); + if (ret < 0) + goto out; + ret = finish_inode_if_needed(sctx, 1); + if (ret < 0) + goto out; + } else { + ret = full_send_tree(sctx); + if (ret < 0) + goto out; + } + +out: + free_recorded_refs(sctx); + return ret; +} + +/* + * If orphan cleanup did remove any orphans from a root, it means the tree + * was modified and therefore the commit root is not the same as the current + * root anymore. This is a problem, because send uses the commit root and + * therefore can see inode items that don't exist in the current root anymore, + * and for example make calls to btrfs_iget, which will do tree lookups based + * on the current root and not on the commit root. Those lookups will fail, + * returning a -ESTALE error, and making send fail with that error. So make + * sure a send does not see any orphans we have just removed, and that it will + * see the same inodes regardless of whether a transaction commit happened + * before it started (meaning that the commit root will be the same as the + * current root) or not. + */ +static int ensure_commit_roots_uptodate(struct send_ctx *sctx) +{ + int i; + struct btrfs_trans_handle *trans = NULL; + +again: + if (sctx->parent_root && + sctx->parent_root->node != sctx->parent_root->commit_root) + goto commit_trans; + + for (i = 0; i < sctx->clone_roots_cnt; i++) + if (sctx->clone_roots[i].root->node != + sctx->clone_roots[i].root->commit_root) + goto commit_trans; + + if (trans) + return btrfs_end_transaction(trans); + + return 0; + +commit_trans: + /* Use any root, all fs roots will get their commit roots updated. */ + if (!trans) { + trans = btrfs_join_transaction(sctx->send_root); + if (IS_ERR(trans)) + return PTR_ERR(trans); + goto again; + } + + return btrfs_commit_transaction(trans); +} + +/* + * Make sure any existing dellaloc is flushed for any root used by a send + * operation so that we do not miss any data and we do not race with writeback + * finishing and changing a tree while send is using the tree. This could + * happen if a subvolume is in RW mode, has delalloc, is turned to RO mode and + * a send operation then uses the subvolume. + * After flushing delalloc ensure_commit_roots_uptodate() must be called. + */ +static int flush_delalloc_roots(struct send_ctx *sctx) +{ + struct btrfs_root *root = sctx->parent_root; + int ret; + int i; + + if (root) { + ret = btrfs_start_delalloc_snapshot(root, false); + if (ret) + return ret; + btrfs_wait_ordered_extents(root, U64_MAX, 0, U64_MAX); + } + + for (i = 0; i < sctx->clone_roots_cnt; i++) { + root = sctx->clone_roots[i].root; + ret = btrfs_start_delalloc_snapshot(root, false); + if (ret) + return ret; + btrfs_wait_ordered_extents(root, U64_MAX, 0, U64_MAX); + } + + return 0; +} + +static void btrfs_root_dec_send_in_progress(struct btrfs_root* root) +{ + spin_lock(&root->root_item_lock); + root->send_in_progress--; + /* + * Not much left to do, we don't know why it's unbalanced and + * can't blindly reset it to 0. + */ + if (root->send_in_progress < 0) + btrfs_err(root->fs_info, + "send_in_progress unbalanced %d root %llu", + root->send_in_progress, root->root_key.objectid); + spin_unlock(&root->root_item_lock); +} + +static void dedupe_in_progress_warn(const struct btrfs_root *root) +{ + btrfs_warn_rl(root->fs_info, +"cannot use root %llu for send while deduplications on it are in progress (%d in progress)", + root->root_key.objectid, root->dedupe_in_progress); +} + +long btrfs_ioctl_send(struct inode *inode, struct btrfs_ioctl_send_args *arg) +{ + int ret = 0; + struct btrfs_root *send_root = BTRFS_I(inode)->root; + struct btrfs_fs_info *fs_info = send_root->fs_info; + struct btrfs_root *clone_root; + struct send_ctx *sctx = NULL; + u32 i; + u64 *clone_sources_tmp = NULL; + int clone_sources_to_rollback = 0; + size_t alloc_size; + int sort_clone_roots = 0; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + /* + * The subvolume must remain read-only during send, protect against + * making it RW. This also protects against deletion. + */ + spin_lock(&send_root->root_item_lock); + if (btrfs_root_readonly(send_root) && send_root->dedupe_in_progress) { + dedupe_in_progress_warn(send_root); + spin_unlock(&send_root->root_item_lock); + return -EAGAIN; + } + send_root->send_in_progress++; + spin_unlock(&send_root->root_item_lock); + + /* + * Userspace tools do the checks and warn the user if it's + * not RO. + */ + if (!btrfs_root_readonly(send_root)) { + ret = -EPERM; + goto out; + } + + /* + * Check that we don't overflow at later allocations, we request + * clone_sources_count + 1 items, and compare to unsigned long inside + * access_ok. Also set an upper limit for allocation size so this can't + * easily exhaust memory. Max number of clone sources is about 200K. + */ + if (arg->clone_sources_count > SZ_8M / sizeof(struct clone_root)) { + ret = -EINVAL; + goto out; + } + + if (arg->flags & ~BTRFS_SEND_FLAG_MASK) { + ret = -EINVAL; + goto out; + } + + sctx = kzalloc(sizeof(struct send_ctx), GFP_KERNEL); + if (!sctx) { + ret = -ENOMEM; + goto out; + } + + INIT_LIST_HEAD(&sctx->new_refs); + INIT_LIST_HEAD(&sctx->deleted_refs); + INIT_RADIX_TREE(&sctx->name_cache, GFP_KERNEL); + INIT_LIST_HEAD(&sctx->name_cache_list); + + sctx->flags = arg->flags; + + if (arg->flags & BTRFS_SEND_FLAG_VERSION) { + if (arg->version > BTRFS_SEND_STREAM_VERSION) { + ret = -EPROTO; + goto out; + } + /* Zero means "use the highest version" */ + sctx->proto = arg->version ?: BTRFS_SEND_STREAM_VERSION; + } else { + sctx->proto = 1; + } + if ((arg->flags & BTRFS_SEND_FLAG_COMPRESSED) && sctx->proto < 2) { + ret = -EINVAL; + goto out; + } + + sctx->send_filp = fget(arg->send_fd); + if (!sctx->send_filp || !(sctx->send_filp->f_mode & FMODE_WRITE)) { + ret = -EBADF; + goto out; + } + + sctx->send_root = send_root; + /* + * Unlikely but possible, if the subvolume is marked for deletion but + * is slow to remove the directory entry, send can still be started + */ + if (btrfs_root_dead(sctx->send_root)) { + ret = -EPERM; + goto out; + } + + sctx->clone_roots_cnt = arg->clone_sources_count; + + if (sctx->proto >= 2) { + u32 send_buf_num_pages; + + sctx->send_max_size = ALIGN(SZ_16K + BTRFS_MAX_COMPRESSED, PAGE_SIZE); + sctx->send_buf = vmalloc(sctx->send_max_size); + if (!sctx->send_buf) { + ret = -ENOMEM; + goto out; + } + send_buf_num_pages = sctx->send_max_size >> PAGE_SHIFT; + sctx->send_buf_pages = kcalloc(send_buf_num_pages, + sizeof(*sctx->send_buf_pages), + GFP_KERNEL); + if (!sctx->send_buf_pages) { + ret = -ENOMEM; + goto out; + } + for (i = 0; i < send_buf_num_pages; i++) { + sctx->send_buf_pages[i] = + vmalloc_to_page(sctx->send_buf + (i << PAGE_SHIFT)); + } + } else { + sctx->send_max_size = BTRFS_SEND_BUF_SIZE_V1; + sctx->send_buf = kvmalloc(sctx->send_max_size, GFP_KERNEL); + } + if (!sctx->send_buf) { + ret = -ENOMEM; + goto out; + } + + sctx->pending_dir_moves = RB_ROOT; + sctx->waiting_dir_moves = RB_ROOT; + sctx->orphan_dirs = RB_ROOT; + sctx->rbtree_new_refs = RB_ROOT; + sctx->rbtree_deleted_refs = RB_ROOT; + + sctx->clone_roots = kvcalloc(sizeof(*sctx->clone_roots), + arg->clone_sources_count + 1, + GFP_KERNEL); + if (!sctx->clone_roots) { + ret = -ENOMEM; + goto out; + } + + alloc_size = array_size(sizeof(*arg->clone_sources), + arg->clone_sources_count); + + if (arg->clone_sources_count) { + clone_sources_tmp = kvmalloc(alloc_size, GFP_KERNEL); + if (!clone_sources_tmp) { + ret = -ENOMEM; + goto out; + } + + ret = copy_from_user(clone_sources_tmp, arg->clone_sources, + alloc_size); + if (ret) { + ret = -EFAULT; + goto out; + } + + for (i = 0; i < arg->clone_sources_count; i++) { + clone_root = btrfs_get_fs_root(fs_info, + clone_sources_tmp[i], true); + if (IS_ERR(clone_root)) { + ret = PTR_ERR(clone_root); + goto out; + } + spin_lock(&clone_root->root_item_lock); + if (!btrfs_root_readonly(clone_root) || + btrfs_root_dead(clone_root)) { + spin_unlock(&clone_root->root_item_lock); + btrfs_put_root(clone_root); + ret = -EPERM; + goto out; + } + if (clone_root->dedupe_in_progress) { + dedupe_in_progress_warn(clone_root); + spin_unlock(&clone_root->root_item_lock); + btrfs_put_root(clone_root); + ret = -EAGAIN; + goto out; + } + clone_root->send_in_progress++; + spin_unlock(&clone_root->root_item_lock); + + sctx->clone_roots[i].root = clone_root; + clone_sources_to_rollback = i + 1; + } + kvfree(clone_sources_tmp); + clone_sources_tmp = NULL; + } + + if (arg->parent_root) { + sctx->parent_root = btrfs_get_fs_root(fs_info, arg->parent_root, + true); + if (IS_ERR(sctx->parent_root)) { + ret = PTR_ERR(sctx->parent_root); + goto out; + } + + spin_lock(&sctx->parent_root->root_item_lock); + sctx->parent_root->send_in_progress++; + if (!btrfs_root_readonly(sctx->parent_root) || + btrfs_root_dead(sctx->parent_root)) { + spin_unlock(&sctx->parent_root->root_item_lock); + ret = -EPERM; + goto out; + } + if (sctx->parent_root->dedupe_in_progress) { + dedupe_in_progress_warn(sctx->parent_root); + spin_unlock(&sctx->parent_root->root_item_lock); + ret = -EAGAIN; + goto out; + } + spin_unlock(&sctx->parent_root->root_item_lock); + } + + /* + * Clones from send_root are allowed, but only if the clone source + * is behind the current send position. This is checked while searching + * for possible clone sources. + */ + sctx->clone_roots[sctx->clone_roots_cnt++].root = + btrfs_grab_root(sctx->send_root); + + /* We do a bsearch later */ + sort(sctx->clone_roots, sctx->clone_roots_cnt, + sizeof(*sctx->clone_roots), __clone_root_cmp_sort, + NULL); + sort_clone_roots = 1; + + ret = flush_delalloc_roots(sctx); + if (ret) + goto out; + + ret = ensure_commit_roots_uptodate(sctx); + if (ret) + goto out; + + ret = send_subvol(sctx); + if (ret < 0) + goto out; + + if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_END_CMD)) { + ret = begin_cmd(sctx, BTRFS_SEND_C_END); + if (ret < 0) + goto out; + ret = send_cmd(sctx); + if (ret < 0) + goto out; + } + +out: + WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->pending_dir_moves)); + while (sctx && !RB_EMPTY_ROOT(&sctx->pending_dir_moves)) { + struct rb_node *n; + struct pending_dir_move *pm; + + n = rb_first(&sctx->pending_dir_moves); + pm = rb_entry(n, struct pending_dir_move, node); + while (!list_empty(&pm->list)) { + struct pending_dir_move *pm2; + + pm2 = list_first_entry(&pm->list, + struct pending_dir_move, list); + free_pending_move(sctx, pm2); + } + free_pending_move(sctx, pm); + } + + WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves)); + while (sctx && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves)) { + struct rb_node *n; + struct waiting_dir_move *dm; + + n = rb_first(&sctx->waiting_dir_moves); + dm = rb_entry(n, struct waiting_dir_move, node); + rb_erase(&dm->node, &sctx->waiting_dir_moves); + kfree(dm); + } + + WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->orphan_dirs)); + while (sctx && !RB_EMPTY_ROOT(&sctx->orphan_dirs)) { + struct rb_node *n; + struct orphan_dir_info *odi; + + n = rb_first(&sctx->orphan_dirs); + odi = rb_entry(n, struct orphan_dir_info, node); + free_orphan_dir_info(sctx, odi); + } + + if (sort_clone_roots) { + for (i = 0; i < sctx->clone_roots_cnt; i++) { + btrfs_root_dec_send_in_progress( + sctx->clone_roots[i].root); + btrfs_put_root(sctx->clone_roots[i].root); + } + } else { + for (i = 0; sctx && i < clone_sources_to_rollback; i++) { + btrfs_root_dec_send_in_progress( + sctx->clone_roots[i].root); + btrfs_put_root(sctx->clone_roots[i].root); + } + + btrfs_root_dec_send_in_progress(send_root); + } + if (sctx && !IS_ERR_OR_NULL(sctx->parent_root)) { + btrfs_root_dec_send_in_progress(sctx->parent_root); + btrfs_put_root(sctx->parent_root); + } + + kvfree(clone_sources_tmp); + + if (sctx) { + if (sctx->send_filp) + fput(sctx->send_filp); + + kvfree(sctx->clone_roots); + kfree(sctx->send_buf_pages); + kvfree(sctx->send_buf); + kvfree(sctx->verity_descriptor); + + name_cache_free(sctx); + + close_current_inode(sctx); + + kfree(sctx); + } + + return ret; +} |