diff options
Diffstat (limited to 'fs/btrfs/file.c')
| -rw-r--r-- | fs/btrfs/file.c | 3856 |
1 files changed, 3856 insertions, 0 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c new file mode 100644 index 000000000..1783a0fbf --- /dev/null +++ b/fs/btrfs/file.c @@ -0,0 +1,3856 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2007 Oracle. All rights reserved. + */ + +#include <linux/fs.h> +#include <linux/pagemap.h> +#include <linux/time.h> +#include <linux/init.h> +#include <linux/string.h> +#include <linux/backing-dev.h> +#include <linux/falloc.h> +#include <linux/writeback.h> +#include <linux/compat.h> +#include <linux/slab.h> +#include <linux/btrfs.h> +#include <linux/uio.h> +#include <linux/iversion.h> +#include <linux/fsverity.h> +#include "ctree.h" +#include "disk-io.h" +#include "transaction.h" +#include "btrfs_inode.h" +#include "print-tree.h" +#include "tree-log.h" +#include "locking.h" +#include "volumes.h" +#include "qgroup.h" +#include "compression.h" +#include "delalloc-space.h" +#include "reflink.h" +#include "subpage.h" + +/* simple helper to fault in pages and copy. This should go away + * and be replaced with calls into generic code. + */ +static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes, + struct page **prepared_pages, + struct iov_iter *i) +{ + size_t copied = 0; + size_t total_copied = 0; + int pg = 0; + int offset = offset_in_page(pos); + + while (write_bytes > 0) { + size_t count = min_t(size_t, + PAGE_SIZE - offset, write_bytes); + struct page *page = prepared_pages[pg]; + /* + * Copy data from userspace to the current page + */ + copied = copy_page_from_iter_atomic(page, offset, count, i); + + /* Flush processor's dcache for this page */ + flush_dcache_page(page); + + /* + * if we get a partial write, we can end up with + * partially up to date pages. These add + * a lot of complexity, so make sure they don't + * happen by forcing this copy to be retried. + * + * The rest of the btrfs_file_write code will fall + * back to page at a time copies after we return 0. + */ + if (unlikely(copied < count)) { + if (!PageUptodate(page)) { + iov_iter_revert(i, copied); + copied = 0; + } + if (!copied) + break; + } + + write_bytes -= copied; + total_copied += copied; + offset += copied; + if (offset == PAGE_SIZE) { + pg++; + offset = 0; + } + } + return total_copied; +} + +/* + * unlocks pages after btrfs_file_write is done with them + */ +static void btrfs_drop_pages(struct btrfs_fs_info *fs_info, + struct page **pages, size_t num_pages, + u64 pos, u64 copied) +{ + size_t i; + u64 block_start = round_down(pos, fs_info->sectorsize); + u64 block_len = round_up(pos + copied, fs_info->sectorsize) - block_start; + + ASSERT(block_len <= U32_MAX); + for (i = 0; i < num_pages; i++) { + /* page checked is some magic around finding pages that + * have been modified without going through btrfs_set_page_dirty + * clear it here. There should be no need to mark the pages + * accessed as prepare_pages should have marked them accessed + * in prepare_pages via find_or_create_page() + */ + btrfs_page_clamp_clear_checked(fs_info, pages[i], block_start, + block_len); + unlock_page(pages[i]); + put_page(pages[i]); + } +} + +/* + * After btrfs_copy_from_user(), update the following things for delalloc: + * - Mark newly dirtied pages as DELALLOC in the io tree. + * Used to advise which range is to be written back. + * - Mark modified pages as Uptodate/Dirty and not needing COW fixup + * - Update inode size for past EOF write + */ +int btrfs_dirty_pages(struct btrfs_inode *inode, struct page **pages, + size_t num_pages, loff_t pos, size_t write_bytes, + struct extent_state **cached, bool noreserve) +{ + struct btrfs_fs_info *fs_info = inode->root->fs_info; + int err = 0; + int i; + u64 num_bytes; + u64 start_pos; + u64 end_of_last_block; + u64 end_pos = pos + write_bytes; + loff_t isize = i_size_read(&inode->vfs_inode); + unsigned int extra_bits = 0; + + if (write_bytes == 0) + return 0; + + if (noreserve) + extra_bits |= EXTENT_NORESERVE; + + start_pos = round_down(pos, fs_info->sectorsize); + num_bytes = round_up(write_bytes + pos - start_pos, + fs_info->sectorsize); + ASSERT(num_bytes <= U32_MAX); + + end_of_last_block = start_pos + num_bytes - 1; + + /* + * The pages may have already been dirty, clear out old accounting so + * we can set things up properly + */ + clear_extent_bit(&inode->io_tree, start_pos, end_of_last_block, + EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, + cached); + + err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block, + extra_bits, cached); + if (err) + return err; + + for (i = 0; i < num_pages; i++) { + struct page *p = pages[i]; + + btrfs_page_clamp_set_uptodate(fs_info, p, start_pos, num_bytes); + btrfs_page_clamp_clear_checked(fs_info, p, start_pos, num_bytes); + btrfs_page_clamp_set_dirty(fs_info, p, start_pos, num_bytes); + } + + /* + * we've only changed i_size in ram, and we haven't updated + * the disk i_size. There is no need to log the inode + * at this time. + */ + if (end_pos > isize) + i_size_write(&inode->vfs_inode, end_pos); + return 0; +} + +/* + * this is very complex, but the basic idea is to drop all extents + * in the range start - end. hint_block is filled in with a block number + * that would be a good hint to the block allocator for this file. + * + * If an extent intersects the range but is not entirely inside the range + * it is either truncated or split. Anything entirely inside the range + * is deleted from the tree. + * + * Note: the VFS' inode number of bytes is not updated, it's up to the caller + * to deal with that. We set the field 'bytes_found' of the arguments structure + * with the number of allocated bytes found in the target range, so that the + * caller can update the inode's number of bytes in an atomic way when + * replacing extents in a range to avoid races with stat(2). + */ +int btrfs_drop_extents(struct btrfs_trans_handle *trans, + struct btrfs_root *root, struct btrfs_inode *inode, + struct btrfs_drop_extents_args *args) +{ + struct btrfs_fs_info *fs_info = root->fs_info; + struct extent_buffer *leaf; + struct btrfs_file_extent_item *fi; + struct btrfs_ref ref = { 0 }; + struct btrfs_key key; + struct btrfs_key new_key; + u64 ino = btrfs_ino(inode); + u64 search_start = args->start; + u64 disk_bytenr = 0; + u64 num_bytes = 0; + u64 extent_offset = 0; + u64 extent_end = 0; + u64 last_end = args->start; + int del_nr = 0; + int del_slot = 0; + int extent_type; + int recow; + int ret; + int modify_tree = -1; + int update_refs; + int found = 0; + struct btrfs_path *path = args->path; + + args->bytes_found = 0; + args->extent_inserted = false; + + /* Must always have a path if ->replace_extent is true */ + ASSERT(!(args->replace_extent && !args->path)); + + if (!path) { + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + } + + if (args->drop_cache) + btrfs_drop_extent_map_range(inode, args->start, args->end - 1, false); + + if (args->start >= inode->disk_i_size && !args->replace_extent) + modify_tree = 0; + + update_refs = (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID); + while (1) { + recow = 0; + ret = btrfs_lookup_file_extent(trans, root, path, ino, + search_start, modify_tree); + if (ret < 0) + break; + if (ret > 0 && path->slots[0] > 0 && search_start == args->start) { + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1); + if (key.objectid == ino && + key.type == BTRFS_EXTENT_DATA_KEY) + path->slots[0]--; + } + ret = 0; +next_slot: + leaf = path->nodes[0]; + if (path->slots[0] >= btrfs_header_nritems(leaf)) { + BUG_ON(del_nr > 0); + ret = btrfs_next_leaf(root, path); + if (ret < 0) + break; + if (ret > 0) { + ret = 0; + break; + } + leaf = path->nodes[0]; + recow = 1; + } + + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + + if (key.objectid > ino) + break; + if (WARN_ON_ONCE(key.objectid < ino) || + key.type < BTRFS_EXTENT_DATA_KEY) { + ASSERT(del_nr == 0); + path->slots[0]++; + goto next_slot; + } + if (key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= args->end) + break; + + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + extent_type = btrfs_file_extent_type(leaf, fi); + + if (extent_type == BTRFS_FILE_EXTENT_REG || + extent_type == BTRFS_FILE_EXTENT_PREALLOC) { + disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); + num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); + extent_offset = btrfs_file_extent_offset(leaf, fi); + extent_end = key.offset + + btrfs_file_extent_num_bytes(leaf, fi); + } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) { + extent_end = key.offset + + btrfs_file_extent_ram_bytes(leaf, fi); + } else { + /* can't happen */ + BUG(); + } + + /* + * Don't skip extent items representing 0 byte lengths. They + * used to be created (bug) if while punching holes we hit + * -ENOSPC condition. So if we find one here, just ensure we + * delete it, otherwise we would insert a new file extent item + * with the same key (offset) as that 0 bytes length file + * extent item in the call to setup_items_for_insert() later + * in this function. + */ + if (extent_end == key.offset && extent_end >= search_start) { + last_end = extent_end; + goto delete_extent_item; + } + + if (extent_end <= search_start) { + path->slots[0]++; + goto next_slot; + } + + found = 1; + search_start = max(key.offset, args->start); + if (recow || !modify_tree) { + modify_tree = -1; + btrfs_release_path(path); + continue; + } + + /* + * | - range to drop - | + * | -------- extent -------- | + */ + if (args->start > key.offset && args->end < extent_end) { + BUG_ON(del_nr > 0); + if (extent_type == BTRFS_FILE_EXTENT_INLINE) { + ret = -EOPNOTSUPP; + break; + } + + memcpy(&new_key, &key, sizeof(new_key)); + new_key.offset = args->start; + ret = btrfs_duplicate_item(trans, root, path, + &new_key); + if (ret == -EAGAIN) { + btrfs_release_path(path); + continue; + } + if (ret < 0) + break; + + leaf = path->nodes[0]; + fi = btrfs_item_ptr(leaf, path->slots[0] - 1, + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + args->start - key.offset); + + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + + extent_offset += args->start - key.offset; + btrfs_set_file_extent_offset(leaf, fi, extent_offset); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - args->start); + btrfs_mark_buffer_dirty(leaf); + + if (update_refs && disk_bytenr > 0) { + btrfs_init_generic_ref(&ref, + BTRFS_ADD_DELAYED_REF, + disk_bytenr, num_bytes, 0); + btrfs_init_data_ref(&ref, + root->root_key.objectid, + new_key.objectid, + args->start - extent_offset, + 0, false); + ret = btrfs_inc_extent_ref(trans, &ref); + if (ret) { + btrfs_abort_transaction(trans, ret); + break; + } + } + key.offset = args->start; + } + /* + * From here on out we will have actually dropped something, so + * last_end can be updated. + */ + last_end = extent_end; + + /* + * | ---- range to drop ----- | + * | -------- extent -------- | + */ + if (args->start <= key.offset && args->end < extent_end) { + if (extent_type == BTRFS_FILE_EXTENT_INLINE) { + ret = -EOPNOTSUPP; + break; + } + + memcpy(&new_key, &key, sizeof(new_key)); + new_key.offset = args->end; + btrfs_set_item_key_safe(fs_info, path, &new_key); + + extent_offset += args->end - key.offset; + btrfs_set_file_extent_offset(leaf, fi, extent_offset); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - args->end); + btrfs_mark_buffer_dirty(leaf); + if (update_refs && disk_bytenr > 0) + args->bytes_found += args->end - key.offset; + break; + } + + search_start = extent_end; + /* + * | ---- range to drop ----- | + * | -------- extent -------- | + */ + if (args->start > key.offset && args->end >= extent_end) { + BUG_ON(del_nr > 0); + if (extent_type == BTRFS_FILE_EXTENT_INLINE) { + ret = -EOPNOTSUPP; + break; + } + + btrfs_set_file_extent_num_bytes(leaf, fi, + args->start - key.offset); + btrfs_mark_buffer_dirty(leaf); + if (update_refs && disk_bytenr > 0) + args->bytes_found += extent_end - args->start; + if (args->end == extent_end) + break; + + path->slots[0]++; + goto next_slot; + } + + /* + * | ---- range to drop ----- | + * | ------ extent ------ | + */ + if (args->start <= key.offset && args->end >= extent_end) { +delete_extent_item: + if (del_nr == 0) { + del_slot = path->slots[0]; + del_nr = 1; + } else { + BUG_ON(del_slot + del_nr != path->slots[0]); + del_nr++; + } + + if (update_refs && + extent_type == BTRFS_FILE_EXTENT_INLINE) { + args->bytes_found += extent_end - key.offset; + extent_end = ALIGN(extent_end, + fs_info->sectorsize); + } else if (update_refs && disk_bytenr > 0) { + btrfs_init_generic_ref(&ref, + BTRFS_DROP_DELAYED_REF, + disk_bytenr, num_bytes, 0); + btrfs_init_data_ref(&ref, + root->root_key.objectid, + key.objectid, + key.offset - extent_offset, 0, + false); + ret = btrfs_free_extent(trans, &ref); + if (ret) { + btrfs_abort_transaction(trans, ret); + break; + } + args->bytes_found += extent_end - key.offset; + } + + if (args->end == extent_end) + break; + + if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) { + path->slots[0]++; + goto next_slot; + } + + ret = btrfs_del_items(trans, root, path, del_slot, + del_nr); + if (ret) { + btrfs_abort_transaction(trans, ret); + break; + } + + del_nr = 0; + del_slot = 0; + + btrfs_release_path(path); + continue; + } + + BUG(); + } + + if (!ret && del_nr > 0) { + /* + * Set path->slots[0] to first slot, so that after the delete + * if items are move off from our leaf to its immediate left or + * right neighbor leafs, we end up with a correct and adjusted + * path->slots[0] for our insertion (if args->replace_extent). + */ + path->slots[0] = del_slot; + ret = btrfs_del_items(trans, root, path, del_slot, del_nr); + if (ret) + btrfs_abort_transaction(trans, ret); + } + + leaf = path->nodes[0]; + /* + * If btrfs_del_items() was called, it might have deleted a leaf, in + * which case it unlocked our path, so check path->locks[0] matches a + * write lock. + */ + if (!ret && args->replace_extent && + path->locks[0] == BTRFS_WRITE_LOCK && + btrfs_leaf_free_space(leaf) >= + sizeof(struct btrfs_item) + args->extent_item_size) { + + key.objectid = ino; + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = args->start; + if (!del_nr && path->slots[0] < btrfs_header_nritems(leaf)) { + struct btrfs_key slot_key; + + btrfs_item_key_to_cpu(leaf, &slot_key, path->slots[0]); + if (btrfs_comp_cpu_keys(&key, &slot_key) > 0) + path->slots[0]++; + } + btrfs_setup_item_for_insert(root, path, &key, args->extent_item_size); + args->extent_inserted = true; + } + + if (!args->path) + btrfs_free_path(path); + else if (!args->extent_inserted) + btrfs_release_path(path); +out: + args->drop_end = found ? min(args->end, last_end) : args->end; + + return ret; +} + +static int extent_mergeable(struct extent_buffer *leaf, int slot, + u64 objectid, u64 bytenr, u64 orig_offset, + u64 *start, u64 *end) +{ + struct btrfs_file_extent_item *fi; + struct btrfs_key key; + u64 extent_end; + + if (slot < 0 || slot >= btrfs_header_nritems(leaf)) + return 0; + + btrfs_item_key_to_cpu(leaf, &key, slot); + if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY) + return 0; + + fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); + if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG || + btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr || + btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset || + btrfs_file_extent_compression(leaf, fi) || + btrfs_file_extent_encryption(leaf, fi) || + btrfs_file_extent_other_encoding(leaf, fi)) + return 0; + + extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi); + if ((*start && *start != key.offset) || (*end && *end != extent_end)) + return 0; + + *start = key.offset; + *end = extent_end; + return 1; +} + +/* + * Mark extent in the range start - end as written. + * + * This changes extent type from 'pre-allocated' to 'regular'. If only + * part of extent is marked as written, the extent will be split into + * two or three. + */ +int btrfs_mark_extent_written(struct btrfs_trans_handle *trans, + struct btrfs_inode *inode, u64 start, u64 end) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_root *root = inode->root; + struct extent_buffer *leaf; + struct btrfs_path *path; + struct btrfs_file_extent_item *fi; + struct btrfs_ref ref = { 0 }; + struct btrfs_key key; + struct btrfs_key new_key; + u64 bytenr; + u64 num_bytes; + u64 extent_end; + u64 orig_offset; + u64 other_start; + u64 other_end; + u64 split; + int del_nr = 0; + int del_slot = 0; + int recow; + int ret = 0; + u64 ino = btrfs_ino(inode); + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; +again: + recow = 0; + split = start; + key.objectid = ino; + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = split; + + ret = btrfs_search_slot(trans, root, &key, path, -1, 1); + if (ret < 0) + goto out; + if (ret > 0 && path->slots[0] > 0) + path->slots[0]--; + + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + if (key.objectid != ino || + key.type != BTRFS_EXTENT_DATA_KEY) { + ret = -EINVAL; + btrfs_abort_transaction(trans, ret); + goto out; + } + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_PREALLOC) { + ret = -EINVAL; + btrfs_abort_transaction(trans, ret); + goto out; + } + extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi); + if (key.offset > start || extent_end < end) { + ret = -EINVAL; + btrfs_abort_transaction(trans, ret); + goto out; + } + + bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); + num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); + orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi); + memcpy(&new_key, &key, sizeof(new_key)); + + if (start == key.offset && end < extent_end) { + other_start = 0; + other_end = start; + if (extent_mergeable(leaf, path->slots[0] - 1, + ino, bytenr, orig_offset, + &other_start, &other_end)) { + new_key.offset = end; + btrfs_set_item_key_safe(fs_info, path, &new_key); + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_generation(leaf, fi, + trans->transid); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - end); + btrfs_set_file_extent_offset(leaf, fi, + end - orig_offset); + fi = btrfs_item_ptr(leaf, path->slots[0] - 1, + struct btrfs_file_extent_item); + btrfs_set_file_extent_generation(leaf, fi, + trans->transid); + btrfs_set_file_extent_num_bytes(leaf, fi, + end - other_start); + btrfs_mark_buffer_dirty(leaf); + goto out; + } + } + + if (start > key.offset && end == extent_end) { + other_start = end; + other_end = 0; + if (extent_mergeable(leaf, path->slots[0] + 1, + ino, bytenr, orig_offset, + &other_start, &other_end)) { + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + start - key.offset); + btrfs_set_file_extent_generation(leaf, fi, + trans->transid); + path->slots[0]++; + new_key.offset = start; + btrfs_set_item_key_safe(fs_info, path, &new_key); + + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_generation(leaf, fi, + trans->transid); + btrfs_set_file_extent_num_bytes(leaf, fi, + other_end - start); + btrfs_set_file_extent_offset(leaf, fi, + start - orig_offset); + btrfs_mark_buffer_dirty(leaf); + goto out; + } + } + + while (start > key.offset || end < extent_end) { + if (key.offset == start) + split = end; + + new_key.offset = split; + ret = btrfs_duplicate_item(trans, root, path, &new_key); + if (ret == -EAGAIN) { + btrfs_release_path(path); + goto again; + } + if (ret < 0) { + btrfs_abort_transaction(trans, ret); + goto out; + } + + leaf = path->nodes[0]; + fi = btrfs_item_ptr(leaf, path->slots[0] - 1, + struct btrfs_file_extent_item); + btrfs_set_file_extent_generation(leaf, fi, trans->transid); + btrfs_set_file_extent_num_bytes(leaf, fi, + split - key.offset); + + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + + btrfs_set_file_extent_generation(leaf, fi, trans->transid); + btrfs_set_file_extent_offset(leaf, fi, split - orig_offset); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - split); + btrfs_mark_buffer_dirty(leaf); + + btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, bytenr, + num_bytes, 0); + btrfs_init_data_ref(&ref, root->root_key.objectid, ino, + orig_offset, 0, false); + ret = btrfs_inc_extent_ref(trans, &ref); + if (ret) { + btrfs_abort_transaction(trans, ret); + goto out; + } + + if (split == start) { + key.offset = start; + } else { + if (start != key.offset) { + ret = -EINVAL; + btrfs_abort_transaction(trans, ret); + goto out; + } + path->slots[0]--; + extent_end = end; + } + recow = 1; + } + + other_start = end; + other_end = 0; + btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr, + num_bytes, 0); + btrfs_init_data_ref(&ref, root->root_key.objectid, ino, orig_offset, + 0, false); + if (extent_mergeable(leaf, path->slots[0] + 1, + ino, bytenr, orig_offset, + &other_start, &other_end)) { + if (recow) { + btrfs_release_path(path); + goto again; + } + extent_end = other_end; + del_slot = path->slots[0] + 1; + del_nr++; + ret = btrfs_free_extent(trans, &ref); + if (ret) { + btrfs_abort_transaction(trans, ret); + goto out; + } + } + other_start = 0; + other_end = start; + if (extent_mergeable(leaf, path->slots[0] - 1, + ino, bytenr, orig_offset, + &other_start, &other_end)) { + if (recow) { + btrfs_release_path(path); + goto again; + } + key.offset = other_start; + del_slot = path->slots[0]; + del_nr++; + ret = btrfs_free_extent(trans, &ref); + if (ret) { + btrfs_abort_transaction(trans, ret); + goto out; + } + } + if (del_nr == 0) { + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_type(leaf, fi, + BTRFS_FILE_EXTENT_REG); + btrfs_set_file_extent_generation(leaf, fi, trans->transid); + btrfs_mark_buffer_dirty(leaf); + } else { + fi = btrfs_item_ptr(leaf, del_slot - 1, + struct btrfs_file_extent_item); + btrfs_set_file_extent_type(leaf, fi, + BTRFS_FILE_EXTENT_REG); + btrfs_set_file_extent_generation(leaf, fi, trans->transid); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - key.offset); + btrfs_mark_buffer_dirty(leaf); + + ret = btrfs_del_items(trans, root, path, del_slot, del_nr); + if (ret < 0) { + btrfs_abort_transaction(trans, ret); + goto out; + } + } +out: + btrfs_free_path(path); + return ret; +} + +/* + * on error we return an unlocked page and the error value + * on success we return a locked page and 0 + */ +static int prepare_uptodate_page(struct inode *inode, + struct page *page, u64 pos, + bool force_uptodate) +{ + struct folio *folio = page_folio(page); + int ret = 0; + + if (((pos & (PAGE_SIZE - 1)) || force_uptodate) && + !PageUptodate(page)) { + ret = btrfs_read_folio(NULL, folio); + if (ret) + return ret; + lock_page(page); + if (!PageUptodate(page)) { + unlock_page(page); + return -EIO; + } + + /* + * Since btrfs_read_folio() will unlock the folio before it + * returns, there is a window where btrfs_release_folio() can be + * called to release the page. Here we check both inode + * mapping and PagePrivate() to make sure the page was not + * released. + * + * The private flag check is essential for subpage as we need + * to store extra bitmap using page->private. + */ + if (page->mapping != inode->i_mapping || !PagePrivate(page)) { + unlock_page(page); + return -EAGAIN; + } + } + return 0; +} + +static unsigned int get_prepare_fgp_flags(bool nowait) +{ + unsigned int fgp_flags = FGP_LOCK | FGP_ACCESSED | FGP_CREAT; + + if (nowait) + fgp_flags |= FGP_NOWAIT; + + return fgp_flags; +} + +static gfp_t get_prepare_gfp_flags(struct inode *inode, bool nowait) +{ + gfp_t gfp; + + gfp = btrfs_alloc_write_mask(inode->i_mapping); + if (nowait) { + gfp &= ~__GFP_DIRECT_RECLAIM; + gfp |= GFP_NOWAIT; + } + + return gfp; +} + +/* + * this just gets pages into the page cache and locks them down. + */ +static noinline int prepare_pages(struct inode *inode, struct page **pages, + size_t num_pages, loff_t pos, + size_t write_bytes, bool force_uptodate, + bool nowait) +{ + int i; + unsigned long index = pos >> PAGE_SHIFT; + gfp_t mask = get_prepare_gfp_flags(inode, nowait); + unsigned int fgp_flags = get_prepare_fgp_flags(nowait); + int err = 0; + int faili; + + for (i = 0; i < num_pages; i++) { +again: + pages[i] = pagecache_get_page(inode->i_mapping, index + i, + fgp_flags, mask | __GFP_WRITE); + if (!pages[i]) { + faili = i - 1; + if (nowait) + err = -EAGAIN; + else + err = -ENOMEM; + goto fail; + } + + err = set_page_extent_mapped(pages[i]); + if (err < 0) { + faili = i; + goto fail; + } + + if (i == 0) + err = prepare_uptodate_page(inode, pages[i], pos, + force_uptodate); + if (!err && i == num_pages - 1) + err = prepare_uptodate_page(inode, pages[i], + pos + write_bytes, false); + if (err) { + put_page(pages[i]); + if (!nowait && err == -EAGAIN) { + err = 0; + goto again; + } + faili = i - 1; + goto fail; + } + wait_on_page_writeback(pages[i]); + } + + return 0; +fail: + while (faili >= 0) { + unlock_page(pages[faili]); + put_page(pages[faili]); + faili--; + } + return err; + +} + +/* + * This function locks the extent and properly waits for data=ordered extents + * to finish before allowing the pages to be modified if need. + * + * The return value: + * 1 - the extent is locked + * 0 - the extent is not locked, and everything is OK + * -EAGAIN - need re-prepare the pages + * the other < 0 number - Something wrong happens + */ +static noinline int +lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages, + size_t num_pages, loff_t pos, + size_t write_bytes, + u64 *lockstart, u64 *lockend, bool nowait, + struct extent_state **cached_state) +{ + struct btrfs_fs_info *fs_info = inode->root->fs_info; + u64 start_pos; + u64 last_pos; + int i; + int ret = 0; + + start_pos = round_down(pos, fs_info->sectorsize); + last_pos = round_up(pos + write_bytes, fs_info->sectorsize) - 1; + + if (start_pos < inode->vfs_inode.i_size) { + struct btrfs_ordered_extent *ordered; + + if (nowait) { + if (!try_lock_extent(&inode->io_tree, start_pos, last_pos)) { + for (i = 0; i < num_pages; i++) { + unlock_page(pages[i]); + put_page(pages[i]); + pages[i] = NULL; + } + + return -EAGAIN; + } + } else { + lock_extent(&inode->io_tree, start_pos, last_pos, cached_state); + } + + ordered = btrfs_lookup_ordered_range(inode, start_pos, + last_pos - start_pos + 1); + if (ordered && + ordered->file_offset + ordered->num_bytes > start_pos && + ordered->file_offset <= last_pos) { + unlock_extent(&inode->io_tree, start_pos, last_pos, + cached_state); + for (i = 0; i < num_pages; i++) { + unlock_page(pages[i]); + put_page(pages[i]); + } + btrfs_start_ordered_extent(ordered, 1); + btrfs_put_ordered_extent(ordered); + return -EAGAIN; + } + if (ordered) + btrfs_put_ordered_extent(ordered); + + *lockstart = start_pos; + *lockend = last_pos; + ret = 1; + } + + /* + * We should be called after prepare_pages() which should have locked + * all pages in the range. + */ + for (i = 0; i < num_pages; i++) + WARN_ON(!PageLocked(pages[i])); + + return ret; +} + +/* + * Check if we can do nocow write into the range [@pos, @pos + @write_bytes) + * + * @pos: File offset. + * @write_bytes: The length to write, will be updated to the nocow writeable + * range. + * + * This function will flush ordered extents in the range to ensure proper + * nocow checks. + * + * Return: + * > 0 If we can nocow, and updates @write_bytes. + * 0 If we can't do a nocow write. + * -EAGAIN If we can't do a nocow write because snapshoting of the inode's + * root is in progress. + * < 0 If an error happened. + * + * NOTE: Callers need to call btrfs_check_nocow_unlock() if we return > 0. + */ +int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos, + size_t *write_bytes, bool nowait) +{ + struct btrfs_fs_info *fs_info = inode->root->fs_info; + struct btrfs_root *root = inode->root; + u64 lockstart, lockend; + u64 num_bytes; + int ret; + + if (!(inode->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC))) + return 0; + + if (!btrfs_drew_try_write_lock(&root->snapshot_lock)) + return -EAGAIN; + + lockstart = round_down(pos, fs_info->sectorsize); + lockend = round_up(pos + *write_bytes, + fs_info->sectorsize) - 1; + num_bytes = lockend - lockstart + 1; + + if (nowait) { + if (!btrfs_try_lock_ordered_range(inode, lockstart, lockend)) { + btrfs_drew_write_unlock(&root->snapshot_lock); + return -EAGAIN; + } + } else { + btrfs_lock_and_flush_ordered_range(inode, lockstart, lockend, NULL); + } + ret = can_nocow_extent(&inode->vfs_inode, lockstart, &num_bytes, + NULL, NULL, NULL, nowait, false); + if (ret <= 0) + btrfs_drew_write_unlock(&root->snapshot_lock); + else + *write_bytes = min_t(size_t, *write_bytes , + num_bytes - pos + lockstart); + unlock_extent(&inode->io_tree, lockstart, lockend, NULL); + + return ret; +} + +void btrfs_check_nocow_unlock(struct btrfs_inode *inode) +{ + btrfs_drew_write_unlock(&inode->root->snapshot_lock); +} + +static void update_time_for_write(struct inode *inode) +{ + struct timespec64 now; + + if (IS_NOCMTIME(inode)) + return; + + now = current_time(inode); + if (!timespec64_equal(&inode->i_mtime, &now)) + inode->i_mtime = now; + + if (!timespec64_equal(&inode->i_ctime, &now)) + inode->i_ctime = now; + + if (IS_I_VERSION(inode)) + inode_inc_iversion(inode); +} + +static int btrfs_write_check(struct kiocb *iocb, struct iov_iter *from, + size_t count) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file_inode(file); + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + loff_t pos = iocb->ki_pos; + int ret; + loff_t oldsize; + loff_t start_pos; + + /* + * Quickly bail out on NOWAIT writes if we don't have the nodatacow or + * prealloc flags, as without those flags we always have to COW. We will + * later check if we can really COW into the target range (using + * can_nocow_extent() at btrfs_get_blocks_direct_write()). + */ + if ((iocb->ki_flags & IOCB_NOWAIT) && + !(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | BTRFS_INODE_PREALLOC))) + return -EAGAIN; + + current->backing_dev_info = inode_to_bdi(inode); + ret = file_remove_privs(file); + if (ret) + return ret; + + /* + * We reserve space for updating the inode when we reserve space for the + * extent we are going to write, so we will enospc out there. We don't + * need to start yet another transaction to update the inode as we will + * update the inode when we finish writing whatever data we write. + */ + update_time_for_write(inode); + + start_pos = round_down(pos, fs_info->sectorsize); + oldsize = i_size_read(inode); + if (start_pos > oldsize) { + /* Expand hole size to cover write data, preventing empty gap */ + loff_t end_pos = round_up(pos + count, fs_info->sectorsize); + + ret = btrfs_cont_expand(BTRFS_I(inode), oldsize, end_pos); + if (ret) { + current->backing_dev_info = NULL; + return ret; + } + } + + return 0; +} + +static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb, + struct iov_iter *i) +{ + struct file *file = iocb->ki_filp; + loff_t pos; + struct inode *inode = file_inode(file); + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + struct page **pages = NULL; + struct extent_changeset *data_reserved = NULL; + u64 release_bytes = 0; + u64 lockstart; + u64 lockend; + size_t num_written = 0; + int nrptrs; + ssize_t ret; + bool only_release_metadata = false; + bool force_page_uptodate = false; + loff_t old_isize = i_size_read(inode); + unsigned int ilock_flags = 0; + const bool nowait = (iocb->ki_flags & IOCB_NOWAIT); + unsigned int bdp_flags = (nowait ? BDP_ASYNC : 0); + + if (nowait) + ilock_flags |= BTRFS_ILOCK_TRY; + + ret = btrfs_inode_lock(inode, ilock_flags); + if (ret < 0) + return ret; + + ret = generic_write_checks(iocb, i); + if (ret <= 0) + goto out; + + ret = btrfs_write_check(iocb, i, ret); + if (ret < 0) + goto out; + + pos = iocb->ki_pos; + nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_SIZE), + PAGE_SIZE / (sizeof(struct page *))); + nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied); + nrptrs = max(nrptrs, 8); + pages = kmalloc_array(nrptrs, sizeof(struct page *), GFP_KERNEL); + if (!pages) { + ret = -ENOMEM; + goto out; + } + + while (iov_iter_count(i) > 0) { + struct extent_state *cached_state = NULL; + size_t offset = offset_in_page(pos); + size_t sector_offset; + size_t write_bytes = min(iov_iter_count(i), + nrptrs * (size_t)PAGE_SIZE - + offset); + size_t num_pages; + size_t reserve_bytes; + size_t dirty_pages; + size_t copied; + size_t dirty_sectors; + size_t num_sectors; + int extents_locked; + + /* + * Fault pages before locking them in prepare_pages + * to avoid recursive lock + */ + if (unlikely(fault_in_iov_iter_readable(i, write_bytes))) { + ret = -EFAULT; + break; + } + + only_release_metadata = false; + sector_offset = pos & (fs_info->sectorsize - 1); + + extent_changeset_release(data_reserved); + ret = btrfs_check_data_free_space(BTRFS_I(inode), + &data_reserved, pos, + write_bytes, nowait); + if (ret < 0) { + int can_nocow; + + if (nowait && (ret == -ENOSPC || ret == -EAGAIN)) { + ret = -EAGAIN; + break; + } + + /* + * If we don't have to COW at the offset, reserve + * metadata only. write_bytes may get smaller than + * requested here. + */ + can_nocow = btrfs_check_nocow_lock(BTRFS_I(inode), pos, + &write_bytes, nowait); + if (can_nocow < 0) + ret = can_nocow; + if (can_nocow > 0) + ret = 0; + if (ret) + break; + only_release_metadata = true; + } + + num_pages = DIV_ROUND_UP(write_bytes + offset, PAGE_SIZE); + WARN_ON(num_pages > nrptrs); + reserve_bytes = round_up(write_bytes + sector_offset, + fs_info->sectorsize); + WARN_ON(reserve_bytes == 0); + ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), + reserve_bytes, + reserve_bytes, nowait); + if (ret) { + if (!only_release_metadata) + btrfs_free_reserved_data_space(BTRFS_I(inode), + data_reserved, pos, + write_bytes); + else + btrfs_check_nocow_unlock(BTRFS_I(inode)); + + if (nowait && ret == -ENOSPC) + ret = -EAGAIN; + break; + } + + release_bytes = reserve_bytes; +again: + ret = balance_dirty_pages_ratelimited_flags(inode->i_mapping, bdp_flags); + if (ret) { + btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes); + break; + } + + /* + * This is going to setup the pages array with the number of + * pages we want, so we don't really need to worry about the + * contents of pages from loop to loop + */ + ret = prepare_pages(inode, pages, num_pages, + pos, write_bytes, force_page_uptodate, false); + if (ret) { + btrfs_delalloc_release_extents(BTRFS_I(inode), + reserve_bytes); + break; + } + + extents_locked = lock_and_cleanup_extent_if_need( + BTRFS_I(inode), pages, + num_pages, pos, write_bytes, &lockstart, + &lockend, nowait, &cached_state); + if (extents_locked < 0) { + if (!nowait && extents_locked == -EAGAIN) + goto again; + + btrfs_delalloc_release_extents(BTRFS_I(inode), + reserve_bytes); + ret = extents_locked; + break; + } + + copied = btrfs_copy_from_user(pos, write_bytes, pages, i); + + num_sectors = BTRFS_BYTES_TO_BLKS(fs_info, reserve_bytes); + dirty_sectors = round_up(copied + sector_offset, + fs_info->sectorsize); + dirty_sectors = BTRFS_BYTES_TO_BLKS(fs_info, dirty_sectors); + + /* + * if we have trouble faulting in the pages, fall + * back to one page at a time + */ + if (copied < write_bytes) + nrptrs = 1; + + if (copied == 0) { + force_page_uptodate = true; + dirty_sectors = 0; + dirty_pages = 0; + } else { + force_page_uptodate = false; + dirty_pages = DIV_ROUND_UP(copied + offset, + PAGE_SIZE); + } + + if (num_sectors > dirty_sectors) { + /* release everything except the sectors we dirtied */ + release_bytes -= dirty_sectors << fs_info->sectorsize_bits; + if (only_release_metadata) { + btrfs_delalloc_release_metadata(BTRFS_I(inode), + release_bytes, true); + } else { + u64 __pos; + + __pos = round_down(pos, + fs_info->sectorsize) + + (dirty_pages << PAGE_SHIFT); + btrfs_delalloc_release_space(BTRFS_I(inode), + data_reserved, __pos, + release_bytes, true); + } + } + + release_bytes = round_up(copied + sector_offset, + fs_info->sectorsize); + + ret = btrfs_dirty_pages(BTRFS_I(inode), pages, + dirty_pages, pos, copied, + &cached_state, only_release_metadata); + + /* + * If we have not locked the extent range, because the range's + * start offset is >= i_size, we might still have a non-NULL + * cached extent state, acquired while marking the extent range + * as delalloc through btrfs_dirty_pages(). Therefore free any + * possible cached extent state to avoid a memory leak. + */ + if (extents_locked) + unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, + lockend, &cached_state); + else + free_extent_state(cached_state); + + btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes); + if (ret) { + btrfs_drop_pages(fs_info, pages, num_pages, pos, copied); + break; + } + + release_bytes = 0; + if (only_release_metadata) + btrfs_check_nocow_unlock(BTRFS_I(inode)); + + btrfs_drop_pages(fs_info, pages, num_pages, pos, copied); + + cond_resched(); + + pos += copied; + num_written += copied; + } + + kfree(pages); + + if (release_bytes) { + if (only_release_metadata) { + btrfs_check_nocow_unlock(BTRFS_I(inode)); + btrfs_delalloc_release_metadata(BTRFS_I(inode), + release_bytes, true); + } else { + btrfs_delalloc_release_space(BTRFS_I(inode), + data_reserved, + round_down(pos, fs_info->sectorsize), + release_bytes, true); + } + } + + extent_changeset_free(data_reserved); + if (num_written > 0) { + pagecache_isize_extended(inode, old_isize, iocb->ki_pos); + iocb->ki_pos += num_written; + } +out: + btrfs_inode_unlock(inode, ilock_flags); + return num_written ? num_written : ret; +} + +static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info, + const struct iov_iter *iter, loff_t offset) +{ + const u32 blocksize_mask = fs_info->sectorsize - 1; + + if (offset & blocksize_mask) + return -EINVAL; + + if (iov_iter_alignment(iter) & blocksize_mask) + return -EINVAL; + + return 0; +} + +static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file_inode(file); + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + loff_t pos; + ssize_t written = 0; + ssize_t written_buffered; + size_t prev_left = 0; + loff_t endbyte; + ssize_t err; + unsigned int ilock_flags = 0; + struct iomap_dio *dio; + + if (iocb->ki_flags & IOCB_NOWAIT) + ilock_flags |= BTRFS_ILOCK_TRY; + + /* + * If the write DIO is within EOF, use a shared lock and also only if + * security bits will likely not be dropped by file_remove_privs() called + * from btrfs_write_check(). Either will need to be rechecked after the + * lock was acquired. + */ + if (iocb->ki_pos + iov_iter_count(from) <= i_size_read(inode) && IS_NOSEC(inode)) + ilock_flags |= BTRFS_ILOCK_SHARED; + +relock: + err = btrfs_inode_lock(inode, ilock_flags); + if (err < 0) + return err; + + /* Shared lock cannot be used with security bits set. */ + if ((ilock_flags & BTRFS_ILOCK_SHARED) && !IS_NOSEC(inode)) { + btrfs_inode_unlock(inode, ilock_flags); + ilock_flags &= ~BTRFS_ILOCK_SHARED; + goto relock; + } + + err = generic_write_checks(iocb, from); + if (err <= 0) { + btrfs_inode_unlock(inode, ilock_flags); + return err; + } + + err = btrfs_write_check(iocb, from, err); + if (err < 0) { + btrfs_inode_unlock(inode, ilock_flags); + goto out; + } + + pos = iocb->ki_pos; + /* + * Re-check since file size may have changed just before taking the + * lock or pos may have changed because of O_APPEND in generic_write_check() + */ + if ((ilock_flags & BTRFS_ILOCK_SHARED) && + pos + iov_iter_count(from) > i_size_read(inode)) { + btrfs_inode_unlock(inode, ilock_flags); + ilock_flags &= ~BTRFS_ILOCK_SHARED; + goto relock; + } + + if (check_direct_IO(fs_info, from, pos)) { + btrfs_inode_unlock(inode, ilock_flags); + goto buffered; + } + + /* + * The iov_iter can be mapped to the same file range we are writing to. + * If that's the case, then we will deadlock in the iomap code, because + * it first calls our callback btrfs_dio_iomap_begin(), which will create + * an ordered extent, and after that it will fault in the pages that the + * iov_iter refers to. During the fault in we end up in the readahead + * pages code (starting at btrfs_readahead()), which will lock the range, + * find that ordered extent and then wait for it to complete (at + * btrfs_lock_and_flush_ordered_range()), resulting in a deadlock since + * obviously the ordered extent can never complete as we didn't submit + * yet the respective bio(s). This always happens when the buffer is + * memory mapped to the same file range, since the iomap DIO code always + * invalidates pages in the target file range (after starting and waiting + * for any writeback). + * + * So here we disable page faults in the iov_iter and then retry if we + * got -EFAULT, faulting in the pages before the retry. + */ + from->nofault = true; + dio = btrfs_dio_write(iocb, from, written); + from->nofault = false; + + /* + * iomap_dio_complete() will call btrfs_sync_file() if we have a dsync + * iocb, and that needs to lock the inode. So unlock it before calling + * iomap_dio_complete() to avoid a deadlock. + */ + btrfs_inode_unlock(inode, ilock_flags); + + if (IS_ERR_OR_NULL(dio)) + err = PTR_ERR_OR_ZERO(dio); + else + err = iomap_dio_complete(dio); + + /* No increment (+=) because iomap returns a cumulative value. */ + if (err > 0) + written = err; + + if (iov_iter_count(from) > 0 && (err == -EFAULT || err > 0)) { + const size_t left = iov_iter_count(from); + /* + * We have more data left to write. Try to fault in as many as + * possible of the remainder pages and retry. We do this without + * releasing and locking again the inode, to prevent races with + * truncate. + * + * Also, in case the iov refers to pages in the file range of the + * file we want to write to (due to a mmap), we could enter an + * infinite loop if we retry after faulting the pages in, since + * iomap will invalidate any pages in the range early on, before + * it tries to fault in the pages of the iov. So we keep track of + * how much was left of iov in the previous EFAULT and fallback + * to buffered IO in case we haven't made any progress. + */ + if (left == prev_left) { + err = -ENOTBLK; + } else { + fault_in_iov_iter_readable(from, left); + prev_left = left; + goto relock; + } + } + + /* + * If 'err' is -ENOTBLK or we have not written all data, then it means + * we must fallback to buffered IO. + */ + if ((err < 0 && err != -ENOTBLK) || !iov_iter_count(from)) + goto out; + +buffered: + /* + * If we are in a NOWAIT context, then return -EAGAIN to signal the caller + * it must retry the operation in a context where blocking is acceptable, + * since we currently don't have NOWAIT semantics support for buffered IO + * and may block there for many reasons (reserving space for example). + */ + if (iocb->ki_flags & IOCB_NOWAIT) { + err = -EAGAIN; + goto out; + } + + pos = iocb->ki_pos; + written_buffered = btrfs_buffered_write(iocb, from); + if (written_buffered < 0) { + err = written_buffered; + goto out; + } + /* + * Ensure all data is persisted. We want the next direct IO read to be + * able to read what was just written. + */ + endbyte = pos + written_buffered - 1; + err = btrfs_fdatawrite_range(inode, pos, endbyte); + if (err) + goto out; + err = filemap_fdatawait_range(inode->i_mapping, pos, endbyte); + if (err) + goto out; + written += written_buffered; + iocb->ki_pos = pos + written_buffered; + invalidate_mapping_pages(file->f_mapping, pos >> PAGE_SHIFT, + endbyte >> PAGE_SHIFT); +out: + return err < 0 ? err : written; +} + +static ssize_t btrfs_encoded_write(struct kiocb *iocb, struct iov_iter *from, + const struct btrfs_ioctl_encoded_io_args *encoded) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file_inode(file); + loff_t count; + ssize_t ret; + + btrfs_inode_lock(inode, 0); + count = encoded->len; + ret = generic_write_checks_count(iocb, &count); + if (ret == 0 && count != encoded->len) { + /* + * The write got truncated by generic_write_checks_count(). We + * can't do a partial encoded write. + */ + ret = -EFBIG; + } + if (ret || encoded->len == 0) + goto out; + + ret = btrfs_write_check(iocb, from, encoded->len); + if (ret < 0) + goto out; + + ret = btrfs_do_encoded_write(iocb, from, encoded); +out: + btrfs_inode_unlock(inode, 0); + return ret; +} + +ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from, + const struct btrfs_ioctl_encoded_io_args *encoded) +{ + struct file *file = iocb->ki_filp; + struct btrfs_inode *inode = BTRFS_I(file_inode(file)); + ssize_t num_written, num_sync; + const bool sync = iocb_is_dsync(iocb); + + /* + * If the fs flips readonly due to some impossible error, although we + * have opened a file as writable, we have to stop this write operation + * to ensure consistency. + */ + if (BTRFS_FS_ERROR(inode->root->fs_info)) + return -EROFS; + + if (encoded && (iocb->ki_flags & IOCB_NOWAIT)) + return -EOPNOTSUPP; + + if (sync) + atomic_inc(&inode->sync_writers); + + if (encoded) { + num_written = btrfs_encoded_write(iocb, from, encoded); + num_sync = encoded->len; + } else if (iocb->ki_flags & IOCB_DIRECT) { + num_written = btrfs_direct_write(iocb, from); + num_sync = num_written; + } else { + num_written = btrfs_buffered_write(iocb, from); + num_sync = num_written; + } + + btrfs_set_inode_last_sub_trans(inode); + + if (num_sync > 0) { + num_sync = generic_write_sync(iocb, num_sync); + if (num_sync < 0) + num_written = num_sync; + } + + if (sync) + atomic_dec(&inode->sync_writers); + + current->backing_dev_info = NULL; + return num_written; +} + +static ssize_t btrfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + return btrfs_do_write_iter(iocb, from, NULL); +} + +int btrfs_release_file(struct inode *inode, struct file *filp) +{ + struct btrfs_file_private *private = filp->private_data; + + if (private && private->filldir_buf) + kfree(private->filldir_buf); + kfree(private); + filp->private_data = NULL; + + /* + * Set by setattr when we are about to truncate a file from a non-zero + * size to a zero size. This tries to flush down new bytes that may + * have been written if the application were using truncate to replace + * a file in place. + */ + if (test_and_clear_bit(BTRFS_INODE_FLUSH_ON_CLOSE, + &BTRFS_I(inode)->runtime_flags)) + filemap_flush(inode->i_mapping); + return 0; +} + +static int start_ordered_ops(struct inode *inode, loff_t start, loff_t end) +{ + int ret; + struct blk_plug plug; + + /* + * This is only called in fsync, which would do synchronous writes, so + * a plug can merge adjacent IOs as much as possible. Esp. in case of + * multiple disks using raid profile, a large IO can be split to + * several segments of stripe length (currently 64K). + */ + blk_start_plug(&plug); + atomic_inc(&BTRFS_I(inode)->sync_writers); + ret = btrfs_fdatawrite_range(inode, start, end); + atomic_dec(&BTRFS_I(inode)->sync_writers); + blk_finish_plug(&plug); + + return ret; +} + +static inline bool skip_inode_logging(const struct btrfs_log_ctx *ctx) +{ + struct btrfs_inode *inode = BTRFS_I(ctx->inode); + struct btrfs_fs_info *fs_info = inode->root->fs_info; + + if (btrfs_inode_in_log(inode, fs_info->generation) && + list_empty(&ctx->ordered_extents)) + return true; + + /* + * If we are doing a fast fsync we can not bail out if the inode's + * last_trans is <= then the last committed transaction, because we only + * update the last_trans of the inode during ordered extent completion, + * and for a fast fsync we don't wait for that, we only wait for the + * writeback to complete. + */ + if (inode->last_trans <= fs_info->last_trans_committed && + (test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags) || + list_empty(&ctx->ordered_extents))) + return true; + + return false; +} + +/* + * fsync call for both files and directories. This logs the inode into + * the tree log instead of forcing full commits whenever possible. + * + * It needs to call filemap_fdatawait so that all ordered extent updates are + * in the metadata btree are up to date for copying to the log. + * + * It drops the inode mutex before doing the tree log commit. This is an + * important optimization for directories because holding the mutex prevents + * new operations on the dir while we write to disk. + */ +int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) +{ + struct dentry *dentry = file_dentry(file); + struct inode *inode = d_inode(dentry); + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + struct btrfs_root *root = BTRFS_I(inode)->root; + struct btrfs_trans_handle *trans; + struct btrfs_log_ctx ctx; + int ret = 0, err; + u64 len; + bool full_sync; + + trace_btrfs_sync_file(file, datasync); + + btrfs_init_log_ctx(&ctx, inode); + + /* + * Always set the range to a full range, otherwise we can get into + * several problems, from missing file extent items to represent holes + * when not using the NO_HOLES feature, to log tree corruption due to + * races between hole detection during logging and completion of ordered + * extents outside the range, to missing checksums due to ordered extents + * for which we flushed only a subset of their pages. + */ + start = 0; + end = LLONG_MAX; + len = (u64)LLONG_MAX + 1; + + /* + * We write the dirty pages in the range and wait until they complete + * out of the ->i_mutex. If so, we can flush the dirty pages by + * multi-task, and make the performance up. See + * btrfs_wait_ordered_range for an explanation of the ASYNC check. + */ + ret = start_ordered_ops(inode, start, end); + if (ret) + goto out; + + btrfs_inode_lock(inode, BTRFS_ILOCK_MMAP); + + atomic_inc(&root->log_batch); + + /* + * Before we acquired the inode's lock and the mmap lock, someone may + * have dirtied more pages in the target range. We need to make sure + * that writeback for any such pages does not start while we are logging + * the inode, because if it does, any of the following might happen when + * we are not doing a full inode sync: + * + * 1) We log an extent after its writeback finishes but before its + * checksums are added to the csum tree, leading to -EIO errors + * when attempting to read the extent after a log replay. + * + * 2) We can end up logging an extent before its writeback finishes. + * Therefore after the log replay we will have a file extent item + * pointing to an unwritten extent (and no data checksums as well). + * + * So trigger writeback for any eventual new dirty pages and then we + * wait for all ordered extents to complete below. + */ + ret = start_ordered_ops(inode, start, end); + if (ret) { + btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP); + goto out; + } + + /* + * Always check for the full sync flag while holding the inode's lock, + * to avoid races with other tasks. The flag must be either set all the + * time during logging or always off all the time while logging. + * We check the flag here after starting delalloc above, because when + * running delalloc the full sync flag may be set if we need to drop + * extra extent map ranges due to temporary memory allocation failures. + */ + full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, + &BTRFS_I(inode)->runtime_flags); + + /* + * We have to do this here to avoid the priority inversion of waiting on + * IO of a lower priority task while holding a transaction open. + * + * For a full fsync we wait for the ordered extents to complete while + * for a fast fsync we wait just for writeback to complete, and then + * attach the ordered extents to the transaction so that a transaction + * commit waits for their completion, to avoid data loss if we fsync, + * the current transaction commits before the ordered extents complete + * and a power failure happens right after that. + * + * For zoned filesystem, if a write IO uses a ZONE_APPEND command, the + * logical address recorded in the ordered extent may change. We need + * to wait for the IO to stabilize the logical address. + */ + if (full_sync || btrfs_is_zoned(fs_info)) { + ret = btrfs_wait_ordered_range(inode, start, len); + } else { + /* + * Get our ordered extents as soon as possible to avoid doing + * checksum lookups in the csum tree, and use instead the + * checksums attached to the ordered extents. + */ + btrfs_get_ordered_extents_for_logging(BTRFS_I(inode), + &ctx.ordered_extents); + ret = filemap_fdatawait_range(inode->i_mapping, start, end); + } + + if (ret) + goto out_release_extents; + + atomic_inc(&root->log_batch); + + smp_mb(); + if (skip_inode_logging(&ctx)) { + /* + * We've had everything committed since the last time we were + * modified so clear this flag in case it was set for whatever + * reason, it's no longer relevant. + */ + clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC, + &BTRFS_I(inode)->runtime_flags); + /* + * An ordered extent might have started before and completed + * already with io errors, in which case the inode was not + * updated and we end up here. So check the inode's mapping + * for any errors that might have happened since we last + * checked called fsync. + */ + ret = filemap_check_wb_err(inode->i_mapping, file->f_wb_err); + goto out_release_extents; + } + + /* + * We use start here because we will need to wait on the IO to complete + * in btrfs_sync_log, which could require joining a transaction (for + * example checking cross references in the nocow path). If we use join + * here we could get into a situation where we're waiting on IO to + * happen that is blocked on a transaction trying to commit. With start + * we inc the extwriter counter, so we wait for all extwriters to exit + * before we start blocking joiners. This comment is to keep somebody + * from thinking they are super smart and changing this to + * btrfs_join_transaction *cough*Josef*cough*. + */ + trans = btrfs_start_transaction(root, 0); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + goto out_release_extents; + } + trans->in_fsync = true; + + ret = btrfs_log_dentry_safe(trans, dentry, &ctx); + btrfs_release_log_ctx_extents(&ctx); + if (ret < 0) { + /* Fallthrough and commit/free transaction. */ + ret = BTRFS_LOG_FORCE_COMMIT; + } + + /* we've logged all the items and now have a consistent + * version of the file in the log. It is possible that + * someone will come in and modify the file, but that's + * fine because the log is consistent on disk, and we + * have references to all of the file's extents + * + * It is possible that someone will come in and log the + * file again, but that will end up using the synchronization + * inside btrfs_sync_log to keep things safe. + */ + btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP); + + if (ret == BTRFS_NO_LOG_SYNC) { + ret = btrfs_end_transaction(trans); + goto out; + } + + /* We successfully logged the inode, attempt to sync the log. */ + if (!ret) { + ret = btrfs_sync_log(trans, root, &ctx); + if (!ret) { + ret = btrfs_end_transaction(trans); + goto out; + } + } + + /* + * At this point we need to commit the transaction because we had + * btrfs_need_log_full_commit() or some other error. + * + * If we didn't do a full sync we have to stop the trans handle, wait on + * the ordered extents, start it again and commit the transaction. If + * we attempt to wait on the ordered extents here we could deadlock with + * something like fallocate() that is holding the extent lock trying to + * start a transaction while some other thread is trying to commit the + * transaction while we (fsync) are currently holding the transaction + * open. + */ + if (!full_sync) { + ret = btrfs_end_transaction(trans); + if (ret) + goto out; + ret = btrfs_wait_ordered_range(inode, start, len); + if (ret) + goto out; + + /* + * This is safe to use here because we're only interested in + * making sure the transaction that had the ordered extents is + * committed. We aren't waiting on anything past this point, + * we're purely getting the transaction and committing it. + */ + trans = btrfs_attach_transaction_barrier(root); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + + /* + * We committed the transaction and there's no currently + * running transaction, this means everything we care + * about made it to disk and we are done. + */ + if (ret == -ENOENT) + ret = 0; + goto out; + } + } + + ret = btrfs_commit_transaction(trans); +out: + ASSERT(list_empty(&ctx.list)); + ASSERT(list_empty(&ctx.conflict_inodes)); + err = file_check_and_advance_wb_err(file); + if (!ret) + ret = err; + return ret > 0 ? -EIO : ret; + +out_release_extents: + btrfs_release_log_ctx_extents(&ctx); + btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP); + goto out; +} + +static const struct vm_operations_struct btrfs_file_vm_ops = { + .fault = filemap_fault, + .map_pages = filemap_map_pages, + .page_mkwrite = btrfs_page_mkwrite, +}; + +static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct address_space *mapping = filp->f_mapping; + + if (!mapping->a_ops->read_folio) + return -ENOEXEC; + + file_accessed(filp); + vma->vm_ops = &btrfs_file_vm_ops; + + return 0; +} + +static int hole_mergeable(struct btrfs_inode *inode, struct extent_buffer *leaf, + int slot, u64 start, u64 end) +{ + struct btrfs_file_extent_item *fi; + struct btrfs_key key; + + if (slot < 0 || slot >= btrfs_header_nritems(leaf)) + return 0; + + btrfs_item_key_to_cpu(leaf, &key, slot); + if (key.objectid != btrfs_ino(inode) || + key.type != BTRFS_EXTENT_DATA_KEY) + return 0; + + fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); + + if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG) + return 0; + + if (btrfs_file_extent_disk_bytenr(leaf, fi)) + return 0; + + if (key.offset == end) + return 1; + if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start) + return 1; + return 0; +} + +static int fill_holes(struct btrfs_trans_handle *trans, + struct btrfs_inode *inode, + struct btrfs_path *path, u64 offset, u64 end) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_root *root = inode->root; + struct extent_buffer *leaf; + struct btrfs_file_extent_item *fi; + struct extent_map *hole_em; + struct btrfs_key key; + int ret; + + if (btrfs_fs_incompat(fs_info, NO_HOLES)) + goto out; + + key.objectid = btrfs_ino(inode); + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = offset; + + ret = btrfs_search_slot(trans, root, &key, path, 0, 1); + if (ret <= 0) { + /* + * We should have dropped this offset, so if we find it then + * something has gone horribly wrong. + */ + if (ret == 0) + ret = -EINVAL; + return ret; + } + + leaf = path->nodes[0]; + if (hole_mergeable(inode, leaf, path->slots[0] - 1, offset, end)) { + u64 num_bytes; + + path->slots[0]--; + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + + end - offset; + btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes); + btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes); + btrfs_set_file_extent_offset(leaf, fi, 0); + btrfs_set_file_extent_generation(leaf, fi, trans->transid); + btrfs_mark_buffer_dirty(leaf); + goto out; + } + + if (hole_mergeable(inode, leaf, path->slots[0], offset, end)) { + u64 num_bytes; + + key.offset = offset; + btrfs_set_item_key_safe(fs_info, path, &key); + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end - + offset; + btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes); + btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes); + btrfs_set_file_extent_offset(leaf, fi, 0); + btrfs_set_file_extent_generation(leaf, fi, trans->transid); + btrfs_mark_buffer_dirty(leaf); + goto out; + } + btrfs_release_path(path); + + ret = btrfs_insert_hole_extent(trans, root, btrfs_ino(inode), offset, + end - offset); + if (ret) + return ret; + +out: + btrfs_release_path(path); + + hole_em = alloc_extent_map(); + if (!hole_em) { + btrfs_drop_extent_map_range(inode, offset, end - 1, false); + btrfs_set_inode_full_sync(inode); + } else { + hole_em->start = offset; + hole_em->len = end - offset; + hole_em->ram_bytes = hole_em->len; + hole_em->orig_start = offset; + + hole_em->block_start = EXTENT_MAP_HOLE; + hole_em->block_len = 0; + hole_em->orig_block_len = 0; + hole_em->compress_type = BTRFS_COMPRESS_NONE; + hole_em->generation = trans->transid; + + ret = btrfs_replace_extent_map_range(inode, hole_em, true); + free_extent_map(hole_em); + if (ret) + btrfs_set_inode_full_sync(inode); + } + + return 0; +} + +/* + * Find a hole extent on given inode and change start/len to the end of hole + * extent.(hole/vacuum extent whose em->start <= start && + * em->start + em->len > start) + * When a hole extent is found, return 1 and modify start/len. + */ +static int find_first_non_hole(struct btrfs_inode *inode, u64 *start, u64 *len) +{ + struct btrfs_fs_info *fs_info = inode->root->fs_info; + struct extent_map *em; + int ret = 0; + + em = btrfs_get_extent(inode, NULL, 0, + round_down(*start, fs_info->sectorsize), + round_up(*len, fs_info->sectorsize)); + if (IS_ERR(em)) + return PTR_ERR(em); + + /* Hole or vacuum extent(only exists in no-hole mode) */ + if (em->block_start == EXTENT_MAP_HOLE) { + ret = 1; + *len = em->start + em->len > *start + *len ? + 0 : *start + *len - em->start - em->len; + *start = em->start + em->len; + } + free_extent_map(em); + return ret; +} + +static void btrfs_punch_hole_lock_range(struct inode *inode, + const u64 lockstart, + const u64 lockend, + struct extent_state **cached_state) +{ + /* + * For subpage case, if the range is not at page boundary, we could + * have pages at the leading/tailing part of the range. + * This could lead to dead loop since filemap_range_has_page() + * will always return true. + * So here we need to do extra page alignment for + * filemap_range_has_page(). + */ + const u64 page_lockstart = round_up(lockstart, PAGE_SIZE); + const u64 page_lockend = round_down(lockend + 1, PAGE_SIZE) - 1; + + while (1) { + truncate_pagecache_range(inode, lockstart, lockend); + + lock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend, + cached_state); + /* + * We can't have ordered extents in the range, nor dirty/writeback + * pages, because we have locked the inode's VFS lock in exclusive + * mode, we have locked the inode's i_mmap_lock in exclusive mode, + * we have flushed all delalloc in the range and we have waited + * for any ordered extents in the range to complete. + * We can race with anyone reading pages from this range, so after + * locking the range check if we have pages in the range, and if + * we do, unlock the range and retry. + */ + if (!filemap_range_has_page(inode->i_mapping, page_lockstart, + page_lockend)) + break; + + unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend, + cached_state); + } + + btrfs_assert_inode_range_clean(BTRFS_I(inode), lockstart, lockend); +} + +static int btrfs_insert_replace_extent(struct btrfs_trans_handle *trans, + struct btrfs_inode *inode, + struct btrfs_path *path, + struct btrfs_replace_extent_info *extent_info, + const u64 replace_len, + const u64 bytes_to_drop) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_root *root = inode->root; + struct btrfs_file_extent_item *extent; + struct extent_buffer *leaf; + struct btrfs_key key; + int slot; + struct btrfs_ref ref = { 0 }; + int ret; + + if (replace_len == 0) + return 0; + + if (extent_info->disk_offset == 0 && + btrfs_fs_incompat(fs_info, NO_HOLES)) { + btrfs_update_inode_bytes(inode, 0, bytes_to_drop); + return 0; + } + + key.objectid = btrfs_ino(inode); + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = extent_info->file_offset; + ret = btrfs_insert_empty_item(trans, root, path, &key, + sizeof(struct btrfs_file_extent_item)); + if (ret) + return ret; + leaf = path->nodes[0]; + slot = path->slots[0]; + write_extent_buffer(leaf, extent_info->extent_buf, + btrfs_item_ptr_offset(leaf, slot), + sizeof(struct btrfs_file_extent_item)); + extent = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); + ASSERT(btrfs_file_extent_type(leaf, extent) != BTRFS_FILE_EXTENT_INLINE); + btrfs_set_file_extent_offset(leaf, extent, extent_info->data_offset); + btrfs_set_file_extent_num_bytes(leaf, extent, replace_len); + if (extent_info->is_new_extent) + btrfs_set_file_extent_generation(leaf, extent, trans->transid); + btrfs_mark_buffer_dirty(leaf); + btrfs_release_path(path); + + ret = btrfs_inode_set_file_extent_range(inode, extent_info->file_offset, + replace_len); + if (ret) + return ret; + + /* If it's a hole, nothing more needs to be done. */ + if (extent_info->disk_offset == 0) { + btrfs_update_inode_bytes(inode, 0, bytes_to_drop); + return 0; + } + + btrfs_update_inode_bytes(inode, replace_len, bytes_to_drop); + + if (extent_info->is_new_extent && extent_info->insertions == 0) { + key.objectid = extent_info->disk_offset; + key.type = BTRFS_EXTENT_ITEM_KEY; + key.offset = extent_info->disk_len; + ret = btrfs_alloc_reserved_file_extent(trans, root, + btrfs_ino(inode), + extent_info->file_offset, + extent_info->qgroup_reserved, + &key); + } else { + u64 ref_offset; + + btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, + extent_info->disk_offset, + extent_info->disk_len, 0); + ref_offset = extent_info->file_offset - extent_info->data_offset; + btrfs_init_data_ref(&ref, root->root_key.objectid, + btrfs_ino(inode), ref_offset, 0, false); + ret = btrfs_inc_extent_ref(trans, &ref); + } + + extent_info->insertions++; + + return ret; +} + +/* + * The respective range must have been previously locked, as well as the inode. + * The end offset is inclusive (last byte of the range). + * @extent_info is NULL for fallocate's hole punching and non-NULL when replacing + * the file range with an extent. + * When not punching a hole, we don't want to end up in a state where we dropped + * extents without inserting a new one, so we must abort the transaction to avoid + * a corruption. + */ +int btrfs_replace_file_extents(struct btrfs_inode *inode, + struct btrfs_path *path, const u64 start, + const u64 end, + struct btrfs_replace_extent_info *extent_info, + struct btrfs_trans_handle **trans_out) +{ + struct btrfs_drop_extents_args drop_args = { 0 }; + struct btrfs_root *root = inode->root; + struct btrfs_fs_info *fs_info = root->fs_info; + u64 min_size = btrfs_calc_insert_metadata_size(fs_info, 1); + u64 ino_size = round_up(inode->vfs_inode.i_size, fs_info->sectorsize); + struct btrfs_trans_handle *trans = NULL; + struct btrfs_block_rsv *rsv; + unsigned int rsv_count; + u64 cur_offset; + u64 len = end - start; + int ret = 0; + + if (end <= start) + return -EINVAL; + + rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP); + if (!rsv) { + ret = -ENOMEM; + goto out; + } + rsv->size = btrfs_calc_insert_metadata_size(fs_info, 1); + rsv->failfast = true; + + /* + * 1 - update the inode + * 1 - removing the extents in the range + * 1 - adding the hole extent if no_holes isn't set or if we are + * replacing the range with a new extent + */ + if (!btrfs_fs_incompat(fs_info, NO_HOLES) || extent_info) + rsv_count = 3; + else + rsv_count = 2; + + trans = btrfs_start_transaction(root, rsv_count); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + trans = NULL; + goto out_free; + } + + ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv, + min_size, false); + if (WARN_ON(ret)) + goto out_trans; + trans->block_rsv = rsv; + + cur_offset = start; + drop_args.path = path; + drop_args.end = end + 1; + drop_args.drop_cache = true; + while (cur_offset < end) { + drop_args.start = cur_offset; + ret = btrfs_drop_extents(trans, root, inode, &drop_args); + /* If we are punching a hole decrement the inode's byte count */ + if (!extent_info) + btrfs_update_inode_bytes(inode, 0, + drop_args.bytes_found); + if (ret != -ENOSPC) { + /* + * The only time we don't want to abort is if we are + * attempting to clone a partial inline extent, in which + * case we'll get EOPNOTSUPP. However if we aren't + * clone we need to abort no matter what, because if we + * got EOPNOTSUPP via prealloc then we messed up and + * need to abort. + */ + if (ret && + (ret != -EOPNOTSUPP || + (extent_info && extent_info->is_new_extent))) + btrfs_abort_transaction(trans, ret); + break; + } + + trans->block_rsv = &fs_info->trans_block_rsv; + + if (!extent_info && cur_offset < drop_args.drop_end && + cur_offset < ino_size) { + ret = fill_holes(trans, inode, path, cur_offset, + drop_args.drop_end); + if (ret) { + /* + * If we failed then we didn't insert our hole + * entries for the area we dropped, so now the + * fs is corrupted, so we must abort the + * transaction. + */ + btrfs_abort_transaction(trans, ret); + break; + } + } else if (!extent_info && cur_offset < drop_args.drop_end) { + /* + * We are past the i_size here, but since we didn't + * insert holes we need to clear the mapped area so we + * know to not set disk_i_size in this area until a new + * file extent is inserted here. + */ + ret = btrfs_inode_clear_file_extent_range(inode, + cur_offset, + drop_args.drop_end - cur_offset); + if (ret) { + /* + * We couldn't clear our area, so we could + * presumably adjust up and corrupt the fs, so + * we need to abort. + */ + btrfs_abort_transaction(trans, ret); + break; + } + } + + if (extent_info && + drop_args.drop_end > extent_info->file_offset) { + u64 replace_len = drop_args.drop_end - + extent_info->file_offset; + + ret = btrfs_insert_replace_extent(trans, inode, path, + extent_info, replace_len, + drop_args.bytes_found); + if (ret) { + btrfs_abort_transaction(trans, ret); + break; + } + extent_info->data_len -= replace_len; + extent_info->data_offset += replace_len; + extent_info->file_offset += replace_len; + } + + /* + * We are releasing our handle on the transaction, balance the + * dirty pages of the btree inode and flush delayed items, and + * then get a new transaction handle, which may now point to a + * new transaction in case someone else may have committed the + * transaction we used to replace/drop file extent items. So + * bump the inode's iversion and update mtime and ctime except + * if we are called from a dedupe context. This is because a + * power failure/crash may happen after the transaction is + * committed and before we finish replacing/dropping all the + * file extent items we need. + */ + inode_inc_iversion(&inode->vfs_inode); + + if (!extent_info || extent_info->update_times) { + inode->vfs_inode.i_mtime = current_time(&inode->vfs_inode); + inode->vfs_inode.i_ctime = inode->vfs_inode.i_mtime; + } + + ret = btrfs_update_inode(trans, root, inode); + if (ret) + break; + + btrfs_end_transaction(trans); + btrfs_btree_balance_dirty(fs_info); + + trans = btrfs_start_transaction(root, rsv_count); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + trans = NULL; + break; + } + + ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, + rsv, min_size, false); + if (WARN_ON(ret)) + break; + trans->block_rsv = rsv; + + cur_offset = drop_args.drop_end; + len = end - cur_offset; + if (!extent_info && len) { + ret = find_first_non_hole(inode, &cur_offset, &len); + if (unlikely(ret < 0)) + break; + if (ret && !len) { + ret = 0; + break; + } + } + } + + /* + * If we were cloning, force the next fsync to be a full one since we + * we replaced (or just dropped in the case of cloning holes when + * NO_HOLES is enabled) file extent items and did not setup new extent + * maps for the replacement extents (or holes). + */ + if (extent_info && !extent_info->is_new_extent) + btrfs_set_inode_full_sync(inode); + + if (ret) + goto out_trans; + + trans->block_rsv = &fs_info->trans_block_rsv; + /* + * If we are using the NO_HOLES feature we might have had already an + * hole that overlaps a part of the region [lockstart, lockend] and + * ends at (or beyond) lockend. Since we have no file extent items to + * represent holes, drop_end can be less than lockend and so we must + * make sure we have an extent map representing the existing hole (the + * call to __btrfs_drop_extents() might have dropped the existing extent + * map representing the existing hole), otherwise the fast fsync path + * will not record the existence of the hole region + * [existing_hole_start, lockend]. + */ + if (drop_args.drop_end <= end) + drop_args.drop_end = end + 1; + /* + * Don't insert file hole extent item if it's for a range beyond eof + * (because it's useless) or if it represents a 0 bytes range (when + * cur_offset == drop_end). + */ + if (!extent_info && cur_offset < ino_size && + cur_offset < drop_args.drop_end) { + ret = fill_holes(trans, inode, path, cur_offset, + drop_args.drop_end); + if (ret) { + /* Same comment as above. */ + btrfs_abort_transaction(trans, ret); + goto out_trans; + } + } else if (!extent_info && cur_offset < drop_args.drop_end) { + /* See the comment in the loop above for the reasoning here. */ + ret = btrfs_inode_clear_file_extent_range(inode, cur_offset, + drop_args.drop_end - cur_offset); + if (ret) { + btrfs_abort_transaction(trans, ret); + goto out_trans; + } + + } + if (extent_info) { + ret = btrfs_insert_replace_extent(trans, inode, path, + extent_info, extent_info->data_len, + drop_args.bytes_found); + if (ret) { + btrfs_abort_transaction(trans, ret); + goto out_trans; + } + } + +out_trans: + if (!trans) + goto out_free; + + trans->block_rsv = &fs_info->trans_block_rsv; + if (ret) + btrfs_end_transaction(trans); + else + *trans_out = trans; +out_free: + btrfs_free_block_rsv(fs_info, rsv); +out: + return ret; +} + +static int btrfs_punch_hole(struct file *file, loff_t offset, loff_t len) +{ + struct inode *inode = file_inode(file); + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + struct btrfs_root *root = BTRFS_I(inode)->root; + struct extent_state *cached_state = NULL; + struct btrfs_path *path; + struct btrfs_trans_handle *trans = NULL; + u64 lockstart; + u64 lockend; + u64 tail_start; + u64 tail_len; + u64 orig_start = offset; + int ret = 0; + bool same_block; + u64 ino_size; + bool truncated_block = false; + bool updated_inode = false; + + btrfs_inode_lock(inode, BTRFS_ILOCK_MMAP); + + ret = btrfs_wait_ordered_range(inode, offset, len); + if (ret) + goto out_only_mutex; + + ino_size = round_up(inode->i_size, fs_info->sectorsize); + ret = find_first_non_hole(BTRFS_I(inode), &offset, &len); + if (ret < 0) + goto out_only_mutex; + if (ret && !len) { + /* Already in a large hole */ + ret = 0; + goto out_only_mutex; + } + + ret = file_modified(file); + if (ret) + goto out_only_mutex; + + lockstart = round_up(offset, fs_info->sectorsize); + lockend = round_down(offset + len, fs_info->sectorsize) - 1; + same_block = (BTRFS_BYTES_TO_BLKS(fs_info, offset)) + == (BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1)); + /* + * We needn't truncate any block which is beyond the end of the file + * because we are sure there is no data there. + */ + /* + * Only do this if we are in the same block and we aren't doing the + * entire block. + */ + if (same_block && len < fs_info->sectorsize) { + if (offset < ino_size) { + truncated_block = true; + ret = btrfs_truncate_block(BTRFS_I(inode), offset, len, + 0); + } else { + ret = 0; + } + goto out_only_mutex; + } + + /* zero back part of the first block */ + if (offset < ino_size) { + truncated_block = true; + ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0); + if (ret) { + btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP); + return ret; + } + } + + /* Check the aligned pages after the first unaligned page, + * if offset != orig_start, which means the first unaligned page + * including several following pages are already in holes, + * the extra check can be skipped */ + if (offset == orig_start) { + /* after truncate page, check hole again */ + len = offset + len - lockstart; + offset = lockstart; + ret = find_first_non_hole(BTRFS_I(inode), &offset, &len); + if (ret < 0) + goto out_only_mutex; + if (ret && !len) { + ret = 0; + goto out_only_mutex; + } + lockstart = offset; + } + + /* Check the tail unaligned part is in a hole */ + tail_start = lockend + 1; + tail_len = offset + len - tail_start; + if (tail_len) { + ret = find_first_non_hole(BTRFS_I(inode), &tail_start, &tail_len); + if (unlikely(ret < 0)) + goto out_only_mutex; + if (!ret) { + /* zero the front end of the last page */ + if (tail_start + tail_len < ino_size) { + truncated_block = true; + ret = btrfs_truncate_block(BTRFS_I(inode), + tail_start + tail_len, + 0, 1); + if (ret) + goto out_only_mutex; + } + } + } + + if (lockend < lockstart) { + ret = 0; + goto out_only_mutex; + } + + btrfs_punch_hole_lock_range(inode, lockstart, lockend, &cached_state); + + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + + ret = btrfs_replace_file_extents(BTRFS_I(inode), path, lockstart, + lockend, NULL, &trans); + btrfs_free_path(path); + if (ret) + goto out; + + ASSERT(trans != NULL); + inode_inc_iversion(inode); + inode->i_mtime = current_time(inode); + inode->i_ctime = inode->i_mtime; + ret = btrfs_update_inode(trans, root, BTRFS_I(inode)); + updated_inode = true; + btrfs_end_transaction(trans); + btrfs_btree_balance_dirty(fs_info); +out: + unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend, + &cached_state); +out_only_mutex: + if (!updated_inode && truncated_block && !ret) { + /* + * If we only end up zeroing part of a page, we still need to + * update the inode item, so that all the time fields are + * updated as well as the necessary btrfs inode in memory fields + * for detecting, at fsync time, if the inode isn't yet in the + * log tree or it's there but not up to date. + */ + struct timespec64 now = current_time(inode); + + inode_inc_iversion(inode); + inode->i_mtime = now; + inode->i_ctime = now; + trans = btrfs_start_transaction(root, 1); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + } else { + int ret2; + + ret = btrfs_update_inode(trans, root, BTRFS_I(inode)); + ret2 = btrfs_end_transaction(trans); + if (!ret) + ret = ret2; + } + } + btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP); + return ret; +} + +/* Helper structure to record which range is already reserved */ +struct falloc_range { + struct list_head list; + u64 start; + u64 len; +}; + +/* + * Helper function to add falloc range + * + * Caller should have locked the larger range of extent containing + * [start, len) + */ +static int add_falloc_range(struct list_head *head, u64 start, u64 len) +{ + struct falloc_range *range = NULL; + + if (!list_empty(head)) { + /* + * As fallocate iterates by bytenr order, we only need to check + * the last range. + */ + range = list_last_entry(head, struct falloc_range, list); + if (range->start + range->len == start) { + range->len += len; + return 0; + } + } + + range = kmalloc(sizeof(*range), GFP_KERNEL); + if (!range) + return -ENOMEM; + range->start = start; + range->len = len; + list_add_tail(&range->list, head); + return 0; +} + +static int btrfs_fallocate_update_isize(struct inode *inode, + const u64 end, + const int mode) +{ + struct btrfs_trans_handle *trans; + struct btrfs_root *root = BTRFS_I(inode)->root; + int ret; + int ret2; + + if (mode & FALLOC_FL_KEEP_SIZE || end <= i_size_read(inode)) + return 0; + + trans = btrfs_start_transaction(root, 1); + if (IS_ERR(trans)) + return PTR_ERR(trans); + + inode->i_ctime = current_time(inode); + i_size_write(inode, end); + btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0); + ret = btrfs_update_inode(trans, root, BTRFS_I(inode)); + ret2 = btrfs_end_transaction(trans); + + return ret ? ret : ret2; +} + +enum { + RANGE_BOUNDARY_WRITTEN_EXTENT, + RANGE_BOUNDARY_PREALLOC_EXTENT, + RANGE_BOUNDARY_HOLE, +}; + +static int btrfs_zero_range_check_range_boundary(struct btrfs_inode *inode, + u64 offset) +{ + const u64 sectorsize = inode->root->fs_info->sectorsize; + struct extent_map *em; + int ret; + + offset = round_down(offset, sectorsize); + em = btrfs_get_extent(inode, NULL, 0, offset, sectorsize); + if (IS_ERR(em)) + return PTR_ERR(em); + + if (em->block_start == EXTENT_MAP_HOLE) + ret = RANGE_BOUNDARY_HOLE; + else if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) + ret = RANGE_BOUNDARY_PREALLOC_EXTENT; + else + ret = RANGE_BOUNDARY_WRITTEN_EXTENT; + + free_extent_map(em); + return ret; +} + +static int btrfs_zero_range(struct inode *inode, + loff_t offset, + loff_t len, + const int mode) +{ + struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info; + struct extent_map *em; + struct extent_changeset *data_reserved = NULL; + int ret; + u64 alloc_hint = 0; + const u64 sectorsize = fs_info->sectorsize; + u64 alloc_start = round_down(offset, sectorsize); + u64 alloc_end = round_up(offset + len, sectorsize); + u64 bytes_to_reserve = 0; + bool space_reserved = false; + + em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start, + alloc_end - alloc_start); + if (IS_ERR(em)) { + ret = PTR_ERR(em); + goto out; + } + + /* + * Avoid hole punching and extent allocation for some cases. More cases + * could be considered, but these are unlikely common and we keep things + * as simple as possible for now. Also, intentionally, if the target + * range contains one or more prealloc extents together with regular + * extents and holes, we drop all the existing extents and allocate a + * new prealloc extent, so that we get a larger contiguous disk extent. + */ + if (em->start <= alloc_start && + test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) { + const u64 em_end = em->start + em->len; + + if (em_end >= offset + len) { + /* + * The whole range is already a prealloc extent, + * do nothing except updating the inode's i_size if + * needed. + */ + free_extent_map(em); + ret = btrfs_fallocate_update_isize(inode, offset + len, + mode); + goto out; + } + /* + * Part of the range is already a prealloc extent, so operate + * only on the remaining part of the range. + */ + alloc_start = em_end; + ASSERT(IS_ALIGNED(alloc_start, sectorsize)); + len = offset + len - alloc_start; + offset = alloc_start; + alloc_hint = em->block_start + em->len; + } + free_extent_map(em); + + if (BTRFS_BYTES_TO_BLKS(fs_info, offset) == + BTRFS_BYTES_TO_BLKS(fs_info, offset + len - 1)) { + em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, alloc_start, + sectorsize); + if (IS_ERR(em)) { + ret = PTR_ERR(em); + goto out; + } + + if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) { + free_extent_map(em); + ret = btrfs_fallocate_update_isize(inode, offset + len, + mode); + goto out; + } + if (len < sectorsize && em->block_start != EXTENT_MAP_HOLE) { + free_extent_map(em); + ret = btrfs_truncate_block(BTRFS_I(inode), offset, len, + 0); + if (!ret) + ret = btrfs_fallocate_update_isize(inode, + offset + len, + mode); + return ret; + } + free_extent_map(em); + alloc_start = round_down(offset, sectorsize); + alloc_end = alloc_start + sectorsize; + goto reserve_space; + } + + alloc_start = round_up(offset, sectorsize); + alloc_end = round_down(offset + len, sectorsize); + + /* + * For unaligned ranges, check the pages at the boundaries, they might + * map to an extent, in which case we need to partially zero them, or + * they might map to a hole, in which case we need our allocation range + * to cover them. + */ + if (!IS_ALIGNED(offset, sectorsize)) { + ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode), + offset); + if (ret < 0) + goto out; + if (ret == RANGE_BOUNDARY_HOLE) { + alloc_start = round_down(offset, sectorsize); + ret = 0; + } else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) { + ret = btrfs_truncate_block(BTRFS_I(inode), offset, 0, 0); + if (ret) + goto out; + } else { + ret = 0; + } + } + + if (!IS_ALIGNED(offset + len, sectorsize)) { + ret = btrfs_zero_range_check_range_boundary(BTRFS_I(inode), + offset + len); + if (ret < 0) + goto out; + if (ret == RANGE_BOUNDARY_HOLE) { + alloc_end = round_up(offset + len, sectorsize); + ret = 0; + } else if (ret == RANGE_BOUNDARY_WRITTEN_EXTENT) { + ret = btrfs_truncate_block(BTRFS_I(inode), offset + len, + 0, 1); + if (ret) + goto out; + } else { + ret = 0; + } + } + +reserve_space: + if (alloc_start < alloc_end) { + struct extent_state *cached_state = NULL; + const u64 lockstart = alloc_start; + const u64 lockend = alloc_end - 1; + + bytes_to_reserve = alloc_end - alloc_start; + ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode), + bytes_to_reserve); + if (ret < 0) + goto out; + space_reserved = true; + btrfs_punch_hole_lock_range(inode, lockstart, lockend, + &cached_state); + ret = btrfs_qgroup_reserve_data(BTRFS_I(inode), &data_reserved, + alloc_start, bytes_to_reserve); + if (ret) { + unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, + lockend, &cached_state); + goto out; + } + ret = btrfs_prealloc_file_range(inode, mode, alloc_start, + alloc_end - alloc_start, + i_blocksize(inode), + offset + len, &alloc_hint); + unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend, + &cached_state); + /* btrfs_prealloc_file_range releases reserved space on error */ + if (ret) { + space_reserved = false; + goto out; + } + } + ret = btrfs_fallocate_update_isize(inode, offset + len, mode); + out: + if (ret && space_reserved) + btrfs_free_reserved_data_space(BTRFS_I(inode), data_reserved, + alloc_start, bytes_to_reserve); + extent_changeset_free(data_reserved); + + return ret; +} + +static long btrfs_fallocate(struct file *file, int mode, + loff_t offset, loff_t len) +{ + struct inode *inode = file_inode(file); + struct extent_state *cached_state = NULL; + struct extent_changeset *data_reserved = NULL; + struct falloc_range *range; + struct falloc_range *tmp; + struct list_head reserve_list; + u64 cur_offset; + u64 last_byte; + u64 alloc_start; + u64 alloc_end; + u64 alloc_hint = 0; + u64 locked_end; + u64 actual_end = 0; + u64 data_space_needed = 0; + u64 data_space_reserved = 0; + u64 qgroup_reserved = 0; + struct extent_map *em; + int blocksize = BTRFS_I(inode)->root->fs_info->sectorsize; + int ret; + + /* Do not allow fallocate in ZONED mode */ + if (btrfs_is_zoned(btrfs_sb(inode->i_sb))) + return -EOPNOTSUPP; + + alloc_start = round_down(offset, blocksize); + alloc_end = round_up(offset + len, blocksize); + cur_offset = alloc_start; + + /* Make sure we aren't being give some crap mode */ + if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | + FALLOC_FL_ZERO_RANGE)) + return -EOPNOTSUPP; + + if (mode & FALLOC_FL_PUNCH_HOLE) + return btrfs_punch_hole(file, offset, len); + + btrfs_inode_lock(inode, BTRFS_ILOCK_MMAP); + + if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) { + ret = inode_newsize_ok(inode, offset + len); + if (ret) + goto out; + } + + ret = file_modified(file); + if (ret) + goto out; + + /* + * TODO: Move these two operations after we have checked + * accurate reserved space, or fallocate can still fail but + * with page truncated or size expanded. + * + * But that's a minor problem and won't do much harm BTW. + */ + if (alloc_start > inode->i_size) { + ret = btrfs_cont_expand(BTRFS_I(inode), i_size_read(inode), + alloc_start); + if (ret) + goto out; + } else if (offset + len > inode->i_size) { + /* + * If we are fallocating from the end of the file onward we + * need to zero out the end of the block if i_size lands in the + * middle of a block. + */ + ret = btrfs_truncate_block(BTRFS_I(inode), inode->i_size, 0, 0); + if (ret) + goto out; + } + + /* + * We have locked the inode at the VFS level (in exclusive mode) and we + * have locked the i_mmap_lock lock (in exclusive mode). Now before + * locking the file range, flush all dealloc in the range and wait for + * all ordered extents in the range to complete. After this we can lock + * the file range and, due to the previous locking we did, we know there + * can't be more delalloc or ordered extents in the range. + */ + ret = btrfs_wait_ordered_range(inode, alloc_start, + alloc_end - alloc_start); + if (ret) + goto out; + + if (mode & FALLOC_FL_ZERO_RANGE) { + ret = btrfs_zero_range(inode, offset, len, mode); + btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP); + return ret; + } + + locked_end = alloc_end - 1; + lock_extent(&BTRFS_I(inode)->io_tree, alloc_start, locked_end, + &cached_state); + + btrfs_assert_inode_range_clean(BTRFS_I(inode), alloc_start, locked_end); + + /* First, check if we exceed the qgroup limit */ + INIT_LIST_HEAD(&reserve_list); + while (cur_offset < alloc_end) { + em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset, + alloc_end - cur_offset); + if (IS_ERR(em)) { + ret = PTR_ERR(em); + break; + } + last_byte = min(extent_map_end(em), alloc_end); + actual_end = min_t(u64, extent_map_end(em), offset + len); + last_byte = ALIGN(last_byte, blocksize); + if (em->block_start == EXTENT_MAP_HOLE || + (cur_offset >= inode->i_size && + !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) { + const u64 range_len = last_byte - cur_offset; + + ret = add_falloc_range(&reserve_list, cur_offset, range_len); + if (ret < 0) { + free_extent_map(em); + break; + } + ret = btrfs_qgroup_reserve_data(BTRFS_I(inode), + &data_reserved, cur_offset, range_len); + if (ret < 0) { + free_extent_map(em); + break; + } + qgroup_reserved += range_len; + data_space_needed += range_len; + } + free_extent_map(em); + cur_offset = last_byte; + } + + if (!ret && data_space_needed > 0) { + /* + * We are safe to reserve space here as we can't have delalloc + * in the range, see above. + */ + ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode), + data_space_needed); + if (!ret) + data_space_reserved = data_space_needed; + } + + /* + * If ret is still 0, means we're OK to fallocate. + * Or just cleanup the list and exit. + */ + list_for_each_entry_safe(range, tmp, &reserve_list, list) { + if (!ret) { + ret = btrfs_prealloc_file_range(inode, mode, + range->start, + range->len, i_blocksize(inode), + offset + len, &alloc_hint); + /* + * btrfs_prealloc_file_range() releases space even + * if it returns an error. + */ + data_space_reserved -= range->len; + qgroup_reserved -= range->len; + } else if (data_space_reserved > 0) { + btrfs_free_reserved_data_space(BTRFS_I(inode), + data_reserved, range->start, + range->len); + data_space_reserved -= range->len; + qgroup_reserved -= range->len; + } else if (qgroup_reserved > 0) { + btrfs_qgroup_free_data(BTRFS_I(inode), data_reserved, + range->start, range->len, NULL); + qgroup_reserved -= range->len; + } + list_del(&range->list); + kfree(range); + } + if (ret < 0) + goto out_unlock; + + /* + * We didn't need to allocate any more space, but we still extended the + * size of the file so we need to update i_size and the inode item. + */ + ret = btrfs_fallocate_update_isize(inode, actual_end, mode); +out_unlock: + unlock_extent(&BTRFS_I(inode)->io_tree, alloc_start, locked_end, + &cached_state); +out: + btrfs_inode_unlock(inode, BTRFS_ILOCK_MMAP); + extent_changeset_free(data_reserved); + return ret; +} + +/* + * Helper for btrfs_find_delalloc_in_range(). Find a subrange in a given range + * that has unflushed and/or flushing delalloc. There might be other adjacent + * subranges after the one it found, so btrfs_find_delalloc_in_range() keeps + * looping while it gets adjacent subranges, and merging them together. + */ +static bool find_delalloc_subrange(struct btrfs_inode *inode, u64 start, u64 end, + u64 *delalloc_start_ret, u64 *delalloc_end_ret) +{ + const u64 len = end + 1 - start; + struct extent_map_tree *em_tree = &inode->extent_tree; + struct extent_map *em; + u64 em_end; + u64 delalloc_len; + + /* + * Search the io tree first for EXTENT_DELALLOC. If we find any, it + * means we have delalloc (dirty pages) for which writeback has not + * started yet. + */ + *delalloc_start_ret = start; + delalloc_len = count_range_bits(&inode->io_tree, delalloc_start_ret, end, + len, EXTENT_DELALLOC, 1); + /* + * If delalloc was found then *delalloc_start_ret has a sector size + * aligned value (rounded down). + */ + if (delalloc_len > 0) + *delalloc_end_ret = *delalloc_start_ret + delalloc_len - 1; + + /* + * Now also check if there's any extent map in the range that does not + * map to a hole or prealloc extent. We do this because: + * + * 1) When delalloc is flushed, the file range is locked, we clear the + * EXTENT_DELALLOC bit from the io tree and create an extent map for + * an allocated extent. So we might just have been called after + * delalloc is flushed and before the ordered extent completes and + * inserts the new file extent item in the subvolume's btree; + * + * 2) We may have an extent map created by flushing delalloc for a + * subrange that starts before the subrange we found marked with + * EXTENT_DELALLOC in the io tree. + */ + read_lock(&em_tree->lock); + em = lookup_extent_mapping(em_tree, start, len); + if (!em) { + read_unlock(&em_tree->lock); + return (delalloc_len > 0); + } + + /* extent_map_end() returns a non-inclusive end offset. */ + em_end = extent_map_end(em); + + /* + * If we have a hole/prealloc extent map, check the next one if this one + * ends before our range's end. + */ + if ((em->block_start == EXTENT_MAP_HOLE || + test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) && em_end < end) { + struct extent_map *next_em; + + next_em = btrfs_next_extent_map(em_tree, em); + free_extent_map(em); + + /* + * There's no next extent map or the next one starts beyond our + * range, return the range found in the io tree (if any). + */ + if (!next_em || next_em->start > end) { + read_unlock(&em_tree->lock); + free_extent_map(next_em); + return (delalloc_len > 0); + } + + em_end = extent_map_end(next_em); + em = next_em; + } + + read_unlock(&em_tree->lock); + + /* + * We have a hole or prealloc extent that ends at or beyond our range's + * end, return the range found in the io tree (if any). + */ + if (em->block_start == EXTENT_MAP_HOLE || + test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) { + free_extent_map(em); + return (delalloc_len > 0); + } + + /* + * We don't have any range as EXTENT_DELALLOC in the io tree, so the + * extent map is the only subrange representing delalloc. + */ + if (delalloc_len == 0) { + *delalloc_start_ret = em->start; + *delalloc_end_ret = min(end, em_end - 1); + free_extent_map(em); + return true; + } + + /* + * The extent map represents a delalloc range that starts before the + * delalloc range we found in the io tree. + */ + if (em->start < *delalloc_start_ret) { + *delalloc_start_ret = em->start; + /* + * If the ranges are adjacent, return a combined range. + * Otherwise return the extent map's range. + */ + if (em_end < *delalloc_start_ret) + *delalloc_end_ret = min(end, em_end - 1); + + free_extent_map(em); + return true; + } + + /* + * The extent map starts after the delalloc range we found in the io + * tree. If it's adjacent, return a combined range, otherwise return + * the range found in the io tree. + */ + if (*delalloc_end_ret + 1 == em->start) + *delalloc_end_ret = min(end, em_end - 1); + + free_extent_map(em); + return true; +} + +/* + * Check if there's delalloc in a given range. + * + * @inode: The inode. + * @start: The start offset of the range. It does not need to be + * sector size aligned. + * @end: The end offset (inclusive value) of the search range. + * It does not need to be sector size aligned. + * @delalloc_start_ret: Output argument, set to the start offset of the + * subrange found with delalloc (may not be sector size + * aligned). + * @delalloc_end_ret: Output argument, set to he end offset (inclusive value) + * of the subrange found with delalloc. + * + * Returns true if a subrange with delalloc is found within the given range, and + * if so it sets @delalloc_start_ret and @delalloc_end_ret with the start and + * end offsets of the subrange. + */ +bool btrfs_find_delalloc_in_range(struct btrfs_inode *inode, u64 start, u64 end, + u64 *delalloc_start_ret, u64 *delalloc_end_ret) +{ + u64 cur_offset = round_down(start, inode->root->fs_info->sectorsize); + u64 prev_delalloc_end = 0; + bool ret = false; + + while (cur_offset <= end) { + u64 delalloc_start; + u64 delalloc_end; + bool delalloc; + + delalloc = find_delalloc_subrange(inode, cur_offset, end, + &delalloc_start, + &delalloc_end); + if (!delalloc) + break; + + if (prev_delalloc_end == 0) { + /* First subrange found. */ + *delalloc_start_ret = max(delalloc_start, start); + *delalloc_end_ret = delalloc_end; + ret = true; + } else if (delalloc_start == prev_delalloc_end + 1) { + /* Subrange adjacent to the previous one, merge them. */ + *delalloc_end_ret = delalloc_end; + } else { + /* Subrange not adjacent to the previous one, exit. */ + break; + } + + prev_delalloc_end = delalloc_end; + cur_offset = delalloc_end + 1; + cond_resched(); + } + + return ret; +} + +/* + * Check if there's a hole or delalloc range in a range representing a hole (or + * prealloc extent) found in the inode's subvolume btree. + * + * @inode: The inode. + * @whence: Seek mode (SEEK_DATA or SEEK_HOLE). + * @start: Start offset of the hole region. It does not need to be sector + * size aligned. + * @end: End offset (inclusive value) of the hole region. It does not + * need to be sector size aligned. + * @start_ret: Return parameter, used to set the start of the subrange in the + * hole that matches the search criteria (seek mode), if such + * subrange is found (return value of the function is true). + * The value returned here may not be sector size aligned. + * + * Returns true if a subrange matching the given seek mode is found, and if one + * is found, it updates @start_ret with the start of the subrange. + */ +static bool find_desired_extent_in_hole(struct btrfs_inode *inode, int whence, + u64 start, u64 end, u64 *start_ret) +{ + u64 delalloc_start; + u64 delalloc_end; + bool delalloc; + + delalloc = btrfs_find_delalloc_in_range(inode, start, end, + &delalloc_start, &delalloc_end); + if (delalloc && whence == SEEK_DATA) { + *start_ret = delalloc_start; + return true; + } + + if (delalloc && whence == SEEK_HOLE) { + /* + * We found delalloc but it starts after out start offset. So we + * have a hole between our start offset and the delalloc start. + */ + if (start < delalloc_start) { + *start_ret = start; + return true; + } + /* + * Delalloc range starts at our start offset. + * If the delalloc range's length is smaller than our range, + * then it means we have a hole that starts where the delalloc + * subrange ends. + */ + if (delalloc_end < end) { + *start_ret = delalloc_end + 1; + return true; + } + + /* There's delalloc for the whole range. */ + return false; + } + + if (!delalloc && whence == SEEK_HOLE) { + *start_ret = start; + return true; + } + + /* + * No delalloc in the range and we are seeking for data. The caller has + * to iterate to the next extent item in the subvolume btree. + */ + return false; +} + +static loff_t find_desired_extent(struct btrfs_inode *inode, loff_t offset, + int whence) +{ + struct btrfs_fs_info *fs_info = inode->root->fs_info; + struct extent_state *cached_state = NULL; + const loff_t i_size = i_size_read(&inode->vfs_inode); + const u64 ino = btrfs_ino(inode); + struct btrfs_root *root = inode->root; + struct btrfs_path *path; + struct btrfs_key key; + u64 last_extent_end; + u64 lockstart; + u64 lockend; + u64 start; + int ret; + bool found = false; + + if (i_size == 0 || offset >= i_size) + return -ENXIO; + + /* + * Quick path. If the inode has no prealloc extents and its number of + * bytes used matches its i_size, then it can not have holes. + */ + if (whence == SEEK_HOLE && + !(inode->flags & BTRFS_INODE_PREALLOC) && + inode_get_bytes(&inode->vfs_inode) == i_size) + return i_size; + + /* + * offset can be negative, in this case we start finding DATA/HOLE from + * the very start of the file. + */ + start = max_t(loff_t, 0, offset); + + lockstart = round_down(start, fs_info->sectorsize); + lockend = round_up(i_size, fs_info->sectorsize); + if (lockend <= lockstart) + lockend = lockstart + fs_info->sectorsize; + lockend--; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + path->reada = READA_FORWARD; + + key.objectid = ino; + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = start; + + last_extent_end = lockstart; + + lock_extent(&inode->io_tree, lockstart, lockend, &cached_state); + + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) { + goto out; + } else if (ret > 0 && path->slots[0] > 0) { + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1); + if (key.objectid == ino && key.type == BTRFS_EXTENT_DATA_KEY) + path->slots[0]--; + } + + while (start < i_size) { + struct extent_buffer *leaf = path->nodes[0]; + struct btrfs_file_extent_item *extent; + u64 extent_end; + u8 type; + + if (path->slots[0] >= btrfs_header_nritems(leaf)) { + ret = btrfs_next_leaf(root, path); + if (ret < 0) + goto out; + else if (ret > 0) + break; + + leaf = path->nodes[0]; + } + + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + if (key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY) + break; + + extent_end = btrfs_file_extent_end(path); + + /* + * In the first iteration we may have a slot that points to an + * extent that ends before our start offset, so skip it. + */ + if (extent_end <= start) { + path->slots[0]++; + continue; + } + + /* We have an implicit hole, NO_HOLES feature is likely set. */ + if (last_extent_end < key.offset) { + u64 search_start = last_extent_end; + u64 found_start; + + /* + * First iteration, @start matches @offset and it's + * within the hole. + */ + if (start == offset) + search_start = offset; + + found = find_desired_extent_in_hole(inode, whence, + search_start, + key.offset - 1, + &found_start); + if (found) { + start = found_start; + break; + } + /* + * Didn't find data or a hole (due to delalloc) in the + * implicit hole range, so need to analyze the extent. + */ + } + + extent = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + type = btrfs_file_extent_type(leaf, extent); + + /* + * Can't access the extent's disk_bytenr field if this is an + * inline extent, since at that offset, it's where the extent + * data starts. + */ + if (type == BTRFS_FILE_EXTENT_PREALLOC || + (type == BTRFS_FILE_EXTENT_REG && + btrfs_file_extent_disk_bytenr(leaf, extent) == 0)) { + /* + * Explicit hole or prealloc extent, search for delalloc. + * A prealloc extent is treated like a hole. + */ + u64 search_start = key.offset; + u64 found_start; + + /* + * First iteration, @start matches @offset and it's + * within the hole. + */ + if (start == offset) + search_start = offset; + + found = find_desired_extent_in_hole(inode, whence, + search_start, + extent_end - 1, + &found_start); + if (found) { + start = found_start; + break; + } + /* + * Didn't find data or a hole (due to delalloc) in the + * implicit hole range, so need to analyze the next + * extent item. + */ + } else { + /* + * Found a regular or inline extent. + * If we are seeking for data, adjust the start offset + * and stop, we're done. + */ + if (whence == SEEK_DATA) { + start = max_t(u64, key.offset, offset); + found = true; + break; + } + /* + * Else, we are seeking for a hole, check the next file + * extent item. + */ + } + + start = extent_end; + last_extent_end = extent_end; + path->slots[0]++; + if (fatal_signal_pending(current)) { + ret = -EINTR; + goto out; + } + cond_resched(); + } + + /* We have an implicit hole from the last extent found up to i_size. */ + if (!found && start < i_size) { + found = find_desired_extent_in_hole(inode, whence, start, + i_size - 1, &start); + if (!found) + start = i_size; + } + +out: + unlock_extent(&inode->io_tree, lockstart, lockend, &cached_state); + btrfs_free_path(path); + + if (ret < 0) + return ret; + + if (whence == SEEK_DATA && start >= i_size) + return -ENXIO; + + return min_t(loff_t, start, i_size); +} + +static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence) +{ + struct inode *inode = file->f_mapping->host; + + switch (whence) { + default: + return generic_file_llseek(file, offset, whence); + case SEEK_DATA: + case SEEK_HOLE: + btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED); + offset = find_desired_extent(BTRFS_I(inode), offset, whence); + btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED); + break; + } + + if (offset < 0) + return offset; + + return vfs_setpos(file, offset, inode->i_sb->s_maxbytes); +} + +static int btrfs_file_open(struct inode *inode, struct file *filp) +{ + int ret; + + filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC | FMODE_BUF_WASYNC; + + ret = fsverity_file_open(inode, filp); + if (ret) + return ret; + return generic_file_open(inode, filp); +} + +static int check_direct_read(struct btrfs_fs_info *fs_info, + const struct iov_iter *iter, loff_t offset) +{ + int ret; + int i, seg; + + ret = check_direct_IO(fs_info, iter, offset); + if (ret < 0) + return ret; + + if (!iter_is_iovec(iter)) + return 0; + + for (seg = 0; seg < iter->nr_segs; seg++) + for (i = seg + 1; i < iter->nr_segs; i++) + if (iter->iov[seg].iov_base == iter->iov[i].iov_base) + return -EINVAL; + return 0; +} + +static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to) +{ + struct inode *inode = file_inode(iocb->ki_filp); + size_t prev_left = 0; + ssize_t read = 0; + ssize_t ret; + + if (fsverity_active(inode)) + return 0; + + if (check_direct_read(btrfs_sb(inode->i_sb), to, iocb->ki_pos)) + return 0; + + btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED); +again: + /* + * This is similar to what we do for direct IO writes, see the comment + * at btrfs_direct_write(), but we also disable page faults in addition + * to disabling them only at the iov_iter level. This is because when + * reading from a hole or prealloc extent, iomap calls iov_iter_zero(), + * which can still trigger page fault ins despite having set ->nofault + * to true of our 'to' iov_iter. + * + * The difference to direct IO writes is that we deadlock when trying + * to lock the extent range in the inode's tree during he page reads + * triggered by the fault in (while for writes it is due to waiting for + * our own ordered extent). This is because for direct IO reads, + * btrfs_dio_iomap_begin() returns with the extent range locked, which + * is only unlocked in the endio callback (end_bio_extent_readpage()). + */ + pagefault_disable(); + to->nofault = true; + ret = btrfs_dio_read(iocb, to, read); + to->nofault = false; + pagefault_enable(); + + /* No increment (+=) because iomap returns a cumulative value. */ + if (ret > 0) + read = ret; + + if (iov_iter_count(to) > 0 && (ret == -EFAULT || ret > 0)) { + const size_t left = iov_iter_count(to); + + if (left == prev_left) { + /* + * We didn't make any progress since the last attempt, + * fallback to a buffered read for the remainder of the + * range. This is just to avoid any possibility of looping + * for too long. + */ + ret = read; + } else { + /* + * We made some progress since the last retry or this is + * the first time we are retrying. Fault in as many pages + * as possible and retry. + */ + fault_in_iov_iter_writeable(to, left); + prev_left = left; + goto again; + } + } + btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED); + return ret < 0 ? ret : read; +} + +static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + ssize_t ret = 0; + + if (iocb->ki_flags & IOCB_DIRECT) { + ret = btrfs_direct_read(iocb, to); + if (ret < 0 || !iov_iter_count(to) || + iocb->ki_pos >= i_size_read(file_inode(iocb->ki_filp))) + return ret; + } + + return filemap_read(iocb, to, ret); +} + +const struct file_operations btrfs_file_operations = { + .llseek = btrfs_file_llseek, + .read_iter = btrfs_file_read_iter, + .splice_read = generic_file_splice_read, + .write_iter = btrfs_file_write_iter, + .splice_write = iter_file_splice_write, + .mmap = btrfs_file_mmap, + .open = btrfs_file_open, + .release = btrfs_release_file, + .get_unmapped_area = thp_get_unmapped_area, + .fsync = btrfs_sync_file, + .fallocate = btrfs_fallocate, + .unlocked_ioctl = btrfs_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = btrfs_compat_ioctl, +#endif + .remap_file_range = btrfs_remap_file_range, +}; + +int btrfs_fdatawrite_range(struct inode *inode, loff_t start, loff_t end) +{ + int ret; + + /* + * So with compression we will find and lock a dirty page and clear the + * first one as dirty, setup an async extent, and immediately return + * with the entire range locked but with nobody actually marked with + * writeback. So we can't just filemap_write_and_wait_range() and + * expect it to work since it will just kick off a thread to do the + * actual work. So we need to call filemap_fdatawrite_range _again_ + * since it will wait on the page lock, which won't be unlocked until + * after the pages have been marked as writeback and so we're good to go + * from there. We have to do this otherwise we'll miss the ordered + * extents and that results in badness. Please Josef, do not think you + * know better and pull this out at some point in the future, it is + * right and you are wrong. + */ + ret = filemap_fdatawrite_range(inode->i_mapping, start, end); + if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT, + &BTRFS_I(inode)->runtime_flags)) + ret = filemap_fdatawrite_range(inode->i_mapping, start, end); + + return ret; +} |