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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /fs/btrfs/file.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/btrfs/file.c')
-rw-r--r--fs/btrfs/file.c3856
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;
+}