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btrfs: lock the inode first before flushing range when punching hole

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When doing hole punching we are flushing delalloc and waiting for ordered
extents to complete before locking the inode (VFS lock and the btrfs
specific i_mmap_lock). This is fine because even if a write happens after
we call btrfs_wait_ordered_range() and before we lock the inode (call
btrfs_inode_lock()), we will notice the write at
btrfs_punch_hole_lock_range() and flush delalloc and wait for its ordered
extent.

We can however make this simpler by locking first the inode an then call
btrfs_wait_ordered_range(), which will allow us to remove the ordered
extent lookup logic from btrfs_punch_hole_lock_range() in the next patch.
It also makes the behaviour the same as plain fallocate, hole punching
and reflinks.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Filipe Manana 2022-03-15 15:22:39 +00:00 committed by David Sterba
parent ffa8fc603d
commit bd6526d0df
1 changed files with 3 additions and 2 deletions
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5
fs/btrfs/file.c
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@ -2976,11 +2976,12 @@ static int btrfs_punch_hole(struct file *file, loff_t offset, loff_t len)
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)
return ret;
goto out_only_mutex;
btrfs_inode_lock(inode, BTRFS_ILOCK_MMAP);
ino_size = round_up(inode->i_size, fs_info->sectorsize);
ret = find_first_non_hole(BTRFS_I(inode), &offset, &len);
if (ret < 0)