btrfs: Return EAGAIN if we can't start no snpashot write in check_can_nocow

The first thing code does in check_can_nocow is trying to block
concurrent snapshots. If this fails (due to snpashot already being in
progress) the function returns ENOSPC which makes no sense. Instead
return EAGAIN. Despite this return value not being propagated to callers
it's good practice to return the closest in terms of semantics error
code. No functional changes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Nikolay Borisov 2019-05-07 10:23:46 +03:00 committed by David Sterba
parent 0b6f5d408b
commit 5f791ec31f

View file

@ -1556,7 +1556,7 @@ static noinline int check_can_nocow(struct btrfs_inode *inode, loff_t pos,
ret = btrfs_start_write_no_snapshotting(root);
if (!ret)
return -ENOSPC;
return -EAGAIN;
lockstart = round_down(pos, fs_info->sectorsize);
lockend = round_up(pos + *write_bytes,