[ Upstream commit 4b8d867ca6e2fc6d152f629fdaf027053b81765a ]
Emmanual Florac reports a strange occurrence when project quota limits
are enabled, free space is lower than the remaining quota, and someone
runs statvfs:
# mkfs.xfs -f /dev/sda
# mount /dev/sda /mnt -o prjquota
# xfs_quota -x -c 'limit -p bhard=2G 55' /mnt
# mkdir /mnt/dir
# xfs_io -c 'chproj 55' -c 'chattr +P' -c 'stat -vvvv' /mnt/dir
# fallocate -l 19g /mnt/a
# df /mnt /mnt/dir
Filesystem Size Used Avail Use% Mounted on
/dev/sda 20G 20G 345M 99% /mnt
/dev/sda 2.0G 0 2.0G 0% /mnt
I think the bug here is that xfs_fill_statvfs_from_dquot unconditionally
assigns to f_bfree without checking that the filesystem has enough free
space to fill the remaining project quota. However, this is a
longstanding behavior of xfs so it's unclear what to do here.
Cc: <stable@vger.kernel.org> # v2.6.18
Fixes: 932f2c3231 ("[XFS] statvfs component of directory/project quota support, code originally by Glen.")
Reported-by: Emmanuel Florac <eflorac@intellique.com>
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
4534162e09