Files
linux/fs
Goldwyn Rodrigues ee5dd68788 btrfs: qgroup: Prevent qgroup->reserved from going subzero
commit 0b34c261e2 upstream.

While free'ing qgroup->reserved resources, we much check if
the page has not been invalidated by a truncate operation
by checking if the page is still dirty before reducing the
qgroup resources. Resources in such a case are free'd when
the entire extent is released by delayed_ref.

This fixes a double accounting while releasing resources
in case of truncating a file, reproduced by the following testcase.

SCRATCH_DEV=/dev/vdb
SCRATCH_MNT=/mnt
mkfs.btrfs -f $SCRATCH_DEV
mount -t btrfs $SCRATCH_DEV $SCRATCH_MNT
cd $SCRATCH_MNT
btrfs quota enable $SCRATCH_MNT
btrfs subvolume create a
btrfs qgroup limit 500m a $SCRATCH_MNT
sync
for c in {1..15}; do
dd if=/dev/zero  bs=1M count=40 of=$SCRATCH_MNT/a/file;
done

sleep 10
sync
sleep 5

touch $SCRATCH_MNT/a/newfile

echo "Removing file"
rm $SCRATCH_MNT/a/file

Fixes: b9d0b38928 ("btrfs: Add handler for invalidate page")
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-18 10:48:37 +01:00
..
2015-06-30 19:44:57 -07:00
2015-06-25 17:00:42 -07:00
2016-10-22 12:26:55 +02:00
2016-11-10 16:36:34 +01:00
2016-09-24 10:07:36 +02:00
2015-04-11 22:29:40 -04:00
2015-11-13 20:34:33 -05:00
2015-11-23 21:11:08 -05:00
2016-10-07 15:23:47 +02:00
2014-11-19 13:01:20 -05:00
2015-11-16 23:54:45 -08:00
2015-11-16 23:54:45 -08:00
2015-08-12 15:28:45 -05:00
2016-08-10 11:49:27 +02:00
2016-05-18 17:06:48 -07:00
2016-09-07 08:32:43 +02:00
2014-08-26 09:35:56 +02:00
2015-11-13 20:34:33 -05:00