commit ce0dcee626c482183b42d45b6ea43198c7223fc7
author Goldwyn Rodrigues <rgoldwyn@suse.com> Tue Mar 14 05:25:09 2017 -0500
committer David Sterba <dsterba@suse.com> Wed Mar 29 14:29:08 2017 +0200
tree c3f9bf304edd911f25f5c26f73039f3e471afed2
parent 9d0d1c8b1c9d80b17cfa86ecd50c8933a742585c

btrfs: Change qgroup_meta_rsv to 64bit

Using an int value is causing qg->reserved to become negative and
exclusive -EDQUOT to be reached prematurely.

This affects exclusive qgroups only.

TEST CASE:

DEVICE=/dev/vdb
MOUNTPOINT=/mnt
SUBVOL=$MOUNTPOINT/tmp

umount $SUBVOL
umount $MOUNTPOINT

mkfs.btrfs -f $DEVICE
mount /dev/vdb $MOUNTPOINT
btrfs quota enable $MOUNTPOINT
btrfs subvol create $SUBVOL
umount $MOUNTPOINT
mount /dev/vdb $MOUNTPOINT
mount -o subvol=tmp $DEVICE $SUBVOL
btrfs qgroup limit -e 3G $SUBVOL

btrfs quota rescan /mnt -w

for i in `seq 1 44000`; do
  dd if=/dev/zero of=/mnt/tmp/test_$i bs=10k count=1
  if [[ $? > 0 ]]; then
     btrfs qgroup show -pcref $SUBVOL
     exit 1
  fi
done

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
[ add reproducer to changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 73fdc6b..982c56f 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1342,7 +1342,7 @@ static void __setup_root(struct btrfs_root *root, struct btrfs_fs_info *fs_info,
 	atomic_set(&root->orphan_inodes, 0);
 	atomic_set(&root->refs, 1);
 	atomic_set(&root->will_be_snapshoted, 0);
-	atomic_set(&root->qgroup_meta_rsv, 0);
+	atomic64_set(&root->qgroup_meta_rsv, 0);
 	root->log_transid = 0;
 	root->log_transid_committed = -1;
 	root->last_log_commit = 0;