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authorJustin Maggard <jmaggard10@gmail.com>2015-11-06 19:36:42 +0100
committerChris Mason <clm@fb.com>2015-11-25 14:22:08 +0100
commit967ef5131e42d6e3bb216c44161d893048a49957 (patch)
tree245253c420e34541f82ef76d46f2b89226ab025b /fs/btrfs/qgroup.c
parentBtrfs: fix race between cleaner kthread and space cache writeout (diff)
downloadlinux-967ef5131e42d6e3bb216c44161d893048a49957.tar.xz
linux-967ef5131e42d6e3bb216c44161d893048a49957.zip
btrfs: qgroup: fix quota disable during rescan
There's a race condition that leads to a NULL pointer dereference if you disable quotas while a quota rescan is running. To fix this, we just need to wait for the quota rescan worker to actually exit before tearing down the quota structures. Signed-off-by: Justin Maggard <jmaggard@netgear.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to '')
-rw-r--r--fs/btrfs/qgroup.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 93e12c18ffd7..fd0a196c8f74 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -993,9 +993,10 @@ int btrfs_quota_disable(struct btrfs_trans_handle *trans,
mutex_lock(&fs_info->qgroup_ioctl_lock);
if (!fs_info->quota_root)
goto out;
- spin_lock(&fs_info->qgroup_lock);
fs_info->quota_enabled = 0;
fs_info->pending_quota_state = 0;
+ btrfs_qgroup_wait_for_completion(fs_info);
+ spin_lock(&fs_info->qgroup_lock);
quota_root = fs_info->quota_root;
fs_info->quota_root = NULL;
fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;