4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Jeff Mahoney <[email protected]> commit d06f23d6a947c9abae41dc46be69a56baf36f436 upstream. We wait on qgroup rescan completion in three places: file system shutdown, the quota disable ioctl, and the rescan wait ioctl. If the user sends a signal while we're waiting, we continue happily along. This is expected behavior for the rescan wait ioctl. It's racy in the shutdown path but mostly works due to other unrelated synchronization points. In the quota disable path, it Oopses the kernel pretty much immediately. Signed-off-by: Jeff Mahoney <[email protected]> Reviewed-by: David Sterba <[email protected]> Signed-off-by: David Sterba <[email protected]> Signed-off-by: Chris Mason <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/btrfs/disk-io.c | 2 +- fs/btrfs/ioctl.c | 2 +- fs/btrfs/qgroup.c | 12 +++++++++--- fs/btrfs/qgroup.h | 3 ++- 4 files changed, 13 insertions(+), 6 deletions(-) --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3811,7 +3811,7 @@ void close_ctree(struct btrfs_root *root smp_mb(); /* wait for the qgroup rescan worker to stop */ - btrfs_qgroup_wait_for_completion(fs_info); + btrfs_qgroup_wait_for_completion(fs_info, false); /* wait for the uuid_scan task to finish */ down(&fs_info->uuid_tree_rescan_sem); --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -5121,7 +5121,7 @@ static long btrfs_ioctl_quota_rescan_wai if (!capable(CAP_SYS_ADMIN)) return -EPERM; - return btrfs_qgroup_wait_for_completion(root->fs_info); + return btrfs_qgroup_wait_for_completion(root->fs_info, true); } static long _btrfs_ioctl_set_received_subvol(struct file *file, --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -995,7 +995,7 @@ int btrfs_quota_disable(struct btrfs_tra goto out; fs_info->quota_enabled = 0; fs_info->pending_quota_state = 0; - btrfs_qgroup_wait_for_completion(fs_info); + btrfs_qgroup_wait_for_completion(fs_info, false); spin_lock(&fs_info->qgroup_lock); quota_root = fs_info->quota_root; fs_info->quota_root = NULL; @@ -2467,7 +2467,8 @@ btrfs_qgroup_rescan(struct btrfs_fs_info return 0; } -int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info) +int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info, + bool interruptible) { int running; int ret = 0; @@ -2478,9 +2479,14 @@ int btrfs_qgroup_wait_for_completion(str spin_unlock(&fs_info->qgroup_lock); mutex_unlock(&fs_info->qgroup_rescan_lock); - if (running) + if (!running) + return 0; + + if (interruptible) ret = wait_for_completion_interruptible( &fs_info->qgroup_rescan_completion); + else + wait_for_completion(&fs_info->qgroup_rescan_completion); return ret; } --- a/fs/btrfs/qgroup.h +++ b/fs/btrfs/qgroup.h @@ -46,7 +46,8 @@ int btrfs_quota_disable(struct btrfs_tra struct btrfs_fs_info *fs_info); int btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info); void btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info); -int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info); +int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info, + bool interruptible); int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, u64 src, u64 dst); int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans,
