diff options
| -rw-r--r-- | fs/btrfs/qgroup.c | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index 3e6ffbbd8b0a..f8a3c1b0a15a 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -2614,6 +2614,7 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid, int ret = 0; int i; u64 *i_qgroups; + bool committing = false; struct btrfs_fs_info *fs_info = trans->fs_info; struct btrfs_root *quota_root; struct btrfs_qgroup *srcgroup; @@ -2621,7 +2622,25 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid, u32 level_size = 0; u64 nums; - mutex_lock(&fs_info->qgroup_ioctl_lock); + /* + * There are only two callers of this function. + * + * One in create_subvol() in the ioctl context, which needs to hold + * the qgroup_ioctl_lock. + * + * The other one in create_pending_snapshot() where no other qgroup + * code can modify the fs as they all need to either start a new trans + * or hold a trans handler, thus we don't need to hold + * qgroup_ioctl_lock. + * This would avoid long and complex lock chain and make lockdep happy. + */ + spin_lock(&fs_info->trans_lock); + if (trans->transaction->state == TRANS_STATE_COMMIT_DOING) + committing = true; + spin_unlock(&fs_info->trans_lock); + + if (!committing) + mutex_lock(&fs_info->qgroup_ioctl_lock); if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) goto out; @@ -2785,7 +2804,8 @@ int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid, unlock: spin_unlock(&fs_info->qgroup_lock); out: - mutex_unlock(&fs_info->qgroup_ioctl_lock); + if (!committing) + mutex_unlock(&fs_info->qgroup_ioctl_lock); return ret; } |