Add a proper subclass to get rid of the following lockdep error. [ INFO: possible recursive locking detected ] 4.9.0+ #279 Not tainted --------------------------------------------- vim/4801 is trying to acquire lock: (&ei->log_mutex){+.+...}, at: [<000003ff82057592>] btrfs_log_inode+0x182/0xfa8 [btrfs]
(&ei->log_mutex){+.+...}, at: [<000003ff82057592>] btrfs_log_inode+0x182/0xfa8 [btrfs] Possible unsafe locking scenario: CPU0 ---- lock(&ei->log_mutex); lock(&ei->log_mutex); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by vim/4801: #0: (&sb->s_type->i_mutex_key#15){+.+.+.}, at: [<000003ff81fc274c>] btrfs_sync_file+0x204/0x728 [btrfs] #1: (sb_internal#2){.+.+..}, at: [<000003ff81fa38e0>] start_transaction+0x318/0x770 [btrfs] #2: (&ei->log_mutex){+.+...}, at: [<000003ff82057592>] [...] Call Trace: ([<0000000000115ffc>] show_trace+0xe4/0x108) [<00000000001160f8>] show_stack+0x68/0xe0 [<0000000000652d52>] dump_stack+0x9a/0xd8 [<0000000000209bb0>] __lock_acquire+0xac8/0x1bd0 [<000000000020b3c6>] lock_acquire+0x106/0x4a0 [<0000000000a1fb36>] mutex_lock_nested+0xa6/0x428 [<000003ff82057592>] btrfs_log_inode+0x182/0xfa8 [btrfs] [<000003ff82057c76>] btrfs_log_inode+0x866/0xfa8 [btrfs] [<000003ff81ffe278>] btrfs_log_inode_parent+0x218/0x988 [btrfs] [<000003ff81ffffaa>] btrfs_log_dentry_safe+0x7a/0xa0 [btrfs] [<000003ff81fc29b6>] btrfs_sync_file+0x46e/0x728 [btrfs] [<000000000044aeee>] do_fsync+0x5e/0x90 [<000000000044b2ba>] SyS_fsync+0x32/0x40 [<0000000000a26786>] system_call+0xd6/0x288 Signed-off-by: Christian Borntraeger <borntrae...@de.ibm.com> --- fs/btrfs/tree-log.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 3d33c4e..a3ec717 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -4648,7 +4648,7 @@ static int btrfs_log_inode(struct btrfs_trans_handle *trans, return ret; } - mutex_lock(&BTRFS_I(inode)->log_mutex); + mutex_lock_nested(&BTRFS_I(inode)->log_mutex, inode_only); /* * a brute force approach to making sure we get the most uptodate -- 2.7.4