[Ocfs2-devel] [PATCH] ocfs2: mknod: fix recursive locking hung

[Gang He]

Hi Junxiao,

The problem looks easy to reproduce?
Could you share the trigger script/code for this issue?


Thanks
Gang


>>> 
> Here another recursive lock caught and it caused the cluster hung.
> 
>  #0 [ffff88008e3935a8] __schedule at ffffffff816e4722
>  #1 [ffff88008e393600] schedule at ffffffff816e4dee
>  #2 [ffff88008e393620] schedule_timeout at ffffffff816e7cd5
>  #3 [ffff88008e3936c0] wait_for_completion at ffffffff816e631f
>  #4 [ffff88008e393740] __ocfs2_cluster_lock at ffffffffa05a9111 [ocfs2]
>  #5 [ffff88008e393890] ocfs2_inode_lock_full_nested at ffffffffa05aec14 
> [ocfs2]
>  #6 [ffff88008e393910] ocfs2_inode_lock_tracker at ffffffffa05af02f [ocfs2]
>  #7 [ffff88008e393970] ocfs2_iop_get_acl at ffffffffa0620c92 [ocfs2]
>  #8 [ffff88008e3939d0] get_acl at ffffffff8126ae79
>  #9 [ffff88008e3939f0] posix_acl_create at ffffffff8126b27a
>  #10 [ffff88008e393a20] ocfs2_mknod at ffffffffa05cedcc [ocfs2]
>  #11 [ffff88008e393b60] ocfs2_create at ffffffffa05cfb13 [ocfs2]
>  #12 [ffff88008e393bd0] vfs_create at ffffffff81217338
>  #13 [ffff88008e393c10] lookup_open at ffffffff81217a85
>  #14 [ffff88008e393ca0] do_last at ffffffff8121ac6d
>  #15 [ffff88008e393d30] path_openat at ffffffff8121b112
>  #16 [ffff88008e393df0] do_filp_open at ffffffff8121b53a
>  #17 [ffff88008e393ed0] do_sys_open at ffffffff81209a5a
>  #18 [ffff88008e393f40] sys_open at ffffffff81209bae
>  #19 [ffff88008e393f50] system_call_fastpath at ffffffff816e902e
> 
> inode lock is got by ocfs2_mknod() before call into posix_acl_create().
> 
> Signed-off-by: Junxiao Bi <junxiao.bi at oracle.com>
> Cc: <stable at vger.kernel.org>
> ---
>  fs/ocfs2/namei.c |   14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
> index 3b0a10d9b36f..f0ee52e600ff 100644
> --- a/fs/ocfs2/namei.c
> +++ b/fs/ocfs2/namei.c
> @@ -260,6 +260,8 @@ static int ocfs2_mknod(struct inode *dir,
>  	sigset_t oldset;
>  	int did_block_signals = 0;
>  	struct ocfs2_dentry_lock *dl = NULL;
> +	int locked;
> +	struct ocfs2_lock_holder oh;
>  
>  	trace_ocfs2_mknod(dir, dentry, dentry->d_name.len, dentry->d_name.name,
>  			  (unsigned long long)OCFS2_I(dir)->ip_blkno,
> @@ -274,11 +276,11 @@ static int ocfs2_mknod(struct inode *dir,
>  	/* get our super block */
>  	osb = OCFS2_SB(dir->i_sb);
>  
> -	status = ocfs2_inode_lock(dir, &parent_fe_bh, 1);
> -	if (status < 0) {
> -		if (status != -ENOENT)
> -			mlog_errno(status);
> -		return status;
> +	locked = ocfs2_inode_lock_tracker(dir, &parent_fe_bh, 1, &oh);
> +	if (locked < 0) {
> +		if (locked != -ENOENT)
> +			mlog_errno(locked);
> +		return locked;
>  	}
>  
>  	if (S_ISDIR(mode) && (dir->i_nlink >= ocfs2_link_max(osb))) {
> @@ -462,7 +464,7 @@ static int ocfs2_mknod(struct inode *dir,
>  	if (handle)
>  		ocfs2_commit_trans(osb, handle);
>  
> -	ocfs2_inode_unlock(dir, 1);
> +	ocfs2_inode_unlock_tracker(dir, 1, &oh, locked);
>  	if (did_block_signals)
>  		ocfs2_unblock_signals(&oldset);
>  
> -- 
> 1.7.9.5
> 
> 
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