[Ocfs2-devel] [patch 09/11] ocfs2: llseek requires ocfs2 inode lock for the file in SEEK_END

[Andrew Morton]

On Thu, 6 Feb 2014 15:42:53 -0800 Mark Fasheh <mfasheh at suse.de> wrote:

> On Fri, Jan 24, 2014 at 12:47:09PM -0800, akpm at linux-foundation.org wrote:
> > From: Jensen <shencanquan at huawei.com>
> > Subject: ocfs2: llseek requires ocfs2 inode lock for the file in SEEK_END
> > 
> > llseek requires ocfs2 inode lock for updating the file size in SEEK_END. 
> > because the file size maybe update on another node.
> > 
> > This bug can be reproduce the following scenario: at first, we dd a test
> > fileA, the file size is 10k.
> 
> Basically, you want to amke SEEK_END cluster-aware. This patch would be the
> right way to do it.

Sunil was worried about the performance impact.  Correctness beats
performance, but some quantitative testing would be useful?

> Reviewed-by: Mark Fasheh <mfasheh at suse.de>

I suppose we should fix the bug it added.

--- a/fs/ocfs2/file.c~ocfs2-llseek-requires-ocfs2-inode-lock-for-the-file-in-seek_end-fix
+++ a/fs/ocfs2/file.c
@@ -2631,6 +2631,7 @@ static loff_t ocfs2_file_llseek(struct f
 		 */
 		ret = ocfs2_inode_lock(inode, NULL, 0);
 		if (ret < 0) {
+			ocfs2_inode_unlock(inode, 0);
 			mlog_errno(ret);
 			goto out;
 		}
_