On Jan 4, 2017, at 2:54 PM, Darrick J. Wong [off-list ref] wrote:

On Wed, Jan 04, 2017 at 04:29:33PM +0800, zhangyi (F) wrote:

quoted

On 2017/1/1 6:59, Valdis.Kletnieks@vt.edu said:

quoted

On Mon, 26 Dec 2016 20:34:17 +0800, yi zhang said:

quoted

Because of the disk and hardware issue, the ext4 filesystem have
many errors, the inode->i_nlink of ext4 becomes zero abnormally
but the dentry is still positive, it will cause memory corruption
after the following process:

1) Due to the inode->i_nlink is 0, this inode will be added into
the orhpan list,

quoted

+	if (WARN(inode->i_nlink == 0, "inode %lu nlink"
+		" is already 0", inode->i_ino))

Can we get the filesystem? Or at least the device major/minor? If a system
has multiple large ext4 filesystems, it would be helpful to know which
one is having the problem.

       if (WARN(inode->i_nlink == 0,
-               "inode %lu nlink is already 0", inode->i_ino))
+               "inode %lu nlink is already 0, dev=%u:%u",
+               inode->i_ino, MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev)))
               return;

We can modify as above, it's enough to know which filesystem is having the
problem, what do you think?

Why not:

if (inode->i_nlink == 0) {
	ext4_warning_inode(inode, "nlink is already 0");
	return;
}

I like this better as well.

Cheers, Andreas