Re: [PATCH 3/4] vfs: count unlinked inodes

From: Christoph Hellwig
Date: Mon Nov 21 2011 - 06:34:23 EST


On Mon, Nov 21, 2011 at 12:11:32PM +0100, Miklos Szeredi wrote:
> Do not WARN_ON if set_nlink is called with zero count, just do a
> ratelimited printk. This happens on xfs and probably other
> filesystems after an unclean shutdown when the filesystem reads inodes
> which already have zero i_nlink. Reported by Christoph Hellwig.

Given that this is part of the normal recovery process printing anything
seems like a bad idea. I also don't think the code for this actually
is correct.

Remember when a filesystem recovery from unlinked but open inodes the
following happens:

- we walk the list of unlinked but open inodes, and read them into
memory, remove the linkage and then iput it.

With the current code that won't ever increment s_remove_count, but
decrement it from __destroy_inode. I suspect the right fix is to
simply not warn for a set_nlink to zero, but rather simply increment
s_remove_count for that case.

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