Re: [PATCH] xfs: Fix WARN_ON(delalloc) in xfs_vm_releasepage()

Jan Kara
2013-03-18T16:06:02Z

[-- Attachment #1: Type: text/plain, Size: 1141 bytes --]

On Fri 15-03-13 15:52:14, Ben Myers wrote:
> Hi Jan,
>
> On Thu, Mar 14, 2013 at 02:30:54PM +0100, Jan Kara wrote:
> > When a dirty page is truncated from a file but reclaim gets to it before
> > truncate_inode_pages(), we hit WARN_ON(delalloc) in
> > xfs_vm_releasepage(). This is because reclaim tries to write the page,
> > xfs_vm_writepage() just bails out (leaving page clean) and thus reclaim
> > thinks it can continue and calls xfs_vm_releasepage() on page with dirty
> > buffers.
> >
> > Fix the issue by redirtying the page in xfs_vm_writepage(). This makes
> > reclaim stop reclaiming the page and also logically it keeps page in a
> > more consistent state where page with dirty buffers has PageDirty set.
>
> Was there an easy way to reproduce this? I'm testing and reviewing this now
> and it might help.
I used scripts/run-bash-shared-mapping.sh from the attached tarball - it
fires up several processes beating a file with mmap accesses while
truncating the file and memory stressing the machine. I presume fsx with
some memhog could trigger the issue as well.

Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR

[-- Attachment #2: ext3-tools.tar.gz --]
[-- Type: application/x-compressed-tar, Size: 96501 bytes --]

[-- Attachment #3: Type: text/plain, Size: 121 bytes --]