On Tue, Jun 9, 2020 at 10:32 PM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > > On Tue, Jun 09, 2020 at 10:28:06PM +0800, Yafang Shao wrote: > > On Tue, Jun 9, 2020 at 10:03 PM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > > > > > > On Thu, Jun 04, 2020 at 03:05:47AM -0400, Yafang Shao wrote: > > > > Recently there is a XFS deadlock on our server with an old kernel. > > > > This deadlock is caused by allocating memory in xfs_map_blocks() while > > > > doing writeback on behalf of memroy reclaim. Although this deadlock happens > > > > on an old kernel, I think it could happen on the upstream as well. This > > > > issue only happens once and can't be reproduced, so I haven't tried to > > > > reproduce it on upsteam kernel. > > > > > > The report looks sensible, but I don't think the iomap code is the > > > right place for this. Until/unless the VM people agree that > > > ->writepages(s) generally should not recurse into the fs I think the > > > low-level file system allocating is the right place, so xfs_map_blocks > > > would seem like the correct place. > > > > Thanks for your comment. > > That is what I did in the previous version [1]. > > So should I resend the v1 ? > > Well, v1 won't apply. But I do prefer the approach there. All right. Let's include MM maintainers and see the opinion from them. Hi Michal, Andrew, What's your opinion on this XFS deadlock ? Should ->writepages(s) generally not recurse into the fs ? -- Thanks Yafang
