On Thu, Feb 1, 2018 at 2:27 AM, Amir Goldstein amir73il@gmail.com wrote:

On Mon, Jan 29, 2018 at 5:50 PM, Darrick J. Wong darrick.wong@oracle.com wrote:

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On Mon, Jan 29, 2018 at 01:07:36PM +0200, Amir Goldstein wrote:

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On Fri, Jan 26, 2018 at 11:44 PM, Darrick J. Wong darrick.wong@oracle.com wrote:

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On Fri, Jan 26, 2018 at 09:44:29AM +0200, Amir Goldstein wrote:

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Commit 66f364649d870 ("xfs: remove if_rdev") moved storing of rdev value for special inodes to VFS inodes, but forgot to preserve the value of i_rdev when recycling a reclaimable xfs_inode.

This was detected by xfstest overlay/017 with inodex=on mount option and xfs base fs. The test does a lookup of overlay chardev and blockdev right after drop caches.

Overlayfs inodes hold a reference on underlying xfs inodes when mount option index=on is configured. If drop caches reclaim xfs inodes, before it relclaims overlayfs inodes, that can sometimes leave a reclaimable xfs inode and that test hits that case quite often.

When that happens, the xfs inode cache remains broken (zere i_rdev) until the next cycle mount or drop caches.

Fixes: 66f364649d870 ("xfs: remove if_rdev") Signed-off-by: Amir Goldstein amir73il@gmail.com

Looks ok, Reviewed-by: Darrick J. Wong darrick.wong@oracle.com

I recon that now we should now also strap: Cc: stable@vger.kernel.org #v4.15

Can I assume, you'll add it on apply?

I'll do a proper backport of this and a couple other critical cow fixes after I get the 4.16 stuff merged.

I am not sure what "proper backport" means in the context of this patch. This is a v4.15-rc1 regression fix that is based on v4.15-rc8. It applied cleanly on v4.15.

CC'ing stable for attention.

This patch is now in master, but due to its timing it did not get the CC: stable tag.

Now really CC stable.

Amir.