[RFC][PATCH] xfs: preserve i_rdev when recycling a reclaimable inode

[Amir Goldstein <amir73il@gmail.com>]

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---

Darrick,

This patch fixes a problem I am hitting consistenty with xfstest
overlay/017 with certain overlay mount options (index=on,nfs_export=off).

I see that overlayfs looks up in underlying xfs and gets a chardev
or blockdev inode with non initialized i_rdev (these are not whiteout
inodes).

It takes a certain timing which happens in this test that does lookup
immediately after drop caches. The test causes a permanent error in
inode cache of xfs that is only fixed after another drop caches or
cycle mount.

So I am certain there is a problem and that this patch fixes the
problem, I'm just not sure this is the right fix and if it is, which
is the commit that it "Fixes".

Thanks,
Amir.

 fs/xfs/xfs_icache.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 3861d61fb265..3ce946063ffe 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -295,6 +295,7 @@ xfs_reinit_inode(
 	uint32_t	generation = inode->i_generation;
 	uint64_t	version = inode->i_version;
 	umode_t		mode = inode->i_mode;
+	dev_t		dev = inode->i_rdev;
 
 	error = inode_init_always(mp->m_super, inode);
 
@@ -302,6 +303,7 @@ xfs_reinit_inode(
 	inode->i_generation = generation;
 	inode->i_version = version;
 	inode->i_mode = mode;
+	inode->i_rdev = dev;
 	return error;
 }
 
-- 
2.7.4