Patch "xfs: preserve i_rdev when recycling a reclaimable inode" has been added to the 4.15-stable tree

This is a note to let you know that I've just added the patch titled

xfs: preserve i_rdev when recycling a reclaimable inode

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
xfs-preserve-i_rdev-when-recycling-a-reclaimable-inode.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Amir Goldstein <[email protected]>
Date: Fri, 26 Jan 2018 11:24:40 -0800
Subject: xfs: preserve i_rdev when recycling a reclaimable inode

From: Amir Goldstein <[email protected]>

commit acd1d71598f7654b6d7718bcbe979992295c672a upstream.

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.

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

@@ -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;
 }
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/xfs-preserve-i_rdev-when-recycling-a-reclaimable-inode.patch