Patch "xfs: always swap the cow forks when swapping extents" has been added to the 4.9-stable tree

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

xfs: always swap the cow forks when swapping extents

to the 4.9-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-always-swap-the-cow-forks-when-swapping-extents.patch
and it can be found in the queue-4.9 subdirectory.

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

From: "Darrick J. Wong" <[email protected]>
Date: Mon, 18 Sep 2017 09:41:18 -0700
Subject: xfs: always swap the cow forks when swapping extents

From: Darrick J. Wong <[email protected]>

commit 52bfcdd7adbc26639bc7b2356ab9a3f5dad68ad6 upstream.

Since the CoW fork exists as a secondary data structure to the data fork, we must always swap cow forks during swapext. We also need to swap the extent counts and reset the cowblocks tags.

---
 fs/xfs/xfs_bmap_util.c |   24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

@@ -2106,11 +2106,31 @@ xfs_swap_extents(
 		ip->i_d.di_flags2 |= tip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK;
 		tip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK;
 		tip->i_d.di_flags2 |= f & XFS_DIFLAG2_REFLINK;
+	}
+
+	/* Swap the cow forks. */
+	if (xfs_sb_version_hasreflink(&mp->m_sb)) {
+		xfs_extnum_t	extnum;
+
+		ASSERT(ip->i_cformat == XFS_DINODE_FMT_EXTENTS);
+		ASSERT(tip->i_cformat == XFS_DINODE_FMT_EXTENTS);
+
+		extnum = ip->i_cnextents;
+		ip->i_cnextents = tip->i_cnextents;
+		tip->i_cnextents = extnum;
+
 		cowfp = ip->i_cowfp;
 		ip->i_cowfp = tip->i_cowfp;
 		tip->i_cowfp = cowfp;
-		xfs_inode_set_cowblocks_tag(ip);
-		xfs_inode_set_cowblocks_tag(tip);
+
+		if (ip->i_cowfp && ip->i_cnextents)
+			xfs_inode_set_cowblocks_tag(ip);
+		else
+			xfs_inode_clear_cowblocks_tag(ip);
+		if (tip->i_cowfp && tip->i_cnextents)
+			xfs_inode_set_cowblocks_tag(tip);
+		else
+			xfs_inode_clear_cowblocks_tag(tip);
 	}
 
 	xfs_trans_log_inode(tp, ip,  src_log_flags);

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

queue-4.9/xfs-don-t-unconditionally-clear-the-reflink-flag-on-zero-block-files.patch queue-4.9/xfs-cancel-dirty-pages-on-invalidation.patch queue-4.9/xfs-reinit-btree-pointer-on-attr-tree-inactivation-walk.patch queue-4.9/xfs-report-zeroed-or-not-correctly-in-xfs_zero_range.patch queue-4.9/xfs-move-more-rt-specific-code-under-config_xfs_rt.patch queue-4.9/xfs-don-t-change-inode-mode-if-acl-update-fails.patch queue-4.9/xfs-handle-error-if-xfs_btree_get_bufs-fails.patch queue-4.9/xfs-update-i_size-after-unwritten-conversion-in-dio-completion.patch queue-4.9/xfs-trim-writepage-mapping-to-within-eof.patch queue-4.9/xfs-handle-racy-aio-in-xfs_reflink_end_cow.patch queue-4.9/xfs-evict-cow-fork-extents-when-performing-finsert-fcollapse.patch queue-4.9/xfs-capture-state-of-the-right-inode-in-xfs_iflush_done.patch queue-4.9/fs-xfs-use-ps-printk-format-for-direct-addresses.patch queue-4.9/xfs-perag-initialization-should-only-touch-m_ag_max_usable-for-ag-0.patch queue-4.9/xfs-always-swap-the-cow-forks-when-swapping-extents.patch queue-4.9/xfs-don-t-log-uninitialised-fields-in-inode-structures.patch