From: Darrick J. Wong <djwong@kernel.org>
Date: Mon, 29 Jul 2024 23:23:00 +0000 (-0700)
Subject: xfs_fsr: skip the xattr/forkoff levering with the newer swapext implementations
X-Git-Tag: v6.10.0~23^2~4
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=63ea34b8f00c4b86115b770fdab487e9157d712b;p=thirdparty%2Fxfsprogs-dev.git

xfs_fsr: skip the xattr/forkoff levering with the newer swapext implementations

The newer swapext implementations in the kernel run at a high enough
level (above the bmap layer) that it's no longer required to manipulate
bs_forkoff by creating garbage xattrs to get the extent tree that we
want.  If we detect the newer algorithms, skip this error prone step.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---

diff --git a/fsr/xfs_fsr.c b/fsr/xfs_fsr.c
index c6dbfb22..22e134ad 100644
--- a/fsr/xfs_fsr.c
+++ b/fsr/xfs_fsr.c
@@ -999,6 +999,20 @@ fsr_setup_attr_fork(
 	if (!(bstatp->bs_xflags & FS_XFLAG_HASATTR))
 		return 0;
 
+	/*
+	 * If the filesystem has the ability to perform atomic file mapping
+	 * exchanges, the file extent swap implementation uses a higher level
+	 * algorithm that calls into the bmap code instead of playing games
+	 * with swapping the extent forks.
+	 *
+	 * This new functionality does not require specific values of
+	 * bs_forkoff, unlike the old fork swap code.  Leave the extended
+	 * attributes alone if we know we're not using the old fork swap
+	 * strategy.  This eliminates a major source of runtime errors in fsr.
+	 */
+	if (fsgeom.flags & XFS_FSOP_GEOM_FLAGS_EXCHANGE_RANGE)
+		return 0;
+
 	/*
 	 * use the old method if we have attr1 or the kernel does not yet
 	 * support passing the fork offset in the bulkstat data.