[17/19] xfs_fsr: skip the xattr/forkoff levering with the newer swapext implementations

Commit Message

Darrick J. Wong Dec. 30, 2022, 10:18 p.m. UTC

From: Darrick J. Wong <[e-mail]>

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 <[e-mail]>
---
 fsr/xfs_fsr.c |   16 ++++++++++++++++
 1 file changed, 16 insertions(+)

Patch

diff --git a/fsr/xfs_fsr.c b/fsr/xfs_fsr.c
index bbc7d5fcabb..1fb2e5e7529 100644
--- a/fsr/xfs_fsr.c
+++ b/fsr/xfs_fsr.c
@@ -969,6 +969,22 @@  fsr_setup_attr_fork(
 	if (!(bstatp->bs_xflags & FS_XFLAG_HASATTR))
 		return 0;
 
+	/*
+	 * If the filesystem has the ability to perform atomic extent swaps or
+	 * has the reverse mapping btree enabled, 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.
+	 *
+	 * The newer bmap implementation does not require specific values of
+	 * bs_forkoff, unlike the old fork swap code.  Therefore, 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_ATOMIC_SWAP |
+			    XFS_FSOP_GEOM_FLAGS_RMAPBT))
+		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.