[PATCH 2/2] xfs: allow userspace to rebuild metadata structures

From: "Darrick J. Wong" <djwong@kernel.org>
To: djwong@kernel.org
Cc: Dave Chinner <dchinner@redhat.com>, linux-xfs@vger.kernel.org
Subject: [PATCH 2/2] xfs: allow userspace to rebuild metadata structures
Date: Thu, 27 Jul 2023 15:29:45 -0700	[thread overview]
Message-ID: <169049625048.922058.11628715914998137912.stgit@frogsfrogsfrogs> (raw)
In-Reply-To: <169049625018.922058.9081185927358791336.stgit@frogsfrogsfrogs>

From: Darrick J. Wong <djwong@kernel.org>

Add a new (superuser-only) flag to the online metadata repair ioctl to
force it to rebuild structures, even if they're not broken.  We will use
this to move metadata structures out of the way during a free space
defragmentation operation.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_fs.h |    6 +++++-
 fs/xfs/scrub/scrub.c   |   11 ++++++++++-
 fs/xfs/scrub/trace.h   |    3 ++-
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index 2cbf9ea39b8cc..6360073865dbc 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -743,7 +743,11 @@ struct xfs_scrub_metadata {
  */
 #define XFS_SCRUB_OFLAG_NO_REPAIR_NEEDED (1u << 7)
 
-#define XFS_SCRUB_FLAGS_IN	(XFS_SCRUB_IFLAG_REPAIR)
+/* i: Rebuild the data structure. */
+#define XFS_SCRUB_IFLAG_FORCE_REBUILD	(1u << 8)
+
+#define XFS_SCRUB_FLAGS_IN	(XFS_SCRUB_IFLAG_REPAIR | \
+				 XFS_SCRUB_IFLAG_FORCE_REBUILD)
 #define XFS_SCRUB_FLAGS_OUT	(XFS_SCRUB_OFLAG_CORRUPT | \
 				 XFS_SCRUB_OFLAG_PREEN | \
 				 XFS_SCRUB_OFLAG_XFAIL | \
diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index a2492aae34d4f..b62a5e59dee42 100644
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -411,6 +411,11 @@ xchk_validate_inputs(
 		goto out;
 	}
 
+	/* No rebuild without repair. */
+	if ((sm->sm_flags & XFS_SCRUB_IFLAG_FORCE_REBUILD) &&
+	    !(sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR))
+		return -EINVAL;
+
 	/*
 	 * We only want to repair read-write v5+ filesystems.  Defer the check
 	 * for ops->repair until after our scrub confirms that we need to
@@ -539,8 +544,12 @@ xfs_scrub_metadata(
 	    !(sc->flags & XREP_ALREADY_FIXED)) {
 		bool needs_fix = xchk_needs_repair(sc->sm);
 
+		/* Userspace asked us to rebuild the structure regardless. */
+		if (sc->sm->sm_flags & XFS_SCRUB_IFLAG_FORCE_REBUILD)
+			needs_fix = true;
+
 		/* Let debug users force us into the repair routines. */
-		if (XFS_TEST_ERROR(false, mp, XFS_ERRTAG_FORCE_SCRUB_REPAIR))
+		if (XFS_TEST_ERROR(needs_fix, mp, XFS_ERRTAG_FORCE_SCRUB_REPAIR))
 			needs_fix = true;
 
 		/*
diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h
index 83ed6e01c7df6..4dd807230308e 100644
--- a/fs/xfs/scrub/trace.h
+++ b/fs/xfs/scrub/trace.h
@@ -98,7 +98,8 @@ TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_FSCOUNTERS);
 	{ XFS_SCRUB_OFLAG_XCORRUPT,		"xcorrupt" }, \
 	{ XFS_SCRUB_OFLAG_INCOMPLETE,		"incomplete" }, \
 	{ XFS_SCRUB_OFLAG_WARNING,		"warning" }, \
-	{ XFS_SCRUB_OFLAG_NO_REPAIR_NEEDED,	"norepair" }
+	{ XFS_SCRUB_OFLAG_NO_REPAIR_NEEDED,	"norepair" }, \
+	{ XFS_SCRUB_IFLAG_FORCE_REBUILD,	"rebuild" }
 
 #define XFS_SCRUB_STATE_STRINGS \
 	{ XCHK_TRY_HARDER,			"try_harder" }, \

