[03/10] xfs_repair: allow sysadmins to add reverse mapping indexes

Commit Message

Darrick J. Wong Dec. 31, 2024, 11:53 p.m. UTC

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

Allow the sysadmin to use xfs_repair to upgrade an existing filesystem
to support the reverse mapping btree index.  This is needed for online
fsck.

Signed-off-by: "Darrick J. Wong" <[e-mail]>
---
 man/man8/xfs_admin.8 |    8 ++++++++
 repair/globals.c     |    1 +
 repair/globals.h     |    1 +
 repair/phase2.c      |   38 ++++++++++++++++++++++++++++++++++++++
 repair/rmap.c        |    6 +++---
 repair/xfs_repair.c  |   11 +++++++++++
 6 files changed, 62 insertions(+), 3 deletions(-)

Patch

diff --git a/man/man8/xfs_admin.8 b/man/man8/xfs_admin.8
index 3a9175c9f018e5..74a400dcfeb557 100644
--- a/man/man8/xfs_admin.8
+++ b/man/man8/xfs_admin.8
@@ -176,6 +176,14 @@  .SH OPTIONS
 This upgrade can fail if any AG has less than 2% free space remaining.
 The filesystem cannot be downgraded after this feature is enabled.
 This feature was added to Linux 4.9.
+.TP 0.4i
+.B rmapbt
+Store an index of the owners of on-disk blocks.
+This enables much stronger cross-referencing of various metadata structures
+and online repairs to space usage metadata.
+The filesystem cannot be downgraded after this feature is enabled.
+This upgrade can fail if any AG has less than 5% free space remaining.
+This feature was added to Linux 4.8.
 .RE
 .TP
 .BI \-U " uuid"
diff --git a/repair/globals.c b/repair/globals.c
index cf4421e34dec84..dd7c422bb922e4 100644
--- a/repair/globals.c
+++ b/repair/globals.c
@@ -55,6 +55,7 @@  bool	add_nrext64;
 bool	add_exchrange;		/* add file content exchange support */
 bool	add_finobt;		/* add free inode btrees */
 bool	add_reflink;		/* add reference count btrees */
+bool	add_rmapbt;		/* add reverse mapping btrees */
 
 /* misc status variables */
 
diff --git a/repair/globals.h b/repair/globals.h
index efbb8db79bc080..d8c2aae23d8f0a 100644
--- a/repair/globals.h
+++ b/repair/globals.h
@@ -96,6 +96,7 @@  extern bool	add_nrext64;
 extern bool	add_exchrange;		/* add file content exchange support */
 extern bool	add_finobt;		/* add free inode btrees */
 extern bool	add_reflink;		/* add reference count btrees */
+extern bool	add_rmapbt;		/* add reverse mapping btrees */
 
 /* misc status variables */
 
diff --git a/repair/phase2.c b/repair/phase2.c
index 9cd841f8d05fc6..9dd37e7fc5c111 100644
--- a/repair/phase2.c
+++ b/repair/phase2.c
@@ -261,6 +261,40 @@  set_reflink(
 	return true;
 }
 
+static bool
+set_rmapbt(
+	struct xfs_mount	*mp,
+	struct xfs_sb		*new_sb)
+{
+	if (xfs_has_rmapbt(mp)) {
+		printf(_("Filesystem already supports reverse mapping btrees.\n"));
+		exit(0);
+	}
+
+	if (!xfs_has_crc(mp)) {
+		printf(
+	_("Reverse mapping btree feature only supported on V5 filesystems.\n"));
+		exit(0);
+	}
+
+	if (xfs_has_realtime(mp)) {
+		printf(
+	_("Reverse mapping btree feature not supported with realtime.\n"));
+		exit(0);
+	}
+
+	if (xfs_has_reflink(mp) && !add_reflink) {
+		printf(
+	_("Reverse mapping btrees cannot be added when reflink is enabled.\n"));
+		exit(0);
+	}
+
+	printf(_("Adding reverse mapping btrees to filesystem.\n"));
+	new_sb->sb_features_ro_compat |= XFS_SB_FEAT_RO_COMPAT_RMAPBT;
+	new_sb->sb_features_incompat |= XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR;
+	return true;
+}
+
 struct check_state {
 	struct xfs_sb		sb;
 	uint64_t		features;
@@ -431,6 +465,8 @@  need_check_fs_free_space(
 		return true;
 	if (xfs_has_reflink(mp) && !(old->features & XFS_FEAT_REFLINK))
 		return true;
+	if (xfs_has_rmapbt(mp) && !(old->features & XFS_FEAT_RMAPBT))
+		return true;
 	return false;
 }
 
@@ -512,6 +548,8 @@  upgrade_filesystem(
 		dirty |= set_finobt(mp, &new_sb);
 	if (add_reflink)
 		dirty |= set_reflink(mp, &new_sb);
+	if (add_rmapbt)
+		dirty |= set_rmapbt(mp, &new_sb);
 	if (!dirty)
 		return;
 
diff --git a/repair/rmap.c b/repair/rmap.c
index 91f864351f6013..f1f837d33ea4f4 100644
--- a/repair/rmap.c
+++ b/repair/rmap.c
@@ -69,7 +69,7 @@  rmap_needs_work(
 	struct xfs_mount	*mp)
 {
 	return xfs_has_reflink(mp) || add_reflink ||
-	       xfs_has_rmapbt(mp);
+	       xfs_has_rmapbt(mp) || add_rmapbt;
 }
 
 static inline bool rmaps_has_observations(const struct xfs_ag_rmap *ag_rmap)
@@ -1339,7 +1339,7 @@  rmaps_verify_btree(
 	struct xfs_perag	*pag = NULL;
 	int			error;
 
-	if (!xfs_has_rmapbt(mp))
+	if (!xfs_has_rmapbt(mp) || add_rmapbt)
 		return;
 	if (rmapbt_suspect) {
 		if (no_modify && agno == 0)
@@ -1398,7 +1398,7 @@  rtrmaps_verify_btree(
 	struct xfs_inode	*ip = NULL;
 	int			error;
 
-	if (!xfs_has_rmapbt(mp))
+	if (!xfs_has_rmapbt(mp) || add_rmapbt)
 		return;
 	if (rmapbt_suspect) {
 		if (no_modify && rgno == 0)
diff --git a/repair/xfs_repair.c b/repair/xfs_repair.c
index e436dc2ef736d6..ca72c65f9d772a 100644
--- a/repair/xfs_repair.c
+++ b/repair/xfs_repair.c
@@ -73,6 +73,7 @@  enum c_opt_nums {
 	CONVERT_EXCHRANGE,
 	CONVERT_FINOBT,
 	CONVERT_REFLINK,
+	CONVERT_RMAPBT,
 	C_MAX_OPTS,
 };
 
@@ -84,6 +85,7 @@  static char *c_opts[] = {
 	[CONVERT_EXCHRANGE]	= "exchange",
 	[CONVERT_FINOBT]	= "finobt",
 	[CONVERT_REFLINK]	= "reflink",
+	[CONVERT_RMAPBT]	= "rmapbt",
 	[C_MAX_OPTS]		= NULL,
 };
 
@@ -394,6 +396,15 @@  process_args(int argc, char **argv)
 		_("-c reflink only supports upgrades\n"));
 					add_reflink = true;
 					break;
+				case CONVERT_RMAPBT:
+					if (!val)
+						do_abort(
+		_("-c rmapbt requires a parameter\n"));
+					if (strtol(val, NULL, 0) != 1)
+						do_abort(
+		_("-c rmapbt only supports upgrades\n"));
+					add_rmapbt = true;
+					break;
 				default:
 					unknown('c', val);
 					break;