[08/10] xfs_repair: allow sysadmins to add realtime reflink

Commit Message

Darrick J. Wong Dec. 31, 2024, 11:55 p.m. UTC

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

Allow the sysadmin to use xfs_repair to upgrade an existing filesystem
to support the realtime reference count btree, and therefore reflink on
realtime volumes.

Signed-off-by: "Darrick J. Wong" <[e-mail]>
---
 repair/phase2.c |   53 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 50 insertions(+), 3 deletions(-)

Patch

diff --git a/repair/phase2.c b/repair/phase2.c
index b1288bf3dd90cd..8dc936b572196e 100644
--- a/repair/phase2.c
+++ b/repair/phase2.c
@@ -250,14 +250,15 @@  set_reflink(
 		exit(0);
 	}
 
-	if (xfs_has_realtime(mp)) {
-		printf(_("Reflink feature not supported with realtime.\n"));
+	if (xfs_has_realtime(mp) && !xfs_has_rtgroups(mp)) {
+		printf(_("Reference count btree requires realtime groups.\n"));
 		exit(0);
 	}
 
 	printf(_("Adding reflink support to filesystem.\n"));
 	new_sb->sb_features_ro_compat |= XFS_SB_FEAT_RO_COMPAT_REFLINK;
 	new_sb->sb_features_incompat |= XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR;
+
 	return true;
 }
 
@@ -497,6 +498,38 @@  reserve_rtrmap_inode(
 	return -libxfs_metafile_resv_init(ip, ask);
 }
 
+/*
+ * Reserve space to handle rt refcount btree expansion.
+ *
+ * If the refcount inode for this group already exists, we assume that we're
+ * adding some other feature.  Note that we have not validated the metadata
+ * directory tree, so we must perform the lookup by hand and abort the upgrade
+ * if there are errors.  If the inode does not exist, the amount of space
+ * needed to handle a new maximally sized refcount btree is added to @new_resv.
+ */
+static int
+reserve_rtrefcount_inode(
+	struct xfs_rtgroup	*rtg,
+	xfs_rfsblock_t		*new_resv)
+{
+	struct xfs_mount	*mp = rtg_mount(rtg);
+	struct xfs_inode	*ip = rtg_refcount(rtg);
+	xfs_filblks_t		ask;
+
+	if (!xfs_has_rtreflink(mp))
+		return 0;
+
+	ask = libxfs_rtrefcountbt_calc_reserves(mp);
+
+	/* failed to load the rtdir inode? */
+	if (!ip) {
+		*new_resv += ask;
+		return 0;
+	}
+
+	return -libxfs_metafile_resv_init(ip, ask);
+}
+
 static void
 check_fs_free_space(
 	struct xfs_mount		*mp,
@@ -594,6 +627,18 @@  _("Not enough free space would remain for rtgroup %u rmap inode.\n"),
 			do_error(
 _("Error %d while checking rtgroup %u rmap inode space reservation.\n"),
 					error, rtg_rgno(rtg));
+
+		error = reserve_rtrefcount_inode(rtg, &new_resv);
+		if (error == ENOSPC) {
+			printf(
+_("Not enough free space would remain for rtgroup %u refcount inode.\n"),
+					rtg_rgno(rtg));
+			exit(0);
+		}
+		if (error)
+			do_error(
+_("Error %d while checking rtgroup %u refcount inode space reservation.\n"),
+					error, rtg_rgno(rtg));
 	}
 
 	/*
@@ -621,8 +666,10 @@  _("Error %d while checking rtgroup %u rmap inode space reservation.\n"),
 	}
 
 	/* Unreserve the realtime metadata reservations. */
-	while ((rtg = xfs_rtgroup_next(mp, rtg)))
+	while ((rtg = xfs_rtgroup_next(mp, rtg))) {
 		libxfs_metafile_resv_free(rtg_rmap(rtg));
+		libxfs_metafile_resv_free(rtg_refcount(rtg));
+	}
 
 	/*
 	 * Release the per-AG reservations and mark the per-AG structure as