[24/27] xfs_repair: reserve per-AG space while rebuilding rt metadata

Commit Message

Darrick J. Wong Feb. 6, 2025, 10:55 p.m. UTC

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

Realtime metadata btrees can consume quite a bit of space on a full
filesystem.  Since the metadata are just regular files, we need to
make the per-AG reservations to avoid overfilling any of the AGs while
rebuilding metadata.  This avoids the situation where a filesystem comes
straight from repair and immediately trips over not having enough space
in an AG.

Signed-off-by: "Darrick J. Wong" <[e-mail]>
---
 include/libxfs.h |    1 +
 repair/phase6.c  |   45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

Comments

Christoph Hellwig Feb. 7, 2025, 5:57 a.m. UTC | #1

On Thu, Feb 06, 2025 at 02:55:59PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <[e-mail]>
> 
> Realtime metadata btrees can consume quite a bit of space on a full
> filesystem.  Since the metadata are just regular files, we need to

I think there is an inodes or btrees missing after metadata above.

Otherwise looks good:

Reviewed-by: Christoph Hellwig <[e-mail]>

Patch

diff --git a/include/libxfs.h b/include/libxfs.h
index 79f8e1ff03d3f5..82b34b9d81c3a7 100644
--- a/include/libxfs.h
+++ b/include/libxfs.h
@@ -101,6 +101,7 @@  struct iomap;
 #include "xfs_rtgroup.h"
 #include "xfs_rtbitmap.h"
 #include "xfs_rtrmap_btree.h"
+#include "xfs_ag_resv.h"
 
 #ifndef ARRAY_SIZE
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
diff --git a/repair/phase6.c b/repair/phase6.c
index 2ddfd0526767e0..30ea19fda9fd87 100644
--- a/repair/phase6.c
+++ b/repair/phase6.c
@@ -3540,10 +3540,41 @@  reset_quota_metadir_inodes(
 	libxfs_irele(dp);
 }
 
+static int
+reserve_ag_blocks(
+	struct xfs_mount	*mp)
+{
+	struct xfs_perag	*pag = NULL;
+	int			error = 0;
+	int			err2;
+
+	mp->m_finobt_nores = false;
+
+	while ((pag = xfs_perag_next(mp, pag))) {
+		err2 = -libxfs_ag_resv_init(pag, NULL);
+		if (err2 && !error)
+			error = err2;
+	}
+
+	return error;
+}
+
+static void
+unreserve_ag_blocks(
+	struct xfs_mount	*mp)
+{
+	struct xfs_perag	*pag = NULL;
+
+	while ((pag = xfs_perag_next(mp, pag)))
+		libxfs_ag_resv_free(pag);
+}
+
 void
 phase6(xfs_mount_t *mp)
 {
 	ino_tree_node_t		*irec;
+	bool			reserve_perag;
+	int			error;
 	int			i;
 
 	parent_ptr_init(mp);
@@ -3588,6 +3619,17 @@  phase6(xfs_mount_t *mp)
 		do_warn(_("would reinitialize metadata root directory\n"));
 	}
 
+	reserve_perag = xfs_has_realtime(mp) && !no_modify;
+	if (reserve_perag) {
+		error = reserve_ag_blocks(mp);
+		if (error) {
+			if (error != ENOSPC)
+				do_warn(
+	_("could not reserve per-AG space to rebuild realtime metadata"));
+			reserve_perag = false;
+		}
+	}
+
 	if (xfs_has_rtgroups(mp))
 		reset_rt_metadir_inodes(mp);
 	else
@@ -3596,6 +3638,9 @@  phase6(xfs_mount_t *mp)
 	if (xfs_has_metadir(mp) && xfs_has_quota(mp) && !no_modify)
 		reset_quota_metadir_inodes(mp);
 
+	if (reserve_perag)
+		unreserve_ag_blocks(mp);
+
 	mark_standalone_inodes(mp);
 
 	do_log(_("        - traversing filesystem ...\n"));