[PATCH 4/4] xfs_repair: allow sysadmins to add reverse mapping indexes

Darrick J. Wong
2023-12-31T23:01:59Z

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 <djwong@kernel.org>
---
man/man8/xfs_admin.8 | 8 ++++++++
repair/globals.c | 1 +
repair/globals.h | 1 +
repair/phase2.c | 38 ++++++++++++++++++++++++++++++++++++++
repair/rmap.c | 4 ++--
repair/xfs_repair.c | 11 +++++++++++
6 files changed, 61 insertions(+), 2 deletions(-)

diff --git a/man/man8/xfs_admin.8 b/man/man8/xfs_admin.8
index 3af201cadc3..467fb2dfd0a 100644
--- a/man/man8/xfs_admin.8
+++ b/man/man8/xfs_admin.8
@@ -169,6 +169,14 @@ Enable sharing of file data blocks.
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 f0754393ba2..cff620e8f0e 100644
--- a/repair/globals.c
+++ b/repair/globals.c
@@ -54,6 +54,7 @@ bool add_bigtime; /* add support for timestamps up to 2486 */
bool add_nrext64;
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 4013d8f0d24..76d22fd3b2c 100644
--- a/repair/globals.h
+++ b/repair/globals.h
@@ -95,6 +95,7 @@ extern bool add_bigtime; /* add support for timestamps up to 2486 */
extern bool add_nrext64;
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 9a8bf411333..be0d791a8b5 100644
--- a/repair/phase2.c
+++ b/repair/phase2.c
@@ -231,6 +231,40 @@ 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)) {
+ 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;
@@ -402,6 +436,8 @@ 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;
}

@@ -481,6 +517,8 @@ 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 91a87d418e2..37fcf923644 100644
--- a/repair/rmap.c
+++ b/repair/rmap.c
@@ -53,7 +53,7 @@ rmap_needs_work(
struct xfs_mount *mp)
{
return xfs_has_reflink(mp) || add_reflink ||
- xfs_has_rmapbt(mp);
+ xfs_has_rmapbt(mp) || add_rmapbt;
}

/* Destroy an in-memory rmap btree. */
@@ -1156,7 +1156,7 @@ rmaps_verify_btree(
int have;
int error;

- if (!xfs_has_rmapbt(mp))
+ if (!xfs_has_rmapbt(mp) || add_rmapbt)
return;
if (rmapbt_suspect) {
if (no_modify && agno == 0)
diff --git a/repair/xfs_repair.c b/repair/xfs_repair.c
index d53db25e618..e94b0a79378 100644
--- a/repair/xfs_repair.c
+++ b/repair/xfs_repair.c
@@ -71,6 +71,7 @@ enum c_opt_nums {
CONVERT_NREXT64,
CONVERT_FINOBT,
CONVERT_REFLINK,
+ CONVERT_RMAPBT,
C_MAX_OPTS,
};

@@ -81,6 +82,7 @@ static char *c_opts[] = {
[CONVERT_NREXT64] = "nrext64",
[CONVERT_FINOBT] = "finobt",
[CONVERT_REFLINK] = "reflink",
+ [CONVERT_RMAPBT] = "rmapbt",
[C_MAX_OPTS] = NULL,
};

@@ -358,6 +360,15 @@ 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;