[PATCH 13/67] xfs: don't allow overly small or large realtime volumes

Darrick J. Wong
2024-03-13T01:56:26Z

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

Source kernel commit: e14293803f4e84eb23a417b462b56251033b5a66

Don't allow realtime volumes that are less than one rt extent long.
This has been broken across 4 LTS kernels with nobody noticing, so let's
just disable it.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
libxfs/xfs_rtbitmap.h | 13 +++++++++++++
libxfs/xfs_sb.c | 3 ++-
mkfs/xfs_mkfs.c | 5 +++++
repair/sb.c | 3 +++
4 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/libxfs/xfs_rtbitmap.h b/libxfs/xfs_rtbitmap.h
index 6e5bae324cc3..1c84b52de3d4 100644
--- a/libxfs/xfs_rtbitmap.h
+++ b/libxfs/xfs_rtbitmap.h
@@ -353,6 +353,18 @@ int xfs_rtfree_blocks(struct xfs_trans *tp, xfs_fsblock_t rtbno,

uint8_t xfs_compute_rextslog(xfs_rtbxlen_t rtextents);

+/* Do we support an rt volume having this number of rtextents? */
+static inline bool
+xfs_validate_rtextents(
+ xfs_rtbxlen_t rtextents)
+{
+ /* No runt rt volumes */
+ if (rtextents == 0)
+ return false;
+
+ return true;
+}
+
xfs_filblks_t xfs_rtbitmap_blockcount(struct xfs_mount *mp, xfs_rtbxlen_t
rtextents);
unsigned long long xfs_rtbitmap_wordcount(struct xfs_mount *mp,
@@ -372,6 +384,7 @@ unsigned long long xfs_rtsummary_wordcount(struct xfs_mount *mp,
# define xfs_rtbuf_cache_relse(a) (0)
# define xfs_rtalloc_extent_is_free(m,t,s,l,i) (-ENOSYS)
# define xfs_compute_rextslog(rtx) (0)
+# define xfs_validate_rtextents(rtx) (false)
static inline xfs_filblks_t
xfs_rtbitmap_blockcount(struct xfs_mount *mp, xfs_rtbxlen_t rtextents)
{
diff --git a/libxfs/xfs_sb.c b/libxfs/xfs_sb.c
index 95a29bf1ffcf..7a72d5a17910 100644
--- a/libxfs/xfs_sb.c
+++ b/libxfs/xfs_sb.c
@@ -507,7 +507,8 @@ xfs_validate_sb_common(
rbmblocks = howmany_64(sbp->sb_rextents,
NBBY * sbp->sb_blocksize);

- if (sbp->sb_rextents != rexts ||
+ if (!xfs_validate_rtextents(rexts) ||
+ sbp->sb_rextents != rexts ||
sbp->sb_rextslog != xfs_compute_rextslog(rexts) ||
sbp->sb_rbmblocks != rbmblocks) {
xfs_notice(mp,
diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index abea61943652..1a0a71dbec78 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -3025,6 +3025,11 @@ reported by the device (%u).\n"),
}

cfg->rtextents = cfg->rtblocks / cfg->rtextblocks;
+ if (cfg->rtextents == 0) {
+ fprintf(stderr,
+_("cannot have an rt subvolume with zero extents\n"));
+ usage();
+ }
cfg->rtbmblocks = (xfs_extlen_t)howmany(cfg->rtextents,
NBBY * cfg->blocksize);
}
diff --git a/repair/sb.c b/repair/sb.c
index 384840db1cec..faf79d9d0835 100644
--- a/repair/sb.c
+++ b/repair/sb.c
@@ -475,6 +475,9 @@ verify_sb(char *sb_buf, xfs_sb_t *sb, int is_primary_sb)
if (sb->sb_rblocks / sb->sb_rextsize != sb->sb_rextents)
return(XR_BAD_RT_GEO_DATA);

+ if (sb->sb_rextents == 0)
+ return XR_BAD_RT_GEO_DATA;
+
if (sb->sb_rextslog != libxfs_compute_rextslog(sb->sb_rextents))
return(XR_BAD_RT_GEO_DATA);