[PATCH 6.6 262/396] xfs: dont allow overly small or large realtime volumes

Greg Kroah-Hartman
2024-04-01T16:49:12Z

commit e14293803f4e84eb23a417b462b56251033b5a66 upstream.

[backport: resolve merge conflicts due to refactoring rtbitmap/summary
macros and accessors]

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>
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/xfs/libxfs/xfs_rtbitmap.h | 13 +++++++++++++
fs/xfs/libxfs/xfs_sb.c | 3 ++-
fs/xfs/xfs_rtalloc.c | 2 ++
3 files changed, 17 insertions(+), 1 deletion(-)

--- a/fs/xfs/libxfs/xfs_rtbitmap.h
+++ b/fs/xfs/libxfs/xfs_rtbitmap.h
@@ -73,6 +73,18 @@ int xfs_rtfree_blocks(struct xfs_trans *

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;
+}
+
#else /* CONFIG_XFS_RT */
# define xfs_rtfree_extent(t,b,l) (-ENOSYS)
# define xfs_rtfree_blocks(t,rb,rl) (-ENOSYS)
@@ -81,6 +93,7 @@ uint8_t xfs_compute_rextslog(xfs_rtbxlen
# define xfs_rtbuf_get(m,t,b,i,p) (-ENOSYS)
# define xfs_rtalloc_extent_is_free(m,t,s,l,i) (-ENOSYS)
# define xfs_compute_rextslog(rtx) (0)
+# define xfs_validate_rtextents(rtx) (false)
#endif /* CONFIG_XFS_RT */

#endif /* __XFS_RTBITMAP_H__ */
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -509,7 +509,8 @@ 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,
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -998,6 +998,8 @@ xfs_growfs_rt(
*/
nrextents = nrblocks;
do_div(nrextents, in->extsize);
+ if (!xfs_validate_rtextents(nrextents))
+ return -EINVAL;
nrbmblocks = howmany_64(nrextents, NBBY * sbp->sb_blocksize);
nrextslog = xfs_compute_rextslog(nrextents);
nrsumlevels = nrextslog + 1;