[PATCH 2/4] xfs: validate the realtime geometry in xfs_validate_sb_common

Darrick J. Wong
2020-03-25T03:24:47Z

From: Darrick J. Wong <darrick.wong@oracle.com>

Validate the geometry of the realtime geometry when we mount the
filesystem, so that we don't abruptly shut down the filesystem later on.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_sb.c | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)

diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index 2f60fc3c99a0..dee0a1a594dc 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -328,6 +328,41 @@ xfs_validate_sb_common(
return -EFSCORRUPTED;
}

+ /* Validate the realtime geometry; stolen from xfs_repair */
+ if (unlikely(
+ sbp->sb_rextsize * sbp->sb_blocksize > XFS_MAX_RTEXTSIZE ||
+ sbp->sb_rextsize * sbp->sb_blocksize < XFS_MIN_RTEXTSIZE)) {
+ xfs_notice(mp,
+ "realtime extent sanity check failed");
+ return -EFSCORRUPTED;
+ }
+
+ if (sbp->sb_rblocks == 0) {
+ if (unlikely(
+ sbp->sb_rextents != 0 ||
+ sbp->sb_rbmblocks != 0 ||
+ sbp->sb_rextslog != 0 ||
+ sbp->sb_frextents != 0)) {
+ xfs_notice(mp,
+ "realtime zeroed geometry sanity check failed");
+ return -EFSCORRUPTED;
+ }
+ } else {
+ xfs_rtblock_t rexts;
+ uint32_t temp;
+
+ rexts = div_u64_rem(sbp->sb_rblocks, sbp->sb_rextsize, &temp);
+ if (unlikely(
+ rexts != sbp->sb_rextents ||
+ sbp->sb_rextslog != xfs_highbit32(sbp->sb_rextents) ||
+ sbp->sb_rbmblocks != howmany(sbp->sb_rextents,
+ NBBY * sbp->sb_blocksize))) {
+ xfs_notice(mp,
+ "realtime geometry sanity check failed");
+ return -EFSCORRUPTED;
+ }
+ }
+
if (sbp->sb_unit) {
if (!xfs_sb_version_hasdalign(sbp) ||
sbp->sb_unit > sbp->sb_width ||