xfs: validate sb_logsunit is a multiple of the fs blocksize

Make sure the log stripe unit is sane before proceeding with mounting.
AFAICT this means that logsunit has to be 0, 1, or a multiple of the fs
block size.  Found this by setting the LSB of logsunit in xfs/350 and
watching the system crash as soon as we try to write to the log.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index ab59e78a5d87abdd54d1f0a139bdc18608f6d497..0c4c9ad3be701f833600cbdb875b3129fc685dd7 100644 (file)
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -608,6 +608,7 @@ xfs_log_mount(
        xfs_daddr_t     blk_offset,
        int             num_bblks)
 {
+       bool            fatal = xfs_sb_version_hascrc(&mp->m_sb);
        int             error = 0;
        int             min_logfsbs;
 
@@ -659,9 +660,20 @@ xfs_log_mount(
                         XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks),
                         XFS_MAX_LOG_BYTES);
                error = -EINVAL;
+       } else if (mp->m_sb.sb_logsunit > 1 &&
+                  mp->m_sb.sb_logsunit % mp->m_sb.sb_blocksize) {
+               xfs_warn(mp,
+               "log stripe unit %u bytes must be a multiple of block size",
+                        mp->m_sb.sb_logsunit);
+               error = -EINVAL;
+               fatal = true;
        }
        if (error) {
-               if (xfs_sb_version_hascrc(&mp->m_sb)) {
+               /*
+                * Log check errors are always fatal on v5; or whenever bad
+                * metadata leads to a crash.
+                */
+               if (fatal) {
                        xfs_crit(mp, "AAIEEE! Log failed size checks. Abort!");
                        ASSERT(0);
                        goto out_free_log;