diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index 66e8353da2f3..24038c1cc943 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -310,7 +310,6 @@ xfs_validate_sb_common(
 	    sbp->sb_inodelog < XFS_DINODE_MIN_LOG			||
 	    sbp->sb_inodelog > XFS_DINODE_MAX_LOG			||
 	    sbp->sb_inodesize != (1 << sbp->sb_inodelog)		||
-	    sbp->sb_logsunit > XLOG_MAX_RECORD_BSIZE			||
 	    sbp->sb_inopblock != howmany(sbp->sb_blocksize,sbp->sb_inodesize) ||
 	    XFS_FSB_TO_B(mp, sbp->sb_agblocks) < XFS_MIN_AG_BYTES	||
 	    XFS_FSB_TO_B(mp, sbp->sb_agblocks) > XFS_MAX_AG_BYTES	||
@@ -328,6 +327,61 @@ xfs_validate_sb_common(
 		return -EFSCORRUPTED;
 	}
 
+	/*
+	 * Logs that are too large are not supported at all. Reject them
+	 * outright. Logs that are too small are tolerated on v4 filesystems,
+	 * but we can only check that when mounting the log. Hence we skip
+	 * those checks here.
+	 */
+	if (sbp->sb_logblocks > XFS_MAX_LOG_BLOCKS) {
+		xfs_notice(mp,
+		"Log size 0x%x blocks too large, maximum size is 0x%llx blocks",
+			 sbp->sb_logblocks, XFS_MAX_LOG_BLOCKS);
+		return -EFSCORRUPTED;
+	}
+
+	if (XFS_FSB_TO_B(mp, sbp->sb_logblocks) > XFS_MAX_LOG_BYTES) {
+		xfs_warn(mp,
+		"log size 0x%llx bytes too large, maximum size is 0x%llx bytes",
+			 XFS_FSB_TO_B(mp, sbp->sb_logblocks),
+			 XFS_MAX_LOG_BYTES);
+		return -EFSCORRUPTED;
+	}
+
+	/*
+	 * Do not allow filesystems with corrupted log sector or stripe units to
+	 * be mounted. We cannot safely size the iclogs or write to the log if
+	 * the log stripe unit is not valid.
+	 */
+	if (sbp->sb_versionnum & XFS_SB_VERSION_SECTORBIT) {
+		if (sbp->sb_logsectsize != (1U << sbp->sb_logsectlog)) {
+			xfs_notice(mp,
+			"log sector size in bytes/log2 (0x%x/0x%x) must match",
+				sbp->sb_logsectsize, 1U << sbp->sb_logsectlog);
+			return -EFSCORRUPTED;
+		}
+	} else if (sbp->sb_logsectsize || sbp->sb_logsectlog) {
+		xfs_notice(mp,
+		"log sector size in bytes/log2 (0x%x/0x%x) are not zero",
+			sbp->sb_logsectsize, sbp->sb_logsectlog);
+		return -EFSCORRUPTED;
+	}
+
+	if (sbp->sb_logsunit > 1) {
+		if (sbp->sb_logsunit % sbp->sb_blocksize) {
+			xfs_notice(mp,
+		"log stripe unit 0x%x bytes must be a multiple of block size",
+				sbp->sb_logsunit);
+			return -EFSCORRUPTED;
+		}
+		if (sbp->sb_logsunit > XLOG_MAX_RECORD_BSIZE) {
+			xfs_notice(mp,
+		"log stripe unit 0x%x bytes over maximum size (0x%x bytes)",
+				sbp->sb_logsunit, XLOG_MAX_RECORD_BSIZE);
+			return -EFSCORRUPTED;
+		}
+	}
+
 	/* Validate the realtime geometry; stolen from xfs_repair */
 	if (sbp->sb_rextsize * sbp->sb_blocksize > XFS_MAX_RTEXTSIZE ||
 	    sbp->sb_rextsize * sbp->sb_blocksize < XFS_MIN_RTEXTSIZE) {
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 22d7d74231d4..c731378704f0 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -562,7 +562,6 @@ 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;
 
@@ -583,53 +582,37 @@ xfs_log_mount(
 	}
 
 	/*
-	 * Validate the given log space and drop a critical message via syslog
-	 * if the log size is too small that would lead to some unexpected
-	 * situations in transaction log space reservation stage.
+	 * Now that we have set up the log and it's internal geometry
+	 * parameters, we can validate the given log space and drop a critical
+	 * message via syslog if the log size is too small. A log that is too
+	 * small can lead to unexpected situations in transaction log space
+	 * reservation stage. The superblock verifier has already validated all
+	 * the other log geometry constraints, so we don't have to check those
+	 * here.
 	 *
-	 * Note: we can't just reject the mount if the validation fails.  This
-	 * would mean that people would have to downgrade their kernel just to
-	 * remedy the situation as there is no way to grow the log (short of
-	 * black magic surgery with xfs_db).
+	 * Note: For v4 filesystems, we can't just reject the mount if the
+	 * validation fails.  This would mean that people would have to
+	 * downgrade their kernel just to remedy the situation as there is no
+	 * way to grow the log (short of black magic surgery with xfs_db).
 	 *
-	 * We can, however, reject mounts for CRC format filesystems, as the
+	 * We can, however, reject mounts for V5 format filesystems, as the
 	 * mkfs binary being used to make the filesystem should never create a
 	 * filesystem with a log that is too small.
 	 */
 	min_logfsbs = xfs_log_calc_minimum_size(mp);
-
 	if (mp->m_sb.sb_logblocks < min_logfsbs) {
 		xfs_warn(mp,
 		"Log size %d blocks too small, minimum size is %d blocks",
 			 mp->m_sb.sb_logblocks, min_logfsbs);
-		error = -EINVAL;
-	} else if (mp->m_sb.sb_logblocks > XFS_MAX_LOG_BLOCKS) {
-		xfs_warn(mp,
-		"Log size %d blocks too large, maximum size is %lld blocks",
-			 mp->m_sb.sb_logblocks, XFS_MAX_LOG_BLOCKS);
-		error = -EINVAL;
-	} else if (XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks) > XFS_MAX_LOG_BYTES) {
-		xfs_warn(mp,
-		"log size %lld bytes too large, maximum size is %lld bytes",
-			 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) {
+
 		/*
 		 * Log check errors are always fatal on v5; or whenever bad
 		 * metadata leads to a crash.
 		 */
-		if (fatal) {
+		if (xfs_sb_version_hascrc(&mp->m_sb)) {
 			xfs_crit(mp, "AAIEEE! Log failed size checks. Abort!");
 			ASSERT(0);
+			error = -EINVAL;
 			goto out_free_log;
 		}
 		xfs_crit(mp, "Log size out of supported range.");
