1 files changed, 87 insertions, 26 deletions

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index d852a2b..5372d58 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -614,7 +614,8 @@ xfs_log_mount(
 	xfs_daddr_t	blk_offset,
 	int		num_bblks)
 {
-	int		error;
+	int		error = 0;
+	int		min_logfsbs;
 
 	if (!(mp->m_flags & XFS_MOUNT_NORECOVERY))
 		xfs_notice(mp, "Mounting Filesystem");
@@ -631,6 +632,50 @@ 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.
+	 *
+	 * 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).
+	 *
+	 * We can, however, reject mounts for CRC 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;
+	}
+	if (error) {
+		if (xfs_sb_version_hascrc(&mp->m_sb)) {
+			xfs_crit(mp, "AAIEEE! Log failed size checks. Abort!");
+			ASSERT(0);
+			goto out_free_log;
+		}
+		xfs_crit(mp,
+"Log size out of supported range. Continuing onwards, but if log hangs are\n"
+"experienced then please report this message in the bug report.");
+	}
+
+	/*
 	 * Initialize the AIL now we have a log.
 	 */
 	error = xfs_trans_ail_init(mp);
@@ -720,7 +765,7 @@ xfs_log_mount_finish(xfs_mount_t *mp)
  * Unmount record used to have a string "Unmount filesystem--" in the
  * data section where the "Un" was really a magic number (XLOG_UNMOUNT_TYPE).
  * We just write the magic number now since that particular field isn't
- * currently architecture converted and "nUmount" is a bit foo.
+ * currently architecture converted and "Unmount" is a bit foo.
  * As far as I know, there weren't any dependencies on the old behaviour.
  */
 
@@ -1941,7 +1986,7 @@ xlog_print_tic_res(
 
 	xfs_alert_tag(mp, XFS_PTAG_LOGRES,
 		"xlog_write: reservation ran out. Need to up reservation");
-	xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+	xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
 }
 
 /*
@@ -2044,7 +2089,7 @@ xlog_write_setup_ophdr(
  * Set up the parameters of the region copy into the log. This has
  * to handle region write split across multiple log buffers - this
  * state is kept external to this function so that this code can
- * can be written in an obvious, self documenting manner.
+ * be written in an obvious, self documenting manner.
  */
 static int
 xlog_write_setup_copy(
@@ -3391,24 +3436,17 @@ xfs_log_ticket_get(
 }
 
 /*
- * Allocate and initialise a new log ticket.
+ * Figure out the total log space unit (in bytes) that would be
+ * required for a log ticket.
  */
-struct xlog_ticket *
-xlog_ticket_alloc(
-	struct xlog	*log,
-	int		unit_bytes,
-	int		cnt,
-	char		client,
-	bool		permanent,
-	xfs_km_flags_t	alloc_flags)
+int
+xfs_log_calc_unit_res(
+	struct xfs_mount	*mp,
+	int			unit_bytes)
 {
-	struct xlog_ticket *tic;
-	uint		num_headers;
-	int		iclog_space;
-
-	tic = kmem_zone_zalloc(xfs_log_ticket_zone, alloc_flags);
-	if (!tic)
-		return NULL;
+	struct xlog		*log = mp->m_log;
+	int			iclog_space;
+	uint			num_headers;
 
 	/*
 	 * Permanent reservations have up to 'cnt'-1 active log operations
@@ -3483,20 +3521,43 @@ xlog_ticket_alloc(
 	unit_bytes += log->l_iclog_hsize;
 
 	/* for roundoff padding for transaction data and one for commit record */
-	if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
-	    log->l_mp->m_sb.sb_logsunit > 1) {
+	if (xfs_sb_version_haslogv2(&mp->m_sb) && mp->m_sb.sb_logsunit > 1) {
 		/* log su roundoff */
-		unit_bytes += 2*log->l_mp->m_sb.sb_logsunit;
+		unit_bytes += 2 * mp->m_sb.sb_logsunit;
 	} else {
 		/* BB roundoff */
-		unit_bytes += 2*BBSIZE;
+		unit_bytes += 2 * BBSIZE;
         }
 
+	return unit_bytes;
+}
+
+/*
+ * Allocate and initialise a new log ticket.
+ */
+struct xlog_ticket *
+xlog_ticket_alloc(
+	struct xlog		*log,
+	int			unit_bytes,
+	int			cnt,
+	char			client,
+	bool			permanent,
+	xfs_km_flags_t		alloc_flags)
+{
+	struct xlog_ticket	*tic;
+	int			unit_res;
+
+	tic = kmem_zone_zalloc(xfs_log_ticket_zone, alloc_flags);
+	if (!tic)
+		return NULL;
+
+	unit_res = xfs_log_calc_unit_res(log->l_mp, unit_bytes);
+
 	atomic_set(&tic->t_ref, 1);
 	tic->t_task		= current;
 	INIT_LIST_HEAD(&tic->t_queue);
-	tic->t_unit_res		= unit_bytes;
-	tic->t_curr_res		= unit_bytes;
+	tic->t_unit_res		= unit_res;
+	tic->t_curr_res		= unit_res;
 	tic->t_cnt		= cnt;
 	tic->t_ocnt		= cnt;
 	tic->t_tid		= prandom_u32();