*tail_blk = BLOCK_LSN(be64_to_cpu(rhead->h_tail_lsn));
/*
- * Trim the head block back to skip over torn records. We can have
- * multiple log I/Os in flight at any time, so we assume CRC failures
- * back through the previous several records are torn writes and skip
- * them.
- */
- error = xlog_verify_head(log, head_blk, tail_blk, bp, &rhead_blk,
- &rhead, &wrapped);
- if (error)
- goto done;
-
- /*
* Set the log state based on the current head record.
*/
xlog_set_state(log, *head_blk, rhead, rhead_blk, wrapped);
goto done;
/*
+ * Verify the log head if the log is not clean (e.g., we have anything
+ * but an unmount record at the head). This uses CRC verification to
+ * detect and trim torn writes. If discovered, CRC failures are
+ * considered torn writes and the log head is trimmed accordingly.
+ *
+ * Note that we can only run CRC verification when the log is dirty
+ * because there's no guarantee that the log data behind an unmount
+ * record is compatible with the current architecture.
+ */
+ if (!clean) {
+ xfs_daddr_t orig_head = *head_blk;
+
+ error = xlog_verify_head(log, head_blk, tail_blk, bp,
+ &rhead_blk, &rhead, &wrapped);
+ if (error)
+ goto done;
+
+ /* update in-core state again if the head changed */
+ if (*head_blk != orig_head) {
+ xlog_set_state(log, *head_blk, rhead, rhead_blk,
+ wrapped);
+ tail_lsn = atomic64_read(&log->l_tail_lsn);
+ error = xlog_check_unmount_rec(log, head_blk, tail_blk,
+ rhead, rhead_blk, bp,
+ &clean);
+ if (error)
+ goto done;
+ }
+ }
+
+ /*
* Note that the unmount was clean. If the unmount was not clean, we
* need to know this to rebuild the superblock counters from the perag
* headers if we have a filesystem using non-persistent counters.