LU-10773 obdclass: yield cpu during changelog_block_trim_ext

To avoid soft-lockup if there are too many records to be handled.
The patch also filters out zero-sized records to avoid dead loop.

Signed-off-by: Fan Yong <fan.yong@intel.com>
Change-Id: Ia094f9153b5ef2602103d2ee13ee7ad3ffe6dc4f
Reviewed-on: https://review.whamcloud.com/31516
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>

diff --git a/lustre/obdclass/llog_osd.c b/lustre/obdclass/llog_osd.c
index 2fee9d8..f25126d 100644 (file)
--- a/lustre/obdclass/llog_osd.c
+++ b/lustre/obdclass/llog_osd.c
@@ -822,8 +822,26 @@ static void changelog_block_trim_ext(struct llog_rec_hdr *hdr,
                                extra_flags;
                }
 
                                extra_flags;
                }
 

+               if (unlikely(hdr->lrh_len == 0)) {
+                       /* It is corruption case, we cannot know the next rec,
+                        * jump to the last one directly to avoid dead loop. */
+                       LCONSOLE(D_WARNING, "Hit invalid llog record: "
+                                "idx %u, type %u, id %u\n",
+                                hdr->lrh_index, hdr->lrh_type, hdr->lrh_id);
+                       hdr = llog_rec_hdr_next(last_hdr);
+                       if (unlikely(hdr == last_hdr))
+                               LCONSOLE(D_WARNING, "The last record crashed: "
+                                        "idx %u, type %u, id %u\n",
+                                        hdr->lrh_index, hdr->lrh_type,
+                                        hdr->lrh_id);
+                       break;
+               }
+

                changelog_remap_rec(rec, rec->cr_flags & flags, xflag);
                hdr = llog_rec_hdr_next(hdr);
                changelog_remap_rec(rec, rec->cr_flags & flags, xflag);
                hdr = llog_rec_hdr_next(hdr);

+               /* Yield CPU to avoid soft-lockup if there are too many records
+                * to be handled. */
+               cond_resched();

        } while ((char *)hdr <= (char *)last_hdr);
 }
 
        } while ((char *)hdr <= (char *)last_hdr);
 }