[LU-6465] OSD ID mapping cache is not safe to use.

Thu, 12 May 2016 17:55:08 +0000

t seems osd_id_map is not safe to use right now. So the pair of [FID, OID] is added to cache after lookup, but if another thread delete the object, it will only invalidate the cache in its own thread info.

int osd_oi_delete(struct osd_thread_info *info,
                  struct osd_device *osd, const struct lu_fid *fid,
                  handle_t *th, enum oi_check_flags flags)
{
        struct lu_fid *oi_fid = &info->oti_fid2;

        /* clear idmap cache */
        if (lu_fid_eq(fid, &info->oti_cache.oic_fid))
                fid_zero(&info->oti_cache.oic_fid);
      ..............

And other threads can still get the OID from the cache, and if the inode has been reused by other object, then we will see bunch of

Lustre: lustre-MDT0003-osd: FID [0x2c0000404:0x1f34:0x0] != self_fid [0x2c0000404:0x281c:0x0]

Unfortunately, it will also trigger osd-scrub in this case, this is what I saw in the DNE2 failover test.

Whamcloud Community JIRA

[LU-6465] OSD ID mapping cache is not safe to use.