LU-3314 scrub: use special fixed FID for .lustre

[fs/lustre-release.git] / lustre / osd-ldiskfs / osd_scrub.c

diff --git a/lustre/osd-ldiskfs/osd_scrub.c b/lustre/osd-ldiskfs/osd_scrub.c
index ec9b6c1..bf6a8b9 100644 (file)
--- a/lustre/osd-ldiskfs/osd_scrub.c
+++ b/lustre/osd-ldiskfs/osd_scrub.c
@@ -1462,7 +1462,31 @@ osd_ios_ROOT_scan(struct osd_thread_info *info, struct osd_device *dev,
                        }
                }
        } else {
-               rc = osd_ios_scan_one(info, dev, child->d_inode, NULL, 0);
+               /* For lustre-2.x (x <= 3), the ".lustre" has NO FID-in-LMA,
+                * so the client will get IGIF for the ".lustre" object when
+                * the MDT restart.
+                *
+                * From the OI scrub view, when the MDT upgrade to Lustre-2.4,
+                * it does not know whether there are some old clients cached
+                * the ".lustre" IGIF during the upgrading. Two choices:
+                *
+                * 1) Generate IGIF-in-LMA and IGIF-in-OI for the ".lustre".
+                *    It will allow the old connected clients to access the
+                *    ".lustre" with cached IGIF. But it will cause others
+                *    on the MDT failed to check "fid_is_dot_lustre()".
+                *
+                * 2) Use fixed FID {FID_SEQ_DOT_LUSTRE, FID_OID_DOT_LUSTRE, 0}
+                *    for ".lustre" in spite of whether there are some clients
+                *    cached the ".lustre" IGIF or not. It enables the check
+                *    "fid_is_dot_lustre()" on the MDT, although it will cause
+                *    that the old connected clients cannot access the ".lustre"
+                *    with the cached IGIF.
+                *
+                * Usually, it is rare case for the old connected clients
+                * to access the ".lustre" with cached IGIF. So we prefer
+                * to the solution 2). */
+               rc = osd_ios_scan_one(info, dev, child->d_inode,
+                                     &LU_DOT_LUSTRE_FID, 0);
                dput(child);
        }