vldb_check: fix cross-linked mh entries

When run with -fix, consolidate server numbers in vl entries which
point to the same multi-homed entry. Use the lowest server number
from the set of server numbers which point to the same multi-homed
entry.

Remove unreferenced address entries which are duplicate multi-homed
indexes.

Two passes of vldb_check -fix may be required; first to fix the
vl entry server numbers; then to remove the duplicate address
entries.

Reviewed-on: http://gerrit.openafs.org/7999
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit 911f751d1edfb18ddd5f6a699746ba14730d553d)

Change-Id: Iec977e25344ce1d5f93e3f107cc1b7ebc81d2c26
Reviewed-on: http://gerrit.openafs.org/8212
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>

diff --git a/src/vlserver/vldb_check.c b/src/vlserver/vldb_check.c
index c87c84189179de987b05f107f1801364f686cfea..64b1ca778506b0e60a301ac2b8fa5f15d691dfad 100644 (file)
--- a/src/vlserver/vldb_check.c
+++ b/src/vlserver/vldb_check.c
@@ -88,6 +88,7 @@ struct er {
 afs_int32 maxentries;
 int serveraddrs[MAXSERVERID + 2];
 u_char serverxref[MAXSERVERID + 2];  /**< to resolve cross-linked mh entries */
+int serverref[MAXSERVERID + 2];      /**< which addrs are referenced by vl entries */
 
 struct mhinfo {
     afs_uint32 addr;                   /**< vldb file record */
@@ -1198,6 +1199,47 @@ reportHashChanges(struct vlheader *header, afs_uint32 oldnamehash[HASHSIZE], afs
     }
 }
 
+/**
+ * Remove unreferenced, duplicate multi-home address indices.
+ *
+ * Removes entries from IpMappedAddr which where found to be
+ * duplicates. Only entries which are not referenced by vl entries
+ * are removed on this pass.
+ *
+ * @param[inout] header the vldb header to be updated.
+ */
+void
+removeCrossLinkedAddresses(struct vlheader *header)
+{
+    int i;
+
+    for (i = 0; i <= MAXSERVERID; i++) {
+       if (serverref[i] == 0
+           && (header->IpMappedAddr[i] & 0xff000000) == 0xff000000
+           && serverxref[i] != BADSERVERID) {
+           if (serverxref[i] == i) {
+               log_error(VLDB_CHECK_ERROR,
+                         "INTERNAL VLDB_CHECK_ERROR: serverxref points to self; index %d\n",
+                         i);
+           } else if (header->IpMappedAddr[serverxref[i]] == 0) {
+               log_error(VLDB_CHECK_ERROR,
+                         "INTERNAL VLDB_CHECK_ERROR: serverxref points to empty addr; index %d, value %d\n",
+                         i, serverxref[i]);
+           } else if (header->IpMappedAddr[serverxref[i]] != header->IpMappedAddr[i]) {
+               log_error(VLDB_CHECK_ERROR,
+                         "INTERNAL VLDB_CHECK_ERROR: invalid serverxref; index %d, value %d\n",
+                         i, serverxref[i]);
+           } else {
+               quiet_println
+                   ("FIX: Removing unreferenced address index %d, which cross-links MH block %d, index %d\n",
+                    i, (header->IpMappedAddr[i] & 0x00ff0000) >> 16,
+                    (header->IpMappedAddr[i] & 0x0000ffff));
+               header->IpMappedAddr[i] = 0;
+           }
+       }
+    }
+}
+
 int
 WorkerBee(struct cmd_syndesc *as, void *arock)
 {
@@ -1205,7 +1247,7 @@ WorkerBee(struct cmd_syndesc *as, void *arock)
     afs_int32 type;
     struct vlheader header;
     struct nvlentry vlentry, vlentry2;
-    int i, j;
+    int i, j, k;
     afs_uint32 oldnamehash[HASHSIZE];
     afs_uint32 oldidhash[MAXTYPES][HASHSIZE];
 
@@ -1247,6 +1289,7 @@ WorkerBee(struct cmd_syndesc *as, void *arock)
     memset(record, 0, (maxentries * sizeof(struct er)));
     memset(serveraddrs, 0, sizeof(serveraddrs));
     memset(mhinfo, 0, sizeof(mhinfo));
+    memset(serverref, 0, sizeof(serverref));
     for (i = 0; i <= MAXSERVERID; i++) {
        serverxref[i] = BADSERVERID;
     }
@@ -1392,11 +1435,17 @@ WorkerBee(struct cmd_syndesc *as, void *arock)
            }
 
            for (j = 0; j < NMAXNSERVERS; j++) {
-               if ((vlentry.serverNumber[j] != 255)
-                   && (serveraddrs[vlentry.serverNumber[j]] == 0)) {
-                  log_error
-                       (VLDB_CHECK_ERROR,"Volume '%s', index %d points to empty server entry %d\n",
-                        vlentry.name, j, vlentry.serverNumber[j]);
+               if (vlentry.serverNumber[j] != BADSERVERID) {
+                   serverref[vlentry.serverNumber[j]] = 1;
+                   if (serveraddrs[vlentry.serverNumber[j]] == 0) {
+                       log_error
+                           (VLDB_CHECK_ERROR,"Volume '%s', index %d points to empty server entry %d\n",
+                            vlentry.name, j, vlentry.serverNumber[j]);
+                   } else if (serverxref[vlentry.serverNumber[j]] != BADSERVERID) {
+                           log_error
+                           (VLDB_CHECK_ERROR,"Volume '%s', index %d points to server entry %d, which is cross-linked by %d\n",
+                            vlentry.name, j, vlentry.serverNumber[j], serverxref[vlentry.serverNumber[j]]);
+                   }
                }
            }
 
@@ -1517,6 +1566,36 @@ WorkerBee(struct cmd_syndesc *as, void *arock)
                        }
                    }
 
+                   /* Consolidate server numbers which point to the same mh entry.
+                    * The serverref flags are not reset here, since we want to make
+                    * sure the data is actually written before the server number is
+                    * considered unreferenced. */
+                   for (k = 0; k < NMAXNSERVERS; k++) {
+                       if (vlentry.serverNumber[k] != BADSERVERID
+                           && serverxref[vlentry.serverNumber[k]] != BADSERVERID) {
+                           u_char oldsn = vlentry.serverNumber[k];
+                           u_char newsn = serverxref[oldsn];
+                           if (newsn == oldsn) {
+                               log_error(VLDB_CHECK_ERROR,
+                                         "INTERNAL VLDB_CHECK_ERROR: serverxref points to self; index %d\n",
+                                         oldsn);
+                           } else if (header.IpMappedAddr[oldsn] == 0) {
+                               log_error(VLDB_CHECK_ERROR,
+                                         "INTERNAL VLDB_CHECK_ERROR: serverxref; points to empty address; index %d, value %d\n",
+                                         oldsn, newsn);
+                           } else if (header.IpMappedAddr[newsn] != header.IpMappedAddr[oldsn]) {
+                               log_error(VLDB_CHECK_ERROR,
+                                         "INTERNAL VLDB_CHECK_ERROR: invalid serverxref; index %d\n",
+                                         oldsn);
+                           } else {
+                               quiet_println
+                                   ("FIX: Volume '%s', index %d, server number was %d, is now %d\n",
+                                    vlentry.name, k, oldsn, newsn);
+                               vlentry.serverNumber[k] = newsn;
+                           }
+                       }
+                   }
+
                    vlentry.nextIdHash[j] = header.VolidHash[j][hash];
                    header.VolidHash[j][hash] = record[i].addr;
                }
@@ -1550,6 +1629,7 @@ WorkerBee(struct cmd_syndesc *as, void *arock)
     }
     if (fix) {
        reportHashChanges(&header, oldnamehash, oldidhash);
+       removeCrossLinkedAddresses(&header);
        writeheader(&header);
     }