vol: make namei_ListAFSSubDirs deal with multiple/bad linktables

The salvager ends up deadlocking when multiple linktables exist
in the same volume group special directory.  The issue is that we
open and flock all discovered linktables, but only close out the
last one found.  Consequently, when our child scans the linktables
again, we deadlock against the locked and leaked descriptor(s) our
parent left around before forking.

While we have so far been unable to root-cause the actual creation
of spurious linktables, this patch will at least stop the salvager
from deadlocking against itself when this occurs.

Reviewed-on: http://gerrit.openafs.org/2979
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit 19d2e0e34b5f100fdbec1da8373badd624c02248)

Change-Id: Ifd81e41258b1974b4b6e0df893fa37387bc48757
Reviewed-on: http://gerrit.openafs.org/3889
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>

diff --git a/src/vol/namei_ops.c b/src/vol/namei_ops.c
index 452213af576f9b5ed0f53b14463da5502681f17d..5045ac492779a2289271fa10a35b4cbb4c044ac3 100644 (file)
--- a/src/vol/namei_ops.c
+++ b/src/vol/namei_ops.c
@@ -1847,14 +1847,31 @@ _namei_examine_special(char * path1,
 {
     int ret = 0;
     struct ViceInodeInfo info;
+    afs_uint32 inode_vgid;
 
     if (DecodeInode(path1, dname, &info, myIH->ih_vid) < 0) {
        ret = 0;
        goto error;
     }
 
+#ifdef AFS_NT40_ENV
+    inode_vgid = myIH->ih_vid;
+#else
+    inode_vgid = (info.inodeNumber >> NAMEI_UNIQSHIFT) & NAMEI_UNIQMASK;
+#endif
+
     if (info.u.param[2] != VI_LINKTABLE) {
        info.linkCount = 1;
+    } else if ((info.u.param[0] != myIH->ih_vid) ||
+              (inode_vgid != myIH->ih_vid)) {
+       /* VGID encoded in linktable filename and/or OGM data isn't
+        * consistent with VGID encoded in namei path */
+       Log("namei_ListAFSSubDirs: warning: inconsistent linktable "
+           "filename \"%s/%s\"; salvager will delete it "
+           "(dir_vgid=%u, inode_vgid=%u, ogm_vgid=%u)\n",
+           path1, dname, myIH->ih_vid,
+           (unsigned int)inode_vgid,
+           info.u.param[0]);
     } else {
        char path2[512];
        /* Open this handle */
@@ -2415,6 +2432,11 @@ namei_ListAFSSubDirs(IHandle_t * dirIH,
     ninodes += code;
 #endif
 
+    if (linkHandle.fd_fd == INVALID_FD) {
+       Log("namei_ListAFSSubDirs: warning: VG %u does not have a link table; "
+           "salvager will recreate it.\n", dirIH->ih_vid);
+    }
+
     /* Now run through all the other subdirs */
     namei_HandleToVolDir(&name, &myIH);
     strlcpy(path1, name.n_path, sizeof(path1));