salvager: Improve comments

"these used to be asserts" is not a useful comment. This area of code
does maybe look a little confusing at first glance, though, so replace
these with comments that are more informative.

Change-Id: I4e0b9dff3d010931e02559e82165ffbd61c5b189
Reviewed-on: http://gerrit.openafs.org/10313
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>

diff --git a/src/vol/vol-salvage.c b/src/vol/vol-salvage.c
index ae5e117..4d3afb5 100644 (file)
--- a/src/vol/vol-salvage.c
+++ b/src/vol/vol-salvage.c
@@ -2062,8 +2062,20 @@ DoSalvageVolumeGroup(struct SalvInfo *salvinfo, struct InodeSummary *isp, int nV
                TraceBadLinkCounts--;   /* Limit reports, per volume */
                Log("#### DEBUG #### Link count incorrect by %d; inode %s, size %llu, p=(%u,%u,%u,%u)\n", ip->linkCount, PrintInode(stmp, ip->inodeNumber), (afs_uintmax_t) ip->byteCount, ip->u.param[0], ip->u.param[1], ip->u.param[2], ip->u.param[3]); /* VolumeId in param */
            }
+
+           /* If ip->linkCount is non-zero at this point, then the linkcount
+            * for the inode on disk is wrong. Initially linkCount is set to
+            * the actual link count of the inode on disk, and then we (the
+            * salvager) decrement it for every reference to that inode that we
+            * find. So if linkCount is still positive by this point, it means
+            * that the linkcount on disk is too high, so we should DEC the
+            * inode. If linkCount is negative, it means the linkcount is too
+            * low, so we should INC the inode.
+            *
+            * If we get an error while INC'ing or DEC'ing, that's a little
+            * odd and indicates a bug, but try to continue anyway, so the
+            * volume may still be made accessible. */
            while (ip->linkCount > 0) {
-               /* below used to assert, not break */
                if (!Testing) {
                    if (IH_DEC(salvinfo->VGLinkH, ip->inodeNumber, ip->u.param[0])) {
                        Log("idec failed. inode %s errno %d\n",
@@ -2074,7 +2086,6 @@ DoSalvageVolumeGroup(struct SalvInfo *salvinfo, struct InodeSummary *isp, int nV
                ip->linkCount--;
            }
            while (ip->linkCount < 0) {
-               /* these used to be asserts */
                if (!Testing) {
                    if (IH_INC(salvinfo->VGLinkH, ip->inodeNumber, ip->u.param[0])) {
                        Log("iinc failed. inode %s errno %d\n",