feature/geo-rep: Keep marker.tstamp's mtime unchangeable during snapshot.

Problem:

Geo-replicatoin does a full xsync crawl after snapshot
restoration of slave and master. It does not do history crawl.

Analysis:

Marker creates 'marker.tstamp' file when geo-rep is started
for the first time. The virtual extended attribute
'trusted.glusterfs.volume-mark' is maintained and whenever
it is queried on gluster mount point, marker fills it on
the fly and returns the combination of uuid, ctime of
marker.tstamp and others. So ctime of marker.tstamp, in other
sense 'volume-mark'  marks the geo-rep start time when the
session is freshly created.

From the above, after the first filesystem crawl(xsync) is
done during first geo-rep start, stime should always be less
than 'volume-mark'. So whenever stime is less than volume-mark,
it does full filesystem crawl (xsync).

Root Cause:

When snapshot is restored, marker.tstamp file is freshly
created losing the timestamps, it was originally created with.

Solution:

1. Change is made to depend on mtime instead of ctime.
2. mtime and atime of marker.tstamp is restored back when
   snapshot is created and restored.

Change-Id: I4891b112f4aedc50cfae402832c50c5145807d7a
BUG: 1125918
Signed-off-by: Kotresh H R <khiremat@redhat.com>
Reviewed-on: http://review.gluster.org/8401
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

2 files changed, 44 insertions, 0 deletions

diff --git a/libglusterfs/src/common-utils.c b/libglusterfs/src/common-utils.c
index 54ee3e53818..be8bd6298ac 100644
--- a/libglusterfs/src/common-utils.c
+++ b/libglusterfs/src/common-utils.c
@@ -3232,3 +3232,46 @@ gf_compare_sockaddr (const struct sockaddr *addr1,
         }
         return _gf_false;
 }
+
+/*
+ * gf_set_timestamp:
+ *      It sets the mtime and atime of 'dest' file as of 'src'.
+ */
+
+int
+gf_set_timestamp  (const char *src, const char* dest)
+{
+        struct stat    sb             = {0, };
+        struct timeval new_time[2]    = {{0, },{0,}};
+        int            ret            = 0;
+        xlator_t       *this          = NULL;
+
+        this = THIS;
+        GF_ASSERT (this);
+        GF_ASSERT (src);
+        GF_ASSERT (dest);
+
+        ret = stat (src, &sb);
+        if (ret) {
+                gf_log (this->name, GF_LOG_ERROR, "stat on %s failed: %s",
+                        src, strerror(errno));
+                goto out;
+        }
+        new_time[0].tv_sec = sb.st_atime;
+        new_time[0].tv_usec = ST_ATIM_NSEC (&sb)/1000;
+
+        new_time[1].tv_sec = sb.st_mtime;
+        new_time[1].tv_usec = ST_MTIM_NSEC (&sb)/1000;
+
+        /* The granularity is micro seconds as per the current
+         * requiremnt. Hence using 'utimes'. This can be updated
+         * to 'utimensat' if we need timestamp in nanoseconds.
+         */
+        ret = utimes (dest, new_time);
+        if (ret) {
+                gf_log (this->name, GF_LOG_ERROR, "utimes on %s failed: %s",
+                        dest, strerror(errno));
+        }
+out:
+        return ret;
+}
diff --git a/libglusterfs/src/common-utils.h b/libglusterfs/src/common-utils.h
index 98f30fc47b0..4eec5170c60 100644
--- a/libglusterfs/src/common-utils.h
+++ b/libglusterfs/src/common-utils.h
@@ -620,6 +620,7 @@ int gf_get_hostname_from_ip (char *client_ip, char **hostname);
 gf_boolean_t gf_is_local_addr (char *hostname);
 gf_boolean_t gf_is_same_address (char *host1, char *host2);
 void md5_wrapper(const unsigned char *data, size_t len, char *md5);
+int gf_set_timestamp  (const char *src, const char* dest);
 
 int gf_thread_create (pthread_t *thread, const pthread_attr_t *attr,
                       void *(*start_routine)(void *), void *arg);