performance/io-cache: don't use stat got in read_cbk if it is zero-filled.

- translators like io-cache, read-ahead return a zero-filled stbuf in
    readv_cbk and usage of zero filled stat for cache validation is not
    correct.

Signed-off-by: Raghavendra G <raghavendra@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 376 (server-side io-cache is preventing client-side io-cache from working)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=376

2 files changed, 29 insertions, 16 deletions

diff --git a/xlators/performance/io-cache/src/io-cache.c b/xlators/performance/io-cache/src/io-cache.c
index 84b184993..59eaf4c03 100644
--- a/xlators/performance/io-cache/src/io-cache.c
+++ b/xlators/performance/io-cache/src/io-cache.c
@@ -179,18 +179,20 @@ ioc_lookup_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
 	inode_ctx_get (inode, this, &tmp_ioc_inode);
 	ioc_inode = (ioc_inode_t *)(long)tmp_ioc_inode;
 	if (ioc_inode) {
+		ioc_inode_lock (ioc_inode);
+		{
+                        if (ioc_inode->cache.mtime == 0) {
+                                ioc_inode->cache.mtime = stbuf->st_mtime;
+                        }
+		}
+		ioc_inode_unlock (ioc_inode);
+
 		cache_still_valid = ioc_cache_still_valid (ioc_inode, 
 							   stbuf);
 		
 		if (!cache_still_valid) {
 			ioc_inode_flush (ioc_inode);
 		} 
-		/* update the time-stamp of revalidation */
-		ioc_inode_lock (ioc_inode);
-		{
-			gettimeofday (&ioc_inode->cache.tv, NULL);
-		}
-		ioc_inode_unlock (ioc_inode);
 		
 		ioc_table_lock (ioc_inode->table);
 		{
@@ -468,6 +470,7 @@ ioc_open_cbk (call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
  
                                 ioc_inode = ioc_inode_update (table, inode,
                                                               weight);
+
                                 __inode_ctx_put (fd->inode, this, 
                                                  (uint64_t)(long)ioc_inode);
                         } else {
@@ -549,6 +552,12 @@ ioc_create_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
 
 			ioc_inode = ioc_inode_update (table, inode, weight);
 
+                        ioc_inode_lock (ioc_inode);
+                        {
+                                ioc_inode->cache.mtime = buf->st_mtime;
+                        }
+                        ioc_inode_unlock (ioc_inode);
+
                         inode_ctx_put (fd->inode, this,
                                        (uint64_t)(long)ioc_inode);
 		}
diff --git a/xlators/performance/io-cache/src/page.c b/xlators/performance/io-cache/src/page.c
index 4f9e76cb2..475a095e6 100644
--- a/xlators/performance/io-cache/src/page.c
+++ b/xlators/performance/io-cache/src/page.c
@@ -285,7 +285,7 @@ int8_t
 ioc_cache_still_valid (ioc_inode_t *ioc_inode, struct stat *stbuf)
 {
 	int8_t cache_still_valid = 1;
-  
+
 #if 0
 	if (!stbuf || (stbuf->st_mtime != ioc_inode->cache.mtime) || 
 	    (stbuf->st_mtim.tv_nsec != ioc_inode->stbuf.st_mtim.tv_nsec))
@@ -342,31 +342,35 @@ ioc_fault_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
 	size_t      page_size = 0;
 	ioc_waitq_t *waitq = NULL;
         size_t      iobref_page_size = 0;
+        char        zero_filled = 0;
 
         local = frame->local;
         offset = local->pending_offset;
         ioc_inode = local->inode;
         table = ioc_inode->table;
 
-	trav_offset = offset;  
+	trav_offset = offset;
 	payload_size = op_ret;
 
+        zero_filled = ((op_ret >=0)
+                       && (stbuf->st_mtime == 0));
+
 	ioc_inode_lock (ioc_inode);
 	{
-		if (op_ret == -1 || 
-		    (op_ret >= 0 && 
-		     !ioc_cache_still_valid(ioc_inode, stbuf))) {
+		if (op_ret == -1 ||
+		    !(zero_filled ||
+                      ioc_cache_still_valid(ioc_inode, stbuf))) {
 			gf_log (ioc_inode->table->xl->name, GF_LOG_TRACE,
 				"cache for inode(%p) is invalid. flushing "
 				"all pages", ioc_inode);
 			destroy_size = __ioc_inode_flush (ioc_inode);
-		} 
-    
-		if (op_ret >= 0)
+		}
+
+		if ((op_ret >= 0) && !zero_filled)
 			ioc_inode->cache.mtime = stbuf->st_mtime;
-    
+
 		gettimeofday (&ioc_inode->cache.tv, NULL);
-    
+
 		if (op_ret < 0) {
 			/* error, readv returned -1 */
 			page = ioc_page_get (ioc_inode, offset);