ext4: rename and improbe ext4_es_find_extent()

This commit renames ext4_es_find_extent with ext4_es_find_delayed_extent
and improve this function. First, we split input and output parameter.
Second, this function never return the first block of the next delayed
extent after 'es'.

Signed-off-by: Zheng Liu <[e-mail]>
Signed-off-by: "Theodore Ts'o" <[e-mail]>
Cc: Jan kara <[e-mail]>

fs/ext4/extents.c

···
 {
 	struct extent_status es;
 
-	es.es_lblk = lblk_start;
-	(void)ext4_es_find_extent(inode, &es);
+	ext4_es_find_delayed_extent(inode, lblk_start, &es);
 	if (es.es_len == 0)
 		return 0; /* there is no delay extent in this tree */
 	else if (es.es_lblk <= lblk_start &&
···
 				    struct ext4_ext_cache *newex)
 {
 	struct extent_status es;
-	ext4_lblk_t next_del;
+	ext4_lblk_t block, next_del;
 
-	es.es_lblk = newex->ec_block;
-	next_del = ext4_es_find_extent(inode, &es);
+	ext4_es_find_delayed_extent(inode, newex->ec_block, &es);
 
 	if (newex->ec_start == 0) {
 		/*
···
 
 		newex->ec_len = es.es_lblk + es.es_len - newex->ec_block;
 	}
+
+	block = newex->ec_block + newex->ec_len;
+	ext4_es_find_delayed_extent(inode, block, &es);
+	if (es.es_len == 0)
+		next_del = EXT_MAX_BLOCKS;
+	else
+		next_del = es.es_lblk;
 
 	return next_del;
 }

fs/ext4/extents_status.c

···
 }
 
 /*
- * ext4_es_find_extent: find the 1st delayed extent covering @es->lblk
+ * ext4_es_find_delayed_extent: find the 1st delayed extent covering @es->lblk
  * if it exists, otherwise, the next extent after @es->lblk.
  *
  * @inode: the inode which owns delayed extents
+ * @lblk: the offset where we start to search
  * @es: delayed extent that we found
- *
- * Returns the first block of the next extent after es, otherwise
- * EXT_MAX_BLOCKS if no extent is found.
- * Delayed extent is returned via @es.
  */
-ext4_lblk_t ext4_es_find_extent(struct inode *inode, struct extent_status *es)
+void ext4_es_find_delayed_extent(struct inode *inode, ext4_lblk_t lblk,
+				 struct extent_status *es)
 {
 	struct ext4_es_tree *tree = NULL;
 	struct extent_status *es1 = NULL;
 	struct rb_node *node;
-	ext4_lblk_t ret = EXT_MAX_BLOCKS;
 
-	trace_ext4_es_find_extent_enter(inode, es->es_lblk);
+	BUG_ON(es == NULL);
+	trace_ext4_es_find_delayed_extent_enter(inode, lblk);
 
 	read_lock(&EXT4_I(inode)->i_es_lock);
 	tree = &EXT4_I(inode)->i_es_tree;
 
 	/* find extent in cache firstly */
-	es->es_len = es->es_pblk = 0;
+	es->es_lblk = es->es_len = es->es_pblk = 0;
 	if (tree->cache_es) {
 		es1 = tree->cache_es;
-		if (in_range(es->es_lblk, es1->es_lblk, es1->es_len)) {
+		if (in_range(lblk, es1->es_lblk, es1->es_len)) {
 			es_debug("%u cached by [%u/%u) %llu %llx\n",
-				 es->es_lblk, es1->es_lblk, es1->es_len,
+				 lblk, es1->es_lblk, es1->es_len,
 				 ext4_es_pblock(es1), ext4_es_status(es1));
 			goto out;
 		}
 	}
 
-	es1 = __es_tree_search(&tree->root, es->es_lblk);
+	es1 = __es_tree_search(&tree->root, lblk);
 
 out:
-	if (es1) {
+	if (es1 && !ext4_es_is_delayed(es1)) {
+		while ((node = rb_next(&es1->rb_node)) != NULL) {
+			es1 = rb_entry(node, struct extent_status, rb_node);
+			if (ext4_es_is_delayed(es1))
+				break;
+		}
+	}
+
+	if (es1 && ext4_es_is_delayed(es1)) {
 		tree->cache_es = es1;
 		es->es_lblk = es1->es_lblk;
 		es->es_len = es1->es_len;
 		es->es_pblk = es1->es_pblk;
-		node = rb_next(&es1->rb_node);
-		if (node) {
-			es1 = rb_entry(node, struct extent_status, rb_node);
-			ret = es1->es_lblk;
-		}
 	}
 
 	read_unlock(&EXT4_I(inode)->i_es_lock);
 
-	trace_ext4_es_find_extent_exit(inode, es, ret);
-	return ret;
+	trace_ext4_es_find_delayed_extent_exit(inode, es);
 }
 
 static struct extent_status *

fs/ext4/extents_status.h

···
 				 unsigned long long status);
 extern int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
 				 ext4_lblk_t len);
-extern ext4_lblk_t ext4_es_find_extent(struct inode *inode,
-				struct extent_status *es);
+extern void ext4_es_find_delayed_extent(struct inode *inode, ext4_lblk_t lblk,
+					struct extent_status *es);
 
 static inline int ext4_es_is_written(struct extent_status *es)
 {

fs/ext4/file.c

···
 		 * If there is a delay extent at this offset,
 		 * it will be as a data.
 		 */
-		es.es_lblk = last;
-		(void)ext4_es_find_extent(inode, &es);
+		ext4_es_find_delayed_extent(inode, last, &es);
 		if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
 			if (last != start)
 				dataoff = last << blkbits;
···
 		 * If there is a delay extent at this offset,
 		 * we will skip this extent.
 		 */
-		es.es_lblk = last;
-		(void)ext4_es_find_extent(inode, &es);
+		ext4_es_find_delayed_extent(inode, last, &es);
 		if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {
 			last = es.es_lblk + es.es_len;
 			holeoff = last << blkbits;

include/trace/events/ext4.h

···
 		  __entry->lblk, __entry->len)
 );
 
-TRACE_EVENT(ext4_es_find_extent_enter,
+TRACE_EVENT(ext4_es_find_delayed_extent_enter,
 	TP_PROTO(struct inode *inode, ext4_lblk_t lblk),
 
 	TP_ARGS(inode, lblk),
···
 		  (unsigned long) __entry->ino, __entry->lblk)
 );
 
-TRACE_EVENT(ext4_es_find_extent_exit,
-	TP_PROTO(struct inode *inode, struct extent_status *es,
-		 ext4_lblk_t ret),
+TRACE_EVENT(ext4_es_find_delayed_extent_exit,
+	TP_PROTO(struct inode *inode, struct extent_status *es),
 
-	TP_ARGS(inode, es, ret),
+	TP_ARGS(inode, es),
 
 	TP_STRUCT__entry(
 		__field(	dev_t,		dev		)
···
 		__field(	ext4_lblk_t,	len		)
 		__field(	ext4_fsblk_t,	pblk		)
 		__field(	unsigned long long, status	)
-		__field(	ext4_lblk_t,	ret		)
 	),
 
 	TP_fast_assign(
···
 		__entry->len	= es->es_len;
 		__entry->pblk	= ext4_es_pblock(es);
 		__entry->status	= ext4_es_status(es);
-		__entry->ret	= ret;
 	),
 
-	TP_printk("dev %d,%d ino %lu es [%u/%u) mapped %llu status %llx ret %u",
+	TP_printk("dev %d,%d ino %lu es [%u/%u) mapped %llu status %llx",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  (unsigned long) __entry->ino,
 		  __entry->lblk, __entry->len,
-		  __entry->pblk, __entry->status, __entry->ret)
+		  __entry->pblk, __entry->status)
 );
 
 #endif /* _TRACE_EXT4_H */