1 files changed, 131 insertions, 18 deletions

diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index c4e6fb15101b..8530fbd3012d 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -233,30 +233,38 @@ static struct extent_status *__es_tree_search(struct rb_root *root,
 }
 
 /*
- * ext4_es_find_delayed_extent_range: find the 1st delayed extent covering
- * @es->lblk if it exists, otherwise, the next extent after @es->lblk.
+ * ext4_es_find_extent_range - find extent with specified status within block
+ *                             range or next extent following block range in
+ *                             extents status tree
  *
- * @inode: the inode which owns delayed extents
- * @lblk: the offset where we start to search
- * @end: the offset where we stop to search
- * @es: delayed extent that we found
+ * @inode - file containing the range
+ * @matching_fn - pointer to function that matches extents with desired status
+ * @lblk - logical block defining start of range
+ * @end - logical block defining end of range
+ * @es - extent found, if any
+ *
+ * Find the first extent within the block range specified by @lblk and @end
+ * in the extents status tree that satisfies @matching_fn.  If a match
+ * is found, it's returned in @es.  If not, and a matching extent is found
+ * beyond the block range, it's returned in @es.  If no match is found, an
+ * extent is returned in @es whose es_lblk, es_len, and es_pblk components
+ * are 0.
  */
-void ext4_es_find_delayed_extent_range(struct inode *inode,
-				 ext4_lblk_t lblk, ext4_lblk_t end,
-				 struct extent_status *es)
+static void __es_find_extent_range(struct inode *inode,
+				   int (*matching_fn)(struct extent_status *es),
+				   ext4_lblk_t lblk, ext4_lblk_t end,
+				   struct extent_status *es)
 {
 	struct ext4_es_tree *tree = NULL;
 	struct extent_status *es1 = NULL;
 	struct rb_node *node;
 
-	BUG_ON(es == NULL);
-	BUG_ON(end < lblk);
-	trace_ext4_es_find_delayed_extent_range_enter(inode, lblk);
+	WARN_ON(es == NULL);
+	WARN_ON(end < lblk);
 
-	read_lock(&EXT4_I(inode)->i_es_lock);
 	tree = &EXT4_I(inode)->i_es_tree;
 
-	/* find extent in cache firstly */
+	/* see if the extent has been cached */
 	es->es_lblk = es->es_len = es->es_pblk = 0;
 	if (tree->cache_es) {
 		es1 = tree->cache_es;
@@ -271,28 +279,133 @@ void ext4_es_find_delayed_extent_range(struct inode *inode,
 	es1 = __es_tree_search(&tree->root, lblk);
 
 out:
-	if (es1 && !ext4_es_is_delayed(es1)) {
+	if (es1 && !matching_fn(es1)) {
 		while ((node = rb_next(&es1->rb_node)) != NULL) {
 			es1 = rb_entry(node, struct extent_status, rb_node);
 			if (es1->es_lblk > end) {
 				es1 = NULL;
 				break;
 			}
-			if (ext4_es_is_delayed(es1))
+			if (matching_fn(es1))
 				break;
 		}
 	}
 
-	if (es1 && ext4_es_is_delayed(es1)) {
+	if (es1 && matching_fn(es1)) {
 		tree->cache_es = es1;
 		es->es_lblk = es1->es_lblk;
 		es->es_len = es1->es_len;
 		es->es_pblk = es1->es_pblk;
 	}
 
+}
+
+/*
+ * Locking for __es_find_extent_range() for external use
+ */
+void ext4_es_find_extent_range(struct inode *inode,
+			       int (*matching_fn)(struct extent_status *es),
+			       ext4_lblk_t lblk, ext4_lblk_t end,
+			       struct extent_status *es)
+{
+	trace_ext4_es_find_extent_range_enter(inode, lblk);
+
+	read_lock(&EXT4_I(inode)->i_es_lock);
+	__es_find_extent_range(inode, matching_fn, lblk, end, es);
+	read_unlock(&EXT4_I(inode)->i_es_lock);
+
+	trace_ext4_es_find_extent_range_exit(inode, es);
+}
+
+/*
+ * __es_scan_range - search block range for block with specified status
+ *                   in extents status tree
+ *
+ * @inode - file containing the range
+ * @matching_fn - pointer to function that matches extents with desired status
+ * @lblk - logical block defining start of range
+ * @end - logical block defining end of range
+ *
+ * Returns true if at least one block in the specified block range satisfies
+ * the criterion specified by @matching_fn, and false if not.  If at least
+ * one extent has the specified status, then there is at least one block
+ * in the cluster with that status.  Should only be called by code that has
+ * taken i_es_lock.
+ */
+static bool __es_scan_range(struct inode *inode,
+			    int (*matching_fn)(struct extent_status *es),
+			    ext4_lblk_t start, ext4_lblk_t end)
+{
+	struct extent_status es;
+
+	__es_find_extent_range(inode, matching_fn, start, end, &es);
+	if (es.es_len == 0)
+		return false;   /* no matching extent in the tree */
+	else if (es.es_lblk <= start &&
+		 start < es.es_lblk + es.es_len)
+		return true;
+	else if (start <= es.es_lblk && es.es_lblk <= end)
+		return true;
+	else
+		return false;
+}
+/*
+ * Locking for __es_scan_range() for external use
+ */
+bool ext4_es_scan_range(struct inode *inode,
+			int (*matching_fn)(struct extent_status *es),
+			ext4_lblk_t lblk, ext4_lblk_t end)
+{
+	bool ret;
+
+	read_lock(&EXT4_I(inode)->i_es_lock);
+	ret = __es_scan_range(inode, matching_fn, lblk, end);
+	read_unlock(&EXT4_I(inode)->i_es_lock);
+
+	return ret;
+}
+
+/*
+ * __es_scan_clu - search cluster for block with specified status in
+ *                 extents status tree
+ *
+ * @inode - file containing the cluster
+ * @matching_fn - pointer to function that matches extents with desired status
+ * @lblk - logical block in cluster to be searched
+ *
+ * Returns true if at least one extent in the cluster containing @lblk
+ * satisfies the criterion specified by @matching_fn, and false if not.  If at
+ * least one extent has the specified status, then there is at least one block
+ * in the cluster with that status.  Should only be called by code that has
+ * taken i_es_lock.
+ */
+static bool __es_scan_clu(struct inode *inode,
+			  int (*matching_fn)(struct extent_status *es),
+			  ext4_lblk_t lblk)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	ext4_lblk_t lblk_start, lblk_end;
+
+	lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
+	lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
+
+	return __es_scan_range(inode, matching_fn, lblk_start, lblk_end);
+}
+
+/*
+ * Locking for __es_scan_clu() for external use
+ */
+bool ext4_es_scan_clu(struct inode *inode,
+		      int (*matching_fn)(struct extent_status *es),
+		      ext4_lblk_t lblk)
+{
+	bool ret;
+
+	read_lock(&EXT4_I(inode)->i_es_lock);
+	ret = __es_scan_clu(inode, matching_fn, lblk);
 	read_unlock(&EXT4_I(inode)->i_es_lock);
 
-	trace_ext4_es_find_delayed_extent_range_exit(inode, es);
+	return ret;
 }
 
 static void ext4_es_list_add(struct inode *inode)