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 <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Jan kara <jack@suse.cz>

4 files changed, 34 insertions, 31 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 37f94a751ad7..895c19595ecf 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3528,8 +3528,7 @@ static int ext4_find_delalloc_range(struct inode *inode,
 {
 	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 &&
@@ -4568,10 +4567,9 @@ static int ext4_find_delayed_extent(struct inode *inode,
 				    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) {
 		/*
@@ -4592,6 +4590,13 @@ static int ext4_find_delayed_extent(struct inode *inode,
 		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;
 }
 /* fiemap flags we can handle specified here */
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 1f5fd44993e9..76f4351ea821 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -229,59 +229,59 @@ static struct extent_status *__es_tree_search(struct rb_root *root,
 }
 
 /*
- * 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 *
diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h
index 3cad83303adb..3f69d097c6e7 100644
--- a/fs/ext4/extents_status.h
+++ b/fs/ext4/extents_status.h
@@ -51,8 +51,8 @@ extern int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
 				 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)
 {
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 2df9354b105e..7e85a10a6f4f 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -464,8 +464,7 @@ static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)
 		 * 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;
@@ -548,8 +547,7 @@ static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)
 		 * 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;