ext4: add physical block and status member into extent status tree

This commit adds two members in extent_status structure to let it record
physical block and extent status.  Here es_pblk is used to record both
of them because physical block only has 48 bits.  So extent status could
be stashed into it so that we can save some memory.  Now written,
unwritten, delayed and hole are defined as status.

Due to new member is added into extent status tree, all interfaces need
to be adjusted.

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

1 files changed, 55 insertions, 12 deletions

diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index c9921cf..1f5fd44 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -179,7 +179,9 @@ static void ext4_es_print_tree(struct inode *inode)
 	while (node) {
 		struct extent_status *es;
 		es = rb_entry(node, struct extent_status, rb_node);
-		printk(KERN_DEBUG " [%u/%u)", es->es_lblk, es->es_len);
+		printk(KERN_DEBUG " [%u/%u) %llu %llx",
+		       es->es_lblk, es->es_len,
+		       ext4_es_pblock(es), ext4_es_status(es));
 		node = rb_next(node);
 	}
 	printk(KERN_DEBUG "\n");
@@ -234,7 +236,7 @@ static struct extent_status *__es_tree_search(struct rb_root *root,
  * @es: delayed extent that we found
  *
  * Returns the first block of the next extent after es, otherwise
- * EXT_MAX_BLOCKS if no delay extent is found.
+ * 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)
@@ -249,17 +251,18 @@ ext4_lblk_t ext4_es_find_extent(struct inode *inode, struct extent_status *es)
 	read_lock(&EXT4_I(inode)->i_es_lock);
 	tree = &EXT4_I(inode)->i_es_tree;
 
-	/* find delay extent in cache firstly */
+	/* find extent in cache firstly */
+	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)) {
-			es_debug("%u cached by [%u/%u)\n",
-				 es->es_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,
+				 ext4_es_pblock(es1), ext4_es_status(es1));
 			goto out;
 		}
 	}
 
-	es->es_len = 0;
 	es1 = __es_tree_search(&tree->root, es->es_lblk);
 
 out:
@@ -267,6 +270,7 @@ out:
 		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);
@@ -281,7 +285,7 @@ out:
 }
 
 static struct extent_status *
-ext4_es_alloc_extent(ext4_lblk_t lblk, ext4_lblk_t len)
+ext4_es_alloc_extent(ext4_lblk_t lblk, ext4_lblk_t len, ext4_fsblk_t pblk)
 {
 	struct extent_status *es;
 	es = kmem_cache_alloc(ext4_es_cachep, GFP_ATOMIC);
@@ -289,6 +293,7 @@ ext4_es_alloc_extent(ext4_lblk_t lblk, ext4_lblk_t len)
 		return NULL;
 	es->es_lblk = lblk;
 	es->es_len = len;
+	es->es_pblk = pblk;
 	return es;
 }
 
@@ -301,6 +306,8 @@ static void ext4_es_free_extent(struct extent_status *es)
  * Check whether or not two extents can be merged
  * Condition:
  *  - logical block number is contiguous
+ *  - physical block number is contiguous
+ *  - status is equal
  */
 static int ext4_es_can_be_merged(struct extent_status *es1,
 				 struct extent_status *es2)
@@ -308,6 +315,13 @@ static int ext4_es_can_be_merged(struct extent_status *es1,
 	if (es1->es_lblk + es1->es_len != es2->es_lblk)
 		return 0;
 
+	if (ext4_es_status(es1) != ext4_es_status(es2))
+		return 0;
+
+	if ((ext4_es_is_written(es1) || ext4_es_is_unwritten(es1)) &&
+	    (ext4_es_pblock(es1) + es1->es_len != ext4_es_pblock(es2)))
+		return 0;
+
 	return 1;
 }
 
@@ -371,6 +385,10 @@ static int __es_insert_extent(struct ext4_es_tree *tree,
 				 */
 				es->es_lblk = newes->es_lblk;
 				es->es_len += newes->es_len;
+				if (ext4_es_is_written(es) ||
+				    ext4_es_is_unwritten(es))
+					ext4_es_store_pblock(es,
+							     newes->es_pblk);
 				es = ext4_es_try_to_merge_left(tree, es);
 				goto out;
 			}
@@ -388,7 +406,8 @@ static int __es_insert_extent(struct ext4_es_tree *tree,
 		}
 	}
 
-	es = ext4_es_alloc_extent(newes->es_lblk, newes->es_len);
+	es = ext4_es_alloc_extent(newes->es_lblk, newes->es_len,
+				  newes->es_pblk);
 	if (!es)
 		return -ENOMEM;
 	rb_link_node(&es->rb_node, parent, p);
@@ -408,21 +427,24 @@ out:
  * Return 0 on success, error code on failure.
  */
 int ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
-			  ext4_lblk_t len)
+			  ext4_lblk_t len, ext4_fsblk_t pblk,
+			  unsigned long long status)
 {
 	struct ext4_es_tree *tree;
 	struct extent_status newes;
 	ext4_lblk_t end = lblk + len - 1;
 	int err = 0;
 
-	trace_ext4_es_insert_extent(inode, lblk, len);
-	es_debug("add [%u/%u) to extent status tree of inode %lu\n",
-		 lblk, len, inode->i_ino);
+	es_debug("add [%u/%u) %llu %llx to extent status tree of inode %lu\n",
+		 lblk, len, pblk, status, inode->i_ino);
 
 	BUG_ON(end < lblk);
 
 	newes.es_lblk = lblk;
 	newes.es_len = len;
+	ext4_es_store_pblock(&newes, pblk);
+	ext4_es_store_status(&newes, status);
+	trace_ext4_es_insert_extent(inode, &newes);
 
 	write_lock(&EXT4_I(inode)->i_es_lock);
 	tree = &EXT4_I(inode)->i_es_tree;
@@ -446,6 +468,7 @@ static int __es_remove_extent(struct ext4_es_tree *tree, ext4_lblk_t lblk,
 	struct extent_status *es;
 	struct extent_status orig_es;
 	ext4_lblk_t len1, len2;
+	ext4_fsblk_t block;
 	int err = 0;
 
 	es = __es_tree_search(&tree->root, lblk);
@@ -459,6 +482,8 @@ static int __es_remove_extent(struct ext4_es_tree *tree, ext4_lblk_t lblk,
 
 	orig_es.es_lblk = es->es_lblk;
 	orig_es.es_len = es->es_len;
+	orig_es.es_pblk = es->es_pblk;
+
 	len1 = lblk > es->es_lblk ? lblk - es->es_lblk : 0;
 	len2 = ext4_es_end(es) > end ? ext4_es_end(es) - end : 0;
 	if (len1 > 0)
@@ -469,6 +494,13 @@ static int __es_remove_extent(struct ext4_es_tree *tree, ext4_lblk_t lblk,
 
 			newes.es_lblk = end + 1;
 			newes.es_len = len2;
+			if (ext4_es_is_written(&orig_es) ||
+			    ext4_es_is_unwritten(&orig_es)) {
+				block = ext4_es_pblock(&orig_es) +
+					orig_es.es_len - len2;
+				ext4_es_store_pblock(&newes, block);
+			}
+			ext4_es_store_status(&newes, ext4_es_status(&orig_es));
 			err = __es_insert_extent(tree, &newes);
 			if (err) {
 				es->es_lblk = orig_es.es_lblk;
@@ -478,6 +510,11 @@ static int __es_remove_extent(struct ext4_es_tree *tree, ext4_lblk_t lblk,
 		} else {
 			es->es_lblk = end + 1;
 			es->es_len = len2;
+			if (ext4_es_is_written(es) ||
+			    ext4_es_is_unwritten(es)) {
+				block = orig_es.es_pblk + orig_es.es_len - len2;
+				ext4_es_store_pblock(es, block);
+			}
 		}
 		goto out;
 	}
@@ -502,9 +539,15 @@ static int __es_remove_extent(struct ext4_es_tree *tree, ext4_lblk_t lblk,
 	}
 
 	if (es && es->es_lblk < end + 1) {
+		ext4_lblk_t orig_len = es->es_len;
+
 		len1 = ext4_es_end(es) - end;
 		es->es_lblk = end + 1;
 		es->es_len = len1;
+		if (ext4_es_is_written(es) || ext4_es_is_unwritten(es)) {
+			block = es->es_pblk + orig_len - len1;
+			ext4_es_store_pblock(es, block);
+		}
 	}
 
 out: