Btrfs: kill the start argument to read_extent_buffer_pages

Nobody uses this, it makes no sense to do partial reads of extent buffers.
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

@@ -442,7 +442,7 @@ static int btrfs_check_super_csum(char *raw_disk_sb)
  */
 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
 					  struct extent_buffer *eb,
-					  u64 start, u64 parent_transid)
+					  u64 parent_transid)
 {
 	struct extent_io_tree *io_tree;
 	int failed = 0;
@@ -454,8 +454,7 @@ static int btree_read_extent_buffer_pages(struct btrfs_root *root,
 	clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
 	io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
 	while (1) {
-		ret = read_extent_buffer_pages(io_tree, eb, start,
-					       WAIT_COMPLETE,
+		ret = read_extent_buffer_pages(io_tree, eb, WAIT_COMPLETE,
 					       btree_get_extent, mirror_num);
 		if (!ret) {
 			if (!verify_parent_transid(io_tree, eb,
@@ -1132,7 +1131,7 @@ void readahead_tree_block(struct btrfs_root *root, u64 bytenr)
 	if (IS_ERR(buf))
 		return;
 	read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
-				 buf, 0, WAIT_NONE, btree_get_extent, 0);
+				 buf, WAIT_NONE, btree_get_extent, 0);
 	free_extent_buffer(buf);
 }
 
@@ -1150,7 +1149,7 @@ int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr,
 
 	set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
 
-	ret = read_extent_buffer_pages(io_tree, buf, 0, WAIT_PAGE_LOCK,
+	ret = read_extent_buffer_pages(io_tree, buf, WAIT_PAGE_LOCK,
 				       btree_get_extent, mirror_num);
 	if (ret) {
 		free_extent_buffer(buf);
@@ -1206,7 +1205,7 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 	if (IS_ERR(buf))
 		return buf;
 
-	ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
+	ret = btree_read_extent_buffer_pages(root, buf, parent_transid);
 	if (ret) {
 		free_extent_buffer(buf);
 		return ERR_PTR(ret);
@@ -4081,7 +4080,7 @@ void btrfs_btree_balance_dirty_nodelay(struct btrfs_root *root)
 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
 {
 	struct btrfs_root *root = BTRFS_I(buf->pages[0]->mapping->host)->root;
-	return btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
+	return btree_read_extent_buffer_pages(root, buf, parent_transid);
 }
 
 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,

fs/btrfs/extent_io.c

@@ -5188,11 +5188,10 @@ int extent_buffer_uptodate(struct extent_buffer *eb)
 }
 
 int read_extent_buffer_pages(struct extent_io_tree *tree,
-			     struct extent_buffer *eb, u64 start, int wait,
+			     struct extent_buffer *eb, int wait,
 			     get_extent_t *get_extent, int mirror_num)
 {
 	unsigned long i;
-	unsigned long start_i;
 	struct page *page;
 	int err;
 	int ret = 0;
@@ -5206,16 +5205,8 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 	if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
 		return 0;
 
-	if (start) {
-		WARN_ON(start < eb->start);
-		start_i = (start >> PAGE_SHIFT) -
-			(eb->start >> PAGE_SHIFT);
-	} else {
-		start_i = 0;
-	}
-
 	num_pages = num_extent_pages(eb->start, eb->len);
-	for (i = start_i; i < num_pages; i++) {
+	for (i = 0; i < num_pages; i++) {
 		page = eb->pages[i];
 		if (wait == WAIT_NONE) {
 			if (!trylock_page(page))
@@ -5230,7 +5221,7 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 	 * the uptodate bit of our pages won't be affected by
 	 * clear_extent_buffer_uptodate().
 	 */
-	for (i = start_i; i < num_pages; i++) {
+	for (i = 0; i < num_pages; i++) {
 		page = eb->pages[i];
 		if (!PageUptodate(page)) {
 			num_reads++;
@@ -5239,7 +5230,6 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 	}
 
 	if (all_uptodate) {
-		if (start_i == 0)
 		set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
 		goto unlock_exit;
 	}
@@ -5247,7 +5237,7 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 	clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
 	eb->read_mirror = 0;
 	atomic_set(&eb->io_pages, num_reads);
-	for (i = start_i; i < num_pages; i++) {
+	for (i = 0; i < num_pages; i++) {
 		page = eb->pages[i];
 
 		if (!PageUptodate(page)) {
@@ -5288,7 +5278,7 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 	if (ret || wait != WAIT_COMPLETE)
 		return ret;
 
-	for (i = start_i; i < num_pages; i++) {
+	for (i = 0; i < num_pages; i++) {
 		page = eb->pages[i];
 		wait_on_page_locked(page);
 		if (!PageUptodate(page))
@@ -5298,12 +5288,10 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 	return ret;
 
 unlock_exit:
-	i = start_i;
 	while (locked_pages > 0) {
-		page = eb->pages[i];
-		i++;
-		unlock_page(page);
 		locked_pages--;
+		page = eb->pages[locked_pages];
+		unlock_page(page);
 	}
 	return ret;
 }

fs/btrfs/extent_io.h

@@ -359,7 +359,7 @@ void free_extent_buffer_stale(struct extent_buffer *eb);
 #define WAIT_COMPLETE	1
 #define WAIT_PAGE_LOCK	2
 int read_extent_buffer_pages(struct extent_io_tree *tree,
-			     struct extent_buffer *eb, u64 start, int wait,
+			     struct extent_buffer *eb, int wait,
 			     get_extent_t *get_extent, int mirror_num);
 void wait_on_extent_buffer_writeback(struct extent_buffer *eb);