btrfs: reada: Use fs_info instead of root in __readahead_hook's argument

What __readahead_hook() need exactly is fs_info, no need to convert
fs_info to root in caller and convert back in __readahead_hook()

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -4525,8 +4525,8 @@ struct reada_control *btrfs_reada_add(struct btrfs_root *root,
 			      struct btrfs_key *start, struct btrfs_key *end);
 int btrfs_reada_wait(void *handle);
 void btrfs_reada_detach(void *handle);
-int btree_readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
-			 u64 start, int err);
+int btree_readahead_hook(struct btrfs_fs_info *fs_info,
+			 struct extent_buffer *eb, u64 start, int err);
 
 static inline int is_fstree(u64 rootid)
 {

fs/btrfs/disk-io.c

@@ -612,6 +612,7 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
 	int found_level;
 	struct extent_buffer *eb;
 	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
+	struct btrfs_fs_info *fs_info = root->fs_info;
 	int ret = 0;
 	int reads_done;
 
@@ -637,21 +638,21 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
 
 	found_start = btrfs_header_bytenr(eb);
 	if (found_start != eb->start) {
-		btrfs_err_rl(eb->fs_info, "bad tree block start %llu %llu",
-			       found_start, eb->start);
+		btrfs_err_rl(fs_info, "bad tree block start %llu %llu",
+			     found_start, eb->start);
 		ret = -EIO;
 		goto err;
 	}
-	if (check_tree_block_fsid(root->fs_info, eb)) {
-		btrfs_err_rl(eb->fs_info, "bad fsid on block %llu",
-			       eb->start);
+	if (check_tree_block_fsid(fs_info, eb)) {
+		btrfs_err_rl(fs_info, "bad fsid on block %llu",
+			     eb->start);
 		ret = -EIO;
 		goto err;
 	}
 	found_level = btrfs_header_level(eb);
 	if (found_level >= BTRFS_MAX_LEVEL) {
-		btrfs_err(root->fs_info, "bad tree block level %d",
-			   (int)btrfs_header_level(eb));
+		btrfs_err(fs_info, "bad tree block level %d",
+			  (int)btrfs_header_level(eb));
 		ret = -EIO;
 		goto err;
 	}
@@ -659,7 +660,7 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
 	btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb),
 				       eb, found_level);
 
-	ret = csum_tree_block(root->fs_info, eb, 1);
+	ret = csum_tree_block(fs_info, eb, 1);
 	if (ret) {
 		ret = -EIO;
 		goto err;
@@ -680,7 +681,7 @@ static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
 err:
 	if (reads_done &&
 	    test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
-		btree_readahead_hook(root, eb, eb->start, ret);
+		btree_readahead_hook(fs_info, eb, eb->start, ret);
 
 	if (ret) {
 		/*
@@ -699,14 +700,13 @@ out:
 static int btree_io_failed_hook(struct page *page, int failed_mirror)
 {
 	struct extent_buffer *eb;
-	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 
 	eb = (struct extent_buffer *)page->private;
 	set_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
 	eb->read_mirror = failed_mirror;
 	atomic_dec(&eb->io_pages);
 	if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
-		btree_readahead_hook(root, eb, eb->start, -EIO);
+		btree_readahead_hook(eb->fs_info, eb, eb->start, -EIO);
 	return -EIO;	/* we fixed nothing */
 }
 

fs/btrfs/reada.c

@@ -105,15 +105,15 @@ static int reada_add_block(struct reada_control *rc, u64 logical,
 
 /* recurses */
 /* in case of err, eb might be NULL */
-static void __readahead_hook(struct btrfs_root *root, struct reada_extent *re,
-			     struct extent_buffer *eb, u64 start, int err)
+static void __readahead_hook(struct btrfs_fs_info *fs_info,
+			     struct reada_extent *re, struct extent_buffer *eb,
+			     u64 start, int err)
 {
 	int level = 0;
 	int nritems;
 	int i;
 	u64 bytenr;
 	u64 generation;
-	struct btrfs_fs_info *fs_info = root->fs_info;
 	struct list_head list;
 	struct btrfs_device *for_dev;
 
@@ -176,10 +176,10 @@ static void __readahead_hook(struct btrfs_root *root, struct reada_extent *re,
 			 */
 #ifdef DEBUG
 			if (rec->generation != generation) {
-				btrfs_debug(root->fs_info,
-					   "generation mismatch for (%llu,%d,%llu) %llu != %llu",
-				       key.objectid, key.type, key.offset,
-				       rec->generation, generation);
+				btrfs_debug(fs_info,
+					    "generation mismatch for (%llu,%d,%llu) %llu != %llu",
+					    key.objectid, key.type, key.offset,
+					    rec->generation, generation);
 			}
 #endif
 			if (rec->generation == generation &&
@@ -220,12 +220,11 @@ static void __readahead_hook(struct btrfs_root *root, struct reada_extent *re,
  * start is passed separately in case eb in NULL, which may be the case with
  * failed I/O
  */
-int btree_readahead_hook(struct btrfs_root *root, struct extent_buffer *eb,
-			 u64 start, int err)
+int btree_readahead_hook(struct btrfs_fs_info *fs_info,
+			 struct extent_buffer *eb, u64 start, int err)
 {
 	int ret = 0;
 	struct reada_extent *re;
-	struct btrfs_fs_info *fs_info = root->fs_info;
 
 	/* find extent */
 	spin_lock(&fs_info->reada_lock);
@@ -724,9 +723,9 @@ static int reada_start_machine_dev(struct btrfs_fs_info *fs_info,
 	ret = reada_tree_block_flagged(fs_info->extent_root, logical,
 			mirror_num, &eb);
 	if (ret)
-		__readahead_hook(fs_info->extent_root, re, NULL, logical, ret);
+		__readahead_hook(fs_info, re, NULL, logical, ret);
 	else if (eb)
-		__readahead_hook(fs_info->extent_root, re, eb, eb->start, ret);
+		__readahead_hook(fs_info, re, eb, eb->start, ret);
 
 	if (eb)
 		free_extent_buffer(eb);