Btrfs: fix up read_tree_block to return proper error
The return value of read_tree_block() can confuse callers as it always
returns NULL for either -ENOMEM or -EIO, so it's likely that callers
parse it to a wrong error, for instance, in btrfs_read_tree_root().
This fixes the above issue.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 2ef9a4b..7f83778 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1149,12 +1149,12 @@
buf = btrfs_find_create_tree_block(root, bytenr);
if (!buf)
- return NULL;
+ return ERR_PTR(-ENOMEM);
ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
if (ret) {
free_extent_buffer(buf);
- return NULL;
+ return ERR_PTR(ret);
}
return buf;
@@ -1509,20 +1509,19 @@
generation = btrfs_root_generation(&root->root_item);
root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
generation);
- if (!root->node) {
- ret = -ENOMEM;
+ if (IS_ERR(root->node)) {
+ ret = PTR_ERR(root->node);
goto find_fail;
} else if (!btrfs_buffer_uptodate(root->node, generation, 0)) {
ret = -EIO;
- goto read_fail;
+ free_extent_buffer(root->node);
+ goto find_fail;
}
root->commit_root = btrfs_root_node(root);
out:
btrfs_free_path(path);
return root;
-read_fail:
- free_extent_buffer(root->node);
find_fail:
kfree(root);
alloc_fail:
@@ -2320,8 +2319,11 @@
log_tree_root->node = read_tree_block(tree_root, bytenr,
fs_info->generation + 1);
- if (!log_tree_root->node ||
- !extent_buffer_uptodate(log_tree_root->node)) {
+ if (IS_ERR(log_tree_root->node)) {
+ printk(KERN_ERR "BTRFS: failed to read log tree\n");
+ kfree(log_tree_root);
+ return PTR_ERR(log_tree_root->node);
+ } else if (!extent_buffer_uptodate(log_tree_root->node)) {
printk(KERN_ERR "BTRFS: failed to read log tree\n");
free_extent_buffer(log_tree_root->node);
kfree(log_tree_root);
@@ -2797,8 +2799,8 @@
chunk_root->node = read_tree_block(chunk_root,
btrfs_super_chunk_root(disk_super),
generation);
- if (!chunk_root->node ||
- !test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
+ if (IS_ERR(chunk_root->node) ||
+ !extent_buffer_uptodate(chunk_root->node)) {
printk(KERN_ERR "BTRFS: failed to read chunk root on %s\n",
sb->s_id);
goto fail_tree_roots;
@@ -2834,8 +2836,8 @@
tree_root->node = read_tree_block(tree_root,
btrfs_super_root(disk_super),
generation);
- if (!tree_root->node ||
- !test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
+ if (IS_ERR(tree_root->node) ||
+ !extent_buffer_uptodate(tree_root->node)) {
printk(KERN_WARNING "BTRFS: failed to read tree root on %s\n",
sb->s_id);