Btrfs: check return value of lookup_extent_mapping() correctly
Tsutomu Itoh [Thu, 16 Feb 2012 07:23:58 +0000 (16:23 +0900)]
This patch corrects error checking of lookup_extent_mapping().

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>

fs/btrfs/compression.c
fs/btrfs/extent_io.c
fs/btrfs/volumes.c

index 14f1c5a..d02c27c 100644 (file)
@@ -588,6 +588,8 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
                                   page_offset(bio->bi_io_vec->bv_page),
                                   PAGE_CACHE_SIZE);
        read_unlock(&em_tree->lock);
+       if (!em)
+               return -EIO;
 
        compressed_len = em->block_len;
        cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
index b05d35a..8d6f55f 100644 (file)
@@ -3308,7 +3308,7 @@ int try_release_extent_mapping(struct extent_map_tree *map,
                        len = end - start + 1;
                        write_lock(&map->lock);
                        em = lookup_extent_mapping(map, start, len);
-                       if (IS_ERR_OR_NULL(em)) {
+                       if (!em) {
                                write_unlock(&map->lock);
                                break;
                        }
index d8f282b..cd040bf 100644 (file)
@@ -1954,7 +1954,7 @@ static int btrfs_relocate_chunk(struct btrfs_root *root,
        em = lookup_extent_mapping(em_tree, chunk_offset, 1);
        read_unlock(&em_tree->lock);
 
-       BUG_ON(em->start > chunk_offset ||
+       BUG_ON(!em || em->start > chunk_offset ||
               em->start + em->len < chunk_offset);
        map = (struct map_lookup *)em->bdev;