Btrfs: check return value of lookup_extent_mapping() correctly
This patch corrects error checking of lookup_extent_mapping().
Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 14f1c5a..d02c27c 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -588,6 +588,8 @@
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);
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index b05d35a..8d6f55f 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3308,7 +3308,7 @@
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;
}
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index d8f282b..cd040bf 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1954,7 +1954,7 @@
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;