Btrfs: check if extent buffer is aligned to sectorsize

Thanks to fuzz testing, we can pass an invalid bytenr to extent buffer
via alloc_extent_buffer().  An unaligned eb can have more pages than it
should have, which ends up extent buffer's leak or some corrupted content
in extent buffer.

This adds a warning to let us quickly know what was happening.

Now that alloc_extent_buffer() no more returns NULL, this changes its
caller and callers of its caller to match with the new error
handling.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 1142127f6e5e..7b5d5e8efde6 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1098,7 +1098,7 @@ void readahead_tree_block(struct btrfs_root *root, u64 bytenr)
         struct inode *btree_inode = root->fs_info->btree_inode;
 
         buf = btrfs_find_create_tree_block(root, bytenr);
-        if (!buf)
+        if (IS_ERR(buf))
                 return;
         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
                                  buf, 0, WAIT_NONE, btree_get_extent, 0);
@@ -1114,7 +1114,7 @@ int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr,
         int ret;
 
         buf = btrfs_find_create_tree_block(root, bytenr);
-        if (!buf)
+        if (IS_ERR(buf))
                 return 0;
 
         set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
@@ -1172,8 +1172,8 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
         int ret;
 
         buf = btrfs_find_create_tree_block(root, bytenr);
-        if (!buf)
-                return ERR_PTR(-ENOMEM);
+        if (IS_ERR(buf))
+                return buf;
 
         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
         if (ret) {