btrfs: Fix error handling in zlib

Return failure if alloc_page() fails to allocate memory,
and the upper code will just give up compression.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index e5b8b22..b015586 100644 (file)
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -225,6 +225,10 @@ int btrfs_zlib_compress_pages(struct address_space *mapping,
        data_in = kmap(in_page);
 
        out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+       if (out_page == NULL) {
+               ret = -1;
+               goto out;
+       }
        cpage_out = kmap(out_page);
        pages[0] = out_page;
        nr_pages = 1;
@@ -263,6 +267,10 @@ int btrfs_zlib_compress_pages(struct address_space *mapping,
                                goto out;
                        }
                        out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+                       if (out_page == NULL) {
+                               ret = -1;
+                               goto out;
+                       }
                        cpage_out = kmap(out_page);
                        pages[nr_pages] = out_page;
                        nr_pages++;