udf: Fix bitmap overflow on large filesystems with small block size

For large UDF filesystems with 512-byte blocks the number of necessary
bitmap blocks is larger than 2^16 so s_nr_groups in udf_bitmap overflows
(the number will overflow for filesystems larger than 128 GB with
512-byte blocks). That results in ENOSPC errors despite the filesystem
has plenty of free space.

Fix the problem by changing s_nr_groups' type to 'int'. That is enough
even for filesystems 2^32 blocks (UDF maximum) and 512-byte blocksize.

Reported-and-tested-by: v10lator@myway.de
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index 5f027227f085464d33b2434a1cad64a44195c54d..8d1c9d4f439ee83395e7114e19248750f688fbf5 100644 (file)
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -82,7 +82,7 @@ struct udf_virtual_data {
 struct udf_bitmap {
        __u32                   s_extLength;
        __u32                   s_extPosition;
-       __u16                   s_nr_groups;
+       int                     s_nr_groups;
        struct buffer_head      **s_block_bitmap;
 };