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

commit 89b1f39eb4189de745fae554b0d614d87c8d5c63 upstream.

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>
Cc: Jim Trigg <jtrigg@spamcop.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index 4858c191242b7a4180f90b5e080606685b9cebb3..54706dca277bb6772e30f363752838a5de225e42 100644 (file)
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -79,7 +79,7 @@ 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;
 };