fix ufs_isblockset()

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 7 insertions, 3 deletions

diff --git a/fs/ufs/util.h b/fs/ufs/util.h
index b7fbf53dbc81..398019fb1448 100644
--- a/fs/ufs/util.h
+++ b/fs/ufs/util.h
@@ -473,15 +473,19 @@ static inline unsigned _ubh_find_last_zero_bit_(
 static inline int _ubh_isblockset_(struct ufs_sb_private_info * uspi,
         struct ufs_buffer_head * ubh, unsigned begin, unsigned block)
 {
+        u8 mask;
         switch (uspi->s_fpb) {
         case 8:
                 return (*ubh_get_addr (ubh, begin + block) == 0xff);
         case 4:
-                return (*ubh_get_addr (ubh, begin + (block >> 1)) == (0x0f << ((block & 0x01) << 2)));
+                mask = 0x0f << ((block & 0x01) << 2);
+                return (*ubh_get_addr (ubh, begin + (block >> 1)) & mask) == mask;
         case 2:
-                return (*ubh_get_addr (ubh, begin + (block >> 2)) == (0x03 << ((block & 0x03) << 1)));
+                mask = 0x03 << ((block & 0x03) << 1);
+                return (*ubh_get_addr (ubh, begin + (block >> 2)) & mask) == mask;
         case 1:
-                return (*ubh_get_addr (ubh, begin + (block >> 3)) == (0x01 << (block & 0x07)));
+                mask = 0x01 << (block & 0x07);
+                return (*ubh_get_addr (ubh, begin + (block >> 3)) & mask) == mask;
         }
         return 0;       
 }