Btrfs: Fix integer overflow when calculating bytes_per_bitmap

On ppc64, bytes_per_bitmap will be (65536*8*65536). Hence append UL to
fix integer overflow.

Reviewed-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Feifei Xu <xufeifei@linux.vnet.ibm.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index fa623359d5b811ed4a8977b719501ec54265a1b2..2813ef0718a28ce1716617702a2a15f1f7c1cac3 100644 (file)
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -29,7 +29,7 @@
 #include "inode-map.h"
 #include "volumes.h"
 
-#define BITS_PER_BITMAP                (PAGE_SIZE * 8)
+#define BITS_PER_BITMAP                (PAGE_SIZE * 8UL)
 #define MAX_CACHE_BYTES_PER_GIG        SZ_32K
 
 struct btrfs_trim_range {
@@ -1415,11 +1415,11 @@ static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
                                   u64 offset)
 {
        u64 bitmap_start;
-       u32 bytes_per_bitmap;
+       u64 bytes_per_bitmap;
 
        bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
        bitmap_start = offset - ctl->start;
-       bitmap_start = div_u64(bitmap_start, bytes_per_bitmap);
+       bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
        bitmap_start *= bytes_per_bitmap;
        bitmap_start += ctl->start;
 
@@ -1638,10 +1638,10 @@ static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
        u64 bitmap_bytes;
        u64 extent_bytes;
        u64 size = block_group->key.offset;
-       u32 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
-       u32 max_bitmaps = div_u64(size + bytes_per_bg - 1, bytes_per_bg);
+       u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
+       u64 max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
 
-       max_bitmaps = max_t(u32, max_bitmaps, 1);
+       max_bitmaps = max_t(u64, max_bitmaps, 1);
 
        ASSERT(ctl->total_bitmaps <= max_bitmaps);
 

diff --git a/fs/btrfs/tests/free-space-tests.c b/fs/btrfs/tests/free-space-tests.c
index 0eeb8f3d6b674ba8f67fe54877afde605999fcf3..f3756d6b9ba203d707cb083b349d455c98d279bf 100644 (file)
--- a/fs/btrfs/tests/free-space-tests.c
+++ b/fs/btrfs/tests/free-space-tests.c
@@ -22,7 +22,7 @@
 #include "../disk-io.h"
 #include "../free-space-cache.h"
 
-#define BITS_PER_BITMAP                (PAGE_SIZE * 8)
+#define BITS_PER_BITMAP                (PAGE_SIZE * 8UL)
 
 /*
  * This test just does basic sanity checking, making sure we can add an extent