[PATCH V2 2/8] Btrfs: Fix integer overflow when calculating bytes_per_bitmap

[Feifei Xu]

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

Reviewed-by: Chandan Rajendra <chan...@linux.vnet.ibm.com>
Signed-off-by: Feifei Xu <xufei...@linux.vnet.ibm.com>
---
 fs/btrfs/free-space-cache.c       | 12 ++++++------
 fs/btrfs/tests/free-space-tests.c |  2 +-
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index fa62335..2813ef0 100644
--- 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 0eeb8f3..f3756d6 100644
--- 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
-- 
2.7.4

--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html