hfsplus: fix overflow in hfsplus_get_block
For filesystems larger than 2TB the final sector number passed to
map_bh might overflow the range representable in a 32-bit data type.
Make sure we use a sector_t for it and the arithmetics calculating it.
Signed-off-by: Christoph Hellwig <hch@tuxera.com>
diff --git a/fs/hfsplus/extents.c b/fs/hfsplus/extents.c
index b1991a2..b9c1a4b 100644
--- a/fs/hfsplus/extents.c
+++ b/fs/hfsplus/extents.c
@@ -209,6 +209,7 @@
struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
int res = -EIO;
u32 ablock, dblock, mask;
+ sector_t sector;
int was_dirty = 0;
int shift;
@@ -255,10 +256,12 @@
done:
dprint(DBG_EXTENT, "get_block(%lu): %llu - %u\n",
inode->i_ino, (long long)iblock, dblock);
+
mask = (1 << sbi->fs_shift) - 1;
- map_bh(bh_result, sb,
- (dblock << sbi->fs_shift) + sbi->blockoffset +
- (iblock & mask));
+ sector = ((sector_t)dblock << sbi->fs_shift) +
+ sbi->blockoffset + (iblock & mask);
+ map_bh(bh_result, sb, sector);
+
if (create) {
set_buffer_new(bh_result);
hip->phys_size += sb->s_blocksize;