ext2fs_group_first_block2() returns the product of the group number
and the number of blocks per group (from the superblock). Unfortunately,
both of these are 32-bit quantities, so the multiplication result is
also 32 bits wide. It is then returned as a 64-bit quantity, but by then,
it's too late.
Cast one of the operands to blk64_t, so the multiplication will be done
in 64 bits.
e2fsck was complaining about a group that was marked BLOCK_UNINIT, but
had blocks in use (it turned out that a different group had blocks in
use, but the block numbers of the two different groups differed by
2^32, so this bug conflated them). With this change, this complaint
goes away. In addition, dumpe2fs produces the right blocks for all the
groups, whereas it was wrapping them at the 32-bit boundary previously.
Signed-off-by: Nick Dokos <nicholas.dokos@xxxxxx>
---
lib/ext2fs/blknum.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/lib/ext2fs/blknum.c b/lib/ext2fs/blknum.c
index b9666fb..fd56d53 100644
--- a/lib/ext2fs/blknum.c
+++ b/lib/ext2fs/blknum.c
@@ -28,7 +28,7 @@ dgrp_t ext2fs_group_of_blk2(ext2_filsys fs, blk64_t blk)
blk64_t ext2fs_group_first_block2(ext2_filsys fs, dgrp_t group)
{
return fs->super->s_first_data_block +
- (group * fs->super->s_blocks_per_group);
+ ((blk64_t)group * fs->super->s_blocks_per_group);
}
/*
--
1.6.0.6
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