super-0.90: don't write bitmap larger than 60K From: NeilBrown The 4K superblock can be as close as 64K from the end of the device. As the bitmap (with header) lives after the superblock (with 0.90 metadata) there could be as little as 60K of space. So limit the bitmaps to 59.5K, and only write 60K including the header. The bug fixed here means that bitmaps cannot be created on devices which are exact multiples of 64K in size Signed-off-by: NeilBrown --- super0.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/super0.c b/super0.c index 07f4792..8555992 100644 --- a/super0.c +++ b/super0.c @@ -942,7 +942,7 @@ static int add_internal_bitmap0(struct supertype *st, int *chunkp, * size is in sectors, chunk is in bytes !!! */ unsigned long long bits; - unsigned long long max_bits = 60*1024*8; + unsigned long long max_bits = (60*1024 - sizeof(bitmap_super_t))*8; unsigned long long min_chunk; int chunk = *chunkp; mdp_super_t *sb = st->sb; @@ -1023,7 +1023,7 @@ static int write_bitmap0(struct supertype *st, int fd) memset(buf, 0xff, 4096); memcpy(buf, ((char*)sb)+MD_SB_BYTES, sizeof(bitmap_super_t)); - towrite = 64*1024; + towrite = 60*1024; while (towrite > 0) { n = towrite; if (n > 4096)