From 50526e9090d0c118b065840719bc9601be8af8b8 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 7 Jul 2010 21:09:23 +1000 Subject: super-0.90: don't write bitmap larger than 60K 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 file changed, 2 insertions(+), 2 deletions(-) diff --git a/super0.c b/super0.c index 83600cbf..b8dfdb44 100644 --- a/super0.c +++ b/super0.c @@ -962,7 +962,7 @@ 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; @@ -1048,7 +1048,7 @@ 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) -- cgit v1.2.3