On Sun, Oct 04, 2020 at 07:04:28PM +0100, Matthew Wilcox (Oracle) wrote:
On 32-bit systems, these shifts will overflow for files larger than 4GB. Add helper functions to avoid this problem coming back.
Cc: stable@vger.kernel.org Fixes: 73ff61dbe5ed ("Btrfs: fix device replace of a missing RAID 5/6 device") Fixes: be50a8ddaae1 ("Btrfs: Simplify scrub_setup_recheck_block()'s argument") Fixes: ff023aac3119 ("Btrfs: add code to scrub to copy read data to another disk") Fixes: b5d67f64f9bc ("Btrfs: change scrub to support big blocks") Fixes: a2de733c78fa ("btrfs: scrub") Signed-off-by: Matthew Wilcox (Oracle) willy@infradead.org
fs/btrfs/scrub.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index 354ab9985a34..ccbaf9c6e87a 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -1262,12 +1262,17 @@ static inline void scrub_stripe_index_and_offset(u64 logical, u64 map_type, } } +static u64 sblock_length(struct scrub_block *sblock) +{
- return (u64)sblock->page_count * PAGE_SIZE;
page_count will be 32 at most, the type is int and this will never overflow. The value is usualy number of pages in the arrays scrub_bio::pagev or scrub_block::pagev bounded by SCRUB_PAGES_PER_WR_BIO (32) or SCRUB_MAX_PAGES_PER_BLOCK (16). The scrub code does not use mappings and it reads raw blocks to own pages and does the checksum verification.