I caught a bug in my own code where I forgot to cast to loff_t before shifting. So I thought I'd grep around and see if I could find any other occurrences. I found a few that were clearly bugs, and they're fixed below. There are other places where we don't cast, and I think they're OK. For example, some places we have a 'nr_pages' being shifted by PAGE_SHIFT, and that's probably OK because it's probably a single I/O. Also, I didn't touch AFFS or ROMFS or some other filesystems which probably have never seen a 4GB file in their lives. Might be worth fixing to be sure nobody copies bad code from them, but not worth cc'ing stable for. I didn't look for SECTOR_SHIFT or SECTOR_SIZE (or bare 9/512), just PAGE_SIZE and PAGE_SHIFT. I can't find a GCC warning to enable for this pattern, so I filed https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97287 Matthew Wilcox (Oracle) (7): 9P: Cast to loff_t before multiplying buffer: Promote to unsigned long long before shifting ceph: Promote to unsigned long long before shifting ocfs2: Promote to unsigned long long before shifting btrfs: Promote to unsigned long long before shifting btrfs: Promote to unsigned long long before shifting btrfs: Promote to unsigned long long before multiplying fs/9p/vfs_file.c | 4 ++-- fs/btrfs/ioctl.c | 6 +++--- fs/btrfs/raid56.c | 2 +- fs/btrfs/scrub.c | 25 ++++++++++++++++--------- fs/buffer.c | 2 +- fs/ceph/addr.c | 2 +- fs/ocfs2/alloc.c | 2 +- 7 files changed, 25 insertions(+), 18 deletions(-) -- 2.28.0
