[0/7] Fix a pile of 4GB file problems on 32-bit

Message

Matthew Wilcox (Oracle) Oct. 4, 2020, 6:04 p.m. UTC

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(-)