Messages in this thread | | | From | "Matthew Wilcox (Oracle)" <> | Subject | [PATCH 0/7] Fix a pile of 4GB file problems on 32-bit | Date | Sun, 4 Oct 2020 19:04:21 +0100 |
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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
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