[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <lhuh5ynl8z5.fsf@oldenburg.str.redhat.com>
Date: Mon, 04 Aug 2025 11:41:34 +0200
From: Florian Weimer <fweimer@...hat.com>
To: fuse-devel@...ts.sourceforge.net, linux-api@...r.kernel.org,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: copy_file_range return value on FUSE
The FUSE protocol uses struct fuse_write_out to convey the return value
of copy_file_range, which is restricted to uint32_t. But the
copy_file_range interface supports a 64-bit copy operation. Given that
copy_file_range is expected to clone huge files, large copies are not
unexpected, so this appears to be a real limitation.
There is another wrinkle: we'd need to check if the process runs in
32-bit compat mode, and reject size_t arguments larger than INT_MAX in
this case (with EOVERFLOW presumably). But perhaps this should be
handled on the kernel side? Currently, this doesn't seem to happen, and
we can get copy_file_range results in the in-band error range.
Applications have no way to disambiguate this.
Thanks,
Florian
Powered by blists - more mailing lists