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Miklos Szeredi authored
fuse_direct_io() can end up advancing the iterator by more than the amount of data read or written. This case is handled by the generic code if going through ->direct_IO(), but not in the FOPEN_DIRECT_IO case. Fix by reverting the extra bytes from the iterator in case of error or a short count. To test: install lxcfs, then the following testcase int fd = open("/var/lib/lxcfs/proc/uptime", O_RDONLY); sendfile(1, fd, NULL, 16777216); sendfile(1, fd, NULL, 16777216); will spew WARN_ON() in iov_iter_pipe(). Reported-by:
Peter Geis <pgwipeout@gmail.com> Reported-by:
Al Viro <viro@zeniv.linux.org.uk> Fixes: 3c3db095 ("fuse: use iov_iter based generic splice helpers") Cc: <stable@vger.kernel.org> # v5.1 Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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