On 4/8/20 8:30 AM, Dmitry Kadashev wrote: > On Wed, Apr 8, 2020 at 10:19 PM Jens Axboe <axboe@xxxxxxxxx> wrote: >> >> On 4/8/20 7:51 AM, Dmitry Kadashev wrote: >>> Hi, >>> >>> io_uring's openat seems to produce FDs that are incompatible with >>> large files (>2GB). If a file (smaller than 2GB) is opened using >>> io_uring's openat then writes -- both using io_uring and just sync >>> pwrite() -- past that threshold fail with EFBIG. If such a file is >>> opened with sync openat, then both io_uring's writes and sync writes >>> succeed. And if the file is larger than 2GB then io_uring's openat >>> fails right away, while the sync one works. >>> >>> Kernel versions: 5.6.0-rc2, 5.6.0. >>> >>> A couple of reproducers attached, one demos successful open with >>> failed writes afterwards, and another failing open (in comparison with >>> sync calls). >>> >>> The output of the former one for example: >>> >>> *** sync openat >>> openat succeeded >>> sync write at offset 0 >>> write succeeded >>> sync write at offset 4294967296 >>> write succeeded >>> >>> *** sync openat >>> openat succeeded >>> io_uring write at offset 0 >>> write succeeded >>> io_uring write at offset 4294967296 >>> write succeeded >>> >>> *** io_uring openat >>> openat succeeded >>> sync write at offset 0 >>> write succeeded >>> sync write at offset 4294967296 >>> write failed: File too large >>> >>> *** io_uring openat >>> openat succeeded >>> io_uring write at offset 0 >>> write succeeded >>> io_uring write at offset 4294967296 >>> write failed: File too large >> >> Can you try with this one? Seems like only openat2 gets it set, >> not openat... > > I've tried specifying O_LARGEFILE explicitly, that did not change the > behavior. Is this good enough? Much faster for me to check this way > that rebuilding the kernel. But if necessary I can do that. Not sure O_LARGEFILE settings is going to do it for x86-64, the patch should fix it though. Might have worked on 32-bit, though. > Also, forgot to mention, this is on x86_64, not sure if O_LARGEFILE is > necessary to do 2G+ files there? Internally, yes. -- Jens Axboe
