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

-- 
Dmitry