This patchset tries to add new IO_URING test into fsstress [1/4] and fsx [4/4]. And then do some changes and bug fix by the way [2/4 and 3/4]. fsstress and fsx are important tools in xfstests to do filesystem I/Os test, lots of test cases use it. So add IO_URING operation into fsstress and fsx will help to cover IO_URING test from fs side. I'm not an IO_URING expert, so cc io-uring@ list, please feel free to tell me if you find something wrong or have any suggestions to improve the test. V2 did below changes: 1) 1/4 change the definition of URING_ENTRIES to 1 2) 2/4 change the difinition of AIO_ENTRIES to 1, undo an unrelated changed line 3) 4/4 turn to use io_uring_prep_readv/io_uring_prep_writev, due to old liburing(0.2-2) doesn't support io_uring_prep_read/io_uring_prep_write. V3 changed io_uring_submit(&ring) to io_uring_submit_and_wait(&ring, 1). I'm not sure if this's the real mean of Jens Axboe's review point, please check. https://marc.info/?l=fstests&m=159811932808057&w=2 Thanks, Zorro