Am 06.05.20 um 14:41 schrieb Anoop C S: > On Wed, 2020-05-06 at 12:33 +0200, Stefan Metzmacher wrote: >> Hi Anoop, >> >>> I could reproduce the difference in SHA256 checksum after copying a >>> directory with 100 copies of test file(provided by reporter) from >>> io_uring VFS module enabled share using Windows explorer(right- >>> click- >>>> copy/paste). Only 5 out of 100 files had correct checksum after >>>> copy >>> operation :-/ >> >> Great! Can you please try to collect level 1 log files with >> the patch https://bugzilla.samba.org/attachment.cgi?id=15955 >> applied? > > I have attached three log files. > log.io_uring.smbd -- Copy using Windows explorer > log.io_uring-mget.smd -- Copy using smbclient > log.io_uring-powershell.smd -- Copy using `Copy-Item` Thanks! All of them show short reads like: > [2020/05/06 17:27:28.130248, 1] ../../source3/modules/vfs_io_uring.c:103(vfs_io_uring_finish_req) > vfs_io_uring_finish_req: pread ofs=0 (0x0) len=32768 (0x8000) nread=32768 (0x32768) eof=10000000 (0x989680) blks=4096 blocks=19536 dir/1.bin fnum 1607026405 > [2020/05/06 17:27:28.131049, 1] ../../source3/modules/vfs_io_uring.c:103(vfs_io_uring_finish_req) > vfs_io_uring_finish_req: pread ofs=9969664 (0x982000) len=30336 (0x7680) nread=30336 (0x30336) eof=10000000 (0x989680) blks=4096 blocks=19536 dir/1.bin fnum 1607026405 > [2020/05/06 17:27:28.133679, 1] ../../source3/modules/vfs_io_uring.c:103(vfs_io_uring_finish_req) > vfs_io_uring_finish_req: pread ofs=61440 (0xf000) len=32768 (0x8000) nread=32768 (0x32768) eof=10000000 (0x989680) blks=4096 blocks=19536 dir/1.bin fnum 1607026405 > [2020/05/06 17:27:28.140184, 0] ../../source3/modules/vfs_io_uring.c:88(vfs_io_uring_finish_req) > vfs_io_uring_finish_req: Invalid pread ofs=0 (0x0) len=1048576 (0x100000) nread=32768 (0x32768) eof=10000000 (0x989680) blks=4096 blocks=19536 dir/1.bin fnum 1607026405 It seems the first request is at ofs=0 len=32768 (0x8000) and we get 32768 back. A follow up request with ofs=0 len=1048576 (0x100000) only gets the first 32768 bytes which are already in the page cache. I can easily reproduce this with the Ubuntu 5.4 kernel once I add state->ur.sqe.rw_flags |= RWF_NOWAIT; to vfs_io_uring_pread_send() and use this. echo 1 > /proc/sys/vm/drop_caches head -c 1024 /root/samba-test/ff1.dat | hexdump -C 00000000 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| * 00000400 smbclient //172.31.9.167/uringff -Uroot%test -c "get ff1.dat" results in this log entries: > [2020/05/06 06:51:57.069990, 0] ../../source3/modules/vfs_io_uring.c:89(vfs_io_uring_finish_req) > vfs_io_uring_finish_req: Invalid pread ofs=0 (0x0) len=8388608 (0x800000) nread=16384 (0x4000) eof=8388608 (0x800000) blks=4096 blocks=16384 ff1.dat fnum 840153065 > [2020/05/06 06:51:57.076882, 1] ../../source3/modules/vfs_io_uring.c:104(vfs_io_uring_finish_req) > vfs_io_uring_finish_req: pread ofs=16384 (0x4000) len=8372224 (0x7fc000) nread=8372224 (0x7fc000) eof=8388608 (0x800000) blks=4096 blocks=16384 ff1.dat fnum 840153065 smbclient is just smart enough to recover itself from the short read. But the windows client isn't. The attached test against liburing (git://git.kernel.dk/liburing) should be able to demonstrate the problem. It can also be found in https://github.com/metze-samba/liburing/tree/implicit-rwf-nowaithttps://github.com/metze-samba/liburing/commit/eb06dcfde747e46bd08bedf9def2e6cb536c39e3 I added the sqe->rw_flags = RWF_NOWAIT; line in order to demonstrate it against the Ubuntu 5.3 and 5.4 kernels. They both seem to have the bug. Can someone run the unmodified test/implicit-rwf_nowait against a newer kernel? Thanks! metze