On 7/26/21 10:07 AM, Jens Axboe wrote: > On 7/24/21 1:51 PM, Forza wrote: >> >> >> On 2021-07-24 21:44, Jens Axboe wrote: >>> On 7/24/21 12:23 PM, Forza wrote: >>>> Hi! >>>> >>>> On 2021-07-24 19:04, Jens Axboe wrote: >>>>> I'll see if I can reproduce this. I'm assuming samba is using buffered >>>>> IO, and it looks like it's reading in chunks of 1MB. Hopefully it's >>>>> possible to reproduce without samba with a windows client, as I don't >>>>> have any of those. If synthetic reproducing fails, I can try samba >>>>> with a Linux client. >>>> >>>> I attached the logs from both a Windows 10 client and a Linux client >>>> (kernel 5.11.0). >>>> >>>> https://paste.tnonline.net/files/r4yebSzlGEVD_linux-client.txt >>>> >>>> smbd_smb2_read: fnum 2641229669, file >>>> media/vm/libvirt/images/Mint_Cinnamon.img, length=4194304 >>>> offset=736100352 read=4194304 >>>> [2021/07/24 17:26:09.120779, 3] >>>> ../../source3/smbd/smb2_read.c:415(smb2_read_complete) >>>> smbd_smb2_read: fnum 2641229669, file >>>> media/vm/libvirt/images/Mint_Cinnamon.img, length=4194304 >>>> offset=740294656 read=4194304 >>>> [2021/07/24 17:26:09.226593, 3] >>>> ../../source3/smbd/smb2_read.c:415(smb2_read_complete) >>>> smbd_smb2_read: fnum 2641229669, file >>>> media/vm/libvirt/images/Mint_Cinnamon.img, length=4194304 >>>> offset=748683264 read=4194304 >>> >>> Thanks, this is useful. Before I try and reproduce it, what is the >>> filesystem that is hosting the samba mount? >>> >> >> I am using Btrfs. >> >> My testing was done by exporting the share with >> >> vfs objects = io_uring >> vfs objects = btrfs, io_uring >> >> Same results in both cases. Exporting with "vfs objects = btrfs" (no >> io_uring) works as expected. > > Seems to be specific to btrfs, I can reproduce it here. I'll dive in > and see what I can find. This looks like a race in dealing with the task_work running. At least this on top of current -git closes the gap for me and I can't reproduce it anymore. diff --git a/fs/io_uring.c b/fs/io_uring.c index c4d2b320cdd4..998a01cbc00f 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1959,9 +1959,13 @@ static void tctx_task_work(struct callback_head *cb) node = next; } if (wq_list_empty(&tctx->task_list)) { + spin_lock_irq(&tctx->task_lock); clear_bit(0, &tctx->task_state); - if (wq_list_empty(&tctx->task_list)) + if (wq_list_empty(&tctx->task_list)) { + spin_unlock_irq(&tctx->task_lock); break; + } + spin_unlock_irq(&tctx->task_lock); /* another tctx_task_work() is enqueued, yield */ if (test_and_set_bit(0, &tctx->task_state)) break; -- Jens Axboe
