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author | Fabian Ebner <f.ebner@proxmox.com> | 2021-07-29 11:10:29 +0200 |
---|---|---|
committer | Stefan Hajnoczi <stefanha@redhat.com> | 2021-07-29 17:14:55 +0100 |
commit | 54caccb3657e3960d8f5d57ab8e867028325d131 (patch) | |
tree | ee24f233b3afb6d9d5bb2afd304f49c6196defb7 /block/io_uring.c | |
parent | 0ef2801423be33d80b52b14b6b55b3713a325dba (diff) | |
download | qemu-54caccb3657e3960d8f5d57ab8e867028325d131.zip qemu-54caccb3657e3960d8f5d57ab8e867028325d131.tar.gz qemu-54caccb3657e3960d8f5d57ab8e867028325d131.tar.bz2 |
block/io_uring: resubmit when result is -EAGAIN
Linux SCSI can throw spurious -EAGAIN in some corner cases in its
completion path, which will end up being the result in the completed
io_uring request.
Resubmitting such requests should allow block jobs to complete, even
if such spurious errors are encountered.
Co-authored-by: Stefan Hajnoczi <stefanha@gmail.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
Message-id: 20210729091029.65369-1-f.ebner@proxmox.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block/io_uring.c')
-rw-r--r-- | block/io_uring.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/block/io_uring.c b/block/io_uring.c index 00a3ee9..dfa475c 100644 --- a/block/io_uring.c +++ b/block/io_uring.c @@ -165,7 +165,21 @@ static void luring_process_completions(LuringState *s) total_bytes = ret + luringcb->total_read; if (ret < 0) { - if (ret == -EINTR) { + /* + * Only writev/readv/fsync requests on regular files or host block + * devices are submitted. Therefore -EAGAIN is not expected but it's + * known to happen sometimes with Linux SCSI. Submit again and hope + * the request completes successfully. + * + * For more information, see: + * https://lore.kernel.org/io-uring/20210727165811.284510-3-axboe@kernel.dk/T/#u + * + * If the code is changed to submit other types of requests in the + * future, then this workaround may need to be extended to deal with + * genuine -EAGAIN results that should not be resubmitted + * immediately. + */ + if (ret == -EINTR || ret == -EAGAIN) { luring_resubmit(s, luringcb); continue; } |