From 2da22da573481cc4837e246d0eee4d518b3f715e Mon Sep 17 00:00:00 2001 From: Mike Christie Date: Tue, 13 Aug 2019 11:39:52 -0500 Subject: nbd: fix zero cmd timeout handling v2 This fixes a regression added in 4.9 with commit: commit 0eadf37afc2500e1162c9040ec26a705b9af8d47 Author: Josef Bacik Date: Thu Sep 8 12:33:40 2016 -0700 nbd: allow block mq to deal with timeouts where before the patch userspace would set the timeout to 0 to disable it. With the above patch, a zero timeout tells the block layer to use the default value of 30 seconds. For setups where commands can take a long time or experience transient issues like network disruptions this then results in IO errors being sent to the application. To fix this, the patch still uses the common block layer timeout framework, but if zero is set, nbd just logs a message and then resets the timer when it expires. Reviewed-by: Josef Bacik Signed-off-by: Mike Christie Signed-off-by: Jens Axboe --- drivers/block/nbd.c | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-) (limited to 'drivers/block') diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index ebc98cf76365..98c618e5732c 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -121,6 +121,7 @@ struct nbd_cmd { struct mutex lock; int index; int cookie; + int retries; blk_status_t status; unsigned long flags; u32 cmd_cookie; @@ -407,10 +408,25 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req, nbd_config_put(nbd); return BLK_EH_DONE; } - } else { - dev_err_ratelimited(nbd_to_dev(nbd), - "Connection timed out\n"); } + + if (!nbd->tag_set.timeout) { + /* + * Userspace sets timeout=0 to disable socket disconnection, + * so just warn and reset the timer. + */ + cmd->retries++; + dev_info(nbd_to_dev(nbd), "Possible stuck request %p: control (%s@%llu,%uB). Runtime %u seconds\n", + req, nbdcmd_to_ascii(req_to_nbd_cmd_type(req)), + (unsigned long long)blk_rq_pos(req) << 9, + blk_rq_bytes(req), (req->timeout / HZ) * cmd->retries); + + mutex_unlock(&cmd->lock); + nbd_config_put(nbd); + return BLK_EH_RESET_TIMER; + } + + dev_err_ratelimited(nbd_to_dev(nbd), "Connection timed out\n"); set_bit(NBD_TIMEDOUT, &config->runtime_flags); cmd->status = BLK_STS_IOERR; mutex_unlock(&cmd->lock); @@ -531,6 +547,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) } cmd->index = index; cmd->cookie = nsock->cookie; + cmd->retries = 0; request.type = htonl(type | nbd_cmd_flags); if (type != NBD_CMD_FLUSH) { request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); @@ -1254,7 +1271,8 @@ static bool nbd_is_valid_blksize(unsigned long blksize) static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout) { nbd->tag_set.timeout = timeout * HZ; - blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ); + if (timeout) + blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ); } /* Must be called with config_lock held */ @@ -1287,8 +1305,7 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, nbd_size_set(nbd, config->blksize, arg); return 0; case NBD_SET_TIMEOUT: - if (arg) - nbd_set_cmd_timeout(nbd, arg); + nbd_set_cmd_timeout(nbd, arg); return 0; case NBD_SET_FLAGS: -- cgit v1.2.3