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path: root/drivers/block/nbd.c
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Diffstat (limited to 'drivers/block/nbd.c')
-rw-r--r--drivers/block/nbd.c96
1 files changed, 79 insertions, 17 deletions
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index e07401d3901d..3863c00372bb 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -112,12 +112,16 @@ struct nbd_device {
struct task_struct *task_setup;
};
+#define NBD_CMD_REQUEUED 1
+
struct nbd_cmd {
struct nbd_device *nbd;
+ struct mutex lock;
int index;
int cookie;
- struct completion send_complete;
blk_status_t status;
+ unsigned long flags;
+ u32 cmd_cookie;
};
#if IS_ENABLED(CONFIG_DEBUG_FS)
@@ -146,6 +150,35 @@ static inline struct device *nbd_to_dev(struct nbd_device *nbd)
return disk_to_dev(nbd->disk);
}
+static void nbd_requeue_cmd(struct nbd_cmd *cmd)
+{
+ struct request *req = blk_mq_rq_from_pdu(cmd);
+
+ if (!test_and_set_bit(NBD_CMD_REQUEUED, &cmd->flags))
+ blk_mq_requeue_request(req, true);
+}
+
+#define NBD_COOKIE_BITS 32
+
+static u64 nbd_cmd_handle(struct nbd_cmd *cmd)
+{
+ struct request *req = blk_mq_rq_from_pdu(cmd);
+ u32 tag = blk_mq_unique_tag(req);
+ u64 cookie = cmd->cmd_cookie;
+
+ return (cookie << NBD_COOKIE_BITS) | tag;
+}
+
+static u32 nbd_handle_to_tag(u64 handle)
+{
+ return (u32)handle;
+}
+
+static u32 nbd_handle_to_cookie(u64 handle)
+{
+ return (u32)(handle >> NBD_COOKIE_BITS);
+}
+
static const char *nbdcmd_to_ascii(int cmd)
{
switch (cmd) {
@@ -319,6 +352,9 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
}
config = nbd->config;
+ if (!mutex_trylock(&cmd->lock))
+ return BLK_EH_RESET_TIMER;
+
if (config->num_connections > 1) {
dev_err_ratelimited(nbd_to_dev(nbd),
"Connection timed out, retrying (%d/%d alive)\n",
@@ -343,7 +379,8 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
nbd_mark_nsock_dead(nbd, nsock, 1);
mutex_unlock(&nsock->tx_lock);
}
- blk_mq_requeue_request(req, true);
+ mutex_unlock(&cmd->lock);
+ nbd_requeue_cmd(cmd);
nbd_config_put(nbd);
return BLK_EH_DONE;
}
@@ -353,6 +390,7 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
}
set_bit(NBD_TIMEDOUT, &config->runtime_flags);
cmd->status = BLK_STS_IOERR;
+ mutex_unlock(&cmd->lock);
sock_shutdown(nbd);
nbd_config_put(nbd);
done:
@@ -430,9 +468,9 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
struct iov_iter from;
unsigned long size = blk_rq_bytes(req);
struct bio *bio;
+ u64 handle;
u32 type;
u32 nbd_cmd_flags = 0;
- u32 tag = blk_mq_unique_tag(req);
int sent = nsock->sent, skip = 0;
iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));
@@ -474,6 +512,8 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
goto send_pages;
}
iov_iter_advance(&from, sent);
+ } else {
+ cmd->cmd_cookie++;
}
cmd->index = index;
cmd->cookie = nsock->cookie;
@@ -482,7 +522,8 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
request.len = htonl(size);
}
- memcpy(request.handle, &tag, sizeof(tag));
+ handle = nbd_cmd_handle(cmd);
+ memcpy(request.handle, &handle, sizeof(handle));
dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
req, nbdcmd_to_ascii(type),
@@ -500,6 +541,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
nsock->pending = req;
nsock->sent = sent;
}
+ set_bit(NBD_CMD_REQUEUED, &cmd->flags);
return BLK_STS_RESOURCE;
}
dev_err_ratelimited(disk_to_dev(nbd->disk),
@@ -541,6 +583,7 @@ send_pages:
*/
nsock->pending = req;
nsock->sent = sent;
+ set_bit(NBD_CMD_REQUEUED, &cmd->flags);
return BLK_STS_RESOURCE;
}
dev_err(disk_to_dev(nbd->disk),
@@ -573,10 +616,12 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
struct nbd_reply reply;
struct nbd_cmd *cmd;
struct request *req = NULL;
+ u64 handle;
u16 hwq;
u32 tag;
struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)};
struct iov_iter to;
+ int ret = 0;
reply.magic = 0;
iov_iter_kvec(&to, READ | ITER_KVEC, &iov, 1, sizeof(reply));
@@ -594,8 +639,8 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
return ERR_PTR(-EPROTO);
}
- memcpy(&tag, reply.handle, sizeof(u32));
-
+ memcpy(&handle, reply.handle, sizeof(handle));
+ tag = nbd_handle_to_tag(handle);
hwq = blk_mq_unique_tag_to_hwq(tag);
if (hwq < nbd->tag_set.nr_hw_queues)
req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
@@ -606,11 +651,25 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
return ERR_PTR(-ENOENT);
}
cmd = blk_mq_rq_to_pdu(req);
+
+ mutex_lock(&cmd->lock);
+ if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) {
+ dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n",
+ req, cmd->cmd_cookie, nbd_handle_to_cookie(handle));
+ ret = -ENOENT;
+ goto out;
+ }
+ if (test_bit(NBD_CMD_REQUEUED, &cmd->flags)) {
+ dev_err(disk_to_dev(nbd->disk), "Raced with timeout on req %p\n",
+ req);
+ ret = -ENOENT;
+ goto out;
+ }
if (ntohl(reply.error)) {
dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
ntohl(reply.error));
cmd->status = BLK_STS_IOERR;
- return cmd;
+ goto out;
}
dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req);
@@ -635,18 +694,18 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
if (nbd_disconnected(config) ||
config->num_connections <= 1) {
cmd->status = BLK_STS_IOERR;
- return cmd;
+ goto out;
}
- return ERR_PTR(-EIO);
+ ret = -EIO;
+ goto out;
}
dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
req, bvec.bv_len);
}
- } else {
- /* See the comment in nbd_queue_rq. */
- wait_for_completion(&cmd->send_complete);
}
- return cmd;
+out:
+ mutex_unlock(&cmd->lock);
+ return ret ? ERR_PTR(ret) : cmd;
}
static void recv_work(struct work_struct *work)
@@ -805,7 +864,7 @@ again:
*/
blk_mq_start_request(req);
if (unlikely(nsock->pending && nsock->pending != req)) {
- blk_mq_requeue_request(req, true);
+ nbd_requeue_cmd(cmd);
ret = 0;
goto out;
}
@@ -818,7 +877,7 @@ again:
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Request send failed, requeueing\n");
nbd_mark_nsock_dead(nbd, nsock, 1);
- blk_mq_requeue_request(req, true);
+ nbd_requeue_cmd(cmd);
ret = 0;
}
out:
@@ -842,7 +901,8 @@ static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
* that the server is misbehaving (or there was an error) before we're
* done sending everything over the wire.
*/
- init_completion(&cmd->send_complete);
+ mutex_lock(&cmd->lock);
+ clear_bit(NBD_CMD_REQUEUED, &cmd->flags);
/* We can be called directly from the user space process, which means we
* could possibly have signals pending so our sendmsg will fail. In
@@ -854,7 +914,7 @@ static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
ret = BLK_STS_IOERR;
else if (!ret)
ret = BLK_STS_OK;
- complete(&cmd->send_complete);
+ mutex_unlock(&cmd->lock);
return ret;
}
@@ -1460,6 +1520,8 @@ static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
{
struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
cmd->nbd = set->driver_data;
+ cmd->flags = 0;
+ mutex_init(&cmd->lock);
return 0;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-11 19:32:24 +0000