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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /drivers/block/nbd.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/block/nbd.c')
-rw-r--r--drivers/block/nbd.c2630
1 files changed, 2630 insertions, 0 deletions
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
new file mode 100644
index 0000000000..aa65313aab
--- /dev/null
+++ b/drivers/block/nbd.c
@@ -0,0 +1,2630 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Network block device - make block devices work over TCP
+ *
+ * Note that you can not swap over this thing, yet. Seems to work but
+ * deadlocks sometimes - you can not swap over TCP in general.
+ *
+ * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
+ * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
+ *
+ * (part of code stolen from loop.c)
+ */
+
+#define pr_fmt(fmt) "nbd: " fmt
+
+#include <linux/major.h>
+
+#include <linux/blkdev.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/sched/mm.h>
+#include <linux/fs.h>
+#include <linux/bio.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/file.h>
+#include <linux/ioctl.h>
+#include <linux/mutex.h>
+#include <linux/compiler.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <net/sock.h>
+#include <linux/net.h>
+#include <linux/kthread.h>
+#include <linux/types.h>
+#include <linux/debugfs.h>
+#include <linux/blk-mq.h>
+
+#include <linux/uaccess.h>
+#include <asm/types.h>
+
+#include <linux/nbd.h>
+#include <linux/nbd-netlink.h>
+#include <net/genetlink.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/nbd.h>
+
+static DEFINE_IDR(nbd_index_idr);
+static DEFINE_MUTEX(nbd_index_mutex);
+static struct workqueue_struct *nbd_del_wq;
+static int nbd_total_devices = 0;
+
+struct nbd_sock {
+ struct socket *sock;
+ struct mutex tx_lock;
+ struct request *pending;
+ int sent;
+ bool dead;
+ int fallback_index;
+ int cookie;
+};
+
+struct recv_thread_args {
+ struct work_struct work;
+ struct nbd_device *nbd;
+ struct nbd_sock *nsock;
+ int index;
+};
+
+struct link_dead_args {
+ struct work_struct work;
+ int index;
+};
+
+#define NBD_RT_TIMEDOUT 0
+#define NBD_RT_DISCONNECT_REQUESTED 1
+#define NBD_RT_DISCONNECTED 2
+#define NBD_RT_HAS_PID_FILE 3
+#define NBD_RT_HAS_CONFIG_REF 4
+#define NBD_RT_BOUND 5
+#define NBD_RT_DISCONNECT_ON_CLOSE 6
+#define NBD_RT_HAS_BACKEND_FILE 7
+
+#define NBD_DESTROY_ON_DISCONNECT 0
+#define NBD_DISCONNECT_REQUESTED 1
+
+struct nbd_config {
+ u32 flags;
+ unsigned long runtime_flags;
+ u64 dead_conn_timeout;
+
+ struct nbd_sock **socks;
+ int num_connections;
+ atomic_t live_connections;
+ wait_queue_head_t conn_wait;
+
+ atomic_t recv_threads;
+ wait_queue_head_t recv_wq;
+ unsigned int blksize_bits;
+ loff_t bytesize;
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+ struct dentry *dbg_dir;
+#endif
+};
+
+static inline unsigned int nbd_blksize(struct nbd_config *config)
+{
+ return 1u << config->blksize_bits;
+}
+
+struct nbd_device {
+ struct blk_mq_tag_set tag_set;
+
+ int index;
+ refcount_t config_refs;
+ refcount_t refs;
+ struct nbd_config *config;
+ struct mutex config_lock;
+ struct gendisk *disk;
+ struct workqueue_struct *recv_workq;
+ struct work_struct remove_work;
+
+ struct list_head list;
+ struct task_struct *task_setup;
+
+ unsigned long flags;
+ pid_t pid; /* pid of nbd-client, if attached */
+
+ char *backend;
+};
+
+#define NBD_CMD_REQUEUED 1
+/*
+ * This flag will be set if nbd_queue_rq() succeed, and will be checked and
+ * cleared in completion. Both setting and clearing of the flag are protected
+ * by cmd->lock.
+ */
+#define NBD_CMD_INFLIGHT 2
+
+struct nbd_cmd {
+ struct nbd_device *nbd;
+ struct mutex lock;
+ int index;
+ int cookie;
+ int retries;
+ blk_status_t status;
+ unsigned long flags;
+ u32 cmd_cookie;
+};
+
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+static struct dentry *nbd_dbg_dir;
+#endif
+
+#define nbd_name(nbd) ((nbd)->disk->disk_name)
+
+#define NBD_DEF_BLKSIZE_BITS 10
+
+static unsigned int nbds_max = 16;
+static int max_part = 16;
+static int part_shift;
+
+static int nbd_dev_dbg_init(struct nbd_device *nbd);
+static void nbd_dev_dbg_close(struct nbd_device *nbd);
+static void nbd_config_put(struct nbd_device *nbd);
+static void nbd_connect_reply(struct genl_info *info, int index);
+static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info);
+static void nbd_dead_link_work(struct work_struct *work);
+static void nbd_disconnect_and_put(struct nbd_device *nbd);
+
+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) {
+ case NBD_CMD_READ: return "read";
+ case NBD_CMD_WRITE: return "write";
+ case NBD_CMD_DISC: return "disconnect";
+ case NBD_CMD_FLUSH: return "flush";
+ case NBD_CMD_TRIM: return "trim/discard";
+ }
+ return "invalid";
+}
+
+static ssize_t pid_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+ struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
+
+ return sprintf(buf, "%d\n", nbd->pid);
+}
+
+static const struct device_attribute pid_attr = {
+ .attr = { .name = "pid", .mode = 0444},
+ .show = pid_show,
+};
+
+static ssize_t backend_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct gendisk *disk = dev_to_disk(dev);
+ struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
+
+ return sprintf(buf, "%s\n", nbd->backend ?: "");
+}
+
+static const struct device_attribute backend_attr = {
+ .attr = { .name = "backend", .mode = 0444},
+ .show = backend_show,
+};
+
+static void nbd_dev_remove(struct nbd_device *nbd)
+{
+ struct gendisk *disk = nbd->disk;
+
+ del_gendisk(disk);
+ blk_mq_free_tag_set(&nbd->tag_set);
+
+ /*
+ * Remove from idr after del_gendisk() completes, so if the same ID is
+ * reused, the following add_disk() will succeed.
+ */
+ mutex_lock(&nbd_index_mutex);
+ idr_remove(&nbd_index_idr, nbd->index);
+ mutex_unlock(&nbd_index_mutex);
+ destroy_workqueue(nbd->recv_workq);
+ put_disk(disk);
+}
+
+static void nbd_dev_remove_work(struct work_struct *work)
+{
+ nbd_dev_remove(container_of(work, struct nbd_device, remove_work));
+}
+
+static void nbd_put(struct nbd_device *nbd)
+{
+ if (!refcount_dec_and_test(&nbd->refs))
+ return;
+
+ /* Call del_gendisk() asynchrounously to prevent deadlock */
+ if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags))
+ queue_work(nbd_del_wq, &nbd->remove_work);
+ else
+ nbd_dev_remove(nbd);
+}
+
+static int nbd_disconnected(struct nbd_config *config)
+{
+ return test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags) ||
+ test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
+}
+
+static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
+ int notify)
+{
+ if (!nsock->dead && notify && !nbd_disconnected(nbd->config)) {
+ struct link_dead_args *args;
+ args = kmalloc(sizeof(struct link_dead_args), GFP_NOIO);
+ if (args) {
+ INIT_WORK(&args->work, nbd_dead_link_work);
+ args->index = nbd->index;
+ queue_work(system_wq, &args->work);
+ }
+ }
+ if (!nsock->dead) {
+ kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
+ if (atomic_dec_return(&nbd->config->live_connections) == 0) {
+ if (test_and_clear_bit(NBD_RT_DISCONNECT_REQUESTED,
+ &nbd->config->runtime_flags)) {
+ set_bit(NBD_RT_DISCONNECTED,
+ &nbd->config->runtime_flags);
+ dev_info(nbd_to_dev(nbd),
+ "Disconnected due to user request.\n");
+ }
+ }
+ }
+ nsock->dead = true;
+ nsock->pending = NULL;
+ nsock->sent = 0;
+}
+
+static int nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
+ loff_t blksize)
+{
+ if (!blksize)
+ blksize = 1u << NBD_DEF_BLKSIZE_BITS;
+
+ if (blk_validate_block_size(blksize))
+ return -EINVAL;
+
+ if (bytesize < 0)
+ return -EINVAL;
+
+ nbd->config->bytesize = bytesize;
+ nbd->config->blksize_bits = __ffs(blksize);
+
+ if (!nbd->pid)
+ return 0;
+
+ if (nbd->config->flags & NBD_FLAG_SEND_TRIM) {
+ nbd->disk->queue->limits.discard_granularity = blksize;
+ blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
+ }
+ blk_queue_logical_block_size(nbd->disk->queue, blksize);
+ blk_queue_physical_block_size(nbd->disk->queue, blksize);
+
+ if (max_part)
+ set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
+ if (!set_capacity_and_notify(nbd->disk, bytesize >> 9))
+ kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
+ return 0;
+}
+
+static void nbd_complete_rq(struct request *req)
+{
+ struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
+
+ dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", req,
+ cmd->status ? "failed" : "done");
+
+ blk_mq_end_request(req, cmd->status);
+}
+
+/*
+ * Forcibly shutdown the socket causing all listeners to error
+ */
+static void sock_shutdown(struct nbd_device *nbd)
+{
+ struct nbd_config *config = nbd->config;
+ int i;
+
+ if (config->num_connections == 0)
+ return;
+ if (test_and_set_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
+ return;
+
+ for (i = 0; i < config->num_connections; i++) {
+ struct nbd_sock *nsock = config->socks[i];
+ mutex_lock(&nsock->tx_lock);
+ nbd_mark_nsock_dead(nbd, nsock, 0);
+ mutex_unlock(&nsock->tx_lock);
+ }
+ dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
+}
+
+static u32 req_to_nbd_cmd_type(struct request *req)
+{
+ switch (req_op(req)) {
+ case REQ_OP_DISCARD:
+ return NBD_CMD_TRIM;
+ case REQ_OP_FLUSH:
+ return NBD_CMD_FLUSH;
+ case REQ_OP_WRITE:
+ return NBD_CMD_WRITE;
+ case REQ_OP_READ:
+ return NBD_CMD_READ;
+ default:
+ return U32_MAX;
+ }
+}
+
+static struct nbd_config *nbd_get_config_unlocked(struct nbd_device *nbd)
+{
+ if (refcount_inc_not_zero(&nbd->config_refs)) {
+ /*
+ * Add smp_mb__after_atomic to ensure that reading nbd->config_refs
+ * and reading nbd->config is ordered. The pair is the barrier in
+ * nbd_alloc_and_init_config(), avoid nbd->config_refs is set
+ * before nbd->config.
+ */
+ smp_mb__after_atomic();
+ return nbd->config;
+ }
+
+ return NULL;
+}
+
+static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req)
+{
+ struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
+ struct nbd_device *nbd = cmd->nbd;
+ struct nbd_config *config;
+
+ if (!mutex_trylock(&cmd->lock))
+ return BLK_EH_RESET_TIMER;
+
+ if (!test_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
+ mutex_unlock(&cmd->lock);
+ return BLK_EH_DONE;
+ }
+
+ config = nbd_get_config_unlocked(nbd);
+ if (!config) {
+ cmd->status = BLK_STS_TIMEOUT;
+ __clear_bit(NBD_CMD_INFLIGHT, &cmd->flags);
+ mutex_unlock(&cmd->lock);
+ goto done;
+ }
+
+ if (config->num_connections > 1 ||
+ (config->num_connections == 1 && nbd->tag_set.timeout)) {
+ dev_err_ratelimited(nbd_to_dev(nbd),
+ "Connection timed out, retrying (%d/%d alive)\n",
+ atomic_read(&config->live_connections),
+ config->num_connections);
+ /*
+ * Hooray we have more connections, requeue this IO, the submit
+ * path will put it on a real connection. Or if only one
+ * connection is configured, the submit path will wait util
+ * a new connection is reconfigured or util dead timeout.
+ */
+ if (config->socks) {
+ if (cmd->index < config->num_connections) {
+ struct nbd_sock *nsock =
+ config->socks[cmd->index];
+ mutex_lock(&nsock->tx_lock);
+ /* We can have multiple outstanding requests, so
+ * we don't want to mark the nsock dead if we've
+ * already reconnected with a new socket, so
+ * only mark it dead if its the same socket we
+ * were sent out on.
+ */
+ if (cmd->cookie == nsock->cookie)
+ nbd_mark_nsock_dead(nbd, nsock, 1);
+ mutex_unlock(&nsock->tx_lock);
+ }
+ mutex_unlock(&cmd->lock);
+ nbd_requeue_cmd(cmd);
+ nbd_config_put(nbd);
+ return BLK_EH_DONE;
+ }
+ }
+
+ if (!nbd->tag_set.timeout) {
+ /*
+ * Userspace sets timeout=0 to disable socket disconnection,
+ * so just warn and reset the timer.
+ */
+ struct nbd_sock *nsock = config->socks[cmd->index];
+ 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_lock(&nsock->tx_lock);
+ if (cmd->cookie != nsock->cookie) {
+ nbd_requeue_cmd(cmd);
+ mutex_unlock(&nsock->tx_lock);
+ mutex_unlock(&cmd->lock);
+ nbd_config_put(nbd);
+ return BLK_EH_DONE;
+ }
+ mutex_unlock(&nsock->tx_lock);
+ 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_RT_TIMEDOUT, &config->runtime_flags);
+ cmd->status = BLK_STS_IOERR;
+ __clear_bit(NBD_CMD_INFLIGHT, &cmd->flags);
+ mutex_unlock(&cmd->lock);
+ sock_shutdown(nbd);
+ nbd_config_put(nbd);
+done:
+ blk_mq_complete_request(req);
+ return BLK_EH_DONE;
+}
+
+static int __sock_xmit(struct nbd_device *nbd, struct socket *sock, int send,
+ struct iov_iter *iter, int msg_flags, int *sent)
+{
+ int result;
+ struct msghdr msg = {} ;
+ unsigned int noreclaim_flag;
+
+ if (unlikely(!sock)) {
+ dev_err_ratelimited(disk_to_dev(nbd->disk),
+ "Attempted %s on closed socket in sock_xmit\n",
+ (send ? "send" : "recv"));
+ return -EINVAL;
+ }
+
+ msg.msg_iter = *iter;
+
+ noreclaim_flag = memalloc_noreclaim_save();
+ do {
+ sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
+ sock->sk->sk_use_task_frag = false;
+ msg.msg_flags = msg_flags | MSG_NOSIGNAL;
+
+ if (send)
+ result = sock_sendmsg(sock, &msg);
+ else
+ result = sock_recvmsg(sock, &msg, msg.msg_flags);
+
+ if (result <= 0) {
+ if (result == 0)
+ result = -EPIPE; /* short read */
+ break;
+ }
+ if (sent)
+ *sent += result;
+ } while (msg_data_left(&msg));
+
+ memalloc_noreclaim_restore(noreclaim_flag);
+
+ return result;
+}
+
+/*
+ * Send or receive packet. Return a positive value on success and
+ * negtive value on failure, and never return 0.
+ */
+static int sock_xmit(struct nbd_device *nbd, int index, int send,
+ struct iov_iter *iter, int msg_flags, int *sent)
+{
+ struct nbd_config *config = nbd->config;
+ struct socket *sock = config->socks[index]->sock;
+
+ return __sock_xmit(nbd, sock, send, iter, msg_flags, sent);
+}
+
+/*
+ * Different settings for sk->sk_sndtimeo can result in different return values
+ * if there is a signal pending when we enter sendmsg, because reasons?
+ */
+static inline int was_interrupted(int result)
+{
+ return result == -ERESTARTSYS || result == -EINTR;
+}
+
+/* always call with the tx_lock held */
+static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
+{
+ struct request *req = blk_mq_rq_from_pdu(cmd);
+ struct nbd_config *config = nbd->config;
+ struct nbd_sock *nsock = config->socks[index];
+ int result;
+ struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
+ struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
+ struct iov_iter from;
+ unsigned long size = blk_rq_bytes(req);
+ struct bio *bio;
+ u64 handle;
+ u32 type;
+ u32 nbd_cmd_flags = 0;
+ int sent = nsock->sent, skip = 0;
+
+ iov_iter_kvec(&from, ITER_SOURCE, &iov, 1, sizeof(request));
+
+ type = req_to_nbd_cmd_type(req);
+ if (type == U32_MAX)
+ return -EIO;
+
+ if (rq_data_dir(req) == WRITE &&
+ (config->flags & NBD_FLAG_READ_ONLY)) {
+ dev_err_ratelimited(disk_to_dev(nbd->disk),
+ "Write on read-only\n");
+ return -EIO;
+ }
+
+ if (req->cmd_flags & REQ_FUA)
+ nbd_cmd_flags |= NBD_CMD_FLAG_FUA;
+
+ /* We did a partial send previously, and we at least sent the whole
+ * request struct, so just go and send the rest of the pages in the
+ * request.
+ */
+ if (sent) {
+ if (sent >= sizeof(request)) {
+ skip = sent - sizeof(request);
+
+ /* initialize handle for tracing purposes */
+ handle = nbd_cmd_handle(cmd);
+
+ goto send_pages;
+ }
+ iov_iter_advance(&from, sent);
+ } else {
+ cmd->cmd_cookie++;
+ }
+ 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);
+ request.len = htonl(size);
+ }
+ handle = nbd_cmd_handle(cmd);
+ request.cookie = cpu_to_be64(handle);
+
+ trace_nbd_send_request(&request, nbd->index, blk_mq_rq_from_pdu(cmd));
+
+ dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
+ req, nbdcmd_to_ascii(type),
+ (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
+ result = sock_xmit(nbd, index, 1, &from,
+ (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
+ trace_nbd_header_sent(req, handle);
+ if (result < 0) {
+ if (was_interrupted(result)) {
+ /* If we haven't sent anything we can just return BUSY,
+ * however if we have sent something we need to make
+ * sure we only allow this req to be sent until we are
+ * completely done.
+ */
+ if (sent) {
+ 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),
+ "Send control failed (result %d)\n", result);
+ return -EAGAIN;
+ }
+send_pages:
+ if (type != NBD_CMD_WRITE)
+ goto out;
+
+ bio = req->bio;
+ while (bio) {
+ struct bio *next = bio->bi_next;
+ struct bvec_iter iter;
+ struct bio_vec bvec;
+
+ bio_for_each_segment(bvec, bio, iter) {
+ bool is_last = !next && bio_iter_last(bvec, iter);
+ int flags = is_last ? 0 : MSG_MORE;
+
+ dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
+ req, bvec.bv_len);
+ iov_iter_bvec(&from, ITER_SOURCE, &bvec, 1, bvec.bv_len);
+ if (skip) {
+ if (skip >= iov_iter_count(&from)) {
+ skip -= iov_iter_count(&from);
+ continue;
+ }
+ iov_iter_advance(&from, skip);
+ skip = 0;
+ }
+ result = sock_xmit(nbd, index, 1, &from, flags, &sent);
+ if (result < 0) {
+ if (was_interrupted(result)) {
+ /* We've already sent the header, we
+ * have no choice but to set pending and
+ * return BUSY.
+ */
+ nsock->pending = req;
+ nsock->sent = sent;
+ set_bit(NBD_CMD_REQUEUED, &cmd->flags);
+ return BLK_STS_RESOURCE;
+ }
+ dev_err(disk_to_dev(nbd->disk),
+ "Send data failed (result %d)\n",
+ result);
+ return -EAGAIN;
+ }
+ /*
+ * The completion might already have come in,
+ * so break for the last one instead of letting
+ * the iterator do it. This prevents use-after-free
+ * of the bio.
+ */
+ if (is_last)
+ break;
+ }
+ bio = next;
+ }
+out:
+ trace_nbd_payload_sent(req, handle);
+ nsock->pending = NULL;
+ nsock->sent = 0;
+ return 0;
+}
+
+static int nbd_read_reply(struct nbd_device *nbd, struct socket *sock,
+ struct nbd_reply *reply)
+{
+ struct kvec iov = {.iov_base = reply, .iov_len = sizeof(*reply)};
+ struct iov_iter to;
+ int result;
+
+ reply->magic = 0;
+ iov_iter_kvec(&to, ITER_DEST, &iov, 1, sizeof(*reply));
+ result = __sock_xmit(nbd, sock, 0, &to, MSG_WAITALL, NULL);
+ if (result < 0) {
+ if (!nbd_disconnected(nbd->config))
+ dev_err(disk_to_dev(nbd->disk),
+ "Receive control failed (result %d)\n", result);
+ return result;
+ }
+
+ if (ntohl(reply->magic) != NBD_REPLY_MAGIC) {
+ dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
+ (unsigned long)ntohl(reply->magic));
+ return -EPROTO;
+ }
+
+ return 0;
+}
+
+/* NULL returned = something went wrong, inform userspace */
+static struct nbd_cmd *nbd_handle_reply(struct nbd_device *nbd, int index,
+ struct nbd_reply *reply)
+{
+ int result;
+ struct nbd_cmd *cmd;
+ struct request *req = NULL;
+ u64 handle;
+ u16 hwq;
+ u32 tag;
+ int ret = 0;
+
+ handle = be64_to_cpu(reply->cookie);
+ 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],
+ blk_mq_unique_tag_to_tag(tag));
+ if (!req || !blk_mq_request_started(req)) {
+ dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
+ tag, req);
+ return ERR_PTR(-ENOENT);
+ }
+ trace_nbd_header_received(req, handle);
+ cmd = blk_mq_rq_to_pdu(req);
+
+ mutex_lock(&cmd->lock);
+ if (!test_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
+ dev_err(disk_to_dev(nbd->disk), "Suspicious reply %d (status %u flags %lu)",
+ tag, cmd->status, cmd->flags);
+ ret = -ENOENT;
+ goto out;
+ }
+ if (cmd->index != index) {
+ dev_err(disk_to_dev(nbd->disk), "Unexpected reply %d from different sock %d (expected %d)",
+ tag, index, cmd->index);
+ ret = -ENOENT;
+ goto out;
+ }
+ 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 (cmd->status != BLK_STS_OK) {
+ dev_err(disk_to_dev(nbd->disk), "Command already handled %p\n",
+ req);
+ 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;
+ goto out;
+ }
+
+ dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req);
+ if (rq_data_dir(req) != WRITE) {
+ struct req_iterator iter;
+ struct bio_vec bvec;
+ struct iov_iter to;
+
+ rq_for_each_segment(bvec, req, iter) {
+ iov_iter_bvec(&to, ITER_DEST, &bvec, 1, bvec.bv_len);
+ result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
+ if (result < 0) {
+ dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
+ result);
+ /*
+ * If we've disconnected, we need to make sure we
+ * complete this request, otherwise error out
+ * and let the timeout stuff handle resubmitting
+ * this request onto another connection.
+ */
+ if (nbd_disconnected(nbd->config)) {
+ cmd->status = BLK_STS_IOERR;
+ goto out;
+ }
+ ret = -EIO;
+ goto out;
+ }
+ dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
+ req, bvec.bv_len);
+ }
+ }
+out:
+ trace_nbd_payload_received(req, handle);
+ mutex_unlock(&cmd->lock);
+ return ret ? ERR_PTR(ret) : cmd;
+}
+
+static void recv_work(struct work_struct *work)
+{
+ struct recv_thread_args *args = container_of(work,
+ struct recv_thread_args,
+ work);
+ struct nbd_device *nbd = args->nbd;
+ struct nbd_config *config = nbd->config;
+ struct request_queue *q = nbd->disk->queue;
+ struct nbd_sock *nsock = args->nsock;
+ struct nbd_cmd *cmd;
+ struct request *rq;
+
+ while (1) {
+ struct nbd_reply reply;
+
+ if (nbd_read_reply(nbd, nsock->sock, &reply))
+ break;
+
+ /*
+ * Grab .q_usage_counter so request pool won't go away, then no
+ * request use-after-free is possible during nbd_handle_reply().
+ * If queue is frozen, there won't be any inflight requests, we
+ * needn't to handle the incoming garbage message.
+ */
+ if (!percpu_ref_tryget(&q->q_usage_counter)) {
+ dev_err(disk_to_dev(nbd->disk), "%s: no io inflight\n",
+ __func__);
+ break;
+ }
+
+ cmd = nbd_handle_reply(nbd, args->index, &reply);
+ if (IS_ERR(cmd)) {
+ percpu_ref_put(&q->q_usage_counter);
+ break;
+ }
+
+ rq = blk_mq_rq_from_pdu(cmd);
+ if (likely(!blk_should_fake_timeout(rq->q))) {
+ bool complete;
+
+ mutex_lock(&cmd->lock);
+ complete = __test_and_clear_bit(NBD_CMD_INFLIGHT,
+ &cmd->flags);
+ mutex_unlock(&cmd->lock);
+ if (complete)
+ blk_mq_complete_request(rq);
+ }
+ percpu_ref_put(&q->q_usage_counter);
+ }
+
+ mutex_lock(&nsock->tx_lock);
+ nbd_mark_nsock_dead(nbd, nsock, 1);
+ mutex_unlock(&nsock->tx_lock);
+
+ nbd_config_put(nbd);
+ atomic_dec(&config->recv_threads);
+ wake_up(&config->recv_wq);
+ kfree(args);
+}
+
+static bool nbd_clear_req(struct request *req, void *data)
+{
+ struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
+
+ /* don't abort one completed request */
+ if (blk_mq_request_completed(req))
+ return true;
+
+ mutex_lock(&cmd->lock);
+ if (!__test_and_clear_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
+ mutex_unlock(&cmd->lock);
+ return true;
+ }
+ cmd->status = BLK_STS_IOERR;
+ mutex_unlock(&cmd->lock);
+
+ blk_mq_complete_request(req);
+ return true;
+}
+
+static void nbd_clear_que(struct nbd_device *nbd)
+{
+ blk_mq_quiesce_queue(nbd->disk->queue);
+ blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
+ blk_mq_unquiesce_queue(nbd->disk->queue);
+ dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
+}
+
+static int find_fallback(struct nbd_device *nbd, int index)
+{
+ struct nbd_config *config = nbd->config;
+ int new_index = -1;
+ struct nbd_sock *nsock = config->socks[index];
+ int fallback = nsock->fallback_index;
+
+ if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
+ return new_index;
+
+ if (config->num_connections <= 1) {
+ dev_err_ratelimited(disk_to_dev(nbd->disk),
+ "Dead connection, failed to find a fallback\n");
+ return new_index;
+ }
+
+ if (fallback >= 0 && fallback < config->num_connections &&
+ !config->socks[fallback]->dead)
+ return fallback;
+
+ if (nsock->fallback_index < 0 ||
+ nsock->fallback_index >= config->num_connections ||
+ config->socks[nsock->fallback_index]->dead) {
+ int i;
+ for (i = 0; i < config->num_connections; i++) {
+ if (i == index)
+ continue;
+ if (!config->socks[i]->dead) {
+ new_index = i;
+ break;
+ }
+ }
+ nsock->fallback_index = new_index;
+ if (new_index < 0) {
+ dev_err_ratelimited(disk_to_dev(nbd->disk),
+ "Dead connection, failed to find a fallback\n");
+ return new_index;
+ }
+ }
+ new_index = nsock->fallback_index;
+ return new_index;
+}
+
+static int wait_for_reconnect(struct nbd_device *nbd)
+{
+ struct nbd_config *config = nbd->config;
+ if (!config->dead_conn_timeout)
+ return 0;
+
+ if (!wait_event_timeout(config->conn_wait,
+ test_bit(NBD_RT_DISCONNECTED,
+ &config->runtime_flags) ||
+ atomic_read(&config->live_connections) > 0,
+ config->dead_conn_timeout))
+ return 0;
+
+ return !test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
+}
+
+static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
+{
+ struct request *req = blk_mq_rq_from_pdu(cmd);
+ struct nbd_device *nbd = cmd->nbd;
+ struct nbd_config *config;
+ struct nbd_sock *nsock;
+ int ret;
+
+ config = nbd_get_config_unlocked(nbd);
+ if (!config) {
+ dev_err_ratelimited(disk_to_dev(nbd->disk),
+ "Socks array is empty\n");
+ return -EINVAL;
+ }
+
+ if (index >= config->num_connections) {
+ dev_err_ratelimited(disk_to_dev(nbd->disk),
+ "Attempted send on invalid socket\n");
+ nbd_config_put(nbd);
+ return -EINVAL;
+ }
+ cmd->status = BLK_STS_OK;
+again:
+ nsock = config->socks[index];
+ mutex_lock(&nsock->tx_lock);
+ if (nsock->dead) {
+ int old_index = index;
+ index = find_fallback(nbd, index);
+ mutex_unlock(&nsock->tx_lock);
+ if (index < 0) {
+ if (wait_for_reconnect(nbd)) {
+ index = old_index;
+ goto again;
+ }
+ /* All the sockets should already be down at this point,
+ * we just want to make sure that DISCONNECTED is set so
+ * any requests that come in that were queue'ed waiting
+ * for the reconnect timer don't trigger the timer again
+ * and instead just error out.
+ */
+ sock_shutdown(nbd);
+ nbd_config_put(nbd);
+ return -EIO;
+ }
+ goto again;
+ }
+
+ /* Handle the case that we have a pending request that was partially
+ * transmitted that _has_ to be serviced first. We need to call requeue
+ * here so that it gets put _after_ the request that is already on the
+ * dispatch list.
+ */
+ blk_mq_start_request(req);
+ if (unlikely(nsock->pending && nsock->pending != req)) {
+ nbd_requeue_cmd(cmd);
+ ret = 0;
+ goto out;
+ }
+ /*
+ * Some failures are related to the link going down, so anything that
+ * returns EAGAIN can be retried on a different socket.
+ */
+ ret = nbd_send_cmd(nbd, cmd, index);
+ /*
+ * Access to this flag is protected by cmd->lock, thus it's safe to set
+ * the flag after nbd_send_cmd() succeed to send request to server.
+ */
+ if (!ret)
+ __set_bit(NBD_CMD_INFLIGHT, &cmd->flags);
+ else if (ret == -EAGAIN) {
+ dev_err_ratelimited(disk_to_dev(nbd->disk),
+ "Request send failed, requeueing\n");
+ nbd_mark_nsock_dead(nbd, nsock, 1);
+ nbd_requeue_cmd(cmd);
+ ret = 0;
+ }
+out:
+ mutex_unlock(&nsock->tx_lock);
+ nbd_config_put(nbd);
+ return ret;
+}
+
+static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
+ const struct blk_mq_queue_data *bd)
+{
+ struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
+ int ret;
+
+ /*
+ * Since we look at the bio's to send the request over the network we
+ * need to make sure the completion work doesn't mark this request done
+ * before we are done doing our send. This keeps us from dereferencing
+ * freed data if we have particularly fast completions (ie we get the
+ * completion before we exit sock_xmit on the last bvec) or in the case
+ * that the server is misbehaving (or there was an error) before we're
+ * done sending everything over the wire.
+ */
+ 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
+ * this case we need to return that we are busy, otherwise error out as
+ * appropriate.
+ */
+ ret = nbd_handle_cmd(cmd, hctx->queue_num);
+ if (ret < 0)
+ ret = BLK_STS_IOERR;
+ else if (!ret)
+ ret = BLK_STS_OK;
+ mutex_unlock(&cmd->lock);
+
+ return ret;
+}
+
+static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd,
+ int *err)
+{
+ struct socket *sock;
+
+ *err = 0;
+ sock = sockfd_lookup(fd, err);
+ if (!sock)
+ return NULL;
+
+ if (sock->ops->shutdown == sock_no_shutdown) {
+ dev_err(disk_to_dev(nbd->disk), "Unsupported socket: shutdown callout must be supported.\n");
+ *err = -EINVAL;
+ sockfd_put(sock);
+ return NULL;
+ }
+
+ return sock;
+}
+
+static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
+ bool netlink)
+{
+ struct nbd_config *config = nbd->config;
+ struct socket *sock;
+ struct nbd_sock **socks;
+ struct nbd_sock *nsock;
+ int err;
+
+ /* Arg will be cast to int, check it to avoid overflow */
+ if (arg > INT_MAX)
+ return -EINVAL;
+ sock = nbd_get_socket(nbd, arg, &err);
+ if (!sock)
+ return err;
+
+ /*
+ * We need to make sure we don't get any errant requests while we're
+ * reallocating the ->socks array.
+ */
+ blk_mq_freeze_queue(nbd->disk->queue);
+
+ if (!netlink && !nbd->task_setup &&
+ !test_bit(NBD_RT_BOUND, &config->runtime_flags))
+ nbd->task_setup = current;
+
+ if (!netlink &&
+ (nbd->task_setup != current ||
+ test_bit(NBD_RT_BOUND, &config->runtime_flags))) {
+ dev_err(disk_to_dev(nbd->disk),
+ "Device being setup by another task");
+ err = -EBUSY;
+ goto put_socket;
+ }
+
+ nsock = kzalloc(sizeof(*nsock), GFP_KERNEL);
+ if (!nsock) {
+ err = -ENOMEM;
+ goto put_socket;
+ }
+
+ socks = krealloc(config->socks, (config->num_connections + 1) *
+ sizeof(struct nbd_sock *), GFP_KERNEL);
+ if (!socks) {
+ kfree(nsock);
+ err = -ENOMEM;
+ goto put_socket;
+ }
+
+ config->socks = socks;
+
+ nsock->fallback_index = -1;
+ nsock->dead = false;
+ mutex_init(&nsock->tx_lock);
+ nsock->sock = sock;
+ nsock->pending = NULL;
+ nsock->sent = 0;
+ nsock->cookie = 0;
+ socks[config->num_connections++] = nsock;
+ atomic_inc(&config->live_connections);
+ blk_mq_unfreeze_queue(nbd->disk->queue);
+
+ return 0;
+
+put_socket:
+ blk_mq_unfreeze_queue(nbd->disk->queue);
+ sockfd_put(sock);
+ return err;
+}
+
+static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
+{
+ struct nbd_config *config = nbd->config;
+ struct socket *sock, *old;
+ struct recv_thread_args *args;
+ int i;
+ int err;
+
+ sock = nbd_get_socket(nbd, arg, &err);
+ if (!sock)
+ return err;
+
+ args = kzalloc(sizeof(*args), GFP_KERNEL);
+ if (!args) {
+ sockfd_put(sock);
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < config->num_connections; i++) {
+ struct nbd_sock *nsock = config->socks[i];
+
+ if (!nsock->dead)
+ continue;
+
+ mutex_lock(&nsock->tx_lock);
+ if (!nsock->dead) {
+ mutex_unlock(&nsock->tx_lock);
+ continue;
+ }
+ sk_set_memalloc(sock->sk);
+ if (nbd->tag_set.timeout)
+ sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
+ atomic_inc(&config->recv_threads);
+ refcount_inc(&nbd->config_refs);
+ old = nsock->sock;
+ nsock->fallback_index = -1;
+ nsock->sock = sock;
+ nsock->dead = false;
+ INIT_WORK(&args->work, recv_work);
+ args->index = i;
+ args->nbd = nbd;
+ args->nsock = nsock;
+ nsock->cookie++;
+ mutex_unlock(&nsock->tx_lock);
+ sockfd_put(old);
+
+ clear_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
+
+ /* We take the tx_mutex in an error path in the recv_work, so we
+ * need to queue_work outside of the tx_mutex.
+ */
+ queue_work(nbd->recv_workq, &args->work);
+
+ atomic_inc(&config->live_connections);
+ wake_up(&config->conn_wait);
+ return 0;
+ }
+ sockfd_put(sock);
+ kfree(args);
+ return -ENOSPC;
+}
+
+static void nbd_bdev_reset(struct nbd_device *nbd)
+{
+ if (disk_openers(nbd->disk) > 1)
+ return;
+ set_capacity(nbd->disk, 0);
+}
+
+static void nbd_parse_flags(struct nbd_device *nbd)
+{
+ struct nbd_config *config = nbd->config;
+ if (config->flags & NBD_FLAG_READ_ONLY)
+ set_disk_ro(nbd->disk, true);
+ else
+ set_disk_ro(nbd->disk, false);
+ if (config->flags & NBD_FLAG_SEND_FLUSH) {
+ if (config->flags & NBD_FLAG_SEND_FUA)
+ blk_queue_write_cache(nbd->disk->queue, true, true);
+ else
+ blk_queue_write_cache(nbd->disk->queue, true, false);
+ }
+ else
+ blk_queue_write_cache(nbd->disk->queue, false, false);
+}
+
+static void send_disconnects(struct nbd_device *nbd)
+{
+ struct nbd_config *config = nbd->config;
+ struct nbd_request request = {
+ .magic = htonl(NBD_REQUEST_MAGIC),
+ .type = htonl(NBD_CMD_DISC),
+ };
+ struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
+ struct iov_iter from;
+ int i, ret;
+
+ for (i = 0; i < config->num_connections; i++) {
+ struct nbd_sock *nsock = config->socks[i];
+
+ iov_iter_kvec(&from, ITER_SOURCE, &iov, 1, sizeof(request));
+ mutex_lock(&nsock->tx_lock);
+ ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
+ if (ret < 0)
+ dev_err(disk_to_dev(nbd->disk),
+ "Send disconnect failed %d\n", ret);
+ mutex_unlock(&nsock->tx_lock);
+ }
+}
+
+static int nbd_disconnect(struct nbd_device *nbd)
+{
+ struct nbd_config *config = nbd->config;
+
+ dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
+ set_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
+ set_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags);
+ send_disconnects(nbd);
+ return 0;
+}
+
+static void nbd_clear_sock(struct nbd_device *nbd)
+{
+ sock_shutdown(nbd);
+ nbd_clear_que(nbd);
+ nbd->task_setup = NULL;
+}
+
+static void nbd_config_put(struct nbd_device *nbd)
+{
+ if (refcount_dec_and_mutex_lock(&nbd->config_refs,
+ &nbd->config_lock)) {
+ struct nbd_config *config = nbd->config;
+ nbd_dev_dbg_close(nbd);
+ invalidate_disk(nbd->disk);
+ if (nbd->config->bytesize)
+ kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
+ if (test_and_clear_bit(NBD_RT_HAS_PID_FILE,
+ &config->runtime_flags))
+ device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
+ nbd->pid = 0;
+ if (test_and_clear_bit(NBD_RT_HAS_BACKEND_FILE,
+ &config->runtime_flags)) {
+ device_remove_file(disk_to_dev(nbd->disk), &backend_attr);
+ kfree(nbd->backend);
+ nbd->backend = NULL;
+ }
+ nbd_clear_sock(nbd);
+ if (config->num_connections) {
+ int i;
+ for (i = 0; i < config->num_connections; i++) {
+ sockfd_put(config->socks[i]->sock);
+ kfree(config->socks[i]);
+ }
+ kfree(config->socks);
+ }
+ kfree(nbd->config);
+ nbd->config = NULL;
+
+ nbd->tag_set.timeout = 0;
+ nbd->disk->queue->limits.discard_granularity = 0;
+ blk_queue_max_discard_sectors(nbd->disk->queue, 0);
+
+ mutex_unlock(&nbd->config_lock);
+ nbd_put(nbd);
+ module_put(THIS_MODULE);
+ }
+}
+
+static int nbd_start_device(struct nbd_device *nbd)
+{
+ struct nbd_config *config = nbd->config;
+ int num_connections = config->num_connections;
+ int error = 0, i;
+
+ if (nbd->pid)
+ return -EBUSY;
+ if (!config->socks)
+ return -EINVAL;
+ if (num_connections > 1 &&
+ !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
+ dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
+ return -EINVAL;
+ }
+
+ blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
+ nbd->pid = task_pid_nr(current);
+
+ nbd_parse_flags(nbd);
+
+ error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
+ if (error) {
+ dev_err(disk_to_dev(nbd->disk), "device_create_file failed for pid!\n");
+ return error;
+ }
+ set_bit(NBD_RT_HAS_PID_FILE, &config->runtime_flags);
+
+ nbd_dev_dbg_init(nbd);
+ for (i = 0; i < num_connections; i++) {
+ struct recv_thread_args *args;
+
+ args = kzalloc(sizeof(*args), GFP_KERNEL);
+ if (!args) {
+ sock_shutdown(nbd);
+ /*
+ * If num_connections is m (2 < m),
+ * and NO.1 ~ NO.n(1 < n < m) kzallocs are successful.
+ * But NO.(n + 1) failed. We still have n recv threads.
+ * So, add flush_workqueue here to prevent recv threads
+ * dropping the last config_refs and trying to destroy
+ * the workqueue from inside the workqueue.
+ */
+ if (i)
+ flush_workqueue(nbd->recv_workq);
+ return -ENOMEM;
+ }
+ sk_set_memalloc(config->socks[i]->sock->sk);
+ if (nbd->tag_set.timeout)
+ config->socks[i]->sock->sk->sk_sndtimeo =
+ nbd->tag_set.timeout;
+ atomic_inc(&config->recv_threads);
+ refcount_inc(&nbd->config_refs);
+ INIT_WORK(&args->work, recv_work);
+ args->nbd = nbd;
+ args->nsock = config->socks[i];
+ args->index = i;
+ queue_work(nbd->recv_workq, &args->work);
+ }
+ return nbd_set_size(nbd, config->bytesize, nbd_blksize(config));
+}
+
+static int nbd_start_device_ioctl(struct nbd_device *nbd)
+{
+ struct nbd_config *config = nbd->config;
+ int ret;
+
+ ret = nbd_start_device(nbd);
+ if (ret)
+ return ret;
+
+ if (max_part)
+ set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
+ mutex_unlock(&nbd->config_lock);
+ ret = wait_event_interruptible(config->recv_wq,
+ atomic_read(&config->recv_threads) == 0);
+ if (ret) {
+ sock_shutdown(nbd);
+ nbd_clear_que(nbd);
+ }
+
+ flush_workqueue(nbd->recv_workq);
+ mutex_lock(&nbd->config_lock);
+ nbd_bdev_reset(nbd);
+ /* user requested, ignore socket errors */
+ if (test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags))
+ ret = 0;
+ if (test_bit(NBD_RT_TIMEDOUT, &config->runtime_flags))
+ ret = -ETIMEDOUT;
+ return ret;
+}
+
+static void nbd_clear_sock_ioctl(struct nbd_device *nbd)
+{
+ nbd_clear_sock(nbd);
+ disk_force_media_change(nbd->disk);
+ nbd_bdev_reset(nbd);
+ if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
+ &nbd->config->runtime_flags))
+ nbd_config_put(nbd);
+}
+
+static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout)
+{
+ nbd->tag_set.timeout = timeout * HZ;
+ if (timeout)
+ blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
+ else
+ blk_queue_rq_timeout(nbd->disk->queue, 30 * HZ);
+}
+
+/* Must be called with config_lock held */
+static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
+ unsigned int cmd, unsigned long arg)
+{
+ struct nbd_config *config = nbd->config;
+ loff_t bytesize;
+
+ switch (cmd) {
+ case NBD_DISCONNECT:
+ return nbd_disconnect(nbd);
+ case NBD_CLEAR_SOCK:
+ nbd_clear_sock_ioctl(nbd);
+ return 0;
+ case NBD_SET_SOCK:
+ return nbd_add_socket(nbd, arg, false);
+ case NBD_SET_BLKSIZE:
+ return nbd_set_size(nbd, config->bytesize, arg);
+ case NBD_SET_SIZE:
+ return nbd_set_size(nbd, arg, nbd_blksize(config));
+ case NBD_SET_SIZE_BLOCKS:
+ if (check_shl_overflow(arg, config->blksize_bits, &bytesize))
+ return -EINVAL;
+ return nbd_set_size(nbd, bytesize, nbd_blksize(config));
+ case NBD_SET_TIMEOUT:
+ nbd_set_cmd_timeout(nbd, arg);
+ return 0;
+
+ case NBD_SET_FLAGS:
+ config->flags = arg;
+ return 0;
+ case NBD_DO_IT:
+ return nbd_start_device_ioctl(nbd);
+ case NBD_CLEAR_QUE:
+ /*
+ * This is for compatibility only. The queue is always cleared
+ * by NBD_DO_IT or NBD_CLEAR_SOCK.
+ */
+ return 0;
+ case NBD_PRINT_DEBUG:
+ /*
+ * For compatibility only, we no longer keep a list of
+ * outstanding requests.
+ */
+ return 0;
+ }
+ return -ENOTTY;
+}
+
+static int nbd_ioctl(struct block_device *bdev, blk_mode_t mode,
+ unsigned int cmd, unsigned long arg)
+{
+ struct nbd_device *nbd = bdev->bd_disk->private_data;
+ struct nbd_config *config = nbd->config;
+ int error = -EINVAL;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ /* The block layer will pass back some non-nbd ioctls in case we have
+ * special handling for them, but we don't so just return an error.
+ */
+ if (_IOC_TYPE(cmd) != 0xab)
+ return -EINVAL;
+
+ mutex_lock(&nbd->config_lock);
+
+ /* Don't allow ioctl operations on a nbd device that was created with
+ * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
+ */
+ if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
+ (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
+ error = __nbd_ioctl(bdev, nbd, cmd, arg);
+ else
+ dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
+ mutex_unlock(&nbd->config_lock);
+ return error;
+}
+
+static int nbd_alloc_and_init_config(struct nbd_device *nbd)
+{
+ struct nbd_config *config;
+
+ if (WARN_ON(nbd->config))
+ return -EINVAL;
+
+ if (!try_module_get(THIS_MODULE))
+ return -ENODEV;
+
+ config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
+ if (!config) {
+ module_put(THIS_MODULE);
+ return -ENOMEM;
+ }
+
+ atomic_set(&config->recv_threads, 0);
+ init_waitqueue_head(&config->recv_wq);
+ init_waitqueue_head(&config->conn_wait);
+ config->blksize_bits = NBD_DEF_BLKSIZE_BITS;
+ atomic_set(&config->live_connections, 0);
+
+ nbd->config = config;
+ /*
+ * Order refcount_set(&nbd->config_refs, 1) and nbd->config assignment,
+ * its pair is the barrier in nbd_get_config_unlocked().
+ * So nbd_get_config_unlocked() won't see nbd->config as null after
+ * refcount_inc_not_zero() succeed.
+ */
+ smp_mb__before_atomic();
+ refcount_set(&nbd->config_refs, 1);
+
+ return 0;
+}
+
+static int nbd_open(struct gendisk *disk, blk_mode_t mode)
+{
+ struct nbd_device *nbd;
+ struct nbd_config *config;
+ int ret = 0;
+
+ mutex_lock(&nbd_index_mutex);
+ nbd = disk->private_data;
+ if (!nbd) {
+ ret = -ENXIO;
+ goto out;
+ }
+ if (!refcount_inc_not_zero(&nbd->refs)) {
+ ret = -ENXIO;
+ goto out;
+ }
+
+ config = nbd_get_config_unlocked(nbd);
+ if (!config) {
+ mutex_lock(&nbd->config_lock);
+ if (refcount_inc_not_zero(&nbd->config_refs)) {
+ mutex_unlock(&nbd->config_lock);
+ goto out;
+ }
+ ret = nbd_alloc_and_init_config(nbd);
+ if (ret) {
+ mutex_unlock(&nbd->config_lock);
+ goto out;
+ }
+
+ refcount_inc(&nbd->refs);
+ mutex_unlock(&nbd->config_lock);
+ if (max_part)
+ set_bit(GD_NEED_PART_SCAN, &disk->state);
+ } else if (nbd_disconnected(config)) {
+ if (max_part)
+ set_bit(GD_NEED_PART_SCAN, &disk->state);
+ }
+out:
+ mutex_unlock(&nbd_index_mutex);
+ return ret;
+}
+
+static void nbd_release(struct gendisk *disk)
+{
+ struct nbd_device *nbd = disk->private_data;
+
+ if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
+ disk_openers(disk) == 0)
+ nbd_disconnect_and_put(nbd);
+
+ nbd_config_put(nbd);
+ nbd_put(nbd);
+}
+
+static void nbd_free_disk(struct gendisk *disk)
+{
+ struct nbd_device *nbd = disk->private_data;
+
+ kfree(nbd);
+}
+
+static const struct block_device_operations nbd_fops =
+{
+ .owner = THIS_MODULE,
+ .open = nbd_open,
+ .release = nbd_release,
+ .ioctl = nbd_ioctl,
+ .compat_ioctl = nbd_ioctl,
+ .free_disk = nbd_free_disk,
+};
+
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+
+static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
+{
+ struct nbd_device *nbd = s->private;
+
+ if (nbd->pid)
+ seq_printf(s, "recv: %d\n", nbd->pid);
+
+ return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(nbd_dbg_tasks);
+
+static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
+{
+ struct nbd_device *nbd = s->private;
+ u32 flags = nbd->config->flags;
+
+ seq_printf(s, "Hex: 0x%08x\n\n", flags);
+
+ seq_puts(s, "Known flags:\n");
+
+ if (flags & NBD_FLAG_HAS_FLAGS)
+ seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
+ if (flags & NBD_FLAG_READ_ONLY)
+ seq_puts(s, "NBD_FLAG_READ_ONLY\n");
+ if (flags & NBD_FLAG_SEND_FLUSH)
+ seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
+ if (flags & NBD_FLAG_SEND_FUA)
+ seq_puts(s, "NBD_FLAG_SEND_FUA\n");
+ if (flags & NBD_FLAG_SEND_TRIM)
+ seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
+
+ return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(nbd_dbg_flags);
+
+static int nbd_dev_dbg_init(struct nbd_device *nbd)
+{
+ struct dentry *dir;
+ struct nbd_config *config = nbd->config;
+
+ if (!nbd_dbg_dir)
+ return -EIO;
+
+ dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
+ if (IS_ERR(dir)) {
+ dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
+ nbd_name(nbd));
+ return -EIO;
+ }
+ config->dbg_dir = dir;
+
+ debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_fops);
+ debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
+ debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
+ debugfs_create_u32("blocksize_bits", 0444, dir, &config->blksize_bits);
+ debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_fops);
+
+ return 0;
+}
+
+static void nbd_dev_dbg_close(struct nbd_device *nbd)
+{
+ debugfs_remove_recursive(nbd->config->dbg_dir);
+}
+
+static int nbd_dbg_init(void)
+{
+ struct dentry *dbg_dir;
+
+ dbg_dir = debugfs_create_dir("nbd", NULL);
+ if (IS_ERR(dbg_dir))
+ return -EIO;
+
+ nbd_dbg_dir = dbg_dir;
+
+ return 0;
+}
+
+static void nbd_dbg_close(void)
+{
+ debugfs_remove_recursive(nbd_dbg_dir);
+}
+
+#else /* IS_ENABLED(CONFIG_DEBUG_FS) */
+
+static int nbd_dev_dbg_init(struct nbd_device *nbd)
+{
+ return 0;
+}
+
+static void nbd_dev_dbg_close(struct nbd_device *nbd)
+{
+}
+
+static int nbd_dbg_init(void)
+{
+ return 0;
+}
+
+static void nbd_dbg_close(void)
+{
+}
+
+#endif
+
+static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
+ unsigned int hctx_idx, unsigned int numa_node)
+{
+ struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
+ cmd->nbd = set->driver_data;
+ cmd->flags = 0;
+ mutex_init(&cmd->lock);
+ return 0;
+}
+
+static const struct blk_mq_ops nbd_mq_ops = {
+ .queue_rq = nbd_queue_rq,
+ .complete = nbd_complete_rq,
+ .init_request = nbd_init_request,
+ .timeout = nbd_xmit_timeout,
+};
+
+static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
+{
+ struct nbd_device *nbd;
+ struct gendisk *disk;
+ int err = -ENOMEM;
+
+ nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
+ if (!nbd)
+ goto out;
+
+ nbd->tag_set.ops = &nbd_mq_ops;
+ nbd->tag_set.nr_hw_queues = 1;
+ nbd->tag_set.queue_depth = 128;
+ nbd->tag_set.numa_node = NUMA_NO_NODE;
+ nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
+ nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
+ BLK_MQ_F_BLOCKING;
+ nbd->tag_set.driver_data = nbd;
+ INIT_WORK(&nbd->remove_work, nbd_dev_remove_work);
+ nbd->backend = NULL;
+
+ err = blk_mq_alloc_tag_set(&nbd->tag_set);
+ if (err)
+ goto out_free_nbd;
+
+ mutex_lock(&nbd_index_mutex);
+ if (index >= 0) {
+ err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
+ GFP_KERNEL);
+ if (err == -ENOSPC)
+ err = -EEXIST;
+ } else {
+ err = idr_alloc(&nbd_index_idr, nbd, 0,
+ (MINORMASK >> part_shift) + 1, GFP_KERNEL);
+ if (err >= 0)
+ index = err;
+ }
+ nbd->index = index;
+ mutex_unlock(&nbd_index_mutex);
+ if (err < 0)
+ goto out_free_tags;
+
+ disk = blk_mq_alloc_disk(&nbd->tag_set, NULL);
+ if (IS_ERR(disk)) {
+ err = PTR_ERR(disk);
+ goto out_free_idr;
+ }
+ nbd->disk = disk;
+
+ nbd->recv_workq = alloc_workqueue("nbd%d-recv",
+ WQ_MEM_RECLAIM | WQ_HIGHPRI |
+ WQ_UNBOUND, 0, nbd->index);
+ if (!nbd->recv_workq) {
+ dev_err(disk_to_dev(nbd->disk), "Could not allocate knbd recv work queue.\n");
+ err = -ENOMEM;
+ goto out_err_disk;
+ }
+
+ /*
+ * Tell the block layer that we are not a rotational device
+ */
+ blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
+ disk->queue->limits.discard_granularity = 0;
+ blk_queue_max_discard_sectors(disk->queue, 0);
+ blk_queue_max_segment_size(disk->queue, UINT_MAX);
+ blk_queue_max_segments(disk->queue, USHRT_MAX);
+ blk_queue_max_hw_sectors(disk->queue, 65536);
+ disk->queue->limits.max_sectors = 256;
+
+ mutex_init(&nbd->config_lock);
+ refcount_set(&nbd->config_refs, 0);
+ /*
+ * Start out with a zero references to keep other threads from using
+ * this device until it is fully initialized.
+ */
+ refcount_set(&nbd->refs, 0);
+ INIT_LIST_HEAD(&nbd->list);
+ disk->major = NBD_MAJOR;
+ disk->first_minor = index << part_shift;
+ disk->minors = 1 << part_shift;
+ disk->fops = &nbd_fops;
+ disk->private_data = nbd;
+ sprintf(disk->disk_name, "nbd%d", index);
+ err = add_disk(disk);
+ if (err)
+ goto out_free_work;
+
+ /*
+ * Now publish the device.
+ */
+ refcount_set(&nbd->refs, refs);
+ nbd_total_devices++;
+ return nbd;
+
+out_free_work:
+ destroy_workqueue(nbd->recv_workq);
+out_err_disk:
+ put_disk(disk);
+out_free_idr:
+ mutex_lock(&nbd_index_mutex);
+ idr_remove(&nbd_index_idr, index);
+ mutex_unlock(&nbd_index_mutex);
+out_free_tags:
+ blk_mq_free_tag_set(&nbd->tag_set);
+out_free_nbd:
+ kfree(nbd);
+out:
+ return ERR_PTR(err);
+}
+
+static struct nbd_device *nbd_find_get_unused(void)
+{
+ struct nbd_device *nbd;
+ int id;
+
+ lockdep_assert_held(&nbd_index_mutex);
+
+ idr_for_each_entry(&nbd_index_idr, nbd, id) {
+ if (refcount_read(&nbd->config_refs) ||
+ test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags))
+ continue;
+ if (refcount_inc_not_zero(&nbd->refs))
+ return nbd;
+ }
+
+ return NULL;
+}
+
+/* Netlink interface. */
+static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
+ [NBD_ATTR_INDEX] = { .type = NLA_U32 },
+ [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
+ [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
+ [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
+ [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
+ [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
+ [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
+ [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
+ [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
+ [NBD_ATTR_BACKEND_IDENTIFIER] = { .type = NLA_STRING},
+};
+
+static const struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
+ [NBD_SOCK_FD] = { .type = NLA_U32 },
+};
+
+/* We don't use this right now since we don't parse the incoming list, but we
+ * still want it here so userspace knows what to expect.
+ */
+static const struct nla_policy __attribute__((unused))
+nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
+ [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
+ [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
+};
+
+static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd)
+{
+ struct nbd_config *config = nbd->config;
+ u64 bsize = nbd_blksize(config);
+ u64 bytes = config->bytesize;
+
+ if (info->attrs[NBD_ATTR_SIZE_BYTES])
+ bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
+
+ if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES])
+ bsize = nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
+
+ if (bytes != config->bytesize || bsize != nbd_blksize(config))
+ return nbd_set_size(nbd, bytes, bsize);
+ return 0;
+}
+
+static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
+{
+ struct nbd_device *nbd;
+ struct nbd_config *config;
+ int index = -1;
+ int ret;
+ bool put_dev = false;
+
+ if (!netlink_capable(skb, CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (info->attrs[NBD_ATTR_INDEX]) {
+ index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
+
+ /*
+ * Too big first_minor can cause duplicate creation of
+ * sysfs files/links, since index << part_shift might overflow, or
+ * MKDEV() expect that the max bits of first_minor is 20.
+ */
+ if (index < 0 || index > MINORMASK >> part_shift) {
+ pr_err("illegal input index %d\n", index);
+ return -EINVAL;
+ }
+ }
+ if (GENL_REQ_ATTR_CHECK(info, NBD_ATTR_SOCKETS)) {
+ pr_err("must specify at least one socket\n");
+ return -EINVAL;
+ }
+ if (GENL_REQ_ATTR_CHECK(info, NBD_ATTR_SIZE_BYTES)) {
+ pr_err("must specify a size in bytes for the device\n");
+ return -EINVAL;
+ }
+again:
+ mutex_lock(&nbd_index_mutex);
+ if (index == -1) {
+ nbd = nbd_find_get_unused();
+ } else {
+ nbd = idr_find(&nbd_index_idr, index);
+ if (nbd) {
+ if ((test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&
+ test_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags)) ||
+ !refcount_inc_not_zero(&nbd->refs)) {
+ mutex_unlock(&nbd_index_mutex);
+ pr_err("device at index %d is going down\n",
+ index);
+ return -EINVAL;
+ }
+ }
+ }
+ mutex_unlock(&nbd_index_mutex);
+
+ if (!nbd) {
+ nbd = nbd_dev_add(index, 2);
+ if (IS_ERR(nbd)) {
+ pr_err("failed to add new device\n");
+ return PTR_ERR(nbd);
+ }
+ }
+
+ mutex_lock(&nbd->config_lock);
+ if (refcount_read(&nbd->config_refs)) {
+ mutex_unlock(&nbd->config_lock);
+ nbd_put(nbd);
+ if (index == -1)
+ goto again;
+ pr_err("nbd%d already in use\n", index);
+ return -EBUSY;
+ }
+
+ ret = nbd_alloc_and_init_config(nbd);
+ if (ret) {
+ mutex_unlock(&nbd->config_lock);
+ nbd_put(nbd);
+ pr_err("couldn't allocate config\n");
+ return ret;
+ }
+
+ config = nbd->config;
+ set_bit(NBD_RT_BOUND, &config->runtime_flags);
+ ret = nbd_genl_size_set(info, nbd);
+ if (ret)
+ goto out;
+
+ if (info->attrs[NBD_ATTR_TIMEOUT])
+ nbd_set_cmd_timeout(nbd,
+ nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
+ if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
+ config->dead_conn_timeout =
+ nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
+ config->dead_conn_timeout *= HZ;
+ }
+ if (info->attrs[NBD_ATTR_SERVER_FLAGS])
+ config->flags =
+ nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
+ if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
+ u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
+ if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
+ /*
+ * We have 1 ref to keep the device around, and then 1
+ * ref for our current operation here, which will be
+ * inherited by the config. If we already have
+ * DESTROY_ON_DISCONNECT set then we know we don't have
+ * that extra ref already held so we don't need the
+ * put_dev.
+ */
+ if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
+ &nbd->flags))
+ put_dev = true;
+ } else {
+ if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
+ &nbd->flags))
+ refcount_inc(&nbd->refs);
+ }
+ if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
+ set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
+ &config->runtime_flags);
+ }
+ }
+
+ if (info->attrs[NBD_ATTR_SOCKETS]) {
+ struct nlattr *attr;
+ int rem, fd;
+
+ nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
+ rem) {
+ struct nlattr *socks[NBD_SOCK_MAX+1];
+
+ if (nla_type(attr) != NBD_SOCK_ITEM) {
+ pr_err("socks must be embedded in a SOCK_ITEM attr\n");
+ ret = -EINVAL;
+ goto out;
+ }
+ ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
+ attr,
+ nbd_sock_policy,
+ info->extack);
+ if (ret != 0) {
+ pr_err("error processing sock list\n");
+ ret = -EINVAL;
+ goto out;
+ }
+ if (!socks[NBD_SOCK_FD])
+ continue;
+ fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
+ ret = nbd_add_socket(nbd, fd, true);
+ if (ret)
+ goto out;
+ }
+ }
+ ret = nbd_start_device(nbd);
+ if (ret)
+ goto out;
+ if (info->attrs[NBD_ATTR_BACKEND_IDENTIFIER]) {
+ nbd->backend = nla_strdup(info->attrs[NBD_ATTR_BACKEND_IDENTIFIER],
+ GFP_KERNEL);
+ if (!nbd->backend) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+ ret = device_create_file(disk_to_dev(nbd->disk), &backend_attr);
+ if (ret) {
+ dev_err(disk_to_dev(nbd->disk),
+ "device_create_file failed for backend!\n");
+ goto out;
+ }
+ set_bit(NBD_RT_HAS_BACKEND_FILE, &config->runtime_flags);
+out:
+ mutex_unlock(&nbd->config_lock);
+ if (!ret) {
+ set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);
+ refcount_inc(&nbd->config_refs);
+ nbd_connect_reply(info, nbd->index);
+ }
+ nbd_config_put(nbd);
+ if (put_dev)
+ nbd_put(nbd);
+ return ret;
+}
+
+static void nbd_disconnect_and_put(struct nbd_device *nbd)
+{
+ mutex_lock(&nbd->config_lock);
+ nbd_disconnect(nbd);
+ sock_shutdown(nbd);
+ wake_up(&nbd->config->conn_wait);
+ /*
+ * Make sure recv thread has finished, we can safely call nbd_clear_que()
+ * to cancel the inflight I/Os.
+ */
+ flush_workqueue(nbd->recv_workq);
+ nbd_clear_que(nbd);
+ nbd->task_setup = NULL;
+ mutex_unlock(&nbd->config_lock);
+
+ if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
+ &nbd->config->runtime_flags))
+ nbd_config_put(nbd);
+}
+
+static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
+{
+ struct nbd_device *nbd;
+ int index;
+
+ if (!netlink_capable(skb, CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (GENL_REQ_ATTR_CHECK(info, NBD_ATTR_INDEX)) {
+ pr_err("must specify an index to disconnect\n");
+ return -EINVAL;
+ }
+ index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
+ mutex_lock(&nbd_index_mutex);
+ nbd = idr_find(&nbd_index_idr, index);
+ if (!nbd) {
+ mutex_unlock(&nbd_index_mutex);
+ pr_err("couldn't find device at index %d\n", index);
+ return -EINVAL;
+ }
+ if (!refcount_inc_not_zero(&nbd->refs)) {
+ mutex_unlock(&nbd_index_mutex);
+ pr_err("device at index %d is going down\n", index);
+ return -EINVAL;
+ }
+ mutex_unlock(&nbd_index_mutex);
+ if (!refcount_inc_not_zero(&nbd->config_refs))
+ goto put_nbd;
+ nbd_disconnect_and_put(nbd);
+ nbd_config_put(nbd);
+put_nbd:
+ nbd_put(nbd);
+ return 0;
+}
+
+static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
+{
+ struct nbd_device *nbd = NULL;
+ struct nbd_config *config;
+ int index;
+ int ret = 0;
+ bool put_dev = false;
+
+ if (!netlink_capable(skb, CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (GENL_REQ_ATTR_CHECK(info, NBD_ATTR_INDEX)) {
+ pr_err("must specify a device to reconfigure\n");
+ return -EINVAL;
+ }
+ index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
+ mutex_lock(&nbd_index_mutex);
+ nbd = idr_find(&nbd_index_idr, index);
+ if (!nbd) {
+ mutex_unlock(&nbd_index_mutex);
+ pr_err("couldn't find a device at index %d\n", index);
+ return -EINVAL;
+ }
+ if (nbd->backend) {
+ if (info->attrs[NBD_ATTR_BACKEND_IDENTIFIER]) {
+ if (nla_strcmp(info->attrs[NBD_ATTR_BACKEND_IDENTIFIER],
+ nbd->backend)) {
+ mutex_unlock(&nbd_index_mutex);
+ dev_err(nbd_to_dev(nbd),
+ "backend image doesn't match with %s\n",
+ nbd->backend);
+ return -EINVAL;
+ }
+ } else {
+ mutex_unlock(&nbd_index_mutex);
+ dev_err(nbd_to_dev(nbd), "must specify backend\n");
+ return -EINVAL;
+ }
+ }
+ if (!refcount_inc_not_zero(&nbd->refs)) {
+ mutex_unlock(&nbd_index_mutex);
+ pr_err("device at index %d is going down\n", index);
+ return -EINVAL;
+ }
+ mutex_unlock(&nbd_index_mutex);
+
+ config = nbd_get_config_unlocked(nbd);
+ if (!config) {
+ dev_err(nbd_to_dev(nbd),
+ "not configured, cannot reconfigure\n");
+ nbd_put(nbd);
+ return -EINVAL;
+ }
+
+ mutex_lock(&nbd->config_lock);
+ if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
+ !nbd->pid) {
+ dev_err(nbd_to_dev(nbd),
+ "not configured, cannot reconfigure\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = nbd_genl_size_set(info, nbd);
+ if (ret)
+ goto out;
+
+ if (info->attrs[NBD_ATTR_TIMEOUT])
+ nbd_set_cmd_timeout(nbd,
+ nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
+ if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
+ config->dead_conn_timeout =
+ nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
+ config->dead_conn_timeout *= HZ;
+ }
+ if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
+ u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
+ if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
+ if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
+ &nbd->flags))
+ put_dev = true;
+ } else {
+ if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
+ &nbd->flags))
+ refcount_inc(&nbd->refs);
+ }
+
+ if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
+ set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
+ &config->runtime_flags);
+ } else {
+ clear_bit(NBD_RT_DISCONNECT_ON_CLOSE,
+ &config->runtime_flags);
+ }
+ }
+
+ if (info->attrs[NBD_ATTR_SOCKETS]) {
+ struct nlattr *attr;
+ int rem, fd;
+
+ nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
+ rem) {
+ struct nlattr *socks[NBD_SOCK_MAX+1];
+
+ if (nla_type(attr) != NBD_SOCK_ITEM) {
+ pr_err("socks must be embedded in a SOCK_ITEM attr\n");
+ ret = -EINVAL;
+ goto out;
+ }
+ ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
+ attr,
+ nbd_sock_policy,
+ info->extack);
+ if (ret != 0) {
+ pr_err("error processing sock list\n");
+ ret = -EINVAL;
+ goto out;
+ }
+ if (!socks[NBD_SOCK_FD])
+ continue;
+ fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
+ ret = nbd_reconnect_socket(nbd, fd);
+ if (ret) {
+ if (ret == -ENOSPC)
+ ret = 0;
+ goto out;
+ }
+ dev_info(nbd_to_dev(nbd), "reconnected socket\n");
+ }
+ }
+out:
+ mutex_unlock(&nbd->config_lock);
+ nbd_config_put(nbd);
+ nbd_put(nbd);
+ if (put_dev)
+ nbd_put(nbd);
+ return ret;
+}
+
+static const struct genl_small_ops nbd_connect_genl_ops[] = {
+ {
+ .cmd = NBD_CMD_CONNECT,
+ .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+ .doit = nbd_genl_connect,
+ },
+ {
+ .cmd = NBD_CMD_DISCONNECT,
+ .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+ .doit = nbd_genl_disconnect,
+ },
+ {
+ .cmd = NBD_CMD_RECONFIGURE,
+ .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+ .doit = nbd_genl_reconfigure,
+ },
+ {
+ .cmd = NBD_CMD_STATUS,
+ .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+ .doit = nbd_genl_status,
+ },
+};
+
+static const struct genl_multicast_group nbd_mcast_grps[] = {
+ { .name = NBD_GENL_MCAST_GROUP_NAME, },
+};
+
+static struct genl_family nbd_genl_family __ro_after_init = {
+ .hdrsize = 0,
+ .name = NBD_GENL_FAMILY_NAME,
+ .version = NBD_GENL_VERSION,
+ .module = THIS_MODULE,
+ .small_ops = nbd_connect_genl_ops,
+ .n_small_ops = ARRAY_SIZE(nbd_connect_genl_ops),
+ .resv_start_op = NBD_CMD_STATUS + 1,
+ .maxattr = NBD_ATTR_MAX,
+ .netnsok = 1,
+ .policy = nbd_attr_policy,
+ .mcgrps = nbd_mcast_grps,
+ .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
+};
+MODULE_ALIAS_GENL_FAMILY(NBD_GENL_FAMILY_NAME);
+
+static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
+{
+ struct nlattr *dev_opt;
+ u8 connected = 0;
+ int ret;
+
+ /* This is a little racey, but for status it's ok. The
+ * reason we don't take a ref here is because we can't
+ * take a ref in the index == -1 case as we would need
+ * to put under the nbd_index_mutex, which could
+ * deadlock if we are configured to remove ourselves
+ * once we're disconnected.
+ */
+ if (refcount_read(&nbd->config_refs))
+ connected = 1;
+ dev_opt = nla_nest_start_noflag(reply, NBD_DEVICE_ITEM);
+ if (!dev_opt)
+ return -EMSGSIZE;
+ ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
+ if (ret)
+ return -EMSGSIZE;
+ ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
+ connected);
+ if (ret)
+ return -EMSGSIZE;
+ nla_nest_end(reply, dev_opt);
+ return 0;
+}
+
+static int status_cb(int id, void *ptr, void *data)
+{
+ struct nbd_device *nbd = ptr;
+ return populate_nbd_status(nbd, (struct sk_buff *)data);
+}
+
+static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
+{
+ struct nlattr *dev_list;
+ struct sk_buff *reply;
+ void *reply_head;
+ size_t msg_size;
+ int index = -1;
+ int ret = -ENOMEM;
+
+ if (info->attrs[NBD_ATTR_INDEX])
+ index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
+
+ mutex_lock(&nbd_index_mutex);
+
+ msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
+ nla_attr_size(sizeof(u8)));
+ msg_size *= (index == -1) ? nbd_total_devices : 1;
+
+ reply = genlmsg_new(msg_size, GFP_KERNEL);
+ if (!reply)
+ goto out;
+ reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
+ NBD_CMD_STATUS);
+ if (!reply_head) {
+ nlmsg_free(reply);
+ goto out;
+ }
+
+ dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST);
+ if (index == -1) {
+ ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
+ if (ret) {
+ nlmsg_free(reply);
+ goto out;
+ }
+ } else {
+ struct nbd_device *nbd;
+ nbd = idr_find(&nbd_index_idr, index);
+ if (nbd) {
+ ret = populate_nbd_status(nbd, reply);
+ if (ret) {
+ nlmsg_free(reply);
+ goto out;
+ }
+ }
+ }
+ nla_nest_end(reply, dev_list);
+ genlmsg_end(reply, reply_head);
+ ret = genlmsg_reply(reply, info);
+out:
+ mutex_unlock(&nbd_index_mutex);
+ return ret;
+}
+
+static void nbd_connect_reply(struct genl_info *info, int index)
+{
+ struct sk_buff *skb;
+ void *msg_head;
+ int ret;
+
+ skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
+ if (!skb)
+ return;
+ msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
+ NBD_CMD_CONNECT);
+ if (!msg_head) {
+ nlmsg_free(skb);
+ return;
+ }
+ ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
+ if (ret) {
+ nlmsg_free(skb);
+ return;
+ }
+ genlmsg_end(skb, msg_head);
+ genlmsg_reply(skb, info);
+}
+
+static void nbd_mcast_index(int index)
+{
+ struct sk_buff *skb;
+ void *msg_head;
+ int ret;
+
+ skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
+ if (!skb)
+ return;
+ msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
+ NBD_CMD_LINK_DEAD);
+ if (!msg_head) {
+ nlmsg_free(skb);
+ return;
+ }
+ ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
+ if (ret) {
+ nlmsg_free(skb);
+ return;
+ }
+ genlmsg_end(skb, msg_head);
+ genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
+}
+
+static void nbd_dead_link_work(struct work_struct *work)
+{
+ struct link_dead_args *args = container_of(work, struct link_dead_args,
+ work);
+ nbd_mcast_index(args->index);
+ kfree(args);
+}
+
+static int __init nbd_init(void)
+{
+ int i;
+
+ BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
+
+ if (max_part < 0) {
+ pr_err("max_part must be >= 0\n");
+ return -EINVAL;
+ }
+
+ part_shift = 0;
+ if (max_part > 0) {
+ part_shift = fls(max_part);
+
+ /*
+ * Adjust max_part according to part_shift as it is exported
+ * to user space so that user can know the max number of
+ * partition kernel should be able to manage.
+ *
+ * Note that -1 is required because partition 0 is reserved
+ * for the whole disk.
+ */
+ max_part = (1UL << part_shift) - 1;
+ }
+
+ if ((1UL << part_shift) > DISK_MAX_PARTS)
+ return -EINVAL;
+
+ if (nbds_max > 1UL << (MINORBITS - part_shift))
+ return -EINVAL;
+
+ if (register_blkdev(NBD_MAJOR, "nbd"))
+ return -EIO;
+
+ nbd_del_wq = alloc_workqueue("nbd-del", WQ_UNBOUND, 0);
+ if (!nbd_del_wq) {
+ unregister_blkdev(NBD_MAJOR, "nbd");
+ return -ENOMEM;
+ }
+
+ if (genl_register_family(&nbd_genl_family)) {
+ destroy_workqueue(nbd_del_wq);
+ unregister_blkdev(NBD_MAJOR, "nbd");
+ return -EINVAL;
+ }
+ nbd_dbg_init();
+
+ for (i = 0; i < nbds_max; i++)
+ nbd_dev_add(i, 1);
+ return 0;
+}
+
+static int nbd_exit_cb(int id, void *ptr, void *data)
+{
+ struct list_head *list = (struct list_head *)data;
+ struct nbd_device *nbd = ptr;
+
+ /* Skip nbd that is being removed asynchronously */
+ if (refcount_read(&nbd->refs))
+ list_add_tail(&nbd->list, list);
+
+ return 0;
+}
+
+static void __exit nbd_cleanup(void)
+{
+ struct nbd_device *nbd;
+ LIST_HEAD(del_list);
+
+ /*
+ * Unregister netlink interface prior to waiting
+ * for the completion of netlink commands.
+ */
+ genl_unregister_family(&nbd_genl_family);
+
+ nbd_dbg_close();
+
+ mutex_lock(&nbd_index_mutex);
+ idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
+ mutex_unlock(&nbd_index_mutex);
+
+ while (!list_empty(&del_list)) {
+ nbd = list_first_entry(&del_list, struct nbd_device, list);
+ list_del_init(&nbd->list);
+ if (refcount_read(&nbd->config_refs))
+ pr_err("possibly leaking nbd_config (ref %d)\n",
+ refcount_read(&nbd->config_refs));
+ if (refcount_read(&nbd->refs) != 1)
+ pr_err("possibly leaking a device\n");
+ nbd_put(nbd);
+ }
+
+ /* Also wait for nbd_dev_remove_work() completes */
+ destroy_workqueue(nbd_del_wq);
+
+ idr_destroy(&nbd_index_idr);
+ unregister_blkdev(NBD_MAJOR, "nbd");
+}
+
+module_init(nbd_init);
+module_exit(nbd_cleanup);
+
+MODULE_DESCRIPTION("Network Block Device");
+MODULE_LICENSE("GPL");
+
+module_param(nbds_max, int, 0444);
+MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
+module_param(max_part, int, 0444);
+MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)");