// 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 <[email protected]> * Parts copyright 2001 Steven Whitehouse <[email protected]> * * (part of code stolen from loop.c) */ #define pr_fmt(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 = …; struct nbd_sock { … }; struct recv_thread_args { … }; struct link_dead_args { … }; #define NBD_RT_TIMEDOUT … #define NBD_RT_DISCONNECT_REQUESTED … #define NBD_RT_DISCONNECTED … #define NBD_RT_HAS_PID_FILE … #define NBD_RT_HAS_CONFIG_REF … #define NBD_RT_BOUND … #define NBD_RT_DISCONNECT_ON_CLOSE … #define NBD_RT_HAS_BACKEND_FILE … #define NBD_DESTROY_ON_DISCONNECT … #define NBD_DISCONNECT_REQUESTED … struct nbd_config { … }; static inline unsigned int nbd_blksize(struct nbd_config *config) { … } struct nbd_device { … }; #define NBD_CMD_REQUEUED … /* * 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 … struct nbd_cmd { … }; #if IS_ENABLED(CONFIG_DEBUG_FS) static struct dentry *nbd_dbg_dir; #endif #define nbd_name(nbd) … #define NBD_DEF_BLKSIZE_BITS … static unsigned int nbds_max = …; static int max_part = …; 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) { … } static void nbd_requeue_cmd(struct nbd_cmd *cmd) { … } #define NBD_COOKIE_BITS … static u64 nbd_cmd_handle(struct nbd_cmd *cmd) { … } static u32 nbd_handle_to_tag(u64 handle) { … } static u32 nbd_handle_to_cookie(u64 handle) { … } static const char *nbdcmd_to_ascii(int cmd) { … } static ssize_t pid_show(struct device *dev, struct device_attribute *attr, char *buf) { … } static const struct device_attribute pid_attr = …; static ssize_t backend_show(struct device *dev, struct device_attribute *attr, char *buf) { … } static const struct device_attribute backend_attr = …; static void nbd_dev_remove(struct nbd_device *nbd) { … } static void nbd_dev_remove_work(struct work_struct *work) { … } static void nbd_put(struct nbd_device *nbd) { … } static int nbd_disconnected(struct nbd_config *config) { … } static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock, int notify) { … } static int __nbd_set_size(struct nbd_device *nbd, loff_t bytesize, loff_t blksize) { … } static int nbd_set_size(struct nbd_device *nbd, loff_t bytesize, loff_t blksize) { … } static void nbd_complete_rq(struct request *req) { … } /* * Forcibly shutdown the socket causing all listeners to error */ static void sock_shutdown(struct nbd_device *nbd) { … } static u32 req_to_nbd_cmd_type(struct request *req) { … } static struct nbd_config *nbd_get_config_unlocked(struct nbd_device *nbd) { … } static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req) { … } static int __sock_xmit(struct nbd_device *nbd, struct socket *sock, int send, struct iov_iter *iter, int msg_flags, int *sent) { … } /* * 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) { … } /* * 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) { … } /* * Returns BLK_STS_RESOURCE if the caller should retry after a delay. * Returns BLK_STS_IOERR if sending failed. */ static blk_status_t nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) { … } static int nbd_read_reply(struct nbd_device *nbd, struct socket *sock, struct nbd_reply *reply) { … } /* NULL returned = something went wrong, inform userspace */ static struct nbd_cmd *nbd_handle_reply(struct nbd_device *nbd, int index, struct nbd_reply *reply) { … } static void recv_work(struct work_struct *work) { … } static bool nbd_clear_req(struct request *req, void *data) { … } static void nbd_clear_que(struct nbd_device *nbd) { … } static int find_fallback(struct nbd_device *nbd, int index) { … } static int wait_for_reconnect(struct nbd_device *nbd) { … } static blk_status_t nbd_handle_cmd(struct nbd_cmd *cmd, int index) { … } static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *bd) { … } static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd, int *err) { … } static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg, bool netlink) { … } static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg) { … } static void nbd_bdev_reset(struct nbd_device *nbd) { … } static void nbd_parse_flags(struct nbd_device *nbd) { … } static void send_disconnects(struct nbd_device *nbd) { … } static int nbd_disconnect(struct nbd_device *nbd) { … } static void nbd_clear_sock(struct nbd_device *nbd) { … } static void nbd_config_put(struct nbd_device *nbd) { … } static int nbd_start_device(struct nbd_device *nbd) { … } static int nbd_start_device_ioctl(struct nbd_device *nbd) { … } static void nbd_clear_sock_ioctl(struct nbd_device *nbd) { … } static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout) { … } /* 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) { … } static int nbd_ioctl(struct block_device *bdev, blk_mode_t mode, unsigned int cmd, unsigned long arg) { … } static int nbd_alloc_and_init_config(struct nbd_device *nbd) { … } static int nbd_open(struct gendisk *disk, blk_mode_t mode) { … } static void nbd_release(struct gendisk *disk) { … } static void nbd_free_disk(struct gendisk *disk) { … } static const struct block_device_operations nbd_fops = …; #if IS_ENABLED(CONFIG_DEBUG_FS) static int nbd_dbg_tasks_show(struct seq_file *s, void *unused) { … } DEFINE_SHOW_ATTRIBUTE(…); static int nbd_dbg_flags_show(struct seq_file *s, void *unused) { … } DEFINE_SHOW_ATTRIBUTE(…); static int nbd_dev_dbg_init(struct nbd_device *nbd) { … } static void nbd_dev_dbg_close(struct nbd_device *nbd) { … } static int nbd_dbg_init(void) { … } static void nbd_dbg_close(void) { … } #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) { … } static const struct blk_mq_ops nbd_mq_ops = …; static struct nbd_device *nbd_dev_add(int index, unsigned int refs) { … } static struct nbd_device *nbd_find_get_unused(void) { … } /* Netlink interface. */ static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = …; static const struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = …; /* 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] = …; static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd) { … } static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info) { … } static void nbd_disconnect_and_put(struct nbd_device *nbd) { … } static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info) { … } static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info) { … } static const struct genl_small_ops nbd_connect_genl_ops[] = …; static const struct genl_multicast_group nbd_mcast_grps[] = …; static struct genl_family nbd_genl_family __ro_after_init = …; MODULE_ALIAS_GENL_FAMILY(…); static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply) { … } static int status_cb(int id, void *ptr, void *data) { … } static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info) { … } static void nbd_connect_reply(struct genl_info *info, int index) { … } static void nbd_mcast_index(int index) { … } static void nbd_dead_link_work(struct work_struct *work) { … } static int __init nbd_init(void) { … } static int nbd_exit_cb(int id, void *ptr, void *data) { … } static void __exit nbd_cleanup(void) { … } module_init(…) …; module_exit(nbd_cleanup); MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …; module_param(nbds_max, int, 0444); MODULE_PARM_DESC(…) …; module_param(max_part, int, 0444); MODULE_PARM_DESC(…) …;
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