/* * 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> * * This file is released under GPLv2 or later. * * (part of code stolen from loop.c) */ #include <linux/major.h> #include <linux/blkdev.h>#include <linux/module.h>#include <linux/init.h>#include <linux/sched.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/err.h>#include <linux/kernel.h>#include <linux/slab.h>#include <net/sock.h>#include <linux/net.h>#include <linux/kthread.h> #include <asm/uaccess.h>#include <asm/types.h> #include <linux/nbd.h> #define NBD_MAGIC 0x68797548 #ifdef NDEBUG#define dprintk(flags, fmt...)#else /* NDEBUG */#define dprintk(flags, fmt...) do { \ if (debugflags & (flags)) printk(KERN_DEBUG fmt); \} while (0)#define DBG_IOCTL 0x0004#define DBG_INIT 0x0010#define DBG_EXIT 0x0020#define DBG_BLKDEV 0x0100#define DBG_RX 0x0200#define DBG_TX 0x0400static unsigned int debugflags;#endif /* NDEBUG */ static unsigned int nbds_max = 16;static struct nbd_device *nbd_dev;static int max_part; /* * Use just one lock (or at most 1 per NIC). Two arguments for this: * 1. Each NIC is essentially a synchronization point for all servers * accessed through that NIC so there's no need to have more locks * than NICs anyway. * 2. More locks lead to more "Dirty cache line bouncing" which will slow * down each lock to the point where they're actually slower than just * a single lock. * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this! */static DEFINE_SPINLOCK(nbd_lock); #ifndef NDEBUGstatic const char *ioctl_cmd_to_ascii(int cmd){ switch (cmd) { case NBD_SET_SOCK: return "set-sock"; case NBD_SET_BLKSIZE: return "set-blksize"; case NBD_SET_SIZE: return "set-size"; case NBD_SET_TIMEOUT: return "set-timeout"; case NBD_SET_FLAGS: return "set-flags"; case NBD_DO_IT: return "do-it"; case NBD_CLEAR_SOCK: return "clear-sock"; case NBD_CLEAR_QUE: return "clear-que"; case NBD_PRINT_DEBUG: return "print-debug"; case NBD_SET_SIZE_BLOCKS: return "set-size-blocks"; case NBD_DISCONNECT: return "disconnect"; case BLKROSET: return "set-read-only"; case BLKFLSBUF: return "flush-buffer-cache"; } return "unknown";} 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";}#endif /* NDEBUG */ static void nbd_end_request(struct request *req){ int error = req->errors ? -EIO : 0; struct request_queue *q = req->q; unsigned long flags; dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name, req, error ? "failed" : "done"); spin_lock_irqsave(q->queue_lock, flags); __blk_end_request_all(req, error); spin_unlock_irqrestore(q->queue_lock, flags);} static void sock_shutdown(struct nbd_device *nbd, int lock){ /* Forcibly shutdown the socket causing all listeners * to error * * FIXME: This code is duplicated from sys_shutdown, but * there should be a more generic interface rather than * calling socket ops directly here */ if (lock) mutex_lock(&nbd->tx_lock); if (nbd->sock) { dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n"); kernel_sock_shutdown(nbd->sock, SHUT_RDWR); nbd->sock = NULL; } if (lock) mutex_unlock(&nbd->tx_lock);} static void nbd_xmit_timeout(unsigned long arg){ struct task_struct *task = (struct task_struct *)arg; printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n", task->comm, task->pid); force_sig(SIGKILL, task);} /* * Send or receive packet. */static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size, int msg_flags){ struct socket *sock = nbd->sock; int result; struct msghdr msg; struct kvec iov; sigset_t blocked, oldset; unsigned long pflags = current->flags; if (unlikely(!sock)) { dev_err(disk_to_dev(nbd->disk), "Attempted %s on closed socket in sock_xmit\n", (send ? "send" : "recv")); return -EINVAL; } /* Allow interception of SIGKILL only * Don't allow other signals to interrupt the transmission */ siginitsetinv(&blocked, sigmask(SIGKILL)); sigprocmask(SIG_SETMASK, &blocked, &oldset); current->flags |= PF_MEMALLOC; do { sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC; iov.iov_base = buf; iov.iov_len = size; msg.msg_name = NULL; msg.msg_namelen = 0; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_flags = msg_flags | MSG_NOSIGNAL; if (send) { struct timer_list ti; if (nbd->xmit_timeout) { init_timer(&ti); ti.function = nbd_xmit_timeout; ti.data = (unsigned long)current; ti.expires = jiffies + nbd->xmit_timeout; add_timer(&ti); } result = kernel_sendmsg(sock, &msg, &iov, 1, size); if (nbd->xmit_timeout) del_timer_sync(&ti); } else result = kernel_recvmsg(sock, &msg, &iov, 1, size, msg.msg_flags); if (signal_pending(current)) { siginfo_t info; printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n", task_pid_nr(current), current->comm, dequeue_signal_lock(current, ¤t->blocked, &info)); result = -EINTR; sock_shutdown(nbd, !send); break; } if (result <= 0) { if (result == 0) result = -EPIPE; /* short read */ break; } size -= result; buf += result; } while (size > 0); sigprocmask(SIG_SETMASK, &oldset, NULL); tsk_restore_flags(current, pflags, PF_MEMALLOC); return result;} static inline int sock_send_bvec(struct nbd_device *nbd, struct bio_vec *bvec, int flags){ int result; void *kaddr = kmap(bvec->bv_page); result = sock_xmit(nbd, 1, kaddr + bvec->bv_offset, bvec->bv_len, flags); kunmap(bvec->bv_page); return result;} /* always call with the tx_lock held */static int nbd_send_req(struct nbd_device *nbd, struct request *req){ int result, flags; struct nbd_request request; unsigned long size = blk_rq_bytes(req); request.magic = htonl(NBD_REQUEST_MAGIC); request.type = htonl(nbd_cmd(req)); if (nbd_cmd(req) == NBD_CMD_FLUSH) { /* Other values are reserved for FLUSH requests. */ request.from = 0; request.len = 0; } else { request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); request.len = htonl(size); } memcpy(request.handle, &req, sizeof(req)); dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%uB)\n", nbd->disk->disk_name, req, nbdcmd_to_ascii(nbd_cmd(req)), (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req)); result = sock_xmit(nbd, 1, &request, sizeof(request), (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0); if (result <= 0) { dev_err(disk_to_dev(nbd->disk), "Send control failed (result %d)\n", result); goto error_out; } if (nbd_cmd(req) == NBD_CMD_WRITE) { struct req_iterator iter; struct bio_vec *bvec; /* * we are really probing at internals to determine * whether to set MSG_MORE or not... */ rq_for_each_segment(bvec, req, iter) { flags = 0; if (!rq_iter_last(req, iter)) flags = MSG_MORE; dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n", nbd->disk->disk_name, req, bvec->bv_len); result = sock_send_bvec(nbd, bvec, flags); if (result <= 0) { dev_err(disk_to_dev(nbd->disk), "Send data failed (result %d)\n", result); goto error_out; } } } return 0; error_out: return -EIO;} static struct request *nbd_find_request(struct nbd_device *nbd, struct request *xreq){ struct request *req, *tmp; int err; err = wait_event_interruptible(nbd->active_wq, nbd->active_req != xreq); if (unlikely(err)) goto out; spin_lock(&nbd->queue_lock); list_for_each_entry_safe(req, tmp, &nbd->queue_head, queuelist) { if (req != xreq) continue; list_del_init(&req->queuelist); spin_unlock(&nbd->queue_lock); return req; } spin_unlock(&nbd->queue_lock); err = -ENOENT; out: return ERR_PTR(err);} static inline int sock_recv_bvec(struct nbd_device *nbd, struct bio_vec *bvec){ int result; void *kaddr = kmap(bvec->bv_page); result = sock_xmit(nbd, 0, kaddr + bvec->bv_offset, bvec->bv_len, MSG_WAITALL); kunmap(bvec->bv_page); return result;} /* NULL returned = something went wrong, inform userspace */static struct request *nbd_read_stat(struct nbd_device *nbd){ int result; struct nbd_reply reply; struct request *req; reply.magic = 0; result = sock_xmit(nbd, 0, &reply, sizeof(reply), MSG_WAITALL); if (result <= 0) { dev_err(disk_to_dev(nbd->disk), "Receive control failed (result %d)\n", result); goto harderror; } if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n", (unsigned long)ntohl(reply.magic)); result = -EPROTO; goto harderror; } req = nbd_find_request(nbd, *(struct request **)reply.handle); if (IS_ERR(req)) { result = PTR_ERR(req); if (result != -ENOENT) goto harderror; dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%p)\n", reply.handle); result = -EBADR; goto harderror; } if (ntohl(reply.error)) { dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n", ntohl(reply.error)); req->errors++; return req; } dprintk(DBG_RX, "%s: request %p: got reply\n", nbd->disk->disk_name, req); if (nbd_cmd(req) == NBD_CMD_READ) { struct req_iterator iter; struct bio_vec *bvec; rq_for_each_segment(bvec, req, iter) { result = sock_recv_bvec(nbd, bvec); if (result <= 0) { dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n", result); req->errors++; return req; } dprintk(DBG_RX, "%s: request %p: got %d bytes data\n", nbd->disk->disk_name, req, bvec->bv_len); } } return req;harderror: nbd->harderror = result; return NULL;} static ssize_t pid_show(struct device *dev, struct device_attribute *attr, char *buf){ struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%ld\n", (long) ((struct nbd_device *)disk->private_data)->pid);} static struct device_attribute pid_attr = { .attr = { .name = "pid", .mode = S_IRUGO}, .show = pid_show,}; static int nbd_do_it(struct nbd_device *nbd){ struct request *req; int ret; BUG_ON(nbd->magic != NBD_MAGIC); sk_set_memalloc(nbd->sock->sk); nbd->pid = task_pid_nr(current); ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr); if (ret) { dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n"); nbd->pid = 0; return ret; } while ((req = nbd_read_stat(nbd)) != NULL) nbd_end_request(req); device_remove_file(disk_to_dev(nbd->disk), &pid_attr); nbd->pid = 0; return 0;} static void nbd_clear_que(struct nbd_device *nbd){ struct request *req; BUG_ON(nbd->magic != NBD_MAGIC); /* * Because we have set nbd->sock to NULL under the tx_lock, all * modifications to the list must have completed by now. For * the same reason, the active_req must be NULL. * * As a consequence, we don't need to take the spin lock while * purging the list here. */ BUG_ON(nbd->sock); BUG_ON(nbd->active_req); while (!list_empty(&nbd->queue_head)) { req = list_entry(nbd->queue_head.next, struct request, queuelist); list_del_init(&req->queuelist); req->errors++; nbd_end_request(req); } while (!list_empty(&nbd->waiting_queue)) { req = list_entry(nbd->waiting_queue.next, struct request, queuelist); list_del_init(&req->queuelist); req->errors++; nbd_end_request(req); }} static void nbd_handle_req(struct nbd_device *nbd, struct request *req){ if (req->cmd_type != REQ_TYPE_FS) goto error_out; nbd_cmd(req) = NBD_CMD_READ; if (rq_data_dir(req) == WRITE) { if ((req->cmd_flags & REQ_DISCARD)) { WARN_ON(!(nbd->flags & NBD_FLAG_SEND_TRIM)); nbd_cmd(req) = NBD_CMD_TRIM; } else nbd_cmd(req) = NBD_CMD_WRITE; if (nbd->flags & NBD_FLAG_READ_ONLY) { dev_err(disk_to_dev(nbd->disk), "Write on read-only\n"); goto error_out; } } if (req->cmd_flags & REQ_FLUSH) { BUG_ON(unlikely(blk_rq_sectors(req))); nbd_cmd(req) = NBD_CMD_FLUSH; } req->errors = 0; mutex_lock(&nbd->tx_lock);Lines 1–500 of 938. 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/* * 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> * * This file is released under GPLv2 or later. * * (part of code stolen from loop.c) */ #include <linux/major.h> #include <linux/blkdev.h> #include <linux/module.h> #include <linux/init.h> #include <linux/sched.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/err.h> #include <linux/kernel.h> #include <linux/slab.h> #include <net/sock.h> #include <linux/net.h> #include <linux/kthread.h> #include <asm/uaccess.h> #include <asm/types.h> #include <linux/nbd.h> #define NBD_MAGIC 0x68797548 #ifdef NDEBUG #define dprintk(flags, fmt...) #else /* NDEBUG */ #define dprintk(flags, fmt...) do { \ if (debugflags & (flags)) printk(KERN_DEBUG fmt); \ } while (0) #define DBG_IOCTL 0x0004 #define DBG_INIT 0x0010 #define DBG_EXIT 0x0020 #define DBG_BLKDEV 0x0100 #define DBG_RX 0x0200 #define DBG_TX 0x0400 static unsigned int debugflags; #endif /* NDEBUG */ static unsigned int nbds_max = 16; static struct nbd_device *nbd_dev; static int max_part; /* * Use just one lock (or at most 1 per NIC). Two arguments for this: * 1. Each NIC is essentially a synchronization point for all servers * accessed through that NIC so there's no need to have more locks * than NICs anyway. * 2. More locks lead to more "Dirty cache line bouncing" which will slow * down each lock to the point where they're actually slower than just * a single lock. * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this! */ static DEFINE_SPINLOCK(nbd_lock); #ifndef NDEBUG static const char *ioctl_cmd_to_ascii(int cmd) { switch (cmd) { case NBD_SET_SOCK: return "set-sock"; case NBD_SET_BLKSIZE: return "set-blksize"; case NBD_SET_SIZE: return "set-size"; case NBD_SET_TIMEOUT: return "set-timeout"; case NBD_SET_FLAGS: return "set-flags"; case NBD_DO_IT: return "do-it"; case NBD_CLEAR_SOCK: return "clear-sock"; case NBD_CLEAR_QUE: return "clear-que"; case NBD_PRINT_DEBUG: return "print-debug"; case NBD_SET_SIZE_BLOCKS: return "set-size-blocks"; case NBD_DISCONNECT: return "disconnect"; case BLKROSET: return "set-read-only"; case BLKFLSBUF: return "flush-buffer-cache"; } return "unknown"; } 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"; } #endif /* NDEBUG */ static void nbd_end_request(struct request *req) { int error = req->errors ? -EIO : 0; struct request_queue *q = req->q; unsigned long flags; dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name, req, error ? "failed" : "done"); spin_lock_irqsave(q->queue_lock, flags); __blk_end_request_all(req, error); spin_unlock_irqrestore(q->queue_lock, flags); } static void sock_shutdown(struct nbd_device *nbd, int lock) { /* Forcibly shutdown the socket causing all listeners * to error * * FIXME: This code is duplicated from sys_shutdown, but * there should be a more generic interface rather than * calling socket ops directly here */ if (lock) mutex_lock(&nbd->tx_lock); if (nbd->sock) { dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n"); kernel_sock_shutdown(nbd->sock, SHUT_RDWR); nbd->sock = NULL; } if (lock) mutex_unlock(&nbd->tx_lock); } static void nbd_xmit_timeout(unsigned long arg) { struct task_struct *task = (struct task_struct *)arg; printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n", task->comm, task->pid); force_sig(SIGKILL, task); } /* * Send or receive packet. */ static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size, int msg_flags) { struct socket *sock = nbd->sock; int result; struct msghdr msg; struct kvec iov; sigset_t blocked, oldset; unsigned long pflags = current->flags; if (unlikely(!sock)) { dev_err(disk_to_dev(nbd->disk), "Attempted %s on closed socket in sock_xmit\n", (send ? "send" : "recv")); return -EINVAL; } /* Allow interception of SIGKILL only * Don't allow other signals to interrupt the transmission */ siginitsetinv(&blocked, sigmask(SIGKILL)); sigprocmask(SIG_SETMASK, &blocked, &oldset); current->flags |= PF_MEMALLOC; do { sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC; iov.iov_base = buf; iov.iov_len = size; msg.msg_name = NULL; msg.msg_namelen = 0; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_flags = msg_flags | MSG_NOSIGNAL; if (send) { struct timer_list ti; if (nbd->xmit_timeout) { init_timer(&ti); ti.function = nbd_xmit_timeout; ti.data = (unsigned long)current; ti.expires = jiffies + nbd->xmit_timeout; add_timer(&ti); } result = kernel_sendmsg(sock, &msg, &iov, 1, size); if (nbd->xmit_timeout) del_timer_sync(&ti); } else result = kernel_recvmsg(sock, &msg, &iov, 1, size, msg.msg_flags); if (signal_pending(current)) { siginfo_t info; printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n", task_pid_nr(current), current->comm, dequeue_signal_lock(current, ¤t->blocked, &info)); result = -EINTR; sock_shutdown(nbd, !send); break; } if (result <= 0) { if (result == 0) result = -EPIPE; /* short read */ break; } size -= result; buf += result; } while (size > 0); sigprocmask(SIG_SETMASK, &oldset, NULL); tsk_restore_flags(current, pflags, PF_MEMALLOC); return result; } static inline int sock_send_bvec(struct nbd_device *nbd, struct bio_vec *bvec, int flags) { int result; void *kaddr = kmap(bvec->bv_page); result = sock_xmit(nbd, 1, kaddr + bvec->bv_offset, bvec->bv_len, flags); kunmap(bvec->bv_page); return result; } /* always call with the tx_lock held */ static int nbd_send_req(struct nbd_device *nbd, struct request *req) { int result, flags; struct nbd_request request; unsigned long size = blk_rq_bytes(req); request.magic = htonl(NBD_REQUEST_MAGIC); request.type = htonl(nbd_cmd(req)); if (nbd_cmd(req) == NBD_CMD_FLUSH) { /* Other values are reserved for FLUSH requests. */ request.from = 0; request.len = 0; } else { request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); request.len = htonl(size); } memcpy(request.handle, &req, sizeof(req)); dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%uB)\n", nbd->disk->disk_name, req, nbdcmd_to_ascii(nbd_cmd(req)), (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req)); result = sock_xmit(nbd, 1, &request, sizeof(request), (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0); if (result <= 0) { dev_err(disk_to_dev(nbd->disk), "Send control failed (result %d)\n", result); goto error_out; } if (nbd_cmd(req) == NBD_CMD_WRITE) { struct req_iterator iter; struct bio_vec *bvec; /* * we are really probing at internals to determine * whether to set MSG_MORE or not... */ rq_for_each_segment(bvec, req, iter) { flags = 0; if (!rq_iter_last(req, iter)) flags = MSG_MORE; dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n", nbd->disk->disk_name, req, bvec->bv_len); result = sock_send_bvec(nbd, bvec, flags); if (result <= 0) { dev_err(disk_to_dev(nbd->disk), "Send data failed (result %d)\n", result); goto error_out; } } } return 0; error_out: return -EIO; } static struct request *nbd_find_request(struct nbd_device *nbd, struct request *xreq) { struct request *req, *tmp; int err; err = wait_event_interruptible(nbd->active_wq, nbd->active_req != xreq); if (unlikely(err)) goto out; spin_lock(&nbd->queue_lock); list_for_each_entry_safe(req, tmp, &nbd->queue_head, queuelist) { if (req != xreq) continue; list_del_init(&req->queuelist); spin_unlock(&nbd->queue_lock); return req; } spin_unlock(&nbd->queue_lock); err = -ENOENT; out: return ERR_PTR(err); } static inline int sock_recv_bvec(struct nbd_device *nbd, struct bio_vec *bvec) { int result; void *kaddr = kmap(bvec->bv_page); result = sock_xmit(nbd, 0, kaddr + bvec->bv_offset, bvec->bv_len, MSG_WAITALL); kunmap(bvec->bv_page); return result; } /* NULL returned = something went wrong, inform userspace */ static struct request *nbd_read_stat(struct nbd_device *nbd) { int result; struct nbd_reply reply; struct request *req; reply.magic = 0; result = sock_xmit(nbd, 0, &reply, sizeof(reply), MSG_WAITALL); if (result <= 0) { dev_err(disk_to_dev(nbd->disk), "Receive control failed (result %d)\n", result); goto harderror; } if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n", (unsigned long)ntohl(reply.magic)); result = -EPROTO; goto harderror; } req = nbd_find_request(nbd, *(struct request **)reply.handle); if (IS_ERR(req)) { result = PTR_ERR(req); if (result != -ENOENT) goto harderror; dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%p)\n", reply.handle); result = -EBADR; goto harderror; } if (ntohl(reply.error)) { dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n", ntohl(reply.error)); req->errors++; return req; } dprintk(DBG_RX, "%s: request %p: got reply\n", nbd->disk->disk_name, req); if (nbd_cmd(req) == NBD_CMD_READ) { struct req_iterator iter; struct bio_vec *bvec; rq_for_each_segment(bvec, req, iter) { result = sock_recv_bvec(nbd, bvec); if (result <= 0) { dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n", result); req->errors++; return req; } dprintk(DBG_RX, "%s: request %p: got %d bytes data\n", nbd->disk->disk_name, req, bvec->bv_len); } } return req; harderror: nbd->harderror = result; return NULL; } static ssize_t pid_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%ld\n", (long) ((struct nbd_device *)disk->private_data)->pid); } static struct device_attribute pid_attr = { .attr = { .name = "pid", .mode = S_IRUGO}, .show = pid_show, }; static int nbd_do_it(struct nbd_device *nbd) { struct request *req; int ret; BUG_ON(nbd->magic != NBD_MAGIC); sk_set_memalloc(nbd->sock->sk); nbd->pid = task_pid_nr(current); ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr); if (ret) { dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n"); nbd->pid = 0; return ret; } while ((req = nbd_read_stat(nbd)) != NULL) nbd_end_request(req); device_remove_file(disk_to_dev(nbd->disk), &pid_attr); nbd->pid = 0; return 0; } static void nbd_clear_que(struct nbd_device *nbd) { struct request *req; BUG_ON(nbd->magic != NBD_MAGIC); /* * Because we have set nbd->sock to NULL under the tx_lock, all * modifications to the list must have completed by now. For * the same reason, the active_req must be NULL. * * As a consequence, we don't need to take the spin lock while * purging the list here. */ BUG_ON(nbd->sock); BUG_ON(nbd->active_req); while (!list_empty(&nbd->queue_head)) { req = list_entry(nbd->queue_head.next, struct request, queuelist); list_del_init(&req->queuelist); req->errors++; nbd_end_request(req); } while (!list_empty(&nbd->waiting_queue)) { req = list_entry(nbd->waiting_queue.next, struct request, queuelist); list_del_init(&req->queuelist); req->errors++; nbd_end_request(req); } } static void nbd_handle_req(struct nbd_device *nbd, struct request *req) { if (req->cmd_type != REQ_TYPE_FS) goto error_out; nbd_cmd(req) = NBD_CMD_READ; if (rq_data_dir(req) == WRITE) { if ((req->cmd_flags & REQ_DISCARD)) { WARN_ON(!(nbd->flags & NBD_FLAG_SEND_TRIM)); nbd_cmd(req) = NBD_CMD_TRIM; } else nbd_cmd(req) = NBD_CMD_WRITE; if (nbd->flags & NBD_FLAG_READ_ONLY) { dev_err(disk_to_dev(nbd->disk), "Write on read-only\n"); goto error_out; } } if (req->cmd_flags & REQ_FLUSH) { BUG_ON(unlikely(blk_rq_sectors(req))); nbd_cmd(req) = NBD_CMD_FLUSH; } req->errors = 0; mutex_lock(&nbd->tx_lock);