linux_dsm_epyc7002/drivers/block/nbd.c
Josef Bacik d61b7f972d nbd: only set MSG_MORE when we have more to send
A user noticed that write performance was horrible over loopback and we
traced it to an inversion of when we need to set MSG_MORE.  It should be
set when we have more bvec's to send, not when we are on the last bvec.
This patch made the test go from 20 iops to 78k iops.

Signed-off-by: Josef Bacik <jbacik@fb.com>
Fixes: 429a787be6 ("nbd: fix use-after-free of rq/bio in the xmit path")
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-19 14:31:50 -07:00

1154 lines
27 KiB
C

/*
* 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 <linux/types.h>
#include <linux/debugfs.h>
#include <linux/blk-mq.h>
#include <linux/uaccess.h>
#include <asm/types.h>
#include <linux/nbd.h>
struct nbd_sock {
struct socket *sock;
struct mutex tx_lock;
};
#define NBD_TIMEDOUT 0
#define NBD_DISCONNECT_REQUESTED 1
#define NBD_DISCONNECTED 2
#define NBD_RUNNING 3
struct nbd_device {
u32 flags;
unsigned long runtime_flags;
struct nbd_sock **socks;
int magic;
struct blk_mq_tag_set tag_set;
struct mutex config_lock;
struct gendisk *disk;
int num_connections;
atomic_t recv_threads;
wait_queue_head_t recv_wq;
loff_t blksize;
loff_t bytesize;
struct task_struct *task_recv;
struct task_struct *task_setup;
#if IS_ENABLED(CONFIG_DEBUG_FS)
struct dentry *dbg_dir;
#endif
};
struct nbd_cmd {
struct nbd_device *nbd;
struct completion send_complete;
};
#if IS_ENABLED(CONFIG_DEBUG_FS)
static struct dentry *nbd_dbg_dir;
#endif
#define nbd_name(nbd) ((nbd)->disk->disk_name)
#define NBD_MAGIC 0x68797548
static unsigned int nbds_max = 16;
static struct nbd_device *nbd_dev;
static int max_part;
static inline struct device *nbd_to_dev(struct nbd_device *nbd)
{
return disk_to_dev(nbd->disk);
}
static bool nbd_is_connected(struct nbd_device *nbd)
{
return !!nbd->task_recv;
}
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 int nbd_size_clear(struct nbd_device *nbd, struct block_device *bdev)
{
bdev->bd_inode->i_size = 0;
set_capacity(nbd->disk, 0);
kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
return 0;
}
static void nbd_size_update(struct nbd_device *nbd, struct block_device *bdev)
{
if (!nbd_is_connected(nbd))
return;
bdev->bd_inode->i_size = nbd->bytesize;
set_capacity(nbd->disk, nbd->bytesize >> 9);
kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
}
static int nbd_size_set(struct nbd_device *nbd, struct block_device *bdev,
loff_t blocksize, loff_t nr_blocks)
{
int ret;
ret = set_blocksize(bdev, blocksize);
if (ret)
return ret;
nbd->blksize = blocksize;
nbd->bytesize = blocksize * nr_blocks;
nbd_size_update(nbd, bdev);
return 0;
}
static void nbd_end_request(struct nbd_cmd *cmd)
{
struct nbd_device *nbd = cmd->nbd;
struct request *req = blk_mq_rq_from_pdu(cmd);
int error = req->errors ? -EIO : 0;
dev_dbg(nbd_to_dev(nbd), "request %p: %s\n", cmd,
error ? "failed" : "done");
blk_mq_complete_request(req, error);
}
/*
* Forcibly shutdown the socket causing all listeners to error
*/
static void sock_shutdown(struct nbd_device *nbd)
{
int i;
if (nbd->num_connections == 0)
return;
if (test_and_set_bit(NBD_DISCONNECTED, &nbd->runtime_flags))
return;
for (i = 0; i < nbd->num_connections; i++) {
struct nbd_sock *nsock = nbd->socks[i];
mutex_lock(&nsock->tx_lock);
kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
mutex_unlock(&nsock->tx_lock);
}
dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
}
static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
bool reserved)
{
struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
struct nbd_device *nbd = cmd->nbd;
dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down connection\n");
set_bit(NBD_TIMEDOUT, &nbd->runtime_flags);
req->errors++;
/*
* If our disconnect packet times out then we're already holding the
* config_lock and could deadlock here, so just set an error and return,
* we'll handle shutting everything down later.
*/
if (req->cmd_type == REQ_TYPE_DRV_PRIV)
return BLK_EH_HANDLED;
mutex_lock(&nbd->config_lock);
sock_shutdown(nbd);
mutex_unlock(&nbd->config_lock);
return BLK_EH_HANDLED;
}
/*
* Send or receive packet.
*/
static int sock_xmit(struct nbd_device *nbd, int index, int send, void *buf,
int size, int msg_flags)
{
struct socket *sock = nbd->socks[index]->sock;
int result;
struct msghdr msg;
struct kvec iov;
unsigned long pflags = current->flags;
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;
}
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)
result = kernel_sendmsg(sock, &msg, &iov, 1, size);
else
result = kernel_recvmsg(sock, &msg, &iov, 1, size,
msg.msg_flags);
if (result <= 0) {
if (result == 0)
result = -EPIPE; /* short read */
break;
}
size -= result;
buf += result;
} while (size > 0);
tsk_restore_flags(current, pflags, PF_MEMALLOC);
return result;
}
static inline int sock_send_bvec(struct nbd_device *nbd, int index,
struct bio_vec *bvec, int flags)
{
int result;
void *kaddr = kmap(bvec->bv_page);
result = sock_xmit(nbd, index, 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_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
{
struct request *req = blk_mq_rq_from_pdu(cmd);
int result;
struct nbd_request request;
unsigned long size = blk_rq_bytes(req);
struct bio *bio;
u32 type;
u32 tag = blk_mq_unique_tag(req);
if (req_op(req) == REQ_OP_DISCARD)
type = NBD_CMD_TRIM;
else if (req_op(req) == REQ_OP_FLUSH)
type = NBD_CMD_FLUSH;
else if (rq_data_dir(req) == WRITE)
type = NBD_CMD_WRITE;
else
type = NBD_CMD_READ;
memset(&request, 0, sizeof(request));
request.magic = htonl(NBD_REQUEST_MAGIC);
request.type = htonl(type);
if (type != NBD_CMD_FLUSH) {
request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
request.len = htonl(size);
}
memcpy(request.handle, &tag, sizeof(tag));
dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
cmd, nbdcmd_to_ascii(type),
(unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
result = sock_xmit(nbd, index, 1, &request, sizeof(request),
(type == NBD_CMD_WRITE) ? MSG_MORE : 0);
if (result <= 0) {
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Send control failed (result %d)\n", result);
return -EIO;
}
if (type != NBD_CMD_WRITE)
return 0;
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",
cmd, bvec.bv_len);
result = sock_send_bvec(nbd, index, &bvec, flags);
if (result <= 0) {
dev_err(disk_to_dev(nbd->disk),
"Send data failed (result %d)\n",
result);
return -EIO;
}
/*
* 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;
}
return 0;
}
static inline int sock_recv_bvec(struct nbd_device *nbd, int index,
struct bio_vec *bvec)
{
int result;
void *kaddr = kmap(bvec->bv_page);
result = sock_xmit(nbd, index, 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 nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
{
int result;
struct nbd_reply reply;
struct nbd_cmd *cmd;
struct request *req = NULL;
u16 hwq;
u32 tag;
reply.magic = 0;
result = sock_xmit(nbd, index, 0, &reply, sizeof(reply), MSG_WAITALL);
if (result <= 0) {
if (!test_bit(NBD_DISCONNECTED, &nbd->runtime_flags) &&
!test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags))
dev_err(disk_to_dev(nbd->disk),
"Receive control failed (result %d)\n", result);
return ERR_PTR(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 ERR_PTR(-EPROTO);
}
memcpy(&tag, reply.handle, sizeof(u32));
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);
}
cmd = blk_mq_rq_to_pdu(req);
if (ntohl(reply.error)) {
dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
ntohl(reply.error));
req->errors++;
return cmd;
}
dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", cmd);
if (rq_data_dir(req) != WRITE) {
struct req_iterator iter;
struct bio_vec bvec;
rq_for_each_segment(bvec, req, iter) {
result = sock_recv_bvec(nbd, index, &bvec);
if (result <= 0) {
dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
result);
req->errors++;
return cmd;
}
dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
cmd, bvec.bv_len);
}
} else {
/* See the comment in nbd_queue_rq. */
wait_for_completion(&cmd->send_complete);
}
return cmd;
}
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", task_pid_nr(nbd->task_recv));
}
static struct device_attribute pid_attr = {
.attr = { .name = "pid", .mode = S_IRUGO},
.show = pid_show,
};
struct recv_thread_args {
struct work_struct work;
struct nbd_device *nbd;
int index;
};
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_cmd *cmd;
int ret = 0;
BUG_ON(nbd->magic != NBD_MAGIC);
while (1) {
cmd = nbd_read_stat(nbd, args->index);
if (IS_ERR(cmd)) {
ret = PTR_ERR(cmd);
break;
}
nbd_end_request(cmd);
}
/*
* We got an error, shut everybody down if this wasn't the result of a
* disconnect request.
*/
if (ret && !test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags))
sock_shutdown(nbd);
atomic_dec(&nbd->recv_threads);
wake_up(&nbd->recv_wq);
}
static void nbd_clear_req(struct request *req, void *data, bool reserved)
{
struct nbd_cmd *cmd;
if (!blk_mq_request_started(req))
return;
cmd = blk_mq_rq_to_pdu(req);
req->errors++;
nbd_end_request(cmd);
}
static void nbd_clear_que(struct nbd_device *nbd)
{
BUG_ON(nbd->magic != NBD_MAGIC);
blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
}
static void 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_sock *nsock;
if (index >= nbd->num_connections) {
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Attempted send on invalid socket\n");
goto error_out;
}
if (test_bit(NBD_DISCONNECTED, &nbd->runtime_flags)) {
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Attempted send on closed socket\n");
goto error_out;
}
if (req->cmd_type != REQ_TYPE_FS &&
req->cmd_type != REQ_TYPE_DRV_PRIV)
goto error_out;
if (req->cmd_type == REQ_TYPE_FS &&
rq_data_dir(req) == WRITE &&
(nbd->flags & NBD_FLAG_READ_ONLY)) {
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Write on read-only\n");
goto error_out;
}
req->errors = 0;
nsock = nbd->socks[index];
mutex_lock(&nsock->tx_lock);
if (unlikely(!nsock->sock)) {
mutex_unlock(&nsock->tx_lock);
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Attempted send on closed socket\n");
goto error_out;
}
if (nbd_send_cmd(nbd, cmd, index) != 0) {
dev_err_ratelimited(disk_to_dev(nbd->disk),
"Request send failed\n");
req->errors++;
nbd_end_request(cmd);
}
mutex_unlock(&nsock->tx_lock);
return;
error_out:
req->errors++;
nbd_end_request(cmd);
}
static int 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);
/*
* 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.
*/
init_completion(&cmd->send_complete);
blk_mq_start_request(bd->rq);
nbd_handle_cmd(cmd, hctx->queue_num);
complete(&cmd->send_complete);
return BLK_MQ_RQ_QUEUE_OK;
}
static int nbd_add_socket(struct nbd_device *nbd, struct socket *sock)
{
struct nbd_sock **socks;
struct nbd_sock *nsock;
if (!nbd->task_setup)
nbd->task_setup = current;
if (nbd->task_setup != current) {
dev_err(disk_to_dev(nbd->disk),
"Device being setup by another task");
return -EINVAL;
}
socks = krealloc(nbd->socks, (nbd->num_connections + 1) *
sizeof(struct nbd_sock *), GFP_KERNEL);
if (!socks)
return -ENOMEM;
nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL);
if (!nsock)
return -ENOMEM;
nbd->socks = socks;
mutex_init(&nsock->tx_lock);
nsock->sock = sock;
socks[nbd->num_connections++] = nsock;
return 0;
}
/* Reset all properties of an NBD device */
static void nbd_reset(struct nbd_device *nbd)
{
int i;
for (i = 0; i < nbd->num_connections; i++)
kfree(nbd->socks[i]);
kfree(nbd->socks);
nbd->socks = NULL;
nbd->runtime_flags = 0;
nbd->blksize = 1024;
nbd->bytesize = 0;
set_capacity(nbd->disk, 0);
nbd->flags = 0;
nbd->tag_set.timeout = 0;
nbd->num_connections = 0;
nbd->task_setup = NULL;
queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
}
static void nbd_bdev_reset(struct block_device *bdev)
{
set_device_ro(bdev, false);
bdev->bd_inode->i_size = 0;
if (max_part > 0) {
blkdev_reread_part(bdev);
bdev->bd_invalidated = 1;
}
}
static void nbd_parse_flags(struct nbd_device *nbd, struct block_device *bdev)
{
if (nbd->flags & NBD_FLAG_READ_ONLY)
set_device_ro(bdev, true);
if (nbd->flags & NBD_FLAG_SEND_TRIM)
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
if (nbd->flags & NBD_FLAG_SEND_FLUSH)
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_request request = {};
int i, ret;
request.magic = htonl(NBD_REQUEST_MAGIC);
request.type = htonl(NBD_CMD_DISC);
for (i = 0; i < nbd->num_connections; i++) {
ret = sock_xmit(nbd, i, 1, &request, sizeof(request), 0);
if (ret <= 0)
dev_err(disk_to_dev(nbd->disk),
"Send disconnect failed %d\n", ret);
}
}
static int nbd_dev_dbg_init(struct nbd_device *nbd);
static void nbd_dev_dbg_close(struct nbd_device *nbd);
/* 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)
{
switch (cmd) {
case NBD_DISCONNECT: {
dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
if (!nbd->socks)
return -EINVAL;
mutex_unlock(&nbd->config_lock);
fsync_bdev(bdev);
mutex_lock(&nbd->config_lock);
/* Check again after getting mutex back. */
if (!nbd->socks)
return -EINVAL;
if (!test_and_set_bit(NBD_DISCONNECT_REQUESTED,
&nbd->runtime_flags))
send_disconnects(nbd);
return 0;
}
case NBD_CLEAR_SOCK:
sock_shutdown(nbd);
nbd_clear_que(nbd);
kill_bdev(bdev);
nbd_bdev_reset(bdev);
/*
* We want to give the run thread a chance to wait for everybody
* to clean up and then do it's own cleanup.
*/
if (!test_bit(NBD_RUNNING, &nbd->runtime_flags)) {
int i;
for (i = 0; i < nbd->num_connections; i++)
kfree(nbd->socks[i]);
kfree(nbd->socks);
nbd->socks = NULL;
nbd->num_connections = 0;
nbd->task_setup = NULL;
}
return 0;
case NBD_SET_SOCK: {
int err;
struct socket *sock = sockfd_lookup(arg, &err);
if (!sock)
return err;
err = nbd_add_socket(nbd, sock);
if (!err && max_part)
bdev->bd_invalidated = 1;
return err;
}
case NBD_SET_BLKSIZE: {
loff_t bsize = div_s64(nbd->bytesize, arg);
return nbd_size_set(nbd, bdev, arg, bsize);
}
case NBD_SET_SIZE:
return nbd_size_set(nbd, bdev, nbd->blksize,
div_s64(arg, nbd->blksize));
case NBD_SET_SIZE_BLOCKS:
return nbd_size_set(nbd, bdev, nbd->blksize, arg);
case NBD_SET_TIMEOUT:
nbd->tag_set.timeout = arg * HZ;
return 0;
case NBD_SET_FLAGS:
nbd->flags = arg;
return 0;
case NBD_DO_IT: {
struct recv_thread_args *args;
int num_connections = nbd->num_connections;
int error = 0, i;
if (nbd->task_recv)
return -EBUSY;
if (!nbd->socks)
return -EINVAL;
if (num_connections > 1 &&
!(nbd->flags & NBD_FLAG_CAN_MULTI_CONN)) {
dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
error = -EINVAL;
goto out_err;
}
set_bit(NBD_RUNNING, &nbd->runtime_flags);
blk_mq_update_nr_hw_queues(&nbd->tag_set, nbd->num_connections);
args = kcalloc(num_connections, sizeof(*args), GFP_KERNEL);
if (!args) {
error = -ENOMEM;
goto out_err;
}
nbd->task_recv = current;
mutex_unlock(&nbd->config_lock);
nbd_parse_flags(nbd, bdev);
error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
if (error) {
dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
goto out_recv;
}
nbd_size_update(nbd, bdev);
nbd_dev_dbg_init(nbd);
for (i = 0; i < num_connections; i++) {
sk_set_memalloc(nbd->socks[i]->sock->sk);
atomic_inc(&nbd->recv_threads);
INIT_WORK(&args[i].work, recv_work);
args[i].nbd = nbd;
args[i].index = i;
queue_work(system_long_wq, &args[i].work);
}
wait_event_interruptible(nbd->recv_wq,
atomic_read(&nbd->recv_threads) == 0);
for (i = 0; i < num_connections; i++)
flush_work(&args[i].work);
nbd_dev_dbg_close(nbd);
nbd_size_clear(nbd, bdev);
device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
out_recv:
mutex_lock(&nbd->config_lock);
nbd->task_recv = NULL;
out_err:
sock_shutdown(nbd);
nbd_clear_que(nbd);
kill_bdev(bdev);
nbd_bdev_reset(bdev);
/* user requested, ignore socket errors */
if (test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags))
error = 0;
if (test_bit(NBD_TIMEDOUT, &nbd->runtime_flags))
error = -ETIMEDOUT;
nbd_reset(nbd);
return error;
}
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, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
struct nbd_device *nbd = bdev->bd_disk->private_data;
int error;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
BUG_ON(nbd->magic != NBD_MAGIC);
mutex_lock(&nbd->config_lock);
error = __nbd_ioctl(bdev, nbd, cmd, arg);
mutex_unlock(&nbd->config_lock);
return error;
}
static const struct block_device_operations nbd_fops =
{
.owner = THIS_MODULE,
.ioctl = nbd_ioctl,
.compat_ioctl = nbd_ioctl,
};
#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->task_recv)
seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
return 0;
}
static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
{
return single_open(file, nbd_dbg_tasks_show, inode->i_private);
}
static const struct file_operations nbd_dbg_tasks_ops = {
.open = nbd_dbg_tasks_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
{
struct nbd_device *nbd = s->private;
u32 flags = nbd->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_TRIM)
seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
return 0;
}
static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
{
return single_open(file, nbd_dbg_flags_show, inode->i_private);
}
static const struct file_operations nbd_dbg_flags_ops = {
.open = nbd_dbg_flags_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int nbd_dev_dbg_init(struct nbd_device *nbd)
{
struct dentry *dir;
if (!nbd_dbg_dir)
return -EIO;
dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
if (!dir) {
dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
nbd_name(nbd));
return -EIO;
}
nbd->dbg_dir = dir;
debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
debugfs_create_u64("size_bytes", 0444, dir, &nbd->bytesize);
debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
debugfs_create_u64("blocksize", 0444, dir, &nbd->blksize);
debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
return 0;
}
static void nbd_dev_dbg_close(struct nbd_device *nbd)
{
debugfs_remove_recursive(nbd->dbg_dir);
}
static int nbd_dbg_init(void)
{
struct dentry *dbg_dir;
dbg_dir = debugfs_create_dir("nbd", NULL);
if (!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(void *data, struct request *rq,
unsigned int hctx_idx, unsigned int request_idx,
unsigned int numa_node)
{
struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
cmd->nbd = data;
return 0;
}
static struct blk_mq_ops nbd_mq_ops = {
.queue_rq = nbd_queue_rq,
.init_request = nbd_init_request,
.timeout = nbd_xmit_timeout,
};
/*
* And here should be modules and kernel interface
* (Just smiley confuses emacs :-)
*/
static int __init nbd_init(void)
{
int err = -ENOMEM;
int i;
int part_shift;
BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
if (max_part < 0) {
printk(KERN_ERR "nbd: 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;
nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL);
if (!nbd_dev)
return -ENOMEM;
for (i = 0; i < nbds_max; i++) {
struct request_queue *q;
struct gendisk *disk = alloc_disk(1 << part_shift);
if (!disk)
goto out;
nbd_dev[i].disk = disk;
nbd_dev[i].tag_set.ops = &nbd_mq_ops;
nbd_dev[i].tag_set.nr_hw_queues = 1;
nbd_dev[i].tag_set.queue_depth = 128;
nbd_dev[i].tag_set.numa_node = NUMA_NO_NODE;
nbd_dev[i].tag_set.cmd_size = sizeof(struct nbd_cmd);
nbd_dev[i].tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
BLK_MQ_F_SG_MERGE | BLK_MQ_F_BLOCKING;
nbd_dev[i].tag_set.driver_data = &nbd_dev[i];
err = blk_mq_alloc_tag_set(&nbd_dev[i].tag_set);
if (err) {
put_disk(disk);
goto out;
}
/*
* The new linux 2.5 block layer implementation requires
* every gendisk to have its very own request_queue struct.
* These structs are big so we dynamically allocate them.
*/
q = blk_mq_init_queue(&nbd_dev[i].tag_set);
if (IS_ERR(q)) {
blk_mq_free_tag_set(&nbd_dev[i].tag_set);
put_disk(disk);
goto out;
}
disk->queue = q;
/*
* Tell the block layer that we are not a rotational device
*/
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue);
disk->queue->limits.discard_granularity = 512;
blk_queue_max_discard_sectors(disk->queue, UINT_MAX);
disk->queue->limits.discard_zeroes_data = 0;
blk_queue_max_hw_sectors(disk->queue, 65536);
disk->queue->limits.max_sectors = 256;
}
if (register_blkdev(NBD_MAJOR, "nbd")) {
err = -EIO;
goto out;
}
printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR);
nbd_dbg_init();
for (i = 0; i < nbds_max; i++) {
struct gendisk *disk = nbd_dev[i].disk;
nbd_dev[i].magic = NBD_MAGIC;
mutex_init(&nbd_dev[i].config_lock);
disk->major = NBD_MAJOR;
disk->first_minor = i << part_shift;
disk->fops = &nbd_fops;
disk->private_data = &nbd_dev[i];
sprintf(disk->disk_name, "nbd%d", i);
init_waitqueue_head(&nbd_dev[i].recv_wq);
nbd_reset(&nbd_dev[i]);
add_disk(disk);
}
return 0;
out:
while (i--) {
blk_mq_free_tag_set(&nbd_dev[i].tag_set);
blk_cleanup_queue(nbd_dev[i].disk->queue);
put_disk(nbd_dev[i].disk);
}
kfree(nbd_dev);
return err;
}
static void __exit nbd_cleanup(void)
{
int i;
nbd_dbg_close();
for (i = 0; i < nbds_max; i++) {
struct gendisk *disk = nbd_dev[i].disk;
nbd_dev[i].magic = 0;
if (disk) {
del_gendisk(disk);
blk_cleanup_queue(disk->queue);
blk_mq_free_tag_set(&nbd_dev[i].tag_set);
put_disk(disk);
}
}
unregister_blkdev(NBD_MAJOR, "nbd");
kfree(nbd_dev);
printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);
}
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: 0)");