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DEFINITIONS
This source file includes following definitions.
- fuse_get_conn
- fuse_request_init
- fuse_request_alloc
- fuse_request_alloc_nofs
- fuse_request_free
- block_sigs
- restore_sigs
- __fuse_get_request
- __fuse_put_request
- fuse_req_init_context
- fuse_get_req
- get_reserved_req
- put_reserved_req
- fuse_get_req_nofail
- fuse_put_request
- len_args
- fuse_get_unique
- queue_request
- flush_bg_queue
- request_end
- wait_answer_interruptible
- queue_interrupt
- request_wait_answer
- request_send
- request_send_nowait_locked
- request_send_nowait
- request_send_noreply
- request_send_background
- request_send_background_locked
- lock_request
- unlock_request
- fuse_copy_init
- fuse_copy_finish
- fuse_copy_fill
- fuse_copy_do
- fuse_copy_page
- fuse_copy_pages
- fuse_copy_one
- fuse_copy_args
- request_pending
- request_wait
- fuse_read_interrupt
- fuse_dev_read
- request_find
- copy_out_args
- fuse_dev_write
- fuse_dev_poll
- end_requests
- end_io_requests
- fuse_abort_conn
- fuse_dev_release
- fuse_dev_fasync
- fuse_dev_init
- fuse_dev_cleanup
/*
FUSE: Filesystem in Userspace
Copyright (C) 2001-2006 Miklos Szeredi <miklos@szeredi.hu>
This program can be distributed under the terms of the GNU GPL.
See the file COPYING.
*/
#include "fuse_i.h"
#include <linux/init.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/uio.h>
#include <linux/miscdevice.h>
#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/slab.h>
MODULE_ALIAS_MISCDEV(FUSE_MINOR);
static struct kmem_cache *fuse_req_cachep;
static struct fuse_conn *fuse_get_conn(struct file *file)
{
/*
* Lockless access is OK, because file->private data is set
* once during mount and is valid until the file is released.
*/
return file->private_data;
}
static void fuse_request_init(struct fuse_req *req)
{
memset(req, 0, sizeof(*req));
INIT_LIST_HEAD(&req->list);
INIT_LIST_HEAD(&req->intr_entry);
init_waitqueue_head(&req->waitq);
atomic_set(&req->count, 1);
}
struct fuse_req *fuse_request_alloc(void)
{
struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_KERNEL);
if (req)
fuse_request_init(req);
return req;
}
struct fuse_req *fuse_request_alloc_nofs(void)
{
struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_NOFS);
if (req)
fuse_request_init(req);
return req;
}
void fuse_request_free(struct fuse_req *req)
{
kmem_cache_free(fuse_req_cachep, req);
}
static void block_sigs(sigset_t *oldset)
{
sigset_t mask;
siginitsetinv(&mask, sigmask(SIGKILL));
sigprocmask(SIG_BLOCK, &mask, oldset);
}
static void restore_sigs(sigset_t *oldset)
{
sigprocmask(SIG_SETMASK, oldset, NULL);
}
static void __fuse_get_request(struct fuse_req *req)
{
atomic_inc(&req->count);
}
/* Must be called with > 1 refcount */
static void __fuse_put_request(struct fuse_req *req)
{
BUG_ON(atomic_read(&req->count) < 2);
atomic_dec(&req->count);
}
static void fuse_req_init_context(struct fuse_req *req)
{
req->in.h.uid = current->fsuid;
req->in.h.gid = current->fsgid;
req->in.h.pid = current->pid;
}
struct fuse_req *fuse_get_req(struct fuse_conn *fc)
{
struct fuse_req *req;
sigset_t oldset;
int intr;
int err;
atomic_inc(&fc->num_waiting);
block_sigs(&oldset);
intr = wait_event_interruptible(fc->blocked_waitq, !fc->blocked);
restore_sigs(&oldset);
err = -EINTR;
if (intr)
goto out;
err = -ENOTCONN;
if (!fc->connected)
goto out;
req = fuse_request_alloc();
err = -ENOMEM;
if (!req)
goto out;
fuse_req_init_context(req);
req->waiting = 1;
return req;
out:
atomic_dec(&fc->num_waiting);
return ERR_PTR(err);
}
/*
* Return request in fuse_file->reserved_req. However that may
* currently be in use. If that is the case, wait for it to become
* available.
*/
static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
struct file *file)
{
struct fuse_req *req = NULL;
struct fuse_file *ff = file->private_data;
do {
wait_event(fc->reserved_req_waitq, ff->reserved_req);
spin_lock(&fc->lock);
if (ff->reserved_req) {
req = ff->reserved_req;
ff->reserved_req = NULL;
get_file(file);
req->stolen_file = file;
}
spin_unlock(&fc->lock);
} while (!req);
return req;
}
/*
* Put stolen request back into fuse_file->reserved_req
*/
static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
{
struct file *file = req->stolen_file;
struct fuse_file *ff = file->private_data;
spin_lock(&fc->lock);
fuse_request_init(req);
BUG_ON(ff->reserved_req);
ff->reserved_req = req;
wake_up_all(&fc->reserved_req_waitq);
spin_unlock(&fc->lock);
fput(file);
}
/*
* Gets a requests for a file operation, always succeeds
*
* This is used for sending the FLUSH request, which must get to
* userspace, due to POSIX locks which may need to be unlocked.
*
* If allocation fails due to OOM, use the reserved request in
* fuse_file.
*
* This is very unlikely to deadlock accidentally, since the
* filesystem should not have it's own file open. If deadlock is
* intentional, it can still be broken by "aborting" the filesystem.
*/
struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file)
{
struct fuse_req *req;
atomic_inc(&fc->num_waiting);
wait_event(fc->blocked_waitq, !fc->blocked);
req = fuse_request_alloc();
if (!req)
req = get_reserved_req(fc, file);
fuse_req_init_context(req);
req->waiting = 1;
return req;
}
void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
{
if (atomic_dec_and_test(&req->count)) {
if (req->waiting)
atomic_dec(&fc->num_waiting);
if (req->stolen_file)
put_reserved_req(fc, req);
else
fuse_request_free(req);
}
}
static unsigned len_args(unsigned numargs, struct fuse_arg *args)
{
unsigned nbytes = 0;
unsigned i;
for (i = 0; i < numargs; i++)
nbytes += args[i].size;
return nbytes;
}
static u64 fuse_get_unique(struct fuse_conn *fc)
{
fc->reqctr++;
/* zero is special */
if (fc->reqctr == 0)
fc->reqctr = 1;
return fc->reqctr;
}
static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
{
req->in.h.unique = fuse_get_unique(fc);
req->in.h.len = sizeof(struct fuse_in_header) +
len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
list_add_tail(&req->list, &fc->pending);
req->state = FUSE_REQ_PENDING;
if (!req->waiting) {
req->waiting = 1;
atomic_inc(&fc->num_waiting);
}
wake_up(&fc->waitq);
kill_fasync(&fc->fasync, SIGIO, POLL_IN);
}
static void flush_bg_queue(struct fuse_conn *fc)
{
while (fc->active_background < FUSE_MAX_BACKGROUND &&
!list_empty(&fc->bg_queue)) {
struct fuse_req *req;
req = list_entry(fc->bg_queue.next, struct fuse_req, list);
list_del(&req->list);
fc->active_background++;
queue_request(fc, req);
}
}
/*
* This function is called when a request is finished. Either a reply
* has arrived or it was aborted (and not yet sent) or some error
* occurred during communication with userspace, or the device file
* was closed. The requester thread is woken up (if still waiting),
* the 'end' callback is called if given, else the reference to the
* request is released
*
* Called with fc->lock, unlocks it
*/
static void request_end(struct fuse_conn *fc, struct fuse_req *req)
__releases(fc->lock)
{
void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
req->end = NULL;
list_del(&req->list);
list_del(&req->intr_entry);
req->state = FUSE_REQ_FINISHED;
if (req->background) {
if (fc->num_background == FUSE_MAX_BACKGROUND) {
fc->blocked = 0;
wake_up_all(&fc->blocked_waitq);
}
if (fc->num_background == FUSE_CONGESTION_THRESHOLD) {
clear_bdi_congested(&fc->bdi, READ);
clear_bdi_congested(&fc->bdi, WRITE);
}
fc->num_background--;
fc->active_background--;
flush_bg_queue(fc);
}
spin_unlock(&fc->lock);
wake_up(&req->waitq);
if (end)
end(fc, req);
else
fuse_put_request(fc, req);
}
static void wait_answer_interruptible(struct fuse_conn *fc,
struct fuse_req *req)
__releases(fc->lock) __acquires(fc->lock)
{
if (signal_pending(current))
return;
spin_unlock(&fc->lock);
wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
spin_lock(&fc->lock);
}
static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req)
{
list_add_tail(&req->intr_entry, &fc->interrupts);
wake_up(&fc->waitq);
kill_fasync(&fc->fasync, SIGIO, POLL_IN);
}
static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
__releases(fc->lock) __acquires(fc->lock)
{
if (!fc->no_interrupt) {
/* Any signal may interrupt this */
wait_answer_interruptible(fc, req);
if (req->aborted)
goto aborted;
if (req->state == FUSE_REQ_FINISHED)
return;
req->interrupted = 1;
if (req->state == FUSE_REQ_SENT)
queue_interrupt(fc, req);
}
if (!req->force) {
sigset_t oldset;
/* Only fatal signals may interrupt this */
block_sigs(&oldset);
wait_answer_interruptible(fc, req);
restore_sigs(&oldset);
if (req->aborted)
goto aborted;
if (req->state == FUSE_REQ_FINISHED)
return;
/* Request is not yet in userspace, bail out */
if (req->state == FUSE_REQ_PENDING) {
list_del(&req->list);
__fuse_put_request(req);
req->out.h.error = -EINTR;
return;
}
}
/*
* Either request is already in userspace, or it was forced.
* Wait it out.
*/
spin_unlock(&fc->lock);
wait_event(req->waitq, req->state == FUSE_REQ_FINISHED);
spin_lock(&fc->lock);
if (!req->aborted)
return;
aborted:
BUG_ON(req->state != FUSE_REQ_FINISHED);
if (req->locked) {
/* This is uninterruptible sleep, because data is
being copied to/from the buffers of req. During
locked state, there mustn't be any filesystem
operation (e.g. page fault), since that could lead
to deadlock */
spin_unlock(&fc->lock);
wait_event(req->waitq, !req->locked);
spin_lock(&fc->lock);
}
}
void request_send(struct fuse_conn *fc, struct fuse_req *req)
{
req->isreply = 1;
spin_lock(&fc->lock);
if (!fc->connected)
req->out.h.error = -ENOTCONN;
else if (fc->conn_error)
req->out.h.error = -ECONNREFUSED;
else {
queue_request(fc, req);
/* acquire extra reference, since request is still needed
after request_end() */
__fuse_get_request(req);
request_wait_answer(fc, req);
}
spin_unlock(&fc->lock);
}
static void request_send_nowait_locked(struct fuse_conn *fc,
struct fuse_req *req)
{
req->background = 1;
fc->num_background++;
if (fc->num_background == FUSE_MAX_BACKGROUND)
fc->blocked = 1;
if (fc->num_background == FUSE_CONGESTION_THRESHOLD) {
set_bdi_congested(&fc->bdi, READ);
set_bdi_congested(&fc->bdi, WRITE);
}
list_add_tail(&req->list, &fc->bg_queue);
flush_bg_queue(fc);
}
static void request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
{
spin_lock(&fc->lock);
if (fc->connected) {
request_send_nowait_locked(fc, req);
spin_unlock(&fc->lock);
} else {
req->out.h.error = -ENOTCONN;
request_end(fc, req);
}
}
void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req)
{
req->isreply = 0;
request_send_nowait(fc, req);
}
void request_send_background(struct fuse_conn *fc, struct fuse_req *req)
{
req->isreply = 1;
request_send_nowait(fc, req);
}
/*
* Called under fc->lock
*
* fc->connected must have been checked previously
*/
void request_send_background_locked(struct fuse_conn *fc, struct fuse_req *req)
{
req->isreply = 1;
request_send_nowait_locked(fc, req);
}
/*
* Lock the request. Up to the next unlock_request() there mustn't be
* anything that could cause a page-fault. If the request was already
* aborted bail out.
*/
static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
{
int err = 0;
if (req) {
spin_lock(&fc->lock);
if (req->aborted)
err = -ENOENT;
else
req->locked = 1;
spin_unlock(&fc->lock);
}
return err;
}
/*
* Unlock request. If it was aborted during being locked, the
* requester thread is currently waiting for it to be unlocked, so
* wake it up.
*/
static void unlock_request(struct fuse_conn *fc, struct fuse_req *req)
{
if (req) {
spin_lock(&fc->lock);
req->locked = 0;
if (req->aborted)
wake_up(&req->waitq);
spin_unlock(&fc->lock);
}
}
struct fuse_copy_state {
struct fuse_conn *fc;
int write;
struct fuse_req *req;
const struct iovec *iov;
unsigned long nr_segs;
unsigned long seglen;
unsigned long addr;
struct page *pg;
void *mapaddr;
void *buf;
unsigned len;
};
static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc,
int write, struct fuse_req *req,
const struct iovec *iov, unsigned long nr_segs)
{
memset(cs, 0, sizeof(*cs));
cs->fc = fc;
cs->write = write;
cs->req = req;
cs->iov = iov;
cs->nr_segs = nr_segs;
}
/* Unmap and put previous page of userspace buffer */
static void fuse_copy_finish(struct fuse_copy_state *cs)
{
if (cs->mapaddr) {
kunmap_atomic(cs->mapaddr, KM_USER0);
if (cs->write) {
flush_dcache_page(cs->pg);
set_page_dirty_lock(cs->pg);
}
put_page(cs->pg);
cs->mapaddr = NULL;
}
}
/*
* Get another pagefull of userspace buffer, and map it to kernel
* address space, and lock request
*/
static int fuse_copy_fill(struct fuse_copy_state *cs)
{
unsigned long offset;
int err;
unlock_request(cs->fc, cs->req);
fuse_copy_finish(cs);
if (!cs->seglen) {
BUG_ON(!cs->nr_segs);
cs->seglen = cs->iov[0].iov_len;
cs->addr = (unsigned long) cs->iov[0].iov_base;
cs->iov ++;
cs->nr_segs --;
}
down_read(¤t->mm->mmap_sem);
err = get_user_pages(current, current->mm, cs->addr, 1, cs->write, 0,
&cs->pg, NULL);
up_read(¤t->mm->mmap_sem);
if (err < 0)
return err;
BUG_ON(err != 1);
offset = cs->addr % PAGE_SIZE;
cs->mapaddr = kmap_atomic(cs->pg, KM_USER0);
cs->buf = cs->mapaddr + offset;
cs->len = min(PAGE_SIZE - offset, cs->seglen);
cs->seglen -= cs->len;
cs->addr += cs->len;
return lock_request(cs->fc, cs->req);
}
/* Do as much copy to/from userspace buffer as we can */
static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
{
unsigned ncpy = min(*size, cs->len);
if (val) {
if (cs->write)
memcpy(cs->buf, *val, ncpy);
else
memcpy(*val, cs->buf, ncpy);
*val += ncpy;
}
*size -= ncpy;
cs->len -= ncpy;
cs->buf += ncpy;
return ncpy;
}
/*
* Copy a page in the request to/from the userspace buffer. Must be
* done atomically
*/
static int fuse_copy_page(struct fuse_copy_state *cs, struct page *page,
unsigned offset, unsigned count, int zeroing)
{
if (page && zeroing && count < PAGE_SIZE) {
void *mapaddr = kmap_atomic(page, KM_USER1);
memset(mapaddr, 0, PAGE_SIZE);
kunmap_atomic(mapaddr, KM_USER1);
}
while (count) {
int err;
if (!cs->len && (err = fuse_copy_fill(cs)))
return err;
if (page) {
void *mapaddr = kmap_atomic(page, KM_USER1);
void *buf = mapaddr + offset;
offset += fuse_copy_do(cs, &buf, &count);
kunmap_atomic(mapaddr, KM_USER1);
} else
offset += fuse_copy_do(cs, NULL, &count);
}
if (page && !cs->write)
flush_dcache_page(page);
return 0;
}
/* Copy pages in the request to/from userspace buffer */
static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
int zeroing)
{
unsigned i;
struct fuse_req *req = cs->req;
unsigned offset = req->page_offset;
unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset);
for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
struct page *page = req->pages[i];
int err = fuse_copy_page(cs, page, offset, count, zeroing);
if (err)
return err;
nbytes -= count;
count = min(nbytes, (unsigned) PAGE_SIZE);
offset = 0;
}
return 0;
}
/* Copy a single argument in the request to/from userspace buffer */
static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
{
while (size) {
int err;
if (!cs->len && (err = fuse_copy_fill(cs)))
return err;
fuse_copy_do(cs, &val, &size);
}
return 0;
}
/* Copy request arguments to/from userspace buffer */
static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
unsigned argpages, struct fuse_arg *args,
int zeroing)
{
int err = 0;
unsigned i;
for (i = 0; !err && i < numargs; i++) {
struct fuse_arg *arg = &args[i];
if (i == numargs - 1 && argpages)
err = fuse_copy_pages(cs, arg->size, zeroing);
else
err = fuse_copy_one(cs, arg->value, arg->size);
}
return err;
}
static int request_pending(struct fuse_conn *fc)
{
return !list_empty(&fc->pending) || !list_empty(&fc->interrupts);
}
/* Wait until a request is available on the pending list */
static void request_wait(struct fuse_conn *fc)
{
DECLARE_WAITQUEUE(wait, current);
add_wait_queue_exclusive(&fc->waitq, &wait);
while (fc->connected && !request_pending(fc)) {
set_current_state(TASK_INTERRUPTIBLE);
if (signal_pending(current))
break;
spin_unlock(&fc->lock);
schedule();
spin_lock(&fc->lock);
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&fc->waitq, &wait);
}
/*
* Transfer an interrupt request to userspace
*
* Unlike other requests this is assembled on demand, without a need
* to allocate a separate fuse_req structure.
*
* Called with fc->lock held, releases it
*/
static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_req *req,
const struct iovec *iov, unsigned long nr_segs)
__releases(fc->lock)
{
struct fuse_copy_state cs;
struct fuse_in_header ih;
struct fuse_interrupt_in arg;
unsigned reqsize = sizeof(ih) + sizeof(arg);
int err;
list_del_init(&req->intr_entry);
req->intr_unique = fuse_get_unique(fc);
memset(&ih, 0, sizeof(ih));
memset(&arg, 0, sizeof(arg));
ih.len = reqsize;
ih.opcode = FUSE_INTERRUPT;
ih.unique = req->intr_unique;
arg.unique = req->in.h.unique;
spin_unlock(&fc->lock);
if (iov_length(iov, nr_segs) < reqsize)
return -EINVAL;
fuse_copy_init(&cs, fc, 1, NULL, iov, nr_segs);
err = fuse_copy_one(&cs, &ih, sizeof(ih));
if (!err)
err = fuse_copy_one(&cs, &arg, sizeof(arg));
fuse_copy_finish(&cs);
return err ? err : reqsize;
}
/*
* Read a single request into the userspace filesystem's buffer. This
* function waits until a request is available, then removes it from
* the pending list and copies request data to userspace buffer. If
* no reply is needed (FORGET) or request has been aborted or there
* was an error during the copying then it's finished by calling
* request_end(). Otherwise add it to the processing list, and set
* the 'sent' flag.
*/
static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
int err;
struct fuse_req *req;
struct fuse_in *in;
struct fuse_copy_state cs;
unsigned reqsize;
struct file *file = iocb->ki_filp;
struct fuse_conn *fc = fuse_get_conn(file);
if (!fc)
return -EPERM;
restart:
spin_lock(&fc->lock);
err = -EAGAIN;
if ((file->f_flags & O_NONBLOCK) && fc->connected &&
!request_pending(fc))
goto err_unlock;
request_wait(fc);
err = -ENODEV;
if (!fc->connected)
goto err_unlock;
err = -ERESTARTSYS;
if (!request_pending(fc))
goto err_unlock;
if (!list_empty(&fc->interrupts)) {
req = list_entry(fc->interrupts.next, struct fuse_req,
intr_entry);
return fuse_read_interrupt(fc, req, iov, nr_segs);
}
req = list_entry(fc->pending.next, struct fuse_req, list);
req->state = FUSE_REQ_READING;
list_move(&req->list, &fc->io);
in = &req->in;
reqsize = in->h.len;
/* If request is too large, reply with an error and restart the read */
if (iov_length(iov, nr_segs) < reqsize) {
req->out.h.error = -EIO;
/* SETXATTR is special, since it may contain too large data */
if (in->h.opcode == FUSE_SETXATTR)
req->out.h.error = -E2BIG;
request_end(fc, req);
goto restart;
}
spin_unlock(&fc->lock);
fuse_copy_init(&cs, fc, 1, req, iov, nr_segs);
err = fuse_copy_one(&cs, &in->h, sizeof(in->h));
if (!err)
err = fuse_copy_args(&cs, in->numargs, in->argpages,
(struct fuse_arg *) in->args, 0);
fuse_copy_finish(&cs);
spin_lock(&fc->lock);
req->locked = 0;
if (req->aborted) {
request_end(fc, req);
return -ENODEV;
}
if (err) {
req->out.h.error = -EIO;
request_end(fc, req);
return err;
}
if (!req->isreply)
request_end(fc, req);
else {
req->state = FUSE_REQ_SENT;
list_move_tail(&req->list, &fc->processing);
if (req->interrupted)
queue_interrupt(fc, req);
spin_unlock(&fc->lock);
}
return reqsize;
err_unlock:
spin_unlock(&fc->lock);
return err;
}
/* Look up request on processing list by unique ID */
static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
{
struct list_head *entry;
list_for_each(entry, &fc->processing) {
struct fuse_req *req;
req = list_entry(entry, struct fuse_req, list);
if (req->in.h.unique == unique || req->intr_unique == unique)
return req;
}
return NULL;
}
static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
unsigned nbytes)
{
unsigned reqsize = sizeof(struct fuse_out_header);
if (out->h.error)
return nbytes != reqsize ? -EINVAL : 0;
reqsize += len_args(out->numargs, out->args);
if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
return -EINVAL;
else if (reqsize > nbytes) {
struct fuse_arg *lastarg = &out->args[out->numargs-1];
unsigned diffsize = reqsize - nbytes;
if (diffsize > lastarg->size)
return -EINVAL;
lastarg->size -= diffsize;
}
return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
out->page_zeroing);
}
/*
* Write a single reply to a request. First the header is copied from
* the write buffer. The request is then searched on the processing
* list by the unique ID found in the header. If found, then remove
* it from the list and copy the rest of the buffer to the request.
* The request is finished by calling request_end()
*/
static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
int err;
unsigned nbytes = iov_length(iov, nr_segs);
struct fuse_req *req;
struct fuse_out_header oh;
struct fuse_copy_state cs;
struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
if (!fc)
return -EPERM;
fuse_copy_init(&cs, fc, 0, NULL, iov, nr_segs);
if (nbytes < sizeof(struct fuse_out_header))
return -EINVAL;
err = fuse_copy_one(&cs, &oh, sizeof(oh));
if (err)
goto err_finish;
err = -EINVAL;
if (!oh.unique || oh.error <= -1000 || oh.error > 0 ||
oh.len != nbytes)
goto err_finish;
spin_lock(&fc->lock);
err = -ENOENT;
if (!fc->connected)
goto err_unlock;
req = request_find(fc, oh.unique);
if (!req)
goto err_unlock;
if (req->aborted) {
spin_unlock(&fc->lock);
fuse_copy_finish(&cs);
spin_lock(&fc->lock);
request_end(fc, req);
return -ENOENT;
}
/* Is it an interrupt reply? */
if (req->intr_unique == oh.unique) {
err = -EINVAL;
if (nbytes != sizeof(struct fuse_out_header))
goto err_unlock;
if (oh.error == -ENOSYS)
fc->no_interrupt = 1;
else if (oh.error == -EAGAIN)
queue_interrupt(fc, req);
spin_unlock(&fc->lock);
fuse_copy_finish(&cs);
return nbytes;
}
req->state = FUSE_REQ_WRITING;
list_move(&req->list, &fc->io);
req->out.h = oh;
req->locked = 1;
cs.req = req;
spin_unlock(&fc->lock);
err = copy_out_args(&cs, &req->out, nbytes);
fuse_copy_finish(&cs);
spin_lock(&fc->lock);
req->locked = 0;
if (!err) {
if (req->aborted)
err = -ENOENT;
} else if (!req->aborted)
req->out.h.error = -EIO;
request_end(fc, req);
return err ? err : nbytes;
err_unlock:
spin_unlock(&fc->lock);
err_finish:
fuse_copy_finish(&cs);
return err;
}
static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
{
unsigned mask = POLLOUT | POLLWRNORM;
struct fuse_conn *fc = fuse_get_conn(file);
if (!fc)
return POLLERR;
poll_wait(file, &fc->waitq, wait);
spin_lock(&fc->lock);
if (!fc->connected)
mask = POLLERR;
else if (request_pending(fc))
mask |= POLLIN | POLLRDNORM;
spin_unlock(&fc->lock);
return mask;
}
/*
* Abort all requests on the given list (pending or processing)
*
* This function releases and reacquires fc->lock
*/
static void end_requests(struct fuse_conn *fc, struct list_head *head)
{
while (!list_empty(head)) {
struct fuse_req *req;
req = list_entry(head->next, struct fuse_req, list);
req->out.h.error = -ECONNABORTED;
request_end(fc, req);
spin_lock(&fc->lock);
}
}
/*
* Abort requests under I/O
*
* The requests are set to aborted and finished, and the request
* waiter is woken up. This will make request_wait_answer() wait
* until the request is unlocked and then return.
*
* If the request is asynchronous, then the end function needs to be
* called after waiting for the request to be unlocked (if it was
* locked).
*/
static void end_io_requests(struct fuse_conn *fc)
__releases(fc->lock) __acquires(fc->lock)
{
while (!list_empty(&fc->io)) {
struct fuse_req *req =
list_entry(fc->io.next, struct fuse_req, list);
void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
req->aborted = 1;
req->out.h.error = -ECONNABORTED;
req->state = FUSE_REQ_FINISHED;
list_del_init(&req->list);
wake_up(&req->waitq);
if (end) {
req->end = NULL;
/* The end function will consume this reference */
__fuse_get_request(req);
spin_unlock(&fc->lock);
wait_event(req->waitq, !req->locked);
end(fc, req);
spin_lock(&fc->lock);
}
}
}
/*
* Abort all requests.
*
* Emergency exit in case of a malicious or accidental deadlock, or
* just a hung filesystem.
*
* The same effect is usually achievable through killing the
* filesystem daemon and all users of the filesystem. The exception
* is the combination of an asynchronous request and the tricky
* deadlock (see Documentation/filesystems/fuse.txt).
*
* During the aborting, progression of requests from the pending and
* processing lists onto the io list, and progression of new requests
* onto the pending list is prevented by req->connected being false.
*
* Progression of requests under I/O to the processing list is
* prevented by the req->aborted flag being true for these requests.
* For this reason requests on the io list must be aborted first.
*/
void fuse_abort_conn(struct fuse_conn *fc)
{
spin_lock(&fc->lock);
if (fc->connected) {
fc->connected = 0;
fc->blocked = 0;
end_io_requests(fc);
end_requests(fc, &fc->pending);
end_requests(fc, &fc->processing);
wake_up_all(&fc->waitq);
wake_up_all(&fc->blocked_waitq);
kill_fasync(&fc->fasync, SIGIO, POLL_IN);
}
spin_unlock(&fc->lock);
}
static int fuse_dev_release(struct inode *inode, struct file *file)
{
struct fuse_conn *fc = fuse_get_conn(file);
if (fc) {
spin_lock(&fc->lock);
fc->connected = 0;
end_requests(fc, &fc->pending);
end_requests(fc, &fc->processing);
spin_unlock(&fc->lock);
fasync_helper(-1, file, 0, &fc->fasync);
fuse_conn_put(fc);
}
return 0;
}
static int fuse_dev_fasync(int fd, struct file *file, int on)
{
struct fuse_conn *fc = fuse_get_conn(file);
if (!fc)
return -EPERM;
/* No locking - fasync_helper does its own locking */
return fasync_helper(fd, file, on, &fc->fasync);
}
const struct file_operations fuse_dev_operations = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.read = do_sync_read,
.aio_read = fuse_dev_read,
.write = do_sync_write,
.aio_write = fuse_dev_write,
.poll = fuse_dev_poll,
.release = fuse_dev_release,
.fasync = fuse_dev_fasync,
};
static struct miscdevice fuse_miscdevice = {
.minor = FUSE_MINOR,
.name = "fuse",
.fops = &fuse_dev_operations,
};
int __init fuse_dev_init(void)
{
int err = -ENOMEM;
fuse_req_cachep = kmem_cache_create("fuse_request",
sizeof(struct fuse_req),
0, 0, NULL);
if (!fuse_req_cachep)
goto out;
err = misc_register(&fuse_miscdevice);
if (err)
goto out_cache_clean;
return 0;
out_cache_clean:
kmem_cache_destroy(fuse_req_cachep);
out:
return err;
}
void fuse_dev_cleanup(void)
{
misc_deregister(&fuse_miscdevice);
kmem_cache_destroy(fuse_req_cachep);
}