- 根目录:
- fs
- fuse
- dev.c
/*
FUSE: Filesystem in Userspace
Copyright (C) 2001-2008 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>
#include <linux/pipe_fs_i.h>
#include <linux/swap.h>
#include <linux/splice.h>
#include <linux/aio.h>
#include <linux/freezer.h>
MODULE_ALIAS_MISCDEV(FUSE_MINOR);
MODULE_ALIAS("devname:fuse");
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, struct page **pages,
struct fuse_page_desc *page_descs,
unsigned npages)
{
memset(req, 0, sizeof(*req));
memset(pages, 0, sizeof(*pages) * npages);
memset(page_descs, 0, sizeof(*page_descs) * npages);
INIT_LIST_HEAD(&req->list);
INIT_LIST_HEAD(&req->intr_entry);
init_waitqueue_head(&req->waitq);
atomic_set(&req->count, 1);
req->pages = pages;
req->page_descs = page_descs;
req->max_pages = npages;
}
static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
{
struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags);
if (req) {
struct page **pages;
struct fuse_page_desc *page_descs;
if (npages <= FUSE_REQ_INLINE_PAGES) {
pages = req->inline_pages;
page_descs = req->inline_page_descs;
} else {
pages = kmalloc(sizeof(struct page *) * npages, flags);
page_descs = kmalloc(sizeof(struct fuse_page_desc) *
npages, flags);
}
if (!pages || !page_descs) {
kfree(pages);
kfree(page_descs);
kmem_cache_free(fuse_req_cachep, req);
return NULL;
}
fuse_request_init(req, pages, page_descs, npages);
}
return req;
}
struct fuse_req *fuse_request_alloc(unsigned npages)
{
return __fuse_request_alloc(npages, GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(fuse_request_alloc);
struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
{
return __fuse_request_alloc(npages, GFP_NOFS);
}
void fuse_request_free(struct fuse_req *req)
{
if (req->pages != req->inline_pages) {
kfree(req->pages);
kfree(req->page_descs);
}
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);
}
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 = from_kuid_munged(&init_user_ns, current_fsuid());
req->in.h.gid = from_kgid_munged(&init_user_ns, current_fsgid());
req->in.h.pid = current->pid;
}
static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
{
return !fc->initialized || (for_background && fc->blocked);
}
static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
bool for_background)
{
struct fuse_req *req;
int err;
atomic_inc(&fc->num_waiting);
if (fuse_block_alloc(fc, for_background)) {
sigset_t oldset;
int intr;
block_sigs(&oldset);
intr = wait_event_interruptible_exclusive(fc->blocked_waitq,
!fuse_block_alloc(fc, for_background));
restore_sigs(&oldset);
err = -EINTR;
if (intr)
goto out;
}
err = -ENOTCONN;
if (!fc->connected)
goto out;
req = fuse_request_alloc(npages);
err = -ENOMEM;
if (!req) {
if (for_background)
wake_up(&fc->blocked_waitq);
goto out;
}
fuse_req_init_context(req);
req->waiting = 1;
req->background = for_background;
return req;
out:
atomic_dec(&fc->num_waiting);
return ERR_PTR(err);
}
struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
{
return __fuse_get_req(fc, npages, false);
}
EXPORT_SYMBOL_GPL(fuse_get_req);
struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
unsigned npages)
{
return __fuse_get_req(fc, npages, true);
}
EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
/*
* 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;
req->stolen_file = get_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, req->pages, req->page_descs, req->max_pages);
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_nopages(struct fuse_conn *fc,
struct file *file)
{
struct fuse_req *req;
atomic_inc(&fc->num_waiting);
wait_event(fc->blocked_waitq, fc->initialized);
req = fuse_request_alloc(0);
if (!req)
req = get_reserved_req(fc, file);
fuse_req_init_context(req);
req->waiting = 1;
req->background = 0;
return req;
}
void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
{
if (atomic_dec_and_test(&req->count)) {
if (unlikely(req->background)) {
/*
* We get here in the unlikely case that a background
* request was allocated but not sent
*/
spin_lock(&fc->lock);
if (!fc->blocked)
wake_up(&fc->blocked_waitq);
spin_unlock(&fc->lock);
}
if (req->waiting)
atomic_dec(&fc->num_waiting);
if (req->stolen_file)
put_reserved_req(fc, req);
else
fuse_request_free(req);
}
}
EXPORT_SYMBOL_GPL(fuse_put_request);
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.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);
}
void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
u64 nodeid, u64 nlookup)
{
forget->forget_one.nodeid = nodeid;
forget->forget_one.nlookup = nlookup;
spin_lock(&fc->lock);
if (fc->connected) {
fc->forget_list_tail->next = forget;
fc->forget_list_tail = forget;
wake_up(&fc->waitq);
kill_fasync(&fc->fasync, SIGIO, POLL_IN);
} else {
kfree(forget);
}
spin_unlock(&fc->lock);
}
static void flush_bg_queue(struct fuse_conn *fc)
{
while (fc->active_background < fc->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++;
req->in.h.unique = fuse_get_unique(fc);
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) {
req->background = 0;
if (fc->num_background == fc->max_background)
fc->blocked = 0;
/* Wake up next waiter, if any */
if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
wake_up(&fc->blocked_waitq);
if (fc->num_background == fc->congestion_threshold &&
fc->connected && fc->bdi_initialized) {
clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
}
fc->num_background--;
fc->active_background--;
flush_bg_queue(fc);
}
spin_unlock(&fc->lock);
wake_up(&req->waitq);
if (end)
end(fc, req);
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);
while (req->state != FUSE_REQ_FINISHED)
wait_event_freezable(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);
}
}
static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
{
BUG_ON(req->background);
spin_lock(&fc->lock);
if (!fc->connected)
req->out.h.error = -ENOTCONN;
else if (fc->conn_error)
req->out.h.error = -ECONNREFUSED;
else {
req->in.h.unique = fuse_get_unique(fc);
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);
}
void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
{
req->isreply = 1;
__fuse_request_send(fc, req);
}
EXPORT_SYMBOL_GPL(fuse_request_send);
static void fuse_request_send_nowait_locked(struct fuse_conn *fc,
struct fuse_req *req)
{
BUG_ON(!req->background);
fc->num_background++;
if (fc->num_background == fc->max_background)
fc->blocked = 1;
if (fc->num_background == fc->congestion_threshold &&
fc->bdi_initialized) {
set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
}
list_add_tail(&req->list, &fc->bg_queue);
flush_bg_queue(fc);
}
static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
{
spin_lock(&fc->lock);
if (fc->connected) {
fuse_request_send_nowait_locked(fc, req);
spin_unlock(&fc->lock);
} else {
req->out.h.error = -ENOTCONN;
request_end(fc, req);
}
}
void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
{
req->isreply = 1;
fuse_request_send_nowait(fc, req);
}
EXPORT_SYMBOL_GPL(fuse_request_send_background);
static int fuse_request_send_notify_reply(struct fuse_conn *fc,
struct fuse_req *req, u64 unique)
{
int err = -ENODEV;
req->isreply = 0;
req->in.h.unique = unique;
spin_lock(&fc->lock);
if (fc->connected) {
queue_request(fc, req);
err = 0;
}
spin_unlock(&fc->lock);
return err;
}
/*
* Called under fc->lock
*
* fc->connected must have been checked previously
*/
void fuse_request_send_background_locked(struct fuse_conn *fc,
struct fuse_req *req)
{
req->isreply = 1;
fuse_request_send_nowait_locked(fc, req);
}
void fuse_force_forget(struct file *file, u64 nodeid)
{
struct inode *inode = file_inode(file);
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_req *req;
struct fuse_forget_in inarg;
memset(&inarg, 0, sizeof(inarg));
inarg.nlookup = 1;
req = fuse_get_req_nofail_nopages(fc, file);
req->in.h.opcode = FUSE_FORGET;
req->in.h.nodeid = nodeid;
req->in.numargs = 1;
req->in.args[0].size = sizeof(inarg);
req->in.args[0].value = &inarg;
req->isreply = 0;
__fuse_request_send(fc, req);
/* ignore errors */
fuse_put_request(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;
struct pipe_buffer *pipebufs;
struct pipe_buffer *currbuf;
struct pipe_inode_info *pipe;
unsigned long nr_segs;
unsigned long seglen;
unsigned long addr;
struct page *pg;
void *mapaddr;
void *buf;
unsigned len;
unsigned move_pages:1;
};
static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc,
int write,
const struct iovec *iov, unsigned long nr_segs)
{
memset(cs, 0, sizeof(*cs));
cs->fc = fc;
cs->write = write;
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->currbuf) {
struct pipe_buffer *buf = cs->currbuf;
if (!cs->write) {
buf->ops->unmap(cs->pipe, buf, cs->mapaddr);
} else {
kunmap(buf->page);
buf->len = PAGE_SIZE - cs->len;
}
cs->currbuf = NULL;
cs->mapaddr = NULL;
} else if (cs->mapaddr) {
kunmap(cs->pg);
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->pipebufs) {
struct pipe_buffer *buf = cs->pipebufs;
if (!cs->write) {
err = buf->ops->confirm(cs->pipe, buf);
if (err)
return err;
BUG_ON(!cs->nr_segs);
cs->currbuf = buf;
cs->mapaddr = buf->ops->map(cs->pipe, buf, 0);
cs->len = buf->len;
cs->buf = cs->mapaddr + buf->offset;
cs->pipebufs++;
cs->nr_segs--;
} else {
struct page *page;
if (cs->nr_segs == cs->pipe->buffers)
return -EIO;
page = alloc_page(GFP_HIGHUSER);
if (!page)
return -ENOMEM;
buf->page = page;
buf->offset = 0;
buf->len = 0;
cs->currbuf = buf;
cs->mapaddr = kmap(page);
cs->buf = cs->mapaddr;
cs->len = PAGE_SIZE;
cs->pipebufs++;
cs->nr_segs++;
}
} else {
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--;
}
err = get_user_pages_fast(cs->addr, 1, cs->write, &cs->pg);
if (err < 0)
return err;
BUG_ON(err != 1);
offset = cs->addr % PAGE_SIZE;
cs->mapaddr = kmap(cs->pg);
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;
}
static int fuse_check_page(struct page *page)
{
if (page_mapcount(page) ||
page->mapping != NULL ||
page_count(page) != 1 ||
(page->flags & PAGE_FLAGS_CHECK_AT_PREP &
~(1 << PG_locked |
1 << PG_referenced |
1 << PG_uptodate |
1 << PG_lru |
1 << PG_active |
1 << PG_reclaim))) {
printk(KERN_WARNING "fuse: trying to steal weird page\n");
printk(KERN_WARNING " page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);
return 1;
}
return 0;
}
static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
{
int err;
struct page *oldpage = *pagep;
struct page *newpage;
struct pipe_buffer *buf = cs->pipebufs;
unlock_request(cs->fc, cs->req);
fuse_copy_finish(cs);
err = buf->ops->confirm(cs->pipe, buf);
if (err)
return err;
BUG_ON(!cs->nr_segs);
cs->currbuf = buf;
cs->len = buf->len;
cs->pipebufs++;
cs->nr_segs--;
if (cs->len != PAGE_SIZE)
goto out_fallback;
if (buf->ops->steal(cs->pipe, buf) != 0)
goto out_fallback;
newpage = buf->page;
if (WARN_ON(!PageUptodate(newpage)))
return -EIO;
ClearPageMappedToDisk(newpage);
if (fuse_check_page(newpage) != 0)
goto out_fallback_unlock;
/*
* This is a new and locked page, it shouldn't be mapped or
* have any special flags on it
*/
if (WARN_ON(page_mapped(oldpage)))
goto out_fallback_unlock;
if (WARN_ON(page_has_private(oldpage)))
goto out_fallback_unlock;
if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
goto out_fallback_unlock;
if (WARN_ON(PageMlocked(oldpage)))
goto out_fallback_unlock;
err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
if (err) {
unlock_page(newpage);
return err;
}
page_cache_get(newpage);
if (!(buf->flags & PIPE_BUF_FLAG_LRU))
lru_cache_add_file(newpage);
err = 0;
spin_lock(&cs->fc->lock);
if (cs->req->aborted)
err = -ENOENT;
else
*pagep = newpage;
spin_unlock(&cs->fc->lock);
if (err) {
unlock_page(newpage);
page_cache_release(newpage);
return err;
}
unlock_page(oldpage);
page_cache_release(oldpage);
cs->len = 0;
return 0;
out_fallback_unlock:
unlock_page(newpage);
out_fallback:
cs->mapaddr = buf->ops->map(cs->pipe, buf, 1);
cs->buf = cs->mapaddr + buf->offset;
err = lock_request(cs->fc, cs->req);
if (err)
return err;
return 1;
}
static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
unsigned offset, unsigned count)
{
struct pipe_buffer *buf;
if (cs->nr_segs == cs->pipe->buffers)
return -EIO;
unlock_request(cs->fc, cs->req);
fuse_copy_finish(cs);
buf = cs->pipebufs;
page_cache_get(page);
buf->page = page;
buf->offset = offset;
buf->len = count;
cs->pipebufs++;
cs->nr_segs++;
cs->len = 0;
return 0;
}
/*
* 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 **pagep,
unsigned offset, unsigned count, int zeroing)
{
int err;
struct page *page = *pagep;
if (page && zeroing && count < PAGE_SIZE)
clear_highpage(page);
while (count) {
if (cs->write && cs->pipebufs && page) {
return fuse_ref_page(cs, page, offset, count);
} else if (!cs->len) {
if (cs->move_pages && page &&
offset == 0 && count == PAGE_SIZE) {
err = fuse_try_move_page(cs, pagep);
if (err <= 0)
return err;
} else {
err = fuse_copy_fill(cs);
if (err)
return err;
}
}
if (page) {
void *mapaddr = kmap_atomic(page);
void *buf = mapaddr + offset;
offset += fuse_copy_do(cs, &buf, &count);
kunmap_atomic(mapaddr);
} 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;
for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
int err;
unsigned offset = req->page_descs[i].offset;
unsigned count = min(nbytes, req->page_descs[i].length);
err = fuse_copy_page(cs, &req->pages[i], offset, count,
zeroing);
if (err)
return err;
nbytes -= count;
}
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) {
if (!cs->len) {
int err = fuse_copy_fill(cs);
if (err)
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 forget_pending(struct fuse_conn *fc)
{
return fc->forget_list_head.next != NULL;
}
static int request_pending(struct fuse_conn *fc)
{
return !list_empty(&fc->pending) || !list_empty(&fc->interrupts) ||
forget_pending(fc);
}
/* Wait until a request is available on the pending list */
static void request_wait(struct fuse_conn *fc)
__releases(fc->lock)
__acquires(fc->lock)
{
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_copy_state *cs,
size_t nbytes, struct fuse_req *req)
__releases(fc->lock)
{
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 (nbytes < reqsize)
return -EINVAL;
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;
}
static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc,
unsigned max,
unsigned *countp)
{
struct fuse_forget_link *head = fc->forget_list_head.next;
struct fuse_forget_link **newhead = &head;
unsigned count;
for (count = 0; *newhead != NULL && count < max; count++)
newhead = &(*newhead)->next;
fc->forget_list_head.next = *newhead;
*newhead = NULL;
if (fc->forget_list_head.next == NULL)
fc->forget_list_tail = &fc->forget_list_head;
if (countp != NULL)
*countp = count;
return head;
}
static int fuse_read_single_forget(struct fuse_conn *fc,
struct fuse_copy_state *cs,
size_t nbytes)
__releases(fc->lock)
{
int err;
struct fuse_forget_link *forget = dequeue_forget(fc, 1, NULL);
struct fuse_forget_in arg = {
.nlookup = forget->forget_one.nlookup,
};
struct fuse_in_header ih = {
.opcode = FUSE_FORGET,
.nodeid = forget->forget_one.nodeid,
.unique = fuse_get_unique(fc),
.len = sizeof(ih) + sizeof(arg),
};
spin_unlock(&fc->lock);
kfree(forget);
if (nbytes < ih.len)
return -EINVAL;
err = fuse_copy_one(cs, &ih, sizeof(ih));
if (!err)
err = fuse_copy_one(cs, &arg, sizeof(arg));
fuse_copy_finish(cs);
if (err)
return err;
return ih.len;
}
static int fuse_read_batch_forget(struct fuse_conn *fc,
struct fuse_copy_state *cs, size_t nbytes)
__releases(fc->lock)
{
int err;
unsigned max_forgets;
unsigned count;
struct fuse_forget_link *head;
struct fuse_batch_forget_in arg = { .count = 0 };
struct fuse_in_header ih = {
.opcode = FUSE_BATCH_FORGET,
.unique = fuse_get_unique(fc),
.len = sizeof(ih) + sizeof(arg),
};
if (nbytes < ih.len) {
spin_unlock(&fc->lock);
return -EINVAL;
}
max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
head = dequeue_forget(fc, max_forgets, &count);
spin_unlock(&fc->lock);
arg.count = count;
ih.len += count * sizeof(struct fuse_forget_one);
err = fuse_copy_one(cs, &ih, sizeof(ih));
if (!err)
err = fuse_copy_one(cs, &arg, sizeof(arg));
while (head) {
struct fuse_forget_link *forget = head;
if (!err) {
err = fuse_copy_one(cs, &forget->forget_one,
sizeof(forget->forget_one));
}
head = forget->next;
kfree(forget);
}
fuse_copy_finish(cs);
if (err)
return err;
return ih.len;
}
static int fuse_read_forget(struct fuse_conn *fc, struct fuse_copy_state *cs,
size_t nbytes)
__releases(fc->lock)
{
if (fc->minor < 16 || fc->forget_list_head.next->next == NULL)
return fuse_read_single_forget(fc, cs, nbytes);
else
return fuse_read_batch_forget(fc, cs, nbytes);
}
/*
* 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_do_read(struct fuse_conn *fc, struct file *file,
struct fuse_copy_state *cs, size_t nbytes)
{
int err;
struct fuse_req *req;
struct fuse_in *in;
unsigned reqsize;
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, cs, nbytes, req);
}
if (forget_pending(fc)) {
if (list_empty(&fc->pending) || fc->forget_batch-- > 0)
return fuse_read_forget(fc, cs, nbytes);
if (fc->forget_batch <= -8)
fc->forget_batch = 16;
}
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 (nbytes < 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);
cs->req = req;
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;
}
static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct fuse_copy_state cs;
struct file *file = iocb->ki_filp;
struct fuse_conn *fc = fuse_get_conn(file);
if (!fc)
return -EPERM;
fuse_copy_init(&cs, fc, 1, iov, nr_segs);
return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs));
}
static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe,
size_t len, unsigned int flags)
{
int ret;
int page_nr = 0;
int do_wakeup = 0;
struct pipe_buffer *bufs;
struct fuse_copy_state cs;
struct fuse_conn *fc = fuse_get_conn(in);
if (!fc)
return -EPERM;
bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
if (!bufs)
return -ENOMEM;
fuse_copy_init(&cs, fc, 1, NULL, 0);
cs.pipebufs = bufs;
cs.pipe = pipe;
ret = fuse_dev_do_read(fc, in, &cs, len);
if (ret < 0)
goto out;
ret = 0;
pipe_lock(pipe);
if (!pipe->readers) {
send_sig(SIGPIPE, current, 0);
if (!ret)
ret = -EPIPE;
goto out_unlock;
}
if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
ret = -EIO;
goto out_unlock;
}
while (page_nr < cs.nr_segs) {
int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
struct pipe_buffer *buf = pipe->bufs + newbuf;
buf->page = bufs[page_nr].page;
buf->offset = bufs[page_nr].offset;
buf->len = bufs[page_nr].len;
/*
* Need to be careful about this. Having buf->ops in module
* code can Oops if the buffer persists after module unload.
*/
buf->ops = &nosteal_pipe_buf_ops;
pipe->nrbufs++;
page_nr++;
ret += buf->len;
if (pipe->files)
do_wakeup = 1;
}
out_unlock:
pipe_unlock(pipe);
if (do_wakeup) {
smp_mb();
if (waitqueue_active(&pipe->wait))
wake_up_interruptible(&pipe->wait);
kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
}
out:
for (; page_nr < cs.nr_segs; page_nr++)
page_cache_release(bufs[page_nr].page);
kfree(bufs);
return ret;
}
static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
struct fuse_copy_state *cs)
{
struct fuse_notify_poll_wakeup_out outarg;
int err = -EINVAL;
if (size != sizeof(outarg))
goto err;
err = fuse_copy_one(cs, &outarg, sizeof(outarg));
if (err)
goto err;
fuse_copy_finish(cs);
return fuse_notify_poll_wakeup(fc, &outarg);
err:
fuse_copy_finish(cs);
return err;
}
static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
struct fuse_copy_state *cs)
{
struct fuse_notify_inval_inode_out outarg;
int err = -EINVAL;
if (size != sizeof(outarg))
goto err;
err = fuse_copy_one(cs, &outarg, sizeof(outarg));
if (err)
goto err;
fuse_copy_finish(cs);
down_read(&fc->killsb);
err = -ENOENT;
if (fc->sb) {
err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
outarg.off, outarg.len);
}
up_read(&fc->killsb);
return err;
err:
fuse_copy_finish(cs);
return err;
}
static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
struct fuse_copy_state *cs)
{
struct fuse_notify_inval_entry_out outarg;
int err = -ENOMEM;
char *buf;
struct qstr name;
buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
if (!buf)
goto err;
err = -EINVAL;
if (size < sizeof(outarg))
goto err;
err = fuse_copy_one(cs, &outarg, sizeof(outarg));
if (err)
goto err;
err = -ENAMETOOLONG;
if (outarg.namelen > FUSE_NAME_MAX)
goto err;
err = -EINVAL;
if (size != sizeof(outarg) + outarg.namelen + 1)
goto err;
name.name = buf;
name.len = outarg.namelen;
err = fuse_copy_one(cs, buf, outarg.namelen + 1);
if (err)
goto err;
fuse_copy_finish(cs);
buf[outarg.namelen] = 0;
name.hash = full_name_hash(name.name, name.len);
down_read(&fc->killsb);
err = -ENOENT;
if (fc->sb)
err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
up_read(&fc->killsb);
kfree(buf);
return err;
err:
kfree(buf);
fuse_copy_finish(cs);
return err;
}
static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
struct fuse_copy_state *cs)
{
struct fuse_notify_delete_out outarg;
int err = -ENOMEM;
char *buf;
struct qstr name;
buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
if (!buf)
goto err;
err = -EINVAL;
if (size < sizeof(outarg))
goto err;
err = fuse_copy_one(cs, &outarg, sizeof(outarg));
if (err)
goto err;
err = -ENAMETOOLONG;
if (outarg.namelen > FUSE_NAME_MAX)
goto err;
err = -EINVAL;
if (size != sizeof(outarg) + outarg.namelen + 1)
goto err;
name.name = buf;
name.len = outarg.namelen;
err = fuse_copy_one(cs, buf, outarg.namelen + 1);
if (err)
goto err;
fuse_copy_finish(cs);
buf[outarg.namelen] = 0;
name.hash = full_name_hash(name.name, name.len);
down_read(&fc->killsb);
err = -ENOENT;
if (fc->sb)
err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
outarg.child, &name);
up_read(&fc->killsb);
kfree(buf);
return err;
err:
kfree(buf);
fuse_copy_finish(cs);
return err;
}
static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
struct fuse_copy_state *cs)
{
struct fuse_notify_store_out outarg;
struct inode *inode;
struct address_space *mapping;
u64 nodeid;
int err;
pgoff_t index;
unsigned int offset;
unsigned int num;
loff_t file_size;
loff_t end;
err = -EINVAL;
if (size < sizeof(outarg))
goto out_finish;
err = fuse_copy_one(cs, &outarg, sizeof(outarg));
if (err)
goto out_finish;
err = -EINVAL;
if (size - sizeof(outarg) != outarg.size)
goto out_finish;
nodeid = outarg.nodeid;
down_read(&fc->killsb);
err = -ENOENT;
if (!fc->sb)
goto out_up_killsb;
inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
if (!inode)
goto out_up_killsb;
mapping = inode->i_mapping;
index = outarg.offset >> PAGE_CACHE_SHIFT;
offset = outarg.offset & ~PAGE_CACHE_MASK;
file_size = i_size_read(inode);
end = outarg.offset + outarg.size;
if (end > file_size) {
file_size = end;
fuse_write_update_size(inode, file_size);
}
num = outarg.size;
while (num) {
struct page *page;
unsigned int this_num;
err = -ENOMEM;
page = find_or_create_page(mapping, index,
mapping_gfp_mask(mapping));
if (!page)
goto out_iput;
this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
err = fuse_copy_page(cs, &page, offset, this_num, 0);
if (!err && offset == 0 &&
(this_num == PAGE_CACHE_SIZE || file_size == end))
SetPageUptodate(page);
unlock_page(page);
page_cache_release(page);
if (err)
goto out_iput;
num -= this_num;
offset = 0;
index++;
}
err = 0;
out_iput:
iput(inode);
out_up_killsb:
up_read(&fc->killsb);
out_finish:
fuse_copy_finish(cs);
return err;
}
static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
{
release_pages(req->pages, req->num_pages, 0);
}
static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
struct fuse_notify_retrieve_out *outarg)
{
int err;
struct address_space *mapping = inode->i_mapping;
struct fuse_req *req;
pgoff_t index;
loff_t file_size;
unsigned int num;
unsigned int offset;
size_t total_len = 0;
int num_pages;
offset = outarg->offset & ~PAGE_CACHE_MASK;
file_size = i_size_read(inode);
num = outarg->size;
if (outarg->offset > file_size)
num = 0;
else if (outarg->offset + num > file_size)
num = file_size - outarg->offset;
num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
req = fuse_get_req(fc, num_pages);
if (IS_ERR(req))
return PTR_ERR(req);
req->in.h.opcode = FUSE_NOTIFY_REPLY;
req->in.h.nodeid = outarg->nodeid;
req->in.numargs = 2;
req->in.argpages = 1;
req->page_descs[0].offset = offset;
req->end = fuse_retrieve_end;
index = outarg->offset >> PAGE_CACHE_SHIFT;
while (num && req->num_pages < num_pages) {
struct page *page;
unsigned int this_num;
page = find_get_page(mapping, index);
if (!page)
break;
this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
req->pages[req->num_pages] = page;
req->page_descs[req->num_pages].length = this_num;
req->num_pages++;
offset = 0;
num -= this_num;
total_len += this_num;
index++;
}
req->misc.retrieve_in.offset = outarg->offset;
req->misc.retrieve_in.size = total_len;
req->in.args[0].size = sizeof(req->misc.retrieve_in);
req->in.args[0].value = &req->misc.retrieve_in;
req->in.args[1].size = total_len;
err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
if (err)
fuse_retrieve_end(fc, req);
return err;
}
static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
struct fuse_copy_state *cs)
{
struct fuse_notify_retrieve_out outarg;
struct inode *inode;
int err;
err = -EINVAL;
if (size != sizeof(outarg))
goto copy_finish;
err = fuse_copy_one(cs, &outarg, sizeof(outarg));
if (err)
goto copy_finish;
fuse_copy_finish(cs);
down_read(&fc->killsb);
err = -ENOENT;
if (fc->sb) {
u64 nodeid = outarg.nodeid;
inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
if (inode) {
err = fuse_retrieve(fc, inode, &outarg);
iput(inode);
}
}
up_read(&fc->killsb);
return err;
copy_finish:
fuse_copy_finish(cs);
return err;
}
static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
unsigned int size, struct fuse_copy_state *cs)
{
switch (code) {
case FUSE_NOTIFY_POLL:
return fuse_notify_poll(fc, size, cs);
case FUSE_NOTIFY_INVAL_INODE:
return fuse_notify_inval_inode(fc, size, cs);
case FUSE_NOTIFY_INVAL_ENTRY:
return fuse_notify_inval_entry(fc, size, cs);
case FUSE_NOTIFY_STORE:
return fuse_notify_store(fc, size, cs);
case FUSE_NOTIFY_RETRIEVE:
return fuse_notify_retrieve(fc, size, cs);
case FUSE_NOTIFY_DELETE:
return fuse_notify_delete(fc, size, cs);
default:
fuse_copy_finish(cs);
return -EINVAL;
}
}
/* Look up request on processing list by unique ID */
static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
{
struct fuse_req *req;
list_for_each_entry(req, &fc->processing, 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_do_write(struct fuse_conn *fc,
struct fuse_copy_state *cs, size_t nbytes)
{
int err;
struct fuse_req *req;
struct fuse_out_header oh;
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.len != nbytes)
goto err_finish;
/*
* Zero oh.unique indicates unsolicited notification message
* and error contains notification code.
*/
if (!oh.unique) {
err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
return err ? err : nbytes;
}
err = -EINVAL;
if (oh.error <= -1000 || oh.error > 0)
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;
if (!req->out.page_replace)
cs->move_pages = 0;
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 ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
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, iov, nr_segs);
return fuse_dev_do_write(fc, &cs, iov_length(iov, nr_segs));
}
static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
struct file *out, loff_t *ppos,
size_t len, unsigned int flags)
{
unsigned nbuf;
unsigned idx;
struct pipe_buffer *bufs;
struct fuse_copy_state cs;
struct fuse_conn *fc;
size_t rem;
ssize_t ret;
fc = fuse_get_conn(out);
if (!fc)
return -EPERM;
bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
if (!bufs)
return -ENOMEM;
pipe_lock(pipe);
nbuf = 0;
rem = 0;
for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
ret = -EINVAL;
if (rem < len) {
pipe_unlock(pipe);
goto out;
}
rem = len;
while (rem) {
struct pipe_buffer *ibuf;
struct pipe_buffer *obuf;
BUG_ON(nbuf >= pipe->buffers);
BUG_ON(!pipe->nrbufs);
ibuf = &pipe->bufs[pipe->curbuf];
obuf = &bufs[nbuf];
if (rem >= ibuf->len) {
*obuf = *ibuf;
ibuf->ops = NULL;
pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
pipe->nrbufs--;
} else {
ibuf->ops->get(pipe, ibuf);
*obuf = *ibuf;
obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
obuf->len = rem;
ibuf->offset += obuf->len;
ibuf->len -= obuf->len;
}
nbuf++;
rem -= obuf->len;
}
pipe_unlock(pipe);
fuse_copy_init(&cs, fc, 0, NULL, nbuf);
cs.pipebufs = bufs;
cs.pipe = pipe;
if (flags & SPLICE_F_MOVE)
cs.move_pages = 1;
ret = fuse_dev_do_write(fc, &cs, len);
for (idx = 0; idx < nbuf; idx++) {
struct pipe_buffer *buf = &bufs[idx];
buf->ops->release(pipe, buf);
}
out:
kfree(bufs);
return ret;
}
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)
__releases(fc->lock)
__acquires(fc->lock)
{
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;
__fuse_get_request(req);
spin_unlock(&fc->lock);
wait_event(req->waitq, !req->locked);
end(fc, req);
fuse_put_request(fc, req);
spin_lock(&fc->lock);
}
}
}
static void end_queued_requests(struct fuse_conn *fc)
__releases(fc->lock)
__acquires(fc->lock)
{
fc->max_background = UINT_MAX;
flush_bg_queue(fc);
end_requests(fc, &fc->pending);
end_requests(fc, &fc->processing);
while (forget_pending(fc))
kfree(dequeue_forget(fc, 1, NULL));
}
static void end_polls(struct fuse_conn *fc)
{
struct rb_node *p;
p = rb_first(&fc->polled_files);
while (p) {
struct fuse_file *ff;
ff = rb_entry(p, struct fuse_file, polled_node);
wake_up_interruptible_all(&ff->poll_wait);
p = rb_next(p);
}
}
/*
* 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;
fc->initialized = 1;
end_io_requests(fc);
end_queued_requests(fc);
end_polls(fc);
wake_up_all(&fc->waitq);
wake_up_all(&fc->blocked_waitq);
kill_fasync(&fc->fasync, SIGIO, POLL_IN);
}
spin_unlock(&fc->lock);
}
EXPORT_SYMBOL_GPL(fuse_abort_conn);
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;
fc->blocked = 0;
fc->initialized = 1;
end_queued_requests(fc);
end_polls(fc);
wake_up_all(&fc->blocked_waitq);
spin_unlock(&fc->lock);
fuse_conn_put(fc);
}
return 0;
}
EXPORT_SYMBOL_GPL(fuse_dev_release);
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,
.splice_read = fuse_dev_splice_read,
.write = do_sync_write,
.aio_write = fuse_dev_write,
.splice_write = fuse_dev_splice_write,
.poll = fuse_dev_poll,
.release = fuse_dev_release,
.fasync = fuse_dev_fasync,
};
EXPORT_SYMBOL_GPL(fuse_dev_operations);
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);
}