blob: d41cd3342d3ab9c74d599cf0d1bf2d2f069e268a [file] [log] [blame]
/*
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/sched/signal.h>
#include <linux/uio.h>
#include <linux/miscdevice.h>
#include <linux/namei.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/sched.h>
MODULE_ALIAS_MISCDEV(FUSE_MINOR);
MODULE_ALIAS("devname:fuse");
/* Ordinary requests have even IDs, while interrupts IDs are odd */
#define FUSE_INT_REQ_BIT (1ULL << 0)
#define FUSE_REQ_ID_STEP (1ULL << 1)
static struct kmem_cache *fuse_req_cachep;
static struct fuse_dev *fuse_get_dev(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 READ_ONCE(file->private_data);
}
static void fuse_request_init(struct fuse_req *req)
{
INIT_LIST_HEAD(&req->list);
INIT_LIST_HEAD(&req->intr_entry);
init_waitqueue_head(&req->waitq);
refcount_set(&req->count, 1);
__set_bit(FR_PENDING, &req->flags);
}
static struct fuse_req *fuse_request_alloc(gfp_t flags)
{
struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags);
if (req)
fuse_request_init(req);
return req;
}
static void fuse_request_free(struct fuse_req *req)
{
kmem_cache_free(fuse_req_cachep, req);
}
static void __fuse_get_request(struct fuse_req *req)
{
refcount_inc(&req->count);
}
/* Must be called with > 1 refcount */
static void __fuse_put_request(struct fuse_req *req)
{
refcount_dec(&req->count);
}
void fuse_set_initialized(struct fuse_conn *fc)
{
/* Make sure stores before this are seen on another CPU */
smp_wmb();
fc->initialized = 1;
}
static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
{
return !fc->initialized || (for_background && fc->blocked);
}
static void fuse_drop_waiting(struct fuse_conn *fc)
{
/*
* lockess check of fc->connected is okay, because atomic_dec_and_test()
* provides a memory barrier mached with the one in fuse_wait_aborted()
* to ensure no wake-up is missed.
*/
if (atomic_dec_and_test(&fc->num_waiting) &&
!READ_ONCE(fc->connected)) {
/* wake up aborters */
wake_up_all(&fc->blocked_waitq);
}
}
static void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
static struct fuse_req *fuse_get_req(struct fuse_conn *fc, bool for_background)
{
struct fuse_req *req;
int err;
atomic_inc(&fc->num_waiting);
if (fuse_block_alloc(fc, for_background)) {
err = -EINTR;
if (wait_event_killable_exclusive(fc->blocked_waitq,
!fuse_block_alloc(fc, for_background)))
goto out;
}
/* Matches smp_wmb() in fuse_set_initialized() */
smp_rmb();
err = -ENOTCONN;
if (!fc->connected)
goto out;
err = -ECONNREFUSED;
if (fc->conn_error)
goto out;
req = fuse_request_alloc(GFP_KERNEL);
err = -ENOMEM;
if (!req) {
if (for_background)
wake_up(&fc->blocked_waitq);
goto out;
}
req->in.h.uid = from_kuid(fc->user_ns, current_fsuid());
req->in.h.gid = from_kgid(fc->user_ns, current_fsgid());
req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
__set_bit(FR_WAITING, &req->flags);
if (for_background)
__set_bit(FR_BACKGROUND, &req->flags);
if (unlikely(req->in.h.uid == ((uid_t)-1) ||
req->in.h.gid == ((gid_t)-1))) {
fuse_put_request(fc, req);
return ERR_PTR(-EOVERFLOW);
}
return req;
out:
fuse_drop_waiting(fc);
return ERR_PTR(err);
}
static void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
{
if (refcount_dec_and_test(&req->count)) {
if (test_bit(FR_BACKGROUND, &req->flags)) {
/*
* We get here in the unlikely case that a background
* request was allocated but not sent
*/
spin_lock(&fc->bg_lock);
if (!fc->blocked)
wake_up(&fc->blocked_waitq);
spin_unlock(&fc->bg_lock);
}
if (test_bit(FR_WAITING, &req->flags)) {
__clear_bit(FR_WAITING, &req->flags);
fuse_drop_waiting(fc);
}
fuse_request_free(req);
}
}
unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args)
{
unsigned nbytes = 0;
unsigned i;
for (i = 0; i < numargs; i++)
nbytes += args[i].size;
return nbytes;
}
EXPORT_SYMBOL_GPL(fuse_len_args);
u64 fuse_get_unique(struct fuse_iqueue *fiq)
{
fiq->reqctr += FUSE_REQ_ID_STEP;
return fiq->reqctr;
}
EXPORT_SYMBOL_GPL(fuse_get_unique);
static unsigned int fuse_req_hash(u64 unique)
{
return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS);
}
/**
* A new request is available, wake fiq->waitq
*/
static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq)
__releases(fiq->lock)
{
wake_up(&fiq->waitq);
kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
spin_unlock(&fiq->lock);
}
const struct fuse_iqueue_ops fuse_dev_fiq_ops = {
.wake_forget_and_unlock = fuse_dev_wake_and_unlock,
.wake_interrupt_and_unlock = fuse_dev_wake_and_unlock,
.wake_pending_and_unlock = fuse_dev_wake_and_unlock,
};
EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops);
static void queue_request_and_unlock(struct fuse_iqueue *fiq,
struct fuse_req *req)
__releases(fiq->lock)
{
req->in.h.len = sizeof(struct fuse_in_header) +
fuse_len_args(req->args->in_numargs,
(struct fuse_arg *) req->args->in_args);
list_add_tail(&req->list, &fiq->pending);
fiq->ops->wake_pending_and_unlock(fiq);
}
void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
u64 nodeid, u64 nlookup)
{
struct fuse_iqueue *fiq = &fc->iq;
forget->forget_one.nodeid = nodeid;
forget->forget_one.nlookup = nlookup;
spin_lock(&fiq->lock);
if (fiq->connected) {
fiq->forget_list_tail->next = forget;
fiq->forget_list_tail = forget;
fiq->ops->wake_forget_and_unlock(fiq);
} else {
kfree(forget);
spin_unlock(&fiq->lock);
}
}
static void flush_bg_queue(struct fuse_conn *fc)
{
struct fuse_iqueue *fiq = &fc->iq;
while (fc->active_background < fc->max_background &&
!list_empty(&fc->bg_queue)) {
struct fuse_req *req;
req = list_first_entry(&fc->bg_queue, struct fuse_req, list);
list_del(&req->list);
fc->active_background++;
spin_lock(&fiq->lock);
req->in.h.unique = fuse_get_unique(fiq);
queue_request_and_unlock(fiq, 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
*/
void fuse_request_end(struct fuse_conn *fc, struct fuse_req *req)
{
struct fuse_iqueue *fiq = &fc->iq;
if (test_and_set_bit(FR_FINISHED, &req->flags))
goto put_request;
/*
* test_and_set_bit() implies smp_mb() between bit
* changing and below FR_INTERRUPTED check. Pairs with
* smp_mb() from queue_interrupt().
*/
if (test_bit(FR_INTERRUPTED, &req->flags)) {
spin_lock(&fiq->lock);
list_del_init(&req->intr_entry);
spin_unlock(&fiq->lock);
}
WARN_ON(test_bit(FR_PENDING, &req->flags));
WARN_ON(test_bit(FR_SENT, &req->flags));
if (test_bit(FR_BACKGROUND, &req->flags)) {
spin_lock(&fc->bg_lock);
clear_bit(FR_BACKGROUND, &req->flags);
if (fc->num_background == fc->max_background) {
fc->blocked = 0;
wake_up(&fc->blocked_waitq);
} else if (!fc->blocked) {
/*
* Wake up next waiter, if any. It's okay to use
* waitqueue_active(), as we've already synced up
* fc->blocked with waiters with the wake_up() call
* above.
*/
if (waitqueue_active(&fc->blocked_waitq))
wake_up(&fc->blocked_waitq);
}
if (fc->num_background == fc->congestion_threshold && fc->sb) {
clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
}
fc->num_background--;
fc->active_background--;
flush_bg_queue(fc);
spin_unlock(&fc->bg_lock);
} else {
/* Wake up waiter sleeping in request_wait_answer() */
wake_up(&req->waitq);
}
if (test_bit(FR_ASYNC, &req->flags))
req->args->end(fc, req->args, req->out.h.error);
put_request:
fuse_put_request(fc, req);
}
EXPORT_SYMBOL_GPL(fuse_request_end);
static int queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
{
spin_lock(&fiq->lock);
/* Check for we've sent request to interrupt this req */
if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) {
spin_unlock(&fiq->lock);
return -EINVAL;
}
if (list_empty(&req->intr_entry)) {
list_add_tail(&req->intr_entry, &fiq->interrupts);
/*
* Pairs with smp_mb() implied by test_and_set_bit()
* from request_end().
*/
smp_mb();
if (test_bit(FR_FINISHED, &req->flags)) {
list_del_init(&req->intr_entry);
spin_unlock(&fiq->lock);
return 0;
}
fiq->ops->wake_interrupt_and_unlock(fiq);
} else {
spin_unlock(&fiq->lock);
}
return 0;
}
static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
{
struct fuse_iqueue *fiq = &fc->iq;
int err;
if (!fc->no_interrupt) {
/* Any signal may interrupt this */
err = wait_event_interruptible(req->waitq,
test_bit(FR_FINISHED, &req->flags));
if (!err)
return;
set_bit(FR_INTERRUPTED, &req->flags);
/* matches barrier in fuse_dev_do_read() */
smp_mb__after_atomic();
if (test_bit(FR_SENT, &req->flags))
queue_interrupt(fiq, req);
}
if (!test_bit(FR_FORCE, &req->flags)) {
/* Only fatal signals may interrupt this */
err = wait_event_killable(req->waitq,
test_bit(FR_FINISHED, &req->flags));
if (!err)
return;
spin_lock(&fiq->lock);
/* Request is not yet in userspace, bail out */
if (test_bit(FR_PENDING, &req->flags)) {
list_del(&req->list);
spin_unlock(&fiq->lock);
__fuse_put_request(req);
req->out.h.error = -EINTR;
return;
}
spin_unlock(&fiq->lock);
}
/*
* Either request is already in userspace, or it was forced.
* Wait it out.
*/
wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
}
static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
{
struct fuse_iqueue *fiq = &fc->iq;
BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
spin_lock(&fiq->lock);
if (!fiq->connected) {
spin_unlock(&fiq->lock);
req->out.h.error = -ENOTCONN;
} else {
req->in.h.unique = fuse_get_unique(fiq);
/* acquire extra reference, since request is still needed
after fuse_request_end() */
__fuse_get_request(req);
queue_request_and_unlock(fiq, req);
request_wait_answer(fc, req);
/* Pairs with smp_wmb() in fuse_request_end() */
smp_rmb();
}
}
static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
{
if (fc->minor < 4 && args->opcode == FUSE_STATFS)
args->out_args[0].size = FUSE_COMPAT_STATFS_SIZE;
if (fc->minor < 9) {
switch (args->opcode) {
case FUSE_LOOKUP:
case FUSE_CREATE:
case FUSE_MKNOD:
case FUSE_MKDIR:
case FUSE_SYMLINK:
case FUSE_LINK:
args->out_args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
break;
case FUSE_GETATTR:
case FUSE_SETATTR:
args->out_args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
break;
}
}
if (fc->minor < 12) {
switch (args->opcode) {
case FUSE_CREATE:
args->in_args[0].size = sizeof(struct fuse_open_in);
break;
case FUSE_MKNOD:
args->in_args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
break;
}
}
}
static void fuse_force_creds(struct fuse_conn *fc, struct fuse_req *req)
{
req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
}
static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args)
{
req->in.h.opcode = args->opcode;
req->in.h.nodeid = args->nodeid;
req->args = args;
if (args->end)
__set_bit(FR_ASYNC, &req->flags);
}
ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
{
struct fuse_req *req;
ssize_t ret;
if (args->force) {
atomic_inc(&fc->num_waiting);
req = fuse_request_alloc(GFP_KERNEL | __GFP_NOFAIL);
if (!args->nocreds)
fuse_force_creds(fc, req);
__set_bit(FR_WAITING, &req->flags);
__set_bit(FR_FORCE, &req->flags);
} else {
WARN_ON(args->nocreds);
req = fuse_get_req(fc, false);
if (IS_ERR(req))
return PTR_ERR(req);
}
/* Needs to be done after fuse_get_req() so that fc->minor is valid */
fuse_adjust_compat(fc, args);
fuse_args_to_req(req, args);
if (!args->noreply)
__set_bit(FR_ISREPLY, &req->flags);
__fuse_request_send(fc, req);
ret = req->out.h.error;
if (!ret && args->out_argvar) {
BUG_ON(args->out_numargs == 0);
ret = args->out_args[args->out_numargs - 1].size;
}
fuse_put_request(fc, req);
return ret;
}
static bool fuse_request_queue_background(struct fuse_conn *fc,
struct fuse_req *req)
{
bool queued = false;
WARN_ON(!test_bit(FR_BACKGROUND, &req->flags));
if (!test_bit(FR_WAITING, &req->flags)) {
__set_bit(FR_WAITING, &req->flags);
atomic_inc(&fc->num_waiting);
}
__set_bit(FR_ISREPLY, &req->flags);
spin_lock(&fc->bg_lock);
if (likely(fc->connected)) {
fc->num_background++;
if (fc->num_background == fc->max_background)
fc->blocked = 1;
if (fc->num_background == fc->congestion_threshold && fc->sb) {
set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
}
list_add_tail(&req->list, &fc->bg_queue);
flush_bg_queue(fc);
queued = true;
}
spin_unlock(&fc->bg_lock);
return queued;
}
int fuse_simple_background(struct fuse_conn *fc, struct fuse_args *args,
gfp_t gfp_flags)
{
struct fuse_req *req;
if (args->force) {
WARN_ON(!args->nocreds);
req = fuse_request_alloc(gfp_flags);
if (!req)
return -ENOMEM;
__set_bit(FR_BACKGROUND, &req->flags);
} else {
WARN_ON(args->nocreds);
req = fuse_get_req(fc, true);
if (IS_ERR(req))
return PTR_ERR(req);
}
fuse_args_to_req(req, args);
if (!fuse_request_queue_background(fc, req)) {
fuse_put_request(fc, req);
return -ENOTCONN;
}
return 0;
}
EXPORT_SYMBOL_GPL(fuse_simple_background);
static int fuse_simple_notify_reply(struct fuse_conn *fc,
struct fuse_args *args, u64 unique)
{
struct fuse_req *req;
struct fuse_iqueue *fiq = &fc->iq;
int err = 0;
req = fuse_get_req(fc, false);
if (IS_ERR(req))
return PTR_ERR(req);
__clear_bit(FR_ISREPLY, &req->flags);
req->in.h.unique = unique;
fuse_args_to_req(req, args);
spin_lock(&fiq->lock);
if (fiq->connected) {
queue_request_and_unlock(fiq, req);
} else {
err = -ENODEV;
spin_unlock(&fiq->lock);
fuse_put_request(fc, req);
}
return err;
}
/*
* 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_req *req)
{
int err = 0;
if (req) {
spin_lock(&req->waitq.lock);
if (test_bit(FR_ABORTED, &req->flags))
err = -ENOENT;
else
set_bit(FR_LOCKED, &req->flags);
spin_unlock(&req->waitq.lock);
}
return err;
}
/*
* Unlock request. If it was aborted while locked, caller is responsible
* for unlocking and ending the request.
*/
static int unlock_request(struct fuse_req *req)
{
int err = 0;
if (req) {
spin_lock(&req->waitq.lock);
if (test_bit(FR_ABORTED, &req->flags))
err = -ENOENT;
else
clear_bit(FR_LOCKED, &req->flags);
spin_unlock(&req->waitq.lock);
}
return err;
}
struct fuse_copy_state {
int write;
struct fuse_req *req;
struct iov_iter *iter;
struct pipe_buffer *pipebufs;
struct pipe_buffer *currbuf;
struct pipe_inode_info *pipe;
unsigned long nr_segs;
struct page *pg;
unsigned len;
unsigned offset;
unsigned move_pages:1;
};
static void fuse_copy_init(struct fuse_copy_state *cs, int write,
struct iov_iter *iter)
{
memset(cs, 0, sizeof(*cs));
cs->write = write;
cs->iter = iter;
}
/* 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->len = PAGE_SIZE - cs->len;
cs->currbuf = NULL;
} else if (cs->pg) {
if (cs->write) {
flush_dcache_page(cs->pg);
set_page_dirty_lock(cs->pg);
}
put_page(cs->pg);
}
cs->pg = 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)
{
struct page *page;
int err;
err = unlock_request(cs->req);
if (err)
return err;
fuse_copy_finish(cs);
if (cs->pipebufs) {
struct pipe_buffer *buf = cs->pipebufs;
if (!cs->write) {
err = pipe_buf_confirm(cs->pipe, buf);
if (err)
return err;
BUG_ON(!cs->nr_segs);
cs->currbuf = buf;
cs->pg = buf->page;
cs->offset = buf->offset;
cs->len = buf->len;
cs->pipebufs++;
cs->nr_segs--;
} else {
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->pg = page;
cs->offset = 0;
cs->len = PAGE_SIZE;
cs->pipebufs++;
cs->nr_segs++;
}
} else {
size_t off;
err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
if (err < 0)
return err;
BUG_ON(!err);
cs->len = err;
cs->offset = off;
cs->pg = page;
iov_iter_advance(cs->iter, err);
}
return lock_request(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) {
void *pgaddr = kmap_atomic(cs->pg);
void *buf = pgaddr + cs->offset;
if (cs->write)
memcpy(buf, *val, ncpy);
else
memcpy(*val, buf, ncpy);
kunmap_atomic(pgaddr);
*val += ncpy;
}
*size -= ncpy;
cs->len -= ncpy;
cs->offset += ncpy;
return ncpy;
}
static int fuse_check_page(struct page *page)
{
if (page_mapcount(page) ||
page->mapping != NULL ||
(page->flags & PAGE_FLAGS_CHECK_AT_PREP &
~(1 << PG_locked |
1 << PG_referenced |
1 << PG_uptodate |
1 << PG_lru |
1 << PG_active |
1 << PG_workingset |
1 << PG_reclaim |
1 << PG_waiters))) {
pr_warn("trying to steal weird page\n");
pr_warn(" 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;
get_page(oldpage);
err = unlock_request(cs->req);
if (err)
goto out_put_old;
fuse_copy_finish(cs);
err = pipe_buf_confirm(cs->pipe, buf);
if (err)
goto out_put_old;
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 (pipe_buf_steal(cs->pipe, buf) != 0)
goto out_fallback;
newpage = buf->page;
if (!PageUptodate(newpage))
SetPageUptodate(newpage);
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);
goto out_put_old;
}
get_page(newpage);
if (!(buf->flags & PIPE_BUF_FLAG_LRU))
lru_cache_add_file(newpage);
/*
* Release while we have extra ref on stolen page. Otherwise
* anon_pipe_buf_release() might think the page can be reused.
*/
pipe_buf_release(cs->pipe, buf);
err = 0;
spin_lock(&cs->req->waitq.lock);
if (test_bit(FR_ABORTED, &cs->req->flags))
err = -ENOENT;
else
*pagep = newpage;
spin_unlock(&cs->req->waitq.lock);
if (err) {
unlock_page(newpage);
put_page(newpage);
goto out_put_old;
}
unlock_page(oldpage);
/* Drop ref for ap->pages[] array */
put_page(oldpage);
cs->len = 0;
err = 0;
out_put_old:
/* Drop ref obtained in this function */
put_page(oldpage);
return err;
out_fallback_unlock:
unlock_page(newpage);
out_fallback:
cs->pg = buf->page;
cs->offset = buf->offset;
err = lock_request(cs->req);
if (!err)
err = 1;
goto out_put_old;
}
static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
unsigned offset, unsigned count)
{
struct pipe_buffer *buf;
int err;
if (cs->nr_segs == cs->pipe->buffers)
return -EIO;
get_page(page);
err = unlock_request(cs->req);
if (err) {
put_page(page);
return err;
}
fuse_copy_finish(cs);
buf = cs->pipebufs;
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) {
/*
* Can't control lifetime of pipe buffers, so always
* copy user pages.
*/
if (cs->req->args->user_pages) {
err = fuse_copy_fill(cs);
if (err)
return err;
} else {
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;
struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args);
for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) {
int err;
unsigned int offset = ap->descs[i].offset;
unsigned int count = min(nbytes, ap->descs[i].length);
err = fuse_copy_page(cs, &ap->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_iqueue *fiq)
{
return fiq->forget_list_head.next != NULL;
}
static int request_pending(struct fuse_iqueue *fiq)
{
return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
forget_pending(fiq);
}
/*
* 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 fiq->lock held, releases it
*/
static int fuse_read_interrupt(struct fuse_iqueue *fiq,
struct fuse_copy_state *cs,
size_t nbytes, struct fuse_req *req)
__releases(fiq->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);
memset(&ih, 0, sizeof(ih));
memset(&arg, 0, sizeof(arg));
ih.len = reqsize;
ih.opcode = FUSE_INTERRUPT;
ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT);
arg.unique = req->in.h.unique;
spin_unlock(&fiq->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;
}
struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
unsigned int max,
unsigned int *countp)
{
struct fuse_forget_link *head = fiq->forget_list_head.next;
struct fuse_forget_link **newhead = &head;
unsigned count;
for (count = 0; *newhead != NULL && count < max; count++)
newhead = &(*newhead)->next;
fiq->forget_list_head.next = *newhead;
*newhead = NULL;
if (fiq->forget_list_head.next == NULL)
fiq->forget_list_tail = &fiq->forget_list_head;
if (countp != NULL)
*countp = count;
return head;
}
EXPORT_SYMBOL(fuse_dequeue_forget);
static int fuse_read_single_forget(struct fuse_iqueue *fiq,
struct fuse_copy_state *cs,
size_t nbytes)
__releases(fiq->lock)
{
int err;
struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 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(fiq),
.len = sizeof(ih) + sizeof(arg),
};
spin_unlock(&fiq->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_iqueue *fiq,
struct fuse_copy_state *cs, size_t nbytes)
__releases(fiq->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(fiq),
.len = sizeof(ih) + sizeof(arg),
};
if (nbytes < ih.len) {
spin_unlock(&fiq->lock);
return -EINVAL;
}
max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
head = fuse_dequeue_forget(fiq, max_forgets, &count);
spin_unlock(&fiq->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_iqueue *fiq,
struct fuse_copy_state *cs,
size_t nbytes)
__releases(fiq->lock)
{
if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
return fuse_read_single_forget(fiq, cs, nbytes);
else
return fuse_read_batch_forget(fiq, 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
* fuse_request_end(). Otherwise add it to the processing list, and set
* the 'sent' flag.
*/
static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
struct fuse_copy_state *cs, size_t nbytes)
{
ssize_t err;
struct fuse_conn *fc = fud->fc;
struct fuse_iqueue *fiq = &fc->iq;
struct fuse_pqueue *fpq = &fud->pq;
struct fuse_req *req;
struct fuse_args *args;
unsigned reqsize;
unsigned int hash;
/*
* Require sane minimum read buffer - that has capacity for fixed part
* of any request header + negotiated max_write room for data.
*
* Historically libfuse reserves 4K for fixed header room, but e.g.
* GlusterFS reserves only 80 bytes
*
* = `sizeof(fuse_in_header) + sizeof(fuse_write_in)`
*
* which is the absolute minimum any sane filesystem should be using
* for header room.
*/
if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER,
sizeof(struct fuse_in_header) +
sizeof(struct fuse_write_in) +
fc->max_write))
return -EINVAL;
restart:
for (;;) {
spin_lock(&fiq->lock);
if (!fiq->connected || request_pending(fiq))
break;
spin_unlock(&fiq->lock);
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
err = wait_event_interruptible_exclusive(fiq->waitq,
!fiq->connected || request_pending(fiq));
if (err)
return err;
}
if (!fiq->connected) {
err = fc->aborted ? -ECONNABORTED : -ENODEV;
goto err_unlock;
}
if (!list_empty(&fiq->interrupts)) {
req = list_entry(fiq->interrupts.next, struct fuse_req,
intr_entry);
return fuse_read_interrupt(fiq, cs, nbytes, req);
}
if (forget_pending(fiq)) {
if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
return fuse_read_forget(fc, fiq, cs, nbytes);
if (fiq->forget_batch <= -8)
fiq->forget_batch = 16;
}
req = list_entry(fiq->pending.next, struct fuse_req, list);
clear_bit(FR_PENDING, &req->flags);
list_del_init(&req->list);
spin_unlock(&fiq->lock);
args = req->args;
reqsize = req->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 (args->opcode == FUSE_SETXATTR)
req->out.h.error = -E2BIG;
fuse_request_end(fc, req);
goto restart;
}
spin_lock(&fpq->lock);
/*
* Must not put request on fpq->io queue after having been shut down by
* fuse_abort_conn()
*/
if (!fpq->connected) {
req->out.h.error = err = -ECONNABORTED;
goto out_end;
}
list_add(&req->list, &fpq->io);
spin_unlock(&fpq->lock);
cs->req = req;
err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h));
if (!err)
err = fuse_copy_args(cs, args->in_numargs, args->in_pages,
(struct fuse_arg *) args->in_args, 0);
fuse_copy_finish(cs);
spin_lock(&fpq->lock);
clear_bit(FR_LOCKED, &req->flags);
if (!fpq->connected) {
err = fc->aborted ? -ECONNABORTED : -ENODEV;
goto out_end;
}
if (err) {
req->out.h.error = -EIO;
goto out_end;
}
if (!test_bit(FR_ISREPLY, &req->flags)) {
err = reqsize;
goto out_end;
}
hash = fuse_req_hash(req->in.h.unique);
list_move_tail(&req->list, &fpq->processing[hash]);
__fuse_get_request(req);
set_bit(FR_SENT, &req->flags);
spin_unlock(&fpq->lock);
/* matches barrier in request_wait_answer() */
smp_mb__after_atomic();
if (test_bit(FR_INTERRUPTED, &req->flags))
queue_interrupt(fiq, req);
fuse_put_request(fc, req);
return reqsize;
out_end:
if (!test_bit(FR_PRIVATE, &req->flags))
list_del_init(&req->list);
spin_unlock(&fpq->lock);
fuse_request_end(fc, req);
return err;
err_unlock:
spin_unlock(&fiq->lock);
return err;
}
static int fuse_dev_open(struct inode *inode, struct file *file)
{
/*
* The fuse device's file's private_data is used to hold
* the fuse_conn(ection) when it is mounted, and is used to
* keep track of whether the file has been mounted already.
*/
file->private_data = NULL;
return 0;
}
static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
{
struct fuse_copy_state cs;
struct file *file = iocb->ki_filp;
struct fuse_dev *fud = fuse_get_dev(file);
if (!fud)
return -EPERM;
if (!iter_is_iovec(to))
return -EINVAL;
fuse_copy_init(&cs, 1, to);
return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
}
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 total, ret;
int page_nr = 0;
struct pipe_buffer *bufs;
struct fuse_copy_state cs;
struct fuse_dev *fud = fuse_get_dev(in);
if (!fud)
return -EPERM;
bufs = kvmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
GFP_KERNEL);
if (!bufs)
return -ENOMEM;
fuse_copy_init(&cs, 1, NULL);
cs.pipebufs = bufs;
cs.pipe = pipe;
ret = fuse_dev_do_read(fud, in, &cs, len);
if (ret < 0)
goto out;
if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
ret = -EIO;
goto out;
}
for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
/*
* Need to be careful about this. Having buf->ops in module
* code can Oops if the buffer persists after module unload.
*/
bufs[page_nr].ops = &nosteal_pipe_buf_ops;
bufs[page_nr].flags = 0;
ret = add_to_pipe(pipe, &bufs[page_nr++]);
if (unlikely(ret < 0))
break;
}
if (total)
ret = total;
out:
for (; page_nr < cs.nr_segs; page_nr++)
put_page(bufs[page_nr].page);
kvfree(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;
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;
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_SHIFT;
offset = outarg.offset & ~PAGE_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_SIZE - offset);
err = fuse_copy_page(cs, &page, offset, this_num, 0);
if (!err && offset == 0 &&
(this_num == PAGE_SIZE || file_size == end))
SetPageUptodate(page);
unlock_page(page);
put_page(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;
}
struct fuse_retrieve_args {
struct fuse_args_pages ap;
struct fuse_notify_retrieve_in inarg;
};
static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_args *args,
int error)
{
struct fuse_retrieve_args *ra =
container_of(args, typeof(*ra), ap.args);
release_pages(ra->ap.pages, ra->ap.num_pages);
kfree(ra);
}
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;
pgoff_t index;
loff_t file_size;
unsigned int num;
unsigned int offset;
size_t total_len = 0;
unsigned int num_pages;
struct fuse_retrieve_args *ra;
size_t args_size = sizeof(*ra);
struct fuse_args_pages *ap;
struct fuse_args *args;
offset = outarg->offset & ~PAGE_MASK;
file_size = i_size_read(inode);
num = min(outarg->size, fc->max_write);
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, fc->max_pages);
args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0]));
ra = kzalloc(args_size, GFP_KERNEL);
if (!ra)
return -ENOMEM;
ap = &ra->ap;
ap->pages = (void *) (ra + 1);
ap->descs = (void *) (ap->pages + num_pages);
args = &ap->args;
args->nodeid = outarg->nodeid;
args->opcode = FUSE_NOTIFY_REPLY;
args->in_numargs = 2;
args->in_pages = true;
args->end = fuse_retrieve_end;
index = outarg->offset >> PAGE_SHIFT;
while (num && ap->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_SIZE - offset);
ap->pages[ap->num_pages] = page;
ap->descs[ap->num_pages].offset = offset;
ap->descs[ap->num_pages].length = this_num;
ap->num_pages++;
offset = 0;
num -= this_num;
total_len += this_num;
index++;
}
ra->inarg.offset = outarg->offset;
ra->inarg.size = total_len;
args->in_args[0].size = sizeof(ra->inarg);
args->in_args[0].value = &ra->inarg;
args->in_args[1].size = total_len;
err = fuse_simple_notify_reply(fc, args, outarg->notify_unique);
if (err)
fuse_retrieve_end(fc, args, err);
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)
{
/* Don't try to move pages (yet) */
cs->move_pages = 0;
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_pqueue *fpq, u64 unique)
{
unsigned int hash = fuse_req_hash(unique);
struct fuse_req *req;
list_for_each_entry(req, &fpq->processing[hash], list) {
if (req->in.h.unique == unique)
return req;
}
return NULL;
}
static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
unsigned nbytes)
{
unsigned reqsize = sizeof(struct fuse_out_header);
reqsize += fuse_len_args(args->out_numargs, args->out_args);
if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar))
return -EINVAL;
else if (reqsize > nbytes) {
struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1];
unsigned diffsize = reqsize - nbytes;
if (diffsize > lastarg->size)
return -EINVAL;
lastarg->size -= diffsize;
}
return fuse_copy_args(cs, args->out_numargs, args->out_pages,
args->out_args, args->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 fuse_request_end().
*/
static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
struct fuse_copy_state *cs, size_t nbytes)
{
int err;
struct fuse_conn *fc = fud->fc;
struct fuse_pqueue *fpq = &fud->pq;
struct fuse_req *req;
struct fuse_out_header oh;
err = -EINVAL;
if (nbytes < sizeof(struct fuse_out_header))
goto out;
err = fuse_copy_one(cs, &oh, sizeof(oh));
if (err)
goto copy_finish;
err = -EINVAL;
if (oh.len != nbytes)
goto copy_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);
goto out;
}
err = -EINVAL;
if (oh.error <= -512 || oh.error > 0)
goto copy_finish;
spin_lock(&fpq->lock);
req = NULL;
if (fpq->connected)
req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT);
err = -ENOENT;
if (!req) {
spin_unlock(&fpq->lock);
goto copy_finish;
}
/* Is it an interrupt reply ID? */
if (oh.unique & FUSE_INT_REQ_BIT) {
__fuse_get_request(req);
spin_unlock(&fpq->lock);
err = 0;
if (nbytes != sizeof(struct fuse_out_header))
err = -EINVAL;
else if (oh.error == -ENOSYS)
fc->no_interrupt = 1;
else if (oh.error == -EAGAIN)
err = queue_interrupt(&fc->iq, req);
fuse_put_request(fc, req);
goto copy_finish;
}
clear_bit(FR_SENT, &req->flags);
list_move(&req->list, &fpq->io);
req->out.h = oh;
set_bit(FR_LOCKED, &req->flags);
spin_unlock(&fpq->lock);
cs->req = req;
if (!req->args->page_replace)
cs->move_pages = 0;
if (oh.error)
err = nbytes != sizeof(oh) ? -EINVAL : 0;
else
err = copy_out_args(cs, req->args, nbytes);
fuse_copy_finish(cs);
if (!err && req->in.h.opcode == FUSE_CANONICAL_PATH) {
char *path = (char *)req->args->out_args[0].value;
path[req->args->out_args[0].size - 1] = 0;
req->out.h.error =
kern_path(path, 0, req->args->canonical_path);
}
spin_lock(&fpq->lock);
clear_bit(FR_LOCKED, &req->flags);
if (!fpq->connected)
err = -ENOENT;
else if (err)
req->out.h.error = -EIO;
if (!test_bit(FR_PRIVATE, &req->flags))
list_del_init(&req->list);
spin_unlock(&fpq->lock);
fuse_request_end(fc, req);
out:
return err ? err : nbytes;
copy_finish:
fuse_copy_finish(cs);
goto out;
}
static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
{
struct fuse_copy_state cs;
struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
if (!fud)
return -EPERM;
if (!iter_is_iovec(from))
return -EINVAL;
fuse_copy_init(&cs, 0, from);
return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
}
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_dev *fud;
size_t rem;
ssize_t ret;
fud = fuse_get_dev(out);
if (!fud)
return -EPERM;
pipe_lock(pipe);
bufs = kvmalloc_array(pipe->nrbufs, sizeof(struct pipe_buffer),
GFP_KERNEL);
if (!bufs) {
pipe_unlock(pipe);
return -ENOMEM;
}
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)
goto out_free;
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 {
if (!pipe_buf_get(pipe, ibuf))
goto out_free;
*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, 0, NULL);
cs.pipebufs = bufs;
cs.nr_segs = nbuf;
cs.pipe = pipe;
if (flags & SPLICE_F_MOVE)
cs.move_pages = 1;
ret = fuse_dev_do_write(fud, &cs, len);
pipe_lock(pipe);
out_free:
for (idx = 0; idx < nbuf; idx++) {
struct pipe_buffer *buf = &bufs[idx];
if (buf->ops)
pipe_buf_release(pipe, buf);
}
pipe_unlock(pipe);
kvfree(bufs);
return ret;
}
static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
{
__poll_t mask = EPOLLOUT | EPOLLWRNORM;
struct fuse_iqueue *fiq;
struct fuse_dev *fud = fuse_get_dev(file);
if (!fud)
return EPOLLERR;
fiq = &fud->fc->iq;
poll_wait(file, &fiq->waitq, wait);
spin_lock(&fiq->lock);
if (!fiq->connected)
mask = EPOLLERR;
else if (request_pending(fiq))
mask |= EPOLLIN | EPOLLRDNORM;
spin_unlock(&fiq->lock);
return mask;
}
/* Abort all requests on the given list (pending or processing) */
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;
clear_bit(FR_SENT, &req->flags);
list_del_init(&req->list);
fuse_request_end(fc, req);
}
}
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).
*
* Aborting requests under I/O goes as follows: 1: Separate out unlocked
* requests, they should be finished off immediately. Locked requests will be
* finished after unlock; see unlock_request(). 2: Finish off the unlocked
* requests. It is possible that some request will finish before we can. This
* is OK, the request will in that case be removed from the list before we touch
* it.
*/
void fuse_abort_conn(struct fuse_conn *fc)
{
struct fuse_iqueue *fiq = &fc->iq;
spin_lock(&fc->lock);
if (fc->connected) {
struct fuse_dev *fud;
struct fuse_req *req, *next;
LIST_HEAD(to_end);
unsigned int i;
/* Background queuing checks fc->connected under bg_lock */
spin_lock(&fc->bg_lock);
fc->connected = 0;
spin_unlock(&fc->bg_lock);
fuse_set_initialized(fc);
list_for_each_entry(fud, &fc->devices, entry) {
struct fuse_pqueue *fpq = &fud->pq;
spin_lock(&fpq->lock);
fpq->connected = 0;
list_for_each_entry_safe(req, next, &fpq->io, list) {
req->out.h.error = -ECONNABORTED;
spin_lock(&req->waitq.lock);
set_bit(FR_ABORTED, &req->flags);
if (!test_bit(FR_LOCKED, &req->flags)) {
set_bit(FR_PRIVATE, &req->flags);
__fuse_get_request(req);
list_move(&req->list, &to_end);
}
spin_unlock(&req->waitq.lock);
}
for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
list_splice_tail_init(&fpq->processing[i],
&to_end);
spin_unlock(&fpq->lock);
}
spin_lock(&fc->bg_lock);
fc->blocked = 0;
fc->max_background = UINT_MAX;
flush_bg_queue(fc);
spin_unlock(&fc->bg_lock);
spin_lock(&fiq->lock);
fiq->connected = 0;
list_for_each_entry(req, &fiq->pending, list)
clear_bit(FR_PENDING, &req->flags);
list_splice_tail_init(&fiq->pending, &to_end);
while (forget_pending(fiq))
kfree(fuse_dequeue_forget(fiq, 1, NULL));
wake_up_all(&fiq->waitq);
spin_unlock(&fiq->lock);
kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
end_polls(fc);
wake_up_all(&fc->blocked_waitq);
spin_unlock(&fc->lock);
end_requests(fc, &to_end);
} else {
spin_unlock(&fc->lock);
}
}
EXPORT_SYMBOL_GPL(fuse_abort_conn);
void fuse_wait_aborted(struct fuse_conn *fc)
{
/* matches implicit memory barrier in fuse_drop_waiting() */
smp_mb();
wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
}
int fuse_dev_release(struct inode *inode, struct file *file)
{
struct fuse_dev *fud = fuse_get_dev(file);
if (fud) {
struct fuse_conn *fc = fud->fc;
struct fuse_pqueue *fpq = &fud->pq;
LIST_HEAD(to_end);
unsigned int i;
spin_lock(&fpq->lock);
WARN_ON(!list_empty(&fpq->io));
for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
list_splice_init(&fpq->processing[i], &to_end);
spin_unlock(&fpq->lock);
end_requests(fc, &to_end);
/* Are we the last open device? */
if (atomic_dec_and_test(&fc->dev_count)) {
WARN_ON(fc->iq.fasync != NULL);
fuse_abort_conn(fc);
}
fuse_dev_free(fud);
}
return 0;
}
EXPORT_SYMBOL_GPL(fuse_dev_release);
static int fuse_dev_fasync(int fd, struct file *file, int on)
{
struct fuse_dev *fud = fuse_get_dev(file);
if (!fud)
return -EPERM;
/* No locking - fasync_helper does its own locking */
return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
}
static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
{
struct fuse_dev *fud;
if (new->private_data)
return -EINVAL;
fud = fuse_dev_alloc_install(fc);
if (!fud)
return -ENOMEM;
new->private_data = fud;
atomic_inc(&fc->dev_count);
return 0;
}
static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int res;
int oldfd;
struct fuse_dev *fud = NULL;
switch (cmd) {
case FUSE_DEV_IOC_CLONE:
res = -EFAULT;
if (!get_user(oldfd, (__u32 __user *)arg)) {
struct file *old = fget(oldfd);
res = -EINVAL;
if (old) {
/*
* Check against file->f_op because CUSE
* uses the same ioctl handler.
*/
if (old->f_op == file->f_op &&
old->f_cred->user_ns ==
file->f_cred->user_ns)
fud = fuse_get_dev(old);
if (fud) {
mutex_lock(&fuse_mutex);
res = fuse_device_clone(fud->fc, file);
mutex_unlock(&fuse_mutex);
}
fput(old);
}
}
break;
case FUSE_DEV_IOC_PASSTHROUGH_OPEN:
res = -EFAULT;
if (!get_user(oldfd, (__u32 __user *)arg)) {
res = -EINVAL;
fud = fuse_get_dev(file);
if (fud)
res = fuse_passthrough_open(fud, oldfd);
}
break;
default:
res = -ENOTTY;
break;
}
return res;
}
const struct file_operations fuse_dev_operations = {
.owner = THIS_MODULE,
.open = fuse_dev_open,
.llseek = no_llseek,
.read_iter = fuse_dev_read,
.splice_read = fuse_dev_splice_read,
.write_iter = fuse_dev_write,
.splice_write = fuse_dev_splice_write,
.poll = fuse_dev_poll,
.release = fuse_dev_release,
.fasync = fuse_dev_fasync,
.unlocked_ioctl = fuse_dev_ioctl,
.compat_ioctl = fuse_dev_ioctl,
};
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);
}