linux/fs/fuse/dev.c
Alessio Balsini f8425c9396 fuse: 32-bit user space ioctl compat for fuse device
With a 64-bit kernel build the FUSE device cannot handle ioctl requests
coming from 32-bit user space.  This is due to the ioctl command
translation that generates different command identifiers that thus cannot
be used for direct comparisons without proper manipulation.

Explicitly extract type and number from the ioctl command to enable 32-bit
user space compatibility on 64-bit kernel builds.

Signed-off-by: Alessio Balsini <balsini@android.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-03-16 15:20:16 +01:00

2319 lines
52 KiB
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/sched/signal.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/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_mount *fm, 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);
req->fm = fm;
}
static struct fuse_req *fuse_request_alloc(struct fuse_mount *fm, gfp_t flags)
{
struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags);
if (req)
fuse_request_init(fm, 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_req *req);
static struct fuse_req *fuse_get_req(struct fuse_mount *fm, bool for_background)
{
struct fuse_conn *fc = fm->fc;
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(fm, 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(req);
return ERR_PTR(-EOVERFLOW);
}
return req;
out:
fuse_drop_waiting(fc);
return ERR_PTR(err);
}
static void fuse_put_request(struct fuse_req *req)
{
struct fuse_conn *fc = req->fm->fc;
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_req *req)
{
struct fuse_mount *fm = req->fm;
struct fuse_conn *fc = fm->fc;
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 intr_entry check. Pairs with
* smp_mb() from queue_interrupt().
*/
if (!list_empty(&req->intr_entry)) {
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 && fm->sb) {
clear_bdi_congested(fm->sb->s_bdi, BLK_RW_SYNC);
clear_bdi_congested(fm->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(fm, req->args, req->out.h.error);
put_request:
fuse_put_request(req);
}
EXPORT_SYMBOL_GPL(fuse_request_end);
static int queue_interrupt(struct fuse_req *req)
{
struct fuse_iqueue *fiq = &req->fm->fc->iq;
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 fuse_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_req *req)
{
struct fuse_conn *fc = req->fm->fc;
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(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_req *req)
{
struct fuse_iqueue *fiq = &req->fm->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(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_req *req)
{
struct fuse_conn *fc = req->fm->fc;
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_mount *fm, struct fuse_args *args)
{
struct fuse_conn *fc = fm->fc;
struct fuse_req *req;
ssize_t ret;
if (args->force) {
atomic_inc(&fc->num_waiting);
req = fuse_request_alloc(fm, GFP_KERNEL | __GFP_NOFAIL);
if (!args->nocreds)
fuse_force_creds(req);
__set_bit(FR_WAITING, &req->flags);
__set_bit(FR_FORCE, &req->flags);
} else {
WARN_ON(args->nocreds);
req = fuse_get_req(fm, 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(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(req);
return ret;
}
static bool fuse_request_queue_background(struct fuse_req *req)
{
struct fuse_mount *fm = req->fm;
struct fuse_conn *fc = fm->fc;
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 && fm->sb) {
set_bdi_congested(fm->sb->s_bdi, BLK_RW_SYNC);
set_bdi_congested(fm->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_mount *fm, struct fuse_args *args,
gfp_t gfp_flags)
{
struct fuse_req *req;
if (args->force) {
WARN_ON(!args->nocreds);
req = fuse_request_alloc(fm, gfp_flags);
if (!req)
return -ENOMEM;
__set_bit(FR_BACKGROUND, &req->flags);
} else {
WARN_ON(args->nocreds);
req = fuse_get_req(fm, true);
if (IS_ERR(req))
return PTR_ERR(req);
}
fuse_args_to_req(req, args);
if (!fuse_request_queue_background(req)) {
fuse_put_request(req);
return -ENOTCONN;
}
return 0;
}
EXPORT_SYMBOL_GPL(fuse_simple_background);
static int fuse_simple_notify_reply(struct fuse_mount *fm,
struct fuse_args *args, u64 unique)
{
struct fuse_req *req;
struct fuse_iqueue *fiq = &fm->fc->iq;
int err = 0;
req = fuse_get_req(fm, 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(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->max_usage)
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_reclaim |
1 << PG_waiters))) {
dump_page(page, "fuse: trying to steal weird page");
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_try_steal(cs->pipe, buf))
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;
replace_page_cache_page(oldpage, newpage);
get_page(newpage);
if (!(buf->flags & PIPE_BUF_FLAG_LRU))
lru_cache_add(newpage);
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->max_usage)
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) {
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(req);
goto restart;
}
spin_lock(&fpq->lock);
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(req);
fuse_put_request(req);
return reqsize;
out_end:
if (!test_bit(FR_PRIVATE, &req->flags))
list_del_init(&req->list);
spin_unlock(&fpq->lock);
fuse_request_end(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->max_usage, 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_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) {
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 = fuse_reverse_inval_inode(fc, 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 = fuse_reverse_inval_entry(fc, 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 = fuse_reverse_inval_entry(fc, 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;
inode = fuse_ilookup(fc, nodeid, NULL);
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_mount *fm, 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_mount *fm, 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_conn *fc = fm->fc;
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(fm, args, outarg->notify_unique);
if (err)
fuse_retrieve_end(fm, 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 fuse_mount *fm;
struct inode *inode;
u64 nodeid;
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;
nodeid = outarg.nodeid;
inode = fuse_ilookup(fc, nodeid, &fm);
if (inode) {
err = fuse_retrieve(fm, 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 <= -1000 || 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(req);
fuse_put_request(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);
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(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 int head, tail, mask, count;
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);
head = pipe->head;
tail = pipe->tail;
mask = pipe->ring_size - 1;
count = head - tail;
bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL);
if (!bufs) {
pipe_unlock(pipe);
return -ENOMEM;
}
nbuf = 0;
rem = 0;
for (idx = tail; idx != head && rem < len; idx++)
rem += pipe->bufs[idx & mask].len;
ret = -EINVAL;
if (rem < len)
goto out_free;
rem = len;
while (rem) {
struct pipe_buffer *ibuf;
struct pipe_buffer *obuf;
if (WARN_ON(nbuf >= count || tail == head))
goto out_free;
ibuf = &pipe->bufs[tail & mask];
obuf = &bufs[nbuf];
if (rem >= ibuf->len) {
*obuf = *ibuf;
ibuf->ops = NULL;
tail++;
pipe->tail = tail;
} 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++)
pipe_buf_release(pipe, &bufs[idx]);
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 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(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.rst).
*
* 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(&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(&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;
if (_IOC_TYPE(cmd) != FUSE_DEV_IOC_MAGIC)
return -ENOTTY;
switch (_IOC_NR(cmd)) {
case _IOC_NR(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;
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 = compat_ptr_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);
}