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linux/fs/fuse/dev.c
Linus Torvalds a9a08845e9 vfs: do bulk POLL* -> EPOLL* replacement 
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-11 14:34:03 -08:00

2274 lines
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/*
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");
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, struct page **pages,
struct fuse_page_desc *page_descs,
unsigned npages)
{
memset(req, 0, sizeof(*req));
memset(pages, 0, sizeof(*pages) * npages);
memset(page_descs, 0, sizeof(*page_descs) * npages);
INIT_LIST_HEAD(&req->list);
INIT_LIST_HEAD(&req->intr_entry);
init_waitqueue_head(&req->waitq);
refcount_set(&req->count, 1);
req->pages = pages;
req->page_descs = page_descs;
req->max_pages = npages;
__set_bit(FR_PENDING, &req->flags);
}
static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
{
struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags);
if (req) {
struct page **pages;
struct fuse_page_desc *page_descs;
if (npages <= FUSE_REQ_INLINE_PAGES) {
pages = req->inline_pages;
page_descs = req->inline_page_descs;
} else {
pages = kmalloc(sizeof(struct page *) * npages, flags);
page_descs = kmalloc(sizeof(struct fuse_page_desc) *
npages, flags);
}
if (!pages || !page_descs) {
kfree(pages);
kfree(page_descs);
kmem_cache_free(fuse_req_cachep, req);
return NULL;
}
fuse_request_init(req, pages, page_descs, npages);
}
return req;
}
struct fuse_req *fuse_request_alloc(unsigned npages)
{
return __fuse_request_alloc(npages, GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(fuse_request_alloc);
struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
{
return __fuse_request_alloc(npages, GFP_NOFS);
}
void fuse_request_free(struct fuse_req *req)
{
if (req->pages != req->inline_pages) {
kfree(req->pages);
kfree(req->page_descs);
}
kmem_cache_free(fuse_req_cachep, req);
}
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);
}
static void fuse_req_init_context(struct fuse_conn *fc, struct fuse_req *req)
{
req->in.h.uid = from_kuid_munged(&init_user_ns, current_fsuid());
req->in.h.gid = from_kgid_munged(&init_user_ns, current_fsgid());
req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
}
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 struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
bool for_background)
{
struct fuse_req *req;
int err;
atomic_inc(&fc->num_waiting);
if (fuse_block_alloc(fc, for_background)) {
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(npages);
err = -ENOMEM;
if (!req) {
if (for_background)
wake_up(&fc->blocked_waitq);
goto out;
}
fuse_req_init_context(fc, req);
__set_bit(FR_WAITING, &req->flags);
if (for_background)
__set_bit(FR_BACKGROUND, &req->flags);
return req;
out:
atomic_dec(&fc->num_waiting);
return ERR_PTR(err);
}
struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
{
return __fuse_get_req(fc, npages, false);
}
EXPORT_SYMBOL_GPL(fuse_get_req);
struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
unsigned npages)
{
return __fuse_get_req(fc, npages, true);
}
EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
/*
* Return request in fuse_file->reserved_req. However that may
* currently be in use. If that is the case, wait for it to become
* available.
*/
static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
struct file *file)
{
struct fuse_req *req = NULL;
struct fuse_file *ff = file->private_data;
do {
wait_event(fc->reserved_req_waitq, ff->reserved_req);
spin_lock(&fc->lock);
if (ff->reserved_req) {
req = ff->reserved_req;
ff->reserved_req = NULL;
req->stolen_file = get_file(file);
}
spin_unlock(&fc->lock);
} while (!req);
return req;
}
/*
* Put stolen request back into fuse_file->reserved_req
*/
static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
{
struct file *file = req->stolen_file;
struct fuse_file *ff = file->private_data;
spin_lock(&fc->lock);
fuse_request_init(req, req->pages, req->page_descs, req->max_pages);
BUG_ON(ff->reserved_req);
ff->reserved_req = req;
wake_up_all(&fc->reserved_req_waitq);
spin_unlock(&fc->lock);
fput(file);
}
/*
* Gets a requests for a file operation, always succeeds
*
* This is used for sending the FLUSH request, which must get to
* userspace, due to POSIX locks which may need to be unlocked.
*
* If allocation fails due to OOM, use the reserved request in
* fuse_file.
*
* This is very unlikely to deadlock accidentally, since the
* filesystem should not have it's own file open. If deadlock is
* intentional, it can still be broken by "aborting" the filesystem.
*/
struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
struct file *file)
{
struct fuse_req *req;
atomic_inc(&fc->num_waiting);
wait_event(fc->blocked_waitq, fc->initialized);
/* Matches smp_wmb() in fuse_set_initialized() */
smp_rmb();
req = fuse_request_alloc(0);
if (!req)
req = get_reserved_req(fc, file);
fuse_req_init_context(fc, req);
__set_bit(FR_WAITING, &req->flags);
__clear_bit(FR_BACKGROUND, &req->flags);
return req;
}
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->lock);
if (!fc->blocked)
wake_up(&fc->blocked_waitq);
spin_unlock(&fc->lock);
}
if (test_bit(FR_WAITING, &req->flags)) {
__clear_bit(FR_WAITING, &req->flags);
atomic_dec(&fc->num_waiting);
}
if (req->stolen_file)
put_reserved_req(fc, req);
else
fuse_request_free(req);
}
}
EXPORT_SYMBOL_GPL(fuse_put_request);
static unsigned len_args(unsigned numargs, struct fuse_arg *args)
{
unsigned nbytes = 0;
unsigned i;
for (i = 0; i < numargs; i++)
nbytes += args[i].size;
return nbytes;
}
static u64 fuse_get_unique(struct fuse_iqueue *fiq)
{
return ++fiq->reqctr;
}
static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req)
{
req->in.h.len = sizeof(struct fuse_in_header) +
len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
list_add_tail(&req->list, &fiq->pending);
wake_up_locked(&fiq->waitq);
kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
}
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->waitq.lock);
if (fiq->connected) {
fiq->forget_list_tail->next = forget;
fiq->forget_list_tail = forget;
wake_up_locked(&fiq->waitq);
kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
} else {
kfree(forget);
}
spin_unlock(&fiq->waitq.lock);
}
static void flush_bg_queue(struct fuse_conn *fc)
{
while (fc->active_background < fc->max_background &&
!list_empty(&fc->bg_queue)) {
struct fuse_req *req;
struct fuse_iqueue *fiq = &fc->iq;
req = list_entry(fc->bg_queue.next, struct fuse_req, list);
list_del(&req->list);
fc->active_background++;
spin_lock(&fiq->waitq.lock);
req->in.h.unique = fuse_get_unique(fiq);
queue_request(fiq, req);
spin_unlock(&fiq->waitq.lock);
}
}
/*
* 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
*/
static void 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))
return;
spin_lock(&fiq->waitq.lock);
list_del_init(&req->intr_entry);
spin_unlock(&fiq->waitq.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->lock);
clear_bit(FR_BACKGROUND, &req->flags);
if (fc->num_background == fc->max_background)
fc->blocked = 0;
/* Wake up next waiter, if any */
if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
wake_up(&fc->blocked_waitq);
if (fc->num_background == fc->congestion_threshold &&
fc->connected && fc->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->lock);
}
wake_up(&req->waitq);
if (req->end)
req->end(fc, req);
fuse_put_request(fc, req);
}
static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
{
spin_lock(&fiq->waitq.lock);
if (test_bit(FR_FINISHED, &req->flags)) {
spin_unlock(&fiq->waitq.lock);
return;
}
if (list_empty(&req->intr_entry)) {
list_add_tail(&req->intr_entry, &fiq->interrupts);
wake_up_locked(&fiq->waitq);
}
spin_unlock(&fiq->waitq.lock);
kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
}
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->waitq.lock);
/* Request is not yet in userspace, bail out */
if (test_bit(FR_PENDING, &req->flags)) {
list_del(&req->list);
spin_unlock(&fiq->waitq.lock);
__fuse_put_request(req);
req->out.h.error = -EINTR;
return;
}
spin_unlock(&fiq->waitq.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->waitq.lock);
if (!fiq->connected) {
spin_unlock(&fiq->waitq.lock);
req->out.h.error = -ENOTCONN;
} else {
req->in.h.unique = fuse_get_unique(fiq);
queue_request(fiq, req);
/* acquire extra reference, since request is still needed
after request_end() */
__fuse_get_request(req);
spin_unlock(&fiq->waitq.lock);
request_wait_answer(fc, req);
/* Pairs with smp_wmb() in request_end() */
smp_rmb();
}
}
void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
{
__set_bit(FR_ISREPLY, &req->flags);
if (!test_bit(FR_WAITING, &req->flags)) {
__set_bit(FR_WAITING, &req->flags);
atomic_inc(&fc->num_waiting);
}
__fuse_request_send(fc, req);
}
EXPORT_SYMBOL_GPL(fuse_request_send);
static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
{
if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
if (fc->minor < 9) {
switch (args->in.h.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->in.h.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;
}
}
}
ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
{
struct fuse_req *req;
ssize_t ret;
req = fuse_get_req(fc, 0);
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);
req->in.h.opcode = args->in.h.opcode;
req->in.h.nodeid = args->in.h.nodeid;
req->in.numargs = args->in.numargs;
memcpy(req->in.args, args->in.args,
args->in.numargs * sizeof(struct fuse_in_arg));
req->out.argvar = args->out.argvar;
req->out.numargs = args->out.numargs;
memcpy(req->out.args, args->out.args,
args->out.numargs * sizeof(struct fuse_arg));
fuse_request_send(fc, req);
ret = req->out.h.error;
if (!ret && args->out.argvar) {
BUG_ON(args->out.numargs != 1);
ret = req->out.args[0].size;
}
fuse_put_request(fc, req);
return ret;
}
/*
* Called under fc->lock
*
* fc->connected must have been checked previously
*/
void fuse_request_send_background_locked(struct fuse_conn *fc,
struct fuse_req *req)
{
BUG_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);
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);
}
void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
{
BUG_ON(!req->end);
spin_lock(&fc->lock);
if (fc->connected) {
fuse_request_send_background_locked(fc, req);
spin_unlock(&fc->lock);
} else {
spin_unlock(&fc->lock);
req->out.h.error = -ENOTCONN;
req->end(fc, req);
fuse_put_request(fc, req);
}
}
EXPORT_SYMBOL_GPL(fuse_request_send_background);
static int fuse_request_send_notify_reply(struct fuse_conn *fc,
struct fuse_req *req, u64 unique)
{
int err = -ENODEV;
struct fuse_iqueue *fiq = &fc->iq;
__clear_bit(FR_ISREPLY, &req->flags);
req->in.h.unique = unique;
spin_lock(&fiq->waitq.lock);
if (fiq->connected) {
queue_request(fiq, req);
err = 0;
}
spin_unlock(&fiq->waitq.lock);
return err;
}
void fuse_force_forget(struct file *file, u64 nodeid)
{
struct inode *inode = file_inode(file);
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_req *req;
struct fuse_forget_in inarg;
memset(&inarg, 0, sizeof(inarg));
inarg.nlookup = 1;
req = fuse_get_req_nofail_nopages(fc, file);
req->in.h.opcode = FUSE_FORGET;
req->in.h.nodeid = nodeid;
req->in.numargs = 1;
req->in.args[0].size = sizeof(inarg);
req->in.args[0].value = &inarg;
__clear_bit(FR_ISREPLY, &req->flags);
__fuse_request_send(fc, req);
/* ignore errors */
fuse_put_request(fc, req);
}
/*
* Lock the request. Up to the next unlock_request() there mustn't be
* anything that could cause a page-fault. If the request was already
* aborted bail out.
*/
static int lock_request(struct fuse_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_count(page) != 1 ||
(page->flags & PAGE_FLAGS_CHECK_AT_PREP &
~(1 << PG_locked |
1 << PG_referenced |
1 << PG_uptodate |
1 << PG_lru |
1 << PG_active |
1 << PG_reclaim))) {
printk(KERN_WARNING "fuse: trying to steal weird page\n");
printk(KERN_WARNING " page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);
return 1;
}
return 0;
}
static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
{
int err;
struct page *oldpage = *pagep;
struct page *newpage;
struct pipe_buffer *buf = cs->pipebufs;
err = unlock_request(cs->req);
if (err)
return err;
fuse_copy_finish(cs);
err = pipe_buf_confirm(cs->pipe, buf);
if (err)
return err;
BUG_ON(!cs->nr_segs);
cs->currbuf = buf;
cs->len = buf->len;
cs->pipebufs++;
cs->nr_segs--;
if (cs->len != PAGE_SIZE)
goto out_fallback;
if (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);
return err;
}
get_page(newpage);
if (!(buf->flags & PIPE_BUF_FLAG_LRU))
lru_cache_add_file(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);
return err;
}
unlock_page(oldpage);
put_page(oldpage);
cs->len = 0;
return 0;
out_fallback_unlock:
unlock_page(newpage);
out_fallback:
cs->pg = buf->page;
cs->offset = buf->offset;
err = lock_request(cs->req);
if (err)
return err;
return 1;
}
static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
unsigned offset, unsigned count)
{
struct pipe_buffer *buf;
int err;
if (cs->nr_segs == cs->pipe->buffers)
return -EIO;
err = unlock_request(cs->req);
if (err)
return err;
fuse_copy_finish(cs);
buf = cs->pipebufs;
get_page(page);
buf->page = page;
buf->offset = offset;
buf->len = count;
cs->pipebufs++;
cs->nr_segs++;
cs->len = 0;
return 0;
}
/*
* Copy a page in the request to/from the userspace buffer. Must be
* done atomically
*/
static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
unsigned offset, unsigned count, int zeroing)
{
int err;
struct page *page = *pagep;
if (page && zeroing && count < PAGE_SIZE)
clear_highpage(page);
while (count) {
if (cs->write && cs->pipebufs && page) {
return fuse_ref_page(cs, page, offset, count);
} else if (!cs->len) {
if (cs->move_pages && page &&
offset == 0 && count == PAGE_SIZE) {
err = fuse_try_move_page(cs, pagep);
if (err <= 0)
return err;
} else {
err = fuse_copy_fill(cs);
if (err)
return err;
}
}
if (page) {
void *mapaddr = kmap_atomic(page);
void *buf = mapaddr + offset;
offset += fuse_copy_do(cs, &buf, &count);
kunmap_atomic(mapaddr);
} else
offset += fuse_copy_do(cs, NULL, &count);
}
if (page && !cs->write)
flush_dcache_page(page);
return 0;
}
/* Copy pages in the request to/from userspace buffer */
static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
int zeroing)
{
unsigned i;
struct fuse_req *req = cs->req;
for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
int err;
unsigned offset = req->page_descs[i].offset;
unsigned count = min(nbytes, req->page_descs[i].length);
err = fuse_copy_page(cs, &req->pages[i], offset, count,
zeroing);
if (err)
return err;
nbytes -= count;
}
return 0;
}
/* Copy a single argument in the request to/from userspace buffer */
static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
{
while (size) {
if (!cs->len) {
int err = fuse_copy_fill(cs);
if (err)
return err;
}
fuse_copy_do(cs, &val, &size);
}
return 0;
}
/* Copy request arguments to/from userspace buffer */
static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
unsigned argpages, struct fuse_arg *args,
int zeroing)
{
int err = 0;
unsigned i;
for (i = 0; !err && i < numargs; i++) {
struct fuse_arg *arg = &args[i];
if (i == numargs - 1 && argpages)
err = fuse_copy_pages(cs, arg->size, zeroing);
else
err = fuse_copy_one(cs, arg->value, arg->size);
}
return err;
}
static int forget_pending(struct fuse_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->waitq.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->waitq.lock)
{
struct fuse_in_header ih;
struct fuse_interrupt_in arg;
unsigned reqsize = sizeof(ih) + sizeof(arg);
int err;
list_del_init(&req->intr_entry);
req->intr_unique = fuse_get_unique(fiq);
memset(&ih, 0, sizeof(ih));
memset(&arg, 0, sizeof(arg));
ih.len = reqsize;
ih.opcode = FUSE_INTERRUPT;
ih.unique = req->intr_unique;
arg.unique = req->in.h.unique;
spin_unlock(&fiq->waitq.lock);
if (nbytes < reqsize)
return -EINVAL;
err = fuse_copy_one(cs, &ih, sizeof(ih));
if (!err)
err = fuse_copy_one(cs, &arg, sizeof(arg));
fuse_copy_finish(cs);
return err ? err : reqsize;
}
static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
unsigned max,
unsigned *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;
}
static int fuse_read_single_forget(struct fuse_iqueue *fiq,
struct fuse_copy_state *cs,
size_t nbytes)
__releases(fiq->waitq.lock)
{
int err;
struct fuse_forget_link *forget = 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->waitq.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->waitq.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->waitq.lock);
return -EINVAL;
}
max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
head = dequeue_forget(fiq, max_forgets, &count);
spin_unlock(&fiq->waitq.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->waitq.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
* 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_in *in;
unsigned reqsize;
restart:
spin_lock(&fiq->waitq.lock);
err = -EAGAIN;
if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
!request_pending(fiq))
goto err_unlock;
err = wait_event_interruptible_exclusive_locked(fiq->waitq,
!fiq->connected || request_pending(fiq));
if (err)
goto err_unlock;
err = -ENODEV;
if (!fiq->connected)
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->waitq.lock);
in = &req->in;
reqsize = in->h.len;
if (task_active_pid_ns(current) != fc->pid_ns) {
rcu_read_lock();
in->h.pid = pid_vnr(find_pid_ns(in->h.pid, fc->pid_ns));
rcu_read_unlock();
}
/* If request is too large, reply with an error and restart the read */
if (nbytes < reqsize) {
req->out.h.error = -EIO;
/* SETXATTR is special, since it may contain too large data */
if (in->h.opcode == FUSE_SETXATTR)
req->out.h.error = -E2BIG;
request_end(fc, req);
goto restart;
}
spin_lock(&fpq->lock);
list_add(&req->list, &fpq->io);
spin_unlock(&fpq->lock);
cs->req = req;
err = fuse_copy_one(cs, &in->h, sizeof(in->h));
if (!err)
err = fuse_copy_args(cs, in->numargs, in->argpages,
(struct fuse_arg *) in->args, 0);
fuse_copy_finish(cs);
spin_lock(&fpq->lock);
clear_bit(FR_LOCKED, &req->flags);
if (!fpq->connected) {
err = -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;
}
list_move_tail(&req->list, &fpq->processing);
spin_unlock(&fpq->lock);
set_bit(FR_SENT, &req->flags);
/* matches barrier in request_wait_answer() */
smp_mb__after_atomic();
if (test_bit(FR_INTERRUPTED, &req->flags))
queue_interrupt(fiq, req);
return reqsize;
out_end:
if (!test_bit(FR_PRIVATE, &req->flags))
list_del_init(&req->list);
spin_unlock(&fpq->lock);
request_end(fc, req);
return err;
err_unlock:
spin_unlock(&fiq->waitq.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 = kmalloc(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);
kfree(bufs);
return ret;
}
static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
struct fuse_copy_state *cs)
{
struct fuse_notify_poll_wakeup_out outarg;
int err = -EINVAL;
if (size != sizeof(outarg))
goto err;
err = fuse_copy_one(cs, &outarg, sizeof(outarg));
if (err)
goto err;
fuse_copy_finish(cs);
return fuse_notify_poll_wakeup(fc, &outarg);
err:
fuse_copy_finish(cs);
return err;
}
static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
struct fuse_copy_state *cs)
{
struct fuse_notify_inval_inode_out outarg;
int err = -EINVAL;
if (size != sizeof(outarg))
goto err;
err = fuse_copy_one(cs, &outarg, sizeof(outarg));
if (err)
goto err;
fuse_copy_finish(cs);
down_read(&fc->killsb);
err = -ENOENT;
if (fc->sb) {
err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
outarg.off, outarg.len);
}
up_read(&fc->killsb);
return err;
err:
fuse_copy_finish(cs);
return err;
}
static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
struct fuse_copy_state *cs)
{
struct fuse_notify_inval_entry_out outarg;
int err = -ENOMEM;
char *buf;
struct qstr name;
buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
if (!buf)
goto err;
err = -EINVAL;
if (size < sizeof(outarg))
goto err;
err = fuse_copy_one(cs, &outarg, sizeof(outarg));
if (err)
goto err;
err = -ENAMETOOLONG;
if (outarg.namelen > FUSE_NAME_MAX)
goto err;
err = -EINVAL;
if (size != sizeof(outarg) + outarg.namelen + 1)
goto err;
name.name = buf;
name.len = outarg.namelen;
err = fuse_copy_one(cs, buf, outarg.namelen + 1);
if (err)
goto err;
fuse_copy_finish(cs);
buf[outarg.namelen] = 0;
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;
}
static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
{
release_pages(req->pages, req->num_pages);
}
static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
struct fuse_notify_retrieve_out *outarg)
{
int err;
struct address_space *mapping = inode->i_mapping;
struct fuse_req *req;
pgoff_t index;
loff_t file_size;
unsigned int num;
unsigned int offset;
size_t total_len = 0;
int num_pages;
offset = outarg->offset & ~PAGE_MASK;
file_size = i_size_read(inode);
num = outarg->size;
if (outarg->offset > file_size)
num = 0;
else if (outarg->offset + num > file_size)
num = file_size - outarg->offset;
num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
req = fuse_get_req(fc, num_pages);
if (IS_ERR(req))
return PTR_ERR(req);
req->in.h.opcode = FUSE_NOTIFY_REPLY;
req->in.h.nodeid = outarg->nodeid;
req->in.numargs = 2;
req->in.argpages = 1;
req->page_descs[0].offset = offset;
req->end = fuse_retrieve_end;
index = outarg->offset >> PAGE_SHIFT;
while (num && req->num_pages < num_pages) {
struct page *page;
unsigned int this_num;
page = find_get_page(mapping, index);
if (!page)
break;
this_num = min_t(unsigned, num, PAGE_SIZE - offset);
req->pages[req->num_pages] = page;
req->page_descs[req->num_pages].length = this_num;
req->num_pages++;
offset = 0;
num -= this_num;
total_len += this_num;
index++;
}
req->misc.retrieve_in.offset = outarg->offset;
req->misc.retrieve_in.size = total_len;
req->in.args[0].size = sizeof(req->misc.retrieve_in);
req->in.args[0].value = &req->misc.retrieve_in;
req->in.args[1].size = total_len;
err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
if (err)
fuse_retrieve_end(fc, req);
return err;
}
static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
struct fuse_copy_state *cs)
{
struct fuse_notify_retrieve_out outarg;
struct inode *inode;
int err;
err = -EINVAL;
if (size != sizeof(outarg))
goto copy_finish;
err = fuse_copy_one(cs, &outarg, sizeof(outarg));
if (err)
goto copy_finish;
fuse_copy_finish(cs);
down_read(&fc->killsb);
err = -ENOENT;
if (fc->sb) {
u64 nodeid = outarg.nodeid;
inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
if (inode) {
err = fuse_retrieve(fc, inode, &outarg);
iput(inode);
}
}
up_read(&fc->killsb);
return err;
copy_finish:
fuse_copy_finish(cs);
return err;
}
static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
unsigned int size, struct fuse_copy_state *cs)
{
/* 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)
{
struct fuse_req *req;
list_for_each_entry(req, &fpq->processing, list) {
if (req->in.h.unique == unique || req->intr_unique == unique)
return req;
}
return NULL;
}
static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
unsigned nbytes)
{
unsigned reqsize = sizeof(struct fuse_out_header);
if (out->h.error)
return nbytes != reqsize ? -EINVAL : 0;
reqsize += len_args(out->numargs, out->args);
if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
return -EINVAL;
else if (reqsize > nbytes) {
struct fuse_arg *lastarg = &out->args[out->numargs-1];
unsigned diffsize = reqsize - nbytes;
if (diffsize > lastarg->size)
return -EINVAL;
lastarg->size -= diffsize;
}
return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
out->page_zeroing);
}
/*
* Write a single reply to a request. First the header is copied from
* the write buffer. The request is then searched on the processing
* list by the unique ID found in the header. If found, then remove
* it from the list and copy the rest of the buffer to the request.
* The request is finished by calling request_end()
*/
static ssize_t fuse_dev_do_write(struct fuse_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;
if (nbytes < sizeof(struct fuse_out_header))
return -EINVAL;
err = fuse_copy_one(cs, &oh, sizeof(oh));
if (err)
goto err_finish;
err = -EINVAL;
if (oh.len != nbytes)
goto err_finish;
/*
* Zero oh.unique indicates unsolicited notification message
* and error contains notification code.
*/
if (!oh.unique) {
err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
return err ? err : nbytes;
}
err = -EINVAL;
if (oh.error <= -1000 || oh.error > 0)
goto err_finish;
spin_lock(&fpq->lock);
err = -ENOENT;
if (!fpq->connected)
goto err_unlock_pq;
req = request_find(fpq, oh.unique);
if (!req)
goto err_unlock_pq;
/* Is it an interrupt reply? */
if (req->intr_unique == oh.unique) {
spin_unlock(&fpq->lock);
err = -EINVAL;
if (nbytes != sizeof(struct fuse_out_header))
goto err_finish;
if (oh.error == -ENOSYS)
fc->no_interrupt = 1;
else if (oh.error == -EAGAIN)
queue_interrupt(&fc->iq, req);
fuse_copy_finish(cs);
return nbytes;
}
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->out.page_replace)
cs->move_pages = 0;
err = copy_out_args(cs, &req->out, 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);
request_end(fc, req);
return err ? err : nbytes;
err_unlock_pq:
spin_unlock(&fpq->lock);
err_finish:
fuse_copy_finish(cs);
return err;
}
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;
bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
if (!bufs)
return -ENOMEM;
pipe_lock(pipe);
nbuf = 0;
rem = 0;
for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
ret = -EINVAL;
if (rem < len) {
pipe_unlock(pipe);
goto out;
}
rem = len;
while (rem) {
struct pipe_buffer *ibuf;
struct pipe_buffer *obuf;
BUG_ON(nbuf >= pipe->buffers);
BUG_ON(!pipe->nrbufs);
ibuf = &pipe->bufs[pipe->curbuf];
obuf = &bufs[nbuf];
if (rem >= ibuf->len) {
*obuf = *ibuf;
ibuf->ops = NULL;
pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
pipe->nrbufs--;
} else {
pipe_buf_get(pipe, ibuf);
*obuf = *ibuf;
obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
obuf->len = rem;
ibuf->offset += obuf->len;
ibuf->len -= obuf->len;
}
nbuf++;
rem -= obuf->len;
}
pipe_unlock(pipe);
fuse_copy_init(&cs, 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);
for (idx = 0; idx < nbuf; idx++)
pipe_buf_release(pipe, &bufs[idx]);
out:
kfree(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->waitq.lock);
if (!fiq->connected)
mask = EPOLLERR;
else if (request_pending(fiq))
mask |= EPOLLIN | EPOLLRDNORM;
spin_unlock(&fiq->waitq.lock);
return mask;
}
/*
* Abort all requests on the given list (pending or processing)
*
* This function releases and reacquires fc->lock
*/
static void end_requests(struct fuse_conn *fc, struct list_head *head)
{
while (!list_empty(head)) {
struct fuse_req *req;
req = list_entry(head->next, struct fuse_req, list);
req->out.h.error = -ECONNABORTED;
clear_bit(FR_SENT, &req->flags);
list_del_init(&req->list);
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_end1);
LIST_HEAD(to_end2);
fc->connected = 0;
fc->blocked = 0;
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);
list_move(&req->list, &to_end1);
}
spin_unlock(&req->waitq.lock);
}
list_splice_init(&fpq->processing, &to_end2);
spin_unlock(&fpq->lock);
}
fc->max_background = UINT_MAX;
flush_bg_queue(fc);
spin_lock(&fiq->waitq.lock);
fiq->connected = 0;
list_splice_init(&fiq->pending, &to_end2);
list_for_each_entry(req, &to_end2, list)
clear_bit(FR_PENDING, &req->flags);
while (forget_pending(fiq))
kfree(dequeue_forget(fiq, 1, NULL));
wake_up_all_locked(&fiq->waitq);
spin_unlock(&fiq->waitq.lock);
kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
end_polls(fc);
wake_up_all(&fc->blocked_waitq);
spin_unlock(&fc->lock);
while (!list_empty(&to_end1)) {
req = list_first_entry(&to_end1, struct fuse_req, list);
__fuse_get_request(req);
list_del_init(&req->list);
request_end(fc, req);
}
end_requests(fc, &to_end2);
} else {
spin_unlock(&fc->lock);
}
}
EXPORT_SYMBOL_GPL(fuse_abort_conn);
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;
WARN_ON(!list_empty(&fpq->io));
end_requests(fc, &fpq->processing);
/* 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(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 err = -ENOTTY;
if (cmd == FUSE_DEV_IOC_CLONE) {
int oldfd;
err = -EFAULT;
if (!get_user(oldfd, (__u32 __user *) arg)) {
struct file *old = fget(oldfd);
err = -EINVAL;
if (old) {
struct fuse_dev *fud = NULL;
/*
* 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);
err = fuse_device_clone(fud->fc, file);
mutex_unlock(&fuse_mutex);
}
fput(old);
}
}
}
return err;
}
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);
}
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