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-rw-r--r--fs/fuse/dev.c2460
1 files changed, 2460 insertions, 0 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
new file mode 100644
index 000000000..4fec31fc0
--- /dev/null
+++ b/fs/fuse/dev.c
@@ -0,0 +1,2460 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ FUSE: Filesystem in Userspace
+ Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
+*/
+
+#include "dev.h"
+#include "args.h"
+#include "dev_uring_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>
+#include <linux/seq_file.h>
+
+#include "fuse_trace.h"
+
+MODULE_ALIAS_MISCDEV(FUSE_MINOR);
+MODULE_ALIAS("devname:fuse");
+
+static DECLARE_WAIT_QUEUE_HEAD(fuse_dev_waitq);
+
+static struct kmem_cache *fuse_req_cachep;
+
+static void fuse_request_init(struct fuse_chan *fch, 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->chan = fch;
+ req->create_time = jiffies;
+}
+
+static struct fuse_req *fuse_request_alloc(struct fuse_chan *fch, gfp_t flags)
+{
+ struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags);
+ if (req)
+ fuse_request_init(fch, req);
+
+ return req;
+}
+
+static void fuse_request_free(struct fuse_req *req)
+{
+ WARN_ON(!list_empty(&req->intr_entry));
+ 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_chan_set_initialized(struct fuse_chan *fch, struct fuse_chan_param *param)
+{
+ if (param) {
+ fch->minor = param->minor;
+ fch->max_write = param->max_write;
+ fch->max_pages = param->max_pages;
+
+ if (param->io_uring_enabled)
+ fuse_uring_conn_init(fch);
+ }
+
+ /* Pairs with smp_load_acquire() readers of fch->initialized */
+ smp_store_release(&fch->initialized, 1);
+ wake_up_all(&fch->blocked_waitq);
+}
+
+static bool fuse_block_alloc(struct fuse_chan *fch, bool for_background)
+{
+ /* Pairs with smp_store_release() in fuse_chan_set_initialized() */
+ if (!smp_load_acquire(&fch->initialized))
+ return true;
+
+ return (for_background && fch->blocked) ||
+ (fch->io_uring && fch->connected && !fuse_uring_ready(fch));
+}
+
+static void fuse_drop_waiting(struct fuse_chan *fch)
+{
+ /*
+ * lockess check of fch->connected is okay, because atomic_dec_and_test()
+ * provides a memory barrier matched with the one in fuse_chan_wait_aborted()
+ * to ensure no wake-up is missed.
+ */
+ if (atomic_dec_and_test(&fch->num_waiting) &&
+ !READ_ONCE(fch->connected)) {
+ /* wake up aborters */
+ wake_up_all(&fch->blocked_waitq);
+ }
+}
+
+static void fuse_put_request(struct fuse_req *req);
+
+static struct fuse_req *fuse_get_req(struct fuse_chan *fch, bool for_background)
+{
+ struct fuse_req *req;
+ int err;
+
+ atomic_inc(&fch->num_waiting);
+
+ if (fuse_block_alloc(fch, for_background)) {
+ err = -EINTR;
+ if (wait_event_state_exclusive(fch->blocked_waitq,
+ !fuse_block_alloc(fch, for_background),
+ (TASK_KILLABLE | TASK_FREEZABLE)))
+ goto out;
+ }
+
+ err = -ENOTCONN;
+ if (!fch->connected)
+ goto out;
+
+ req = fuse_request_alloc(fch, GFP_KERNEL);
+ err = -ENOMEM;
+ if (!req) {
+ if (for_background)
+ wake_up(&fch->blocked_waitq);
+ goto out;
+ }
+
+ __set_bit(FR_WAITING, &req->flags);
+ if (for_background)
+ __set_bit(FR_BACKGROUND, &req->flags);
+
+ return req;
+
+ out:
+ fuse_drop_waiting(fch);
+ return ERR_PTR(err);
+}
+
+static void fuse_put_request(struct fuse_req *req)
+{
+ struct fuse_chan *fch = req->chan;
+
+ 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(&fch->bg_lock);
+ if (!fch->blocked)
+ wake_up(&fch->blocked_waitq);
+ spin_unlock(&fch->bg_lock);
+ }
+
+ if (test_bit(FR_WAITING, &req->flags)) {
+ __clear_bit(FR_WAITING, &req->flags);
+ fuse_drop_waiting(fch);
+ }
+
+ 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);
+
+static u64 fuse_get_unique_locked(struct fuse_iqueue *fiq)
+{
+ fiq->reqctr += FUSE_REQ_ID_STEP;
+ return fiq->reqctr;
+}
+
+u64 fuse_get_unique(struct fuse_iqueue *fiq)
+{
+ u64 ret;
+
+ spin_lock(&fiq->lock);
+ ret = fuse_get_unique_locked(fiq);
+ spin_unlock(&fiq->lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(fuse_get_unique);
+
+unsigned int fuse_req_hash(u64 unique)
+{
+ return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS);
+}
+EXPORT_SYMBOL_GPL(fuse_req_hash);
+
+/*
+ * A new request is available, wake fiq->waitq
+ */
+static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq, bool sync)
+__releases(fiq->lock)
+{
+ if (sync)
+ wake_up_sync(&fiq->waitq);
+ else
+ wake_up(&fiq->waitq);
+ kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
+ spin_unlock(&fiq->lock);
+}
+
+struct fuse_forget_link *fuse_alloc_forget(void)
+{
+ return kzalloc_obj(struct fuse_forget_link, GFP_KERNEL_ACCOUNT);
+}
+
+void fuse_dev_queue_forget(struct fuse_iqueue *fiq,
+ struct fuse_forget_link *forget)
+{
+ spin_lock(&fiq->lock);
+ if (fiq->connected) {
+ fiq->forget_list_tail->next = forget;
+ fiq->forget_list_tail = forget;
+ fuse_dev_wake_and_unlock(fiq, false);
+ } else {
+ kfree(forget);
+ spin_unlock(&fiq->lock);
+ }
+}
+
+void fuse_dev_queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
+{
+ spin_lock(&fiq->lock);
+ /* Repeat FR_SENT test after obtaining the lock to prevent race with fuse_resend() */
+ if (list_empty(&req->intr_entry) && test_bit(FR_SENT, &req->flags)) {
+ 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);
+ } else {
+ fuse_dev_wake_and_unlock(fiq, false);
+ }
+ } else {
+ spin_unlock(&fiq->lock);
+ }
+}
+
+static inline void fuse_request_assign_unique_locked(struct fuse_iqueue *fiq,
+ struct fuse_req *req)
+{
+ if (req->in.h.opcode != FUSE_NOTIFY_REPLY)
+ req->in.h.unique = fuse_get_unique_locked(fiq);
+
+ /* tracepoint captures in.h.unique and in.h.len */
+ trace_fuse_request_send(req);
+}
+
+inline void fuse_request_assign_unique(struct fuse_iqueue *fiq,
+ struct fuse_req *req)
+{
+ if (req->in.h.opcode != FUSE_NOTIFY_REPLY)
+ req->in.h.unique = fuse_get_unique(fiq);
+
+ /* tracepoint captures in.h.unique and in.h.len */
+ trace_fuse_request_send(req);
+}
+EXPORT_SYMBOL_GPL(fuse_request_assign_unique);
+
+static void fuse_dev_queue_req(struct fuse_iqueue *fiq, struct fuse_req *req)
+{
+ bool sync = test_and_clear_bit(FR_SYNC_WAKEUP, &req->flags);
+
+ spin_lock(&fiq->lock);
+ if (fiq->connected) {
+ fuse_request_assign_unique_locked(fiq, req);
+ list_add_tail(&req->list, &fiq->pending);
+ fuse_dev_wake_and_unlock(fiq, sync);
+ } else {
+ spin_unlock(&fiq->lock);
+ req->out.h.error = -ENOTCONN;
+ clear_bit(FR_PENDING, &req->flags);
+ fuse_request_end(req);
+ }
+}
+
+static const struct fuse_iqueue_ops fuse_dev_fiq_ops = {
+ .send_forget = fuse_dev_queue_forget,
+ .send_interrupt = fuse_dev_queue_interrupt,
+ .send_req = fuse_dev_queue_req,
+};
+
+void fuse_iqueue_init(struct fuse_iqueue *fiq, const struct fuse_iqueue_ops *ops, void *priv)
+{
+ spin_lock_init(&fiq->lock);
+ init_waitqueue_head(&fiq->waitq);
+ INIT_LIST_HEAD(&fiq->pending);
+ INIT_LIST_HEAD(&fiq->interrupts);
+ fiq->forget_list_tail = &fiq->forget_list_head;
+ fiq->connected = 1;
+ fiq->ops = ops;
+ fiq->priv = priv;
+}
+EXPORT_SYMBOL_GPL(fuse_iqueue_init);
+
+void fuse_chan_release(struct fuse_chan *fch)
+{
+ struct fuse_iqueue *fiq = &fch->iq;
+
+ if (fiq->ops->release)
+ fiq->ops->release(fiq);
+
+ if (fch->timeout.req_timeout)
+ cancel_delayed_work_sync(&fch->timeout.work);
+}
+
+void fuse_chan_free(struct fuse_chan *fch)
+{
+ WARN_ON(!list_empty(&fch->devices));
+ kfree(fch->pq_prealloc);
+ kfree(fch);
+}
+EXPORT_SYMBOL_GPL(fuse_chan_free);
+
+struct fuse_chan *fuse_chan_new(void)
+{
+ struct fuse_chan *fch = kzalloc_obj(struct fuse_chan);
+ if (!fch)
+ return NULL;
+
+ spin_lock_init(&fch->lock);
+ INIT_LIST_HEAD(&fch->devices);
+ spin_lock_init(&fch->bg_lock);
+ INIT_LIST_HEAD(&fch->bg_queue);
+ init_waitqueue_head(&fch->blocked_waitq);
+ atomic_set(&fch->num_waiting, 0);
+ fch->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
+ fch->initialized = 0;
+ fch->blocked = 0;
+ fch->connected = 1;
+ fch->timeout.req_timeout = 0;
+
+ return fch;
+}
+EXPORT_SYMBOL_GPL(fuse_chan_new);
+
+struct list_head *fuse_pqueue_alloc(void)
+{
+ struct list_head *pq = kzalloc_objs(struct list_head, FUSE_PQ_HASH_SIZE);
+
+ if (pq) {
+ for (int i = 0; i < FUSE_PQ_HASH_SIZE; i++)
+ INIT_LIST_HEAD(&pq[i]);
+ }
+ return pq;
+}
+
+struct fuse_chan *fuse_dev_chan_new(void)
+{
+ struct fuse_chan *fch __free(kfree) = fuse_chan_new();
+ if (!fch)
+ return NULL;
+
+ fch->pq_prealloc = fuse_pqueue_alloc();
+ if (!fch->pq_prealloc)
+ return NULL;
+
+ fuse_iqueue_init(&fch->iq, &fuse_dev_fiq_ops, NULL);
+
+ return no_free_ptr(fch);
+}
+EXPORT_SYMBOL_GPL(fuse_dev_chan_new);
+
+unsigned int fuse_chan_num_background(struct fuse_chan *fch)
+{
+ return READ_ONCE(fch->num_background);
+}
+
+unsigned int fuse_chan_max_background(struct fuse_chan *fch)
+{
+ return READ_ONCE(fch->max_background);
+}
+
+void fuse_chan_max_background_set(struct fuse_chan *fch, unsigned int val)
+{
+ spin_lock(&fch->bg_lock);
+ fch->max_background = val;
+ fch->blocked = fch->num_background >= fch->max_background;
+ if (!fch->blocked)
+ wake_up_nr(&fch->blocked_waitq,
+ fch->max_background - fch->num_background);
+ spin_unlock(&fch->bg_lock);
+}
+
+unsigned int fuse_chan_num_waiting(struct fuse_chan *fch)
+{
+ return atomic_read(&fch->num_waiting);
+}
+
+void fuse_chan_set_fc(struct fuse_chan *fch, struct fuse_conn *fc)
+{
+ fch->conn = fc;
+}
+
+void fuse_pqueue_init(struct fuse_pqueue *fpq)
+{
+ spin_lock_init(&fpq->lock);
+ INIT_LIST_HEAD(&fpq->io);
+ fpq->connected = 1;
+ fpq->processing = NULL;
+}
+
+static struct fuse_dev *fuse_dev_alloc_no_pq(void)
+{
+ struct fuse_dev *fud;
+
+ fud = kzalloc_obj(struct fuse_dev);
+ if (!fud)
+ return NULL;
+
+ refcount_set(&fud->ref, 1);
+ fuse_pqueue_init(&fud->pq);
+
+ return fud;
+}
+
+struct fuse_dev *fuse_dev_alloc(void)
+{
+ struct fuse_dev *fud __free(kfree) = fuse_dev_alloc_no_pq();
+ if (!fud)
+ return NULL;
+
+ fud->pq.processing = fuse_pqueue_alloc();
+ if (!fud->pq.processing)
+ return NULL;
+
+ return no_free_ptr(fud);
+}
+EXPORT_SYMBOL_GPL(fuse_dev_alloc);
+
+/*
+ * Installs @fch into @fud, return true on success. "Consumes" @pq in either case.
+ */
+static bool fuse_dev_install_with_pq(struct fuse_dev *fud, struct fuse_chan *fch,
+ struct list_head *pq)
+{
+ struct fuse_chan *old_fch;
+
+ guard(spinlock)(&fch->lock);
+ /*
+ * Pairs with:
+ * - xchg() in fuse_dev_release()
+ * - smp_load_acquire() in fuse_dev_fc_get()
+ */
+ old_fch = cmpxchg(&fud->chan, NULL, fch);
+ if (old_fch) {
+ /*
+ * failed to set fud->chan because
+ * - it was already set to a different fc
+ * - it was set to disconneted
+ */
+ kfree(pq);
+ return false;
+ }
+ if (pq) {
+ WARN_ON(fud->pq.processing);
+ fud->pq.processing = pq;
+ }
+ list_add_tail(&fud->entry, &fch->devices);
+ fuse_conn_get(fch->conn);
+ wake_up_all(&fuse_dev_waitq);
+ return true;
+}
+
+void fuse_dev_install(struct fuse_dev *fud, struct fuse_chan *fch)
+{
+ struct list_head *pq = fch->pq_prealloc;
+
+ fch->pq_prealloc = NULL;
+ if (!fuse_dev_install_with_pq(fud, fch, pq)) {
+ /* Channel is not usable without a dev */
+ fuse_chan_abort(fch, false);
+ }
+}
+EXPORT_SYMBOL_GPL(fuse_dev_install);
+
+struct fuse_dev *fuse_dev_alloc_install(struct fuse_chan *fch)
+{
+ struct fuse_dev *fud;
+
+ fud = fuse_dev_alloc_no_pq();
+ if (!fud)
+ return NULL;
+
+ fuse_dev_install(fud, fch);
+ return fud;
+}
+EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
+
+void fuse_dev_put(struct fuse_dev *fud)
+{
+ struct fuse_chan *fch;
+
+ if (!refcount_dec_and_test(&fud->ref))
+ return;
+
+ fch = fuse_dev_chan_get(fud);
+ if (fch && fch != FUSE_DEV_CHAN_DISCONNECTED) {
+ /* This is the virtiofs case (fuse_dev_release() not called) */
+ spin_lock(&fch->lock);
+ list_del(&fud->entry);
+ spin_unlock(&fch->lock);
+
+ fuse_conn_put(fch->conn);
+ }
+ kfree(fud->pq.processing);
+ kfree(fud);
+}
+EXPORT_SYMBOL_GPL(fuse_dev_put);
+
+bool fuse_dev_is_installed(struct fuse_dev *fud)
+{
+ struct fuse_chan *fch = fuse_dev_chan_get(fud);
+
+ return fch != NULL && fch != FUSE_DEV_CHAN_DISCONNECTED;
+}
+
+/*
+ * Checks if @fc matches the one installed in @fud
+ */
+bool fuse_dev_verify(struct fuse_dev *fud, struct fuse_chan *fch)
+{
+ return fuse_dev_chan_get(fud) == fch;
+}
+
+bool fuse_dev_is_sync_init(struct fuse_dev *fud)
+{
+ return fud->sync_init;
+}
+
+struct fuse_dev *fuse_dev_grab(struct file *file)
+{
+ struct fuse_dev *fud = fuse_file_to_fud(file);
+
+ refcount_inc(&fud->ref);
+ return fud;
+}
+
+static void fuse_send_one(struct fuse_iqueue *fiq, struct fuse_req *req)
+{
+ req->in.h.len = sizeof(struct fuse_in_header) +
+ fuse_len_args(req->args->in_numargs,
+ (struct fuse_arg *) req->args->in_args);
+ fiq->ops->send_req(fiq, req);
+}
+
+void fuse_chan_queue_forget(struct fuse_chan *fch, struct fuse_forget_link *forget,
+ u64 nodeid, u64 nlookup)
+{
+ struct fuse_iqueue *fiq = &fch->iq;
+
+ forget->forget_one.nodeid = nodeid;
+ forget->forget_one.nlookup = nlookup;
+
+ fiq->ops->send_forget(fiq, forget);
+}
+
+static void flush_bg_queue(struct fuse_chan *fch)
+{
+ struct fuse_iqueue *fiq = &fch->iq;
+
+ while (fch->active_background < fch->max_background &&
+ !list_empty(&fch->bg_queue)) {
+ struct fuse_req *req;
+
+ req = list_first_entry(&fch->bg_queue, struct fuse_req, list);
+ list_del(&req->list);
+ fch->active_background++;
+ fuse_send_one(fiq, req);
+ }
+}
+
+void fuse_request_bg_finish(struct fuse_chan *fch, struct fuse_req *req)
+{
+ lockdep_assert_held(&fch->bg_lock);
+
+ clear_bit(FR_BACKGROUND, &req->flags);
+ if (fch->num_background == fch->max_background) {
+ fch->blocked = 0;
+ wake_up(&fch->blocked_waitq);
+ } else if (!fch->blocked) {
+ /*
+ * Wake up next waiter, if any. It's okay to use
+ * waitqueue_active(), as we've already synced up
+ * fch->blocked with waiters with the wake_up() call
+ * above.
+ */
+ if (waitqueue_active(&fch->blocked_waitq))
+ wake_up(&fch->blocked_waitq);
+ }
+
+ fch->num_background--;
+ fch->active_background--;
+}
+
+/*
+ * 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_chan *fch = req->chan;
+ struct fuse_iqueue *fiq = &fch->iq;
+
+ if (test_and_set_bit(FR_FINISHED, &req->flags))
+ goto put_request;
+
+ trace_fuse_request_end(req);
+ /*
+ * test_and_set_bit() implies smp_mb() between bit
+ * changing and below FR_INTERRUPTED check. Pairs with
+ * smp_mb() from queue_interrupt().
+ */
+ if (test_bit(FR_INTERRUPTED, &req->flags)) {
+ spin_lock(&fiq->lock);
+ list_del_init(&req->intr_entry);
+ spin_unlock(&fiq->lock);
+ }
+ WARN_ON(test_bit(FR_PENDING, &req->flags));
+ WARN_ON(test_bit(FR_SENT, &req->flags));
+ if (test_bit(FR_BACKGROUND, &req->flags)) {
+ spin_lock(&fch->bg_lock);
+ fuse_request_bg_finish(fch, req);
+ flush_bg_queue(fch);
+ spin_unlock(&fch->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(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->chan->iq;
+
+ /* Check for we've sent request to interrupt this req */
+ if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags)))
+ return -EINVAL;
+
+ fiq->ops->send_interrupt(fiq, req);
+
+ return 0;
+}
+
+bool fuse_remove_pending_req(struct fuse_req *req, spinlock_t *lock)
+{
+ spin_lock(lock);
+ if (test_bit(FR_PENDING, &req->flags)) {
+ /*
+ * FR_PENDING does not get cleared as the request will end
+ * up in destruction anyway.
+ */
+ list_del(&req->list);
+ spin_unlock(lock);
+ __fuse_put_request(req);
+ req->out.h.error = -EINTR;
+ return true;
+ }
+ spin_unlock(lock);
+ return false;
+}
+
+static void request_wait_answer(struct fuse_req *req)
+{
+ struct fuse_chan *fch = req->chan;
+ struct fuse_iqueue *fiq = &fch->iq;
+ int err;
+
+ if (!fch->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)) {
+ bool removed;
+
+ /* Only fatal signals may interrupt this */
+ err = wait_event_killable(req->waitq,
+ test_bit(FR_FINISHED, &req->flags));
+ if (!err)
+ return;
+
+ if (req->args->abort_on_kill) {
+ fuse_chan_abort(fch, false);
+ goto wait_for_finish;
+ }
+
+ if (test_bit(FR_URING, &req->flags))
+ removed = fuse_uring_remove_pending_req(req);
+ else
+ removed = fuse_remove_pending_req(req, &fiq->lock);
+ if (removed)
+ return;
+ }
+
+wait_for_finish:
+ /*
+ * 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->chan->iq;
+
+ BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
+
+ /* acquire extra reference, since request is still needed after
+ fuse_request_end() */
+ __fuse_get_request(req);
+ /*
+ * This is a synchronous request: the caller will block waiting for
+ * the answer. Hint the scheduler via wake_up_sync().
+ */
+ set_bit(FR_SYNC_WAKEUP, &req->flags);
+ fuse_send_one(fiq, req);
+
+ request_wait_answer(req);
+ /* Pairs with smp_wmb() in fuse_request_end() */
+ smp_rmb();
+}
+
+static void fuse_adjust_compat(struct fuse_chan *fch, struct fuse_args *args)
+{
+ if (fch->minor < 4 && args->opcode == FUSE_STATFS)
+ args->out_args[0].size = FUSE_COMPAT_STATFS_SIZE;
+
+ if (fch->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 (fch->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_args_to_req(struct fuse_req *req, struct fuse_args *args)
+{
+ req->in.h.opcode = args->opcode;
+ req->in.h.nodeid = args->nodeid;
+ req->in.h.uid = args->uid;
+ req->in.h.gid = args->gid;
+ req->in.h.pid = args->pid;
+ req->args = args;
+ if (args->is_ext)
+ req->in.h.total_extlen = args->in_args[args->ext_idx].size / 8;
+ if (args->end)
+ __set_bit(FR_ASYNC, &req->flags);
+}
+
+ssize_t fuse_chan_send(struct fuse_chan *fch, struct fuse_args *args)
+{
+ struct fuse_req *req;
+ ssize_t ret;
+
+ if (args->force) {
+ atomic_inc(&fch->num_waiting);
+ req = fuse_request_alloc(fch, GFP_KERNEL | __GFP_NOFAIL);
+
+ __set_bit(FR_WAITING, &req->flags);
+ if (!args->abort_on_kill)
+ __set_bit(FR_FORCE, &req->flags);
+ } else {
+ req = fuse_get_req(fch, false);
+ if (IS_ERR(req))
+ return PTR_ERR(req);
+ }
+
+ /* Needs to be done after fuse_get_req() so that fch->minor is valid */
+ fuse_adjust_compat(fch, 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;
+}
+
+#ifdef CONFIG_FUSE_IO_URING
+static bool fuse_request_queue_background_uring(struct fuse_req *req)
+{
+ struct fuse_iqueue *fiq = &req->chan->iq;
+
+ req->in.h.len = sizeof(struct fuse_in_header) +
+ fuse_len_args(req->args->in_numargs,
+ (struct fuse_arg *) req->args->in_args);
+ fuse_request_assign_unique(fiq, req);
+
+ return fuse_uring_queue_bq_req(req);
+}
+#endif
+
+/*
+ * @return true if queued
+ */
+static int fuse_request_queue_background(struct fuse_req *req)
+{
+ struct fuse_chan *fch = req->chan;
+ 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(&fch->num_waiting);
+ }
+ __set_bit(FR_ISREPLY, &req->flags);
+
+#ifdef CONFIG_FUSE_IO_URING
+ if (fuse_uring_ready(fch))
+ return fuse_request_queue_background_uring(req);
+#endif
+
+ spin_lock(&fch->bg_lock);
+ if (likely(fch->connected)) {
+ fch->num_background++;
+ if (fch->num_background == fch->max_background)
+ fch->blocked = 1;
+ list_add_tail(&req->list, &fch->bg_queue);
+ flush_bg_queue(fch);
+ queued = true;
+ }
+ spin_unlock(&fch->bg_lock);
+
+ return queued;
+}
+
+int fuse_chan_send_bg(struct fuse_chan *fch, struct fuse_args *args, gfp_t gfp_flags)
+{
+ struct fuse_req *req;
+
+ if (args->force) {
+ req = fuse_request_alloc(fch, gfp_flags);
+ if (!req)
+ return -ENOMEM;
+ __set_bit(FR_BACKGROUND, &req->flags);
+ } else {
+ req = fuse_get_req(fch, 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;
+}
+
+int fuse_chan_send_notify_reply(struct fuse_chan *fch, struct fuse_args *args, u64 unique)
+{
+ struct fuse_req *req;
+ struct fuse_iqueue *fiq = &fch->iq;
+
+ req = fuse_get_req(fch, 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);
+
+ fuse_send_one(fiq, req);
+
+ return 0;
+}
+
+/*
+ * 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;
+}
+
+void fuse_copy_init(struct fuse_copy_state *cs, bool write,
+ struct iov_iter *iter)
+{
+ memset(cs, 0, sizeof(*cs));
+ cs->write = write;
+ cs->iter = iter;
+}
+
+/* Unmap and put previous page of userspace buffer */
+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_pages2(cs->iter, &page, PAGE_SIZE, 1, &off);
+ if (err < 0)
+ return err;
+ BUG_ON(!err);
+ cs->len = err;
+ cs->offset = off;
+ cs->pg = page;
+ }
+
+ 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_local_page(cs->pg);
+ void *buf = pgaddr + cs->offset;
+
+ if (cs->write)
+ memcpy(buf, *val, ncpy);
+ else
+ memcpy(*val, buf, ncpy);
+
+ kunmap_local(pgaddr);
+ *val += ncpy;
+ }
+ *size -= ncpy;
+ cs->len -= ncpy;
+ cs->offset += ncpy;
+ if (cs->is_uring)
+ cs->ring.copied_sz += ncpy;
+
+ return ncpy;
+}
+
+static int fuse_check_folio(struct folio *folio)
+{
+ if (folio_mapped(folio) ||
+ folio->mapping != NULL ||
+ (folio->flags.f & PAGE_FLAGS_CHECK_AT_PREP &
+ ~(1 << PG_locked |
+ 1 << PG_referenced |
+ 1 << PG_lru |
+ 1 << PG_active |
+ 1 << PG_workingset |
+ 1 << PG_reclaim |
+ 1 << PG_waiters |
+ LRU_GEN_MASK | LRU_REFS_MASK))) {
+ dump_page(&folio->page, "fuse: trying to steal weird page");
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * Attempt to steal a page from the splice() pipe and move it into the
+ * pagecache. If successful, the pointer in @pagep will be updated. The
+ * folio that was originally in @pagep will lose a reference and the new
+ * folio returned in @pagep will carry a reference.
+ */
+static int fuse_try_move_folio(struct fuse_copy_state *cs, struct folio **foliop)
+{
+ int err;
+ struct folio *oldfolio = *foliop;
+ struct folio *newfolio;
+ struct pipe_buffer *buf = cs->pipebufs;
+
+ folio_get(oldfolio);
+ 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 != folio_size(oldfolio))
+ goto out_fallback;
+
+ if (!pipe_buf_try_steal(cs->pipe, buf))
+ goto out_fallback;
+
+ newfolio = page_folio(buf->page);
+
+ folio_clear_uptodate(newfolio);
+ folio_clear_mappedtodisk(newfolio);
+
+ if (folio_test_large(newfolio))
+ goto out_fallback_unlock;
+
+ if (fuse_check_folio(newfolio) != 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(folio_mapped(oldfolio)))
+ goto out_fallback_unlock;
+ if (WARN_ON(folio_has_private(oldfolio)))
+ goto out_fallback_unlock;
+ if (WARN_ON(folio_test_dirty(oldfolio) ||
+ folio_test_writeback(oldfolio)))
+ goto out_fallback_unlock;
+ if (WARN_ON(folio_test_mlocked(oldfolio)))
+ goto out_fallback_unlock;
+
+ err = lock_request(cs->req);
+ if (err)
+ goto out_fallback_unlock;
+
+ replace_page_cache_folio(oldfolio, newfolio);
+
+ folio_get(newfolio);
+
+ if (!(buf->flags & PIPE_BUF_FLAG_LRU))
+ folio_add_lru(newfolio);
+
+ /*
+ * Release while we have extra ref on stolen page. Otherwise
+ * anon_pipe_buf_release() might think the page can be reused.
+ */
+ pipe_buf_release(cs->pipe, buf);
+
+ *foliop = newfolio;
+ folio_unlock(oldfolio);
+ /* Drop ref for ap->pages[] array */
+ folio_put(oldfolio);
+ cs->len = 0;
+
+ err = 0;
+out_put_old:
+ /* Drop ref obtained in this function */
+ folio_put(oldfolio);
+ return err;
+
+out_fallback_unlock:
+ folio_unlock(newfolio);
+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_folio(struct fuse_copy_state *cs, struct folio *folio,
+ unsigned offset, unsigned count)
+{
+ struct pipe_buffer *buf;
+ int err;
+
+ if (cs->nr_segs >= cs->pipe->max_usage)
+ return -EIO;
+
+ folio_get(folio);
+ err = unlock_request(cs->req);
+ if (err) {
+ folio_put(folio);
+ return err;
+ }
+
+ fuse_copy_finish(cs);
+
+ buf = cs->pipebufs;
+ buf->page = &folio->page;
+ buf->offset = offset;
+ buf->len = count;
+
+ cs->pipebufs++;
+ cs->nr_segs++;
+ cs->len = 0;
+
+ return lock_request(cs->req);
+}
+
+/*
+ * Copy a folio in the request to/from the userspace buffer. Must be
+ * done atomically
+ */
+int fuse_copy_folio(struct fuse_copy_state *cs, struct folio **foliop,
+ unsigned offset, unsigned count, int zeroing)
+{
+ int err;
+ struct folio *folio = *foliop;
+ size_t size;
+
+ if (folio) {
+ size = folio_size(folio);
+ if (zeroing && count < size) {
+ /*
+ * When the copy is skipped the folio already holds the
+ * payload, so only the bytes outside [offset, offset +
+ * count) may be zeroed.
+ *
+ * Otherwise, the whole folio is cleared first so that a
+ * failed copy leaves zeros rather than stale folio
+ * contents.
+ */
+ if (cs->skip_folio_copy)
+ folio_zero_segments(folio, 0, offset,
+ offset + count, size);
+ else
+ folio_zero_range(folio, 0, size);
+ }
+ }
+
+ while (!cs->skip_folio_copy && count) {
+ if (cs->write && cs->pipebufs && folio) {
+ /*
+ * Can't control lifetime of pipe buffers, so always
+ * copy user pages.
+ */
+ if (cs->req->args->user_pages) {
+ err = fuse_copy_fill(cs);
+ if (err)
+ return err;
+ } else {
+ return fuse_ref_folio(cs, folio, offset, count);
+ }
+ } else if (!cs->len) {
+ if (cs->move_folios && folio &&
+ offset == 0 && count == size) {
+ err = fuse_try_move_folio(cs, foliop);
+ if (err <= 0)
+ return err;
+ } else {
+ err = fuse_copy_fill(cs);
+ if (err)
+ return err;
+ }
+ }
+ if (folio) {
+ void *mapaddr = kmap_local_folio(folio, offset);
+ void *buf = mapaddr;
+ unsigned int copy = count;
+ unsigned int bytes_copied;
+
+ if (folio_test_highmem(folio) && count > PAGE_SIZE - offset_in_page(offset))
+ copy = PAGE_SIZE - offset_in_page(offset);
+
+ bytes_copied = fuse_copy_do(cs, &buf, &copy);
+ kunmap_local(mapaddr);
+ offset += bytes_copied;
+ count -= bytes_copied;
+ } else
+ offset += fuse_copy_do(cs, NULL, &count);
+ }
+ if (folio && !cs->write)
+ flush_dcache_folio(folio);
+ return 0;
+}
+
+/* Copy folios in the request to/from userspace buffer */
+static int fuse_copy_folios(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_folios && (nbytes || zeroing); i++) {
+ int err;
+ unsigned int offset = ap->descs[i].offset;
+ unsigned int count = min(nbytes, ap->descs[i].length);
+
+ err = fuse_copy_folio(cs, &ap->folios[i], offset, count, zeroing);
+ if (err)
+ return err;
+
+ nbytes -= count;
+ }
+ return 0;
+}
+
+/* Copy a single argument in the request to/from userspace buffer */
+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 */
+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)
+ /*
+ * if cs->skip_folio_copy is set, this just does any
+ * needed zeroing. No copying is involved.
+ */
+ err = fuse_copy_folios(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)
+__releases(fiq->lock)
+{
+ struct fuse_req *req = list_first_entry(&fiq->interrupts, struct fuse_req, intr_entry);
+ struct fuse_interrupt_in arg = {
+ .unique = req->in.h.unique,
+ };
+ struct fuse_in_header ih = {
+ .opcode = FUSE_INTERRUPT,
+ .unique = (req->in.h.unique | FUSE_INT_REQ_BIT),
+ .len = sizeof(ih) + sizeof(arg),
+ };
+ int err;
+
+ list_del_init(&req->intr_entry);
+ spin_unlock(&fiq->lock);
+
+ 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 : ih.len;
+}
+
+static 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;
+}
+
+static int fuse_read_single_forget(struct fuse_iqueue *fiq,
+ struct fuse_copy_state *cs)
+__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_locked(fiq),
+ .len = sizeof(ih) + sizeof(arg),
+ };
+
+ spin_unlock(&fiq->lock);
+ kfree(forget);
+
+ 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_locked(fiq),
+ .len = sizeof(ih) + sizeof(arg),
+ };
+
+ 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_chan *fch, struct fuse_iqueue *fiq,
+ struct fuse_copy_state *cs,
+ size_t nbytes)
+__releases(fiq->lock)
+{
+ if (fch->minor < 16 || fiq->forget_list_head.next->next == NULL)
+ return fuse_read_single_forget(fiq, cs);
+ 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_chan *fch = fud->chan;
+ struct fuse_iqueue *fiq = &fch->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) +
+ fch->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 = fch->abort_with_err ? -ECONNABORTED : -ENODEV;
+ goto err_unlock;
+ }
+
+ if (!list_empty(&fiq->interrupts))
+ return fuse_read_interrupt(fiq, cs);
+
+ if (forget_pending(fiq)) {
+ if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
+ return fuse_read_forget(fch, 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);
+ /*
+ * Must not put request on fpq->io queue after having been shut down by
+ * fuse_chan_abort()
+ */
+ if (!fpq->connected) {
+ req->out.h.error = err = -ECONNABORTED;
+ goto out_end;
+ }
+ list_add(&req->list, &fpq->io);
+ spin_unlock(&fpq->lock);
+ cs->req = req;
+ err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h));
+ if (!err)
+ err = fuse_copy_args(cs, args->in_numargs, args->in_pages,
+ (struct fuse_arg *) args->in_args, 0);
+ fuse_copy_finish(cs);
+ spin_lock(&fpq->lock);
+ clear_bit(FR_LOCKED, &req->flags);
+ if (!fpq->connected) {
+ err = fch->abort_with_err ? -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);
+ trace_fuse_request_sent(req);
+ 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)
+{
+ struct fuse_dev *fud = fuse_dev_alloc_no_pq();
+
+ if (!fud)
+ return -ENOMEM;
+
+ file->private_data = fud;
+ return 0;
+}
+
+struct fuse_dev *fuse_get_dev(struct file *file)
+{
+ struct fuse_dev *fud = fuse_file_to_fud(file);
+ int err;
+
+ if (unlikely(!fuse_dev_chan_get(fud))) {
+ /* only block waiting for mount if sync init was requested */
+ if (!fud->sync_init)
+ return ERR_PTR(-EPERM);
+
+ err = wait_event_interruptible(fuse_dev_waitq, fuse_dev_chan_get(fud) != NULL);
+ if (err)
+ return ERR_PTR(err);
+ }
+
+ return fud;
+}
+
+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 (IS_ERR(fud))
+ return PTR_ERR(fud);
+
+ if (!user_backed_iter(to))
+ return -EINVAL;
+
+ fuse_copy_init(&cs, true, 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 (IS_ERR(fud))
+ return PTR_ERR(fud);
+
+ bufs = kvmalloc_objs(struct pipe_buffer, pipe->max_usage);
+ if (!bufs)
+ return -ENOMEM;
+
+ fuse_copy_init(&cs, true, NULL);
+ cs.pipebufs = bufs;
+ cs.pipe = pipe;
+ ret = fuse_dev_do_read(fud, in, &cs, len);
+ if (ret < 0)
+ goto out;
+
+ if (pipe_buf_usage(pipe) + 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;
+}
+
+/*
+ * Resending all processing queue requests.
+ *
+ * During a FUSE daemon panics and failover, it is possible for some inflight
+ * requests to be lost and never returned. As a result, applications awaiting
+ * replies would become stuck forever. To address this, we can use notification
+ * to trigger resending of these pending requests to the FUSE daemon, ensuring
+ * they are properly processed again.
+ *
+ * Please note that this strategy is applicable only to idempotent requests or
+ * if the FUSE daemon takes careful measures to avoid processing duplicated
+ * non-idempotent requests.
+ */
+void fuse_chan_resend(struct fuse_chan *fch)
+{
+ struct fuse_dev *fud;
+ struct fuse_req *req;
+ struct fuse_iqueue *fiq = &fch->iq;
+ LIST_HEAD(to_queue);
+ unsigned int i;
+
+ spin_lock(&fch->lock);
+ if (!fch->connected) {
+ spin_unlock(&fch->lock);
+ return;
+ }
+
+ list_for_each_entry(fud, &fch->devices, entry) {
+ struct fuse_pqueue *fpq = &fud->pq;
+
+ spin_lock(&fpq->lock);
+ for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) {
+ struct list_head *this_queue = &fpq->processing[i];
+
+ list_for_each_entry(req, this_queue, list)
+ clear_bit(FR_SENT, &req->flags);
+ list_splice_tail_init(this_queue, &to_queue);
+ }
+ spin_unlock(&fpq->lock);
+ }
+ spin_unlock(&fch->lock);
+
+ spin_lock(&fiq->lock);
+ if (!fiq->connected) {
+ spin_unlock(&fiq->lock);
+ fuse_dev_end_requests(&to_queue);
+ return;
+ }
+ /*
+ * Remove interrupt entries for resent requests to prevent stale
+ * intr_entry on fiq->interrupts after the request is re-queued.
+ */
+ list_for_each_entry(req, &to_queue, list) {
+ set_bit(FR_PENDING, &req->flags);
+ /* mark the request as resend request */
+ req->in.h.unique |= FUSE_UNIQUE_RESEND;
+
+ if (test_bit(FR_INTERRUPTED, &req->flags))
+ list_del_init(&req->intr_entry);
+ }
+ /* iq and pq requests are both oldest to newest */
+ list_splice(&to_queue, &fiq->pending);
+ fuse_dev_wake_and_unlock(fiq, false);
+}
+
+/* Look up request on processing list by unique ID */
+struct fuse_req *fuse_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;
+}
+
+int fuse_copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
+ unsigned nbytes)
+{
+
+ unsigned int reqsize = 0;
+
+ /*
+ * Uring has all headers separated from args - args is payload only
+ */
+ if (!cs->is_uring)
+ 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_chan *fch = fud->chan;
+ 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) {
+ /*
+ * Only allow notifications during while the connection is in an
+ * initialized and connected state
+ */
+ err = -EINVAL;
+ /* Pairs with smp_store_release() in fuse_chan_set_initialized() */
+ if (!smp_load_acquire(&fch->initialized) || !fch->connected)
+ goto copy_finish;
+
+ /* Don't try to move folios (yet) */
+ cs->move_folios = false;
+
+ err = fuse_notify(fch->conn, oh.error, nbytes - sizeof(oh), cs);
+ goto copy_finish;
+ }
+
+ err = -EINVAL;
+ if (oh.error <= -512 || oh.error > 0)
+ goto copy_finish;
+
+ spin_lock(&fpq->lock);
+ req = NULL;
+ if (fpq->connected)
+ req = fuse_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)
+ fch->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_folios = false;
+
+ if (oh.error)
+ err = nbytes != sizeof(oh) ? -EINVAL : 0;
+ else
+ err = fuse_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 (!user_backed_iter(from))
+ return -EINVAL;
+
+ fuse_copy_init(&cs, false, 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, count;
+ unsigned nbuf;
+ unsigned idx;
+ struct pipe_buffer *bufs;
+ struct fuse_copy_state cs;
+ struct fuse_dev *fud = __fuse_get_dev(out);
+ size_t rem;
+ ssize_t ret;
+
+ if (!fud)
+ return -EPERM;
+
+ pipe_lock(pipe);
+
+ head = pipe->head;
+ tail = pipe->tail;
+ count = pipe_occupancy(head, tail);
+
+ bufs = kvmalloc_objs(struct pipe_buffer, count);
+ if (!bufs) {
+ pipe_unlock(pipe);
+ return -ENOMEM;
+ }
+
+ nbuf = 0;
+ rem = 0;
+ for (idx = tail; !pipe_empty(head, idx) && rem < len; idx++)
+ rem += pipe_buf(pipe, idx)->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 || pipe_empty(head, tail)))
+ goto out_free;
+
+ ibuf = pipe_buf(pipe, tail);
+ 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, false, NULL);
+ cs.pipebufs = bufs;
+ cs.nr_segs = nbuf;
+ cs.pipe = pipe;
+
+ if (flags & SPLICE_F_MOVE)
+ cs.move_folios = true;
+
+ ret = fuse_dev_do_write(fud, &cs, len);
+
+ pipe_lock(pipe);
+out_free:
+ for (idx = 0; idx < nbuf; idx++) {
+ struct pipe_buffer *buf = &bufs[idx];
+
+ if (buf->ops)
+ pipe_buf_release(pipe, buf);
+ }
+ pipe_unlock(pipe);
+
+ kvfree(bufs);
+ return ret;
+}
+
+static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
+{
+ __poll_t mask = EPOLLOUT | EPOLLWRNORM;
+ struct fuse_iqueue *fiq;
+ struct fuse_dev *fud = fuse_get_dev(file);
+
+ if (IS_ERR(fud))
+ return EPOLLERR;
+
+ fiq = &fud->chan->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) */
+void fuse_dev_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);
+ }
+}
+
+/*
+ * 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/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_chan_abort(struct fuse_chan *fch, bool abort_with_err)
+{
+ struct fuse_iqueue *fiq = &fch->iq;
+
+ fch->abort_with_err = abort_with_err;
+
+ spin_lock(&fch->lock);
+ if (fch->connected) {
+ struct fuse_dev *fud;
+ struct fuse_req *req, *next;
+ LIST_HEAD(to_end);
+ unsigned int i;
+
+ if (fch->timeout.req_timeout)
+ cancel_delayed_work(&fch->timeout.work);
+
+ /* Background queuing checks fch->connected under bg_lock */
+ spin_lock(&fch->bg_lock);
+ fch->connected = 0;
+ spin_unlock(&fch->bg_lock);
+
+ fuse_chan_set_initialized(fch, NULL);
+ list_for_each_entry(fud, &fch->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(&fch->bg_lock);
+ fch->blocked = 0;
+ fch->max_background = UINT_MAX;
+ flush_bg_queue(fch);
+ spin_unlock(&fch->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);
+ fuse_end_polls(fch->conn);
+ wake_up_all(&fch->blocked_waitq);
+ spin_unlock(&fch->lock);
+
+ fuse_dev_end_requests(&to_end);
+
+ /*
+ * fch->lock must not be taken to avoid conflicts with io-uring
+ * locks
+ */
+ fuse_uring_abort(fch);
+ } else {
+ spin_unlock(&fch->lock);
+ }
+}
+EXPORT_SYMBOL_GPL(fuse_chan_abort);
+
+void fuse_chan_wait_aborted(struct fuse_chan *fch)
+{
+ /* matches implicit memory barrier in fuse_drop_waiting() */
+ smp_mb();
+ wait_event(fch->blocked_waitq, fuse_chan_num_waiting(fch) == 0);
+
+ fuse_uring_wait_stopped_queues(fch);
+}
+
+int fuse_dev_release(struct inode *inode, struct file *file)
+{
+ struct fuse_dev *fud = fuse_file_to_fud(file);
+ /* Pairs with cmpxchg() in fuse_dev_install() */
+ struct fuse_chan *fch = xchg(&fud->chan, FUSE_DEV_CHAN_DISCONNECTED);
+
+ if (fch) {
+ struct fuse_pqueue *fpq = &fud->pq;
+ LIST_HEAD(to_end);
+ unsigned int i;
+ bool last;
+
+ /* Make sure fuse_dev_install_with_pq() has finished */
+ spin_lock(&fch->lock);
+ 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);
+
+ list_del(&fud->entry);
+ /* Are we the last open device? */
+ last = list_empty(&fch->devices);
+ spin_unlock(&fch->lock);
+
+ fuse_dev_end_requests(&to_end);
+
+ if (last) {
+ WARN_ON(fch->iq.fasync != NULL);
+ fuse_chan_abort(fch, false);
+ }
+ fuse_conn_put(fch->conn);
+ }
+ fuse_dev_put(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 (IS_ERR(fud))
+ return PTR_ERR(fud);
+
+ /* No locking - fasync_helper does its own locking */
+ return fasync_helper(fd, file, on, &fud->chan->iq.fasync);
+}
+
+static long fuse_dev_ioctl_clone(struct file *file, __u32 __user *argp)
+{
+ int oldfd;
+ struct fuse_dev *fud, *new_fud;
+ struct list_head *pq;
+
+ if (get_user(oldfd, argp))
+ return -EFAULT;
+
+ CLASS(fd, f)(oldfd);
+ if (fd_empty(f))
+ return -EINVAL;
+
+ /*
+ * Check against file->f_op because CUSE
+ * uses the same ioctl handler.
+ */
+ if (fd_file(f)->f_op != file->f_op)
+ return -EINVAL;
+
+ fud = fuse_get_dev(fd_file(f));
+ if (IS_ERR(fud))
+ return PTR_ERR(fud);
+
+ pq = fuse_pqueue_alloc();
+ if (!pq)
+ return -ENOMEM;
+
+ new_fud = fuse_file_to_fud(file);
+ if (!fuse_dev_install_with_pq(new_fud, fud->chan, pq))
+ return -EINVAL;
+
+ return 0;
+}
+
+static long fuse_dev_ioctl_backing_open(struct file *file,
+ struct fuse_backing_map __user *argp)
+{
+ struct fuse_dev *fud = fuse_get_dev(file);
+ struct fuse_backing_map map;
+
+ if (IS_ERR(fud))
+ return PTR_ERR(fud);
+
+ if (!IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
+ return -EOPNOTSUPP;
+
+ if (copy_from_user(&map, argp, sizeof(map)))
+ return -EFAULT;
+
+ return fuse_backing_open(fud->chan->conn, &map);
+}
+
+static long fuse_dev_ioctl_backing_close(struct file *file, __u32 __user *argp)
+{
+ struct fuse_dev *fud = fuse_get_dev(file);
+ int backing_id;
+
+ if (IS_ERR(fud))
+ return PTR_ERR(fud);
+
+ if (!IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
+ return -EOPNOTSUPP;
+
+ if (get_user(backing_id, argp))
+ return -EFAULT;
+
+ return fuse_backing_close(fud->chan->conn, backing_id);
+}
+
+static long fuse_dev_ioctl_sync_init(struct file *file)
+{
+ struct fuse_dev *fud = fuse_file_to_fud(file);
+
+ if (fuse_dev_chan_get(fud))
+ return -EINVAL;
+
+ fud->sync_init = true;
+ return 0;
+}
+
+static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+
+ switch (cmd) {
+ case FUSE_DEV_IOC_CLONE:
+ return fuse_dev_ioctl_clone(file, argp);
+
+ case FUSE_DEV_IOC_BACKING_OPEN:
+ return fuse_dev_ioctl_backing_open(file, argp);
+
+ case FUSE_DEV_IOC_BACKING_CLOSE:
+ return fuse_dev_ioctl_backing_close(file, argp);
+
+ case FUSE_DEV_IOC_SYNC_INIT:
+ return fuse_dev_ioctl_sync_init(file);
+
+ default:
+ return -ENOTTY;
+ }
+}
+
+#ifdef CONFIG_PROC_FS
+static void fuse_dev_show_fdinfo(struct seq_file *seq, struct file *file)
+{
+ struct fuse_dev *fud = __fuse_get_dev(file);
+ if (!fud)
+ return;
+
+ seq_printf(seq, "fuse_connection:\t%u\n", fuse_conn_get_id(fud->chan->conn));
+}
+#endif
+
+const struct file_operations fuse_dev_operations = {
+ .owner = THIS_MODULE,
+ .open = fuse_dev_open,
+ .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,
+#ifdef CONFIG_FUSE_IO_URING
+ .uring_cmd = fuse_uring_cmd,
+#endif
+#ifdef CONFIG_PROC_FS
+ .show_fdinfo = fuse_dev_show_fdinfo,
+#endif
+};
+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);
+}
generated by cgit v1.3.1 (git 2.54.0) at 2026-10-10 10:26:36 +0000