summaryrefslogtreecommitdiffstats
path: root/fs/fuse/dev.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/fuse/dev.c')
-rw-r--r--fs/fuse/dev.c2755
1 files changed, 2755 insertions, 0 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
new file mode 100644
index 000000000..5dda7080f
--- /dev/null
+++ b/fs/fuse/dev.c
@@ -0,0 +1,2755 @@
+/*
+ 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 "dev_uring_i.h"
+#include "fuse_i.h"
+#include "fuse_dev_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 struct kmem_cache *fuse_req_cachep;
+
+const unsigned long fuse_timeout_timer_freq =
+ secs_to_jiffies(FUSE_TIMEOUT_TIMER_FREQ);
+
+bool fuse_request_expired(struct fuse_conn *fc, struct list_head *list)
+{
+ struct fuse_req *req;
+
+ req = list_first_entry_or_null(list, struct fuse_req, list);
+ if (!req)
+ return false;
+ return time_is_before_jiffies(req->create_time + fc->timeout.req_timeout);
+}
+
+static bool fuse_fpq_processing_expired(struct fuse_conn *fc, struct list_head *processing)
+{
+ int i;
+
+ for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
+ if (fuse_request_expired(fc, &processing[i]))
+ return true;
+
+ return false;
+}
+
+/*
+ * Check if any requests aren't being completed by the time the request timeout
+ * elapses. To do so, we:
+ * - check the fiq pending list
+ * - check the bg queue
+ * - check the fpq io and processing lists
+ *
+ * To make this fast, we only check against the head request on each list since
+ * these are generally queued in order of creation time (eg newer requests get
+ * queued to the tail). We might miss a few edge cases (eg requests transitioning
+ * between lists, re-sent requests at the head of the pending list having a
+ * later creation time than other requests on that list, etc.) but that is fine
+ * since if the request never gets fulfilled, it will eventually be caught.
+ */
+void fuse_check_timeout(struct work_struct *work)
+{
+ struct delayed_work *dwork = to_delayed_work(work);
+ struct fuse_conn *fc = container_of(dwork, struct fuse_conn,
+ timeout.work);
+ struct fuse_iqueue *fiq = &fc->iq;
+ struct fuse_dev *fud;
+ struct fuse_pqueue *fpq;
+ bool expired = false;
+
+ if (!atomic_read(&fc->num_waiting))
+ goto out;
+
+ spin_lock(&fiq->lock);
+ expired = fuse_request_expired(fc, &fiq->pending);
+ spin_unlock(&fiq->lock);
+ if (expired)
+ goto abort_conn;
+
+ spin_lock(&fc->bg_lock);
+ expired = fuse_request_expired(fc, &fc->bg_queue);
+ spin_unlock(&fc->bg_lock);
+ if (expired)
+ goto abort_conn;
+
+ spin_lock(&fc->lock);
+ if (!fc->connected) {
+ spin_unlock(&fc->lock);
+ return;
+ }
+ list_for_each_entry(fud, &fc->devices, entry) {
+ fpq = &fud->pq;
+ spin_lock(&fpq->lock);
+ if (fuse_request_expired(fc, &fpq->io) ||
+ fuse_fpq_processing_expired(fc, fpq->processing)) {
+ spin_unlock(&fpq->lock);
+ spin_unlock(&fc->lock);
+ goto abort_conn;
+ }
+
+ spin_unlock(&fpq->lock);
+ }
+ spin_unlock(&fc->lock);
+
+ if (fuse_uring_request_expired(fc))
+ goto abort_conn;
+
+out:
+ queue_delayed_work(system_percpu_wq, &fc->timeout.work,
+ fuse_timeout_timer_freq);
+ return;
+
+abort_conn:
+ fuse_abort_conn(fc);
+}
+
+static void fuse_request_init(struct fuse_mount *fm, struct fuse_req *req)
+{
+ INIT_LIST_HEAD(&req->list);
+ INIT_LIST_HEAD(&req->intr_entry);
+ init_waitqueue_head(&req->waitq);
+ refcount_set(&req->count, 1);
+ __set_bit(FR_PENDING, &req->flags);
+ req->fm = fm;
+ req->create_time = jiffies;
+}
+
+static struct fuse_req *fuse_request_alloc(struct fuse_mount *fm, gfp_t flags)
+{
+ struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags);
+ if (req)
+ fuse_request_init(fm, req);
+
+ return req;
+}
+
+static void fuse_request_free(struct fuse_req *req)
+{
+ kmem_cache_free(fuse_req_cachep, req);
+}
+
+static void __fuse_get_request(struct fuse_req *req)
+{
+ refcount_inc(&req->count);
+}
+
+/* Must be called with > 1 refcount */
+static void __fuse_put_request(struct fuse_req *req)
+{
+ refcount_dec(&req->count);
+}
+
+void fuse_set_initialized(struct fuse_conn *fc)
+{
+ /* Make sure stores before this are seen on another CPU */
+ smp_wmb();
+ fc->initialized = 1;
+}
+
+static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
+{
+ return !fc->initialized || (for_background && fc->blocked) ||
+ (fc->io_uring && fc->connected && !fuse_uring_ready(fc));
+}
+
+static void fuse_drop_waiting(struct fuse_conn *fc)
+{
+ /*
+ * lockess check of fc->connected is okay, because atomic_dec_and_test()
+ * provides a memory barrier matched with the one in fuse_wait_aborted()
+ * to ensure no wake-up is missed.
+ */
+ if (atomic_dec_and_test(&fc->num_waiting) &&
+ !READ_ONCE(fc->connected)) {
+ /* wake up aborters */
+ wake_up_all(&fc->blocked_waitq);
+ }
+}
+
+static void fuse_put_request(struct fuse_req *req);
+
+static struct fuse_req *fuse_get_req(struct mnt_idmap *idmap,
+ struct fuse_mount *fm,
+ bool for_background)
+{
+ struct fuse_conn *fc = fm->fc;
+ struct fuse_req *req;
+ bool no_idmap = !fm->sb || (fm->sb->s_iflags & SB_I_NOIDMAP);
+ kuid_t fsuid;
+ kgid_t fsgid;
+ int err;
+
+ atomic_inc(&fc->num_waiting);
+
+ if (fuse_block_alloc(fc, for_background)) {
+ err = -EINTR;
+ if (wait_event_state_exclusive(fc->blocked_waitq,
+ !fuse_block_alloc(fc, for_background),
+ (TASK_KILLABLE | TASK_FREEZABLE)))
+ goto out;
+ }
+ /* Matches smp_wmb() in fuse_set_initialized() */
+ smp_rmb();
+
+ err = -ENOTCONN;
+ if (!fc->connected)
+ goto out;
+
+ err = -ECONNREFUSED;
+ if (fc->conn_error)
+ goto out;
+
+ req = fuse_request_alloc(fm, GFP_KERNEL);
+ err = -ENOMEM;
+ if (!req) {
+ if (for_background)
+ wake_up(&fc->blocked_waitq);
+ goto out;
+ }
+
+ req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
+
+ __set_bit(FR_WAITING, &req->flags);
+ if (for_background)
+ __set_bit(FR_BACKGROUND, &req->flags);
+
+ /*
+ * Keep the old behavior when idmappings support was not
+ * declared by a FUSE server.
+ *
+ * For those FUSE servers who support idmapped mounts,
+ * we send UID/GID only along with "inode creation"
+ * fuse requests, otherwise idmap == &invalid_mnt_idmap and
+ * req->in.h.{u,g}id will be equal to FUSE_INVALID_UIDGID.
+ */
+ fsuid = no_idmap ? current_fsuid() : mapped_fsuid(idmap, fc->user_ns);
+ fsgid = no_idmap ? current_fsgid() : mapped_fsgid(idmap, fc->user_ns);
+ req->in.h.uid = from_kuid(fc->user_ns, fsuid);
+ req->in.h.gid = from_kgid(fc->user_ns, fsgid);
+
+ if (no_idmap && unlikely(req->in.h.uid == ((uid_t)-1) ||
+ req->in.h.gid == ((gid_t)-1))) {
+ fuse_put_request(req);
+ return ERR_PTR(-EOVERFLOW);
+ }
+
+ return req;
+
+ out:
+ fuse_drop_waiting(fc);
+ return ERR_PTR(err);
+}
+
+static void fuse_put_request(struct fuse_req *req)
+{
+ struct fuse_conn *fc = req->fm->fc;
+
+ if (refcount_dec_and_test(&req->count)) {
+ if (test_bit(FR_BACKGROUND, &req->flags)) {
+ /*
+ * We get here in the unlikely case that a background
+ * request was allocated but not sent
+ */
+ spin_lock(&fc->bg_lock);
+ if (!fc->blocked)
+ wake_up(&fc->blocked_waitq);
+ spin_unlock(&fc->bg_lock);
+ }
+
+ if (test_bit(FR_WAITING, &req->flags)) {
+ __clear_bit(FR_WAITING, &req->flags);
+ fuse_drop_waiting(fc);
+ }
+
+ fuse_request_free(req);
+ }
+}
+
+unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args)
+{
+ unsigned nbytes = 0;
+ unsigned i;
+
+ for (i = 0; i < numargs; i++)
+ nbytes += args[i].size;
+
+ return nbytes;
+}
+EXPORT_SYMBOL_GPL(fuse_len_args);
+
+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)
+__releases(fiq->lock)
+{
+ wake_up(&fiq->waitq);
+ kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
+ spin_unlock(&fiq->lock);
+}
+
+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);
+ } else {
+ kfree(forget);
+ spin_unlock(&fiq->lock);
+ }
+}
+
+void fuse_dev_queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
+{
+ spin_lock(&fiq->lock);
+ if (list_empty(&req->intr_entry)) {
+ list_add_tail(&req->intr_entry, &fiq->interrupts);
+ /*
+ * Pairs with smp_mb() implied by test_and_set_bit()
+ * from fuse_request_end().
+ */
+ smp_mb();
+ if (test_bit(FR_FINISHED, &req->flags)) {
+ list_del_init(&req->intr_entry);
+ spin_unlock(&fiq->lock);
+ } else {
+ fuse_dev_wake_and_unlock(fiq);
+ }
+ } 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)
+{
+ 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);
+ } else {
+ spin_unlock(&fiq->lock);
+ req->out.h.error = -ENOTCONN;
+ clear_bit(FR_PENDING, &req->flags);
+ fuse_request_end(req);
+ }
+}
+
+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,
+};
+EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops);
+
+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_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;
+
+ fiq->ops->send_forget(fiq, forget);
+}
+
+static void flush_bg_queue(struct fuse_conn *fc)
+{
+ struct fuse_iqueue *fiq = &fc->iq;
+
+ while (fc->active_background < fc->max_background &&
+ !list_empty(&fc->bg_queue)) {
+ struct fuse_req *req;
+
+ req = list_first_entry(&fc->bg_queue, struct fuse_req, list);
+ list_del(&req->list);
+ fc->active_background++;
+ fuse_send_one(fiq, req);
+ }
+}
+
+/*
+ * This function is called when a request is finished. Either a reply
+ * has arrived or it was aborted (and not yet sent) or some error
+ * occurred during communication with userspace, or the device file
+ * was closed. The requester thread is woken up (if still waiting),
+ * the 'end' callback is called if given, else the reference to the
+ * request is released
+ */
+void fuse_request_end(struct fuse_req *req)
+{
+ struct fuse_mount *fm = req->fm;
+ struct fuse_conn *fc = fm->fc;
+ struct fuse_iqueue *fiq = &fc->iq;
+
+ if (test_and_set_bit(FR_FINISHED, &req->flags))
+ goto put_request;
+
+ 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(&fc->bg_lock);
+ clear_bit(FR_BACKGROUND, &req->flags);
+ if (fc->num_background == fc->max_background) {
+ fc->blocked = 0;
+ wake_up(&fc->blocked_waitq);
+ } else if (!fc->blocked) {
+ /*
+ * Wake up next waiter, if any. It's okay to use
+ * waitqueue_active(), as we've already synced up
+ * fc->blocked with waiters with the wake_up() call
+ * above.
+ */
+ if (waitqueue_active(&fc->blocked_waitq))
+ wake_up(&fc->blocked_waitq);
+ }
+
+ fc->num_background--;
+ fc->active_background--;
+ flush_bg_queue(fc);
+ spin_unlock(&fc->bg_lock);
+ } else {
+ /* Wake up waiter sleeping in request_wait_answer() */
+ wake_up(&req->waitq);
+ }
+
+ if (test_bit(FR_ASYNC, &req->flags))
+ req->args->end(fm, req->args, req->out.h.error);
+put_request:
+ fuse_put_request(req);
+}
+EXPORT_SYMBOL_GPL(fuse_request_end);
+
+static int queue_interrupt(struct fuse_req *req)
+{
+ struct fuse_iqueue *fiq = &req->fm->fc->iq;
+
+ /* 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_conn *fc = req->fm->fc;
+ struct fuse_iqueue *fiq = &fc->iq;
+ int err;
+
+ if (!fc->no_interrupt) {
+ /* Any signal may interrupt this */
+ err = wait_event_interruptible(req->waitq,
+ test_bit(FR_FINISHED, &req->flags));
+ if (!err)
+ return;
+
+ set_bit(FR_INTERRUPTED, &req->flags);
+ /* matches barrier in fuse_dev_do_read() */
+ smp_mb__after_atomic();
+ if (test_bit(FR_SENT, &req->flags))
+ queue_interrupt(req);
+ }
+
+ if (!test_bit(FR_FORCE, &req->flags)) {
+ 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_abort_conn(fc);
+ return;
+ }
+
+ 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;
+ }
+
+ /*
+ * Either request is already in userspace, or it was forced.
+ * Wait it out.
+ */
+ wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
+}
+
+static void __fuse_request_send(struct fuse_req *req)
+{
+ struct fuse_iqueue *fiq = &req->fm->fc->iq;
+
+ BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
+
+ /* acquire extra reference, since request is still needed after
+ fuse_request_end() */
+ __fuse_get_request(req);
+ 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_conn *fc, struct fuse_args *args)
+{
+ if (fc->minor < 4 && args->opcode == FUSE_STATFS)
+ args->out_args[0].size = FUSE_COMPAT_STATFS_SIZE;
+
+ if (fc->minor < 9) {
+ switch (args->opcode) {
+ case FUSE_LOOKUP:
+ case FUSE_CREATE:
+ case FUSE_MKNOD:
+ case FUSE_MKDIR:
+ case FUSE_SYMLINK:
+ case FUSE_LINK:
+ args->out_args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
+ break;
+ case FUSE_GETATTR:
+ case FUSE_SETATTR:
+ args->out_args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
+ break;
+ }
+ }
+ if (fc->minor < 12) {
+ switch (args->opcode) {
+ case FUSE_CREATE:
+ args->in_args[0].size = sizeof(struct fuse_open_in);
+ break;
+ case FUSE_MKNOD:
+ args->in_args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
+ break;
+ }
+ }
+}
+
+static void fuse_force_creds(struct fuse_req *req)
+{
+ struct fuse_conn *fc = req->fm->fc;
+
+ if (!req->fm->sb || req->fm->sb->s_iflags & SB_I_NOIDMAP) {
+ req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
+ req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
+ } else {
+ req->in.h.uid = FUSE_INVALID_UIDGID;
+ req->in.h.gid = FUSE_INVALID_UIDGID;
+ }
+
+ req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
+}
+
+static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args)
+{
+ req->in.h.opcode = args->opcode;
+ req->in.h.nodeid = args->nodeid;
+ req->args = args;
+ if (args->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_simple_request(struct mnt_idmap *idmap,
+ struct fuse_mount *fm,
+ struct fuse_args *args)
+{
+ struct fuse_conn *fc = fm->fc;
+ struct fuse_req *req;
+ ssize_t ret;
+
+ if (args->force) {
+ atomic_inc(&fc->num_waiting);
+ req = fuse_request_alloc(fm, GFP_KERNEL | __GFP_NOFAIL);
+
+ if (!args->nocreds)
+ fuse_force_creds(req);
+
+ __set_bit(FR_WAITING, &req->flags);
+ if (!args->abort_on_kill)
+ __set_bit(FR_FORCE, &req->flags);
+ } else {
+ WARN_ON(args->nocreds);
+ req = fuse_get_req(idmap, fm, false);
+ if (IS_ERR(req))
+ return PTR_ERR(req);
+ }
+
+ /* Needs to be done after fuse_get_req() so that fc->minor is valid */
+ fuse_adjust_compat(fc, args);
+ fuse_args_to_req(req, args);
+
+ if (!args->noreply)
+ __set_bit(FR_ISREPLY, &req->flags);
+ __fuse_request_send(req);
+ ret = req->out.h.error;
+ if (!ret && args->out_argvar) {
+ BUG_ON(args->out_numargs == 0);
+ ret = args->out_args[args->out_numargs - 1].size;
+ }
+ fuse_put_request(req);
+
+ return ret;
+}
+
+#ifdef CONFIG_FUSE_IO_URING
+static bool fuse_request_queue_background_uring(struct fuse_conn *fc,
+ struct fuse_req *req)
+{
+ struct fuse_iqueue *fiq = &fc->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_mount *fm = req->fm;
+ struct fuse_conn *fc = fm->fc;
+ bool queued = false;
+
+ WARN_ON(!test_bit(FR_BACKGROUND, &req->flags));
+ if (!test_bit(FR_WAITING, &req->flags)) {
+ __set_bit(FR_WAITING, &req->flags);
+ atomic_inc(&fc->num_waiting);
+ }
+ __set_bit(FR_ISREPLY, &req->flags);
+
+#ifdef CONFIG_FUSE_IO_URING
+ if (fuse_uring_ready(fc))
+ return fuse_request_queue_background_uring(fc, req);
+#endif
+
+ spin_lock(&fc->bg_lock);
+ if (likely(fc->connected)) {
+ fc->num_background++;
+ if (fc->num_background == fc->max_background)
+ fc->blocked = 1;
+ list_add_tail(&req->list, &fc->bg_queue);
+ flush_bg_queue(fc);
+ queued = true;
+ }
+ spin_unlock(&fc->bg_lock);
+
+ return queued;
+}
+
+int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args,
+ gfp_t gfp_flags)
+{
+ struct fuse_req *req;
+
+ if (args->force) {
+ WARN_ON(!args->nocreds);
+ req = fuse_request_alloc(fm, gfp_flags);
+ if (!req)
+ return -ENOMEM;
+ __set_bit(FR_BACKGROUND, &req->flags);
+ } else {
+ WARN_ON(args->nocreds);
+ req = fuse_get_req(&invalid_mnt_idmap, fm, true);
+ if (IS_ERR(req))
+ return PTR_ERR(req);
+ }
+
+ fuse_args_to_req(req, args);
+
+ if (!fuse_request_queue_background(req)) {
+ fuse_put_request(req);
+ return -ENOTCONN;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fuse_simple_background);
+
+static int fuse_simple_notify_reply(struct fuse_mount *fm,
+ struct fuse_args *args, u64 unique)
+{
+ struct fuse_req *req;
+ struct fuse_iqueue *fiq = &fm->fc->iq;
+
+ req = fuse_get_req(&invalid_mnt_idmap, fm, false);
+ if (IS_ERR(req))
+ return PTR_ERR(req);
+
+ __clear_bit(FR_ISREPLY, &req->flags);
+ req->in.h.unique = unique;
+
+ fuse_args_to_req(req, args);
+
+ 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;
+
+ 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);
+
+ err = 0;
+ spin_lock(&cs->req->waitq.lock);
+ if (test_bit(FR_ABORTED, &cs->req->flags))
+ err = -ENOENT;
+ else
+ *foliop = newfolio;
+ spin_unlock(&cs->req->waitq.lock);
+
+ if (err) {
+ folio_unlock(newfolio);
+ folio_put(newfolio);
+ goto out_put_old;
+ }
+
+ 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 0;
+}
+
+/*
+ * Copy a folio in the request to/from the userspace buffer. Must be
+ * done atomically
+ */
+static 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)
+ folio_zero_range(folio, 0, size);
+ }
+
+ while (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 */
+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 */
+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_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,
+ size_t nbytes, struct fuse_req *req)
+__releases(fiq->lock)
+{
+ struct fuse_in_header ih;
+ struct fuse_interrupt_in arg;
+ unsigned reqsize = sizeof(ih) + sizeof(arg);
+ int err;
+
+ list_del_init(&req->intr_entry);
+ memset(&ih, 0, sizeof(ih));
+ memset(&arg, 0, sizeof(arg));
+ ih.len = reqsize;
+ ih.opcode = FUSE_INTERRUPT;
+ ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT);
+ arg.unique = req->in.h.unique;
+
+ spin_unlock(&fiq->lock);
+ if (nbytes < reqsize)
+ return -EINVAL;
+
+ err = fuse_copy_one(cs, &ih, sizeof(ih));
+ if (!err)
+ err = fuse_copy_one(cs, &arg, sizeof(arg));
+ fuse_copy_finish(cs);
+
+ return err ? err : reqsize;
+}
+
+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,
+ size_t nbytes)
+__releases(fiq->lock)
+{
+ int err;
+ struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL);
+ struct fuse_forget_in arg = {
+ .nlookup = forget->forget_one.nlookup,
+ };
+ struct fuse_in_header ih = {
+ .opcode = FUSE_FORGET,
+ .nodeid = forget->forget_one.nodeid,
+ .unique = fuse_get_unique_locked(fiq),
+ .len = sizeof(ih) + sizeof(arg),
+ };
+
+ spin_unlock(&fiq->lock);
+ kfree(forget);
+ if (nbytes < ih.len)
+ return -EINVAL;
+
+ err = fuse_copy_one(cs, &ih, sizeof(ih));
+ if (!err)
+ err = fuse_copy_one(cs, &arg, sizeof(arg));
+ fuse_copy_finish(cs);
+
+ if (err)
+ return err;
+
+ return ih.len;
+}
+
+static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
+ struct fuse_copy_state *cs, size_t nbytes)
+__releases(fiq->lock)
+{
+ int err;
+ unsigned max_forgets;
+ unsigned count;
+ struct fuse_forget_link *head;
+ struct fuse_batch_forget_in arg = { .count = 0 };
+ struct fuse_in_header ih = {
+ .opcode = FUSE_BATCH_FORGET,
+ .unique = fuse_get_unique_locked(fiq),
+ .len = sizeof(ih) + sizeof(arg),
+ };
+
+ if (nbytes < ih.len) {
+ spin_unlock(&fiq->lock);
+ return -EINVAL;
+ }
+
+ max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
+ head = fuse_dequeue_forget(fiq, max_forgets, &count);
+ spin_unlock(&fiq->lock);
+
+ arg.count = count;
+ ih.len += count * sizeof(struct fuse_forget_one);
+ err = fuse_copy_one(cs, &ih, sizeof(ih));
+ if (!err)
+ err = fuse_copy_one(cs, &arg, sizeof(arg));
+
+ while (head) {
+ struct fuse_forget_link *forget = head;
+
+ if (!err) {
+ err = fuse_copy_one(cs, &forget->forget_one,
+ sizeof(forget->forget_one));
+ }
+ head = forget->next;
+ kfree(forget);
+ }
+
+ fuse_copy_finish(cs);
+
+ if (err)
+ return err;
+
+ return ih.len;
+}
+
+static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
+ struct fuse_copy_state *cs,
+ size_t nbytes)
+__releases(fiq->lock)
+{
+ if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
+ return fuse_read_single_forget(fiq, cs, nbytes);
+ else
+ return fuse_read_batch_forget(fiq, cs, nbytes);
+}
+
+/*
+ * Read a single request into the userspace filesystem's buffer. This
+ * function waits until a request is available, then removes it from
+ * the pending list and copies request data to userspace buffer. If
+ * no reply is needed (FORGET) or request has been aborted or there
+ * was an error during the copying then it's finished by calling
+ * fuse_request_end(). Otherwise add it to the processing list, and set
+ * the 'sent' flag.
+ */
+static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
+ struct fuse_copy_state *cs, size_t nbytes)
+{
+ ssize_t err;
+ struct fuse_conn *fc = fud->fc;
+ struct fuse_iqueue *fiq = &fc->iq;
+ struct fuse_pqueue *fpq = &fud->pq;
+ struct fuse_req *req;
+ struct fuse_args *args;
+ unsigned reqsize;
+ unsigned int hash;
+
+ /*
+ * Require sane minimum read buffer - that has capacity for fixed part
+ * of any request header + negotiated max_write room for data.
+ *
+ * Historically libfuse reserves 4K for fixed header room, but e.g.
+ * GlusterFS reserves only 80 bytes
+ *
+ * = `sizeof(fuse_in_header) + sizeof(fuse_write_in)`
+ *
+ * which is the absolute minimum any sane filesystem should be using
+ * for header room.
+ */
+ if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER,
+ sizeof(struct fuse_in_header) +
+ sizeof(struct fuse_write_in) +
+ fc->max_write))
+ return -EINVAL;
+
+ restart:
+ for (;;) {
+ spin_lock(&fiq->lock);
+ if (!fiq->connected || request_pending(fiq))
+ break;
+ spin_unlock(&fiq->lock);
+
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+ err = wait_event_interruptible_exclusive(fiq->waitq,
+ !fiq->connected || request_pending(fiq));
+ if (err)
+ return err;
+ }
+
+ if (!fiq->connected) {
+ err = fc->aborted ? -ECONNABORTED : -ENODEV;
+ goto err_unlock;
+ }
+
+ if (!list_empty(&fiq->interrupts)) {
+ req = list_entry(fiq->interrupts.next, struct fuse_req,
+ intr_entry);
+ return fuse_read_interrupt(fiq, cs, nbytes, req);
+ }
+
+ if (forget_pending(fiq)) {
+ if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
+ return fuse_read_forget(fc, fiq, cs, nbytes);
+
+ if (fiq->forget_batch <= -8)
+ fiq->forget_batch = 16;
+ }
+
+ req = list_entry(fiq->pending.next, struct fuse_req, list);
+ clear_bit(FR_PENDING, &req->flags);
+ list_del_init(&req->list);
+ spin_unlock(&fiq->lock);
+
+ args = req->args;
+ reqsize = req->in.h.len;
+
+ /* If request is too large, reply with an error and restart the read */
+ if (nbytes < reqsize) {
+ req->out.h.error = -EIO;
+ /* SETXATTR is special, since it may contain too large data */
+ if (args->opcode == FUSE_SETXATTR)
+ req->out.h.error = -E2BIG;
+ fuse_request_end(req);
+ goto restart;
+ }
+ spin_lock(&fpq->lock);
+ /*
+ * Must not put request on fpq->io queue after having been shut down by
+ * fuse_abort_conn()
+ */
+ if (!fpq->connected) {
+ req->out.h.error = err = -ECONNABORTED;
+ goto out_end;
+
+ }
+ list_add(&req->list, &fpq->io);
+ spin_unlock(&fpq->lock);
+ cs->req = req;
+ err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h));
+ if (!err)
+ err = fuse_copy_args(cs, args->in_numargs, args->in_pages,
+ (struct fuse_arg *) args->in_args, 0);
+ fuse_copy_finish(cs);
+ spin_lock(&fpq->lock);
+ clear_bit(FR_LOCKED, &req->flags);
+ if (!fpq->connected) {
+ err = fc->aborted ? -ECONNABORTED : -ENODEV;
+ goto out_end;
+ }
+ if (err) {
+ req->out.h.error = -EIO;
+ goto out_end;
+ }
+ if (!test_bit(FR_ISREPLY, &req->flags)) {
+ err = reqsize;
+ goto out_end;
+ }
+ hash = fuse_req_hash(req->in.h.unique);
+ list_move_tail(&req->list, &fpq->processing[hash]);
+ __fuse_get_request(req);
+ set_bit(FR_SENT, &req->flags);
+ spin_unlock(&fpq->lock);
+ /* matches barrier in request_wait_answer() */
+ smp_mb__after_atomic();
+ if (test_bit(FR_INTERRUPTED, &req->flags))
+ queue_interrupt(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();
+
+ 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;
+
+ err = wait_event_interruptible(fuse_dev_waitq, fuse_dev_fc_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;
+}
+
+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;
+
+ if (size != sizeof(outarg))
+ return -EINVAL;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ return err;
+
+ fuse_copy_finish(cs);
+ return fuse_notify_poll_wakeup(fc, &outarg);
+}
+
+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;
+
+ if (size != sizeof(outarg))
+ return -EINVAL;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ return err;
+ fuse_copy_finish(cs);
+
+ down_read(&fc->killsb);
+ err = fuse_reverse_inval_inode(fc, outarg.ino,
+ outarg.off, outarg.len);
+ up_read(&fc->killsb);
+ return err;
+}
+
+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;
+ char *buf;
+ struct qstr name;
+
+ if (size < sizeof(outarg))
+ return -EINVAL;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ return err;
+
+ if (outarg.namelen > fc->name_max)
+ return -ENAMETOOLONG;
+
+ err = -EINVAL;
+ if (size != sizeof(outarg) + outarg.namelen + 1)
+ return -EINVAL;
+
+ buf = kzalloc(outarg.namelen + 1, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ name.name = buf;
+ name.len = outarg.namelen;
+ err = fuse_copy_one(cs, buf, outarg.namelen + 1);
+ if (err)
+ goto err;
+ fuse_copy_finish(cs);
+ buf[outarg.namelen] = 0;
+
+ down_read(&fc->killsb);
+ err = fuse_reverse_inval_entry(fc, outarg.parent, 0, &name, outarg.flags);
+ up_read(&fc->killsb);
+err:
+ kfree(buf);
+ 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;
+ char *buf;
+ struct qstr name;
+
+ if (size < sizeof(outarg))
+ return -EINVAL;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ return err;
+
+ if (outarg.namelen > fc->name_max)
+ return -ENAMETOOLONG;
+
+ if (size != sizeof(outarg) + outarg.namelen + 1)
+ return -EINVAL;
+
+ buf = kzalloc(outarg.namelen + 1, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ name.name = buf;
+ name.len = outarg.namelen;
+ err = fuse_copy_one(cs, buf, outarg.namelen + 1);
+ if (err)
+ goto err;
+ fuse_copy_finish(cs);
+ buf[outarg.namelen] = 0;
+
+ down_read(&fc->killsb);
+ err = fuse_reverse_inval_entry(fc, outarg.parent, outarg.child, &name, 0);
+ up_read(&fc->killsb);
+err:
+ kfree(buf);
+ 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;
+ unsigned int num;
+ loff_t file_size;
+ loff_t pos;
+ loff_t end;
+
+ if (size < sizeof(outarg))
+ return -EINVAL;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ return err;
+
+ if (size - sizeof(outarg) != outarg.size)
+ return -EINVAL;
+
+ if (outarg.offset >= MAX_LFS_FILESIZE)
+ return -EINVAL;
+
+ nodeid = outarg.nodeid;
+ pos = outarg.offset;
+ num = min(outarg.size, MAX_LFS_FILESIZE - pos);
+
+ down_read(&fc->killsb);
+
+ err = -ENOENT;
+ inode = fuse_ilookup(fc, nodeid, NULL);
+ if (!inode)
+ goto out_up_killsb;
+
+ mapping = inode->i_mapping;
+ file_size = i_size_read(inode);
+ end = pos + num;
+ if (end > file_size) {
+ file_size = end;
+ fuse_write_update_attr(inode, file_size, num);
+ }
+
+ while (num) {
+ struct folio *folio;
+ unsigned int folio_offset;
+ unsigned int nr_bytes;
+ pgoff_t index = pos >> PAGE_SHIFT;
+
+ folio = filemap_grab_folio(mapping, index);
+ err = PTR_ERR(folio);
+ if (IS_ERR(folio))
+ goto out_iput;
+
+ folio_offset = offset_in_folio(folio, pos);
+ nr_bytes = min(num, folio_size(folio) - folio_offset);
+
+ err = fuse_copy_folio(cs, &folio, folio_offset, nr_bytes, 0);
+ if (!folio_test_uptodate(folio) && !err && folio_offset == 0 &&
+ (nr_bytes == folio_size(folio) || file_size == end)) {
+ folio_zero_segment(folio, nr_bytes, folio_size(folio));
+ folio_mark_uptodate(folio);
+ }
+ folio_unlock(folio);
+ folio_put(folio);
+
+ if (err)
+ goto out_iput;
+
+ pos += nr_bytes;
+ num -= nr_bytes;
+ }
+
+ err = 0;
+
+out_iput:
+ iput(inode);
+out_up_killsb:
+ up_read(&fc->killsb);
+ return err;
+}
+
+struct fuse_retrieve_args {
+ struct fuse_args_pages ap;
+ struct fuse_notify_retrieve_in inarg;
+};
+
+static void fuse_retrieve_end(struct fuse_mount *fm, struct fuse_args *args,
+ int error)
+{
+ struct fuse_retrieve_args *ra =
+ container_of(args, typeof(*ra), ap.args);
+
+ release_pages(ra->ap.folios, ra->ap.num_folios);
+ kfree(ra);
+}
+
+static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,
+ struct fuse_notify_retrieve_out *outarg)
+{
+ int err;
+ struct address_space *mapping = inode->i_mapping;
+ loff_t file_size;
+ unsigned int num;
+ unsigned int offset;
+ size_t total_len = 0;
+ unsigned int num_pages;
+ struct fuse_conn *fc = fm->fc;
+ struct fuse_retrieve_args *ra;
+ size_t args_size = sizeof(*ra);
+ struct fuse_args_pages *ap;
+ struct fuse_args *args;
+ loff_t pos = outarg->offset;
+
+ offset = offset_in_page(pos);
+ file_size = i_size_read(inode);
+
+ num = min(outarg->size, fc->max_write);
+ if (pos > file_size)
+ num = 0;
+ else if (num > file_size - pos)
+ num = file_size - pos;
+
+ num_pages = DIV_ROUND_UP(num + offset, PAGE_SIZE);
+ num_pages = min(num_pages, fc->max_pages);
+ num = min(num, num_pages << PAGE_SHIFT);
+
+ args_size += num_pages * (sizeof(ap->folios[0]) + sizeof(ap->descs[0]));
+
+ ra = kzalloc(args_size, GFP_KERNEL);
+ if (!ra)
+ return -ENOMEM;
+
+ ap = &ra->ap;
+ ap->folios = (void *) (ra + 1);
+ ap->descs = (void *) (ap->folios + num_pages);
+
+ args = &ap->args;
+ args->nodeid = outarg->nodeid;
+ args->opcode = FUSE_NOTIFY_REPLY;
+ args->in_numargs = 3;
+ args->in_pages = true;
+ args->end = fuse_retrieve_end;
+
+ while (num && ap->num_folios < num_pages) {
+ struct folio *folio;
+ unsigned int folio_offset;
+ unsigned int nr_bytes;
+ pgoff_t index = pos >> PAGE_SHIFT;
+
+ folio = filemap_get_folio(mapping, index);
+ if (IS_ERR(folio))
+ break;
+
+ folio_offset = offset_in_folio(folio, pos);
+ nr_bytes = min(folio_size(folio) - folio_offset, num);
+
+ ap->folios[ap->num_folios] = folio;
+ ap->descs[ap->num_folios].offset = folio_offset;
+ ap->descs[ap->num_folios].length = nr_bytes;
+ ap->num_folios++;
+
+ pos += nr_bytes;
+ num -= nr_bytes;
+ total_len += nr_bytes;
+ }
+ ra->inarg.offset = outarg->offset;
+ ra->inarg.size = total_len;
+ fuse_set_zero_arg0(args);
+ args->in_args[1].size = sizeof(ra->inarg);
+ args->in_args[1].value = &ra->inarg;
+ args->in_args[2].size = total_len;
+
+ err = fuse_simple_notify_reply(fm, args, outarg->notify_unique);
+ if (err)
+ fuse_retrieve_end(fm, args, err);
+
+ return err;
+}
+
+static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
+ struct fuse_copy_state *cs)
+{
+ struct fuse_notify_retrieve_out outarg;
+ struct fuse_mount *fm;
+ struct inode *inode;
+ u64 nodeid;
+ int err;
+
+ if (size != sizeof(outarg))
+ return -EINVAL;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ return err;
+
+ fuse_copy_finish(cs);
+
+ if (outarg.offset >= MAX_LFS_FILESIZE)
+ return -EINVAL;
+
+ down_read(&fc->killsb);
+ err = -ENOENT;
+ nodeid = outarg.nodeid;
+
+ inode = fuse_ilookup(fc, nodeid, &fm);
+ if (inode) {
+ err = fuse_retrieve(fm, inode, &outarg);
+ iput(inode);
+ }
+ up_read(&fc->killsb);
+
+ return err;
+}
+
+/*
+ * 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.
+ */
+static void fuse_resend(struct fuse_conn *fc)
+{
+ struct fuse_dev *fud;
+ struct fuse_req *req, *next;
+ struct fuse_iqueue *fiq = &fc->iq;
+ LIST_HEAD(to_queue);
+ unsigned int i;
+
+ spin_lock(&fc->lock);
+ if (!fc->connected) {
+ spin_unlock(&fc->lock);
+ return;
+ }
+
+ list_for_each_entry(fud, &fc->devices, entry) {
+ struct fuse_pqueue *fpq = &fud->pq;
+
+ spin_lock(&fpq->lock);
+ for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
+ list_splice_tail_init(&fpq->processing[i], &to_queue);
+ spin_unlock(&fpq->lock);
+ }
+ spin_unlock(&fc->lock);
+
+ list_for_each_entry_safe(req, next, &to_queue, list) {
+ set_bit(FR_PENDING, &req->flags);
+ clear_bit(FR_SENT, &req->flags);
+ /* mark the request as resend request */
+ req->in.h.unique |= FUSE_UNIQUE_RESEND;
+ }
+
+ spin_lock(&fiq->lock);
+ if (!fiq->connected) {
+ spin_unlock(&fiq->lock);
+ list_for_each_entry(req, &to_queue, list)
+ clear_bit(FR_PENDING, &req->flags);
+ fuse_dev_end_requests(&to_queue);
+ return;
+ }
+ /* iq and pq requests are both oldest to newest */
+ list_splice(&to_queue, &fiq->pending);
+ fuse_dev_wake_and_unlock(fiq);
+}
+
+static int fuse_notify_resend(struct fuse_conn *fc)
+{
+ fuse_resend(fc);
+ return 0;
+}
+
+/*
+ * Increments the fuse connection epoch. This will result of dentries from
+ * previous epochs to be invalidated. Additionally, if inval_wq is set, a work
+ * queue is scheduled to trigger the invalidation.
+ */
+static int fuse_notify_inc_epoch(struct fuse_conn *fc)
+{
+ atomic_inc(&fc->epoch);
+ if (inval_wq)
+ schedule_work(&fc->epoch_work);
+
+ return 0;
+}
+
+static int fuse_notify_prune(struct fuse_conn *fc, unsigned int size,
+ struct fuse_copy_state *cs)
+{
+ struct fuse_notify_prune_out outarg;
+ const unsigned int batch = 512;
+ u64 *nodeids __free(kfree) = kmalloc(sizeof(u64) * batch, GFP_KERNEL);
+ unsigned int num, i;
+ int err;
+
+ if (!nodeids)
+ return -ENOMEM;
+
+ if (size < sizeof(outarg))
+ return -EINVAL;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ return err;
+
+ if (size - sizeof(outarg) != outarg.count * sizeof(u64))
+ return -EINVAL;
+
+ for (; outarg.count; outarg.count -= num) {
+ num = min(batch, outarg.count);
+ err = fuse_copy_one(cs, nodeids, num * sizeof(u64));
+ if (err)
+ return err;
+
+ scoped_guard(rwsem_read, &fc->killsb) {
+ for (i = 0; i < num; i++)
+ fuse_try_prune_one_inode(fc, nodeids[i]);
+ }
+ }
+ return 0;
+}
+
+static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
+ unsigned int size, struct fuse_copy_state *cs)
+{
+ /*
+ * Only allow notifications during while the connection is in an
+ * initialized and connected state
+ */
+ if (!fc->initialized || !fc->connected)
+ return -EINVAL;
+
+ /* Don't try to move folios (yet) */
+ cs->move_folios = false;
+
+ 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);
+
+ case FUSE_NOTIFY_RESEND:
+ return fuse_notify_resend(fc);
+
+ case FUSE_NOTIFY_INC_EPOCH:
+ return fuse_notify_inc_epoch(fc);
+
+ case FUSE_NOTIFY_PRUNE:
+ return fuse_notify_prune(fc, size, cs);
+
+ default:
+ return -EINVAL;
+ }
+}
+
+/* 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_conn *fc = fud->fc;
+ struct fuse_pqueue *fpq = &fud->pq;
+ struct fuse_req *req;
+ struct fuse_out_header oh;
+
+ err = -EINVAL;
+ if (nbytes < sizeof(struct fuse_out_header))
+ goto out;
+
+ err = fuse_copy_one(cs, &oh, sizeof(oh));
+ if (err)
+ goto copy_finish;
+
+ err = -EINVAL;
+ if (oh.len != nbytes)
+ goto copy_finish;
+
+ /*
+ * Zero oh.unique indicates unsolicited notification message
+ * and error contains notification code.
+ */
+ if (!oh.unique) {
+ err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
+ goto 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)
+ fc->no_interrupt = 1;
+ else if (oh.error == -EAGAIN)
+ err = queue_interrupt(req);
+
+ fuse_put_request(req);
+
+ goto copy_finish;
+ }
+
+ clear_bit(FR_SENT, &req->flags);
+ list_move(&req->list, &fpq->io);
+ req->out.h = oh;
+ set_bit(FR_LOCKED, &req->flags);
+ spin_unlock(&fpq->lock);
+ cs->req = req;
+ if (!req->args->page_replace)
+ cs->move_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->fc->iq;
+ poll_wait(file, &fiq->waitq, wait);
+
+ spin_lock(&fiq->lock);
+ if (!fiq->connected)
+ mask = EPOLLERR;
+ else if (request_pending(fiq))
+ mask |= EPOLLIN | EPOLLRDNORM;
+ spin_unlock(&fiq->lock);
+
+ return mask;
+}
+
+/* Abort all requests on the given list (pending or processing) */
+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);
+ }
+}
+
+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/fuse.rst).
+ *
+ * Aborting requests under I/O goes as follows: 1: Separate out unlocked
+ * requests, they should be finished off immediately. Locked requests will be
+ * finished after unlock; see unlock_request(). 2: Finish off the unlocked
+ * requests. It is possible that some request will finish before we can. This
+ * is OK, the request will in that case be removed from the list before we touch
+ * it.
+ */
+void fuse_abort_conn(struct fuse_conn *fc)
+{
+ struct fuse_iqueue *fiq = &fc->iq;
+
+ spin_lock(&fc->lock);
+ if (fc->connected) {
+ struct fuse_dev *fud;
+ struct fuse_req *req, *next;
+ LIST_HEAD(to_end);
+ unsigned int i;
+
+ if (fc->timeout.req_timeout)
+ cancel_delayed_work(&fc->timeout.work);
+
+ /* Background queuing checks fc->connected under bg_lock */
+ spin_lock(&fc->bg_lock);
+ fc->connected = 0;
+ spin_unlock(&fc->bg_lock);
+
+ fuse_set_initialized(fc);
+ list_for_each_entry(fud, &fc->devices, entry) {
+ struct fuse_pqueue *fpq = &fud->pq;
+
+ spin_lock(&fpq->lock);
+ fpq->connected = 0;
+ list_for_each_entry_safe(req, next, &fpq->io, list) {
+ req->out.h.error = -ECONNABORTED;
+ spin_lock(&req->waitq.lock);
+ set_bit(FR_ABORTED, &req->flags);
+ if (!test_bit(FR_LOCKED, &req->flags)) {
+ set_bit(FR_PRIVATE, &req->flags);
+ __fuse_get_request(req);
+ list_move(&req->list, &to_end);
+ }
+ spin_unlock(&req->waitq.lock);
+ }
+ for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
+ list_splice_tail_init(&fpq->processing[i],
+ &to_end);
+ spin_unlock(&fpq->lock);
+ }
+ spin_lock(&fc->bg_lock);
+ fc->blocked = 0;
+ fc->max_background = UINT_MAX;
+ flush_bg_queue(fc);
+ spin_unlock(&fc->bg_lock);
+
+ spin_lock(&fiq->lock);
+ fiq->connected = 0;
+ list_for_each_entry(req, &fiq->pending, list)
+ clear_bit(FR_PENDING, &req->flags);
+ list_splice_tail_init(&fiq->pending, &to_end);
+ while (forget_pending(fiq))
+ kfree(fuse_dequeue_forget(fiq, 1, NULL));
+ wake_up_all(&fiq->waitq);
+ spin_unlock(&fiq->lock);
+ kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
+ end_polls(fc);
+ wake_up_all(&fc->blocked_waitq);
+ spin_unlock(&fc->lock);
+
+ fuse_dev_end_requests(&to_end);
+
+ /*
+ * fc->lock must not be taken to avoid conflicts with io-uring
+ * locks
+ */
+ fuse_uring_abort(fc);
+ } else {
+ spin_unlock(&fc->lock);
+ }
+}
+EXPORT_SYMBOL_GPL(fuse_abort_conn);
+
+void fuse_wait_aborted(struct fuse_conn *fc)
+{
+ /* matches implicit memory barrier in fuse_drop_waiting() */
+ smp_mb();
+ wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
+
+ fuse_uring_wait_stopped_queues(fc);
+}
+
+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_conn *fc = xchg(&fud->fc, FUSE_DEV_FC_DISCONNECTED);
+
+ if (fc) {
+ struct fuse_pqueue *fpq = &fud->pq;
+ LIST_HEAD(to_end);
+ unsigned int i;
+ bool last;
+
+ 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);
+
+ fuse_dev_end_requests(&to_end);
+
+ spin_lock(&fc->lock);
+ list_del(&fud->entry);
+ /* Are we the last open device? */
+ last = list_empty(&fc->devices);
+ spin_unlock(&fc->lock);
+
+ if (last) {
+ WARN_ON(fc->iq.fasync != NULL);
+ fuse_abort_conn(fc);
+ }
+ fuse_conn_put(fc);
+ }
+ 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->fc->iq.fasync);
+}
+
+static long fuse_dev_ioctl_clone(struct file *file, __u32 __user *argp)
+{
+ int oldfd;
+ struct fuse_dev *fud, *new_fud;
+
+ 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);
+
+ new_fud = fuse_file_to_fud(file);
+ if (fuse_dev_fc_get(new_fud))
+ return -EINVAL;
+
+ fuse_dev_install(new_fud, fud->fc);
+
+ 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->fc, &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->fc, backing_id);
+}
+
+static long fuse_dev_ioctl_sync_init(struct file *file)
+{
+ int err = -EINVAL;
+ struct fuse_dev *fud = fuse_file_to_fud(file);
+
+ mutex_lock(&fuse_mutex);
+ if (!fuse_dev_fc_get(fud)) {
+ fud->sync_init = true;
+ err = 0;
+ }
+ mutex_unlock(&fuse_mutex);
+ return err;
+}
+
+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", fud->fc->dev);
+}
+#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 2026-10-28 20:18:38 +0000