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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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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; }
/* Make sure stores before this are seen on another CPU */ smp_wmb(); fch->initialized = 1; wake_up_all(&fch->blocked_waitq);}
static bool fuse_block_alloc(struct fuse_chan *fch, bool for_background){ return !fch->initialized || (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; }
/* Matches smp_wmb() in fuse_chan_set_initialized() */ smp_rmb();
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)__releases(fiq->lock){ 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); } 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); }}
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(&fch->blocked_waitq); 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_chan_io_uring_enable(struct fuse_chan *fch){ fch->io_uring = 1;}
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); 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->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); 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_URINGstatic 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) 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, ©); 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) 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, *next; 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++) list_splice_tail_init(&fpq->processing[i], &to_queue); spin_unlock(&fpq->lock); } spin_unlock(&fch->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; } /* * 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) { 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);}
/* 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; if (!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_FSstatic 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);}