--- /dev/null
+/*
+ FUSE: Filesystem in Userspace
+ Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
+
+ This program can be distributed under the terms of the GNU GPL.
+ See the file COPYING.
+*/
+
+#include "fuse_i.h"
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/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>
+
+MODULE_ALIAS_MISCDEV(FUSE_MINOR);
+MODULE_ALIAS("devname:fuse");
+
+static struct kmem_cache *fuse_req_cachep;
+
+static struct fuse_conn *fuse_get_conn(struct file *file)
+{
+ /*
+ * Lockless access is OK, because file->private data is set
+ * once during mount and is valid until the file is released.
+ */
+ return file->private_data;
+}
+
+static void fuse_request_init(struct fuse_req *req, struct page **pages,
+ struct fuse_page_desc *page_descs,
+ unsigned npages)
+{
+ memset(req, 0, sizeof(*req));
+ memset(pages, 0, sizeof(*pages) * npages);
+ memset(page_descs, 0, sizeof(*page_descs) * npages);
+ INIT_LIST_HEAD(&req->list);
+ INIT_LIST_HEAD(&req->intr_entry);
+ init_waitqueue_head(&req->waitq);
+ atomic_set(&req->count, 1);
+ req->pages = pages;
+ req->page_descs = page_descs;
+ req->max_pages = npages;
+}
+
+static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
+{
+ struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags);
+ if (req) {
+ struct page **pages;
+ struct fuse_page_desc *page_descs;
+
+ if (npages <= FUSE_REQ_INLINE_PAGES) {
+ pages = req->inline_pages;
+ page_descs = req->inline_page_descs;
+ } else {
+ pages = kmalloc(sizeof(struct page *) * npages, flags);
+ page_descs = kmalloc(sizeof(struct fuse_page_desc) *
+ npages, flags);
+ }
+
+ if (!pages || !page_descs) {
+ kfree(pages);
+ kfree(page_descs);
+ kmem_cache_free(fuse_req_cachep, req);
+ return NULL;
+ }
+
+ fuse_request_init(req, pages, page_descs, npages);
+ }
+ return req;
+}
+
+struct fuse_req *fuse_request_alloc(unsigned npages)
+{
+ return __fuse_request_alloc(npages, GFP_KERNEL);
+}
+EXPORT_SYMBOL_GPL(fuse_request_alloc);
+
+struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
+{
+ return __fuse_request_alloc(npages, GFP_NOFS);
+}
+
+void fuse_request_free(struct fuse_req *req)
+{
+ if (req->pages != req->inline_pages) {
+ kfree(req->pages);
+ kfree(req->page_descs);
+ }
+ kmem_cache_free(fuse_req_cachep, req);
+}
+
+static void block_sigs(sigset_t *oldset)
+{
+ sigset_t mask;
+
+ siginitsetinv(&mask, sigmask(SIGKILL));
+ sigprocmask(SIG_BLOCK, &mask, oldset);
+}
+
+static void restore_sigs(sigset_t *oldset)
+{
+ sigprocmask(SIG_SETMASK, oldset, NULL);
+}
+
+void __fuse_get_request(struct fuse_req *req)
+{
+ atomic_inc(&req->count);
+}
+
+/* Must be called with > 1 refcount */
+static void __fuse_put_request(struct fuse_req *req)
+{
+ BUG_ON(atomic_read(&req->count) < 2);
+ atomic_dec(&req->count);
+}
+
+static void fuse_req_init_context(struct fuse_req *req)
+{
+ req->in.h.uid = from_kuid_munged(&init_user_ns, current_fsuid());
+ req->in.h.gid = from_kgid_munged(&init_user_ns, current_fsgid());
+ req->in.h.pid = current->pid;
+}
+
+void fuse_set_initialized(struct fuse_conn *fc)
+{
+ /* Make sure stores before this are seen on another CPU */
+ smp_wmb();
+ fc->initialized = 1;
+}
+
+static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
+{
+ return !fc->initialized || (for_background && fc->blocked);
+}
+
+static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
+ bool for_background)
+{
+ struct fuse_req *req;
+ int err;
+ atomic_inc(&fc->num_waiting);
+
+ if (fuse_block_alloc(fc, for_background)) {
+ sigset_t oldset;
+ int intr;
+
+ block_sigs(&oldset);
+ intr = wait_event_interruptible_exclusive(fc->blocked_waitq,
+ !fuse_block_alloc(fc, for_background));
+ restore_sigs(&oldset);
+ err = -EINTR;
+ if (intr)
+ goto out;
+ }
+ /* Matches smp_wmb() in fuse_set_initialized() */
+ smp_rmb();
+
+ err = -ENOTCONN;
+ if (!fc->connected)
+ goto out;
+
+ req = fuse_request_alloc(npages);
+ err = -ENOMEM;
+ if (!req) {
+ if (for_background)
+ wake_up(&fc->blocked_waitq);
+ goto out;
+ }
+
+ fuse_req_init_context(req);
+ req->waiting = 1;
+ req->background = for_background;
+ return req;
+
+ out:
+ atomic_dec(&fc->num_waiting);
+ return ERR_PTR(err);
+}
+
+struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
+{
+ return __fuse_get_req(fc, npages, false);
+}
+EXPORT_SYMBOL_GPL(fuse_get_req);
+
+struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
+ unsigned npages)
+{
+ return __fuse_get_req(fc, npages, true);
+}
+EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
+
+/*
+ * Return request in fuse_file->reserved_req. However that may
+ * currently be in use. If that is the case, wait for it to become
+ * available.
+ */
+static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
+ struct file *file)
+{
+ struct fuse_req *req = NULL;
+ struct fuse_file *ff = file->private_data;
+
+ do {
+ wait_event(fc->reserved_req_waitq, ff->reserved_req);
+ spin_lock(&fc->lock);
+ if (ff->reserved_req) {
+ req = ff->reserved_req;
+ ff->reserved_req = NULL;
+ req->stolen_file = get_file(file);
+ }
+ spin_unlock(&fc->lock);
+ } while (!req);
+
+ return req;
+}
+
+/*
+ * Put stolen request back into fuse_file->reserved_req
+ */
+static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
+{
+ struct file *file = req->stolen_file;
+ struct fuse_file *ff = file->private_data;
+
+ spin_lock(&fc->lock);
+ fuse_request_init(req, req->pages, req->page_descs, req->max_pages);
+ BUG_ON(ff->reserved_req);
+ ff->reserved_req = req;
+ wake_up_all(&fc->reserved_req_waitq);
+ spin_unlock(&fc->lock);
+ fput(file);
+}
+
+/*
+ * Gets a requests for a file operation, always succeeds
+ *
+ * This is used for sending the FLUSH request, which must get to
+ * userspace, due to POSIX locks which may need to be unlocked.
+ *
+ * If allocation fails due to OOM, use the reserved request in
+ * fuse_file.
+ *
+ * This is very unlikely to deadlock accidentally, since the
+ * filesystem should not have it's own file open. If deadlock is
+ * intentional, it can still be broken by "aborting" the filesystem.
+ */
+struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
+ struct file *file)
+{
+ struct fuse_req *req;
+
+ atomic_inc(&fc->num_waiting);
+ wait_event(fc->blocked_waitq, fc->initialized);
+ /* Matches smp_wmb() in fuse_set_initialized() */
+ smp_rmb();
+ req = fuse_request_alloc(0);
+ if (!req)
+ req = get_reserved_req(fc, file);
+
+ fuse_req_init_context(req);
+ req->waiting = 1;
+ req->background = 0;
+ return req;
+}
+
+void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
+{
+ if (atomic_dec_and_test(&req->count)) {
+ if (unlikely(req->background)) {
+ /*
+ * We get here in the unlikely case that a background
+ * request was allocated but not sent
+ */
+ spin_lock(&fc->lock);
+ if (!fc->blocked)
+ wake_up(&fc->blocked_waitq);
+ spin_unlock(&fc->lock);
+ }
+
+ if (req->waiting)
+ atomic_dec(&fc->num_waiting);
+
+ if (req->stolen_file)
+ put_reserved_req(fc, req);
+ else
+ fuse_request_free(req);
+ }
+}
+EXPORT_SYMBOL_GPL(fuse_put_request);
+
+static unsigned len_args(unsigned numargs, struct fuse_arg *args)
+{
+ unsigned nbytes = 0;
+ unsigned i;
+
+ for (i = 0; i < numargs; i++)
+ nbytes += args[i].size;
+
+ return nbytes;
+}
+
+static u64 fuse_get_unique(struct fuse_conn *fc)
+{
+ fc->reqctr++;
+ /* zero is special */
+ if (fc->reqctr == 0)
+ fc->reqctr = 1;
+
+ return fc->reqctr;
+}
+
+static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
+{
+ req->in.h.len = sizeof(struct fuse_in_header) +
+ len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
+ list_add_tail(&req->list, &fc->pending);
+ req->state = FUSE_REQ_PENDING;
+ if (!req->waiting) {
+ req->waiting = 1;
+ atomic_inc(&fc->num_waiting);
+ }
+ wake_up(&fc->waitq);
+ kill_fasync(&fc->fasync, SIGIO, POLL_IN);
+}
+
+void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
+ u64 nodeid, u64 nlookup)
+{
+ forget->forget_one.nodeid = nodeid;
+ forget->forget_one.nlookup = nlookup;
+
+ spin_lock(&fc->lock);
+ if (fc->connected) {
+ fc->forget_list_tail->next = forget;
+ fc->forget_list_tail = forget;
+ wake_up(&fc->waitq);
+ kill_fasync(&fc->fasync, SIGIO, POLL_IN);
+ } else {
+ kfree(forget);
+ }
+ spin_unlock(&fc->lock);
+}
+
+static void flush_bg_queue(struct fuse_conn *fc)
+{
+ while (fc->active_background < fc->max_background &&
+ !list_empty(&fc->bg_queue)) {
+ struct fuse_req *req;
+
+ req = list_entry(fc->bg_queue.next, struct fuse_req, list);
+ list_del(&req->list);
+ fc->active_background++;
+ req->in.h.unique = fuse_get_unique(fc);
+ queue_request(fc, 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
+ *
+ * Called with fc->lock, unlocks it
+ */
+static void request_end(struct fuse_conn *fc, struct fuse_req *req)
+__releases(fc->lock)
+{
+ void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
+ req->end = NULL;
+ list_del(&req->list);
+ list_del(&req->intr_entry);
+ req->state = FUSE_REQ_FINISHED;
+ if (req->background) {
+ req->background = 0;
+
+ if (fc->num_background == fc->max_background)
+ fc->blocked = 0;
+
+ /* Wake up next waiter, if any */
+ if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
+ wake_up(&fc->blocked_waitq);
+
+ if (fc->num_background == fc->congestion_threshold &&
+ fc->connected && fc->bdi_initialized) {
+ clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
+ clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
+ }
+ fc->num_background--;
+ fc->active_background--;
+ flush_bg_queue(fc);
+ }
+ spin_unlock(&fc->lock);
+ wake_up(&req->waitq);
+ if (end)
+ end(fc, req);
+ fuse_put_request(fc, req);
+}
+
+static void wait_answer_interruptible(struct fuse_conn *fc,
+ struct fuse_req *req)
+__releases(fc->lock)
+__acquires(fc->lock)
+{
+ if (signal_pending(current))
+ return;
+
+ spin_unlock(&fc->lock);
+ wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
+ spin_lock(&fc->lock);
+}
+
+static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req)
+{
+ list_add_tail(&req->intr_entry, &fc->interrupts);
+ wake_up(&fc->waitq);
+ kill_fasync(&fc->fasync, SIGIO, POLL_IN);
+}
+
+static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
+__releases(fc->lock)
+__acquires(fc->lock)
+{
+ if (!fc->no_interrupt) {
+ /* Any signal may interrupt this */
+ wait_answer_interruptible(fc, req);
+
+ if (req->aborted)
+ goto aborted;
+ if (req->state == FUSE_REQ_FINISHED)
+ return;
+
+ req->interrupted = 1;
+ if (req->state == FUSE_REQ_SENT)
+ queue_interrupt(fc, req);
+ }
+
+ if (!req->force) {
+ sigset_t oldset;
+
+ /* Only fatal signals may interrupt this */
+ block_sigs(&oldset);
+ wait_answer_interruptible(fc, req);
+ restore_sigs(&oldset);
+
+ if (req->aborted)
+ goto aborted;
+ if (req->state == FUSE_REQ_FINISHED)
+ return;
+
+ /* Request is not yet in userspace, bail out */
+ if (req->state == FUSE_REQ_PENDING) {
+ list_del(&req->list);
+ __fuse_put_request(req);
+ req->out.h.error = -EINTR;
+ return;
+ }
+ }
+
+ /*
+ * Either request is already in userspace, or it was forced.
+ * Wait it out.
+ */
+ spin_unlock(&fc->lock);
+ wait_event(req->waitq, req->state == FUSE_REQ_FINISHED);
+ spin_lock(&fc->lock);
+
+ if (!req->aborted)
+ return;
+
+ aborted:
+ BUG_ON(req->state != FUSE_REQ_FINISHED);
+ if (req->locked) {
+ /* This is uninterruptible sleep, because data is
+ being copied to/from the buffers of req. During
+ locked state, there mustn't be any filesystem
+ operation (e.g. page fault), since that could lead
+ to deadlock */
+ spin_unlock(&fc->lock);
+ wait_event(req->waitq, !req->locked);
+ spin_lock(&fc->lock);
+ }
+}
+
+static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
+{
+ BUG_ON(req->background);
+ spin_lock(&fc->lock);
+ if (!fc->connected)
+ req->out.h.error = -ENOTCONN;
+ else if (fc->conn_error)
+ req->out.h.error = -ECONNREFUSED;
+ else {
+ req->in.h.unique = fuse_get_unique(fc);
+ queue_request(fc, req);
+ /* acquire extra reference, since request is still needed
+ after request_end() */
+ __fuse_get_request(req);
+
+ request_wait_answer(fc, req);
+ }
+ spin_unlock(&fc->lock);
+}
+
+void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
+{
+ req->isreply = 1;
+ __fuse_request_send(fc, req);
+}
+EXPORT_SYMBOL_GPL(fuse_request_send);
+
+static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
+{
+ if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
+ args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
+
+ if (fc->minor < 9) {
+ switch (args->in.h.opcode) {
+ case FUSE_LOOKUP:
+ case FUSE_CREATE:
+ case FUSE_MKNOD:
+ case FUSE_MKDIR:
+ case FUSE_SYMLINK:
+ case FUSE_LINK:
+ args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
+ break;
+ case FUSE_GETATTR:
+ case FUSE_SETATTR:
+ args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
+ break;
+ }
+ }
+ if (fc->minor < 12) {
+ switch (args->in.h.opcode) {
+ case FUSE_CREATE:
+ args->in.args[0].size = sizeof(struct fuse_open_in);
+ break;
+ case FUSE_MKNOD:
+ args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
+ break;
+ }
+ }
+}
+
+ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
+{
+ struct fuse_req *req;
+ ssize_t ret;
+
+ req = fuse_get_req(fc, 0);
+ if (IS_ERR(req))
+ return PTR_ERR(req);
+
+ /* Needs to be done after fuse_get_req() so that fc->minor is valid */
+ fuse_adjust_compat(fc, args);
+
+ req->in.h.opcode = args->in.h.opcode;
+ req->in.h.nodeid = args->in.h.nodeid;
+ req->in.numargs = args->in.numargs;
+ memcpy(req->in.args, args->in.args,
+ args->in.numargs * sizeof(struct fuse_in_arg));
+ req->out.argvar = args->out.argvar;
+ req->out.numargs = args->out.numargs;
+ memcpy(req->out.args, args->out.args,
+ args->out.numargs * sizeof(struct fuse_arg));
+ fuse_request_send(fc, req);
+ ret = req->out.h.error;
+ if (!ret && args->out.argvar) {
+ BUG_ON(args->out.numargs != 1);
+ ret = req->out.args[0].size;
+ }
+ fuse_put_request(fc, req);
+
+ return ret;
+}
+
+static void fuse_request_send_nowait_locked(struct fuse_conn *fc,
+ struct fuse_req *req)
+{
+ BUG_ON(!req->background);
+ fc->num_background++;
+ if (fc->num_background == fc->max_background)
+ fc->blocked = 1;
+ if (fc->num_background == fc->congestion_threshold &&
+ fc->bdi_initialized) {
+ set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
+ set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
+ }
+ list_add_tail(&req->list, &fc->bg_queue);
+ flush_bg_queue(fc);
+}
+
+static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
+{
+ spin_lock(&fc->lock);
+ if (fc->connected) {
+ fuse_request_send_nowait_locked(fc, req);
+ spin_unlock(&fc->lock);
+ } else {
+ req->out.h.error = -ENOTCONN;
+ request_end(fc, req);
+ }
+}
+
+void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
+{
+ req->isreply = 1;
+ fuse_request_send_nowait(fc, req);
+}
+EXPORT_SYMBOL_GPL(fuse_request_send_background);
+
+static int fuse_request_send_notify_reply(struct fuse_conn *fc,
+ struct fuse_req *req, u64 unique)
+{
+ int err = -ENODEV;
+
+ req->isreply = 0;
+ req->in.h.unique = unique;
+ spin_lock(&fc->lock);
+ if (fc->connected) {
+ queue_request(fc, req);
+ err = 0;
+ }
+ spin_unlock(&fc->lock);
+
+ return err;
+}
+
+/*
+ * Called under fc->lock
+ *
+ * fc->connected must have been checked previously
+ */
+void fuse_request_send_background_locked(struct fuse_conn *fc,
+ struct fuse_req *req)
+{
+ req->isreply = 1;
+ fuse_request_send_nowait_locked(fc, req);
+}
+
+void fuse_force_forget(struct file *file, u64 nodeid)
+{
+ struct inode *inode = file_inode(file);
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_req *req;
+ struct fuse_forget_in inarg;
+
+ memset(&inarg, 0, sizeof(inarg));
+ inarg.nlookup = 1;
+ req = fuse_get_req_nofail_nopages(fc, file);
+ req->in.h.opcode = FUSE_FORGET;
+ req->in.h.nodeid = nodeid;
+ req->in.numargs = 1;
+ req->in.args[0].size = sizeof(inarg);
+ req->in.args[0].value = &inarg;
+ req->isreply = 0;
+ __fuse_request_send(fc, req);
+ /* ignore errors */
+ fuse_put_request(fc, req);
+}
+
+/*
+ * Lock the request. Up to the next unlock_request() there mustn't be
+ * anything that could cause a page-fault. If the request was already
+ * aborted bail out.
+ */
+static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
+{
+ int err = 0;
+ if (req) {
+ spin_lock(&fc->lock);
+ if (req->aborted)
+ err = -ENOENT;
+ else
+ req->locked = 1;
+ spin_unlock(&fc->lock);
+ }
+ return err;
+}
+
+/*
+ * Unlock request. If it was aborted during being locked, the
+ * requester thread is currently waiting for it to be unlocked, so
+ * wake it up.
+ */
+static void unlock_request(struct fuse_conn *fc, struct fuse_req *req)
+{
+ if (req) {
+ spin_lock(&fc->lock);
+ req->locked = 0;
+ if (req->aborted)
+ wake_up(&req->waitq);
+ spin_unlock(&fc->lock);
+ }
+}
+
+struct fuse_copy_state {
+ struct fuse_conn *fc;
+ int write;
+ struct fuse_req *req;
+ struct iov_iter *iter;
+ struct pipe_buffer *pipebufs;
+ struct pipe_buffer *currbuf;
+ struct pipe_inode_info *pipe;
+ unsigned long nr_segs;
+ struct page *pg;
+ unsigned len;
+ unsigned offset;
+ unsigned move_pages:1;
+};
+
+static void fuse_copy_init(struct fuse_copy_state *cs,
+ struct fuse_conn *fc,
+ int write,
+ struct iov_iter *iter)
+{
+ memset(cs, 0, sizeof(*cs));
+ cs->fc = fc;
+ cs->write = write;
+ cs->iter = iter;
+}
+
+/* Unmap and put previous page of userspace buffer */
+static void fuse_copy_finish(struct fuse_copy_state *cs)
+{
+ if (cs->currbuf) {
+ struct pipe_buffer *buf = cs->currbuf;
+
+ if (cs->write)
+ buf->len = PAGE_SIZE - cs->len;
+ cs->currbuf = NULL;
+ } else if (cs->pg) {
+ if (cs->write) {
+ flush_dcache_page(cs->pg);
+ set_page_dirty_lock(cs->pg);
+ }
+ put_page(cs->pg);
+ }
+ cs->pg = NULL;
+}
+
+/*
+ * Get another pagefull of userspace buffer, and map it to kernel
+ * address space, and lock request
+ */
+static int fuse_copy_fill(struct fuse_copy_state *cs)
+{
+ struct page *page;
+ int err;
+
+ unlock_request(cs->fc, cs->req);
+ fuse_copy_finish(cs);
+ if (cs->pipebufs) {
+ struct pipe_buffer *buf = cs->pipebufs;
+
+ if (!cs->write) {
+ err = buf->ops->confirm(cs->pipe, buf);
+ if (err)
+ return err;
+
+ BUG_ON(!cs->nr_segs);
+ cs->currbuf = buf;
+ cs->pg = buf->page;
+ cs->offset = buf->offset;
+ cs->len = buf->len;
+ cs->pipebufs++;
+ cs->nr_segs--;
+ } else {
+ if (cs->nr_segs == cs->pipe->buffers)
+ return -EIO;
+
+ page = alloc_page(GFP_HIGHUSER);
+ if (!page)
+ return -ENOMEM;
+
+ buf->page = page;
+ buf->offset = 0;
+ buf->len = 0;
+
+ cs->currbuf = buf;
+ cs->pg = page;
+ cs->offset = 0;
+ cs->len = PAGE_SIZE;
+ cs->pipebufs++;
+ cs->nr_segs++;
+ }
+ } else {
+ size_t off;
+ err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
+ if (err < 0)
+ return err;
+ BUG_ON(!err);
+ cs->len = err;
+ cs->offset = off;
+ cs->pg = page;
+ cs->offset = off;
+ iov_iter_advance(cs->iter, err);
+ }
+
+ return lock_request(cs->fc, cs->req);
+}
+
+/* Do as much copy to/from userspace buffer as we can */
+static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
+{
+ unsigned ncpy = min(*size, cs->len);
+ if (val) {
+ void *pgaddr = kmap_atomic(cs->pg);
+ void *buf = pgaddr + cs->offset;
+
+ if (cs->write)
+ memcpy(buf, *val, ncpy);
+ else
+ memcpy(*val, buf, ncpy);
+
+ kunmap_atomic(pgaddr);
+ *val += ncpy;
+ }
+ *size -= ncpy;
+ cs->len -= ncpy;
+ cs->offset += ncpy;
+ return ncpy;
+}
+
+static int fuse_check_page(struct page *page)
+{
+ if (page_mapcount(page) ||
+ page->mapping != NULL ||
+ page_count(page) != 1 ||
+ (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
+ ~(1 << PG_locked |
+ 1 << PG_referenced |
+ 1 << PG_uptodate |
+ 1 << PG_lru |
+ 1 << PG_active |
+ 1 << PG_reclaim))) {
+ printk(KERN_WARNING "fuse: trying to steal weird page\n");
+ printk(KERN_WARNING " page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);
+ return 1;
+ }
+ return 0;
+}
+
+static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
+{
+ int err;
+ struct page *oldpage = *pagep;
+ struct page *newpage;
+ struct pipe_buffer *buf = cs->pipebufs;
+
+ unlock_request(cs->fc, cs->req);
+ fuse_copy_finish(cs);
+
+ err = buf->ops->confirm(cs->pipe, buf);
+ if (err)
+ return err;
+
+ BUG_ON(!cs->nr_segs);
+ cs->currbuf = buf;
+ cs->len = buf->len;
+ cs->pipebufs++;
+ cs->nr_segs--;
+
+ if (cs->len != PAGE_SIZE)
+ goto out_fallback;
+
+ if (buf->ops->steal(cs->pipe, buf) != 0)
+ goto out_fallback;
+
+ newpage = buf->page;
+
+ if (!PageUptodate(newpage))
+ SetPageUptodate(newpage);
+
+ ClearPageMappedToDisk(newpage);
+
+ if (fuse_check_page(newpage) != 0)
+ goto out_fallback_unlock;
+
+ /*
+ * This is a new and locked page, it shouldn't be mapped or
+ * have any special flags on it
+ */
+ if (WARN_ON(page_mapped(oldpage)))
+ goto out_fallback_unlock;
+ if (WARN_ON(page_has_private(oldpage)))
+ goto out_fallback_unlock;
+ if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
+ goto out_fallback_unlock;
+ if (WARN_ON(PageMlocked(oldpage)))
+ goto out_fallback_unlock;
+
+ err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
+ if (err) {
+ unlock_page(newpage);
+ return err;
+ }
+
+ page_cache_get(newpage);
+
+ if (!(buf->flags & PIPE_BUF_FLAG_LRU))
+ lru_cache_add_file(newpage);
+
+ err = 0;
+ spin_lock(&cs->fc->lock);
+ if (cs->req->aborted)
+ err = -ENOENT;
+ else
+ *pagep = newpage;
+ spin_unlock(&cs->fc->lock);
+
+ if (err) {
+ unlock_page(newpage);
+ page_cache_release(newpage);
+ return err;
+ }
+
+ unlock_page(oldpage);
+ page_cache_release(oldpage);
+ cs->len = 0;
+
+ return 0;
+
+out_fallback_unlock:
+ unlock_page(newpage);
+out_fallback:
+ cs->pg = buf->page;
+ cs->offset = buf->offset;
+
+ err = lock_request(cs->fc, cs->req);
+ if (err)
+ return err;
+
+ return 1;
+}
+
+static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
+ unsigned offset, unsigned count)
+{
+ struct pipe_buffer *buf;
+
+ if (cs->nr_segs == cs->pipe->buffers)
+ return -EIO;
+
+ unlock_request(cs->fc, cs->req);
+ fuse_copy_finish(cs);
+
+ buf = cs->pipebufs;
+ page_cache_get(page);
+ buf->page = page;
+ buf->offset = offset;
+ buf->len = count;
+
+ cs->pipebufs++;
+ cs->nr_segs++;
+ cs->len = 0;
+
+ return 0;
+}
+
+/*
+ * Copy a page in the request to/from the userspace buffer. Must be
+ * done atomically
+ */
+static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
+ unsigned offset, unsigned count, int zeroing)
+{
+ int err;
+ struct page *page = *pagep;
+
+ if (page && zeroing && count < PAGE_SIZE)
+ clear_highpage(page);
+
+ while (count) {
+ if (cs->write && cs->pipebufs && page) {
+ return fuse_ref_page(cs, page, offset, count);
+ } else if (!cs->len) {
+ if (cs->move_pages && page &&
+ offset == 0 && count == PAGE_SIZE) {
+ err = fuse_try_move_page(cs, pagep);
+ if (err <= 0)
+ return err;
+ } else {
+ err = fuse_copy_fill(cs);
+ if (err)
+ return err;
+ }
+ }
+ if (page) {
+ void *mapaddr = kmap_atomic(page);
+ void *buf = mapaddr + offset;
+ offset += fuse_copy_do(cs, &buf, &count);
+ kunmap_atomic(mapaddr);
+ } else
+ offset += fuse_copy_do(cs, NULL, &count);
+ }
+ if (page && !cs->write)
+ flush_dcache_page(page);
+ return 0;
+}
+
+/* Copy pages in the request to/from userspace buffer */
+static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
+ int zeroing)
+{
+ unsigned i;
+ struct fuse_req *req = cs->req;
+
+ for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
+ int err;
+ unsigned offset = req->page_descs[i].offset;
+ unsigned count = min(nbytes, req->page_descs[i].length);
+
+ err = fuse_copy_page(cs, &req->pages[i], offset, count,
+ zeroing);
+ if (err)
+ return err;
+
+ nbytes -= count;
+ }
+ return 0;
+}
+
+/* Copy a single argument in the request to/from userspace buffer */
+static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
+{
+ while (size) {
+ if (!cs->len) {
+ int err = fuse_copy_fill(cs);
+ if (err)
+ return err;
+ }
+ fuse_copy_do(cs, &val, &size);
+ }
+ return 0;
+}
+
+/* Copy request arguments to/from userspace buffer */
+static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
+ unsigned argpages, struct fuse_arg *args,
+ int zeroing)
+{
+ int err = 0;
+ unsigned i;
+
+ for (i = 0; !err && i < numargs; i++) {
+ struct fuse_arg *arg = &args[i];
+ if (i == numargs - 1 && argpages)
+ err = fuse_copy_pages(cs, arg->size, zeroing);
+ else
+ err = fuse_copy_one(cs, arg->value, arg->size);
+ }
+ return err;
+}
+
+static int forget_pending(struct fuse_conn *fc)
+{
+ return fc->forget_list_head.next != NULL;
+}
+
+static int request_pending(struct fuse_conn *fc)
+{
+ return !list_empty(&fc->pending) || !list_empty(&fc->interrupts) ||
+ forget_pending(fc);
+}
+
+/* Wait until a request is available on the pending list */
+static void request_wait(struct fuse_conn *fc)
+__releases(fc->lock)
+__acquires(fc->lock)
+{
+ DECLARE_WAITQUEUE(wait, current);
+
+ add_wait_queue_exclusive(&fc->waitq, &wait);
+ while (fc->connected && !request_pending(fc)) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (signal_pending(current))
+ break;
+
+ spin_unlock(&fc->lock);
+ schedule();
+ spin_lock(&fc->lock);
+ }
+ set_current_state(TASK_RUNNING);
+ remove_wait_queue(&fc->waitq, &wait);
+}
+
+/*
+ * 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 fc->lock held, releases it
+ */
+static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_copy_state *cs,
+ size_t nbytes, struct fuse_req *req)
+__releases(fc->lock)
+{
+ struct fuse_in_header ih;
+ struct fuse_interrupt_in arg;
+ unsigned reqsize = sizeof(ih) + sizeof(arg);
+ int err;
+
+ list_del_init(&req->intr_entry);
+ req->intr_unique = fuse_get_unique(fc);
+ memset(&ih, 0, sizeof(ih));
+ memset(&arg, 0, sizeof(arg));
+ ih.len = reqsize;
+ ih.opcode = FUSE_INTERRUPT;
+ ih.unique = req->intr_unique;
+ arg.unique = req->in.h.unique;
+
+ spin_unlock(&fc->lock);
+ if (nbytes < reqsize)
+ return -EINVAL;
+
+ err = fuse_copy_one(cs, &ih, sizeof(ih));
+ if (!err)
+ err = fuse_copy_one(cs, &arg, sizeof(arg));
+ fuse_copy_finish(cs);
+
+ return err ? err : reqsize;
+}
+
+static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc,
+ unsigned max,
+ unsigned *countp)
+{
+ struct fuse_forget_link *head = fc->forget_list_head.next;
+ struct fuse_forget_link **newhead = &head;
+ unsigned count;
+
+ for (count = 0; *newhead != NULL && count < max; count++)
+ newhead = &(*newhead)->next;
+
+ fc->forget_list_head.next = *newhead;
+ *newhead = NULL;
+ if (fc->forget_list_head.next == NULL)
+ fc->forget_list_tail = &fc->forget_list_head;
+
+ if (countp != NULL)
+ *countp = count;
+
+ return head;
+}
+
+static int fuse_read_single_forget(struct fuse_conn *fc,
+ struct fuse_copy_state *cs,
+ size_t nbytes)
+__releases(fc->lock)
+{
+ int err;
+ struct fuse_forget_link *forget = dequeue_forget(fc, 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(fc),
+ .len = sizeof(ih) + sizeof(arg),
+ };
+
+ spin_unlock(&fc->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_conn *fc,
+ struct fuse_copy_state *cs, size_t nbytes)
+__releases(fc->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(fc),
+ .len = sizeof(ih) + sizeof(arg),
+ };
+
+ if (nbytes < ih.len) {
+ spin_unlock(&fc->lock);
+ return -EINVAL;
+ }
+
+ max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
+ head = dequeue_forget(fc, max_forgets, &count);
+ spin_unlock(&fc->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_copy_state *cs,
+ size_t nbytes)
+__releases(fc->lock)
+{
+ if (fc->minor < 16 || fc->forget_list_head.next->next == NULL)
+ return fuse_read_single_forget(fc, cs, nbytes);
+ else
+ return fuse_read_batch_forget(fc, cs, nbytes);
+}
+
+/*
+ * Read a single request into the userspace filesystem's buffer. This
+ * function waits until a request is available, then removes it from
+ * the pending list and copies request data to userspace buffer. If
+ * no reply is needed (FORGET) or request has been aborted or there
+ * was an error during the copying then it's finished by calling
+ * request_end(). Otherwise add it to the processing list, and set
+ * the 'sent' flag.
+ */
+static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
+ struct fuse_copy_state *cs, size_t nbytes)
+{
+ int err;
+ struct fuse_req *req;
+ struct fuse_in *in;
+ unsigned reqsize;
+
+ restart:
+ spin_lock(&fc->lock);
+ err = -EAGAIN;
+ if ((file->f_flags & O_NONBLOCK) && fc->connected &&
+ !request_pending(fc))
+ goto err_unlock;
+
+ request_wait(fc);
+ err = -ENODEV;
+ if (!fc->connected)
+ goto err_unlock;
+ err = -ERESTARTSYS;
+ if (!request_pending(fc))
+ goto err_unlock;
+
+ if (!list_empty(&fc->interrupts)) {
+ req = list_entry(fc->interrupts.next, struct fuse_req,
+ intr_entry);
+ return fuse_read_interrupt(fc, cs, nbytes, req);
+ }
+
+ if (forget_pending(fc)) {
+ if (list_empty(&fc->pending) || fc->forget_batch-- > 0)
+ return fuse_read_forget(fc, cs, nbytes);
+
+ if (fc->forget_batch <= -8)
+ fc->forget_batch = 16;
+ }
+
+ req = list_entry(fc->pending.next, struct fuse_req, list);
+ req->state = FUSE_REQ_READING;
+ list_move(&req->list, &fc->io);
+
+ in = &req->in;
+ reqsize = 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 (in->h.opcode == FUSE_SETXATTR)
+ req->out.h.error = -E2BIG;
+ request_end(fc, req);
+ goto restart;
+ }
+ spin_unlock(&fc->lock);
+ cs->req = req;
+ err = fuse_copy_one(cs, &in->h, sizeof(in->h));
+ if (!err)
+ err = fuse_copy_args(cs, in->numargs, in->argpages,
+ (struct fuse_arg *) in->args, 0);
+ fuse_copy_finish(cs);
+ spin_lock(&fc->lock);
+ req->locked = 0;
+ if (req->aborted) {
+ request_end(fc, req);
+ return -ENODEV;
+ }
+ if (err) {
+ req->out.h.error = -EIO;
+ request_end(fc, req);
+ return err;
+ }
+ if (!req->isreply)
+ request_end(fc, req);
+ else {
+ req->state = FUSE_REQ_SENT;
+ list_move_tail(&req->list, &fc->processing);
+ if (req->interrupted)
+ queue_interrupt(fc, req);
+ spin_unlock(&fc->lock);
+ }
+ return reqsize;
+
+ err_unlock:
+ spin_unlock(&fc->lock);
+ return err;
+}
+
+static int fuse_dev_open(struct inode *inode, struct file *file)
+{
+ /*
+ * The fuse device's file's private_data is used to hold
+ * the fuse_conn(ection) when it is mounted, and is used to
+ * keep track of whether the file has been mounted already.
+ */
+ file->private_data = NULL;
+ return 0;
+}
+
+static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
+{
+ struct fuse_copy_state cs;
+ struct file *file = iocb->ki_filp;
+ struct fuse_conn *fc = fuse_get_conn(file);
+ if (!fc)
+ return -EPERM;
+
+ if (!iter_is_iovec(to))
+ return -EINVAL;
+
+ fuse_copy_init(&cs, fc, 1, to);
+
+ return fuse_dev_do_read(fc, 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 ret;
+ int page_nr = 0;
+ int do_wakeup = 0;
+ struct pipe_buffer *bufs;
+ struct fuse_copy_state cs;
+ struct fuse_conn *fc = fuse_get_conn(in);
+ if (!fc)
+ return -EPERM;
+
+ bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
+ if (!bufs)
+ return -ENOMEM;
+
+ fuse_copy_init(&cs, fc, 1, NULL);
+ cs.pipebufs = bufs;
+ cs.pipe = pipe;
+ ret = fuse_dev_do_read(fc, in, &cs, len);
+ if (ret < 0)
+ goto out;
+
+ ret = 0;
+ pipe_lock(pipe);
+
+ if (!pipe->readers) {
+ send_sig(SIGPIPE, current, 0);
+ if (!ret)
+ ret = -EPIPE;
+ goto out_unlock;
+ }
+
+ if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
+ ret = -EIO;
+ goto out_unlock;
+ }
+
+ while (page_nr < cs.nr_segs) {
+ int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
+ struct pipe_buffer *buf = pipe->bufs + newbuf;
+
+ buf->page = bufs[page_nr].page;
+ buf->offset = bufs[page_nr].offset;
+ buf->len = bufs[page_nr].len;
+ /*
+ * Need to be careful about this. Having buf->ops in module
+ * code can Oops if the buffer persists after module unload.
+ */
+ buf->ops = &nosteal_pipe_buf_ops;
+
+ pipe->nrbufs++;
+ page_nr++;
+ ret += buf->len;
+
+ if (pipe->files)
+ do_wakeup = 1;
+ }
+
+out_unlock:
+ pipe_unlock(pipe);
+
+ if (do_wakeup) {
+ smp_mb();
+ if (waitqueue_active(&pipe->wait))
+ wake_up_interruptible(&pipe->wait);
+ kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
+ }
+
+out:
+ for (; page_nr < cs.nr_segs; page_nr++)
+ page_cache_release(bufs[page_nr].page);
+
+ kfree(bufs);
+ return ret;
+}
+
+static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
+ struct fuse_copy_state *cs)
+{
+ struct fuse_notify_poll_wakeup_out outarg;
+ int err = -EINVAL;
+
+ if (size != sizeof(outarg))
+ goto err;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ goto err;
+
+ fuse_copy_finish(cs);
+ return fuse_notify_poll_wakeup(fc, &outarg);
+
+err:
+ fuse_copy_finish(cs);
+ return err;
+}
+
+static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
+ struct fuse_copy_state *cs)
+{
+ struct fuse_notify_inval_inode_out outarg;
+ int err = -EINVAL;
+
+ if (size != sizeof(outarg))
+ goto err;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ goto err;
+ fuse_copy_finish(cs);
+
+ down_read(&fc->killsb);
+ err = -ENOENT;
+ if (fc->sb) {
+ err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
+ outarg.off, outarg.len);
+ }
+ up_read(&fc->killsb);
+ return err;
+
+err:
+ fuse_copy_finish(cs);
+ return err;
+}
+
+static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
+ struct fuse_copy_state *cs)
+{
+ struct fuse_notify_inval_entry_out outarg;
+ int err = -ENOMEM;
+ char *buf;
+ struct qstr name;
+
+ buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
+ if (!buf)
+ goto err;
+
+ err = -EINVAL;
+ if (size < sizeof(outarg))
+ goto err;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ goto err;
+
+ err = -ENAMETOOLONG;
+ if (outarg.namelen > FUSE_NAME_MAX)
+ goto err;
+
+ err = -EINVAL;
+ if (size != sizeof(outarg) + outarg.namelen + 1)
+ goto err;
+
+ name.name = buf;
+ name.len = outarg.namelen;
+ err = fuse_copy_one(cs, buf, outarg.namelen + 1);
+ if (err)
+ goto err;
+ fuse_copy_finish(cs);
+ buf[outarg.namelen] = 0;
+ name.hash = full_name_hash(name.name, name.len);
+
+ down_read(&fc->killsb);
+ err = -ENOENT;
+ if (fc->sb)
+ err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
+ up_read(&fc->killsb);
+ kfree(buf);
+ return err;
+
+err:
+ kfree(buf);
+ fuse_copy_finish(cs);
+ return err;
+}
+
+static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
+ struct fuse_copy_state *cs)
+{
+ struct fuse_notify_delete_out outarg;
+ int err = -ENOMEM;
+ char *buf;
+ struct qstr name;
+
+ buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
+ if (!buf)
+ goto err;
+
+ err = -EINVAL;
+ if (size < sizeof(outarg))
+ goto err;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ goto err;
+
+ err = -ENAMETOOLONG;
+ if (outarg.namelen > FUSE_NAME_MAX)
+ goto err;
+
+ err = -EINVAL;
+ if (size != sizeof(outarg) + outarg.namelen + 1)
+ goto err;
+
+ name.name = buf;
+ name.len = outarg.namelen;
+ err = fuse_copy_one(cs, buf, outarg.namelen + 1);
+ if (err)
+ goto err;
+ fuse_copy_finish(cs);
+ buf[outarg.namelen] = 0;
+ name.hash = full_name_hash(name.name, name.len);
+
+ down_read(&fc->killsb);
+ err = -ENOENT;
+ if (fc->sb)
+ err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
+ outarg.child, &name);
+ up_read(&fc->killsb);
+ kfree(buf);
+ return err;
+
+err:
+ kfree(buf);
+ fuse_copy_finish(cs);
+ return err;
+}
+
+static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
+ struct fuse_copy_state *cs)
+{
+ struct fuse_notify_store_out outarg;
+ struct inode *inode;
+ struct address_space *mapping;
+ u64 nodeid;
+ int err;
+ pgoff_t index;
+ unsigned int offset;
+ unsigned int num;
+ loff_t file_size;
+ loff_t end;
+
+ err = -EINVAL;
+ if (size < sizeof(outarg))
+ goto out_finish;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ goto out_finish;
+
+ err = -EINVAL;
+ if (size - sizeof(outarg) != outarg.size)
+ goto out_finish;
+
+ nodeid = outarg.nodeid;
+
+ down_read(&fc->killsb);
+
+ err = -ENOENT;
+ if (!fc->sb)
+ goto out_up_killsb;
+
+ inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
+ if (!inode)
+ goto out_up_killsb;
+
+ mapping = inode->i_mapping;
+ index = outarg.offset >> PAGE_CACHE_SHIFT;
+ offset = outarg.offset & ~PAGE_CACHE_MASK;
+ file_size = i_size_read(inode);
+ end = outarg.offset + outarg.size;
+ if (end > file_size) {
+ file_size = end;
+ fuse_write_update_size(inode, file_size);
+ }
+
+ num = outarg.size;
+ while (num) {
+ struct page *page;
+ unsigned int this_num;
+
+ err = -ENOMEM;
+ page = find_or_create_page(mapping, index,
+ mapping_gfp_mask(mapping));
+ if (!page)
+ goto out_iput;
+
+ this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
+ err = fuse_copy_page(cs, &page, offset, this_num, 0);
+ if (!err && offset == 0 &&
+ (this_num == PAGE_CACHE_SIZE || file_size == end))
+ SetPageUptodate(page);
+ unlock_page(page);
+ page_cache_release(page);
+
+ if (err)
+ goto out_iput;
+
+ num -= this_num;
+ offset = 0;
+ index++;
+ }
+
+ err = 0;
+
+out_iput:
+ iput(inode);
+out_up_killsb:
+ up_read(&fc->killsb);
+out_finish:
+ fuse_copy_finish(cs);
+ return err;
+}
+
+static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
+{
+ release_pages(req->pages, req->num_pages, false);
+}
+
+static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
+ struct fuse_notify_retrieve_out *outarg)
+{
+ int err;
+ struct address_space *mapping = inode->i_mapping;
+ struct fuse_req *req;
+ pgoff_t index;
+ loff_t file_size;
+ unsigned int num;
+ unsigned int offset;
+ size_t total_len = 0;
+ int num_pages;
+
+ offset = outarg->offset & ~PAGE_CACHE_MASK;
+ file_size = i_size_read(inode);
+
+ num = outarg->size;
+ if (outarg->offset > file_size)
+ num = 0;
+ else if (outarg->offset + num > file_size)
+ num = file_size - outarg->offset;
+
+ num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
+
+ req = fuse_get_req(fc, num_pages);
+ if (IS_ERR(req))
+ return PTR_ERR(req);
+
+ req->in.h.opcode = FUSE_NOTIFY_REPLY;
+ req->in.h.nodeid = outarg->nodeid;
+ req->in.numargs = 2;
+ req->in.argpages = 1;
+ req->page_descs[0].offset = offset;
+ req->end = fuse_retrieve_end;
+
+ index = outarg->offset >> PAGE_CACHE_SHIFT;
+
+ while (num && req->num_pages < num_pages) {
+ struct page *page;
+ unsigned int this_num;
+
+ page = find_get_page(mapping, index);
+ if (!page)
+ break;
+
+ this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
+ req->pages[req->num_pages] = page;
+ req->page_descs[req->num_pages].length = this_num;
+ req->num_pages++;
+
+ offset = 0;
+ num -= this_num;
+ total_len += this_num;
+ index++;
+ }
+ req->misc.retrieve_in.offset = outarg->offset;
+ req->misc.retrieve_in.size = total_len;
+ req->in.args[0].size = sizeof(req->misc.retrieve_in);
+ req->in.args[0].value = &req->misc.retrieve_in;
+ req->in.args[1].size = total_len;
+
+ err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
+ if (err)
+ fuse_retrieve_end(fc, req);
+
+ return err;
+}
+
+static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
+ struct fuse_copy_state *cs)
+{
+ struct fuse_notify_retrieve_out outarg;
+ struct inode *inode;
+ int err;
+
+ err = -EINVAL;
+ if (size != sizeof(outarg))
+ goto copy_finish;
+
+ err = fuse_copy_one(cs, &outarg, sizeof(outarg));
+ if (err)
+ goto copy_finish;
+
+ fuse_copy_finish(cs);
+
+ down_read(&fc->killsb);
+ err = -ENOENT;
+ if (fc->sb) {
+ u64 nodeid = outarg.nodeid;
+
+ inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
+ if (inode) {
+ err = fuse_retrieve(fc, inode, &outarg);
+ iput(inode);
+ }
+ }
+ up_read(&fc->killsb);
+
+ return err;
+
+copy_finish:
+ fuse_copy_finish(cs);
+ return err;
+}
+
+static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
+ unsigned int size, struct fuse_copy_state *cs)
+{
+ /* Don't try to move pages (yet) */
+ cs->move_pages = 0;
+
+ switch (code) {
+ case FUSE_NOTIFY_POLL:
+ return fuse_notify_poll(fc, size, cs);
+
+ case FUSE_NOTIFY_INVAL_INODE:
+ return fuse_notify_inval_inode(fc, size, cs);
+
+ case FUSE_NOTIFY_INVAL_ENTRY:
+ return fuse_notify_inval_entry(fc, size, cs);
+
+ case FUSE_NOTIFY_STORE:
+ return fuse_notify_store(fc, size, cs);
+
+ case FUSE_NOTIFY_RETRIEVE:
+ return fuse_notify_retrieve(fc, size, cs);
+
+ case FUSE_NOTIFY_DELETE:
+ return fuse_notify_delete(fc, size, cs);
+
+ default:
+ fuse_copy_finish(cs);
+ return -EINVAL;
+ }
+}
+
+/* Look up request on processing list by unique ID */
+static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
+{
+ struct fuse_req *req;
+
+ list_for_each_entry(req, &fc->processing, list) {
+ if (req->in.h.unique == unique || req->intr_unique == unique)
+ return req;
+ }
+ return NULL;
+}
+
+static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
+ unsigned nbytes)
+{
+ unsigned reqsize = sizeof(struct fuse_out_header);
+
+ if (out->h.error)
+ return nbytes != reqsize ? -EINVAL : 0;
+
+ reqsize += len_args(out->numargs, out->args);
+
+ if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
+ return -EINVAL;
+ else if (reqsize > nbytes) {
+ struct fuse_arg *lastarg = &out->args[out->numargs-1];
+ unsigned diffsize = reqsize - nbytes;
+ if (diffsize > lastarg->size)
+ return -EINVAL;
+ lastarg->size -= diffsize;
+ }
+ return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
+ out->page_zeroing);
+}
+
+/*
+ * Write a single reply to a request. First the header is copied from
+ * the write buffer. The request is then searched on the processing
+ * list by the unique ID found in the header. If found, then remove
+ * it from the list and copy the rest of the buffer to the request.
+ * The request is finished by calling request_end()
+ */
+static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
+ struct fuse_copy_state *cs, size_t nbytes)
+{
+ int err;
+ struct fuse_req *req;
+ struct fuse_out_header oh;
+
+ if (nbytes < sizeof(struct fuse_out_header))
+ return -EINVAL;
+
+ err = fuse_copy_one(cs, &oh, sizeof(oh));
+ if (err)
+ goto err_finish;
+
+ err = -EINVAL;
+ if (oh.len != nbytes)
+ goto err_finish;
+
+ /*
+ * Zero oh.unique indicates unsolicited notification message
+ * and error contains notification code.
+ */
+ if (!oh.unique) {
+ err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
+ return err ? err : nbytes;
+ }
+
+ err = -EINVAL;
+ if (oh.error <= -1000 || oh.error > 0)
+ goto err_finish;
+
+ spin_lock(&fc->lock);
+ err = -ENOENT;
+ if (!fc->connected)
+ goto err_unlock;
+
+ req = request_find(fc, oh.unique);
+ if (!req)
+ goto err_unlock;
+
+ if (req->aborted) {
+ spin_unlock(&fc->lock);
+ fuse_copy_finish(cs);
+ spin_lock(&fc->lock);
+ request_end(fc, req);
+ return -ENOENT;
+ }
+ /* Is it an interrupt reply? */
+ if (req->intr_unique == oh.unique) {
+ err = -EINVAL;
+ if (nbytes != sizeof(struct fuse_out_header))
+ goto err_unlock;
+
+ if (oh.error == -ENOSYS)
+ fc->no_interrupt = 1;
+ else if (oh.error == -EAGAIN)
+ queue_interrupt(fc, req);
+
+ spin_unlock(&fc->lock);
+ fuse_copy_finish(cs);
+ return nbytes;
+ }
+
+ req->state = FUSE_REQ_WRITING;
+ list_move(&req->list, &fc->io);
+ req->out.h = oh;
+ req->locked = 1;
+ cs->req = req;
+ if (!req->out.page_replace)
+ cs->move_pages = 0;
+ spin_unlock(&fc->lock);
+
+ err = copy_out_args(cs, &req->out, nbytes);
+ fuse_copy_finish(cs);
+
+ spin_lock(&fc->lock);
+ req->locked = 0;
+ if (!err) {
+ if (req->aborted)
+ err = -ENOENT;
+ } else if (!req->aborted)
+ req->out.h.error = -EIO;
+ request_end(fc, req);
+
+ return err ? err : nbytes;
+
+ err_unlock:
+ spin_unlock(&fc->lock);
+ err_finish:
+ fuse_copy_finish(cs);
+ return err;
+}
+
+static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct fuse_copy_state cs;
+ struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
+ if (!fc)
+ return -EPERM;
+
+ if (!iter_is_iovec(from))
+ return -EINVAL;
+
+ fuse_copy_init(&cs, fc, 0, from);
+
+ return fuse_dev_do_write(fc, &cs, iov_iter_count(from));
+}
+
+static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
+ struct file *out, loff_t *ppos,
+ size_t len, unsigned int flags)
+{
+ unsigned nbuf;
+ unsigned idx;
+ struct pipe_buffer *bufs;
+ struct fuse_copy_state cs;
+ struct fuse_conn *fc;
+ size_t rem;
+ ssize_t ret;
+
+ fc = fuse_get_conn(out);
+ if (!fc)
+ return -EPERM;
+
+ bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
+ if (!bufs)
+ return -ENOMEM;
+
+ pipe_lock(pipe);
+ nbuf = 0;
+ rem = 0;
+ for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
+ rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
+
+ ret = -EINVAL;
+ if (rem < len) {
+ pipe_unlock(pipe);
+ goto out;
+ }
+
+ rem = len;
+ while (rem) {
+ struct pipe_buffer *ibuf;
+ struct pipe_buffer *obuf;
+
+ BUG_ON(nbuf >= pipe->buffers);
+ BUG_ON(!pipe->nrbufs);
+ ibuf = &pipe->bufs[pipe->curbuf];
+ obuf = &bufs[nbuf];
+
+ if (rem >= ibuf->len) {
+ *obuf = *ibuf;
+ ibuf->ops = NULL;
+ pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
+ pipe->nrbufs--;
+ } else {
+ ibuf->ops->get(pipe, ibuf);
+ *obuf = *ibuf;
+ obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
+ obuf->len = rem;
+ ibuf->offset += obuf->len;
+ ibuf->len -= obuf->len;
+ }
+ nbuf++;
+ rem -= obuf->len;
+ }
+ pipe_unlock(pipe);
+
+ fuse_copy_init(&cs, fc, 0, NULL);
+ cs.pipebufs = bufs;
+ cs.nr_segs = nbuf;
+ cs.pipe = pipe;
+
+ if (flags & SPLICE_F_MOVE)
+ cs.move_pages = 1;
+
+ ret = fuse_dev_do_write(fc, &cs, len);
+
+ for (idx = 0; idx < nbuf; idx++) {
+ struct pipe_buffer *buf = &bufs[idx];
+ buf->ops->release(pipe, buf);
+ }
+out:
+ kfree(bufs);
+ return ret;
+}
+
+static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
+{
+ unsigned mask = POLLOUT | POLLWRNORM;
+ struct fuse_conn *fc = fuse_get_conn(file);
+ if (!fc)
+ return POLLERR;
+
+ poll_wait(file, &fc->waitq, wait);
+
+ spin_lock(&fc->lock);
+ if (!fc->connected)
+ mask = POLLERR;
+ else if (request_pending(fc))
+ mask |= POLLIN | POLLRDNORM;
+ spin_unlock(&fc->lock);
+
+ return mask;
+}
+
+/*
+ * Abort all requests on the given list (pending or processing)
+ *
+ * This function releases and reacquires fc->lock
+ */
+static void end_requests(struct fuse_conn *fc, struct list_head *head)
+__releases(fc->lock)
+__acquires(fc->lock)
+{
+ while (!list_empty(head)) {
+ struct fuse_req *req;
+ req = list_entry(head->next, struct fuse_req, list);
+ req->out.h.error = -ECONNABORTED;
+ request_end(fc, req);
+ spin_lock(&fc->lock);
+ }
+}
+
+/*
+ * Abort requests under I/O
+ *
+ * The requests are set to aborted and finished, and the request
+ * waiter is woken up. This will make request_wait_answer() wait
+ * until the request is unlocked and then return.
+ *
+ * If the request is asynchronous, then the end function needs to be
+ * called after waiting for the request to be unlocked (if it was
+ * locked).
+ */
+static void end_io_requests(struct fuse_conn *fc)
+__releases(fc->lock)
+__acquires(fc->lock)
+{
+ while (!list_empty(&fc->io)) {
+ struct fuse_req *req =
+ list_entry(fc->io.next, struct fuse_req, list);
+ void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
+
+ req->aborted = 1;
+ req->out.h.error = -ECONNABORTED;
+ req->state = FUSE_REQ_FINISHED;
+ list_del_init(&req->list);
+ wake_up(&req->waitq);
+ if (end) {
+ req->end = NULL;
+ __fuse_get_request(req);
+ spin_unlock(&fc->lock);
+ wait_event(req->waitq, !req->locked);
+ end(fc, req);
+ fuse_put_request(fc, req);
+ spin_lock(&fc->lock);
+ }
+ }
+}
+
+static void end_queued_requests(struct fuse_conn *fc)
+__releases(fc->lock)
+__acquires(fc->lock)
+{
+ fc->max_background = UINT_MAX;
+ flush_bg_queue(fc);
+ end_requests(fc, &fc->pending);
+ end_requests(fc, &fc->processing);
+ while (forget_pending(fc))
+ kfree(dequeue_forget(fc, 1, NULL));
+}
+
+static void end_polls(struct fuse_conn *fc)
+{
+ struct rb_node *p;
+
+ p = rb_first(&fc->polled_files);
+
+ while (p) {
+ struct fuse_file *ff;
+ ff = rb_entry(p, struct fuse_file, polled_node);
+ wake_up_interruptible_all(&ff->poll_wait);
+
+ p = rb_next(p);
+ }
+}
+
+/*
+ * Abort all requests.
+ *
+ * Emergency exit in case of a malicious or accidental deadlock, or
+ * just a hung filesystem.
+ *
+ * The same effect is usually achievable through killing the
+ * filesystem daemon and all users of the filesystem. The exception
+ * is the combination of an asynchronous request and the tricky
+ * deadlock (see Documentation/filesystems/fuse.txt).
+ *
+ * During the aborting, progression of requests from the pending and
+ * processing lists onto the io list, and progression of new requests
+ * onto the pending list is prevented by req->connected being false.
+ *
+ * Progression of requests under I/O to the processing list is
+ * prevented by the req->aborted flag being true for these requests.
+ * For this reason requests on the io list must be aborted first.
+ */
+void fuse_abort_conn(struct fuse_conn *fc)
+{
+ spin_lock(&fc->lock);
+ if (fc->connected) {
+ fc->connected = 0;
+ fc->blocked = 0;
+ fuse_set_initialized(fc);
+ end_io_requests(fc);
+ end_queued_requests(fc);
+ end_polls(fc);
+ wake_up_all(&fc->waitq);
+ wake_up_all(&fc->blocked_waitq);
+ kill_fasync(&fc->fasync, SIGIO, POLL_IN);
+ }
+ spin_unlock(&fc->lock);
+}
+EXPORT_SYMBOL_GPL(fuse_abort_conn);
+
+int fuse_dev_release(struct inode *inode, struct file *file)
+{
+ struct fuse_conn *fc = fuse_get_conn(file);
+ if (fc) {
+ spin_lock(&fc->lock);
+ fc->connected = 0;
+ fc->blocked = 0;
+ fuse_set_initialized(fc);
+ end_queued_requests(fc);
+ end_polls(fc);
+ wake_up_all(&fc->blocked_waitq);
+ spin_unlock(&fc->lock);
+ fuse_conn_put(fc);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fuse_dev_release);
+
+static int fuse_dev_fasync(int fd, struct file *file, int on)
+{
+ struct fuse_conn *fc = fuse_get_conn(file);
+ if (!fc)
+ return -EPERM;
+
+ /* No locking - fasync_helper does its own locking */
+ return fasync_helper(fd, file, on, &fc->fasync);
+}
+
+const struct file_operations fuse_dev_operations = {
+ .owner = THIS_MODULE,
+ .open = fuse_dev_open,
+ .llseek = no_llseek,
+ .read_iter = fuse_dev_read,
+ .splice_read = fuse_dev_splice_read,
+ .write_iter = fuse_dev_write,
+ .splice_write = fuse_dev_splice_write,
+ .poll = fuse_dev_poll,
+ .release = fuse_dev_release,
+ .fasync = fuse_dev_fasync,
+};
+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);
+}
Code Review / kvmfornfv.git / blobdiff