--- /dev/null
+/*
+ FUSE: Filesystem in Userspace
+ Copyright (C) 2001-2006 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>
+
+MODULE_ALIAS_MISCDEV(FUSE_MINOR);
+
+static kmem_cache_t *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)
+{
+ memset(req, 0, sizeof(*req));
+ INIT_LIST_HEAD(&req->list);
+ init_waitqueue_head(&req->waitq);
+ atomic_set(&req->count, 1);
+}
+
+struct fuse_req *fuse_request_alloc(void)
+{
+ struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, SLAB_KERNEL);
+ if (req)
+ fuse_request_init(req);
+ return req;
+}
+
+void fuse_request_free(struct fuse_req *req)
+{
+ 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);
+}
+
+/*
+ * Reset request, so that it can be reused
+ *
+ * The caller must be _very_ careful to make sure, that it is holding
+ * the only reference to req
+ */
+void fuse_reset_request(struct fuse_req *req)
+{
+ BUG_ON(atomic_read(&req->count) != 1);
+ fuse_request_init(req);
+}
+
+static 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);
+}
+
+struct fuse_req *fuse_get_req(struct fuse_conn *fc)
+{
+ struct fuse_req *req;
+ sigset_t oldset;
+ int intr;
+ int err;
+
+ atomic_inc(&fc->num_waiting);
+ block_sigs(&oldset);
+ intr = wait_event_interruptible(fc->blocked_waitq, !fc->blocked);
+ restore_sigs(&oldset);
+ err = -EINTR;
+ if (intr)
+ goto out;
+
+ req = fuse_request_alloc();
+ err = -ENOMEM;
+ if (!req)
+ goto out;
+
+ req->in.h.uid = current->fsuid;
+ req->in.h.gid = current->fsgid;
+ req->in.h.pid = current->pid;
+ req->waiting = 1;
+ return req;
+
+ out:
+ atomic_dec(&fc->num_waiting);
+ return ERR_PTR(err);
+}
+
+void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
+{
+ if (atomic_dec_and_test(&req->count)) {
+ if (req->waiting)
+ atomic_dec(&fc->num_waiting);
+ fuse_request_free(req);
+ }
+}
+
+/*
+ * Called with sbput_sem held for read (request_end) or write
+ * (fuse_put_super). By the time fuse_put_super() is finished, all
+ * inodes belonging to background requests must be released, so the
+ * iputs have to be done within the locked region.
+ */
+void fuse_release_background(struct fuse_conn *fc, struct fuse_req *req)
+{
+ iput(req->inode);
+ iput(req->inode2);
+ spin_lock(&fc->lock);
+ list_del(&req->bg_entry);
+ if (fc->num_background == FUSE_MAX_BACKGROUND) {
+ fc->blocked = 0;
+ wake_up_all(&fc->blocked_waitq);
+ }
+ fc->num_background--;
+ spin_unlock(&fc->lock);
+}
+
+/*
+ * This function is called when a request is finished. Either a reply
+ * has arrived or it was interrupted (and not yet sent) or some error
+ * occurred during communication with userspace, or the device file
+ * was closed. In case of a background request the reference to the
+ * stored objects are released. The requester thread is woken up (if
+ * still waiting), the 'end' callback is called if given, else the
+ * reference to the request is released
+ *
+ * Releasing extra reference for foreground requests must be done
+ * within the same locked region as setting state to finished. This
+ * is because fuse_reset_request() may be called after request is
+ * finished and it must be the sole possessor. If request is
+ * interrupted and put in the background, it will return with an error
+ * and hence never be reset and reused.
+ *
+ * Called with fc->lock, unlocks it
+ */
+static void request_end(struct fuse_conn *fc, struct fuse_req *req)
+{
+ list_del(&req->list);
+ req->state = FUSE_REQ_FINISHED;
+ if (!req->background) {
+ spin_unlock(&fc->lock);
+ wake_up(&req->waitq);
+ fuse_put_request(fc, req);
+ } else {
+ void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
+ req->end = NULL;
+ spin_unlock(&fc->lock);
+ down_read(&fc->sbput_sem);
+ if (fc->mounted)
+ fuse_release_background(fc, req);
+ up_read(&fc->sbput_sem);
+
+ /* fput must go outside sbput_sem, otherwise it can deadlock */
+ if (req->file)
+ fput(req->file);
+
+ if (end)
+ end(fc, req);
+ else
+ fuse_put_request(fc, req);
+ }
+}
+
+/*
+ * Unfortunately request interruption not just solves the deadlock
+ * problem, it causes problems too. These stem from the fact, that an
+ * interrupted request is continued to be processed in userspace,
+ * while all the locks and object references (inode and file) held
+ * during the operation are released.
+ *
+ * To release the locks is exactly why there's a need to interrupt the
+ * request, so there's not a lot that can be done about this, except
+ * introduce additional locking in userspace.
+ *
+ * More important is to keep inode and file references until userspace
+ * has replied, otherwise FORGET and RELEASE could be sent while the
+ * inode/file is still used by the filesystem.
+ *
+ * For this reason the concept of "background" request is introduced.
+ * An interrupted request is backgrounded if it has been already sent
+ * to userspace. Backgrounding involves getting an extra reference to
+ * inode(s) or file used in the request, and adding the request to
+ * fc->background list. When a reply is received for a background
+ * request, the object references are released, and the request is
+ * removed from the list. If the filesystem is unmounted while there
+ * are still background requests, the list is walked and references
+ * are released as if a reply was received.
+ *
+ * There's one more use for a background request. The RELEASE message is
+ * always sent as background, since it doesn't return an error or
+ * data.
+ */
+static void background_request(struct fuse_conn *fc, struct fuse_req *req)
+{
+ req->background = 1;
+ list_add(&req->bg_entry, &fc->background);
+ fc->num_background++;
+ if (fc->num_background == FUSE_MAX_BACKGROUND)
+ fc->blocked = 1;
+ if (req->inode)
+ req->inode = igrab(req->inode);
+ if (req->inode2)
+ req->inode2 = igrab(req->inode2);
+ if (req->file)
+ get_file(req->file);
+}
+
+/* Called with fc->lock held. Releases, and then reacquires it. */
+static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
+{
+ sigset_t oldset;
+
+ spin_unlock(&fc->lock);
+ block_sigs(&oldset);
+ wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
+ restore_sigs(&oldset);
+ spin_lock(&fc->lock);
+ if (req->state == FUSE_REQ_FINISHED && !req->interrupted)
+ return;
+
+ if (!req->interrupted) {
+ req->out.h.error = -EINTR;
+ req->interrupted = 1;
+ }
+ 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);
+ }
+ if (req->state == FUSE_REQ_PENDING) {
+ list_del(&req->list);
+ __fuse_put_request(req);
+ } else if (req->state == FUSE_REQ_SENT)
+ background_request(fc, req);
+}
+
+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 void queue_request(struct fuse_conn *fc, struct fuse_req *req)
+{
+ fc->reqctr++;
+ /* zero is special */
+ if (fc->reqctr == 0)
+ fc->reqctr = 1;
+ req->in.h.unique = fc->reqctr;
+ 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);
+}
+
+/*
+ * This can only be interrupted by a SIGKILL
+ */
+void request_send(struct fuse_conn *fc, struct fuse_req *req)
+{
+ req->isreply = 1;
+ spin_lock(&fc->lock);
+ if (!fc->connected)
+ req->out.h.error = -ENOTCONN;
+ else if (fc->conn_error)
+ req->out.h.error = -ECONNREFUSED;
+ else {
+ 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);
+}
+
+static void request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
+{
+ spin_lock(&fc->lock);
+ background_request(fc, req);
+ if (fc->connected) {
+ queue_request(fc, req);
+ spin_unlock(&fc->lock);
+ } else {
+ req->out.h.error = -ENOTCONN;
+ request_end(fc, req);
+ }
+}
+
+void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req)
+{
+ req->isreply = 0;
+ request_send_nowait(fc, req);
+}
+
+void request_send_background(struct fuse_conn *fc, struct fuse_req *req)
+{
+ req->isreply = 1;
+ request_send_nowait(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
+ * interrupted 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->interrupted)
+ err = -ENOENT;
+ else
+ req->locked = 1;
+ spin_unlock(&fc->lock);
+ }
+ return err;
+}
+
+/*
+ * Unlock request. If it was interrupted 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->interrupted)
+ wake_up(&req->waitq);
+ spin_unlock(&fc->lock);
+ }
+}
+
+struct fuse_copy_state {
+ struct fuse_conn *fc;
+ int write;
+ struct fuse_req *req;
+ const struct iovec *iov;
+ unsigned long nr_segs;
+ unsigned long seglen;
+ unsigned long addr;
+ struct page *pg;
+ void *mapaddr;
+ void *buf;
+ unsigned len;
+};
+
+static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc,
+ int write, struct fuse_req *req,
+ const struct iovec *iov, unsigned long nr_segs)
+{
+ memset(cs, 0, sizeof(*cs));
+ cs->fc = fc;
+ cs->write = write;
+ cs->req = req;
+ cs->iov = iov;
+ cs->nr_segs = nr_segs;
+}
+
+/* Unmap and put previous page of userspace buffer */
+static void fuse_copy_finish(struct fuse_copy_state *cs)
+{
+ if (cs->mapaddr) {
+ kunmap_atomic(cs->mapaddr, KM_USER0);
+ if (cs->write) {
+ flush_dcache_page(cs->pg);
+ set_page_dirty_lock(cs->pg);
+ }
+ put_page(cs->pg);
+ cs->mapaddr = 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)
+{
+ unsigned long offset;
+ int err;
+
+ unlock_request(cs->fc, cs->req);
+ fuse_copy_finish(cs);
+ if (!cs->seglen) {
+ BUG_ON(!cs->nr_segs);
+ cs->seglen = cs->iov[0].iov_len;
+ cs->addr = (unsigned long) cs->iov[0].iov_base;
+ cs->iov ++;
+ cs->nr_segs --;
+ }
+ down_read(¤t->mm->mmap_sem);
+ err = get_user_pages(current, current->mm, cs->addr, 1, cs->write, 0,
+ &cs->pg, NULL);
+ up_read(¤t->mm->mmap_sem);
+ if (err < 0)
+ return err;
+ BUG_ON(err != 1);
+ offset = cs->addr % PAGE_SIZE;
+ cs->mapaddr = kmap_atomic(cs->pg, KM_USER0);
+ cs->buf = cs->mapaddr + offset;
+ cs->len = min(PAGE_SIZE - offset, cs->seglen);
+ cs->seglen -= cs->len;
+ cs->addr += cs->len;
+
+ 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) {
+ if (cs->write)
+ memcpy(cs->buf, *val, ncpy);
+ else
+ memcpy(*val, cs->buf, ncpy);
+ *val += ncpy;
+ }
+ *size -= ncpy;
+ cs->len -= ncpy;
+ cs->buf += ncpy;
+ return ncpy;
+}
+
+/*
+ * 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 *page,
+ unsigned offset, unsigned count, int zeroing)
+{
+ if (page && zeroing && count < PAGE_SIZE) {
+ void *mapaddr = kmap_atomic(page, KM_USER1);
+ memset(mapaddr, 0, PAGE_SIZE);
+ kunmap_atomic(mapaddr, KM_USER1);
+ }
+ while (count) {
+ int err;
+ if (!cs->len && (err = fuse_copy_fill(cs)))
+ return err;
+ if (page) {
+ void *mapaddr = kmap_atomic(page, KM_USER1);
+ void *buf = mapaddr + offset;
+ offset += fuse_copy_do(cs, &buf, &count);
+ kunmap_atomic(mapaddr, KM_USER1);
+ } 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;
+ unsigned offset = req->page_offset;
+ unsigned count = min(nbytes, (unsigned) PAGE_SIZE - offset);
+
+ for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
+ struct page *page = req->pages[i];
+ int err = fuse_copy_page(cs, page, offset, count, zeroing);
+ if (err)
+ return err;
+
+ nbytes -= count;
+ count = min(nbytes, (unsigned) PAGE_SIZE);
+ offset = 0;
+ }
+ 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) {
+ int err;
+ if (!cs->len && (err = fuse_copy_fill(cs)))
+ 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;
+}
+
+/* Wait until a request is available on the pending list */
+static void request_wait(struct fuse_conn *fc)
+{
+ DECLARE_WAITQUEUE(wait, current);
+
+ add_wait_queue_exclusive(&fc->waitq, &wait);
+ while (fc->connected && list_empty(&fc->pending)) {
+ 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);
+}
+
+/*
+ * 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 interrupted 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_readv(struct file *file, const struct iovec *iov,
+ unsigned long nr_segs, loff_t *off)
+{
+ int err;
+ struct fuse_req *req;
+ struct fuse_in *in;
+ struct fuse_copy_state cs;
+ unsigned reqsize;
+ struct fuse_conn *fc = fuse_get_conn(file);
+ if (!fc)
+ return -EPERM;
+
+ restart:
+ spin_lock(&fc->lock);
+ err = -EAGAIN;
+ if ((file->f_flags & O_NONBLOCK) && fc->connected &&
+ list_empty(&fc->pending))
+ goto err_unlock;
+
+ request_wait(fc);
+ err = -ENODEV;
+ if (!fc->connected)
+ goto err_unlock;
+ err = -ERESTARTSYS;
+ if (list_empty(&fc->pending))
+ goto err_unlock;
+
+ 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 (iov_length(iov, nr_segs) < 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);
+ fuse_copy_init(&cs, fc, 1, req, iov, nr_segs);
+ 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 (!err && req->interrupted)
+ err = -ENOENT;
+ if (err) {
+ if (!req->interrupted)
+ 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);
+ spin_unlock(&fc->lock);
+ }
+ return reqsize;
+
+ err_unlock:
+ spin_unlock(&fc->lock);
+ return err;
+}
+
+static ssize_t fuse_dev_read(struct file *file, char __user *buf,
+ size_t nbytes, loff_t *off)
+{
+ struct iovec iov;
+ iov.iov_len = nbytes;
+ iov.iov_base = buf;
+ return fuse_dev_readv(file, &iov, 1, off);
+}
+
+/* Look up request on processing list by unique ID */
+static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
+{
+ struct list_head *entry;
+
+ list_for_each(entry, &fc->processing) {
+ struct fuse_req *req;
+ req = list_entry(entry, struct fuse_req, list);
+ if (req->in.h.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_writev(struct file *file, const struct iovec *iov,
+ unsigned long nr_segs, loff_t *off)
+{
+ int err;
+ unsigned nbytes = iov_length(iov, nr_segs);
+ struct fuse_req *req;
+ struct fuse_out_header oh;
+ struct fuse_copy_state cs;
+ struct fuse_conn *fc = fuse_get_conn(file);
+ if (!fc)
+ return -EPERM;
+
+ fuse_copy_init(&cs, fc, 0, NULL, iov, nr_segs);
+ 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.unique || oh.error <= -1000 || oh.error > 0 ||
+ oh.len != nbytes)
+ goto err_finish;
+
+ spin_lock(&fc->lock);
+ err = -ENOENT;
+ if (!fc->connected)
+ goto err_unlock;
+
+ req = request_find(fc, oh.unique);
+ err = -EINVAL;
+ if (!req)
+ goto err_unlock;
+
+ if (req->interrupted) {
+ spin_unlock(&fc->lock);
+ fuse_copy_finish(&cs);
+ spin_lock(&fc->lock);
+ request_end(fc, req);
+ return -ENOENT;
+ }
+ list_move(&req->list, &fc->io);
+ req->out.h = oh;
+ req->locked = 1;
+ cs.req = req;
+ 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->interrupted)
+ err = -ENOENT;
+ } else if (!req->interrupted)
+ 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 file *file, const char __user *buf,
+ size_t nbytes, loff_t *off)
+{
+ struct iovec iov;
+ iov.iov_len = nbytes;
+ iov.iov_base = (char __user *) buf;
+ return fuse_dev_writev(file, &iov, 1, off);
+}
+
+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 (!list_empty(&fc->pending))
+ 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)
+{
+ 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 interrupted 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)
+{
+ 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->interrupted = 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;
+ /* The end function will consume this reference */
+ __fuse_get_request(req);
+ spin_unlock(&fc->lock);
+ wait_event(req->waitq, !req->locked);
+ end(fc, req);
+ spin_lock(&fc->lock);
+ }
+ }
+}
+
+/*
+ * 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->interrupted 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;
+ end_io_requests(fc);
+ end_requests(fc, &fc->pending);
+ end_requests(fc, &fc->processing);
+ wake_up_all(&fc->waitq);
+ kill_fasync(&fc->fasync, SIGIO, POLL_IN);
+ }
+ spin_unlock(&fc->lock);
+}
+
+static 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;
+ end_requests(fc, &fc->pending);
+ end_requests(fc, &fc->processing);
+ spin_unlock(&fc->lock);
+ fasync_helper(-1, file, 0, &fc->fasync);
+ kobject_put(&fc->kobj);
+ }
+
+ return 0;
+}
+
+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,
+ .llseek = no_llseek,
+ .read = fuse_dev_read,
+ .readv = fuse_dev_readv,
+ .write = fuse_dev_write,
+ .writev = fuse_dev_writev,
+ .poll = fuse_dev_poll,
+ .release = fuse_dev_release,
+ .fasync = fuse_dev_fasync,
+};
+
+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, 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);
+}
git://git.onelab.eu / linux-2.6.git / blobdiff