2005-09-10 04:10:27 +08:00
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/*
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FUSE: Filesystem in Userspace
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Copyright (C) 2001-2005 Miklos Szeredi <miklos@szeredi.hu>
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This program can be distributed under the terms of the GNU GPL.
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See the file COPYING.
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*/
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#include "fuse_i.h"
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/poll.h>
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#include <linux/uio.h>
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#include <linux/miscdevice.h>
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#include <linux/pagemap.h>
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#include <linux/file.h>
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#include <linux/slab.h>
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MODULE_ALIAS_MISCDEV(FUSE_MINOR);
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static kmem_cache_t *fuse_req_cachep;
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2006-01-17 14:14:28 +08:00
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static struct fuse_conn *fuse_get_conn(struct file *file)
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2005-09-10 04:10:27 +08:00
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{
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struct fuse_conn *fc;
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spin_lock(&fuse_lock);
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fc = file->private_data;
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2006-01-17 14:14:34 +08:00
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if (fc && !fc->connected)
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2005-09-10 04:10:27 +08:00
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fc = NULL;
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spin_unlock(&fuse_lock);
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return fc;
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}
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2006-01-17 14:14:28 +08:00
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static void fuse_request_init(struct fuse_req *req)
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2005-09-10 04:10:27 +08:00
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{
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memset(req, 0, sizeof(*req));
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INIT_LIST_HEAD(&req->list);
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init_waitqueue_head(&req->waitq);
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atomic_set(&req->count, 1);
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}
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struct fuse_req *fuse_request_alloc(void)
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{
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struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, SLAB_KERNEL);
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if (req)
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fuse_request_init(req);
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return req;
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}
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void fuse_request_free(struct fuse_req *req)
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{
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kmem_cache_free(fuse_req_cachep, req);
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}
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2006-01-17 14:14:28 +08:00
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static void block_sigs(sigset_t *oldset)
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2005-09-10 04:10:27 +08:00
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{
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sigset_t mask;
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siginitsetinv(&mask, sigmask(SIGKILL));
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sigprocmask(SIG_BLOCK, &mask, oldset);
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}
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2006-01-17 14:14:28 +08:00
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static void restore_sigs(sigset_t *oldset)
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2005-09-10 04:10:27 +08:00
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{
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sigprocmask(SIG_SETMASK, oldset, NULL);
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}
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2006-02-18 05:52:52 +08:00
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/*
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* Reset request, so that it can be reused
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*
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* The caller must be _very_ careful to make sure, that it is holding
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* the only reference to req
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*/
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2005-09-10 04:10:27 +08:00
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void fuse_reset_request(struct fuse_req *req)
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{
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int preallocated = req->preallocated;
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BUG_ON(atomic_read(&req->count) != 1);
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fuse_request_init(req);
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req->preallocated = preallocated;
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}
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static void __fuse_get_request(struct fuse_req *req)
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{
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atomic_inc(&req->count);
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}
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/* Must be called with > 1 refcount */
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static void __fuse_put_request(struct fuse_req *req)
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{
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BUG_ON(atomic_read(&req->count) < 2);
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atomic_dec(&req->count);
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}
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static struct fuse_req *do_get_request(struct fuse_conn *fc)
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{
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struct fuse_req *req;
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spin_lock(&fuse_lock);
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BUG_ON(list_empty(&fc->unused_list));
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req = list_entry(fc->unused_list.next, struct fuse_req, list);
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list_del_init(&req->list);
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spin_unlock(&fuse_lock);
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fuse_request_init(req);
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req->preallocated = 1;
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req->in.h.uid = current->fsuid;
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req->in.h.gid = current->fsgid;
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req->in.h.pid = current->pid;
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return req;
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}
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2005-09-10 04:10:39 +08:00
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/* This can return NULL, but only in case it's interrupted by a SIGKILL */
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2005-09-10 04:10:27 +08:00
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struct fuse_req *fuse_get_request(struct fuse_conn *fc)
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{
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int intr;
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sigset_t oldset;
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2006-01-17 14:14:38 +08:00
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atomic_inc(&fc->num_waiting);
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2005-09-10 04:10:27 +08:00
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block_sigs(&oldset);
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intr = down_interruptible(&fc->outstanding_sem);
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restore_sigs(&oldset);
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2006-01-17 14:14:38 +08:00
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if (intr) {
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atomic_dec(&fc->num_waiting);
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return NULL;
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}
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return do_get_request(fc);
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2005-09-10 04:10:27 +08:00
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}
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2006-02-05 15:27:40 +08:00
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/* Must be called with fuse_lock held */
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2005-09-10 04:10:27 +08:00
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static void fuse_putback_request(struct fuse_conn *fc, struct fuse_req *req)
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{
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2006-01-17 14:14:38 +08:00
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if (req->preallocated) {
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atomic_dec(&fc->num_waiting);
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2005-09-10 04:10:27 +08:00
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list_add(&req->list, &fc->unused_list);
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2006-01-17 14:14:38 +08:00
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} else
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2005-09-10 04:10:27 +08:00
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fuse_request_free(req);
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/* If we are in debt decrease that first */
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if (fc->outstanding_debt)
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fc->outstanding_debt--;
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else
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up(&fc->outstanding_sem);
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}
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void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
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2006-02-05 15:27:40 +08:00
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{
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if (atomic_dec_and_test(&req->count)) {
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spin_lock(&fuse_lock);
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fuse_putback_request(fc, req);
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spin_unlock(&fuse_lock);
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}
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}
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static void fuse_put_request_locked(struct fuse_conn *fc, struct fuse_req *req)
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2005-09-10 04:10:27 +08:00
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{
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if (atomic_dec_and_test(&req->count))
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fuse_putback_request(fc, req);
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}
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2005-09-10 04:10:31 +08:00
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void fuse_release_background(struct fuse_req *req)
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{
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iput(req->inode);
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iput(req->inode2);
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if (req->file)
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fput(req->file);
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spin_lock(&fuse_lock);
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list_del(&req->bg_entry);
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spin_unlock(&fuse_lock);
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}
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2005-09-10 04:10:27 +08:00
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/*
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* This function is called when a request is finished. Either a reply
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* has arrived or it was interrupted (and not yet sent) or some error
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2006-01-17 14:14:26 +08:00
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* occurred during communication with userspace, or the device file
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* was closed. In case of a background request the reference to the
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* stored objects are released. The requester thread is woken up (if
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2006-01-17 14:14:42 +08:00
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* still waiting), the 'end' callback is called if given, else the
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* reference to the request is released
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2005-09-10 04:10:27 +08:00
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*
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2006-02-05 15:27:40 +08:00
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* Releasing extra reference for foreground requests must be done
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* within the same locked region as setting state to finished. This
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* is because fuse_reset_request() may be called after request is
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* finished and it must be the sole possessor. If request is
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* interrupted and put in the background, it will return with an error
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* and hence never be reset and reused.
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*
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2005-09-10 04:10:27 +08:00
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* Called with fuse_lock, unlocks it
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*/
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static void request_end(struct fuse_conn *fc, struct fuse_req *req)
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{
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2006-01-17 14:14:31 +08:00
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list_del(&req->list);
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2006-01-17 14:14:31 +08:00
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req->state = FUSE_REQ_FINISHED;
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2006-02-05 15:27:40 +08:00
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if (!req->background) {
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wake_up(&req->waitq);
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fuse_put_request_locked(fc, req);
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spin_unlock(&fuse_lock);
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} else {
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void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
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req->end = NULL;
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spin_unlock(&fuse_lock);
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2005-09-10 04:10:31 +08:00
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down_read(&fc->sbput_sem);
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if (fc->mounted)
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fuse_release_background(req);
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up_read(&fc->sbput_sem);
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2006-02-05 15:27:40 +08:00
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if (end)
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end(fc, req);
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else
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fuse_put_request(fc, req);
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2005-09-10 04:10:27 +08:00
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}
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}
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2005-09-10 04:10:31 +08:00
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/*
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* Unfortunately request interruption not just solves the deadlock
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* problem, it causes problems too. These stem from the fact, that an
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* interrupted request is continued to be processed in userspace,
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* while all the locks and object references (inode and file) held
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* during the operation are released.
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*
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* To release the locks is exactly why there's a need to interrupt the
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* request, so there's not a lot that can be done about this, except
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* introduce additional locking in userspace.
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*
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* More important is to keep inode and file references until userspace
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* has replied, otherwise FORGET and RELEASE could be sent while the
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* inode/file is still used by the filesystem.
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*
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* For this reason the concept of "background" request is introduced.
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* An interrupted request is backgrounded if it has been already sent
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* to userspace. Backgrounding involves getting an extra reference to
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* inode(s) or file used in the request, and adding the request to
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* fc->background list. When a reply is received for a background
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* request, the object references are released, and the request is
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* removed from the list. If the filesystem is unmounted while there
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* are still background requests, the list is walked and references
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* are released as if a reply was received.
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*
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* There's one more use for a background request. The RELEASE message is
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* always sent as background, since it doesn't return an error or
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* data.
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*/
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static void background_request(struct fuse_conn *fc, struct fuse_req *req)
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2005-09-10 04:10:27 +08:00
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{
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req->background = 1;
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2005-09-10 04:10:31 +08:00
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list_add(&req->bg_entry, &fc->background);
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2005-09-10 04:10:27 +08:00
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if (req->inode)
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req->inode = igrab(req->inode);
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if (req->inode2)
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req->inode2 = igrab(req->inode2);
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if (req->file)
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get_file(req->file);
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}
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/* Called with fuse_lock held. Releases, and then reacquires it. */
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2005-09-10 04:10:39 +08:00
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static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
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2005-09-10 04:10:27 +08:00
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{
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2005-09-10 04:10:39 +08:00
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sigset_t oldset;
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2005-09-10 04:10:27 +08:00
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spin_unlock(&fuse_lock);
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2005-09-10 04:10:39 +08:00
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block_sigs(&oldset);
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2006-01-17 14:14:31 +08:00
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wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
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2005-09-10 04:10:39 +08:00
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restore_sigs(&oldset);
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2005-09-10 04:10:27 +08:00
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spin_lock(&fuse_lock);
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2006-01-17 14:14:41 +08:00
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if (req->state == FUSE_REQ_FINISHED && !req->interrupted)
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2005-09-10 04:10:27 +08:00
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return;
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2006-01-17 14:14:41 +08:00
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if (!req->interrupted) {
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req->out.h.error = -EINTR;
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req->interrupted = 1;
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}
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2005-09-10 04:10:27 +08:00
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if (req->locked) {
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/* This is uninterruptible sleep, because data is
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being copied to/from the buffers of req. During
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locked state, there mustn't be any filesystem
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operation (e.g. page fault), since that could lead
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to deadlock */
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spin_unlock(&fuse_lock);
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wait_event(req->waitq, !req->locked);
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spin_lock(&fuse_lock);
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}
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2006-01-17 14:14:31 +08:00
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if (req->state == FUSE_REQ_PENDING) {
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2005-09-10 04:10:27 +08:00
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list_del(&req->list);
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__fuse_put_request(req);
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2006-01-17 14:14:31 +08:00
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} else if (req->state == FUSE_REQ_SENT)
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2005-09-10 04:10:31 +08:00
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background_request(fc, req);
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2005-09-10 04:10:27 +08:00
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}
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static unsigned len_args(unsigned numargs, struct fuse_arg *args)
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{
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unsigned nbytes = 0;
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unsigned i;
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for (i = 0; i < numargs; i++)
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nbytes += args[i].size;
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return nbytes;
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}
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static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
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{
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fc->reqctr++;
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/* zero is special */
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if (fc->reqctr == 0)
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fc->reqctr = 1;
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req->in.h.unique = fc->reqctr;
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req->in.h.len = sizeof(struct fuse_in_header) +
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len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
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if (!req->preallocated) {
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/* If request is not preallocated (either FORGET or
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RELEASE), then still decrease outstanding_sem, so
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user can't open infinite number of files while not
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processing the RELEASE requests. However for
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efficiency do it without blocking, so if down()
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would block, just increase the debt instead */
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if (down_trylock(&fc->outstanding_sem))
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fc->outstanding_debt++;
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}
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list_add_tail(&req->list, &fc->pending);
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2006-01-17 14:14:31 +08:00
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req->state = FUSE_REQ_PENDING;
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2005-09-10 04:10:27 +08:00
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wake_up(&fc->waitq);
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}
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2005-09-10 04:10:39 +08:00
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/*
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* This can only be interrupted by a SIGKILL
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*/
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void request_send(struct fuse_conn *fc, struct fuse_req *req)
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2005-09-10 04:10:27 +08:00
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{
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req->isreply = 1;
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|
|
|
spin_lock(&fuse_lock);
|
2005-09-10 04:10:31 +08:00
|
|
|
if (!fc->connected)
|
2005-09-10 04:10:27 +08:00
|
|
|
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);
|
|
|
|
|
2005-09-10 04:10:39 +08:00
|
|
|
request_wait_answer(fc, req);
|
2005-09-10 04:10:27 +08:00
|
|
|
}
|
|
|
|
spin_unlock(&fuse_lock);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
|
|
|
|
{
|
|
|
|
spin_lock(&fuse_lock);
|
2005-09-10 04:10:31 +08:00
|
|
|
if (fc->connected) {
|
2005-09-10 04:10:27 +08:00
|
|
|
queue_request(fc, req);
|
|
|
|
spin_unlock(&fuse_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;
|
2005-09-10 04:10:31 +08:00
|
|
|
spin_lock(&fuse_lock);
|
|
|
|
background_request(fc, req);
|
|
|
|
spin_unlock(&fuse_lock);
|
2005-09-10 04:10:27 +08:00
|
|
|
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.
|
|
|
|
*/
|
2006-01-17 14:14:28 +08:00
|
|
|
static int lock_request(struct fuse_req *req)
|
2005-09-10 04:10:27 +08:00
|
|
|
{
|
|
|
|
int err = 0;
|
|
|
|
if (req) {
|
|
|
|
spin_lock(&fuse_lock);
|
|
|
|
if (req->interrupted)
|
|
|
|
err = -ENOENT;
|
|
|
|
else
|
|
|
|
req->locked = 1;
|
|
|
|
spin_unlock(&fuse_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.
|
|
|
|
*/
|
2006-01-17 14:14:28 +08:00
|
|
|
static void unlock_request(struct fuse_req *req)
|
2005-09-10 04:10:27 +08:00
|
|
|
{
|
|
|
|
if (req) {
|
|
|
|
spin_lock(&fuse_lock);
|
|
|
|
req->locked = 0;
|
|
|
|
if (req->interrupted)
|
|
|
|
wake_up(&req->waitq);
|
|
|
|
spin_unlock(&fuse_lock);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
struct fuse_copy_state {
|
|
|
|
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, int write,
|
|
|
|
struct fuse_req *req, const struct iovec *iov,
|
|
|
|
unsigned long nr_segs)
|
|
|
|
{
|
|
|
|
memset(cs, 0, sizeof(*cs));
|
|
|
|
cs->write = write;
|
|
|
|
cs->req = req;
|
|
|
|
cs->iov = iov;
|
|
|
|
cs->nr_segs = nr_segs;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Unmap and put previous page of userspace buffer */
|
2006-01-17 14:14:28 +08:00
|
|
|
static void fuse_copy_finish(struct fuse_copy_state *cs)
|
2005-09-10 04:10:27 +08:00
|
|
|
{
|
|
|
|
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->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->req);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Do as much copy to/from userspace buffer as we can */
|
2006-01-17 14:14:28 +08:00
|
|
|
static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
|
2005-09-10 04:10:27 +08:00
|
|
|
{
|
|
|
|
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
|
|
|
|
*/
|
2006-01-17 14:14:28 +08:00
|
|
|
static int fuse_copy_page(struct fuse_copy_state *cs, struct page *page,
|
|
|
|
unsigned offset, unsigned count, int zeroing)
|
2005-09-10 04:10:27 +08:00
|
|
|
{
|
|
|
|
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);
|
2006-01-17 14:14:34 +08:00
|
|
|
while (fc->connected && list_empty(&fc->pending)) {
|
2005-09-10 04:10:27 +08:00
|
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
|
|
if (signal_pending(current))
|
|
|
|
break;
|
|
|
|
|
|
|
|
spin_unlock(&fuse_lock);
|
|
|
|
schedule();
|
|
|
|
spin_lock(&fuse_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_conn *fc;
|
|
|
|
struct fuse_req *req;
|
|
|
|
struct fuse_in *in;
|
|
|
|
struct fuse_copy_state cs;
|
|
|
|
unsigned reqsize;
|
|
|
|
|
2006-01-06 16:19:40 +08:00
|
|
|
restart:
|
2005-09-10 04:10:27 +08:00
|
|
|
spin_lock(&fuse_lock);
|
|
|
|
fc = file->private_data;
|
|
|
|
err = -EPERM;
|
|
|
|
if (!fc)
|
|
|
|
goto err_unlock;
|
|
|
|
request_wait(fc);
|
|
|
|
err = -ENODEV;
|
2006-01-17 14:14:34 +08:00
|
|
|
if (!fc->connected)
|
2005-09-10 04:10:27 +08:00
|
|
|
goto err_unlock;
|
|
|
|
err = -ERESTARTSYS;
|
|
|
|
if (list_empty(&fc->pending))
|
|
|
|
goto err_unlock;
|
|
|
|
|
|
|
|
req = list_entry(fc->pending.next, struct fuse_req, list);
|
2006-01-17 14:14:31 +08:00
|
|
|
req->state = FUSE_REQ_READING;
|
2006-01-17 14:14:31 +08:00
|
|
|
list_move(&req->list, &fc->io);
|
2005-09-10 04:10:27 +08:00
|
|
|
|
|
|
|
in = &req->in;
|
2006-01-06 16:19:40 +08:00
|
|
|
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;
|
2005-09-10 04:10:27 +08:00
|
|
|
}
|
2006-01-06 16:19:40 +08:00
|
|
|
spin_unlock(&fuse_lock);
|
|
|
|
fuse_copy_init(&cs, 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);
|
2005-09-10 04:10:27 +08:00
|
|
|
fuse_copy_finish(&cs);
|
|
|
|
spin_lock(&fuse_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 {
|
2006-01-17 14:14:31 +08:00
|
|
|
req->state = FUSE_REQ_SENT;
|
2006-01-17 14:14:31 +08:00
|
|
|
list_move_tail(&req->list, &fc->processing);
|
2005-09-10 04:10:27 +08:00
|
|
|
spin_unlock(&fuse_lock);
|
|
|
|
}
|
|
|
|
return reqsize;
|
|
|
|
|
|
|
|
err_unlock:
|
|
|
|
spin_unlock(&fuse_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 -ENODEV;
|
|
|
|
|
|
|
|
fuse_copy_init(&cs, 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(&fuse_lock);
|
2006-01-17 14:14:41 +08:00
|
|
|
err = -ENOENT;
|
|
|
|
if (!fc->connected)
|
|
|
|
goto err_unlock;
|
|
|
|
|
2005-09-10 04:10:27 +08:00
|
|
|
req = request_find(fc, oh.unique);
|
|
|
|
err = -EINVAL;
|
|
|
|
if (!req)
|
|
|
|
goto err_unlock;
|
|
|
|
|
|
|
|
if (req->interrupted) {
|
2006-01-17 14:14:25 +08:00
|
|
|
spin_unlock(&fuse_lock);
|
2005-09-10 04:10:27 +08:00
|
|
|
fuse_copy_finish(&cs);
|
2006-01-17 14:14:25 +08:00
|
|
|
spin_lock(&fuse_lock);
|
|
|
|
request_end(fc, req);
|
2005-09-10 04:10:27 +08:00
|
|
|
return -ENOENT;
|
|
|
|
}
|
2006-01-17 14:14:31 +08:00
|
|
|
list_move(&req->list, &fc->io);
|
2005-09-10 04:10:27 +08:00
|
|
|
req->out.h = oh;
|
|
|
|
req->locked = 1;
|
|
|
|
cs.req = req;
|
|
|
|
spin_unlock(&fuse_lock);
|
|
|
|
|
|
|
|
err = copy_out_args(&cs, &req->out, nbytes);
|
|
|
|
fuse_copy_finish(&cs);
|
|
|
|
|
|
|
|
spin_lock(&fuse_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(&fuse_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)
|
|
|
|
{
|
|
|
|
struct fuse_conn *fc = fuse_get_conn(file);
|
|
|
|
unsigned mask = POLLOUT | POLLWRNORM;
|
|
|
|
|
|
|
|
if (!fc)
|
|
|
|
return -ENODEV;
|
|
|
|
|
|
|
|
poll_wait(file, &fc->waitq, wait);
|
|
|
|
|
|
|
|
spin_lock(&fuse_lock);
|
|
|
|
if (!list_empty(&fc->pending))
|
|
|
|
mask |= POLLIN | POLLRDNORM;
|
|
|
|
spin_unlock(&fuse_lock);
|
|
|
|
|
|
|
|
return mask;
|
|
|
|
}
|
|
|
|
|
2006-01-17 14:14:41 +08:00
|
|
|
/*
|
|
|
|
* Abort all requests on the given list (pending or processing)
|
|
|
|
*
|
|
|
|
* This function releases and reacquires fuse_lock
|
|
|
|
*/
|
2005-09-10 04:10:27 +08:00
|
|
|
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(&fuse_lock);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2006-01-17 14:14:41 +08:00
|
|
|
/*
|
|
|
|
* 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.
|
2006-01-17 14:14:42 +08:00
|
|
|
*
|
|
|
|
* 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).
|
2006-01-17 14:14:41 +08:00
|
|
|
*/
|
|
|
|
static void end_io_requests(struct fuse_conn *fc)
|
|
|
|
{
|
|
|
|
while (!list_empty(&fc->io)) {
|
2006-01-17 14:14:42 +08:00
|
|
|
struct fuse_req *req =
|
|
|
|
list_entry(fc->io.next, struct fuse_req, list);
|
|
|
|
void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
|
|
|
|
|
2006-01-17 14:14:41 +08:00
|
|
|
req->interrupted = 1;
|
|
|
|
req->out.h.error = -ECONNABORTED;
|
|
|
|
req->state = FUSE_REQ_FINISHED;
|
|
|
|
list_del_init(&req->list);
|
|
|
|
wake_up(&req->waitq);
|
2006-01-17 14:14:42 +08:00
|
|
|
if (end) {
|
|
|
|
req->end = NULL;
|
|
|
|
/* The end function will consume this reference */
|
|
|
|
__fuse_get_request(req);
|
|
|
|
spin_unlock(&fuse_lock);
|
|
|
|
wait_event(req->waitq, !req->locked);
|
|
|
|
end(fc, req);
|
|
|
|
spin_lock(&fuse_lock);
|
|
|
|
}
|
2006-01-17 14:14:41 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* 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(&fuse_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);
|
|
|
|
}
|
|
|
|
spin_unlock(&fuse_lock);
|
|
|
|
}
|
|
|
|
|
2005-09-10 04:10:27 +08:00
|
|
|
static int fuse_dev_release(struct inode *inode, struct file *file)
|
|
|
|
{
|
|
|
|
struct fuse_conn *fc;
|
|
|
|
|
|
|
|
spin_lock(&fuse_lock);
|
|
|
|
fc = file->private_data;
|
|
|
|
if (fc) {
|
2005-09-10 04:10:31 +08:00
|
|
|
fc->connected = 0;
|
2005-09-10 04:10:27 +08:00
|
|
|
end_requests(fc, &fc->pending);
|
|
|
|
end_requests(fc, &fc->processing);
|
|
|
|
}
|
|
|
|
spin_unlock(&fuse_lock);
|
2006-01-17 14:14:35 +08:00
|
|
|
if (fc)
|
|
|
|
kobject_put(&fc->kobj);
|
|
|
|
|
2005-09-10 04:10:27 +08:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2006-03-28 17:56:42 +08:00
|
|
|
const struct file_operations fuse_dev_operations = {
|
2005-09-10 04:10:27 +08:00
|
|
|
.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,
|
|
|
|
};
|
|
|
|
|
|
|
|
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);
|
|
|
|
}
|