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b93f858ab2
Add fuse_ prefix to request_send*() and get_root_inode() as some of those functions will be exported for CUSE. With or without CUSE export, having the function names scoped is a good idea for debuggability. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
1165 lines
27 KiB
C
1165 lines
27 KiB
C
/*
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FUSE: Filesystem in Userspace
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Copyright (C) 2001-2008 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 struct kmem_cache *fuse_req_cachep;
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static struct fuse_conn *fuse_get_conn(struct file *file)
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{
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/*
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* Lockless access is OK, because file->private data is set
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* once during mount and is valid until the file is released.
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*/
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return file->private_data;
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}
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static void fuse_request_init(struct fuse_req *req)
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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_LIST_HEAD(&req->intr_entry);
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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, GFP_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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struct fuse_req *fuse_request_alloc_nofs(void)
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{
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struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, GFP_NOFS);
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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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static void block_sigs(sigset_t *oldset)
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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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static void restore_sigs(sigset_t *oldset)
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{
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sigprocmask(SIG_SETMASK, oldset, NULL);
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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 void fuse_req_init_context(struct fuse_req *req)
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{
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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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}
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struct fuse_req *fuse_get_req(struct fuse_conn *fc)
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{
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struct fuse_req *req;
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sigset_t oldset;
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int intr;
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int err;
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atomic_inc(&fc->num_waiting);
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block_sigs(&oldset);
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intr = wait_event_interruptible(fc->blocked_waitq, !fc->blocked);
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restore_sigs(&oldset);
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err = -EINTR;
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if (intr)
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goto out;
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err = -ENOTCONN;
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if (!fc->connected)
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goto out;
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req = fuse_request_alloc();
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err = -ENOMEM;
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if (!req)
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goto out;
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fuse_req_init_context(req);
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req->waiting = 1;
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return req;
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out:
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atomic_dec(&fc->num_waiting);
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return ERR_PTR(err);
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}
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/*
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* Return request in fuse_file->reserved_req. However that may
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* currently be in use. If that is the case, wait for it to become
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* available.
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*/
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static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
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struct file *file)
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{
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struct fuse_req *req = NULL;
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struct fuse_file *ff = file->private_data;
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do {
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wait_event(fc->reserved_req_waitq, ff->reserved_req);
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spin_lock(&fc->lock);
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if (ff->reserved_req) {
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req = ff->reserved_req;
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ff->reserved_req = NULL;
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get_file(file);
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req->stolen_file = file;
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}
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spin_unlock(&fc->lock);
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} while (!req);
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return req;
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}
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/*
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* Put stolen request back into fuse_file->reserved_req
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*/
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static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
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{
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struct file *file = req->stolen_file;
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struct fuse_file *ff = file->private_data;
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spin_lock(&fc->lock);
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fuse_request_init(req);
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BUG_ON(ff->reserved_req);
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ff->reserved_req = req;
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wake_up_all(&fc->reserved_req_waitq);
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spin_unlock(&fc->lock);
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fput(file);
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}
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/*
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* Gets a requests for a file operation, always succeeds
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*
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* This is used for sending the FLUSH request, which must get to
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* userspace, due to POSIX locks which may need to be unlocked.
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*
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* If allocation fails due to OOM, use the reserved request in
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* fuse_file.
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*
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* This is very unlikely to deadlock accidentally, since the
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* filesystem should not have it's own file open. If deadlock is
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* intentional, it can still be broken by "aborting" the filesystem.
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*/
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struct fuse_req *fuse_get_req_nofail(struct fuse_conn *fc, struct file *file)
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{
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struct fuse_req *req;
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atomic_inc(&fc->num_waiting);
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wait_event(fc->blocked_waitq, !fc->blocked);
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req = fuse_request_alloc();
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if (!req)
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req = get_reserved_req(fc, file);
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fuse_req_init_context(req);
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req->waiting = 1;
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return req;
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}
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void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
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{
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if (atomic_dec_and_test(&req->count)) {
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if (req->waiting)
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atomic_dec(&fc->num_waiting);
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if (req->stolen_file)
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put_reserved_req(fc, req);
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else
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fuse_request_free(req);
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}
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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 u64 fuse_get_unique(struct fuse_conn *fc)
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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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return fc->reqctr;
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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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req->in.h.unique = fuse_get_unique(fc);
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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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list_add_tail(&req->list, &fc->pending);
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req->state = FUSE_REQ_PENDING;
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if (!req->waiting) {
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req->waiting = 1;
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atomic_inc(&fc->num_waiting);
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}
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wake_up(&fc->waitq);
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kill_fasync(&fc->fasync, SIGIO, POLL_IN);
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}
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static void flush_bg_queue(struct fuse_conn *fc)
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{
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while (fc->active_background < FUSE_MAX_BACKGROUND &&
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!list_empty(&fc->bg_queue)) {
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struct fuse_req *req;
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req = list_entry(fc->bg_queue.next, struct fuse_req, list);
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list_del(&req->list);
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fc->active_background++;
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queue_request(fc, req);
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}
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}
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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 aborted (and not yet sent) or some error
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* occurred during communication with userspace, or the device file
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* was closed. The requester thread is woken up (if still waiting),
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* the 'end' callback is called if given, else the reference to the
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* request is released
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*
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* Called with fc->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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__releases(fc->lock)
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{
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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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list_del(&req->list);
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list_del(&req->intr_entry);
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req->state = FUSE_REQ_FINISHED;
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if (req->background) {
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if (fc->num_background == FUSE_MAX_BACKGROUND) {
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fc->blocked = 0;
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wake_up_all(&fc->blocked_waitq);
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}
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if (fc->num_background == FUSE_CONGESTION_THRESHOLD) {
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clear_bdi_congested(&fc->bdi, READ);
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clear_bdi_congested(&fc->bdi, WRITE);
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}
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fc->num_background--;
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fc->active_background--;
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flush_bg_queue(fc);
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}
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spin_unlock(&fc->lock);
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wake_up(&req->waitq);
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if (end)
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end(fc, req);
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fuse_put_request(fc, req);
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}
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static void wait_answer_interruptible(struct fuse_conn *fc,
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struct fuse_req *req)
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__releases(fc->lock) __acquires(fc->lock)
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{
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if (signal_pending(current))
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return;
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spin_unlock(&fc->lock);
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wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
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spin_lock(&fc->lock);
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}
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static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req)
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{
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list_add_tail(&req->intr_entry, &fc->interrupts);
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wake_up(&fc->waitq);
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kill_fasync(&fc->fasync, SIGIO, POLL_IN);
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}
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static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
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__releases(fc->lock) __acquires(fc->lock)
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{
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if (!fc->no_interrupt) {
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/* Any signal may interrupt this */
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wait_answer_interruptible(fc, req);
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if (req->aborted)
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goto aborted;
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if (req->state == FUSE_REQ_FINISHED)
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return;
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req->interrupted = 1;
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if (req->state == FUSE_REQ_SENT)
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queue_interrupt(fc, req);
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}
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if (!req->force) {
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sigset_t oldset;
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/* Only fatal signals may interrupt this */
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block_sigs(&oldset);
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wait_answer_interruptible(fc, req);
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restore_sigs(&oldset);
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if (req->aborted)
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goto aborted;
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if (req->state == FUSE_REQ_FINISHED)
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return;
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/* Request is not yet in userspace, bail out */
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if (req->state == FUSE_REQ_PENDING) {
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list_del(&req->list);
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__fuse_put_request(req);
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req->out.h.error = -EINTR;
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return;
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}
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}
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/*
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* Either request is already in userspace, or it was forced.
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* Wait it out.
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*/
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spin_unlock(&fc->lock);
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wait_event(req->waitq, req->state == FUSE_REQ_FINISHED);
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spin_lock(&fc->lock);
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if (!req->aborted)
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return;
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aborted:
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BUG_ON(req->state != FUSE_REQ_FINISHED);
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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(&fc->lock);
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wait_event(req->waitq, !req->locked);
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spin_lock(&fc->lock);
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}
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}
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void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
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{
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req->isreply = 1;
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spin_lock(&fc->lock);
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if (!fc->connected)
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req->out.h.error = -ENOTCONN;
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else if (fc->conn_error)
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req->out.h.error = -ECONNREFUSED;
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else {
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queue_request(fc, req);
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/* acquire extra reference, since request is still needed
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after request_end() */
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__fuse_get_request(req);
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request_wait_answer(fc, req);
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}
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spin_unlock(&fc->lock);
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}
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static void fuse_request_send_nowait_locked(struct fuse_conn *fc,
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struct fuse_req *req)
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{
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req->background = 1;
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fc->num_background++;
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if (fc->num_background == FUSE_MAX_BACKGROUND)
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fc->blocked = 1;
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if (fc->num_background == FUSE_CONGESTION_THRESHOLD) {
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set_bdi_congested(&fc->bdi, READ);
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set_bdi_congested(&fc->bdi, WRITE);
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}
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list_add_tail(&req->list, &fc->bg_queue);
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flush_bg_queue(fc);
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}
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static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
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{
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spin_lock(&fc->lock);
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if (fc->connected) {
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fuse_request_send_nowait_locked(fc, req);
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spin_unlock(&fc->lock);
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} else {
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req->out.h.error = -ENOTCONN;
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request_end(fc, req);
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}
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}
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void fuse_request_send_noreply(struct fuse_conn *fc, struct fuse_req *req)
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{
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req->isreply = 0;
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fuse_request_send_nowait(fc, req);
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}
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void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
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{
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req->isreply = 1;
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fuse_request_send_nowait(fc, req);
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}
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/*
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* Called under fc->lock
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*
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* fc->connected must have been checked previously
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*/
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void fuse_request_send_background_locked(struct fuse_conn *fc,
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struct fuse_req *req)
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{
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req->isreply = 1;
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fuse_request_send_nowait_locked(fc, req);
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}
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/*
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* Lock the request. Up to the next unlock_request() there mustn't be
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* anything that could cause a page-fault. If the request was already
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* aborted bail out.
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*/
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static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
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{
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int err = 0;
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if (req) {
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spin_lock(&fc->lock);
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if (req->aborted)
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err = -ENOENT;
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else
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req->locked = 1;
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spin_unlock(&fc->lock);
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}
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return err;
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}
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/*
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* Unlock request. If it was aborted during being locked, the
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* requester thread is currently waiting for it to be unlocked, so
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* wake it up.
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*/
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static void unlock_request(struct fuse_conn *fc, struct fuse_req *req)
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{
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if (req) {
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spin_lock(&fc->lock);
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req->locked = 0;
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if (req->aborted)
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wake_up(&req->waitq);
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spin_unlock(&fc->lock);
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}
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}
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struct fuse_copy_state {
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struct fuse_conn *fc;
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int write;
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struct fuse_req *req;
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const struct iovec *iov;
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unsigned long nr_segs;
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unsigned long seglen;
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unsigned long addr;
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struct page *pg;
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void *mapaddr;
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void *buf;
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unsigned len;
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};
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static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc,
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int write, struct fuse_req *req,
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const struct iovec *iov, unsigned long nr_segs)
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{
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memset(cs, 0, sizeof(*cs));
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cs->fc = fc;
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cs->write = write;
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cs->req = req;
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cs->iov = iov;
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cs->nr_segs = nr_segs;
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}
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/* Unmap and put previous page of userspace buffer */
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static void fuse_copy_finish(struct fuse_copy_state *cs)
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{
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if (cs->mapaddr) {
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kunmap_atomic(cs->mapaddr, KM_USER0);
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if (cs->write) {
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flush_dcache_page(cs->pg);
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set_page_dirty_lock(cs->pg);
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}
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put_page(cs->pg);
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cs->mapaddr = NULL;
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}
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}
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|
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/*
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* Get another pagefull of userspace buffer, and map it to kernel
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* address space, and lock request
|
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*/
|
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static int fuse_copy_fill(struct fuse_copy_state *cs)
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{
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unsigned long offset;
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int err;
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|
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unlock_request(cs->fc, cs->req);
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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) {
|
|
if (!cs->len) {
|
|
int err = fuse_copy_fill(cs);
|
|
if (err)
|
|
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) {
|
|
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 request_pending(struct fuse_conn *fc)
|
|
{
|
|
return !list_empty(&fc->pending) || !list_empty(&fc->interrupts);
|
|
}
|
|
|
|
/* 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 && !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_req *req,
|
|
const struct iovec *iov, unsigned long nr_segs)
|
|
__releases(fc->lock)
|
|
{
|
|
struct fuse_copy_state cs;
|
|
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 (iov_length(iov, nr_segs) < reqsize)
|
|
return -EINVAL;
|
|
|
|
fuse_copy_init(&cs, fc, 1, NULL, iov, nr_segs);
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* 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_read(struct kiocb *iocb, const struct iovec *iov,
|
|
unsigned long nr_segs, loff_t pos)
|
|
{
|
|
int err;
|
|
struct fuse_req *req;
|
|
struct fuse_in *in;
|
|
struct fuse_copy_state cs;
|
|
unsigned reqsize;
|
|
struct file *file = iocb->ki_filp;
|
|
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 &&
|
|
!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, req, iov, nr_segs);
|
|
}
|
|
|
|
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 (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_notify_poll(struct fuse_conn *fc, unsigned int size,
|
|
struct fuse_copy_state *cs)
|
|
{
|
|
struct fuse_notify_poll_wakeup_out outarg;
|
|
int err;
|
|
|
|
if (size != sizeof(outarg))
|
|
return -EINVAL;
|
|
|
|
err = fuse_copy_one(cs, &outarg, sizeof(outarg));
|
|
if (err)
|
|
return err;
|
|
|
|
return fuse_notify_poll_wakeup(fc, &outarg);
|
|
}
|
|
|
|
static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
|
|
unsigned int size, struct fuse_copy_state *cs)
|
|
{
|
|
switch (code) {
|
|
case FUSE_NOTIFY_POLL:
|
|
return fuse_notify_poll(fc, size, cs);
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
/* 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 || 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_write(struct kiocb *iocb, const struct iovec *iov,
|
|
unsigned long nr_segs, loff_t pos)
|
|
{
|
|
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(iocb->ki_filp);
|
|
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.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);
|
|
fuse_copy_finish(&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;
|
|
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 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)
|
|
{
|
|
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);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
end_io_requests(fc);
|
|
end_requests(fc, &fc->pending);
|
|
end_requests(fc, &fc->processing);
|
|
wake_up_all(&fc->waitq);
|
|
wake_up_all(&fc->blocked_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);
|
|
fuse_conn_put(fc);
|
|
}
|
|
|
|
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 = do_sync_read,
|
|
.aio_read = fuse_dev_read,
|
|
.write = do_sync_write,
|
|
.aio_write = fuse_dev_write,
|
|
.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);
|
|
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);
|
|
}
|