115 lines
2.9 KiB
C
115 lines
2.9 KiB
C
/*
|
|
* Copyright (c) 2015, The Linux Foundation. All rights reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 and
|
|
* only version 2 as published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
*/
|
|
|
|
#include "fuse_shortcircuit.h"
|
|
|
|
#include <linux/aio.h>
|
|
#include <linux/fs_stack.h>
|
|
|
|
void fuse_setup_shortcircuit(struct fuse_conn *fc, struct fuse_req *req)
|
|
{
|
|
int daemon_fd;
|
|
struct file *rw_lower_file = NULL;
|
|
struct fuse_open_out *open_out;
|
|
int open_out_index;
|
|
|
|
req->private_lower_rw_file = NULL;
|
|
|
|
if (!(fc->shortcircuit_io))
|
|
return;
|
|
|
|
if ((req->in.h.opcode != FUSE_OPEN) &&
|
|
(req->in.h.opcode != FUSE_CREATE))
|
|
return;
|
|
|
|
open_out_index = req->in.numargs - 1;
|
|
|
|
BUG_ON(open_out_index != 0 && open_out_index != 1);
|
|
BUG_ON(req->out.args[open_out_index].size != sizeof(*open_out));
|
|
|
|
open_out = req->out.args[open_out_index].value;
|
|
|
|
daemon_fd = (int)open_out->lower_fd;
|
|
if (daemon_fd < 0)
|
|
return;
|
|
|
|
rw_lower_file = fget_raw(daemon_fd);
|
|
if (!rw_lower_file)
|
|
return;
|
|
req->private_lower_rw_file = rw_lower_file;
|
|
}
|
|
|
|
static ssize_t fuse_shortcircuit_read_write_iter(struct kiocb *iocb,
|
|
struct iov_iter *iter,
|
|
int do_write)
|
|
{
|
|
ssize_t ret_val;
|
|
struct fuse_file *ff;
|
|
struct file *fuse_file, *lower_file;
|
|
struct inode *fuse_inode, *lower_inode;
|
|
|
|
ff = iocb->ki_filp->private_data;
|
|
fuse_file = iocb->ki_filp;
|
|
lower_file = ff->rw_lower_file;
|
|
|
|
/* lock lower file to prevent it from being released */
|
|
get_file(lower_file);
|
|
iocb->ki_filp = lower_file;
|
|
fuse_inode = fuse_file->f_path.dentry->d_inode;
|
|
lower_inode = file_inode(lower_file);
|
|
|
|
if (do_write) {
|
|
if (!lower_file->f_op->write_iter)
|
|
return -EIO;
|
|
ret_val = lower_file->f_op->write_iter(iocb, iter);
|
|
|
|
if (ret_val >= 0 || ret_val == -EIOCBQUEUED) {
|
|
fsstack_copy_inode_size(fuse_inode, lower_inode);
|
|
fsstack_copy_attr_times(fuse_inode, lower_inode);
|
|
}
|
|
} else {
|
|
if (!lower_file->f_op->read_iter)
|
|
return -EIO;
|
|
ret_val = lower_file->f_op->read_iter(iocb, iter);
|
|
if (ret_val >= 0 || ret_val == -EIOCBQUEUED)
|
|
fsstack_copy_attr_atime(fuse_inode, lower_inode);
|
|
}
|
|
|
|
iocb->ki_filp = fuse_file;
|
|
fput(lower_file);
|
|
/* unlock lower file */
|
|
|
|
return ret_val;
|
|
}
|
|
|
|
ssize_t fuse_shortcircuit_read_iter(struct kiocb *iocb, struct iov_iter *to)
|
|
{
|
|
return fuse_shortcircuit_read_write_iter(iocb, to, 0);
|
|
}
|
|
|
|
ssize_t fuse_shortcircuit_write_iter(struct kiocb *iocb, struct iov_iter *from)
|
|
{
|
|
return fuse_shortcircuit_read_write_iter(iocb, from, 1);
|
|
}
|
|
|
|
void fuse_shortcircuit_release(struct fuse_file *ff)
|
|
{
|
|
if (!(ff->rw_lower_file))
|
|
return;
|
|
|
|
/* Release the lower file. */
|
|
fput(ff->rw_lower_file);
|
|
ff->rw_lower_file = NULL;
|
|
}
|