root/fs/9p/vfs_file.c

DEFINITIONS

1. v9fs_file_open
2. v9fs_file_lock
3. v9fs_file_read
4. v9fs_file_write

/*
 *  linux/fs/9p/vfs_file.c
 *
 * This file contians vfs file ops for 9P2000.
 *
 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License 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.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/inet.h>
#include <linux/list.h>
#include <asm/uaccess.h>
#include <linux/idr.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>

#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"

static const struct file_operations v9fs_cached_file_operations;

/**
 * v9fs_file_open - open a file (or directory)
 * @inode: inode to be opened
 * @file: file being opened
 *
 */

int v9fs_file_open(struct inode *inode, struct file *file)
{
        int err;
        struct v9fs_session_info *v9ses;
        struct p9_fid *fid;
        int omode;

        P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p \n", inode, file);
        v9ses = v9fs_inode2v9ses(inode);
        omode = v9fs_uflags2omode(file->f_flags, v9fs_extended(v9ses));
        fid = file->private_data;
        if (!fid) {
                fid = v9fs_fid_clone(file->f_path.dentry);
                if (IS_ERR(fid))
                        return PTR_ERR(fid);

                err = p9_client_open(fid, omode);
                if (err < 0) {
                        p9_client_clunk(fid);
                        return err;
                }
                if (omode & P9_OTRUNC) {
                        inode->i_size = 0;
                        inode->i_blocks = 0;
                }
                if ((file->f_flags & O_APPEND) && (!v9fs_extended(v9ses)))
                        generic_file_llseek(file, 0, SEEK_END);
        }

        file->private_data = fid;
        if ((fid->qid.version) && (v9ses->cache)) {
                P9_DPRINTK(P9_DEBUG_VFS, "cached");
                /* enable cached file options */
                if(file->f_op == &v9fs_file_operations)
                        file->f_op = &v9fs_cached_file_operations;
        }

        return 0;
}

/**
 * v9fs_file_lock - lock a file (or directory)
 * @filp: file to be locked
 * @cmd: lock command
 * @fl: file lock structure
 *
 * Bugs: this looks like a local only lock, we should extend into 9P
 *       by using open exclusive
 */

static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
{
        int res = 0;
        struct inode *inode = filp->f_path.dentry->d_inode;

        P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);

        /* No mandatory locks */
        if (__mandatory_lock(inode))
                return -ENOLCK;

        if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
                filemap_write_and_wait(inode->i_mapping);
                invalidate_mapping_pages(&inode->i_data, 0, -1);
        }

        return res;
}

/**
 * v9fs_file_read - read from a file
 * @filp: file pointer to read
 * @data: data buffer to read data into
 * @count: size of buffer
 * @offset: offset at which to read data
 *
 */
static ssize_t
v9fs_file_read(struct file *filp, char __user * data, size_t count,
               loff_t * offset)
{
        int ret;
        struct p9_fid *fid;

        P9_DPRINTK(P9_DEBUG_VFS, "\n");
        fid = filp->private_data;
        ret = p9_client_uread(fid, data, *offset, count);
        if (ret > 0)
                *offset += ret;

        return ret;
}

/**
 * v9fs_file_write - write to a file
 * @filp: file pointer to write
 * @data: data buffer to write data from
 * @count: size of buffer
 * @offset: offset at which to write data
 *
 */

static ssize_t
v9fs_file_write(struct file *filp, const char __user * data,
                size_t count, loff_t * offset)
{
        int ret;
        struct p9_fid *fid;
        struct inode *inode = filp->f_path.dentry->d_inode;

        P9_DPRINTK(P9_DEBUG_VFS, "data %p count %d offset %x\n", data,
                (int)count, (int)*offset);

        fid = filp->private_data;
        ret = p9_client_uwrite(fid, data, *offset, count);
        if (ret > 0) {
                invalidate_inode_pages2_range(inode->i_mapping, *offset,
                                                                *offset+ret);
                *offset += ret;
        }

        if (*offset > inode->i_size) {
                inode->i_size = *offset;
                inode->i_blocks = (inode->i_size + 512 - 1) >> 9;
        }

        return ret;
}

static const struct file_operations v9fs_cached_file_operations = {
        .llseek = generic_file_llseek,
        .read = do_sync_read,
        .aio_read = generic_file_aio_read,
        .write = v9fs_file_write,
        .open = v9fs_file_open,
        .release = v9fs_dir_release,
        .lock = v9fs_file_lock,
        .mmap = generic_file_readonly_mmap,
};

const struct file_operations v9fs_file_operations = {
        .llseek = generic_file_llseek,
        .read = v9fs_file_read,
        .write = v9fs_file_write,
        .open = v9fs_file_open,
        .release = v9fs_dir_release,
        .lock = v9fs_file_lock,
        .mmap = generic_file_readonly_mmap,
};