fs/9p/vfs_file.c

   1 /*
   2  *  linux/fs/9p/vfs_file.c
   3  *
   4  * This file contians vfs file ops for 9P2000.
   5  *
   6  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   7  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License version 2
  11  *  as published by the Free Software Foundation.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to:
  20  *  Free Software Foundation
  21  *  51 Franklin Street, Fifth Floor
  22  *  Boston, MA  02111-1301  USA
  23  *
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/errno.h>
  28 #include <linux/fs.h>
  29 #include <linux/sched.h>
  30 #include <linux/file.h>
  31 #include <linux/stat.h>
  32 #include <linux/string.h>
  33 #include <linux/inet.h>
  34 #include <linux/list.h>
  35 #include <asm/uaccess.h>
  36 #include <linux/idr.h>
  37 #include <net/9p/9p.h>
  38 #include <net/9p/client.h>
  39
  40 #include "v9fs.h"
  41 #include "v9fs_vfs.h"
  42 #include "fid.h"
  43
  44 static const struct file_operations v9fs_cached_file_operations;
  45
  46 /**
  47  * v9fs_file_open - open a file (or directory)
  48  * @inode: inode to be opened
  49  * @file: file being opened
  50  *
  51  */
  52
  53 int v9fs_file_open(struct inode *inode, struct file *file)
  54 {
  55         int err;
  56         struct v9fs_session_info *v9ses;
  57         struct p9_fid *fid;
  58         int omode;
  59
  60         P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p \n", inode, file);
  61         v9ses = v9fs_inode2v9ses(inode);
  62         omode = v9fs_uflags2omode(file->f_flags);
  63         fid = file->private_data;
  64         if (!fid) {
  65                 fid = v9fs_fid_clone(file->f_path.dentry);
  66                 if (IS_ERR(fid))
  67                         return PTR_ERR(fid);
  68
  69                 err = p9_client_open(fid, omode);
  70                 if (err < 0) {
  71                         p9_client_clunk(fid);
  72                         return err;
  73                 }
  74                 if (omode & P9_OTRUNC) {
  75                         inode->i_size = 0;
  76                         inode->i_blocks = 0;
  77                 }
  78         }
  79
  80         file->private_data = fid;
  81         if ((fid->qid.version) && (v9ses->cache)) {
  82                 P9_DPRINTK(P9_DEBUG_VFS, "cached");
  83                 /* enable cached file options */
  84                 if(file->f_op == &v9fs_file_operations)
  85                         file->f_op = &v9fs_cached_file_operations;
  86         }
  87
  88         return 0;
  89 }
  90
  91 /**
  92  * v9fs_file_lock - lock a file (or directory)
  93  * @filp: file to be locked
  94  * @cmd: lock command
  95  * @fl: file lock structure
  96  *
  97  * Bugs: this looks like a local only lock, we should extend into 9P
  98  *       by using open exclusive
  99  */
 100
 101 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 102 {
 103         int res = 0;
 104         struct inode *inode = filp->f_path.dentry->d_inode;
 105
 106         P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 107
 108         /* No mandatory locks */
 109         if (__mandatory_lock(inode))
 110                 return -ENOLCK;
 111
 112         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 113                 filemap_write_and_wait(inode->i_mapping);
 114                 invalidate_mapping_pages(&inode->i_data, 0, -1);
 115         }
 116
 117         return res;
 118 }
 119
 120 /**
 121  * v9fs_file_read - read from a file
 122  * @filp: file pointer to read
 123  * @data: data buffer to read data into
 124  * @count: size of buffer
 125  * @offset: offset at which to read data
 126  *
 127  */
 128 static ssize_t
 129 v9fs_file_read(struct file *filp, char __user * data, size_t count,
 130                loff_t * offset)
 131 {
 132         int ret;
 133         struct p9_fid *fid;
 134
 135         P9_DPRINTK(P9_DEBUG_VFS, "\n");
 136         fid = filp->private_data;
 137         ret = p9_client_uread(fid, data, *offset, count);
 138         if (ret > 0)
 139                 *offset += ret;
 140
 141         return ret;
 142 }
 143
 144 /**
 145  * v9fs_file_write - write to a file
 146  * @filp: file pointer to write
 147  * @data: data buffer to write data from
 148  * @count: size of buffer
 149  * @offset: offset at which to write data
 150  *
 151  */
 152
 153 static ssize_t
 154 v9fs_file_write(struct file *filp, const char __user * data,
 155                 size_t count, loff_t * offset)
 156 {
 157         int ret;
 158         struct p9_fid *fid;
 159         struct inode *inode = filp->f_path.dentry->d_inode;
 160
 161         P9_DPRINTK(P9_DEBUG_VFS, "data %p count %d offset %x\n", data,
 162                 (int)count, (int)*offset);
 163
 164         fid = filp->private_data;
 165         ret = p9_client_uwrite(fid, data, *offset, count);
 166         if (ret > 0) {
 167                 invalidate_inode_pages2_range(inode->i_mapping, *offset,
 168                                                                 *offset+ret);
 169                 *offset += ret;
 170         }
 171
 172         if (*offset > inode->i_size) {
 173                 inode->i_size = *offset;
 174                 inode->i_blocks = (inode->i_size + 512 - 1) >> 9;
 175         }
 176
 177         return ret;
 178 }
 179
 180 static const struct file_operations v9fs_cached_file_operations = {
 181         .llseek = generic_file_llseek,
 182         .read = do_sync_read,
 183         .aio_read = generic_file_aio_read,
 184         .write = v9fs_file_write,
 185         .open = v9fs_file_open,
 186         .release = v9fs_dir_release,
 187         .lock = v9fs_file_lock,
 188         .mmap = generic_file_readonly_mmap,
 189 };
 190
 191 const struct file_operations v9fs_file_operations = {
 192         .llseek = generic_file_llseek,
 193         .read = v9fs_file_read,
 194         .write = v9fs_file_write,
 195         .open = v9fs_file_open,
 196         .release = v9fs_dir_release,
 197         .lock = v9fs_file_lock,
 198         .mmap = generic_file_readonly_mmap,
 199 };