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
  38 #include "debug.h"
  39 #include "v9fs.h"
  40 #include "9p.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         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
  56         struct v9fs_fid *vfid;
  57         struct v9fs_fcall *fcall = NULL;
  58         int omode;
  59         int err;
  60
  61         dprintk(DEBUG_VFS, "inode: %p file: %p \n", inode, file);
  62
  63         vfid = v9fs_fid_clone(file->f_path.dentry);
  64         if (IS_ERR(vfid))
  65                 return PTR_ERR(vfid);
  66
  67         omode = v9fs_uflags2omode(file->f_flags);
  68         err = v9fs_t_open(v9ses, vfid->fid, omode, &fcall);
  69         if (err < 0) {
  70                 PRINT_FCALL_ERROR("open failed", fcall);
  71                 goto Clunk_Fid;
  72         }
  73
  74         file->private_data = vfid;
  75         vfid->fidopen = 1;
  76         vfid->fidclunked = 0;
  77         vfid->iounit = fcall->params.ropen.iounit;
  78         vfid->rdir_pos = 0;
  79         vfid->rdir_fcall = NULL;
  80         vfid->filp = file;
  81         kfree(fcall);
  82
  83         if((vfid->qid.version) && (v9ses->cache)) {
  84                 dprintk(DEBUG_VFS, "cached");
  85                 /* enable cached file options */
  86                 if(file->f_op == &v9fs_file_operations)
  87                         file->f_op = &v9fs_cached_file_operations;
  88         }
  89
  90         return 0;
  91
  92 Clunk_Fid:
  93         v9fs_fid_clunk(v9ses, vfid);
  94         kfree(fcall);
  95
  96         return err;
  97 }
  98
  99 /**
 100  * v9fs_file_lock - lock a file (or directory)
 101  * @inode: inode to be opened
 102  * @file: file being opened
 103  *
 104  * XXX - this looks like a local only lock, we should extend into 9P
 105  *       by using open exclusive
 106  */
 107
 108 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 109 {
 110         int res = 0;
 111         struct inode *inode = filp->f_path.dentry->d_inode;
 112
 113         dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 114
 115         /* No mandatory locks */
 116         if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
 117                 return -ENOLCK;
 118
 119         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 120                 filemap_write_and_wait(inode->i_mapping);
 121                 invalidate_mapping_pages(&inode->i_data, 0, -1);
 122         }
 123
 124         return res;
 125 }
 126
 127 /**
 128  * v9fs_file_read - read from a file
 129  * @filep: file pointer to read
 130  * @data: data buffer to read data into
 131  * @count: size of buffer
 132  * @offset: offset at which to read data
 133  *
 134  */
 135 static ssize_t
 136 v9fs_file_read(struct file *filp, char __user * data, size_t count,
 137                loff_t * offset)
 138 {
 139         struct inode *inode = filp->f_path.dentry->d_inode;
 140         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 141         struct v9fs_fid *v9f = filp->private_data;
 142         struct v9fs_fcall *fcall = NULL;
 143         int fid = v9f->fid;
 144         int rsize = 0;
 145         int result = 0;
 146         int total = 0;
 147         int n;
 148
 149         dprintk(DEBUG_VFS, "\n");
 150
 151         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 152         if (v9f->iounit != 0 && rsize > v9f->iounit)
 153                 rsize = v9f->iounit;
 154
 155         do {
 156                 if (count < rsize)
 157                         rsize = count;
 158
 159                 result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
 160
 161                 if (result < 0) {
 162                         printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
 163                                result);
 164
 165                         kfree(fcall);
 166                         return total;
 167                 } else
 168                         *offset += result;
 169
 170                 n = copy_to_user(data, fcall->params.rread.data, result);
 171                 if (n) {
 172                         dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
 173                         kfree(fcall);
 174                         return -EFAULT;
 175                 }
 176
 177                 count -= result;
 178                 data += result;
 179                 total += result;
 180
 181                 kfree(fcall);
 182
 183                 if (result < rsize)
 184                         break;
 185         } while (count);
 186
 187         return total;
 188 }
 189
 190 /**
 191  * v9fs_file_write - write to a file
 192  * @filep: file pointer to write
 193  * @data: data buffer to write data from
 194  * @count: size of buffer
 195  * @offset: offset at which to write data
 196  *
 197  */
 198
 199 static ssize_t
 200 v9fs_file_write(struct file *filp, const char __user * data,
 201                 size_t count, loff_t * offset)
 202 {
 203         struct inode *inode = filp->f_path.dentry->d_inode;
 204         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 205         struct v9fs_fid *v9fid = filp->private_data;
 206         struct v9fs_fcall *fcall;
 207         int fid = v9fid->fid;
 208         int result = -EIO;
 209         int rsize = 0;
 210         int total = 0;
 211
 212         dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
 213                 (int)*offset);
 214         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 215         if (v9fid->iounit != 0 && rsize > v9fid->iounit)
 216                 rsize = v9fid->iounit;
 217
 218         do {
 219                 if (count < rsize)
 220                         rsize = count;
 221
 222                 result = v9fs_t_write(v9ses, fid, *offset, rsize, data, &fcall);
 223                 if (result < 0) {
 224                         PRINT_FCALL_ERROR("error while writing", fcall);
 225                         kfree(fcall);
 226                         return result;
 227                 } else
 228                         *offset += result;
 229
 230                 kfree(fcall);
 231                 fcall = NULL;
 232
 233                 if (result != rsize) {
 234                         eprintk(KERN_ERR,
 235                                 "short write: v9fs_t_write returned %d\n",
 236                                 result);
 237                         break;
 238                 }
 239
 240                 count -= result;
 241                 data += result;
 242                 total += result;
 243         } while (count);
 244
 245         invalidate_inode_pages2(inode->i_mapping);
 246         return total;
 247 }
 248
 249 static const struct file_operations v9fs_cached_file_operations = {
 250         .llseek = generic_file_llseek,
 251         .read = do_sync_read,
 252         .aio_read = generic_file_aio_read,
 253         .write = v9fs_file_write,
 254         .open = v9fs_file_open,
 255         .release = v9fs_dir_release,
 256         .lock = v9fs_file_lock,
 257         .mmap = generic_file_mmap,
 258 };
 259
 260 const struct file_operations v9fs_file_operations = {
 261         .llseek = generic_file_llseek,
 262         .read = v9fs_file_read,
 263         .write = v9fs_file_write,
 264         .open = v9fs_file_open,
 265         .release = v9fs_dir_release,
 266         .lock = v9fs_file_lock,
 267         .mmap = generic_file_mmap,
 268 };