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/smp_lock.h>
  34 #include <linux/inet.h>
  35 #include <linux/list.h>
  36 #include <asm/uaccess.h>
  37 #include <linux/idr.h>
  38
  39 #include "debug.h"
  40 #include "v9fs.h"
  41 #include "9p.h"
  42 #include "v9fs_vfs.h"
  43 #include "fid.h"
  44
  45 static const struct file_operations v9fs_cached_file_operations;
  46
  47 /**
  48  * v9fs_file_open - open a file (or directory)
  49  * @inode: inode to be opened
  50  * @file: file being opened
  51  *
  52  */
  53
  54 int v9fs_file_open(struct inode *inode, struct file *file)
  55 {
  56         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
  57         struct v9fs_fid *vfid;
  58         struct v9fs_fcall *fcall = NULL;
  59         int omode;
  60         int err;
  61
  62         dprintk(DEBUG_VFS, "inode: %p file: %p \n", inode, file);
  63
  64         vfid = v9fs_fid_clone(file->f_path.dentry);
  65         if (IS_ERR(vfid))
  66                 return PTR_ERR(vfid);
  67
  68         omode = v9fs_uflags2omode(file->f_flags);
  69         err = v9fs_t_open(v9ses, vfid->fid, omode, &fcall);
  70         if (err < 0) {
  71                 PRINT_FCALL_ERROR("open failed", fcall);
  72                 goto Clunk_Fid;
  73         }
  74
  75         file->private_data = vfid;
  76         vfid->fidopen = 1;
  77         vfid->fidclunked = 0;
  78         vfid->iounit = fcall->params.ropen.iounit;
  79         vfid->rdir_pos = 0;
  80         vfid->rdir_fcall = NULL;
  81         vfid->filp = file;
  82         kfree(fcall);
  83
  84         if((vfid->qid.version) && (v9ses->cache)) {
  85                 dprintk(DEBUG_VFS, "cached");
  86                 /* enable cached file options */
  87                 if(file->f_op == &v9fs_file_operations)
  88                         file->f_op = &v9fs_cached_file_operations;
  89         }
  90
  91         return 0;
  92
  93 Clunk_Fid:
  94         v9fs_fid_clunk(v9ses, vfid);
  95         kfree(fcall);
  96
  97         return err;
  98 }
  99
 100 /**
 101  * v9fs_file_lock - lock a file (or directory)
 102  * @inode: inode to be opened
 103  * @file: file being opened
 104  *
 105  * XXX - this looks like a local only lock, we should extend into 9P
 106  *       by using open exclusive
 107  */
 108
 109 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 110 {
 111         int res = 0;
 112         struct inode *inode = filp->f_path.dentry->d_inode;
 113
 114         dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 115
 116         /* No mandatory locks */
 117         if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
 118                 return -ENOLCK;
 119
 120         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 121                 filemap_write_and_wait(inode->i_mapping);
 122                 invalidate_mapping_pages(&inode->i_data, 0, -1);
 123         }
 124
 125         return res;
 126 }
 127
 128 /**
 129  * v9fs_file_read - read from a file
 130  * @filep: file pointer to read
 131  * @data: data buffer to read data into
 132  * @count: size of buffer
 133  * @offset: offset at which to read data
 134  *
 135  */
 136 static ssize_t
 137 v9fs_file_read(struct file *filp, char __user * data, size_t count,
 138                loff_t * offset)
 139 {
 140         struct inode *inode = filp->f_path.dentry->d_inode;
 141         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 142         struct v9fs_fid *v9f = filp->private_data;
 143         struct v9fs_fcall *fcall = NULL;
 144         int fid = v9f->fid;
 145         int rsize = 0;
 146         int result = 0;
 147         int total = 0;
 148         int n;
 149
 150         dprintk(DEBUG_VFS, "\n");
 151
 152         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 153         if (v9f->iounit != 0 && rsize > v9f->iounit)
 154                 rsize = v9f->iounit;
 155
 156         do {
 157                 if (count < rsize)
 158                         rsize = count;
 159
 160                 result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
 161
 162                 if (result < 0) {
 163                         printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
 164                                result);
 165
 166                         kfree(fcall);
 167                         return total;
 168                 } else
 169                         *offset += result;
 170
 171                 n = copy_to_user(data, fcall->params.rread.data, result);
 172                 if (n) {
 173                         dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
 174                         kfree(fcall);
 175                         return -EFAULT;
 176                 }
 177
 178                 count -= result;
 179                 data += result;
 180                 total += result;
 181
 182                 kfree(fcall);
 183
 184                 if (result < rsize)
 185                         break;
 186         } while (count);
 187
 188         return total;
 189 }
 190
 191 /**
 192  * v9fs_file_write - write to a file
 193  * @filep: file pointer to write
 194  * @data: data buffer to write data from
 195  * @count: size of buffer
 196  * @offset: offset at which to write data
 197  *
 198  */
 199
 200 static ssize_t
 201 v9fs_file_write(struct file *filp, const char __user * data,
 202                 size_t count, loff_t * offset)
 203 {
 204         struct inode *inode = filp->f_path.dentry->d_inode;
 205         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 206         struct v9fs_fid *v9fid = filp->private_data;
 207         struct v9fs_fcall *fcall;
 208         int fid = v9fid->fid;
 209         int result = -EIO;
 210         int rsize = 0;
 211         int total = 0;
 212
 213         dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
 214                 (int)*offset);
 215         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 216         if (v9fid->iounit != 0 && rsize > v9fid->iounit)
 217                 rsize = v9fid->iounit;
 218
 219         do {
 220                 if (count < rsize)
 221                         rsize = count;
 222
 223                 result = v9fs_t_write(v9ses, fid, *offset, rsize, data, &fcall);
 224                 if (result < 0) {
 225                         PRINT_FCALL_ERROR("error while writing", fcall);
 226                         kfree(fcall);
 227                         return result;
 228                 } else
 229                         *offset += result;
 230
 231                 kfree(fcall);
 232                 fcall = NULL;
 233
 234                 if (result != rsize) {
 235                         eprintk(KERN_ERR,
 236                                 "short write: v9fs_t_write returned %d\n",
 237                                 result);
 238                         break;
 239                 }
 240
 241                 count -= result;
 242                 data += result;
 243                 total += result;
 244         } while (count);
 245
 246         invalidate_inode_pages2(inode->i_mapping);
 247         return total;
 248 }
 249
 250 static const struct file_operations v9fs_cached_file_operations = {
 251         .llseek = generic_file_llseek,
 252         .read = do_sync_read,
 253         .aio_read = generic_file_aio_read,
 254         .write = v9fs_file_write,
 255         .open = v9fs_file_open,
 256         .release = v9fs_dir_release,
 257         .lock = v9fs_file_lock,
 258         .mmap = generic_file_mmap,
 259 };
 260
 261 const struct file_operations v9fs_file_operations = {
 262         .llseek = generic_file_llseek,
 263         .read = v9fs_file_read,
 264         .write = v9fs_file_write,
 265         .open = v9fs_file_open,
 266         .release = v9fs_dir_release,
 267         .lock = v9fs_file_lock,
 268         .mmap = generic_file_mmap,
 269 };