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 as published by
  11  *  the Free Software Foundation; either version 2 of the License, or
  12  *  (at your option) any later version.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program; if not, write to:
  21  *  Free Software Foundation
  22  *  51 Franklin Street, Fifth Floor
  23  *  Boston, MA  02111-1301  USA
  24  *
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/errno.h>
  29 #include <linux/fs.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/version.h>
  36 #include <linux/list.h>
  37 #include <asm/uaccess.h>
  38 #include <linux/idr.h>
  39
  40 #include "debug.h"
  41 #include "v9fs.h"
  42 #include "9p.h"
  43 #include "v9fs_vfs.h"
  44 #include "fid.h"
  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 *v9fid, *fid;
  57         struct v9fs_fcall *fcall = NULL;
  58         int open_mode = 0;
  59         unsigned int iounit = 0;
  60         int newfid = -1;
  61         long result = -1;
  62
  63         dprintk(DEBUG_VFS, "inode: %p file: %p \n", inode, file);
  64
  65         v9fid = v9fs_fid_get_created(file->f_dentry);
  66         if (!v9fid)
  67                 v9fid = v9fs_fid_lookup(file->f_dentry);
  68
  69         if (!v9fid) {
  70                 dprintk(DEBUG_ERROR, "Couldn't resolve fid from dentry\n");
  71                 return -EBADF;
  72         }
  73
  74         if (!v9fid->fidcreate) {
  75                 fid = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
  76                 if (fid == NULL) {
  77                         dprintk(DEBUG_ERROR, "Out of Memory\n");
  78                         return -ENOMEM;
  79                 }
  80
  81                 fid->fidopen = 0;
  82                 fid->fidcreate = 0;
  83                 fid->fidclunked = 0;
  84                 fid->iounit = 0;
  85                 fid->v9ses = v9ses;
  86
  87                 newfid = v9fs_get_idpool(&v9ses->fidpool);
  88                 if (newfid < 0) {
  89                         eprintk(KERN_WARNING, "newfid fails!\n");
  90                         return -ENOSPC;
  91                 }
  92
  93                 result =
  94                     v9fs_t_walk(v9ses, v9fid->fid, newfid, NULL, NULL);
  95
  96                 if (result < 0) {
  97                         v9fs_put_idpool(newfid, &v9ses->fidpool);
  98                         dprintk(DEBUG_ERROR, "rewalk didn't work\n");
  99                         return -EBADF;
 100                 }
 101
 102                 fid->fid = newfid;
 103                 v9fid = fid;
 104                 /* TODO: do special things for O_EXCL, O_NOFOLLOW, O_SYNC */
 105                 /* translate open mode appropriately */
 106                 open_mode = file->f_flags & 0x3;
 107
 108                 if (file->f_flags & O_EXCL)
 109                         open_mode |= V9FS_OEXCL;
 110
 111                 if (v9ses->extended) {
 112                         if (file->f_flags & O_TRUNC)
 113                                 open_mode |= V9FS_OTRUNC;
 114
 115                         if (file->f_flags & O_APPEND)
 116                                 open_mode |= V9FS_OAPPEND;
 117                 }
 118
 119                 result = v9fs_t_open(v9ses, newfid, open_mode, &fcall);
 120                 if (result < 0) {
 121                         dprintk(DEBUG_ERROR,
 122                                 "open failed, open_mode 0x%x: %s\n", open_mode,
 123                                 FCALL_ERROR(fcall));
 124                         kfree(fcall);
 125                         return result;
 126                 }
 127
 128                 iounit = fcall->params.ropen.iounit;
 129                 kfree(fcall);
 130         } else {
 131                 /* create case */
 132                 newfid = v9fid->fid;
 133                 iounit = v9fid->iounit;
 134                 v9fid->fidcreate = 0;
 135         }
 136
 137         file->private_data = v9fid;
 138
 139         v9fid->rdir_pos = 0;
 140         v9fid->rdir_fcall = NULL;
 141         v9fid->fidopen = 1;
 142         v9fid->filp = file;
 143         v9fid->iounit = iounit;
 144
 145         return 0;
 146 }
 147
 148 /**
 149  * v9fs_file_lock - lock a file (or directory)
 150  * @inode: inode to be opened
 151  * @file: file being opened
 152  *
 153  * XXX - this looks like a local only lock, we should extend into 9P
 154  *       by using open exclusive
 155  */
 156
 157 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 158 {
 159         int res = 0;
 160         struct inode *inode = filp->f_dentry->d_inode;
 161
 162         dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 163
 164         /* No mandatory locks */
 165         if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
 166                 return -ENOLCK;
 167
 168         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 169                 filemap_fdatawrite(inode->i_mapping);
 170                 filemap_fdatawait(inode->i_mapping);
 171                 invalidate_inode_pages(&inode->i_data);
 172         }
 173
 174         return res;
 175 }
 176
 177 /**
 178  * v9fs_file_read - read from a file
 179  * @filep: file pointer to read
 180  * @data: data buffer to read data into
 181  * @count: size of buffer
 182  * @offset: offset at which to read data
 183  *
 184  */
 185 static ssize_t
 186 v9fs_file_read(struct file *filp, char __user * data, size_t count,
 187                loff_t * offset)
 188 {
 189         struct inode *inode = filp->f_dentry->d_inode;
 190         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 191         struct v9fs_fid *v9f = filp->private_data;
 192         struct v9fs_fcall *fcall = NULL;
 193         int fid = v9f->fid;
 194         int rsize = 0;
 195         int result = 0;
 196         int total = 0;
 197         int n;
 198
 199         dprintk(DEBUG_VFS, "\n");
 200
 201         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 202         if (v9f->iounit != 0 && rsize > v9f->iounit)
 203                 rsize = v9f->iounit;
 204
 205         do {
 206                 if (count < rsize)
 207                         rsize = count;
 208
 209                 result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
 210
 211                 if (result < 0) {
 212                         printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
 213                                result);
 214
 215                         kfree(fcall);
 216                         return total;
 217                 } else
 218                         *offset += result;
 219
 220                 n = copy_to_user(data, fcall->params.rread.data, result);
 221                 if (n) {
 222                         dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
 223                         kfree(fcall);
 224                         return -EFAULT;
 225                 }
 226
 227                 count -= result;
 228                 data += result;
 229                 total += result;
 230
 231                 kfree(fcall);
 232
 233                 if (result < rsize)
 234                         break;
 235         } while (count);
 236
 237         return total;
 238 }
 239
 240 /**
 241  * v9fs_file_write - write to a file
 242  * @filep: file pointer to write
 243  * @data: data buffer to write data from
 244  * @count: size of buffer
 245  * @offset: offset at which to write data
 246  *
 247  */
 248
 249 static ssize_t
 250 v9fs_file_write(struct file *filp, const char __user * data,
 251                 size_t count, loff_t * offset)
 252 {
 253         struct inode *inode = filp->f_dentry->d_inode;
 254         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 255         struct v9fs_fid *v9fid = filp->private_data;
 256         struct v9fs_fcall *fcall;
 257         int fid = v9fid->fid;
 258         int result = -EIO;
 259         int rsize = 0;
 260         int total = 0;
 261         char *buf;
 262
 263         dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
 264                 (int)*offset);
 265         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 266         if (v9fid->iounit != 0 && rsize > v9fid->iounit)
 267                 rsize = v9fid->iounit;
 268
 269         buf = kmalloc(v9ses->maxdata - V9FS_IOHDRSZ, GFP_KERNEL);
 270         if (!buf)
 271                 return -ENOMEM;
 272
 273         do {
 274                 if (count < rsize)
 275                         rsize = count;
 276
 277                 result = copy_from_user(buf, data, rsize);
 278                 if (result) {
 279                         dprintk(DEBUG_ERROR, "Problem copying from user\n");
 280                         kfree(buf);
 281                         return -EFAULT;
 282                 }
 283
 284                 dump_data(buf, rsize);
 285                 result = v9fs_t_write(v9ses, fid, *offset, rsize, buf, &fcall);
 286                 if (result < 0) {
 287                         eprintk(KERN_ERR, "error while writing: %s(%d)\n",
 288                                 FCALL_ERROR(fcall), result);
 289                         kfree(fcall);
 290                         kfree(buf);
 291                         return result;
 292                 } else
 293                         *offset += result;
 294
 295                 kfree(fcall);
 296                 fcall = NULL;
 297
 298                 if (result != rsize) {
 299                         eprintk(KERN_ERR,
 300                                 "short write: v9fs_t_write returned %d\n",
 301                                 result);
 302                         break;
 303                 }
 304
 305                 count -= result;
 306                 data += result;
 307                 total += result;
 308         } while (count);
 309
 310         kfree(buf);
 311         return total;
 312 }
 313
 314 struct file_operations v9fs_file_operations = {
 315         .llseek = generic_file_llseek,
 316         .read = v9fs_file_read,
 317         .write = v9fs_file_write,
 318         .open = v9fs_file_open,
 319         .release = v9fs_dir_release,
 320         .lock = v9fs_file_lock,
 321 };