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/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 /**
  46  * v9fs_file_open - open a file (or directory)
  47  * @inode: inode to be opened
  48  * @file: file being opened
  49  *
  50  */
  51
  52 int v9fs_file_open(struct inode *inode, struct file *file)
  53 {
  54         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
  55         struct v9fs_fid *v9fid, *fid;
  56         struct v9fs_fcall *fcall = NULL;
  57         int open_mode = 0;
  58         unsigned int iounit = 0;
  59         int newfid = -1;
  60         long result = -1;
  61
  62         dprintk(DEBUG_VFS, "inode: %p file: %p \n", inode, file);
  63
  64         v9fid = v9fs_fid_get_created(file->f_dentry);
  65         if (!v9fid)
  66                 v9fid = v9fs_fid_lookup(file->f_dentry);
  67
  68         if (!v9fid) {
  69                 dprintk(DEBUG_ERROR, "Couldn't resolve fid from dentry\n");
  70                 return -EBADF;
  71         }
  72
  73         if (!v9fid->fidcreate) {
  74                 fid = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
  75                 if (fid == NULL) {
  76                         dprintk(DEBUG_ERROR, "Out of Memory\n");
  77                         return -ENOMEM;
  78                 }
  79
  80                 fid->fidopen = 0;
  81                 fid->fidcreate = 0;
  82                 fid->fidclunked = 0;
  83                 fid->iounit = 0;
  84                 fid->v9ses = v9ses;
  85
  86                 newfid = v9fs_get_idpool(&v9ses->fidpool);
  87                 if (newfid < 0) {
  88                         eprintk(KERN_WARNING, "newfid fails!\n");
  89                         return -ENOSPC;
  90                 }
  91
  92                 result =
  93                     v9fs_t_walk(v9ses, v9fid->fid, newfid, NULL, NULL);
  94
  95                 if (result < 0) {
  96                         v9fs_put_idpool(newfid, &v9ses->fidpool);
  97                         dprintk(DEBUG_ERROR, "rewalk didn't work\n");
  98                         return -EBADF;
  99                 }
 100
 101                 fid->fid = newfid;
 102                 v9fid = fid;
 103                 /* TODO: do special things for O_EXCL, O_NOFOLLOW, O_SYNC */
 104                 /* translate open mode appropriately */
 105                 open_mode = file->f_flags & 0x3;
 106
 107                 if (file->f_flags & O_EXCL)
 108                         open_mode |= V9FS_OEXCL;
 109
 110                 if (v9ses->extended) {
 111                         if (file->f_flags & O_TRUNC)
 112                                 open_mode |= V9FS_OTRUNC;
 113
 114                         if (file->f_flags & O_APPEND)
 115                                 open_mode |= V9FS_OAPPEND;
 116                 }
 117
 118                 result = v9fs_t_open(v9ses, newfid, open_mode, &fcall);
 119                 if (result < 0) {
 120                         dprintk(DEBUG_ERROR,
 121                                 "open failed, open_mode 0x%x: %s\n", open_mode,
 122                                 FCALL_ERROR(fcall));
 123                         kfree(fcall);
 124                         return result;
 125                 }
 126
 127                 iounit = fcall->params.ropen.iounit;
 128                 kfree(fcall);
 129         } else {
 130                 /* create case */
 131                 newfid = v9fid->fid;
 132                 iounit = v9fid->iounit;
 133                 v9fid->fidcreate = 0;
 134         }
 135
 136         file->private_data = v9fid;
 137
 138         v9fid->rdir_pos = 0;
 139         v9fid->rdir_fcall = NULL;
 140         v9fid->fidopen = 1;
 141         v9fid->filp = file;
 142         v9fid->iounit = iounit;
 143
 144         return 0;
 145 }
 146
 147 /**
 148  * v9fs_file_lock - lock a file (or directory)
 149  * @inode: inode to be opened
 150  * @file: file being opened
 151  *
 152  * XXX - this looks like a local only lock, we should extend into 9P
 153  *       by using open exclusive
 154  */
 155
 156 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 157 {
 158         int res = 0;
 159         struct inode *inode = filp->f_dentry->d_inode;
 160
 161         dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 162
 163         /* No mandatory locks */
 164         if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
 165                 return -ENOLCK;
 166
 167         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 168                 filemap_fdatawrite(inode->i_mapping);
 169                 filemap_fdatawait(inode->i_mapping);
 170                 invalidate_inode_pages(&inode->i_data);
 171         }
 172
 173         return res;
 174 }
 175
 176 /**
 177  * v9fs_file_read - read from a file
 178  * @filep: file pointer to read
 179  * @data: data buffer to read data into
 180  * @count: size of buffer
 181  * @offset: offset at which to read data
 182  *
 183  */
 184 static ssize_t
 185 v9fs_file_read(struct file *filp, char __user * data, size_t count,
 186                loff_t * offset)
 187 {
 188         struct inode *inode = filp->f_dentry->d_inode;
 189         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 190         struct v9fs_fid *v9f = filp->private_data;
 191         struct v9fs_fcall *fcall = NULL;
 192         int fid = v9f->fid;
 193         int rsize = 0;
 194         int result = 0;
 195         int total = 0;
 196         int n;
 197
 198         dprintk(DEBUG_VFS, "\n");
 199
 200         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 201         if (v9f->iounit != 0 && rsize > v9f->iounit)
 202                 rsize = v9f->iounit;
 203
 204         do {
 205                 if (count < rsize)
 206                         rsize = count;
 207
 208                 result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
 209
 210                 if (result < 0) {
 211                         printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
 212                                result);
 213
 214                         kfree(fcall);
 215                         return total;
 216                 } else
 217                         *offset += result;
 218
 219                 n = copy_to_user(data, fcall->params.rread.data, result);
 220                 if (n) {
 221                         dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
 222                         kfree(fcall);
 223                         return -EFAULT;
 224                 }
 225
 226                 count -= result;
 227                 data += result;
 228                 total += result;
 229
 230                 kfree(fcall);
 231
 232                 if (result < rsize)
 233                         break;
 234         } while (count);
 235
 236         return total;
 237 }
 238
 239 /**
 240  * v9fs_file_write - write to a file
 241  * @filep: file pointer to write
 242  * @data: data buffer to write data from
 243  * @count: size of buffer
 244  * @offset: offset at which to write data
 245  *
 246  */
 247
 248 static ssize_t
 249 v9fs_file_write(struct file *filp, const char __user * data,
 250                 size_t count, loff_t * offset)
 251 {
 252         struct inode *inode = filp->f_dentry->d_inode;
 253         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 254         struct v9fs_fid *v9fid = filp->private_data;
 255         struct v9fs_fcall *fcall;
 256         int fid = v9fid->fid;
 257         int result = -EIO;
 258         int rsize = 0;
 259         int total = 0;
 260         char *buf;
 261
 262         dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
 263                 (int)*offset);
 264         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 265         if (v9fid->iounit != 0 && rsize > v9fid->iounit)
 266                 rsize = v9fid->iounit;
 267
 268         buf = kmalloc(v9ses->maxdata - V9FS_IOHDRSZ, GFP_KERNEL);
 269         if (!buf)
 270                 return -ENOMEM;
 271
 272         do {
 273                 if (count < rsize)
 274                         rsize = count;
 275
 276                 result = copy_from_user(buf, data, rsize);
 277                 if (result) {
 278                         dprintk(DEBUG_ERROR, "Problem copying from user\n");
 279                         kfree(buf);
 280                         return -EFAULT;
 281                 }
 282
 283                 dump_data(buf, rsize);
 284                 result = v9fs_t_write(v9ses, fid, *offset, rsize, buf, &fcall);
 285                 if (result < 0) {
 286                         eprintk(KERN_ERR, "error while writing: %s(%d)\n",
 287                                 FCALL_ERROR(fcall), result);
 288                         kfree(fcall);
 289                         kfree(buf);
 290                         return result;
 291                 } else
 292                         *offset += result;
 293
 294                 kfree(fcall);
 295                 fcall = NULL;
 296
 297                 if (result != rsize) {
 298                         eprintk(KERN_ERR,
 299                                 "short write: v9fs_t_write returned %d\n",
 300                                 result);
 301                         break;
 302                 }
 303
 304                 count -= result;
 305                 data += result;
 306                 total += result;
 307         } while (count);
 308
 309         kfree(buf);
 310         return total;
 311 }
 312
 313 struct file_operations v9fs_file_operations = {
 314         .llseek = generic_file_llseek,
 315         .read = v9fs_file_read,
 316         .write = v9fs_file_write,
 317         .open = v9fs_file_open,
 318         .release = v9fs_dir_release,
 319         .lock = v9fs_file_lock,
 320 };