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 = v9fs_fid_lookup(file->f_dentry, FID_WALK);
  57         struct v9fs_fid *v9newfid = NULL;
  58         struct v9fs_fcall *fcall = NULL;
  59         int open_mode = 0;
  60         unsigned int iounit = 0;
  61         int newfid = -1;
  62         long result = -1;
  63
  64         dprintk(DEBUG_VFS, "inode: %p file: %p v9fid= %p\n", inode, file,
  65                 v9fid);
  66
  67         if (!v9fid) {
  68                 struct dentry *dentry = file->f_dentry;
  69                 dprintk(DEBUG_ERROR, "Couldn't resolve fid from dentry\n");
  70
  71                 /* XXX - some duplication from lookup, generalize later */
  72                 /* basically vfs_lookup is too heavy weight */
  73                 v9fid = v9fs_fid_lookup(file->f_dentry, FID_OP);
  74                 if (!v9fid)
  75                         return -EBADF;
  76
  77                 v9fid = v9fs_fid_lookup(dentry->d_parent, FID_WALK);
  78                 if (!v9fid)
  79                         return -EBADF;
  80
  81                 newfid = v9fs_get_idpool(&v9ses->fidpool);
  82                 if (newfid < 0) {
  83                         eprintk(KERN_WARNING, "newfid fails!\n");
  84                         return -ENOSPC;
  85                 }
  86
  87                 result =
  88                     v9fs_t_walk(v9ses, v9fid->fid, newfid,
  89                                 (char *)file->f_dentry->d_name.name, NULL);
  90                 if (result < 0) {
  91                         v9fs_put_idpool(newfid, &v9ses->fidpool);
  92                         dprintk(DEBUG_ERROR, "rewalk didn't work\n");
  93                         return -EBADF;
  94                 }
  95
  96                 v9fid = v9fs_fid_create(dentry);
  97                 if (v9fid == NULL) {
  98                         dprintk(DEBUG_ERROR, "couldn't insert\n");
  99                         return -ENOMEM;
 100                 }
 101                 v9fid->fid = newfid;
 102         }
 103
 104         if (v9fid->fidcreate) {
 105                 /* create case */
 106                 newfid = v9fid->fid;
 107                 iounit = v9fid->iounit;
 108                 v9fid->fidcreate = 0;
 109         } else {
 110                 if (!S_ISDIR(inode->i_mode))
 111                         newfid = v9fid->fid;
 112                 else {
 113                         newfid = v9fs_get_idpool(&v9ses->fidpool);
 114                         if (newfid < 0) {
 115                                 eprintk(KERN_WARNING, "allocation failed\n");
 116                                 return -ENOSPC;
 117                         }
 118                         /* This would be a somewhat critical clone */
 119                         result =
 120                             v9fs_t_walk(v9ses, v9fid->fid, newfid, NULL,
 121                                         &fcall);
 122                         if (result < 0) {
 123                                 dprintk(DEBUG_ERROR, "clone error: %s\n",
 124                                         FCALL_ERROR(fcall));
 125                                 kfree(fcall);
 126                                 return result;
 127                         }
 128
 129                         v9newfid = v9fs_fid_create(file->f_dentry);
 130                         v9newfid->fid = newfid;
 131                         v9newfid->qid = v9fid->qid;
 132                         v9newfid->iounit = v9fid->iounit;
 133                         v9newfid->fidopen = 0;
 134                         v9newfid->fidclunked = 0;
 135                         v9newfid->v9ses = v9ses;
 136                         v9fid = v9newfid;
 137                         kfree(fcall);
 138                 }
 139
 140                 /* TODO: do special things for O_EXCL, O_NOFOLLOW, O_SYNC */
 141                 /* translate open mode appropriately */
 142                 open_mode = file->f_flags & 0x3;
 143
 144                 if (file->f_flags & O_EXCL)
 145                         open_mode |= V9FS_OEXCL;
 146
 147                 if (v9ses->extended) {
 148                         if (file->f_flags & O_TRUNC)
 149                                 open_mode |= V9FS_OTRUNC;
 150
 151                         if (file->f_flags & O_APPEND)
 152                                 open_mode |= V9FS_OAPPEND;
 153                 }
 154
 155                 result = v9fs_t_open(v9ses, newfid, open_mode, &fcall);
 156                 if (result < 0) {
 157                         dprintk(DEBUG_ERROR,
 158                                 "open failed, open_mode 0x%x: %s\n", open_mode,
 159                                 FCALL_ERROR(fcall));
 160                         kfree(fcall);
 161                         return result;
 162                 }
 163
 164                 iounit = fcall->params.ropen.iounit;
 165                 kfree(fcall);
 166         }
 167
 168
 169         file->private_data = v9fid;
 170
 171         v9fid->rdir_pos = 0;
 172         v9fid->rdir_fcall = NULL;
 173         v9fid->fidopen = 1;
 174         v9fid->filp = file;
 175         v9fid->iounit = iounit;
 176
 177         return 0;
 178 }
 179
 180 /**
 181  * v9fs_file_lock - lock a file (or directory)
 182  * @inode: inode to be opened
 183  * @file: file being opened
 184  *
 185  * XXX - this looks like a local only lock, we should extend into 9P
 186  *       by using open exclusive
 187  */
 188
 189 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 190 {
 191         int res = 0;
 192         struct inode *inode = filp->f_dentry->d_inode;
 193
 194         dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 195
 196         /* No mandatory locks */
 197         if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
 198                 return -ENOLCK;
 199
 200         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 201                 filemap_fdatawrite(inode->i_mapping);
 202                 filemap_fdatawait(inode->i_mapping);
 203                 invalidate_inode_pages(&inode->i_data);
 204         }
 205
 206         return res;
 207 }
 208
 209 /**
 210  * v9fs_read - read from a file (internal)
 211  * @filep: file pointer to read
 212  * @data: data buffer to read data into
 213  * @count: size of buffer
 214  * @offset: offset at which to read data
 215  *
 216  */
 217
 218 static ssize_t
 219 v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset)
 220 {
 221         struct inode *inode = filp->f_dentry->d_inode;
 222         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 223         struct v9fs_fid *v9f = filp->private_data;
 224         struct v9fs_fcall *fcall = NULL;
 225         int fid = v9f->fid;
 226         int rsize = 0;
 227         int result = 0;
 228         int total = 0;
 229
 230         dprintk(DEBUG_VFS, "\n");
 231
 232         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 233         if (v9f->iounit != 0 && rsize > v9f->iounit)
 234                 rsize = v9f->iounit;
 235
 236         do {
 237                 if (count < rsize)
 238                         rsize = count;
 239
 240                 result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
 241
 242                 if (result < 0) {
 243                         printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
 244                                result);
 245
 246                         kfree(fcall);
 247                         return total;
 248                 } else
 249                         *offset += result;
 250
 251                 /* XXX - extra copy */
 252                 memcpy(buffer, fcall->params.rread.data, result);
 253                 count -= result;
 254                 buffer += result;
 255                 total += result;
 256
 257                 kfree(fcall);
 258
 259                 if (result < rsize)
 260                         break;
 261         } while (count);
 262
 263         return total;
 264 }
 265
 266 /**
 267  * v9fs_file_read - read from a file
 268  * @filep: file pointer to read
 269  * @data: data buffer to read data into
 270  * @count: size of buffer
 271  * @offset: offset at which to read data
 272  *
 273  */
 274
 275 static ssize_t
 276 v9fs_file_read(struct file *filp, char __user * data, size_t count,
 277                loff_t * offset)
 278 {
 279         int retval = -1;
 280         int ret = 0;
 281         char *buffer;
 282
 283         buffer = kmalloc(count, GFP_KERNEL);
 284         if (!buffer)
 285                 return -ENOMEM;
 286
 287         retval = v9fs_read(filp, buffer, count, offset);
 288         if (retval > 0) {
 289                 if ((ret = copy_to_user(data, buffer, retval)) != 0) {
 290                         dprintk(DEBUG_ERROR, "Problem copying to user %d\n",
 291                                 ret);
 292                         retval = ret;
 293                 }
 294         }
 295
 296         kfree(buffer);
 297
 298         return retval;
 299 }
 300
 301 /**
 302  * v9fs_write - write to a file
 303  * @filep: file pointer to write
 304  * @data: data buffer to write data from
 305  * @count: size of buffer
 306  * @offset: offset at which to write data
 307  *
 308  */
 309
 310 static ssize_t
 311 v9fs_write(struct file *filp, char *buffer, size_t count, loff_t * offset)
 312 {
 313         struct inode *inode = filp->f_dentry->d_inode;
 314         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 315         struct v9fs_fid *v9fid = filp->private_data;
 316         struct v9fs_fcall *fcall;
 317         int fid = v9fid->fid;
 318         int result = -EIO;
 319         int rsize = 0;
 320         int total = 0;
 321
 322         dprintk(DEBUG_VFS, "data %p count %d offset %x\n", buffer, (int)count,
 323                 (int)*offset);
 324         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 325         if (v9fid->iounit != 0 && rsize > v9fid->iounit)
 326                 rsize = v9fid->iounit;
 327
 328         dump_data(buffer, count);
 329
 330         do {
 331                 if (count < rsize)
 332                         rsize = count;
 333
 334                 result =
 335                     v9fs_t_write(v9ses, fid, *offset, rsize, buffer, &fcall);
 336                 if (result < 0) {
 337                         eprintk(KERN_ERR, "error while writing: %s(%d)\n",
 338                                 FCALL_ERROR(fcall), result);
 339                         kfree(fcall);
 340                         return result;
 341                 } else
 342                         *offset += result;
 343
 344                 kfree(fcall);
 345
 346                 if (result != rsize) {
 347                         eprintk(KERN_ERR,
 348                                 "short write: v9fs_t_write returned %d\n",
 349                                 result);
 350                         break;
 351                 }
 352
 353                 count -= result;
 354                 buffer += result;
 355                 total += result;
 356         } while (count);
 357
 358         return total;
 359 }
 360
 361 /**
 362  * v9fs_file_write - write to a file
 363  * @filep: file pointer to write
 364  * @data: data buffer to write data from
 365  * @count: size of buffer
 366  * @offset: offset at which to write data
 367  *
 368  */
 369
 370 static ssize_t
 371 v9fs_file_write(struct file *filp, const char __user * data,
 372                 size_t count, loff_t * offset)
 373 {
 374         int ret = -1;
 375         char *buffer;
 376
 377         buffer = kmalloc(count, GFP_KERNEL);
 378         if (buffer == NULL)
 379                 return -ENOMEM;
 380
 381         ret = copy_from_user(buffer, data, count);
 382         if (ret) {
 383                 dprintk(DEBUG_ERROR, "Problem copying from user\n");
 384                 ret = -EFAULT;
 385         } else {
 386                 ret = v9fs_write(filp, buffer, count, offset);
 387         }
 388
 389         kfree(buffer);
 390
 391         return ret;
 392 }
 393
 394 struct file_operations v9fs_file_operations = {
 395         .llseek = generic_file_llseek,
 396         .read = v9fs_file_read,
 397         .write = v9fs_file_write,
 398         .open = v9fs_file_open,
 399         .release = v9fs_dir_release,
 400         .lock = v9fs_file_lock,
 401 };