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                         PRINT_FCALL_ERROR("open failed", fcall);
 122                         kfree(fcall);
 123                         return result;
 124                 }
 125
 126                 iounit = fcall->params.ropen.iounit;
 127                 kfree(fcall);
 128         } else {
 129                 /* create case */
 130                 newfid = v9fid->fid;
 131                 iounit = v9fid->iounit;
 132                 v9fid->fidcreate = 0;
 133         }
 134
 135         file->private_data = v9fid;
 136
 137         v9fid->rdir_pos = 0;
 138         v9fid->rdir_fcall = NULL;
 139         v9fid->fidopen = 1;
 140         v9fid->filp = file;
 141         v9fid->iounit = iounit;
 142
 143         return 0;
 144 }
 145
 146 /**
 147  * v9fs_file_lock - lock a file (or directory)
 148  * @inode: inode to be opened
 149  * @file: file being opened
 150  *
 151  * XXX - this looks like a local only lock, we should extend into 9P
 152  *       by using open exclusive
 153  */
 154
 155 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 156 {
 157         int res = 0;
 158         struct inode *inode = filp->f_dentry->d_inode;
 159
 160         dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 161
 162         /* No mandatory locks */
 163         if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
 164                 return -ENOLCK;
 165
 166         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 167                 filemap_write_and_wait(inode->i_mapping);
 168                 invalidate_inode_pages(&inode->i_data);
 169         }
 170
 171         return res;
 172 }
 173
 174 /**
 175  * v9fs_file_read - read from a file
 176  * @filep: file pointer to read
 177  * @data: data buffer to read data into
 178  * @count: size of buffer
 179  * @offset: offset at which to read data
 180  *
 181  */
 182 static ssize_t
 183 v9fs_file_read(struct file *filp, char __user * data, size_t count,
 184                loff_t * offset)
 185 {
 186         struct inode *inode = filp->f_dentry->d_inode;
 187         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 188         struct v9fs_fid *v9f = filp->private_data;
 189         struct v9fs_fcall *fcall = NULL;
 190         int fid = v9f->fid;
 191         int rsize = 0;
 192         int result = 0;
 193         int total = 0;
 194         int n;
 195
 196         dprintk(DEBUG_VFS, "\n");
 197
 198         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 199         if (v9f->iounit != 0 && rsize > v9f->iounit)
 200                 rsize = v9f->iounit;
 201
 202         do {
 203                 if (count < rsize)
 204                         rsize = count;
 205
 206                 result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
 207
 208                 if (result < 0) {
 209                         printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
 210                                result);
 211
 212                         kfree(fcall);
 213                         return total;
 214                 } else
 215                         *offset += result;
 216
 217                 n = copy_to_user(data, fcall->params.rread.data, result);
 218                 if (n) {
 219                         dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
 220                         kfree(fcall);
 221                         return -EFAULT;
 222                 }
 223
 224                 count -= result;
 225                 data += result;
 226                 total += result;
 227
 228                 kfree(fcall);
 229
 230                 if (result < rsize)
 231                         break;
 232         } while (count);
 233
 234         return total;
 235 }
 236
 237 /**
 238  * v9fs_file_write - write to a file
 239  * @filep: file pointer to write
 240  * @data: data buffer to write data from
 241  * @count: size of buffer
 242  * @offset: offset at which to write data
 243  *
 244  */
 245
 246 static ssize_t
 247 v9fs_file_write(struct file *filp, const char __user * data,
 248                 size_t count, loff_t * offset)
 249 {
 250         struct inode *inode = filp->f_dentry->d_inode;
 251         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 252         struct v9fs_fid *v9fid = filp->private_data;
 253         struct v9fs_fcall *fcall;
 254         int fid = v9fid->fid;
 255         int result = -EIO;
 256         int rsize = 0;
 257         int total = 0;
 258
 259         dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
 260                 (int)*offset);
 261         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 262         if (v9fid->iounit != 0 && rsize > v9fid->iounit)
 263                 rsize = v9fid->iounit;
 264
 265         do {
 266                 if (count < rsize)
 267                         rsize = count;
 268
 269                 result = v9fs_t_write(v9ses, fid, *offset, rsize, data, &fcall);
 270                 if (result < 0) {
 271                         PRINT_FCALL_ERROR("error while writing", fcall);
 272                         kfree(fcall);
 273                         return result;
 274                 } else
 275                         *offset += result;
 276
 277                 kfree(fcall);
 278                 fcall = NULL;
 279
 280                 if (result != rsize) {
 281                         eprintk(KERN_ERR,
 282                                 "short write: v9fs_t_write returned %d\n",
 283                                 result);
 284                         break;
 285                 }
 286
 287                 count -= result;
 288                 data += result;
 289                 total += result;
 290         } while (count);
 291
 292         if(inode->i_mapping->nrpages)
 293                 invalidate_inode_pages2(inode->i_mapping);
 294
 295         return total;
 296 }
 297
 298 struct file_operations v9fs_file_operations = {
 299         .llseek = generic_file_llseek,
 300         .read = v9fs_file_read,
 301         .write = v9fs_file_write,
 302         .open = v9fs_file_open,
 303         .release = v9fs_dir_release,
 304         .lock = v9fs_file_lock,
 305         .mmap = generic_file_mmap,
 306 };