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/file.h>
  30 #include <linux/stat.h>
  31 #include <linux/string.h>
  32 #include <linux/smp_lock.h>
  33 #include <linux/inet.h>
  34 #include <linux/list.h>
  35 #include <asm/uaccess.h>
  36 #include <linux/idr.h>
  37
  38 #include "debug.h"
  39 #include "v9fs.h"
  40 #include "9p.h"
  41 #include "v9fs_vfs.h"
  42 #include "fid.h"
  43
  44 /**
  45  * v9fs_file_open - open a file (or directory)
  46  * @inode: inode to be opened
  47  * @file: file being opened
  48  *
  49  */
  50
  51 int v9fs_file_open(struct inode *inode, struct file *file)
  52 {
  53         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
  54         struct v9fs_fid *vfid;
  55         struct v9fs_fcall *fcall = NULL;
  56         int omode;
  57         int fid = V9FS_NOFID;
  58         int err;
  59
  60         dprintk(DEBUG_VFS, "inode: %p file: %p \n", inode, file);
  61
  62         vfid = v9fs_fid_lookup(file->f_dentry);
  63         if (!vfid) {
  64                 dprintk(DEBUG_ERROR, "Couldn't resolve fid from dentry\n");
  65                 return -EBADF;
  66         }
  67
  68         fid = v9fs_get_idpool(&v9ses->fidpool);
  69         if (fid < 0) {
  70                 eprintk(KERN_WARNING, "newfid fails!\n");
  71                 return -ENOSPC;
  72         }
  73
  74         err = v9fs_t_walk(v9ses, vfid->fid, fid, NULL, &fcall);
  75         if (err < 0) {
  76                 dprintk(DEBUG_ERROR, "rewalk didn't work\n");
  77                 if (fcall && fcall->id == RWALK)
  78                         goto clunk_fid;
  79                 else {
  80                         v9fs_put_idpool(fid, &v9ses->fidpool);
  81                         goto free_fcall;
  82                 }
  83         }
  84         kfree(fcall);
  85
  86         /* TODO: do special things for O_EXCL, O_NOFOLLOW, O_SYNC */
  87         /* translate open mode appropriately */
  88         omode = v9fs_uflags2omode(file->f_flags);
  89         err = v9fs_t_open(v9ses, fid, omode, &fcall);
  90         if (err < 0) {
  91                 PRINT_FCALL_ERROR("open failed", fcall);
  92                 goto clunk_fid;
  93         }
  94
  95         vfid = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
  96         if (vfid == NULL) {
  97                 dprintk(DEBUG_ERROR, "out of memory\n");
  98                 err = -ENOMEM;
  99                 goto clunk_fid;
 100         }
 101
 102         file->private_data = vfid;
 103         vfid->fid = fid;
 104         vfid->fidopen = 1;
 105         vfid->fidclunked = 0;
 106         vfid->iounit = fcall->params.ropen.iounit;
 107         vfid->rdir_pos = 0;
 108         vfid->rdir_fcall = NULL;
 109         vfid->filp = file;
 110         kfree(fcall);
 111
 112         return 0;
 113
 114 clunk_fid:
 115         v9fs_t_clunk(v9ses, fid);
 116
 117 free_fcall:
 118         kfree(fcall);
 119
 120         return err;
 121 }
 122
 123 /**
 124  * v9fs_file_lock - lock a file (or directory)
 125  * @inode: inode to be opened
 126  * @file: file being opened
 127  *
 128  * XXX - this looks like a local only lock, we should extend into 9P
 129  *       by using open exclusive
 130  */
 131
 132 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 133 {
 134         int res = 0;
 135         struct inode *inode = filp->f_dentry->d_inode;
 136
 137         dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 138
 139         /* No mandatory locks */
 140         if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
 141                 return -ENOLCK;
 142
 143         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 144                 filemap_write_and_wait(inode->i_mapping);
 145                 invalidate_inode_pages(&inode->i_data);
 146         }
 147
 148         return res;
 149 }
 150
 151 /**
 152  * v9fs_file_read - read from a file
 153  * @filep: file pointer to read
 154  * @data: data buffer to read data into
 155  * @count: size of buffer
 156  * @offset: offset at which to read data
 157  *
 158  */
 159 static ssize_t
 160 v9fs_file_read(struct file *filp, char __user * data, size_t count,
 161                loff_t * offset)
 162 {
 163         struct inode *inode = filp->f_dentry->d_inode;
 164         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 165         struct v9fs_fid *v9f = filp->private_data;
 166         struct v9fs_fcall *fcall = NULL;
 167         int fid = v9f->fid;
 168         int rsize = 0;
 169         int result = 0;
 170         int total = 0;
 171         int n;
 172
 173         dprintk(DEBUG_VFS, "\n");
 174
 175         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 176         if (v9f->iounit != 0 && rsize > v9f->iounit)
 177                 rsize = v9f->iounit;
 178
 179         do {
 180                 if (count < rsize)
 181                         rsize = count;
 182
 183                 result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
 184
 185                 if (result < 0) {
 186                         printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
 187                                result);
 188
 189                         kfree(fcall);
 190                         return total;
 191                 } else
 192                         *offset += result;
 193
 194                 n = copy_to_user(data, fcall->params.rread.data, result);
 195                 if (n) {
 196                         dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
 197                         kfree(fcall);
 198                         return -EFAULT;
 199                 }
 200
 201                 count -= result;
 202                 data += result;
 203                 total += result;
 204
 205                 kfree(fcall);
 206
 207                 if (result < rsize)
 208                         break;
 209         } while (count);
 210
 211         return total;
 212 }
 213
 214 /**
 215  * v9fs_file_write - write to a file
 216  * @filep: file pointer to write
 217  * @data: data buffer to write data from
 218  * @count: size of buffer
 219  * @offset: offset at which to write data
 220  *
 221  */
 222
 223 static ssize_t
 224 v9fs_file_write(struct file *filp, const char __user * data,
 225                 size_t count, loff_t * offset)
 226 {
 227         struct inode *inode = filp->f_dentry->d_inode;
 228         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 229         struct v9fs_fid *v9fid = filp->private_data;
 230         struct v9fs_fcall *fcall;
 231         int fid = v9fid->fid;
 232         int result = -EIO;
 233         int rsize = 0;
 234         int total = 0;
 235
 236         dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
 237                 (int)*offset);
 238         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 239         if (v9fid->iounit != 0 && rsize > v9fid->iounit)
 240                 rsize = v9fid->iounit;
 241
 242         do {
 243                 if (count < rsize)
 244                         rsize = count;
 245
 246                 result = v9fs_t_write(v9ses, fid, *offset, rsize, data, &fcall);
 247                 if (result < 0) {
 248                         PRINT_FCALL_ERROR("error while writing", fcall);
 249                         kfree(fcall);
 250                         return result;
 251                 } else
 252                         *offset += result;
 253
 254                 kfree(fcall);
 255                 fcall = NULL;
 256
 257                 if (result != rsize) {
 258                         eprintk(KERN_ERR,
 259                                 "short write: v9fs_t_write returned %d\n",
 260                                 result);
 261                         break;
 262                 }
 263
 264                 count -= result;
 265                 data += result;
 266                 total += result;
 267         } while (count);
 268
 269                 invalidate_inode_pages2(inode->i_mapping);
 270         return total;
 271 }
 272
 273 const struct file_operations v9fs_file_operations = {
 274         .llseek = generic_file_llseek,
 275         .read = v9fs_file_read,
 276         .write = v9fs_file_write,
 277         .open = v9fs_file_open,
 278         .release = v9fs_dir_release,
 279         .lock = v9fs_file_lock,
 280         .mmap = generic_file_mmap,
 281 };