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 *vfid;
  57         struct v9fs_fcall *fcall = NULL;
  58         int omode;
  59         int fid = V9FS_NOFID;
  60         int err;
  61
  62         dprintk(DEBUG_VFS, "inode: %p file: %p \n", inode, file);
  63
  64         vfid = v9fs_fid_lookup(file->f_dentry);
  65         if (!vfid) {
  66                 dprintk(DEBUG_ERROR, "Couldn't resolve fid from dentry\n");
  67                 return -EBADF;
  68         }
  69
  70         fid = v9fs_get_idpool(&v9ses->fidpool);
  71         if (fid < 0) {
  72                         eprintk(KERN_WARNING, "newfid fails!\n");
  73                         return -ENOSPC;
  74                 }
  75
  76         err = v9fs_t_walk(v9ses, vfid->fid, fid, NULL, NULL);
  77         if (err < 0) {
  78                         dprintk(DEBUG_ERROR, "rewalk didn't work\n");
  79                 goto put_fid;
  80         }
  81
  82         vfid = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
  83         if (vfid == NULL) {
  84                 dprintk(DEBUG_ERROR, "out of memory\n");
  85                 goto clunk_fid;
  86                 }
  87
  88                 /* TODO: do special things for O_EXCL, O_NOFOLLOW, O_SYNC */
  89                 /* translate open mode appropriately */
  90         omode = v9fs_uflags2omode(file->f_flags);
  91         err = v9fs_t_open(v9ses, fid, omode, &fcall);
  92         if (err < 0) {
  93                 PRINT_FCALL_ERROR("open failed", fcall);
  94                 goto destroy_vfid;
  95         }
  96
  97         file->private_data = vfid;
  98         vfid->fid = fid;
  99         vfid->fidopen = 1;
 100         vfid->fidclunked = 0;
 101         vfid->iounit = fcall->params.ropen.iounit;
 102         vfid->rdir_pos = 0;
 103         vfid->rdir_fcall = NULL;
 104         vfid->filp = file;
 105         kfree(fcall);
 106
 107         return 0;
 108
 109 destroy_vfid:
 110         v9fs_fid_destroy(vfid);
 111
 112 clunk_fid:
 113         v9fs_t_clunk(v9ses, fid);
 114
 115 put_fid:
 116         v9fs_put_idpool(fid, &v9ses->fidpool);
 117                 kfree(fcall);
 118
 119         return err;
 120 }
 121
 122 /**
 123  * v9fs_file_lock - lock a file (or directory)
 124  * @inode: inode to be opened
 125  * @file: file being opened
 126  *
 127  * XXX - this looks like a local only lock, we should extend into 9P
 128  *       by using open exclusive
 129  */
 130
 131 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 132 {
 133         int res = 0;
 134         struct inode *inode = filp->f_dentry->d_inode;
 135
 136         dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 137
 138         /* No mandatory locks */
 139         if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
 140                 return -ENOLCK;
 141
 142         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 143                 filemap_write_and_wait(inode->i_mapping);
 144                 invalidate_inode_pages(&inode->i_data);
 145         }
 146
 147         return res;
 148 }
 149
 150 /**
 151  * v9fs_file_read - read from a file
 152  * @filep: file pointer to read
 153  * @data: data buffer to read data into
 154  * @count: size of buffer
 155  * @offset: offset at which to read data
 156  *
 157  */
 158 static ssize_t
 159 v9fs_file_read(struct file *filp, char __user * data, size_t count,
 160                loff_t * offset)
 161 {
 162         struct inode *inode = filp->f_dentry->d_inode;
 163         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 164         struct v9fs_fid *v9f = filp->private_data;
 165         struct v9fs_fcall *fcall = NULL;
 166         int fid = v9f->fid;
 167         int rsize = 0;
 168         int result = 0;
 169         int total = 0;
 170         int n;
 171
 172         dprintk(DEBUG_VFS, "\n");
 173
 174         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 175         if (v9f->iounit != 0 && rsize > v9f->iounit)
 176                 rsize = v9f->iounit;
 177
 178         do {
 179                 if (count < rsize)
 180                         rsize = count;
 181
 182                 result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
 183
 184                 if (result < 0) {
 185                         printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
 186                                result);
 187
 188                         kfree(fcall);
 189                         return total;
 190                 } else
 191                         *offset += result;
 192
 193                 n = copy_to_user(data, fcall->params.rread.data, result);
 194                 if (n) {
 195                         dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
 196                         kfree(fcall);
 197                         return -EFAULT;
 198                 }
 199
 200                 count -= result;
 201                 data += result;
 202                 total += result;
 203
 204                 kfree(fcall);
 205
 206                 if (result < rsize)
 207                         break;
 208         } while (count);
 209
 210         return total;
 211 }
 212
 213 /**
 214  * v9fs_file_write - write to a file
 215  * @filep: file pointer to write
 216  * @data: data buffer to write data from
 217  * @count: size of buffer
 218  * @offset: offset at which to write data
 219  *
 220  */
 221
 222 static ssize_t
 223 v9fs_file_write(struct file *filp, const char __user * data,
 224                 size_t count, loff_t * offset)
 225 {
 226         struct inode *inode = filp->f_dentry->d_inode;
 227         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 228         struct v9fs_fid *v9fid = filp->private_data;
 229         struct v9fs_fcall *fcall;
 230         int fid = v9fid->fid;
 231         int result = -EIO;
 232         int rsize = 0;
 233         int total = 0;
 234
 235         dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
 236                 (int)*offset);
 237         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 238         if (v9fid->iounit != 0 && rsize > v9fid->iounit)
 239                 rsize = v9fid->iounit;
 240
 241         do {
 242                 if (count < rsize)
 243                         rsize = count;
 244
 245                 result = v9fs_t_write(v9ses, fid, *offset, rsize, data, &fcall);
 246                 if (result < 0) {
 247                         PRINT_FCALL_ERROR("error while writing", fcall);
 248                         kfree(fcall);
 249                         return result;
 250                 } else
 251                         *offset += result;
 252
 253                 kfree(fcall);
 254                 fcall = NULL;
 255
 256                 if (result != rsize) {
 257                         eprintk(KERN_ERR,
 258                                 "short write: v9fs_t_write returned %d\n",
 259                                 result);
 260                         break;
 261                 }
 262
 263                 count -= result;
 264                 data += result;
 265                 total += result;
 266         } while (count);
 267
 268                 invalidate_inode_pages2(inode->i_mapping);
 269         return total;
 270 }
 271
 272 struct file_operations v9fs_file_operations = {
 273         .llseek = generic_file_llseek,
 274         .read = v9fs_file_read,
 275         .write = v9fs_file_write,
 276         .open = v9fs_file_open,
 277         .release = v9fs_dir_release,
 278         .lock = v9fs_file_lock,
 279         .mmap = generic_file_mmap,
 280 };