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/sched.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 *vfid;
  56         struct v9fs_fcall *fcall = NULL;
  57         int omode;
  58         int err;
  59
  60         dprintk(DEBUG_VFS, "inode: %p file: %p \n", inode, file);
  61
  62         vfid = v9fs_fid_clone(file->f_path.dentry);
  63         if (IS_ERR(vfid))
  64                 return PTR_ERR(vfid);
  65
  66         omode = v9fs_uflags2omode(file->f_flags);
  67         err = v9fs_t_open(v9ses, vfid->fid, omode, &fcall);
  68         if (err < 0) {
  69                 PRINT_FCALL_ERROR("open failed", fcall);
  70                 goto Clunk_Fid;
  71         }
  72
  73         file->private_data = vfid;
  74         vfid->fidopen = 1;
  75         vfid->fidclunked = 0;
  76         vfid->iounit = fcall->params.ropen.iounit;
  77         vfid->rdir_pos = 0;
  78         vfid->rdir_fcall = NULL;
  79         vfid->filp = file;
  80         kfree(fcall);
  81
  82         return 0;
  83
  84 Clunk_Fid:
  85         v9fs_fid_clunk(v9ses, vfid);
  86         kfree(fcall);
  87
  88         return err;
  89 }
  90
  91 /**
  92  * v9fs_file_lock - lock a file (or directory)
  93  * @inode: inode to be opened
  94  * @file: file being opened
  95  *
  96  * XXX - this looks like a local only lock, we should extend into 9P
  97  *       by using open exclusive
  98  */
  99
 100 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 101 {
 102         int res = 0;
 103         struct inode *inode = filp->f_path.dentry->d_inode;
 104
 105         dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 106
 107         /* No mandatory locks */
 108         if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
 109                 return -ENOLCK;
 110
 111         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 112                 filemap_write_and_wait(inode->i_mapping);
 113                 invalidate_inode_pages(&inode->i_data);
 114         }
 115
 116         return res;
 117 }
 118
 119 /**
 120  * v9fs_file_read - read from a file
 121  * @filep: file pointer to read
 122  * @data: data buffer to read data into
 123  * @count: size of buffer
 124  * @offset: offset at which to read data
 125  *
 126  */
 127 static ssize_t
 128 v9fs_file_read(struct file *filp, char __user * data, size_t count,
 129                loff_t * offset)
 130 {
 131         struct inode *inode = filp->f_path.dentry->d_inode;
 132         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 133         struct v9fs_fid *v9f = filp->private_data;
 134         struct v9fs_fcall *fcall = NULL;
 135         int fid = v9f->fid;
 136         int rsize = 0;
 137         int result = 0;
 138         int total = 0;
 139         int n;
 140
 141         dprintk(DEBUG_VFS, "\n");
 142
 143         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 144         if (v9f->iounit != 0 && rsize > v9f->iounit)
 145                 rsize = v9f->iounit;
 146
 147         do {
 148                 if (count < rsize)
 149                         rsize = count;
 150
 151                 result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
 152
 153                 if (result < 0) {
 154                         printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
 155                                result);
 156
 157                         kfree(fcall);
 158                         return total;
 159                 } else
 160                         *offset += result;
 161
 162                 n = copy_to_user(data, fcall->params.rread.data, result);
 163                 if (n) {
 164                         dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
 165                         kfree(fcall);
 166                         return -EFAULT;
 167                 }
 168
 169                 count -= result;
 170                 data += result;
 171                 total += result;
 172
 173                 kfree(fcall);
 174
 175                 if (result < rsize)
 176                         break;
 177         } while (count);
 178
 179         return total;
 180 }
 181
 182 /**
 183  * v9fs_file_write - write to a file
 184  * @filep: file pointer to write
 185  * @data: data buffer to write data from
 186  * @count: size of buffer
 187  * @offset: offset at which to write data
 188  *
 189  */
 190
 191 static ssize_t
 192 v9fs_file_write(struct file *filp, const char __user * data,
 193                 size_t count, loff_t * offset)
 194 {
 195         struct inode *inode = filp->f_path.dentry->d_inode;
 196         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 197         struct v9fs_fid *v9fid = filp->private_data;
 198         struct v9fs_fcall *fcall;
 199         int fid = v9fid->fid;
 200         int result = -EIO;
 201         int rsize = 0;
 202         int total = 0;
 203
 204         dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
 205                 (int)*offset);
 206         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 207         if (v9fid->iounit != 0 && rsize > v9fid->iounit)
 208                 rsize = v9fid->iounit;
 209
 210         do {
 211                 if (count < rsize)
 212                         rsize = count;
 213
 214                 result = v9fs_t_write(v9ses, fid, *offset, rsize, data, &fcall);
 215                 if (result < 0) {
 216                         PRINT_FCALL_ERROR("error while writing", fcall);
 217                         kfree(fcall);
 218                         return result;
 219                 } else
 220                         *offset += result;
 221
 222                 kfree(fcall);
 223                 fcall = NULL;
 224
 225                 if (result != rsize) {
 226                         eprintk(KERN_ERR,
 227                                 "short write: v9fs_t_write returned %d\n",
 228                                 result);
 229                         break;
 230                 }
 231
 232                 count -= result;
 233                 data += result;
 234                 total += result;
 235         } while (count);
 236
 237                 invalidate_inode_pages2(inode->i_mapping);
 238         return total;
 239 }
 240
 241 const struct file_operations v9fs_file_operations = {
 242         .llseek = generic_file_llseek,
 243         .read = v9fs_file_read,
 244         .write = v9fs_file_write,
 245         .open = v9fs_file_open,
 246         .release = v9fs_dir_release,
 247         .lock = v9fs_file_lock,
 248         .mmap = generic_file_mmap,
 249 };