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