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, &fcall);
  76         if (err < 0) {
  77                 dprintk(DEBUG_ERROR, "rewalk didn't work\n");
  78                 if (fcall && fcall->id == RWALK)
  79                         goto clunk_fid;
  80                 else {
  81                         v9fs_put_idpool(fid, &v9ses->fidpool);
  82                         goto free_fcall;
  83                 }
  84         }
  85         kfree(fcall);
  86
  87         /* TODO: do special things for O_EXCL, O_NOFOLLOW, O_SYNC */
  88         /* translate open mode appropriately */
  89         omode = v9fs_uflags2omode(file->f_flags);
  90         err = v9fs_t_open(v9ses, fid, omode, &fcall);
  91         if (err < 0) {
  92                 PRINT_FCALL_ERROR("open failed", fcall);
  93                 goto clunk_fid;
  94         }
  95
  96         vfid = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
  97         if (vfid == NULL) {
  98                 dprintk(DEBUG_ERROR, "out of memory\n");
  99                 err = -ENOMEM;
 100                 goto clunk_fid;
 101         }
 102
 103         file->private_data = vfid;
 104         vfid->fid = fid;
 105         vfid->fidopen = 1;
 106         vfid->fidclunked = 0;
 107         vfid->iounit = fcall->params.ropen.iounit;
 108         vfid->rdir_pos = 0;
 109         vfid->rdir_fcall = NULL;
 110         vfid->filp = file;
 111         kfree(fcall);
 112
 113         return 0;
 114
 115 clunk_fid:
 116         v9fs_t_clunk(v9ses, fid);
 117
 118 free_fcall:
 119         kfree(fcall);
 120
 121         return err;
 122 }
 123
 124 /**
 125  * v9fs_file_lock - lock a file (or directory)
 126  * @inode: inode to be opened
 127  * @file: file being opened
 128  *
 129  * XXX - this looks like a local only lock, we should extend into 9P
 130  *       by using open exclusive
 131  */
 132
 133 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 134 {
 135         int res = 0;
 136         struct inode *inode = filp->f_dentry->d_inode;
 137
 138         dprintk(DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
 139
 140         /* No mandatory locks */
 141         if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
 142                 return -ENOLCK;
 143
 144         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
 145                 filemap_write_and_wait(inode->i_mapping);
 146                 invalidate_inode_pages(&inode->i_data);
 147         }
 148
 149         return res;
 150 }
 151
 152 /**
 153  * v9fs_file_read - read from a file
 154  * @filep: file pointer to read
 155  * @data: data buffer to read data into
 156  * @count: size of buffer
 157  * @offset: offset at which to read data
 158  *
 159  */
 160 static ssize_t
 161 v9fs_file_read(struct file *filp, char __user * data, size_t count,
 162                loff_t * offset)
 163 {
 164         struct inode *inode = filp->f_dentry->d_inode;
 165         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 166         struct v9fs_fid *v9f = filp->private_data;
 167         struct v9fs_fcall *fcall = NULL;
 168         int fid = v9f->fid;
 169         int rsize = 0;
 170         int result = 0;
 171         int total = 0;
 172         int n;
 173
 174         dprintk(DEBUG_VFS, "\n");
 175
 176         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 177         if (v9f->iounit != 0 && rsize > v9f->iounit)
 178                 rsize = v9f->iounit;
 179
 180         do {
 181                 if (count < rsize)
 182                         rsize = count;
 183
 184                 result = v9fs_t_read(v9ses, fid, *offset, rsize, &fcall);
 185
 186                 if (result < 0) {
 187                         printk(KERN_ERR "9P2000: v9fs_t_read returned %d\n",
 188                                result);
 189
 190                         kfree(fcall);
 191                         return total;
 192                 } else
 193                         *offset += result;
 194
 195                 n = copy_to_user(data, fcall->params.rread.data, result);
 196                 if (n) {
 197                         dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
 198                         kfree(fcall);
 199                         return -EFAULT;
 200                 }
 201
 202                 count -= result;
 203                 data += result;
 204                 total += result;
 205
 206                 kfree(fcall);
 207
 208                 if (result < rsize)
 209                         break;
 210         } while (count);
 211
 212         return total;
 213 }
 214
 215 /**
 216  * v9fs_file_write - write to a file
 217  * @filep: file pointer to write
 218  * @data: data buffer to write data from
 219  * @count: size of buffer
 220  * @offset: offset at which to write data
 221  *
 222  */
 223
 224 static ssize_t
 225 v9fs_file_write(struct file *filp, const char __user * data,
 226                 size_t count, loff_t * offset)
 227 {
 228         struct inode *inode = filp->f_dentry->d_inode;
 229         struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
 230         struct v9fs_fid *v9fid = filp->private_data;
 231         struct v9fs_fcall *fcall;
 232         int fid = v9fid->fid;
 233         int result = -EIO;
 234         int rsize = 0;
 235         int total = 0;
 236
 237         dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
 238                 (int)*offset);
 239         rsize = v9ses->maxdata - V9FS_IOHDRSZ;
 240         if (v9fid->iounit != 0 && rsize > v9fid->iounit)
 241                 rsize = v9fid->iounit;
 242
 243         do {
 244                 if (count < rsize)
 245                         rsize = count;
 246
 247                 result = v9fs_t_write(v9ses, fid, *offset, rsize, data, &fcall);
 248                 if (result < 0) {
 249                         PRINT_FCALL_ERROR("error while writing", fcall);
 250                         kfree(fcall);
 251                         return result;
 252                 } else
 253                         *offset += result;
 254
 255                 kfree(fcall);
 256                 fcall = NULL;
 257
 258                 if (result != rsize) {
 259                         eprintk(KERN_ERR,
 260                                 "short write: v9fs_t_write returned %d\n",
 261                                 result);
 262                         break;
 263                 }
 264
 265                 count -= result;
 266                 data += result;
 267                 total += result;
 268         } while (count);
 269
 270                 invalidate_inode_pages2(inode->i_mapping);
 271         return total;
 272 }
 273
 274 const struct file_operations v9fs_file_operations = {
 275         .llseek = generic_file_llseek,
 276         .read = v9fs_file_read,
 277         .write = v9fs_file_write,
 278         .open = v9fs_file_open,
 279         .release = v9fs_dir_release,
 280         .lock = v9fs_file_lock,
 281         .mmap = generic_file_mmap,
 282 };