release/src-rt-6.x/linux/linux-2.6/fs/coda/file.c

   1 /*
   2  * File operations for Coda.
   3  * Original version: (C) 1996 Peter Braam
   4  * Rewritten for Linux 2.1: (C) 1997 Carnegie Mellon University
   5  *
   6  * Carnegie Mellon encourages users of this code to contribute improvements
   7  * to the Coda project. Contact Peter Braam <coda@cs.cmu.edu>.
   8  */
   9
  10 #include <linux/types.h>
  11 #include <linux/kernel.h>
  12 #include <linux/time.h>
  13 #include <linux/file.h>
  14 #include <linux/fs.h>
  15 #include <linux/stat.h>
  16 #include <linux/errno.h>
  17 #include <linux/smp_lock.h>
  18 #include <linux/string.h>
  19 #include <asm/uaccess.h>
  20
  21 #include <linux/coda.h>
  22 #include <linux/coda_linux.h>
  23 #include <linux/coda_fs_i.h>
  24 #include <linux/coda_psdev.h>
  25 #include <linux/coda_proc.h>
  26
  27 #include "coda_int.h"
  28
  29 /* if CODA_STORE fails with EOPNOTSUPP, venus clearly doesn't support
  30  * CODA_STORE/CODA_RELEASE and we fall back on using the CODA_CLOSE upcall */
  31 static int use_coda_close;
  32
  33 static ssize_t
  34 coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos)
  35 {
  36         struct coda_file_info *cfi;
  37         struct file *host_file;
  38
  39         cfi = CODA_FTOC(coda_file);
  40         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  41         host_file = cfi->cfi_container;
  42
  43         if (!host_file->f_op || !host_file->f_op->read)
  44                 return -EINVAL;
  45
  46         return host_file->f_op->read(host_file, buf, count, ppos);
  47 }
  48
  49 static ssize_t
  50 coda_file_splice_read(struct file *coda_file, loff_t *ppos,
  51                       struct pipe_inode_info *pipe, size_t count,
  52                       unsigned int flags)
  53 {
  54         struct coda_file_info *cfi;
  55         struct file *host_file;
  56
  57         cfi = CODA_FTOC(coda_file);
  58         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  59         host_file = cfi->cfi_container;
  60
  61         if (!host_file->f_op || !host_file->f_op->splice_read)
  62                 return -EINVAL;
  63
  64         return host_file->f_op->splice_read(host_file, ppos, pipe, count,flags);
  65 }
  66
  67 static ssize_t
  68 coda_file_write(struct file *coda_file, const char __user *buf, size_t count, loff_t *ppos)
  69 {
  70         struct inode *host_inode, *coda_inode = coda_file->f_path.dentry->d_inode;
  71         struct coda_file_info *cfi;
  72         struct file *host_file;
  73         ssize_t ret;
  74
  75         cfi = CODA_FTOC(coda_file);
  76         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  77         host_file = cfi->cfi_container;
  78
  79         if (!host_file->f_op || !host_file->f_op->write)
  80                 return -EINVAL;
  81
  82         host_inode = host_file->f_path.dentry->d_inode;
  83         mutex_lock(&coda_inode->i_mutex);
  84
  85         ret = host_file->f_op->write(host_file, buf, count, ppos);
  86
  87         coda_inode->i_size = host_inode->i_size;
  88         coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
  89         coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME_SEC;
  90         mutex_unlock(&coda_inode->i_mutex);
  91
  92         return ret;
  93 }
  94
  95 static int
  96 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
  97 {
  98         struct coda_file_info *cfi;
  99         struct coda_inode_info *cii;
 100         struct file *host_file;
 101         struct inode *coda_inode, *host_inode;
 102
 103         cfi = CODA_FTOC(coda_file);
 104         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 105         host_file = cfi->cfi_container;
 106
 107         if (!host_file->f_op || !host_file->f_op->mmap)
 108                 return -ENODEV;
 109
 110         coda_inode = coda_file->f_path.dentry->d_inode;
 111         host_inode = host_file->f_path.dentry->d_inode;
 112         coda_file->f_mapping = host_file->f_mapping;
 113         if (coda_inode->i_mapping == &coda_inode->i_data)
 114                 coda_inode->i_mapping = host_inode->i_mapping;
 115
 116         /* only allow additional mmaps as long as userspace isn't changing
 117          * the container file on us! */
 118         else if (coda_inode->i_mapping != host_inode->i_mapping)
 119                 return -EBUSY;
 120
 121         /* keep track of how often the coda_inode/host_file has been mmapped */
 122         cii = ITOC(coda_inode);
 123         cii->c_mapcount++;
 124         cfi->cfi_mapcount++;
 125
 126         return host_file->f_op->mmap(host_file, vma);
 127 }
 128
 129 int coda_open(struct inode *coda_inode, struct file *coda_file)
 130 {
 131         struct file *host_file = NULL;
 132         int error;
 133         unsigned short flags = coda_file->f_flags & (~O_EXCL);
 134         unsigned short coda_flags = coda_flags_to_cflags(flags);
 135         struct coda_file_info *cfi;
 136
 137         coda_vfs_stat.open++;
 138
 139         cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
 140         if (!cfi)
 141                 return -ENOMEM;
 142
 143         lock_kernel();
 144
 145         error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
 146                            &host_file);
 147         if (error || !host_file) {
 148                 kfree(cfi);
 149                 unlock_kernel();
 150                 return error;
 151         }
 152
 153         host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
 154
 155         cfi->cfi_magic = CODA_MAGIC;
 156         cfi->cfi_mapcount = 0;
 157         cfi->cfi_container = host_file;
 158
 159         BUG_ON(coda_file->private_data != NULL);
 160         coda_file->private_data = cfi;
 161
 162         unlock_kernel();
 163         return 0;
 164 }
 165
 166 int coda_flush(struct file *coda_file, fl_owner_t id)
 167 {
 168         unsigned short flags = coda_file->f_flags & ~O_EXCL;
 169         unsigned short coda_flags = coda_flags_to_cflags(flags);
 170         struct coda_file_info *cfi;
 171         struct inode *coda_inode;
 172         int err = 0, fcnt;
 173
 174         lock_kernel();
 175
 176         coda_vfs_stat.flush++;
 177
 178         /* last close semantics */
 179         fcnt = file_count(coda_file);
 180         if (fcnt > 1)
 181                 goto out;
 182
 183         /* No need to make an upcall when we have not made any modifications
 184          * to the file */
 185         if ((coda_file->f_flags & O_ACCMODE) == O_RDONLY)
 186                 goto out;
 187
 188         if (use_coda_close)
 189                 goto out;
 190
 191         cfi = CODA_FTOC(coda_file);
 192         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 193
 194         coda_inode = coda_file->f_path.dentry->d_inode;
 195
 196         err = venus_store(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
 197                           coda_file->f_uid);
 198
 199         if (err == -EOPNOTSUPP) {
 200                 use_coda_close = 1;
 201                 err = 0;
 202         }
 203
 204 out:
 205         unlock_kernel();
 206         return err;
 207 }
 208
 209 int coda_release(struct inode *coda_inode, struct file *coda_file)
 210 {
 211         unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
 212         unsigned short coda_flags = coda_flags_to_cflags(flags);
 213         struct coda_file_info *cfi;
 214         struct coda_inode_info *cii;
 215         struct inode *host_inode;
 216         int err = 0;
 217
 218         lock_kernel();
 219         coda_vfs_stat.release++;
 220
 221         if (!use_coda_close) {
 222                 err = venus_release(coda_inode->i_sb, coda_i2f(coda_inode),
 223                                     coda_flags);
 224                 if (err == -EOPNOTSUPP) {
 225                         use_coda_close = 1;
 226                         err = 0;
 227                 }
 228         }
 229
 230         cfi = CODA_FTOC(coda_file);
 231         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 232
 233         if (use_coda_close)
 234                 err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
 235                                   coda_flags, coda_file->f_uid);
 236
 237         host_inode = cfi->cfi_container->f_path.dentry->d_inode;
 238         cii = ITOC(coda_inode);
 239
 240         /* did we mmap this file? */
 241         if (coda_inode->i_mapping == &host_inode->i_data) {
 242                 cii->c_mapcount -= cfi->cfi_mapcount;
 243                 if (!cii->c_mapcount)
 244                         coda_inode->i_mapping = &coda_inode->i_data;
 245         }
 246
 247         fput(cfi->cfi_container);
 248         kfree(coda_file->private_data);
 249         coda_file->private_data = NULL;
 250
 251         unlock_kernel();
 252         return err;
 253 }
 254
 255 int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync)
 256 {
 257         struct file *host_file;
 258         struct dentry *host_dentry;
 259         struct inode *host_inode, *coda_inode = coda_dentry->d_inode;
 260         struct coda_file_info *cfi;
 261         int err = 0;
 262
 263         if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
 264               S_ISLNK(coda_inode->i_mode)))
 265                 return -EINVAL;
 266
 267         cfi = CODA_FTOC(coda_file);
 268         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 269         host_file = cfi->cfi_container;
 270
 271         coda_vfs_stat.fsync++;
 272
 273         if (host_file->f_op && host_file->f_op->fsync) {
 274                 host_dentry = host_file->f_path.dentry;
 275                 host_inode = host_dentry->d_inode;
 276                 mutex_lock(&host_inode->i_mutex);
 277                 err = host_file->f_op->fsync(host_file, host_dentry, datasync);
 278                 mutex_unlock(&host_inode->i_mutex);
 279         }
 280
 281         if ( !err && !datasync ) {
 282                 lock_kernel();
 283                 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
 284                 unlock_kernel();
 285         }
 286
 287         return err;
 288 }
 289
 290 const struct file_operations coda_file_operations = {
 291         .llseek         = generic_file_llseek,
 292         .read           = coda_file_read,
 293         .write          = coda_file_write,
 294         .mmap           = coda_file_mmap,
 295         .open           = coda_open,
 296         .flush          = coda_flush,
 297         .release        = coda_release,
 298         .fsync          = coda_fsync,
 299         .splice_read    = coda_file_splice_read,
 300 };
 301