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_sendfile(struct file *coda_file, loff_t *ppos, size_t count,
  51                    read_actor_t actor, void *target)
  52 {
  53         struct coda_file_info *cfi;
  54         struct file *host_file;
  55
  56         cfi = CODA_FTOC(coda_file);
  57         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  58         host_file = cfi->cfi_container;
  59
  60         if (!host_file->f_op || !host_file->f_op->sendfile)
  61                 return -EINVAL;
  62
  63         return host_file->f_op->sendfile(host_file, ppos, count, actor, target);
  64 }
  65
  66 static ssize_t
  67 coda_file_write(struct file *coda_file, const char __user *buf, size_t count, loff_t *ppos)
  68 {
  69         struct inode *host_inode, *coda_inode = coda_file->f_dentry->d_inode;
  70         struct coda_file_info *cfi;
  71         struct file *host_file;
  72         ssize_t ret;
  73
  74         cfi = CODA_FTOC(coda_file);
  75         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  76         host_file = cfi->cfi_container;
  77
  78         if (!host_file->f_op || !host_file->f_op->write)
  79                 return -EINVAL;
  80
  81         host_inode = host_file->f_dentry->d_inode;
  82         mutex_lock(&coda_inode->i_mutex);
  83
  84         ret = host_file->f_op->write(host_file, buf, count, ppos);
  85
  86         coda_inode->i_size = host_inode->i_size;
  87         coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
  88         coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME_SEC;
  89         mutex_unlock(&coda_inode->i_mutex);
  90
  91         return ret;
  92 }
  93
  94 static int
  95 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
  96 {
  97         struct coda_file_info *cfi;
  98         struct coda_inode_info *cii;
  99         struct file *host_file;
 100         struct inode *coda_inode, *host_inode;
 101
 102         cfi = CODA_FTOC(coda_file);
 103         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 104         host_file = cfi->cfi_container;
 105
 106         if (!host_file->f_op || !host_file->f_op->mmap)
 107                 return -ENODEV;
 108
 109         coda_inode = coda_file->f_dentry->d_inode;
 110         host_inode = host_file->f_dentry->d_inode;
 111         coda_file->f_mapping = host_file->f_mapping;
 112         if (coda_inode->i_mapping == &coda_inode->i_data)
 113                 coda_inode->i_mapping = host_inode->i_mapping;
 114
 115         /* only allow additional mmaps as long as userspace isn't changing
 116          * the container file on us! */
 117         else if (coda_inode->i_mapping != host_inode->i_mapping)
 118                 return -EBUSY;
 119
 120         /* keep track of how often the coda_inode/host_file has been mmapped */
 121         cii = ITOC(coda_inode);
 122         cii->c_mapcount++;
 123         cfi->cfi_mapcount++;
 124
 125         return host_file->f_op->mmap(host_file, vma);
 126 }
 127
 128 int coda_open(struct inode *coda_inode, struct file *coda_file)
 129 {
 130         struct file *host_file = NULL;
 131         int error;
 132         unsigned short flags = coda_file->f_flags & (~O_EXCL);
 133         unsigned short coda_flags = coda_flags_to_cflags(flags);
 134         struct coda_file_info *cfi;
 135
 136         coda_vfs_stat.open++;
 137
 138         cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
 139         if (!cfi) {
 140                 unlock_kernel();
 141                 return -ENOMEM;
 142         }
 143
 144         lock_kernel();
 145
 146         error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
 147                            &host_file);
 148         if (error || !host_file) {
 149                 kfree(cfi);
 150                 unlock_kernel();
 151                 return error;
 152         }
 153
 154         host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
 155
 156         cfi->cfi_magic = CODA_MAGIC;
 157         cfi->cfi_mapcount = 0;
 158         cfi->cfi_container = host_file;
 159
 160         BUG_ON(coda_file->private_data != NULL);
 161         coda_file->private_data = cfi;
 162
 163         unlock_kernel();
 164         return 0;
 165 }
 166
 167 int coda_flush(struct file *coda_file)
 168 {
 169         unsigned short flags = coda_file->f_flags & ~O_EXCL;
 170         unsigned short coda_flags = coda_flags_to_cflags(flags);
 171         struct coda_file_info *cfi;
 172         struct inode *coda_inode;
 173         int err = 0, fcnt;
 174
 175         lock_kernel();
 176
 177         coda_vfs_stat.flush++;
 178
 179         /* last close semantics */
 180         fcnt = file_count(coda_file);
 181         if (fcnt > 1)
 182                 goto out;
 183
 184         /* No need to make an upcall when we have not made any modifications
 185          * to the file */
 186         if ((coda_file->f_flags & O_ACCMODE) == O_RDONLY)
 187                 goto out;
 188
 189         if (use_coda_close)
 190                 goto out;
 191
 192         cfi = CODA_FTOC(coda_file);
 193         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 194
 195         coda_inode = coda_file->f_dentry->d_inode;
 196
 197         err = venus_store(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
 198                           coda_file->f_uid);
 199
 200         if (err == -EOPNOTSUPP) {
 201                 use_coda_close = 1;
 202                 err = 0;
 203         }
 204
 205 out:
 206         unlock_kernel();
 207         return err;
 208 }
 209
 210 int coda_release(struct inode *coda_inode, struct file *coda_file)
 211 {
 212         unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
 213         unsigned short coda_flags = coda_flags_to_cflags(flags);
 214         struct coda_file_info *cfi;
 215         struct coda_inode_info *cii;
 216         struct inode *host_inode;
 217         int err = 0;
 218
 219         lock_kernel();
 220         coda_vfs_stat.release++;
 221
 222         if (!use_coda_close) {
 223                 err = venus_release(coda_inode->i_sb, coda_i2f(coda_inode),
 224                                     coda_flags);
 225                 if (err == -EOPNOTSUPP) {
 226                         use_coda_close = 1;
 227                         err = 0;
 228                 }
 229         }
 230
 231         cfi = CODA_FTOC(coda_file);
 232         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 233
 234         if (use_coda_close)
 235                 err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
 236                                   coda_flags, coda_file->f_uid);
 237
 238         host_inode = cfi->cfi_container->f_dentry->d_inode;
 239         cii = ITOC(coda_inode);
 240
 241         /* did we mmap this file? */
 242         if (coda_inode->i_mapping == &host_inode->i_data) {
 243                 cii->c_mapcount -= cfi->cfi_mapcount;
 244                 if (!cii->c_mapcount)
 245                         coda_inode->i_mapping = &coda_inode->i_data;
 246         }
 247
 248         fput(cfi->cfi_container);
 249         kfree(coda_file->private_data);
 250         coda_file->private_data = NULL;
 251
 252         unlock_kernel();
 253         return err;
 254 }
 255
 256 int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync)
 257 {
 258         struct file *host_file;
 259         struct dentry *host_dentry;
 260         struct inode *host_inode, *coda_inode = coda_dentry->d_inode;
 261         struct coda_file_info *cfi;
 262         int err = 0;
 263
 264         if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
 265               S_ISLNK(coda_inode->i_mode)))
 266                 return -EINVAL;
 267
 268         cfi = CODA_FTOC(coda_file);
 269         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 270         host_file = cfi->cfi_container;
 271
 272         coda_vfs_stat.fsync++;
 273
 274         if (host_file->f_op && host_file->f_op->fsync) {
 275                 host_dentry = host_file->f_dentry;
 276                 host_inode = host_dentry->d_inode;
 277                 mutex_lock(&host_inode->i_mutex);
 278                 err = host_file->f_op->fsync(host_file, host_dentry, datasync);
 279                 mutex_unlock(&host_inode->i_mutex);
 280         }
 281
 282         if ( !err && !datasync ) {
 283                 lock_kernel();
 284                 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
 285                 unlock_kernel();
 286         }
 287
 288         return err;
 289 }
 290
 291 const struct file_operations coda_file_operations = {
 292         .llseek         = generic_file_llseek,
 293         .read           = coda_file_read,
 294         .write          = coda_file_write,
 295         .mmap           = coda_file_mmap,
 296         .open           = coda_open,
 297         .flush          = coda_flush,
 298         .release        = coda_release,
 299         .fsync          = coda_fsync,
 300         .sendfile       = coda_file_sendfile,
 301 };
 302