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/cred.h>
  17 #include <linux/errno.h>
  18 #include <linux/smp_lock.h>
  19 #include <linux/string.h>
  20 #include <linux/slab.h>
  21 #include <asm/uaccess.h>
  22
  23 #include <linux/coda.h>
  24 #include <linux/coda_linux.h>
  25 #include <linux/coda_fs_i.h>
  26 #include <linux/coda_psdev.h>
  27
  28 #include "coda_int.h"
  29
  30 static ssize_t
  31 coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos)
  32 {
  33         struct coda_file_info *cfi;
  34         struct file *host_file;
  35
  36         cfi = CODA_FTOC(coda_file);
  37         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  38         host_file = cfi->cfi_container;
  39
  40         if (!host_file->f_op || !host_file->f_op->read)
  41                 return -EINVAL;
  42
  43         return host_file->f_op->read(host_file, buf, count, ppos);
  44 }
  45
  46 static ssize_t
  47 coda_file_splice_read(struct file *coda_file, loff_t *ppos,
  48                       struct pipe_inode_info *pipe, size_t count,
  49                       unsigned int flags)
  50 {
  51         ssize_t (*splice_read)(struct file *, loff_t *,
  52                                struct pipe_inode_info *, size_t, unsigned int);
  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         splice_read = host_file->f_op->splice_read;
  61         if (!splice_read)
  62                 splice_read = default_file_splice_read;
  63
  64         return 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         cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
 138         if (!cfi)
 139                 return -ENOMEM;
 140
 141         lock_kernel();
 142
 143         error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
 144                            &host_file);
 145         if (!host_file)
 146                 error = -EIO;
 147
 148         if (error) {
 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_release(struct inode *coda_inode, 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 coda_inode_info *cii;
 173         struct inode *host_inode;
 174         int err = 0;
 175
 176         lock_kernel();
 177
 178         cfi = CODA_FTOC(coda_file);
 179         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 180
 181         err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
 182                           coda_flags, coda_file->f_cred->fsuid);
 183
 184         host_inode = cfi->cfi_container->f_path.dentry->d_inode;
 185         cii = ITOC(coda_inode);
 186
 187         /* did we mmap this file? */
 188         if (coda_inode->i_mapping == &host_inode->i_data) {
 189                 cii->c_mapcount -= cfi->cfi_mapcount;
 190                 if (!cii->c_mapcount)
 191                         coda_inode->i_mapping = &coda_inode->i_data;
 192         }
 193
 194         fput(cfi->cfi_container);
 195         kfree(coda_file->private_data);
 196         coda_file->private_data = NULL;
 197
 198         unlock_kernel();
 199
 200         /* VFS fput ignores the return value from file_operations->release, so
 201          * there is no use returning an error here */
 202         return 0;
 203 }
 204
 205 int coda_fsync(struct file *coda_file, int datasync)
 206 {
 207         struct file *host_file;
 208         struct inode *coda_inode = coda_file->f_path.dentry->d_inode;
 209         struct coda_file_info *cfi;
 210         int err = 0;
 211
 212         if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
 213               S_ISLNK(coda_inode->i_mode)))
 214                 return -EINVAL;
 215
 216         cfi = CODA_FTOC(coda_file);
 217         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 218         host_file = cfi->cfi_container;
 219
 220         err = vfs_fsync(host_file, datasync);
 221         if ( !err && !datasync ) {
 222                 lock_kernel();
 223                 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
 224                 unlock_kernel();
 225         }
 226
 227         return err;
 228 }
 229
 230 const struct file_operations coda_file_operations = {
 231         .llseek         = generic_file_llseek,
 232         .read           = coda_file_read,
 233         .write          = coda_file_write,
 234         .mmap           = coda_file_mmap,
 235         .open           = coda_open,
 236         .release        = coda_release,
 237         .fsync          = coda_fsync,
 238         .splice_read    = coda_file_splice_read,
 239 };
 240