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 <asm/uaccess.h>
  21
  22 #include <linux/coda.h>
  23 #include <linux/coda_linux.h>
  24 #include <linux/coda_fs_i.h>
  25 #include <linux/coda_psdev.h>
  26
  27 #include "coda_int.h"
  28
  29 static ssize_t
  30 coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos)
  31 {
  32         struct coda_file_info *cfi;
  33         struct file *host_file;
  34
  35         cfi = CODA_FTOC(coda_file);
  36         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  37         host_file = cfi->cfi_container;
  38
  39         if (!host_file->f_op || !host_file->f_op->read)
  40                 return -EINVAL;
  41
  42         return host_file->f_op->read(host_file, buf, count, ppos);
  43 }
  44
  45 static ssize_t
  46 coda_file_splice_read(struct file *coda_file, loff_t *ppos,
  47                       struct pipe_inode_info *pipe, size_t count,
  48                       unsigned int flags)
  49 {
  50         struct coda_file_info *cfi;
  51         struct file *host_file;
  52
  53         cfi = CODA_FTOC(coda_file);
  54         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  55         host_file = cfi->cfi_container;
  56
  57         if (!host_file->f_op || !host_file->f_op->splice_read)
  58                 return -EINVAL;
  59
  60         return host_file->f_op->splice_read(host_file, ppos, pipe, count,flags);
  61 }
  62
  63 static ssize_t
  64 coda_file_write(struct file *coda_file, const char __user *buf, size_t count, loff_t *ppos)
  65 {
  66         struct inode *host_inode, *coda_inode = coda_file->f_path.dentry->d_inode;
  67         struct coda_file_info *cfi;
  68         struct file *host_file;
  69         ssize_t ret;
  70
  71         cfi = CODA_FTOC(coda_file);
  72         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  73         host_file = cfi->cfi_container;
  74
  75         if (!host_file->f_op || !host_file->f_op->write)
  76                 return -EINVAL;
  77
  78         host_inode = host_file->f_path.dentry->d_inode;
  79         mutex_lock(&coda_inode->i_mutex);
  80
  81         ret = host_file->f_op->write(host_file, buf, count, ppos);
  82
  83         coda_inode->i_size = host_inode->i_size;
  84         coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
  85         coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME_SEC;
  86         mutex_unlock(&coda_inode->i_mutex);
  87
  88         return ret;
  89 }
  90
  91 static int
  92 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
  93 {
  94         struct coda_file_info *cfi;
  95         struct coda_inode_info *cii;
  96         struct file *host_file;
  97         struct inode *coda_inode, *host_inode;
  98
  99         cfi = CODA_FTOC(coda_file);
 100         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 101         host_file = cfi->cfi_container;
 102
 103         if (!host_file->f_op || !host_file->f_op->mmap)
 104                 return -ENODEV;
 105
 106         coda_inode = coda_file->f_path.dentry->d_inode;
 107         host_inode = host_file->f_path.dentry->d_inode;
 108         coda_file->f_mapping = host_file->f_mapping;
 109         if (coda_inode->i_mapping == &coda_inode->i_data)
 110                 coda_inode->i_mapping = host_inode->i_mapping;
 111
 112         /* only allow additional mmaps as long as userspace isn't changing
 113          * the container file on us! */
 114         else if (coda_inode->i_mapping != host_inode->i_mapping)
 115                 return -EBUSY;
 116
 117         /* keep track of how often the coda_inode/host_file has been mmapped */
 118         cii = ITOC(coda_inode);
 119         cii->c_mapcount++;
 120         cfi->cfi_mapcount++;
 121
 122         return host_file->f_op->mmap(host_file, vma);
 123 }
 124
 125 int coda_open(struct inode *coda_inode, struct file *coda_file)
 126 {
 127         struct file *host_file = NULL;
 128         int error;
 129         unsigned short flags = coda_file->f_flags & (~O_EXCL);
 130         unsigned short coda_flags = coda_flags_to_cflags(flags);
 131         struct coda_file_info *cfi;
 132
 133         cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
 134         if (!cfi)
 135                 return -ENOMEM;
 136
 137         lock_kernel();
 138
 139         error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
 140                            &host_file);
 141         if (!host_file)
 142                 error = -EIO;
 143
 144         if (error) {
 145                 kfree(cfi);
 146                 unlock_kernel();
 147                 return error;
 148         }
 149
 150         host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
 151
 152         cfi->cfi_magic = CODA_MAGIC;
 153         cfi->cfi_mapcount = 0;
 154         cfi->cfi_container = host_file;
 155
 156         BUG_ON(coda_file->private_data != NULL);
 157         coda_file->private_data = cfi;
 158
 159         unlock_kernel();
 160         return 0;
 161 }
 162
 163 int coda_release(struct inode *coda_inode, struct file *coda_file)
 164 {
 165         unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
 166         unsigned short coda_flags = coda_flags_to_cflags(flags);
 167         struct coda_file_info *cfi;
 168         struct coda_inode_info *cii;
 169         struct inode *host_inode;
 170         int err = 0;
 171
 172         lock_kernel();
 173
 174         cfi = CODA_FTOC(coda_file);
 175         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 176
 177         err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
 178                           coda_flags, coda_file->f_cred->fsuid);
 179
 180         host_inode = cfi->cfi_container->f_path.dentry->d_inode;
 181         cii = ITOC(coda_inode);
 182
 183         /* did we mmap this file? */
 184         if (coda_inode->i_mapping == &host_inode->i_data) {
 185                 cii->c_mapcount -= cfi->cfi_mapcount;
 186                 if (!cii->c_mapcount)
 187                         coda_inode->i_mapping = &coda_inode->i_data;
 188         }
 189
 190         fput(cfi->cfi_container);
 191         kfree(coda_file->private_data);
 192         coda_file->private_data = NULL;
 193
 194         unlock_kernel();
 195
 196         /* VFS fput ignores the return value from file_operations->release, so
 197          * there is no use returning an error here */
 198         return 0;
 199 }
 200
 201 int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync)
 202 {
 203         struct file *host_file;
 204         struct inode *coda_inode = coda_dentry->d_inode;
 205         struct coda_file_info *cfi;
 206         int err = 0;
 207
 208         if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
 209               S_ISLNK(coda_inode->i_mode)))
 210                 return -EINVAL;
 211
 212         cfi = CODA_FTOC(coda_file);
 213         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 214         host_file = cfi->cfi_container;
 215
 216         err = vfs_fsync(host_file, host_file->f_path.dentry, datasync);
 217         if ( !err && !datasync ) {
 218                 lock_kernel();
 219                 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
 220                 unlock_kernel();
 221         }
 222
 223         return err;
 224 }
 225
 226 const struct file_operations coda_file_operations = {
 227         .llseek         = generic_file_llseek,
 228         .read           = coda_file_read,
 229         .write          = coda_file_write,
 230         .mmap           = coda_file_mmap,
 231         .open           = coda_open,
 232         .release        = coda_release,
 233         .fsync          = coda_fsync,
 234         .splice_read    = coda_file_splice_read,
 235 };
 236