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
  26 #include "coda_int.h"
  27
  28 static ssize_t
  29 coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos)
  30 {
  31         struct coda_file_info *cfi;
  32         struct file *host_file;
  33
  34         cfi = CODA_FTOC(coda_file);
  35         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  36         host_file = cfi->cfi_container;
  37
  38         if (!host_file->f_op || !host_file->f_op->read)
  39                 return -EINVAL;
  40
  41         return host_file->f_op->read(host_file, buf, count, ppos);
  42 }
  43
  44 static ssize_t
  45 coda_file_splice_read(struct file *coda_file, loff_t *ppos,
  46                       struct pipe_inode_info *pipe, size_t count,
  47                       unsigned int flags)
  48 {
  49         struct coda_file_info *cfi;
  50         struct file *host_file;
  51
  52         cfi = CODA_FTOC(coda_file);
  53         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  54         host_file = cfi->cfi_container;
  55
  56         if (!host_file->f_op || !host_file->f_op->splice_read)
  57                 return -EINVAL;
  58
  59         return host_file->f_op->splice_read(host_file, ppos, pipe, count,flags);
  60 }
  61
  62 static ssize_t
  63 coda_file_write(struct file *coda_file, const char __user *buf, size_t count, loff_t *ppos)
  64 {
  65         struct inode *host_inode, *coda_inode = coda_file->f_path.dentry->d_inode;
  66         struct coda_file_info *cfi;
  67         struct file *host_file;
  68         ssize_t ret;
  69
  70         cfi = CODA_FTOC(coda_file);
  71         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  72         host_file = cfi->cfi_container;
  73
  74         if (!host_file->f_op || !host_file->f_op->write)
  75                 return -EINVAL;
  76
  77         host_inode = host_file->f_path.dentry->d_inode;
  78         mutex_lock(&coda_inode->i_mutex);
  79
  80         ret = host_file->f_op->write(host_file, buf, count, ppos);
  81
  82         coda_inode->i_size = host_inode->i_size;
  83         coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
  84         coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME_SEC;
  85         mutex_unlock(&coda_inode->i_mutex);
  86
  87         return ret;
  88 }
  89
  90 static int
  91 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
  92 {
  93         struct coda_file_info *cfi;
  94         struct coda_inode_info *cii;
  95         struct file *host_file;
  96         struct inode *coda_inode, *host_inode;
  97
  98         cfi = CODA_FTOC(coda_file);
  99         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 100         host_file = cfi->cfi_container;
 101
 102         if (!host_file->f_op || !host_file->f_op->mmap)
 103                 return -ENODEV;
 104
 105         coda_inode = coda_file->f_path.dentry->d_inode;
 106         host_inode = host_file->f_path.dentry->d_inode;
 107         coda_file->f_mapping = host_file->f_mapping;
 108         if (coda_inode->i_mapping == &coda_inode->i_data)
 109                 coda_inode->i_mapping = host_inode->i_mapping;
 110
 111         /* only allow additional mmaps as long as userspace isn't changing
 112          * the container file on us! */
 113         else if (coda_inode->i_mapping != host_inode->i_mapping)
 114                 return -EBUSY;
 115
 116         /* keep track of how often the coda_inode/host_file has been mmapped */
 117         cii = ITOC(coda_inode);
 118         cii->c_mapcount++;
 119         cfi->cfi_mapcount++;
 120
 121         return host_file->f_op->mmap(host_file, vma);
 122 }
 123
 124 int coda_open(struct inode *coda_inode, struct file *coda_file)
 125 {
 126         struct file *host_file = NULL;
 127         int error;
 128         unsigned short flags = coda_file->f_flags & (~O_EXCL);
 129         unsigned short coda_flags = coda_flags_to_cflags(flags);
 130         struct coda_file_info *cfi;
 131
 132         cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
 133         if (!cfi)
 134                 return -ENOMEM;
 135
 136         lock_kernel();
 137
 138         error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
 139                            &host_file);
 140         if (!host_file)
 141                 error = -EIO;
 142
 143         if (error) {
 144                 kfree(cfi);
 145                 unlock_kernel();
 146                 return error;
 147         }
 148
 149         host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
 150
 151         cfi->cfi_magic = CODA_MAGIC;
 152         cfi->cfi_mapcount = 0;
 153         cfi->cfi_container = host_file;
 154
 155         BUG_ON(coda_file->private_data != NULL);
 156         coda_file->private_data = cfi;
 157
 158         unlock_kernel();
 159         return 0;
 160 }
 161
 162 int coda_release(struct inode *coda_inode, struct file *coda_file)
 163 {
 164         unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
 165         unsigned short coda_flags = coda_flags_to_cflags(flags);
 166         struct coda_file_info *cfi;
 167         struct coda_inode_info *cii;
 168         struct inode *host_inode;
 169         int err = 0;
 170
 171         lock_kernel();
 172
 173         cfi = CODA_FTOC(coda_file);
 174         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 175
 176         err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
 177                           coda_flags, coda_file->f_uid);
 178
 179         host_inode = cfi->cfi_container->f_path.dentry->d_inode;
 180         cii = ITOC(coda_inode);
 181
 182         /* did we mmap this file? */
 183         if (coda_inode->i_mapping == &host_inode->i_data) {
 184                 cii->c_mapcount -= cfi->cfi_mapcount;
 185                 if (!cii->c_mapcount)
 186                         coda_inode->i_mapping = &coda_inode->i_data;
 187         }
 188
 189         fput(cfi->cfi_container);
 190         kfree(coda_file->private_data);
 191         coda_file->private_data = NULL;
 192
 193         unlock_kernel();
 194
 195         /* VFS fput ignores the return value from file_operations->release, so
 196          * there is no use returning an error here */
 197         return 0;
 198 }
 199
 200 int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync)
 201 {
 202         struct file *host_file;
 203         struct dentry *host_dentry;
 204         struct inode *host_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         if (host_file->f_op && host_file->f_op->fsync) {
 217                 host_dentry = host_file->f_path.dentry;
 218                 host_inode = host_dentry->d_inode;
 219                 mutex_lock(&host_inode->i_mutex);
 220                 err = host_file->f_op->fsync(host_file, host_dentry, datasync);
 221                 mutex_unlock(&host_inode->i_mutex);
 222         }
 223
 224         if ( !err && !datasync ) {
 225                 lock_kernel();
 226                 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
 227                 unlock_kernel();
 228         }
 229
 230         return err;
 231 }
 232
 233 const struct file_operations coda_file_operations = {
 234         .llseek         = generic_file_llseek,
 235         .read           = coda_file_read,
 236         .write          = coda_file_write,
 237         .mmap           = coda_file_mmap,
 238         .open           = coda_open,
 239         .release        = coda_release,
 240         .fsync          = coda_fsync,
 241         .splice_read    = coda_file_splice_read,
 242 };
 243