linux/fs/coda/file.c
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   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
  28static ssize_t
  29coda_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
  44static ssize_t
  45coda_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
  62static ssize_t
  63coda_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
  90static int
  91coda_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
 124int 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
 162int 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
 200int 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
 233const 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
 244
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