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/cred.h>
  17#include <linux/errno.h>
  18#include <linux/spinlock.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_psdev.h>
  25
  26#include "coda_linux.h"
  27#include "coda_int.h"
  28
  29static ssize_t
  30coda_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
  45static ssize_t
  46coda_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        ssize_t (*splice_read)(struct file *, loff_t *,
  51                               struct pipe_inode_info *, size_t, unsigned int);
  52        struct coda_file_info *cfi;
  53        struct file *host_file;
  54
  55        cfi = CODA_FTOC(coda_file);
  56        BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  57        host_file = cfi->cfi_container;
  58
  59        splice_read = host_file->f_op->splice_read;
  60        if (!splice_read)
  61                splice_read = default_file_splice_read;
  62
  63        return splice_read(host_file, ppos, pipe, count, flags);
  64}
  65
  66static ssize_t
  67coda_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_path.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_path.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
  94static int
  95coda_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_path.dentry->d_inode;
 110        host_inode = host_file->f_path.dentry->d_inode;
 111
 112        cii = ITOC(coda_inode);
 113        spin_lock(&cii->c_lock);
 114        coda_file->f_mapping = host_file->f_mapping;
 115        if (coda_inode->i_mapping == &coda_inode->i_data)
 116                coda_inode->i_mapping = host_inode->i_mapping;
 117
 118        /* only allow additional mmaps as long as userspace isn't changing
 119         * the container file on us! */
 120        else if (coda_inode->i_mapping != host_inode->i_mapping) {
 121                spin_unlock(&cii->c_lock);
 122                return -EBUSY;
 123        }
 124
 125        /* keep track of how often the coda_inode/host_file has been mmapped */
 126        cii->c_mapcount++;
 127        cfi->cfi_mapcount++;
 128        spin_unlock(&cii->c_lock);
 129
 130        return host_file->f_op->mmap(host_file, vma);
 131}
 132
 133int coda_open(struct inode *coda_inode, struct file *coda_file)
 134{
 135        struct file *host_file = NULL;
 136        int error;
 137        unsigned short flags = coda_file->f_flags & (~O_EXCL);
 138        unsigned short coda_flags = coda_flags_to_cflags(flags);
 139        struct coda_file_info *cfi;
 140
 141        cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
 142        if (!cfi)
 143                return -ENOMEM;
 144
 145        error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
 146                           &host_file);
 147        if (!host_file)
 148                error = -EIO;
 149
 150        if (error) {
 151                kfree(cfi);
 152                return error;
 153        }
 154
 155        host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
 156
 157        cfi->cfi_magic = CODA_MAGIC;
 158        cfi->cfi_mapcount = 0;
 159        cfi->cfi_container = host_file;
 160
 161        BUG_ON(coda_file->private_data != NULL);
 162        coda_file->private_data = cfi;
 163        return 0;
 164}
 165
 166int coda_release(struct inode *coda_inode, struct file *coda_file)
 167{
 168        unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
 169        unsigned short coda_flags = coda_flags_to_cflags(flags);
 170        struct coda_file_info *cfi;
 171        struct coda_inode_info *cii;
 172        struct inode *host_inode;
 173        int err;
 174
 175        cfi = CODA_FTOC(coda_file);
 176        BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 177
 178        err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
 179                          coda_flags, coda_file->f_cred->fsuid);
 180
 181        host_inode = cfi->cfi_container->f_path.dentry->d_inode;
 182        cii = ITOC(coda_inode);
 183
 184        /* did we mmap this file? */
 185        spin_lock(&cii->c_lock);
 186        if (coda_inode->i_mapping == &host_inode->i_data) {
 187                cii->c_mapcount -= cfi->cfi_mapcount;
 188                if (!cii->c_mapcount)
 189                        coda_inode->i_mapping = &coda_inode->i_data;
 190        }
 191        spin_unlock(&cii->c_lock);
 192
 193        fput(cfi->cfi_container);
 194        kfree(coda_file->private_data);
 195        coda_file->private_data = NULL;
 196
 197        /* VFS fput ignores the return value from file_operations->release, so
 198         * there is no use returning an error here */
 199        return 0;
 200}
 201
 202int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync)
 203{
 204        struct file *host_file;
 205        struct inode *coda_inode = coda_file->f_path.dentry->d_inode;
 206        struct coda_file_info *cfi;
 207        int err;
 208
 209        if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
 210              S_ISLNK(coda_inode->i_mode)))
 211                return -EINVAL;
 212
 213        err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end);
 214        if (err)
 215                return err;
 216        mutex_lock(&coda_inode->i_mutex);
 217
 218        cfi = CODA_FTOC(coda_file);
 219        BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 220        host_file = cfi->cfi_container;
 221
 222        err = vfs_fsync(host_file, datasync);
 223        if (!err && !datasync)
 224                err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
 225        mutex_unlock(&coda_inode->i_mutex);
 226
 227        return err;
 228}
 229
 230const 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
 241
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