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 #include <linux/coda_proc.h>
  26
  27 /* if CODA_STORE fails with EOPNOTSUPP, venus clearly doesn't support
  28  * CODA_STORE/CODA_RELEASE and we fall back on using the CODA_CLOSE upcall */
  29 static int use_coda_close;
  30
  31 static ssize_t
  32 coda_file_read(struct file *coda_file, char __user *buf, size_t count, loff_t *ppos)
  33 {
  34         struct coda_file_info *cfi;
  35         struct file *host_file;
  36
  37         cfi = CODA_FTOC(coda_file);
  38         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  39         host_file = cfi->cfi_container;
  40
  41         if (!host_file->f_op || !host_file->f_op->read)
  42                 return -EINVAL;
  43
  44         return host_file->f_op->read(host_file, buf, count, ppos);
  45 }
  46
  47 static ssize_t
  48 coda_file_sendfile(struct file *coda_file, loff_t *ppos, size_t count,
  49                    read_actor_t actor, void *target)
  50 {
  51         struct coda_file_info *cfi;
  52         struct file *host_file;
  53
  54         cfi = CODA_FTOC(coda_file);
  55         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  56         host_file = cfi->cfi_container;
  57
  58         if (!host_file->f_op || !host_file->f_op->sendfile)
  59                 return -EINVAL;
  60
  61         return host_file->f_op->sendfile(host_file, ppos, count, actor, target);
  62 }
  63
  64 static ssize_t
  65 coda_file_write(struct file *coda_file, const char __user *buf, size_t count, loff_t *ppos)
  66 {
  67         struct inode *host_inode, *coda_inode = coda_file->f_dentry->d_inode;
  68         struct coda_file_info *cfi;
  69         struct file *host_file;
  70         ssize_t ret;
  71
  72         cfi = CODA_FTOC(coda_file);
  73         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
  74         host_file = cfi->cfi_container;
  75
  76         if (!host_file->f_op || !host_file->f_op->write)
  77                 return -EINVAL;
  78
  79         host_inode = host_file->f_dentry->d_inode;
  80         down(&coda_inode->i_sem);
  81
  82         ret = host_file->f_op->write(host_file, buf, count, ppos);
  83
  84         coda_inode->i_size = host_inode->i_size;
  85         coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
  86         coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME_SEC;
  87         up(&coda_inode->i_sem);
  88
  89         return ret;
  90 }
  91
  92 static int
  93 coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
  94 {
  95         struct coda_file_info *cfi;
  96         struct coda_inode_info *cii;
  97         struct file *host_file;
  98         struct inode *coda_inode, *host_inode;
  99
 100         cfi = CODA_FTOC(coda_file);
 101         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 102         host_file = cfi->cfi_container;
 103
 104         if (!host_file->f_op || !host_file->f_op->mmap)
 105                 return -ENODEV;
 106
 107         coda_inode = coda_file->f_dentry->d_inode;
 108         host_inode = host_file->f_dentry->d_inode;
 109         coda_file->f_mapping = host_file->f_mapping;
 110         if (coda_inode->i_mapping == &coda_inode->i_data)
 111                 coda_inode->i_mapping = host_inode->i_mapping;
 112
 113         /* only allow additional mmaps as long as userspace isn't changing
 114          * the container file on us! */
 115         else if (coda_inode->i_mapping != host_inode->i_mapping)
 116                 return -EBUSY;
 117
 118         /* keep track of how often the coda_inode/host_file has been mmapped */
 119         cii = ITOC(coda_inode);
 120         cii->c_mapcount++;
 121         cfi->cfi_mapcount++;
 122
 123         return host_file->f_op->mmap(host_file, vma);
 124 }
 125
 126 int coda_open(struct inode *coda_inode, struct file *coda_file)
 127 {
 128         struct file *host_file = NULL;
 129         int error;
 130         unsigned short flags = coda_file->f_flags & (~O_EXCL);
 131         unsigned short coda_flags = coda_flags_to_cflags(flags);
 132         struct coda_file_info *cfi;
 133
 134         coda_vfs_stat.open++;
 135
 136         cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
 137         if (!cfi) {
 138                 unlock_kernel();
 139                 return -ENOMEM;
 140         }
 141
 142         lock_kernel();
 143
 144         error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
 145                            &host_file);
 146         if (error || !host_file) {
 147                 kfree(cfi);
 148                 unlock_kernel();
 149                 return error;
 150         }
 151
 152         host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
 153
 154         cfi->cfi_magic = CODA_MAGIC;
 155         cfi->cfi_mapcount = 0;
 156         cfi->cfi_container = host_file;
 157
 158         BUG_ON(coda_file->private_data != NULL);
 159         coda_file->private_data = cfi;
 160
 161         unlock_kernel();
 162         return 0;
 163 }
 164
 165 int coda_flush(struct file *coda_file)
 166 {
 167         unsigned short flags = coda_file->f_flags & ~O_EXCL;
 168         unsigned short coda_flags = coda_flags_to_cflags(flags);
 169         struct coda_file_info *cfi;
 170         struct inode *coda_inode;
 171         int err = 0, fcnt;
 172
 173         lock_kernel();
 174
 175         coda_vfs_stat.flush++;
 176
 177         /* last close semantics */
 178         fcnt = file_count(coda_file);
 179         if (fcnt > 1)
 180                 goto out;
 181
 182         /* No need to make an upcall when we have not made any modifications
 183          * to the file */
 184         if ((coda_file->f_flags & O_ACCMODE) == O_RDONLY)
 185                 goto out;
 186
 187         if (use_coda_close)
 188                 goto out;
 189
 190         cfi = CODA_FTOC(coda_file);
 191         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 192
 193         coda_inode = coda_file->f_dentry->d_inode;
 194
 195         err = venus_store(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
 196                           coda_file->f_uid);
 197
 198         if (err == -EOPNOTSUPP) {
 199                 use_coda_close = 1;
 200                 err = 0;
 201         }
 202
 203 out:
 204         unlock_kernel();
 205         return err;
 206 }
 207
 208 int coda_release(struct inode *coda_inode, struct file *coda_file)
 209 {
 210         unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
 211         unsigned short coda_flags = coda_flags_to_cflags(flags);
 212         struct coda_file_info *cfi;
 213         struct coda_inode_info *cii;
 214         struct inode *host_inode;
 215         int err = 0;
 216
 217         lock_kernel();
 218         coda_vfs_stat.release++;
 219
 220         if (!use_coda_close) {
 221                 err = venus_release(coda_inode->i_sb, coda_i2f(coda_inode),
 222                                     coda_flags);
 223                 if (err == -EOPNOTSUPP) {
 224                         use_coda_close = 1;
 225                         err = 0;
 226                 }
 227         }
 228
 229         cfi = CODA_FTOC(coda_file);
 230         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 231
 232         if (use_coda_close)
 233                 err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
 234                                   coda_flags, coda_file->f_uid);
 235
 236         host_inode = cfi->cfi_container->f_dentry->d_inode;
 237         cii = ITOC(coda_inode);
 238
 239         /* did we mmap this file? */
 240         if (coda_inode->i_mapping == &host_inode->i_data) {
 241                 cii->c_mapcount -= cfi->cfi_mapcount;
 242                 if (!cii->c_mapcount)
 243                         coda_inode->i_mapping = &coda_inode->i_data;
 244         }
 245
 246         fput(cfi->cfi_container);
 247         kfree(coda_file->private_data);
 248         coda_file->private_data = NULL;
 249
 250         unlock_kernel();
 251         return err;
 252 }
 253
 254 int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync)
 255 {
 256         struct file *host_file;
 257         struct dentry *host_dentry;
 258         struct inode *host_inode, *coda_inode = coda_dentry->d_inode;
 259         struct coda_file_info *cfi;
 260         int err = 0;
 261
 262         if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) ||
 263               S_ISLNK(coda_inode->i_mode)))
 264                 return -EINVAL;
 265
 266         cfi = CODA_FTOC(coda_file);
 267         BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 268         host_file = cfi->cfi_container;
 269
 270         coda_vfs_stat.fsync++;
 271
 272         if (host_file->f_op && host_file->f_op->fsync) {
 273                 host_dentry = host_file->f_dentry;
 274                 host_inode = host_dentry->d_inode;
 275                 down(&host_inode->i_sem);
 276                 err = host_file->f_op->fsync(host_file, host_dentry, datasync);
 277                 up(&host_inode->i_sem);
 278         }
 279
 280         if ( !err && !datasync ) {
 281                 lock_kernel();
 282                 err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));
 283                 unlock_kernel();
 284         }
 285
 286         return err;
 287 }
 288
 289 struct file_operations coda_file_operations = {
 290         .llseek         = generic_file_llseek,
 291         .read           = coda_file_read,
 292         .write          = coda_file_write,
 293         .mmap           = coda_file_mmap,
 294         .open           = coda_open,
 295         .flush          = coda_flush,
 296         .release        = coda_release,
 297         .fsync          = coda_fsync,
 298         .sendfile       = coda_file_sendfile,
 299 };
 300