arch/s390/hypfs/inode.c

   1 /*
   2  *  arch/s390/hypfs/inode.c
   3  *    Hypervisor filesystem for Linux on s390.
   4  *
   5  *    Copyright (C) IBM Corp. 2006
   6  *    Author(s): Michael Holzheu <holzheu@de.ibm.com>
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/errno.h>
  11 #include <linux/fs.h>
  12 #include <linux/namei.h>
  13 #include <linux/vfs.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/gfp.h>
  16 #include <linux/time.h>
  17 #include <linux/parser.h>
  18 #include <linux/sysfs.h>
  19 #include <linux/module.h>
  20 #include <linux/seq_file.h>
  21 #include <linux/mount.h>
  22 #include <asm/ebcdic.h>
  23 #include "hypfs.h"
  24
  25 #define HYPFS_MAGIC 0x687970    /* ASCII 'hyp' */
  26 #define TMP_SIZE 64             /* size of temporary buffers */
  27
  28 static struct dentry *hypfs_create_update_file(struct super_block *sb,
  29                                                struct dentry *dir);
  30
  31 struct hypfs_sb_info {
  32         uid_t uid;                      /* uid used for files and dirs */
  33         gid_t gid;                      /* gid used for files and dirs */
  34         struct dentry *update_file;     /* file to trigger update */
  35         time_t last_update;             /* last update time in secs since 1970 */
  36         struct mutex lock;              /* lock to protect update process */
  37 };
  38
  39 static const struct file_operations hypfs_file_ops;
  40 static struct file_system_type hypfs_type;
  41 static struct super_operations hypfs_s_ops;
  42
  43 /* start of list of all dentries, which have to be deleted on update */
  44 static struct dentry *hypfs_last_dentry;
  45
  46 static void hypfs_update_update(struct super_block *sb)
  47 {
  48         struct hypfs_sb_info *sb_info = sb->s_fs_info;
  49         struct inode *inode = sb_info->update_file->d_inode;
  50
  51         sb_info->last_update = get_seconds();
  52         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
  53 }
  54
  55 /* directory tree removal functions */
  56
  57 static void hypfs_add_dentry(struct dentry *dentry)
  58 {
  59         dentry->d_fsdata = hypfs_last_dentry;
  60         hypfs_last_dentry = dentry;
  61 }
  62
  63 static void hypfs_remove(struct dentry *dentry)
  64 {
  65         struct dentry *parent;
  66
  67         parent = dentry->d_parent;
  68         if (S_ISDIR(dentry->d_inode->i_mode))
  69                 simple_rmdir(parent->d_inode, dentry);
  70         else
  71                 simple_unlink(parent->d_inode, dentry);
  72         d_delete(dentry);
  73         dput(dentry);
  74 }
  75
  76 static void hypfs_delete_tree(struct dentry *root)
  77 {
  78         while (hypfs_last_dentry) {
  79                 struct dentry *next_dentry;
  80                 next_dentry = hypfs_last_dentry->d_fsdata;
  81                 hypfs_remove(hypfs_last_dentry);
  82                 hypfs_last_dentry = next_dentry;
  83         }
  84 }
  85
  86 static struct inode *hypfs_make_inode(struct super_block *sb, int mode)
  87 {
  88         struct inode *ret = new_inode(sb);
  89
  90         if (ret) {
  91                 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
  92                 ret->i_mode = mode;
  93                 ret->i_uid = hypfs_info->uid;
  94                 ret->i_gid = hypfs_info->gid;
  95                 ret->i_blocks = 0;
  96                 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
  97                 if (mode & S_IFDIR)
  98                         ret->i_nlink = 2;
  99                 else
 100                         ret->i_nlink = 1;
 101         }
 102         return ret;
 103 }
 104
 105 static void hypfs_drop_inode(struct inode *inode)
 106 {
 107         kfree(inode->i_private);
 108         generic_delete_inode(inode);
 109 }
 110
 111 static int hypfs_open(struct inode *inode, struct file *filp)
 112 {
 113         char *data = filp->f_path.dentry->d_inode->i_private;
 114         struct hypfs_sb_info *fs_info;
 115
 116         if (filp->f_mode & FMODE_WRITE) {
 117                 if (!(inode->i_mode & S_IWUGO))
 118                         return -EACCES;
 119         }
 120         if (filp->f_mode & FMODE_READ) {
 121                 if (!(inode->i_mode & S_IRUGO))
 122                         return -EACCES;
 123         }
 124
 125         fs_info = inode->i_sb->s_fs_info;
 126         if(data) {
 127                 mutex_lock(&fs_info->lock);
 128                 filp->private_data = kstrdup(data, GFP_KERNEL);
 129                 if (!filp->private_data) {
 130                         mutex_unlock(&fs_info->lock);
 131                         return -ENOMEM;
 132                 }
 133                 mutex_unlock(&fs_info->lock);
 134         }
 135         return 0;
 136 }
 137
 138 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
 139                               unsigned long nr_segs, loff_t offset)
 140 {
 141         char *data;
 142         size_t len;
 143         struct file *filp = iocb->ki_filp;
 144         /* XXX: temporary */
 145         char __user *buf = iov[0].iov_base;
 146         size_t count = iov[0].iov_len;
 147
 148         if (nr_segs != 1) {
 149                 count = -EINVAL;
 150                 goto out;
 151         }
 152
 153         data = filp->private_data;
 154         len = strlen(data);
 155         if (offset > len) {
 156                 count = 0;
 157                 goto out;
 158         }
 159         if (count > len - offset)
 160                 count = len - offset;
 161         if (copy_to_user(buf, data + offset, count)) {
 162                 count = -EFAULT;
 163                 goto out;
 164         }
 165         iocb->ki_pos += count;
 166         file_accessed(filp);
 167 out:
 168         return count;
 169 }
 170 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
 171                               unsigned long nr_segs, loff_t offset)
 172 {
 173         int rc;
 174         struct super_block *sb;
 175         struct hypfs_sb_info *fs_info;
 176         size_t count = iov_length(iov, nr_segs);
 177
 178         sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb;
 179         fs_info = sb->s_fs_info;
 180         /*
 181          * Currently we only allow one update per second for two reasons:
 182          * 1. diag 204 is VERY expensive
 183          * 2. If several processes do updates in parallel and then read the
 184          *    hypfs data, the likelihood of collisions is reduced, if we restrict
 185          *    the minimum update interval. A collision occurs, if during the
 186          *    data gathering of one process another process triggers an update
 187          *    If the first process wants to ensure consistent data, it has
 188          *    to restart data collection in this case.
 189          */
 190         mutex_lock(&fs_info->lock);
 191         if (fs_info->last_update == get_seconds()) {
 192                 rc = -EBUSY;
 193                 goto out;
 194         }
 195         hypfs_delete_tree(sb->s_root);
 196         if (MACHINE_IS_VM)
 197                 rc = hypfs_vm_create_files(sb, sb->s_root);
 198         else
 199                 rc = hypfs_diag_create_files(sb, sb->s_root);
 200         if (rc) {
 201                 printk(KERN_ERR "hypfs: Update failed\n");
 202                 hypfs_delete_tree(sb->s_root);
 203                 goto out;
 204         }
 205         hypfs_update_update(sb);
 206         rc = count;
 207 out:
 208         mutex_unlock(&fs_info->lock);
 209         return rc;
 210 }
 211
 212 static int hypfs_release(struct inode *inode, struct file *filp)
 213 {
 214         kfree(filp->private_data);
 215         return 0;
 216 }
 217
 218 enum { opt_uid, opt_gid, opt_err };
 219
 220 static match_table_t hypfs_tokens = {
 221         {opt_uid, "uid=%u"},
 222         {opt_gid, "gid=%u"},
 223         {opt_err, NULL}
 224 };
 225
 226 static int hypfs_parse_options(char *options, struct super_block *sb)
 227 {
 228         char *str;
 229         substring_t args[MAX_OPT_ARGS];
 230
 231         if (!options)
 232                 return 0;
 233         while ((str = strsep(&options, ",")) != NULL) {
 234                 int token, option;
 235                 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
 236
 237                 if (!*str)
 238                         continue;
 239                 token = match_token(str, hypfs_tokens, args);
 240                 switch (token) {
 241                 case opt_uid:
 242                         if (match_int(&args[0], &option))
 243                                 return -EINVAL;
 244                         hypfs_info->uid = option;
 245                         break;
 246                 case opt_gid:
 247                         if (match_int(&args[0], &option))
 248                                 return -EINVAL;
 249                         hypfs_info->gid = option;
 250                         break;
 251                 case opt_err:
 252                 default:
 253                         printk(KERN_ERR "hypfs: Unrecognized mount option "
 254                                "\"%s\" or missing value\n", str);
 255                         return -EINVAL;
 256                 }
 257         }
 258         return 0;
 259 }
 260
 261 static int hypfs_show_options(struct seq_file *s, struct vfsmount *mnt)
 262 {
 263         struct hypfs_sb_info *hypfs_info = mnt->mnt_sb->s_fs_info;
 264
 265         seq_printf(s, ",uid=%u", hypfs_info->uid);
 266         seq_printf(s, ",gid=%u", hypfs_info->gid);
 267         return 0;
 268 }
 269
 270 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
 271 {
 272         struct inode *root_inode;
 273         struct dentry *root_dentry;
 274         int rc = 0;
 275         struct hypfs_sb_info *sbi;
 276
 277         sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
 278         if (!sbi)
 279                 return -ENOMEM;
 280         mutex_init(&sbi->lock);
 281         sbi->uid = current->uid;
 282         sbi->gid = current->gid;
 283         sb->s_fs_info = sbi;
 284         sb->s_blocksize = PAGE_CACHE_SIZE;
 285         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 286         sb->s_magic = HYPFS_MAGIC;
 287         sb->s_op = &hypfs_s_ops;
 288         if (hypfs_parse_options(data, sb)) {
 289                 rc = -EINVAL;
 290                 goto err_alloc;
 291         }
 292         root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
 293         if (!root_inode) {
 294                 rc = -ENOMEM;
 295                 goto err_alloc;
 296         }
 297         root_inode->i_op = &simple_dir_inode_operations;
 298         root_inode->i_fop = &simple_dir_operations;
 299         root_dentry = d_alloc_root(root_inode);
 300         if (!root_dentry) {
 301                 iput(root_inode);
 302                 rc = -ENOMEM;
 303                 goto err_alloc;
 304         }
 305         if (MACHINE_IS_VM)
 306                 rc = hypfs_vm_create_files(sb, root_dentry);
 307         else
 308                 rc = hypfs_diag_create_files(sb, root_dentry);
 309         if (rc)
 310                 goto err_tree;
 311         sbi->update_file = hypfs_create_update_file(sb, root_dentry);
 312         if (IS_ERR(sbi->update_file)) {
 313                 rc = PTR_ERR(sbi->update_file);
 314                 goto err_tree;
 315         }
 316         hypfs_update_update(sb);
 317         sb->s_root = root_dentry;
 318         return 0;
 319
 320 err_tree:
 321         hypfs_delete_tree(root_dentry);
 322         d_genocide(root_dentry);
 323         dput(root_dentry);
 324 err_alloc:
 325         kfree(sbi);
 326         return rc;
 327 }
 328
 329 static int hypfs_get_super(struct file_system_type *fst, int flags,
 330                         const char *devname, void *data, struct vfsmount *mnt)
 331 {
 332         return get_sb_single(fst, flags, data, hypfs_fill_super, mnt);
 333 }
 334
 335 static void hypfs_kill_super(struct super_block *sb)
 336 {
 337         struct hypfs_sb_info *sb_info = sb->s_fs_info;
 338
 339         if (sb->s_root) {
 340                 hypfs_delete_tree(sb->s_root);
 341                 hypfs_remove(sb_info->update_file);
 342                 kfree(sb->s_fs_info);
 343                 sb->s_fs_info = NULL;
 344         }
 345         kill_litter_super(sb);
 346 }
 347
 348 static struct dentry *hypfs_create_file(struct super_block *sb,
 349                                         struct dentry *parent, const char *name,
 350                                         char *data, mode_t mode)
 351 {
 352         struct dentry *dentry;
 353         struct inode *inode;
 354         struct qstr qname;
 355
 356         qname.name = name;
 357         qname.len = strlen(name);
 358         qname.hash = full_name_hash(name, qname.len);
 359         dentry = lookup_one_len(name, parent, strlen(name));
 360         if (IS_ERR(dentry))
 361                 return ERR_PTR(-ENOMEM);
 362         inode = hypfs_make_inode(sb, mode);
 363         if (!inode) {
 364                 dput(dentry);
 365                 return ERR_PTR(-ENOMEM);
 366         }
 367         if (mode & S_IFREG) {
 368                 inode->i_fop = &hypfs_file_ops;
 369                 if (data)
 370                         inode->i_size = strlen(data);
 371                 else
 372                         inode->i_size = 0;
 373         } else if (mode & S_IFDIR) {
 374                 inode->i_op = &simple_dir_inode_operations;
 375                 inode->i_fop = &simple_dir_operations;
 376                 parent->d_inode->i_nlink++;
 377         } else
 378                 BUG();
 379         inode->i_private = data;
 380         d_instantiate(dentry, inode);
 381         dget(dentry);
 382         return dentry;
 383 }
 384
 385 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
 386                            const char *name)
 387 {
 388         struct dentry *dentry;
 389
 390         dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
 391         if (IS_ERR(dentry))
 392                 return dentry;
 393         hypfs_add_dentry(dentry);
 394         parent->d_inode->i_nlink++;
 395         return dentry;
 396 }
 397
 398 static struct dentry *hypfs_create_update_file(struct super_block *sb,
 399                                                struct dentry *dir)
 400 {
 401         struct dentry *dentry;
 402
 403         dentry = hypfs_create_file(sb, dir, "update", NULL,
 404                                    S_IFREG | UPDATE_FILE_MODE);
 405         /*
 406          * We do not put the update file on the 'delete' list with
 407          * hypfs_add_dentry(), since it should not be removed when the tree
 408          * is updated.
 409          */
 410         return dentry;
 411 }
 412
 413 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
 414                                 const char *name, __u64 value)
 415 {
 416         char *buffer;
 417         char tmp[TMP_SIZE];
 418         struct dentry *dentry;
 419
 420         snprintf(tmp, TMP_SIZE, "%lld\n", (unsigned long long int)value);
 421         buffer = kstrdup(tmp, GFP_KERNEL);
 422         if (!buffer)
 423                 return ERR_PTR(-ENOMEM);
 424         dentry =
 425             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
 426         if (IS_ERR(dentry)) {
 427                 kfree(buffer);
 428                 return ERR_PTR(-ENOMEM);
 429         }
 430         hypfs_add_dentry(dentry);
 431         return dentry;
 432 }
 433
 434 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
 435                                 const char *name, char *string)
 436 {
 437         char *buffer;
 438         struct dentry *dentry;
 439
 440         buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
 441         if (!buffer)
 442                 return ERR_PTR(-ENOMEM);
 443         sprintf(buffer, "%s\n", string);
 444         dentry =
 445             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
 446         if (IS_ERR(dentry)) {
 447                 kfree(buffer);
 448                 return ERR_PTR(-ENOMEM);
 449         }
 450         hypfs_add_dentry(dentry);
 451         return dentry;
 452 }
 453
 454 static const struct file_operations hypfs_file_ops = {
 455         .open           = hypfs_open,
 456         .release        = hypfs_release,
 457         .read           = do_sync_read,
 458         .write          = do_sync_write,
 459         .aio_read       = hypfs_aio_read,
 460         .aio_write      = hypfs_aio_write,
 461 };
 462
 463 static struct file_system_type hypfs_type = {
 464         .owner          = THIS_MODULE,
 465         .name           = "s390_hypfs",
 466         .get_sb         = hypfs_get_super,
 467         .kill_sb        = hypfs_kill_super
 468 };
 469
 470 static struct super_operations hypfs_s_ops = {
 471         .statfs         = simple_statfs,
 472         .drop_inode     = hypfs_drop_inode,
 473         .show_options   = hypfs_show_options,
 474 };
 475
 476 static decl_subsys(s390, NULL, NULL);
 477
 478 static int __init hypfs_init(void)
 479 {
 480         int rc;
 481
 482         if (MACHINE_IS_VM) {
 483                 if (hypfs_vm_init())
 484                         /* no diag 2fc, just exit */
 485                         return -ENODATA;
 486         } else {
 487                 if (hypfs_diag_init()) {
 488                         rc = -ENODATA;
 489                         goto fail_diag;
 490                 }
 491         }
 492         kobj_set_kset_s(&s390_subsys, hypervisor_subsys);
 493         rc = subsystem_register(&s390_subsys);
 494         if (rc)
 495                 goto fail_sysfs;
 496         rc = register_filesystem(&hypfs_type);
 497         if (rc)
 498                 goto fail_filesystem;
 499         return 0;
 500
 501 fail_filesystem:
 502         subsystem_unregister(&s390_subsys);
 503 fail_sysfs:
 504         if (!MACHINE_IS_VM)
 505                 hypfs_diag_exit();
 506 fail_diag:
 507         printk(KERN_ERR "hypfs: Initialization failed with rc = %i.\n", rc);
 508         return rc;
 509 }
 510
 511 static void __exit hypfs_exit(void)
 512 {
 513         if (!MACHINE_IS_VM)
 514                 hypfs_diag_exit();
 515         unregister_filesystem(&hypfs_type);
 516         subsystem_unregister(&s390_subsys);
 517 }
 518
 519 module_init(hypfs_init)
 520 module_exit(hypfs_exit)
 521
 522 MODULE_LICENSE("GPL");
 523 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
 524 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");