arch/s390/hypfs/inode.c

   1 /*
   2  *    Hypervisor filesystem for Linux on s390.
   3  *
   4  *    Copyright IBM Corp. 2006, 2008
   5  *    Author(s): Michael Holzheu <holzheu@de.ibm.com>
   6  */
   7
   8 #define KMSG_COMPONENT "hypfs"
   9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  10
  11 #include <linux/types.h>
  12 #include <linux/errno.h>
  13 #include <linux/fs.h>
  14 #include <linux/namei.h>
  15 #include <linux/vfs.h>
  16 #include <linux/slab.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/time.h>
  19 #include <linux/parser.h>
  20 #include <linux/sysfs.h>
  21 #include <linux/module.h>
  22 #include <linux/seq_file.h>
  23 #include <linux/mount.h>
  24 #include <asm/ebcdic.h>
  25 #include "hypfs.h"
  26
  27 #define HYPFS_MAGIC 0x687970    /* ASCII 'hyp' */
  28 #define TMP_SIZE 64             /* size of temporary buffers */
  29
  30 static struct dentry *hypfs_create_update_file(struct super_block *sb,
  31                                                struct dentry *dir);
  32
  33 struct hypfs_sb_info {
  34         kuid_t uid;                     /* uid used for files and dirs */
  35         kgid_t gid;                     /* gid used for files and dirs */
  36         struct dentry *update_file;     /* file to trigger update */
  37         time_t last_update;             /* last update time in secs since 1970 */
  38         struct mutex lock;              /* lock to protect update process */
  39 };
  40
  41 static const struct file_operations hypfs_file_ops;
  42 static struct file_system_type hypfs_type;
  43 static const struct super_operations hypfs_s_ops;
  44
  45 /* start of list of all dentries, which have to be deleted on update */
  46 static struct dentry *hypfs_last_dentry;
  47
  48 static void hypfs_update_update(struct super_block *sb)
  49 {
  50         struct hypfs_sb_info *sb_info = sb->s_fs_info;
  51         struct inode *inode = sb_info->update_file->d_inode;
  52
  53         sb_info->last_update = get_seconds();
  54         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
  55 }
  56
  57 /* directory tree removal functions */
  58
  59 static void hypfs_add_dentry(struct dentry *dentry)
  60 {
  61         dentry->d_fsdata = hypfs_last_dentry;
  62         hypfs_last_dentry = dentry;
  63 }
  64
  65 static inline int hypfs_positive(struct dentry *dentry)
  66 {
  67         return dentry->d_inode && !d_unhashed(dentry);
  68 }
  69
  70 static void hypfs_remove(struct dentry *dentry)
  71 {
  72         struct dentry *parent;
  73
  74         parent = dentry->d_parent;
  75         if (!parent || !parent->d_inode)
  76                 return;
  77         mutex_lock(&parent->d_inode->i_mutex);
  78         if (hypfs_positive(dentry)) {
  79                 if (S_ISDIR(dentry->d_inode->i_mode))
  80                         simple_rmdir(parent->d_inode, dentry);
  81                 else
  82                         simple_unlink(parent->d_inode, dentry);
  83         }
  84         d_delete(dentry);
  85         dput(dentry);
  86         mutex_unlock(&parent->d_inode->i_mutex);
  87 }
  88
  89 static void hypfs_delete_tree(struct dentry *root)
  90 {
  91         while (hypfs_last_dentry) {
  92                 struct dentry *next_dentry;
  93                 next_dentry = hypfs_last_dentry->d_fsdata;
  94                 hypfs_remove(hypfs_last_dentry);
  95                 hypfs_last_dentry = next_dentry;
  96         }
  97 }
  98
  99 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
 100 {
 101         struct inode *ret = new_inode(sb);
 102
 103         if (ret) {
 104                 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
 105                 ret->i_ino = get_next_ino();
 106                 ret->i_mode = mode;
 107                 ret->i_uid = hypfs_info->uid;
 108                 ret->i_gid = hypfs_info->gid;
 109                 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
 110                 if (S_ISDIR(mode))
 111                         set_nlink(ret, 2);
 112         }
 113         return ret;
 114 }
 115
 116 static void hypfs_evict_inode(struct inode *inode)
 117 {
 118         clear_inode(inode);
 119         kfree(inode->i_private);
 120 }
 121
 122 static int hypfs_open(struct inode *inode, struct file *filp)
 123 {
 124         char *data = filp->f_path.dentry->d_inode->i_private;
 125         struct hypfs_sb_info *fs_info;
 126
 127         if (filp->f_mode & FMODE_WRITE) {
 128                 if (!(inode->i_mode & S_IWUGO))
 129                         return -EACCES;
 130         }
 131         if (filp->f_mode & FMODE_READ) {
 132                 if (!(inode->i_mode & S_IRUGO))
 133                         return -EACCES;
 134         }
 135
 136         fs_info = inode->i_sb->s_fs_info;
 137         if(data) {
 138                 mutex_lock(&fs_info->lock);
 139                 filp->private_data = kstrdup(data, GFP_KERNEL);
 140                 if (!filp->private_data) {
 141                         mutex_unlock(&fs_info->lock);
 142                         return -ENOMEM;
 143                 }
 144                 mutex_unlock(&fs_info->lock);
 145         }
 146         return nonseekable_open(inode, filp);
 147 }
 148
 149 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
 150                               unsigned long nr_segs, loff_t offset)
 151 {
 152         char *data;
 153         ssize_t ret;
 154         struct file *filp = iocb->ki_filp;
 155         /* XXX: temporary */
 156         char __user *buf = iov[0].iov_base;
 157         size_t count = iov[0].iov_len;
 158
 159         if (nr_segs != 1)
 160                 return -EINVAL;
 161
 162         data = filp->private_data;
 163         ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
 164         if (ret <= 0)
 165                 return ret;
 166
 167         iocb->ki_pos += ret;
 168         file_accessed(filp);
 169
 170         return ret;
 171 }
 172 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
 173                               unsigned long nr_segs, loff_t offset)
 174 {
 175         int rc;
 176         struct super_block *sb;
 177         struct hypfs_sb_info *fs_info;
 178         size_t count = iov_length(iov, nr_segs);
 179
 180         sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb;
 181         fs_info = sb->s_fs_info;
 182         /*
 183          * Currently we only allow one update per second for two reasons:
 184          * 1. diag 204 is VERY expensive
 185          * 2. If several processes do updates in parallel and then read the
 186          *    hypfs data, the likelihood of collisions is reduced, if we restrict
 187          *    the minimum update interval. A collision occurs, if during the
 188          *    data gathering of one process another process triggers an update
 189          *    If the first process wants to ensure consistent data, it has
 190          *    to restart data collection in this case.
 191          */
 192         mutex_lock(&fs_info->lock);
 193         if (fs_info->last_update == get_seconds()) {
 194                 rc = -EBUSY;
 195                 goto out;
 196         }
 197         hypfs_delete_tree(sb->s_root);
 198         if (MACHINE_IS_VM)
 199                 rc = hypfs_vm_create_files(sb, sb->s_root);
 200         else
 201                 rc = hypfs_diag_create_files(sb, sb->s_root);
 202         if (rc) {
 203                 pr_err("Updating the hypfs tree failed\n");
 204                 hypfs_delete_tree(sb->s_root);
 205                 goto out;
 206         }
 207         hypfs_update_update(sb);
 208         rc = count;
 209 out:
 210         mutex_unlock(&fs_info->lock);
 211         return rc;
 212 }
 213
 214 static int hypfs_release(struct inode *inode, struct file *filp)
 215 {
 216         kfree(filp->private_data);
 217         return 0;
 218 }
 219
 220 enum { opt_uid, opt_gid, opt_err };
 221
 222 static const match_table_t hypfs_tokens = {
 223         {opt_uid, "uid=%u"},
 224         {opt_gid, "gid=%u"},
 225         {opt_err, NULL}
 226 };
 227
 228 static int hypfs_parse_options(char *options, struct super_block *sb)
 229 {
 230         char *str;
 231         substring_t args[MAX_OPT_ARGS];
 232         kuid_t uid;
 233         kgid_t gid;
 234
 235         if (!options)
 236                 return 0;
 237         while ((str = strsep(&options, ",")) != NULL) {
 238                 int token, option;
 239                 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
 240
 241                 if (!*str)
 242                         continue;
 243                 token = match_token(str, hypfs_tokens, args);
 244                 switch (token) {
 245                 case opt_uid:
 246                         if (match_int(&args[0], &option))
 247                                 return -EINVAL;
 248                         uid = make_kuid(current_user_ns(), option);
 249                         if (!uid_valid(uid))
 250                                 return -EINVAL;
 251                         hypfs_info->uid = uid;
 252                         break;
 253                 case opt_gid:
 254                         if (match_int(&args[0], &option))
 255                                 return -EINVAL;
 256                         gid = make_kgid(current_user_ns(), option);
 257                         if (!gid_valid(gid))
 258                                 return -EINVAL;
 259                         hypfs_info->gid = gid;
 260                         break;
 261                 case opt_err:
 262                 default:
 263                         pr_err("%s is not a valid mount option\n", str);
 264                         return -EINVAL;
 265                 }
 266         }
 267         return 0;
 268 }
 269
 270 static int hypfs_show_options(struct seq_file *s, struct dentry *root)
 271 {
 272         struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;
 273
 274         seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid));
 275         seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid));
 276         return 0;
 277 }
 278
 279 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
 280 {
 281         struct inode *root_inode;
 282         struct dentry *root_dentry;
 283         int rc = 0;
 284         struct hypfs_sb_info *sbi;
 285
 286         sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
 287         if (!sbi)
 288                 return -ENOMEM;
 289         mutex_init(&sbi->lock);
 290         sbi->uid = current_uid();
 291         sbi->gid = current_gid();
 292         sb->s_fs_info = sbi;
 293         sb->s_blocksize = PAGE_CACHE_SIZE;
 294         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 295         sb->s_magic = HYPFS_MAGIC;
 296         sb->s_op = &hypfs_s_ops;
 297         if (hypfs_parse_options(data, sb))
 298                 return -EINVAL;
 299         root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
 300         if (!root_inode)
 301                 return -ENOMEM;
 302         root_inode->i_op = &simple_dir_inode_operations;
 303         root_inode->i_fop = &simple_dir_operations;
 304         sb->s_root = root_dentry = d_make_root(root_inode);
 305         if (!root_dentry)
 306                 return -ENOMEM;
 307         if (MACHINE_IS_VM)
 308                 rc = hypfs_vm_create_files(sb, root_dentry);
 309         else
 310                 rc = hypfs_diag_create_files(sb, root_dentry);
 311         if (rc)
 312                 return rc;
 313         sbi->update_file = hypfs_create_update_file(sb, root_dentry);
 314         if (IS_ERR(sbi->update_file))
 315                 return PTR_ERR(sbi->update_file);
 316         hypfs_update_update(sb);
 317         pr_info("Hypervisor filesystem mounted\n");
 318         return 0;
 319 }
 320
 321 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags,
 322                         const char *devname, void *data)
 323 {
 324         return mount_single(fst, flags, data, hypfs_fill_super);
 325 }
 326
 327 static void hypfs_kill_super(struct super_block *sb)
 328 {
 329         struct hypfs_sb_info *sb_info = sb->s_fs_info;
 330
 331         if (sb->s_root)
 332                 hypfs_delete_tree(sb->s_root);
 333         if (sb_info->update_file)
 334                 hypfs_remove(sb_info->update_file);
 335         kfree(sb->s_fs_info);
 336         sb->s_fs_info = NULL;
 337         kill_litter_super(sb);
 338 }
 339
 340 static struct dentry *hypfs_create_file(struct super_block *sb,
 341                                         struct dentry *parent, const char *name,
 342                                         char *data, umode_t mode)
 343 {
 344         struct dentry *dentry;
 345         struct inode *inode;
 346
 347         mutex_lock(&parent->d_inode->i_mutex);
 348         dentry = lookup_one_len(name, parent, strlen(name));
 349         if (IS_ERR(dentry)) {
 350                 dentry = ERR_PTR(-ENOMEM);
 351                 goto fail;
 352         }
 353         inode = hypfs_make_inode(sb, mode);
 354         if (!inode) {
 355                 dput(dentry);
 356                 dentry = ERR_PTR(-ENOMEM);
 357                 goto fail;
 358         }
 359         if (S_ISREG(mode)) {
 360                 inode->i_fop = &hypfs_file_ops;
 361                 if (data)
 362                         inode->i_size = strlen(data);
 363                 else
 364                         inode->i_size = 0;
 365         } else if (S_ISDIR(mode)) {
 366                 inode->i_op = &simple_dir_inode_operations;
 367                 inode->i_fop = &simple_dir_operations;
 368                 inc_nlink(parent->d_inode);
 369         } else
 370                 BUG();
 371         inode->i_private = data;
 372         d_instantiate(dentry, inode);
 373         dget(dentry);
 374 fail:
 375         mutex_unlock(&parent->d_inode->i_mutex);
 376         return dentry;
 377 }
 378
 379 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
 380                            const char *name)
 381 {
 382         struct dentry *dentry;
 383
 384         dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
 385         if (IS_ERR(dentry))
 386                 return dentry;
 387         hypfs_add_dentry(dentry);
 388         return dentry;
 389 }
 390
 391 static struct dentry *hypfs_create_update_file(struct super_block *sb,
 392                                                struct dentry *dir)
 393 {
 394         struct dentry *dentry;
 395
 396         dentry = hypfs_create_file(sb, dir, "update", NULL,
 397                                    S_IFREG | UPDATE_FILE_MODE);
 398         /*
 399          * We do not put the update file on the 'delete' list with
 400          * hypfs_add_dentry(), since it should not be removed when the tree
 401          * is updated.
 402          */
 403         return dentry;
 404 }
 405
 406 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
 407                                 const char *name, __u64 value)
 408 {
 409         char *buffer;
 410         char tmp[TMP_SIZE];
 411         struct dentry *dentry;
 412
 413         snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
 414         buffer = kstrdup(tmp, GFP_KERNEL);
 415         if (!buffer)
 416                 return ERR_PTR(-ENOMEM);
 417         dentry =
 418             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
 419         if (IS_ERR(dentry)) {
 420                 kfree(buffer);
 421                 return ERR_PTR(-ENOMEM);
 422         }
 423         hypfs_add_dentry(dentry);
 424         return dentry;
 425 }
 426
 427 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
 428                                 const char *name, char *string)
 429 {
 430         char *buffer;
 431         struct dentry *dentry;
 432
 433         buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
 434         if (!buffer)
 435                 return ERR_PTR(-ENOMEM);
 436         sprintf(buffer, "%s\n", string);
 437         dentry =
 438             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
 439         if (IS_ERR(dentry)) {
 440                 kfree(buffer);
 441                 return ERR_PTR(-ENOMEM);
 442         }
 443         hypfs_add_dentry(dentry);
 444         return dentry;
 445 }
 446
 447 static const struct file_operations hypfs_file_ops = {
 448         .open           = hypfs_open,
 449         .release        = hypfs_release,
 450         .read           = do_sync_read,
 451         .write          = do_sync_write,
 452         .aio_read       = hypfs_aio_read,
 453         .aio_write      = hypfs_aio_write,
 454         .llseek         = no_llseek,
 455 };
 456
 457 static struct file_system_type hypfs_type = {
 458         .owner          = THIS_MODULE,
 459         .name           = "s390_hypfs",
 460         .mount          = hypfs_mount,
 461         .kill_sb        = hypfs_kill_super
 462 };
 463
 464 static const struct super_operations hypfs_s_ops = {
 465         .statfs         = simple_statfs,
 466         .evict_inode    = hypfs_evict_inode,
 467         .show_options   = hypfs_show_options,
 468 };
 469
 470 static struct kobject *s390_kobj;
 471
 472 static int __init hypfs_init(void)
 473 {
 474         int rc;
 475
 476         rc = hypfs_dbfs_init();
 477         if (rc)
 478                 return rc;
 479         if (hypfs_diag_init()) {
 480                 rc = -ENODATA;
 481                 goto fail_dbfs_exit;
 482         }
 483         if (hypfs_vm_init()) {
 484                 rc = -ENODATA;
 485                 goto fail_hypfs_diag_exit;
 486         }
 487         s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
 488         if (!s390_kobj) {
 489                 rc = -ENOMEM;
 490                 goto fail_hypfs_vm_exit;
 491         }
 492         rc = register_filesystem(&hypfs_type);
 493         if (rc)
 494                 goto fail_filesystem;
 495         return 0;
 496
 497 fail_filesystem:
 498         kobject_put(s390_kobj);
 499 fail_hypfs_vm_exit:
 500         hypfs_vm_exit();
 501 fail_hypfs_diag_exit:
 502         hypfs_diag_exit();
 503 fail_dbfs_exit:
 504         hypfs_dbfs_exit();
 505         pr_err("Initialization of hypfs failed with rc=%i\n", rc);
 506         return rc;
 507 }
 508
 509 static void __exit hypfs_exit(void)
 510 {
 511         hypfs_diag_exit();
 512         hypfs_vm_exit();
 513         hypfs_dbfs_exit();
 514         unregister_filesystem(&hypfs_type);
 515         kobject_put(s390_kobj);
 516 }
 517
 518 module_init(hypfs_init)
 519 module_exit(hypfs_exit)
 520
 521 MODULE_LICENSE("GPL");
 522 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
 523 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");