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