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 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 mutex_lock(&parent->d_inode->i_mutex); 76 if (hypfs_positive(dentry)) { 77 if (d_is_dir(dentry)) 78 simple_rmdir(parent->d_inode, dentry); 79 else 80 simple_unlink(parent->d_inode, dentry); 81 } 82 d_delete(dentry); 83 dput(dentry); 84 mutex_unlock(&parent->d_inode->i_mutex); 85 } 86 87 static void hypfs_delete_tree(struct dentry *root) 88 { 89 while (hypfs_last_dentry) { 90 struct dentry *next_dentry; 91 next_dentry = hypfs_last_dentry->d_fsdata; 92 hypfs_remove(hypfs_last_dentry); 93 hypfs_last_dentry = next_dentry; 94 } 95 } 96 97 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode) 98 { 99 struct inode *ret = new_inode(sb); 100 101 if (ret) { 102 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 103 ret->i_ino = get_next_ino(); 104 ret->i_mode = mode; 105 ret->i_uid = hypfs_info->uid; 106 ret->i_gid = hypfs_info->gid; 107 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME; 108 if (S_ISDIR(mode)) 109 set_nlink(ret, 2); 110 } 111 return ret; 112 } 113 114 static void hypfs_evict_inode(struct inode *inode) 115 { 116 clear_inode(inode); 117 kfree(inode->i_private); 118 } 119 120 static int hypfs_open(struct inode *inode, struct file *filp) 121 { 122 char *data = file_inode(filp)->i_private; 123 struct hypfs_sb_info *fs_info; 124 125 if (filp->f_mode & FMODE_WRITE) { 126 if (!(inode->i_mode & S_IWUGO)) 127 return -EACCES; 128 } 129 if (filp->f_mode & FMODE_READ) { 130 if (!(inode->i_mode & S_IRUGO)) 131 return -EACCES; 132 } 133 134 fs_info = inode->i_sb->s_fs_info; 135 if(data) { 136 mutex_lock(&fs_info->lock); 137 filp->private_data = kstrdup(data, GFP_KERNEL); 138 if (!filp->private_data) { 139 mutex_unlock(&fs_info->lock); 140 return -ENOMEM; 141 } 142 mutex_unlock(&fs_info->lock); 143 } 144 return nonseekable_open(inode, filp); 145 } 146 147 static ssize_t hypfs_read_iter(struct kiocb *iocb, struct iov_iter *to) 148 { 149 struct file *file = iocb->ki_filp; 150 char *data = file->private_data; 151 size_t available = strlen(data); 152 loff_t pos = iocb->ki_pos; 153 size_t count; 154 155 if (pos < 0) 156 return -EINVAL; 157 if (pos >= available || !iov_iter_count(to)) 158 return 0; 159 count = copy_to_iter(data + pos, available - pos, to); 160 if (!count) 161 return -EFAULT; 162 iocb->ki_pos = pos + count; 163 file_accessed(file); 164 return count; 165 } 166 167 static ssize_t hypfs_write_iter(struct kiocb *iocb, struct iov_iter *from) 168 { 169 int rc; 170 struct super_block *sb = file_inode(iocb->ki_filp)->i_sb; 171 struct hypfs_sb_info *fs_info = sb->s_fs_info; 172 size_t count = iov_iter_count(from); 173 174 /* 175 * Currently we only allow one update per second for two reasons: 176 * 1. diag 204 is VERY expensive 177 * 2. If several processes do updates in parallel and then read the 178 * hypfs data, the likelihood of collisions is reduced, if we restrict 179 * the minimum update interval. A collision occurs, if during the 180 * data gathering of one process another process triggers an update 181 * If the first process wants to ensure consistent data, it has 182 * to restart data collection in this case. 183 */ 184 mutex_lock(&fs_info->lock); 185 if (fs_info->last_update == get_seconds()) { 186 rc = -EBUSY; 187 goto out; 188 } 189 hypfs_delete_tree(sb->s_root); 190 if (MACHINE_IS_VM) 191 rc = hypfs_vm_create_files(sb->s_root); 192 else 193 rc = hypfs_diag_create_files(sb->s_root); 194 if (rc) { 195 pr_err("Updating the hypfs tree failed\n"); 196 hypfs_delete_tree(sb->s_root); 197 goto out; 198 } 199 hypfs_update_update(sb); 200 rc = count; 201 iov_iter_advance(from, count); 202 out: 203 mutex_unlock(&fs_info->lock); 204 return rc; 205 } 206 207 static int hypfs_release(struct inode *inode, struct file *filp) 208 { 209 kfree(filp->private_data); 210 return 0; 211 } 212 213 enum { opt_uid, opt_gid, opt_err }; 214 215 static const match_table_t hypfs_tokens = { 216 {opt_uid, "uid=%u"}, 217 {opt_gid, "gid=%u"}, 218 {opt_err, NULL} 219 }; 220 221 static int hypfs_parse_options(char *options, struct super_block *sb) 222 { 223 char *str; 224 substring_t args[MAX_OPT_ARGS]; 225 kuid_t uid; 226 kgid_t gid; 227 228 if (!options) 229 return 0; 230 while ((str = strsep(&options, ",")) != NULL) { 231 int token, option; 232 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 233 234 if (!*str) 235 continue; 236 token = match_token(str, hypfs_tokens, args); 237 switch (token) { 238 case opt_uid: 239 if (match_int(&args[0], &option)) 240 return -EINVAL; 241 uid = make_kuid(current_user_ns(), option); 242 if (!uid_valid(uid)) 243 return -EINVAL; 244 hypfs_info->uid = uid; 245 break; 246 case opt_gid: 247 if (match_int(&args[0], &option)) 248 return -EINVAL; 249 gid = make_kgid(current_user_ns(), option); 250 if (!gid_valid(gid)) 251 return -EINVAL; 252 hypfs_info->gid = gid; 253 break; 254 case opt_err: 255 default: 256 pr_err("%s is not a valid mount option\n", str); 257 return -EINVAL; 258 } 259 } 260 return 0; 261 } 262 263 static int hypfs_show_options(struct seq_file *s, struct dentry *root) 264 { 265 struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info; 266 267 seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid)); 268 seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid)); 269 return 0; 270 } 271 272 static int hypfs_fill_super(struct super_block *sb, void *data, int silent) 273 { 274 struct inode *root_inode; 275 struct dentry *root_dentry; 276 int rc = 0; 277 struct hypfs_sb_info *sbi; 278 279 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); 280 if (!sbi) 281 return -ENOMEM; 282 mutex_init(&sbi->lock); 283 sbi->uid = current_uid(); 284 sbi->gid = current_gid(); 285 sb->s_fs_info = sbi; 286 sb->s_blocksize = PAGE_CACHE_SIZE; 287 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 288 sb->s_magic = HYPFS_MAGIC; 289 sb->s_op = &hypfs_s_ops; 290 if (hypfs_parse_options(data, sb)) 291 return -EINVAL; 292 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755); 293 if (!root_inode) 294 return -ENOMEM; 295 root_inode->i_op = &simple_dir_inode_operations; 296 root_inode->i_fop = &simple_dir_operations; 297 sb->s_root = root_dentry = d_make_root(root_inode); 298 if (!root_dentry) 299 return -ENOMEM; 300 if (MACHINE_IS_VM) 301 rc = hypfs_vm_create_files(root_dentry); 302 else 303 rc = hypfs_diag_create_files(root_dentry); 304 if (rc) 305 return rc; 306 sbi->update_file = hypfs_create_update_file(root_dentry); 307 if (IS_ERR(sbi->update_file)) 308 return PTR_ERR(sbi->update_file); 309 hypfs_update_update(sb); 310 pr_info("Hypervisor filesystem mounted\n"); 311 return 0; 312 } 313 314 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags, 315 const char *devname, void *data) 316 { 317 return mount_single(fst, flags, data, hypfs_fill_super); 318 } 319 320 static void hypfs_kill_super(struct super_block *sb) 321 { 322 struct hypfs_sb_info *sb_info = sb->s_fs_info; 323 324 if (sb->s_root) 325 hypfs_delete_tree(sb->s_root); 326 if (sb_info->update_file) 327 hypfs_remove(sb_info->update_file); 328 kfree(sb->s_fs_info); 329 sb->s_fs_info = NULL; 330 kill_litter_super(sb); 331 } 332 333 static struct dentry *hypfs_create_file(struct dentry *parent, const char *name, 334 char *data, umode_t mode) 335 { 336 struct dentry *dentry; 337 struct inode *inode; 338 339 mutex_lock(&parent->d_inode->i_mutex); 340 dentry = lookup_one_len(name, parent, strlen(name)); 341 if (IS_ERR(dentry)) { 342 dentry = ERR_PTR(-ENOMEM); 343 goto fail; 344 } 345 inode = hypfs_make_inode(parent->d_sb, mode); 346 if (!inode) { 347 dput(dentry); 348 dentry = ERR_PTR(-ENOMEM); 349 goto fail; 350 } 351 if (S_ISREG(mode)) { 352 inode->i_fop = &hypfs_file_ops; 353 if (data) 354 inode->i_size = strlen(data); 355 else 356 inode->i_size = 0; 357 } else if (S_ISDIR(mode)) { 358 inode->i_op = &simple_dir_inode_operations; 359 inode->i_fop = &simple_dir_operations; 360 inc_nlink(parent->d_inode); 361 } else 362 BUG(); 363 inode->i_private = data; 364 d_instantiate(dentry, inode); 365 dget(dentry); 366 fail: 367 mutex_unlock(&parent->d_inode->i_mutex); 368 return dentry; 369 } 370 371 struct dentry *hypfs_mkdir(struct dentry *parent, const char *name) 372 { 373 struct dentry *dentry; 374 375 dentry = hypfs_create_file(parent, name, NULL, S_IFDIR | DIR_MODE); 376 if (IS_ERR(dentry)) 377 return dentry; 378 hypfs_add_dentry(dentry); 379 return dentry; 380 } 381 382 static struct dentry *hypfs_create_update_file(struct dentry *dir) 383 { 384 struct dentry *dentry; 385 386 dentry = hypfs_create_file(dir, "update", NULL, 387 S_IFREG | UPDATE_FILE_MODE); 388 /* 389 * We do not put the update file on the 'delete' list with 390 * hypfs_add_dentry(), since it should not be removed when the tree 391 * is updated. 392 */ 393 return dentry; 394 } 395 396 struct dentry *hypfs_create_u64(struct dentry *dir, 397 const char *name, __u64 value) 398 { 399 char *buffer; 400 char tmp[TMP_SIZE]; 401 struct dentry *dentry; 402 403 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value); 404 buffer = kstrdup(tmp, GFP_KERNEL); 405 if (!buffer) 406 return ERR_PTR(-ENOMEM); 407 dentry = 408 hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE); 409 if (IS_ERR(dentry)) { 410 kfree(buffer); 411 return ERR_PTR(-ENOMEM); 412 } 413 hypfs_add_dentry(dentry); 414 return dentry; 415 } 416 417 struct dentry *hypfs_create_str(struct dentry *dir, 418 const char *name, char *string) 419 { 420 char *buffer; 421 struct dentry *dentry; 422 423 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); 424 if (!buffer) 425 return ERR_PTR(-ENOMEM); 426 sprintf(buffer, "%s\n", string); 427 dentry = 428 hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE); 429 if (IS_ERR(dentry)) { 430 kfree(buffer); 431 return ERR_PTR(-ENOMEM); 432 } 433 hypfs_add_dentry(dentry); 434 return dentry; 435 } 436 437 static const struct file_operations hypfs_file_ops = { 438 .open = hypfs_open, 439 .release = hypfs_release, 440 .read = new_sync_read, 441 .write = new_sync_write, 442 .read_iter = hypfs_read_iter, 443 .write_iter = hypfs_write_iter, 444 .llseek = no_llseek, 445 }; 446 447 static struct file_system_type hypfs_type = { 448 .owner = THIS_MODULE, 449 .name = "s390_hypfs", 450 .mount = hypfs_mount, 451 .kill_sb = hypfs_kill_super 452 }; 453 MODULE_ALIAS_FS("s390_hypfs"); 454 455 static const struct super_operations hypfs_s_ops = { 456 .statfs = simple_statfs, 457 .evict_inode = hypfs_evict_inode, 458 .show_options = hypfs_show_options, 459 }; 460 461 static struct kobject *s390_kobj; 462 463 static int __init hypfs_init(void) 464 { 465 int rc; 466 467 rc = hypfs_dbfs_init(); 468 if (rc) 469 return rc; 470 if (hypfs_diag_init()) { 471 rc = -ENODATA; 472 goto fail_dbfs_exit; 473 } 474 if (hypfs_vm_init()) { 475 rc = -ENODATA; 476 goto fail_hypfs_diag_exit; 477 } 478 if (hypfs_sprp_init()) { 479 rc = -ENODATA; 480 goto fail_hypfs_vm_exit; 481 } 482 if (hypfs_diag0c_init()) { 483 rc = -ENODATA; 484 goto fail_hypfs_sprp_exit; 485 } 486 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj); 487 if (!s390_kobj) { 488 rc = -ENOMEM; 489 goto fail_hypfs_diag0c_exit; 490 } 491 rc = register_filesystem(&hypfs_type); 492 if (rc) 493 goto fail_filesystem; 494 return 0; 495 496 fail_filesystem: 497 kobject_put(s390_kobj); 498 fail_hypfs_diag0c_exit: 499 hypfs_diag0c_exit(); 500 fail_hypfs_sprp_exit: 501 hypfs_sprp_exit(); 502 fail_hypfs_vm_exit: 503 hypfs_vm_exit(); 504 fail_hypfs_diag_exit: 505 hypfs_diag_exit(); 506 fail_dbfs_exit: 507 hypfs_dbfs_exit(); 508 pr_err("Initialization of hypfs failed with rc=%i\n", rc); 509 return rc; 510 } 511 512 static void __exit hypfs_exit(void) 513 { 514 unregister_filesystem(&hypfs_type); 515 kobject_put(s390_kobj); 516 hypfs_diag0c_exit(); 517 hypfs_sprp_exit(); 518 hypfs_vm_exit(); 519 hypfs_diag_exit(); 520 hypfs_dbfs_exit(); 521 } 522 523 module_init(hypfs_init) 524 module_exit(hypfs_exit) 525 526 MODULE_LICENSE("GPL"); 527 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>"); 528 MODULE_DESCRIPTION("s390 Hypervisor Filesystem"); 529