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/uio.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 = d_inode(sb_info->update_file); 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 void hypfs_remove(struct dentry *dentry) 66 { 67 struct dentry *parent; 68 69 parent = dentry->d_parent; 70 mutex_lock(&d_inode(parent)->i_mutex); 71 if (simple_positive(dentry)) { 72 if (d_is_dir(dentry)) 73 simple_rmdir(d_inode(parent), dentry); 74 else 75 simple_unlink(d_inode(parent), dentry); 76 } 77 d_delete(dentry); 78 dput(dentry); 79 mutex_unlock(&d_inode(parent)->i_mutex); 80 } 81 82 static void hypfs_delete_tree(struct dentry *root) 83 { 84 while (hypfs_last_dentry) { 85 struct dentry *next_dentry; 86 next_dentry = hypfs_last_dentry->d_fsdata; 87 hypfs_remove(hypfs_last_dentry); 88 hypfs_last_dentry = next_dentry; 89 } 90 } 91 92 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode) 93 { 94 struct inode *ret = new_inode(sb); 95 96 if (ret) { 97 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 98 ret->i_ino = get_next_ino(); 99 ret->i_mode = mode; 100 ret->i_uid = hypfs_info->uid; 101 ret->i_gid = hypfs_info->gid; 102 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME; 103 if (S_ISDIR(mode)) 104 set_nlink(ret, 2); 105 } 106 return ret; 107 } 108 109 static void hypfs_evict_inode(struct inode *inode) 110 { 111 clear_inode(inode); 112 kfree(inode->i_private); 113 } 114 115 static int hypfs_open(struct inode *inode, struct file *filp) 116 { 117 char *data = file_inode(filp)->i_private; 118 struct hypfs_sb_info *fs_info; 119 120 if (filp->f_mode & FMODE_WRITE) { 121 if (!(inode->i_mode & S_IWUGO)) 122 return -EACCES; 123 } 124 if (filp->f_mode & FMODE_READ) { 125 if (!(inode->i_mode & S_IRUGO)) 126 return -EACCES; 127 } 128 129 fs_info = inode->i_sb->s_fs_info; 130 if(data) { 131 mutex_lock(&fs_info->lock); 132 filp->private_data = kstrdup(data, GFP_KERNEL); 133 if (!filp->private_data) { 134 mutex_unlock(&fs_info->lock); 135 return -ENOMEM; 136 } 137 mutex_unlock(&fs_info->lock); 138 } 139 return nonseekable_open(inode, filp); 140 } 141 142 static ssize_t hypfs_read_iter(struct kiocb *iocb, struct iov_iter *to) 143 { 144 struct file *file = iocb->ki_filp; 145 char *data = file->private_data; 146 size_t available = strlen(data); 147 loff_t pos = iocb->ki_pos; 148 size_t count; 149 150 if (pos < 0) 151 return -EINVAL; 152 if (pos >= available || !iov_iter_count(to)) 153 return 0; 154 count = copy_to_iter(data + pos, available - pos, to); 155 if (!count) 156 return -EFAULT; 157 iocb->ki_pos = pos + count; 158 file_accessed(file); 159 return count; 160 } 161 162 static ssize_t hypfs_write_iter(struct kiocb *iocb, struct iov_iter *from) 163 { 164 int rc; 165 struct super_block *sb = file_inode(iocb->ki_filp)->i_sb; 166 struct hypfs_sb_info *fs_info = sb->s_fs_info; 167 size_t count = iov_iter_count(from); 168 169 /* 170 * Currently we only allow one update per second for two reasons: 171 * 1. diag 204 is VERY expensive 172 * 2. If several processes do updates in parallel and then read the 173 * hypfs data, the likelihood of collisions is reduced, if we restrict 174 * the minimum update interval. A collision occurs, if during the 175 * data gathering of one process another process triggers an update 176 * If the first process wants to ensure consistent data, it has 177 * to restart data collection in this case. 178 */ 179 mutex_lock(&fs_info->lock); 180 if (fs_info->last_update == get_seconds()) { 181 rc = -EBUSY; 182 goto out; 183 } 184 hypfs_delete_tree(sb->s_root); 185 if (MACHINE_IS_VM) 186 rc = hypfs_vm_create_files(sb->s_root); 187 else 188 rc = hypfs_diag_create_files(sb->s_root); 189 if (rc) { 190 pr_err("Updating the hypfs tree failed\n"); 191 hypfs_delete_tree(sb->s_root); 192 goto out; 193 } 194 hypfs_update_update(sb); 195 rc = count; 196 iov_iter_advance(from, count); 197 out: 198 mutex_unlock(&fs_info->lock); 199 return rc; 200 } 201 202 static int hypfs_release(struct inode *inode, struct file *filp) 203 { 204 kfree(filp->private_data); 205 return 0; 206 } 207 208 enum { opt_uid, opt_gid, opt_err }; 209 210 static const match_table_t hypfs_tokens = { 211 {opt_uid, "uid=%u"}, 212 {opt_gid, "gid=%u"}, 213 {opt_err, NULL} 214 }; 215 216 static int hypfs_parse_options(char *options, struct super_block *sb) 217 { 218 char *str; 219 substring_t args[MAX_OPT_ARGS]; 220 kuid_t uid; 221 kgid_t gid; 222 223 if (!options) 224 return 0; 225 while ((str = strsep(&options, ",")) != NULL) { 226 int token, option; 227 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 228 229 if (!*str) 230 continue; 231 token = match_token(str, hypfs_tokens, args); 232 switch (token) { 233 case opt_uid: 234 if (match_int(&args[0], &option)) 235 return -EINVAL; 236 uid = make_kuid(current_user_ns(), option); 237 if (!uid_valid(uid)) 238 return -EINVAL; 239 hypfs_info->uid = uid; 240 break; 241 case opt_gid: 242 if (match_int(&args[0], &option)) 243 return -EINVAL; 244 gid = make_kgid(current_user_ns(), option); 245 if (!gid_valid(gid)) 246 return -EINVAL; 247 hypfs_info->gid = gid; 248 break; 249 case opt_err: 250 default: 251 pr_err("%s is not a valid mount option\n", str); 252 return -EINVAL; 253 } 254 } 255 return 0; 256 } 257 258 static int hypfs_show_options(struct seq_file *s, struct dentry *root) 259 { 260 struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info; 261 262 seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid)); 263 seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid)); 264 return 0; 265 } 266 267 static int hypfs_fill_super(struct super_block *sb, void *data, int silent) 268 { 269 struct inode *root_inode; 270 struct dentry *root_dentry; 271 int rc = 0; 272 struct hypfs_sb_info *sbi; 273 274 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); 275 if (!sbi) 276 return -ENOMEM; 277 mutex_init(&sbi->lock); 278 sbi->uid = current_uid(); 279 sbi->gid = current_gid(); 280 sb->s_fs_info = sbi; 281 sb->s_blocksize = PAGE_CACHE_SIZE; 282 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 283 sb->s_magic = HYPFS_MAGIC; 284 sb->s_op = &hypfs_s_ops; 285 if (hypfs_parse_options(data, sb)) 286 return -EINVAL; 287 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755); 288 if (!root_inode) 289 return -ENOMEM; 290 root_inode->i_op = &simple_dir_inode_operations; 291 root_inode->i_fop = &simple_dir_operations; 292 sb->s_root = root_dentry = d_make_root(root_inode); 293 if (!root_dentry) 294 return -ENOMEM; 295 if (MACHINE_IS_VM) 296 rc = hypfs_vm_create_files(root_dentry); 297 else 298 rc = hypfs_diag_create_files(root_dentry); 299 if (rc) 300 return rc; 301 sbi->update_file = hypfs_create_update_file(root_dentry); 302 if (IS_ERR(sbi->update_file)) 303 return PTR_ERR(sbi->update_file); 304 hypfs_update_update(sb); 305 pr_info("Hypervisor filesystem mounted\n"); 306 return 0; 307 } 308 309 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags, 310 const char *devname, void *data) 311 { 312 return mount_single(fst, flags, data, hypfs_fill_super); 313 } 314 315 static void hypfs_kill_super(struct super_block *sb) 316 { 317 struct hypfs_sb_info *sb_info = sb->s_fs_info; 318 319 if (sb->s_root) 320 hypfs_delete_tree(sb->s_root); 321 if (sb_info->update_file) 322 hypfs_remove(sb_info->update_file); 323 kfree(sb->s_fs_info); 324 sb->s_fs_info = NULL; 325 kill_litter_super(sb); 326 } 327 328 static struct dentry *hypfs_create_file(struct dentry *parent, const char *name, 329 char *data, umode_t mode) 330 { 331 struct dentry *dentry; 332 struct inode *inode; 333 334 mutex_lock(&d_inode(parent)->i_mutex); 335 dentry = lookup_one_len(name, parent, strlen(name)); 336 if (IS_ERR(dentry)) { 337 dentry = ERR_PTR(-ENOMEM); 338 goto fail; 339 } 340 inode = hypfs_make_inode(parent->d_sb, mode); 341 if (!inode) { 342 dput(dentry); 343 dentry = ERR_PTR(-ENOMEM); 344 goto fail; 345 } 346 if (S_ISREG(mode)) { 347 inode->i_fop = &hypfs_file_ops; 348 if (data) 349 inode->i_size = strlen(data); 350 else 351 inode->i_size = 0; 352 } else if (S_ISDIR(mode)) { 353 inode->i_op = &simple_dir_inode_operations; 354 inode->i_fop = &simple_dir_operations; 355 inc_nlink(d_inode(parent)); 356 } else 357 BUG(); 358 inode->i_private = data; 359 d_instantiate(dentry, inode); 360 dget(dentry); 361 fail: 362 mutex_unlock(&d_inode(parent)->i_mutex); 363 return dentry; 364 } 365 366 struct dentry *hypfs_mkdir(struct dentry *parent, const char *name) 367 { 368 struct dentry *dentry; 369 370 dentry = hypfs_create_file(parent, name, NULL, S_IFDIR | DIR_MODE); 371 if (IS_ERR(dentry)) 372 return dentry; 373 hypfs_add_dentry(dentry); 374 return dentry; 375 } 376 377 static struct dentry *hypfs_create_update_file(struct dentry *dir) 378 { 379 struct dentry *dentry; 380 381 dentry = hypfs_create_file(dir, "update", NULL, 382 S_IFREG | UPDATE_FILE_MODE); 383 /* 384 * We do not put the update file on the 'delete' list with 385 * hypfs_add_dentry(), since it should not be removed when the tree 386 * is updated. 387 */ 388 return dentry; 389 } 390 391 struct dentry *hypfs_create_u64(struct dentry *dir, 392 const char *name, __u64 value) 393 { 394 char *buffer; 395 char tmp[TMP_SIZE]; 396 struct dentry *dentry; 397 398 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value); 399 buffer = kstrdup(tmp, GFP_KERNEL); 400 if (!buffer) 401 return ERR_PTR(-ENOMEM); 402 dentry = 403 hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE); 404 if (IS_ERR(dentry)) { 405 kfree(buffer); 406 return ERR_PTR(-ENOMEM); 407 } 408 hypfs_add_dentry(dentry); 409 return dentry; 410 } 411 412 struct dentry *hypfs_create_str(struct dentry *dir, 413 const char *name, char *string) 414 { 415 char *buffer; 416 struct dentry *dentry; 417 418 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); 419 if (!buffer) 420 return ERR_PTR(-ENOMEM); 421 sprintf(buffer, "%s\n", string); 422 dentry = 423 hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE); 424 if (IS_ERR(dentry)) { 425 kfree(buffer); 426 return ERR_PTR(-ENOMEM); 427 } 428 hypfs_add_dentry(dentry); 429 return dentry; 430 } 431 432 static const struct file_operations hypfs_file_ops = { 433 .open = hypfs_open, 434 .release = hypfs_release, 435 .read_iter = hypfs_read_iter, 436 .write_iter = hypfs_write_iter, 437 .llseek = no_llseek, 438 }; 439 440 static struct file_system_type hypfs_type = { 441 .owner = THIS_MODULE, 442 .name = "s390_hypfs", 443 .mount = hypfs_mount, 444 .kill_sb = hypfs_kill_super 445 }; 446 MODULE_ALIAS_FS("s390_hypfs"); 447 448 static const struct super_operations hypfs_s_ops = { 449 .statfs = simple_statfs, 450 .evict_inode = hypfs_evict_inode, 451 .show_options = hypfs_show_options, 452 }; 453 454 static int __init hypfs_init(void) 455 { 456 int rc; 457 458 rc = hypfs_dbfs_init(); 459 if (rc) 460 return rc; 461 if (hypfs_diag_init()) { 462 rc = -ENODATA; 463 goto fail_dbfs_exit; 464 } 465 if (hypfs_vm_init()) { 466 rc = -ENODATA; 467 goto fail_hypfs_diag_exit; 468 } 469 if (hypfs_sprp_init()) { 470 rc = -ENODATA; 471 goto fail_hypfs_vm_exit; 472 } 473 if (hypfs_diag0c_init()) { 474 rc = -ENODATA; 475 goto fail_hypfs_sprp_exit; 476 } 477 rc = sysfs_create_mount_point(hypervisor_kobj, "s390"); 478 if (rc) 479 goto fail_hypfs_diag0c_exit; 480 rc = register_filesystem(&hypfs_type); 481 if (rc) 482 goto fail_filesystem; 483 return 0; 484 485 fail_filesystem: 486 sysfs_remove_mount_point(hypervisor_kobj, "s390"); 487 fail_hypfs_diag0c_exit: 488 hypfs_diag0c_exit(); 489 fail_hypfs_sprp_exit: 490 hypfs_sprp_exit(); 491 fail_hypfs_vm_exit: 492 hypfs_vm_exit(); 493 fail_hypfs_diag_exit: 494 hypfs_diag_exit(); 495 fail_dbfs_exit: 496 hypfs_dbfs_exit(); 497 pr_err("Initialization of hypfs failed with rc=%i\n", rc); 498 return rc; 499 } 500 501 static void __exit hypfs_exit(void) 502 { 503 unregister_filesystem(&hypfs_type); 504 sysfs_remove_mount_point(hypervisor_kobj, "s390"); 505 hypfs_diag0c_exit(); 506 hypfs_sprp_exit(); 507 hypfs_vm_exit(); 508 hypfs_diag_exit(); 509 hypfs_dbfs_exit(); 510 } 511 512 module_init(hypfs_init) 513 module_exit(hypfs_exit) 514 515 MODULE_LICENSE("GPL"); 516 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>"); 517 MODULE_DESCRIPTION("s390 Hypervisor Filesystem"); 518