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->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(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"); 522