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 mutex_lock(&parent->d_inode->i_mutex); 76 if (hypfs_positive(dentry)) { 77 if (S_ISDIR(dentry->d_inode->i_mode)) 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 = filp->f_path.dentry->d_inode->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_aio_read(struct kiocb *iocb, const struct iovec *iov, 148 unsigned long nr_segs, loff_t offset) 149 { 150 char *data; 151 ssize_t ret; 152 struct file *filp = iocb->ki_filp; 153 /* XXX: temporary */ 154 char __user *buf = iov[0].iov_base; 155 size_t count = iov[0].iov_len; 156 157 if (nr_segs != 1) 158 return -EINVAL; 159 160 data = filp->private_data; 161 ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data)); 162 if (ret <= 0) 163 return ret; 164 165 iocb->ki_pos += ret; 166 file_accessed(filp); 167 168 return ret; 169 } 170 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov, 171 unsigned long nr_segs, loff_t offset) 172 { 173 int rc; 174 struct super_block *sb; 175 struct hypfs_sb_info *fs_info; 176 size_t count = iov_length(iov, nr_segs); 177 178 sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb; 179 fs_info = sb->s_fs_info; 180 /* 181 * Currently we only allow one update per second for two reasons: 182 * 1. diag 204 is VERY expensive 183 * 2. If several processes do updates in parallel and then read the 184 * hypfs data, the likelihood of collisions is reduced, if we restrict 185 * the minimum update interval. A collision occurs, if during the 186 * data gathering of one process another process triggers an update 187 * If the first process wants to ensure consistent data, it has 188 * to restart data collection in this case. 189 */ 190 mutex_lock(&fs_info->lock); 191 if (fs_info->last_update == get_seconds()) { 192 rc = -EBUSY; 193 goto out; 194 } 195 hypfs_delete_tree(sb->s_root); 196 if (MACHINE_IS_VM) 197 rc = hypfs_vm_create_files(sb, sb->s_root); 198 else 199 rc = hypfs_diag_create_files(sb, sb->s_root); 200 if (rc) { 201 pr_err("Updating the hypfs tree failed\n"); 202 hypfs_delete_tree(sb->s_root); 203 goto out; 204 } 205 hypfs_update_update(sb); 206 rc = count; 207 out: 208 mutex_unlock(&fs_info->lock); 209 return rc; 210 } 211 212 static int hypfs_release(struct inode *inode, struct file *filp) 213 { 214 kfree(filp->private_data); 215 return 0; 216 } 217 218 enum { opt_uid, opt_gid, opt_err }; 219 220 static const match_table_t hypfs_tokens = { 221 {opt_uid, "uid=%u"}, 222 {opt_gid, "gid=%u"}, 223 {opt_err, NULL} 224 }; 225 226 static int hypfs_parse_options(char *options, struct super_block *sb) 227 { 228 char *str; 229 substring_t args[MAX_OPT_ARGS]; 230 kuid_t uid; 231 kgid_t gid; 232 233 if (!options) 234 return 0; 235 while ((str = strsep(&options, ",")) != NULL) { 236 int token, option; 237 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 238 239 if (!*str) 240 continue; 241 token = match_token(str, hypfs_tokens, args); 242 switch (token) { 243 case opt_uid: 244 if (match_int(&args[0], &option)) 245 return -EINVAL; 246 uid = make_kuid(current_user_ns(), option); 247 if (!uid_valid(uid)) 248 return -EINVAL; 249 hypfs_info->uid = uid; 250 break; 251 case opt_gid: 252 if (match_int(&args[0], &option)) 253 return -EINVAL; 254 gid = make_kgid(current_user_ns(), option); 255 if (!gid_valid(gid)) 256 return -EINVAL; 257 hypfs_info->gid = gid; 258 break; 259 case opt_err: 260 default: 261 pr_err("%s is not a valid mount option\n", str); 262 return -EINVAL; 263 } 264 } 265 return 0; 266 } 267 268 static int hypfs_show_options(struct seq_file *s, struct dentry *root) 269 { 270 struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info; 271 272 seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid)); 273 seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid)); 274 return 0; 275 } 276 277 static int hypfs_fill_super(struct super_block *sb, void *data, int silent) 278 { 279 struct inode *root_inode; 280 struct dentry *root_dentry; 281 int rc = 0; 282 struct hypfs_sb_info *sbi; 283 284 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); 285 if (!sbi) 286 return -ENOMEM; 287 mutex_init(&sbi->lock); 288 sbi->uid = current_uid(); 289 sbi->gid = current_gid(); 290 sb->s_fs_info = sbi; 291 sb->s_blocksize = PAGE_CACHE_SIZE; 292 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 293 sb->s_magic = HYPFS_MAGIC; 294 sb->s_op = &hypfs_s_ops; 295 if (hypfs_parse_options(data, sb)) 296 return -EINVAL; 297 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755); 298 if (!root_inode) 299 return -ENOMEM; 300 root_inode->i_op = &simple_dir_inode_operations; 301 root_inode->i_fop = &simple_dir_operations; 302 sb->s_root = root_dentry = d_make_root(root_inode); 303 if (!root_dentry) 304 return -ENOMEM; 305 if (MACHINE_IS_VM) 306 rc = hypfs_vm_create_files(sb, root_dentry); 307 else 308 rc = hypfs_diag_create_files(sb, root_dentry); 309 if (rc) 310 return rc; 311 sbi->update_file = hypfs_create_update_file(sb, root_dentry); 312 if (IS_ERR(sbi->update_file)) 313 return PTR_ERR(sbi->update_file); 314 hypfs_update_update(sb); 315 pr_info("Hypervisor filesystem mounted\n"); 316 return 0; 317 } 318 319 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags, 320 const char *devname, void *data) 321 { 322 return mount_single(fst, flags, data, hypfs_fill_super); 323 } 324 325 static void hypfs_kill_super(struct super_block *sb) 326 { 327 struct hypfs_sb_info *sb_info = sb->s_fs_info; 328 329 if (sb->s_root) 330 hypfs_delete_tree(sb->s_root); 331 if (sb_info->update_file) 332 hypfs_remove(sb_info->update_file); 333 kfree(sb->s_fs_info); 334 sb->s_fs_info = NULL; 335 kill_litter_super(sb); 336 } 337 338 static struct dentry *hypfs_create_file(struct super_block *sb, 339 struct dentry *parent, const char *name, 340 char *data, umode_t mode) 341 { 342 struct dentry *dentry; 343 struct inode *inode; 344 345 mutex_lock(&parent->d_inode->i_mutex); 346 dentry = lookup_one_len(name, parent, strlen(name)); 347 if (IS_ERR(dentry)) { 348 dentry = ERR_PTR(-ENOMEM); 349 goto fail; 350 } 351 inode = hypfs_make_inode(sb, mode); 352 if (!inode) { 353 dput(dentry); 354 dentry = ERR_PTR(-ENOMEM); 355 goto fail; 356 } 357 if (S_ISREG(mode)) { 358 inode->i_fop = &hypfs_file_ops; 359 if (data) 360 inode->i_size = strlen(data); 361 else 362 inode->i_size = 0; 363 } else if (S_ISDIR(mode)) { 364 inode->i_op = &simple_dir_inode_operations; 365 inode->i_fop = &simple_dir_operations; 366 inc_nlink(parent->d_inode); 367 } else 368 BUG(); 369 inode->i_private = data; 370 d_instantiate(dentry, inode); 371 dget(dentry); 372 fail: 373 mutex_unlock(&parent->d_inode->i_mutex); 374 return dentry; 375 } 376 377 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent, 378 const char *name) 379 { 380 struct dentry *dentry; 381 382 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE); 383 if (IS_ERR(dentry)) 384 return dentry; 385 hypfs_add_dentry(dentry); 386 return dentry; 387 } 388 389 static struct dentry *hypfs_create_update_file(struct super_block *sb, 390 struct dentry *dir) 391 { 392 struct dentry *dentry; 393 394 dentry = hypfs_create_file(sb, dir, "update", NULL, 395 S_IFREG | UPDATE_FILE_MODE); 396 /* 397 * We do not put the update file on the 'delete' list with 398 * hypfs_add_dentry(), since it should not be removed when the tree 399 * is updated. 400 */ 401 return dentry; 402 } 403 404 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir, 405 const char *name, __u64 value) 406 { 407 char *buffer; 408 char tmp[TMP_SIZE]; 409 struct dentry *dentry; 410 411 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value); 412 buffer = kstrdup(tmp, GFP_KERNEL); 413 if (!buffer) 414 return ERR_PTR(-ENOMEM); 415 dentry = 416 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 417 if (IS_ERR(dentry)) { 418 kfree(buffer); 419 return ERR_PTR(-ENOMEM); 420 } 421 hypfs_add_dentry(dentry); 422 return dentry; 423 } 424 425 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir, 426 const char *name, char *string) 427 { 428 char *buffer; 429 struct dentry *dentry; 430 431 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); 432 if (!buffer) 433 return ERR_PTR(-ENOMEM); 434 sprintf(buffer, "%s\n", string); 435 dentry = 436 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 437 if (IS_ERR(dentry)) { 438 kfree(buffer); 439 return ERR_PTR(-ENOMEM); 440 } 441 hypfs_add_dentry(dentry); 442 return dentry; 443 } 444 445 static const struct file_operations hypfs_file_ops = { 446 .open = hypfs_open, 447 .release = hypfs_release, 448 .read = do_sync_read, 449 .write = do_sync_write, 450 .aio_read = hypfs_aio_read, 451 .aio_write = hypfs_aio_write, 452 .llseek = no_llseek, 453 }; 454 455 static struct file_system_type hypfs_type = { 456 .owner = THIS_MODULE, 457 .name = "s390_hypfs", 458 .mount = hypfs_mount, 459 .kill_sb = hypfs_kill_super 460 }; 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