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 = 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_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 = file_inode(iocb->ki_filp)->i_sb; 175 struct hypfs_sb_info *fs_info = sb->s_fs_info; 176 size_t count = iov_length(iov, nr_segs); 177 178 /* 179 * Currently we only allow one update per second for two reasons: 180 * 1. diag 204 is VERY expensive 181 * 2. If several processes do updates in parallel and then read the 182 * hypfs data, the likelihood of collisions is reduced, if we restrict 183 * the minimum update interval. A collision occurs, if during the 184 * data gathering of one process another process triggers an update 185 * If the first process wants to ensure consistent data, it has 186 * to restart data collection in this case. 187 */ 188 mutex_lock(&fs_info->lock); 189 if (fs_info->last_update == get_seconds()) { 190 rc = -EBUSY; 191 goto out; 192 } 193 hypfs_delete_tree(sb->s_root); 194 if (MACHINE_IS_VM) 195 rc = hypfs_vm_create_files(sb, sb->s_root); 196 else 197 rc = hypfs_diag_create_files(sb, sb->s_root); 198 if (rc) { 199 pr_err("Updating the hypfs tree failed\n"); 200 hypfs_delete_tree(sb->s_root); 201 goto out; 202 } 203 hypfs_update_update(sb); 204 rc = count; 205 out: 206 mutex_unlock(&fs_info->lock); 207 return rc; 208 } 209 210 static int hypfs_release(struct inode *inode, struct file *filp) 211 { 212 kfree(filp->private_data); 213 return 0; 214 } 215 216 enum { opt_uid, opt_gid, opt_err }; 217 218 static const match_table_t hypfs_tokens = { 219 {opt_uid, "uid=%u"}, 220 {opt_gid, "gid=%u"}, 221 {opt_err, NULL} 222 }; 223 224 static int hypfs_parse_options(char *options, struct super_block *sb) 225 { 226 char *str; 227 substring_t args[MAX_OPT_ARGS]; 228 kuid_t uid; 229 kgid_t gid; 230 231 if (!options) 232 return 0; 233 while ((str = strsep(&options, ",")) != NULL) { 234 int token, option; 235 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 236 237 if (!*str) 238 continue; 239 token = match_token(str, hypfs_tokens, args); 240 switch (token) { 241 case opt_uid: 242 if (match_int(&args[0], &option)) 243 return -EINVAL; 244 uid = make_kuid(current_user_ns(), option); 245 if (!uid_valid(uid)) 246 return -EINVAL; 247 hypfs_info->uid = uid; 248 break; 249 case opt_gid: 250 if (match_int(&args[0], &option)) 251 return -EINVAL; 252 gid = make_kgid(current_user_ns(), option); 253 if (!gid_valid(gid)) 254 return -EINVAL; 255 hypfs_info->gid = gid; 256 break; 257 case opt_err: 258 default: 259 pr_err("%s is not a valid mount option\n", str); 260 return -EINVAL; 261 } 262 } 263 return 0; 264 } 265 266 static int hypfs_show_options(struct seq_file *s, struct dentry *root) 267 { 268 struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info; 269 270 seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid)); 271 seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid)); 272 return 0; 273 } 274 275 static int hypfs_fill_super(struct super_block *sb, void *data, int silent) 276 { 277 struct inode *root_inode; 278 struct dentry *root_dentry; 279 int rc = 0; 280 struct hypfs_sb_info *sbi; 281 282 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); 283 if (!sbi) 284 return -ENOMEM; 285 mutex_init(&sbi->lock); 286 sbi->uid = current_uid(); 287 sbi->gid = current_gid(); 288 sb->s_fs_info = sbi; 289 sb->s_blocksize = PAGE_CACHE_SIZE; 290 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 291 sb->s_magic = HYPFS_MAGIC; 292 sb->s_op = &hypfs_s_ops; 293 if (hypfs_parse_options(data, sb)) 294 return -EINVAL; 295 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755); 296 if (!root_inode) 297 return -ENOMEM; 298 root_inode->i_op = &simple_dir_inode_operations; 299 root_inode->i_fop = &simple_dir_operations; 300 sb->s_root = root_dentry = d_make_root(root_inode); 301 if (!root_dentry) 302 return -ENOMEM; 303 if (MACHINE_IS_VM) 304 rc = hypfs_vm_create_files(sb, root_dentry); 305 else 306 rc = hypfs_diag_create_files(sb, root_dentry); 307 if (rc) 308 return rc; 309 sbi->update_file = hypfs_create_update_file(sb, root_dentry); 310 if (IS_ERR(sbi->update_file)) 311 return PTR_ERR(sbi->update_file); 312 hypfs_update_update(sb); 313 pr_info("Hypervisor filesystem mounted\n"); 314 return 0; 315 } 316 317 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags, 318 const char *devname, void *data) 319 { 320 return mount_single(fst, flags, data, hypfs_fill_super); 321 } 322 323 static void hypfs_kill_super(struct super_block *sb) 324 { 325 struct hypfs_sb_info *sb_info = sb->s_fs_info; 326 327 if (sb->s_root) 328 hypfs_delete_tree(sb->s_root); 329 if (sb_info->update_file) 330 hypfs_remove(sb_info->update_file); 331 kfree(sb->s_fs_info); 332 sb->s_fs_info = NULL; 333 kill_litter_super(sb); 334 } 335 336 static struct dentry *hypfs_create_file(struct super_block *sb, 337 struct dentry *parent, const char *name, 338 char *data, umode_t mode) 339 { 340 struct dentry *dentry; 341 struct inode *inode; 342 343 mutex_lock(&parent->d_inode->i_mutex); 344 dentry = lookup_one_len(name, parent, strlen(name)); 345 if (IS_ERR(dentry)) { 346 dentry = ERR_PTR(-ENOMEM); 347 goto fail; 348 } 349 inode = hypfs_make_inode(sb, mode); 350 if (!inode) { 351 dput(dentry); 352 dentry = ERR_PTR(-ENOMEM); 353 goto fail; 354 } 355 if (S_ISREG(mode)) { 356 inode->i_fop = &hypfs_file_ops; 357 if (data) 358 inode->i_size = strlen(data); 359 else 360 inode->i_size = 0; 361 } else if (S_ISDIR(mode)) { 362 inode->i_op = &simple_dir_inode_operations; 363 inode->i_fop = &simple_dir_operations; 364 inc_nlink(parent->d_inode); 365 } else 366 BUG(); 367 inode->i_private = data; 368 d_instantiate(dentry, inode); 369 dget(dentry); 370 fail: 371 mutex_unlock(&parent->d_inode->i_mutex); 372 return dentry; 373 } 374 375 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent, 376 const char *name) 377 { 378 struct dentry *dentry; 379 380 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE); 381 if (IS_ERR(dentry)) 382 return dentry; 383 hypfs_add_dentry(dentry); 384 return dentry; 385 } 386 387 static struct dentry *hypfs_create_update_file(struct super_block *sb, 388 struct dentry *dir) 389 { 390 struct dentry *dentry; 391 392 dentry = hypfs_create_file(sb, dir, "update", NULL, 393 S_IFREG | UPDATE_FILE_MODE); 394 /* 395 * We do not put the update file on the 'delete' list with 396 * hypfs_add_dentry(), since it should not be removed when the tree 397 * is updated. 398 */ 399 return dentry; 400 } 401 402 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir, 403 const char *name, __u64 value) 404 { 405 char *buffer; 406 char tmp[TMP_SIZE]; 407 struct dentry *dentry; 408 409 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value); 410 buffer = kstrdup(tmp, GFP_KERNEL); 411 if (!buffer) 412 return ERR_PTR(-ENOMEM); 413 dentry = 414 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 415 if (IS_ERR(dentry)) { 416 kfree(buffer); 417 return ERR_PTR(-ENOMEM); 418 } 419 hypfs_add_dentry(dentry); 420 return dentry; 421 } 422 423 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir, 424 const char *name, char *string) 425 { 426 char *buffer; 427 struct dentry *dentry; 428 429 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); 430 if (!buffer) 431 return ERR_PTR(-ENOMEM); 432 sprintf(buffer, "%s\n", string); 433 dentry = 434 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 435 if (IS_ERR(dentry)) { 436 kfree(buffer); 437 return ERR_PTR(-ENOMEM); 438 } 439 hypfs_add_dentry(dentry); 440 return dentry; 441 } 442 443 static const struct file_operations hypfs_file_ops = { 444 .open = hypfs_open, 445 .release = hypfs_release, 446 .read = do_sync_read, 447 .write = do_sync_write, 448 .aio_read = hypfs_aio_read, 449 .aio_write = hypfs_aio_write, 450 .llseek = no_llseek, 451 }; 452 453 static struct file_system_type hypfs_type = { 454 .owner = THIS_MODULE, 455 .name = "s390_hypfs", 456 .mount = hypfs_mount, 457 .kill_sb = hypfs_kill_super 458 }; 459 460 static const struct super_operations hypfs_s_ops = { 461 .statfs = simple_statfs, 462 .evict_inode = hypfs_evict_inode, 463 .show_options = hypfs_show_options, 464 }; 465 466 static struct kobject *s390_kobj; 467 468 static int __init hypfs_init(void) 469 { 470 int rc; 471 472 rc = hypfs_dbfs_init(); 473 if (rc) 474 return rc; 475 if (hypfs_diag_init()) { 476 rc = -ENODATA; 477 goto fail_dbfs_exit; 478 } 479 if (hypfs_vm_init()) { 480 rc = -ENODATA; 481 goto fail_hypfs_diag_exit; 482 } 483 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj); 484 if (!s390_kobj) { 485 rc = -ENOMEM; 486 goto fail_hypfs_vm_exit; 487 } 488 rc = register_filesystem(&hypfs_type); 489 if (rc) 490 goto fail_filesystem; 491 return 0; 492 493 fail_filesystem: 494 kobject_put(s390_kobj); 495 fail_hypfs_vm_exit: 496 hypfs_vm_exit(); 497 fail_hypfs_diag_exit: 498 hypfs_diag_exit(); 499 fail_dbfs_exit: 500 hypfs_dbfs_exit(); 501 pr_err("Initialization of hypfs failed with rc=%i\n", rc); 502 return rc; 503 } 504 505 static void __exit hypfs_exit(void) 506 { 507 hypfs_diag_exit(); 508 hypfs_vm_exit(); 509 hypfs_dbfs_exit(); 510 unregister_filesystem(&hypfs_type); 511 kobject_put(s390_kobj); 512 } 513 514 module_init(hypfs_init) 515 module_exit(hypfs_exit) 516 517 MODULE_LICENSE("GPL"); 518 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>"); 519 MODULE_DESCRIPTION("s390 Hypervisor Filesystem"); 520