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 uid_t uid; /* uid used for files and dirs */ 35 gid_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 if (!parent || !parent->d_inode) 76 return; 77 mutex_lock(&parent->d_inode->i_mutex); 78 if (hypfs_positive(dentry)) { 79 if (S_ISDIR(dentry->d_inode->i_mode)) 80 simple_rmdir(parent->d_inode, dentry); 81 else 82 simple_unlink(parent->d_inode, dentry); 83 } 84 d_delete(dentry); 85 dput(dentry); 86 mutex_unlock(&parent->d_inode->i_mutex); 87 } 88 89 static void hypfs_delete_tree(struct dentry *root) 90 { 91 while (hypfs_last_dentry) { 92 struct dentry *next_dentry; 93 next_dentry = hypfs_last_dentry->d_fsdata; 94 hypfs_remove(hypfs_last_dentry); 95 hypfs_last_dentry = next_dentry; 96 } 97 } 98 99 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode) 100 { 101 struct inode *ret = new_inode(sb); 102 103 if (ret) { 104 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 105 ret->i_ino = get_next_ino(); 106 ret->i_mode = mode; 107 ret->i_uid = hypfs_info->uid; 108 ret->i_gid = hypfs_info->gid; 109 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME; 110 if (S_ISDIR(mode)) 111 set_nlink(ret, 2); 112 } 113 return ret; 114 } 115 116 static void hypfs_evict_inode(struct inode *inode) 117 { 118 clear_inode(inode); 119 kfree(inode->i_private); 120 } 121 122 static int hypfs_open(struct inode *inode, struct file *filp) 123 { 124 char *data = filp->f_path.dentry->d_inode->i_private; 125 struct hypfs_sb_info *fs_info; 126 127 if (filp->f_mode & FMODE_WRITE) { 128 if (!(inode->i_mode & S_IWUGO)) 129 return -EACCES; 130 } 131 if (filp->f_mode & FMODE_READ) { 132 if (!(inode->i_mode & S_IRUGO)) 133 return -EACCES; 134 } 135 136 fs_info = inode->i_sb->s_fs_info; 137 if(data) { 138 mutex_lock(&fs_info->lock); 139 filp->private_data = kstrdup(data, GFP_KERNEL); 140 if (!filp->private_data) { 141 mutex_unlock(&fs_info->lock); 142 return -ENOMEM; 143 } 144 mutex_unlock(&fs_info->lock); 145 } 146 return nonseekable_open(inode, filp); 147 } 148 149 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov, 150 unsigned long nr_segs, loff_t offset) 151 { 152 char *data; 153 ssize_t ret; 154 struct file *filp = iocb->ki_filp; 155 /* XXX: temporary */ 156 char __user *buf = iov[0].iov_base; 157 size_t count = iov[0].iov_len; 158 159 if (nr_segs != 1) 160 return -EINVAL; 161 162 data = filp->private_data; 163 ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data)); 164 if (ret <= 0) 165 return ret; 166 167 iocb->ki_pos += ret; 168 file_accessed(filp); 169 170 return ret; 171 } 172 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov, 173 unsigned long nr_segs, loff_t offset) 174 { 175 int rc; 176 struct super_block *sb; 177 struct hypfs_sb_info *fs_info; 178 size_t count = iov_length(iov, nr_segs); 179 180 sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb; 181 fs_info = sb->s_fs_info; 182 /* 183 * Currently we only allow one update per second for two reasons: 184 * 1. diag 204 is VERY expensive 185 * 2. If several processes do updates in parallel and then read the 186 * hypfs data, the likelihood of collisions is reduced, if we restrict 187 * the minimum update interval. A collision occurs, if during the 188 * data gathering of one process another process triggers an update 189 * If the first process wants to ensure consistent data, it has 190 * to restart data collection in this case. 191 */ 192 mutex_lock(&fs_info->lock); 193 if (fs_info->last_update == get_seconds()) { 194 rc = -EBUSY; 195 goto out; 196 } 197 hypfs_delete_tree(sb->s_root); 198 if (MACHINE_IS_VM) 199 rc = hypfs_vm_create_files(sb, sb->s_root); 200 else 201 rc = hypfs_diag_create_files(sb, sb->s_root); 202 if (rc) { 203 pr_err("Updating the hypfs tree failed\n"); 204 hypfs_delete_tree(sb->s_root); 205 goto out; 206 } 207 hypfs_update_update(sb); 208 rc = count; 209 out: 210 mutex_unlock(&fs_info->lock); 211 return rc; 212 } 213 214 static int hypfs_release(struct inode *inode, struct file *filp) 215 { 216 kfree(filp->private_data); 217 return 0; 218 } 219 220 enum { opt_uid, opt_gid, opt_err }; 221 222 static const match_table_t hypfs_tokens = { 223 {opt_uid, "uid=%u"}, 224 {opt_gid, "gid=%u"}, 225 {opt_err, NULL} 226 }; 227 228 static int hypfs_parse_options(char *options, struct super_block *sb) 229 { 230 char *str; 231 substring_t args[MAX_OPT_ARGS]; 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 hypfs_info->uid = option; 247 break; 248 case opt_gid: 249 if (match_int(&args[0], &option)) 250 return -EINVAL; 251 hypfs_info->gid = option; 252 break; 253 case opt_err: 254 default: 255 pr_err("%s is not a valid mount option\n", str); 256 return -EINVAL; 257 } 258 } 259 return 0; 260 } 261 262 static int hypfs_show_options(struct seq_file *s, struct dentry *root) 263 { 264 struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info; 265 266 seq_printf(s, ",uid=%u", hypfs_info->uid); 267 seq_printf(s, ",gid=%u", hypfs_info->gid); 268 return 0; 269 } 270 271 static int hypfs_fill_super(struct super_block *sb, void *data, int silent) 272 { 273 struct inode *root_inode; 274 struct dentry *root_dentry; 275 int rc = 0; 276 struct hypfs_sb_info *sbi; 277 278 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); 279 if (!sbi) 280 return -ENOMEM; 281 mutex_init(&sbi->lock); 282 sbi->uid = current_uid(); 283 sbi->gid = current_gid(); 284 sb->s_fs_info = sbi; 285 sb->s_blocksize = PAGE_CACHE_SIZE; 286 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 287 sb->s_magic = HYPFS_MAGIC; 288 sb->s_op = &hypfs_s_ops; 289 if (hypfs_parse_options(data, sb)) 290 return -EINVAL; 291 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755); 292 if (!root_inode) 293 return -ENOMEM; 294 root_inode->i_op = &simple_dir_inode_operations; 295 root_inode->i_fop = &simple_dir_operations; 296 sb->s_root = root_dentry = d_make_root(root_inode); 297 if (!root_dentry) 298 return -ENOMEM; 299 if (MACHINE_IS_VM) 300 rc = hypfs_vm_create_files(sb, root_dentry); 301 else 302 rc = hypfs_diag_create_files(sb, root_dentry); 303 if (rc) 304 return rc; 305 sbi->update_file = hypfs_create_update_file(sb, root_dentry); 306 if (IS_ERR(sbi->update_file)) 307 return PTR_ERR(sbi->update_file); 308 hypfs_update_update(sb); 309 pr_info("Hypervisor filesystem mounted\n"); 310 return 0; 311 } 312 313 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags, 314 const char *devname, void *data) 315 { 316 return mount_single(fst, flags, data, hypfs_fill_super); 317 } 318 319 static void hypfs_kill_super(struct super_block *sb) 320 { 321 struct hypfs_sb_info *sb_info = sb->s_fs_info; 322 323 if (sb->s_root) 324 hypfs_delete_tree(sb->s_root); 325 if (sb_info->update_file) 326 hypfs_remove(sb_info->update_file); 327 kfree(sb->s_fs_info); 328 sb->s_fs_info = NULL; 329 kill_litter_super(sb); 330 } 331 332 static struct dentry *hypfs_create_file(struct super_block *sb, 333 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(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 super_block *sb, struct dentry *parent, 372 const char *name) 373 { 374 struct dentry *dentry; 375 376 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE); 377 if (IS_ERR(dentry)) 378 return dentry; 379 hypfs_add_dentry(dentry); 380 return dentry; 381 } 382 383 static struct dentry *hypfs_create_update_file(struct super_block *sb, 384 struct dentry *dir) 385 { 386 struct dentry *dentry; 387 388 dentry = hypfs_create_file(sb, dir, "update", NULL, 389 S_IFREG | UPDATE_FILE_MODE); 390 /* 391 * We do not put the update file on the 'delete' list with 392 * hypfs_add_dentry(), since it should not be removed when the tree 393 * is updated. 394 */ 395 return dentry; 396 } 397 398 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir, 399 const char *name, __u64 value) 400 { 401 char *buffer; 402 char tmp[TMP_SIZE]; 403 struct dentry *dentry; 404 405 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value); 406 buffer = kstrdup(tmp, GFP_KERNEL); 407 if (!buffer) 408 return ERR_PTR(-ENOMEM); 409 dentry = 410 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 411 if (IS_ERR(dentry)) { 412 kfree(buffer); 413 return ERR_PTR(-ENOMEM); 414 } 415 hypfs_add_dentry(dentry); 416 return dentry; 417 } 418 419 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir, 420 const char *name, char *string) 421 { 422 char *buffer; 423 struct dentry *dentry; 424 425 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); 426 if (!buffer) 427 return ERR_PTR(-ENOMEM); 428 sprintf(buffer, "%s\n", string); 429 dentry = 430 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 431 if (IS_ERR(dentry)) { 432 kfree(buffer); 433 return ERR_PTR(-ENOMEM); 434 } 435 hypfs_add_dentry(dentry); 436 return dentry; 437 } 438 439 static const struct file_operations hypfs_file_ops = { 440 .open = hypfs_open, 441 .release = hypfs_release, 442 .read = do_sync_read, 443 .write = do_sync_write, 444 .aio_read = hypfs_aio_read, 445 .aio_write = hypfs_aio_write, 446 .llseek = no_llseek, 447 }; 448 449 static struct file_system_type hypfs_type = { 450 .owner = THIS_MODULE, 451 .name = "s390_hypfs", 452 .mount = hypfs_mount, 453 .kill_sb = hypfs_kill_super 454 }; 455 456 static const struct super_operations hypfs_s_ops = { 457 .statfs = simple_statfs, 458 .evict_inode = hypfs_evict_inode, 459 .show_options = hypfs_show_options, 460 }; 461 462 static struct kobject *s390_kobj; 463 464 static int __init hypfs_init(void) 465 { 466 int rc; 467 468 rc = hypfs_dbfs_init(); 469 if (rc) 470 return rc; 471 if (hypfs_diag_init()) { 472 rc = -ENODATA; 473 goto fail_dbfs_exit; 474 } 475 if (hypfs_vm_init()) { 476 rc = -ENODATA; 477 goto fail_hypfs_diag_exit; 478 } 479 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj); 480 if (!s390_kobj) { 481 rc = -ENOMEM; 482 goto fail_hypfs_vm_exit; 483 } 484 rc = register_filesystem(&hypfs_type); 485 if (rc) 486 goto fail_filesystem; 487 return 0; 488 489 fail_filesystem: 490 kobject_put(s390_kobj); 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 hypfs_diag_exit(); 504 hypfs_vm_exit(); 505 hypfs_dbfs_exit(); 506 unregister_filesystem(&hypfs_type); 507 kobject_put(s390_kobj); 508 } 509 510 module_init(hypfs_init) 511 module_exit(hypfs_exit) 512 513 MODULE_LICENSE("GPL"); 514 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>"); 515 MODULE_DESCRIPTION("s390 Hypervisor Filesystem"); 516