1 /* 2 * arch/s390/hypfs/inode.c 3 * Hypervisor filesystem for Linux on s390. 4 * 5 * Copyright IBM Corp. 2006, 2008 6 * Author(s): Michael Holzheu <holzheu@de.ibm.com> 7 */ 8 9 #define KMSG_COMPONENT "hypfs" 10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 11 12 #include <linux/types.h> 13 #include <linux/errno.h> 14 #include <linux/fs.h> 15 #include <linux/namei.h> 16 #include <linux/vfs.h> 17 #include <linux/slab.h> 18 #include <linux/pagemap.h> 19 #include <linux/time.h> 20 #include <linux/parser.h> 21 #include <linux/sysfs.h> 22 #include <linux/module.h> 23 #include <linux/seq_file.h> 24 #include <linux/mount.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 uid_t uid; /* uid used for files and dirs */ 36 gid_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 if (!parent || !parent->d_inode) 77 return; 78 mutex_lock(&parent->d_inode->i_mutex); 79 if (hypfs_positive(dentry)) { 80 if (S_ISDIR(dentry->d_inode->i_mode)) 81 simple_rmdir(parent->d_inode, dentry); 82 else 83 simple_unlink(parent->d_inode, dentry); 84 } 85 d_delete(dentry); 86 dput(dentry); 87 mutex_unlock(&parent->d_inode->i_mutex); 88 } 89 90 static void hypfs_delete_tree(struct dentry *root) 91 { 92 while (hypfs_last_dentry) { 93 struct dentry *next_dentry; 94 next_dentry = hypfs_last_dentry->d_fsdata; 95 hypfs_remove(hypfs_last_dentry); 96 hypfs_last_dentry = next_dentry; 97 } 98 } 99 100 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode) 101 { 102 struct inode *ret = new_inode(sb); 103 104 if (ret) { 105 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 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 end_writeback(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_alloc_root(root_inode); 297 if (!root_dentry) { 298 iput(root_inode); 299 return -ENOMEM; 300 } 301 if (MACHINE_IS_VM) 302 rc = hypfs_vm_create_files(sb, root_dentry); 303 else 304 rc = hypfs_diag_create_files(sb, root_dentry); 305 if (rc) 306 return rc; 307 sbi->update_file = hypfs_create_update_file(sb, root_dentry); 308 if (IS_ERR(sbi->update_file)) 309 return PTR_ERR(sbi->update_file); 310 hypfs_update_update(sb); 311 pr_info("Hypervisor filesystem mounted\n"); 312 return 0; 313 } 314 315 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags, 316 const char *devname, void *data) 317 { 318 return mount_single(fst, flags, data, hypfs_fill_super); 319 } 320 321 static void hypfs_kill_super(struct super_block *sb) 322 { 323 struct hypfs_sb_info *sb_info = sb->s_fs_info; 324 325 if (sb->s_root) 326 hypfs_delete_tree(sb->s_root); 327 if (sb_info->update_file) 328 hypfs_remove(sb_info->update_file); 329 kfree(sb->s_fs_info); 330 sb->s_fs_info = NULL; 331 kill_litter_super(sb); 332 } 333 334 static struct dentry *hypfs_create_file(struct super_block *sb, 335 struct dentry *parent, const char *name, 336 char *data, umode_t mode) 337 { 338 struct dentry *dentry; 339 struct inode *inode; 340 341 mutex_lock(&parent->d_inode->i_mutex); 342 dentry = lookup_one_len(name, parent, strlen(name)); 343 if (IS_ERR(dentry)) { 344 dentry = ERR_PTR(-ENOMEM); 345 goto fail; 346 } 347 inode = hypfs_make_inode(sb, mode); 348 if (!inode) { 349 dput(dentry); 350 dentry = ERR_PTR(-ENOMEM); 351 goto fail; 352 } 353 if (S_ISREG(mode)) { 354 inode->i_fop = &hypfs_file_ops; 355 if (data) 356 inode->i_size = strlen(data); 357 else 358 inode->i_size = 0; 359 } else if (S_ISDIR(mode)) { 360 inode->i_op = &simple_dir_inode_operations; 361 inode->i_fop = &simple_dir_operations; 362 inc_nlink(parent->d_inode); 363 } else 364 BUG(); 365 inode->i_private = data; 366 d_instantiate(dentry, inode); 367 dget(dentry); 368 fail: 369 mutex_unlock(&parent->d_inode->i_mutex); 370 return dentry; 371 } 372 373 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent, 374 const char *name) 375 { 376 struct dentry *dentry; 377 378 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE); 379 if (IS_ERR(dentry)) 380 return dentry; 381 hypfs_add_dentry(dentry); 382 return dentry; 383 } 384 385 static struct dentry *hypfs_create_update_file(struct super_block *sb, 386 struct dentry *dir) 387 { 388 struct dentry *dentry; 389 390 dentry = hypfs_create_file(sb, dir, "update", NULL, 391 S_IFREG | UPDATE_FILE_MODE); 392 /* 393 * We do not put the update file on the 'delete' list with 394 * hypfs_add_dentry(), since it should not be removed when the tree 395 * is updated. 396 */ 397 return dentry; 398 } 399 400 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir, 401 const char *name, __u64 value) 402 { 403 char *buffer; 404 char tmp[TMP_SIZE]; 405 struct dentry *dentry; 406 407 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value); 408 buffer = kstrdup(tmp, GFP_KERNEL); 409 if (!buffer) 410 return ERR_PTR(-ENOMEM); 411 dentry = 412 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 413 if (IS_ERR(dentry)) { 414 kfree(buffer); 415 return ERR_PTR(-ENOMEM); 416 } 417 hypfs_add_dentry(dentry); 418 return dentry; 419 } 420 421 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir, 422 const char *name, char *string) 423 { 424 char *buffer; 425 struct dentry *dentry; 426 427 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); 428 if (!buffer) 429 return ERR_PTR(-ENOMEM); 430 sprintf(buffer, "%s\n", string); 431 dentry = 432 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 433 if (IS_ERR(dentry)) { 434 kfree(buffer); 435 return ERR_PTR(-ENOMEM); 436 } 437 hypfs_add_dentry(dentry); 438 return dentry; 439 } 440 441 static const struct file_operations hypfs_file_ops = { 442 .open = hypfs_open, 443 .release = hypfs_release, 444 .read = do_sync_read, 445 .write = do_sync_write, 446 .aio_read = hypfs_aio_read, 447 .aio_write = hypfs_aio_write, 448 .llseek = no_llseek, 449 }; 450 451 static struct file_system_type hypfs_type = { 452 .owner = THIS_MODULE, 453 .name = "s390_hypfs", 454 .mount = hypfs_mount, 455 .kill_sb = hypfs_kill_super 456 }; 457 458 static const struct super_operations hypfs_s_ops = { 459 .statfs = simple_statfs, 460 .evict_inode = hypfs_evict_inode, 461 .show_options = hypfs_show_options, 462 }; 463 464 static struct kobject *s390_kobj; 465 466 static int __init hypfs_init(void) 467 { 468 int rc; 469 470 rc = hypfs_dbfs_init(); 471 if (rc) 472 return rc; 473 if (hypfs_diag_init()) { 474 rc = -ENODATA; 475 goto fail_dbfs_exit; 476 } 477 if (hypfs_vm_init()) { 478 rc = -ENODATA; 479 goto fail_hypfs_diag_exit; 480 } 481 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj); 482 if (!s390_kobj) { 483 rc = -ENOMEM; 484 goto fail_hypfs_vm_exit; 485 } 486 rc = register_filesystem(&hypfs_type); 487 if (rc) 488 goto fail_filesystem; 489 return 0; 490 491 fail_filesystem: 492 kobject_put(s390_kobj); 493 fail_hypfs_vm_exit: 494 hypfs_vm_exit(); 495 fail_hypfs_diag_exit: 496 hypfs_diag_exit(); 497 fail_dbfs_exit: 498 hypfs_dbfs_exit(); 499 pr_err("Initialization of hypfs failed with rc=%i\n", rc); 500 return rc; 501 } 502 503 static void __exit hypfs_exit(void) 504 { 505 hypfs_diag_exit(); 506 hypfs_vm_exit(); 507 hypfs_dbfs_exit(); 508 unregister_filesystem(&hypfs_type); 509 kobject_put(s390_kobj); 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