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/pagemap.h> 18 #include <linux/gfp.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 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, int 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 (mode & S_IFDIR) 111 ret->i_nlink = 2; 112 else 113 ret->i_nlink = 1; 114 } 115 return ret; 116 } 117 118 static void hypfs_drop_inode(struct inode *inode) 119 { 120 kfree(inode->i_private); 121 generic_delete_inode(inode); 122 } 123 124 static int hypfs_open(struct inode *inode, struct file *filp) 125 { 126 char *data = filp->f_path.dentry->d_inode->i_private; 127 struct hypfs_sb_info *fs_info; 128 129 if (filp->f_mode & FMODE_WRITE) { 130 if (!(inode->i_mode & S_IWUGO)) 131 return -EACCES; 132 } 133 if (filp->f_mode & FMODE_READ) { 134 if (!(inode->i_mode & S_IRUGO)) 135 return -EACCES; 136 } 137 138 fs_info = inode->i_sb->s_fs_info; 139 if(data) { 140 mutex_lock(&fs_info->lock); 141 filp->private_data = kstrdup(data, GFP_KERNEL); 142 if (!filp->private_data) { 143 mutex_unlock(&fs_info->lock); 144 return -ENOMEM; 145 } 146 mutex_unlock(&fs_info->lock); 147 } 148 return 0; 149 } 150 151 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov, 152 unsigned long nr_segs, loff_t offset) 153 { 154 char *data; 155 ssize_t ret; 156 struct file *filp = iocb->ki_filp; 157 /* XXX: temporary */ 158 char __user *buf = iov[0].iov_base; 159 size_t count = iov[0].iov_len; 160 161 if (nr_segs != 1) 162 return -EINVAL; 163 164 data = filp->private_data; 165 ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data)); 166 if (ret <= 0) 167 return ret; 168 169 iocb->ki_pos += ret; 170 file_accessed(filp); 171 172 return ret; 173 } 174 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov, 175 unsigned long nr_segs, loff_t offset) 176 { 177 int rc; 178 struct super_block *sb; 179 struct hypfs_sb_info *fs_info; 180 size_t count = iov_length(iov, nr_segs); 181 182 sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb; 183 fs_info = sb->s_fs_info; 184 /* 185 * Currently we only allow one update per second for two reasons: 186 * 1. diag 204 is VERY expensive 187 * 2. If several processes do updates in parallel and then read the 188 * hypfs data, the likelihood of collisions is reduced, if we restrict 189 * the minimum update interval. A collision occurs, if during the 190 * data gathering of one process another process triggers an update 191 * If the first process wants to ensure consistent data, it has 192 * to restart data collection in this case. 193 */ 194 mutex_lock(&fs_info->lock); 195 if (fs_info->last_update == get_seconds()) { 196 rc = -EBUSY; 197 goto out; 198 } 199 hypfs_delete_tree(sb->s_root); 200 if (MACHINE_IS_VM) 201 rc = hypfs_vm_create_files(sb, sb->s_root); 202 else 203 rc = hypfs_diag_create_files(sb, sb->s_root); 204 if (rc) { 205 pr_err("Updating the hypfs tree failed\n"); 206 hypfs_delete_tree(sb->s_root); 207 goto out; 208 } 209 hypfs_update_update(sb); 210 rc = count; 211 out: 212 mutex_unlock(&fs_info->lock); 213 return rc; 214 } 215 216 static int hypfs_release(struct inode *inode, struct file *filp) 217 { 218 kfree(filp->private_data); 219 return 0; 220 } 221 222 enum { opt_uid, opt_gid, opt_err }; 223 224 static const match_table_t hypfs_tokens = { 225 {opt_uid, "uid=%u"}, 226 {opt_gid, "gid=%u"}, 227 {opt_err, NULL} 228 }; 229 230 static int hypfs_parse_options(char *options, struct super_block *sb) 231 { 232 char *str; 233 substring_t args[MAX_OPT_ARGS]; 234 235 if (!options) 236 return 0; 237 while ((str = strsep(&options, ",")) != NULL) { 238 int token, option; 239 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 240 241 if (!*str) 242 continue; 243 token = match_token(str, hypfs_tokens, args); 244 switch (token) { 245 case opt_uid: 246 if (match_int(&args[0], &option)) 247 return -EINVAL; 248 hypfs_info->uid = option; 249 break; 250 case opt_gid: 251 if (match_int(&args[0], &option)) 252 return -EINVAL; 253 hypfs_info->gid = option; 254 break; 255 case opt_err: 256 default: 257 pr_err("%s is not a valid mount option\n", str); 258 return -EINVAL; 259 } 260 } 261 return 0; 262 } 263 264 static int hypfs_show_options(struct seq_file *s, struct vfsmount *mnt) 265 { 266 struct hypfs_sb_info *hypfs_info = mnt->mnt_sb->s_fs_info; 267 268 seq_printf(s, ",uid=%u", hypfs_info->uid); 269 seq_printf(s, ",gid=%u", hypfs_info->gid); 270 return 0; 271 } 272 273 static int hypfs_fill_super(struct super_block *sb, void *data, int silent) 274 { 275 struct inode *root_inode; 276 struct dentry *root_dentry; 277 int rc = 0; 278 struct hypfs_sb_info *sbi; 279 280 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); 281 if (!sbi) 282 return -ENOMEM; 283 mutex_init(&sbi->lock); 284 sbi->uid = current_uid(); 285 sbi->gid = current_gid(); 286 sb->s_fs_info = sbi; 287 sb->s_blocksize = PAGE_CACHE_SIZE; 288 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 289 sb->s_magic = HYPFS_MAGIC; 290 sb->s_op = &hypfs_s_ops; 291 if (hypfs_parse_options(data, sb)) { 292 rc = -EINVAL; 293 goto err_alloc; 294 } 295 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755); 296 if (!root_inode) { 297 rc = -ENOMEM; 298 goto err_alloc; 299 } 300 root_inode->i_op = &simple_dir_inode_operations; 301 root_inode->i_fop = &simple_dir_operations; 302 root_dentry = d_alloc_root(root_inode); 303 if (!root_dentry) { 304 iput(root_inode); 305 rc = -ENOMEM; 306 goto err_alloc; 307 } 308 if (MACHINE_IS_VM) 309 rc = hypfs_vm_create_files(sb, root_dentry); 310 else 311 rc = hypfs_diag_create_files(sb, root_dentry); 312 if (rc) 313 goto err_tree; 314 sbi->update_file = hypfs_create_update_file(sb, root_dentry); 315 if (IS_ERR(sbi->update_file)) { 316 rc = PTR_ERR(sbi->update_file); 317 goto err_tree; 318 } 319 hypfs_update_update(sb); 320 sb->s_root = root_dentry; 321 pr_info("Hypervisor filesystem mounted\n"); 322 return 0; 323 324 err_tree: 325 hypfs_delete_tree(root_dentry); 326 d_genocide(root_dentry); 327 dput(root_dentry); 328 err_alloc: 329 kfree(sbi); 330 return rc; 331 } 332 333 static int hypfs_get_super(struct file_system_type *fst, int flags, 334 const char *devname, void *data, struct vfsmount *mnt) 335 { 336 return get_sb_single(fst, flags, data, hypfs_fill_super, mnt); 337 } 338 339 static void hypfs_kill_super(struct super_block *sb) 340 { 341 struct hypfs_sb_info *sb_info = sb->s_fs_info; 342 343 if (sb->s_root) { 344 hypfs_delete_tree(sb->s_root); 345 hypfs_remove(sb_info->update_file); 346 kfree(sb->s_fs_info); 347 sb->s_fs_info = NULL; 348 } 349 kill_litter_super(sb); 350 } 351 352 static struct dentry *hypfs_create_file(struct super_block *sb, 353 struct dentry *parent, const char *name, 354 char *data, mode_t mode) 355 { 356 struct dentry *dentry; 357 struct inode *inode; 358 struct qstr qname; 359 360 qname.name = name; 361 qname.len = strlen(name); 362 qname.hash = full_name_hash(name, qname.len); 363 mutex_lock(&parent->d_inode->i_mutex); 364 dentry = lookup_one_len(name, parent, strlen(name)); 365 if (IS_ERR(dentry)) { 366 dentry = ERR_PTR(-ENOMEM); 367 goto fail; 368 } 369 inode = hypfs_make_inode(sb, mode); 370 if (!inode) { 371 dput(dentry); 372 dentry = ERR_PTR(-ENOMEM); 373 goto fail; 374 } 375 if (mode & S_IFREG) { 376 inode->i_fop = &hypfs_file_ops; 377 if (data) 378 inode->i_size = strlen(data); 379 else 380 inode->i_size = 0; 381 } else if (mode & S_IFDIR) { 382 inode->i_op = &simple_dir_inode_operations; 383 inode->i_fop = &simple_dir_operations; 384 parent->d_inode->i_nlink++; 385 } else 386 BUG(); 387 inode->i_private = data; 388 d_instantiate(dentry, inode); 389 dget(dentry); 390 fail: 391 mutex_unlock(&parent->d_inode->i_mutex); 392 return dentry; 393 } 394 395 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent, 396 const char *name) 397 { 398 struct dentry *dentry; 399 400 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE); 401 if (IS_ERR(dentry)) 402 return dentry; 403 hypfs_add_dentry(dentry); 404 return dentry; 405 } 406 407 static struct dentry *hypfs_create_update_file(struct super_block *sb, 408 struct dentry *dir) 409 { 410 struct dentry *dentry; 411 412 dentry = hypfs_create_file(sb, dir, "update", NULL, 413 S_IFREG | UPDATE_FILE_MODE); 414 /* 415 * We do not put the update file on the 'delete' list with 416 * hypfs_add_dentry(), since it should not be removed when the tree 417 * is updated. 418 */ 419 return dentry; 420 } 421 422 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir, 423 const char *name, __u64 value) 424 { 425 char *buffer; 426 char tmp[TMP_SIZE]; 427 struct dentry *dentry; 428 429 snprintf(tmp, TMP_SIZE, "%lld\n", (unsigned long long int)value); 430 buffer = kstrdup(tmp, GFP_KERNEL); 431 if (!buffer) 432 return ERR_PTR(-ENOMEM); 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 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir, 444 const char *name, char *string) 445 { 446 char *buffer; 447 struct dentry *dentry; 448 449 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); 450 if (!buffer) 451 return ERR_PTR(-ENOMEM); 452 sprintf(buffer, "%s\n", string); 453 dentry = 454 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 455 if (IS_ERR(dentry)) { 456 kfree(buffer); 457 return ERR_PTR(-ENOMEM); 458 } 459 hypfs_add_dentry(dentry); 460 return dentry; 461 } 462 463 static const struct file_operations hypfs_file_ops = { 464 .open = hypfs_open, 465 .release = hypfs_release, 466 .read = do_sync_read, 467 .write = do_sync_write, 468 .aio_read = hypfs_aio_read, 469 .aio_write = hypfs_aio_write, 470 }; 471 472 static struct file_system_type hypfs_type = { 473 .owner = THIS_MODULE, 474 .name = "s390_hypfs", 475 .get_sb = hypfs_get_super, 476 .kill_sb = hypfs_kill_super 477 }; 478 479 static struct super_operations hypfs_s_ops = { 480 .statfs = simple_statfs, 481 .drop_inode = hypfs_drop_inode, 482 .show_options = hypfs_show_options, 483 }; 484 485 static struct kobject *s390_kobj; 486 487 static int __init hypfs_init(void) 488 { 489 int rc; 490 491 if (MACHINE_IS_VM) { 492 if (hypfs_vm_init()) 493 /* no diag 2fc, just exit */ 494 return -ENODATA; 495 } else { 496 if (hypfs_diag_init()) { 497 rc = -ENODATA; 498 goto fail_diag; 499 } 500 } 501 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj); 502 if (!s390_kobj) { 503 rc = -ENOMEM;; 504 goto fail_sysfs; 505 } 506 rc = register_filesystem(&hypfs_type); 507 if (rc) 508 goto fail_filesystem; 509 return 0; 510 511 fail_filesystem: 512 kobject_put(s390_kobj); 513 fail_sysfs: 514 if (!MACHINE_IS_VM) 515 hypfs_diag_exit(); 516 fail_diag: 517 pr_err("Initialization of hypfs failed with rc=%i\n", rc); 518 return rc; 519 } 520 521 static void __exit hypfs_exit(void) 522 { 523 if (!MACHINE_IS_VM) 524 hypfs_diag_exit(); 525 unregister_filesystem(&hypfs_type); 526 kobject_put(s390_kobj); 527 } 528 529 module_init(hypfs_init) 530 module_exit(hypfs_exit) 531 532 MODULE_LICENSE("GPL"); 533 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>"); 534 MODULE_DESCRIPTION("s390 Hypervisor Filesystem"); 535