1 /* 2 * arch/s390/hypfs/inode.c 3 * Hypervisor filesystem for Linux on s390. 4 * 5 * Copyright (C) IBM Corp. 2006 6 * Author(s): Michael Holzheu <holzheu@de.ibm.com> 7 */ 8 9 #include <linux/types.h> 10 #include <linux/errno.h> 11 #include <linux/fs.h> 12 #include <linux/namei.h> 13 #include <linux/vfs.h> 14 #include <linux/pagemap.h> 15 #include <linux/gfp.h> 16 #include <linux/time.h> 17 #include <linux/parser.h> 18 #include <linux/sysfs.h> 19 #include <linux/module.h> 20 #include <linux/seq_file.h> 21 #include <linux/mount.h> 22 #include <asm/ebcdic.h> 23 #include "hypfs.h" 24 25 #define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */ 26 #define TMP_SIZE 64 /* size of temporary buffers */ 27 28 static struct dentry *hypfs_create_update_file(struct super_block *sb, 29 struct dentry *dir); 30 31 struct hypfs_sb_info { 32 uid_t uid; /* uid used for files and dirs */ 33 gid_t gid; /* gid used for files and dirs */ 34 struct dentry *update_file; /* file to trigger update */ 35 time_t last_update; /* last update time in secs since 1970 */ 36 struct mutex lock; /* lock to protect update process */ 37 }; 38 39 static const struct file_operations hypfs_file_ops; 40 static struct file_system_type hypfs_type; 41 static struct super_operations hypfs_s_ops; 42 43 /* start of list of all dentries, which have to be deleted on update */ 44 static struct dentry *hypfs_last_dentry; 45 46 static void hypfs_update_update(struct super_block *sb) 47 { 48 struct hypfs_sb_info *sb_info = sb->s_fs_info; 49 struct inode *inode = sb_info->update_file->d_inode; 50 51 sb_info->last_update = get_seconds(); 52 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 53 } 54 55 /* directory tree removal functions */ 56 57 static void hypfs_add_dentry(struct dentry *dentry) 58 { 59 dentry->d_fsdata = hypfs_last_dentry; 60 hypfs_last_dentry = dentry; 61 } 62 63 static inline int hypfs_positive(struct dentry *dentry) 64 { 65 return dentry->d_inode && !d_unhashed(dentry); 66 } 67 68 static void hypfs_remove(struct dentry *dentry) 69 { 70 struct dentry *parent; 71 72 parent = dentry->d_parent; 73 if (!parent || !parent->d_inode) 74 return; 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, int 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_mode = mode; 104 ret->i_uid = hypfs_info->uid; 105 ret->i_gid = hypfs_info->gid; 106 ret->i_blocks = 0; 107 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME; 108 if (mode & S_IFDIR) 109 ret->i_nlink = 2; 110 else 111 ret->i_nlink = 1; 112 } 113 return ret; 114 } 115 116 static void hypfs_drop_inode(struct inode *inode) 117 { 118 kfree(inode->i_private); 119 generic_delete_inode(inode); 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 0; 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 size_t len; 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 count = -EINVAL; 161 goto out; 162 } 163 164 data = filp->private_data; 165 len = strlen(data); 166 if (offset > len) { 167 count = 0; 168 goto out; 169 } 170 if (count > len - offset) 171 count = len - offset; 172 if (copy_to_user(buf, data + offset, count)) { 173 count = -EFAULT; 174 goto out; 175 } 176 iocb->ki_pos += count; 177 file_accessed(filp); 178 out: 179 return count; 180 } 181 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov, 182 unsigned long nr_segs, loff_t offset) 183 { 184 int rc; 185 struct super_block *sb; 186 struct hypfs_sb_info *fs_info; 187 size_t count = iov_length(iov, nr_segs); 188 189 sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb; 190 fs_info = sb->s_fs_info; 191 /* 192 * Currently we only allow one update per second for two reasons: 193 * 1. diag 204 is VERY expensive 194 * 2. If several processes do updates in parallel and then read the 195 * hypfs data, the likelihood of collisions is reduced, if we restrict 196 * the minimum update interval. A collision occurs, if during the 197 * data gathering of one process another process triggers an update 198 * If the first process wants to ensure consistent data, it has 199 * to restart data collection in this case. 200 */ 201 mutex_lock(&fs_info->lock); 202 if (fs_info->last_update == get_seconds()) { 203 rc = -EBUSY; 204 goto out; 205 } 206 hypfs_delete_tree(sb->s_root); 207 if (MACHINE_IS_VM) 208 rc = hypfs_vm_create_files(sb, sb->s_root); 209 else 210 rc = hypfs_diag_create_files(sb, sb->s_root); 211 if (rc) { 212 printk(KERN_ERR "hypfs: Update failed\n"); 213 hypfs_delete_tree(sb->s_root); 214 goto out; 215 } 216 hypfs_update_update(sb); 217 rc = count; 218 out: 219 mutex_unlock(&fs_info->lock); 220 return rc; 221 } 222 223 static int hypfs_release(struct inode *inode, struct file *filp) 224 { 225 kfree(filp->private_data); 226 return 0; 227 } 228 229 enum { opt_uid, opt_gid, opt_err }; 230 231 static match_table_t hypfs_tokens = { 232 {opt_uid, "uid=%u"}, 233 {opt_gid, "gid=%u"}, 234 {opt_err, NULL} 235 }; 236 237 static int hypfs_parse_options(char *options, struct super_block *sb) 238 { 239 char *str; 240 substring_t args[MAX_OPT_ARGS]; 241 242 if (!options) 243 return 0; 244 while ((str = strsep(&options, ",")) != NULL) { 245 int token, option; 246 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 247 248 if (!*str) 249 continue; 250 token = match_token(str, hypfs_tokens, args); 251 switch (token) { 252 case opt_uid: 253 if (match_int(&args[0], &option)) 254 return -EINVAL; 255 hypfs_info->uid = option; 256 break; 257 case opt_gid: 258 if (match_int(&args[0], &option)) 259 return -EINVAL; 260 hypfs_info->gid = option; 261 break; 262 case opt_err: 263 default: 264 printk(KERN_ERR "hypfs: Unrecognized mount option " 265 "\"%s\" or missing value\n", str); 266 return -EINVAL; 267 } 268 } 269 return 0; 270 } 271 272 static int hypfs_show_options(struct seq_file *s, struct vfsmount *mnt) 273 { 274 struct hypfs_sb_info *hypfs_info = mnt->mnt_sb->s_fs_info; 275 276 seq_printf(s, ",uid=%u", hypfs_info->uid); 277 seq_printf(s, ",gid=%u", hypfs_info->gid); 278 return 0; 279 } 280 281 static int hypfs_fill_super(struct super_block *sb, void *data, int silent) 282 { 283 struct inode *root_inode; 284 struct dentry *root_dentry; 285 int rc = 0; 286 struct hypfs_sb_info *sbi; 287 288 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); 289 if (!sbi) 290 return -ENOMEM; 291 mutex_init(&sbi->lock); 292 sbi->uid = current->uid; 293 sbi->gid = current->gid; 294 sb->s_fs_info = sbi; 295 sb->s_blocksize = PAGE_CACHE_SIZE; 296 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 297 sb->s_magic = HYPFS_MAGIC; 298 sb->s_op = &hypfs_s_ops; 299 if (hypfs_parse_options(data, sb)) { 300 rc = -EINVAL; 301 goto err_alloc; 302 } 303 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755); 304 if (!root_inode) { 305 rc = -ENOMEM; 306 goto err_alloc; 307 } 308 root_inode->i_op = &simple_dir_inode_operations; 309 root_inode->i_fop = &simple_dir_operations; 310 root_dentry = d_alloc_root(root_inode); 311 if (!root_dentry) { 312 iput(root_inode); 313 rc = -ENOMEM; 314 goto err_alloc; 315 } 316 if (MACHINE_IS_VM) 317 rc = hypfs_vm_create_files(sb, root_dentry); 318 else 319 rc = hypfs_diag_create_files(sb, root_dentry); 320 if (rc) 321 goto err_tree; 322 sbi->update_file = hypfs_create_update_file(sb, root_dentry); 323 if (IS_ERR(sbi->update_file)) { 324 rc = PTR_ERR(sbi->update_file); 325 goto err_tree; 326 } 327 hypfs_update_update(sb); 328 sb->s_root = root_dentry; 329 printk(KERN_INFO "hypfs: Hypervisor filesystem mounted\n"); 330 return 0; 331 332 err_tree: 333 hypfs_delete_tree(root_dentry); 334 d_genocide(root_dentry); 335 dput(root_dentry); 336 err_alloc: 337 kfree(sbi); 338 return rc; 339 } 340 341 static int hypfs_get_super(struct file_system_type *fst, int flags, 342 const char *devname, void *data, struct vfsmount *mnt) 343 { 344 return get_sb_single(fst, flags, data, hypfs_fill_super, mnt); 345 } 346 347 static void hypfs_kill_super(struct super_block *sb) 348 { 349 struct hypfs_sb_info *sb_info = sb->s_fs_info; 350 351 if (sb->s_root) { 352 hypfs_delete_tree(sb->s_root); 353 hypfs_remove(sb_info->update_file); 354 kfree(sb->s_fs_info); 355 sb->s_fs_info = NULL; 356 } 357 kill_litter_super(sb); 358 } 359 360 static struct dentry *hypfs_create_file(struct super_block *sb, 361 struct dentry *parent, const char *name, 362 char *data, mode_t mode) 363 { 364 struct dentry *dentry; 365 struct inode *inode; 366 struct qstr qname; 367 368 qname.name = name; 369 qname.len = strlen(name); 370 qname.hash = full_name_hash(name, qname.len); 371 mutex_lock(&parent->d_inode->i_mutex); 372 dentry = lookup_one_len(name, parent, strlen(name)); 373 if (IS_ERR(dentry)) { 374 dentry = ERR_PTR(-ENOMEM); 375 goto fail; 376 } 377 inode = hypfs_make_inode(sb, mode); 378 if (!inode) { 379 dput(dentry); 380 dentry = ERR_PTR(-ENOMEM); 381 goto fail; 382 } 383 if (mode & S_IFREG) { 384 inode->i_fop = &hypfs_file_ops; 385 if (data) 386 inode->i_size = strlen(data); 387 else 388 inode->i_size = 0; 389 } else if (mode & S_IFDIR) { 390 inode->i_op = &simple_dir_inode_operations; 391 inode->i_fop = &simple_dir_operations; 392 parent->d_inode->i_nlink++; 393 } else 394 BUG(); 395 inode->i_private = data; 396 d_instantiate(dentry, inode); 397 dget(dentry); 398 fail: 399 mutex_unlock(&parent->d_inode->i_mutex); 400 return dentry; 401 } 402 403 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent, 404 const char *name) 405 { 406 struct dentry *dentry; 407 408 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE); 409 if (IS_ERR(dentry)) 410 return dentry; 411 hypfs_add_dentry(dentry); 412 return dentry; 413 } 414 415 static struct dentry *hypfs_create_update_file(struct super_block *sb, 416 struct dentry *dir) 417 { 418 struct dentry *dentry; 419 420 dentry = hypfs_create_file(sb, dir, "update", NULL, 421 S_IFREG | UPDATE_FILE_MODE); 422 /* 423 * We do not put the update file on the 'delete' list with 424 * hypfs_add_dentry(), since it should not be removed when the tree 425 * is updated. 426 */ 427 return dentry; 428 } 429 430 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir, 431 const char *name, __u64 value) 432 { 433 char *buffer; 434 char tmp[TMP_SIZE]; 435 struct dentry *dentry; 436 437 snprintf(tmp, TMP_SIZE, "%lld\n", (unsigned long long int)value); 438 buffer = kstrdup(tmp, GFP_KERNEL); 439 if (!buffer) 440 return ERR_PTR(-ENOMEM); 441 dentry = 442 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 443 if (IS_ERR(dentry)) { 444 kfree(buffer); 445 return ERR_PTR(-ENOMEM); 446 } 447 hypfs_add_dentry(dentry); 448 return dentry; 449 } 450 451 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir, 452 const char *name, char *string) 453 { 454 char *buffer; 455 struct dentry *dentry; 456 457 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); 458 if (!buffer) 459 return ERR_PTR(-ENOMEM); 460 sprintf(buffer, "%s\n", string); 461 dentry = 462 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 463 if (IS_ERR(dentry)) { 464 kfree(buffer); 465 return ERR_PTR(-ENOMEM); 466 } 467 hypfs_add_dentry(dentry); 468 return dentry; 469 } 470 471 static const struct file_operations hypfs_file_ops = { 472 .open = hypfs_open, 473 .release = hypfs_release, 474 .read = do_sync_read, 475 .write = do_sync_write, 476 .aio_read = hypfs_aio_read, 477 .aio_write = hypfs_aio_write, 478 }; 479 480 static struct file_system_type hypfs_type = { 481 .owner = THIS_MODULE, 482 .name = "s390_hypfs", 483 .get_sb = hypfs_get_super, 484 .kill_sb = hypfs_kill_super 485 }; 486 487 static struct super_operations hypfs_s_ops = { 488 .statfs = simple_statfs, 489 .drop_inode = hypfs_drop_inode, 490 .show_options = hypfs_show_options, 491 }; 492 493 static struct kobject *s390_kobj; 494 495 static int __init hypfs_init(void) 496 { 497 int rc; 498 499 if (MACHINE_IS_VM) { 500 if (hypfs_vm_init()) 501 /* no diag 2fc, just exit */ 502 return -ENODATA; 503 } else { 504 if (hypfs_diag_init()) { 505 rc = -ENODATA; 506 goto fail_diag; 507 } 508 } 509 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj); 510 if (!s390_kobj) { 511 rc = -ENOMEM;; 512 goto fail_sysfs; 513 } 514 rc = register_filesystem(&hypfs_type); 515 if (rc) 516 goto fail_filesystem; 517 return 0; 518 519 fail_filesystem: 520 kobject_put(s390_kobj); 521 fail_sysfs: 522 if (!MACHINE_IS_VM) 523 hypfs_diag_exit(); 524 fail_diag: 525 printk(KERN_ERR "hypfs: Initialization failed with rc = %i.\n", rc); 526 return rc; 527 } 528 529 static void __exit hypfs_exit(void) 530 { 531 if (!MACHINE_IS_VM) 532 hypfs_diag_exit(); 533 unregister_filesystem(&hypfs_type); 534 kobject_put(s390_kobj); 535 } 536 537 module_init(hypfs_init) 538 module_exit(hypfs_exit) 539 540 MODULE_LICENSE("GPL"); 541 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>"); 542 MODULE_DESCRIPTION("s390 Hypervisor Filesystem"); 543