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 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 printk(KERN_ERR "hypfs: Update 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 printk(KERN_ERR "hypfs: Unrecognized mount option " 256 "\"%s\" or missing value\n", str); 257 return -EINVAL; 258 } 259 } 260 return 0; 261 } 262 263 static int hypfs_show_options(struct seq_file *s, struct vfsmount *mnt) 264 { 265 struct hypfs_sb_info *hypfs_info = mnt->mnt_sb->s_fs_info; 266 267 seq_printf(s, ",uid=%u", hypfs_info->uid); 268 seq_printf(s, ",gid=%u", hypfs_info->gid); 269 return 0; 270 } 271 272 static int hypfs_fill_super(struct super_block *sb, void *data, int silent) 273 { 274 struct inode *root_inode; 275 struct dentry *root_dentry; 276 int rc = 0; 277 struct hypfs_sb_info *sbi; 278 279 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); 280 if (!sbi) 281 return -ENOMEM; 282 mutex_init(&sbi->lock); 283 sbi->uid = current->uid; 284 sbi->gid = current->gid; 285 sb->s_fs_info = sbi; 286 sb->s_blocksize = PAGE_CACHE_SIZE; 287 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 288 sb->s_magic = HYPFS_MAGIC; 289 sb->s_op = &hypfs_s_ops; 290 if (hypfs_parse_options(data, sb)) { 291 rc = -EINVAL; 292 goto err_alloc; 293 } 294 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755); 295 if (!root_inode) { 296 rc = -ENOMEM; 297 goto err_alloc; 298 } 299 root_inode->i_op = &simple_dir_inode_operations; 300 root_inode->i_fop = &simple_dir_operations; 301 root_dentry = d_alloc_root(root_inode); 302 if (!root_dentry) { 303 iput(root_inode); 304 rc = -ENOMEM; 305 goto err_alloc; 306 } 307 if (MACHINE_IS_VM) 308 rc = hypfs_vm_create_files(sb, root_dentry); 309 else 310 rc = hypfs_diag_create_files(sb, root_dentry); 311 if (rc) 312 goto err_tree; 313 sbi->update_file = hypfs_create_update_file(sb, root_dentry); 314 if (IS_ERR(sbi->update_file)) { 315 rc = PTR_ERR(sbi->update_file); 316 goto err_tree; 317 } 318 hypfs_update_update(sb); 319 sb->s_root = root_dentry; 320 printk(KERN_INFO "hypfs: Hypervisor filesystem mounted\n"); 321 return 0; 322 323 err_tree: 324 hypfs_delete_tree(root_dentry); 325 d_genocide(root_dentry); 326 dput(root_dentry); 327 err_alloc: 328 kfree(sbi); 329 return rc; 330 } 331 332 static int hypfs_get_super(struct file_system_type *fst, int flags, 333 const char *devname, void *data, struct vfsmount *mnt) 334 { 335 return get_sb_single(fst, flags, data, hypfs_fill_super, mnt); 336 } 337 338 static void hypfs_kill_super(struct super_block *sb) 339 { 340 struct hypfs_sb_info *sb_info = sb->s_fs_info; 341 342 if (sb->s_root) { 343 hypfs_delete_tree(sb->s_root); 344 hypfs_remove(sb_info->update_file); 345 kfree(sb->s_fs_info); 346 sb->s_fs_info = NULL; 347 } 348 kill_litter_super(sb); 349 } 350 351 static struct dentry *hypfs_create_file(struct super_block *sb, 352 struct dentry *parent, const char *name, 353 char *data, mode_t mode) 354 { 355 struct dentry *dentry; 356 struct inode *inode; 357 struct qstr qname; 358 359 qname.name = name; 360 qname.len = strlen(name); 361 qname.hash = full_name_hash(name, qname.len); 362 mutex_lock(&parent->d_inode->i_mutex); 363 dentry = lookup_one_len(name, parent, strlen(name)); 364 if (IS_ERR(dentry)) { 365 dentry = ERR_PTR(-ENOMEM); 366 goto fail; 367 } 368 inode = hypfs_make_inode(sb, mode); 369 if (!inode) { 370 dput(dentry); 371 dentry = ERR_PTR(-ENOMEM); 372 goto fail; 373 } 374 if (mode & S_IFREG) { 375 inode->i_fop = &hypfs_file_ops; 376 if (data) 377 inode->i_size = strlen(data); 378 else 379 inode->i_size = 0; 380 } else if (mode & S_IFDIR) { 381 inode->i_op = &simple_dir_inode_operations; 382 inode->i_fop = &simple_dir_operations; 383 parent->d_inode->i_nlink++; 384 } else 385 BUG(); 386 inode->i_private = data; 387 d_instantiate(dentry, inode); 388 dget(dentry); 389 fail: 390 mutex_unlock(&parent->d_inode->i_mutex); 391 return dentry; 392 } 393 394 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent, 395 const char *name) 396 { 397 struct dentry *dentry; 398 399 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE); 400 if (IS_ERR(dentry)) 401 return dentry; 402 hypfs_add_dentry(dentry); 403 return dentry; 404 } 405 406 static struct dentry *hypfs_create_update_file(struct super_block *sb, 407 struct dentry *dir) 408 { 409 struct dentry *dentry; 410 411 dentry = hypfs_create_file(sb, dir, "update", NULL, 412 S_IFREG | UPDATE_FILE_MODE); 413 /* 414 * We do not put the update file on the 'delete' list with 415 * hypfs_add_dentry(), since it should not be removed when the tree 416 * is updated. 417 */ 418 return dentry; 419 } 420 421 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir, 422 const char *name, __u64 value) 423 { 424 char *buffer; 425 char tmp[TMP_SIZE]; 426 struct dentry *dentry; 427 428 snprintf(tmp, TMP_SIZE, "%lld\n", (unsigned long long int)value); 429 buffer = kstrdup(tmp, GFP_KERNEL); 430 if (!buffer) 431 return ERR_PTR(-ENOMEM); 432 dentry = 433 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 434 if (IS_ERR(dentry)) { 435 kfree(buffer); 436 return ERR_PTR(-ENOMEM); 437 } 438 hypfs_add_dentry(dentry); 439 return dentry; 440 } 441 442 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir, 443 const char *name, char *string) 444 { 445 char *buffer; 446 struct dentry *dentry; 447 448 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); 449 if (!buffer) 450 return ERR_PTR(-ENOMEM); 451 sprintf(buffer, "%s\n", string); 452 dentry = 453 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 454 if (IS_ERR(dentry)) { 455 kfree(buffer); 456 return ERR_PTR(-ENOMEM); 457 } 458 hypfs_add_dentry(dentry); 459 return dentry; 460 } 461 462 static const struct file_operations hypfs_file_ops = { 463 .open = hypfs_open, 464 .release = hypfs_release, 465 .read = do_sync_read, 466 .write = do_sync_write, 467 .aio_read = hypfs_aio_read, 468 .aio_write = hypfs_aio_write, 469 }; 470 471 static struct file_system_type hypfs_type = { 472 .owner = THIS_MODULE, 473 .name = "s390_hypfs", 474 .get_sb = hypfs_get_super, 475 .kill_sb = hypfs_kill_super 476 }; 477 478 static struct super_operations hypfs_s_ops = { 479 .statfs = simple_statfs, 480 .drop_inode = hypfs_drop_inode, 481 .show_options = hypfs_show_options, 482 }; 483 484 static struct kobject *s390_kobj; 485 486 static int __init hypfs_init(void) 487 { 488 int rc; 489 490 if (MACHINE_IS_VM) { 491 if (hypfs_vm_init()) 492 /* no diag 2fc, just exit */ 493 return -ENODATA; 494 } else { 495 if (hypfs_diag_init()) { 496 rc = -ENODATA; 497 goto fail_diag; 498 } 499 } 500 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj); 501 if (!s390_kobj) { 502 rc = -ENOMEM;; 503 goto fail_sysfs; 504 } 505 rc = register_filesystem(&hypfs_type); 506 if (rc) 507 goto fail_filesystem; 508 return 0; 509 510 fail_filesystem: 511 kobject_put(s390_kobj); 512 fail_sysfs: 513 if (!MACHINE_IS_VM) 514 hypfs_diag_exit(); 515 fail_diag: 516 printk(KERN_ERR "hypfs: Initialization failed with rc = %i.\n", rc); 517 return rc; 518 } 519 520 static void __exit hypfs_exit(void) 521 { 522 if (!MACHINE_IS_VM) 523 hypfs_diag_exit(); 524 unregister_filesystem(&hypfs_type); 525 kobject_put(s390_kobj); 526 } 527 528 module_init(hypfs_init) 529 module_exit(hypfs_exit) 530 531 MODULE_LICENSE("GPL"); 532 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>"); 533 MODULE_DESCRIPTION("s390 Hypervisor Filesystem"); 534