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 struct dentry *hypfs_dbfs_dir; 50 51 static void hypfs_update_update(struct super_block *sb) 52 { 53 struct hypfs_sb_info *sb_info = sb->s_fs_info; 54 struct inode *inode = sb_info->update_file->d_inode; 55 56 sb_info->last_update = get_seconds(); 57 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 58 } 59 60 /* directory tree removal functions */ 61 62 static void hypfs_add_dentry(struct dentry *dentry) 63 { 64 dentry->d_fsdata = hypfs_last_dentry; 65 hypfs_last_dentry = dentry; 66 } 67 68 static inline int hypfs_positive(struct dentry *dentry) 69 { 70 return dentry->d_inode && !d_unhashed(dentry); 71 } 72 73 static void hypfs_remove(struct dentry *dentry) 74 { 75 struct dentry *parent; 76 77 parent = dentry->d_parent; 78 if (!parent || !parent->d_inode) 79 return; 80 mutex_lock(&parent->d_inode->i_mutex); 81 if (hypfs_positive(dentry)) { 82 if (S_ISDIR(dentry->d_inode->i_mode)) 83 simple_rmdir(parent->d_inode, dentry); 84 else 85 simple_unlink(parent->d_inode, dentry); 86 } 87 d_delete(dentry); 88 dput(dentry); 89 mutex_unlock(&parent->d_inode->i_mutex); 90 } 91 92 static void hypfs_delete_tree(struct dentry *root) 93 { 94 while (hypfs_last_dentry) { 95 struct dentry *next_dentry; 96 next_dentry = hypfs_last_dentry->d_fsdata; 97 hypfs_remove(hypfs_last_dentry); 98 hypfs_last_dentry = next_dentry; 99 } 100 } 101 102 static struct inode *hypfs_make_inode(struct super_block *sb, int mode) 103 { 104 struct inode *ret = new_inode(sb); 105 106 if (ret) { 107 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 108 ret->i_mode = mode; 109 ret->i_uid = hypfs_info->uid; 110 ret->i_gid = hypfs_info->gid; 111 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME; 112 if (mode & S_IFDIR) 113 ret->i_nlink = 2; 114 else 115 ret->i_nlink = 1; 116 } 117 return ret; 118 } 119 120 static void hypfs_evict_inode(struct inode *inode) 121 { 122 end_writeback(inode); 123 kfree(inode->i_private); 124 } 125 126 static int hypfs_open(struct inode *inode, struct file *filp) 127 { 128 char *data = filp->f_path.dentry->d_inode->i_private; 129 struct hypfs_sb_info *fs_info; 130 131 if (filp->f_mode & FMODE_WRITE) { 132 if (!(inode->i_mode & S_IWUGO)) 133 return -EACCES; 134 } 135 if (filp->f_mode & FMODE_READ) { 136 if (!(inode->i_mode & S_IRUGO)) 137 return -EACCES; 138 } 139 140 fs_info = inode->i_sb->s_fs_info; 141 if(data) { 142 mutex_lock(&fs_info->lock); 143 filp->private_data = kstrdup(data, GFP_KERNEL); 144 if (!filp->private_data) { 145 mutex_unlock(&fs_info->lock); 146 return -ENOMEM; 147 } 148 mutex_unlock(&fs_info->lock); 149 } 150 return nonseekable_open(inode, filp); 151 } 152 153 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov, 154 unsigned long nr_segs, loff_t offset) 155 { 156 char *data; 157 ssize_t ret; 158 struct file *filp = iocb->ki_filp; 159 /* XXX: temporary */ 160 char __user *buf = iov[0].iov_base; 161 size_t count = iov[0].iov_len; 162 163 if (nr_segs != 1) 164 return -EINVAL; 165 166 data = filp->private_data; 167 ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data)); 168 if (ret <= 0) 169 return ret; 170 171 iocb->ki_pos += ret; 172 file_accessed(filp); 173 174 return ret; 175 } 176 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov, 177 unsigned long nr_segs, loff_t offset) 178 { 179 int rc; 180 struct super_block *sb; 181 struct hypfs_sb_info *fs_info; 182 size_t count = iov_length(iov, nr_segs); 183 184 sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb; 185 fs_info = sb->s_fs_info; 186 /* 187 * Currently we only allow one update per second for two reasons: 188 * 1. diag 204 is VERY expensive 189 * 2. If several processes do updates in parallel and then read the 190 * hypfs data, the likelihood of collisions is reduced, if we restrict 191 * the minimum update interval. A collision occurs, if during the 192 * data gathering of one process another process triggers an update 193 * If the first process wants to ensure consistent data, it has 194 * to restart data collection in this case. 195 */ 196 mutex_lock(&fs_info->lock); 197 if (fs_info->last_update == get_seconds()) { 198 rc = -EBUSY; 199 goto out; 200 } 201 hypfs_delete_tree(sb->s_root); 202 if (MACHINE_IS_VM) 203 rc = hypfs_vm_create_files(sb, sb->s_root); 204 else 205 rc = hypfs_diag_create_files(sb, sb->s_root); 206 if (rc) { 207 pr_err("Updating the hypfs tree failed\n"); 208 hypfs_delete_tree(sb->s_root); 209 goto out; 210 } 211 hypfs_update_update(sb); 212 rc = count; 213 out: 214 mutex_unlock(&fs_info->lock); 215 return rc; 216 } 217 218 static int hypfs_release(struct inode *inode, struct file *filp) 219 { 220 kfree(filp->private_data); 221 return 0; 222 } 223 224 enum { opt_uid, opt_gid, opt_err }; 225 226 static const match_table_t hypfs_tokens = { 227 {opt_uid, "uid=%u"}, 228 {opt_gid, "gid=%u"}, 229 {opt_err, NULL} 230 }; 231 232 static int hypfs_parse_options(char *options, struct super_block *sb) 233 { 234 char *str; 235 substring_t args[MAX_OPT_ARGS]; 236 237 if (!options) 238 return 0; 239 while ((str = strsep(&options, ",")) != NULL) { 240 int token, option; 241 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 242 243 if (!*str) 244 continue; 245 token = match_token(str, hypfs_tokens, args); 246 switch (token) { 247 case opt_uid: 248 if (match_int(&args[0], &option)) 249 return -EINVAL; 250 hypfs_info->uid = option; 251 break; 252 case opt_gid: 253 if (match_int(&args[0], &option)) 254 return -EINVAL; 255 hypfs_info->gid = option; 256 break; 257 case opt_err: 258 default: 259 pr_err("%s is not a valid mount option\n", str); 260 return -EINVAL; 261 } 262 } 263 return 0; 264 } 265 266 static int hypfs_show_options(struct seq_file *s, struct vfsmount *mnt) 267 { 268 struct hypfs_sb_info *hypfs_info = mnt->mnt_sb->s_fs_info; 269 270 seq_printf(s, ",uid=%u", hypfs_info->uid); 271 seq_printf(s, ",gid=%u", hypfs_info->gid); 272 return 0; 273 } 274 275 static int hypfs_fill_super(struct super_block *sb, void *data, int silent) 276 { 277 struct inode *root_inode; 278 struct dentry *root_dentry; 279 int rc = 0; 280 struct hypfs_sb_info *sbi; 281 282 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); 283 if (!sbi) 284 return -ENOMEM; 285 mutex_init(&sbi->lock); 286 sbi->uid = current_uid(); 287 sbi->gid = current_gid(); 288 sb->s_fs_info = sbi; 289 sb->s_blocksize = PAGE_CACHE_SIZE; 290 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 291 sb->s_magic = HYPFS_MAGIC; 292 sb->s_op = &hypfs_s_ops; 293 if (hypfs_parse_options(data, sb)) 294 return -EINVAL; 295 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755); 296 if (!root_inode) 297 return -ENOMEM; 298 root_inode->i_op = &simple_dir_inode_operations; 299 root_inode->i_fop = &simple_dir_operations; 300 sb->s_root = root_dentry = d_alloc_root(root_inode); 301 if (!root_dentry) { 302 iput(root_inode); 303 return -ENOMEM; 304 } 305 if (MACHINE_IS_VM) 306 rc = hypfs_vm_create_files(sb, root_dentry); 307 else 308 rc = hypfs_diag_create_files(sb, root_dentry); 309 if (rc) 310 return rc; 311 sbi->update_file = hypfs_create_update_file(sb, root_dentry); 312 if (IS_ERR(sbi->update_file)) 313 return PTR_ERR(sbi->update_file); 314 hypfs_update_update(sb); 315 pr_info("Hypervisor filesystem mounted\n"); 316 return 0; 317 } 318 319 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags, 320 const char *devname, void *data) 321 { 322 return mount_single(fst, flags, data, hypfs_fill_super); 323 } 324 325 static void hypfs_kill_super(struct super_block *sb) 326 { 327 struct hypfs_sb_info *sb_info = sb->s_fs_info; 328 329 if (sb->s_root) 330 hypfs_delete_tree(sb->s_root); 331 if (sb_info->update_file) 332 hypfs_remove(sb_info->update_file); 333 kfree(sb->s_fs_info); 334 sb->s_fs_info = NULL; 335 kill_litter_super(sb); 336 } 337 338 static struct dentry *hypfs_create_file(struct super_block *sb, 339 struct dentry *parent, const char *name, 340 char *data, mode_t mode) 341 { 342 struct dentry *dentry; 343 struct inode *inode; 344 345 mutex_lock(&parent->d_inode->i_mutex); 346 dentry = lookup_one_len(name, parent, strlen(name)); 347 if (IS_ERR(dentry)) { 348 dentry = ERR_PTR(-ENOMEM); 349 goto fail; 350 } 351 inode = hypfs_make_inode(sb, mode); 352 if (!inode) { 353 dput(dentry); 354 dentry = ERR_PTR(-ENOMEM); 355 goto fail; 356 } 357 if (mode & S_IFREG) { 358 inode->i_fop = &hypfs_file_ops; 359 if (data) 360 inode->i_size = strlen(data); 361 else 362 inode->i_size = 0; 363 } else if (mode & S_IFDIR) { 364 inode->i_op = &simple_dir_inode_operations; 365 inode->i_fop = &simple_dir_operations; 366 parent->d_inode->i_nlink++; 367 } else 368 BUG(); 369 inode->i_private = data; 370 d_instantiate(dentry, inode); 371 dget(dentry); 372 fail: 373 mutex_unlock(&parent->d_inode->i_mutex); 374 return dentry; 375 } 376 377 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent, 378 const char *name) 379 { 380 struct dentry *dentry; 381 382 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE); 383 if (IS_ERR(dentry)) 384 return dentry; 385 hypfs_add_dentry(dentry); 386 return dentry; 387 } 388 389 static struct dentry *hypfs_create_update_file(struct super_block *sb, 390 struct dentry *dir) 391 { 392 struct dentry *dentry; 393 394 dentry = hypfs_create_file(sb, dir, "update", NULL, 395 S_IFREG | UPDATE_FILE_MODE); 396 /* 397 * We do not put the update file on the 'delete' list with 398 * hypfs_add_dentry(), since it should not be removed when the tree 399 * is updated. 400 */ 401 return dentry; 402 } 403 404 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir, 405 const char *name, __u64 value) 406 { 407 char *buffer; 408 char tmp[TMP_SIZE]; 409 struct dentry *dentry; 410 411 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value); 412 buffer = kstrdup(tmp, GFP_KERNEL); 413 if (!buffer) 414 return ERR_PTR(-ENOMEM); 415 dentry = 416 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 417 if (IS_ERR(dentry)) { 418 kfree(buffer); 419 return ERR_PTR(-ENOMEM); 420 } 421 hypfs_add_dentry(dentry); 422 return dentry; 423 } 424 425 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir, 426 const char *name, char *string) 427 { 428 char *buffer; 429 struct dentry *dentry; 430 431 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); 432 if (!buffer) 433 return ERR_PTR(-ENOMEM); 434 sprintf(buffer, "%s\n", string); 435 dentry = 436 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 437 if (IS_ERR(dentry)) { 438 kfree(buffer); 439 return ERR_PTR(-ENOMEM); 440 } 441 hypfs_add_dentry(dentry); 442 return dentry; 443 } 444 445 static const struct file_operations hypfs_file_ops = { 446 .open = hypfs_open, 447 .release = hypfs_release, 448 .read = do_sync_read, 449 .write = do_sync_write, 450 .aio_read = hypfs_aio_read, 451 .aio_write = hypfs_aio_write, 452 .llseek = no_llseek, 453 }; 454 455 static struct file_system_type hypfs_type = { 456 .owner = THIS_MODULE, 457 .name = "s390_hypfs", 458 .mount = hypfs_mount, 459 .kill_sb = hypfs_kill_super 460 }; 461 462 static const struct super_operations hypfs_s_ops = { 463 .statfs = simple_statfs, 464 .evict_inode = hypfs_evict_inode, 465 .show_options = hypfs_show_options, 466 }; 467 468 static struct kobject *s390_kobj; 469 470 static int __init hypfs_init(void) 471 { 472 int rc; 473 474 hypfs_dbfs_dir = debugfs_create_dir("s390_hypfs", NULL); 475 if (IS_ERR(hypfs_dbfs_dir)) 476 return PTR_ERR(hypfs_dbfs_dir); 477 478 if (hypfs_diag_init()) { 479 rc = -ENODATA; 480 goto fail_debugfs_remove; 481 } 482 if (hypfs_vm_init()) { 483 rc = -ENODATA; 484 goto fail_hypfs_diag_exit; 485 } 486 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj); 487 if (!s390_kobj) { 488 rc = -ENOMEM; 489 goto fail_hypfs_vm_exit; 490 } 491 rc = register_filesystem(&hypfs_type); 492 if (rc) 493 goto fail_filesystem; 494 return 0; 495 496 fail_filesystem: 497 kobject_put(s390_kobj); 498 fail_hypfs_vm_exit: 499 hypfs_vm_exit(); 500 fail_hypfs_diag_exit: 501 hypfs_diag_exit(); 502 fail_debugfs_remove: 503 debugfs_remove(hypfs_dbfs_dir); 504 505 pr_err("Initialization of hypfs failed with rc=%i\n", rc); 506 return rc; 507 } 508 509 static void __exit hypfs_exit(void) 510 { 511 hypfs_diag_exit(); 512 hypfs_vm_exit(); 513 debugfs_remove(hypfs_dbfs_dir); 514 unregister_filesystem(&hypfs_type); 515 kobject_put(s390_kobj); 516 } 517 518 module_init(hypfs_init) 519 module_exit(hypfs_exit) 520 521 MODULE_LICENSE("GPL"); 522 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>"); 523 MODULE_DESCRIPTION("s390 Hypervisor Filesystem"); 524