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 31static struct dentry *hypfs_create_update_file(struct super_block *sb, 32 struct dentry *dir); 33 34struct 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 42static const struct file_operations hypfs_file_ops; 43static struct file_system_type hypfs_type; 44static const struct super_operations hypfs_s_ops; 45 46/* start of list of all dentries, which have to be deleted on update */ 47static struct dentry *hypfs_last_dentry; 48 49struct dentry *hypfs_dbfs_dir; 50 51static 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 62static void hypfs_add_dentry(struct dentry *dentry) 63{ 64 dentry->d_fsdata = hypfs_last_dentry; 65 hypfs_last_dentry = dentry; 66} 67 68static inline int hypfs_positive(struct dentry *dentry) 69{ 70 return dentry->d_inode && !d_unhashed(dentry); 71} 72 73static 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 92static 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 102static 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 120static void hypfs_evict_inode(struct inode *inode) 121{ 122 end_writeback(inode); 123 kfree(inode->i_private); 124} 125 126static 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 153static 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 char __user *buf = iov[0].iov_base; 160 size_t count = iov[0].iov_len; 161 162 if (nr_segs != 1) 163 return -EINVAL; 164 165 data = filp->private_data; 166 ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data)); 167 if (ret <= 0) 168 return ret; 169 170 iocb->ki_pos += ret; 171 file_accessed(filp); 172 173 return ret; 174} 175static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov, 176 unsigned long nr_segs, loff_t offset) 177{ 178 int rc; 179 struct super_block *sb; 180 struct hypfs_sb_info *fs_info; 181 size_t count = iov_length(iov, nr_segs); 182 183 sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb; 184 fs_info = sb->s_fs_info; 185 /* 186 * Currently we only allow one update per second for two reasons: 187 * 1. diag 204 is VERY expensive 188 * 2. If several processes do updates in parallel and then read the 189 * hypfs data, the likelihood of collisions is reduced, if we restrict 190 * the minimum update interval. A collision occurs, if during the 191 * data gathering of one process another process triggers an update 192 * If the first process wants to ensure consistent data, it has 193 * to restart data collection in this case. 194 */ 195 mutex_lock(&fs_info->lock); 196 if (fs_info->last_update == get_seconds()) { 197 rc = -EBUSY; 198 goto out; 199 } 200 hypfs_delete_tree(sb->s_root); 201 if (MACHINE_IS_VM) 202 rc = hypfs_vm_create_files(sb, sb->s_root); 203 else 204 rc = hypfs_diag_create_files(sb, sb->s_root); 205 if (rc) { 206 pr_err("Updating the hypfs tree failed\n"); 207 hypfs_delete_tree(sb->s_root); 208 goto out; 209 } 210 hypfs_update_update(sb); 211 rc = count; 212out: 213 mutex_unlock(&fs_info->lock); 214 return rc; 215} 216 217static int hypfs_release(struct inode *inode, struct file *filp) 218{ 219 kfree(filp->private_data); 220 return 0; 221} 222 223enum { opt_uid, opt_gid, opt_err }; 224 225static const match_table_t hypfs_tokens = { 226 {opt_uid, "uid=%u"}, 227 {opt_gid, "gid=%u"}, 228 {opt_err, NULL} 229}; 230 231static int hypfs_parse_options(char *options, struct super_block *sb) 232{ 233 char *str; 234 substring_t args[MAX_OPT_ARGS]; 235 236 if (!options) 237 return 0; 238 while ((str = strsep(&options, ",")) != NULL) { 239 int token, option; 240 struct hypfs_sb_info *hypfs_info = sb->s_fs_info; 241 242 if (!*str) 243 continue; 244 token = match_token(str, hypfs_tokens, args); 245 switch (token) { 246 case opt_uid: 247 if (match_int(&args[0], &option)) 248 return -EINVAL; 249 hypfs_info->uid = option; 250 break; 251 case opt_gid: 252 if (match_int(&args[0], &option)) 253 return -EINVAL; 254 hypfs_info->gid = option; 255 break; 256 case opt_err: 257 default: 258 pr_err("%s is not a valid mount option\n", str); 259 return -EINVAL; 260 } 261 } 262 return 0; 263} 264 265static int hypfs_show_options(struct seq_file *s, struct vfsmount *mnt) 266{ 267 struct hypfs_sb_info *hypfs_info = mnt->mnt_sb->s_fs_info; 268 269 seq_printf(s, ",uid=%u", hypfs_info->uid); 270 seq_printf(s, ",gid=%u", hypfs_info->gid); 271 return 0; 272} 273 274static int hypfs_fill_super(struct super_block *sb, void *data, int silent) 275{ 276 struct inode *root_inode; 277 struct dentry *root_dentry; 278 int rc = 0; 279 struct hypfs_sb_info *sbi; 280 281 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); 282 if (!sbi) 283 return -ENOMEM; 284 mutex_init(&sbi->lock); 285 sbi->uid = current_uid(); 286 sbi->gid = current_gid(); 287 sb->s_fs_info = sbi; 288 sb->s_blocksize = PAGE_CACHE_SIZE; 289 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 290 sb->s_magic = HYPFS_MAGIC; 291 sb->s_op = &hypfs_s_ops; 292 if (hypfs_parse_options(data, sb)) 293 return -EINVAL; 294 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755); 295 if (!root_inode) 296 return -ENOMEM; 297 root_inode->i_op = &simple_dir_inode_operations; 298 root_inode->i_fop = &simple_dir_operations; 299 sb->s_root = root_dentry = d_alloc_root(root_inode); 300 if (!root_dentry) { 301 iput(root_inode); 302 return -ENOMEM; 303 } 304 if (MACHINE_IS_VM) 305 rc = hypfs_vm_create_files(sb, root_dentry); 306 else 307 rc = hypfs_diag_create_files(sb, root_dentry); 308 if (rc) 309 return rc; 310 sbi->update_file = hypfs_create_update_file(sb, root_dentry); 311 if (IS_ERR(sbi->update_file)) 312 return PTR_ERR(sbi->update_file); 313 hypfs_update_update(sb); 314 pr_info("Hypervisor filesystem mounted\n"); 315 return 0; 316} 317 318static int hypfs_get_super(struct file_system_type *fst, int flags, 319 const char *devname, void *data, struct vfsmount *mnt) 320{ 321 return get_sb_single(fst, flags, data, hypfs_fill_super, mnt); 322} 323 324static void hypfs_kill_super(struct super_block *sb) 325{ 326 struct hypfs_sb_info *sb_info = sb->s_fs_info; 327 328 if (sb->s_root) 329 hypfs_delete_tree(sb->s_root); 330 if (sb_info->update_file) 331 hypfs_remove(sb_info->update_file); 332 kfree(sb->s_fs_info); 333 sb->s_fs_info = NULL; 334 kill_litter_super(sb); 335} 336 337static struct dentry *hypfs_create_file(struct super_block *sb, 338 struct dentry *parent, const char *name, 339 char *data, mode_t mode) 340{ 341 struct dentry *dentry; 342 struct inode *inode; 343 344 mutex_lock(&parent->d_inode->i_mutex); 345 dentry = lookup_one_len(name, parent, strlen(name)); 346 if (IS_ERR(dentry)) { 347 dentry = ERR_PTR(-ENOMEM); 348 goto fail; 349 } 350 inode = hypfs_make_inode(sb, mode); 351 if (!inode) { 352 dput(dentry); 353 dentry = ERR_PTR(-ENOMEM); 354 goto fail; 355 } 356 if (mode & S_IFREG) { 357 inode->i_fop = &hypfs_file_ops; 358 if (data) 359 inode->i_size = strlen(data); 360 else 361 inode->i_size = 0; 362 } else if (mode & S_IFDIR) { 363 inode->i_op = &simple_dir_inode_operations; 364 inode->i_fop = &simple_dir_operations; 365 parent->d_inode->i_nlink++; 366 } else 367 BUG(); 368 inode->i_private = data; 369 d_instantiate(dentry, inode); 370 dget(dentry); 371fail: 372 mutex_unlock(&parent->d_inode->i_mutex); 373 return dentry; 374} 375 376struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent, 377 const char *name) 378{ 379 struct dentry *dentry; 380 381 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE); 382 if (IS_ERR(dentry)) 383 return dentry; 384 hypfs_add_dentry(dentry); 385 return dentry; 386} 387 388static struct dentry *hypfs_create_update_file(struct super_block *sb, 389 struct dentry *dir) 390{ 391 struct dentry *dentry; 392 393 dentry = hypfs_create_file(sb, dir, "update", NULL, 394 S_IFREG | UPDATE_FILE_MODE); 395 /* 396 * We do not put the update file on the 'delete' list with 397 * hypfs_add_dentry(), since it should not be removed when the tree 398 * is updated. 399 */ 400 return dentry; 401} 402 403struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir, 404 const char *name, __u64 value) 405{ 406 char *buffer; 407 char tmp[TMP_SIZE]; 408 struct dentry *dentry; 409 410 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value); 411 buffer = kstrdup(tmp, GFP_KERNEL); 412 if (!buffer) 413 return ERR_PTR(-ENOMEM); 414 dentry = 415 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 416 if (IS_ERR(dentry)) { 417 kfree(buffer); 418 return ERR_PTR(-ENOMEM); 419 } 420 hypfs_add_dentry(dentry); 421 return dentry; 422} 423 424struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir, 425 const char *name, char *string) 426{ 427 char *buffer; 428 struct dentry *dentry; 429 430 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); 431 if (!buffer) 432 return ERR_PTR(-ENOMEM); 433 sprintf(buffer, "%s\n", string); 434 dentry = 435 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE); 436 if (IS_ERR(dentry)) { 437 kfree(buffer); 438 return ERR_PTR(-ENOMEM); 439 } 440 hypfs_add_dentry(dentry); 441 return dentry; 442} 443 444static const struct file_operations hypfs_file_ops = { 445 .open = hypfs_open, 446 .release = hypfs_release, 447 .read = do_sync_read, 448 .write = do_sync_write, 449 .aio_read = hypfs_aio_read, 450 .aio_write = hypfs_aio_write, 451}; 452 453static struct file_system_type hypfs_type = { 454 .owner = THIS_MODULE, 455 .name = "s390_hypfs", 456 .get_sb = hypfs_get_super, 457 .kill_sb = hypfs_kill_super 458}; 459 460static const struct super_operations hypfs_s_ops = { 461 .statfs = simple_statfs, 462 .evict_inode = hypfs_evict_inode, 463 .show_options = hypfs_show_options, 464}; 465 466static struct kobject *s390_kobj; 467 468static int __init hypfs_init(void) 469{ 470 int rc; 471 472 hypfs_dbfs_dir = debugfs_create_dir("s390_hypfs", NULL); 473 if (IS_ERR(hypfs_dbfs_dir)) 474 return PTR_ERR(hypfs_dbfs_dir); 475 476 if (hypfs_diag_init()) { 477 rc = -ENODATA; 478 goto fail_debugfs_remove; 479 } 480 if (hypfs_vm_init()) { 481 rc = -ENODATA; 482 goto fail_hypfs_diag_exit; 483 } 484 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj); 485 if (!s390_kobj) { 486 rc = -ENOMEM; 487 goto fail_hypfs_vm_exit; 488 } 489 rc = register_filesystem(&hypfs_type); 490 if (rc) 491 goto fail_filesystem; 492 return 0; 493 494fail_filesystem: 495 kobject_put(s390_kobj); 496fail_hypfs_vm_exit: 497 hypfs_vm_exit(); 498fail_hypfs_diag_exit: 499 hypfs_diag_exit(); 500fail_debugfs_remove: 501 debugfs_remove(hypfs_dbfs_dir); 502 503 pr_err("Initialization of hypfs failed with rc=%i\n", rc); 504 return rc; 505} 506 507static void __exit hypfs_exit(void) 508{ 509 hypfs_diag_exit(); 510 hypfs_vm_exit(); 511 debugfs_remove(hypfs_dbfs_dir); 512 unregister_filesystem(&hypfs_type); 513 kobject_put(s390_kobj); 514} 515 516module_init(hypfs_init) 517module_exit(hypfs_exit) 518 519MODULE_LICENSE("GPL"); 520MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>"); 521MODULE_DESCRIPTION("s390 Hypervisor Filesystem"); 522