1 /* -*- mode: c; c-basic-offset: 8; -*- 2 * vim: noexpandtab sw=8 ts=8 sts=0: 3 * 4 * dlmfs.c 5 * 6 * Code which implements the kernel side of a minimal userspace 7 * interface to our DLM. This file handles the virtual file system 8 * used for communication with userspace. Credit should go to ramfs, 9 * which was a template for the fs side of this module. 10 * 11 * Copyright (C) 2003, 2004 Oracle. All rights reserved. 12 * 13 * This program is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU General Public 15 * License as published by the Free Software Foundation; either 16 * version 2 of the License, or (at your option) any later version. 17 * 18 * This program is distributed in the hope that it will be useful, 19 * but WITHOUT ANY WARRANTY; without even the implied warranty of 20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 21 * General Public License for more details. 22 * 23 * You should have received a copy of the GNU General Public 24 * License along with this program; if not, write to the 25 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 26 * Boston, MA 021110-1307, USA. 27 */ 28 29 /* Simple VFS hooks based on: */ 30 /* 31 * Resizable simple ram filesystem for Linux. 32 * 33 * Copyright (C) 2000 Linus Torvalds. 34 * 2000 Transmeta Corp. 35 */ 36 37 #include <linux/module.h> 38 #include <linux/fs.h> 39 #include <linux/pagemap.h> 40 #include <linux/types.h> 41 #include <linux/slab.h> 42 #include <linux/highmem.h> 43 #include <linux/init.h> 44 #include <linux/string.h> 45 #include <linux/backing-dev.h> 46 #include <linux/poll.h> 47 48 #include <linux/uaccess.h> 49 50 #include "stackglue.h" 51 #include "userdlm.h" 52 53 #define MLOG_MASK_PREFIX ML_DLMFS 54 #include "cluster/masklog.h" 55 56 57 static const struct super_operations dlmfs_ops; 58 static const struct file_operations dlmfs_file_operations; 59 static const struct inode_operations dlmfs_dir_inode_operations; 60 static const struct inode_operations dlmfs_root_inode_operations; 61 static const struct inode_operations dlmfs_file_inode_operations; 62 static struct kmem_cache *dlmfs_inode_cache; 63 64 struct workqueue_struct *user_dlm_worker; 65 66 67 68 /* 69 * These are the ABI capabilities of dlmfs. 70 * 71 * Over time, dlmfs has added some features that were not part of the 72 * initial ABI. Unfortunately, some of these features are not detectable 73 * via standard usage. For example, Linux's default poll always returns 74 * POLLIN, so there is no way for a caller of poll(2) to know when dlmfs 75 * added poll support. Instead, we provide this list of new capabilities. 76 * 77 * Capabilities is a read-only attribute. We do it as a module parameter 78 * so we can discover it whether dlmfs is built in, loaded, or even not 79 * loaded. 80 * 81 * The ABI features are local to this machine's dlmfs mount. This is 82 * distinct from the locking protocol, which is concerned with inter-node 83 * interaction. 84 * 85 * Capabilities: 86 * - bast : POLLIN against the file descriptor of a held lock 87 * signifies a bast fired on the lock. 88 */ 89 #define DLMFS_CAPABILITIES "bast stackglue" 90 static int param_set_dlmfs_capabilities(const char *val, 91 struct kernel_param *kp) 92 { 93 printk(KERN_ERR "%s: readonly parameter\n", kp->name); 94 return -EINVAL; 95 } 96 static int param_get_dlmfs_capabilities(char *buffer, 97 struct kernel_param *kp) 98 { 99 return strlcpy(buffer, DLMFS_CAPABILITIES, 100 strlen(DLMFS_CAPABILITIES) + 1); 101 } 102 module_param_call(capabilities, param_set_dlmfs_capabilities, 103 param_get_dlmfs_capabilities, NULL, 0444); 104 MODULE_PARM_DESC(capabilities, DLMFS_CAPABILITIES); 105 106 107 /* 108 * decodes a set of open flags into a valid lock level and a set of flags. 109 * returns < 0 if we have invalid flags 110 * flags which mean something to us: 111 * O_RDONLY -> PRMODE level 112 * O_WRONLY -> EXMODE level 113 * 114 * O_NONBLOCK -> NOQUEUE 115 */ 116 static int dlmfs_decode_open_flags(int open_flags, 117 int *level, 118 int *flags) 119 { 120 if (open_flags & (O_WRONLY|O_RDWR)) 121 *level = DLM_LOCK_EX; 122 else 123 *level = DLM_LOCK_PR; 124 125 *flags = 0; 126 if (open_flags & O_NONBLOCK) 127 *flags |= DLM_LKF_NOQUEUE; 128 129 return 0; 130 } 131 132 static int dlmfs_file_open(struct inode *inode, 133 struct file *file) 134 { 135 int status, level, flags; 136 struct dlmfs_filp_private *fp = NULL; 137 struct dlmfs_inode_private *ip; 138 139 if (S_ISDIR(inode->i_mode)) 140 BUG(); 141 142 mlog(0, "open called on inode %lu, flags 0x%x\n", inode->i_ino, 143 file->f_flags); 144 145 status = dlmfs_decode_open_flags(file->f_flags, &level, &flags); 146 if (status < 0) 147 goto bail; 148 149 /* We don't want to honor O_APPEND at read/write time as it 150 * doesn't make sense for LVB writes. */ 151 file->f_flags &= ~O_APPEND; 152 153 fp = kmalloc(sizeof(*fp), GFP_NOFS); 154 if (!fp) { 155 status = -ENOMEM; 156 goto bail; 157 } 158 fp->fp_lock_level = level; 159 160 ip = DLMFS_I(inode); 161 162 status = user_dlm_cluster_lock(&ip->ip_lockres, level, flags); 163 if (status < 0) { 164 /* this is a strange error to return here but I want 165 * to be able userspace to be able to distinguish a 166 * valid lock request from one that simply couldn't be 167 * granted. */ 168 if (flags & DLM_LKF_NOQUEUE && status == -EAGAIN) 169 status = -ETXTBSY; 170 kfree(fp); 171 goto bail; 172 } 173 174 file->private_data = fp; 175 bail: 176 return status; 177 } 178 179 static int dlmfs_file_release(struct inode *inode, 180 struct file *file) 181 { 182 int level, status; 183 struct dlmfs_inode_private *ip = DLMFS_I(inode); 184 struct dlmfs_filp_private *fp = file->private_data; 185 186 if (S_ISDIR(inode->i_mode)) 187 BUG(); 188 189 mlog(0, "close called on inode %lu\n", inode->i_ino); 190 191 status = 0; 192 if (fp) { 193 level = fp->fp_lock_level; 194 if (level != DLM_LOCK_IV) 195 user_dlm_cluster_unlock(&ip->ip_lockres, level); 196 197 kfree(fp); 198 file->private_data = NULL; 199 } 200 201 return 0; 202 } 203 204 /* 205 * We do ->setattr() just to override size changes. Our size is the size 206 * of the LVB and nothing else. 207 */ 208 static int dlmfs_file_setattr(struct dentry *dentry, struct iattr *attr) 209 { 210 int error; 211 struct inode *inode = d_inode(dentry); 212 213 attr->ia_valid &= ~ATTR_SIZE; 214 error = setattr_prepare(dentry, attr); 215 if (error) 216 return error; 217 218 setattr_copy(inode, attr); 219 mark_inode_dirty(inode); 220 return 0; 221 } 222 223 static unsigned int dlmfs_file_poll(struct file *file, poll_table *wait) 224 { 225 int event = 0; 226 struct inode *inode = file_inode(file); 227 struct dlmfs_inode_private *ip = DLMFS_I(inode); 228 229 poll_wait(file, &ip->ip_lockres.l_event, wait); 230 231 spin_lock(&ip->ip_lockres.l_lock); 232 if (ip->ip_lockres.l_flags & USER_LOCK_BLOCKED) 233 event = POLLIN | POLLRDNORM; 234 spin_unlock(&ip->ip_lockres.l_lock); 235 236 return event; 237 } 238 239 static ssize_t dlmfs_file_read(struct file *filp, 240 char __user *buf, 241 size_t count, 242 loff_t *ppos) 243 { 244 int bytes_left; 245 ssize_t readlen, got; 246 char *lvb_buf; 247 struct inode *inode = file_inode(filp); 248 249 mlog(0, "inode %lu, count = %zu, *ppos = %llu\n", 250 inode->i_ino, count, *ppos); 251 252 if (*ppos >= i_size_read(inode)) 253 return 0; 254 255 if (!count) 256 return 0; 257 258 if (!access_ok(VERIFY_WRITE, buf, count)) 259 return -EFAULT; 260 261 /* don't read past the lvb */ 262 if ((count + *ppos) > i_size_read(inode)) 263 readlen = i_size_read(inode) - *ppos; 264 else 265 readlen = count; 266 267 lvb_buf = kmalloc(readlen, GFP_NOFS); 268 if (!lvb_buf) 269 return -ENOMEM; 270 271 got = user_dlm_read_lvb(inode, lvb_buf, readlen); 272 if (got) { 273 BUG_ON(got != readlen); 274 bytes_left = __copy_to_user(buf, lvb_buf, readlen); 275 readlen -= bytes_left; 276 } else 277 readlen = 0; 278 279 kfree(lvb_buf); 280 281 *ppos = *ppos + readlen; 282 283 mlog(0, "read %zd bytes\n", readlen); 284 return readlen; 285 } 286 287 static ssize_t dlmfs_file_write(struct file *filp, 288 const char __user *buf, 289 size_t count, 290 loff_t *ppos) 291 { 292 int bytes_left; 293 ssize_t writelen; 294 char *lvb_buf; 295 struct inode *inode = file_inode(filp); 296 297 mlog(0, "inode %lu, count = %zu, *ppos = %llu\n", 298 inode->i_ino, count, *ppos); 299 300 if (*ppos >= i_size_read(inode)) 301 return -ENOSPC; 302 303 if (!count) 304 return 0; 305 306 if (!access_ok(VERIFY_READ, buf, count)) 307 return -EFAULT; 308 309 /* don't write past the lvb */ 310 if ((count + *ppos) > i_size_read(inode)) 311 writelen = i_size_read(inode) - *ppos; 312 else 313 writelen = count - *ppos; 314 315 lvb_buf = kmalloc(writelen, GFP_NOFS); 316 if (!lvb_buf) 317 return -ENOMEM; 318 319 bytes_left = copy_from_user(lvb_buf, buf, writelen); 320 writelen -= bytes_left; 321 if (writelen) 322 user_dlm_write_lvb(inode, lvb_buf, writelen); 323 324 kfree(lvb_buf); 325 326 *ppos = *ppos + writelen; 327 mlog(0, "wrote %zd bytes\n", writelen); 328 return writelen; 329 } 330 331 static void dlmfs_init_once(void *foo) 332 { 333 struct dlmfs_inode_private *ip = 334 (struct dlmfs_inode_private *) foo; 335 336 ip->ip_conn = NULL; 337 ip->ip_parent = NULL; 338 339 inode_init_once(&ip->ip_vfs_inode); 340 } 341 342 static struct inode *dlmfs_alloc_inode(struct super_block *sb) 343 { 344 struct dlmfs_inode_private *ip; 345 346 ip = kmem_cache_alloc(dlmfs_inode_cache, GFP_NOFS); 347 if (!ip) 348 return NULL; 349 350 return &ip->ip_vfs_inode; 351 } 352 353 static void dlmfs_i_callback(struct rcu_head *head) 354 { 355 struct inode *inode = container_of(head, struct inode, i_rcu); 356 kmem_cache_free(dlmfs_inode_cache, DLMFS_I(inode)); 357 } 358 359 static void dlmfs_destroy_inode(struct inode *inode) 360 { 361 call_rcu(&inode->i_rcu, dlmfs_i_callback); 362 } 363 364 static void dlmfs_evict_inode(struct inode *inode) 365 { 366 int status; 367 struct dlmfs_inode_private *ip; 368 369 clear_inode(inode); 370 371 mlog(0, "inode %lu\n", inode->i_ino); 372 373 ip = DLMFS_I(inode); 374 375 if (S_ISREG(inode->i_mode)) { 376 status = user_dlm_destroy_lock(&ip->ip_lockres); 377 if (status < 0) 378 mlog_errno(status); 379 iput(ip->ip_parent); 380 goto clear_fields; 381 } 382 383 mlog(0, "we're a directory, ip->ip_conn = 0x%p\n", ip->ip_conn); 384 /* we must be a directory. If required, lets unregister the 385 * dlm context now. */ 386 if (ip->ip_conn) 387 user_dlm_unregister(ip->ip_conn); 388 clear_fields: 389 ip->ip_parent = NULL; 390 ip->ip_conn = NULL; 391 } 392 393 static struct inode *dlmfs_get_root_inode(struct super_block *sb) 394 { 395 struct inode *inode = new_inode(sb); 396 umode_t mode = S_IFDIR | 0755; 397 398 if (inode) { 399 inode->i_ino = get_next_ino(); 400 inode_init_owner(inode, NULL, mode); 401 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); 402 inc_nlink(inode); 403 404 inode->i_fop = &simple_dir_operations; 405 inode->i_op = &dlmfs_root_inode_operations; 406 } 407 408 return inode; 409 } 410 411 static struct inode *dlmfs_get_inode(struct inode *parent, 412 struct dentry *dentry, 413 umode_t mode) 414 { 415 struct super_block *sb = parent->i_sb; 416 struct inode * inode = new_inode(sb); 417 struct dlmfs_inode_private *ip; 418 419 if (!inode) 420 return NULL; 421 422 inode->i_ino = get_next_ino(); 423 inode_init_owner(inode, parent, mode); 424 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); 425 426 ip = DLMFS_I(inode); 427 ip->ip_conn = DLMFS_I(parent)->ip_conn; 428 429 switch (mode & S_IFMT) { 430 default: 431 /* for now we don't support anything other than 432 * directories and regular files. */ 433 BUG(); 434 break; 435 case S_IFREG: 436 inode->i_op = &dlmfs_file_inode_operations; 437 inode->i_fop = &dlmfs_file_operations; 438 439 i_size_write(inode, DLM_LVB_LEN); 440 441 user_dlm_lock_res_init(&ip->ip_lockres, dentry); 442 443 /* released at clear_inode time, this insures that we 444 * get to drop the dlm reference on each lock *before* 445 * we call the unregister code for releasing parent 446 * directories. */ 447 ip->ip_parent = igrab(parent); 448 BUG_ON(!ip->ip_parent); 449 break; 450 case S_IFDIR: 451 inode->i_op = &dlmfs_dir_inode_operations; 452 inode->i_fop = &simple_dir_operations; 453 454 /* directory inodes start off with i_nlink == 455 * 2 (for "." entry) */ 456 inc_nlink(inode); 457 break; 458 } 459 return inode; 460 } 461 462 /* 463 * File creation. Allocate an inode, and we're done.. 464 */ 465 /* SMP-safe */ 466 static int dlmfs_mkdir(struct inode * dir, 467 struct dentry * dentry, 468 umode_t mode) 469 { 470 int status; 471 struct inode *inode = NULL; 472 const struct qstr *domain = &dentry->d_name; 473 struct dlmfs_inode_private *ip; 474 struct ocfs2_cluster_connection *conn; 475 476 mlog(0, "mkdir %.*s\n", domain->len, domain->name); 477 478 /* verify that we have a proper domain */ 479 if (domain->len >= GROUP_NAME_MAX) { 480 status = -EINVAL; 481 mlog(ML_ERROR, "invalid domain name for directory.\n"); 482 goto bail; 483 } 484 485 inode = dlmfs_get_inode(dir, dentry, mode | S_IFDIR); 486 if (!inode) { 487 status = -ENOMEM; 488 mlog_errno(status); 489 goto bail; 490 } 491 492 ip = DLMFS_I(inode); 493 494 conn = user_dlm_register(domain); 495 if (IS_ERR(conn)) { 496 status = PTR_ERR(conn); 497 mlog(ML_ERROR, "Error %d could not register domain \"%.*s\"\n", 498 status, domain->len, domain->name); 499 goto bail; 500 } 501 ip->ip_conn = conn; 502 503 inc_nlink(dir); 504 d_instantiate(dentry, inode); 505 dget(dentry); /* Extra count - pin the dentry in core */ 506 507 status = 0; 508 bail: 509 if (status < 0) 510 iput(inode); 511 return status; 512 } 513 514 static int dlmfs_create(struct inode *dir, 515 struct dentry *dentry, 516 umode_t mode, 517 bool excl) 518 { 519 int status = 0; 520 struct inode *inode; 521 const struct qstr *name = &dentry->d_name; 522 523 mlog(0, "create %.*s\n", name->len, name->name); 524 525 /* verify name is valid and doesn't contain any dlm reserved 526 * characters */ 527 if (name->len >= USER_DLM_LOCK_ID_MAX_LEN || 528 name->name[0] == '$') { 529 status = -EINVAL; 530 mlog(ML_ERROR, "invalid lock name, %.*s\n", name->len, 531 name->name); 532 goto bail; 533 } 534 535 inode = dlmfs_get_inode(dir, dentry, mode | S_IFREG); 536 if (!inode) { 537 status = -ENOMEM; 538 mlog_errno(status); 539 goto bail; 540 } 541 542 d_instantiate(dentry, inode); 543 dget(dentry); /* Extra count - pin the dentry in core */ 544 bail: 545 return status; 546 } 547 548 static int dlmfs_unlink(struct inode *dir, 549 struct dentry *dentry) 550 { 551 int status; 552 struct inode *inode = d_inode(dentry); 553 554 mlog(0, "unlink inode %lu\n", inode->i_ino); 555 556 /* if there are no current holders, or none that are waiting 557 * to acquire a lock, this basically destroys our lockres. */ 558 status = user_dlm_destroy_lock(&DLMFS_I(inode)->ip_lockres); 559 if (status < 0) { 560 mlog(ML_ERROR, "unlink %pd, error %d from destroy\n", 561 dentry, status); 562 goto bail; 563 } 564 status = simple_unlink(dir, dentry); 565 bail: 566 return status; 567 } 568 569 static int dlmfs_fill_super(struct super_block * sb, 570 void * data, 571 int silent) 572 { 573 sb->s_maxbytes = MAX_LFS_FILESIZE; 574 sb->s_blocksize = PAGE_SIZE; 575 sb->s_blocksize_bits = PAGE_SHIFT; 576 sb->s_magic = DLMFS_MAGIC; 577 sb->s_op = &dlmfs_ops; 578 sb->s_root = d_make_root(dlmfs_get_root_inode(sb)); 579 if (!sb->s_root) 580 return -ENOMEM; 581 return 0; 582 } 583 584 static const struct file_operations dlmfs_file_operations = { 585 .open = dlmfs_file_open, 586 .release = dlmfs_file_release, 587 .poll = dlmfs_file_poll, 588 .read = dlmfs_file_read, 589 .write = dlmfs_file_write, 590 .llseek = default_llseek, 591 }; 592 593 static const struct inode_operations dlmfs_dir_inode_operations = { 594 .create = dlmfs_create, 595 .lookup = simple_lookup, 596 .unlink = dlmfs_unlink, 597 }; 598 599 /* this way we can restrict mkdir to only the toplevel of the fs. */ 600 static const struct inode_operations dlmfs_root_inode_operations = { 601 .lookup = simple_lookup, 602 .mkdir = dlmfs_mkdir, 603 .rmdir = simple_rmdir, 604 }; 605 606 static const struct super_operations dlmfs_ops = { 607 .statfs = simple_statfs, 608 .alloc_inode = dlmfs_alloc_inode, 609 .destroy_inode = dlmfs_destroy_inode, 610 .evict_inode = dlmfs_evict_inode, 611 .drop_inode = generic_delete_inode, 612 }; 613 614 static const struct inode_operations dlmfs_file_inode_operations = { 615 .getattr = simple_getattr, 616 .setattr = dlmfs_file_setattr, 617 }; 618 619 static struct dentry *dlmfs_mount(struct file_system_type *fs_type, 620 int flags, const char *dev_name, void *data) 621 { 622 return mount_nodev(fs_type, flags, data, dlmfs_fill_super); 623 } 624 625 static struct file_system_type dlmfs_fs_type = { 626 .owner = THIS_MODULE, 627 .name = "ocfs2_dlmfs", 628 .mount = dlmfs_mount, 629 .kill_sb = kill_litter_super, 630 }; 631 MODULE_ALIAS_FS("ocfs2_dlmfs"); 632 633 static int __init init_dlmfs_fs(void) 634 { 635 int status; 636 int cleanup_inode = 0, cleanup_worker = 0; 637 638 dlmfs_inode_cache = kmem_cache_create("dlmfs_inode_cache", 639 sizeof(struct dlmfs_inode_private), 640 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 641 SLAB_MEM_SPREAD|SLAB_ACCOUNT), 642 dlmfs_init_once); 643 if (!dlmfs_inode_cache) { 644 status = -ENOMEM; 645 goto bail; 646 } 647 cleanup_inode = 1; 648 649 user_dlm_worker = alloc_workqueue("user_dlm", WQ_MEM_RECLAIM, 0); 650 if (!user_dlm_worker) { 651 status = -ENOMEM; 652 goto bail; 653 } 654 cleanup_worker = 1; 655 656 user_dlm_set_locking_protocol(); 657 status = register_filesystem(&dlmfs_fs_type); 658 bail: 659 if (status) { 660 if (cleanup_inode) 661 kmem_cache_destroy(dlmfs_inode_cache); 662 if (cleanup_worker) 663 destroy_workqueue(user_dlm_worker); 664 } else 665 printk("OCFS2 User DLM kernel interface loaded\n"); 666 return status; 667 } 668 669 static void __exit exit_dlmfs_fs(void) 670 { 671 unregister_filesystem(&dlmfs_fs_type); 672 673 flush_workqueue(user_dlm_worker); 674 destroy_workqueue(user_dlm_worker); 675 676 /* 677 * Make sure all delayed rcu free inodes are flushed before we 678 * destroy cache. 679 */ 680 rcu_barrier(); 681 kmem_cache_destroy(dlmfs_inode_cache); 682 683 } 684 685 MODULE_AUTHOR("Oracle"); 686 MODULE_LICENSE("GPL"); 687 MODULE_DESCRIPTION("OCFS2 DLM-Filesystem"); 688 689 module_init(init_dlmfs_fs) 690 module_exit(exit_dlmfs_fs) 691