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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
57static const struct super_operations dlmfs_ops;
58static const struct file_operations dlmfs_file_operations;
59static const struct inode_operations dlmfs_dir_inode_operations;
60static const struct inode_operations dlmfs_root_inode_operations;
61static const struct inode_operations dlmfs_file_inode_operations;
62static struct kmem_cache *dlmfs_inode_cache;
63
64struct 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"
90static 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}
96static 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}
102module_param_call(capabilities, param_set_dlmfs_capabilities,
103 param_get_dlmfs_capabilities, NULL, 0444);
104MODULE_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 */
116static 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
132static 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;
175bail:
176 return status;
177}
178
179static 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 */
208static 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
223static 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
239static 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
287static 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
331static 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
342static 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
353static 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
359static void dlmfs_destroy_inode(struct inode *inode)
360{
361 call_rcu(&inode->i_rcu, dlmfs_i_callback);
362}
363
364static 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);
388clear_fields:
389 ip->ip_parent = NULL;
390 ip->ip_conn = NULL;
391}
392
393static 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
411static 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 */
466static 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;
508bail:
509 if (status < 0)
510 iput(inode);
511 return status;
512}
513
514static 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 */
544bail:
545 return status;
546}
547
548static 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);
565bail:
566 return status;
567}
568
569static 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
584static 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
593static 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. */
600static const struct inode_operations dlmfs_root_inode_operations = {
601 .lookup = simple_lookup,
602 .mkdir = dlmfs_mkdir,
603 .rmdir = simple_rmdir,
604};
605
606static 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
614static const struct inode_operations dlmfs_file_inode_operations = {
615 .getattr = simple_getattr,
616 .setattr = dlmfs_file_setattr,
617};
618
619static 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
625static 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};
631MODULE_ALIAS_FS("ocfs2_dlmfs");
632
633static 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);
658bail:
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
669static 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
685MODULE_AUTHOR("Oracle");
686MODULE_LICENSE("GPL");
687MODULE_DESCRIPTION("OCFS2 DLM-Filesystem");
688
689module_init(init_dlmfs_fs)
690module_exit(exit_dlmfs_fs)
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 <asm/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
57static const struct super_operations dlmfs_ops;
58static const struct file_operations dlmfs_file_operations;
59static const struct inode_operations dlmfs_dir_inode_operations;
60static const struct inode_operations dlmfs_root_inode_operations;
61static const struct inode_operations dlmfs_file_inode_operations;
62static struct kmem_cache *dlmfs_inode_cache;
63
64struct 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"
90static 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}
96static 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}
102module_param_call(capabilities, param_set_dlmfs_capabilities,
103 param_get_dlmfs_capabilities, NULL, 0444);
104MODULE_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 */
116static 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
132static 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;
175bail:
176 return status;
177}
178
179static 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 */
208static int dlmfs_file_setattr(struct dentry *dentry, struct iattr *attr)
209{
210 int error;
211 struct inode *inode = dentry->d_inode;
212
213 attr->ia_valid &= ~ATTR_SIZE;
214 error = inode_change_ok(inode, attr);
215 if (error)
216 return error;
217
218 setattr_copy(inode, attr);
219 mark_inode_dirty(inode);
220 return 0;
221}
222
223static 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
239static 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
287static 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
331static 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
342static 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
353static 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
359static void dlmfs_destroy_inode(struct inode *inode)
360{
361 call_rcu(&inode->i_rcu, dlmfs_i_callback);
362}
363
364static 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);
388clear_fields:
389 ip->ip_parent = NULL;
390 ip->ip_conn = NULL;
391}
392
393static struct backing_dev_info dlmfs_backing_dev_info = {
394 .name = "ocfs2-dlmfs",
395 .ra_pages = 0, /* No readahead */
396 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
397};
398
399static struct inode *dlmfs_get_root_inode(struct super_block *sb)
400{
401 struct inode *inode = new_inode(sb);
402 umode_t mode = S_IFDIR | 0755;
403
404 if (inode) {
405 inode->i_ino = get_next_ino();
406 inode_init_owner(inode, NULL, mode);
407 inode->i_mapping->backing_dev_info = &dlmfs_backing_dev_info;
408 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
409 inc_nlink(inode);
410
411 inode->i_fop = &simple_dir_operations;
412 inode->i_op = &dlmfs_root_inode_operations;
413 }
414
415 return inode;
416}
417
418static struct inode *dlmfs_get_inode(struct inode *parent,
419 struct dentry *dentry,
420 umode_t mode)
421{
422 struct super_block *sb = parent->i_sb;
423 struct inode * inode = new_inode(sb);
424 struct dlmfs_inode_private *ip;
425
426 if (!inode)
427 return NULL;
428
429 inode->i_ino = get_next_ino();
430 inode_init_owner(inode, parent, mode);
431 inode->i_mapping->backing_dev_info = &dlmfs_backing_dev_info;
432 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
433
434 ip = DLMFS_I(inode);
435 ip->ip_conn = DLMFS_I(parent)->ip_conn;
436
437 switch (mode & S_IFMT) {
438 default:
439 /* for now we don't support anything other than
440 * directories and regular files. */
441 BUG();
442 break;
443 case S_IFREG:
444 inode->i_op = &dlmfs_file_inode_operations;
445 inode->i_fop = &dlmfs_file_operations;
446
447 i_size_write(inode, DLM_LVB_LEN);
448
449 user_dlm_lock_res_init(&ip->ip_lockres, dentry);
450
451 /* released at clear_inode time, this insures that we
452 * get to drop the dlm reference on each lock *before*
453 * we call the unregister code for releasing parent
454 * directories. */
455 ip->ip_parent = igrab(parent);
456 BUG_ON(!ip->ip_parent);
457 break;
458 case S_IFDIR:
459 inode->i_op = &dlmfs_dir_inode_operations;
460 inode->i_fop = &simple_dir_operations;
461
462 /* directory inodes start off with i_nlink ==
463 * 2 (for "." entry) */
464 inc_nlink(inode);
465 break;
466 }
467 return inode;
468}
469
470/*
471 * File creation. Allocate an inode, and we're done..
472 */
473/* SMP-safe */
474static int dlmfs_mkdir(struct inode * dir,
475 struct dentry * dentry,
476 umode_t mode)
477{
478 int status;
479 struct inode *inode = NULL;
480 struct qstr *domain = &dentry->d_name;
481 struct dlmfs_inode_private *ip;
482 struct ocfs2_cluster_connection *conn;
483
484 mlog(0, "mkdir %.*s\n", domain->len, domain->name);
485
486 /* verify that we have a proper domain */
487 if (domain->len >= GROUP_NAME_MAX) {
488 status = -EINVAL;
489 mlog(ML_ERROR, "invalid domain name for directory.\n");
490 goto bail;
491 }
492
493 inode = dlmfs_get_inode(dir, dentry, mode | S_IFDIR);
494 if (!inode) {
495 status = -ENOMEM;
496 mlog_errno(status);
497 goto bail;
498 }
499
500 ip = DLMFS_I(inode);
501
502 conn = user_dlm_register(domain);
503 if (IS_ERR(conn)) {
504 status = PTR_ERR(conn);
505 mlog(ML_ERROR, "Error %d could not register domain \"%.*s\"\n",
506 status, domain->len, domain->name);
507 goto bail;
508 }
509 ip->ip_conn = conn;
510
511 inc_nlink(dir);
512 d_instantiate(dentry, inode);
513 dget(dentry); /* Extra count - pin the dentry in core */
514
515 status = 0;
516bail:
517 if (status < 0)
518 iput(inode);
519 return status;
520}
521
522static int dlmfs_create(struct inode *dir,
523 struct dentry *dentry,
524 umode_t mode,
525 bool excl)
526{
527 int status = 0;
528 struct inode *inode;
529 struct qstr *name = &dentry->d_name;
530
531 mlog(0, "create %.*s\n", name->len, name->name);
532
533 /* verify name is valid and doesn't contain any dlm reserved
534 * characters */
535 if (name->len >= USER_DLM_LOCK_ID_MAX_LEN ||
536 name->name[0] == '$') {
537 status = -EINVAL;
538 mlog(ML_ERROR, "invalid lock name, %.*s\n", name->len,
539 name->name);
540 goto bail;
541 }
542
543 inode = dlmfs_get_inode(dir, dentry, mode | S_IFREG);
544 if (!inode) {
545 status = -ENOMEM;
546 mlog_errno(status);
547 goto bail;
548 }
549
550 d_instantiate(dentry, inode);
551 dget(dentry); /* Extra count - pin the dentry in core */
552bail:
553 return status;
554}
555
556static int dlmfs_unlink(struct inode *dir,
557 struct dentry *dentry)
558{
559 int status;
560 struct inode *inode = dentry->d_inode;
561
562 mlog(0, "unlink inode %lu\n", inode->i_ino);
563
564 /* if there are no current holders, or none that are waiting
565 * to acquire a lock, this basically destroys our lockres. */
566 status = user_dlm_destroy_lock(&DLMFS_I(inode)->ip_lockres);
567 if (status < 0) {
568 mlog(ML_ERROR, "unlink %.*s, error %d from destroy\n",
569 dentry->d_name.len, dentry->d_name.name, status);
570 goto bail;
571 }
572 status = simple_unlink(dir, dentry);
573bail:
574 return status;
575}
576
577static int dlmfs_fill_super(struct super_block * sb,
578 void * data,
579 int silent)
580{
581 sb->s_maxbytes = MAX_LFS_FILESIZE;
582 sb->s_blocksize = PAGE_CACHE_SIZE;
583 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
584 sb->s_magic = DLMFS_MAGIC;
585 sb->s_op = &dlmfs_ops;
586 sb->s_root = d_make_root(dlmfs_get_root_inode(sb));
587 if (!sb->s_root)
588 return -ENOMEM;
589 return 0;
590}
591
592static const struct file_operations dlmfs_file_operations = {
593 .open = dlmfs_file_open,
594 .release = dlmfs_file_release,
595 .poll = dlmfs_file_poll,
596 .read = dlmfs_file_read,
597 .write = dlmfs_file_write,
598 .llseek = default_llseek,
599};
600
601static const struct inode_operations dlmfs_dir_inode_operations = {
602 .create = dlmfs_create,
603 .lookup = simple_lookup,
604 .unlink = dlmfs_unlink,
605};
606
607/* this way we can restrict mkdir to only the toplevel of the fs. */
608static const struct inode_operations dlmfs_root_inode_operations = {
609 .lookup = simple_lookup,
610 .mkdir = dlmfs_mkdir,
611 .rmdir = simple_rmdir,
612};
613
614static const struct super_operations dlmfs_ops = {
615 .statfs = simple_statfs,
616 .alloc_inode = dlmfs_alloc_inode,
617 .destroy_inode = dlmfs_destroy_inode,
618 .evict_inode = dlmfs_evict_inode,
619 .drop_inode = generic_delete_inode,
620};
621
622static const struct inode_operations dlmfs_file_inode_operations = {
623 .getattr = simple_getattr,
624 .setattr = dlmfs_file_setattr,
625};
626
627static struct dentry *dlmfs_mount(struct file_system_type *fs_type,
628 int flags, const char *dev_name, void *data)
629{
630 return mount_nodev(fs_type, flags, data, dlmfs_fill_super);
631}
632
633static struct file_system_type dlmfs_fs_type = {
634 .owner = THIS_MODULE,
635 .name = "ocfs2_dlmfs",
636 .mount = dlmfs_mount,
637 .kill_sb = kill_litter_super,
638};
639MODULE_ALIAS_FS("ocfs2_dlmfs");
640
641static int __init init_dlmfs_fs(void)
642{
643 int status;
644 int cleanup_inode = 0, cleanup_worker = 0;
645
646 status = bdi_init(&dlmfs_backing_dev_info);
647 if (status)
648 return status;
649
650 dlmfs_inode_cache = kmem_cache_create("dlmfs_inode_cache",
651 sizeof(struct dlmfs_inode_private),
652 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
653 SLAB_MEM_SPREAD),
654 dlmfs_init_once);
655 if (!dlmfs_inode_cache) {
656 status = -ENOMEM;
657 goto bail;
658 }
659 cleanup_inode = 1;
660
661 user_dlm_worker = create_singlethread_workqueue("user_dlm");
662 if (!user_dlm_worker) {
663 status = -ENOMEM;
664 goto bail;
665 }
666 cleanup_worker = 1;
667
668 user_dlm_set_locking_protocol();
669 status = register_filesystem(&dlmfs_fs_type);
670bail:
671 if (status) {
672 if (cleanup_inode)
673 kmem_cache_destroy(dlmfs_inode_cache);
674 if (cleanup_worker)
675 destroy_workqueue(user_dlm_worker);
676 bdi_destroy(&dlmfs_backing_dev_info);
677 } else
678 printk("OCFS2 User DLM kernel interface loaded\n");
679 return status;
680}
681
682static void __exit exit_dlmfs_fs(void)
683{
684 unregister_filesystem(&dlmfs_fs_type);
685
686 flush_workqueue(user_dlm_worker);
687 destroy_workqueue(user_dlm_worker);
688
689 /*
690 * Make sure all delayed rcu free inodes are flushed before we
691 * destroy cache.
692 */
693 rcu_barrier();
694 kmem_cache_destroy(dlmfs_inode_cache);
695
696 bdi_destroy(&dlmfs_backing_dev_info);
697}
698
699MODULE_AUTHOR("Oracle");
700MODULE_LICENSE("GPL");
701MODULE_DESCRIPTION("OCFS2 DLM-Filesystem");
702
703module_init(init_dlmfs_fs)
704module_exit(exit_dlmfs_fs)