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
47 #include <asm/uaccess.h>
48
49
50 #include "cluster/nodemanager.h"
51 #include "cluster/heartbeat.h"
52 #include "cluster/tcp.h"
53
54 #include "dlmapi.h"
55
56 #include "userdlm.h"
57
58 #include "dlmfsver.h"
59
60 #define MLOG_MASK_PREFIX ML_DLMFS
61 #include "cluster/masklog.h"
62
63 #include "ocfs2_lockingver.h"
64
65 static const struct super_operations dlmfs_ops;
66 static const struct file_operations dlmfs_file_operations;
67 static const struct inode_operations dlmfs_dir_inode_operations;
68 static const struct inode_operations dlmfs_root_inode_operations;
69 static const struct inode_operations dlmfs_file_inode_operations;
70 static struct kmem_cache *dlmfs_inode_cache;
71
72 struct workqueue_struct *user_dlm_worker;
73
74 /*
75 * This is the userdlmfs locking protocol version.
76 *
77 * See fs/ocfs2/dlmglue.c for more details on locking versions.
78 */
79 static const struct dlm_protocol_version user_locking_protocol = {
80 .pv_major = OCFS2_LOCKING_PROTOCOL_MAJOR,
81 .pv_minor = OCFS2_LOCKING_PROTOCOL_MINOR,
82 };
83
84 /*
85 * decodes a set of open flags into a valid lock level and a set of flags.
86 * returns < 0 if we have invalid flags
87 * flags which mean something to us:
88 * O_RDONLY -> PRMODE level
89 * O_WRONLY -> EXMODE level
90 *
91 * O_NONBLOCK -> LKM_NOQUEUE
92 */
93 static int dlmfs_decode_open_flags(int open_flags,
94 int *level,
95 int *flags)
96 {
97 if (open_flags & (O_WRONLY|O_RDWR))
98 *level = LKM_EXMODE;
99 else
100 *level = LKM_PRMODE;
101
102 *flags = 0;
103 if (open_flags & O_NONBLOCK)
104 *flags |= LKM_NOQUEUE;
105
106 return 0;
107 }
108
109 static int dlmfs_file_open(struct inode *inode,
110 struct file *file)
111 {
112 int status, level, flags;
113 struct dlmfs_filp_private *fp = NULL;
114 struct dlmfs_inode_private *ip;
115
116 if (S_ISDIR(inode->i_mode))
117 BUG();
118
119 mlog(0, "open called on inode %lu, flags 0x%x\n", inode->i_ino,
120 file->f_flags);
121
122 status = dlmfs_decode_open_flags(file->f_flags, &level, &flags);
123 if (status < 0)
124 goto bail;
125
126 /* We don't want to honor O_APPEND at read/write time as it
127 * doesn't make sense for LVB writes. */
128 file->f_flags &= ~O_APPEND;
129
130 fp = kmalloc(sizeof(*fp), GFP_NOFS);
131 if (!fp) {
132 status = -ENOMEM;
133 goto bail;
134 }
135 fp->fp_lock_level = level;
136
137 ip = DLMFS_I(inode);
138
139 status = user_dlm_cluster_lock(&ip->ip_lockres, level, flags);
140 if (status < 0) {
141 /* this is a strange error to return here but I want
142 * to be able userspace to be able to distinguish a
143 * valid lock request from one that simply couldn't be
144 * granted. */
145 if (flags & LKM_NOQUEUE && status == -EAGAIN)
146 status = -ETXTBSY;
147 kfree(fp);
148 goto bail;
149 }
150
151 file->private_data = fp;
152 bail:
153 return status;
154 }
155
156 static int dlmfs_file_release(struct inode *inode,
157 struct file *file)
158 {
159 int level, status;
160 struct dlmfs_inode_private *ip = DLMFS_I(inode);
161 struct dlmfs_filp_private *fp =
162 (struct dlmfs_filp_private *) file->private_data;
163
164 if (S_ISDIR(inode->i_mode))
165 BUG();
166
167 mlog(0, "close called on inode %lu\n", inode->i_ino);
168
169 status = 0;
170 if (fp) {
171 level = fp->fp_lock_level;
172 if (level != LKM_IVMODE)
173 user_dlm_cluster_unlock(&ip->ip_lockres, level);
174
175 kfree(fp);
176 file->private_data = NULL;
177 }
178
179 return 0;
180 }
181
182 static ssize_t dlmfs_file_read(struct file *filp,
183 char __user *buf,
184 size_t count,
185 loff_t *ppos)
186 {
187 int bytes_left;
188 ssize_t readlen;
189 char *lvb_buf;
190 struct inode *inode = filp->f_path.dentry->d_inode;
191
192 mlog(0, "inode %lu, count = %zu, *ppos = %llu\n",
193 inode->i_ino, count, *ppos);
194
195 if (*ppos >= i_size_read(inode))
196 return 0;
197
198 if (!count)
199 return 0;
200
201 if (!access_ok(VERIFY_WRITE, buf, count))
202 return -EFAULT;
203
204 /* don't read past the lvb */
205 if ((count + *ppos) > i_size_read(inode))
206 readlen = i_size_read(inode) - *ppos;
207 else
208 readlen = count - *ppos;
209
210 lvb_buf = kmalloc(readlen, GFP_NOFS);
211 if (!lvb_buf)
212 return -ENOMEM;
213
214 user_dlm_read_lvb(inode, lvb_buf, readlen);
215 bytes_left = __copy_to_user(buf, lvb_buf, readlen);
216 readlen -= bytes_left;
217
218 kfree(lvb_buf);
219
220 *ppos = *ppos + readlen;
221
222 mlog(0, "read %zd bytes\n", readlen);
223 return readlen;
224 }
225
226 static ssize_t dlmfs_file_write(struct file *filp,
227 const char __user *buf,
228 size_t count,
229 loff_t *ppos)
230 {
231 int bytes_left;
232 ssize_t writelen;
233 char *lvb_buf;
234 struct inode *inode = filp->f_path.dentry->d_inode;
235
236 mlog(0, "inode %lu, count = %zu, *ppos = %llu\n",
237 inode->i_ino, count, *ppos);
238
239 if (*ppos >= i_size_read(inode))
240 return -ENOSPC;
241
242 if (!count)
243 return 0;
244
245 if (!access_ok(VERIFY_READ, buf, count))
246 return -EFAULT;
247
248 /* don't write past the lvb */
249 if ((count + *ppos) > i_size_read(inode))
250 writelen = i_size_read(inode) - *ppos;
251 else
252 writelen = count - *ppos;
253
254 lvb_buf = kmalloc(writelen, GFP_NOFS);
255 if (!lvb_buf)
256 return -ENOMEM;
257
258 bytes_left = copy_from_user(lvb_buf, buf, writelen);
259 writelen -= bytes_left;
260 if (writelen)
261 user_dlm_write_lvb(inode, lvb_buf, writelen);
262
263 kfree(lvb_buf);
264
265 *ppos = *ppos + writelen;
266 mlog(0, "wrote %zd bytes\n", writelen);
267 return writelen;
268 }
269
270 static void dlmfs_init_once(struct kmem_cache *cachep,
271 void *foo)
272 {
273 struct dlmfs_inode_private *ip =
274 (struct dlmfs_inode_private *) foo;
275
276 ip->ip_dlm = NULL;
277 ip->ip_parent = NULL;
278
279 inode_init_once(&ip->ip_vfs_inode);
280 }
281
282 static struct inode *dlmfs_alloc_inode(struct super_block *sb)
283 {
284 struct dlmfs_inode_private *ip;
285
286 ip = kmem_cache_alloc(dlmfs_inode_cache, GFP_NOFS);
287 if (!ip)
288 return NULL;
289
290 return &ip->ip_vfs_inode;
291 }
292
293 static void dlmfs_destroy_inode(struct inode *inode)
294 {
295 kmem_cache_free(dlmfs_inode_cache, DLMFS_I(inode));
296 }
297
298 static void dlmfs_clear_inode(struct inode *inode)
299 {
300 int status;
301 struct dlmfs_inode_private *ip;
302
303 if (!inode)
304 return;
305
306 mlog(0, "inode %lu\n", inode->i_ino);
307
308 ip = DLMFS_I(inode);
309
310 if (S_ISREG(inode->i_mode)) {
311 status = user_dlm_destroy_lock(&ip->ip_lockres);
312 if (status < 0)
313 mlog_errno(status);
314 iput(ip->ip_parent);
315 goto clear_fields;
316 }
317
318 mlog(0, "we're a directory, ip->ip_dlm = 0x%p\n", ip->ip_dlm);
319 /* we must be a directory. If required, lets unregister the
320 * dlm context now. */
321 if (ip->ip_dlm)
322 user_dlm_unregister_context(ip->ip_dlm);
323 clear_fields:
324 ip->ip_parent = NULL;
325 ip->ip_dlm = NULL;
326 }
327
328 static struct backing_dev_info dlmfs_backing_dev_info = {
329 .ra_pages = 0, /* No readahead */
330 .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
331 };
332
333 static struct inode *dlmfs_get_root_inode(struct super_block *sb)
334 {
335 struct inode *inode = new_inode(sb);
336 int mode = S_IFDIR | 0755;
337 struct dlmfs_inode_private *ip;
338
339 if (inode) {
340 ip = DLMFS_I(inode);
341
342 inode->i_mode = mode;
343 inode->i_uid = current->fsuid;
344 inode->i_gid = current->fsgid;
345 inode->i_blocks = 0;
346 inode->i_mapping->backing_dev_info = &dlmfs_backing_dev_info;
347 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
348 inc_nlink(inode);
349
350 inode->i_fop = &simple_dir_operations;
351 inode->i_op = &dlmfs_root_inode_operations;
352 }
353
354 return inode;
355 }
356
357 static struct inode *dlmfs_get_inode(struct inode *parent,
358 struct dentry *dentry,
359 int mode)
360 {
361 struct super_block *sb = parent->i_sb;
362 struct inode * inode = new_inode(sb);
363 struct dlmfs_inode_private *ip;
364
365 if (!inode)
366 return NULL;
367
368 inode->i_mode = mode;
369 inode->i_uid = current->fsuid;
370 inode->i_gid = current->fsgid;
371 inode->i_blocks = 0;
372 inode->i_mapping->backing_dev_info = &dlmfs_backing_dev_info;
373 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
374
375 ip = DLMFS_I(inode);
376 ip->ip_dlm = DLMFS_I(parent)->ip_dlm;
377
378 switch (mode & S_IFMT) {
379 default:
380 /* for now we don't support anything other than
381 * directories and regular files. */
382 BUG();
383 break;
384 case S_IFREG:
385 inode->i_op = &dlmfs_file_inode_operations;
386 inode->i_fop = &dlmfs_file_operations;
387
388 i_size_write(inode, DLM_LVB_LEN);
389
390 user_dlm_lock_res_init(&ip->ip_lockres, dentry);
391
392 /* released at clear_inode time, this insures that we
393 * get to drop the dlm reference on each lock *before*
394 * we call the unregister code for releasing parent
395 * directories. */
396 ip->ip_parent = igrab(parent);
397 BUG_ON(!ip->ip_parent);
398 break;
399 case S_IFDIR:
400 inode->i_op = &dlmfs_dir_inode_operations;
401 inode->i_fop = &simple_dir_operations;
402
403 /* directory inodes start off with i_nlink ==
404 * 2 (for "." entry) */
405 inc_nlink(inode);
406 break;
407 }
408
409 if (parent->i_mode & S_ISGID) {
410 inode->i_gid = parent->i_gid;
411 if (S_ISDIR(mode))
412 inode->i_mode |= S_ISGID;
413 }
414
415 return inode;
416 }
417
418 /*
419 * File creation. Allocate an inode, and we're done..
420 */
421 /* SMP-safe */
422 static int dlmfs_mkdir(struct inode * dir,
423 struct dentry * dentry,
424 int mode)
425 {
426 int status;
427 struct inode *inode = NULL;
428 struct qstr *domain = &dentry->d_name;
429 struct dlmfs_inode_private *ip;
430 struct dlm_ctxt *dlm;
431 struct dlm_protocol_version proto = user_locking_protocol;
432
433 mlog(0, "mkdir %.*s\n", domain->len, domain->name);
434
435 /* verify that we have a proper domain */
436 if (domain->len >= O2NM_MAX_NAME_LEN) {
437 status = -EINVAL;
438 mlog(ML_ERROR, "invalid domain name for directory.\n");
439 goto bail;
440 }
441
442 inode = dlmfs_get_inode(dir, dentry, mode | S_IFDIR);
443 if (!inode) {
444 status = -ENOMEM;
445 mlog_errno(status);
446 goto bail;
447 }
448
449 ip = DLMFS_I(inode);
450
451 dlm = user_dlm_register_context(domain, &proto);
452 if (IS_ERR(dlm)) {
453 status = PTR_ERR(dlm);
454 mlog(ML_ERROR, "Error %d could not register domain \"%.*s\"\n",
455 status, domain->len, domain->name);
456 goto bail;
457 }
458 ip->ip_dlm = dlm;
459
460 inc_nlink(dir);
461 d_instantiate(dentry, inode);
462 dget(dentry); /* Extra count - pin the dentry in core */
463
464 status = 0;
465 bail:
466 if (status < 0)
467 iput(inode);
468 return status;
469 }
470
471 static int dlmfs_create(struct inode *dir,
472 struct dentry *dentry,
473 int mode,
474 struct nameidata *nd)
475 {
476 int status = 0;
477 struct inode *inode;
478 struct qstr *name = &dentry->d_name;
479
480 mlog(0, "create %.*s\n", name->len, name->name);
481
482 /* verify name is valid and doesn't contain any dlm reserved
483 * characters */
484 if (name->len >= USER_DLM_LOCK_ID_MAX_LEN ||
485 name->name[0] == '$') {
486 status = -EINVAL;
487 mlog(ML_ERROR, "invalid lock name, %.*s\n", name->len,
488 name->name);
489 goto bail;
490 }
491
492 inode = dlmfs_get_inode(dir, dentry, mode | S_IFREG);
493 if (!inode) {
494 status = -ENOMEM;
495 mlog_errno(status);
496 goto bail;
497 }
498
499 d_instantiate(dentry, inode);
500 dget(dentry); /* Extra count - pin the dentry in core */
501 bail:
502 return status;
503 }
504
505 static int dlmfs_unlink(struct inode *dir,
506 struct dentry *dentry)
507 {
508 int status;
509 struct inode *inode = dentry->d_inode;
510
511 mlog(0, "unlink inode %lu\n", inode->i_ino);
512
513 /* if there are no current holders, or none that are waiting
514 * to acquire a lock, this basically destroys our lockres. */
515 status = user_dlm_destroy_lock(&DLMFS_I(inode)->ip_lockres);
516 if (status < 0) {
517 mlog(ML_ERROR, "unlink %.*s, error %d from destroy\n",
518 dentry->d_name.len, dentry->d_name.name, status);
519 goto bail;
520 }
521 status = simple_unlink(dir, dentry);
522 bail:
523 return status;
524 }
525
526 static int dlmfs_fill_super(struct super_block * sb,
527 void * data,
528 int silent)
529 {
530 struct inode * inode;
531 struct dentry * root;
532
533 sb->s_maxbytes = MAX_LFS_FILESIZE;
534 sb->s_blocksize = PAGE_CACHE_SIZE;
535 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
536 sb->s_magic = DLMFS_MAGIC;
537 sb->s_op = &dlmfs_ops;
538 inode = dlmfs_get_root_inode(sb);
539 if (!inode)
540 return -ENOMEM;
541
542 root = d_alloc_root(inode);
543 if (!root) {
544 iput(inode);
545 return -ENOMEM;
546 }
547 sb->s_root = root;
548 return 0;
549 }
550
551 static const struct file_operations dlmfs_file_operations = {
552 .open = dlmfs_file_open,
553 .release = dlmfs_file_release,
554 .read = dlmfs_file_read,
555 .write = dlmfs_file_write,
556 };
557
558 static const struct inode_operations dlmfs_dir_inode_operations = {
559 .create = dlmfs_create,
560 .lookup = simple_lookup,
561 .unlink = dlmfs_unlink,
562 };
563
564 /* this way we can restrict mkdir to only the toplevel of the fs. */
565 static const struct inode_operations dlmfs_root_inode_operations = {
566 .lookup = simple_lookup,
567 .mkdir = dlmfs_mkdir,
568 .rmdir = simple_rmdir,
569 };
570
571 static const struct super_operations dlmfs_ops = {
572 .statfs = simple_statfs,
573 .alloc_inode = dlmfs_alloc_inode,
574 .destroy_inode = dlmfs_destroy_inode,
575 .clear_inode = dlmfs_clear_inode,
576 .drop_inode = generic_delete_inode,
577 };
578
579 static const struct inode_operations dlmfs_file_inode_operations = {
580 .getattr = simple_getattr,
581 };
582
583 static int dlmfs_get_sb(struct file_system_type *fs_type,
584 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
585 {
586 return get_sb_nodev(fs_type, flags, data, dlmfs_fill_super, mnt);
587 }
588
589 static struct file_system_type dlmfs_fs_type = {
590 .owner = THIS_MODULE,
591 .name = "ocfs2_dlmfs",
592 .get_sb = dlmfs_get_sb,
593 .kill_sb = kill_litter_super,
594 };
595
596 static int __init init_dlmfs_fs(void)
597 {
598 int status;
599 int cleanup_inode = 0, cleanup_worker = 0;
600
601 dlmfs_print_version();
602
603 status = bdi_init(&dlmfs_backing_dev_info);
604 if (status)
605 return status;
606
607 dlmfs_inode_cache = kmem_cache_create("dlmfs_inode_cache",
608 sizeof(struct dlmfs_inode_private),
609 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
610 SLAB_MEM_SPREAD),
611 dlmfs_init_once);
612 if (!dlmfs_inode_cache)
613 goto bail;
614 cleanup_inode = 1;
615
616 user_dlm_worker = create_singlethread_workqueue("user_dlm");
617 if (!user_dlm_worker) {
618 status = -ENOMEM;
619 goto bail;
620 }
621 cleanup_worker = 1;
622
623 status = register_filesystem(&dlmfs_fs_type);
624 bail:
625 if (status) {
626 if (cleanup_inode)
627 kmem_cache_destroy(dlmfs_inode_cache);
628 if (cleanup_worker)
629 destroy_workqueue(user_dlm_worker);
630 bdi_destroy(&dlmfs_backing_dev_info);
631 } else
632 printk("OCFS2 User DLM kernel interface loaded\n");
633 return status;
634 }
635
636 static void __exit exit_dlmfs_fs(void)
637 {
638 unregister_filesystem(&dlmfs_fs_type);
639
640 flush_workqueue(user_dlm_worker);
641 destroy_workqueue(user_dlm_worker);
642
643 kmem_cache_destroy(dlmfs_inode_cache);
644
645 bdi_destroy(&dlmfs_backing_dev_info);
646 }
647
648 MODULE_AUTHOR("Oracle");
649 MODULE_LICENSE("GPL");
650
651 module_init(init_dlmfs_fs)
652 module_exit(exit_dlmfs_fs)
653
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