Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
[linux-2.6/libata-dev.git] / fs / ocfs2 / dlmfs / dlmfs.c
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1 /* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
4 * dlmfs.c
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.
11 * Copyright (C) 2003, 2004 Oracle. All rights reserved.
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.
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.
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.
29 /* Simple VFS hooks based on: */
31 * Resizable simple ram filesystem for Linux.
33 * Copyright (C) 2000 Linus Torvalds.
34 * 2000 Transmeta Corp.
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>
48 #include <asm/uaccess.h>
50 #include "stackglue.h"
51 #include "userdlm.h"
52 #include "dlmfsver.h"
54 #define MLOG_MASK_PREFIX ML_DLMFS
55 #include "cluster/masklog.h"
58 static const struct super_operations dlmfs_ops;
59 static const struct file_operations dlmfs_file_operations;
60 static const struct inode_operations dlmfs_dir_inode_operations;
61 static const struct inode_operations dlmfs_root_inode_operations;
62 static const struct inode_operations dlmfs_file_inode_operations;
63 static struct kmem_cache *dlmfs_inode_cache;
65 struct workqueue_struct *user_dlm_worker;
70 * These are the ABI capabilities of dlmfs.
72 * Over time, dlmfs has added some features that were not part of the
73 * initial ABI. Unfortunately, some of these features are not detectable
74 * via standard usage. For example, Linux's default poll always returns
75 * POLLIN, so there is no way for a caller of poll(2) to know when dlmfs
76 * added poll support. Instead, we provide this list of new capabilities.
78 * Capabilities is a read-only attribute. We do it as a module parameter
79 * so we can discover it whether dlmfs is built in, loaded, or even not
80 * loaded.
82 * The ABI features are local to this machine's dlmfs mount. This is
83 * distinct from the locking protocol, which is concerned with inter-node
84 * interaction.
86 * Capabilities:
87 * - bast : POLLIN against the file descriptor of a held lock
88 * signifies a bast fired on the lock.
90 #define DLMFS_CAPABILITIES "bast stackglue"
91 static int param_set_dlmfs_capabilities(const char *val,
92 struct kernel_param *kp)
94 printk(KERN_ERR "%s: readonly parameter\n", kp->name);
95 return -EINVAL;
97 static int param_get_dlmfs_capabilities(char *buffer,
98 struct kernel_param *kp)
100 return strlcpy(buffer, DLMFS_CAPABILITIES,
101 strlen(DLMFS_CAPABILITIES) + 1);
103 module_param_call(capabilities, param_set_dlmfs_capabilities,
104 param_get_dlmfs_capabilities, NULL, 0444);
105 MODULE_PARM_DESC(capabilities, DLMFS_CAPABILITIES);
109 * decodes a set of open flags into a valid lock level and a set of flags.
110 * returns < 0 if we have invalid flags
111 * flags which mean something to us:
112 * O_RDONLY -> PRMODE level
113 * O_WRONLY -> EXMODE level
115 * O_NONBLOCK -> NOQUEUE
117 static int dlmfs_decode_open_flags(int open_flags,
118 int *level,
119 int *flags)
121 if (open_flags & (O_WRONLY|O_RDWR))
122 *level = DLM_LOCK_EX;
123 else
124 *level = DLM_LOCK_PR;
126 *flags = 0;
127 if (open_flags & O_NONBLOCK)
128 *flags |= DLM_LKF_NOQUEUE;
130 return 0;
133 static int dlmfs_file_open(struct inode *inode,
134 struct file *file)
136 int status, level, flags;
137 struct dlmfs_filp_private *fp = NULL;
138 struct dlmfs_inode_private *ip;
140 if (S_ISDIR(inode->i_mode))
141 BUG();
143 mlog(0, "open called on inode %lu, flags 0x%x\n", inode->i_ino,
144 file->f_flags);
146 status = dlmfs_decode_open_flags(file->f_flags, &level, &flags);
147 if (status < 0)
148 goto bail;
150 /* We don't want to honor O_APPEND at read/write time as it
151 * doesn't make sense for LVB writes. */
152 file->f_flags &= ~O_APPEND;
154 fp = kmalloc(sizeof(*fp), GFP_NOFS);
155 if (!fp) {
156 status = -ENOMEM;
157 goto bail;
159 fp->fp_lock_level = level;
161 ip = DLMFS_I(inode);
163 status = user_dlm_cluster_lock(&ip->ip_lockres, level, flags);
164 if (status < 0) {
165 /* this is a strange error to return here but I want
166 * to be able userspace to be able to distinguish a
167 * valid lock request from one that simply couldn't be
168 * granted. */
169 if (flags & DLM_LKF_NOQUEUE && status == -EAGAIN)
170 status = -ETXTBSY;
171 kfree(fp);
172 goto bail;
175 file->private_data = fp;
176 bail:
177 return status;
180 static int dlmfs_file_release(struct inode *inode,
181 struct file *file)
183 int level, status;
184 struct dlmfs_inode_private *ip = DLMFS_I(inode);
185 struct dlmfs_filp_private *fp = file->private_data;
187 if (S_ISDIR(inode->i_mode))
188 BUG();
190 mlog(0, "close called on inode %lu\n", inode->i_ino);
192 status = 0;
193 if (fp) {
194 level = fp->fp_lock_level;
195 if (level != DLM_LOCK_IV)
196 user_dlm_cluster_unlock(&ip->ip_lockres, level);
198 kfree(fp);
199 file->private_data = NULL;
202 return 0;
206 * We do ->setattr() just to override size changes. Our size is the size
207 * of the LVB and nothing else.
209 static int dlmfs_file_setattr(struct dentry *dentry, struct iattr *attr)
211 int error;
212 struct inode *inode = dentry->d_inode;
214 attr->ia_valid &= ~ATTR_SIZE;
215 error = inode_change_ok(inode, attr);
216 if (error)
217 return error;
219 setattr_copy(inode, attr);
220 mark_inode_dirty(inode);
221 return 0;
224 static unsigned int dlmfs_file_poll(struct file *file, poll_table *wait)
226 int event = 0;
227 struct inode *inode = file_inode(file);
228 struct dlmfs_inode_private *ip = DLMFS_I(inode);
230 poll_wait(file, &ip->ip_lockres.l_event, wait);
232 spin_lock(&ip->ip_lockres.l_lock);
233 if (ip->ip_lockres.l_flags & USER_LOCK_BLOCKED)
234 event = POLLIN | POLLRDNORM;
235 spin_unlock(&ip->ip_lockres.l_lock);
237 return event;
240 static ssize_t dlmfs_file_read(struct file *filp,
241 char __user *buf,
242 size_t count,
243 loff_t *ppos)
245 int bytes_left;
246 ssize_t readlen, got;
247 char *lvb_buf;
248 struct inode *inode = file_inode(filp);
250 mlog(0, "inode %lu, count = %zu, *ppos = %llu\n",
251 inode->i_ino, count, *ppos);
253 if (*ppos >= i_size_read(inode))
254 return 0;
256 if (!count)
257 return 0;
259 if (!access_ok(VERIFY_WRITE, buf, count))
260 return -EFAULT;
262 /* don't read past the lvb */
263 if ((count + *ppos) > i_size_read(inode))
264 readlen = i_size_read(inode) - *ppos;
265 else
266 readlen = count;
268 lvb_buf = kmalloc(readlen, GFP_NOFS);
269 if (!lvb_buf)
270 return -ENOMEM;
272 got = user_dlm_read_lvb(inode, lvb_buf, readlen);
273 if (got) {
274 BUG_ON(got != readlen);
275 bytes_left = __copy_to_user(buf, lvb_buf, readlen);
276 readlen -= bytes_left;
277 } else
278 readlen = 0;
280 kfree(lvb_buf);
282 *ppos = *ppos + readlen;
284 mlog(0, "read %zd bytes\n", readlen);
285 return readlen;
288 static ssize_t dlmfs_file_write(struct file *filp,
289 const char __user *buf,
290 size_t count,
291 loff_t *ppos)
293 int bytes_left;
294 ssize_t writelen;
295 char *lvb_buf;
296 struct inode *inode = file_inode(filp);
298 mlog(0, "inode %lu, count = %zu, *ppos = %llu\n",
299 inode->i_ino, count, *ppos);
301 if (*ppos >= i_size_read(inode))
302 return -ENOSPC;
304 if (!count)
305 return 0;
307 if (!access_ok(VERIFY_READ, buf, count))
308 return -EFAULT;
310 /* don't write past the lvb */
311 if ((count + *ppos) > i_size_read(inode))
312 writelen = i_size_read(inode) - *ppos;
313 else
314 writelen = count - *ppos;
316 lvb_buf = kmalloc(writelen, GFP_NOFS);
317 if (!lvb_buf)
318 return -ENOMEM;
320 bytes_left = copy_from_user(lvb_buf, buf, writelen);
321 writelen -= bytes_left;
322 if (writelen)
323 user_dlm_write_lvb(inode, lvb_buf, writelen);
325 kfree(lvb_buf);
327 *ppos = *ppos + writelen;
328 mlog(0, "wrote %zd bytes\n", writelen);
329 return writelen;
332 static void dlmfs_init_once(void *foo)
334 struct dlmfs_inode_private *ip =
335 (struct dlmfs_inode_private *) foo;
337 ip->ip_conn = NULL;
338 ip->ip_parent = NULL;
340 inode_init_once(&ip->ip_vfs_inode);
343 static struct inode *dlmfs_alloc_inode(struct super_block *sb)
345 struct dlmfs_inode_private *ip;
347 ip = kmem_cache_alloc(dlmfs_inode_cache, GFP_NOFS);
348 if (!ip)
349 return NULL;
351 return &ip->ip_vfs_inode;
354 static void dlmfs_i_callback(struct rcu_head *head)
356 struct inode *inode = container_of(head, struct inode, i_rcu);
357 kmem_cache_free(dlmfs_inode_cache, DLMFS_I(inode));
360 static void dlmfs_destroy_inode(struct inode *inode)
362 call_rcu(&inode->i_rcu, dlmfs_i_callback);
365 static void dlmfs_evict_inode(struct inode *inode)
367 int status;
368 struct dlmfs_inode_private *ip;
370 clear_inode(inode);
372 mlog(0, "inode %lu\n", inode->i_ino);
374 ip = DLMFS_I(inode);
376 if (S_ISREG(inode->i_mode)) {
377 status = user_dlm_destroy_lock(&ip->ip_lockres);
378 if (status < 0)
379 mlog_errno(status);
380 iput(ip->ip_parent);
381 goto clear_fields;
384 mlog(0, "we're a directory, ip->ip_conn = 0x%p\n", ip->ip_conn);
385 /* we must be a directory. If required, lets unregister the
386 * dlm context now. */
387 if (ip->ip_conn)
388 user_dlm_unregister(ip->ip_conn);
389 clear_fields:
390 ip->ip_parent = NULL;
391 ip->ip_conn = NULL;
394 static struct backing_dev_info dlmfs_backing_dev_info = {
395 .name = "ocfs2-dlmfs",
396 .ra_pages = 0, /* No readahead */
397 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
400 static struct inode *dlmfs_get_root_inode(struct super_block *sb)
402 struct inode *inode = new_inode(sb);
403 umode_t mode = S_IFDIR | 0755;
404 struct dlmfs_inode_private *ip;
406 if (inode) {
407 ip = DLMFS_I(inode);
409 inode->i_ino = get_next_ino();
410 inode_init_owner(inode, NULL, mode);
411 inode->i_mapping->backing_dev_info = &dlmfs_backing_dev_info;
412 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
413 inc_nlink(inode);
415 inode->i_fop = &simple_dir_operations;
416 inode->i_op = &dlmfs_root_inode_operations;
419 return inode;
422 static struct inode *dlmfs_get_inode(struct inode *parent,
423 struct dentry *dentry,
424 umode_t mode)
426 struct super_block *sb = parent->i_sb;
427 struct inode * inode = new_inode(sb);
428 struct dlmfs_inode_private *ip;
430 if (!inode)
431 return NULL;
433 inode->i_ino = get_next_ino();
434 inode_init_owner(inode, parent, mode);
435 inode->i_mapping->backing_dev_info = &dlmfs_backing_dev_info;
436 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
438 ip = DLMFS_I(inode);
439 ip->ip_conn = DLMFS_I(parent)->ip_conn;
441 switch (mode & S_IFMT) {
442 default:
443 /* for now we don't support anything other than
444 * directories and regular files. */
445 BUG();
446 break;
447 case S_IFREG:
448 inode->i_op = &dlmfs_file_inode_operations;
449 inode->i_fop = &dlmfs_file_operations;
451 i_size_write(inode, DLM_LVB_LEN);
453 user_dlm_lock_res_init(&ip->ip_lockres, dentry);
455 /* released at clear_inode time, this insures that we
456 * get to drop the dlm reference on each lock *before*
457 * we call the unregister code for releasing parent
458 * directories. */
459 ip->ip_parent = igrab(parent);
460 BUG_ON(!ip->ip_parent);
461 break;
462 case S_IFDIR:
463 inode->i_op = &dlmfs_dir_inode_operations;
464 inode->i_fop = &simple_dir_operations;
466 /* directory inodes start off with i_nlink ==
467 * 2 (for "." entry) */
468 inc_nlink(inode);
469 break;
471 return inode;
475 * File creation. Allocate an inode, and we're done..
477 /* SMP-safe */
478 static int dlmfs_mkdir(struct inode * dir,
479 struct dentry * dentry,
480 umode_t mode)
482 int status;
483 struct inode *inode = NULL;
484 struct qstr *domain = &dentry->d_name;
485 struct dlmfs_inode_private *ip;
486 struct ocfs2_cluster_connection *conn;
488 mlog(0, "mkdir %.*s\n", domain->len, domain->name);
490 /* verify that we have a proper domain */
491 if (domain->len >= GROUP_NAME_MAX) {
492 status = -EINVAL;
493 mlog(ML_ERROR, "invalid domain name for directory.\n");
494 goto bail;
497 inode = dlmfs_get_inode(dir, dentry, mode | S_IFDIR);
498 if (!inode) {
499 status = -ENOMEM;
500 mlog_errno(status);
501 goto bail;
504 ip = DLMFS_I(inode);
506 conn = user_dlm_register(domain);
507 if (IS_ERR(conn)) {
508 status = PTR_ERR(conn);
509 mlog(ML_ERROR, "Error %d could not register domain \"%.*s\"\n",
510 status, domain->len, domain->name);
511 goto bail;
513 ip->ip_conn = conn;
515 inc_nlink(dir);
516 d_instantiate(dentry, inode);
517 dget(dentry); /* Extra count - pin the dentry in core */
519 status = 0;
520 bail:
521 if (status < 0)
522 iput(inode);
523 return status;
526 static int dlmfs_create(struct inode *dir,
527 struct dentry *dentry,
528 umode_t mode,
529 bool excl)
531 int status = 0;
532 struct inode *inode;
533 struct qstr *name = &dentry->d_name;
535 mlog(0, "create %.*s\n", name->len, name->name);
537 /* verify name is valid and doesn't contain any dlm reserved
538 * characters */
539 if (name->len >= USER_DLM_LOCK_ID_MAX_LEN ||
540 name->name[0] == '$') {
541 status = -EINVAL;
542 mlog(ML_ERROR, "invalid lock name, %.*s\n", name->len,
543 name->name);
544 goto bail;
547 inode = dlmfs_get_inode(dir, dentry, mode | S_IFREG);
548 if (!inode) {
549 status = -ENOMEM;
550 mlog_errno(status);
551 goto bail;
554 d_instantiate(dentry, inode);
555 dget(dentry); /* Extra count - pin the dentry in core */
556 bail:
557 return status;
560 static int dlmfs_unlink(struct inode *dir,
561 struct dentry *dentry)
563 int status;
564 struct inode *inode = dentry->d_inode;
566 mlog(0, "unlink inode %lu\n", inode->i_ino);
568 /* if there are no current holders, or none that are waiting
569 * to acquire a lock, this basically destroys our lockres. */
570 status = user_dlm_destroy_lock(&DLMFS_I(inode)->ip_lockres);
571 if (status < 0) {
572 mlog(ML_ERROR, "unlink %.*s, error %d from destroy\n",
573 dentry->d_name.len, dentry->d_name.name, status);
574 goto bail;
576 status = simple_unlink(dir, dentry);
577 bail:
578 return status;
581 static int dlmfs_fill_super(struct super_block * sb,
582 void * data,
583 int silent)
585 sb->s_maxbytes = MAX_LFS_FILESIZE;
586 sb->s_blocksize = PAGE_CACHE_SIZE;
587 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
588 sb->s_magic = DLMFS_MAGIC;
589 sb->s_op = &dlmfs_ops;
590 sb->s_root = d_make_root(dlmfs_get_root_inode(sb));
591 if (!sb->s_root)
592 return -ENOMEM;
593 return 0;
596 static const struct file_operations dlmfs_file_operations = {
597 .open = dlmfs_file_open,
598 .release = dlmfs_file_release,
599 .poll = dlmfs_file_poll,
600 .read = dlmfs_file_read,
601 .write = dlmfs_file_write,
602 .llseek = default_llseek,
605 static const struct inode_operations dlmfs_dir_inode_operations = {
606 .create = dlmfs_create,
607 .lookup = simple_lookup,
608 .unlink = dlmfs_unlink,
611 /* this way we can restrict mkdir to only the toplevel of the fs. */
612 static const struct inode_operations dlmfs_root_inode_operations = {
613 .lookup = simple_lookup,
614 .mkdir = dlmfs_mkdir,
615 .rmdir = simple_rmdir,
618 static const struct super_operations dlmfs_ops = {
619 .statfs = simple_statfs,
620 .alloc_inode = dlmfs_alloc_inode,
621 .destroy_inode = dlmfs_destroy_inode,
622 .evict_inode = dlmfs_evict_inode,
623 .drop_inode = generic_delete_inode,
626 static const struct inode_operations dlmfs_file_inode_operations = {
627 .getattr = simple_getattr,
628 .setattr = dlmfs_file_setattr,
631 static struct dentry *dlmfs_mount(struct file_system_type *fs_type,
632 int flags, const char *dev_name, void *data)
634 return mount_nodev(fs_type, flags, data, dlmfs_fill_super);
637 static struct file_system_type dlmfs_fs_type = {
638 .owner = THIS_MODULE,
639 .name = "ocfs2_dlmfs",
640 .mount = dlmfs_mount,
641 .kill_sb = kill_litter_super,
643 MODULE_ALIAS_FS("ocfs2_dlmfs");
645 static int __init init_dlmfs_fs(void)
647 int status;
648 int cleanup_inode = 0, cleanup_worker = 0;
650 dlmfs_print_version();
652 status = bdi_init(&dlmfs_backing_dev_info);
653 if (status)
654 return status;
656 dlmfs_inode_cache = kmem_cache_create("dlmfs_inode_cache",
657 sizeof(struct dlmfs_inode_private),
658 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
659 SLAB_MEM_SPREAD),
660 dlmfs_init_once);
661 if (!dlmfs_inode_cache) {
662 status = -ENOMEM;
663 goto bail;
665 cleanup_inode = 1;
667 user_dlm_worker = create_singlethread_workqueue("user_dlm");
668 if (!user_dlm_worker) {
669 status = -ENOMEM;
670 goto bail;
672 cleanup_worker = 1;
674 user_dlm_set_locking_protocol();
675 status = register_filesystem(&dlmfs_fs_type);
676 bail:
677 if (status) {
678 if (cleanup_inode)
679 kmem_cache_destroy(dlmfs_inode_cache);
680 if (cleanup_worker)
681 destroy_workqueue(user_dlm_worker);
682 bdi_destroy(&dlmfs_backing_dev_info);
683 } else
684 printk("OCFS2 User DLM kernel interface loaded\n");
685 return status;
688 static void __exit exit_dlmfs_fs(void)
690 unregister_filesystem(&dlmfs_fs_type);
692 flush_workqueue(user_dlm_worker);
693 destroy_workqueue(user_dlm_worker);
696 * Make sure all delayed rcu free inodes are flushed before we
697 * destroy cache.
699 rcu_barrier();
700 kmem_cache_destroy(dlmfs_inode_cache);
702 bdi_destroy(&dlmfs_backing_dev_info);
705 MODULE_AUTHOR("Oracle");
706 MODULE_LICENSE("GPL");
708 module_init(init_dlmfs_fs)
709 module_exit(exit_dlmfs_fs)