xref: /linux/fs/gfs2/super.c (revision b454cc6636d254fbf6049b73e9560aee76fb04a3)
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
4  *
5  * This copyrighted material is made available to anyone wishing to use,
6  * modify, copy, or redistribute it subject to the terms and conditions
7  * of the GNU General Public License version 2.
8  */
9 
10 #include <linux/sched.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 #include <linux/completion.h>
14 #include <linux/buffer_head.h>
15 #include <linux/crc32.h>
16 #include <linux/gfs2_ondisk.h>
17 #include <linux/bio.h>
18 #include <linux/lm_interface.h>
19 
20 #include "gfs2.h"
21 #include "incore.h"
22 #include "bmap.h"
23 #include "dir.h"
24 #include "glock.h"
25 #include "glops.h"
26 #include "inode.h"
27 #include "log.h"
28 #include "meta_io.h"
29 #include "quota.h"
30 #include "recovery.h"
31 #include "rgrp.h"
32 #include "super.h"
33 #include "trans.h"
34 #include "util.h"
35 
36 static const u32 gfs2_old_fs_formats[] = {
37         0
38 };
39 
40 static const u32 gfs2_old_multihost_formats[] = {
41         0
42 };
43 
44 /**
45  * gfs2_tune_init - Fill a gfs2_tune structure with default values
46  * @gt: tune
47  *
48  */
49 
50 void gfs2_tune_init(struct gfs2_tune *gt)
51 {
52 	spin_lock_init(&gt->gt_spin);
53 
54 	gt->gt_ilimit = 100;
55 	gt->gt_ilimit_tries = 3;
56 	gt->gt_ilimit_min = 1;
57 	gt->gt_demote_secs = 300;
58 	gt->gt_incore_log_blocks = 1024;
59 	gt->gt_log_flush_secs = 60;
60 	gt->gt_jindex_refresh_secs = 60;
61 	gt->gt_scand_secs = 15;
62 	gt->gt_recoverd_secs = 60;
63 	gt->gt_logd_secs = 1;
64 	gt->gt_quotad_secs = 5;
65 	gt->gt_quota_simul_sync = 64;
66 	gt->gt_quota_warn_period = 10;
67 	gt->gt_quota_scale_num = 1;
68 	gt->gt_quota_scale_den = 1;
69 	gt->gt_quota_cache_secs = 300;
70 	gt->gt_quota_quantum = 60;
71 	gt->gt_atime_quantum = 3600;
72 	gt->gt_new_files_jdata = 0;
73 	gt->gt_new_files_directio = 0;
74 	gt->gt_max_readahead = 1 << 18;
75 	gt->gt_lockdump_size = 131072;
76 	gt->gt_stall_secs = 600;
77 	gt->gt_complain_secs = 10;
78 	gt->gt_reclaim_limit = 5000;
79 	gt->gt_entries_per_readdir = 32;
80 	gt->gt_statfs_quantum = 30;
81 	gt->gt_statfs_slow = 0;
82 }
83 
84 /**
85  * gfs2_check_sb - Check superblock
86  * @sdp: the filesystem
87  * @sb: The superblock
88  * @silent: Don't print a message if the check fails
89  *
90  * Checks the version code of the FS is one that we understand how to
91  * read and that the sizes of the various on-disk structures have not
92  * changed.
93  */
94 
95 int gfs2_check_sb(struct gfs2_sbd *sdp, struct gfs2_sb_host *sb, int silent)
96 {
97 	unsigned int x;
98 
99 	if (sb->sb_header.mh_magic != GFS2_MAGIC ||
100 	    sb->sb_header.mh_type != GFS2_METATYPE_SB) {
101 		if (!silent)
102 			printk(KERN_WARNING "GFS2: not a GFS2 filesystem\n");
103 		return -EINVAL;
104 	}
105 
106 	/*  If format numbers match exactly, we're done.  */
107 
108 	if (sb->sb_fs_format == GFS2_FORMAT_FS &&
109 	    sb->sb_multihost_format == GFS2_FORMAT_MULTI)
110 		return 0;
111 
112 	if (sb->sb_fs_format != GFS2_FORMAT_FS) {
113 		for (x = 0; gfs2_old_fs_formats[x]; x++)
114 			if (gfs2_old_fs_formats[x] == sb->sb_fs_format)
115 				break;
116 
117 		if (!gfs2_old_fs_formats[x]) {
118 			printk(KERN_WARNING
119 			       "GFS2: code version (%u, %u) is incompatible "
120 			       "with ondisk format (%u, %u)\n",
121 			       GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
122 			       sb->sb_fs_format, sb->sb_multihost_format);
123 			printk(KERN_WARNING
124 			       "GFS2: I don't know how to upgrade this FS\n");
125 			return -EINVAL;
126 		}
127 	}
128 
129 	if (sb->sb_multihost_format != GFS2_FORMAT_MULTI) {
130 		for (x = 0; gfs2_old_multihost_formats[x]; x++)
131 			if (gfs2_old_multihost_formats[x] ==
132 			    sb->sb_multihost_format)
133 				break;
134 
135 		if (!gfs2_old_multihost_formats[x]) {
136 			printk(KERN_WARNING
137 			       "GFS2: code version (%u, %u) is incompatible "
138 			       "with ondisk format (%u, %u)\n",
139 			       GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
140 			       sb->sb_fs_format, sb->sb_multihost_format);
141 			printk(KERN_WARNING
142 			       "GFS2: I don't know how to upgrade this FS\n");
143 			return -EINVAL;
144 		}
145 	}
146 
147 	if (!sdp->sd_args.ar_upgrade) {
148 		printk(KERN_WARNING
149 		       "GFS2: code version (%u, %u) is incompatible "
150 		       "with ondisk format (%u, %u)\n",
151 		       GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
152 		       sb->sb_fs_format, sb->sb_multihost_format);
153 		printk(KERN_INFO
154 		       "GFS2: Use the \"upgrade\" mount option to upgrade "
155 		       "the FS\n");
156 		printk(KERN_INFO "GFS2: See the manual for more details\n");
157 		return -EINVAL;
158 	}
159 
160 	return 0;
161 }
162 
163 
164 static int end_bio_io_page(struct bio *bio, unsigned int bytes_done, int error)
165 {
166 	struct page *page = bio->bi_private;
167 	if (bio->bi_size)
168 		return 1;
169 
170 	if (!error)
171 		SetPageUptodate(page);
172 	else
173 		printk(KERN_WARNING "gfs2: error %d reading superblock\n", error);
174 	unlock_page(page);
175 	return 0;
176 }
177 
178 /**
179  * gfs2_read_super - Read the gfs2 super block from disk
180  * @sb: The VFS super block
181  * @sector: The location of the super block
182  *
183  * This uses the bio functions to read the super block from disk
184  * because we want to be 100% sure that we never read cached data.
185  * A super block is read twice only during each GFS2 mount and is
186  * never written to by the filesystem. The first time its read no
187  * locks are held, and the only details which are looked at are those
188  * relating to the locking protocol. Once locking is up and working,
189  * the sb is read again under the lock to establish the location of
190  * the master directory (contains pointers to journals etc) and the
191  * root directory.
192  *
193  * Returns: A page containing the sb or NULL
194  */
195 
196 struct page *gfs2_read_super(struct super_block *sb, sector_t sector)
197 {
198 	struct page *page;
199 	struct bio *bio;
200 
201 	page = alloc_page(GFP_KERNEL);
202 	if (unlikely(!page))
203 		return NULL;
204 
205 	ClearPageUptodate(page);
206 	ClearPageDirty(page);
207 	lock_page(page);
208 
209 	bio = bio_alloc(GFP_KERNEL, 1);
210 	if (unlikely(!bio)) {
211 		__free_page(page);
212 		return NULL;
213 	}
214 
215 	bio->bi_sector = sector * (sb->s_blocksize >> 9);
216 	bio->bi_bdev = sb->s_bdev;
217 	bio_add_page(bio, page, PAGE_SIZE, 0);
218 
219 	bio->bi_end_io = end_bio_io_page;
220 	bio->bi_private = page;
221 	submit_bio(READ_SYNC | (1 << BIO_RW_META), bio);
222 	wait_on_page_locked(page);
223 	bio_put(bio);
224 	if (!PageUptodate(page)) {
225 		__free_page(page);
226 		return NULL;
227 	}
228 	return page;
229 }
230 
231 /**
232  * gfs2_read_sb - Read super block
233  * @sdp: The GFS2 superblock
234  * @gl: the glock for the superblock (assumed to be held)
235  * @silent: Don't print message if mount fails
236  *
237  */
238 
239 int gfs2_read_sb(struct gfs2_sbd *sdp, struct gfs2_glock *gl, int silent)
240 {
241 	u32 hash_blocks, ind_blocks, leaf_blocks;
242 	u32 tmp_blocks;
243 	unsigned int x;
244 	int error;
245 	struct page *page;
246 	char *sb;
247 
248 	page = gfs2_read_super(sdp->sd_vfs, GFS2_SB_ADDR >> sdp->sd_fsb2bb_shift);
249 	if (!page) {
250 		if (!silent)
251 			fs_err(sdp, "can't read superblock\n");
252 		return -EIO;
253 	}
254 	sb = kmap(page);
255 	gfs2_sb_in(&sdp->sd_sb, sb);
256 	kunmap(page);
257 	__free_page(page);
258 
259 	error = gfs2_check_sb(sdp, &sdp->sd_sb, silent);
260 	if (error)
261 		return error;
262 
263 	sdp->sd_fsb2bb_shift = sdp->sd_sb.sb_bsize_shift -
264 			       GFS2_BASIC_BLOCK_SHIFT;
265 	sdp->sd_fsb2bb = 1 << sdp->sd_fsb2bb_shift;
266 	sdp->sd_diptrs = (sdp->sd_sb.sb_bsize -
267 			  sizeof(struct gfs2_dinode)) / sizeof(u64);
268 	sdp->sd_inptrs = (sdp->sd_sb.sb_bsize -
269 			  sizeof(struct gfs2_meta_header)) / sizeof(u64);
270 	sdp->sd_jbsize = sdp->sd_sb.sb_bsize - sizeof(struct gfs2_meta_header);
271 	sdp->sd_hash_bsize = sdp->sd_sb.sb_bsize / 2;
272 	sdp->sd_hash_bsize_shift = sdp->sd_sb.sb_bsize_shift - 1;
273 	sdp->sd_hash_ptrs = sdp->sd_hash_bsize / sizeof(u64);
274 	sdp->sd_qc_per_block = (sdp->sd_sb.sb_bsize -
275 				sizeof(struct gfs2_meta_header)) /
276 			        sizeof(struct gfs2_quota_change);
277 
278 	/* Compute maximum reservation required to add a entry to a directory */
279 
280 	hash_blocks = DIV_ROUND_UP(sizeof(u64) * (1 << GFS2_DIR_MAX_DEPTH),
281 			     sdp->sd_jbsize);
282 
283 	ind_blocks = 0;
284 	for (tmp_blocks = hash_blocks; tmp_blocks > sdp->sd_diptrs;) {
285 		tmp_blocks = DIV_ROUND_UP(tmp_blocks, sdp->sd_inptrs);
286 		ind_blocks += tmp_blocks;
287 	}
288 
289 	leaf_blocks = 2 + GFS2_DIR_MAX_DEPTH;
290 
291 	sdp->sd_max_dirres = hash_blocks + ind_blocks + leaf_blocks;
292 
293 	sdp->sd_heightsize[0] = sdp->sd_sb.sb_bsize -
294 				sizeof(struct gfs2_dinode);
295 	sdp->sd_heightsize[1] = sdp->sd_sb.sb_bsize * sdp->sd_diptrs;
296 	for (x = 2;; x++) {
297 		u64 space, d;
298 		u32 m;
299 
300 		space = sdp->sd_heightsize[x - 1] * sdp->sd_inptrs;
301 		d = space;
302 		m = do_div(d, sdp->sd_inptrs);
303 
304 		if (d != sdp->sd_heightsize[x - 1] || m)
305 			break;
306 		sdp->sd_heightsize[x] = space;
307 	}
308 	sdp->sd_max_height = x;
309 	gfs2_assert(sdp, sdp->sd_max_height <= GFS2_MAX_META_HEIGHT);
310 
311 	sdp->sd_jheightsize[0] = sdp->sd_sb.sb_bsize -
312 				 sizeof(struct gfs2_dinode);
313 	sdp->sd_jheightsize[1] = sdp->sd_jbsize * sdp->sd_diptrs;
314 	for (x = 2;; x++) {
315 		u64 space, d;
316 		u32 m;
317 
318 		space = sdp->sd_jheightsize[x - 1] * sdp->sd_inptrs;
319 		d = space;
320 		m = do_div(d, sdp->sd_inptrs);
321 
322 		if (d != sdp->sd_jheightsize[x - 1] || m)
323 			break;
324 		sdp->sd_jheightsize[x] = space;
325 	}
326 	sdp->sd_max_jheight = x;
327 	gfs2_assert(sdp, sdp->sd_max_jheight <= GFS2_MAX_META_HEIGHT);
328 
329 	return 0;
330 }
331 
332 /**
333  * gfs2_jindex_hold - Grab a lock on the jindex
334  * @sdp: The GFS2 superblock
335  * @ji_gh: the holder for the jindex glock
336  *
337  * This is very similar to the gfs2_rindex_hold() function, except that
338  * in general we hold the jindex lock for longer periods of time and
339  * we grab it far less frequently (in general) then the rgrp lock.
340  *
341  * Returns: errno
342  */
343 
344 int gfs2_jindex_hold(struct gfs2_sbd *sdp, struct gfs2_holder *ji_gh)
345 {
346 	struct gfs2_inode *dip = GFS2_I(sdp->sd_jindex);
347 	struct qstr name;
348 	char buf[20];
349 	struct gfs2_jdesc *jd;
350 	int error;
351 
352 	name.name = buf;
353 
354 	mutex_lock(&sdp->sd_jindex_mutex);
355 
356 	for (;;) {
357 		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, ji_gh);
358 		if (error)
359 			break;
360 
361 		name.len = sprintf(buf, "journal%u", sdp->sd_journals);
362 		name.hash = gfs2_disk_hash(name.name, name.len);
363 
364 		error = gfs2_dir_search(sdp->sd_jindex, &name, NULL, NULL);
365 		if (error == -ENOENT) {
366 			error = 0;
367 			break;
368 		}
369 
370 		gfs2_glock_dq_uninit(ji_gh);
371 
372 		if (error)
373 			break;
374 
375 		error = -ENOMEM;
376 		jd = kzalloc(sizeof(struct gfs2_jdesc), GFP_KERNEL);
377 		if (!jd)
378 			break;
379 
380 		jd->jd_inode = gfs2_lookupi(sdp->sd_jindex, &name, 1, NULL);
381 		if (!jd->jd_inode || IS_ERR(jd->jd_inode)) {
382 			if (!jd->jd_inode)
383 				error = -ENOENT;
384 			else
385 				error = PTR_ERR(jd->jd_inode);
386 			kfree(jd);
387 			break;
388 		}
389 
390 		spin_lock(&sdp->sd_jindex_spin);
391 		jd->jd_jid = sdp->sd_journals++;
392 		list_add_tail(&jd->jd_list, &sdp->sd_jindex_list);
393 		spin_unlock(&sdp->sd_jindex_spin);
394 	}
395 
396 	mutex_unlock(&sdp->sd_jindex_mutex);
397 
398 	return error;
399 }
400 
401 /**
402  * gfs2_jindex_free - Clear all the journal index information
403  * @sdp: The GFS2 superblock
404  *
405  */
406 
407 void gfs2_jindex_free(struct gfs2_sbd *sdp)
408 {
409 	struct list_head list;
410 	struct gfs2_jdesc *jd;
411 
412 	spin_lock(&sdp->sd_jindex_spin);
413 	list_add(&list, &sdp->sd_jindex_list);
414 	list_del_init(&sdp->sd_jindex_list);
415 	sdp->sd_journals = 0;
416 	spin_unlock(&sdp->sd_jindex_spin);
417 
418 	while (!list_empty(&list)) {
419 		jd = list_entry(list.next, struct gfs2_jdesc, jd_list);
420 		list_del(&jd->jd_list);
421 		iput(jd->jd_inode);
422 		kfree(jd);
423 	}
424 }
425 
426 static struct gfs2_jdesc *jdesc_find_i(struct list_head *head, unsigned int jid)
427 {
428 	struct gfs2_jdesc *jd;
429 	int found = 0;
430 
431 	list_for_each_entry(jd, head, jd_list) {
432 		if (jd->jd_jid == jid) {
433 			found = 1;
434 			break;
435 		}
436 	}
437 
438 	if (!found)
439 		jd = NULL;
440 
441 	return jd;
442 }
443 
444 struct gfs2_jdesc *gfs2_jdesc_find(struct gfs2_sbd *sdp, unsigned int jid)
445 {
446 	struct gfs2_jdesc *jd;
447 
448 	spin_lock(&sdp->sd_jindex_spin);
449 	jd = jdesc_find_i(&sdp->sd_jindex_list, jid);
450 	spin_unlock(&sdp->sd_jindex_spin);
451 
452 	return jd;
453 }
454 
455 void gfs2_jdesc_make_dirty(struct gfs2_sbd *sdp, unsigned int jid)
456 {
457 	struct gfs2_jdesc *jd;
458 
459 	spin_lock(&sdp->sd_jindex_spin);
460 	jd = jdesc_find_i(&sdp->sd_jindex_list, jid);
461 	if (jd)
462 		jd->jd_dirty = 1;
463 	spin_unlock(&sdp->sd_jindex_spin);
464 }
465 
466 struct gfs2_jdesc *gfs2_jdesc_find_dirty(struct gfs2_sbd *sdp)
467 {
468 	struct gfs2_jdesc *jd;
469 	int found = 0;
470 
471 	spin_lock(&sdp->sd_jindex_spin);
472 
473 	list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
474 		if (jd->jd_dirty) {
475 			jd->jd_dirty = 0;
476 			found = 1;
477 			break;
478 		}
479 	}
480 	spin_unlock(&sdp->sd_jindex_spin);
481 
482 	if (!found)
483 		jd = NULL;
484 
485 	return jd;
486 }
487 
488 int gfs2_jdesc_check(struct gfs2_jdesc *jd)
489 {
490 	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
491 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
492 	int ar;
493 	int error;
494 
495 	if (ip->i_di.di_size < (8 << 20) || ip->i_di.di_size > (1 << 30) ||
496 	    (ip->i_di.di_size & (sdp->sd_sb.sb_bsize - 1))) {
497 		gfs2_consist_inode(ip);
498 		return -EIO;
499 	}
500 	jd->jd_blocks = ip->i_di.di_size >> sdp->sd_sb.sb_bsize_shift;
501 
502 	error = gfs2_write_alloc_required(ip, 0, ip->i_di.di_size, &ar);
503 	if (!error && ar) {
504 		gfs2_consist_inode(ip);
505 		error = -EIO;
506 	}
507 
508 	return error;
509 }
510 
511 /**
512  * gfs2_make_fs_rw - Turn a Read-Only FS into a Read-Write one
513  * @sdp: the filesystem
514  *
515  * Returns: errno
516  */
517 
518 int gfs2_make_fs_rw(struct gfs2_sbd *sdp)
519 {
520 	struct gfs2_inode *ip = GFS2_I(sdp->sd_jdesc->jd_inode);
521 	struct gfs2_glock *j_gl = ip->i_gl;
522 	struct gfs2_holder t_gh;
523 	struct gfs2_log_header_host head;
524 	int error;
525 
526 	error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED, 0, &t_gh);
527 	if (error)
528 		return error;
529 
530 	gfs2_meta_cache_flush(ip);
531 	j_gl->gl_ops->go_inval(j_gl, DIO_METADATA);
532 
533 	error = gfs2_find_jhead(sdp->sd_jdesc, &head);
534 	if (error)
535 		goto fail;
536 
537 	if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
538 		gfs2_consist(sdp);
539 		error = -EIO;
540 		goto fail;
541 	}
542 
543 	/*  Initialize some head of the log stuff  */
544 	sdp->sd_log_sequence = head.lh_sequence + 1;
545 	gfs2_log_pointers_init(sdp, head.lh_blkno);
546 
547 	error = gfs2_quota_init(sdp);
548 	if (error)
549 		goto fail;
550 
551 	set_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
552 
553 	gfs2_glock_dq_uninit(&t_gh);
554 
555 	return 0;
556 
557 fail:
558 	t_gh.gh_flags |= GL_NOCACHE;
559 	gfs2_glock_dq_uninit(&t_gh);
560 
561 	return error;
562 }
563 
564 /**
565  * gfs2_make_fs_ro - Turn a Read-Write FS into a Read-Only one
566  * @sdp: the filesystem
567  *
568  * Returns: errno
569  */
570 
571 int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
572 {
573 	struct gfs2_holder t_gh;
574 	int error;
575 
576 	gfs2_quota_sync(sdp);
577 	gfs2_statfs_sync(sdp);
578 
579 	error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED, GL_NOCACHE,
580 				   &t_gh);
581 	if (error && !test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
582 		return error;
583 
584 	gfs2_meta_syncfs(sdp);
585 	gfs2_log_shutdown(sdp);
586 
587 	clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
588 
589 	if (t_gh.gh_gl)
590 		gfs2_glock_dq_uninit(&t_gh);
591 
592 	gfs2_quota_cleanup(sdp);
593 
594 	return error;
595 }
596 
597 int gfs2_statfs_init(struct gfs2_sbd *sdp)
598 {
599 	struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
600 	struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
601 	struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
602 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
603 	struct buffer_head *m_bh, *l_bh;
604 	struct gfs2_holder gh;
605 	int error;
606 
607 	error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, GL_NOCACHE,
608 				   &gh);
609 	if (error)
610 		return error;
611 
612 	error = gfs2_meta_inode_buffer(m_ip, &m_bh);
613 	if (error)
614 		goto out;
615 
616 	if (sdp->sd_args.ar_spectator) {
617 		spin_lock(&sdp->sd_statfs_spin);
618 		gfs2_statfs_change_in(m_sc, m_bh->b_data +
619 				      sizeof(struct gfs2_dinode));
620 		spin_unlock(&sdp->sd_statfs_spin);
621 	} else {
622 		error = gfs2_meta_inode_buffer(l_ip, &l_bh);
623 		if (error)
624 			goto out_m_bh;
625 
626 		spin_lock(&sdp->sd_statfs_spin);
627 		gfs2_statfs_change_in(m_sc, m_bh->b_data +
628 				      sizeof(struct gfs2_dinode));
629 		gfs2_statfs_change_in(l_sc, l_bh->b_data +
630 				      sizeof(struct gfs2_dinode));
631 		spin_unlock(&sdp->sd_statfs_spin);
632 
633 		brelse(l_bh);
634 	}
635 
636 out_m_bh:
637 	brelse(m_bh);
638 out:
639 	gfs2_glock_dq_uninit(&gh);
640 	return 0;
641 }
642 
643 void gfs2_statfs_change(struct gfs2_sbd *sdp, s64 total, s64 free,
644 			s64 dinodes)
645 {
646 	struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
647 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
648 	struct buffer_head *l_bh;
649 	int error;
650 
651 	error = gfs2_meta_inode_buffer(l_ip, &l_bh);
652 	if (error)
653 		return;
654 
655 	mutex_lock(&sdp->sd_statfs_mutex);
656 	gfs2_trans_add_bh(l_ip->i_gl, l_bh, 1);
657 	mutex_unlock(&sdp->sd_statfs_mutex);
658 
659 	spin_lock(&sdp->sd_statfs_spin);
660 	l_sc->sc_total += total;
661 	l_sc->sc_free += free;
662 	l_sc->sc_dinodes += dinodes;
663 	gfs2_statfs_change_out(l_sc, l_bh->b_data + sizeof(struct gfs2_dinode));
664 	spin_unlock(&sdp->sd_statfs_spin);
665 
666 	brelse(l_bh);
667 }
668 
669 int gfs2_statfs_sync(struct gfs2_sbd *sdp)
670 {
671 	struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
672 	struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
673 	struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
674 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
675 	struct gfs2_holder gh;
676 	struct buffer_head *m_bh, *l_bh;
677 	int error;
678 
679 	error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, GL_NOCACHE,
680 				   &gh);
681 	if (error)
682 		return error;
683 
684 	error = gfs2_meta_inode_buffer(m_ip, &m_bh);
685 	if (error)
686 		goto out;
687 
688 	spin_lock(&sdp->sd_statfs_spin);
689 	gfs2_statfs_change_in(m_sc, m_bh->b_data +
690 			      sizeof(struct gfs2_dinode));
691 	if (!l_sc->sc_total && !l_sc->sc_free && !l_sc->sc_dinodes) {
692 		spin_unlock(&sdp->sd_statfs_spin);
693 		goto out_bh;
694 	}
695 	spin_unlock(&sdp->sd_statfs_spin);
696 
697 	error = gfs2_meta_inode_buffer(l_ip, &l_bh);
698 	if (error)
699 		goto out_bh;
700 
701 	error = gfs2_trans_begin(sdp, 2 * RES_DINODE, 0);
702 	if (error)
703 		goto out_bh2;
704 
705 	mutex_lock(&sdp->sd_statfs_mutex);
706 	gfs2_trans_add_bh(l_ip->i_gl, l_bh, 1);
707 	mutex_unlock(&sdp->sd_statfs_mutex);
708 
709 	spin_lock(&sdp->sd_statfs_spin);
710 	m_sc->sc_total += l_sc->sc_total;
711 	m_sc->sc_free += l_sc->sc_free;
712 	m_sc->sc_dinodes += l_sc->sc_dinodes;
713 	memset(l_sc, 0, sizeof(struct gfs2_statfs_change));
714 	memset(l_bh->b_data + sizeof(struct gfs2_dinode),
715 	       0, sizeof(struct gfs2_statfs_change));
716 	spin_unlock(&sdp->sd_statfs_spin);
717 
718 	gfs2_trans_add_bh(m_ip->i_gl, m_bh, 1);
719 	gfs2_statfs_change_out(m_sc, m_bh->b_data + sizeof(struct gfs2_dinode));
720 
721 	gfs2_trans_end(sdp);
722 
723 out_bh2:
724 	brelse(l_bh);
725 out_bh:
726 	brelse(m_bh);
727 out:
728 	gfs2_glock_dq_uninit(&gh);
729 	return error;
730 }
731 
732 /**
733  * gfs2_statfs_i - Do a statfs
734  * @sdp: the filesystem
735  * @sg: the sg structure
736  *
737  * Returns: errno
738  */
739 
740 int gfs2_statfs_i(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
741 {
742 	struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
743 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
744 
745 	spin_lock(&sdp->sd_statfs_spin);
746 
747 	*sc = *m_sc;
748 	sc->sc_total += l_sc->sc_total;
749 	sc->sc_free += l_sc->sc_free;
750 	sc->sc_dinodes += l_sc->sc_dinodes;
751 
752 	spin_unlock(&sdp->sd_statfs_spin);
753 
754 	if (sc->sc_free < 0)
755 		sc->sc_free = 0;
756 	if (sc->sc_free > sc->sc_total)
757 		sc->sc_free = sc->sc_total;
758 	if (sc->sc_dinodes < 0)
759 		sc->sc_dinodes = 0;
760 
761 	return 0;
762 }
763 
764 /**
765  * statfs_fill - fill in the sg for a given RG
766  * @rgd: the RG
767  * @sc: the sc structure
768  *
769  * Returns: 0 on success, -ESTALE if the LVB is invalid
770  */
771 
772 static int statfs_slow_fill(struct gfs2_rgrpd *rgd,
773 			    struct gfs2_statfs_change_host *sc)
774 {
775 	gfs2_rgrp_verify(rgd);
776 	sc->sc_total += rgd->rd_ri.ri_data;
777 	sc->sc_free += rgd->rd_rg.rg_free;
778 	sc->sc_dinodes += rgd->rd_rg.rg_dinodes;
779 	return 0;
780 }
781 
782 /**
783  * gfs2_statfs_slow - Stat a filesystem using asynchronous locking
784  * @sdp: the filesystem
785  * @sc: the sc info that will be returned
786  *
787  * Any error (other than a signal) will cause this routine to fall back
788  * to the synchronous version.
789  *
790  * FIXME: This really shouldn't busy wait like this.
791  *
792  * Returns: errno
793  */
794 
795 int gfs2_statfs_slow(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
796 {
797 	struct gfs2_holder ri_gh;
798 	struct gfs2_rgrpd *rgd_next;
799 	struct gfs2_holder *gha, *gh;
800 	unsigned int slots = 64;
801 	unsigned int x;
802 	int done;
803 	int error = 0, err;
804 
805 	memset(sc, 0, sizeof(struct gfs2_statfs_change_host));
806 	gha = kcalloc(slots, sizeof(struct gfs2_holder), GFP_KERNEL);
807 	if (!gha)
808 		return -ENOMEM;
809 
810 	error = gfs2_rindex_hold(sdp, &ri_gh);
811 	if (error)
812 		goto out;
813 
814 	rgd_next = gfs2_rgrpd_get_first(sdp);
815 
816 	for (;;) {
817 		done = 1;
818 
819 		for (x = 0; x < slots; x++) {
820 			gh = gha + x;
821 
822 			if (gh->gh_gl && gfs2_glock_poll(gh)) {
823 				err = gfs2_glock_wait(gh);
824 				if (err) {
825 					gfs2_holder_uninit(gh);
826 					error = err;
827 				} else {
828 					if (!error)
829 						error = statfs_slow_fill(
830 							gh->gh_gl->gl_object, sc);
831 					gfs2_glock_dq_uninit(gh);
832 				}
833 			}
834 
835 			if (gh->gh_gl)
836 				done = 0;
837 			else if (rgd_next && !error) {
838 				error = gfs2_glock_nq_init(rgd_next->rd_gl,
839 							   LM_ST_SHARED,
840 							   GL_ASYNC,
841 							   gh);
842 				rgd_next = gfs2_rgrpd_get_next(rgd_next);
843 				done = 0;
844 			}
845 
846 			if (signal_pending(current))
847 				error = -ERESTARTSYS;
848 		}
849 
850 		if (done)
851 			break;
852 
853 		yield();
854 	}
855 
856 	gfs2_glock_dq_uninit(&ri_gh);
857 
858 out:
859 	kfree(gha);
860 	return error;
861 }
862 
863 struct lfcc {
864 	struct list_head list;
865 	struct gfs2_holder gh;
866 };
867 
868 /**
869  * gfs2_lock_fs_check_clean - Stop all writes to the FS and check that all
870  *                            journals are clean
871  * @sdp: the file system
872  * @state: the state to put the transaction lock into
873  * @t_gh: the hold on the transaction lock
874  *
875  * Returns: errno
876  */
877 
878 static int gfs2_lock_fs_check_clean(struct gfs2_sbd *sdp,
879 				    struct gfs2_holder *t_gh)
880 {
881 	struct gfs2_inode *ip;
882 	struct gfs2_holder ji_gh;
883 	struct gfs2_jdesc *jd;
884 	struct lfcc *lfcc;
885 	LIST_HEAD(list);
886 	struct gfs2_log_header_host lh;
887 	int error;
888 
889 	error = gfs2_jindex_hold(sdp, &ji_gh);
890 	if (error)
891 		return error;
892 
893 	list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
894 		lfcc = kmalloc(sizeof(struct lfcc), GFP_KERNEL);
895 		if (!lfcc) {
896 			error = -ENOMEM;
897 			goto out;
898 		}
899 		ip = GFS2_I(jd->jd_inode);
900 		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &lfcc->gh);
901 		if (error) {
902 			kfree(lfcc);
903 			goto out;
904 		}
905 		list_add(&lfcc->list, &list);
906 	}
907 
908 	error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_DEFERRED,
909 			       LM_FLAG_PRIORITY | GL_NOCACHE,
910 			       t_gh);
911 
912 	list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
913 		error = gfs2_jdesc_check(jd);
914 		if (error)
915 			break;
916 		error = gfs2_find_jhead(jd, &lh);
917 		if (error)
918 			break;
919 		if (!(lh.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
920 			error = -EBUSY;
921 			break;
922 		}
923 	}
924 
925 	if (error)
926 		gfs2_glock_dq_uninit(t_gh);
927 
928 out:
929 	while (!list_empty(&list)) {
930 		lfcc = list_entry(list.next, struct lfcc, list);
931 		list_del(&lfcc->list);
932 		gfs2_glock_dq_uninit(&lfcc->gh);
933 		kfree(lfcc);
934 	}
935 	gfs2_glock_dq_uninit(&ji_gh);
936 	return error;
937 }
938 
939 /**
940  * gfs2_freeze_fs - freezes the file system
941  * @sdp: the file system
942  *
943  * This function flushes data and meta data for all machines by
944  * aquiring the transaction log exclusively.  All journals are
945  * ensured to be in a clean state as well.
946  *
947  * Returns: errno
948  */
949 
950 int gfs2_freeze_fs(struct gfs2_sbd *sdp)
951 {
952 	int error = 0;
953 
954 	mutex_lock(&sdp->sd_freeze_lock);
955 
956 	if (!sdp->sd_freeze_count++) {
957 		error = gfs2_lock_fs_check_clean(sdp, &sdp->sd_freeze_gh);
958 		if (error)
959 			sdp->sd_freeze_count--;
960 	}
961 
962 	mutex_unlock(&sdp->sd_freeze_lock);
963 
964 	return error;
965 }
966 
967 /**
968  * gfs2_unfreeze_fs - unfreezes the file system
969  * @sdp: the file system
970  *
971  * This function allows the file system to proceed by unlocking
972  * the exclusively held transaction lock.  Other GFS2 nodes are
973  * now free to acquire the lock shared and go on with their lives.
974  *
975  */
976 
977 void gfs2_unfreeze_fs(struct gfs2_sbd *sdp)
978 {
979 	mutex_lock(&sdp->sd_freeze_lock);
980 
981 	if (sdp->sd_freeze_count && !--sdp->sd_freeze_count)
982 		gfs2_glock_dq_uninit(&sdp->sd_freeze_gh);
983 
984 	mutex_unlock(&sdp->sd_freeze_lock);
985 }
986 
987