xref: /openbmc/linux/fs/gfs2/super.c (revision 643d1f7f)
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2007 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_demote_secs = 300;
55 	gt->gt_incore_log_blocks = 1024;
56 	gt->gt_log_flush_secs = 60;
57 	gt->gt_recoverd_secs = 60;
58 	gt->gt_logd_secs = 1;
59 	gt->gt_quotad_secs = 5;
60 	gt->gt_quota_simul_sync = 64;
61 	gt->gt_quota_warn_period = 10;
62 	gt->gt_quota_scale_num = 1;
63 	gt->gt_quota_scale_den = 1;
64 	gt->gt_quota_cache_secs = 300;
65 	gt->gt_quota_quantum = 60;
66 	gt->gt_atime_quantum = 3600;
67 	gt->gt_new_files_jdata = 0;
68 	gt->gt_new_files_directio = 0;
69 	gt->gt_max_readahead = 1 << 18;
70 	gt->gt_stall_secs = 600;
71 	gt->gt_complain_secs = 10;
72 	gt->gt_statfs_quantum = 30;
73 	gt->gt_statfs_slow = 0;
74 }
75 
76 /**
77  * gfs2_check_sb - Check superblock
78  * @sdp: the filesystem
79  * @sb: The superblock
80  * @silent: Don't print a message if the check fails
81  *
82  * Checks the version code of the FS is one that we understand how to
83  * read and that the sizes of the various on-disk structures have not
84  * changed.
85  */
86 
87 int gfs2_check_sb(struct gfs2_sbd *sdp, struct gfs2_sb_host *sb, int silent)
88 {
89 	unsigned int x;
90 
91 	if (sb->sb_magic != GFS2_MAGIC ||
92 	    sb->sb_type != GFS2_METATYPE_SB) {
93 		if (!silent)
94 			printk(KERN_WARNING "GFS2: not a GFS2 filesystem\n");
95 		return -EINVAL;
96 	}
97 
98 	/*  If format numbers match exactly, we're done.  */
99 
100 	if (sb->sb_fs_format == GFS2_FORMAT_FS &&
101 	    sb->sb_multihost_format == GFS2_FORMAT_MULTI)
102 		return 0;
103 
104 	if (sb->sb_fs_format != GFS2_FORMAT_FS) {
105 		for (x = 0; gfs2_old_fs_formats[x]; x++)
106 			if (gfs2_old_fs_formats[x] == sb->sb_fs_format)
107 				break;
108 
109 		if (!gfs2_old_fs_formats[x]) {
110 			printk(KERN_WARNING
111 			       "GFS2: code version (%u, %u) is incompatible "
112 			       "with ondisk format (%u, %u)\n",
113 			       GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
114 			       sb->sb_fs_format, sb->sb_multihost_format);
115 			printk(KERN_WARNING
116 			       "GFS2: I don't know how to upgrade this FS\n");
117 			return -EINVAL;
118 		}
119 	}
120 
121 	if (sb->sb_multihost_format != GFS2_FORMAT_MULTI) {
122 		for (x = 0; gfs2_old_multihost_formats[x]; x++)
123 			if (gfs2_old_multihost_formats[x] ==
124 			    sb->sb_multihost_format)
125 				break;
126 
127 		if (!gfs2_old_multihost_formats[x]) {
128 			printk(KERN_WARNING
129 			       "GFS2: code version (%u, %u) is incompatible "
130 			       "with ondisk format (%u, %u)\n",
131 			       GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
132 			       sb->sb_fs_format, sb->sb_multihost_format);
133 			printk(KERN_WARNING
134 			       "GFS2: I don't know how to upgrade this FS\n");
135 			return -EINVAL;
136 		}
137 	}
138 
139 	if (!sdp->sd_args.ar_upgrade) {
140 		printk(KERN_WARNING
141 		       "GFS2: code version (%u, %u) is incompatible "
142 		       "with ondisk format (%u, %u)\n",
143 		       GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
144 		       sb->sb_fs_format, sb->sb_multihost_format);
145 		printk(KERN_INFO
146 		       "GFS2: Use the \"upgrade\" mount option to upgrade "
147 		       "the FS\n");
148 		printk(KERN_INFO "GFS2: See the manual for more details\n");
149 		return -EINVAL;
150 	}
151 
152 	return 0;
153 }
154 
155 
156 static void end_bio_io_page(struct bio *bio, int error)
157 {
158 	struct page *page = bio->bi_private;
159 
160 	if (!error)
161 		SetPageUptodate(page);
162 	else
163 		printk(KERN_WARNING "gfs2: error %d reading superblock\n", error);
164 	unlock_page(page);
165 }
166 
167 static void gfs2_sb_in(struct gfs2_sb_host *sb, const void *buf)
168 {
169 	const struct gfs2_sb *str = buf;
170 
171 	sb->sb_magic = be32_to_cpu(str->sb_header.mh_magic);
172 	sb->sb_type = be32_to_cpu(str->sb_header.mh_type);
173 	sb->sb_format = be32_to_cpu(str->sb_header.mh_format);
174 	sb->sb_fs_format = be32_to_cpu(str->sb_fs_format);
175 	sb->sb_multihost_format = be32_to_cpu(str->sb_multihost_format);
176 	sb->sb_bsize = be32_to_cpu(str->sb_bsize);
177 	sb->sb_bsize_shift = be32_to_cpu(str->sb_bsize_shift);
178 	sb->sb_master_dir.no_addr = be64_to_cpu(str->sb_master_dir.no_addr);
179 	sb->sb_master_dir.no_formal_ino = be64_to_cpu(str->sb_master_dir.no_formal_ino);
180 	sb->sb_root_dir.no_addr = be64_to_cpu(str->sb_root_dir.no_addr);
181 	sb->sb_root_dir.no_formal_ino = be64_to_cpu(str->sb_root_dir.no_formal_ino);
182 
183 	memcpy(sb->sb_lockproto, str->sb_lockproto, GFS2_LOCKNAME_LEN);
184 	memcpy(sb->sb_locktable, str->sb_locktable, GFS2_LOCKNAME_LEN);
185 }
186 
187 /**
188  * gfs2_read_super - Read the gfs2 super block from disk
189  * @sdp: The GFS2 super block
190  * @sector: The location of the super block
191  * @error: The error code to return
192  *
193  * This uses the bio functions to read the super block from disk
194  * because we want to be 100% sure that we never read cached data.
195  * A super block is read twice only during each GFS2 mount and is
196  * never written to by the filesystem. The first time its read no
197  * locks are held, and the only details which are looked at are those
198  * relating to the locking protocol. Once locking is up and working,
199  * the sb is read again under the lock to establish the location of
200  * the master directory (contains pointers to journals etc) and the
201  * root directory.
202  *
203  * Returns: 0 on success or error
204  */
205 
206 int gfs2_read_super(struct gfs2_sbd *sdp, sector_t sector)
207 {
208 	struct super_block *sb = sdp->sd_vfs;
209 	struct gfs2_sb *p;
210 	struct page *page;
211 	struct bio *bio;
212 
213 	page = alloc_page(GFP_KERNEL);
214 	if (unlikely(!page))
215 		return -ENOBUFS;
216 
217 	ClearPageUptodate(page);
218 	ClearPageDirty(page);
219 	lock_page(page);
220 
221 	bio = bio_alloc(GFP_KERNEL, 1);
222 	if (unlikely(!bio)) {
223 		__free_page(page);
224 		return -ENOBUFS;
225 	}
226 
227 	bio->bi_sector = sector * (sb->s_blocksize >> 9);
228 	bio->bi_bdev = sb->s_bdev;
229 	bio_add_page(bio, page, PAGE_SIZE, 0);
230 
231 	bio->bi_end_io = end_bio_io_page;
232 	bio->bi_private = page;
233 	submit_bio(READ_SYNC | (1 << BIO_RW_META), bio);
234 	wait_on_page_locked(page);
235 	bio_put(bio);
236 	if (!PageUptodate(page)) {
237 		__free_page(page);
238 		return -EIO;
239 	}
240 	p = kmap(page);
241 	gfs2_sb_in(&sdp->sd_sb, p);
242 	kunmap(page);
243 	__free_page(page);
244 	return 0;
245 }
246 
247 /**
248  * gfs2_read_sb - Read super block
249  * @sdp: The GFS2 superblock
250  * @gl: the glock for the superblock (assumed to be held)
251  * @silent: Don't print message if mount fails
252  *
253  */
254 
255 int gfs2_read_sb(struct gfs2_sbd *sdp, struct gfs2_glock *gl, int silent)
256 {
257 	u32 hash_blocks, ind_blocks, leaf_blocks;
258 	u32 tmp_blocks;
259 	unsigned int x;
260 	int error;
261 
262 	error = gfs2_read_super(sdp, GFS2_SB_ADDR >> sdp->sd_fsb2bb_shift);
263 	if (error) {
264 		if (!silent)
265 			fs_err(sdp, "can't read superblock\n");
266 		return error;
267 	}
268 
269 	error = gfs2_check_sb(sdp, &sdp->sd_sb, silent);
270 	if (error)
271 		return error;
272 
273 	sdp->sd_fsb2bb_shift = sdp->sd_sb.sb_bsize_shift -
274 			       GFS2_BASIC_BLOCK_SHIFT;
275 	sdp->sd_fsb2bb = 1 << sdp->sd_fsb2bb_shift;
276 	sdp->sd_diptrs = (sdp->sd_sb.sb_bsize -
277 			  sizeof(struct gfs2_dinode)) / sizeof(u64);
278 	sdp->sd_inptrs = (sdp->sd_sb.sb_bsize -
279 			  sizeof(struct gfs2_meta_header)) / sizeof(u64);
280 	sdp->sd_jbsize = sdp->sd_sb.sb_bsize - sizeof(struct gfs2_meta_header);
281 	sdp->sd_hash_bsize = sdp->sd_sb.sb_bsize / 2;
282 	sdp->sd_hash_bsize_shift = sdp->sd_sb.sb_bsize_shift - 1;
283 	sdp->sd_hash_ptrs = sdp->sd_hash_bsize / sizeof(u64);
284 	sdp->sd_qc_per_block = (sdp->sd_sb.sb_bsize -
285 				sizeof(struct gfs2_meta_header)) /
286 			        sizeof(struct gfs2_quota_change);
287 
288 	/* Compute maximum reservation required to add a entry to a directory */
289 
290 	hash_blocks = DIV_ROUND_UP(sizeof(u64) * (1 << GFS2_DIR_MAX_DEPTH),
291 			     sdp->sd_jbsize);
292 
293 	ind_blocks = 0;
294 	for (tmp_blocks = hash_blocks; tmp_blocks > sdp->sd_diptrs;) {
295 		tmp_blocks = DIV_ROUND_UP(tmp_blocks, sdp->sd_inptrs);
296 		ind_blocks += tmp_blocks;
297 	}
298 
299 	leaf_blocks = 2 + GFS2_DIR_MAX_DEPTH;
300 
301 	sdp->sd_max_dirres = hash_blocks + ind_blocks + leaf_blocks;
302 
303 	sdp->sd_heightsize[0] = sdp->sd_sb.sb_bsize -
304 				sizeof(struct gfs2_dinode);
305 	sdp->sd_heightsize[1] = sdp->sd_sb.sb_bsize * sdp->sd_diptrs;
306 	for (x = 2;; x++) {
307 		u64 space, d;
308 		u32 m;
309 
310 		space = sdp->sd_heightsize[x - 1] * sdp->sd_inptrs;
311 		d = space;
312 		m = do_div(d, sdp->sd_inptrs);
313 
314 		if (d != sdp->sd_heightsize[x - 1] || m)
315 			break;
316 		sdp->sd_heightsize[x] = space;
317 	}
318 	sdp->sd_max_height = x;
319 	gfs2_assert(sdp, sdp->sd_max_height <= GFS2_MAX_META_HEIGHT);
320 
321 	sdp->sd_jheightsize[0] = sdp->sd_sb.sb_bsize -
322 				 sizeof(struct gfs2_dinode);
323 	sdp->sd_jheightsize[1] = sdp->sd_jbsize * sdp->sd_diptrs;
324 	for (x = 2;; x++) {
325 		u64 space, d;
326 		u32 m;
327 
328 		space = sdp->sd_jheightsize[x - 1] * sdp->sd_inptrs;
329 		d = space;
330 		m = do_div(d, sdp->sd_inptrs);
331 
332 		if (d != sdp->sd_jheightsize[x - 1] || m)
333 			break;
334 		sdp->sd_jheightsize[x] = space;
335 	}
336 	sdp->sd_max_jheight = x;
337 	gfs2_assert(sdp, sdp->sd_max_jheight <= GFS2_MAX_META_HEIGHT);
338 
339 	return 0;
340 }
341 
342 /**
343  * gfs2_jindex_hold - Grab a lock on the jindex
344  * @sdp: The GFS2 superblock
345  * @ji_gh: the holder for the jindex glock
346  *
347  * This is very similar to the gfs2_rindex_hold() function, except that
348  * in general we hold the jindex lock for longer periods of time and
349  * we grab it far less frequently (in general) then the rgrp lock.
350  *
351  * Returns: errno
352  */
353 
354 int gfs2_jindex_hold(struct gfs2_sbd *sdp, struct gfs2_holder *ji_gh)
355 {
356 	struct gfs2_inode *dip = GFS2_I(sdp->sd_jindex);
357 	struct qstr name;
358 	char buf[20];
359 	struct gfs2_jdesc *jd;
360 	int error;
361 
362 	name.name = buf;
363 
364 	mutex_lock(&sdp->sd_jindex_mutex);
365 
366 	for (;;) {
367 		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, ji_gh);
368 		if (error)
369 			break;
370 
371 		name.len = sprintf(buf, "journal%u", sdp->sd_journals);
372 		name.hash = gfs2_disk_hash(name.name, name.len);
373 
374 		error = gfs2_dir_check(sdp->sd_jindex, &name, NULL);
375 		if (error == -ENOENT) {
376 			error = 0;
377 			break;
378 		}
379 
380 		gfs2_glock_dq_uninit(ji_gh);
381 
382 		if (error)
383 			break;
384 
385 		error = -ENOMEM;
386 		jd = kzalloc(sizeof(struct gfs2_jdesc), GFP_KERNEL);
387 		if (!jd)
388 			break;
389 
390 		INIT_LIST_HEAD(&jd->extent_list);
391 		jd->jd_inode = gfs2_lookupi(sdp->sd_jindex, &name, 1, NULL);
392 		if (!jd->jd_inode || IS_ERR(jd->jd_inode)) {
393 			if (!jd->jd_inode)
394 				error = -ENOENT;
395 			else
396 				error = PTR_ERR(jd->jd_inode);
397 			kfree(jd);
398 			break;
399 		}
400 
401 		spin_lock(&sdp->sd_jindex_spin);
402 		jd->jd_jid = sdp->sd_journals++;
403 		list_add_tail(&jd->jd_list, &sdp->sd_jindex_list);
404 		spin_unlock(&sdp->sd_jindex_spin);
405 	}
406 
407 	mutex_unlock(&sdp->sd_jindex_mutex);
408 
409 	return error;
410 }
411 
412 /**
413  * gfs2_jindex_free - Clear all the journal index information
414  * @sdp: The GFS2 superblock
415  *
416  */
417 
418 void gfs2_jindex_free(struct gfs2_sbd *sdp)
419 {
420 	struct list_head list, *head;
421 	struct gfs2_jdesc *jd;
422 	struct gfs2_journal_extent *jext;
423 
424 	spin_lock(&sdp->sd_jindex_spin);
425 	list_add(&list, &sdp->sd_jindex_list);
426 	list_del_init(&sdp->sd_jindex_list);
427 	sdp->sd_journals = 0;
428 	spin_unlock(&sdp->sd_jindex_spin);
429 
430 	while (!list_empty(&list)) {
431 		jd = list_entry(list.next, struct gfs2_jdesc, jd_list);
432 		head = &jd->extent_list;
433 		while (!list_empty(head)) {
434 			jext = list_entry(head->next,
435 					  struct gfs2_journal_extent,
436 					  extent_list);
437 			list_del(&jext->extent_list);
438 			kfree(jext);
439 		}
440 		list_del(&jd->jd_list);
441 		iput(jd->jd_inode);
442 		kfree(jd);
443 	}
444 }
445 
446 static struct gfs2_jdesc *jdesc_find_i(struct list_head *head, unsigned int jid)
447 {
448 	struct gfs2_jdesc *jd;
449 	int found = 0;
450 
451 	list_for_each_entry(jd, head, jd_list) {
452 		if (jd->jd_jid == jid) {
453 			found = 1;
454 			break;
455 		}
456 	}
457 
458 	if (!found)
459 		jd = NULL;
460 
461 	return jd;
462 }
463 
464 struct gfs2_jdesc *gfs2_jdesc_find(struct gfs2_sbd *sdp, unsigned int jid)
465 {
466 	struct gfs2_jdesc *jd;
467 
468 	spin_lock(&sdp->sd_jindex_spin);
469 	jd = jdesc_find_i(&sdp->sd_jindex_list, jid);
470 	spin_unlock(&sdp->sd_jindex_spin);
471 
472 	return jd;
473 }
474 
475 void gfs2_jdesc_make_dirty(struct gfs2_sbd *sdp, unsigned int jid)
476 {
477 	struct gfs2_jdesc *jd;
478 
479 	spin_lock(&sdp->sd_jindex_spin);
480 	jd = jdesc_find_i(&sdp->sd_jindex_list, jid);
481 	if (jd)
482 		jd->jd_dirty = 1;
483 	spin_unlock(&sdp->sd_jindex_spin);
484 }
485 
486 struct gfs2_jdesc *gfs2_jdesc_find_dirty(struct gfs2_sbd *sdp)
487 {
488 	struct gfs2_jdesc *jd;
489 	int found = 0;
490 
491 	spin_lock(&sdp->sd_jindex_spin);
492 
493 	list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
494 		if (jd->jd_dirty) {
495 			jd->jd_dirty = 0;
496 			found = 1;
497 			break;
498 		}
499 	}
500 	spin_unlock(&sdp->sd_jindex_spin);
501 
502 	if (!found)
503 		jd = NULL;
504 
505 	return jd;
506 }
507 
508 int gfs2_jdesc_check(struct gfs2_jdesc *jd)
509 {
510 	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
511 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
512 	int ar;
513 	int error;
514 
515 	if (ip->i_di.di_size < (8 << 20) || ip->i_di.di_size > (1 << 30) ||
516 	    (ip->i_di.di_size & (sdp->sd_sb.sb_bsize - 1))) {
517 		gfs2_consist_inode(ip);
518 		return -EIO;
519 	}
520 	jd->jd_blocks = ip->i_di.di_size >> sdp->sd_sb.sb_bsize_shift;
521 
522 	error = gfs2_write_alloc_required(ip, 0, ip->i_di.di_size, &ar);
523 	if (!error && ar) {
524 		gfs2_consist_inode(ip);
525 		error = -EIO;
526 	}
527 
528 	return error;
529 }
530 
531 /**
532  * gfs2_make_fs_rw - Turn a Read-Only FS into a Read-Write one
533  * @sdp: the filesystem
534  *
535  * Returns: errno
536  */
537 
538 int gfs2_make_fs_rw(struct gfs2_sbd *sdp)
539 {
540 	struct gfs2_inode *ip = GFS2_I(sdp->sd_jdesc->jd_inode);
541 	struct gfs2_glock *j_gl = ip->i_gl;
542 	struct gfs2_holder t_gh;
543 	struct gfs2_log_header_host head;
544 	int error;
545 
546 	error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED, 0, &t_gh);
547 	if (error)
548 		return error;
549 
550 	j_gl->gl_ops->go_inval(j_gl, DIO_METADATA);
551 
552 	error = gfs2_find_jhead(sdp->sd_jdesc, &head);
553 	if (error)
554 		goto fail;
555 
556 	if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
557 		gfs2_consist(sdp);
558 		error = -EIO;
559 		goto fail;
560 	}
561 
562 	/*  Initialize some head of the log stuff  */
563 	sdp->sd_log_sequence = head.lh_sequence + 1;
564 	gfs2_log_pointers_init(sdp, head.lh_blkno);
565 
566 	error = gfs2_quota_init(sdp);
567 	if (error)
568 		goto fail;
569 
570 	set_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
571 
572 	gfs2_glock_dq_uninit(&t_gh);
573 
574 	return 0;
575 
576 fail:
577 	t_gh.gh_flags |= GL_NOCACHE;
578 	gfs2_glock_dq_uninit(&t_gh);
579 
580 	return error;
581 }
582 
583 /**
584  * gfs2_make_fs_ro - Turn a Read-Write FS into a Read-Only one
585  * @sdp: the filesystem
586  *
587  * Returns: errno
588  */
589 
590 int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
591 {
592 	struct gfs2_holder t_gh;
593 	int error;
594 
595 	gfs2_quota_sync(sdp);
596 	gfs2_statfs_sync(sdp);
597 
598 	error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED, GL_NOCACHE,
599 				   &t_gh);
600 	if (error && !test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
601 		return error;
602 
603 	gfs2_meta_syncfs(sdp);
604 	gfs2_log_shutdown(sdp);
605 
606 	clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
607 
608 	if (t_gh.gh_gl)
609 		gfs2_glock_dq_uninit(&t_gh);
610 
611 	gfs2_quota_cleanup(sdp);
612 
613 	return error;
614 }
615 
616 static void gfs2_statfs_change_in(struct gfs2_statfs_change_host *sc, const void *buf)
617 {
618 	const struct gfs2_statfs_change *str = buf;
619 
620 	sc->sc_total = be64_to_cpu(str->sc_total);
621 	sc->sc_free = be64_to_cpu(str->sc_free);
622 	sc->sc_dinodes = be64_to_cpu(str->sc_dinodes);
623 }
624 
625 static void gfs2_statfs_change_out(const struct gfs2_statfs_change_host *sc, void *buf)
626 {
627 	struct gfs2_statfs_change *str = buf;
628 
629 	str->sc_total = cpu_to_be64(sc->sc_total);
630 	str->sc_free = cpu_to_be64(sc->sc_free);
631 	str->sc_dinodes = cpu_to_be64(sc->sc_dinodes);
632 }
633 
634 int gfs2_statfs_init(struct gfs2_sbd *sdp)
635 {
636 	struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
637 	struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
638 	struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
639 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
640 	struct buffer_head *m_bh, *l_bh;
641 	struct gfs2_holder gh;
642 	int error;
643 
644 	error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, GL_NOCACHE,
645 				   &gh);
646 	if (error)
647 		return error;
648 
649 	error = gfs2_meta_inode_buffer(m_ip, &m_bh);
650 	if (error)
651 		goto out;
652 
653 	if (sdp->sd_args.ar_spectator) {
654 		spin_lock(&sdp->sd_statfs_spin);
655 		gfs2_statfs_change_in(m_sc, m_bh->b_data +
656 				      sizeof(struct gfs2_dinode));
657 		spin_unlock(&sdp->sd_statfs_spin);
658 	} else {
659 		error = gfs2_meta_inode_buffer(l_ip, &l_bh);
660 		if (error)
661 			goto out_m_bh;
662 
663 		spin_lock(&sdp->sd_statfs_spin);
664 		gfs2_statfs_change_in(m_sc, m_bh->b_data +
665 				      sizeof(struct gfs2_dinode));
666 		gfs2_statfs_change_in(l_sc, l_bh->b_data +
667 				      sizeof(struct gfs2_dinode));
668 		spin_unlock(&sdp->sd_statfs_spin);
669 
670 		brelse(l_bh);
671 	}
672 
673 out_m_bh:
674 	brelse(m_bh);
675 out:
676 	gfs2_glock_dq_uninit(&gh);
677 	return 0;
678 }
679 
680 void gfs2_statfs_change(struct gfs2_sbd *sdp, s64 total, s64 free,
681 			s64 dinodes)
682 {
683 	struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
684 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
685 	struct buffer_head *l_bh;
686 	int error;
687 
688 	error = gfs2_meta_inode_buffer(l_ip, &l_bh);
689 	if (error)
690 		return;
691 
692 	gfs2_trans_add_bh(l_ip->i_gl, l_bh, 1);
693 
694 	spin_lock(&sdp->sd_statfs_spin);
695 	l_sc->sc_total += total;
696 	l_sc->sc_free += free;
697 	l_sc->sc_dinodes += dinodes;
698 	gfs2_statfs_change_out(l_sc, l_bh->b_data + sizeof(struct gfs2_dinode));
699 	spin_unlock(&sdp->sd_statfs_spin);
700 
701 	brelse(l_bh);
702 }
703 
704 int gfs2_statfs_sync(struct gfs2_sbd *sdp)
705 {
706 	struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
707 	struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
708 	struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
709 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
710 	struct gfs2_holder gh;
711 	struct buffer_head *m_bh, *l_bh;
712 	int error;
713 
714 	error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, GL_NOCACHE,
715 				   &gh);
716 	if (error)
717 		return error;
718 
719 	error = gfs2_meta_inode_buffer(m_ip, &m_bh);
720 	if (error)
721 		goto out;
722 
723 	spin_lock(&sdp->sd_statfs_spin);
724 	gfs2_statfs_change_in(m_sc, m_bh->b_data +
725 			      sizeof(struct gfs2_dinode));
726 	if (!l_sc->sc_total && !l_sc->sc_free && !l_sc->sc_dinodes) {
727 		spin_unlock(&sdp->sd_statfs_spin);
728 		goto out_bh;
729 	}
730 	spin_unlock(&sdp->sd_statfs_spin);
731 
732 	error = gfs2_meta_inode_buffer(l_ip, &l_bh);
733 	if (error)
734 		goto out_bh;
735 
736 	error = gfs2_trans_begin(sdp, 2 * RES_DINODE, 0);
737 	if (error)
738 		goto out_bh2;
739 
740 	gfs2_trans_add_bh(l_ip->i_gl, l_bh, 1);
741 
742 	spin_lock(&sdp->sd_statfs_spin);
743 	m_sc->sc_total += l_sc->sc_total;
744 	m_sc->sc_free += l_sc->sc_free;
745 	m_sc->sc_dinodes += l_sc->sc_dinodes;
746 	memset(l_sc, 0, sizeof(struct gfs2_statfs_change));
747 	memset(l_bh->b_data + sizeof(struct gfs2_dinode),
748 	       0, sizeof(struct gfs2_statfs_change));
749 	spin_unlock(&sdp->sd_statfs_spin);
750 
751 	gfs2_trans_add_bh(m_ip->i_gl, m_bh, 1);
752 	gfs2_statfs_change_out(m_sc, m_bh->b_data + sizeof(struct gfs2_dinode));
753 
754 	gfs2_trans_end(sdp);
755 
756 out_bh2:
757 	brelse(l_bh);
758 out_bh:
759 	brelse(m_bh);
760 out:
761 	gfs2_glock_dq_uninit(&gh);
762 	return error;
763 }
764 
765 /**
766  * gfs2_statfs_i - Do a statfs
767  * @sdp: the filesystem
768  * @sg: the sg structure
769  *
770  * Returns: errno
771  */
772 
773 int gfs2_statfs_i(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
774 {
775 	struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
776 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
777 
778 	spin_lock(&sdp->sd_statfs_spin);
779 
780 	*sc = *m_sc;
781 	sc->sc_total += l_sc->sc_total;
782 	sc->sc_free += l_sc->sc_free;
783 	sc->sc_dinodes += l_sc->sc_dinodes;
784 
785 	spin_unlock(&sdp->sd_statfs_spin);
786 
787 	if (sc->sc_free < 0)
788 		sc->sc_free = 0;
789 	if (sc->sc_free > sc->sc_total)
790 		sc->sc_free = sc->sc_total;
791 	if (sc->sc_dinodes < 0)
792 		sc->sc_dinodes = 0;
793 
794 	return 0;
795 }
796 
797 /**
798  * statfs_fill - fill in the sg for a given RG
799  * @rgd: the RG
800  * @sc: the sc structure
801  *
802  * Returns: 0 on success, -ESTALE if the LVB is invalid
803  */
804 
805 static int statfs_slow_fill(struct gfs2_rgrpd *rgd,
806 			    struct gfs2_statfs_change_host *sc)
807 {
808 	gfs2_rgrp_verify(rgd);
809 	sc->sc_total += rgd->rd_data;
810 	sc->sc_free += rgd->rd_rg.rg_free;
811 	sc->sc_dinodes += rgd->rd_rg.rg_dinodes;
812 	return 0;
813 }
814 
815 /**
816  * gfs2_statfs_slow - Stat a filesystem using asynchronous locking
817  * @sdp: the filesystem
818  * @sc: the sc info that will be returned
819  *
820  * Any error (other than a signal) will cause this routine to fall back
821  * to the synchronous version.
822  *
823  * FIXME: This really shouldn't busy wait like this.
824  *
825  * Returns: errno
826  */
827 
828 int gfs2_statfs_slow(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
829 {
830 	struct gfs2_holder ri_gh;
831 	struct gfs2_rgrpd *rgd_next;
832 	struct gfs2_holder *gha, *gh;
833 	unsigned int slots = 64;
834 	unsigned int x;
835 	int done;
836 	int error = 0, err;
837 
838 	memset(sc, 0, sizeof(struct gfs2_statfs_change_host));
839 	gha = kcalloc(slots, sizeof(struct gfs2_holder), GFP_KERNEL);
840 	if (!gha)
841 		return -ENOMEM;
842 
843 	error = gfs2_rindex_hold(sdp, &ri_gh);
844 	if (error)
845 		goto out;
846 
847 	rgd_next = gfs2_rgrpd_get_first(sdp);
848 
849 	for (;;) {
850 		done = 1;
851 
852 		for (x = 0; x < slots; x++) {
853 			gh = gha + x;
854 
855 			if (gh->gh_gl && gfs2_glock_poll(gh)) {
856 				err = gfs2_glock_wait(gh);
857 				if (err) {
858 					gfs2_holder_uninit(gh);
859 					error = err;
860 				} else {
861 					if (!error)
862 						error = statfs_slow_fill(
863 							gh->gh_gl->gl_object, sc);
864 					gfs2_glock_dq_uninit(gh);
865 				}
866 			}
867 
868 			if (gh->gh_gl)
869 				done = 0;
870 			else if (rgd_next && !error) {
871 				error = gfs2_glock_nq_init(rgd_next->rd_gl,
872 							   LM_ST_SHARED,
873 							   GL_ASYNC,
874 							   gh);
875 				rgd_next = gfs2_rgrpd_get_next(rgd_next);
876 				done = 0;
877 			}
878 
879 			if (signal_pending(current))
880 				error = -ERESTARTSYS;
881 		}
882 
883 		if (done)
884 			break;
885 
886 		yield();
887 	}
888 
889 	gfs2_glock_dq_uninit(&ri_gh);
890 
891 out:
892 	kfree(gha);
893 	return error;
894 }
895 
896 struct lfcc {
897 	struct list_head list;
898 	struct gfs2_holder gh;
899 };
900 
901 /**
902  * gfs2_lock_fs_check_clean - Stop all writes to the FS and check that all
903  *                            journals are clean
904  * @sdp: the file system
905  * @state: the state to put the transaction lock into
906  * @t_gh: the hold on the transaction lock
907  *
908  * Returns: errno
909  */
910 
911 static int gfs2_lock_fs_check_clean(struct gfs2_sbd *sdp,
912 				    struct gfs2_holder *t_gh)
913 {
914 	struct gfs2_inode *ip;
915 	struct gfs2_holder ji_gh;
916 	struct gfs2_jdesc *jd;
917 	struct lfcc *lfcc;
918 	LIST_HEAD(list);
919 	struct gfs2_log_header_host lh;
920 	int error;
921 
922 	error = gfs2_jindex_hold(sdp, &ji_gh);
923 	if (error)
924 		return error;
925 
926 	list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
927 		lfcc = kmalloc(sizeof(struct lfcc), GFP_KERNEL);
928 		if (!lfcc) {
929 			error = -ENOMEM;
930 			goto out;
931 		}
932 		ip = GFS2_I(jd->jd_inode);
933 		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &lfcc->gh);
934 		if (error) {
935 			kfree(lfcc);
936 			goto out;
937 		}
938 		list_add(&lfcc->list, &list);
939 	}
940 
941 	error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_DEFERRED,
942 			       LM_FLAG_PRIORITY | GL_NOCACHE,
943 			       t_gh);
944 
945 	list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
946 		error = gfs2_jdesc_check(jd);
947 		if (error)
948 			break;
949 		error = gfs2_find_jhead(jd, &lh);
950 		if (error)
951 			break;
952 		if (!(lh.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
953 			error = -EBUSY;
954 			break;
955 		}
956 	}
957 
958 	if (error)
959 		gfs2_glock_dq_uninit(t_gh);
960 
961 out:
962 	while (!list_empty(&list)) {
963 		lfcc = list_entry(list.next, struct lfcc, list);
964 		list_del(&lfcc->list);
965 		gfs2_glock_dq_uninit(&lfcc->gh);
966 		kfree(lfcc);
967 	}
968 	gfs2_glock_dq_uninit(&ji_gh);
969 	return error;
970 }
971 
972 /**
973  * gfs2_freeze_fs - freezes the file system
974  * @sdp: the file system
975  *
976  * This function flushes data and meta data for all machines by
977  * aquiring the transaction log exclusively.  All journals are
978  * ensured to be in a clean state as well.
979  *
980  * Returns: errno
981  */
982 
983 int gfs2_freeze_fs(struct gfs2_sbd *sdp)
984 {
985 	int error = 0;
986 
987 	mutex_lock(&sdp->sd_freeze_lock);
988 
989 	if (!sdp->sd_freeze_count++) {
990 		error = gfs2_lock_fs_check_clean(sdp, &sdp->sd_freeze_gh);
991 		if (error)
992 			sdp->sd_freeze_count--;
993 	}
994 
995 	mutex_unlock(&sdp->sd_freeze_lock);
996 
997 	return error;
998 }
999 
1000 /**
1001  * gfs2_unfreeze_fs - unfreezes the file system
1002  * @sdp: the file system
1003  *
1004  * This function allows the file system to proceed by unlocking
1005  * the exclusively held transaction lock.  Other GFS2 nodes are
1006  * now free to acquire the lock shared and go on with their lives.
1007  *
1008  */
1009 
1010 void gfs2_unfreeze_fs(struct gfs2_sbd *sdp)
1011 {
1012 	mutex_lock(&sdp->sd_freeze_lock);
1013 
1014 	if (sdp->sd_freeze_count && !--sdp->sd_freeze_count)
1015 		gfs2_glock_dq_uninit(&sdp->sd_freeze_gh);
1016 
1017 	mutex_unlock(&sdp->sd_freeze_lock);
1018 }
1019 
1020