Merge branch 'master' of /home/trondmy/kernel/linux-2.6/ into merge_linus
[linux-2.6] / fs / gfs2 / super.c
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_atomic_write = 4 << 20;
75         gt->gt_max_readahead = 1 << 18;
76         gt->gt_lockdump_size = 131072;
77         gt->gt_stall_secs = 600;
78         gt->gt_complain_secs = 10;
79         gt->gt_reclaim_limit = 5000;
80         gt->gt_entries_per_readdir = 32;
81         gt->gt_prefetch_secs = 10;
82         gt->gt_greedy_default = HZ / 10;
83         gt->gt_greedy_quantum = HZ / 40;
84         gt->gt_greedy_max = HZ / 4;
85         gt->gt_statfs_quantum = 30;
86         gt->gt_statfs_slow = 0;
87 }
88
89 /**
90  * gfs2_check_sb - Check superblock
91  * @sdp: the filesystem
92  * @sb: The superblock
93  * @silent: Don't print a message if the check fails
94  *
95  * Checks the version code of the FS is one that we understand how to
96  * read and that the sizes of the various on-disk structures have not
97  * changed.
98  */
99
100 int gfs2_check_sb(struct gfs2_sbd *sdp, struct gfs2_sb_host *sb, int silent)
101 {
102         unsigned int x;
103
104         if (sb->sb_header.mh_magic != GFS2_MAGIC ||
105             sb->sb_header.mh_type != GFS2_METATYPE_SB) {
106                 if (!silent)
107                         printk(KERN_WARNING "GFS2: not a GFS2 filesystem\n");
108                 return -EINVAL;
109         }
110
111         /*  If format numbers match exactly, we're done.  */
112
113         if (sb->sb_fs_format == GFS2_FORMAT_FS &&
114             sb->sb_multihost_format == GFS2_FORMAT_MULTI)
115                 return 0;
116
117         if (sb->sb_fs_format != GFS2_FORMAT_FS) {
118                 for (x = 0; gfs2_old_fs_formats[x]; x++)
119                         if (gfs2_old_fs_formats[x] == sb->sb_fs_format)
120                                 break;
121
122                 if (!gfs2_old_fs_formats[x]) {
123                         printk(KERN_WARNING
124                                "GFS2: code version (%u, %u) is incompatible "
125                                "with ondisk format (%u, %u)\n",
126                                GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
127                                sb->sb_fs_format, sb->sb_multihost_format);
128                         printk(KERN_WARNING
129                                "GFS2: I don't know how to upgrade this FS\n");
130                         return -EINVAL;
131                 }
132         }
133
134         if (sb->sb_multihost_format != GFS2_FORMAT_MULTI) {
135                 for (x = 0; gfs2_old_multihost_formats[x]; x++)
136                         if (gfs2_old_multihost_formats[x] ==
137                             sb->sb_multihost_format)
138                                 break;
139
140                 if (!gfs2_old_multihost_formats[x]) {
141                         printk(KERN_WARNING
142                                "GFS2: code version (%u, %u) is incompatible "
143                                "with ondisk format (%u, %u)\n",
144                                GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
145                                sb->sb_fs_format, sb->sb_multihost_format);
146                         printk(KERN_WARNING
147                                "GFS2: I don't know how to upgrade this FS\n");
148                         return -EINVAL;
149                 }
150         }
151
152         if (!sdp->sd_args.ar_upgrade) {
153                 printk(KERN_WARNING
154                        "GFS2: code version (%u, %u) is incompatible "
155                        "with ondisk format (%u, %u)\n",
156                        GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
157                        sb->sb_fs_format, sb->sb_multihost_format);
158                 printk(KERN_INFO
159                        "GFS2: Use the \"upgrade\" mount option to upgrade "
160                        "the FS\n");
161                 printk(KERN_INFO "GFS2: See the manual for more details\n");
162                 return -EINVAL;
163         }
164
165         return 0;
166 }
167
168
169 static int end_bio_io_page(struct bio *bio, unsigned int bytes_done, int error)
170 {
171         struct page *page = bio->bi_private;
172         if (bio->bi_size)
173                 return 1;
174
175         if (!error)
176                 SetPageUptodate(page);
177         else
178                 printk(KERN_WARNING "gfs2: error %d reading superblock\n", error);
179         unlock_page(page);
180         return 0;
181 }
182
183 /**
184  * gfs2_read_super - Read the gfs2 super block from disk
185  * @sb: The VFS super block
186  * @sector: The location of the super block
187  *
188  * This uses the bio functions to read the super block from disk
189  * because we want to be 100% sure that we never read cached data.
190  * A super block is read twice only during each GFS2 mount and is
191  * never written to by the filesystem. The first time its read no
192  * locks are held, and the only details which are looked at are those
193  * relating to the locking protocol. Once locking is up and working,
194  * the sb is read again under the lock to establish the location of
195  * the master directory (contains pointers to journals etc) and the
196  * root directory.
197  *
198  * Returns: A page containing the sb or NULL
199  */
200
201 struct page *gfs2_read_super(struct super_block *sb, sector_t sector)
202 {
203         struct page *page;
204         struct bio *bio;
205
206         page = alloc_page(GFP_KERNEL);
207         if (unlikely(!page))
208                 return NULL;
209
210         ClearPageUptodate(page);
211         ClearPageDirty(page);
212         lock_page(page);
213
214         bio = bio_alloc(GFP_KERNEL, 1);
215         if (unlikely(!bio)) {
216                 __free_page(page);
217                 return NULL;
218         }
219
220         bio->bi_sector = sector * (sb->s_blocksize >> 9);
221         bio->bi_bdev = sb->s_bdev;
222         bio_add_page(bio, page, PAGE_SIZE, 0);
223
224         bio->bi_end_io = end_bio_io_page;
225         bio->bi_private = page;
226         submit_bio(READ_SYNC | (1 << BIO_RW_META), bio);
227         wait_on_page_locked(page);
228         bio_put(bio);
229         if (!PageUptodate(page)) {
230                 __free_page(page);
231                 return NULL;
232         }
233         return page;
234 }
235
236 /**
237  * gfs2_read_sb - Read super block
238  * @sdp: The GFS2 superblock
239  * @gl: the glock for the superblock (assumed to be held)
240  * @silent: Don't print message if mount fails
241  *
242  */
243
244 int gfs2_read_sb(struct gfs2_sbd *sdp, struct gfs2_glock *gl, int silent)
245 {
246         u32 hash_blocks, ind_blocks, leaf_blocks;
247         u32 tmp_blocks;
248         unsigned int x;
249         int error;
250         struct page *page;
251         char *sb;
252
253         page = gfs2_read_super(sdp->sd_vfs, GFS2_SB_ADDR >> sdp->sd_fsb2bb_shift);
254         if (!page) {
255                 if (!silent)
256                         fs_err(sdp, "can't read superblock\n");
257                 return -EIO;
258         }
259         sb = kmap(page);
260         gfs2_sb_in(&sdp->sd_sb, sb);
261         kunmap(page);
262         __free_page(page);
263
264         error = gfs2_check_sb(sdp, &sdp->sd_sb, silent);
265         if (error)
266                 return error;
267
268         sdp->sd_fsb2bb_shift = sdp->sd_sb.sb_bsize_shift -
269                                GFS2_BASIC_BLOCK_SHIFT;
270         sdp->sd_fsb2bb = 1 << sdp->sd_fsb2bb_shift;
271         sdp->sd_diptrs = (sdp->sd_sb.sb_bsize -
272                           sizeof(struct gfs2_dinode)) / sizeof(u64);
273         sdp->sd_inptrs = (sdp->sd_sb.sb_bsize -
274                           sizeof(struct gfs2_meta_header)) / sizeof(u64);
275         sdp->sd_jbsize = sdp->sd_sb.sb_bsize - sizeof(struct gfs2_meta_header);
276         sdp->sd_hash_bsize = sdp->sd_sb.sb_bsize / 2;
277         sdp->sd_hash_bsize_shift = sdp->sd_sb.sb_bsize_shift - 1;
278         sdp->sd_hash_ptrs = sdp->sd_hash_bsize / sizeof(u64);
279         sdp->sd_qc_per_block = (sdp->sd_sb.sb_bsize -
280                                 sizeof(struct gfs2_meta_header)) /
281                                 sizeof(struct gfs2_quota_change);
282
283         /* Compute maximum reservation required to add a entry to a directory */
284
285         hash_blocks = DIV_ROUND_UP(sizeof(u64) * (1 << GFS2_DIR_MAX_DEPTH),
286                              sdp->sd_jbsize);
287
288         ind_blocks = 0;
289         for (tmp_blocks = hash_blocks; tmp_blocks > sdp->sd_diptrs;) {
290                 tmp_blocks = DIV_ROUND_UP(tmp_blocks, sdp->sd_inptrs);
291                 ind_blocks += tmp_blocks;
292         }
293
294         leaf_blocks = 2 + GFS2_DIR_MAX_DEPTH;
295
296         sdp->sd_max_dirres = hash_blocks + ind_blocks + leaf_blocks;
297
298         sdp->sd_heightsize[0] = sdp->sd_sb.sb_bsize -
299                                 sizeof(struct gfs2_dinode);
300         sdp->sd_heightsize[1] = sdp->sd_sb.sb_bsize * sdp->sd_diptrs;
301         for (x = 2;; x++) {
302                 u64 space, d;
303                 u32 m;
304
305                 space = sdp->sd_heightsize[x - 1] * sdp->sd_inptrs;
306                 d = space;
307                 m = do_div(d, sdp->sd_inptrs);
308
309                 if (d != sdp->sd_heightsize[x - 1] || m)
310                         break;
311                 sdp->sd_heightsize[x] = space;
312         }
313         sdp->sd_max_height = x;
314         gfs2_assert(sdp, sdp->sd_max_height <= GFS2_MAX_META_HEIGHT);
315
316         sdp->sd_jheightsize[0] = sdp->sd_sb.sb_bsize -
317                                  sizeof(struct gfs2_dinode);
318         sdp->sd_jheightsize[1] = sdp->sd_jbsize * sdp->sd_diptrs;
319         for (x = 2;; x++) {
320                 u64 space, d;
321                 u32 m;
322
323                 space = sdp->sd_jheightsize[x - 1] * sdp->sd_inptrs;
324                 d = space;
325                 m = do_div(d, sdp->sd_inptrs);
326
327                 if (d != sdp->sd_jheightsize[x - 1] || m)
328                         break;
329                 sdp->sd_jheightsize[x] = space;
330         }
331         sdp->sd_max_jheight = x;
332         gfs2_assert(sdp, sdp->sd_max_jheight <= GFS2_MAX_META_HEIGHT);
333
334         return 0;
335 }
336
337 /**
338  * gfs2_jindex_hold - Grab a lock on the jindex
339  * @sdp: The GFS2 superblock
340  * @ji_gh: the holder for the jindex glock
341  *
342  * This is very similar to the gfs2_rindex_hold() function, except that
343  * in general we hold the jindex lock for longer periods of time and
344  * we grab it far less frequently (in general) then the rgrp lock.
345  *
346  * Returns: errno
347  */
348
349 int gfs2_jindex_hold(struct gfs2_sbd *sdp, struct gfs2_holder *ji_gh)
350 {
351         struct gfs2_inode *dip = GFS2_I(sdp->sd_jindex);
352         struct qstr name;
353         char buf[20];
354         struct gfs2_jdesc *jd;
355         int error;
356
357         name.name = buf;
358
359         mutex_lock(&sdp->sd_jindex_mutex);
360
361         for (;;) {
362                 error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED,
363                                            GL_LOCAL_EXCL, ji_gh);
364                 if (error)
365                         break;
366
367                 name.len = sprintf(buf, "journal%u", sdp->sd_journals);
368                 name.hash = gfs2_disk_hash(name.name, name.len);
369
370                 error = gfs2_dir_search(sdp->sd_jindex, &name, NULL, NULL);
371                 if (error == -ENOENT) {
372                         error = 0;
373                         break;
374                 }
375
376                 gfs2_glock_dq_uninit(ji_gh);
377
378                 if (error)
379                         break;
380
381                 error = -ENOMEM;
382                 jd = kzalloc(sizeof(struct gfs2_jdesc), GFP_KERNEL);
383                 if (!jd)
384                         break;
385
386                 jd->jd_inode = gfs2_lookupi(sdp->sd_jindex, &name, 1, NULL);
387                 if (!jd->jd_inode || IS_ERR(jd->jd_inode)) {
388                         if (!jd->jd_inode)
389                                 error = -ENOENT;
390                         else
391                                 error = PTR_ERR(jd->jd_inode);
392                         kfree(jd);
393                         break;
394                 }
395
396                 spin_lock(&sdp->sd_jindex_spin);
397                 jd->jd_jid = sdp->sd_journals++;
398                 list_add_tail(&jd->jd_list, &sdp->sd_jindex_list);
399                 spin_unlock(&sdp->sd_jindex_spin);
400         }
401
402         mutex_unlock(&sdp->sd_jindex_mutex);
403
404         return error;
405 }
406
407 /**
408  * gfs2_jindex_free - Clear all the journal index information
409  * @sdp: The GFS2 superblock
410  *
411  */
412
413 void gfs2_jindex_free(struct gfs2_sbd *sdp)
414 {
415         struct list_head list;
416         struct gfs2_jdesc *jd;
417
418         spin_lock(&sdp->sd_jindex_spin);
419         list_add(&list, &sdp->sd_jindex_list);
420         list_del_init(&sdp->sd_jindex_list);
421         sdp->sd_journals = 0;
422         spin_unlock(&sdp->sd_jindex_spin);
423
424         while (!list_empty(&list)) {
425                 jd = list_entry(list.next, struct gfs2_jdesc, jd_list);
426                 list_del(&jd->jd_list);
427                 iput(jd->jd_inode);
428                 kfree(jd);
429         }
430 }
431
432 static struct gfs2_jdesc *jdesc_find_i(struct list_head *head, unsigned int jid)
433 {
434         struct gfs2_jdesc *jd;
435         int found = 0;
436
437         list_for_each_entry(jd, head, jd_list) {
438                 if (jd->jd_jid == jid) {
439                         found = 1;
440                         break;
441                 }
442         }
443
444         if (!found)
445                 jd = NULL;
446
447         return jd;
448 }
449
450 struct gfs2_jdesc *gfs2_jdesc_find(struct gfs2_sbd *sdp, unsigned int jid)
451 {
452         struct gfs2_jdesc *jd;
453
454         spin_lock(&sdp->sd_jindex_spin);
455         jd = jdesc_find_i(&sdp->sd_jindex_list, jid);
456         spin_unlock(&sdp->sd_jindex_spin);
457
458         return jd;
459 }
460
461 void gfs2_jdesc_make_dirty(struct gfs2_sbd *sdp, unsigned int jid)
462 {
463         struct gfs2_jdesc *jd;
464
465         spin_lock(&sdp->sd_jindex_spin);
466         jd = jdesc_find_i(&sdp->sd_jindex_list, jid);
467         if (jd)
468                 jd->jd_dirty = 1;
469         spin_unlock(&sdp->sd_jindex_spin);
470 }
471
472 struct gfs2_jdesc *gfs2_jdesc_find_dirty(struct gfs2_sbd *sdp)
473 {
474         struct gfs2_jdesc *jd;
475         int found = 0;
476
477         spin_lock(&sdp->sd_jindex_spin);
478
479         list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
480                 if (jd->jd_dirty) {
481                         jd->jd_dirty = 0;
482                         found = 1;
483                         break;
484                 }
485         }
486         spin_unlock(&sdp->sd_jindex_spin);
487
488         if (!found)
489                 jd = NULL;
490
491         return jd;
492 }
493
494 int gfs2_jdesc_check(struct gfs2_jdesc *jd)
495 {
496         struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
497         struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
498         int ar;
499         int error;
500
501         if (ip->i_di.di_size < (8 << 20) || ip->i_di.di_size > (1 << 30) ||
502             (ip->i_di.di_size & (sdp->sd_sb.sb_bsize - 1))) {
503                 gfs2_consist_inode(ip);
504                 return -EIO;
505         }
506         jd->jd_blocks = ip->i_di.di_size >> sdp->sd_sb.sb_bsize_shift;
507
508         error = gfs2_write_alloc_required(ip, 0, ip->i_di.di_size, &ar);
509         if (!error && ar) {
510                 gfs2_consist_inode(ip);
511                 error = -EIO;
512         }
513
514         return error;
515 }
516
517 /**
518  * gfs2_make_fs_rw - Turn a Read-Only FS into a Read-Write one
519  * @sdp: the filesystem
520  *
521  * Returns: errno
522  */
523
524 int gfs2_make_fs_rw(struct gfs2_sbd *sdp)
525 {
526         struct gfs2_inode *ip = GFS2_I(sdp->sd_jdesc->jd_inode);
527         struct gfs2_glock *j_gl = ip->i_gl;
528         struct gfs2_holder t_gh;
529         struct gfs2_log_header_host head;
530         int error;
531
532         error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED,
533                                    GL_LOCAL_EXCL, &t_gh);
534         if (error)
535                 return error;
536
537         gfs2_meta_cache_flush(ip);
538         j_gl->gl_ops->go_inval(j_gl, DIO_METADATA);
539
540         error = gfs2_find_jhead(sdp->sd_jdesc, &head);
541         if (error)
542                 goto fail;
543
544         if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
545                 gfs2_consist(sdp);
546                 error = -EIO;
547                 goto fail;
548         }
549
550         /*  Initialize some head of the log stuff  */
551         sdp->sd_log_sequence = head.lh_sequence + 1;
552         gfs2_log_pointers_init(sdp, head.lh_blkno);
553
554         error = gfs2_quota_init(sdp);
555         if (error)
556                 goto fail;
557
558         set_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
559
560         gfs2_glock_dq_uninit(&t_gh);
561
562         return 0;
563
564 fail:
565         t_gh.gh_flags |= GL_NOCACHE;
566         gfs2_glock_dq_uninit(&t_gh);
567
568         return error;
569 }
570
571 /**
572  * gfs2_make_fs_ro - Turn a Read-Write FS into a Read-Only one
573  * @sdp: the filesystem
574  *
575  * Returns: errno
576  */
577
578 int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
579 {
580         struct gfs2_holder t_gh;
581         int error;
582
583         gfs2_quota_sync(sdp);
584         gfs2_statfs_sync(sdp);
585
586         error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED,
587                                 GL_LOCAL_EXCL | GL_NOCACHE,
588                                 &t_gh);
589         if (error && !test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
590                 return error;
591
592         gfs2_meta_syncfs(sdp);
593         gfs2_log_shutdown(sdp);
594
595         clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
596
597         if (t_gh.gh_gl)
598                 gfs2_glock_dq_uninit(&t_gh);
599
600         gfs2_quota_cleanup(sdp);
601
602         return error;
603 }
604
605 int gfs2_statfs_init(struct gfs2_sbd *sdp)
606 {
607         struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
608         struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
609         struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
610         struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
611         struct buffer_head *m_bh, *l_bh;
612         struct gfs2_holder gh;
613         int error;
614
615         error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, GL_NOCACHE,
616                                    &gh);
617         if (error)
618                 return error;
619
620         error = gfs2_meta_inode_buffer(m_ip, &m_bh);
621         if (error)
622                 goto out;
623
624         if (sdp->sd_args.ar_spectator) {
625                 spin_lock(&sdp->sd_statfs_spin);
626                 gfs2_statfs_change_in(m_sc, m_bh->b_data +
627                                       sizeof(struct gfs2_dinode));
628                 spin_unlock(&sdp->sd_statfs_spin);
629         } else {
630                 error = gfs2_meta_inode_buffer(l_ip, &l_bh);
631                 if (error)
632                         goto out_m_bh;
633
634                 spin_lock(&sdp->sd_statfs_spin);
635                 gfs2_statfs_change_in(m_sc, m_bh->b_data +
636                                       sizeof(struct gfs2_dinode));
637                 gfs2_statfs_change_in(l_sc, l_bh->b_data +
638                                       sizeof(struct gfs2_dinode));
639                 spin_unlock(&sdp->sd_statfs_spin);
640
641                 brelse(l_bh);
642         }
643
644 out_m_bh:
645         brelse(m_bh);
646 out:
647         gfs2_glock_dq_uninit(&gh);
648         return 0;
649 }
650
651 void gfs2_statfs_change(struct gfs2_sbd *sdp, s64 total, s64 free,
652                         s64 dinodes)
653 {
654         struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
655         struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
656         struct buffer_head *l_bh;
657         int error;
658
659         error = gfs2_meta_inode_buffer(l_ip, &l_bh);
660         if (error)
661                 return;
662
663         mutex_lock(&sdp->sd_statfs_mutex);
664         gfs2_trans_add_bh(l_ip->i_gl, l_bh, 1);
665         mutex_unlock(&sdp->sd_statfs_mutex);
666
667         spin_lock(&sdp->sd_statfs_spin);
668         l_sc->sc_total += total;
669         l_sc->sc_free += free;
670         l_sc->sc_dinodes += dinodes;
671         gfs2_statfs_change_out(l_sc, l_bh->b_data + sizeof(struct gfs2_dinode));
672         spin_unlock(&sdp->sd_statfs_spin);
673
674         brelse(l_bh);
675 }
676
677 int gfs2_statfs_sync(struct gfs2_sbd *sdp)
678 {
679         struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
680         struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
681         struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
682         struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
683         struct gfs2_holder gh;
684         struct buffer_head *m_bh, *l_bh;
685         int error;
686
687         error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, GL_NOCACHE,
688                                    &gh);
689         if (error)
690                 return error;
691
692         error = gfs2_meta_inode_buffer(m_ip, &m_bh);
693         if (error)
694                 goto out;
695
696         spin_lock(&sdp->sd_statfs_spin);
697         gfs2_statfs_change_in(m_sc, m_bh->b_data +
698                               sizeof(struct gfs2_dinode));
699         if (!l_sc->sc_total && !l_sc->sc_free && !l_sc->sc_dinodes) {
700                 spin_unlock(&sdp->sd_statfs_spin);
701                 goto out_bh;
702         }
703         spin_unlock(&sdp->sd_statfs_spin);
704
705         error = gfs2_meta_inode_buffer(l_ip, &l_bh);
706         if (error)
707                 goto out_bh;
708
709         error = gfs2_trans_begin(sdp, 2 * RES_DINODE, 0);
710         if (error)
711                 goto out_bh2;
712
713         mutex_lock(&sdp->sd_statfs_mutex);
714         gfs2_trans_add_bh(l_ip->i_gl, l_bh, 1);
715         mutex_unlock(&sdp->sd_statfs_mutex);
716
717         spin_lock(&sdp->sd_statfs_spin);
718         m_sc->sc_total += l_sc->sc_total;
719         m_sc->sc_free += l_sc->sc_free;
720         m_sc->sc_dinodes += l_sc->sc_dinodes;
721         memset(l_sc, 0, sizeof(struct gfs2_statfs_change));
722         memset(l_bh->b_data + sizeof(struct gfs2_dinode),
723                0, sizeof(struct gfs2_statfs_change));
724         spin_unlock(&sdp->sd_statfs_spin);
725
726         gfs2_trans_add_bh(m_ip->i_gl, m_bh, 1);
727         gfs2_statfs_change_out(m_sc, m_bh->b_data + sizeof(struct gfs2_dinode));
728
729         gfs2_trans_end(sdp);
730
731 out_bh2:
732         brelse(l_bh);
733 out_bh:
734         brelse(m_bh);
735 out:
736         gfs2_glock_dq_uninit(&gh);
737         return error;
738 }
739
740 /**
741  * gfs2_statfs_i - Do a statfs
742  * @sdp: the filesystem
743  * @sg: the sg structure
744  *
745  * Returns: errno
746  */
747
748 int gfs2_statfs_i(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
749 {
750         struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
751         struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
752
753         spin_lock(&sdp->sd_statfs_spin);
754
755         *sc = *m_sc;
756         sc->sc_total += l_sc->sc_total;
757         sc->sc_free += l_sc->sc_free;
758         sc->sc_dinodes += l_sc->sc_dinodes;
759
760         spin_unlock(&sdp->sd_statfs_spin);
761
762         if (sc->sc_free < 0)
763                 sc->sc_free = 0;
764         if (sc->sc_free > sc->sc_total)
765                 sc->sc_free = sc->sc_total;
766         if (sc->sc_dinodes < 0)
767                 sc->sc_dinodes = 0;
768
769         return 0;
770 }
771
772 /**
773  * statfs_fill - fill in the sg for a given RG
774  * @rgd: the RG
775  * @sc: the sc structure
776  *
777  * Returns: 0 on success, -ESTALE if the LVB is invalid
778  */
779
780 static int statfs_slow_fill(struct gfs2_rgrpd *rgd,
781                             struct gfs2_statfs_change_host *sc)
782 {
783         gfs2_rgrp_verify(rgd);
784         sc->sc_total += rgd->rd_ri.ri_data;
785         sc->sc_free += rgd->rd_rg.rg_free;
786         sc->sc_dinodes += rgd->rd_rg.rg_dinodes;
787         return 0;
788 }
789
790 /**
791  * gfs2_statfs_slow - Stat a filesystem using asynchronous locking
792  * @sdp: the filesystem
793  * @sc: the sc info that will be returned
794  *
795  * Any error (other than a signal) will cause this routine to fall back
796  * to the synchronous version.
797  *
798  * FIXME: This really shouldn't busy wait like this.
799  *
800  * Returns: errno
801  */
802
803 int gfs2_statfs_slow(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
804 {
805         struct gfs2_holder ri_gh;
806         struct gfs2_rgrpd *rgd_next;
807         struct gfs2_holder *gha, *gh;
808         unsigned int slots = 64;
809         unsigned int x;
810         int done;
811         int error = 0, err;
812
813         memset(sc, 0, sizeof(struct gfs2_statfs_change_host));
814         gha = kcalloc(slots, sizeof(struct gfs2_holder), GFP_KERNEL);
815         if (!gha)
816                 return -ENOMEM;
817
818         error = gfs2_rindex_hold(sdp, &ri_gh);
819         if (error)
820                 goto out;
821
822         rgd_next = gfs2_rgrpd_get_first(sdp);
823
824         for (;;) {
825                 done = 1;
826
827                 for (x = 0; x < slots; x++) {
828                         gh = gha + x;
829
830                         if (gh->gh_gl && gfs2_glock_poll(gh)) {
831                                 err = gfs2_glock_wait(gh);
832                                 if (err) {
833                                         gfs2_holder_uninit(gh);
834                                         error = err;
835                                 } else {
836                                         if (!error)
837                                                 error = statfs_slow_fill(
838                                                         gh->gh_gl->gl_object, sc);
839                                         gfs2_glock_dq_uninit(gh);
840                                 }
841                         }
842
843                         if (gh->gh_gl)
844                                 done = 0;
845                         else if (rgd_next && !error) {
846                                 error = gfs2_glock_nq_init(rgd_next->rd_gl,
847                                                            LM_ST_SHARED,
848                                                            GL_ASYNC,
849                                                            gh);
850                                 rgd_next = gfs2_rgrpd_get_next(rgd_next);
851                                 done = 0;
852                         }
853
854                         if (signal_pending(current))
855                                 error = -ERESTARTSYS;
856                 }
857
858                 if (done)
859                         break;
860
861                 yield();
862         }
863
864         gfs2_glock_dq_uninit(&ri_gh);
865
866 out:
867         kfree(gha);
868         return error;
869 }
870
871 struct lfcc {
872         struct list_head list;
873         struct gfs2_holder gh;
874 };
875
876 /**
877  * gfs2_lock_fs_check_clean - Stop all writes to the FS and check that all
878  *                            journals are clean
879  * @sdp: the file system
880  * @state: the state to put the transaction lock into
881  * @t_gh: the hold on the transaction lock
882  *
883  * Returns: errno
884  */
885
886 static int gfs2_lock_fs_check_clean(struct gfs2_sbd *sdp,
887                                     struct gfs2_holder *t_gh)
888 {
889         struct gfs2_inode *ip;
890         struct gfs2_holder ji_gh;
891         struct gfs2_jdesc *jd;
892         struct lfcc *lfcc;
893         LIST_HEAD(list);
894         struct gfs2_log_header_host lh;
895         int error;
896
897         error = gfs2_jindex_hold(sdp, &ji_gh);
898         if (error)
899                 return error;
900
901         list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
902                 lfcc = kmalloc(sizeof(struct lfcc), GFP_KERNEL);
903                 if (!lfcc) {
904                         error = -ENOMEM;
905                         goto out;
906                 }
907                 ip = GFS2_I(jd->jd_inode);
908                 error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &lfcc->gh);
909                 if (error) {
910                         kfree(lfcc);
911                         goto out;
912                 }
913                 list_add(&lfcc->list, &list);
914         }
915
916         error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_DEFERRED,
917                                LM_FLAG_PRIORITY | GL_NOCACHE,
918                                t_gh);
919
920         list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
921                 error = gfs2_jdesc_check(jd);
922                 if (error)
923                         break;
924                 error = gfs2_find_jhead(jd, &lh);
925                 if (error)
926                         break;
927                 if (!(lh.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
928                         error = -EBUSY;
929                         break;
930                 }
931         }
932
933         if (error)
934                 gfs2_glock_dq_uninit(t_gh);
935
936 out:
937         while (!list_empty(&list)) {
938                 lfcc = list_entry(list.next, struct lfcc, list);
939                 list_del(&lfcc->list);
940                 gfs2_glock_dq_uninit(&lfcc->gh);
941                 kfree(lfcc);
942         }
943         gfs2_glock_dq_uninit(&ji_gh);
944         return error;
945 }
946
947 /**
948  * gfs2_freeze_fs - freezes the file system
949  * @sdp: the file system
950  *
951  * This function flushes data and meta data for all machines by
952  * aquiring the transaction log exclusively.  All journals are
953  * ensured to be in a clean state as well.
954  *
955  * Returns: errno
956  */
957
958 int gfs2_freeze_fs(struct gfs2_sbd *sdp)
959 {
960         int error = 0;
961
962         mutex_lock(&sdp->sd_freeze_lock);
963
964         if (!sdp->sd_freeze_count++) {
965                 error = gfs2_lock_fs_check_clean(sdp, &sdp->sd_freeze_gh);
966                 if (error)
967                         sdp->sd_freeze_count--;
968         }
969
970         mutex_unlock(&sdp->sd_freeze_lock);
971
972         return error;
973 }
974
975 /**
976  * gfs2_unfreeze_fs - unfreezes the file system
977  * @sdp: the file system
978  *
979  * This function allows the file system to proceed by unlocking
980  * the exclusively held transaction lock.  Other GFS2 nodes are
981  * now free to acquire the lock shared and go on with their lives.
982  *
983  */
984
985 void gfs2_unfreeze_fs(struct gfs2_sbd *sdp)
986 {
987         mutex_lock(&sdp->sd_freeze_lock);
988
989         if (sdp->sd_freeze_count && !--sdp->sd_freeze_count)
990                 gfs2_glock_dq_uninit(&sdp->sd_freeze_gh);
991
992         mutex_unlock(&sdp->sd_freeze_lock);
993 }
994