xref: /linux/fs/gfs2/super.c (revision 2d7f3d1a5866705be2393150e1ffdf67030ab88d)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
4  * Copyright (C) 2004-2007 Red Hat, Inc.  All rights reserved.
5  */
6 
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8 
9 #include <linux/bio.h>
10 #include <linux/sched/signal.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/statfs.h>
16 #include <linux/seq_file.h>
17 #include <linux/mount.h>
18 #include <linux/kthread.h>
19 #include <linux/delay.h>
20 #include <linux/gfs2_ondisk.h>
21 #include <linux/crc32.h>
22 #include <linux/time.h>
23 #include <linux/wait.h>
24 #include <linux/writeback.h>
25 #include <linux/backing-dev.h>
26 #include <linux/kernel.h>
27 
28 #include "gfs2.h"
29 #include "incore.h"
30 #include "bmap.h"
31 #include "dir.h"
32 #include "glock.h"
33 #include "glops.h"
34 #include "inode.h"
35 #include "log.h"
36 #include "meta_io.h"
37 #include "quota.h"
38 #include "recovery.h"
39 #include "rgrp.h"
40 #include "super.h"
41 #include "trans.h"
42 #include "util.h"
43 #include "sys.h"
44 #include "xattr.h"
45 #include "lops.h"
46 
47 enum dinode_demise {
48 	SHOULD_DELETE_DINODE,
49 	SHOULD_NOT_DELETE_DINODE,
50 	SHOULD_DEFER_EVICTION,
51 };
52 
53 /**
54  * gfs2_jindex_free - Clear all the journal index information
55  * @sdp: The GFS2 superblock
56  *
57  */
58 
59 void gfs2_jindex_free(struct gfs2_sbd *sdp)
60 {
61 	struct list_head list;
62 	struct gfs2_jdesc *jd;
63 
64 	spin_lock(&sdp->sd_jindex_spin);
65 	list_add(&list, &sdp->sd_jindex_list);
66 	list_del_init(&sdp->sd_jindex_list);
67 	sdp->sd_journals = 0;
68 	spin_unlock(&sdp->sd_jindex_spin);
69 
70 	sdp->sd_jdesc = NULL;
71 	while (!list_empty(&list)) {
72 		jd = list_first_entry(&list, struct gfs2_jdesc, jd_list);
73 		gfs2_free_journal_extents(jd);
74 		list_del(&jd->jd_list);
75 		iput(jd->jd_inode);
76 		jd->jd_inode = NULL;
77 		kfree(jd);
78 	}
79 }
80 
81 static struct gfs2_jdesc *jdesc_find_i(struct list_head *head, unsigned int jid)
82 {
83 	struct gfs2_jdesc *jd;
84 
85 	list_for_each_entry(jd, head, jd_list) {
86 		if (jd->jd_jid == jid)
87 			return jd;
88 	}
89 	return NULL;
90 }
91 
92 struct gfs2_jdesc *gfs2_jdesc_find(struct gfs2_sbd *sdp, unsigned int jid)
93 {
94 	struct gfs2_jdesc *jd;
95 
96 	spin_lock(&sdp->sd_jindex_spin);
97 	jd = jdesc_find_i(&sdp->sd_jindex_list, jid);
98 	spin_unlock(&sdp->sd_jindex_spin);
99 
100 	return jd;
101 }
102 
103 int gfs2_jdesc_check(struct gfs2_jdesc *jd)
104 {
105 	struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
106 	struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
107 	u64 size = i_size_read(jd->jd_inode);
108 
109 	if (gfs2_check_internal_file_size(jd->jd_inode, 8 << 20, BIT(30)))
110 		return -EIO;
111 
112 	jd->jd_blocks = size >> sdp->sd_sb.sb_bsize_shift;
113 
114 	if (gfs2_write_alloc_required(ip, 0, size)) {
115 		gfs2_consist_inode(ip);
116 		return -EIO;
117 	}
118 
119 	return 0;
120 }
121 
122 /**
123  * gfs2_make_fs_rw - Turn a Read-Only FS into a Read-Write one
124  * @sdp: the filesystem
125  *
126  * Returns: errno
127  */
128 
129 int gfs2_make_fs_rw(struct gfs2_sbd *sdp)
130 {
131 	struct gfs2_inode *ip = GFS2_I(sdp->sd_jdesc->jd_inode);
132 	struct gfs2_glock *j_gl = ip->i_gl;
133 	struct gfs2_log_header_host head;
134 	int error;
135 
136 	j_gl->gl_ops->go_inval(j_gl, DIO_METADATA);
137 	if (gfs2_withdrawing_or_withdrawn(sdp))
138 		return -EIO;
139 
140 	error = gfs2_find_jhead(sdp->sd_jdesc, &head, false);
141 	if (error) {
142 		gfs2_consist(sdp);
143 		return error;
144 	}
145 
146 	if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
147 		gfs2_consist(sdp);
148 		return -EIO;
149 	}
150 
151 	/*  Initialize some head of the log stuff  */
152 	sdp->sd_log_sequence = head.lh_sequence + 1;
153 	gfs2_log_pointers_init(sdp, head.lh_blkno);
154 
155 	error = gfs2_quota_init(sdp);
156 	if (!error && gfs2_withdrawing_or_withdrawn(sdp))
157 		error = -EIO;
158 	if (!error)
159 		set_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
160 	return error;
161 }
162 
163 void gfs2_statfs_change_in(struct gfs2_statfs_change_host *sc, const void *buf)
164 {
165 	const struct gfs2_statfs_change *str = buf;
166 
167 	sc->sc_total = be64_to_cpu(str->sc_total);
168 	sc->sc_free = be64_to_cpu(str->sc_free);
169 	sc->sc_dinodes = be64_to_cpu(str->sc_dinodes);
170 }
171 
172 void gfs2_statfs_change_out(const struct gfs2_statfs_change_host *sc, void *buf)
173 {
174 	struct gfs2_statfs_change *str = buf;
175 
176 	str->sc_total = cpu_to_be64(sc->sc_total);
177 	str->sc_free = cpu_to_be64(sc->sc_free);
178 	str->sc_dinodes = cpu_to_be64(sc->sc_dinodes);
179 }
180 
181 int gfs2_statfs_init(struct gfs2_sbd *sdp)
182 {
183 	struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
184 	struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
185 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
186 	struct buffer_head *m_bh;
187 	struct gfs2_holder gh;
188 	int error;
189 
190 	error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, GL_NOCACHE,
191 				   &gh);
192 	if (error)
193 		return error;
194 
195 	error = gfs2_meta_inode_buffer(m_ip, &m_bh);
196 	if (error)
197 		goto out;
198 
199 	if (sdp->sd_args.ar_spectator) {
200 		spin_lock(&sdp->sd_statfs_spin);
201 		gfs2_statfs_change_in(m_sc, m_bh->b_data +
202 				      sizeof(struct gfs2_dinode));
203 		spin_unlock(&sdp->sd_statfs_spin);
204 	} else {
205 		spin_lock(&sdp->sd_statfs_spin);
206 		gfs2_statfs_change_in(m_sc, m_bh->b_data +
207 				      sizeof(struct gfs2_dinode));
208 		gfs2_statfs_change_in(l_sc, sdp->sd_sc_bh->b_data +
209 				      sizeof(struct gfs2_dinode));
210 		spin_unlock(&sdp->sd_statfs_spin);
211 
212 	}
213 
214 	brelse(m_bh);
215 out:
216 	gfs2_glock_dq_uninit(&gh);
217 	return 0;
218 }
219 
220 void gfs2_statfs_change(struct gfs2_sbd *sdp, s64 total, s64 free,
221 			s64 dinodes)
222 {
223 	struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
224 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
225 	struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
226 	s64 x, y;
227 	int need_sync = 0;
228 
229 	gfs2_trans_add_meta(l_ip->i_gl, sdp->sd_sc_bh);
230 
231 	spin_lock(&sdp->sd_statfs_spin);
232 	l_sc->sc_total += total;
233 	l_sc->sc_free += free;
234 	l_sc->sc_dinodes += dinodes;
235 	gfs2_statfs_change_out(l_sc, sdp->sd_sc_bh->b_data +
236 			       sizeof(struct gfs2_dinode));
237 	if (sdp->sd_args.ar_statfs_percent) {
238 		x = 100 * l_sc->sc_free;
239 		y = m_sc->sc_free * sdp->sd_args.ar_statfs_percent;
240 		if (x >= y || x <= -y)
241 			need_sync = 1;
242 	}
243 	spin_unlock(&sdp->sd_statfs_spin);
244 
245 	if (need_sync)
246 		gfs2_wake_up_statfs(sdp);
247 }
248 
249 void update_statfs(struct gfs2_sbd *sdp, struct buffer_head *m_bh)
250 {
251 	struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
252 	struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
253 	struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
254 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
255 
256 	gfs2_trans_add_meta(l_ip->i_gl, sdp->sd_sc_bh);
257 	gfs2_trans_add_meta(m_ip->i_gl, m_bh);
258 
259 	spin_lock(&sdp->sd_statfs_spin);
260 	m_sc->sc_total += l_sc->sc_total;
261 	m_sc->sc_free += l_sc->sc_free;
262 	m_sc->sc_dinodes += l_sc->sc_dinodes;
263 	memset(l_sc, 0, sizeof(struct gfs2_statfs_change));
264 	memset(sdp->sd_sc_bh->b_data + sizeof(struct gfs2_dinode),
265 	       0, sizeof(struct gfs2_statfs_change));
266 	gfs2_statfs_change_out(m_sc, m_bh->b_data + sizeof(struct gfs2_dinode));
267 	spin_unlock(&sdp->sd_statfs_spin);
268 }
269 
270 int gfs2_statfs_sync(struct super_block *sb, int type)
271 {
272 	struct gfs2_sbd *sdp = sb->s_fs_info;
273 	struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
274 	struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
275 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
276 	struct gfs2_holder gh;
277 	struct buffer_head *m_bh;
278 	int error;
279 
280 	error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, GL_NOCACHE,
281 				   &gh);
282 	if (error)
283 		goto out;
284 
285 	error = gfs2_meta_inode_buffer(m_ip, &m_bh);
286 	if (error)
287 		goto out_unlock;
288 
289 	spin_lock(&sdp->sd_statfs_spin);
290 	gfs2_statfs_change_in(m_sc, m_bh->b_data +
291 			      sizeof(struct gfs2_dinode));
292 	if (!l_sc->sc_total && !l_sc->sc_free && !l_sc->sc_dinodes) {
293 		spin_unlock(&sdp->sd_statfs_spin);
294 		goto out_bh;
295 	}
296 	spin_unlock(&sdp->sd_statfs_spin);
297 
298 	error = gfs2_trans_begin(sdp, 2 * RES_DINODE, 0);
299 	if (error)
300 		goto out_bh;
301 
302 	update_statfs(sdp, m_bh);
303 	sdp->sd_statfs_force_sync = 0;
304 
305 	gfs2_trans_end(sdp);
306 
307 out_bh:
308 	brelse(m_bh);
309 out_unlock:
310 	gfs2_glock_dq_uninit(&gh);
311 out:
312 	return error;
313 }
314 
315 struct lfcc {
316 	struct list_head list;
317 	struct gfs2_holder gh;
318 };
319 
320 /**
321  * gfs2_lock_fs_check_clean - Stop all writes to the FS and check that all
322  *                            journals are clean
323  * @sdp: the file system
324  *
325  * Returns: errno
326  */
327 
328 static int gfs2_lock_fs_check_clean(struct gfs2_sbd *sdp)
329 {
330 	struct gfs2_inode *ip;
331 	struct gfs2_jdesc *jd;
332 	struct lfcc *lfcc;
333 	LIST_HEAD(list);
334 	struct gfs2_log_header_host lh;
335 	int error, error2;
336 
337 	/*
338 	 * Grab all the journal glocks in SH mode.  We are *probably* doing
339 	 * that to prevent recovery.
340 	 */
341 
342 	list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
343 		lfcc = kmalloc(sizeof(struct lfcc), GFP_KERNEL);
344 		if (!lfcc) {
345 			error = -ENOMEM;
346 			goto out;
347 		}
348 		ip = GFS2_I(jd->jd_inode);
349 		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &lfcc->gh);
350 		if (error) {
351 			kfree(lfcc);
352 			goto out;
353 		}
354 		list_add(&lfcc->list, &list);
355 	}
356 
357 	gfs2_freeze_unlock(&sdp->sd_freeze_gh);
358 
359 	error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_EXCLUSIVE,
360 				   LM_FLAG_NOEXP | GL_NOPID,
361 				   &sdp->sd_freeze_gh);
362 	if (error)
363 		goto relock_shared;
364 
365 	list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
366 		error = gfs2_jdesc_check(jd);
367 		if (error)
368 			break;
369 		error = gfs2_find_jhead(jd, &lh, false);
370 		if (error)
371 			break;
372 		if (!(lh.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
373 			error = -EBUSY;
374 			break;
375 		}
376 	}
377 
378 	if (!error)
379 		goto out;  /* success */
380 
381 	gfs2_freeze_unlock(&sdp->sd_freeze_gh);
382 
383 relock_shared:
384 	error2 = gfs2_freeze_lock_shared(sdp);
385 	gfs2_assert_withdraw(sdp, !error2);
386 
387 out:
388 	while (!list_empty(&list)) {
389 		lfcc = list_first_entry(&list, struct lfcc, list);
390 		list_del(&lfcc->list);
391 		gfs2_glock_dq_uninit(&lfcc->gh);
392 		kfree(lfcc);
393 	}
394 	return error;
395 }
396 
397 void gfs2_dinode_out(const struct gfs2_inode *ip, void *buf)
398 {
399 	const struct inode *inode = &ip->i_inode;
400 	struct gfs2_dinode *str = buf;
401 
402 	str->di_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
403 	str->di_header.mh_type = cpu_to_be32(GFS2_METATYPE_DI);
404 	str->di_header.mh_format = cpu_to_be32(GFS2_FORMAT_DI);
405 	str->di_num.no_addr = cpu_to_be64(ip->i_no_addr);
406 	str->di_num.no_formal_ino = cpu_to_be64(ip->i_no_formal_ino);
407 	str->di_mode = cpu_to_be32(inode->i_mode);
408 	str->di_uid = cpu_to_be32(i_uid_read(inode));
409 	str->di_gid = cpu_to_be32(i_gid_read(inode));
410 	str->di_nlink = cpu_to_be32(inode->i_nlink);
411 	str->di_size = cpu_to_be64(i_size_read(inode));
412 	str->di_blocks = cpu_to_be64(gfs2_get_inode_blocks(inode));
413 	str->di_atime = cpu_to_be64(inode_get_atime_sec(inode));
414 	str->di_mtime = cpu_to_be64(inode_get_mtime_sec(inode));
415 	str->di_ctime = cpu_to_be64(inode_get_ctime_sec(inode));
416 
417 	str->di_goal_meta = cpu_to_be64(ip->i_goal);
418 	str->di_goal_data = cpu_to_be64(ip->i_goal);
419 	str->di_generation = cpu_to_be64(ip->i_generation);
420 
421 	str->di_flags = cpu_to_be32(ip->i_diskflags);
422 	str->di_height = cpu_to_be16(ip->i_height);
423 	str->di_payload_format = cpu_to_be32(S_ISDIR(inode->i_mode) &&
424 					     !(ip->i_diskflags & GFS2_DIF_EXHASH) ?
425 					     GFS2_FORMAT_DE : 0);
426 	str->di_depth = cpu_to_be16(ip->i_depth);
427 	str->di_entries = cpu_to_be32(ip->i_entries);
428 
429 	str->di_eattr = cpu_to_be64(ip->i_eattr);
430 	str->di_atime_nsec = cpu_to_be32(inode_get_atime_nsec(inode));
431 	str->di_mtime_nsec = cpu_to_be32(inode_get_mtime_nsec(inode));
432 	str->di_ctime_nsec = cpu_to_be32(inode_get_ctime_nsec(inode));
433 }
434 
435 /**
436  * gfs2_write_inode - Make sure the inode is stable on the disk
437  * @inode: The inode
438  * @wbc: The writeback control structure
439  *
440  * Returns: errno
441  */
442 
443 static int gfs2_write_inode(struct inode *inode, struct writeback_control *wbc)
444 {
445 	struct gfs2_inode *ip = GFS2_I(inode);
446 	struct gfs2_sbd *sdp = GFS2_SB(inode);
447 	struct address_space *metamapping = gfs2_glock2aspace(ip->i_gl);
448 	struct backing_dev_info *bdi = inode_to_bdi(metamapping->host);
449 	int ret = 0;
450 	bool flush_all = (wbc->sync_mode == WB_SYNC_ALL || gfs2_is_jdata(ip));
451 
452 	if (flush_all)
453 		gfs2_log_flush(GFS2_SB(inode), ip->i_gl,
454 			       GFS2_LOG_HEAD_FLUSH_NORMAL |
455 			       GFS2_LFC_WRITE_INODE);
456 	if (bdi->wb.dirty_exceeded)
457 		gfs2_ail1_flush(sdp, wbc);
458 	else
459 		filemap_fdatawrite(metamapping);
460 	if (flush_all)
461 		ret = filemap_fdatawait(metamapping);
462 	if (ret)
463 		mark_inode_dirty_sync(inode);
464 	else {
465 		spin_lock(&inode->i_lock);
466 		if (!(inode->i_flags & I_DIRTY))
467 			gfs2_ordered_del_inode(ip);
468 		spin_unlock(&inode->i_lock);
469 	}
470 	return ret;
471 }
472 
473 /**
474  * gfs2_dirty_inode - check for atime updates
475  * @inode: The inode in question
476  * @flags: The type of dirty
477  *
478  * Unfortunately it can be called under any combination of inode
479  * glock and freeze glock, so we have to check carefully.
480  *
481  * At the moment this deals only with atime - it should be possible
482  * to expand that role in future, once a review of the locking has
483  * been carried out.
484  */
485 
486 static void gfs2_dirty_inode(struct inode *inode, int flags)
487 {
488 	struct gfs2_inode *ip = GFS2_I(inode);
489 	struct gfs2_sbd *sdp = GFS2_SB(inode);
490 	struct buffer_head *bh;
491 	struct gfs2_holder gh;
492 	int need_unlock = 0;
493 	int need_endtrans = 0;
494 	int ret;
495 
496 	if (unlikely(!ip->i_gl)) {
497 		/* This can only happen during incomplete inode creation. */
498 		BUG_ON(!test_bit(GIF_ALLOC_FAILED, &ip->i_flags));
499 		return;
500 	}
501 
502 	if (gfs2_withdrawing_or_withdrawn(sdp))
503 		return;
504 	if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
505 		ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
506 		if (ret) {
507 			fs_err(sdp, "dirty_inode: glock %d\n", ret);
508 			gfs2_dump_glock(NULL, ip->i_gl, true);
509 			return;
510 		}
511 		need_unlock = 1;
512 	} else if (WARN_ON_ONCE(ip->i_gl->gl_state != LM_ST_EXCLUSIVE))
513 		return;
514 
515 	if (current->journal_info == NULL) {
516 		ret = gfs2_trans_begin(sdp, RES_DINODE, 0);
517 		if (ret) {
518 			fs_err(sdp, "dirty_inode: gfs2_trans_begin %d\n", ret);
519 			goto out;
520 		}
521 		need_endtrans = 1;
522 	}
523 
524 	ret = gfs2_meta_inode_buffer(ip, &bh);
525 	if (ret == 0) {
526 		gfs2_trans_add_meta(ip->i_gl, bh);
527 		gfs2_dinode_out(ip, bh->b_data);
528 		brelse(bh);
529 	}
530 
531 	if (need_endtrans)
532 		gfs2_trans_end(sdp);
533 out:
534 	if (need_unlock)
535 		gfs2_glock_dq_uninit(&gh);
536 }
537 
538 /**
539  * gfs2_make_fs_ro - Turn a Read-Write FS into a Read-Only one
540  * @sdp: the filesystem
541  *
542  * Returns: errno
543  */
544 
545 void gfs2_make_fs_ro(struct gfs2_sbd *sdp)
546 {
547 	int log_write_allowed = test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
548 
549 	if (!test_bit(SDF_KILL, &sdp->sd_flags))
550 		gfs2_flush_delete_work(sdp);
551 
552 	gfs2_destroy_threads(sdp);
553 
554 	if (log_write_allowed) {
555 		gfs2_quota_sync(sdp->sd_vfs, 0);
556 		gfs2_statfs_sync(sdp->sd_vfs, 0);
557 
558 		/* We do two log flushes here. The first one commits dirty inodes
559 		 * and rgrps to the journal, but queues up revokes to the ail list.
560 		 * The second flush writes out and removes the revokes.
561 		 *
562 		 * The first must be done before the FLUSH_SHUTDOWN code
563 		 * clears the LIVE flag, otherwise it will not be able to start
564 		 * a transaction to write its revokes, and the error will cause
565 		 * a withdraw of the file system. */
566 		gfs2_log_flush(sdp, NULL, GFS2_LFC_MAKE_FS_RO);
567 		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_SHUTDOWN |
568 			       GFS2_LFC_MAKE_FS_RO);
569 		wait_event_timeout(sdp->sd_log_waitq,
570 				   gfs2_log_is_empty(sdp),
571 				   HZ * 5);
572 		gfs2_assert_warn(sdp, gfs2_log_is_empty(sdp));
573 	}
574 	gfs2_quota_cleanup(sdp);
575 }
576 
577 /**
578  * gfs2_put_super - Unmount the filesystem
579  * @sb: The VFS superblock
580  *
581  */
582 
583 static void gfs2_put_super(struct super_block *sb)
584 {
585 	struct gfs2_sbd *sdp = sb->s_fs_info;
586 	struct gfs2_jdesc *jd;
587 
588 	/* No more recovery requests */
589 	set_bit(SDF_NORECOVERY, &sdp->sd_flags);
590 	smp_mb();
591 
592 	/* Wait on outstanding recovery */
593 restart:
594 	spin_lock(&sdp->sd_jindex_spin);
595 	list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
596 		if (!test_bit(JDF_RECOVERY, &jd->jd_flags))
597 			continue;
598 		spin_unlock(&sdp->sd_jindex_spin);
599 		wait_on_bit(&jd->jd_flags, JDF_RECOVERY,
600 			    TASK_UNINTERRUPTIBLE);
601 		goto restart;
602 	}
603 	spin_unlock(&sdp->sd_jindex_spin);
604 
605 	if (!sb_rdonly(sb))
606 		gfs2_make_fs_ro(sdp);
607 	else {
608 		if (gfs2_withdrawing_or_withdrawn(sdp))
609 			gfs2_destroy_threads(sdp);
610 
611 		gfs2_quota_cleanup(sdp);
612 	}
613 
614 	WARN_ON(gfs2_withdrawing(sdp));
615 
616 	/*  At this point, we're through modifying the disk  */
617 
618 	/*  Release stuff  */
619 
620 	gfs2_freeze_unlock(&sdp->sd_freeze_gh);
621 
622 	iput(sdp->sd_jindex);
623 	iput(sdp->sd_statfs_inode);
624 	iput(sdp->sd_rindex);
625 	iput(sdp->sd_quota_inode);
626 
627 	gfs2_glock_put(sdp->sd_rename_gl);
628 	gfs2_glock_put(sdp->sd_freeze_gl);
629 
630 	if (!sdp->sd_args.ar_spectator) {
631 		if (gfs2_holder_initialized(&sdp->sd_journal_gh))
632 			gfs2_glock_dq_uninit(&sdp->sd_journal_gh);
633 		if (gfs2_holder_initialized(&sdp->sd_jinode_gh))
634 			gfs2_glock_dq_uninit(&sdp->sd_jinode_gh);
635 		brelse(sdp->sd_sc_bh);
636 		gfs2_glock_dq_uninit(&sdp->sd_sc_gh);
637 		gfs2_glock_dq_uninit(&sdp->sd_qc_gh);
638 		free_local_statfs_inodes(sdp);
639 		iput(sdp->sd_qc_inode);
640 	}
641 
642 	gfs2_glock_dq_uninit(&sdp->sd_live_gh);
643 	gfs2_clear_rgrpd(sdp);
644 	gfs2_jindex_free(sdp);
645 	/*  Take apart glock structures and buffer lists  */
646 	gfs2_gl_hash_clear(sdp);
647 	truncate_inode_pages_final(&sdp->sd_aspace);
648 	gfs2_delete_debugfs_file(sdp);
649 	/*  Unmount the locking protocol  */
650 	gfs2_lm_unmount(sdp);
651 
652 	/*  At this point, we're through participating in the lockspace  */
653 	gfs2_sys_fs_del(sdp);
654 	free_sbd(sdp);
655 }
656 
657 /**
658  * gfs2_sync_fs - sync the filesystem
659  * @sb: the superblock
660  * @wait: true to wait for completion
661  *
662  * Flushes the log to disk.
663  */
664 
665 static int gfs2_sync_fs(struct super_block *sb, int wait)
666 {
667 	struct gfs2_sbd *sdp = sb->s_fs_info;
668 
669 	gfs2_quota_sync(sb, -1);
670 	if (wait)
671 		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
672 			       GFS2_LFC_SYNC_FS);
673 	return sdp->sd_log_error;
674 }
675 
676 static int gfs2_do_thaw(struct gfs2_sbd *sdp)
677 {
678 	struct super_block *sb = sdp->sd_vfs;
679 	int error;
680 
681 	error = gfs2_freeze_lock_shared(sdp);
682 	if (error)
683 		goto fail;
684 	error = thaw_super(sb, FREEZE_HOLDER_USERSPACE);
685 	if (!error)
686 		return 0;
687 
688 fail:
689 	fs_info(sdp, "GFS2: couldn't thaw filesystem: %d\n", error);
690 	gfs2_assert_withdraw(sdp, 0);
691 	return error;
692 }
693 
694 void gfs2_freeze_func(struct work_struct *work)
695 {
696 	struct gfs2_sbd *sdp = container_of(work, struct gfs2_sbd, sd_freeze_work);
697 	struct super_block *sb = sdp->sd_vfs;
698 	int error;
699 
700 	mutex_lock(&sdp->sd_freeze_mutex);
701 	error = -EBUSY;
702 	if (test_bit(SDF_FROZEN, &sdp->sd_flags))
703 		goto freeze_failed;
704 
705 	error = freeze_super(sb, FREEZE_HOLDER_USERSPACE);
706 	if (error)
707 		goto freeze_failed;
708 
709 	gfs2_freeze_unlock(&sdp->sd_freeze_gh);
710 	set_bit(SDF_FROZEN, &sdp->sd_flags);
711 
712 	error = gfs2_do_thaw(sdp);
713 	if (error)
714 		goto out;
715 
716 	clear_bit(SDF_FROZEN, &sdp->sd_flags);
717 	goto out;
718 
719 freeze_failed:
720 	fs_info(sdp, "GFS2: couldn't freeze filesystem: %d\n", error);
721 
722 out:
723 	mutex_unlock(&sdp->sd_freeze_mutex);
724 	deactivate_super(sb);
725 }
726 
727 /**
728  * gfs2_freeze_super - prevent further writes to the filesystem
729  * @sb: the VFS structure for the filesystem
730  *
731  */
732 
733 static int gfs2_freeze_super(struct super_block *sb, enum freeze_holder who)
734 {
735 	struct gfs2_sbd *sdp = sb->s_fs_info;
736 	int error;
737 
738 	if (!mutex_trylock(&sdp->sd_freeze_mutex))
739 		return -EBUSY;
740 	if (test_bit(SDF_FROZEN, &sdp->sd_flags)) {
741 		mutex_unlock(&sdp->sd_freeze_mutex);
742 		return -EBUSY;
743 	}
744 
745 	for (;;) {
746 		error = freeze_super(sb, FREEZE_HOLDER_USERSPACE);
747 		if (error) {
748 			fs_info(sdp, "GFS2: couldn't freeze filesystem: %d\n",
749 				error);
750 			goto out;
751 		}
752 
753 		error = gfs2_lock_fs_check_clean(sdp);
754 		if (!error) {
755 			set_bit(SDF_FREEZE_INITIATOR, &sdp->sd_flags);
756 			set_bit(SDF_FROZEN, &sdp->sd_flags);
757 			break;
758 		}
759 
760 		error = gfs2_do_thaw(sdp);
761 		if (error)
762 			goto out;
763 
764 		if (error == -EBUSY)
765 			fs_err(sdp, "waiting for recovery before freeze\n");
766 		else if (error == -EIO) {
767 			fs_err(sdp, "Fatal IO error: cannot freeze gfs2 due "
768 			       "to recovery error.\n");
769 			goto out;
770 		} else {
771 			fs_err(sdp, "error freezing FS: %d\n", error);
772 		}
773 		fs_err(sdp, "retrying...\n");
774 		msleep(1000);
775 	}
776 
777 out:
778 	mutex_unlock(&sdp->sd_freeze_mutex);
779 	return error;
780 }
781 
782 static int gfs2_freeze_fs(struct super_block *sb)
783 {
784 	struct gfs2_sbd *sdp = sb->s_fs_info;
785 
786 	if (test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {
787 		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_FREEZE |
788 			       GFS2_LFC_FREEZE_GO_SYNC);
789 		if (gfs2_withdrawing_or_withdrawn(sdp))
790 			return -EIO;
791 	}
792 	return 0;
793 }
794 
795 /**
796  * gfs2_thaw_super - reallow writes to the filesystem
797  * @sb: the VFS structure for the filesystem
798  *
799  */
800 
801 static int gfs2_thaw_super(struct super_block *sb, enum freeze_holder who)
802 {
803 	struct gfs2_sbd *sdp = sb->s_fs_info;
804 	int error;
805 
806 	if (!mutex_trylock(&sdp->sd_freeze_mutex))
807 		return -EBUSY;
808 	if (!test_bit(SDF_FREEZE_INITIATOR, &sdp->sd_flags)) {
809 		mutex_unlock(&sdp->sd_freeze_mutex);
810 		return -EINVAL;
811 	}
812 
813 	atomic_inc(&sb->s_active);
814 	gfs2_freeze_unlock(&sdp->sd_freeze_gh);
815 
816 	error = gfs2_do_thaw(sdp);
817 
818 	if (!error) {
819 		clear_bit(SDF_FREEZE_INITIATOR, &sdp->sd_flags);
820 		clear_bit(SDF_FROZEN, &sdp->sd_flags);
821 	}
822 	mutex_unlock(&sdp->sd_freeze_mutex);
823 	deactivate_super(sb);
824 	return error;
825 }
826 
827 void gfs2_thaw_freeze_initiator(struct super_block *sb)
828 {
829 	struct gfs2_sbd *sdp = sb->s_fs_info;
830 
831 	mutex_lock(&sdp->sd_freeze_mutex);
832 	if (!test_bit(SDF_FREEZE_INITIATOR, &sdp->sd_flags))
833 		goto out;
834 
835 	gfs2_freeze_unlock(&sdp->sd_freeze_gh);
836 
837 out:
838 	mutex_unlock(&sdp->sd_freeze_mutex);
839 }
840 
841 /**
842  * statfs_slow_fill - fill in the sg for a given RG
843  * @rgd: the RG
844  * @sc: the sc structure
845  *
846  * Returns: 0 on success, -ESTALE if the LVB is invalid
847  */
848 
849 static int statfs_slow_fill(struct gfs2_rgrpd *rgd,
850 			    struct gfs2_statfs_change_host *sc)
851 {
852 	gfs2_rgrp_verify(rgd);
853 	sc->sc_total += rgd->rd_data;
854 	sc->sc_free += rgd->rd_free;
855 	sc->sc_dinodes += rgd->rd_dinodes;
856 	return 0;
857 }
858 
859 /**
860  * gfs2_statfs_slow - Stat a filesystem using asynchronous locking
861  * @sdp: the filesystem
862  * @sc: the sc info that will be returned
863  *
864  * Any error (other than a signal) will cause this routine to fall back
865  * to the synchronous version.
866  *
867  * FIXME: This really shouldn't busy wait like this.
868  *
869  * Returns: errno
870  */
871 
872 static int gfs2_statfs_slow(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
873 {
874 	struct gfs2_rgrpd *rgd_next;
875 	struct gfs2_holder *gha, *gh;
876 	unsigned int slots = 64;
877 	unsigned int x;
878 	int done;
879 	int error = 0, err;
880 
881 	memset(sc, 0, sizeof(struct gfs2_statfs_change_host));
882 	gha = kmalloc_array(slots, sizeof(struct gfs2_holder), GFP_KERNEL);
883 	if (!gha)
884 		return -ENOMEM;
885 	for (x = 0; x < slots; x++)
886 		gfs2_holder_mark_uninitialized(gha + x);
887 
888 	rgd_next = gfs2_rgrpd_get_first(sdp);
889 
890 	for (;;) {
891 		done = 1;
892 
893 		for (x = 0; x < slots; x++) {
894 			gh = gha + x;
895 
896 			if (gfs2_holder_initialized(gh) && gfs2_glock_poll(gh)) {
897 				err = gfs2_glock_wait(gh);
898 				if (err) {
899 					gfs2_holder_uninit(gh);
900 					error = err;
901 				} else {
902 					if (!error) {
903 						struct gfs2_rgrpd *rgd =
904 							gfs2_glock2rgrp(gh->gh_gl);
905 
906 						error = statfs_slow_fill(rgd, sc);
907 					}
908 					gfs2_glock_dq_uninit(gh);
909 				}
910 			}
911 
912 			if (gfs2_holder_initialized(gh))
913 				done = 0;
914 			else if (rgd_next && !error) {
915 				error = gfs2_glock_nq_init(rgd_next->rd_gl,
916 							   LM_ST_SHARED,
917 							   GL_ASYNC,
918 							   gh);
919 				rgd_next = gfs2_rgrpd_get_next(rgd_next);
920 				done = 0;
921 			}
922 
923 			if (signal_pending(current))
924 				error = -ERESTARTSYS;
925 		}
926 
927 		if (done)
928 			break;
929 
930 		yield();
931 	}
932 
933 	kfree(gha);
934 	return error;
935 }
936 
937 /**
938  * gfs2_statfs_i - Do a statfs
939  * @sdp: the filesystem
940  * @sc: the sc structure
941  *
942  * Returns: errno
943  */
944 
945 static int gfs2_statfs_i(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
946 {
947 	struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
948 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
949 
950 	spin_lock(&sdp->sd_statfs_spin);
951 
952 	*sc = *m_sc;
953 	sc->sc_total += l_sc->sc_total;
954 	sc->sc_free += l_sc->sc_free;
955 	sc->sc_dinodes += l_sc->sc_dinodes;
956 
957 	spin_unlock(&sdp->sd_statfs_spin);
958 
959 	if (sc->sc_free < 0)
960 		sc->sc_free = 0;
961 	if (sc->sc_free > sc->sc_total)
962 		sc->sc_free = sc->sc_total;
963 	if (sc->sc_dinodes < 0)
964 		sc->sc_dinodes = 0;
965 
966 	return 0;
967 }
968 
969 /**
970  * gfs2_statfs - Gather and return stats about the filesystem
971  * @dentry: The name of the link
972  * @buf: The buffer
973  *
974  * Returns: 0 on success or error code
975  */
976 
977 static int gfs2_statfs(struct dentry *dentry, struct kstatfs *buf)
978 {
979 	struct super_block *sb = dentry->d_sb;
980 	struct gfs2_sbd *sdp = sb->s_fs_info;
981 	struct gfs2_statfs_change_host sc;
982 	int error;
983 
984 	error = gfs2_rindex_update(sdp);
985 	if (error)
986 		return error;
987 
988 	if (gfs2_tune_get(sdp, gt_statfs_slow))
989 		error = gfs2_statfs_slow(sdp, &sc);
990 	else
991 		error = gfs2_statfs_i(sdp, &sc);
992 
993 	if (error)
994 		return error;
995 
996 	buf->f_type = GFS2_MAGIC;
997 	buf->f_bsize = sdp->sd_sb.sb_bsize;
998 	buf->f_blocks = sc.sc_total;
999 	buf->f_bfree = sc.sc_free;
1000 	buf->f_bavail = sc.sc_free;
1001 	buf->f_files = sc.sc_dinodes + sc.sc_free;
1002 	buf->f_ffree = sc.sc_free;
1003 	buf->f_namelen = GFS2_FNAMESIZE;
1004 	buf->f_fsid = uuid_to_fsid(sb->s_uuid.b);
1005 
1006 	return 0;
1007 }
1008 
1009 /**
1010  * gfs2_drop_inode - Drop an inode (test for remote unlink)
1011  * @inode: The inode to drop
1012  *
1013  * If we've received a callback on an iopen lock then it's because a
1014  * remote node tried to deallocate the inode but failed due to this node
1015  * still having the inode open. Here we mark the link count zero
1016  * since we know that it must have reached zero if the GLF_DEMOTE flag
1017  * is set on the iopen glock. If we didn't do a disk read since the
1018  * remote node removed the final link then we might otherwise miss
1019  * this event. This check ensures that this node will deallocate the
1020  * inode's blocks, or alternatively pass the baton on to another
1021  * node for later deallocation.
1022  */
1023 
1024 static int gfs2_drop_inode(struct inode *inode)
1025 {
1026 	struct gfs2_inode *ip = GFS2_I(inode);
1027 	struct gfs2_sbd *sdp = GFS2_SB(inode);
1028 
1029 	if (inode->i_nlink &&
1030 	    gfs2_holder_initialized(&ip->i_iopen_gh)) {
1031 		struct gfs2_glock *gl = ip->i_iopen_gh.gh_gl;
1032 		if (test_bit(GLF_DEMOTE, &gl->gl_flags))
1033 			clear_nlink(inode);
1034 	}
1035 
1036 	/*
1037 	 * When under memory pressure when an inode's link count has dropped to
1038 	 * zero, defer deleting the inode to the delete workqueue.  This avoids
1039 	 * calling into DLM under memory pressure, which can deadlock.
1040 	 */
1041 	if (!inode->i_nlink &&
1042 	    unlikely(current->flags & PF_MEMALLOC) &&
1043 	    gfs2_holder_initialized(&ip->i_iopen_gh)) {
1044 		struct gfs2_glock *gl = ip->i_iopen_gh.gh_gl;
1045 
1046 		gfs2_glock_hold(gl);
1047 		if (!gfs2_queue_try_to_evict(gl))
1048 			gfs2_glock_queue_put(gl);
1049 		return 0;
1050 	}
1051 
1052 	/*
1053 	 * No longer cache inodes when trying to evict them all.
1054 	 */
1055 	if (test_bit(SDF_EVICTING, &sdp->sd_flags))
1056 		return 1;
1057 
1058 	return generic_drop_inode(inode);
1059 }
1060 
1061 /**
1062  * gfs2_show_options - Show mount options for /proc/mounts
1063  * @s: seq_file structure
1064  * @root: root of this (sub)tree
1065  *
1066  * Returns: 0 on success or error code
1067  */
1068 
1069 static int gfs2_show_options(struct seq_file *s, struct dentry *root)
1070 {
1071 	struct gfs2_sbd *sdp = root->d_sb->s_fs_info;
1072 	struct gfs2_args *args = &sdp->sd_args;
1073 	unsigned int logd_secs, statfs_slow, statfs_quantum, quota_quantum;
1074 
1075 	spin_lock(&sdp->sd_tune.gt_spin);
1076 	logd_secs = sdp->sd_tune.gt_logd_secs;
1077 	quota_quantum = sdp->sd_tune.gt_quota_quantum;
1078 	statfs_quantum = sdp->sd_tune.gt_statfs_quantum;
1079 	statfs_slow = sdp->sd_tune.gt_statfs_slow;
1080 	spin_unlock(&sdp->sd_tune.gt_spin);
1081 
1082 	if (is_subdir(root, sdp->sd_master_dir))
1083 		seq_puts(s, ",meta");
1084 	if (args->ar_lockproto[0])
1085 		seq_show_option(s, "lockproto", args->ar_lockproto);
1086 	if (args->ar_locktable[0])
1087 		seq_show_option(s, "locktable", args->ar_locktable);
1088 	if (args->ar_hostdata[0])
1089 		seq_show_option(s, "hostdata", args->ar_hostdata);
1090 	if (args->ar_spectator)
1091 		seq_puts(s, ",spectator");
1092 	if (args->ar_localflocks)
1093 		seq_puts(s, ",localflocks");
1094 	if (args->ar_debug)
1095 		seq_puts(s, ",debug");
1096 	if (args->ar_posix_acl)
1097 		seq_puts(s, ",acl");
1098 	if (args->ar_quota != GFS2_QUOTA_DEFAULT) {
1099 		char *state;
1100 		switch (args->ar_quota) {
1101 		case GFS2_QUOTA_OFF:
1102 			state = "off";
1103 			break;
1104 		case GFS2_QUOTA_ACCOUNT:
1105 			state = "account";
1106 			break;
1107 		case GFS2_QUOTA_ON:
1108 			state = "on";
1109 			break;
1110 		case GFS2_QUOTA_QUIET:
1111 			state = "quiet";
1112 			break;
1113 		default:
1114 			state = "unknown";
1115 			break;
1116 		}
1117 		seq_printf(s, ",quota=%s", state);
1118 	}
1119 	if (args->ar_suiddir)
1120 		seq_puts(s, ",suiddir");
1121 	if (args->ar_data != GFS2_DATA_DEFAULT) {
1122 		char *state;
1123 		switch (args->ar_data) {
1124 		case GFS2_DATA_WRITEBACK:
1125 			state = "writeback";
1126 			break;
1127 		case GFS2_DATA_ORDERED:
1128 			state = "ordered";
1129 			break;
1130 		default:
1131 			state = "unknown";
1132 			break;
1133 		}
1134 		seq_printf(s, ",data=%s", state);
1135 	}
1136 	if (args->ar_discard)
1137 		seq_puts(s, ",discard");
1138 	if (logd_secs != 30)
1139 		seq_printf(s, ",commit=%d", logd_secs);
1140 	if (statfs_quantum != 30)
1141 		seq_printf(s, ",statfs_quantum=%d", statfs_quantum);
1142 	else if (statfs_slow)
1143 		seq_puts(s, ",statfs_quantum=0");
1144 	if (quota_quantum != 60)
1145 		seq_printf(s, ",quota_quantum=%d", quota_quantum);
1146 	if (args->ar_statfs_percent)
1147 		seq_printf(s, ",statfs_percent=%d", args->ar_statfs_percent);
1148 	if (args->ar_errors != GFS2_ERRORS_DEFAULT) {
1149 		const char *state;
1150 
1151 		switch (args->ar_errors) {
1152 		case GFS2_ERRORS_WITHDRAW:
1153 			state = "withdraw";
1154 			break;
1155 		case GFS2_ERRORS_PANIC:
1156 			state = "panic";
1157 			break;
1158 		default:
1159 			state = "unknown";
1160 			break;
1161 		}
1162 		seq_printf(s, ",errors=%s", state);
1163 	}
1164 	if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags))
1165 		seq_puts(s, ",nobarrier");
1166 	if (test_bit(SDF_DEMOTE, &sdp->sd_flags))
1167 		seq_puts(s, ",demote_interface_used");
1168 	if (args->ar_rgrplvb)
1169 		seq_puts(s, ",rgrplvb");
1170 	if (args->ar_loccookie)
1171 		seq_puts(s, ",loccookie");
1172 	return 0;
1173 }
1174 
1175 static void gfs2_final_release_pages(struct gfs2_inode *ip)
1176 {
1177 	struct inode *inode = &ip->i_inode;
1178 	struct gfs2_glock *gl = ip->i_gl;
1179 
1180 	if (unlikely(!gl)) {
1181 		/* This can only happen during incomplete inode creation. */
1182 		BUG_ON(!test_bit(GIF_ALLOC_FAILED, &ip->i_flags));
1183 		return;
1184 	}
1185 
1186 	truncate_inode_pages(gfs2_glock2aspace(gl), 0);
1187 	truncate_inode_pages(&inode->i_data, 0);
1188 
1189 	if (atomic_read(&gl->gl_revokes) == 0) {
1190 		clear_bit(GLF_LFLUSH, &gl->gl_flags);
1191 		clear_bit(GLF_DIRTY, &gl->gl_flags);
1192 	}
1193 }
1194 
1195 static int gfs2_dinode_dealloc(struct gfs2_inode *ip)
1196 {
1197 	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
1198 	struct gfs2_rgrpd *rgd;
1199 	struct gfs2_holder gh;
1200 	int error;
1201 
1202 	if (gfs2_get_inode_blocks(&ip->i_inode) != 1) {
1203 		gfs2_consist_inode(ip);
1204 		return -EIO;
1205 	}
1206 
1207 	gfs2_rindex_update(sdp);
1208 
1209 	error = gfs2_quota_hold(ip, NO_UID_QUOTA_CHANGE, NO_GID_QUOTA_CHANGE);
1210 	if (error)
1211 		return error;
1212 
1213 	rgd = gfs2_blk2rgrpd(sdp, ip->i_no_addr, 1);
1214 	if (!rgd) {
1215 		gfs2_consist_inode(ip);
1216 		error = -EIO;
1217 		goto out_qs;
1218 	}
1219 
1220 	error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_EXCLUSIVE,
1221 				   LM_FLAG_NODE_SCOPE, &gh);
1222 	if (error)
1223 		goto out_qs;
1224 
1225 	error = gfs2_trans_begin(sdp, RES_RG_BIT + RES_STATFS + RES_QUOTA,
1226 				 sdp->sd_jdesc->jd_blocks);
1227 	if (error)
1228 		goto out_rg_gunlock;
1229 
1230 	gfs2_free_di(rgd, ip);
1231 
1232 	gfs2_final_release_pages(ip);
1233 
1234 	gfs2_trans_end(sdp);
1235 
1236 out_rg_gunlock:
1237 	gfs2_glock_dq_uninit(&gh);
1238 out_qs:
1239 	gfs2_quota_unhold(ip);
1240 	return error;
1241 }
1242 
1243 /**
1244  * gfs2_glock_put_eventually
1245  * @gl:	The glock to put
1246  *
1247  * When under memory pressure, trigger a deferred glock put to make sure we
1248  * won't call into DLM and deadlock.  Otherwise, put the glock directly.
1249  */
1250 
1251 static void gfs2_glock_put_eventually(struct gfs2_glock *gl)
1252 {
1253 	if (current->flags & PF_MEMALLOC)
1254 		gfs2_glock_queue_put(gl);
1255 	else
1256 		gfs2_glock_put(gl);
1257 }
1258 
1259 static bool gfs2_upgrade_iopen_glock(struct inode *inode)
1260 {
1261 	struct gfs2_inode *ip = GFS2_I(inode);
1262 	struct gfs2_sbd *sdp = GFS2_SB(inode);
1263 	struct gfs2_holder *gh = &ip->i_iopen_gh;
1264 	long timeout = 5 * HZ;
1265 	int error;
1266 
1267 	gh->gh_flags |= GL_NOCACHE;
1268 	gfs2_glock_dq_wait(gh);
1269 
1270 	/*
1271 	 * If there are no other lock holders, we will immediately get
1272 	 * exclusive access to the iopen glock here.
1273 	 *
1274 	 * Otherwise, the other nodes holding the lock will be notified about
1275 	 * our locking request.  If they do not have the inode open, they are
1276 	 * expected to evict the cached inode and release the lock, allowing us
1277 	 * to proceed.
1278 	 *
1279 	 * Otherwise, if they cannot evict the inode, they are expected to poke
1280 	 * the inode glock (note: not the iopen glock).  We will notice that
1281 	 * and stop waiting for the iopen glock immediately.  The other node(s)
1282 	 * are then expected to take care of deleting the inode when they no
1283 	 * longer use it.
1284 	 *
1285 	 * As a last resort, if another node keeps holding the iopen glock
1286 	 * without showing any activity on the inode glock, we will eventually
1287 	 * time out and fail the iopen glock upgrade.
1288 	 */
1289 
1290 	gfs2_holder_reinit(LM_ST_EXCLUSIVE, GL_ASYNC | GL_NOCACHE, gh);
1291 	error = gfs2_glock_nq(gh);
1292 	if (error)
1293 		return false;
1294 
1295 	timeout = wait_event_interruptible_timeout(sdp->sd_async_glock_wait,
1296 		!test_bit(HIF_WAIT, &gh->gh_iflags) ||
1297 		test_bit(GLF_DEMOTE, &ip->i_gl->gl_flags),
1298 		timeout);
1299 	if (!test_bit(HIF_HOLDER, &gh->gh_iflags)) {
1300 		gfs2_glock_dq(gh);
1301 		return false;
1302 	}
1303 	return gfs2_glock_holder_ready(gh) == 0;
1304 }
1305 
1306 /**
1307  * evict_should_delete - determine whether the inode is eligible for deletion
1308  * @inode: The inode to evict
1309  * @gh: The glock holder structure
1310  *
1311  * This function determines whether the evicted inode is eligible to be deleted
1312  * and locks the inode glock.
1313  *
1314  * Returns: the fate of the dinode
1315  */
1316 static enum dinode_demise evict_should_delete(struct inode *inode,
1317 					      struct gfs2_holder *gh)
1318 {
1319 	struct gfs2_inode *ip = GFS2_I(inode);
1320 	struct super_block *sb = inode->i_sb;
1321 	struct gfs2_sbd *sdp = sb->s_fs_info;
1322 	int ret;
1323 
1324 	if (unlikely(test_bit(GIF_ALLOC_FAILED, &ip->i_flags)))
1325 		goto should_delete;
1326 
1327 	if (test_bit(GIF_DEFERRED_DELETE, &ip->i_flags))
1328 		return SHOULD_DEFER_EVICTION;
1329 
1330 	/* Deletes should never happen under memory pressure anymore.  */
1331 	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
1332 		return SHOULD_DEFER_EVICTION;
1333 
1334 	/* Must not read inode block until block type has been verified */
1335 	ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_SKIP, gh);
1336 	if (unlikely(ret)) {
1337 		glock_clear_object(ip->i_iopen_gh.gh_gl, ip);
1338 		ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
1339 		gfs2_glock_dq_uninit(&ip->i_iopen_gh);
1340 		return SHOULD_DEFER_EVICTION;
1341 	}
1342 
1343 	if (gfs2_inode_already_deleted(ip->i_gl, ip->i_no_formal_ino))
1344 		return SHOULD_NOT_DELETE_DINODE;
1345 	ret = gfs2_check_blk_type(sdp, ip->i_no_addr, GFS2_BLKST_UNLINKED);
1346 	if (ret)
1347 		return SHOULD_NOT_DELETE_DINODE;
1348 
1349 	ret = gfs2_instantiate(gh);
1350 	if (ret)
1351 		return SHOULD_NOT_DELETE_DINODE;
1352 
1353 	/*
1354 	 * The inode may have been recreated in the meantime.
1355 	 */
1356 	if (inode->i_nlink)
1357 		return SHOULD_NOT_DELETE_DINODE;
1358 
1359 should_delete:
1360 	if (gfs2_holder_initialized(&ip->i_iopen_gh) &&
1361 	    test_bit(HIF_HOLDER, &ip->i_iopen_gh.gh_iflags)) {
1362 		if (!gfs2_upgrade_iopen_glock(inode)) {
1363 			gfs2_holder_uninit(&ip->i_iopen_gh);
1364 			return SHOULD_NOT_DELETE_DINODE;
1365 		}
1366 	}
1367 	return SHOULD_DELETE_DINODE;
1368 }
1369 
1370 /**
1371  * evict_unlinked_inode - delete the pieces of an unlinked evicted inode
1372  * @inode: The inode to evict
1373  */
1374 static int evict_unlinked_inode(struct inode *inode)
1375 {
1376 	struct gfs2_inode *ip = GFS2_I(inode);
1377 	int ret;
1378 
1379 	if (S_ISDIR(inode->i_mode) &&
1380 	    (ip->i_diskflags & GFS2_DIF_EXHASH)) {
1381 		ret = gfs2_dir_exhash_dealloc(ip);
1382 		if (ret)
1383 			goto out;
1384 	}
1385 
1386 	if (ip->i_eattr) {
1387 		ret = gfs2_ea_dealloc(ip);
1388 		if (ret)
1389 			goto out;
1390 	}
1391 
1392 	if (!gfs2_is_stuffed(ip)) {
1393 		ret = gfs2_file_dealloc(ip);
1394 		if (ret)
1395 			goto out;
1396 	}
1397 
1398 	/*
1399 	 * As soon as we clear the bitmap for the dinode, gfs2_create_inode()
1400 	 * can get called to recreate it, or even gfs2_inode_lookup() if the
1401 	 * inode was recreated on another node in the meantime.
1402 	 *
1403 	 * However, inserting the new inode into the inode hash table will not
1404 	 * succeed until the old inode is removed, and that only happens after
1405 	 * ->evict_inode() returns.  The new inode is attached to its inode and
1406 	 *  iopen glocks after inserting it into the inode hash table, so at
1407 	 *  that point we can be sure that both glocks are unused.
1408 	 */
1409 
1410 	ret = gfs2_dinode_dealloc(ip);
1411 	if (!ret && ip->i_gl)
1412 		gfs2_inode_remember_delete(ip->i_gl, ip->i_no_formal_ino);
1413 
1414 out:
1415 	return ret;
1416 }
1417 
1418 /*
1419  * evict_linked_inode - evict an inode whose dinode has not been unlinked
1420  * @inode: The inode to evict
1421  */
1422 static int evict_linked_inode(struct inode *inode)
1423 {
1424 	struct super_block *sb = inode->i_sb;
1425 	struct gfs2_sbd *sdp = sb->s_fs_info;
1426 	struct gfs2_inode *ip = GFS2_I(inode);
1427 	struct address_space *metamapping;
1428 	int ret;
1429 
1430 	gfs2_log_flush(sdp, ip->i_gl, GFS2_LOG_HEAD_FLUSH_NORMAL |
1431 		       GFS2_LFC_EVICT_INODE);
1432 	metamapping = gfs2_glock2aspace(ip->i_gl);
1433 	if (test_bit(GLF_DIRTY, &ip->i_gl->gl_flags)) {
1434 		filemap_fdatawrite(metamapping);
1435 		filemap_fdatawait(metamapping);
1436 	}
1437 	write_inode_now(inode, 1);
1438 	gfs2_ail_flush(ip->i_gl, 0);
1439 
1440 	ret = gfs2_trans_begin(sdp, 0, sdp->sd_jdesc->jd_blocks);
1441 	if (ret)
1442 		return ret;
1443 
1444 	/* Needs to be done before glock release & also in a transaction */
1445 	truncate_inode_pages(&inode->i_data, 0);
1446 	truncate_inode_pages(metamapping, 0);
1447 	gfs2_trans_end(sdp);
1448 	return 0;
1449 }
1450 
1451 /**
1452  * gfs2_evict_inode - Remove an inode from cache
1453  * @inode: The inode to evict
1454  *
1455  * There are three cases to consider:
1456  * 1. i_nlink == 0, we are final opener (and must deallocate)
1457  * 2. i_nlink == 0, we are not the final opener (and cannot deallocate)
1458  * 3. i_nlink > 0
1459  *
1460  * If the fs is read only, then we have to treat all cases as per #3
1461  * since we are unable to do any deallocation. The inode will be
1462  * deallocated by the next read/write node to attempt an allocation
1463  * in the same resource group
1464  *
1465  * We have to (at the moment) hold the inodes main lock to cover
1466  * the gap between unlocking the shared lock on the iopen lock and
1467  * taking the exclusive lock. I'd rather do a shared -> exclusive
1468  * conversion on the iopen lock, but we can change that later. This
1469  * is safe, just less efficient.
1470  */
1471 
1472 static void gfs2_evict_inode(struct inode *inode)
1473 {
1474 	struct super_block *sb = inode->i_sb;
1475 	struct gfs2_sbd *sdp = sb->s_fs_info;
1476 	struct gfs2_inode *ip = GFS2_I(inode);
1477 	struct gfs2_holder gh;
1478 	int ret;
1479 
1480 	if (inode->i_nlink || sb_rdonly(sb) || !ip->i_no_addr)
1481 		goto out;
1482 
1483 	/*
1484 	 * In case of an incomplete mount, gfs2_evict_inode() may be called for
1485 	 * system files without having an active journal to write to.  In that
1486 	 * case, skip the filesystem evict.
1487 	 */
1488 	if (!sdp->sd_jdesc)
1489 		goto out;
1490 
1491 	gfs2_holder_mark_uninitialized(&gh);
1492 	ret = evict_should_delete(inode, &gh);
1493 	if (ret == SHOULD_DEFER_EVICTION)
1494 		goto out;
1495 	if (ret == SHOULD_DELETE_DINODE)
1496 		ret = evict_unlinked_inode(inode);
1497 	else
1498 		ret = evict_linked_inode(inode);
1499 
1500 	if (gfs2_rs_active(&ip->i_res))
1501 		gfs2_rs_deltree(&ip->i_res);
1502 
1503 	if (gfs2_holder_initialized(&gh))
1504 		gfs2_glock_dq_uninit(&gh);
1505 	if (ret && ret != GLR_TRYFAILED && ret != -EROFS)
1506 		fs_warn(sdp, "gfs2_evict_inode: %d\n", ret);
1507 out:
1508 	truncate_inode_pages_final(&inode->i_data);
1509 	if (ip->i_qadata)
1510 		gfs2_assert_warn(sdp, ip->i_qadata->qa_ref == 0);
1511 	gfs2_rs_deltree(&ip->i_res);
1512 	gfs2_ordered_del_inode(ip);
1513 	clear_inode(inode);
1514 	gfs2_dir_hash_inval(ip);
1515 	if (gfs2_holder_initialized(&ip->i_iopen_gh)) {
1516 		struct gfs2_glock *gl = ip->i_iopen_gh.gh_gl;
1517 
1518 		glock_clear_object(gl, ip);
1519 		gfs2_glock_hold(gl);
1520 		ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
1521 		gfs2_glock_dq_uninit(&ip->i_iopen_gh);
1522 		gfs2_glock_put_eventually(gl);
1523 	}
1524 	if (ip->i_gl) {
1525 		glock_clear_object(ip->i_gl, ip);
1526 		wait_on_bit_io(&ip->i_flags, GIF_GLOP_PENDING, TASK_UNINTERRUPTIBLE);
1527 		gfs2_glock_add_to_lru(ip->i_gl);
1528 		gfs2_glock_put_eventually(ip->i_gl);
1529 		rcu_assign_pointer(ip->i_gl, NULL);
1530 	}
1531 }
1532 
1533 static struct inode *gfs2_alloc_inode(struct super_block *sb)
1534 {
1535 	struct gfs2_inode *ip;
1536 
1537 	ip = alloc_inode_sb(sb, gfs2_inode_cachep, GFP_KERNEL);
1538 	if (!ip)
1539 		return NULL;
1540 	ip->i_no_addr = 0;
1541 	ip->i_flags = 0;
1542 	ip->i_gl = NULL;
1543 	gfs2_holder_mark_uninitialized(&ip->i_iopen_gh);
1544 	memset(&ip->i_res, 0, sizeof(ip->i_res));
1545 	RB_CLEAR_NODE(&ip->i_res.rs_node);
1546 	ip->i_rahead = 0;
1547 	return &ip->i_inode;
1548 }
1549 
1550 static void gfs2_free_inode(struct inode *inode)
1551 {
1552 	kmem_cache_free(gfs2_inode_cachep, GFS2_I(inode));
1553 }
1554 
1555 void free_local_statfs_inodes(struct gfs2_sbd *sdp)
1556 {
1557 	struct local_statfs_inode *lsi, *safe;
1558 
1559 	/* Run through the statfs inodes list to iput and free memory */
1560 	list_for_each_entry_safe(lsi, safe, &sdp->sd_sc_inodes_list, si_list) {
1561 		if (lsi->si_jid == sdp->sd_jdesc->jd_jid)
1562 			sdp->sd_sc_inode = NULL; /* belongs to this node */
1563 		if (lsi->si_sc_inode)
1564 			iput(lsi->si_sc_inode);
1565 		list_del(&lsi->si_list);
1566 		kfree(lsi);
1567 	}
1568 }
1569 
1570 struct inode *find_local_statfs_inode(struct gfs2_sbd *sdp,
1571 				      unsigned int index)
1572 {
1573 	struct local_statfs_inode *lsi;
1574 
1575 	/* Return the local (per node) statfs inode in the
1576 	 * sdp->sd_sc_inodes_list corresponding to the 'index'. */
1577 	list_for_each_entry(lsi, &sdp->sd_sc_inodes_list, si_list) {
1578 		if (lsi->si_jid == index)
1579 			return lsi->si_sc_inode;
1580 	}
1581 	return NULL;
1582 }
1583 
1584 const struct super_operations gfs2_super_ops = {
1585 	.alloc_inode		= gfs2_alloc_inode,
1586 	.free_inode		= gfs2_free_inode,
1587 	.write_inode		= gfs2_write_inode,
1588 	.dirty_inode		= gfs2_dirty_inode,
1589 	.evict_inode		= gfs2_evict_inode,
1590 	.put_super		= gfs2_put_super,
1591 	.sync_fs		= gfs2_sync_fs,
1592 	.freeze_super		= gfs2_freeze_super,
1593 	.freeze_fs		= gfs2_freeze_fs,
1594 	.thaw_super		= gfs2_thaw_super,
1595 	.statfs			= gfs2_statfs,
1596 	.drop_inode		= gfs2_drop_inode,
1597 	.show_options		= gfs2_show_options,
1598 };
1599 
1600