xref: /openbmc/linux/fs/gfs2/super.c (revision 2d99a7ec)
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_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_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;
336 
337 	list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
338 		lfcc = kmalloc(sizeof(struct lfcc), GFP_KERNEL);
339 		if (!lfcc) {
340 			error = -ENOMEM;
341 			goto out;
342 		}
343 		ip = GFS2_I(jd->jd_inode);
344 		error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &lfcc->gh);
345 		if (error) {
346 			kfree(lfcc);
347 			goto out;
348 		}
349 		list_add(&lfcc->list, &list);
350 	}
351 
352 	error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_EXCLUSIVE,
353 				   LM_FLAG_NOEXP | GL_NOPID,
354 				   &sdp->sd_freeze_gh);
355 	if (error)
356 		goto out;
357 
358 	list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
359 		error = gfs2_jdesc_check(jd);
360 		if (error)
361 			break;
362 		error = gfs2_find_jhead(jd, &lh, false);
363 		if (error)
364 			break;
365 		if (!(lh.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
366 			error = -EBUSY;
367 			break;
368 		}
369 	}
370 
371 	if (error)
372 		gfs2_freeze_unlock(&sdp->sd_freeze_gh);
373 
374 out:
375 	while (!list_empty(&list)) {
376 		lfcc = list_first_entry(&list, struct lfcc, list);
377 		list_del(&lfcc->list);
378 		gfs2_glock_dq_uninit(&lfcc->gh);
379 		kfree(lfcc);
380 	}
381 	return error;
382 }
383 
384 void gfs2_dinode_out(const struct gfs2_inode *ip, void *buf)
385 {
386 	const struct inode *inode = &ip->i_inode;
387 	struct gfs2_dinode *str = buf;
388 
389 	str->di_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
390 	str->di_header.mh_type = cpu_to_be32(GFS2_METATYPE_DI);
391 	str->di_header.mh_format = cpu_to_be32(GFS2_FORMAT_DI);
392 	str->di_num.no_addr = cpu_to_be64(ip->i_no_addr);
393 	str->di_num.no_formal_ino = cpu_to_be64(ip->i_no_formal_ino);
394 	str->di_mode = cpu_to_be32(inode->i_mode);
395 	str->di_uid = cpu_to_be32(i_uid_read(inode));
396 	str->di_gid = cpu_to_be32(i_gid_read(inode));
397 	str->di_nlink = cpu_to_be32(inode->i_nlink);
398 	str->di_size = cpu_to_be64(i_size_read(inode));
399 	str->di_blocks = cpu_to_be64(gfs2_get_inode_blocks(inode));
400 	str->di_atime = cpu_to_be64(inode->i_atime.tv_sec);
401 	str->di_mtime = cpu_to_be64(inode->i_mtime.tv_sec);
402 	str->di_ctime = cpu_to_be64(inode->i_ctime.tv_sec);
403 
404 	str->di_goal_meta = cpu_to_be64(ip->i_goal);
405 	str->di_goal_data = cpu_to_be64(ip->i_goal);
406 	str->di_generation = cpu_to_be64(ip->i_generation);
407 
408 	str->di_flags = cpu_to_be32(ip->i_diskflags);
409 	str->di_height = cpu_to_be16(ip->i_height);
410 	str->di_payload_format = cpu_to_be32(S_ISDIR(inode->i_mode) &&
411 					     !(ip->i_diskflags & GFS2_DIF_EXHASH) ?
412 					     GFS2_FORMAT_DE : 0);
413 	str->di_depth = cpu_to_be16(ip->i_depth);
414 	str->di_entries = cpu_to_be32(ip->i_entries);
415 
416 	str->di_eattr = cpu_to_be64(ip->i_eattr);
417 	str->di_atime_nsec = cpu_to_be32(inode->i_atime.tv_nsec);
418 	str->di_mtime_nsec = cpu_to_be32(inode->i_mtime.tv_nsec);
419 	str->di_ctime_nsec = cpu_to_be32(inode->i_ctime.tv_nsec);
420 }
421 
422 /**
423  * gfs2_write_inode - Make sure the inode is stable on the disk
424  * @inode: The inode
425  * @wbc: The writeback control structure
426  *
427  * Returns: errno
428  */
429 
430 static int gfs2_write_inode(struct inode *inode, struct writeback_control *wbc)
431 {
432 	struct gfs2_inode *ip = GFS2_I(inode);
433 	struct gfs2_sbd *sdp = GFS2_SB(inode);
434 	struct address_space *metamapping = gfs2_glock2aspace(ip->i_gl);
435 	struct backing_dev_info *bdi = inode_to_bdi(metamapping->host);
436 	int ret = 0;
437 	bool flush_all = (wbc->sync_mode == WB_SYNC_ALL || gfs2_is_jdata(ip));
438 
439 	if (flush_all)
440 		gfs2_log_flush(GFS2_SB(inode), ip->i_gl,
441 			       GFS2_LOG_HEAD_FLUSH_NORMAL |
442 			       GFS2_LFC_WRITE_INODE);
443 	if (bdi->wb.dirty_exceeded)
444 		gfs2_ail1_flush(sdp, wbc);
445 	else
446 		filemap_fdatawrite(metamapping);
447 	if (flush_all)
448 		ret = filemap_fdatawait(metamapping);
449 	if (ret)
450 		mark_inode_dirty_sync(inode);
451 	else {
452 		spin_lock(&inode->i_lock);
453 		if (!(inode->i_flags & I_DIRTY))
454 			gfs2_ordered_del_inode(ip);
455 		spin_unlock(&inode->i_lock);
456 	}
457 	return ret;
458 }
459 
460 /**
461  * gfs2_dirty_inode - check for atime updates
462  * @inode: The inode in question
463  * @flags: The type of dirty
464  *
465  * Unfortunately it can be called under any combination of inode
466  * glock and transaction lock, so we have to check carefully.
467  *
468  * At the moment this deals only with atime - it should be possible
469  * to expand that role in future, once a review of the locking has
470  * been carried out.
471  */
472 
473 static void gfs2_dirty_inode(struct inode *inode, int flags)
474 {
475 	struct gfs2_inode *ip = GFS2_I(inode);
476 	struct gfs2_sbd *sdp = GFS2_SB(inode);
477 	struct buffer_head *bh;
478 	struct gfs2_holder gh;
479 	int need_unlock = 0;
480 	int need_endtrans = 0;
481 	int ret;
482 
483 	if (unlikely(!ip->i_gl)) {
484 		/* This can only happen during incomplete inode creation. */
485 		BUG_ON(!test_bit(GIF_ALLOC_FAILED, &ip->i_flags));
486 		return;
487 	}
488 
489 	if (unlikely(gfs2_withdrawn(sdp)))
490 		return;
491 	if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
492 		ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
493 		if (ret) {
494 			fs_err(sdp, "dirty_inode: glock %d\n", ret);
495 			gfs2_dump_glock(NULL, ip->i_gl, true);
496 			return;
497 		}
498 		need_unlock = 1;
499 	} else if (WARN_ON_ONCE(ip->i_gl->gl_state != LM_ST_EXCLUSIVE))
500 		return;
501 
502 	if (current->journal_info == NULL) {
503 		ret = gfs2_trans_begin(sdp, RES_DINODE, 0);
504 		if (ret) {
505 			fs_err(sdp, "dirty_inode: gfs2_trans_begin %d\n", ret);
506 			goto out;
507 		}
508 		need_endtrans = 1;
509 	}
510 
511 	ret = gfs2_meta_inode_buffer(ip, &bh);
512 	if (ret == 0) {
513 		gfs2_trans_add_meta(ip->i_gl, bh);
514 		gfs2_dinode_out(ip, bh->b_data);
515 		brelse(bh);
516 	}
517 
518 	if (need_endtrans)
519 		gfs2_trans_end(sdp);
520 out:
521 	if (need_unlock)
522 		gfs2_glock_dq_uninit(&gh);
523 }
524 
525 /**
526  * gfs2_make_fs_ro - Turn a Read-Write FS into a Read-Only one
527  * @sdp: the filesystem
528  *
529  * Returns: errno
530  */
531 
532 void gfs2_make_fs_ro(struct gfs2_sbd *sdp)
533 {
534 	int log_write_allowed = test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
535 
536 	if (!test_bit(SDF_DEACTIVATING, &sdp->sd_flags))
537 		gfs2_flush_delete_work(sdp);
538 
539 	if (!log_write_allowed && current == sdp->sd_quotad_process)
540 		fs_warn(sdp, "The quotad daemon is withdrawing.\n");
541 	else if (sdp->sd_quotad_process)
542 		kthread_stop(sdp->sd_quotad_process);
543 	sdp->sd_quotad_process = NULL;
544 
545 	if (!log_write_allowed && current == sdp->sd_logd_process)
546 		fs_warn(sdp, "The logd daemon is withdrawing.\n");
547 	else if (sdp->sd_logd_process)
548 		kthread_stop(sdp->sd_logd_process);
549 	sdp->sd_logd_process = NULL;
550 
551 	if (log_write_allowed) {
552 		gfs2_quota_sync(sdp->sd_vfs, 0);
553 		gfs2_statfs_sync(sdp->sd_vfs, 0);
554 
555 		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_SHUTDOWN |
556 			       GFS2_LFC_MAKE_FS_RO);
557 		wait_event_timeout(sdp->sd_log_waitq,
558 				   gfs2_log_is_empty(sdp),
559 				   HZ * 5);
560 		gfs2_assert_warn(sdp, gfs2_log_is_empty(sdp));
561 	} else {
562 		wait_event_timeout(sdp->sd_log_waitq,
563 				   gfs2_log_is_empty(sdp),
564 				   HZ * 5);
565 	}
566 	gfs2_quota_cleanup(sdp);
567 
568 	if (!log_write_allowed)
569 		sdp->sd_vfs->s_flags |= SB_RDONLY;
570 }
571 
572 /**
573  * gfs2_put_super - Unmount the filesystem
574  * @sb: The VFS superblock
575  *
576  */
577 
578 static void gfs2_put_super(struct super_block *sb)
579 {
580 	struct gfs2_sbd *sdp = sb->s_fs_info;
581 	struct gfs2_jdesc *jd;
582 
583 	/* No more recovery requests */
584 	set_bit(SDF_NORECOVERY, &sdp->sd_flags);
585 	smp_mb();
586 
587 	/* Wait on outstanding recovery */
588 restart:
589 	spin_lock(&sdp->sd_jindex_spin);
590 	list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
591 		if (!test_bit(JDF_RECOVERY, &jd->jd_flags))
592 			continue;
593 		spin_unlock(&sdp->sd_jindex_spin);
594 		wait_on_bit(&jd->jd_flags, JDF_RECOVERY,
595 			    TASK_UNINTERRUPTIBLE);
596 		goto restart;
597 	}
598 	spin_unlock(&sdp->sd_jindex_spin);
599 
600 	if (!sb_rdonly(sb)) {
601 		gfs2_make_fs_ro(sdp);
602 	}
603 	WARN_ON(gfs2_withdrawing(sdp));
604 
605 	/*  At this point, we're through modifying the disk  */
606 
607 	/*  Release stuff  */
608 
609 	iput(sdp->sd_jindex);
610 	iput(sdp->sd_statfs_inode);
611 	iput(sdp->sd_rindex);
612 	iput(sdp->sd_quota_inode);
613 
614 	gfs2_glock_put(sdp->sd_rename_gl);
615 	gfs2_glock_put(sdp->sd_freeze_gl);
616 
617 	if (!sdp->sd_args.ar_spectator) {
618 		if (gfs2_holder_initialized(&sdp->sd_journal_gh))
619 			gfs2_glock_dq_uninit(&sdp->sd_journal_gh);
620 		if (gfs2_holder_initialized(&sdp->sd_jinode_gh))
621 			gfs2_glock_dq_uninit(&sdp->sd_jinode_gh);
622 		brelse(sdp->sd_sc_bh);
623 		gfs2_glock_dq_uninit(&sdp->sd_sc_gh);
624 		gfs2_glock_dq_uninit(&sdp->sd_qc_gh);
625 		free_local_statfs_inodes(sdp);
626 		iput(sdp->sd_qc_inode);
627 	}
628 
629 	gfs2_glock_dq_uninit(&sdp->sd_live_gh);
630 	gfs2_clear_rgrpd(sdp);
631 	gfs2_jindex_free(sdp);
632 	/*  Take apart glock structures and buffer lists  */
633 	gfs2_gl_hash_clear(sdp);
634 	truncate_inode_pages_final(&sdp->sd_aspace);
635 	gfs2_delete_debugfs_file(sdp);
636 	/*  Unmount the locking protocol  */
637 	gfs2_lm_unmount(sdp);
638 
639 	/*  At this point, we're through participating in the lockspace  */
640 	gfs2_sys_fs_del(sdp);
641 	free_sbd(sdp);
642 }
643 
644 /**
645  * gfs2_sync_fs - sync the filesystem
646  * @sb: the superblock
647  * @wait: true to wait for completion
648  *
649  * Flushes the log to disk.
650  */
651 
652 static int gfs2_sync_fs(struct super_block *sb, int wait)
653 {
654 	struct gfs2_sbd *sdp = sb->s_fs_info;
655 
656 	gfs2_quota_sync(sb, -1);
657 	if (wait)
658 		gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_NORMAL |
659 			       GFS2_LFC_SYNC_FS);
660 	return sdp->sd_log_error;
661 }
662 
663 void gfs2_freeze_func(struct work_struct *work)
664 {
665 	int error;
666 	struct gfs2_holder freeze_gh;
667 	struct gfs2_sbd *sdp = container_of(work, struct gfs2_sbd, sd_freeze_work);
668 	struct super_block *sb = sdp->sd_vfs;
669 
670 	atomic_inc(&sb->s_active);
671 	error = gfs2_freeze_lock(sdp, &freeze_gh, 0);
672 	if (error) {
673 		gfs2_assert_withdraw(sdp, 0);
674 	} else {
675 		atomic_set(&sdp->sd_freeze_state, SFS_UNFROZEN);
676 		error = thaw_super(sb);
677 		if (error) {
678 			fs_info(sdp, "GFS2: couldn't thaw filesystem: %d\n",
679 				error);
680 			gfs2_assert_withdraw(sdp, 0);
681 		}
682 		gfs2_freeze_unlock(&freeze_gh);
683 	}
684 	deactivate_super(sb);
685 	clear_bit_unlock(SDF_FS_FROZEN, &sdp->sd_flags);
686 	wake_up_bit(&sdp->sd_flags, SDF_FS_FROZEN);
687 	return;
688 }
689 
690 /**
691  * gfs2_freeze - prevent further writes to the filesystem
692  * @sb: the VFS structure for the filesystem
693  *
694  */
695 
696 static int gfs2_freeze(struct super_block *sb)
697 {
698 	struct gfs2_sbd *sdp = sb->s_fs_info;
699 	int error;
700 
701 	mutex_lock(&sdp->sd_freeze_mutex);
702 	if (atomic_read(&sdp->sd_freeze_state) != SFS_UNFROZEN) {
703 		error = -EBUSY;
704 		goto out;
705 	}
706 
707 	for (;;) {
708 		if (gfs2_withdrawn(sdp)) {
709 			error = -EINVAL;
710 			goto out;
711 		}
712 
713 		error = gfs2_lock_fs_check_clean(sdp);
714 		if (!error)
715 			break;
716 
717 		if (error == -EBUSY)
718 			fs_err(sdp, "waiting for recovery before freeze\n");
719 		else if (error == -EIO) {
720 			fs_err(sdp, "Fatal IO error: cannot freeze gfs2 due "
721 			       "to recovery error.\n");
722 			goto out;
723 		} else {
724 			fs_err(sdp, "error freezing FS: %d\n", error);
725 		}
726 		fs_err(sdp, "retrying...\n");
727 		msleep(1000);
728 	}
729 	set_bit(SDF_FS_FROZEN, &sdp->sd_flags);
730 out:
731 	mutex_unlock(&sdp->sd_freeze_mutex);
732 	return error;
733 }
734 
735 /**
736  * gfs2_unfreeze - reallow writes to the filesystem
737  * @sb: the VFS structure for the filesystem
738  *
739  */
740 
741 static int gfs2_unfreeze(struct super_block *sb)
742 {
743 	struct gfs2_sbd *sdp = sb->s_fs_info;
744 
745 	mutex_lock(&sdp->sd_freeze_mutex);
746 	if (atomic_read(&sdp->sd_freeze_state) != SFS_FROZEN ||
747 	    !gfs2_holder_initialized(&sdp->sd_freeze_gh)) {
748 		mutex_unlock(&sdp->sd_freeze_mutex);
749 		return -EINVAL;
750 	}
751 
752 	gfs2_freeze_unlock(&sdp->sd_freeze_gh);
753 	mutex_unlock(&sdp->sd_freeze_mutex);
754 	return wait_on_bit(&sdp->sd_flags, SDF_FS_FROZEN, TASK_INTERRUPTIBLE);
755 }
756 
757 /**
758  * statfs_slow_fill - fill in the sg for a given RG
759  * @rgd: the RG
760  * @sc: the sc structure
761  *
762  * Returns: 0 on success, -ESTALE if the LVB is invalid
763  */
764 
765 static int statfs_slow_fill(struct gfs2_rgrpd *rgd,
766 			    struct gfs2_statfs_change_host *sc)
767 {
768 	gfs2_rgrp_verify(rgd);
769 	sc->sc_total += rgd->rd_data;
770 	sc->sc_free += rgd->rd_free;
771 	sc->sc_dinodes += rgd->rd_dinodes;
772 	return 0;
773 }
774 
775 /**
776  * gfs2_statfs_slow - Stat a filesystem using asynchronous locking
777  * @sdp: the filesystem
778  * @sc: the sc info that will be returned
779  *
780  * Any error (other than a signal) will cause this routine to fall back
781  * to the synchronous version.
782  *
783  * FIXME: This really shouldn't busy wait like this.
784  *
785  * Returns: errno
786  */
787 
788 static int gfs2_statfs_slow(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
789 {
790 	struct gfs2_rgrpd *rgd_next;
791 	struct gfs2_holder *gha, *gh;
792 	unsigned int slots = 64;
793 	unsigned int x;
794 	int done;
795 	int error = 0, err;
796 
797 	memset(sc, 0, sizeof(struct gfs2_statfs_change_host));
798 	gha = kmalloc_array(slots, sizeof(struct gfs2_holder), GFP_KERNEL);
799 	if (!gha)
800 		return -ENOMEM;
801 	for (x = 0; x < slots; x++)
802 		gfs2_holder_mark_uninitialized(gha + x);
803 
804 	rgd_next = gfs2_rgrpd_get_first(sdp);
805 
806 	for (;;) {
807 		done = 1;
808 
809 		for (x = 0; x < slots; x++) {
810 			gh = gha + x;
811 
812 			if (gfs2_holder_initialized(gh) && gfs2_glock_poll(gh)) {
813 				err = gfs2_glock_wait(gh);
814 				if (err) {
815 					gfs2_holder_uninit(gh);
816 					error = err;
817 				} else {
818 					if (!error) {
819 						struct gfs2_rgrpd *rgd =
820 							gfs2_glock2rgrp(gh->gh_gl);
821 
822 						error = statfs_slow_fill(rgd, sc);
823 					}
824 					gfs2_glock_dq_uninit(gh);
825 				}
826 			}
827 
828 			if (gfs2_holder_initialized(gh))
829 				done = 0;
830 			else if (rgd_next && !error) {
831 				error = gfs2_glock_nq_init(rgd_next->rd_gl,
832 							   LM_ST_SHARED,
833 							   GL_ASYNC,
834 							   gh);
835 				rgd_next = gfs2_rgrpd_get_next(rgd_next);
836 				done = 0;
837 			}
838 
839 			if (signal_pending(current))
840 				error = -ERESTARTSYS;
841 		}
842 
843 		if (done)
844 			break;
845 
846 		yield();
847 	}
848 
849 	kfree(gha);
850 	return error;
851 }
852 
853 /**
854  * gfs2_statfs_i - Do a statfs
855  * @sdp: the filesystem
856  * @sc: the sc structure
857  *
858  * Returns: errno
859  */
860 
861 static int gfs2_statfs_i(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
862 {
863 	struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
864 	struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
865 
866 	spin_lock(&sdp->sd_statfs_spin);
867 
868 	*sc = *m_sc;
869 	sc->sc_total += l_sc->sc_total;
870 	sc->sc_free += l_sc->sc_free;
871 	sc->sc_dinodes += l_sc->sc_dinodes;
872 
873 	spin_unlock(&sdp->sd_statfs_spin);
874 
875 	if (sc->sc_free < 0)
876 		sc->sc_free = 0;
877 	if (sc->sc_free > sc->sc_total)
878 		sc->sc_free = sc->sc_total;
879 	if (sc->sc_dinodes < 0)
880 		sc->sc_dinodes = 0;
881 
882 	return 0;
883 }
884 
885 /**
886  * gfs2_statfs - Gather and return stats about the filesystem
887  * @dentry: The name of the link
888  * @buf: The buffer
889  *
890  * Returns: 0 on success or error code
891  */
892 
893 static int gfs2_statfs(struct dentry *dentry, struct kstatfs *buf)
894 {
895 	struct super_block *sb = dentry->d_sb;
896 	struct gfs2_sbd *sdp = sb->s_fs_info;
897 	struct gfs2_statfs_change_host sc;
898 	int error;
899 
900 	error = gfs2_rindex_update(sdp);
901 	if (error)
902 		return error;
903 
904 	if (gfs2_tune_get(sdp, gt_statfs_slow))
905 		error = gfs2_statfs_slow(sdp, &sc);
906 	else
907 		error = gfs2_statfs_i(sdp, &sc);
908 
909 	if (error)
910 		return error;
911 
912 	buf->f_type = GFS2_MAGIC;
913 	buf->f_bsize = sdp->sd_sb.sb_bsize;
914 	buf->f_blocks = sc.sc_total;
915 	buf->f_bfree = sc.sc_free;
916 	buf->f_bavail = sc.sc_free;
917 	buf->f_files = sc.sc_dinodes + sc.sc_free;
918 	buf->f_ffree = sc.sc_free;
919 	buf->f_namelen = GFS2_FNAMESIZE;
920 
921 	return 0;
922 }
923 
924 /**
925  * gfs2_drop_inode - Drop an inode (test for remote unlink)
926  * @inode: The inode to drop
927  *
928  * If we've received a callback on an iopen lock then it's because a
929  * remote node tried to deallocate the inode but failed due to this node
930  * still having the inode open. Here we mark the link count zero
931  * since we know that it must have reached zero if the GLF_DEMOTE flag
932  * is set on the iopen glock. If we didn't do a disk read since the
933  * remote node removed the final link then we might otherwise miss
934  * this event. This check ensures that this node will deallocate the
935  * inode's blocks, or alternatively pass the baton on to another
936  * node for later deallocation.
937  */
938 
939 static int gfs2_drop_inode(struct inode *inode)
940 {
941 	struct gfs2_inode *ip = GFS2_I(inode);
942 	struct gfs2_sbd *sdp = GFS2_SB(inode);
943 
944 	if (inode->i_nlink &&
945 	    gfs2_holder_initialized(&ip->i_iopen_gh)) {
946 		struct gfs2_glock *gl = ip->i_iopen_gh.gh_gl;
947 		if (test_bit(GLF_DEMOTE, &gl->gl_flags))
948 			clear_nlink(inode);
949 	}
950 
951 	/*
952 	 * When under memory pressure when an inode's link count has dropped to
953 	 * zero, defer deleting the inode to the delete workqueue.  This avoids
954 	 * calling into DLM under memory pressure, which can deadlock.
955 	 */
956 	if (!inode->i_nlink &&
957 	    unlikely(current->flags & PF_MEMALLOC) &&
958 	    gfs2_holder_initialized(&ip->i_iopen_gh)) {
959 		struct gfs2_glock *gl = ip->i_iopen_gh.gh_gl;
960 
961 		gfs2_glock_hold(gl);
962 		if (!gfs2_queue_try_to_evict(gl))
963 			gfs2_glock_queue_put(gl);
964 		return 0;
965 	}
966 
967 	/*
968 	 * No longer cache inodes when trying to evict them all.
969 	 */
970 	if (test_bit(SDF_EVICTING, &sdp->sd_flags))
971 		return 1;
972 
973 	return generic_drop_inode(inode);
974 }
975 
976 static int is_ancestor(const struct dentry *d1, const struct dentry *d2)
977 {
978 	do {
979 		if (d1 == d2)
980 			return 1;
981 		d1 = d1->d_parent;
982 	} while (!IS_ROOT(d1));
983 	return 0;
984 }
985 
986 /**
987  * gfs2_show_options - Show mount options for /proc/mounts
988  * @s: seq_file structure
989  * @root: root of this (sub)tree
990  *
991  * Returns: 0 on success or error code
992  */
993 
994 static int gfs2_show_options(struct seq_file *s, struct dentry *root)
995 {
996 	struct gfs2_sbd *sdp = root->d_sb->s_fs_info;
997 	struct gfs2_args *args = &sdp->sd_args;
998 	int val;
999 
1000 	if (is_ancestor(root, sdp->sd_master_dir))
1001 		seq_puts(s, ",meta");
1002 	if (args->ar_lockproto[0])
1003 		seq_show_option(s, "lockproto", args->ar_lockproto);
1004 	if (args->ar_locktable[0])
1005 		seq_show_option(s, "locktable", args->ar_locktable);
1006 	if (args->ar_hostdata[0])
1007 		seq_show_option(s, "hostdata", args->ar_hostdata);
1008 	if (args->ar_spectator)
1009 		seq_puts(s, ",spectator");
1010 	if (args->ar_localflocks)
1011 		seq_puts(s, ",localflocks");
1012 	if (args->ar_debug)
1013 		seq_puts(s, ",debug");
1014 	if (args->ar_posix_acl)
1015 		seq_puts(s, ",acl");
1016 	if (args->ar_quota != GFS2_QUOTA_DEFAULT) {
1017 		char *state;
1018 		switch (args->ar_quota) {
1019 		case GFS2_QUOTA_OFF:
1020 			state = "off";
1021 			break;
1022 		case GFS2_QUOTA_ACCOUNT:
1023 			state = "account";
1024 			break;
1025 		case GFS2_QUOTA_ON:
1026 			state = "on";
1027 			break;
1028 		default:
1029 			state = "unknown";
1030 			break;
1031 		}
1032 		seq_printf(s, ",quota=%s", state);
1033 	}
1034 	if (args->ar_suiddir)
1035 		seq_puts(s, ",suiddir");
1036 	if (args->ar_data != GFS2_DATA_DEFAULT) {
1037 		char *state;
1038 		switch (args->ar_data) {
1039 		case GFS2_DATA_WRITEBACK:
1040 			state = "writeback";
1041 			break;
1042 		case GFS2_DATA_ORDERED:
1043 			state = "ordered";
1044 			break;
1045 		default:
1046 			state = "unknown";
1047 			break;
1048 		}
1049 		seq_printf(s, ",data=%s", state);
1050 	}
1051 	if (args->ar_discard)
1052 		seq_puts(s, ",discard");
1053 	val = sdp->sd_tune.gt_logd_secs;
1054 	if (val != 30)
1055 		seq_printf(s, ",commit=%d", val);
1056 	val = sdp->sd_tune.gt_statfs_quantum;
1057 	if (val != 30)
1058 		seq_printf(s, ",statfs_quantum=%d", val);
1059 	else if (sdp->sd_tune.gt_statfs_slow)
1060 		seq_puts(s, ",statfs_quantum=0");
1061 	val = sdp->sd_tune.gt_quota_quantum;
1062 	if (val != 60)
1063 		seq_printf(s, ",quota_quantum=%d", val);
1064 	if (args->ar_statfs_percent)
1065 		seq_printf(s, ",statfs_percent=%d", args->ar_statfs_percent);
1066 	if (args->ar_errors != GFS2_ERRORS_DEFAULT) {
1067 		const char *state;
1068 
1069 		switch (args->ar_errors) {
1070 		case GFS2_ERRORS_WITHDRAW:
1071 			state = "withdraw";
1072 			break;
1073 		case GFS2_ERRORS_PANIC:
1074 			state = "panic";
1075 			break;
1076 		default:
1077 			state = "unknown";
1078 			break;
1079 		}
1080 		seq_printf(s, ",errors=%s", state);
1081 	}
1082 	if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags))
1083 		seq_puts(s, ",nobarrier");
1084 	if (test_bit(SDF_DEMOTE, &sdp->sd_flags))
1085 		seq_puts(s, ",demote_interface_used");
1086 	if (args->ar_rgrplvb)
1087 		seq_puts(s, ",rgrplvb");
1088 	if (args->ar_loccookie)
1089 		seq_puts(s, ",loccookie");
1090 	return 0;
1091 }
1092 
1093 static void gfs2_final_release_pages(struct gfs2_inode *ip)
1094 {
1095 	struct inode *inode = &ip->i_inode;
1096 	struct gfs2_glock *gl = ip->i_gl;
1097 
1098 	if (unlikely(!gl)) {
1099 		/* This can only happen during incomplete inode creation. */
1100 		BUG_ON(!test_bit(GIF_ALLOC_FAILED, &ip->i_flags));
1101 		return;
1102 	}
1103 
1104 	truncate_inode_pages(gfs2_glock2aspace(gl), 0);
1105 	truncate_inode_pages(&inode->i_data, 0);
1106 
1107 	if (atomic_read(&gl->gl_revokes) == 0) {
1108 		clear_bit(GLF_LFLUSH, &gl->gl_flags);
1109 		clear_bit(GLF_DIRTY, &gl->gl_flags);
1110 	}
1111 }
1112 
1113 static int gfs2_dinode_dealloc(struct gfs2_inode *ip)
1114 {
1115 	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
1116 	struct gfs2_rgrpd *rgd;
1117 	struct gfs2_holder gh;
1118 	int error;
1119 
1120 	if (gfs2_get_inode_blocks(&ip->i_inode) != 1) {
1121 		gfs2_consist_inode(ip);
1122 		return -EIO;
1123 	}
1124 
1125 	error = gfs2_rindex_update(sdp);
1126 	if (error)
1127 		return error;
1128 
1129 	error = gfs2_quota_hold(ip, NO_UID_QUOTA_CHANGE, NO_GID_QUOTA_CHANGE);
1130 	if (error)
1131 		return error;
1132 
1133 	rgd = gfs2_blk2rgrpd(sdp, ip->i_no_addr, 1);
1134 	if (!rgd) {
1135 		gfs2_consist_inode(ip);
1136 		error = -EIO;
1137 		goto out_qs;
1138 	}
1139 
1140 	error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_EXCLUSIVE,
1141 				   LM_FLAG_NODE_SCOPE, &gh);
1142 	if (error)
1143 		goto out_qs;
1144 
1145 	error = gfs2_trans_begin(sdp, RES_RG_BIT + RES_STATFS + RES_QUOTA,
1146 				 sdp->sd_jdesc->jd_blocks);
1147 	if (error)
1148 		goto out_rg_gunlock;
1149 
1150 	gfs2_free_di(rgd, ip);
1151 
1152 	gfs2_final_release_pages(ip);
1153 
1154 	gfs2_trans_end(sdp);
1155 
1156 out_rg_gunlock:
1157 	gfs2_glock_dq_uninit(&gh);
1158 out_qs:
1159 	gfs2_quota_unhold(ip);
1160 	return error;
1161 }
1162 
1163 /**
1164  * gfs2_glock_put_eventually
1165  * @gl:	The glock to put
1166  *
1167  * When under memory pressure, trigger a deferred glock put to make sure we
1168  * won't call into DLM and deadlock.  Otherwise, put the glock directly.
1169  */
1170 
1171 static void gfs2_glock_put_eventually(struct gfs2_glock *gl)
1172 {
1173 	if (current->flags & PF_MEMALLOC)
1174 		gfs2_glock_queue_put(gl);
1175 	else
1176 		gfs2_glock_put(gl);
1177 }
1178 
1179 static bool gfs2_upgrade_iopen_glock(struct inode *inode)
1180 {
1181 	struct gfs2_inode *ip = GFS2_I(inode);
1182 	struct gfs2_sbd *sdp = GFS2_SB(inode);
1183 	struct gfs2_holder *gh = &ip->i_iopen_gh;
1184 	long timeout = 5 * HZ;
1185 	int error;
1186 
1187 	gh->gh_flags |= GL_NOCACHE;
1188 	gfs2_glock_dq_wait(gh);
1189 
1190 	/*
1191 	 * If there are no other lock holders, we will immediately get
1192 	 * exclusive access to the iopen glock here.
1193 	 *
1194 	 * Otherwise, the other nodes holding the lock will be notified about
1195 	 * our locking request.  If they do not have the inode open, they are
1196 	 * expected to evict the cached inode and release the lock, allowing us
1197 	 * to proceed.
1198 	 *
1199 	 * Otherwise, if they cannot evict the inode, they are expected to poke
1200 	 * the inode glock (note: not the iopen glock).  We will notice that
1201 	 * and stop waiting for the iopen glock immediately.  The other node(s)
1202 	 * are then expected to take care of deleting the inode when they no
1203 	 * longer use it.
1204 	 *
1205 	 * As a last resort, if another node keeps holding the iopen glock
1206 	 * without showing any activity on the inode glock, we will eventually
1207 	 * time out and fail the iopen glock upgrade.
1208 	 *
1209 	 * Note that we're passing the LM_FLAG_TRY_1CB flag to the first
1210 	 * locking request as an optimization to notify lock holders as soon as
1211 	 * possible.  Without that flag, they'd be notified implicitly by the
1212 	 * second locking request.
1213 	 */
1214 
1215 	gfs2_holder_reinit(LM_ST_EXCLUSIVE, LM_FLAG_TRY_1CB | GL_NOCACHE, gh);
1216 	error = gfs2_glock_nq(gh);
1217 	if (error != GLR_TRYFAILED)
1218 		return !error;
1219 
1220 	gfs2_holder_reinit(LM_ST_EXCLUSIVE, GL_ASYNC | GL_NOCACHE, gh);
1221 	error = gfs2_glock_nq(gh);
1222 	if (error)
1223 		return false;
1224 
1225 	timeout = wait_event_interruptible_timeout(sdp->sd_async_glock_wait,
1226 		!test_bit(HIF_WAIT, &gh->gh_iflags) ||
1227 		test_bit(GLF_DEMOTE, &ip->i_gl->gl_flags),
1228 		timeout);
1229 	if (!test_bit(HIF_HOLDER, &gh->gh_iflags)) {
1230 		gfs2_glock_dq(gh);
1231 		return false;
1232 	}
1233 	return gfs2_glock_holder_ready(gh) == 0;
1234 }
1235 
1236 /**
1237  * evict_should_delete - determine whether the inode is eligible for deletion
1238  * @inode: The inode to evict
1239  * @gh: The glock holder structure
1240  *
1241  * This function determines whether the evicted inode is eligible to be deleted
1242  * and locks the inode glock.
1243  *
1244  * Returns: the fate of the dinode
1245  */
1246 static enum dinode_demise evict_should_delete(struct inode *inode,
1247 					      struct gfs2_holder *gh)
1248 {
1249 	struct gfs2_inode *ip = GFS2_I(inode);
1250 	struct super_block *sb = inode->i_sb;
1251 	struct gfs2_sbd *sdp = sb->s_fs_info;
1252 	int ret;
1253 
1254 	if (unlikely(test_bit(GIF_ALLOC_FAILED, &ip->i_flags)))
1255 		goto should_delete;
1256 
1257 	if (test_bit(GIF_DEFERRED_DELETE, &ip->i_flags))
1258 		return SHOULD_DEFER_EVICTION;
1259 
1260 	/* Deletes should never happen under memory pressure anymore.  */
1261 	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
1262 		return SHOULD_DEFER_EVICTION;
1263 
1264 	/* Must not read inode block until block type has been verified */
1265 	ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_SKIP, gh);
1266 	if (unlikely(ret)) {
1267 		glock_clear_object(ip->i_iopen_gh.gh_gl, ip);
1268 		ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
1269 		gfs2_glock_dq_uninit(&ip->i_iopen_gh);
1270 		return SHOULD_DEFER_EVICTION;
1271 	}
1272 
1273 	if (gfs2_inode_already_deleted(ip->i_gl, ip->i_no_formal_ino))
1274 		return SHOULD_NOT_DELETE_DINODE;
1275 	ret = gfs2_check_blk_type(sdp, ip->i_no_addr, GFS2_BLKST_UNLINKED);
1276 	if (ret)
1277 		return SHOULD_NOT_DELETE_DINODE;
1278 
1279 	ret = gfs2_instantiate(gh);
1280 	if (ret)
1281 		return SHOULD_NOT_DELETE_DINODE;
1282 
1283 	/*
1284 	 * The inode may have been recreated in the meantime.
1285 	 */
1286 	if (inode->i_nlink)
1287 		return SHOULD_NOT_DELETE_DINODE;
1288 
1289 should_delete:
1290 	if (gfs2_holder_initialized(&ip->i_iopen_gh) &&
1291 	    test_bit(HIF_HOLDER, &ip->i_iopen_gh.gh_iflags)) {
1292 		if (!gfs2_upgrade_iopen_glock(inode)) {
1293 			gfs2_holder_uninit(&ip->i_iopen_gh);
1294 			return SHOULD_NOT_DELETE_DINODE;
1295 		}
1296 	}
1297 	return SHOULD_DELETE_DINODE;
1298 }
1299 
1300 /**
1301  * evict_unlinked_inode - delete the pieces of an unlinked evicted inode
1302  * @inode: The inode to evict
1303  */
1304 static int evict_unlinked_inode(struct inode *inode)
1305 {
1306 	struct gfs2_inode *ip = GFS2_I(inode);
1307 	int ret;
1308 
1309 	if (S_ISDIR(inode->i_mode) &&
1310 	    (ip->i_diskflags & GFS2_DIF_EXHASH)) {
1311 		ret = gfs2_dir_exhash_dealloc(ip);
1312 		if (ret)
1313 			goto out;
1314 	}
1315 
1316 	if (ip->i_eattr) {
1317 		ret = gfs2_ea_dealloc(ip);
1318 		if (ret)
1319 			goto out;
1320 	}
1321 
1322 	if (!gfs2_is_stuffed(ip)) {
1323 		ret = gfs2_file_dealloc(ip);
1324 		if (ret)
1325 			goto out;
1326 	}
1327 
1328 	if (ip->i_gl)
1329 		gfs2_inode_remember_delete(ip->i_gl, ip->i_no_formal_ino);
1330 
1331 	/*
1332 	 * As soon as we clear the bitmap for the dinode, gfs2_create_inode()
1333 	 * can get called to recreate it, or even gfs2_inode_lookup() if the
1334 	 * inode was recreated on another node in the meantime.
1335 	 *
1336 	 * However, inserting the new inode into the inode hash table will not
1337 	 * succeed until the old inode is removed, and that only happens after
1338 	 * ->evict_inode() returns.  The new inode is attached to its inode and
1339 	 *  iopen glocks after inserting it into the inode hash table, so at
1340 	 *  that point we can be sure that both glocks are unused.
1341 	 */
1342 
1343 	ret = gfs2_dinode_dealloc(ip);
1344 out:
1345 	return ret;
1346 }
1347 
1348 /*
1349  * evict_linked_inode - evict an inode whose dinode has not been unlinked
1350  * @inode: The inode to evict
1351  */
1352 static int evict_linked_inode(struct inode *inode)
1353 {
1354 	struct super_block *sb = inode->i_sb;
1355 	struct gfs2_sbd *sdp = sb->s_fs_info;
1356 	struct gfs2_inode *ip = GFS2_I(inode);
1357 	struct address_space *metamapping;
1358 	int ret;
1359 
1360 	gfs2_log_flush(sdp, ip->i_gl, GFS2_LOG_HEAD_FLUSH_NORMAL |
1361 		       GFS2_LFC_EVICT_INODE);
1362 	metamapping = gfs2_glock2aspace(ip->i_gl);
1363 	if (test_bit(GLF_DIRTY, &ip->i_gl->gl_flags)) {
1364 		filemap_fdatawrite(metamapping);
1365 		filemap_fdatawait(metamapping);
1366 	}
1367 	write_inode_now(inode, 1);
1368 	gfs2_ail_flush(ip->i_gl, 0);
1369 
1370 	ret = gfs2_trans_begin(sdp, 0, sdp->sd_jdesc->jd_blocks);
1371 	if (ret)
1372 		return ret;
1373 
1374 	/* Needs to be done before glock release & also in a transaction */
1375 	truncate_inode_pages(&inode->i_data, 0);
1376 	truncate_inode_pages(metamapping, 0);
1377 	gfs2_trans_end(sdp);
1378 	return 0;
1379 }
1380 
1381 /**
1382  * gfs2_evict_inode - Remove an inode from cache
1383  * @inode: The inode to evict
1384  *
1385  * There are three cases to consider:
1386  * 1. i_nlink == 0, we are final opener (and must deallocate)
1387  * 2. i_nlink == 0, we are not the final opener (and cannot deallocate)
1388  * 3. i_nlink > 0
1389  *
1390  * If the fs is read only, then we have to treat all cases as per #3
1391  * since we are unable to do any deallocation. The inode will be
1392  * deallocated by the next read/write node to attempt an allocation
1393  * in the same resource group
1394  *
1395  * We have to (at the moment) hold the inodes main lock to cover
1396  * the gap between unlocking the shared lock on the iopen lock and
1397  * taking the exclusive lock. I'd rather do a shared -> exclusive
1398  * conversion on the iopen lock, but we can change that later. This
1399  * is safe, just less efficient.
1400  */
1401 
1402 static void gfs2_evict_inode(struct inode *inode)
1403 {
1404 	struct super_block *sb = inode->i_sb;
1405 	struct gfs2_sbd *sdp = sb->s_fs_info;
1406 	struct gfs2_inode *ip = GFS2_I(inode);
1407 	struct gfs2_holder gh;
1408 	int ret;
1409 
1410 	if (inode->i_nlink || sb_rdonly(sb) || !ip->i_no_addr)
1411 		goto out;
1412 
1413 	gfs2_holder_mark_uninitialized(&gh);
1414 	ret = evict_should_delete(inode, &gh);
1415 	if (ret == SHOULD_DEFER_EVICTION)
1416 		goto out;
1417 	if (ret == SHOULD_DELETE_DINODE)
1418 		ret = evict_unlinked_inode(inode);
1419 	else
1420 		ret = evict_linked_inode(inode);
1421 
1422 	if (gfs2_rs_active(&ip->i_res))
1423 		gfs2_rs_deltree(&ip->i_res);
1424 
1425 	if (gfs2_holder_initialized(&gh))
1426 		gfs2_glock_dq_uninit(&gh);
1427 	if (ret && ret != GLR_TRYFAILED && ret != -EROFS)
1428 		fs_warn(sdp, "gfs2_evict_inode: %d\n", ret);
1429 out:
1430 	truncate_inode_pages_final(&inode->i_data);
1431 	if (ip->i_qadata)
1432 		gfs2_assert_warn(sdp, ip->i_qadata->qa_ref == 0);
1433 	gfs2_rs_deltree(&ip->i_res);
1434 	gfs2_ordered_del_inode(ip);
1435 	clear_inode(inode);
1436 	gfs2_dir_hash_inval(ip);
1437 	if (gfs2_holder_initialized(&ip->i_iopen_gh)) {
1438 		struct gfs2_glock *gl = ip->i_iopen_gh.gh_gl;
1439 
1440 		glock_clear_object(gl, ip);
1441 		gfs2_glock_hold(gl);
1442 		ip->i_iopen_gh.gh_flags |= GL_NOCACHE;
1443 		gfs2_glock_dq_uninit(&ip->i_iopen_gh);
1444 		gfs2_glock_put_eventually(gl);
1445 	}
1446 	if (ip->i_gl) {
1447 		glock_clear_object(ip->i_gl, ip);
1448 		wait_on_bit_io(&ip->i_flags, GIF_GLOP_PENDING, TASK_UNINTERRUPTIBLE);
1449 		gfs2_glock_add_to_lru(ip->i_gl);
1450 		gfs2_glock_put_eventually(ip->i_gl);
1451 		ip->i_gl = NULL;
1452 	}
1453 }
1454 
1455 static struct inode *gfs2_alloc_inode(struct super_block *sb)
1456 {
1457 	struct gfs2_inode *ip;
1458 
1459 	ip = alloc_inode_sb(sb, gfs2_inode_cachep, GFP_KERNEL);
1460 	if (!ip)
1461 		return NULL;
1462 	ip->i_no_addr = 0;
1463 	ip->i_flags = 0;
1464 	ip->i_gl = NULL;
1465 	gfs2_holder_mark_uninitialized(&ip->i_iopen_gh);
1466 	memset(&ip->i_res, 0, sizeof(ip->i_res));
1467 	RB_CLEAR_NODE(&ip->i_res.rs_node);
1468 	ip->i_rahead = 0;
1469 	return &ip->i_inode;
1470 }
1471 
1472 static void gfs2_free_inode(struct inode *inode)
1473 {
1474 	kmem_cache_free(gfs2_inode_cachep, GFS2_I(inode));
1475 }
1476 
1477 extern void free_local_statfs_inodes(struct gfs2_sbd *sdp)
1478 {
1479 	struct local_statfs_inode *lsi, *safe;
1480 
1481 	/* Run through the statfs inodes list to iput and free memory */
1482 	list_for_each_entry_safe(lsi, safe, &sdp->sd_sc_inodes_list, si_list) {
1483 		if (lsi->si_jid == sdp->sd_jdesc->jd_jid)
1484 			sdp->sd_sc_inode = NULL; /* belongs to this node */
1485 		if (lsi->si_sc_inode)
1486 			iput(lsi->si_sc_inode);
1487 		list_del(&lsi->si_list);
1488 		kfree(lsi);
1489 	}
1490 }
1491 
1492 extern struct inode *find_local_statfs_inode(struct gfs2_sbd *sdp,
1493 					     unsigned int index)
1494 {
1495 	struct local_statfs_inode *lsi;
1496 
1497 	/* Return the local (per node) statfs inode in the
1498 	 * sdp->sd_sc_inodes_list corresponding to the 'index'. */
1499 	list_for_each_entry(lsi, &sdp->sd_sc_inodes_list, si_list) {
1500 		if (lsi->si_jid == index)
1501 			return lsi->si_sc_inode;
1502 	}
1503 	return NULL;
1504 }
1505 
1506 const struct super_operations gfs2_super_ops = {
1507 	.alloc_inode		= gfs2_alloc_inode,
1508 	.free_inode		= gfs2_free_inode,
1509 	.write_inode		= gfs2_write_inode,
1510 	.dirty_inode		= gfs2_dirty_inode,
1511 	.evict_inode		= gfs2_evict_inode,
1512 	.put_super		= gfs2_put_super,
1513 	.sync_fs		= gfs2_sync_fs,
1514 	.freeze_super		= gfs2_freeze,
1515 	.thaw_super		= gfs2_unfreeze,
1516 	.statfs			= gfs2_statfs,
1517 	.drop_inode		= gfs2_drop_inode,
1518 	.show_options		= gfs2_show_options,
1519 };
1520 
1521