xref: /linux/fs/xfs/libxfs/xfs_ag.c (revision a095686a2383526d7315197e2419d84ee8470217)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
4  * Copyright (c) 2018 Red Hat, Inc.
5  * All rights reserved.
6  */
7 
8 #include "xfs.h"
9 #include "xfs_fs.h"
10 #include "xfs_shared.h"
11 #include "xfs_format.h"
12 #include "xfs_trans_resv.h"
13 #include "xfs_bit.h"
14 #include "xfs_sb.h"
15 #include "xfs_mount.h"
16 #include "xfs_btree.h"
17 #include "xfs_alloc_btree.h"
18 #include "xfs_rmap_btree.h"
19 #include "xfs_alloc.h"
20 #include "xfs_ialloc.h"
21 #include "xfs_rmap.h"
22 #include "xfs_ag.h"
23 #include "xfs_ag_resv.h"
24 #include "xfs_health.h"
25 #include "xfs_error.h"
26 #include "xfs_bmap.h"
27 #include "xfs_defer.h"
28 #include "xfs_log_format.h"
29 #include "xfs_trans.h"
30 #include "xfs_trace.h"
31 #include "xfs_inode.h"
32 #include "xfs_icache.h"
33 
34 
35 /*
36  * Passive reference counting access wrappers to the perag structures.  If the
37  * per-ag structure is to be freed, the freeing code is responsible for cleaning
38  * up objects with passive references before freeing the structure. This is
39  * things like cached buffers.
40  */
41 struct xfs_perag *
42 xfs_perag_get(
43 	struct xfs_mount	*mp,
44 	xfs_agnumber_t		agno)
45 {
46 	struct xfs_perag	*pag;
47 
48 	rcu_read_lock();
49 	pag = radix_tree_lookup(&mp->m_perag_tree, agno);
50 	if (pag) {
51 		trace_xfs_perag_get(pag, _RET_IP_);
52 		ASSERT(atomic_read(&pag->pag_ref) >= 0);
53 		atomic_inc(&pag->pag_ref);
54 	}
55 	rcu_read_unlock();
56 	return pag;
57 }
58 
59 /*
60  * search from @first to find the next perag with the given tag set.
61  */
62 struct xfs_perag *
63 xfs_perag_get_tag(
64 	struct xfs_mount	*mp,
65 	xfs_agnumber_t		first,
66 	unsigned int		tag)
67 {
68 	struct xfs_perag	*pag;
69 	int			found;
70 
71 	rcu_read_lock();
72 	found = radix_tree_gang_lookup_tag(&mp->m_perag_tree,
73 					(void **)&pag, first, 1, tag);
74 	if (found <= 0) {
75 		rcu_read_unlock();
76 		return NULL;
77 	}
78 	trace_xfs_perag_get_tag(pag, _RET_IP_);
79 	atomic_inc(&pag->pag_ref);
80 	rcu_read_unlock();
81 	return pag;
82 }
83 
84 /* Get a passive reference to the given perag. */
85 struct xfs_perag *
86 xfs_perag_hold(
87 	struct xfs_perag	*pag)
88 {
89 	ASSERT(atomic_read(&pag->pag_ref) > 0 ||
90 	       atomic_read(&pag->pag_active_ref) > 0);
91 
92 	trace_xfs_perag_hold(pag, _RET_IP_);
93 	atomic_inc(&pag->pag_ref);
94 	return pag;
95 }
96 
97 void
98 xfs_perag_put(
99 	struct xfs_perag	*pag)
100 {
101 	trace_xfs_perag_put(pag, _RET_IP_);
102 	ASSERT(atomic_read(&pag->pag_ref) > 0);
103 	atomic_dec(&pag->pag_ref);
104 }
105 
106 /*
107  * Active references for perag structures. This is for short term access to the
108  * per ag structures for walking trees or accessing state. If an AG is being
109  * shrunk or is offline, then this will fail to find that AG and return NULL
110  * instead.
111  */
112 struct xfs_perag *
113 xfs_perag_grab(
114 	struct xfs_mount	*mp,
115 	xfs_agnumber_t		agno)
116 {
117 	struct xfs_perag	*pag;
118 
119 	rcu_read_lock();
120 	pag = radix_tree_lookup(&mp->m_perag_tree, agno);
121 	if (pag) {
122 		trace_xfs_perag_grab(pag, _RET_IP_);
123 		if (!atomic_inc_not_zero(&pag->pag_active_ref))
124 			pag = NULL;
125 	}
126 	rcu_read_unlock();
127 	return pag;
128 }
129 
130 /*
131  * search from @first to find the next perag with the given tag set.
132  */
133 struct xfs_perag *
134 xfs_perag_grab_tag(
135 	struct xfs_mount	*mp,
136 	xfs_agnumber_t		first,
137 	int			tag)
138 {
139 	struct xfs_perag	*pag;
140 	int			found;
141 
142 	rcu_read_lock();
143 	found = radix_tree_gang_lookup_tag(&mp->m_perag_tree,
144 					(void **)&pag, first, 1, tag);
145 	if (found <= 0) {
146 		rcu_read_unlock();
147 		return NULL;
148 	}
149 	trace_xfs_perag_grab_tag(pag, _RET_IP_);
150 	if (!atomic_inc_not_zero(&pag->pag_active_ref))
151 		pag = NULL;
152 	rcu_read_unlock();
153 	return pag;
154 }
155 
156 void
157 xfs_perag_rele(
158 	struct xfs_perag	*pag)
159 {
160 	trace_xfs_perag_rele(pag, _RET_IP_);
161 	if (atomic_dec_and_test(&pag->pag_active_ref))
162 		wake_up(&pag->pag_active_wq);
163 }
164 
165 /*
166  * xfs_initialize_perag_data
167  *
168  * Read in each per-ag structure so we can count up the number of
169  * allocated inodes, free inodes and used filesystem blocks as this
170  * information is no longer persistent in the superblock. Once we have
171  * this information, write it into the in-core superblock structure.
172  */
173 int
174 xfs_initialize_perag_data(
175 	struct xfs_mount	*mp,
176 	xfs_agnumber_t		agcount)
177 {
178 	xfs_agnumber_t		index;
179 	struct xfs_perag	*pag;
180 	struct xfs_sb		*sbp = &mp->m_sb;
181 	uint64_t		ifree = 0;
182 	uint64_t		ialloc = 0;
183 	uint64_t		bfree = 0;
184 	uint64_t		bfreelst = 0;
185 	uint64_t		btree = 0;
186 	uint64_t		fdblocks;
187 	int			error = 0;
188 
189 	for (index = 0; index < agcount; index++) {
190 		/*
191 		 * Read the AGF and AGI buffers to populate the per-ag
192 		 * structures for us.
193 		 */
194 		pag = xfs_perag_get(mp, index);
195 		error = xfs_alloc_read_agf(pag, NULL, 0, NULL);
196 		if (!error)
197 			error = xfs_ialloc_read_agi(pag, NULL, NULL);
198 		if (error) {
199 			xfs_perag_put(pag);
200 			return error;
201 		}
202 
203 		ifree += pag->pagi_freecount;
204 		ialloc += pag->pagi_count;
205 		bfree += pag->pagf_freeblks;
206 		bfreelst += pag->pagf_flcount;
207 		btree += pag->pagf_btreeblks;
208 		xfs_perag_put(pag);
209 	}
210 	fdblocks = bfree + bfreelst + btree;
211 
212 	/*
213 	 * If the new summary counts are obviously incorrect, fail the
214 	 * mount operation because that implies the AGFs are also corrupt.
215 	 * Clear FS_COUNTERS so that we don't unmount with a dirty log, which
216 	 * will prevent xfs_repair from fixing anything.
217 	 */
218 	if (fdblocks > sbp->sb_dblocks || ifree > ialloc) {
219 		xfs_alert(mp, "AGF corruption. Please run xfs_repair.");
220 		xfs_fs_mark_sick(mp, XFS_SICK_FS_COUNTERS);
221 		error = -EFSCORRUPTED;
222 		goto out;
223 	}
224 
225 	/* Overwrite incore superblock counters with just-read data */
226 	spin_lock(&mp->m_sb_lock);
227 	sbp->sb_ifree = ifree;
228 	sbp->sb_icount = ialloc;
229 	sbp->sb_fdblocks = fdblocks;
230 	spin_unlock(&mp->m_sb_lock);
231 
232 	xfs_reinit_percpu_counters(mp);
233 out:
234 	xfs_fs_mark_healthy(mp, XFS_SICK_FS_COUNTERS);
235 	return error;
236 }
237 
238 STATIC void
239 __xfs_free_perag(
240 	struct rcu_head	*head)
241 {
242 	struct xfs_perag *pag = container_of(head, struct xfs_perag, rcu_head);
243 
244 	ASSERT(!delayed_work_pending(&pag->pag_blockgc_work));
245 	kfree(pag);
246 }
247 
248 /*
249  * Free up the per-ag resources associated with the mount structure.
250  */
251 void
252 xfs_free_perag(
253 	struct xfs_mount	*mp)
254 {
255 	struct xfs_perag	*pag;
256 	xfs_agnumber_t		agno;
257 
258 	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
259 		spin_lock(&mp->m_perag_lock);
260 		pag = radix_tree_delete(&mp->m_perag_tree, agno);
261 		spin_unlock(&mp->m_perag_lock);
262 		ASSERT(pag);
263 		XFS_IS_CORRUPT(pag->pag_mount, atomic_read(&pag->pag_ref) != 0);
264 		xfs_defer_drain_free(&pag->pag_intents_drain);
265 
266 		cancel_delayed_work_sync(&pag->pag_blockgc_work);
267 		xfs_buf_cache_destroy(&pag->pag_bcache);
268 
269 		/* drop the mount's active reference */
270 		xfs_perag_rele(pag);
271 		XFS_IS_CORRUPT(pag->pag_mount,
272 				atomic_read(&pag->pag_active_ref) != 0);
273 		call_rcu(&pag->rcu_head, __xfs_free_perag);
274 	}
275 }
276 
277 /* Find the size of the AG, in blocks. */
278 static xfs_agblock_t
279 __xfs_ag_block_count(
280 	struct xfs_mount	*mp,
281 	xfs_agnumber_t		agno,
282 	xfs_agnumber_t		agcount,
283 	xfs_rfsblock_t		dblocks)
284 {
285 	ASSERT(agno < agcount);
286 
287 	if (agno < agcount - 1)
288 		return mp->m_sb.sb_agblocks;
289 	return dblocks - (agno * mp->m_sb.sb_agblocks);
290 }
291 
292 xfs_agblock_t
293 xfs_ag_block_count(
294 	struct xfs_mount	*mp,
295 	xfs_agnumber_t		agno)
296 {
297 	return __xfs_ag_block_count(mp, agno, mp->m_sb.sb_agcount,
298 			mp->m_sb.sb_dblocks);
299 }
300 
301 /* Calculate the first and last possible inode number in an AG. */
302 static void
303 __xfs_agino_range(
304 	struct xfs_mount	*mp,
305 	xfs_agblock_t		eoag,
306 	xfs_agino_t		*first,
307 	xfs_agino_t		*last)
308 {
309 	xfs_agblock_t		bno;
310 
311 	/*
312 	 * Calculate the first inode, which will be in the first
313 	 * cluster-aligned block after the AGFL.
314 	 */
315 	bno = round_up(XFS_AGFL_BLOCK(mp) + 1, M_IGEO(mp)->cluster_align);
316 	*first = XFS_AGB_TO_AGINO(mp, bno);
317 
318 	/*
319 	 * Calculate the last inode, which will be at the end of the
320 	 * last (aligned) cluster that can be allocated in the AG.
321 	 */
322 	bno = round_down(eoag, M_IGEO(mp)->cluster_align);
323 	*last = XFS_AGB_TO_AGINO(mp, bno) - 1;
324 }
325 
326 void
327 xfs_agino_range(
328 	struct xfs_mount	*mp,
329 	xfs_agnumber_t		agno,
330 	xfs_agino_t		*first,
331 	xfs_agino_t		*last)
332 {
333 	return __xfs_agino_range(mp, xfs_ag_block_count(mp, agno), first, last);
334 }
335 
336 /*
337  * Free perag within the specified AG range, it is only used to free unused
338  * perags under the error handling path.
339  */
340 void
341 xfs_free_unused_perag_range(
342 	struct xfs_mount	*mp,
343 	xfs_agnumber_t		agstart,
344 	xfs_agnumber_t		agend)
345 {
346 	struct xfs_perag	*pag;
347 	xfs_agnumber_t		index;
348 
349 	for (index = agstart; index < agend; index++) {
350 		spin_lock(&mp->m_perag_lock);
351 		pag = radix_tree_delete(&mp->m_perag_tree, index);
352 		spin_unlock(&mp->m_perag_lock);
353 		if (!pag)
354 			break;
355 		xfs_buf_cache_destroy(&pag->pag_bcache);
356 		xfs_defer_drain_free(&pag->pag_intents_drain);
357 		kfree(pag);
358 	}
359 }
360 
361 int
362 xfs_initialize_perag(
363 	struct xfs_mount	*mp,
364 	xfs_agnumber_t		agcount,
365 	xfs_rfsblock_t		dblocks,
366 	xfs_agnumber_t		*maxagi)
367 {
368 	struct xfs_perag	*pag;
369 	xfs_agnumber_t		index;
370 	xfs_agnumber_t		first_initialised = NULLAGNUMBER;
371 	int			error;
372 
373 	/*
374 	 * Walk the current per-ag tree so we don't try to initialise AGs
375 	 * that already exist (growfs case). Allocate and insert all the
376 	 * AGs we don't find ready for initialisation.
377 	 */
378 	for (index = 0; index < agcount; index++) {
379 		pag = xfs_perag_get(mp, index);
380 		if (pag) {
381 			xfs_perag_put(pag);
382 			continue;
383 		}
384 
385 		pag = kzalloc(sizeof(*pag), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
386 		if (!pag) {
387 			error = -ENOMEM;
388 			goto out_unwind_new_pags;
389 		}
390 		pag->pag_agno = index;
391 		pag->pag_mount = mp;
392 
393 		error = radix_tree_preload(GFP_KERNEL | __GFP_RETRY_MAYFAIL);
394 		if (error)
395 			goto out_free_pag;
396 
397 		spin_lock(&mp->m_perag_lock);
398 		if (radix_tree_insert(&mp->m_perag_tree, index, pag)) {
399 			WARN_ON_ONCE(1);
400 			spin_unlock(&mp->m_perag_lock);
401 			radix_tree_preload_end();
402 			error = -EEXIST;
403 			goto out_free_pag;
404 		}
405 		spin_unlock(&mp->m_perag_lock);
406 		radix_tree_preload_end();
407 
408 #ifdef __KERNEL__
409 		/* Place kernel structure only init below this point. */
410 		spin_lock_init(&pag->pag_ici_lock);
411 		spin_lock_init(&pag->pagb_lock);
412 		spin_lock_init(&pag->pag_state_lock);
413 		INIT_DELAYED_WORK(&pag->pag_blockgc_work, xfs_blockgc_worker);
414 		INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
415 		xfs_defer_drain_init(&pag->pag_intents_drain);
416 		init_waitqueue_head(&pag->pagb_wait);
417 		init_waitqueue_head(&pag->pag_active_wq);
418 		pag->pagb_count = 0;
419 		pag->pagb_tree = RB_ROOT;
420 #endif /* __KERNEL__ */
421 
422 		error = xfs_buf_cache_init(&pag->pag_bcache);
423 		if (error)
424 			goto out_remove_pag;
425 
426 		/* Active ref owned by mount indicates AG is online. */
427 		atomic_set(&pag->pag_active_ref, 1);
428 
429 		/* first new pag is fully initialized */
430 		if (first_initialised == NULLAGNUMBER)
431 			first_initialised = index;
432 
433 		/*
434 		 * Pre-calculated geometry
435 		 */
436 		pag->block_count = __xfs_ag_block_count(mp, index, agcount,
437 				dblocks);
438 		pag->min_block = XFS_AGFL_BLOCK(mp);
439 		__xfs_agino_range(mp, pag->block_count, &pag->agino_min,
440 				&pag->agino_max);
441 	}
442 
443 	index = xfs_set_inode_alloc(mp, agcount);
444 
445 	if (maxagi)
446 		*maxagi = index;
447 
448 	mp->m_ag_prealloc_blocks = xfs_prealloc_blocks(mp);
449 	return 0;
450 
451 out_remove_pag:
452 	xfs_defer_drain_free(&pag->pag_intents_drain);
453 	spin_lock(&mp->m_perag_lock);
454 	radix_tree_delete(&mp->m_perag_tree, index);
455 	spin_unlock(&mp->m_perag_lock);
456 out_free_pag:
457 	kfree(pag);
458 out_unwind_new_pags:
459 	/* unwind any prior newly initialized pags */
460 	xfs_free_unused_perag_range(mp, first_initialised, agcount);
461 	return error;
462 }
463 
464 static int
465 xfs_get_aghdr_buf(
466 	struct xfs_mount	*mp,
467 	xfs_daddr_t		blkno,
468 	size_t			numblks,
469 	struct xfs_buf		**bpp,
470 	const struct xfs_buf_ops *ops)
471 {
472 	struct xfs_buf		*bp;
473 	int			error;
474 
475 	error = xfs_buf_get_uncached(mp->m_ddev_targp, numblks, 0, &bp);
476 	if (error)
477 		return error;
478 
479 	bp->b_maps[0].bm_bn = blkno;
480 	bp->b_ops = ops;
481 
482 	*bpp = bp;
483 	return 0;
484 }
485 
486 /*
487  * Generic btree root block init function
488  */
489 static void
490 xfs_btroot_init(
491 	struct xfs_mount	*mp,
492 	struct xfs_buf		*bp,
493 	struct aghdr_init_data	*id)
494 {
495 	xfs_btree_init_buf(mp, bp, id->bc_ops, 0, 0, id->agno);
496 }
497 
498 /* Finish initializing a free space btree. */
499 static void
500 xfs_freesp_init_recs(
501 	struct xfs_mount	*mp,
502 	struct xfs_buf		*bp,
503 	struct aghdr_init_data	*id)
504 {
505 	struct xfs_alloc_rec	*arec;
506 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
507 
508 	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
509 	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
510 
511 	if (xfs_ag_contains_log(mp, id->agno)) {
512 		struct xfs_alloc_rec	*nrec;
513 		xfs_agblock_t		start = XFS_FSB_TO_AGBNO(mp,
514 							mp->m_sb.sb_logstart);
515 
516 		ASSERT(start >= mp->m_ag_prealloc_blocks);
517 		if (start != mp->m_ag_prealloc_blocks) {
518 			/*
519 			 * Modify first record to pad stripe align of log and
520 			 * bump the record count.
521 			 */
522 			arec->ar_blockcount = cpu_to_be32(start -
523 						mp->m_ag_prealloc_blocks);
524 			be16_add_cpu(&block->bb_numrecs, 1);
525 			nrec = arec + 1;
526 
527 			/*
528 			 * Insert second record at start of internal log
529 			 * which then gets trimmed.
530 			 */
531 			nrec->ar_startblock = cpu_to_be32(
532 					be32_to_cpu(arec->ar_startblock) +
533 					be32_to_cpu(arec->ar_blockcount));
534 			arec = nrec;
535 		}
536 		/*
537 		 * Change record start to after the internal log
538 		 */
539 		be32_add_cpu(&arec->ar_startblock, mp->m_sb.sb_logblocks);
540 	}
541 
542 	/*
543 	 * Calculate the block count of this record; if it is nonzero,
544 	 * increment the record count.
545 	 */
546 	arec->ar_blockcount = cpu_to_be32(id->agsize -
547 					  be32_to_cpu(arec->ar_startblock));
548 	if (arec->ar_blockcount)
549 		be16_add_cpu(&block->bb_numrecs, 1);
550 }
551 
552 /*
553  * bnobt/cntbt btree root block init functions
554  */
555 static void
556 xfs_bnoroot_init(
557 	struct xfs_mount	*mp,
558 	struct xfs_buf		*bp,
559 	struct aghdr_init_data	*id)
560 {
561 	xfs_btree_init_buf(mp, bp, id->bc_ops, 0, 0, id->agno);
562 	xfs_freesp_init_recs(mp, bp, id);
563 }
564 
565 /*
566  * Reverse map root block init
567  */
568 static void
569 xfs_rmaproot_init(
570 	struct xfs_mount	*mp,
571 	struct xfs_buf		*bp,
572 	struct aghdr_init_data	*id)
573 {
574 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
575 	struct xfs_rmap_rec	*rrec;
576 
577 	xfs_btree_init_buf(mp, bp, id->bc_ops, 0, 4, id->agno);
578 
579 	/*
580 	 * mark the AG header regions as static metadata The BNO
581 	 * btree block is the first block after the headers, so
582 	 * it's location defines the size of region the static
583 	 * metadata consumes.
584 	 *
585 	 * Note: unlike mkfs, we never have to account for log
586 	 * space when growing the data regions
587 	 */
588 	rrec = XFS_RMAP_REC_ADDR(block, 1);
589 	rrec->rm_startblock = 0;
590 	rrec->rm_blockcount = cpu_to_be32(XFS_BNO_BLOCK(mp));
591 	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_FS);
592 	rrec->rm_offset = 0;
593 
594 	/* account freespace btree root blocks */
595 	rrec = XFS_RMAP_REC_ADDR(block, 2);
596 	rrec->rm_startblock = cpu_to_be32(XFS_BNO_BLOCK(mp));
597 	rrec->rm_blockcount = cpu_to_be32(2);
598 	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
599 	rrec->rm_offset = 0;
600 
601 	/* account inode btree root blocks */
602 	rrec = XFS_RMAP_REC_ADDR(block, 3);
603 	rrec->rm_startblock = cpu_to_be32(XFS_IBT_BLOCK(mp));
604 	rrec->rm_blockcount = cpu_to_be32(XFS_RMAP_BLOCK(mp) -
605 					  XFS_IBT_BLOCK(mp));
606 	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_INOBT);
607 	rrec->rm_offset = 0;
608 
609 	/* account for rmap btree root */
610 	rrec = XFS_RMAP_REC_ADDR(block, 4);
611 	rrec->rm_startblock = cpu_to_be32(XFS_RMAP_BLOCK(mp));
612 	rrec->rm_blockcount = cpu_to_be32(1);
613 	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
614 	rrec->rm_offset = 0;
615 
616 	/* account for refc btree root */
617 	if (xfs_has_reflink(mp)) {
618 		rrec = XFS_RMAP_REC_ADDR(block, 5);
619 		rrec->rm_startblock = cpu_to_be32(xfs_refc_block(mp));
620 		rrec->rm_blockcount = cpu_to_be32(1);
621 		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_REFC);
622 		rrec->rm_offset = 0;
623 		be16_add_cpu(&block->bb_numrecs, 1);
624 	}
625 
626 	/* account for the log space */
627 	if (xfs_ag_contains_log(mp, id->agno)) {
628 		rrec = XFS_RMAP_REC_ADDR(block,
629 				be16_to_cpu(block->bb_numrecs) + 1);
630 		rrec->rm_startblock = cpu_to_be32(
631 				XFS_FSB_TO_AGBNO(mp, mp->m_sb.sb_logstart));
632 		rrec->rm_blockcount = cpu_to_be32(mp->m_sb.sb_logblocks);
633 		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_LOG);
634 		rrec->rm_offset = 0;
635 		be16_add_cpu(&block->bb_numrecs, 1);
636 	}
637 }
638 
639 /*
640  * Initialise new secondary superblocks with the pre-grow geometry, but mark
641  * them as "in progress" so we know they haven't yet been activated. This will
642  * get cleared when the update with the new geometry information is done after
643  * changes to the primary are committed. This isn't strictly necessary, but we
644  * get it for free with the delayed buffer write lists and it means we can tell
645  * if a grow operation didn't complete properly after the fact.
646  */
647 static void
648 xfs_sbblock_init(
649 	struct xfs_mount	*mp,
650 	struct xfs_buf		*bp,
651 	struct aghdr_init_data	*id)
652 {
653 	struct xfs_dsb		*dsb = bp->b_addr;
654 
655 	xfs_sb_to_disk(dsb, &mp->m_sb);
656 	dsb->sb_inprogress = 1;
657 }
658 
659 static void
660 xfs_agfblock_init(
661 	struct xfs_mount	*mp,
662 	struct xfs_buf		*bp,
663 	struct aghdr_init_data	*id)
664 {
665 	struct xfs_agf		*agf = bp->b_addr;
666 	xfs_extlen_t		tmpsize;
667 
668 	agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
669 	agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
670 	agf->agf_seqno = cpu_to_be32(id->agno);
671 	agf->agf_length = cpu_to_be32(id->agsize);
672 	agf->agf_bno_root = cpu_to_be32(XFS_BNO_BLOCK(mp));
673 	agf->agf_cnt_root = cpu_to_be32(XFS_CNT_BLOCK(mp));
674 	agf->agf_bno_level = cpu_to_be32(1);
675 	agf->agf_cnt_level = cpu_to_be32(1);
676 	if (xfs_has_rmapbt(mp)) {
677 		agf->agf_rmap_root = cpu_to_be32(XFS_RMAP_BLOCK(mp));
678 		agf->agf_rmap_level = cpu_to_be32(1);
679 		agf->agf_rmap_blocks = cpu_to_be32(1);
680 	}
681 
682 	agf->agf_flfirst = cpu_to_be32(1);
683 	agf->agf_fllast = 0;
684 	agf->agf_flcount = 0;
685 	tmpsize = id->agsize - mp->m_ag_prealloc_blocks;
686 	agf->agf_freeblks = cpu_to_be32(tmpsize);
687 	agf->agf_longest = cpu_to_be32(tmpsize);
688 	if (xfs_has_crc(mp))
689 		uuid_copy(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid);
690 	if (xfs_has_reflink(mp)) {
691 		agf->agf_refcount_root = cpu_to_be32(
692 				xfs_refc_block(mp));
693 		agf->agf_refcount_level = cpu_to_be32(1);
694 		agf->agf_refcount_blocks = cpu_to_be32(1);
695 	}
696 
697 	if (xfs_ag_contains_log(mp, id->agno)) {
698 		int64_t	logblocks = mp->m_sb.sb_logblocks;
699 
700 		be32_add_cpu(&agf->agf_freeblks, -logblocks);
701 		agf->agf_longest = cpu_to_be32(id->agsize -
702 			XFS_FSB_TO_AGBNO(mp, mp->m_sb.sb_logstart) - logblocks);
703 	}
704 }
705 
706 static void
707 xfs_agflblock_init(
708 	struct xfs_mount	*mp,
709 	struct xfs_buf		*bp,
710 	struct aghdr_init_data	*id)
711 {
712 	struct xfs_agfl		*agfl = XFS_BUF_TO_AGFL(bp);
713 	__be32			*agfl_bno;
714 	int			bucket;
715 
716 	if (xfs_has_crc(mp)) {
717 		agfl->agfl_magicnum = cpu_to_be32(XFS_AGFL_MAGIC);
718 		agfl->agfl_seqno = cpu_to_be32(id->agno);
719 		uuid_copy(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid);
720 	}
721 
722 	agfl_bno = xfs_buf_to_agfl_bno(bp);
723 	for (bucket = 0; bucket < xfs_agfl_size(mp); bucket++)
724 		agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK);
725 }
726 
727 static void
728 xfs_agiblock_init(
729 	struct xfs_mount	*mp,
730 	struct xfs_buf		*bp,
731 	struct aghdr_init_data	*id)
732 {
733 	struct xfs_agi		*agi = bp->b_addr;
734 	int			bucket;
735 
736 	agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
737 	agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
738 	agi->agi_seqno = cpu_to_be32(id->agno);
739 	agi->agi_length = cpu_to_be32(id->agsize);
740 	agi->agi_count = 0;
741 	agi->agi_root = cpu_to_be32(XFS_IBT_BLOCK(mp));
742 	agi->agi_level = cpu_to_be32(1);
743 	agi->agi_freecount = 0;
744 	agi->agi_newino = cpu_to_be32(NULLAGINO);
745 	agi->agi_dirino = cpu_to_be32(NULLAGINO);
746 	if (xfs_has_crc(mp))
747 		uuid_copy(&agi->agi_uuid, &mp->m_sb.sb_meta_uuid);
748 	if (xfs_has_finobt(mp)) {
749 		agi->agi_free_root = cpu_to_be32(XFS_FIBT_BLOCK(mp));
750 		agi->agi_free_level = cpu_to_be32(1);
751 	}
752 	for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
753 		agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
754 	if (xfs_has_inobtcounts(mp)) {
755 		agi->agi_iblocks = cpu_to_be32(1);
756 		if (xfs_has_finobt(mp))
757 			agi->agi_fblocks = cpu_to_be32(1);
758 	}
759 }
760 
761 typedef void (*aghdr_init_work_f)(struct xfs_mount *mp, struct xfs_buf *bp,
762 				  struct aghdr_init_data *id);
763 static int
764 xfs_ag_init_hdr(
765 	struct xfs_mount	*mp,
766 	struct aghdr_init_data	*id,
767 	aghdr_init_work_f	work,
768 	const struct xfs_buf_ops *ops)
769 {
770 	struct xfs_buf		*bp;
771 	int			error;
772 
773 	error = xfs_get_aghdr_buf(mp, id->daddr, id->numblks, &bp, ops);
774 	if (error)
775 		return error;
776 
777 	(*work)(mp, bp, id);
778 
779 	xfs_buf_delwri_queue(bp, &id->buffer_list);
780 	xfs_buf_relse(bp);
781 	return 0;
782 }
783 
784 struct xfs_aghdr_grow_data {
785 	xfs_daddr_t		daddr;
786 	size_t			numblks;
787 	const struct xfs_buf_ops *ops;
788 	aghdr_init_work_f	work;
789 	const struct xfs_btree_ops *bc_ops;
790 	bool			need_init;
791 };
792 
793 /*
794  * Prepare new AG headers to be written to disk. We use uncached buffers here,
795  * as it is assumed these new AG headers are currently beyond the currently
796  * valid filesystem address space. Using cached buffers would trip over EOFS
797  * corruption detection alogrithms in the buffer cache lookup routines.
798  *
799  * This is a non-transactional function, but the prepared buffers are added to a
800  * delayed write buffer list supplied by the caller so they can submit them to
801  * disk and wait on them as required.
802  */
803 int
804 xfs_ag_init_headers(
805 	struct xfs_mount	*mp,
806 	struct aghdr_init_data	*id)
807 
808 {
809 	struct xfs_aghdr_grow_data aghdr_data[] = {
810 	{ /* SB */
811 		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_SB_DADDR),
812 		.numblks = XFS_FSS_TO_BB(mp, 1),
813 		.ops = &xfs_sb_buf_ops,
814 		.work = &xfs_sbblock_init,
815 		.need_init = true
816 	},
817 	{ /* AGF */
818 		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGF_DADDR(mp)),
819 		.numblks = XFS_FSS_TO_BB(mp, 1),
820 		.ops = &xfs_agf_buf_ops,
821 		.work = &xfs_agfblock_init,
822 		.need_init = true
823 	},
824 	{ /* AGFL */
825 		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGFL_DADDR(mp)),
826 		.numblks = XFS_FSS_TO_BB(mp, 1),
827 		.ops = &xfs_agfl_buf_ops,
828 		.work = &xfs_agflblock_init,
829 		.need_init = true
830 	},
831 	{ /* AGI */
832 		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGI_DADDR(mp)),
833 		.numblks = XFS_FSS_TO_BB(mp, 1),
834 		.ops = &xfs_agi_buf_ops,
835 		.work = &xfs_agiblock_init,
836 		.need_init = true
837 	},
838 	{ /* BNO root block */
839 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_BNO_BLOCK(mp)),
840 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
841 		.ops = &xfs_bnobt_buf_ops,
842 		.work = &xfs_bnoroot_init,
843 		.bc_ops = &xfs_bnobt_ops,
844 		.need_init = true
845 	},
846 	{ /* CNT root block */
847 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_CNT_BLOCK(mp)),
848 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
849 		.ops = &xfs_cntbt_buf_ops,
850 		.work = &xfs_bnoroot_init,
851 		.bc_ops = &xfs_cntbt_ops,
852 		.need_init = true
853 	},
854 	{ /* INO root block */
855 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_IBT_BLOCK(mp)),
856 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
857 		.ops = &xfs_inobt_buf_ops,
858 		.work = &xfs_btroot_init,
859 		.bc_ops = &xfs_inobt_ops,
860 		.need_init = true
861 	},
862 	{ /* FINO root block */
863 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_FIBT_BLOCK(mp)),
864 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
865 		.ops = &xfs_finobt_buf_ops,
866 		.work = &xfs_btroot_init,
867 		.bc_ops = &xfs_finobt_ops,
868 		.need_init =  xfs_has_finobt(mp)
869 	},
870 	{ /* RMAP root block */
871 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_RMAP_BLOCK(mp)),
872 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
873 		.ops = &xfs_rmapbt_buf_ops,
874 		.work = &xfs_rmaproot_init,
875 		.bc_ops = &xfs_rmapbt_ops,
876 		.need_init = xfs_has_rmapbt(mp)
877 	},
878 	{ /* REFC root block */
879 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, xfs_refc_block(mp)),
880 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
881 		.ops = &xfs_refcountbt_buf_ops,
882 		.work = &xfs_btroot_init,
883 		.bc_ops = &xfs_refcountbt_ops,
884 		.need_init = xfs_has_reflink(mp)
885 	},
886 	{ /* NULL terminating block */
887 		.daddr = XFS_BUF_DADDR_NULL,
888 	}
889 	};
890 	struct  xfs_aghdr_grow_data *dp;
891 	int			error = 0;
892 
893 	/* Account for AG free space in new AG */
894 	id->nfree += id->agsize - mp->m_ag_prealloc_blocks;
895 	for (dp = &aghdr_data[0]; dp->daddr != XFS_BUF_DADDR_NULL; dp++) {
896 		if (!dp->need_init)
897 			continue;
898 
899 		id->daddr = dp->daddr;
900 		id->numblks = dp->numblks;
901 		id->bc_ops = dp->bc_ops;
902 		error = xfs_ag_init_hdr(mp, id, dp->work, dp->ops);
903 		if (error)
904 			break;
905 	}
906 	return error;
907 }
908 
909 int
910 xfs_ag_shrink_space(
911 	struct xfs_perag	*pag,
912 	struct xfs_trans	**tpp,
913 	xfs_extlen_t		delta)
914 {
915 	struct xfs_mount	*mp = pag->pag_mount;
916 	struct xfs_alloc_arg	args = {
917 		.tp	= *tpp,
918 		.mp	= mp,
919 		.pag	= pag,
920 		.minlen = delta,
921 		.maxlen = delta,
922 		.oinfo	= XFS_RMAP_OINFO_SKIP_UPDATE,
923 		.resv	= XFS_AG_RESV_NONE,
924 		.prod	= 1
925 	};
926 	struct xfs_buf		*agibp, *agfbp;
927 	struct xfs_agi		*agi;
928 	struct xfs_agf		*agf;
929 	xfs_agblock_t		aglen;
930 	int			error, err2;
931 
932 	ASSERT(pag->pag_agno == mp->m_sb.sb_agcount - 1);
933 	error = xfs_ialloc_read_agi(pag, *tpp, &agibp);
934 	if (error)
935 		return error;
936 
937 	agi = agibp->b_addr;
938 
939 	error = xfs_alloc_read_agf(pag, *tpp, 0, &agfbp);
940 	if (error)
941 		return error;
942 
943 	agf = agfbp->b_addr;
944 	aglen = be32_to_cpu(agi->agi_length);
945 	/* some extra paranoid checks before we shrink the ag */
946 	if (XFS_IS_CORRUPT(mp, agf->agf_length != agi->agi_length)) {
947 		xfs_ag_mark_sick(pag, XFS_SICK_AG_AGF);
948 		return -EFSCORRUPTED;
949 	}
950 	if (delta >= aglen)
951 		return -EINVAL;
952 
953 	/*
954 	 * Make sure that the last inode cluster cannot overlap with the new
955 	 * end of the AG, even if it's sparse.
956 	 */
957 	error = xfs_ialloc_check_shrink(pag, *tpp, agibp, aglen - delta);
958 	if (error)
959 		return error;
960 
961 	/*
962 	 * Disable perag reservations so it doesn't cause the allocation request
963 	 * to fail. We'll reestablish reservation before we return.
964 	 */
965 	error = xfs_ag_resv_free(pag);
966 	if (error)
967 		return error;
968 
969 	/* internal log shouldn't also show up in the free space btrees */
970 	error = xfs_alloc_vextent_exact_bno(&args,
971 			XFS_AGB_TO_FSB(mp, pag->pag_agno, aglen - delta));
972 	if (!error && args.agbno == NULLAGBLOCK)
973 		error = -ENOSPC;
974 
975 	if (error) {
976 		/*
977 		 * if extent allocation fails, need to roll the transaction to
978 		 * ensure that the AGFL fixup has been committed anyway.
979 		 */
980 		xfs_trans_bhold(*tpp, agfbp);
981 		err2 = xfs_trans_roll(tpp);
982 		if (err2)
983 			return err2;
984 		xfs_trans_bjoin(*tpp, agfbp);
985 		goto resv_init_out;
986 	}
987 
988 	/*
989 	 * if successfully deleted from freespace btrees, need to confirm
990 	 * per-AG reservation works as expected.
991 	 */
992 	be32_add_cpu(&agi->agi_length, -delta);
993 	be32_add_cpu(&agf->agf_length, -delta);
994 
995 	err2 = xfs_ag_resv_init(pag, *tpp);
996 	if (err2) {
997 		be32_add_cpu(&agi->agi_length, delta);
998 		be32_add_cpu(&agf->agf_length, delta);
999 		if (err2 != -ENOSPC)
1000 			goto resv_err;
1001 
1002 		err2 = xfs_free_extent_later(*tpp, args.fsbno, delta, NULL,
1003 				XFS_AG_RESV_NONE, true);
1004 		if (err2)
1005 			goto resv_err;
1006 
1007 		/*
1008 		 * Roll the transaction before trying to re-init the per-ag
1009 		 * reservation. The new transaction is clean so it will cancel
1010 		 * without any side effects.
1011 		 */
1012 		error = xfs_defer_finish(tpp);
1013 		if (error)
1014 			return error;
1015 
1016 		error = -ENOSPC;
1017 		goto resv_init_out;
1018 	}
1019 
1020 	/* Update perag geometry */
1021 	pag->block_count -= delta;
1022 	__xfs_agino_range(pag->pag_mount, pag->block_count, &pag->agino_min,
1023 				&pag->agino_max);
1024 
1025 	xfs_ialloc_log_agi(*tpp, agibp, XFS_AGI_LENGTH);
1026 	xfs_alloc_log_agf(*tpp, agfbp, XFS_AGF_LENGTH);
1027 	return 0;
1028 
1029 resv_init_out:
1030 	err2 = xfs_ag_resv_init(pag, *tpp);
1031 	if (!err2)
1032 		return error;
1033 resv_err:
1034 	xfs_warn(mp, "Error %d reserving per-AG metadata reserve pool.", err2);
1035 	xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
1036 	return err2;
1037 }
1038 
1039 /*
1040  * Extent the AG indicated by the @id by the length passed in
1041  */
1042 int
1043 xfs_ag_extend_space(
1044 	struct xfs_perag	*pag,
1045 	struct xfs_trans	*tp,
1046 	xfs_extlen_t		len)
1047 {
1048 	struct xfs_buf		*bp;
1049 	struct xfs_agi		*agi;
1050 	struct xfs_agf		*agf;
1051 	int			error;
1052 
1053 	ASSERT(pag->pag_agno == pag->pag_mount->m_sb.sb_agcount - 1);
1054 
1055 	error = xfs_ialloc_read_agi(pag, tp, &bp);
1056 	if (error)
1057 		return error;
1058 
1059 	agi = bp->b_addr;
1060 	be32_add_cpu(&agi->agi_length, len);
1061 	xfs_ialloc_log_agi(tp, bp, XFS_AGI_LENGTH);
1062 
1063 	/*
1064 	 * Change agf length.
1065 	 */
1066 	error = xfs_alloc_read_agf(pag, tp, 0, &bp);
1067 	if (error)
1068 		return error;
1069 
1070 	agf = bp->b_addr;
1071 	be32_add_cpu(&agf->agf_length, len);
1072 	ASSERT(agf->agf_length == agi->agi_length);
1073 	xfs_alloc_log_agf(tp, bp, XFS_AGF_LENGTH);
1074 
1075 	/*
1076 	 * Free the new space.
1077 	 *
1078 	 * XFS_RMAP_OINFO_SKIP_UPDATE is used here to tell the rmap btree that
1079 	 * this doesn't actually exist in the rmap btree.
1080 	 */
1081 	error = xfs_rmap_free(tp, bp, pag, be32_to_cpu(agf->agf_length) - len,
1082 				len, &XFS_RMAP_OINFO_SKIP_UPDATE);
1083 	if (error)
1084 		return error;
1085 
1086 	error = xfs_free_extent(tp, pag, be32_to_cpu(agf->agf_length) - len,
1087 			len, &XFS_RMAP_OINFO_SKIP_UPDATE, XFS_AG_RESV_NONE);
1088 	if (error)
1089 		return error;
1090 
1091 	/* Update perag geometry */
1092 	pag->block_count = be32_to_cpu(agf->agf_length);
1093 	__xfs_agino_range(pag->pag_mount, pag->block_count, &pag->agino_min,
1094 				&pag->agino_max);
1095 	return 0;
1096 }
1097 
1098 /* Retrieve AG geometry. */
1099 int
1100 xfs_ag_get_geometry(
1101 	struct xfs_perag	*pag,
1102 	struct xfs_ag_geometry	*ageo)
1103 {
1104 	struct xfs_buf		*agi_bp;
1105 	struct xfs_buf		*agf_bp;
1106 	struct xfs_agi		*agi;
1107 	struct xfs_agf		*agf;
1108 	unsigned int		freeblks;
1109 	int			error;
1110 
1111 	/* Lock the AG headers. */
1112 	error = xfs_ialloc_read_agi(pag, NULL, &agi_bp);
1113 	if (error)
1114 		return error;
1115 	error = xfs_alloc_read_agf(pag, NULL, 0, &agf_bp);
1116 	if (error)
1117 		goto out_agi;
1118 
1119 	/* Fill out form. */
1120 	memset(ageo, 0, sizeof(*ageo));
1121 	ageo->ag_number = pag->pag_agno;
1122 
1123 	agi = agi_bp->b_addr;
1124 	ageo->ag_icount = be32_to_cpu(agi->agi_count);
1125 	ageo->ag_ifree = be32_to_cpu(agi->agi_freecount);
1126 
1127 	agf = agf_bp->b_addr;
1128 	ageo->ag_length = be32_to_cpu(agf->agf_length);
1129 	freeblks = pag->pagf_freeblks +
1130 		   pag->pagf_flcount +
1131 		   pag->pagf_btreeblks -
1132 		   xfs_ag_resv_needed(pag, XFS_AG_RESV_NONE);
1133 	ageo->ag_freeblks = freeblks;
1134 	xfs_ag_geom_health(pag, ageo);
1135 
1136 	/* Release resources. */
1137 	xfs_buf_relse(agf_bp);
1138 out_agi:
1139 	xfs_buf_relse(agi_bp);
1140 	return error;
1141 }
1142