xref: /openbmc/linux/fs/xfs/xfs_refcount_item.c (revision 63705da3)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2016 Oracle.  All Rights Reserved.
4  * Author: Darrick J. Wong <darrick.wong@oracle.com>
5  */
6 #include "xfs.h"
7 #include "xfs_fs.h"
8 #include "xfs_format.h"
9 #include "xfs_log_format.h"
10 #include "xfs_trans_resv.h"
11 #include "xfs_bit.h"
12 #include "xfs_shared.h"
13 #include "xfs_mount.h"
14 #include "xfs_defer.h"
15 #include "xfs_trans.h"
16 #include "xfs_trans_priv.h"
17 #include "xfs_refcount_item.h"
18 #include "xfs_log.h"
19 #include "xfs_refcount.h"
20 #include "xfs_error.h"
21 #include "xfs_log_priv.h"
22 #include "xfs_log_recover.h"
23 
24 struct kmem_cache	*xfs_cui_cache;
25 struct kmem_cache	*xfs_cud_cache;
26 
27 static const struct xfs_item_ops xfs_cui_item_ops;
28 
29 static inline struct xfs_cui_log_item *CUI_ITEM(struct xfs_log_item *lip)
30 {
31 	return container_of(lip, struct xfs_cui_log_item, cui_item);
32 }
33 
34 STATIC void
35 xfs_cui_item_free(
36 	struct xfs_cui_log_item	*cuip)
37 {
38 	if (cuip->cui_format.cui_nextents > XFS_CUI_MAX_FAST_EXTENTS)
39 		kmem_free(cuip);
40 	else
41 		kmem_cache_free(xfs_cui_cache, cuip);
42 }
43 
44 /*
45  * Freeing the CUI requires that we remove it from the AIL if it has already
46  * been placed there. However, the CUI may not yet have been placed in the AIL
47  * when called by xfs_cui_release() from CUD processing due to the ordering of
48  * committed vs unpin operations in bulk insert operations. Hence the reference
49  * count to ensure only the last caller frees the CUI.
50  */
51 STATIC void
52 xfs_cui_release(
53 	struct xfs_cui_log_item	*cuip)
54 {
55 	ASSERT(atomic_read(&cuip->cui_refcount) > 0);
56 	if (atomic_dec_and_test(&cuip->cui_refcount)) {
57 		xfs_trans_ail_delete(&cuip->cui_item, SHUTDOWN_LOG_IO_ERROR);
58 		xfs_cui_item_free(cuip);
59 	}
60 }
61 
62 
63 STATIC void
64 xfs_cui_item_size(
65 	struct xfs_log_item	*lip,
66 	int			*nvecs,
67 	int			*nbytes)
68 {
69 	struct xfs_cui_log_item	*cuip = CUI_ITEM(lip);
70 
71 	*nvecs += 1;
72 	*nbytes += xfs_cui_log_format_sizeof(cuip->cui_format.cui_nextents);
73 }
74 
75 /*
76  * This is called to fill in the vector of log iovecs for the
77  * given cui log item. We use only 1 iovec, and we point that
78  * at the cui_log_format structure embedded in the cui item.
79  * It is at this point that we assert that all of the extent
80  * slots in the cui item have been filled.
81  */
82 STATIC void
83 xfs_cui_item_format(
84 	struct xfs_log_item	*lip,
85 	struct xfs_log_vec	*lv)
86 {
87 	struct xfs_cui_log_item	*cuip = CUI_ITEM(lip);
88 	struct xfs_log_iovec	*vecp = NULL;
89 
90 	ASSERT(atomic_read(&cuip->cui_next_extent) ==
91 			cuip->cui_format.cui_nextents);
92 
93 	cuip->cui_format.cui_type = XFS_LI_CUI;
94 	cuip->cui_format.cui_size = 1;
95 
96 	xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_CUI_FORMAT, &cuip->cui_format,
97 			xfs_cui_log_format_sizeof(cuip->cui_format.cui_nextents));
98 }
99 
100 /*
101  * The unpin operation is the last place an CUI is manipulated in the log. It is
102  * either inserted in the AIL or aborted in the event of a log I/O error. In
103  * either case, the CUI transaction has been successfully committed to make it
104  * this far. Therefore, we expect whoever committed the CUI to either construct
105  * and commit the CUD or drop the CUD's reference in the event of error. Simply
106  * drop the log's CUI reference now that the log is done with it.
107  */
108 STATIC void
109 xfs_cui_item_unpin(
110 	struct xfs_log_item	*lip,
111 	int			remove)
112 {
113 	struct xfs_cui_log_item	*cuip = CUI_ITEM(lip);
114 
115 	xfs_cui_release(cuip);
116 }
117 
118 /*
119  * The CUI has been either committed or aborted if the transaction has been
120  * cancelled. If the transaction was cancelled, an CUD isn't going to be
121  * constructed and thus we free the CUI here directly.
122  */
123 STATIC void
124 xfs_cui_item_release(
125 	struct xfs_log_item	*lip)
126 {
127 	xfs_cui_release(CUI_ITEM(lip));
128 }
129 
130 /*
131  * Allocate and initialize an cui item with the given number of extents.
132  */
133 STATIC struct xfs_cui_log_item *
134 xfs_cui_init(
135 	struct xfs_mount		*mp,
136 	uint				nextents)
137 
138 {
139 	struct xfs_cui_log_item		*cuip;
140 
141 	ASSERT(nextents > 0);
142 	if (nextents > XFS_CUI_MAX_FAST_EXTENTS)
143 		cuip = kmem_zalloc(xfs_cui_log_item_sizeof(nextents),
144 				0);
145 	else
146 		cuip = kmem_cache_zalloc(xfs_cui_cache,
147 					 GFP_KERNEL | __GFP_NOFAIL);
148 
149 	xfs_log_item_init(mp, &cuip->cui_item, XFS_LI_CUI, &xfs_cui_item_ops);
150 	cuip->cui_format.cui_nextents = nextents;
151 	cuip->cui_format.cui_id = (uintptr_t)(void *)cuip;
152 	atomic_set(&cuip->cui_next_extent, 0);
153 	atomic_set(&cuip->cui_refcount, 2);
154 
155 	return cuip;
156 }
157 
158 static inline struct xfs_cud_log_item *CUD_ITEM(struct xfs_log_item *lip)
159 {
160 	return container_of(lip, struct xfs_cud_log_item, cud_item);
161 }
162 
163 STATIC void
164 xfs_cud_item_size(
165 	struct xfs_log_item	*lip,
166 	int			*nvecs,
167 	int			*nbytes)
168 {
169 	*nvecs += 1;
170 	*nbytes += sizeof(struct xfs_cud_log_format);
171 }
172 
173 /*
174  * This is called to fill in the vector of log iovecs for the
175  * given cud log item. We use only 1 iovec, and we point that
176  * at the cud_log_format structure embedded in the cud item.
177  * It is at this point that we assert that all of the extent
178  * slots in the cud item have been filled.
179  */
180 STATIC void
181 xfs_cud_item_format(
182 	struct xfs_log_item	*lip,
183 	struct xfs_log_vec	*lv)
184 {
185 	struct xfs_cud_log_item	*cudp = CUD_ITEM(lip);
186 	struct xfs_log_iovec	*vecp = NULL;
187 
188 	cudp->cud_format.cud_type = XFS_LI_CUD;
189 	cudp->cud_format.cud_size = 1;
190 
191 	xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_CUD_FORMAT, &cudp->cud_format,
192 			sizeof(struct xfs_cud_log_format));
193 }
194 
195 /*
196  * The CUD is either committed or aborted if the transaction is cancelled. If
197  * the transaction is cancelled, drop our reference to the CUI and free the
198  * CUD.
199  */
200 STATIC void
201 xfs_cud_item_release(
202 	struct xfs_log_item	*lip)
203 {
204 	struct xfs_cud_log_item	*cudp = CUD_ITEM(lip);
205 
206 	xfs_cui_release(cudp->cud_cuip);
207 	kmem_cache_free(xfs_cud_cache, cudp);
208 }
209 
210 static const struct xfs_item_ops xfs_cud_item_ops = {
211 	.flags		= XFS_ITEM_RELEASE_WHEN_COMMITTED,
212 	.iop_size	= xfs_cud_item_size,
213 	.iop_format	= xfs_cud_item_format,
214 	.iop_release	= xfs_cud_item_release,
215 };
216 
217 static struct xfs_cud_log_item *
218 xfs_trans_get_cud(
219 	struct xfs_trans		*tp,
220 	struct xfs_cui_log_item		*cuip)
221 {
222 	struct xfs_cud_log_item		*cudp;
223 
224 	cudp = kmem_cache_zalloc(xfs_cud_cache, GFP_KERNEL | __GFP_NOFAIL);
225 	xfs_log_item_init(tp->t_mountp, &cudp->cud_item, XFS_LI_CUD,
226 			  &xfs_cud_item_ops);
227 	cudp->cud_cuip = cuip;
228 	cudp->cud_format.cud_cui_id = cuip->cui_format.cui_id;
229 
230 	xfs_trans_add_item(tp, &cudp->cud_item);
231 	return cudp;
232 }
233 
234 /*
235  * Finish an refcount update and log it to the CUD. Note that the
236  * transaction is marked dirty regardless of whether the refcount
237  * update succeeds or fails to support the CUI/CUD lifecycle rules.
238  */
239 static int
240 xfs_trans_log_finish_refcount_update(
241 	struct xfs_trans		*tp,
242 	struct xfs_cud_log_item		*cudp,
243 	enum xfs_refcount_intent_type	type,
244 	xfs_fsblock_t			startblock,
245 	xfs_extlen_t			blockcount,
246 	xfs_fsblock_t			*new_fsb,
247 	xfs_extlen_t			*new_len,
248 	struct xfs_btree_cur		**pcur)
249 {
250 	int				error;
251 
252 	error = xfs_refcount_finish_one(tp, type, startblock,
253 			blockcount, new_fsb, new_len, pcur);
254 
255 	/*
256 	 * Mark the transaction dirty, even on error. This ensures the
257 	 * transaction is aborted, which:
258 	 *
259 	 * 1.) releases the CUI and frees the CUD
260 	 * 2.) shuts down the filesystem
261 	 */
262 	tp->t_flags |= XFS_TRANS_DIRTY;
263 	set_bit(XFS_LI_DIRTY, &cudp->cud_item.li_flags);
264 
265 	return error;
266 }
267 
268 /* Sort refcount intents by AG. */
269 static int
270 xfs_refcount_update_diff_items(
271 	void				*priv,
272 	const struct list_head		*a,
273 	const struct list_head		*b)
274 {
275 	struct xfs_mount		*mp = priv;
276 	struct xfs_refcount_intent	*ra;
277 	struct xfs_refcount_intent	*rb;
278 
279 	ra = container_of(a, struct xfs_refcount_intent, ri_list);
280 	rb = container_of(b, struct xfs_refcount_intent, ri_list);
281 	return  XFS_FSB_TO_AGNO(mp, ra->ri_startblock) -
282 		XFS_FSB_TO_AGNO(mp, rb->ri_startblock);
283 }
284 
285 /* Set the phys extent flags for this reverse mapping. */
286 static void
287 xfs_trans_set_refcount_flags(
288 	struct xfs_phys_extent		*refc,
289 	enum xfs_refcount_intent_type	type)
290 {
291 	refc->pe_flags = 0;
292 	switch (type) {
293 	case XFS_REFCOUNT_INCREASE:
294 	case XFS_REFCOUNT_DECREASE:
295 	case XFS_REFCOUNT_ALLOC_COW:
296 	case XFS_REFCOUNT_FREE_COW:
297 		refc->pe_flags |= type;
298 		break;
299 	default:
300 		ASSERT(0);
301 	}
302 }
303 
304 /* Log refcount updates in the intent item. */
305 STATIC void
306 xfs_refcount_update_log_item(
307 	struct xfs_trans		*tp,
308 	struct xfs_cui_log_item		*cuip,
309 	struct xfs_refcount_intent	*refc)
310 {
311 	uint				next_extent;
312 	struct xfs_phys_extent		*ext;
313 
314 	tp->t_flags |= XFS_TRANS_DIRTY;
315 	set_bit(XFS_LI_DIRTY, &cuip->cui_item.li_flags);
316 
317 	/*
318 	 * atomic_inc_return gives us the value after the increment;
319 	 * we want to use it as an array index so we need to subtract 1 from
320 	 * it.
321 	 */
322 	next_extent = atomic_inc_return(&cuip->cui_next_extent) - 1;
323 	ASSERT(next_extent < cuip->cui_format.cui_nextents);
324 	ext = &cuip->cui_format.cui_extents[next_extent];
325 	ext->pe_startblock = refc->ri_startblock;
326 	ext->pe_len = refc->ri_blockcount;
327 	xfs_trans_set_refcount_flags(ext, refc->ri_type);
328 }
329 
330 static struct xfs_log_item *
331 xfs_refcount_update_create_intent(
332 	struct xfs_trans		*tp,
333 	struct list_head		*items,
334 	unsigned int			count,
335 	bool				sort)
336 {
337 	struct xfs_mount		*mp = tp->t_mountp;
338 	struct xfs_cui_log_item		*cuip = xfs_cui_init(mp, count);
339 	struct xfs_refcount_intent	*refc;
340 
341 	ASSERT(count > 0);
342 
343 	xfs_trans_add_item(tp, &cuip->cui_item);
344 	if (sort)
345 		list_sort(mp, items, xfs_refcount_update_diff_items);
346 	list_for_each_entry(refc, items, ri_list)
347 		xfs_refcount_update_log_item(tp, cuip, refc);
348 	return &cuip->cui_item;
349 }
350 
351 /* Get an CUD so we can process all the deferred refcount updates. */
352 static struct xfs_log_item *
353 xfs_refcount_update_create_done(
354 	struct xfs_trans		*tp,
355 	struct xfs_log_item		*intent,
356 	unsigned int			count)
357 {
358 	return &xfs_trans_get_cud(tp, CUI_ITEM(intent))->cud_item;
359 }
360 
361 /* Process a deferred refcount update. */
362 STATIC int
363 xfs_refcount_update_finish_item(
364 	struct xfs_trans		*tp,
365 	struct xfs_log_item		*done,
366 	struct list_head		*item,
367 	struct xfs_btree_cur		**state)
368 {
369 	struct xfs_refcount_intent	*refc;
370 	xfs_fsblock_t			new_fsb;
371 	xfs_extlen_t			new_aglen;
372 	int				error;
373 
374 	refc = container_of(item, struct xfs_refcount_intent, ri_list);
375 	error = xfs_trans_log_finish_refcount_update(tp, CUD_ITEM(done),
376 			refc->ri_type, refc->ri_startblock, refc->ri_blockcount,
377 			&new_fsb, &new_aglen, state);
378 
379 	/* Did we run out of reservation?  Requeue what we didn't finish. */
380 	if (!error && new_aglen > 0) {
381 		ASSERT(refc->ri_type == XFS_REFCOUNT_INCREASE ||
382 		       refc->ri_type == XFS_REFCOUNT_DECREASE);
383 		refc->ri_startblock = new_fsb;
384 		refc->ri_blockcount = new_aglen;
385 		return -EAGAIN;
386 	}
387 	kmem_cache_free(xfs_refcount_intent_cache, refc);
388 	return error;
389 }
390 
391 /* Abort all pending CUIs. */
392 STATIC void
393 xfs_refcount_update_abort_intent(
394 	struct xfs_log_item		*intent)
395 {
396 	xfs_cui_release(CUI_ITEM(intent));
397 }
398 
399 /* Cancel a deferred refcount update. */
400 STATIC void
401 xfs_refcount_update_cancel_item(
402 	struct list_head		*item)
403 {
404 	struct xfs_refcount_intent	*refc;
405 
406 	refc = container_of(item, struct xfs_refcount_intent, ri_list);
407 	kmem_cache_free(xfs_refcount_intent_cache, refc);
408 }
409 
410 const struct xfs_defer_op_type xfs_refcount_update_defer_type = {
411 	.max_items	= XFS_CUI_MAX_FAST_EXTENTS,
412 	.create_intent	= xfs_refcount_update_create_intent,
413 	.abort_intent	= xfs_refcount_update_abort_intent,
414 	.create_done	= xfs_refcount_update_create_done,
415 	.finish_item	= xfs_refcount_update_finish_item,
416 	.finish_cleanup = xfs_refcount_finish_one_cleanup,
417 	.cancel_item	= xfs_refcount_update_cancel_item,
418 };
419 
420 /* Is this recovered CUI ok? */
421 static inline bool
422 xfs_cui_validate_phys(
423 	struct xfs_mount		*mp,
424 	struct xfs_phys_extent		*refc)
425 {
426 	if (!xfs_has_reflink(mp))
427 		return false;
428 
429 	if (refc->pe_flags & ~XFS_REFCOUNT_EXTENT_FLAGS)
430 		return false;
431 
432 	switch (refc->pe_flags & XFS_REFCOUNT_EXTENT_TYPE_MASK) {
433 	case XFS_REFCOUNT_INCREASE:
434 	case XFS_REFCOUNT_DECREASE:
435 	case XFS_REFCOUNT_ALLOC_COW:
436 	case XFS_REFCOUNT_FREE_COW:
437 		break;
438 	default:
439 		return false;
440 	}
441 
442 	return xfs_verify_fsbext(mp, refc->pe_startblock, refc->pe_len);
443 }
444 
445 /*
446  * Process a refcount update intent item that was recovered from the log.
447  * We need to update the refcountbt.
448  */
449 STATIC int
450 xfs_cui_item_recover(
451 	struct xfs_log_item		*lip,
452 	struct list_head		*capture_list)
453 {
454 	struct xfs_bmbt_irec		irec;
455 	struct xfs_cui_log_item		*cuip = CUI_ITEM(lip);
456 	struct xfs_phys_extent		*refc;
457 	struct xfs_cud_log_item		*cudp;
458 	struct xfs_trans		*tp;
459 	struct xfs_btree_cur		*rcur = NULL;
460 	struct xfs_mount		*mp = lip->li_mountp;
461 	xfs_fsblock_t			new_fsb;
462 	xfs_extlen_t			new_len;
463 	unsigned int			refc_type;
464 	bool				requeue_only = false;
465 	enum xfs_refcount_intent_type	type;
466 	int				i;
467 	int				error = 0;
468 
469 	/*
470 	 * First check the validity of the extents described by the
471 	 * CUI.  If any are bad, then assume that all are bad and
472 	 * just toss the CUI.
473 	 */
474 	for (i = 0; i < cuip->cui_format.cui_nextents; i++) {
475 		if (!xfs_cui_validate_phys(mp,
476 					&cuip->cui_format.cui_extents[i])) {
477 			XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
478 					&cuip->cui_format,
479 					sizeof(cuip->cui_format));
480 			return -EFSCORRUPTED;
481 		}
482 	}
483 
484 	/*
485 	 * Under normal operation, refcount updates are deferred, so we
486 	 * wouldn't be adding them directly to a transaction.  All
487 	 * refcount updates manage reservation usage internally and
488 	 * dynamically by deferring work that won't fit in the
489 	 * transaction.  Normally, any work that needs to be deferred
490 	 * gets attached to the same defer_ops that scheduled the
491 	 * refcount update.  However, we're in log recovery here, so we
492 	 * use the passed in defer_ops and to finish up any work that
493 	 * doesn't fit.  We need to reserve enough blocks to handle a
494 	 * full btree split on either end of the refcount range.
495 	 */
496 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate,
497 			mp->m_refc_maxlevels * 2, 0, XFS_TRANS_RESERVE, &tp);
498 	if (error)
499 		return error;
500 
501 	cudp = xfs_trans_get_cud(tp, cuip);
502 
503 	for (i = 0; i < cuip->cui_format.cui_nextents; i++) {
504 		refc = &cuip->cui_format.cui_extents[i];
505 		refc_type = refc->pe_flags & XFS_REFCOUNT_EXTENT_TYPE_MASK;
506 		switch (refc_type) {
507 		case XFS_REFCOUNT_INCREASE:
508 		case XFS_REFCOUNT_DECREASE:
509 		case XFS_REFCOUNT_ALLOC_COW:
510 		case XFS_REFCOUNT_FREE_COW:
511 			type = refc_type;
512 			break;
513 		default:
514 			XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
515 			error = -EFSCORRUPTED;
516 			goto abort_error;
517 		}
518 		if (requeue_only) {
519 			new_fsb = refc->pe_startblock;
520 			new_len = refc->pe_len;
521 		} else
522 			error = xfs_trans_log_finish_refcount_update(tp, cudp,
523 				type, refc->pe_startblock, refc->pe_len,
524 				&new_fsb, &new_len, &rcur);
525 		if (error == -EFSCORRUPTED)
526 			XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
527 					refc, sizeof(*refc));
528 		if (error)
529 			goto abort_error;
530 
531 		/* Requeue what we didn't finish. */
532 		if (new_len > 0) {
533 			irec.br_startblock = new_fsb;
534 			irec.br_blockcount = new_len;
535 			switch (type) {
536 			case XFS_REFCOUNT_INCREASE:
537 				xfs_refcount_increase_extent(tp, &irec);
538 				break;
539 			case XFS_REFCOUNT_DECREASE:
540 				xfs_refcount_decrease_extent(tp, &irec);
541 				break;
542 			case XFS_REFCOUNT_ALLOC_COW:
543 				xfs_refcount_alloc_cow_extent(tp,
544 						irec.br_startblock,
545 						irec.br_blockcount);
546 				break;
547 			case XFS_REFCOUNT_FREE_COW:
548 				xfs_refcount_free_cow_extent(tp,
549 						irec.br_startblock,
550 						irec.br_blockcount);
551 				break;
552 			default:
553 				ASSERT(0);
554 			}
555 			requeue_only = true;
556 		}
557 	}
558 
559 	xfs_refcount_finish_one_cleanup(tp, rcur, error);
560 	return xfs_defer_ops_capture_and_commit(tp, capture_list);
561 
562 abort_error:
563 	xfs_refcount_finish_one_cleanup(tp, rcur, error);
564 	xfs_trans_cancel(tp);
565 	return error;
566 }
567 
568 STATIC bool
569 xfs_cui_item_match(
570 	struct xfs_log_item	*lip,
571 	uint64_t		intent_id)
572 {
573 	return CUI_ITEM(lip)->cui_format.cui_id == intent_id;
574 }
575 
576 /* Relog an intent item to push the log tail forward. */
577 static struct xfs_log_item *
578 xfs_cui_item_relog(
579 	struct xfs_log_item		*intent,
580 	struct xfs_trans		*tp)
581 {
582 	struct xfs_cud_log_item		*cudp;
583 	struct xfs_cui_log_item		*cuip;
584 	struct xfs_phys_extent		*extp;
585 	unsigned int			count;
586 
587 	count = CUI_ITEM(intent)->cui_format.cui_nextents;
588 	extp = CUI_ITEM(intent)->cui_format.cui_extents;
589 
590 	tp->t_flags |= XFS_TRANS_DIRTY;
591 	cudp = xfs_trans_get_cud(tp, CUI_ITEM(intent));
592 	set_bit(XFS_LI_DIRTY, &cudp->cud_item.li_flags);
593 
594 	cuip = xfs_cui_init(tp->t_mountp, count);
595 	memcpy(cuip->cui_format.cui_extents, extp, count * sizeof(*extp));
596 	atomic_set(&cuip->cui_next_extent, count);
597 	xfs_trans_add_item(tp, &cuip->cui_item);
598 	set_bit(XFS_LI_DIRTY, &cuip->cui_item.li_flags);
599 	return &cuip->cui_item;
600 }
601 
602 static const struct xfs_item_ops xfs_cui_item_ops = {
603 	.iop_size	= xfs_cui_item_size,
604 	.iop_format	= xfs_cui_item_format,
605 	.iop_unpin	= xfs_cui_item_unpin,
606 	.iop_release	= xfs_cui_item_release,
607 	.iop_recover	= xfs_cui_item_recover,
608 	.iop_match	= xfs_cui_item_match,
609 	.iop_relog	= xfs_cui_item_relog,
610 };
611 
612 /*
613  * Copy an CUI format buffer from the given buf, and into the destination
614  * CUI format structure.  The CUI/CUD items were designed not to need any
615  * special alignment handling.
616  */
617 static int
618 xfs_cui_copy_format(
619 	struct xfs_log_iovec		*buf,
620 	struct xfs_cui_log_format	*dst_cui_fmt)
621 {
622 	struct xfs_cui_log_format	*src_cui_fmt;
623 	uint				len;
624 
625 	src_cui_fmt = buf->i_addr;
626 	len = xfs_cui_log_format_sizeof(src_cui_fmt->cui_nextents);
627 
628 	if (buf->i_len == len) {
629 		memcpy(dst_cui_fmt, src_cui_fmt, len);
630 		return 0;
631 	}
632 	XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, NULL);
633 	return -EFSCORRUPTED;
634 }
635 
636 /*
637  * This routine is called to create an in-core extent refcount update
638  * item from the cui format structure which was logged on disk.
639  * It allocates an in-core cui, copies the extents from the format
640  * structure into it, and adds the cui to the AIL with the given
641  * LSN.
642  */
643 STATIC int
644 xlog_recover_cui_commit_pass2(
645 	struct xlog			*log,
646 	struct list_head		*buffer_list,
647 	struct xlog_recover_item	*item,
648 	xfs_lsn_t			lsn)
649 {
650 	int				error;
651 	struct xfs_mount		*mp = log->l_mp;
652 	struct xfs_cui_log_item		*cuip;
653 	struct xfs_cui_log_format	*cui_formatp;
654 
655 	cui_formatp = item->ri_buf[0].i_addr;
656 
657 	cuip = xfs_cui_init(mp, cui_formatp->cui_nextents);
658 	error = xfs_cui_copy_format(&item->ri_buf[0], &cuip->cui_format);
659 	if (error) {
660 		xfs_cui_item_free(cuip);
661 		return error;
662 	}
663 	atomic_set(&cuip->cui_next_extent, cui_formatp->cui_nextents);
664 	/*
665 	 * Insert the intent into the AIL directly and drop one reference so
666 	 * that finishing or canceling the work will drop the other.
667 	 */
668 	xfs_trans_ail_insert(log->l_ailp, &cuip->cui_item, lsn);
669 	xfs_cui_release(cuip);
670 	return 0;
671 }
672 
673 const struct xlog_recover_item_ops xlog_cui_item_ops = {
674 	.item_type		= XFS_LI_CUI,
675 	.commit_pass2		= xlog_recover_cui_commit_pass2,
676 };
677 
678 /*
679  * This routine is called when an CUD format structure is found in a committed
680  * transaction in the log. Its purpose is to cancel the corresponding CUI if it
681  * was still in the log. To do this it searches the AIL for the CUI with an id
682  * equal to that in the CUD format structure. If we find it we drop the CUD
683  * reference, which removes the CUI from the AIL and frees it.
684  */
685 STATIC int
686 xlog_recover_cud_commit_pass2(
687 	struct xlog			*log,
688 	struct list_head		*buffer_list,
689 	struct xlog_recover_item	*item,
690 	xfs_lsn_t			lsn)
691 {
692 	struct xfs_cud_log_format	*cud_formatp;
693 
694 	cud_formatp = item->ri_buf[0].i_addr;
695 	if (item->ri_buf[0].i_len != sizeof(struct xfs_cud_log_format)) {
696 		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, log->l_mp);
697 		return -EFSCORRUPTED;
698 	}
699 
700 	xlog_recover_release_intent(log, XFS_LI_CUI, cud_formatp->cud_cui_id);
701 	return 0;
702 }
703 
704 const struct xlog_recover_item_ops xlog_cud_item_ops = {
705 	.item_type		= XFS_LI_CUD,
706 	.commit_pass2		= xlog_recover_cud_commit_pass2,
707 };
708