xref: /openbmc/linux/fs/xfs/libxfs/xfs_ag.c (revision b593bce5)
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 
26 static struct xfs_buf *
27 xfs_get_aghdr_buf(
28 	struct xfs_mount	*mp,
29 	xfs_daddr_t		blkno,
30 	size_t			numblks,
31 	int			flags,
32 	const struct xfs_buf_ops *ops)
33 {
34 	struct xfs_buf		*bp;
35 
36 	bp = xfs_buf_get_uncached(mp->m_ddev_targp, numblks, flags);
37 	if (!bp)
38 		return NULL;
39 
40 	xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
41 	bp->b_bn = blkno;
42 	bp->b_maps[0].bm_bn = blkno;
43 	bp->b_ops = ops;
44 
45 	return bp;
46 }
47 
48 static inline bool is_log_ag(struct xfs_mount *mp, struct aghdr_init_data *id)
49 {
50 	return mp->m_sb.sb_logstart > 0 &&
51 	       id->agno == XFS_FSB_TO_AGNO(mp, mp->m_sb.sb_logstart);
52 }
53 
54 /*
55  * Generic btree root block init function
56  */
57 static void
58 xfs_btroot_init(
59 	struct xfs_mount	*mp,
60 	struct xfs_buf		*bp,
61 	struct aghdr_init_data	*id)
62 {
63 	xfs_btree_init_block(mp, bp, id->type, 0, 0, id->agno);
64 }
65 
66 /* Finish initializing a free space btree. */
67 static void
68 xfs_freesp_init_recs(
69 	struct xfs_mount	*mp,
70 	struct xfs_buf		*bp,
71 	struct aghdr_init_data	*id)
72 {
73 	struct xfs_alloc_rec	*arec;
74 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
75 
76 	arec = XFS_ALLOC_REC_ADDR(mp, XFS_BUF_TO_BLOCK(bp), 1);
77 	arec->ar_startblock = cpu_to_be32(mp->m_ag_prealloc_blocks);
78 
79 	if (is_log_ag(mp, id)) {
80 		struct xfs_alloc_rec	*nrec;
81 		xfs_agblock_t		start = XFS_FSB_TO_AGBNO(mp,
82 							mp->m_sb.sb_logstart);
83 
84 		ASSERT(start >= mp->m_ag_prealloc_blocks);
85 		if (start != mp->m_ag_prealloc_blocks) {
86 			/*
87 			 * Modify first record to pad stripe align of log
88 			 */
89 			arec->ar_blockcount = cpu_to_be32(start -
90 						mp->m_ag_prealloc_blocks);
91 			nrec = arec + 1;
92 
93 			/*
94 			 * Insert second record at start of internal log
95 			 * which then gets trimmed.
96 			 */
97 			nrec->ar_startblock = cpu_to_be32(
98 					be32_to_cpu(arec->ar_startblock) +
99 					be32_to_cpu(arec->ar_blockcount));
100 			arec = nrec;
101 			be16_add_cpu(&block->bb_numrecs, 1);
102 		}
103 		/*
104 		 * Change record start to after the internal log
105 		 */
106 		be32_add_cpu(&arec->ar_startblock, mp->m_sb.sb_logblocks);
107 	}
108 
109 	/*
110 	 * Calculate the record block count and check for the case where
111 	 * the log might have consumed all available space in the AG. If
112 	 * so, reset the record count to 0 to avoid exposure of an invalid
113 	 * record start block.
114 	 */
115 	arec->ar_blockcount = cpu_to_be32(id->agsize -
116 					  be32_to_cpu(arec->ar_startblock));
117 	if (!arec->ar_blockcount)
118 		block->bb_numrecs = 0;
119 }
120 
121 /*
122  * Alloc btree root block init functions
123  */
124 static void
125 xfs_bnoroot_init(
126 	struct xfs_mount	*mp,
127 	struct xfs_buf		*bp,
128 	struct aghdr_init_data	*id)
129 {
130 	xfs_btree_init_block(mp, bp, XFS_BTNUM_BNO, 0, 1, id->agno);
131 	xfs_freesp_init_recs(mp, bp, id);
132 }
133 
134 static void
135 xfs_cntroot_init(
136 	struct xfs_mount	*mp,
137 	struct xfs_buf		*bp,
138 	struct aghdr_init_data	*id)
139 {
140 	xfs_btree_init_block(mp, bp, XFS_BTNUM_CNT, 0, 1, id->agno);
141 	xfs_freesp_init_recs(mp, bp, id);
142 }
143 
144 /*
145  * Reverse map root block init
146  */
147 static void
148 xfs_rmaproot_init(
149 	struct xfs_mount	*mp,
150 	struct xfs_buf		*bp,
151 	struct aghdr_init_data	*id)
152 {
153 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
154 	struct xfs_rmap_rec	*rrec;
155 
156 	xfs_btree_init_block(mp, bp, XFS_BTNUM_RMAP, 0, 4, id->agno);
157 
158 	/*
159 	 * mark the AG header regions as static metadata The BNO
160 	 * btree block is the first block after the headers, so
161 	 * it's location defines the size of region the static
162 	 * metadata consumes.
163 	 *
164 	 * Note: unlike mkfs, we never have to account for log
165 	 * space when growing the data regions
166 	 */
167 	rrec = XFS_RMAP_REC_ADDR(block, 1);
168 	rrec->rm_startblock = 0;
169 	rrec->rm_blockcount = cpu_to_be32(XFS_BNO_BLOCK(mp));
170 	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_FS);
171 	rrec->rm_offset = 0;
172 
173 	/* account freespace btree root blocks */
174 	rrec = XFS_RMAP_REC_ADDR(block, 2);
175 	rrec->rm_startblock = cpu_to_be32(XFS_BNO_BLOCK(mp));
176 	rrec->rm_blockcount = cpu_to_be32(2);
177 	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
178 	rrec->rm_offset = 0;
179 
180 	/* account inode btree root blocks */
181 	rrec = XFS_RMAP_REC_ADDR(block, 3);
182 	rrec->rm_startblock = cpu_to_be32(XFS_IBT_BLOCK(mp));
183 	rrec->rm_blockcount = cpu_to_be32(XFS_RMAP_BLOCK(mp) -
184 					  XFS_IBT_BLOCK(mp));
185 	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_INOBT);
186 	rrec->rm_offset = 0;
187 
188 	/* account for rmap btree root */
189 	rrec = XFS_RMAP_REC_ADDR(block, 4);
190 	rrec->rm_startblock = cpu_to_be32(XFS_RMAP_BLOCK(mp));
191 	rrec->rm_blockcount = cpu_to_be32(1);
192 	rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
193 	rrec->rm_offset = 0;
194 
195 	/* account for refc btree root */
196 	if (xfs_sb_version_hasreflink(&mp->m_sb)) {
197 		rrec = XFS_RMAP_REC_ADDR(block, 5);
198 		rrec->rm_startblock = cpu_to_be32(xfs_refc_block(mp));
199 		rrec->rm_blockcount = cpu_to_be32(1);
200 		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_REFC);
201 		rrec->rm_offset = 0;
202 		be16_add_cpu(&block->bb_numrecs, 1);
203 	}
204 
205 	/* account for the log space */
206 	if (is_log_ag(mp, id)) {
207 		rrec = XFS_RMAP_REC_ADDR(block,
208 				be16_to_cpu(block->bb_numrecs) + 1);
209 		rrec->rm_startblock = cpu_to_be32(
210 				XFS_FSB_TO_AGBNO(mp, mp->m_sb.sb_logstart));
211 		rrec->rm_blockcount = cpu_to_be32(mp->m_sb.sb_logblocks);
212 		rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_LOG);
213 		rrec->rm_offset = 0;
214 		be16_add_cpu(&block->bb_numrecs, 1);
215 	}
216 }
217 
218 /*
219  * Initialise new secondary superblocks with the pre-grow geometry, but mark
220  * them as "in progress" so we know they haven't yet been activated. This will
221  * get cleared when the update with the new geometry information is done after
222  * changes to the primary are committed. This isn't strictly necessary, but we
223  * get it for free with the delayed buffer write lists and it means we can tell
224  * if a grow operation didn't complete properly after the fact.
225  */
226 static void
227 xfs_sbblock_init(
228 	struct xfs_mount	*mp,
229 	struct xfs_buf		*bp,
230 	struct aghdr_init_data	*id)
231 {
232 	struct xfs_dsb		*dsb = XFS_BUF_TO_SBP(bp);
233 
234 	xfs_sb_to_disk(dsb, &mp->m_sb);
235 	dsb->sb_inprogress = 1;
236 }
237 
238 static void
239 xfs_agfblock_init(
240 	struct xfs_mount	*mp,
241 	struct xfs_buf		*bp,
242 	struct aghdr_init_data	*id)
243 {
244 	struct xfs_agf		*agf = XFS_BUF_TO_AGF(bp);
245 	xfs_extlen_t		tmpsize;
246 
247 	agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
248 	agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
249 	agf->agf_seqno = cpu_to_be32(id->agno);
250 	agf->agf_length = cpu_to_be32(id->agsize);
251 	agf->agf_roots[XFS_BTNUM_BNOi] = cpu_to_be32(XFS_BNO_BLOCK(mp));
252 	agf->agf_roots[XFS_BTNUM_CNTi] = cpu_to_be32(XFS_CNT_BLOCK(mp));
253 	agf->agf_levels[XFS_BTNUM_BNOi] = cpu_to_be32(1);
254 	agf->agf_levels[XFS_BTNUM_CNTi] = cpu_to_be32(1);
255 	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
256 		agf->agf_roots[XFS_BTNUM_RMAPi] =
257 					cpu_to_be32(XFS_RMAP_BLOCK(mp));
258 		agf->agf_levels[XFS_BTNUM_RMAPi] = cpu_to_be32(1);
259 		agf->agf_rmap_blocks = cpu_to_be32(1);
260 	}
261 
262 	agf->agf_flfirst = cpu_to_be32(1);
263 	agf->agf_fllast = 0;
264 	agf->agf_flcount = 0;
265 	tmpsize = id->agsize - mp->m_ag_prealloc_blocks;
266 	agf->agf_freeblks = cpu_to_be32(tmpsize);
267 	agf->agf_longest = cpu_to_be32(tmpsize);
268 	if (xfs_sb_version_hascrc(&mp->m_sb))
269 		uuid_copy(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid);
270 	if (xfs_sb_version_hasreflink(&mp->m_sb)) {
271 		agf->agf_refcount_root = cpu_to_be32(
272 				xfs_refc_block(mp));
273 		agf->agf_refcount_level = cpu_to_be32(1);
274 		agf->agf_refcount_blocks = cpu_to_be32(1);
275 	}
276 
277 	if (is_log_ag(mp, id)) {
278 		int64_t	logblocks = mp->m_sb.sb_logblocks;
279 
280 		be32_add_cpu(&agf->agf_freeblks, -logblocks);
281 		agf->agf_longest = cpu_to_be32(id->agsize -
282 			XFS_FSB_TO_AGBNO(mp, mp->m_sb.sb_logstart) - logblocks);
283 	}
284 }
285 
286 static void
287 xfs_agflblock_init(
288 	struct xfs_mount	*mp,
289 	struct xfs_buf		*bp,
290 	struct aghdr_init_data	*id)
291 {
292 	struct xfs_agfl		*agfl = XFS_BUF_TO_AGFL(bp);
293 	__be32			*agfl_bno;
294 	int			bucket;
295 
296 	if (xfs_sb_version_hascrc(&mp->m_sb)) {
297 		agfl->agfl_magicnum = cpu_to_be32(XFS_AGFL_MAGIC);
298 		agfl->agfl_seqno = cpu_to_be32(id->agno);
299 		uuid_copy(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid);
300 	}
301 
302 	agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, bp);
303 	for (bucket = 0; bucket < xfs_agfl_size(mp); bucket++)
304 		agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK);
305 }
306 
307 static void
308 xfs_agiblock_init(
309 	struct xfs_mount	*mp,
310 	struct xfs_buf		*bp,
311 	struct aghdr_init_data	*id)
312 {
313 	struct xfs_agi		*agi = XFS_BUF_TO_AGI(bp);
314 	int			bucket;
315 
316 	agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
317 	agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
318 	agi->agi_seqno = cpu_to_be32(id->agno);
319 	agi->agi_length = cpu_to_be32(id->agsize);
320 	agi->agi_count = 0;
321 	agi->agi_root = cpu_to_be32(XFS_IBT_BLOCK(mp));
322 	agi->agi_level = cpu_to_be32(1);
323 	agi->agi_freecount = 0;
324 	agi->agi_newino = cpu_to_be32(NULLAGINO);
325 	agi->agi_dirino = cpu_to_be32(NULLAGINO);
326 	if (xfs_sb_version_hascrc(&mp->m_sb))
327 		uuid_copy(&agi->agi_uuid, &mp->m_sb.sb_meta_uuid);
328 	if (xfs_sb_version_hasfinobt(&mp->m_sb)) {
329 		agi->agi_free_root = cpu_to_be32(XFS_FIBT_BLOCK(mp));
330 		agi->agi_free_level = cpu_to_be32(1);
331 	}
332 	for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
333 		agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
334 }
335 
336 typedef void (*aghdr_init_work_f)(struct xfs_mount *mp, struct xfs_buf *bp,
337 				  struct aghdr_init_data *id);
338 static int
339 xfs_ag_init_hdr(
340 	struct xfs_mount	*mp,
341 	struct aghdr_init_data	*id,
342 	aghdr_init_work_f	work,
343 	const struct xfs_buf_ops *ops)
344 
345 {
346 	struct xfs_buf		*bp;
347 
348 	bp = xfs_get_aghdr_buf(mp, id->daddr, id->numblks, 0, ops);
349 	if (!bp)
350 		return -ENOMEM;
351 
352 	(*work)(mp, bp, id);
353 
354 	xfs_buf_delwri_queue(bp, &id->buffer_list);
355 	xfs_buf_relse(bp);
356 	return 0;
357 }
358 
359 struct xfs_aghdr_grow_data {
360 	xfs_daddr_t		daddr;
361 	size_t			numblks;
362 	const struct xfs_buf_ops *ops;
363 	aghdr_init_work_f	work;
364 	xfs_btnum_t		type;
365 	bool			need_init;
366 };
367 
368 /*
369  * Prepare new AG headers to be written to disk. We use uncached buffers here,
370  * as it is assumed these new AG headers are currently beyond the currently
371  * valid filesystem address space. Using cached buffers would trip over EOFS
372  * corruption detection alogrithms in the buffer cache lookup routines.
373  *
374  * This is a non-transactional function, but the prepared buffers are added to a
375  * delayed write buffer list supplied by the caller so they can submit them to
376  * disk and wait on them as required.
377  */
378 int
379 xfs_ag_init_headers(
380 	struct xfs_mount	*mp,
381 	struct aghdr_init_data	*id)
382 
383 {
384 	struct xfs_aghdr_grow_data aghdr_data[] = {
385 	{ /* SB */
386 		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_SB_DADDR),
387 		.numblks = XFS_FSS_TO_BB(mp, 1),
388 		.ops = &xfs_sb_buf_ops,
389 		.work = &xfs_sbblock_init,
390 		.need_init = true
391 	},
392 	{ /* AGF */
393 		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGF_DADDR(mp)),
394 		.numblks = XFS_FSS_TO_BB(mp, 1),
395 		.ops = &xfs_agf_buf_ops,
396 		.work = &xfs_agfblock_init,
397 		.need_init = true
398 	},
399 	{ /* AGFL */
400 		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGFL_DADDR(mp)),
401 		.numblks = XFS_FSS_TO_BB(mp, 1),
402 		.ops = &xfs_agfl_buf_ops,
403 		.work = &xfs_agflblock_init,
404 		.need_init = true
405 	},
406 	{ /* AGI */
407 		.daddr = XFS_AG_DADDR(mp, id->agno, XFS_AGI_DADDR(mp)),
408 		.numblks = XFS_FSS_TO_BB(mp, 1),
409 		.ops = &xfs_agi_buf_ops,
410 		.work = &xfs_agiblock_init,
411 		.need_init = true
412 	},
413 	{ /* BNO root block */
414 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_BNO_BLOCK(mp)),
415 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
416 		.ops = &xfs_bnobt_buf_ops,
417 		.work = &xfs_bnoroot_init,
418 		.need_init = true
419 	},
420 	{ /* CNT root block */
421 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_CNT_BLOCK(mp)),
422 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
423 		.ops = &xfs_cntbt_buf_ops,
424 		.work = &xfs_cntroot_init,
425 		.need_init = true
426 	},
427 	{ /* INO root block */
428 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_IBT_BLOCK(mp)),
429 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
430 		.ops = &xfs_inobt_buf_ops,
431 		.work = &xfs_btroot_init,
432 		.type = XFS_BTNUM_INO,
433 		.need_init = true
434 	},
435 	{ /* FINO root block */
436 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_FIBT_BLOCK(mp)),
437 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
438 		.ops = &xfs_finobt_buf_ops,
439 		.work = &xfs_btroot_init,
440 		.type = XFS_BTNUM_FINO,
441 		.need_init =  xfs_sb_version_hasfinobt(&mp->m_sb)
442 	},
443 	{ /* RMAP root block */
444 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, XFS_RMAP_BLOCK(mp)),
445 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
446 		.ops = &xfs_rmapbt_buf_ops,
447 		.work = &xfs_rmaproot_init,
448 		.need_init = xfs_sb_version_hasrmapbt(&mp->m_sb)
449 	},
450 	{ /* REFC root block */
451 		.daddr = XFS_AGB_TO_DADDR(mp, id->agno, xfs_refc_block(mp)),
452 		.numblks = BTOBB(mp->m_sb.sb_blocksize),
453 		.ops = &xfs_refcountbt_buf_ops,
454 		.work = &xfs_btroot_init,
455 		.type = XFS_BTNUM_REFC,
456 		.need_init = xfs_sb_version_hasreflink(&mp->m_sb)
457 	},
458 	{ /* NULL terminating block */
459 		.daddr = XFS_BUF_DADDR_NULL,
460 	}
461 	};
462 	struct  xfs_aghdr_grow_data *dp;
463 	int			error = 0;
464 
465 	/* Account for AG free space in new AG */
466 	id->nfree += id->agsize - mp->m_ag_prealloc_blocks;
467 	for (dp = &aghdr_data[0]; dp->daddr != XFS_BUF_DADDR_NULL; dp++) {
468 		if (!dp->need_init)
469 			continue;
470 
471 		id->daddr = dp->daddr;
472 		id->numblks = dp->numblks;
473 		id->type = dp->type;
474 		error = xfs_ag_init_hdr(mp, id, dp->work, dp->ops);
475 		if (error)
476 			break;
477 	}
478 	return error;
479 }
480 
481 /*
482  * Extent the AG indicated by the @id by the length passed in
483  */
484 int
485 xfs_ag_extend_space(
486 	struct xfs_mount	*mp,
487 	struct xfs_trans	*tp,
488 	struct aghdr_init_data	*id,
489 	xfs_extlen_t		len)
490 {
491 	struct xfs_buf		*bp;
492 	struct xfs_agi		*agi;
493 	struct xfs_agf		*agf;
494 	int			error;
495 
496 	/*
497 	 * Change the agi length.
498 	 */
499 	error = xfs_ialloc_read_agi(mp, tp, id->agno, &bp);
500 	if (error)
501 		return error;
502 
503 	agi = XFS_BUF_TO_AGI(bp);
504 	be32_add_cpu(&agi->agi_length, len);
505 	ASSERT(id->agno == mp->m_sb.sb_agcount - 1 ||
506 	       be32_to_cpu(agi->agi_length) == mp->m_sb.sb_agblocks);
507 	xfs_ialloc_log_agi(tp, bp, XFS_AGI_LENGTH);
508 
509 	/*
510 	 * Change agf length.
511 	 */
512 	error = xfs_alloc_read_agf(mp, tp, id->agno, 0, &bp);
513 	if (error)
514 		return error;
515 
516 	agf = XFS_BUF_TO_AGF(bp);
517 	be32_add_cpu(&agf->agf_length, len);
518 	ASSERT(agf->agf_length == agi->agi_length);
519 	xfs_alloc_log_agf(tp, bp, XFS_AGF_LENGTH);
520 
521 	/*
522 	 * Free the new space.
523 	 *
524 	 * XFS_RMAP_OINFO_SKIP_UPDATE is used here to tell the rmap btree that
525 	 * this doesn't actually exist in the rmap btree.
526 	 */
527 	error = xfs_rmap_free(tp, bp, id->agno,
528 				be32_to_cpu(agf->agf_length) - len,
529 				len, &XFS_RMAP_OINFO_SKIP_UPDATE);
530 	if (error)
531 		return error;
532 
533 	return  xfs_free_extent(tp, XFS_AGB_TO_FSB(mp, id->agno,
534 					be32_to_cpu(agf->agf_length) - len),
535 				len, &XFS_RMAP_OINFO_SKIP_UPDATE,
536 				XFS_AG_RESV_NONE);
537 }
538 
539 /* Retrieve AG geometry. */
540 int
541 xfs_ag_get_geometry(
542 	struct xfs_mount	*mp,
543 	xfs_agnumber_t		agno,
544 	struct xfs_ag_geometry	*ageo)
545 {
546 	struct xfs_buf		*agi_bp;
547 	struct xfs_buf		*agf_bp;
548 	struct xfs_agi		*agi;
549 	struct xfs_agf		*agf;
550 	struct xfs_perag	*pag;
551 	unsigned int		freeblks;
552 	int			error;
553 
554 	if (agno >= mp->m_sb.sb_agcount)
555 		return -EINVAL;
556 
557 	/* Lock the AG headers. */
558 	error = xfs_ialloc_read_agi(mp, NULL, agno, &agi_bp);
559 	if (error)
560 		return error;
561 	error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agf_bp);
562 	if (error)
563 		goto out_agi;
564 	pag = xfs_perag_get(mp, agno);
565 
566 	/* Fill out form. */
567 	memset(ageo, 0, sizeof(*ageo));
568 	ageo->ag_number = agno;
569 
570 	agi = XFS_BUF_TO_AGI(agi_bp);
571 	ageo->ag_icount = be32_to_cpu(agi->agi_count);
572 	ageo->ag_ifree = be32_to_cpu(agi->agi_freecount);
573 
574 	agf = XFS_BUF_TO_AGF(agf_bp);
575 	ageo->ag_length = be32_to_cpu(agf->agf_length);
576 	freeblks = pag->pagf_freeblks +
577 		   pag->pagf_flcount +
578 		   pag->pagf_btreeblks -
579 		   xfs_ag_resv_needed(pag, XFS_AG_RESV_NONE);
580 	ageo->ag_freeblks = freeblks;
581 	xfs_ag_geom_health(pag, ageo);
582 
583 	/* Release resources. */
584 	xfs_perag_put(pag);
585 	xfs_buf_relse(agf_bp);
586 out_agi:
587 	xfs_buf_relse(agi_bp);
588 	return error;
589 }
590