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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
4  * All Rights Reserved.
5  */
6 #include "xfs.h"
7 #include "xfs_fs.h"
8 #include "xfs_format.h"
9 #include "xfs_log_format.h"
10 #include "xfs_shared.h"
11 #include "xfs_trans_resv.h"
12 #include "xfs_bit.h"
13 #include "xfs_sb.h"
14 #include "xfs_mount.h"
15 #include "xfs_defer.h"
16 #include "xfs_btree.h"
17 #include "xfs_rmap.h"
18 #include "xfs_alloc_btree.h"
19 #include "xfs_alloc.h"
20 #include "xfs_extent_busy.h"
21 #include "xfs_errortag.h"
22 #include "xfs_error.h"
23 #include "xfs_trace.h"
24 #include "xfs_trans.h"
25 #include "xfs_buf_item.h"
26 #include "xfs_log.h"
27 #include "xfs_ag_resv.h"
28 #include "xfs_bmap.h"
29 
30 extern kmem_zone_t	*xfs_bmap_free_item_zone;
31 
32 struct workqueue_struct *xfs_alloc_wq;
33 
34 #define XFS_ABSDIFF(a,b)	(((a) <= (b)) ? ((b) - (a)) : ((a) - (b)))
35 
36 #define	XFSA_FIXUP_BNO_OK	1
37 #define	XFSA_FIXUP_CNT_OK	2
38 
39 STATIC int xfs_alloc_ag_vextent_exact(xfs_alloc_arg_t *);
40 STATIC int xfs_alloc_ag_vextent_near(xfs_alloc_arg_t *);
41 STATIC int xfs_alloc_ag_vextent_size(xfs_alloc_arg_t *);
42 
43 /*
44  * Size of the AGFL.  For CRC-enabled filesystes we steal a couple of slots in
45  * the beginning of the block for a proper header with the location information
46  * and CRC.
47  */
48 unsigned int
xfs_agfl_size(struct xfs_mount * mp)49 xfs_agfl_size(
50 	struct xfs_mount	*mp)
51 {
52 	unsigned int		size = mp->m_sb.sb_sectsize;
53 
54 	if (xfs_sb_version_hascrc(&mp->m_sb))
55 		size -= sizeof(struct xfs_agfl);
56 
57 	return size / sizeof(xfs_agblock_t);
58 }
59 
60 unsigned int
xfs_refc_block(struct xfs_mount * mp)61 xfs_refc_block(
62 	struct xfs_mount	*mp)
63 {
64 	if (xfs_sb_version_hasrmapbt(&mp->m_sb))
65 		return XFS_RMAP_BLOCK(mp) + 1;
66 	if (xfs_sb_version_hasfinobt(&mp->m_sb))
67 		return XFS_FIBT_BLOCK(mp) + 1;
68 	return XFS_IBT_BLOCK(mp) + 1;
69 }
70 
71 xfs_extlen_t
xfs_prealloc_blocks(struct xfs_mount * mp)72 xfs_prealloc_blocks(
73 	struct xfs_mount	*mp)
74 {
75 	if (xfs_sb_version_hasreflink(&mp->m_sb))
76 		return xfs_refc_block(mp) + 1;
77 	if (xfs_sb_version_hasrmapbt(&mp->m_sb))
78 		return XFS_RMAP_BLOCK(mp) + 1;
79 	if (xfs_sb_version_hasfinobt(&mp->m_sb))
80 		return XFS_FIBT_BLOCK(mp) + 1;
81 	return XFS_IBT_BLOCK(mp) + 1;
82 }
83 
84 /*
85  * In order to avoid ENOSPC-related deadlock caused by out-of-order locking of
86  * AGF buffer (PV 947395), we place constraints on the relationship among
87  * actual allocations for data blocks, freelist blocks, and potential file data
88  * bmap btree blocks. However, these restrictions may result in no actual space
89  * allocated for a delayed extent, for example, a data block in a certain AG is
90  * allocated but there is no additional block for the additional bmap btree
91  * block due to a split of the bmap btree of the file. The result of this may
92  * lead to an infinite loop when the file gets flushed to disk and all delayed
93  * extents need to be actually allocated. To get around this, we explicitly set
94  * aside a few blocks which will not be reserved in delayed allocation.
95  *
96  * We need to reserve 4 fsbs _per AG_ for the freelist and 4 more to handle a
97  * potential split of the file's bmap btree.
98  */
99 unsigned int
xfs_alloc_set_aside(struct xfs_mount * mp)100 xfs_alloc_set_aside(
101 	struct xfs_mount	*mp)
102 {
103 	return mp->m_sb.sb_agcount * (XFS_ALLOC_AGFL_RESERVE + 4);
104 }
105 
106 /*
107  * When deciding how much space to allocate out of an AG, we limit the
108  * allocation maximum size to the size the AG. However, we cannot use all the
109  * blocks in the AG - some are permanently used by metadata. These
110  * blocks are generally:
111  *	- the AG superblock, AGF, AGI and AGFL
112  *	- the AGF (bno and cnt) and AGI btree root blocks, and optionally
113  *	  the AGI free inode and rmap btree root blocks.
114  *	- blocks on the AGFL according to xfs_alloc_set_aside() limits
115  *	- the rmapbt root block
116  *
117  * The AG headers are sector sized, so the amount of space they take up is
118  * dependent on filesystem geometry. The others are all single blocks.
119  */
120 unsigned int
xfs_alloc_ag_max_usable(struct xfs_mount * mp)121 xfs_alloc_ag_max_usable(
122 	struct xfs_mount	*mp)
123 {
124 	unsigned int		blocks;
125 
126 	blocks = XFS_BB_TO_FSB(mp, XFS_FSS_TO_BB(mp, 4)); /* ag headers */
127 	blocks += XFS_ALLOC_AGFL_RESERVE;
128 	blocks += 3;			/* AGF, AGI btree root blocks */
129 	if (xfs_sb_version_hasfinobt(&mp->m_sb))
130 		blocks++;		/* finobt root block */
131 	if (xfs_sb_version_hasrmapbt(&mp->m_sb))
132 		blocks++; 		/* rmap root block */
133 	if (xfs_sb_version_hasreflink(&mp->m_sb))
134 		blocks++;		/* refcount root block */
135 
136 	return mp->m_sb.sb_agblocks - blocks;
137 }
138 
139 /*
140  * Lookup the record equal to [bno, len] in the btree given by cur.
141  */
142 STATIC int				/* error */
xfs_alloc_lookup_eq(struct xfs_btree_cur * cur,xfs_agblock_t bno,xfs_extlen_t len,int * stat)143 xfs_alloc_lookup_eq(
144 	struct xfs_btree_cur	*cur,	/* btree cursor */
145 	xfs_agblock_t		bno,	/* starting block of extent */
146 	xfs_extlen_t		len,	/* length of extent */
147 	int			*stat)	/* success/failure */
148 {
149 	int			error;
150 
151 	cur->bc_rec.a.ar_startblock = bno;
152 	cur->bc_rec.a.ar_blockcount = len;
153 	error = xfs_btree_lookup(cur, XFS_LOOKUP_EQ, stat);
154 	cur->bc_ag.abt.active = (*stat == 1);
155 	return error;
156 }
157 
158 /*
159  * Lookup the first record greater than or equal to [bno, len]
160  * in the btree given by cur.
161  */
162 int				/* error */
xfs_alloc_lookup_ge(struct xfs_btree_cur * cur,xfs_agblock_t bno,xfs_extlen_t len,int * stat)163 xfs_alloc_lookup_ge(
164 	struct xfs_btree_cur	*cur,	/* btree cursor */
165 	xfs_agblock_t		bno,	/* starting block of extent */
166 	xfs_extlen_t		len,	/* length of extent */
167 	int			*stat)	/* success/failure */
168 {
169 	int			error;
170 
171 	cur->bc_rec.a.ar_startblock = bno;
172 	cur->bc_rec.a.ar_blockcount = len;
173 	error = xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
174 	cur->bc_ag.abt.active = (*stat == 1);
175 	return error;
176 }
177 
178 /*
179  * Lookup the first record less than or equal to [bno, len]
180  * in the btree given by cur.
181  */
182 int					/* error */
xfs_alloc_lookup_le(struct xfs_btree_cur * cur,xfs_agblock_t bno,xfs_extlen_t len,int * stat)183 xfs_alloc_lookup_le(
184 	struct xfs_btree_cur	*cur,	/* btree cursor */
185 	xfs_agblock_t		bno,	/* starting block of extent */
186 	xfs_extlen_t		len,	/* length of extent */
187 	int			*stat)	/* success/failure */
188 {
189 	int			error;
190 	cur->bc_rec.a.ar_startblock = bno;
191 	cur->bc_rec.a.ar_blockcount = len;
192 	error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
193 	cur->bc_ag.abt.active = (*stat == 1);
194 	return error;
195 }
196 
197 static inline bool
xfs_alloc_cur_active(struct xfs_btree_cur * cur)198 xfs_alloc_cur_active(
199 	struct xfs_btree_cur	*cur)
200 {
201 	return cur && cur->bc_ag.abt.active;
202 }
203 
204 /*
205  * Update the record referred to by cur to the value given
206  * by [bno, len].
207  * This either works (return 0) or gets an EFSCORRUPTED error.
208  */
209 STATIC int				/* error */
xfs_alloc_update(struct xfs_btree_cur * cur,xfs_agblock_t bno,xfs_extlen_t len)210 xfs_alloc_update(
211 	struct xfs_btree_cur	*cur,	/* btree cursor */
212 	xfs_agblock_t		bno,	/* starting block of extent */
213 	xfs_extlen_t		len)	/* length of extent */
214 {
215 	union xfs_btree_rec	rec;
216 
217 	rec.alloc.ar_startblock = cpu_to_be32(bno);
218 	rec.alloc.ar_blockcount = cpu_to_be32(len);
219 	return xfs_btree_update(cur, &rec);
220 }
221 
222 /*
223  * Get the data from the pointed-to record.
224  */
225 int					/* error */
xfs_alloc_get_rec(struct xfs_btree_cur * cur,xfs_agblock_t * bno,xfs_extlen_t * len,int * stat)226 xfs_alloc_get_rec(
227 	struct xfs_btree_cur	*cur,	/* btree cursor */
228 	xfs_agblock_t		*bno,	/* output: starting block of extent */
229 	xfs_extlen_t		*len,	/* output: length of extent */
230 	int			*stat)	/* output: success/failure */
231 {
232 	struct xfs_mount	*mp = cur->bc_mp;
233 	xfs_agnumber_t		agno = cur->bc_ag.agno;
234 	union xfs_btree_rec	*rec;
235 	int			error;
236 
237 	error = xfs_btree_get_rec(cur, &rec, stat);
238 	if (error || !(*stat))
239 		return error;
240 
241 	*bno = be32_to_cpu(rec->alloc.ar_startblock);
242 	*len = be32_to_cpu(rec->alloc.ar_blockcount);
243 
244 	if (*len == 0)
245 		goto out_bad_rec;
246 
247 	/* check for valid extent range, including overflow */
248 	if (!xfs_verify_agbno(mp, agno, *bno))
249 		goto out_bad_rec;
250 	if (*bno > *bno + *len)
251 		goto out_bad_rec;
252 	if (!xfs_verify_agbno(mp, agno, *bno + *len - 1))
253 		goto out_bad_rec;
254 
255 	return 0;
256 
257 out_bad_rec:
258 	xfs_warn(mp,
259 		"%s Freespace BTree record corruption in AG %d detected!",
260 		cur->bc_btnum == XFS_BTNUM_BNO ? "Block" : "Size", agno);
261 	xfs_warn(mp,
262 		"start block 0x%x block count 0x%x", *bno, *len);
263 	return -EFSCORRUPTED;
264 }
265 
266 /*
267  * Compute aligned version of the found extent.
268  * Takes alignment and min length into account.
269  */
270 STATIC bool
xfs_alloc_compute_aligned(xfs_alloc_arg_t * args,xfs_agblock_t foundbno,xfs_extlen_t foundlen,xfs_agblock_t * resbno,xfs_extlen_t * reslen,unsigned * busy_gen)271 xfs_alloc_compute_aligned(
272 	xfs_alloc_arg_t	*args,		/* allocation argument structure */
273 	xfs_agblock_t	foundbno,	/* starting block in found extent */
274 	xfs_extlen_t	foundlen,	/* length in found extent */
275 	xfs_agblock_t	*resbno,	/* result block number */
276 	xfs_extlen_t	*reslen,	/* result length */
277 	unsigned	*busy_gen)
278 {
279 	xfs_agblock_t	bno = foundbno;
280 	xfs_extlen_t	len = foundlen;
281 	xfs_extlen_t	diff;
282 	bool		busy;
283 
284 	/* Trim busy sections out of found extent */
285 	busy = xfs_extent_busy_trim(args, &bno, &len, busy_gen);
286 
287 	/*
288 	 * If we have a largish extent that happens to start before min_agbno,
289 	 * see if we can shift it into range...
290 	 */
291 	if (bno < args->min_agbno && bno + len > args->min_agbno) {
292 		diff = args->min_agbno - bno;
293 		if (len > diff) {
294 			bno += diff;
295 			len -= diff;
296 		}
297 	}
298 
299 	if (args->alignment > 1 && len >= args->minlen) {
300 		xfs_agblock_t	aligned_bno = roundup(bno, args->alignment);
301 
302 		diff = aligned_bno - bno;
303 
304 		*resbno = aligned_bno;
305 		*reslen = diff >= len ? 0 : len - diff;
306 	} else {
307 		*resbno = bno;
308 		*reslen = len;
309 	}
310 
311 	return busy;
312 }
313 
314 /*
315  * Compute best start block and diff for "near" allocations.
316  * freelen >= wantlen already checked by caller.
317  */
318 STATIC xfs_extlen_t			/* difference value (absolute) */
xfs_alloc_compute_diff(xfs_agblock_t wantbno,xfs_extlen_t wantlen,xfs_extlen_t alignment,int datatype,xfs_agblock_t freebno,xfs_extlen_t freelen,xfs_agblock_t * newbnop)319 xfs_alloc_compute_diff(
320 	xfs_agblock_t	wantbno,	/* target starting block */
321 	xfs_extlen_t	wantlen,	/* target length */
322 	xfs_extlen_t	alignment,	/* target alignment */
323 	int		datatype,	/* are we allocating data? */
324 	xfs_agblock_t	freebno,	/* freespace's starting block */
325 	xfs_extlen_t	freelen,	/* freespace's length */
326 	xfs_agblock_t	*newbnop)	/* result: best start block from free */
327 {
328 	xfs_agblock_t	freeend;	/* end of freespace extent */
329 	xfs_agblock_t	newbno1;	/* return block number */
330 	xfs_agblock_t	newbno2;	/* other new block number */
331 	xfs_extlen_t	newlen1=0;	/* length with newbno1 */
332 	xfs_extlen_t	newlen2=0;	/* length with newbno2 */
333 	xfs_agblock_t	wantend;	/* end of target extent */
334 	bool		userdata = datatype & XFS_ALLOC_USERDATA;
335 
336 	ASSERT(freelen >= wantlen);
337 	freeend = freebno + freelen;
338 	wantend = wantbno + wantlen;
339 	/*
340 	 * We want to allocate from the start of a free extent if it is past
341 	 * the desired block or if we are allocating user data and the free
342 	 * extent is before desired block. The second case is there to allow
343 	 * for contiguous allocation from the remaining free space if the file
344 	 * grows in the short term.
345 	 */
346 	if (freebno >= wantbno || (userdata && freeend < wantend)) {
347 		if ((newbno1 = roundup(freebno, alignment)) >= freeend)
348 			newbno1 = NULLAGBLOCK;
349 	} else if (freeend >= wantend && alignment > 1) {
350 		newbno1 = roundup(wantbno, alignment);
351 		newbno2 = newbno1 - alignment;
352 		if (newbno1 >= freeend)
353 			newbno1 = NULLAGBLOCK;
354 		else
355 			newlen1 = XFS_EXTLEN_MIN(wantlen, freeend - newbno1);
356 		if (newbno2 < freebno)
357 			newbno2 = NULLAGBLOCK;
358 		else
359 			newlen2 = XFS_EXTLEN_MIN(wantlen, freeend - newbno2);
360 		if (newbno1 != NULLAGBLOCK && newbno2 != NULLAGBLOCK) {
361 			if (newlen1 < newlen2 ||
362 			    (newlen1 == newlen2 &&
363 			     XFS_ABSDIFF(newbno1, wantbno) >
364 			     XFS_ABSDIFF(newbno2, wantbno)))
365 				newbno1 = newbno2;
366 		} else if (newbno2 != NULLAGBLOCK)
367 			newbno1 = newbno2;
368 	} else if (freeend >= wantend) {
369 		newbno1 = wantbno;
370 	} else if (alignment > 1) {
371 		newbno1 = roundup(freeend - wantlen, alignment);
372 		if (newbno1 > freeend - wantlen &&
373 		    newbno1 - alignment >= freebno)
374 			newbno1 -= alignment;
375 		else if (newbno1 >= freeend)
376 			newbno1 = NULLAGBLOCK;
377 	} else
378 		newbno1 = freeend - wantlen;
379 	*newbnop = newbno1;
380 	return newbno1 == NULLAGBLOCK ? 0 : XFS_ABSDIFF(newbno1, wantbno);
381 }
382 
383 /*
384  * Fix up the length, based on mod and prod.
385  * len should be k * prod + mod for some k.
386  * If len is too small it is returned unchanged.
387  * If len hits maxlen it is left alone.
388  */
389 STATIC void
xfs_alloc_fix_len(xfs_alloc_arg_t * args)390 xfs_alloc_fix_len(
391 	xfs_alloc_arg_t	*args)		/* allocation argument structure */
392 {
393 	xfs_extlen_t	k;
394 	xfs_extlen_t	rlen;
395 
396 	ASSERT(args->mod < args->prod);
397 	rlen = args->len;
398 	ASSERT(rlen >= args->minlen);
399 	ASSERT(rlen <= args->maxlen);
400 	if (args->prod <= 1 || rlen < args->mod || rlen == args->maxlen ||
401 	    (args->mod == 0 && rlen < args->prod))
402 		return;
403 	k = rlen % args->prod;
404 	if (k == args->mod)
405 		return;
406 	if (k > args->mod)
407 		rlen = rlen - (k - args->mod);
408 	else
409 		rlen = rlen - args->prod + (args->mod - k);
410 	/* casts to (int) catch length underflows */
411 	if ((int)rlen < (int)args->minlen)
412 		return;
413 	ASSERT(rlen >= args->minlen && rlen <= args->maxlen);
414 	ASSERT(rlen % args->prod == args->mod);
415 	ASSERT(args->pag->pagf_freeblks + args->pag->pagf_flcount >=
416 		rlen + args->minleft);
417 	args->len = rlen;
418 }
419 
420 /*
421  * Update the two btrees, logically removing from freespace the extent
422  * starting at rbno, rlen blocks.  The extent is contained within the
423  * actual (current) free extent fbno for flen blocks.
424  * Flags are passed in indicating whether the cursors are set to the
425  * relevant records.
426  */
427 STATIC int				/* error code */
xfs_alloc_fixup_trees(xfs_btree_cur_t * cnt_cur,xfs_btree_cur_t * bno_cur,xfs_agblock_t fbno,xfs_extlen_t flen,xfs_agblock_t rbno,xfs_extlen_t rlen,int flags)428 xfs_alloc_fixup_trees(
429 	xfs_btree_cur_t	*cnt_cur,	/* cursor for by-size btree */
430 	xfs_btree_cur_t	*bno_cur,	/* cursor for by-block btree */
431 	xfs_agblock_t	fbno,		/* starting block of free extent */
432 	xfs_extlen_t	flen,		/* length of free extent */
433 	xfs_agblock_t	rbno,		/* starting block of returned extent */
434 	xfs_extlen_t	rlen,		/* length of returned extent */
435 	int		flags)		/* flags, XFSA_FIXUP_... */
436 {
437 	int		error;		/* error code */
438 	int		i;		/* operation results */
439 	xfs_agblock_t	nfbno1;		/* first new free startblock */
440 	xfs_agblock_t	nfbno2;		/* second new free startblock */
441 	xfs_extlen_t	nflen1=0;	/* first new free length */
442 	xfs_extlen_t	nflen2=0;	/* second new free length */
443 	struct xfs_mount *mp;
444 
445 	mp = cnt_cur->bc_mp;
446 
447 	/*
448 	 * Look up the record in the by-size tree if necessary.
449 	 */
450 	if (flags & XFSA_FIXUP_CNT_OK) {
451 #ifdef DEBUG
452 		if ((error = xfs_alloc_get_rec(cnt_cur, &nfbno1, &nflen1, &i)))
453 			return error;
454 		if (XFS_IS_CORRUPT(mp,
455 				   i != 1 ||
456 				   nfbno1 != fbno ||
457 				   nflen1 != flen))
458 			return -EFSCORRUPTED;
459 #endif
460 	} else {
461 		if ((error = xfs_alloc_lookup_eq(cnt_cur, fbno, flen, &i)))
462 			return error;
463 		if (XFS_IS_CORRUPT(mp, i != 1))
464 			return -EFSCORRUPTED;
465 	}
466 	/*
467 	 * Look up the record in the by-block tree if necessary.
468 	 */
469 	if (flags & XFSA_FIXUP_BNO_OK) {
470 #ifdef DEBUG
471 		if ((error = xfs_alloc_get_rec(bno_cur, &nfbno1, &nflen1, &i)))
472 			return error;
473 		if (XFS_IS_CORRUPT(mp,
474 				   i != 1 ||
475 				   nfbno1 != fbno ||
476 				   nflen1 != flen))
477 			return -EFSCORRUPTED;
478 #endif
479 	} else {
480 		if ((error = xfs_alloc_lookup_eq(bno_cur, fbno, flen, &i)))
481 			return error;
482 		if (XFS_IS_CORRUPT(mp, i != 1))
483 			return -EFSCORRUPTED;
484 	}
485 
486 #ifdef DEBUG
487 	if (bno_cur->bc_nlevels == 1 && cnt_cur->bc_nlevels == 1) {
488 		struct xfs_btree_block	*bnoblock;
489 		struct xfs_btree_block	*cntblock;
490 
491 		bnoblock = XFS_BUF_TO_BLOCK(bno_cur->bc_bufs[0]);
492 		cntblock = XFS_BUF_TO_BLOCK(cnt_cur->bc_bufs[0]);
493 
494 		if (XFS_IS_CORRUPT(mp,
495 				   bnoblock->bb_numrecs !=
496 				   cntblock->bb_numrecs))
497 			return -EFSCORRUPTED;
498 	}
499 #endif
500 
501 	/*
502 	 * Deal with all four cases: the allocated record is contained
503 	 * within the freespace record, so we can have new freespace
504 	 * at either (or both) end, or no freespace remaining.
505 	 */
506 	if (rbno == fbno && rlen == flen)
507 		nfbno1 = nfbno2 = NULLAGBLOCK;
508 	else if (rbno == fbno) {
509 		nfbno1 = rbno + rlen;
510 		nflen1 = flen - rlen;
511 		nfbno2 = NULLAGBLOCK;
512 	} else if (rbno + rlen == fbno + flen) {
513 		nfbno1 = fbno;
514 		nflen1 = flen - rlen;
515 		nfbno2 = NULLAGBLOCK;
516 	} else {
517 		nfbno1 = fbno;
518 		nflen1 = rbno - fbno;
519 		nfbno2 = rbno + rlen;
520 		nflen2 = (fbno + flen) - nfbno2;
521 	}
522 	/*
523 	 * Delete the entry from the by-size btree.
524 	 */
525 	if ((error = xfs_btree_delete(cnt_cur, &i)))
526 		return error;
527 	if (XFS_IS_CORRUPT(mp, i != 1))
528 		return -EFSCORRUPTED;
529 	/*
530 	 * Add new by-size btree entry(s).
531 	 */
532 	if (nfbno1 != NULLAGBLOCK) {
533 		if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno1, nflen1, &i)))
534 			return error;
535 		if (XFS_IS_CORRUPT(mp, i != 0))
536 			return -EFSCORRUPTED;
537 		if ((error = xfs_btree_insert(cnt_cur, &i)))
538 			return error;
539 		if (XFS_IS_CORRUPT(mp, i != 1))
540 			return -EFSCORRUPTED;
541 	}
542 	if (nfbno2 != NULLAGBLOCK) {
543 		if ((error = xfs_alloc_lookup_eq(cnt_cur, nfbno2, nflen2, &i)))
544 			return error;
545 		if (XFS_IS_CORRUPT(mp, i != 0))
546 			return -EFSCORRUPTED;
547 		if ((error = xfs_btree_insert(cnt_cur, &i)))
548 			return error;
549 		if (XFS_IS_CORRUPT(mp, i != 1))
550 			return -EFSCORRUPTED;
551 	}
552 	/*
553 	 * Fix up the by-block btree entry(s).
554 	 */
555 	if (nfbno1 == NULLAGBLOCK) {
556 		/*
557 		 * No remaining freespace, just delete the by-block tree entry.
558 		 */
559 		if ((error = xfs_btree_delete(bno_cur, &i)))
560 			return error;
561 		if (XFS_IS_CORRUPT(mp, i != 1))
562 			return -EFSCORRUPTED;
563 	} else {
564 		/*
565 		 * Update the by-block entry to start later|be shorter.
566 		 */
567 		if ((error = xfs_alloc_update(bno_cur, nfbno1, nflen1)))
568 			return error;
569 	}
570 	if (nfbno2 != NULLAGBLOCK) {
571 		/*
572 		 * 2 resulting free entries, need to add one.
573 		 */
574 		if ((error = xfs_alloc_lookup_eq(bno_cur, nfbno2, nflen2, &i)))
575 			return error;
576 		if (XFS_IS_CORRUPT(mp, i != 0))
577 			return -EFSCORRUPTED;
578 		if ((error = xfs_btree_insert(bno_cur, &i)))
579 			return error;
580 		if (XFS_IS_CORRUPT(mp, i != 1))
581 			return -EFSCORRUPTED;
582 	}
583 	return 0;
584 }
585 
586 static xfs_failaddr_t
xfs_agfl_verify(struct xfs_buf * bp)587 xfs_agfl_verify(
588 	struct xfs_buf	*bp)
589 {
590 	struct xfs_mount *mp = bp->b_mount;
591 	struct xfs_agfl	*agfl = XFS_BUF_TO_AGFL(bp);
592 	__be32		*agfl_bno = xfs_buf_to_agfl_bno(bp);
593 	int		i;
594 
595 	/*
596 	 * There is no verification of non-crc AGFLs because mkfs does not
597 	 * initialise the AGFL to zero or NULL. Hence the only valid part of the
598 	 * AGFL is what the AGF says is active. We can't get to the AGF, so we
599 	 * can't verify just those entries are valid.
600 	 */
601 	if (!xfs_sb_version_hascrc(&mp->m_sb))
602 		return NULL;
603 
604 	if (!xfs_verify_magic(bp, agfl->agfl_magicnum))
605 		return __this_address;
606 	if (!uuid_equal(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid))
607 		return __this_address;
608 	/*
609 	 * during growfs operations, the perag is not fully initialised,
610 	 * so we can't use it for any useful checking. growfs ensures we can't
611 	 * use it by using uncached buffers that don't have the perag attached
612 	 * so we can detect and avoid this problem.
613 	 */
614 	if (bp->b_pag && be32_to_cpu(agfl->agfl_seqno) != bp->b_pag->pag_agno)
615 		return __this_address;
616 
617 	for (i = 0; i < xfs_agfl_size(mp); i++) {
618 		if (be32_to_cpu(agfl_bno[i]) != NULLAGBLOCK &&
619 		    be32_to_cpu(agfl_bno[i]) >= mp->m_sb.sb_agblocks)
620 			return __this_address;
621 	}
622 
623 	if (!xfs_log_check_lsn(mp, be64_to_cpu(XFS_BUF_TO_AGFL(bp)->agfl_lsn)))
624 		return __this_address;
625 	return NULL;
626 }
627 
628 static void
xfs_agfl_read_verify(struct xfs_buf * bp)629 xfs_agfl_read_verify(
630 	struct xfs_buf	*bp)
631 {
632 	struct xfs_mount *mp = bp->b_mount;
633 	xfs_failaddr_t	fa;
634 
635 	/*
636 	 * There is no verification of non-crc AGFLs because mkfs does not
637 	 * initialise the AGFL to zero or NULL. Hence the only valid part of the
638 	 * AGFL is what the AGF says is active. We can't get to the AGF, so we
639 	 * can't verify just those entries are valid.
640 	 */
641 	if (!xfs_sb_version_hascrc(&mp->m_sb))
642 		return;
643 
644 	if (!xfs_buf_verify_cksum(bp, XFS_AGFL_CRC_OFF))
645 		xfs_verifier_error(bp, -EFSBADCRC, __this_address);
646 	else {
647 		fa = xfs_agfl_verify(bp);
648 		if (fa)
649 			xfs_verifier_error(bp, -EFSCORRUPTED, fa);
650 	}
651 }
652 
653 static void
xfs_agfl_write_verify(struct xfs_buf * bp)654 xfs_agfl_write_verify(
655 	struct xfs_buf	*bp)
656 {
657 	struct xfs_mount	*mp = bp->b_mount;
658 	struct xfs_buf_log_item	*bip = bp->b_log_item;
659 	xfs_failaddr_t		fa;
660 
661 	/* no verification of non-crc AGFLs */
662 	if (!xfs_sb_version_hascrc(&mp->m_sb))
663 		return;
664 
665 	fa = xfs_agfl_verify(bp);
666 	if (fa) {
667 		xfs_verifier_error(bp, -EFSCORRUPTED, fa);
668 		return;
669 	}
670 
671 	if (bip)
672 		XFS_BUF_TO_AGFL(bp)->agfl_lsn = cpu_to_be64(bip->bli_item.li_lsn);
673 
674 	xfs_buf_update_cksum(bp, XFS_AGFL_CRC_OFF);
675 }
676 
677 const struct xfs_buf_ops xfs_agfl_buf_ops = {
678 	.name = "xfs_agfl",
679 	.magic = { cpu_to_be32(XFS_AGFL_MAGIC), cpu_to_be32(XFS_AGFL_MAGIC) },
680 	.verify_read = xfs_agfl_read_verify,
681 	.verify_write = xfs_agfl_write_verify,
682 	.verify_struct = xfs_agfl_verify,
683 };
684 
685 /*
686  * Read in the allocation group free block array.
687  */
688 int					/* error */
xfs_alloc_read_agfl(xfs_mount_t * mp,xfs_trans_t * tp,xfs_agnumber_t agno,xfs_buf_t ** bpp)689 xfs_alloc_read_agfl(
690 	xfs_mount_t	*mp,		/* mount point structure */
691 	xfs_trans_t	*tp,		/* transaction pointer */
692 	xfs_agnumber_t	agno,		/* allocation group number */
693 	xfs_buf_t	**bpp)		/* buffer for the ag free block array */
694 {
695 	xfs_buf_t	*bp;		/* return value */
696 	int		error;
697 
698 	ASSERT(agno != NULLAGNUMBER);
699 	error = xfs_trans_read_buf(
700 			mp, tp, mp->m_ddev_targp,
701 			XFS_AG_DADDR(mp, agno, XFS_AGFL_DADDR(mp)),
702 			XFS_FSS_TO_BB(mp, 1), 0, &bp, &xfs_agfl_buf_ops);
703 	if (error)
704 		return error;
705 	xfs_buf_set_ref(bp, XFS_AGFL_REF);
706 	*bpp = bp;
707 	return 0;
708 }
709 
710 STATIC int
xfs_alloc_update_counters(struct xfs_trans * tp,struct xfs_buf * agbp,long len)711 xfs_alloc_update_counters(
712 	struct xfs_trans	*tp,
713 	struct xfs_buf		*agbp,
714 	long			len)
715 {
716 	struct xfs_agf		*agf = agbp->b_addr;
717 
718 	agbp->b_pag->pagf_freeblks += len;
719 	be32_add_cpu(&agf->agf_freeblks, len);
720 
721 	xfs_trans_agblocks_delta(tp, len);
722 	if (unlikely(be32_to_cpu(agf->agf_freeblks) >
723 		     be32_to_cpu(agf->agf_length))) {
724 		xfs_buf_mark_corrupt(agbp);
725 		return -EFSCORRUPTED;
726 	}
727 
728 	xfs_alloc_log_agf(tp, agbp, XFS_AGF_FREEBLKS);
729 	return 0;
730 }
731 
732 /*
733  * Block allocation algorithm and data structures.
734  */
735 struct xfs_alloc_cur {
736 	struct xfs_btree_cur		*cnt;	/* btree cursors */
737 	struct xfs_btree_cur		*bnolt;
738 	struct xfs_btree_cur		*bnogt;
739 	xfs_extlen_t			cur_len;/* current search length */
740 	xfs_agblock_t			rec_bno;/* extent startblock */
741 	xfs_extlen_t			rec_len;/* extent length */
742 	xfs_agblock_t			bno;	/* alloc bno */
743 	xfs_extlen_t			len;	/* alloc len */
744 	xfs_extlen_t			diff;	/* diff from search bno */
745 	unsigned int			busy_gen;/* busy state */
746 	bool				busy;
747 };
748 
749 /*
750  * Set up cursors, etc. in the extent allocation cursor. This function can be
751  * called multiple times to reset an initialized structure without having to
752  * reallocate cursors.
753  */
754 static int
xfs_alloc_cur_setup(struct xfs_alloc_arg * args,struct xfs_alloc_cur * acur)755 xfs_alloc_cur_setup(
756 	struct xfs_alloc_arg	*args,
757 	struct xfs_alloc_cur	*acur)
758 {
759 	int			error;
760 	int			i;
761 
762 	ASSERT(args->alignment == 1 || args->type != XFS_ALLOCTYPE_THIS_BNO);
763 
764 	acur->cur_len = args->maxlen;
765 	acur->rec_bno = 0;
766 	acur->rec_len = 0;
767 	acur->bno = 0;
768 	acur->len = 0;
769 	acur->diff = -1;
770 	acur->busy = false;
771 	acur->busy_gen = 0;
772 
773 	/*
774 	 * Perform an initial cntbt lookup to check for availability of maxlen
775 	 * extents. If this fails, we'll return -ENOSPC to signal the caller to
776 	 * attempt a small allocation.
777 	 */
778 	if (!acur->cnt)
779 		acur->cnt = xfs_allocbt_init_cursor(args->mp, args->tp,
780 					args->agbp, args->agno, XFS_BTNUM_CNT);
781 	error = xfs_alloc_lookup_ge(acur->cnt, 0, args->maxlen, &i);
782 	if (error)
783 		return error;
784 
785 	/*
786 	 * Allocate the bnobt left and right search cursors.
787 	 */
788 	if (!acur->bnolt)
789 		acur->bnolt = xfs_allocbt_init_cursor(args->mp, args->tp,
790 					args->agbp, args->agno, XFS_BTNUM_BNO);
791 	if (!acur->bnogt)
792 		acur->bnogt = xfs_allocbt_init_cursor(args->mp, args->tp,
793 					args->agbp, args->agno, XFS_BTNUM_BNO);
794 	return i == 1 ? 0 : -ENOSPC;
795 }
796 
797 static void
xfs_alloc_cur_close(struct xfs_alloc_cur * acur,bool error)798 xfs_alloc_cur_close(
799 	struct xfs_alloc_cur	*acur,
800 	bool			error)
801 {
802 	int			cur_error = XFS_BTREE_NOERROR;
803 
804 	if (error)
805 		cur_error = XFS_BTREE_ERROR;
806 
807 	if (acur->cnt)
808 		xfs_btree_del_cursor(acur->cnt, cur_error);
809 	if (acur->bnolt)
810 		xfs_btree_del_cursor(acur->bnolt, cur_error);
811 	if (acur->bnogt)
812 		xfs_btree_del_cursor(acur->bnogt, cur_error);
813 	acur->cnt = acur->bnolt = acur->bnogt = NULL;
814 }
815 
816 /*
817  * Check an extent for allocation and track the best available candidate in the
818  * allocation structure. The cursor is deactivated if it has entered an out of
819  * range state based on allocation arguments. Optionally return the extent
820  * extent geometry and allocation status if requested by the caller.
821  */
822 static int
xfs_alloc_cur_check(struct xfs_alloc_arg * args,struct xfs_alloc_cur * acur,struct xfs_btree_cur * cur,int * new)823 xfs_alloc_cur_check(
824 	struct xfs_alloc_arg	*args,
825 	struct xfs_alloc_cur	*acur,
826 	struct xfs_btree_cur	*cur,
827 	int			*new)
828 {
829 	int			error, i;
830 	xfs_agblock_t		bno, bnoa, bnew;
831 	xfs_extlen_t		len, lena, diff = -1;
832 	bool			busy;
833 	unsigned		busy_gen = 0;
834 	bool			deactivate = false;
835 	bool			isbnobt = cur->bc_btnum == XFS_BTNUM_BNO;
836 
837 	*new = 0;
838 
839 	error = xfs_alloc_get_rec(cur, &bno, &len, &i);
840 	if (error)
841 		return error;
842 	if (XFS_IS_CORRUPT(args->mp, i != 1))
843 		return -EFSCORRUPTED;
844 
845 	/*
846 	 * Check minlen and deactivate a cntbt cursor if out of acceptable size
847 	 * range (i.e., walking backwards looking for a minlen extent).
848 	 */
849 	if (len < args->minlen) {
850 		deactivate = !isbnobt;
851 		goto out;
852 	}
853 
854 	busy = xfs_alloc_compute_aligned(args, bno, len, &bnoa, &lena,
855 					 &busy_gen);
856 	acur->busy |= busy;
857 	if (busy)
858 		acur->busy_gen = busy_gen;
859 	/* deactivate a bnobt cursor outside of locality range */
860 	if (bnoa < args->min_agbno || bnoa > args->max_agbno) {
861 		deactivate = isbnobt;
862 		goto out;
863 	}
864 	if (lena < args->minlen)
865 		goto out;
866 
867 	args->len = XFS_EXTLEN_MIN(lena, args->maxlen);
868 	xfs_alloc_fix_len(args);
869 	ASSERT(args->len >= args->minlen);
870 	if (args->len < acur->len)
871 		goto out;
872 
873 	/*
874 	 * We have an aligned record that satisfies minlen and beats or matches
875 	 * the candidate extent size. Compare locality for near allocation mode.
876 	 */
877 	ASSERT(args->type == XFS_ALLOCTYPE_NEAR_BNO);
878 	diff = xfs_alloc_compute_diff(args->agbno, args->len,
879 				      args->alignment, args->datatype,
880 				      bnoa, lena, &bnew);
881 	if (bnew == NULLAGBLOCK)
882 		goto out;
883 
884 	/*
885 	 * Deactivate a bnobt cursor with worse locality than the current best.
886 	 */
887 	if (diff > acur->diff) {
888 		deactivate = isbnobt;
889 		goto out;
890 	}
891 
892 	ASSERT(args->len > acur->len ||
893 	       (args->len == acur->len && diff <= acur->diff));
894 	acur->rec_bno = bno;
895 	acur->rec_len = len;
896 	acur->bno = bnew;
897 	acur->len = args->len;
898 	acur->diff = diff;
899 	*new = 1;
900 
901 	/*
902 	 * We're done if we found a perfect allocation. This only deactivates
903 	 * the current cursor, but this is just an optimization to terminate a
904 	 * cntbt search that otherwise runs to the edge of the tree.
905 	 */
906 	if (acur->diff == 0 && acur->len == args->maxlen)
907 		deactivate = true;
908 out:
909 	if (deactivate)
910 		cur->bc_ag.abt.active = false;
911 	trace_xfs_alloc_cur_check(args->mp, cur->bc_btnum, bno, len, diff,
912 				  *new);
913 	return 0;
914 }
915 
916 /*
917  * Complete an allocation of a candidate extent. Remove the extent from both
918  * trees and update the args structure.
919  */
920 STATIC int
xfs_alloc_cur_finish(struct xfs_alloc_arg * args,struct xfs_alloc_cur * acur)921 xfs_alloc_cur_finish(
922 	struct xfs_alloc_arg	*args,
923 	struct xfs_alloc_cur	*acur)
924 {
925 	struct xfs_agf __maybe_unused *agf = args->agbp->b_addr;
926 	int			error;
927 
928 	ASSERT(acur->cnt && acur->bnolt);
929 	ASSERT(acur->bno >= acur->rec_bno);
930 	ASSERT(acur->bno + acur->len <= acur->rec_bno + acur->rec_len);
931 	ASSERT(acur->rec_bno + acur->rec_len <= be32_to_cpu(agf->agf_length));
932 
933 	error = xfs_alloc_fixup_trees(acur->cnt, acur->bnolt, acur->rec_bno,
934 				      acur->rec_len, acur->bno, acur->len, 0);
935 	if (error)
936 		return error;
937 
938 	args->agbno = acur->bno;
939 	args->len = acur->len;
940 	args->wasfromfl = 0;
941 
942 	trace_xfs_alloc_cur(args);
943 	return 0;
944 }
945 
946 /*
947  * Locality allocation lookup algorithm. This expects a cntbt cursor and uses
948  * bno optimized lookup to search for extents with ideal size and locality.
949  */
950 STATIC int
xfs_alloc_cntbt_iter(struct xfs_alloc_arg * args,struct xfs_alloc_cur * acur)951 xfs_alloc_cntbt_iter(
952 	struct xfs_alloc_arg		*args,
953 	struct xfs_alloc_cur		*acur)
954 {
955 	struct xfs_btree_cur	*cur = acur->cnt;
956 	xfs_agblock_t		bno;
957 	xfs_extlen_t		len, cur_len;
958 	int			error;
959 	int			i;
960 
961 	if (!xfs_alloc_cur_active(cur))
962 		return 0;
963 
964 	/* locality optimized lookup */
965 	cur_len = acur->cur_len;
966 	error = xfs_alloc_lookup_ge(cur, args->agbno, cur_len, &i);
967 	if (error)
968 		return error;
969 	if (i == 0)
970 		return 0;
971 	error = xfs_alloc_get_rec(cur, &bno, &len, &i);
972 	if (error)
973 		return error;
974 
975 	/* check the current record and update search length from it */
976 	error = xfs_alloc_cur_check(args, acur, cur, &i);
977 	if (error)
978 		return error;
979 	ASSERT(len >= acur->cur_len);
980 	acur->cur_len = len;
981 
982 	/*
983 	 * We looked up the first record >= [agbno, len] above. The agbno is a
984 	 * secondary key and so the current record may lie just before or after
985 	 * agbno. If it is past agbno, check the previous record too so long as
986 	 * the length matches as it may be closer. Don't check a smaller record
987 	 * because that could deactivate our cursor.
988 	 */
989 	if (bno > args->agbno) {
990 		error = xfs_btree_decrement(cur, 0, &i);
991 		if (!error && i) {
992 			error = xfs_alloc_get_rec(cur, &bno, &len, &i);
993 			if (!error && i && len == acur->cur_len)
994 				error = xfs_alloc_cur_check(args, acur, cur,
995 							    &i);
996 		}
997 		if (error)
998 			return error;
999 	}
1000 
1001 	/*
1002 	 * Increment the search key until we find at least one allocation
1003 	 * candidate or if the extent we found was larger. Otherwise, double the
1004 	 * search key to optimize the search. Efficiency is more important here
1005 	 * than absolute best locality.
1006 	 */
1007 	cur_len <<= 1;
1008 	if (!acur->len || acur->cur_len >= cur_len)
1009 		acur->cur_len++;
1010 	else
1011 		acur->cur_len = cur_len;
1012 
1013 	return error;
1014 }
1015 
1016 /*
1017  * Deal with the case where only small freespaces remain. Either return the
1018  * contents of the last freespace record, or allocate space from the freelist if
1019  * there is nothing in the tree.
1020  */
1021 STATIC int			/* error */
xfs_alloc_ag_vextent_small(struct xfs_alloc_arg * args,struct xfs_btree_cur * ccur,xfs_agblock_t * fbnop,xfs_extlen_t * flenp,int * stat)1022 xfs_alloc_ag_vextent_small(
1023 	struct xfs_alloc_arg	*args,	/* allocation argument structure */
1024 	struct xfs_btree_cur	*ccur,	/* optional by-size cursor */
1025 	xfs_agblock_t		*fbnop,	/* result block number */
1026 	xfs_extlen_t		*flenp,	/* result length */
1027 	int			*stat)	/* status: 0-freelist, 1-normal/none */
1028 {
1029 	struct xfs_agf		*agf = args->agbp->b_addr;
1030 	int			error = 0;
1031 	xfs_agblock_t		fbno = NULLAGBLOCK;
1032 	xfs_extlen_t		flen = 0;
1033 	int			i = 0;
1034 
1035 	/*
1036 	 * If a cntbt cursor is provided, try to allocate the largest record in
1037 	 * the tree. Try the AGFL if the cntbt is empty, otherwise fail the
1038 	 * allocation. Make sure to respect minleft even when pulling from the
1039 	 * freelist.
1040 	 */
1041 	if (ccur)
1042 		error = xfs_btree_decrement(ccur, 0, &i);
1043 	if (error)
1044 		goto error;
1045 	if (i) {
1046 		error = xfs_alloc_get_rec(ccur, &fbno, &flen, &i);
1047 		if (error)
1048 			goto error;
1049 		if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1050 			error = -EFSCORRUPTED;
1051 			goto error;
1052 		}
1053 		goto out;
1054 	}
1055 
1056 	if (args->minlen != 1 || args->alignment != 1 ||
1057 	    args->resv == XFS_AG_RESV_AGFL ||
1058 	    be32_to_cpu(agf->agf_flcount) <= args->minleft)
1059 		goto out;
1060 
1061 	error = xfs_alloc_get_freelist(args->tp, args->agbp, &fbno, 0);
1062 	if (error)
1063 		goto error;
1064 	if (fbno == NULLAGBLOCK)
1065 		goto out;
1066 
1067 	xfs_extent_busy_reuse(args->mp, args->agno, fbno, 1,
1068 			      (args->datatype & XFS_ALLOC_NOBUSY));
1069 
1070 	if (args->datatype & XFS_ALLOC_USERDATA) {
1071 		struct xfs_buf	*bp;
1072 
1073 		error = xfs_trans_get_buf(args->tp, args->mp->m_ddev_targp,
1074 				XFS_AGB_TO_DADDR(args->mp, args->agno, fbno),
1075 				args->mp->m_bsize, 0, &bp);
1076 		if (error)
1077 			goto error;
1078 		xfs_trans_binval(args->tp, bp);
1079 	}
1080 	*fbnop = args->agbno = fbno;
1081 	*flenp = args->len = 1;
1082 	if (XFS_IS_CORRUPT(args->mp, fbno >= be32_to_cpu(agf->agf_length))) {
1083 		error = -EFSCORRUPTED;
1084 		goto error;
1085 	}
1086 	args->wasfromfl = 1;
1087 	trace_xfs_alloc_small_freelist(args);
1088 
1089 	/*
1090 	 * If we're feeding an AGFL block to something that doesn't live in the
1091 	 * free space, we need to clear out the OWN_AG rmap.
1092 	 */
1093 	error = xfs_rmap_free(args->tp, args->agbp, args->agno, fbno, 1,
1094 			      &XFS_RMAP_OINFO_AG);
1095 	if (error)
1096 		goto error;
1097 
1098 	*stat = 0;
1099 	return 0;
1100 
1101 out:
1102 	/*
1103 	 * Can't do the allocation, give up.
1104 	 */
1105 	if (flen < args->minlen) {
1106 		args->agbno = NULLAGBLOCK;
1107 		trace_xfs_alloc_small_notenough(args);
1108 		flen = 0;
1109 	}
1110 	*fbnop = fbno;
1111 	*flenp = flen;
1112 	*stat = 1;
1113 	trace_xfs_alloc_small_done(args);
1114 	return 0;
1115 
1116 error:
1117 	trace_xfs_alloc_small_error(args);
1118 	return error;
1119 }
1120 
1121 /*
1122  * Allocate a variable extent in the allocation group agno.
1123  * Type and bno are used to determine where in the allocation group the
1124  * extent will start.
1125  * Extent's length (returned in *len) will be between minlen and maxlen,
1126  * and of the form k * prod + mod unless there's nothing that large.
1127  * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
1128  */
1129 STATIC int			/* error */
xfs_alloc_ag_vextent(xfs_alloc_arg_t * args)1130 xfs_alloc_ag_vextent(
1131 	xfs_alloc_arg_t	*args)	/* argument structure for allocation */
1132 {
1133 	int		error=0;
1134 
1135 	ASSERT(args->minlen > 0);
1136 	ASSERT(args->maxlen > 0);
1137 	ASSERT(args->minlen <= args->maxlen);
1138 	ASSERT(args->mod < args->prod);
1139 	ASSERT(args->alignment > 0);
1140 
1141 	/*
1142 	 * Branch to correct routine based on the type.
1143 	 */
1144 	args->wasfromfl = 0;
1145 	switch (args->type) {
1146 	case XFS_ALLOCTYPE_THIS_AG:
1147 		error = xfs_alloc_ag_vextent_size(args);
1148 		break;
1149 	case XFS_ALLOCTYPE_NEAR_BNO:
1150 		error = xfs_alloc_ag_vextent_near(args);
1151 		break;
1152 	case XFS_ALLOCTYPE_THIS_BNO:
1153 		error = xfs_alloc_ag_vextent_exact(args);
1154 		break;
1155 	default:
1156 		ASSERT(0);
1157 		/* NOTREACHED */
1158 	}
1159 
1160 	if (error || args->agbno == NULLAGBLOCK)
1161 		return error;
1162 
1163 	ASSERT(args->len >= args->minlen);
1164 	ASSERT(args->len <= args->maxlen);
1165 	ASSERT(!args->wasfromfl || args->resv != XFS_AG_RESV_AGFL);
1166 	ASSERT(args->agbno % args->alignment == 0);
1167 
1168 	/* if not file data, insert new block into the reverse map btree */
1169 	if (!xfs_rmap_should_skip_owner_update(&args->oinfo)) {
1170 		error = xfs_rmap_alloc(args->tp, args->agbp, args->agno,
1171 				       args->agbno, args->len, &args->oinfo);
1172 		if (error)
1173 			return error;
1174 	}
1175 
1176 	if (!args->wasfromfl) {
1177 		error = xfs_alloc_update_counters(args->tp, args->agbp,
1178 						  -((long)(args->len)));
1179 		if (error)
1180 			return error;
1181 
1182 		ASSERT(!xfs_extent_busy_search(args->mp, args->agno,
1183 					      args->agbno, args->len));
1184 	}
1185 
1186 	xfs_ag_resv_alloc_extent(args->pag, args->resv, args);
1187 
1188 	XFS_STATS_INC(args->mp, xs_allocx);
1189 	XFS_STATS_ADD(args->mp, xs_allocb, args->len);
1190 	return error;
1191 }
1192 
1193 /*
1194  * Allocate a variable extent at exactly agno/bno.
1195  * Extent's length (returned in *len) will be between minlen and maxlen,
1196  * and of the form k * prod + mod unless there's nothing that large.
1197  * Return the starting a.g. block (bno), or NULLAGBLOCK if we can't do it.
1198  */
1199 STATIC int			/* error */
xfs_alloc_ag_vextent_exact(xfs_alloc_arg_t * args)1200 xfs_alloc_ag_vextent_exact(
1201 	xfs_alloc_arg_t	*args)	/* allocation argument structure */
1202 {
1203 	struct xfs_agf __maybe_unused *agf = args->agbp->b_addr;
1204 	xfs_btree_cur_t	*bno_cur;/* by block-number btree cursor */
1205 	xfs_btree_cur_t	*cnt_cur;/* by count btree cursor */
1206 	int		error;
1207 	xfs_agblock_t	fbno;	/* start block of found extent */
1208 	xfs_extlen_t	flen;	/* length of found extent */
1209 	xfs_agblock_t	tbno;	/* start block of busy extent */
1210 	xfs_extlen_t	tlen;	/* length of busy extent */
1211 	xfs_agblock_t	tend;	/* end block of busy extent */
1212 	int		i;	/* success/failure of operation */
1213 	unsigned	busy_gen;
1214 
1215 	ASSERT(args->alignment == 1);
1216 
1217 	/*
1218 	 * Allocate/initialize a cursor for the by-number freespace btree.
1219 	 */
1220 	bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1221 					  args->agno, XFS_BTNUM_BNO);
1222 
1223 	/*
1224 	 * Lookup bno and minlen in the btree (minlen is irrelevant, really).
1225 	 * Look for the closest free block <= bno, it must contain bno
1226 	 * if any free block does.
1227 	 */
1228 	error = xfs_alloc_lookup_le(bno_cur, args->agbno, args->minlen, &i);
1229 	if (error)
1230 		goto error0;
1231 	if (!i)
1232 		goto not_found;
1233 
1234 	/*
1235 	 * Grab the freespace record.
1236 	 */
1237 	error = xfs_alloc_get_rec(bno_cur, &fbno, &flen, &i);
1238 	if (error)
1239 		goto error0;
1240 	if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1241 		error = -EFSCORRUPTED;
1242 		goto error0;
1243 	}
1244 	ASSERT(fbno <= args->agbno);
1245 
1246 	/*
1247 	 * Check for overlapping busy extents.
1248 	 */
1249 	tbno = fbno;
1250 	tlen = flen;
1251 	xfs_extent_busy_trim(args, &tbno, &tlen, &busy_gen);
1252 
1253 	/*
1254 	 * Give up if the start of the extent is busy, or the freespace isn't
1255 	 * long enough for the minimum request.
1256 	 */
1257 	if (tbno > args->agbno)
1258 		goto not_found;
1259 	if (tlen < args->minlen)
1260 		goto not_found;
1261 	tend = tbno + tlen;
1262 	if (tend < args->agbno + args->minlen)
1263 		goto not_found;
1264 
1265 	/*
1266 	 * End of extent will be smaller of the freespace end and the
1267 	 * maximal requested end.
1268 	 *
1269 	 * Fix the length according to mod and prod if given.
1270 	 */
1271 	args->len = XFS_AGBLOCK_MIN(tend, args->agbno + args->maxlen)
1272 						- args->agbno;
1273 	xfs_alloc_fix_len(args);
1274 	ASSERT(args->agbno + args->len <= tend);
1275 
1276 	/*
1277 	 * We are allocating agbno for args->len
1278 	 * Allocate/initialize a cursor for the by-size btree.
1279 	 */
1280 	cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1281 		args->agno, XFS_BTNUM_CNT);
1282 	ASSERT(args->agbno + args->len <= be32_to_cpu(agf->agf_length));
1283 	error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen, args->agbno,
1284 				      args->len, XFSA_FIXUP_BNO_OK);
1285 	if (error) {
1286 		xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1287 		goto error0;
1288 	}
1289 
1290 	xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1291 	xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1292 
1293 	args->wasfromfl = 0;
1294 	trace_xfs_alloc_exact_done(args);
1295 	return 0;
1296 
1297 not_found:
1298 	/* Didn't find it, return null. */
1299 	xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1300 	args->agbno = NULLAGBLOCK;
1301 	trace_xfs_alloc_exact_notfound(args);
1302 	return 0;
1303 
1304 error0:
1305 	xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
1306 	trace_xfs_alloc_exact_error(args);
1307 	return error;
1308 }
1309 
1310 /*
1311  * Search a given number of btree records in a given direction. Check each
1312  * record against the good extent we've already found.
1313  */
1314 STATIC int
xfs_alloc_walk_iter(struct xfs_alloc_arg * args,struct xfs_alloc_cur * acur,struct xfs_btree_cur * cur,bool increment,bool find_one,int count,int * stat)1315 xfs_alloc_walk_iter(
1316 	struct xfs_alloc_arg	*args,
1317 	struct xfs_alloc_cur	*acur,
1318 	struct xfs_btree_cur	*cur,
1319 	bool			increment,
1320 	bool			find_one, /* quit on first candidate */
1321 	int			count,    /* rec count (-1 for infinite) */
1322 	int			*stat)
1323 {
1324 	int			error;
1325 	int			i;
1326 
1327 	*stat = 0;
1328 
1329 	/*
1330 	 * Search so long as the cursor is active or we find a better extent.
1331 	 * The cursor is deactivated if it extends beyond the range of the
1332 	 * current allocation candidate.
1333 	 */
1334 	while (xfs_alloc_cur_active(cur) && count) {
1335 		error = xfs_alloc_cur_check(args, acur, cur, &i);
1336 		if (error)
1337 			return error;
1338 		if (i == 1) {
1339 			*stat = 1;
1340 			if (find_one)
1341 				break;
1342 		}
1343 		if (!xfs_alloc_cur_active(cur))
1344 			break;
1345 
1346 		if (increment)
1347 			error = xfs_btree_increment(cur, 0, &i);
1348 		else
1349 			error = xfs_btree_decrement(cur, 0, &i);
1350 		if (error)
1351 			return error;
1352 		if (i == 0)
1353 			cur->bc_ag.abt.active = false;
1354 
1355 		if (count > 0)
1356 			count--;
1357 	}
1358 
1359 	return 0;
1360 }
1361 
1362 /*
1363  * Search the by-bno and by-size btrees in parallel in search of an extent with
1364  * ideal locality based on the NEAR mode ->agbno locality hint.
1365  */
1366 STATIC int
xfs_alloc_ag_vextent_locality(struct xfs_alloc_arg * args,struct xfs_alloc_cur * acur,int * stat)1367 xfs_alloc_ag_vextent_locality(
1368 	struct xfs_alloc_arg	*args,
1369 	struct xfs_alloc_cur	*acur,
1370 	int			*stat)
1371 {
1372 	struct xfs_btree_cur	*fbcur = NULL;
1373 	int			error;
1374 	int			i;
1375 	bool			fbinc;
1376 
1377 	ASSERT(acur->len == 0);
1378 	ASSERT(args->type == XFS_ALLOCTYPE_NEAR_BNO);
1379 
1380 	*stat = 0;
1381 
1382 	error = xfs_alloc_lookup_ge(acur->cnt, args->agbno, acur->cur_len, &i);
1383 	if (error)
1384 		return error;
1385 	error = xfs_alloc_lookup_le(acur->bnolt, args->agbno, 0, &i);
1386 	if (error)
1387 		return error;
1388 	error = xfs_alloc_lookup_ge(acur->bnogt, args->agbno, 0, &i);
1389 	if (error)
1390 		return error;
1391 
1392 	/*
1393 	 * Search the bnobt and cntbt in parallel. Search the bnobt left and
1394 	 * right and lookup the closest extent to the locality hint for each
1395 	 * extent size key in the cntbt. The entire search terminates
1396 	 * immediately on a bnobt hit because that means we've found best case
1397 	 * locality. Otherwise the search continues until the cntbt cursor runs
1398 	 * off the end of the tree. If no allocation candidate is found at this
1399 	 * point, give up on locality, walk backwards from the end of the cntbt
1400 	 * and take the first available extent.
1401 	 *
1402 	 * The parallel tree searches balance each other out to provide fairly
1403 	 * consistent performance for various situations. The bnobt search can
1404 	 * have pathological behavior in the worst case scenario of larger
1405 	 * allocation requests and fragmented free space. On the other hand, the
1406 	 * bnobt is able to satisfy most smaller allocation requests much more
1407 	 * quickly than the cntbt. The cntbt search can sift through fragmented
1408 	 * free space and sets of free extents for larger allocation requests
1409 	 * more quickly than the bnobt. Since the locality hint is just a hint
1410 	 * and we don't want to scan the entire bnobt for perfect locality, the
1411 	 * cntbt search essentially bounds the bnobt search such that we can
1412 	 * find good enough locality at reasonable performance in most cases.
1413 	 */
1414 	while (xfs_alloc_cur_active(acur->bnolt) ||
1415 	       xfs_alloc_cur_active(acur->bnogt) ||
1416 	       xfs_alloc_cur_active(acur->cnt)) {
1417 
1418 		trace_xfs_alloc_cur_lookup(args);
1419 
1420 		/*
1421 		 * Search the bnobt left and right. In the case of a hit, finish
1422 		 * the search in the opposite direction and we're done.
1423 		 */
1424 		error = xfs_alloc_walk_iter(args, acur, acur->bnolt, false,
1425 					    true, 1, &i);
1426 		if (error)
1427 			return error;
1428 		if (i == 1) {
1429 			trace_xfs_alloc_cur_left(args);
1430 			fbcur = acur->bnogt;
1431 			fbinc = true;
1432 			break;
1433 		}
1434 		error = xfs_alloc_walk_iter(args, acur, acur->bnogt, true, true,
1435 					    1, &i);
1436 		if (error)
1437 			return error;
1438 		if (i == 1) {
1439 			trace_xfs_alloc_cur_right(args);
1440 			fbcur = acur->bnolt;
1441 			fbinc = false;
1442 			break;
1443 		}
1444 
1445 		/*
1446 		 * Check the extent with best locality based on the current
1447 		 * extent size search key and keep track of the best candidate.
1448 		 */
1449 		error = xfs_alloc_cntbt_iter(args, acur);
1450 		if (error)
1451 			return error;
1452 		if (!xfs_alloc_cur_active(acur->cnt)) {
1453 			trace_xfs_alloc_cur_lookup_done(args);
1454 			break;
1455 		}
1456 	}
1457 
1458 	/*
1459 	 * If we failed to find anything due to busy extents, return empty
1460 	 * handed so the caller can flush and retry. If no busy extents were
1461 	 * found, walk backwards from the end of the cntbt as a last resort.
1462 	 */
1463 	if (!xfs_alloc_cur_active(acur->cnt) && !acur->len && !acur->busy) {
1464 		error = xfs_btree_decrement(acur->cnt, 0, &i);
1465 		if (error)
1466 			return error;
1467 		if (i) {
1468 			acur->cnt->bc_ag.abt.active = true;
1469 			fbcur = acur->cnt;
1470 			fbinc = false;
1471 		}
1472 	}
1473 
1474 	/*
1475 	 * Search in the opposite direction for a better entry in the case of
1476 	 * a bnobt hit or walk backwards from the end of the cntbt.
1477 	 */
1478 	if (fbcur) {
1479 		error = xfs_alloc_walk_iter(args, acur, fbcur, fbinc, true, -1,
1480 					    &i);
1481 		if (error)
1482 			return error;
1483 	}
1484 
1485 	if (acur->len)
1486 		*stat = 1;
1487 
1488 	return 0;
1489 }
1490 
1491 /* Check the last block of the cnt btree for allocations. */
1492 static int
xfs_alloc_ag_vextent_lastblock(struct xfs_alloc_arg * args,struct xfs_alloc_cur * acur,xfs_agblock_t * bno,xfs_extlen_t * len,bool * allocated)1493 xfs_alloc_ag_vextent_lastblock(
1494 	struct xfs_alloc_arg	*args,
1495 	struct xfs_alloc_cur	*acur,
1496 	xfs_agblock_t		*bno,
1497 	xfs_extlen_t		*len,
1498 	bool			*allocated)
1499 {
1500 	int			error;
1501 	int			i;
1502 
1503 #ifdef DEBUG
1504 	/* Randomly don't execute the first algorithm. */
1505 	if (prandom_u32() & 1)
1506 		return 0;
1507 #endif
1508 
1509 	/*
1510 	 * Start from the entry that lookup found, sequence through all larger
1511 	 * free blocks.  If we're actually pointing at a record smaller than
1512 	 * maxlen, go to the start of this block, and skip all those smaller
1513 	 * than minlen.
1514 	 */
1515 	if (*len || args->alignment > 1) {
1516 		acur->cnt->bc_ptrs[0] = 1;
1517 		do {
1518 			error = xfs_alloc_get_rec(acur->cnt, bno, len, &i);
1519 			if (error)
1520 				return error;
1521 			if (XFS_IS_CORRUPT(args->mp, i != 1))
1522 				return -EFSCORRUPTED;
1523 			if (*len >= args->minlen)
1524 				break;
1525 			error = xfs_btree_increment(acur->cnt, 0, &i);
1526 			if (error)
1527 				return error;
1528 		} while (i);
1529 		ASSERT(*len >= args->minlen);
1530 		if (!i)
1531 			return 0;
1532 	}
1533 
1534 	error = xfs_alloc_walk_iter(args, acur, acur->cnt, true, false, -1, &i);
1535 	if (error)
1536 		return error;
1537 
1538 	/*
1539 	 * It didn't work.  We COULD be in a case where there's a good record
1540 	 * somewhere, so try again.
1541 	 */
1542 	if (acur->len == 0)
1543 		return 0;
1544 
1545 	trace_xfs_alloc_near_first(args);
1546 	*allocated = true;
1547 	return 0;
1548 }
1549 
1550 /*
1551  * Allocate a variable extent near bno in the allocation group agno.
1552  * Extent's length (returned in len) will be between minlen and maxlen,
1553  * and of the form k * prod + mod unless there's nothing that large.
1554  * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
1555  */
1556 STATIC int
xfs_alloc_ag_vextent_near(struct xfs_alloc_arg * args)1557 xfs_alloc_ag_vextent_near(
1558 	struct xfs_alloc_arg	*args)
1559 {
1560 	struct xfs_alloc_cur	acur = {};
1561 	int			error;		/* error code */
1562 	int			i;		/* result code, temporary */
1563 	xfs_agblock_t		bno;
1564 	xfs_extlen_t		len;
1565 
1566 	/* handle uninitialized agbno range so caller doesn't have to */
1567 	if (!args->min_agbno && !args->max_agbno)
1568 		args->max_agbno = args->mp->m_sb.sb_agblocks - 1;
1569 	ASSERT(args->min_agbno <= args->max_agbno);
1570 
1571 	/* clamp agbno to the range if it's outside */
1572 	if (args->agbno < args->min_agbno)
1573 		args->agbno = args->min_agbno;
1574 	if (args->agbno > args->max_agbno)
1575 		args->agbno = args->max_agbno;
1576 
1577 restart:
1578 	len = 0;
1579 
1580 	/*
1581 	 * Set up cursors and see if there are any free extents as big as
1582 	 * maxlen. If not, pick the last entry in the tree unless the tree is
1583 	 * empty.
1584 	 */
1585 	error = xfs_alloc_cur_setup(args, &acur);
1586 	if (error == -ENOSPC) {
1587 		error = xfs_alloc_ag_vextent_small(args, acur.cnt, &bno,
1588 				&len, &i);
1589 		if (error)
1590 			goto out;
1591 		if (i == 0 || len == 0) {
1592 			trace_xfs_alloc_near_noentry(args);
1593 			goto out;
1594 		}
1595 		ASSERT(i == 1);
1596 	} else if (error) {
1597 		goto out;
1598 	}
1599 
1600 	/*
1601 	 * First algorithm.
1602 	 * If the requested extent is large wrt the freespaces available
1603 	 * in this a.g., then the cursor will be pointing to a btree entry
1604 	 * near the right edge of the tree.  If it's in the last btree leaf
1605 	 * block, then we just examine all the entries in that block
1606 	 * that are big enough, and pick the best one.
1607 	 */
1608 	if (xfs_btree_islastblock(acur.cnt, 0)) {
1609 		bool		allocated = false;
1610 
1611 		error = xfs_alloc_ag_vextent_lastblock(args, &acur, &bno, &len,
1612 				&allocated);
1613 		if (error)
1614 			goto out;
1615 		if (allocated)
1616 			goto alloc_finish;
1617 	}
1618 
1619 	/*
1620 	 * Second algorithm. Combined cntbt and bnobt search to find ideal
1621 	 * locality.
1622 	 */
1623 	error = xfs_alloc_ag_vextent_locality(args, &acur, &i);
1624 	if (error)
1625 		goto out;
1626 
1627 	/*
1628 	 * If we couldn't get anything, give up.
1629 	 */
1630 	if (!acur.len) {
1631 		if (acur.busy) {
1632 			trace_xfs_alloc_near_busy(args);
1633 			xfs_extent_busy_flush(args->mp, args->pag,
1634 					      acur.busy_gen);
1635 			goto restart;
1636 		}
1637 		trace_xfs_alloc_size_neither(args);
1638 		args->agbno = NULLAGBLOCK;
1639 		goto out;
1640 	}
1641 
1642 alloc_finish:
1643 	/* fix up btrees on a successful allocation */
1644 	error = xfs_alloc_cur_finish(args, &acur);
1645 
1646 out:
1647 	xfs_alloc_cur_close(&acur, error);
1648 	return error;
1649 }
1650 
1651 /*
1652  * Allocate a variable extent anywhere in the allocation group agno.
1653  * Extent's length (returned in len) will be between minlen and maxlen,
1654  * and of the form k * prod + mod unless there's nothing that large.
1655  * Return the starting a.g. block, or NULLAGBLOCK if we can't do it.
1656  */
1657 STATIC int				/* error */
xfs_alloc_ag_vextent_size(xfs_alloc_arg_t * args)1658 xfs_alloc_ag_vextent_size(
1659 	xfs_alloc_arg_t	*args)		/* allocation argument structure */
1660 {
1661 	struct xfs_agf	*agf = args->agbp->b_addr;
1662 	xfs_btree_cur_t	*bno_cur;	/* cursor for bno btree */
1663 	xfs_btree_cur_t	*cnt_cur;	/* cursor for cnt btree */
1664 	int		error;		/* error result */
1665 	xfs_agblock_t	fbno;		/* start of found freespace */
1666 	xfs_extlen_t	flen;		/* length of found freespace */
1667 	int		i;		/* temp status variable */
1668 	xfs_agblock_t	rbno;		/* returned block number */
1669 	xfs_extlen_t	rlen;		/* length of returned extent */
1670 	bool		busy;
1671 	unsigned	busy_gen;
1672 
1673 restart:
1674 	/*
1675 	 * Allocate and initialize a cursor for the by-size btree.
1676 	 */
1677 	cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1678 		args->agno, XFS_BTNUM_CNT);
1679 	bno_cur = NULL;
1680 	busy = false;
1681 
1682 	/*
1683 	 * Look for an entry >= maxlen+alignment-1 blocks.
1684 	 */
1685 	if ((error = xfs_alloc_lookup_ge(cnt_cur, 0,
1686 			args->maxlen + args->alignment - 1, &i)))
1687 		goto error0;
1688 
1689 	/*
1690 	 * If none then we have to settle for a smaller extent. In the case that
1691 	 * there are no large extents, this will return the last entry in the
1692 	 * tree unless the tree is empty. In the case that there are only busy
1693 	 * large extents, this will return the largest small extent unless there
1694 	 * are no smaller extents available.
1695 	 */
1696 	if (!i) {
1697 		error = xfs_alloc_ag_vextent_small(args, cnt_cur,
1698 						   &fbno, &flen, &i);
1699 		if (error)
1700 			goto error0;
1701 		if (i == 0 || flen == 0) {
1702 			xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1703 			trace_xfs_alloc_size_noentry(args);
1704 			return 0;
1705 		}
1706 		ASSERT(i == 1);
1707 		busy = xfs_alloc_compute_aligned(args, fbno, flen, &rbno,
1708 				&rlen, &busy_gen);
1709 	} else {
1710 		/*
1711 		 * Search for a non-busy extent that is large enough.
1712 		 */
1713 		for (;;) {
1714 			error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, &i);
1715 			if (error)
1716 				goto error0;
1717 			if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1718 				error = -EFSCORRUPTED;
1719 				goto error0;
1720 			}
1721 
1722 			busy = xfs_alloc_compute_aligned(args, fbno, flen,
1723 					&rbno, &rlen, &busy_gen);
1724 
1725 			if (rlen >= args->maxlen)
1726 				break;
1727 
1728 			error = xfs_btree_increment(cnt_cur, 0, &i);
1729 			if (error)
1730 				goto error0;
1731 			if (i == 0) {
1732 				/*
1733 				 * Our only valid extents must have been busy.
1734 				 * Make it unbusy by forcing the log out and
1735 				 * retrying.
1736 				 */
1737 				xfs_btree_del_cursor(cnt_cur,
1738 						     XFS_BTREE_NOERROR);
1739 				trace_xfs_alloc_size_busy(args);
1740 				xfs_extent_busy_flush(args->mp,
1741 							args->pag, busy_gen);
1742 				goto restart;
1743 			}
1744 		}
1745 	}
1746 
1747 	/*
1748 	 * In the first case above, we got the last entry in the
1749 	 * by-size btree.  Now we check to see if the space hits maxlen
1750 	 * once aligned; if not, we search left for something better.
1751 	 * This can't happen in the second case above.
1752 	 */
1753 	rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
1754 	if (XFS_IS_CORRUPT(args->mp,
1755 			   rlen != 0 &&
1756 			   (rlen > flen ||
1757 			    rbno + rlen > fbno + flen))) {
1758 		error = -EFSCORRUPTED;
1759 		goto error0;
1760 	}
1761 	if (rlen < args->maxlen) {
1762 		xfs_agblock_t	bestfbno;
1763 		xfs_extlen_t	bestflen;
1764 		xfs_agblock_t	bestrbno;
1765 		xfs_extlen_t	bestrlen;
1766 
1767 		bestrlen = rlen;
1768 		bestrbno = rbno;
1769 		bestflen = flen;
1770 		bestfbno = fbno;
1771 		for (;;) {
1772 			if ((error = xfs_btree_decrement(cnt_cur, 0, &i)))
1773 				goto error0;
1774 			if (i == 0)
1775 				break;
1776 			if ((error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen,
1777 					&i)))
1778 				goto error0;
1779 			if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1780 				error = -EFSCORRUPTED;
1781 				goto error0;
1782 			}
1783 			if (flen < bestrlen)
1784 				break;
1785 			busy = xfs_alloc_compute_aligned(args, fbno, flen,
1786 					&rbno, &rlen, &busy_gen);
1787 			rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
1788 			if (XFS_IS_CORRUPT(args->mp,
1789 					   rlen != 0 &&
1790 					   (rlen > flen ||
1791 					    rbno + rlen > fbno + flen))) {
1792 				error = -EFSCORRUPTED;
1793 				goto error0;
1794 			}
1795 			if (rlen > bestrlen) {
1796 				bestrlen = rlen;
1797 				bestrbno = rbno;
1798 				bestflen = flen;
1799 				bestfbno = fbno;
1800 				if (rlen == args->maxlen)
1801 					break;
1802 			}
1803 		}
1804 		if ((error = xfs_alloc_lookup_eq(cnt_cur, bestfbno, bestflen,
1805 				&i)))
1806 			goto error0;
1807 		if (XFS_IS_CORRUPT(args->mp, i != 1)) {
1808 			error = -EFSCORRUPTED;
1809 			goto error0;
1810 		}
1811 		rlen = bestrlen;
1812 		rbno = bestrbno;
1813 		flen = bestflen;
1814 		fbno = bestfbno;
1815 	}
1816 	args->wasfromfl = 0;
1817 	/*
1818 	 * Fix up the length.
1819 	 */
1820 	args->len = rlen;
1821 	if (rlen < args->minlen) {
1822 		if (busy) {
1823 			xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1824 			trace_xfs_alloc_size_busy(args);
1825 			xfs_extent_busy_flush(args->mp, args->pag, busy_gen);
1826 			goto restart;
1827 		}
1828 		goto out_nominleft;
1829 	}
1830 	xfs_alloc_fix_len(args);
1831 
1832 	rlen = args->len;
1833 	if (XFS_IS_CORRUPT(args->mp, rlen > flen)) {
1834 		error = -EFSCORRUPTED;
1835 		goto error0;
1836 	}
1837 	/*
1838 	 * Allocate and initialize a cursor for the by-block tree.
1839 	 */
1840 	bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
1841 		args->agno, XFS_BTNUM_BNO);
1842 	if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen,
1843 			rbno, rlen, XFSA_FIXUP_CNT_OK)))
1844 		goto error0;
1845 	xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1846 	xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
1847 	cnt_cur = bno_cur = NULL;
1848 	args->len = rlen;
1849 	args->agbno = rbno;
1850 	if (XFS_IS_CORRUPT(args->mp,
1851 			   args->agbno + args->len >
1852 			   be32_to_cpu(agf->agf_length))) {
1853 		error = -EFSCORRUPTED;
1854 		goto error0;
1855 	}
1856 	trace_xfs_alloc_size_done(args);
1857 	return 0;
1858 
1859 error0:
1860 	trace_xfs_alloc_size_error(args);
1861 	if (cnt_cur)
1862 		xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
1863 	if (bno_cur)
1864 		xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
1865 	return error;
1866 
1867 out_nominleft:
1868 	xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
1869 	trace_xfs_alloc_size_nominleft(args);
1870 	args->agbno = NULLAGBLOCK;
1871 	return 0;
1872 }
1873 
1874 /*
1875  * Free the extent starting at agno/bno for length.
1876  */
1877 STATIC int
xfs_free_ag_extent(struct xfs_trans * tp,struct xfs_buf * agbp,xfs_agnumber_t agno,xfs_agblock_t bno,xfs_extlen_t len,const struct xfs_owner_info * oinfo,enum xfs_ag_resv_type type)1878 xfs_free_ag_extent(
1879 	struct xfs_trans		*tp,
1880 	struct xfs_buf			*agbp,
1881 	xfs_agnumber_t			agno,
1882 	xfs_agblock_t			bno,
1883 	xfs_extlen_t			len,
1884 	const struct xfs_owner_info	*oinfo,
1885 	enum xfs_ag_resv_type		type)
1886 {
1887 	struct xfs_mount		*mp;
1888 	struct xfs_btree_cur		*bno_cur;
1889 	struct xfs_btree_cur		*cnt_cur;
1890 	xfs_agblock_t			gtbno; /* start of right neighbor */
1891 	xfs_extlen_t			gtlen; /* length of right neighbor */
1892 	xfs_agblock_t			ltbno; /* start of left neighbor */
1893 	xfs_extlen_t			ltlen; /* length of left neighbor */
1894 	xfs_agblock_t			nbno; /* new starting block of freesp */
1895 	xfs_extlen_t			nlen; /* new length of freespace */
1896 	int				haveleft; /* have a left neighbor */
1897 	int				haveright; /* have a right neighbor */
1898 	int				i;
1899 	int				error;
1900 
1901 	bno_cur = cnt_cur = NULL;
1902 	mp = tp->t_mountp;
1903 
1904 	if (!xfs_rmap_should_skip_owner_update(oinfo)) {
1905 		error = xfs_rmap_free(tp, agbp, agno, bno, len, oinfo);
1906 		if (error)
1907 			goto error0;
1908 	}
1909 
1910 	/*
1911 	 * Allocate and initialize a cursor for the by-block btree.
1912 	 */
1913 	bno_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_BNO);
1914 	/*
1915 	 * Look for a neighboring block on the left (lower block numbers)
1916 	 * that is contiguous with this space.
1917 	 */
1918 	if ((error = xfs_alloc_lookup_le(bno_cur, bno, len, &haveleft)))
1919 		goto error0;
1920 	if (haveleft) {
1921 		/*
1922 		 * There is a block to our left.
1923 		 */
1924 		if ((error = xfs_alloc_get_rec(bno_cur, &ltbno, &ltlen, &i)))
1925 			goto error0;
1926 		if (XFS_IS_CORRUPT(mp, i != 1)) {
1927 			error = -EFSCORRUPTED;
1928 			goto error0;
1929 		}
1930 		/*
1931 		 * It's not contiguous, though.
1932 		 */
1933 		if (ltbno + ltlen < bno)
1934 			haveleft = 0;
1935 		else {
1936 			/*
1937 			 * If this failure happens the request to free this
1938 			 * space was invalid, it's (partly) already free.
1939 			 * Very bad.
1940 			 */
1941 			if (XFS_IS_CORRUPT(mp, ltbno + ltlen > bno)) {
1942 				error = -EFSCORRUPTED;
1943 				goto error0;
1944 			}
1945 		}
1946 	}
1947 	/*
1948 	 * Look for a neighboring block on the right (higher block numbers)
1949 	 * that is contiguous with this space.
1950 	 */
1951 	if ((error = xfs_btree_increment(bno_cur, 0, &haveright)))
1952 		goto error0;
1953 	if (haveright) {
1954 		/*
1955 		 * There is a block to our right.
1956 		 */
1957 		if ((error = xfs_alloc_get_rec(bno_cur, &gtbno, &gtlen, &i)))
1958 			goto error0;
1959 		if (XFS_IS_CORRUPT(mp, i != 1)) {
1960 			error = -EFSCORRUPTED;
1961 			goto error0;
1962 		}
1963 		/*
1964 		 * It's not contiguous, though.
1965 		 */
1966 		if (bno + len < gtbno)
1967 			haveright = 0;
1968 		else {
1969 			/*
1970 			 * If this failure happens the request to free this
1971 			 * space was invalid, it's (partly) already free.
1972 			 * Very bad.
1973 			 */
1974 			if (XFS_IS_CORRUPT(mp, bno + len > gtbno)) {
1975 				error = -EFSCORRUPTED;
1976 				goto error0;
1977 			}
1978 		}
1979 	}
1980 	/*
1981 	 * Now allocate and initialize a cursor for the by-size tree.
1982 	 */
1983 	cnt_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_CNT);
1984 	/*
1985 	 * Have both left and right contiguous neighbors.
1986 	 * Merge all three into a single free block.
1987 	 */
1988 	if (haveleft && haveright) {
1989 		/*
1990 		 * Delete the old by-size entry on the left.
1991 		 */
1992 		if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i)))
1993 			goto error0;
1994 		if (XFS_IS_CORRUPT(mp, i != 1)) {
1995 			error = -EFSCORRUPTED;
1996 			goto error0;
1997 		}
1998 		if ((error = xfs_btree_delete(cnt_cur, &i)))
1999 			goto error0;
2000 		if (XFS_IS_CORRUPT(mp, i != 1)) {
2001 			error = -EFSCORRUPTED;
2002 			goto error0;
2003 		}
2004 		/*
2005 		 * Delete the old by-size entry on the right.
2006 		 */
2007 		if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i)))
2008 			goto error0;
2009 		if (XFS_IS_CORRUPT(mp, i != 1)) {
2010 			error = -EFSCORRUPTED;
2011 			goto error0;
2012 		}
2013 		if ((error = xfs_btree_delete(cnt_cur, &i)))
2014 			goto error0;
2015 		if (XFS_IS_CORRUPT(mp, i != 1)) {
2016 			error = -EFSCORRUPTED;
2017 			goto error0;
2018 		}
2019 		/*
2020 		 * Delete the old by-block entry for the right block.
2021 		 */
2022 		if ((error = xfs_btree_delete(bno_cur, &i)))
2023 			goto error0;
2024 		if (XFS_IS_CORRUPT(mp, i != 1)) {
2025 			error = -EFSCORRUPTED;
2026 			goto error0;
2027 		}
2028 		/*
2029 		 * Move the by-block cursor back to the left neighbor.
2030 		 */
2031 		if ((error = xfs_btree_decrement(bno_cur, 0, &i)))
2032 			goto error0;
2033 		if (XFS_IS_CORRUPT(mp, i != 1)) {
2034 			error = -EFSCORRUPTED;
2035 			goto error0;
2036 		}
2037 #ifdef DEBUG
2038 		/*
2039 		 * Check that this is the right record: delete didn't
2040 		 * mangle the cursor.
2041 		 */
2042 		{
2043 			xfs_agblock_t	xxbno;
2044 			xfs_extlen_t	xxlen;
2045 
2046 			if ((error = xfs_alloc_get_rec(bno_cur, &xxbno, &xxlen,
2047 					&i)))
2048 				goto error0;
2049 			if (XFS_IS_CORRUPT(mp,
2050 					   i != 1 ||
2051 					   xxbno != ltbno ||
2052 					   xxlen != ltlen)) {
2053 				error = -EFSCORRUPTED;
2054 				goto error0;
2055 			}
2056 		}
2057 #endif
2058 		/*
2059 		 * Update remaining by-block entry to the new, joined block.
2060 		 */
2061 		nbno = ltbno;
2062 		nlen = len + ltlen + gtlen;
2063 		if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
2064 			goto error0;
2065 	}
2066 	/*
2067 	 * Have only a left contiguous neighbor.
2068 	 * Merge it together with the new freespace.
2069 	 */
2070 	else if (haveleft) {
2071 		/*
2072 		 * Delete the old by-size entry on the left.
2073 		 */
2074 		if ((error = xfs_alloc_lookup_eq(cnt_cur, ltbno, ltlen, &i)))
2075 			goto error0;
2076 		if (XFS_IS_CORRUPT(mp, i != 1)) {
2077 			error = -EFSCORRUPTED;
2078 			goto error0;
2079 		}
2080 		if ((error = xfs_btree_delete(cnt_cur, &i)))
2081 			goto error0;
2082 		if (XFS_IS_CORRUPT(mp, i != 1)) {
2083 			error = -EFSCORRUPTED;
2084 			goto error0;
2085 		}
2086 		/*
2087 		 * Back up the by-block cursor to the left neighbor, and
2088 		 * update its length.
2089 		 */
2090 		if ((error = xfs_btree_decrement(bno_cur, 0, &i)))
2091 			goto error0;
2092 		if (XFS_IS_CORRUPT(mp, i != 1)) {
2093 			error = -EFSCORRUPTED;
2094 			goto error0;
2095 		}
2096 		nbno = ltbno;
2097 		nlen = len + ltlen;
2098 		if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
2099 			goto error0;
2100 	}
2101 	/*
2102 	 * Have only a right contiguous neighbor.
2103 	 * Merge it together with the new freespace.
2104 	 */
2105 	else if (haveright) {
2106 		/*
2107 		 * Delete the old by-size entry on the right.
2108 		 */
2109 		if ((error = xfs_alloc_lookup_eq(cnt_cur, gtbno, gtlen, &i)))
2110 			goto error0;
2111 		if (XFS_IS_CORRUPT(mp, i != 1)) {
2112 			error = -EFSCORRUPTED;
2113 			goto error0;
2114 		}
2115 		if ((error = xfs_btree_delete(cnt_cur, &i)))
2116 			goto error0;
2117 		if (XFS_IS_CORRUPT(mp, i != 1)) {
2118 			error = -EFSCORRUPTED;
2119 			goto error0;
2120 		}
2121 		/*
2122 		 * Update the starting block and length of the right
2123 		 * neighbor in the by-block tree.
2124 		 */
2125 		nbno = bno;
2126 		nlen = len + gtlen;
2127 		if ((error = xfs_alloc_update(bno_cur, nbno, nlen)))
2128 			goto error0;
2129 	}
2130 	/*
2131 	 * No contiguous neighbors.
2132 	 * Insert the new freespace into the by-block tree.
2133 	 */
2134 	else {
2135 		nbno = bno;
2136 		nlen = len;
2137 		if ((error = xfs_btree_insert(bno_cur, &i)))
2138 			goto error0;
2139 		if (XFS_IS_CORRUPT(mp, i != 1)) {
2140 			error = -EFSCORRUPTED;
2141 			goto error0;
2142 		}
2143 	}
2144 	xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
2145 	bno_cur = NULL;
2146 	/*
2147 	 * In all cases we need to insert the new freespace in the by-size tree.
2148 	 */
2149 	if ((error = xfs_alloc_lookup_eq(cnt_cur, nbno, nlen, &i)))
2150 		goto error0;
2151 	if (XFS_IS_CORRUPT(mp, i != 0)) {
2152 		error = -EFSCORRUPTED;
2153 		goto error0;
2154 	}
2155 	if ((error = xfs_btree_insert(cnt_cur, &i)))
2156 		goto error0;
2157 	if (XFS_IS_CORRUPT(mp, i != 1)) {
2158 		error = -EFSCORRUPTED;
2159 		goto error0;
2160 	}
2161 	xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
2162 	cnt_cur = NULL;
2163 
2164 	/*
2165 	 * Update the freespace totals in the ag and superblock.
2166 	 */
2167 	error = xfs_alloc_update_counters(tp, agbp, len);
2168 	xfs_ag_resv_free_extent(agbp->b_pag, type, tp, len);
2169 	if (error)
2170 		goto error0;
2171 
2172 	XFS_STATS_INC(mp, xs_freex);
2173 	XFS_STATS_ADD(mp, xs_freeb, len);
2174 
2175 	trace_xfs_free_extent(mp, agno, bno, len, type, haveleft, haveright);
2176 
2177 	return 0;
2178 
2179  error0:
2180 	trace_xfs_free_extent(mp, agno, bno, len, type, -1, -1);
2181 	if (bno_cur)
2182 		xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
2183 	if (cnt_cur)
2184 		xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
2185 	return error;
2186 }
2187 
2188 /*
2189  * Visible (exported) allocation/free functions.
2190  * Some of these are used just by xfs_alloc_btree.c and this file.
2191  */
2192 
2193 /*
2194  * Compute and fill in value of m_ag_maxlevels.
2195  */
2196 void
xfs_alloc_compute_maxlevels(xfs_mount_t * mp)2197 xfs_alloc_compute_maxlevels(
2198 	xfs_mount_t	*mp)	/* file system mount structure */
2199 {
2200 	mp->m_ag_maxlevels = xfs_btree_compute_maxlevels(mp->m_alloc_mnr,
2201 			(mp->m_sb.sb_agblocks + 1) / 2);
2202 }
2203 
2204 /*
2205  * Find the length of the longest extent in an AG.  The 'need' parameter
2206  * specifies how much space we're going to need for the AGFL and the
2207  * 'reserved' parameter tells us how many blocks in this AG are reserved for
2208  * other callers.
2209  */
2210 xfs_extlen_t
xfs_alloc_longest_free_extent(struct xfs_perag * pag,xfs_extlen_t need,xfs_extlen_t reserved)2211 xfs_alloc_longest_free_extent(
2212 	struct xfs_perag	*pag,
2213 	xfs_extlen_t		need,
2214 	xfs_extlen_t		reserved)
2215 {
2216 	xfs_extlen_t		delta = 0;
2217 
2218 	/*
2219 	 * If the AGFL needs a recharge, we'll have to subtract that from the
2220 	 * longest extent.
2221 	 */
2222 	if (need > pag->pagf_flcount)
2223 		delta = need - pag->pagf_flcount;
2224 
2225 	/*
2226 	 * If we cannot maintain others' reservations with space from the
2227 	 * not-longest freesp extents, we'll have to subtract /that/ from
2228 	 * the longest extent too.
2229 	 */
2230 	if (pag->pagf_freeblks - pag->pagf_longest < reserved)
2231 		delta += reserved - (pag->pagf_freeblks - pag->pagf_longest);
2232 
2233 	/*
2234 	 * If the longest extent is long enough to satisfy all the
2235 	 * reservations and AGFL rules in place, we can return this extent.
2236 	 */
2237 	if (pag->pagf_longest > delta)
2238 		return min_t(xfs_extlen_t, pag->pag_mount->m_ag_max_usable,
2239 				pag->pagf_longest - delta);
2240 
2241 	/* Otherwise, let the caller try for 1 block if there's space. */
2242 	return pag->pagf_flcount > 0 || pag->pagf_longest > 0;
2243 }
2244 
2245 /*
2246  * Compute the minimum length of the AGFL in the given AG.  If @pag is NULL,
2247  * return the largest possible minimum length.
2248  */
2249 unsigned int
xfs_alloc_min_freelist(struct xfs_mount * mp,struct xfs_perag * pag)2250 xfs_alloc_min_freelist(
2251 	struct xfs_mount	*mp,
2252 	struct xfs_perag	*pag)
2253 {
2254 	/* AG btrees have at least 1 level. */
2255 	static const uint8_t	fake_levels[XFS_BTNUM_AGF] = {1, 1, 1};
2256 	const uint8_t		*levels = pag ? pag->pagf_levels : fake_levels;
2257 	unsigned int		min_free;
2258 
2259 	ASSERT(mp->m_ag_maxlevels > 0);
2260 
2261 	/* space needed by-bno freespace btree */
2262 	min_free = min_t(unsigned int, levels[XFS_BTNUM_BNOi] + 1,
2263 				       mp->m_ag_maxlevels);
2264 	/* space needed by-size freespace btree */
2265 	min_free += min_t(unsigned int, levels[XFS_BTNUM_CNTi] + 1,
2266 				       mp->m_ag_maxlevels);
2267 	/* space needed reverse mapping used space btree */
2268 	if (xfs_sb_version_hasrmapbt(&mp->m_sb))
2269 		min_free += min_t(unsigned int, levels[XFS_BTNUM_RMAPi] + 1,
2270 						mp->m_rmap_maxlevels);
2271 
2272 	return min_free;
2273 }
2274 
2275 /*
2276  * Check if the operation we are fixing up the freelist for should go ahead or
2277  * not. If we are freeing blocks, we always allow it, otherwise the allocation
2278  * is dependent on whether the size and shape of free space available will
2279  * permit the requested allocation to take place.
2280  */
2281 static bool
xfs_alloc_space_available(struct xfs_alloc_arg * args,xfs_extlen_t min_free,int flags)2282 xfs_alloc_space_available(
2283 	struct xfs_alloc_arg	*args,
2284 	xfs_extlen_t		min_free,
2285 	int			flags)
2286 {
2287 	struct xfs_perag	*pag = args->pag;
2288 	xfs_extlen_t		alloc_len, longest;
2289 	xfs_extlen_t		reservation; /* blocks that are still reserved */
2290 	int			available;
2291 	xfs_extlen_t		agflcount;
2292 
2293 	if (flags & XFS_ALLOC_FLAG_FREEING)
2294 		return true;
2295 
2296 	reservation = xfs_ag_resv_needed(pag, args->resv);
2297 
2298 	/* do we have enough contiguous free space for the allocation? */
2299 	alloc_len = args->minlen + (args->alignment - 1) + args->minalignslop;
2300 	longest = xfs_alloc_longest_free_extent(pag, min_free, reservation);
2301 	if (longest < alloc_len)
2302 		return false;
2303 
2304 	/*
2305 	 * Do we have enough free space remaining for the allocation? Don't
2306 	 * account extra agfl blocks because we are about to defer free them,
2307 	 * making them unavailable until the current transaction commits.
2308 	 */
2309 	agflcount = min_t(xfs_extlen_t, pag->pagf_flcount, min_free);
2310 	available = (int)(pag->pagf_freeblks + agflcount -
2311 			  reservation - min_free - args->minleft);
2312 	if (available < (int)max(args->total, alloc_len))
2313 		return false;
2314 
2315 	/*
2316 	 * Clamp maxlen to the amount of free space available for the actual
2317 	 * extent allocation.
2318 	 */
2319 	if (available < (int)args->maxlen && !(flags & XFS_ALLOC_FLAG_CHECK)) {
2320 		args->maxlen = available;
2321 		ASSERT(args->maxlen > 0);
2322 		ASSERT(args->maxlen >= args->minlen);
2323 	}
2324 
2325 	return true;
2326 }
2327 
2328 int
xfs_free_agfl_block(struct xfs_trans * tp,xfs_agnumber_t agno,xfs_agblock_t agbno,struct xfs_buf * agbp,struct xfs_owner_info * oinfo)2329 xfs_free_agfl_block(
2330 	struct xfs_trans	*tp,
2331 	xfs_agnumber_t		agno,
2332 	xfs_agblock_t		agbno,
2333 	struct xfs_buf		*agbp,
2334 	struct xfs_owner_info	*oinfo)
2335 {
2336 	int			error;
2337 	struct xfs_buf		*bp;
2338 
2339 	error = xfs_free_ag_extent(tp, agbp, agno, agbno, 1, oinfo,
2340 				   XFS_AG_RESV_AGFL);
2341 	if (error)
2342 		return error;
2343 
2344 	error = xfs_trans_get_buf(tp, tp->t_mountp->m_ddev_targp,
2345 			XFS_AGB_TO_DADDR(tp->t_mountp, agno, agbno),
2346 			tp->t_mountp->m_bsize, 0, &bp);
2347 	if (error)
2348 		return error;
2349 	xfs_trans_binval(tp, bp);
2350 
2351 	return 0;
2352 }
2353 
2354 /*
2355  * Check the agfl fields of the agf for inconsistency or corruption. The purpose
2356  * is to detect an agfl header padding mismatch between current and early v5
2357  * kernels. This problem manifests as a 1-slot size difference between the
2358  * on-disk flcount and the active [first, last] range of a wrapped agfl. This
2359  * may also catch variants of agfl count corruption unrelated to padding. Either
2360  * way, we'll reset the agfl and warn the user.
2361  *
2362  * Return true if a reset is required before the agfl can be used, false
2363  * otherwise.
2364  */
2365 static bool
xfs_agfl_needs_reset(struct xfs_mount * mp,struct xfs_agf * agf)2366 xfs_agfl_needs_reset(
2367 	struct xfs_mount	*mp,
2368 	struct xfs_agf		*agf)
2369 {
2370 	uint32_t		f = be32_to_cpu(agf->agf_flfirst);
2371 	uint32_t		l = be32_to_cpu(agf->agf_fllast);
2372 	uint32_t		c = be32_to_cpu(agf->agf_flcount);
2373 	int			agfl_size = xfs_agfl_size(mp);
2374 	int			active;
2375 
2376 	/* no agfl header on v4 supers */
2377 	if (!xfs_sb_version_hascrc(&mp->m_sb))
2378 		return false;
2379 
2380 	/*
2381 	 * The agf read verifier catches severe corruption of these fields.
2382 	 * Repeat some sanity checks to cover a packed -> unpacked mismatch if
2383 	 * the verifier allows it.
2384 	 */
2385 	if (f >= agfl_size || l >= agfl_size)
2386 		return true;
2387 	if (c > agfl_size)
2388 		return true;
2389 
2390 	/*
2391 	 * Check consistency between the on-disk count and the active range. An
2392 	 * agfl padding mismatch manifests as an inconsistent flcount.
2393 	 */
2394 	if (c && l >= f)
2395 		active = l - f + 1;
2396 	else if (c)
2397 		active = agfl_size - f + l + 1;
2398 	else
2399 		active = 0;
2400 
2401 	return active != c;
2402 }
2403 
2404 /*
2405  * Reset the agfl to an empty state. Ignore/drop any existing blocks since the
2406  * agfl content cannot be trusted. Warn the user that a repair is required to
2407  * recover leaked blocks.
2408  *
2409  * The purpose of this mechanism is to handle filesystems affected by the agfl
2410  * header padding mismatch problem. A reset keeps the filesystem online with a
2411  * relatively minor free space accounting inconsistency rather than suffer the
2412  * inevitable crash from use of an invalid agfl block.
2413  */
2414 static void
xfs_agfl_reset(struct xfs_trans * tp,struct xfs_buf * agbp,struct xfs_perag * pag)2415 xfs_agfl_reset(
2416 	struct xfs_trans	*tp,
2417 	struct xfs_buf		*agbp,
2418 	struct xfs_perag	*pag)
2419 {
2420 	struct xfs_mount	*mp = tp->t_mountp;
2421 	struct xfs_agf		*agf = agbp->b_addr;
2422 
2423 	ASSERT(pag->pagf_agflreset);
2424 	trace_xfs_agfl_reset(mp, agf, 0, _RET_IP_);
2425 
2426 	xfs_warn(mp,
2427 	       "WARNING: Reset corrupted AGFL on AG %u. %d blocks leaked. "
2428 	       "Please unmount and run xfs_repair.",
2429 	         pag->pag_agno, pag->pagf_flcount);
2430 
2431 	agf->agf_flfirst = 0;
2432 	agf->agf_fllast = cpu_to_be32(xfs_agfl_size(mp) - 1);
2433 	agf->agf_flcount = 0;
2434 	xfs_alloc_log_agf(tp, agbp, XFS_AGF_FLFIRST | XFS_AGF_FLLAST |
2435 				    XFS_AGF_FLCOUNT);
2436 
2437 	pag->pagf_flcount = 0;
2438 	pag->pagf_agflreset = false;
2439 }
2440 
2441 /*
2442  * Defer an AGFL block free. This is effectively equivalent to
2443  * xfs_bmap_add_free() with some special handling particular to AGFL blocks.
2444  *
2445  * Deferring AGFL frees helps prevent log reservation overruns due to too many
2446  * allocation operations in a transaction. AGFL frees are prone to this problem
2447  * because for one they are always freed one at a time. Further, an immediate
2448  * AGFL block free can cause a btree join and require another block free before
2449  * the real allocation can proceed. Deferring the free disconnects freeing up
2450  * the AGFL slot from freeing the block.
2451  */
2452 STATIC void
xfs_defer_agfl_block(struct xfs_trans * tp,xfs_agnumber_t agno,xfs_fsblock_t agbno,struct xfs_owner_info * oinfo)2453 xfs_defer_agfl_block(
2454 	struct xfs_trans		*tp,
2455 	xfs_agnumber_t			agno,
2456 	xfs_fsblock_t			agbno,
2457 	struct xfs_owner_info		*oinfo)
2458 {
2459 	struct xfs_mount		*mp = tp->t_mountp;
2460 	struct xfs_extent_free_item	*new;		/* new element */
2461 
2462 	ASSERT(xfs_bmap_free_item_zone != NULL);
2463 	ASSERT(oinfo != NULL);
2464 
2465 	new = kmem_cache_alloc(xfs_bmap_free_item_zone,
2466 			       GFP_KERNEL | __GFP_NOFAIL);
2467 	new->xefi_startblock = XFS_AGB_TO_FSB(mp, agno, agbno);
2468 	new->xefi_blockcount = 1;
2469 	new->xefi_oinfo = *oinfo;
2470 	new->xefi_skip_discard = false;
2471 
2472 	trace_xfs_agfl_free_defer(mp, agno, 0, agbno, 1);
2473 
2474 	xfs_defer_add(tp, XFS_DEFER_OPS_TYPE_AGFL_FREE, &new->xefi_list);
2475 }
2476 
2477 /*
2478  * Decide whether to use this allocation group for this allocation.
2479  * If so, fix up the btree freelist's size.
2480  */
2481 int			/* error */
xfs_alloc_fix_freelist(struct xfs_alloc_arg * args,int flags)2482 xfs_alloc_fix_freelist(
2483 	struct xfs_alloc_arg	*args,	/* allocation argument structure */
2484 	int			flags)	/* XFS_ALLOC_FLAG_... */
2485 {
2486 	struct xfs_mount	*mp = args->mp;
2487 	struct xfs_perag	*pag = args->pag;
2488 	struct xfs_trans	*tp = args->tp;
2489 	struct xfs_buf		*agbp = NULL;
2490 	struct xfs_buf		*agflbp = NULL;
2491 	struct xfs_alloc_arg	targs;	/* local allocation arguments */
2492 	xfs_agblock_t		bno;	/* freelist block */
2493 	xfs_extlen_t		need;	/* total blocks needed in freelist */
2494 	int			error = 0;
2495 
2496 	/* deferred ops (AGFL block frees) require permanent transactions */
2497 	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
2498 
2499 	if (!pag->pagf_init) {
2500 		error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp);
2501 		if (error) {
2502 			/* Couldn't lock the AGF so skip this AG. */
2503 			if (error == -EAGAIN)
2504 				error = 0;
2505 			goto out_no_agbp;
2506 		}
2507 	}
2508 
2509 	/*
2510 	 * If this is a metadata preferred pag and we are user data then try
2511 	 * somewhere else if we are not being asked to try harder at this
2512 	 * point
2513 	 */
2514 	if (pag->pagf_metadata && (args->datatype & XFS_ALLOC_USERDATA) &&
2515 	    (flags & XFS_ALLOC_FLAG_TRYLOCK)) {
2516 		ASSERT(!(flags & XFS_ALLOC_FLAG_FREEING));
2517 		goto out_agbp_relse;
2518 	}
2519 
2520 	need = xfs_alloc_min_freelist(mp, pag);
2521 	if (!xfs_alloc_space_available(args, need, flags |
2522 			XFS_ALLOC_FLAG_CHECK))
2523 		goto out_agbp_relse;
2524 
2525 	/*
2526 	 * Get the a.g. freespace buffer.
2527 	 * Can fail if we're not blocking on locks, and it's held.
2528 	 */
2529 	if (!agbp) {
2530 		error = xfs_alloc_read_agf(mp, tp, args->agno, flags, &agbp);
2531 		if (error) {
2532 			/* Couldn't lock the AGF so skip this AG. */
2533 			if (error == -EAGAIN)
2534 				error = 0;
2535 			goto out_no_agbp;
2536 		}
2537 	}
2538 
2539 	/* reset a padding mismatched agfl before final free space check */
2540 	if (pag->pagf_agflreset)
2541 		xfs_agfl_reset(tp, agbp, pag);
2542 
2543 	/* If there isn't enough total space or single-extent, reject it. */
2544 	need = xfs_alloc_min_freelist(mp, pag);
2545 	if (!xfs_alloc_space_available(args, need, flags))
2546 		goto out_agbp_relse;
2547 
2548 	/*
2549 	 * Make the freelist shorter if it's too long.
2550 	 *
2551 	 * Note that from this point onwards, we will always release the agf and
2552 	 * agfl buffers on error. This handles the case where we error out and
2553 	 * the buffers are clean or may not have been joined to the transaction
2554 	 * and hence need to be released manually. If they have been joined to
2555 	 * the transaction, then xfs_trans_brelse() will handle them
2556 	 * appropriately based on the recursion count and dirty state of the
2557 	 * buffer.
2558 	 *
2559 	 * XXX (dgc): When we have lots of free space, does this buy us
2560 	 * anything other than extra overhead when we need to put more blocks
2561 	 * back on the free list? Maybe we should only do this when space is
2562 	 * getting low or the AGFL is more than half full?
2563 	 *
2564 	 * The NOSHRINK flag prevents the AGFL from being shrunk if it's too
2565 	 * big; the NORMAP flag prevents AGFL expand/shrink operations from
2566 	 * updating the rmapbt.  Both flags are used in xfs_repair while we're
2567 	 * rebuilding the rmapbt, and neither are used by the kernel.  They're
2568 	 * both required to ensure that rmaps are correctly recorded for the
2569 	 * regenerated AGFL, bnobt, and cntbt.  See repair/phase5.c and
2570 	 * repair/rmap.c in xfsprogs for details.
2571 	 */
2572 	memset(&targs, 0, sizeof(targs));
2573 	/* struct copy below */
2574 	if (flags & XFS_ALLOC_FLAG_NORMAP)
2575 		targs.oinfo = XFS_RMAP_OINFO_SKIP_UPDATE;
2576 	else
2577 		targs.oinfo = XFS_RMAP_OINFO_AG;
2578 	while (!(flags & XFS_ALLOC_FLAG_NOSHRINK) && pag->pagf_flcount > need) {
2579 		error = xfs_alloc_get_freelist(tp, agbp, &bno, 0);
2580 		if (error)
2581 			goto out_agbp_relse;
2582 
2583 		/* defer agfl frees */
2584 		xfs_defer_agfl_block(tp, args->agno, bno, &targs.oinfo);
2585 	}
2586 
2587 	targs.tp = tp;
2588 	targs.mp = mp;
2589 	targs.agbp = agbp;
2590 	targs.agno = args->agno;
2591 	targs.alignment = targs.minlen = targs.prod = 1;
2592 	targs.type = XFS_ALLOCTYPE_THIS_AG;
2593 	targs.pag = pag;
2594 	error = xfs_alloc_read_agfl(mp, tp, targs.agno, &agflbp);
2595 	if (error)
2596 		goto out_agbp_relse;
2597 
2598 	/* Make the freelist longer if it's too short. */
2599 	while (pag->pagf_flcount < need) {
2600 		targs.agbno = 0;
2601 		targs.maxlen = need - pag->pagf_flcount;
2602 		targs.resv = XFS_AG_RESV_AGFL;
2603 
2604 		/* Allocate as many blocks as possible at once. */
2605 		error = xfs_alloc_ag_vextent(&targs);
2606 		if (error)
2607 			goto out_agflbp_relse;
2608 
2609 		/*
2610 		 * Stop if we run out.  Won't happen if callers are obeying
2611 		 * the restrictions correctly.  Can happen for free calls
2612 		 * on a completely full ag.
2613 		 */
2614 		if (targs.agbno == NULLAGBLOCK) {
2615 			if (flags & XFS_ALLOC_FLAG_FREEING)
2616 				break;
2617 			goto out_agflbp_relse;
2618 		}
2619 		/*
2620 		 * Put each allocated block on the list.
2621 		 */
2622 		for (bno = targs.agbno; bno < targs.agbno + targs.len; bno++) {
2623 			error = xfs_alloc_put_freelist(tp, agbp,
2624 							agflbp, bno, 0);
2625 			if (error)
2626 				goto out_agflbp_relse;
2627 		}
2628 	}
2629 	xfs_trans_brelse(tp, agflbp);
2630 	args->agbp = agbp;
2631 	return 0;
2632 
2633 out_agflbp_relse:
2634 	xfs_trans_brelse(tp, agflbp);
2635 out_agbp_relse:
2636 	if (agbp)
2637 		xfs_trans_brelse(tp, agbp);
2638 out_no_agbp:
2639 	args->agbp = NULL;
2640 	return error;
2641 }
2642 
2643 /*
2644  * Get a block from the freelist.
2645  * Returns with the buffer for the block gotten.
2646  */
2647 int				/* error */
xfs_alloc_get_freelist(xfs_trans_t * tp,xfs_buf_t * agbp,xfs_agblock_t * bnop,int btreeblk)2648 xfs_alloc_get_freelist(
2649 	xfs_trans_t	*tp,	/* transaction pointer */
2650 	xfs_buf_t	*agbp,	/* buffer containing the agf structure */
2651 	xfs_agblock_t	*bnop,	/* block address retrieved from freelist */
2652 	int		btreeblk) /* destination is a AGF btree */
2653 {
2654 	struct xfs_agf	*agf = agbp->b_addr;
2655 	xfs_buf_t	*agflbp;/* buffer for a.g. freelist structure */
2656 	xfs_agblock_t	bno;	/* block number returned */
2657 	__be32		*agfl_bno;
2658 	int		error;
2659 	int		logflags;
2660 	xfs_mount_t	*mp = tp->t_mountp;
2661 	xfs_perag_t	*pag;	/* per allocation group data */
2662 
2663 	/*
2664 	 * Freelist is empty, give up.
2665 	 */
2666 	if (!agf->agf_flcount) {
2667 		*bnop = NULLAGBLOCK;
2668 		return 0;
2669 	}
2670 	/*
2671 	 * Read the array of free blocks.
2672 	 */
2673 	error = xfs_alloc_read_agfl(mp, tp, be32_to_cpu(agf->agf_seqno),
2674 				    &agflbp);
2675 	if (error)
2676 		return error;
2677 
2678 
2679 	/*
2680 	 * Get the block number and update the data structures.
2681 	 */
2682 	agfl_bno = xfs_buf_to_agfl_bno(agflbp);
2683 	bno = be32_to_cpu(agfl_bno[be32_to_cpu(agf->agf_flfirst)]);
2684 	be32_add_cpu(&agf->agf_flfirst, 1);
2685 	xfs_trans_brelse(tp, agflbp);
2686 	if (be32_to_cpu(agf->agf_flfirst) == xfs_agfl_size(mp))
2687 		agf->agf_flfirst = 0;
2688 
2689 	pag = agbp->b_pag;
2690 	ASSERT(!pag->pagf_agflreset);
2691 	be32_add_cpu(&agf->agf_flcount, -1);
2692 	xfs_trans_agflist_delta(tp, -1);
2693 	pag->pagf_flcount--;
2694 
2695 	logflags = XFS_AGF_FLFIRST | XFS_AGF_FLCOUNT;
2696 	if (btreeblk) {
2697 		be32_add_cpu(&agf->agf_btreeblks, 1);
2698 		pag->pagf_btreeblks++;
2699 		logflags |= XFS_AGF_BTREEBLKS;
2700 	}
2701 
2702 	xfs_alloc_log_agf(tp, agbp, logflags);
2703 	*bnop = bno;
2704 
2705 	return 0;
2706 }
2707 
2708 /*
2709  * Log the given fields from the agf structure.
2710  */
2711 void
xfs_alloc_log_agf(xfs_trans_t * tp,xfs_buf_t * bp,int fields)2712 xfs_alloc_log_agf(
2713 	xfs_trans_t	*tp,	/* transaction pointer */
2714 	xfs_buf_t	*bp,	/* buffer for a.g. freelist header */
2715 	int		fields)	/* mask of fields to be logged (XFS_AGF_...) */
2716 {
2717 	int	first;		/* first byte offset */
2718 	int	last;		/* last byte offset */
2719 	static const short	offsets[] = {
2720 		offsetof(xfs_agf_t, agf_magicnum),
2721 		offsetof(xfs_agf_t, agf_versionnum),
2722 		offsetof(xfs_agf_t, agf_seqno),
2723 		offsetof(xfs_agf_t, agf_length),
2724 		offsetof(xfs_agf_t, agf_roots[0]),
2725 		offsetof(xfs_agf_t, agf_levels[0]),
2726 		offsetof(xfs_agf_t, agf_flfirst),
2727 		offsetof(xfs_agf_t, agf_fllast),
2728 		offsetof(xfs_agf_t, agf_flcount),
2729 		offsetof(xfs_agf_t, agf_freeblks),
2730 		offsetof(xfs_agf_t, agf_longest),
2731 		offsetof(xfs_agf_t, agf_btreeblks),
2732 		offsetof(xfs_agf_t, agf_uuid),
2733 		offsetof(xfs_agf_t, agf_rmap_blocks),
2734 		offsetof(xfs_agf_t, agf_refcount_blocks),
2735 		offsetof(xfs_agf_t, agf_refcount_root),
2736 		offsetof(xfs_agf_t, agf_refcount_level),
2737 		/* needed so that we don't log the whole rest of the structure: */
2738 		offsetof(xfs_agf_t, agf_spare64),
2739 		sizeof(xfs_agf_t)
2740 	};
2741 
2742 	trace_xfs_agf(tp->t_mountp, bp->b_addr, fields, _RET_IP_);
2743 
2744 	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_AGF_BUF);
2745 
2746 	xfs_btree_offsets(fields, offsets, XFS_AGF_NUM_BITS, &first, &last);
2747 	xfs_trans_log_buf(tp, bp, (uint)first, (uint)last);
2748 }
2749 
2750 /*
2751  * Interface for inode allocation to force the pag data to be initialized.
2752  */
2753 int					/* error */
xfs_alloc_pagf_init(xfs_mount_t * mp,xfs_trans_t * tp,xfs_agnumber_t agno,int flags)2754 xfs_alloc_pagf_init(
2755 	xfs_mount_t		*mp,	/* file system mount structure */
2756 	xfs_trans_t		*tp,	/* transaction pointer */
2757 	xfs_agnumber_t		agno,	/* allocation group number */
2758 	int			flags)	/* XFS_ALLOC_FLAGS_... */
2759 {
2760 	xfs_buf_t		*bp;
2761 	int			error;
2762 
2763 	error = xfs_alloc_read_agf(mp, tp, agno, flags, &bp);
2764 	if (!error)
2765 		xfs_trans_brelse(tp, bp);
2766 	return error;
2767 }
2768 
2769 /*
2770  * Put the block on the freelist for the allocation group.
2771  */
2772 int					/* error */
xfs_alloc_put_freelist(xfs_trans_t * tp,xfs_buf_t * agbp,xfs_buf_t * agflbp,xfs_agblock_t bno,int btreeblk)2773 xfs_alloc_put_freelist(
2774 	xfs_trans_t		*tp,	/* transaction pointer */
2775 	xfs_buf_t		*agbp,	/* buffer for a.g. freelist header */
2776 	xfs_buf_t		*agflbp,/* buffer for a.g. free block array */
2777 	xfs_agblock_t		bno,	/* block being freed */
2778 	int			btreeblk) /* block came from a AGF btree */
2779 {
2780 	struct xfs_mount	*mp = tp->t_mountp;
2781 	struct xfs_agf		*agf = agbp->b_addr;
2782 	__be32			*blockp;/* pointer to array entry */
2783 	int			error;
2784 	int			logflags;
2785 	xfs_perag_t		*pag;	/* per allocation group data */
2786 	__be32			*agfl_bno;
2787 	int			startoff;
2788 
2789 	if (!agflbp && (error = xfs_alloc_read_agfl(mp, tp,
2790 			be32_to_cpu(agf->agf_seqno), &agflbp)))
2791 		return error;
2792 	be32_add_cpu(&agf->agf_fllast, 1);
2793 	if (be32_to_cpu(agf->agf_fllast) == xfs_agfl_size(mp))
2794 		agf->agf_fllast = 0;
2795 
2796 	pag = agbp->b_pag;
2797 	ASSERT(!pag->pagf_agflreset);
2798 	be32_add_cpu(&agf->agf_flcount, 1);
2799 	xfs_trans_agflist_delta(tp, 1);
2800 	pag->pagf_flcount++;
2801 
2802 	logflags = XFS_AGF_FLLAST | XFS_AGF_FLCOUNT;
2803 	if (btreeblk) {
2804 		be32_add_cpu(&agf->agf_btreeblks, -1);
2805 		pag->pagf_btreeblks--;
2806 		logflags |= XFS_AGF_BTREEBLKS;
2807 	}
2808 
2809 	xfs_alloc_log_agf(tp, agbp, logflags);
2810 
2811 	ASSERT(be32_to_cpu(agf->agf_flcount) <= xfs_agfl_size(mp));
2812 
2813 	agfl_bno = xfs_buf_to_agfl_bno(agflbp);
2814 	blockp = &agfl_bno[be32_to_cpu(agf->agf_fllast)];
2815 	*blockp = cpu_to_be32(bno);
2816 	startoff = (char *)blockp - (char *)agflbp->b_addr;
2817 
2818 	xfs_alloc_log_agf(tp, agbp, logflags);
2819 
2820 	xfs_trans_buf_set_type(tp, agflbp, XFS_BLFT_AGFL_BUF);
2821 	xfs_trans_log_buf(tp, agflbp, startoff,
2822 			  startoff + sizeof(xfs_agblock_t) - 1);
2823 	return 0;
2824 }
2825 
2826 static xfs_failaddr_t
xfs_agf_verify(struct xfs_buf * bp)2827 xfs_agf_verify(
2828 	struct xfs_buf		*bp)
2829 {
2830 	struct xfs_mount	*mp = bp->b_mount;
2831 	struct xfs_agf		*agf = bp->b_addr;
2832 
2833 	if (xfs_sb_version_hascrc(&mp->m_sb)) {
2834 		if (!uuid_equal(&agf->agf_uuid, &mp->m_sb.sb_meta_uuid))
2835 			return __this_address;
2836 		if (!xfs_log_check_lsn(mp, be64_to_cpu(agf->agf_lsn)))
2837 			return __this_address;
2838 	}
2839 
2840 	if (!xfs_verify_magic(bp, agf->agf_magicnum))
2841 		return __this_address;
2842 
2843 	if (!(XFS_AGF_GOOD_VERSION(be32_to_cpu(agf->agf_versionnum)) &&
2844 	      be32_to_cpu(agf->agf_freeblks) <= be32_to_cpu(agf->agf_length) &&
2845 	      be32_to_cpu(agf->agf_flfirst) < xfs_agfl_size(mp) &&
2846 	      be32_to_cpu(agf->agf_fllast) < xfs_agfl_size(mp) &&
2847 	      be32_to_cpu(agf->agf_flcount) <= xfs_agfl_size(mp)))
2848 		return __this_address;
2849 
2850 	if (be32_to_cpu(agf->agf_length) > mp->m_sb.sb_dblocks)
2851 		return __this_address;
2852 
2853 	if (be32_to_cpu(agf->agf_freeblks) < be32_to_cpu(agf->agf_longest) ||
2854 	    be32_to_cpu(agf->agf_freeblks) > be32_to_cpu(agf->agf_length))
2855 		return __this_address;
2856 
2857 	if (be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]) < 1 ||
2858 	    be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]) < 1 ||
2859 	    be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]) > XFS_BTREE_MAXLEVELS ||
2860 	    be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]) > XFS_BTREE_MAXLEVELS)
2861 		return __this_address;
2862 
2863 	if (xfs_sb_version_hasrmapbt(&mp->m_sb) &&
2864 	    (be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) < 1 ||
2865 	     be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]) > XFS_BTREE_MAXLEVELS))
2866 		return __this_address;
2867 
2868 	if (xfs_sb_version_hasrmapbt(&mp->m_sb) &&
2869 	    be32_to_cpu(agf->agf_rmap_blocks) > be32_to_cpu(agf->agf_length))
2870 		return __this_address;
2871 
2872 	/*
2873 	 * during growfs operations, the perag is not fully initialised,
2874 	 * so we can't use it for any useful checking. growfs ensures we can't
2875 	 * use it by using uncached buffers that don't have the perag attached
2876 	 * so we can detect and avoid this problem.
2877 	 */
2878 	if (bp->b_pag && be32_to_cpu(agf->agf_seqno) != bp->b_pag->pag_agno)
2879 		return __this_address;
2880 
2881 	if (xfs_sb_version_haslazysbcount(&mp->m_sb) &&
2882 	    be32_to_cpu(agf->agf_btreeblks) > be32_to_cpu(agf->agf_length))
2883 		return __this_address;
2884 
2885 	if (xfs_sb_version_hasreflink(&mp->m_sb) &&
2886 	    be32_to_cpu(agf->agf_refcount_blocks) >
2887 	    be32_to_cpu(agf->agf_length))
2888 		return __this_address;
2889 
2890 	if (xfs_sb_version_hasreflink(&mp->m_sb) &&
2891 	    (be32_to_cpu(agf->agf_refcount_level) < 1 ||
2892 	     be32_to_cpu(agf->agf_refcount_level) > XFS_BTREE_MAXLEVELS))
2893 		return __this_address;
2894 
2895 	return NULL;
2896 
2897 }
2898 
2899 static void
xfs_agf_read_verify(struct xfs_buf * bp)2900 xfs_agf_read_verify(
2901 	struct xfs_buf	*bp)
2902 {
2903 	struct xfs_mount *mp = bp->b_mount;
2904 	xfs_failaddr_t	fa;
2905 
2906 	if (xfs_sb_version_hascrc(&mp->m_sb) &&
2907 	    !xfs_buf_verify_cksum(bp, XFS_AGF_CRC_OFF))
2908 		xfs_verifier_error(bp, -EFSBADCRC, __this_address);
2909 	else {
2910 		fa = xfs_agf_verify(bp);
2911 		if (XFS_TEST_ERROR(fa, mp, XFS_ERRTAG_ALLOC_READ_AGF))
2912 			xfs_verifier_error(bp, -EFSCORRUPTED, fa);
2913 	}
2914 }
2915 
2916 static void
xfs_agf_write_verify(struct xfs_buf * bp)2917 xfs_agf_write_verify(
2918 	struct xfs_buf	*bp)
2919 {
2920 	struct xfs_mount	*mp = bp->b_mount;
2921 	struct xfs_buf_log_item	*bip = bp->b_log_item;
2922 	struct xfs_agf		*agf = bp->b_addr;
2923 	xfs_failaddr_t		fa;
2924 
2925 	fa = xfs_agf_verify(bp);
2926 	if (fa) {
2927 		xfs_verifier_error(bp, -EFSCORRUPTED, fa);
2928 		return;
2929 	}
2930 
2931 	if (!xfs_sb_version_hascrc(&mp->m_sb))
2932 		return;
2933 
2934 	if (bip)
2935 		agf->agf_lsn = cpu_to_be64(bip->bli_item.li_lsn);
2936 
2937 	xfs_buf_update_cksum(bp, XFS_AGF_CRC_OFF);
2938 }
2939 
2940 const struct xfs_buf_ops xfs_agf_buf_ops = {
2941 	.name = "xfs_agf",
2942 	.magic = { cpu_to_be32(XFS_AGF_MAGIC), cpu_to_be32(XFS_AGF_MAGIC) },
2943 	.verify_read = xfs_agf_read_verify,
2944 	.verify_write = xfs_agf_write_verify,
2945 	.verify_struct = xfs_agf_verify,
2946 };
2947 
2948 /*
2949  * Read in the allocation group header (free/alloc section).
2950  */
2951 int					/* error */
xfs_read_agf(struct xfs_mount * mp,struct xfs_trans * tp,xfs_agnumber_t agno,int flags,struct xfs_buf ** bpp)2952 xfs_read_agf(
2953 	struct xfs_mount	*mp,	/* mount point structure */
2954 	struct xfs_trans	*tp,	/* transaction pointer */
2955 	xfs_agnumber_t		agno,	/* allocation group number */
2956 	int			flags,	/* XFS_BUF_ */
2957 	struct xfs_buf		**bpp)	/* buffer for the ag freelist header */
2958 {
2959 	int		error;
2960 
2961 	trace_xfs_read_agf(mp, agno);
2962 
2963 	ASSERT(agno != NULLAGNUMBER);
2964 	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
2965 			XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
2966 			XFS_FSS_TO_BB(mp, 1), flags, bpp, &xfs_agf_buf_ops);
2967 	if (error)
2968 		return error;
2969 
2970 	ASSERT(!(*bpp)->b_error);
2971 	xfs_buf_set_ref(*bpp, XFS_AGF_REF);
2972 	return 0;
2973 }
2974 
2975 /*
2976  * Read in the allocation group header (free/alloc section).
2977  */
2978 int					/* error */
xfs_alloc_read_agf(struct xfs_mount * mp,struct xfs_trans * tp,xfs_agnumber_t agno,int flags,struct xfs_buf ** bpp)2979 xfs_alloc_read_agf(
2980 	struct xfs_mount	*mp,	/* mount point structure */
2981 	struct xfs_trans	*tp,	/* transaction pointer */
2982 	xfs_agnumber_t		agno,	/* allocation group number */
2983 	int			flags,	/* XFS_ALLOC_FLAG_... */
2984 	struct xfs_buf		**bpp)	/* buffer for the ag freelist header */
2985 {
2986 	struct xfs_agf		*agf;		/* ag freelist header */
2987 	struct xfs_perag	*pag;		/* per allocation group data */
2988 	int			error;
2989 
2990 	trace_xfs_alloc_read_agf(mp, agno);
2991 
2992 	/* We don't support trylock when freeing. */
2993 	ASSERT((flags & (XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK)) !=
2994 			(XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK));
2995 	ASSERT(agno != NULLAGNUMBER);
2996 	error = xfs_read_agf(mp, tp, agno,
2997 			(flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0,
2998 			bpp);
2999 	if (error)
3000 		return error;
3001 	ASSERT(!(*bpp)->b_error);
3002 
3003 	agf = (*bpp)->b_addr;
3004 	pag = (*bpp)->b_pag;
3005 	if (!pag->pagf_init) {
3006 		pag->pagf_freeblks = be32_to_cpu(agf->agf_freeblks);
3007 		pag->pagf_btreeblks = be32_to_cpu(agf->agf_btreeblks);
3008 		pag->pagf_flcount = be32_to_cpu(agf->agf_flcount);
3009 		pag->pagf_longest = be32_to_cpu(agf->agf_longest);
3010 		pag->pagf_levels[XFS_BTNUM_BNOi] =
3011 			be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]);
3012 		pag->pagf_levels[XFS_BTNUM_CNTi] =
3013 			be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]);
3014 		pag->pagf_levels[XFS_BTNUM_RMAPi] =
3015 			be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAPi]);
3016 		pag->pagf_refcount_level = be32_to_cpu(agf->agf_refcount_level);
3017 		pag->pagf_init = 1;
3018 		pag->pagf_agflreset = xfs_agfl_needs_reset(mp, agf);
3019 	}
3020 #ifdef DEBUG
3021 	else if (!XFS_FORCED_SHUTDOWN(mp)) {
3022 		ASSERT(pag->pagf_freeblks == be32_to_cpu(agf->agf_freeblks));
3023 		ASSERT(pag->pagf_btreeblks == be32_to_cpu(agf->agf_btreeblks));
3024 		ASSERT(pag->pagf_flcount == be32_to_cpu(agf->agf_flcount));
3025 		ASSERT(pag->pagf_longest == be32_to_cpu(agf->agf_longest));
3026 		ASSERT(pag->pagf_levels[XFS_BTNUM_BNOi] ==
3027 		       be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNOi]));
3028 		ASSERT(pag->pagf_levels[XFS_BTNUM_CNTi] ==
3029 		       be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNTi]));
3030 	}
3031 #endif
3032 	return 0;
3033 }
3034 
3035 /*
3036  * Allocate an extent (variable-size).
3037  * Depending on the allocation type, we either look in a single allocation
3038  * group or loop over the allocation groups to find the result.
3039  */
3040 int				/* error */
xfs_alloc_vextent(struct xfs_alloc_arg * args)3041 xfs_alloc_vextent(
3042 	struct xfs_alloc_arg	*args)	/* allocation argument structure */
3043 {
3044 	xfs_agblock_t		agsize;	/* allocation group size */
3045 	int			error;
3046 	int			flags;	/* XFS_ALLOC_FLAG_... locking flags */
3047 	struct xfs_mount	*mp;	/* mount structure pointer */
3048 	xfs_agnumber_t		sagno;	/* starting allocation group number */
3049 	xfs_alloctype_t		type;	/* input allocation type */
3050 	int			bump_rotor = 0;
3051 	xfs_agnumber_t		rotorstep = xfs_rotorstep; /* inode32 agf stepper */
3052 
3053 	mp = args->mp;
3054 	type = args->otype = args->type;
3055 	args->agbno = NULLAGBLOCK;
3056 	/*
3057 	 * Just fix this up, for the case where the last a.g. is shorter
3058 	 * (or there's only one a.g.) and the caller couldn't easily figure
3059 	 * that out (xfs_bmap_alloc).
3060 	 */
3061 	agsize = mp->m_sb.sb_agblocks;
3062 	if (args->maxlen > agsize)
3063 		args->maxlen = agsize;
3064 	if (args->alignment == 0)
3065 		args->alignment = 1;
3066 	ASSERT(XFS_FSB_TO_AGNO(mp, args->fsbno) < mp->m_sb.sb_agcount);
3067 	ASSERT(XFS_FSB_TO_AGBNO(mp, args->fsbno) < agsize);
3068 	ASSERT(args->minlen <= args->maxlen);
3069 	ASSERT(args->minlen <= agsize);
3070 	ASSERT(args->mod < args->prod);
3071 	if (XFS_FSB_TO_AGNO(mp, args->fsbno) >= mp->m_sb.sb_agcount ||
3072 	    XFS_FSB_TO_AGBNO(mp, args->fsbno) >= agsize ||
3073 	    args->minlen > args->maxlen || args->minlen > agsize ||
3074 	    args->mod >= args->prod) {
3075 		args->fsbno = NULLFSBLOCK;
3076 		trace_xfs_alloc_vextent_badargs(args);
3077 		return 0;
3078 	}
3079 
3080 	switch (type) {
3081 	case XFS_ALLOCTYPE_THIS_AG:
3082 	case XFS_ALLOCTYPE_NEAR_BNO:
3083 	case XFS_ALLOCTYPE_THIS_BNO:
3084 		/*
3085 		 * These three force us into a single a.g.
3086 		 */
3087 		args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
3088 		args->pag = xfs_perag_get(mp, args->agno);
3089 		error = xfs_alloc_fix_freelist(args, 0);
3090 		if (error) {
3091 			trace_xfs_alloc_vextent_nofix(args);
3092 			goto error0;
3093 		}
3094 		if (!args->agbp) {
3095 			trace_xfs_alloc_vextent_noagbp(args);
3096 			break;
3097 		}
3098 		args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);
3099 		if ((error = xfs_alloc_ag_vextent(args)))
3100 			goto error0;
3101 		break;
3102 	case XFS_ALLOCTYPE_START_BNO:
3103 		/*
3104 		 * Try near allocation first, then anywhere-in-ag after
3105 		 * the first a.g. fails.
3106 		 */
3107 		if ((args->datatype & XFS_ALLOC_INITIAL_USER_DATA) &&
3108 		    (mp->m_flags & XFS_MOUNT_32BITINODES)) {
3109 			args->fsbno = XFS_AGB_TO_FSB(mp,
3110 					((mp->m_agfrotor / rotorstep) %
3111 					mp->m_sb.sb_agcount), 0);
3112 			bump_rotor = 1;
3113 		}
3114 		args->agbno = XFS_FSB_TO_AGBNO(mp, args->fsbno);
3115 		args->type = XFS_ALLOCTYPE_NEAR_BNO;
3116 		/* FALLTHROUGH */
3117 	case XFS_ALLOCTYPE_FIRST_AG:
3118 		/*
3119 		 * Rotate through the allocation groups looking for a winner.
3120 		 */
3121 		if (type == XFS_ALLOCTYPE_FIRST_AG) {
3122 			/*
3123 			 * Start with allocation group given by bno.
3124 			 */
3125 			args->agno = XFS_FSB_TO_AGNO(mp, args->fsbno);
3126 			args->type = XFS_ALLOCTYPE_THIS_AG;
3127 			sagno = 0;
3128 			flags = 0;
3129 		} else {
3130 			/*
3131 			 * Start with the given allocation group.
3132 			 */
3133 			args->agno = sagno = XFS_FSB_TO_AGNO(mp, args->fsbno);
3134 			flags = XFS_ALLOC_FLAG_TRYLOCK;
3135 		}
3136 		/*
3137 		 * Loop over allocation groups twice; first time with
3138 		 * trylock set, second time without.
3139 		 */
3140 		for (;;) {
3141 			args->pag = xfs_perag_get(mp, args->agno);
3142 			error = xfs_alloc_fix_freelist(args, flags);
3143 			if (error) {
3144 				trace_xfs_alloc_vextent_nofix(args);
3145 				goto error0;
3146 			}
3147 			/*
3148 			 * If we get a buffer back then the allocation will fly.
3149 			 */
3150 			if (args->agbp) {
3151 				if ((error = xfs_alloc_ag_vextent(args)))
3152 					goto error0;
3153 				break;
3154 			}
3155 
3156 			trace_xfs_alloc_vextent_loopfailed(args);
3157 
3158 			/*
3159 			 * Didn't work, figure out the next iteration.
3160 			 */
3161 			if (args->agno == sagno &&
3162 			    type == XFS_ALLOCTYPE_START_BNO)
3163 				args->type = XFS_ALLOCTYPE_THIS_AG;
3164 			/*
3165 			* For the first allocation, we can try any AG to get
3166 			* space.  However, if we already have allocated a
3167 			* block, we don't want to try AGs whose number is below
3168 			* sagno. Otherwise, we may end up with out-of-order
3169 			* locking of AGF, which might cause deadlock.
3170 			*/
3171 			if (++(args->agno) == mp->m_sb.sb_agcount) {
3172 				if (args->tp->t_firstblock != NULLFSBLOCK)
3173 					args->agno = sagno;
3174 				else
3175 					args->agno = 0;
3176 			}
3177 			/*
3178 			 * Reached the starting a.g., must either be done
3179 			 * or switch to non-trylock mode.
3180 			 */
3181 			if (args->agno == sagno) {
3182 				if (flags == 0) {
3183 					args->agbno = NULLAGBLOCK;
3184 					trace_xfs_alloc_vextent_allfailed(args);
3185 					break;
3186 				}
3187 
3188 				flags = 0;
3189 				if (type == XFS_ALLOCTYPE_START_BNO) {
3190 					args->agbno = XFS_FSB_TO_AGBNO(mp,
3191 						args->fsbno);
3192 					args->type = XFS_ALLOCTYPE_NEAR_BNO;
3193 				}
3194 			}
3195 			xfs_perag_put(args->pag);
3196 		}
3197 		if (bump_rotor) {
3198 			if (args->agno == sagno)
3199 				mp->m_agfrotor = (mp->m_agfrotor + 1) %
3200 					(mp->m_sb.sb_agcount * rotorstep);
3201 			else
3202 				mp->m_agfrotor = (args->agno * rotorstep + 1) %
3203 					(mp->m_sb.sb_agcount * rotorstep);
3204 		}
3205 		break;
3206 	default:
3207 		ASSERT(0);
3208 		/* NOTREACHED */
3209 	}
3210 	if (args->agbno == NULLAGBLOCK)
3211 		args->fsbno = NULLFSBLOCK;
3212 	else {
3213 		args->fsbno = XFS_AGB_TO_FSB(mp, args->agno, args->agbno);
3214 #ifdef DEBUG
3215 		ASSERT(args->len >= args->minlen);
3216 		ASSERT(args->len <= args->maxlen);
3217 		ASSERT(args->agbno % args->alignment == 0);
3218 		XFS_AG_CHECK_DADDR(mp, XFS_FSB_TO_DADDR(mp, args->fsbno),
3219 			args->len);
3220 #endif
3221 
3222 	}
3223 	xfs_perag_put(args->pag);
3224 	return 0;
3225 error0:
3226 	xfs_perag_put(args->pag);
3227 	return error;
3228 }
3229 
3230 /* Ensure that the freelist is at full capacity. */
3231 int
xfs_free_extent_fix_freelist(struct xfs_trans * tp,xfs_agnumber_t agno,struct xfs_buf ** agbp)3232 xfs_free_extent_fix_freelist(
3233 	struct xfs_trans	*tp,
3234 	xfs_agnumber_t		agno,
3235 	struct xfs_buf		**agbp)
3236 {
3237 	struct xfs_alloc_arg	args;
3238 	int			error;
3239 
3240 	memset(&args, 0, sizeof(struct xfs_alloc_arg));
3241 	args.tp = tp;
3242 	args.mp = tp->t_mountp;
3243 	args.agno = agno;
3244 
3245 	/*
3246 	 * validate that the block number is legal - the enables us to detect
3247 	 * and handle a silent filesystem corruption rather than crashing.
3248 	 */
3249 	if (args.agno >= args.mp->m_sb.sb_agcount)
3250 		return -EFSCORRUPTED;
3251 
3252 	args.pag = xfs_perag_get(args.mp, args.agno);
3253 	ASSERT(args.pag);
3254 
3255 	error = xfs_alloc_fix_freelist(&args, XFS_ALLOC_FLAG_FREEING);
3256 	if (error)
3257 		goto out;
3258 
3259 	*agbp = args.agbp;
3260 out:
3261 	xfs_perag_put(args.pag);
3262 	return error;
3263 }
3264 
3265 /*
3266  * Free an extent.
3267  * Just break up the extent address and hand off to xfs_free_ag_extent
3268  * after fixing up the freelist.
3269  */
3270 int
__xfs_free_extent(struct xfs_trans * tp,xfs_fsblock_t bno,xfs_extlen_t len,const struct xfs_owner_info * oinfo,enum xfs_ag_resv_type type,bool skip_discard)3271 __xfs_free_extent(
3272 	struct xfs_trans		*tp,
3273 	xfs_fsblock_t			bno,
3274 	xfs_extlen_t			len,
3275 	const struct xfs_owner_info	*oinfo,
3276 	enum xfs_ag_resv_type		type,
3277 	bool				skip_discard)
3278 {
3279 	struct xfs_mount		*mp = tp->t_mountp;
3280 	struct xfs_buf			*agbp;
3281 	xfs_agnumber_t			agno = XFS_FSB_TO_AGNO(mp, bno);
3282 	xfs_agblock_t			agbno = XFS_FSB_TO_AGBNO(mp, bno);
3283 	struct xfs_agf			*agf;
3284 	int				error;
3285 	unsigned int			busy_flags = 0;
3286 
3287 	ASSERT(len != 0);
3288 	ASSERT(type != XFS_AG_RESV_AGFL);
3289 
3290 	if (XFS_TEST_ERROR(false, mp,
3291 			XFS_ERRTAG_FREE_EXTENT))
3292 		return -EIO;
3293 
3294 	error = xfs_free_extent_fix_freelist(tp, agno, &agbp);
3295 	if (error)
3296 		return error;
3297 	agf = agbp->b_addr;
3298 
3299 	if (XFS_IS_CORRUPT(mp, agbno >= mp->m_sb.sb_agblocks)) {
3300 		error = -EFSCORRUPTED;
3301 		goto err;
3302 	}
3303 
3304 	/* validate the extent size is legal now we have the agf locked */
3305 	if (XFS_IS_CORRUPT(mp, agbno + len > be32_to_cpu(agf->agf_length))) {
3306 		error = -EFSCORRUPTED;
3307 		goto err;
3308 	}
3309 
3310 	error = xfs_free_ag_extent(tp, agbp, agno, agbno, len, oinfo, type);
3311 	if (error)
3312 		goto err;
3313 
3314 	if (skip_discard)
3315 		busy_flags |= XFS_EXTENT_BUSY_SKIP_DISCARD;
3316 	xfs_extent_busy_insert(tp, agno, agbno, len, busy_flags);
3317 	return 0;
3318 
3319 err:
3320 	xfs_trans_brelse(tp, agbp);
3321 	return error;
3322 }
3323 
3324 struct xfs_alloc_query_range_info {
3325 	xfs_alloc_query_range_fn	fn;
3326 	void				*priv;
3327 };
3328 
3329 /* Format btree record and pass to our callback. */
3330 STATIC int
xfs_alloc_query_range_helper(struct xfs_btree_cur * cur,union xfs_btree_rec * rec,void * priv)3331 xfs_alloc_query_range_helper(
3332 	struct xfs_btree_cur		*cur,
3333 	union xfs_btree_rec		*rec,
3334 	void				*priv)
3335 {
3336 	struct xfs_alloc_query_range_info	*query = priv;
3337 	struct xfs_alloc_rec_incore		irec;
3338 
3339 	irec.ar_startblock = be32_to_cpu(rec->alloc.ar_startblock);
3340 	irec.ar_blockcount = be32_to_cpu(rec->alloc.ar_blockcount);
3341 	return query->fn(cur, &irec, query->priv);
3342 }
3343 
3344 /* Find all free space within a given range of blocks. */
3345 int
xfs_alloc_query_range(struct xfs_btree_cur * cur,struct xfs_alloc_rec_incore * low_rec,struct xfs_alloc_rec_incore * high_rec,xfs_alloc_query_range_fn fn,void * priv)3346 xfs_alloc_query_range(
3347 	struct xfs_btree_cur			*cur,
3348 	struct xfs_alloc_rec_incore		*low_rec,
3349 	struct xfs_alloc_rec_incore		*high_rec,
3350 	xfs_alloc_query_range_fn		fn,
3351 	void					*priv)
3352 {
3353 	union xfs_btree_irec			low_brec;
3354 	union xfs_btree_irec			high_brec;
3355 	struct xfs_alloc_query_range_info	query;
3356 
3357 	ASSERT(cur->bc_btnum == XFS_BTNUM_BNO);
3358 	low_brec.a = *low_rec;
3359 	high_brec.a = *high_rec;
3360 	query.priv = priv;
3361 	query.fn = fn;
3362 	return xfs_btree_query_range(cur, &low_brec, &high_brec,
3363 			xfs_alloc_query_range_helper, &query);
3364 }
3365 
3366 /* Find all free space records. */
3367 int
xfs_alloc_query_all(struct xfs_btree_cur * cur,xfs_alloc_query_range_fn fn,void * priv)3368 xfs_alloc_query_all(
3369 	struct xfs_btree_cur			*cur,
3370 	xfs_alloc_query_range_fn		fn,
3371 	void					*priv)
3372 {
3373 	struct xfs_alloc_query_range_info	query;
3374 
3375 	ASSERT(cur->bc_btnum == XFS_BTNUM_BNO);
3376 	query.priv = priv;
3377 	query.fn = fn;
3378 	return xfs_btree_query_all(cur, xfs_alloc_query_range_helper, &query);
3379 }
3380 
3381 /* Is there a record covering a given extent? */
3382 int
xfs_alloc_has_record(struct xfs_btree_cur * cur,xfs_agblock_t bno,xfs_extlen_t len,bool * exists)3383 xfs_alloc_has_record(
3384 	struct xfs_btree_cur	*cur,
3385 	xfs_agblock_t		bno,
3386 	xfs_extlen_t		len,
3387 	bool			*exists)
3388 {
3389 	union xfs_btree_irec	low;
3390 	union xfs_btree_irec	high;
3391 
3392 	memset(&low, 0, sizeof(low));
3393 	low.a.ar_startblock = bno;
3394 	memset(&high, 0xFF, sizeof(high));
3395 	high.a.ar_startblock = bno + len - 1;
3396 
3397 	return xfs_btree_has_record(cur, &low, &high, exists);
3398 }
3399 
3400 /*
3401  * Walk all the blocks in the AGFL.  The @walk_fn can return any negative
3402  * error code or XFS_ITER_*.
3403  */
3404 int
xfs_agfl_walk(struct xfs_mount * mp,struct xfs_agf * agf,struct xfs_buf * agflbp,xfs_agfl_walk_fn walk_fn,void * priv)3405 xfs_agfl_walk(
3406 	struct xfs_mount	*mp,
3407 	struct xfs_agf		*agf,
3408 	struct xfs_buf		*agflbp,
3409 	xfs_agfl_walk_fn	walk_fn,
3410 	void			*priv)
3411 {
3412 	__be32			*agfl_bno;
3413 	unsigned int		i;
3414 	int			error;
3415 
3416 	agfl_bno = xfs_buf_to_agfl_bno(agflbp);
3417 	i = be32_to_cpu(agf->agf_flfirst);
3418 
3419 	/* Nothing to walk in an empty AGFL. */
3420 	if (agf->agf_flcount == cpu_to_be32(0))
3421 		return 0;
3422 
3423 	/* Otherwise, walk from first to last, wrapping as needed. */
3424 	for (;;) {
3425 		error = walk_fn(mp, be32_to_cpu(agfl_bno[i]), priv);
3426 		if (error)
3427 			return error;
3428 		if (i == be32_to_cpu(agf->agf_fllast))
3429 			break;
3430 		if (++i == xfs_agfl_size(mp))
3431 			i = 0;
3432 	}
3433 
3434 	return 0;
3435 }
3436