xref: /openbmc/linux/fs/xfs/xfs_fsops.c (revision a1e58bbd)
1 /*
2  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
3  * All Rights Reserved.
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License as
7  * published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it would be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write the Free Software Foundation,
16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17  */
18 #include "xfs.h"
19 #include "xfs_fs.h"
20 #include "xfs_types.h"
21 #include "xfs_bit.h"
22 #include "xfs_inum.h"
23 #include "xfs_log.h"
24 #include "xfs_trans.h"
25 #include "xfs_sb.h"
26 #include "xfs_ag.h"
27 #include "xfs_dir2.h"
28 #include "xfs_dmapi.h"
29 #include "xfs_mount.h"
30 #include "xfs_bmap_btree.h"
31 #include "xfs_alloc_btree.h"
32 #include "xfs_ialloc_btree.h"
33 #include "xfs_dir2_sf.h"
34 #include "xfs_attr_sf.h"
35 #include "xfs_dinode.h"
36 #include "xfs_inode.h"
37 #include "xfs_inode_item.h"
38 #include "xfs_btree.h"
39 #include "xfs_error.h"
40 #include "xfs_alloc.h"
41 #include "xfs_ialloc.h"
42 #include "xfs_fsops.h"
43 #include "xfs_itable.h"
44 #include "xfs_trans_space.h"
45 #include "xfs_rtalloc.h"
46 #include "xfs_rw.h"
47 #include "xfs_filestream.h"
48 
49 /*
50  * File system operations
51  */
52 
53 int
54 xfs_fs_geometry(
55 	xfs_mount_t		*mp,
56 	xfs_fsop_geom_t		*geo,
57 	int			new_version)
58 {
59 	geo->blocksize = mp->m_sb.sb_blocksize;
60 	geo->rtextsize = mp->m_sb.sb_rextsize;
61 	geo->agblocks = mp->m_sb.sb_agblocks;
62 	geo->agcount = mp->m_sb.sb_agcount;
63 	geo->logblocks = mp->m_sb.sb_logblocks;
64 	geo->sectsize = mp->m_sb.sb_sectsize;
65 	geo->inodesize = mp->m_sb.sb_inodesize;
66 	geo->imaxpct = mp->m_sb.sb_imax_pct;
67 	geo->datablocks = mp->m_sb.sb_dblocks;
68 	geo->rtblocks = mp->m_sb.sb_rblocks;
69 	geo->rtextents = mp->m_sb.sb_rextents;
70 	geo->logstart = mp->m_sb.sb_logstart;
71 	ASSERT(sizeof(geo->uuid)==sizeof(mp->m_sb.sb_uuid));
72 	memcpy(geo->uuid, &mp->m_sb.sb_uuid, sizeof(mp->m_sb.sb_uuid));
73 	if (new_version >= 2) {
74 		geo->sunit = mp->m_sb.sb_unit;
75 		geo->swidth = mp->m_sb.sb_width;
76 	}
77 	if (new_version >= 3) {
78 		geo->version = XFS_FSOP_GEOM_VERSION;
79 		geo->flags =
80 			(xfs_sb_version_hasattr(&mp->m_sb) ?
81 				XFS_FSOP_GEOM_FLAGS_ATTR : 0) |
82 			(xfs_sb_version_hasnlink(&mp->m_sb) ?
83 				XFS_FSOP_GEOM_FLAGS_NLINK : 0) |
84 			(xfs_sb_version_hasquota(&mp->m_sb) ?
85 				XFS_FSOP_GEOM_FLAGS_QUOTA : 0) |
86 			(xfs_sb_version_hasalign(&mp->m_sb) ?
87 				XFS_FSOP_GEOM_FLAGS_IALIGN : 0) |
88 			(xfs_sb_version_hasdalign(&mp->m_sb) ?
89 				XFS_FSOP_GEOM_FLAGS_DALIGN : 0) |
90 			(xfs_sb_version_hasshared(&mp->m_sb) ?
91 				XFS_FSOP_GEOM_FLAGS_SHARED : 0) |
92 			(xfs_sb_version_hasextflgbit(&mp->m_sb) ?
93 				XFS_FSOP_GEOM_FLAGS_EXTFLG : 0) |
94 			(xfs_sb_version_hasdirv2(&mp->m_sb) ?
95 				XFS_FSOP_GEOM_FLAGS_DIRV2 : 0) |
96 			(xfs_sb_version_hassector(&mp->m_sb) ?
97 				XFS_FSOP_GEOM_FLAGS_SECTOR : 0) |
98 			(xfs_sb_version_haslazysbcount(&mp->m_sb) ?
99 				XFS_FSOP_GEOM_FLAGS_LAZYSB : 0) |
100 			(xfs_sb_version_hasattr2(&mp->m_sb) ?
101 				XFS_FSOP_GEOM_FLAGS_ATTR2 : 0);
102 		geo->logsectsize = xfs_sb_version_hassector(&mp->m_sb) ?
103 				mp->m_sb.sb_logsectsize : BBSIZE;
104 		geo->rtsectsize = mp->m_sb.sb_blocksize;
105 		geo->dirblocksize = mp->m_dirblksize;
106 	}
107 	if (new_version >= 4) {
108 		geo->flags |=
109 			(xfs_sb_version_haslogv2(&mp->m_sb) ?
110 				XFS_FSOP_GEOM_FLAGS_LOGV2 : 0);
111 		geo->logsunit = mp->m_sb.sb_logsunit;
112 	}
113 	return 0;
114 }
115 
116 static int
117 xfs_growfs_data_private(
118 	xfs_mount_t		*mp,		/* mount point for filesystem */
119 	xfs_growfs_data_t	*in)		/* growfs data input struct */
120 {
121 	xfs_agf_t		*agf;
122 	xfs_agi_t		*agi;
123 	xfs_agnumber_t		agno;
124 	xfs_extlen_t		agsize;
125 	xfs_extlen_t		tmpsize;
126 	xfs_alloc_rec_t		*arec;
127 	xfs_btree_sblock_t	*block;
128 	xfs_buf_t		*bp;
129 	int			bucket;
130 	int			dpct;
131 	int			error;
132 	xfs_agnumber_t		nagcount;
133 	xfs_agnumber_t		nagimax = 0;
134 	xfs_rfsblock_t		nb, nb_mod;
135 	xfs_rfsblock_t		new;
136 	xfs_rfsblock_t		nfree;
137 	xfs_agnumber_t		oagcount;
138 	int			pct;
139 	xfs_trans_t		*tp;
140 
141 	nb = in->newblocks;
142 	pct = in->imaxpct;
143 	if (nb < mp->m_sb.sb_dblocks || pct < 0 || pct > 100)
144 		return XFS_ERROR(EINVAL);
145 	if ((error = xfs_sb_validate_fsb_count(&mp->m_sb, nb)))
146 		return error;
147 	dpct = pct - mp->m_sb.sb_imax_pct;
148 	error = xfs_read_buf(mp, mp->m_ddev_targp,
149 			XFS_FSB_TO_BB(mp, nb) - XFS_FSS_TO_BB(mp, 1),
150 			XFS_FSS_TO_BB(mp, 1), 0, &bp);
151 	if (error)
152 		return error;
153 	ASSERT(bp);
154 	xfs_buf_relse(bp);
155 
156 	new = nb;	/* use new as a temporary here */
157 	nb_mod = do_div(new, mp->m_sb.sb_agblocks);
158 	nagcount = new + (nb_mod != 0);
159 	if (nb_mod && nb_mod < XFS_MIN_AG_BLOCKS) {
160 		nagcount--;
161 		nb = nagcount * mp->m_sb.sb_agblocks;
162 		if (nb < mp->m_sb.sb_dblocks)
163 			return XFS_ERROR(EINVAL);
164 	}
165 	new = nb - mp->m_sb.sb_dblocks;
166 	oagcount = mp->m_sb.sb_agcount;
167 	if (nagcount > oagcount) {
168 		xfs_filestream_flush(mp);
169 		down_write(&mp->m_peraglock);
170 		mp->m_perag = kmem_realloc(mp->m_perag,
171 			sizeof(xfs_perag_t) * nagcount,
172 			sizeof(xfs_perag_t) * oagcount,
173 			KM_SLEEP);
174 		memset(&mp->m_perag[oagcount], 0,
175 			(nagcount - oagcount) * sizeof(xfs_perag_t));
176 		mp->m_flags |= XFS_MOUNT_32BITINODES;
177 		nagimax = xfs_initialize_perag(mp, nagcount);
178 		up_write(&mp->m_peraglock);
179 	}
180 	tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFS);
181 	tp->t_flags |= XFS_TRANS_RESERVE;
182 	if ((error = xfs_trans_reserve(tp, XFS_GROWFS_SPACE_RES(mp),
183 			XFS_GROWDATA_LOG_RES(mp), 0, 0, 0))) {
184 		xfs_trans_cancel(tp, 0);
185 		return error;
186 	}
187 
188 	nfree = 0;
189 	for (agno = nagcount - 1; agno >= oagcount; agno--, new -= agsize) {
190 		/*
191 		 * AG freelist header block
192 		 */
193 		bp = xfs_buf_get(mp->m_ddev_targp,
194 				  XFS_AG_DADDR(mp, agno, XFS_AGF_DADDR(mp)),
195 				  XFS_FSS_TO_BB(mp, 1), 0);
196 		agf = XFS_BUF_TO_AGF(bp);
197 		memset(agf, 0, mp->m_sb.sb_sectsize);
198 		agf->agf_magicnum = cpu_to_be32(XFS_AGF_MAGIC);
199 		agf->agf_versionnum = cpu_to_be32(XFS_AGF_VERSION);
200 		agf->agf_seqno = cpu_to_be32(agno);
201 		if (agno == nagcount - 1)
202 			agsize =
203 				nb -
204 				(agno * (xfs_rfsblock_t)mp->m_sb.sb_agblocks);
205 		else
206 			agsize = mp->m_sb.sb_agblocks;
207 		agf->agf_length = cpu_to_be32(agsize);
208 		agf->agf_roots[XFS_BTNUM_BNOi] = cpu_to_be32(XFS_BNO_BLOCK(mp));
209 		agf->agf_roots[XFS_BTNUM_CNTi] = cpu_to_be32(XFS_CNT_BLOCK(mp));
210 		agf->agf_levels[XFS_BTNUM_BNOi] = cpu_to_be32(1);
211 		agf->agf_levels[XFS_BTNUM_CNTi] = cpu_to_be32(1);
212 		agf->agf_flfirst = 0;
213 		agf->agf_fllast = cpu_to_be32(XFS_AGFL_SIZE(mp) - 1);
214 		agf->agf_flcount = 0;
215 		tmpsize = agsize - XFS_PREALLOC_BLOCKS(mp);
216 		agf->agf_freeblks = cpu_to_be32(tmpsize);
217 		agf->agf_longest = cpu_to_be32(tmpsize);
218 		error = xfs_bwrite(mp, bp);
219 		if (error) {
220 			goto error0;
221 		}
222 		/*
223 		 * AG inode header block
224 		 */
225 		bp = xfs_buf_get(mp->m_ddev_targp,
226 				  XFS_AG_DADDR(mp, agno, XFS_AGI_DADDR(mp)),
227 				  XFS_FSS_TO_BB(mp, 1), 0);
228 		agi = XFS_BUF_TO_AGI(bp);
229 		memset(agi, 0, mp->m_sb.sb_sectsize);
230 		agi->agi_magicnum = cpu_to_be32(XFS_AGI_MAGIC);
231 		agi->agi_versionnum = cpu_to_be32(XFS_AGI_VERSION);
232 		agi->agi_seqno = cpu_to_be32(agno);
233 		agi->agi_length = cpu_to_be32(agsize);
234 		agi->agi_count = 0;
235 		agi->agi_root = cpu_to_be32(XFS_IBT_BLOCK(mp));
236 		agi->agi_level = cpu_to_be32(1);
237 		agi->agi_freecount = 0;
238 		agi->agi_newino = cpu_to_be32(NULLAGINO);
239 		agi->agi_dirino = cpu_to_be32(NULLAGINO);
240 		for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++)
241 			agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
242 		error = xfs_bwrite(mp, bp);
243 		if (error) {
244 			goto error0;
245 		}
246 		/*
247 		 * BNO btree root block
248 		 */
249 		bp = xfs_buf_get(mp->m_ddev_targp,
250 			XFS_AGB_TO_DADDR(mp, agno, XFS_BNO_BLOCK(mp)),
251 			BTOBB(mp->m_sb.sb_blocksize), 0);
252 		block = XFS_BUF_TO_SBLOCK(bp);
253 		memset(block, 0, mp->m_sb.sb_blocksize);
254 		block->bb_magic = cpu_to_be32(XFS_ABTB_MAGIC);
255 		block->bb_level = 0;
256 		block->bb_numrecs = cpu_to_be16(1);
257 		block->bb_leftsib = cpu_to_be32(NULLAGBLOCK);
258 		block->bb_rightsib = cpu_to_be32(NULLAGBLOCK);
259 		arec = XFS_BTREE_REC_ADDR(xfs_alloc, block, 1);
260 		arec->ar_startblock = cpu_to_be32(XFS_PREALLOC_BLOCKS(mp));
261 		arec->ar_blockcount = cpu_to_be32(
262 			agsize - be32_to_cpu(arec->ar_startblock));
263 		error = xfs_bwrite(mp, bp);
264 		if (error) {
265 			goto error0;
266 		}
267 		/*
268 		 * CNT btree root block
269 		 */
270 		bp = xfs_buf_get(mp->m_ddev_targp,
271 			XFS_AGB_TO_DADDR(mp, agno, XFS_CNT_BLOCK(mp)),
272 			BTOBB(mp->m_sb.sb_blocksize), 0);
273 		block = XFS_BUF_TO_SBLOCK(bp);
274 		memset(block, 0, mp->m_sb.sb_blocksize);
275 		block->bb_magic = cpu_to_be32(XFS_ABTC_MAGIC);
276 		block->bb_level = 0;
277 		block->bb_numrecs = cpu_to_be16(1);
278 		block->bb_leftsib = cpu_to_be32(NULLAGBLOCK);
279 		block->bb_rightsib = cpu_to_be32(NULLAGBLOCK);
280 		arec = XFS_BTREE_REC_ADDR(xfs_alloc, block, 1);
281 		arec->ar_startblock = cpu_to_be32(XFS_PREALLOC_BLOCKS(mp));
282 		arec->ar_blockcount = cpu_to_be32(
283 			agsize - be32_to_cpu(arec->ar_startblock));
284 		nfree += be32_to_cpu(arec->ar_blockcount);
285 		error = xfs_bwrite(mp, bp);
286 		if (error) {
287 			goto error0;
288 		}
289 		/*
290 		 * INO btree root block
291 		 */
292 		bp = xfs_buf_get(mp->m_ddev_targp,
293 			XFS_AGB_TO_DADDR(mp, agno, XFS_IBT_BLOCK(mp)),
294 			BTOBB(mp->m_sb.sb_blocksize), 0);
295 		block = XFS_BUF_TO_SBLOCK(bp);
296 		memset(block, 0, mp->m_sb.sb_blocksize);
297 		block->bb_magic = cpu_to_be32(XFS_IBT_MAGIC);
298 		block->bb_level = 0;
299 		block->bb_numrecs = 0;
300 		block->bb_leftsib = cpu_to_be32(NULLAGBLOCK);
301 		block->bb_rightsib = cpu_to_be32(NULLAGBLOCK);
302 		error = xfs_bwrite(mp, bp);
303 		if (error) {
304 			goto error0;
305 		}
306 	}
307 	xfs_trans_agblocks_delta(tp, nfree);
308 	/*
309 	 * There are new blocks in the old last a.g.
310 	 */
311 	if (new) {
312 		/*
313 		 * Change the agi length.
314 		 */
315 		error = xfs_ialloc_read_agi(mp, tp, agno, &bp);
316 		if (error) {
317 			goto error0;
318 		}
319 		ASSERT(bp);
320 		agi = XFS_BUF_TO_AGI(bp);
321 		be32_add_cpu(&agi->agi_length, new);
322 		ASSERT(nagcount == oagcount ||
323 		       be32_to_cpu(agi->agi_length) == mp->m_sb.sb_agblocks);
324 		xfs_ialloc_log_agi(tp, bp, XFS_AGI_LENGTH);
325 		/*
326 		 * Change agf length.
327 		 */
328 		error = xfs_alloc_read_agf(mp, tp, agno, 0, &bp);
329 		if (error) {
330 			goto error0;
331 		}
332 		ASSERT(bp);
333 		agf = XFS_BUF_TO_AGF(bp);
334 		be32_add_cpu(&agf->agf_length, new);
335 		ASSERT(be32_to_cpu(agf->agf_length) ==
336 		       be32_to_cpu(agi->agi_length));
337 		xfs_alloc_log_agf(tp, bp, XFS_AGF_LENGTH);
338 		/*
339 		 * Free the new space.
340 		 */
341 		error = xfs_free_extent(tp, XFS_AGB_TO_FSB(mp, agno,
342 			be32_to_cpu(agf->agf_length) - new), new);
343 		if (error) {
344 			goto error0;
345 		}
346 	}
347 	if (nagcount > oagcount)
348 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_AGCOUNT, nagcount - oagcount);
349 	if (nb > mp->m_sb.sb_dblocks)
350 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_DBLOCKS,
351 				 nb - mp->m_sb.sb_dblocks);
352 	if (nfree)
353 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, nfree);
354 	if (dpct)
355 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_IMAXPCT, dpct);
356 	error = xfs_trans_commit(tp, 0);
357 	if (error) {
358 		return error;
359 	}
360 	/* New allocation groups fully initialized, so update mount struct */
361 	if (nagimax)
362 		mp->m_maxagi = nagimax;
363 	if (mp->m_sb.sb_imax_pct) {
364 		__uint64_t icount = mp->m_sb.sb_dblocks * mp->m_sb.sb_imax_pct;
365 		do_div(icount, 100);
366 		mp->m_maxicount = icount << mp->m_sb.sb_inopblog;
367 	} else
368 		mp->m_maxicount = 0;
369 	for (agno = 1; agno < nagcount; agno++) {
370 		error = xfs_read_buf(mp, mp->m_ddev_targp,
371 				  XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
372 				  XFS_FSS_TO_BB(mp, 1), 0, &bp);
373 		if (error) {
374 			xfs_fs_cmn_err(CE_WARN, mp,
375 			"error %d reading secondary superblock for ag %d",
376 				error, agno);
377 			break;
378 		}
379 		xfs_sb_to_disk(XFS_BUF_TO_SBP(bp), &mp->m_sb, XFS_SB_ALL_BITS);
380 		/*
381 		 * If we get an error writing out the alternate superblocks,
382 		 * just issue a warning and continue.  The real work is
383 		 * already done and committed.
384 		 */
385 		if (!(error = xfs_bwrite(mp, bp))) {
386 			continue;
387 		} else {
388 			xfs_fs_cmn_err(CE_WARN, mp,
389 		"write error %d updating secondary superblock for ag %d",
390 				error, agno);
391 			break; /* no point in continuing */
392 		}
393 	}
394 	return 0;
395 
396  error0:
397 	xfs_trans_cancel(tp, XFS_TRANS_ABORT);
398 	return error;
399 }
400 
401 static int
402 xfs_growfs_log_private(
403 	xfs_mount_t		*mp,	/* mount point for filesystem */
404 	xfs_growfs_log_t	*in)	/* growfs log input struct */
405 {
406 	xfs_extlen_t		nb;
407 
408 	nb = in->newblocks;
409 	if (nb < XFS_MIN_LOG_BLOCKS || nb < XFS_B_TO_FSB(mp, XFS_MIN_LOG_BYTES))
410 		return XFS_ERROR(EINVAL);
411 	if (nb == mp->m_sb.sb_logblocks &&
412 	    in->isint == (mp->m_sb.sb_logstart != 0))
413 		return XFS_ERROR(EINVAL);
414 	/*
415 	 * Moving the log is hard, need new interfaces to sync
416 	 * the log first, hold off all activity while moving it.
417 	 * Can have shorter or longer log in the same space,
418 	 * or transform internal to external log or vice versa.
419 	 */
420 	return XFS_ERROR(ENOSYS);
421 }
422 
423 /*
424  * protected versions of growfs function acquire and release locks on the mount
425  * point - exported through ioctls: XFS_IOC_FSGROWFSDATA, XFS_IOC_FSGROWFSLOG,
426  * XFS_IOC_FSGROWFSRT
427  */
428 
429 
430 int
431 xfs_growfs_data(
432 	xfs_mount_t		*mp,
433 	xfs_growfs_data_t	*in)
434 {
435 	int error;
436 	if (!mutex_trylock(&mp->m_growlock))
437 		return XFS_ERROR(EWOULDBLOCK);
438 	error = xfs_growfs_data_private(mp, in);
439 	mutex_unlock(&mp->m_growlock);
440 	return error;
441 }
442 
443 int
444 xfs_growfs_log(
445 	xfs_mount_t		*mp,
446 	xfs_growfs_log_t	*in)
447 {
448 	int error;
449 	if (!mutex_trylock(&mp->m_growlock))
450 		return XFS_ERROR(EWOULDBLOCK);
451 	error = xfs_growfs_log_private(mp, in);
452 	mutex_unlock(&mp->m_growlock);
453 	return error;
454 }
455 
456 /*
457  * exported through ioctl XFS_IOC_FSCOUNTS
458  */
459 
460 int
461 xfs_fs_counts(
462 	xfs_mount_t		*mp,
463 	xfs_fsop_counts_t	*cnt)
464 {
465 	xfs_icsb_sync_counters_flags(mp, XFS_ICSB_LAZY_COUNT);
466 	spin_lock(&mp->m_sb_lock);
467 	cnt->freedata = mp->m_sb.sb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
468 	cnt->freertx = mp->m_sb.sb_frextents;
469 	cnt->freeino = mp->m_sb.sb_ifree;
470 	cnt->allocino = mp->m_sb.sb_icount;
471 	spin_unlock(&mp->m_sb_lock);
472 	return 0;
473 }
474 
475 /*
476  * exported through ioctl XFS_IOC_SET_RESBLKS & XFS_IOC_GET_RESBLKS
477  *
478  * xfs_reserve_blocks is called to set m_resblks
479  * in the in-core mount table. The number of unused reserved blocks
480  * is kept in m_resblks_avail.
481  *
482  * Reserve the requested number of blocks if available. Otherwise return
483  * as many as possible to satisfy the request. The actual number
484  * reserved are returned in outval
485  *
486  * A null inval pointer indicates that only the current reserved blocks
487  * available  should  be returned no settings are changed.
488  */
489 
490 int
491 xfs_reserve_blocks(
492 	xfs_mount_t             *mp,
493 	__uint64_t              *inval,
494 	xfs_fsop_resblks_t      *outval)
495 {
496 	__int64_t		lcounter, delta, fdblks_delta;
497 	__uint64_t		request;
498 
499 	/* If inval is null, report current values and return */
500 	if (inval == (__uint64_t *)NULL) {
501 		if (!outval)
502 			return EINVAL;
503 		outval->resblks = mp->m_resblks;
504 		outval->resblks_avail = mp->m_resblks_avail;
505 		return 0;
506 	}
507 
508 	request = *inval;
509 
510 	/*
511 	 * With per-cpu counters, this becomes an interesting
512 	 * problem. we needto work out if we are freeing or allocation
513 	 * blocks first, then we can do the modification as necessary.
514 	 *
515 	 * We do this under the m_sb_lock so that if we are near
516 	 * ENOSPC, we will hold out any changes while we work out
517 	 * what to do. This means that the amount of free space can
518 	 * change while we do this, so we need to retry if we end up
519 	 * trying to reserve more space than is available.
520 	 *
521 	 * We also use the xfs_mod_incore_sb() interface so that we
522 	 * don't have to care about whether per cpu counter are
523 	 * enabled, disabled or even compiled in....
524 	 */
525 retry:
526 	spin_lock(&mp->m_sb_lock);
527 	xfs_icsb_sync_counters_flags(mp, XFS_ICSB_SB_LOCKED);
528 
529 	/*
530 	 * If our previous reservation was larger than the current value,
531 	 * then move any unused blocks back to the free pool.
532 	 */
533 	fdblks_delta = 0;
534 	if (mp->m_resblks > request) {
535 		lcounter = mp->m_resblks_avail - request;
536 		if (lcounter  > 0) {		/* release unused blocks */
537 			fdblks_delta = lcounter;
538 			mp->m_resblks_avail -= lcounter;
539 		}
540 		mp->m_resblks = request;
541 	} else {
542 		__int64_t	free;
543 
544 		free =  mp->m_sb.sb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
545 		if (!free)
546 			goto out; /* ENOSPC and fdblks_delta = 0 */
547 
548 		delta = request - mp->m_resblks;
549 		lcounter = free - delta;
550 		if (lcounter < 0) {
551 			/* We can't satisfy the request, just get what we can */
552 			mp->m_resblks += free;
553 			mp->m_resblks_avail += free;
554 			fdblks_delta = -free;
555 			mp->m_sb.sb_fdblocks = XFS_ALLOC_SET_ASIDE(mp);
556 		} else {
557 			fdblks_delta = -delta;
558 			mp->m_sb.sb_fdblocks =
559 				lcounter + XFS_ALLOC_SET_ASIDE(mp);
560 			mp->m_resblks = request;
561 			mp->m_resblks_avail += delta;
562 		}
563 	}
564 out:
565 	if (outval) {
566 		outval->resblks = mp->m_resblks;
567 		outval->resblks_avail = mp->m_resblks_avail;
568 	}
569 	spin_unlock(&mp->m_sb_lock);
570 
571 	if (fdblks_delta) {
572 		/*
573 		 * If we are putting blocks back here, m_resblks_avail is
574 		 * already at it's max so this will put it in the free pool.
575 		 *
576 		 * If we need space, we'll either succeed in getting it
577 		 * from the free block count or we'll get an enospc. If
578 		 * we get a ENOSPC, it means things changed while we were
579 		 * calculating fdblks_delta and so we should try again to
580 		 * see if there is anything left to reserve.
581 		 *
582 		 * Don't set the reserved flag here - we don't want to reserve
583 		 * the extra reserve blocks from the reserve.....
584 		 */
585 		int error;
586 		error = xfs_mod_incore_sb(mp, XFS_SBS_FDBLOCKS, fdblks_delta, 0);
587 		if (error == ENOSPC)
588 			goto retry;
589 	}
590 
591 	return 0;
592 }
593 
594 void
595 xfs_fs_log_dummy(
596 	xfs_mount_t	*mp)
597 {
598 	xfs_trans_t	*tp;
599 	xfs_inode_t	*ip;
600 
601 	tp = _xfs_trans_alloc(mp, XFS_TRANS_DUMMY1);
602 	if (xfs_trans_reserve(tp, 0, XFS_ICHANGE_LOG_RES(mp), 0, 0, 0)) {
603 		xfs_trans_cancel(tp, 0);
604 		return;
605 	}
606 
607 	ip = mp->m_rootip;
608 	xfs_ilock(ip, XFS_ILOCK_EXCL);
609 
610 	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
611 	xfs_trans_ihold(tp, ip);
612 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
613 	xfs_trans_set_sync(tp);
614 	xfs_trans_commit(tp, 0);
615 
616 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
617 }
618 
619 int
620 xfs_fs_goingdown(
621 	xfs_mount_t	*mp,
622 	__uint32_t	inflags)
623 {
624 	switch (inflags) {
625 	case XFS_FSOP_GOING_FLAGS_DEFAULT: {
626 		struct super_block *sb = freeze_bdev(mp->m_super->s_bdev);
627 
628 		if (sb && !IS_ERR(sb)) {
629 			xfs_force_shutdown(mp, SHUTDOWN_FORCE_UMOUNT);
630 			thaw_bdev(sb->s_bdev, sb);
631 		}
632 
633 		break;
634 	}
635 	case XFS_FSOP_GOING_FLAGS_LOGFLUSH:
636 		xfs_force_shutdown(mp, SHUTDOWN_FORCE_UMOUNT);
637 		break;
638 	case XFS_FSOP_GOING_FLAGS_NOLOGFLUSH:
639 		xfs_force_shutdown(mp,
640 				SHUTDOWN_FORCE_UMOUNT | SHUTDOWN_LOG_IO_ERROR);
641 		break;
642 	default:
643 		return XFS_ERROR(EINVAL);
644 	}
645 
646 	return 0;
647 }
648