xref: /openbmc/linux/fs/xfs/libxfs/xfs_sb.c (revision b96fc2f3)
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_shared.h"
21 #include "xfs_format.h"
22 #include "xfs_log_format.h"
23 #include "xfs_trans_resv.h"
24 #include "xfs_bit.h"
25 #include "xfs_sb.h"
26 #include "xfs_mount.h"
27 #include "xfs_inode.h"
28 #include "xfs_ialloc.h"
29 #include "xfs_alloc.h"
30 #include "xfs_error.h"
31 #include "xfs_trace.h"
32 #include "xfs_cksum.h"
33 #include "xfs_trans.h"
34 #include "xfs_buf_item.h"
35 #include "xfs_bmap_btree.h"
36 #include "xfs_alloc_btree.h"
37 #include "xfs_ialloc_btree.h"
38 
39 /*
40  * Physical superblock buffer manipulations. Shared with libxfs in userspace.
41  */
42 
43 /*
44  * Reference counting access wrappers to the perag structures.
45  * Because we never free per-ag structures, the only thing we
46  * have to protect against changes is the tree structure itself.
47  */
48 struct xfs_perag *
49 xfs_perag_get(
50 	struct xfs_mount	*mp,
51 	xfs_agnumber_t		agno)
52 {
53 	struct xfs_perag	*pag;
54 	int			ref = 0;
55 
56 	rcu_read_lock();
57 	pag = radix_tree_lookup(&mp->m_perag_tree, agno);
58 	if (pag) {
59 		ASSERT(atomic_read(&pag->pag_ref) >= 0);
60 		ref = atomic_inc_return(&pag->pag_ref);
61 	}
62 	rcu_read_unlock();
63 	trace_xfs_perag_get(mp, agno, ref, _RET_IP_);
64 	return pag;
65 }
66 
67 /*
68  * search from @first to find the next perag with the given tag set.
69  */
70 struct xfs_perag *
71 xfs_perag_get_tag(
72 	struct xfs_mount	*mp,
73 	xfs_agnumber_t		first,
74 	int			tag)
75 {
76 	struct xfs_perag	*pag;
77 	int			found;
78 	int			ref;
79 
80 	rcu_read_lock();
81 	found = radix_tree_gang_lookup_tag(&mp->m_perag_tree,
82 					(void **)&pag, first, 1, tag);
83 	if (found <= 0) {
84 		rcu_read_unlock();
85 		return NULL;
86 	}
87 	ref = atomic_inc_return(&pag->pag_ref);
88 	rcu_read_unlock();
89 	trace_xfs_perag_get_tag(mp, pag->pag_agno, ref, _RET_IP_);
90 	return pag;
91 }
92 
93 void
94 xfs_perag_put(
95 	struct xfs_perag	*pag)
96 {
97 	int	ref;
98 
99 	ASSERT(atomic_read(&pag->pag_ref) > 0);
100 	ref = atomic_dec_return(&pag->pag_ref);
101 	trace_xfs_perag_put(pag->pag_mount, pag->pag_agno, ref, _RET_IP_);
102 }
103 
104 /*
105  * Check the validity of the SB found.
106  */
107 STATIC int
108 xfs_mount_validate_sb(
109 	xfs_mount_t	*mp,
110 	xfs_sb_t	*sbp,
111 	bool		check_inprogress,
112 	bool		check_version)
113 {
114 	if (sbp->sb_magicnum != XFS_SB_MAGIC) {
115 		xfs_warn(mp, "bad magic number");
116 		return -EWRONGFS;
117 	}
118 
119 
120 	if (!xfs_sb_good_version(sbp)) {
121 		xfs_warn(mp, "bad version");
122 		return -EWRONGFS;
123 	}
124 
125 	/*
126 	 * Version 5 superblock feature mask validation. Reject combinations the
127 	 * kernel cannot support up front before checking anything else. For
128 	 * write validation, we don't need to check feature masks.
129 	 */
130 	if (check_version && XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) {
131 		if (xfs_sb_has_compat_feature(sbp,
132 					XFS_SB_FEAT_COMPAT_UNKNOWN)) {
133 			xfs_warn(mp,
134 "Superblock has unknown compatible features (0x%x) enabled.",
135 				(sbp->sb_features_compat &
136 						XFS_SB_FEAT_COMPAT_UNKNOWN));
137 			xfs_warn(mp,
138 "Using a more recent kernel is recommended.");
139 		}
140 
141 		if (xfs_sb_has_ro_compat_feature(sbp,
142 					XFS_SB_FEAT_RO_COMPAT_UNKNOWN)) {
143 			xfs_alert(mp,
144 "Superblock has unknown read-only compatible features (0x%x) enabled.",
145 				(sbp->sb_features_ro_compat &
146 						XFS_SB_FEAT_RO_COMPAT_UNKNOWN));
147 			if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
148 				xfs_warn(mp,
149 "Attempted to mount read-only compatible filesystem read-write.");
150 				xfs_warn(mp,
151 "Filesystem can only be safely mounted read only.");
152 
153 				return -EINVAL;
154 			}
155 		}
156 		if (xfs_sb_has_incompat_feature(sbp,
157 					XFS_SB_FEAT_INCOMPAT_UNKNOWN)) {
158 			xfs_warn(mp,
159 "Superblock has unknown incompatible features (0x%x) enabled.",
160 				(sbp->sb_features_incompat &
161 						XFS_SB_FEAT_INCOMPAT_UNKNOWN));
162 			xfs_warn(mp,
163 "Filesystem can not be safely mounted by this kernel.");
164 			return -EINVAL;
165 		}
166 	}
167 
168 	if (xfs_sb_version_has_pquotino(sbp)) {
169 		if (sbp->sb_qflags & (XFS_OQUOTA_ENFD | XFS_OQUOTA_CHKD)) {
170 			xfs_notice(mp,
171 			   "Version 5 of Super block has XFS_OQUOTA bits.");
172 			return -EFSCORRUPTED;
173 		}
174 	} else if (sbp->sb_qflags & (XFS_PQUOTA_ENFD | XFS_GQUOTA_ENFD |
175 				XFS_PQUOTA_CHKD | XFS_GQUOTA_CHKD)) {
176 			xfs_notice(mp,
177 "Superblock earlier than Version 5 has XFS_[PQ]UOTA_{ENFD|CHKD} bits.");
178 			return -EFSCORRUPTED;
179 	}
180 
181 	/*
182 	 * Full inode chunks must be aligned to inode chunk size when
183 	 * sparse inodes are enabled to support the sparse chunk
184 	 * allocation algorithm and prevent overlapping inode records.
185 	 */
186 	if (xfs_sb_version_hassparseinodes(sbp)) {
187 		uint32_t	align;
188 
189 		align = XFS_INODES_PER_CHUNK * sbp->sb_inodesize
190 				>> sbp->sb_blocklog;
191 		if (sbp->sb_inoalignmt != align) {
192 			xfs_warn(mp,
193 "Inode block alignment (%u) must match chunk size (%u) for sparse inodes.",
194 				 sbp->sb_inoalignmt, align);
195 			return -EINVAL;
196 		}
197 	}
198 
199 	if (unlikely(
200 	    sbp->sb_logstart == 0 && mp->m_logdev_targp == mp->m_ddev_targp)) {
201 		xfs_warn(mp,
202 		"filesystem is marked as having an external log; "
203 		"specify logdev on the mount command line.");
204 		return -EINVAL;
205 	}
206 
207 	if (unlikely(
208 	    sbp->sb_logstart != 0 && mp->m_logdev_targp != mp->m_ddev_targp)) {
209 		xfs_warn(mp,
210 		"filesystem is marked as having an internal log; "
211 		"do not specify logdev on the mount command line.");
212 		return -EINVAL;
213 	}
214 
215 	/*
216 	 * More sanity checking.  Most of these were stolen directly from
217 	 * xfs_repair.
218 	 */
219 	if (unlikely(
220 	    sbp->sb_agcount <= 0					||
221 	    sbp->sb_sectsize < XFS_MIN_SECTORSIZE			||
222 	    sbp->sb_sectsize > XFS_MAX_SECTORSIZE			||
223 	    sbp->sb_sectlog < XFS_MIN_SECTORSIZE_LOG			||
224 	    sbp->sb_sectlog > XFS_MAX_SECTORSIZE_LOG			||
225 	    sbp->sb_sectsize != (1 << sbp->sb_sectlog)			||
226 	    sbp->sb_blocksize < XFS_MIN_BLOCKSIZE			||
227 	    sbp->sb_blocksize > XFS_MAX_BLOCKSIZE			||
228 	    sbp->sb_blocklog < XFS_MIN_BLOCKSIZE_LOG			||
229 	    sbp->sb_blocklog > XFS_MAX_BLOCKSIZE_LOG			||
230 	    sbp->sb_blocksize != (1 << sbp->sb_blocklog)		||
231 	    sbp->sb_dirblklog > XFS_MAX_BLOCKSIZE_LOG			||
232 	    sbp->sb_inodesize < XFS_DINODE_MIN_SIZE			||
233 	    sbp->sb_inodesize > XFS_DINODE_MAX_SIZE			||
234 	    sbp->sb_inodelog < XFS_DINODE_MIN_LOG			||
235 	    sbp->sb_inodelog > XFS_DINODE_MAX_LOG			||
236 	    sbp->sb_inodesize != (1 << sbp->sb_inodelog)		||
237 	    sbp->sb_logsunit > XLOG_MAX_RECORD_BSIZE			||
238 	    sbp->sb_inopblock != howmany(sbp->sb_blocksize,sbp->sb_inodesize) ||
239 	    (sbp->sb_blocklog - sbp->sb_inodelog != sbp->sb_inopblog)	||
240 	    (sbp->sb_rextsize * sbp->sb_blocksize > XFS_MAX_RTEXTSIZE)	||
241 	    (sbp->sb_rextsize * sbp->sb_blocksize < XFS_MIN_RTEXTSIZE)	||
242 	    (sbp->sb_imax_pct > 100 /* zero sb_imax_pct is valid */)	||
243 	    sbp->sb_dblocks == 0					||
244 	    sbp->sb_dblocks > XFS_MAX_DBLOCKS(sbp)			||
245 	    sbp->sb_dblocks < XFS_MIN_DBLOCKS(sbp)			||
246 	    sbp->sb_shared_vn != 0)) {
247 		xfs_notice(mp, "SB sanity check failed");
248 		return -EFSCORRUPTED;
249 	}
250 
251 	/*
252 	 * Until this is fixed only page-sized or smaller data blocks work.
253 	 */
254 	if (unlikely(sbp->sb_blocksize > PAGE_SIZE)) {
255 		xfs_warn(mp,
256 		"File system with blocksize %d bytes. "
257 		"Only pagesize (%ld) or less will currently work.",
258 				sbp->sb_blocksize, PAGE_SIZE);
259 		return -ENOSYS;
260 	}
261 
262 	/*
263 	 * Currently only very few inode sizes are supported.
264 	 */
265 	switch (sbp->sb_inodesize) {
266 	case 256:
267 	case 512:
268 	case 1024:
269 	case 2048:
270 		break;
271 	default:
272 		xfs_warn(mp, "inode size of %d bytes not supported",
273 				sbp->sb_inodesize);
274 		return -ENOSYS;
275 	}
276 
277 	if (xfs_sb_validate_fsb_count(sbp, sbp->sb_dblocks) ||
278 	    xfs_sb_validate_fsb_count(sbp, sbp->sb_rblocks)) {
279 		xfs_warn(mp,
280 		"file system too large to be mounted on this system.");
281 		return -EFBIG;
282 	}
283 
284 	if (check_inprogress && sbp->sb_inprogress) {
285 		xfs_warn(mp, "Offline file system operation in progress!");
286 		return -EFSCORRUPTED;
287 	}
288 	return 0;
289 }
290 
291 void
292 xfs_sb_quota_from_disk(struct xfs_sb *sbp)
293 {
294 	/*
295 	 * older mkfs doesn't initialize quota inodes to NULLFSINO. This
296 	 * leads to in-core values having two different values for a quota
297 	 * inode to be invalid: 0 and NULLFSINO. Change it to a single value
298 	 * NULLFSINO.
299 	 *
300 	 * Note that this change affect only the in-core values. These
301 	 * values are not written back to disk unless any quota information
302 	 * is written to the disk. Even in that case, sb_pquotino field is
303 	 * not written to disk unless the superblock supports pquotino.
304 	 */
305 	if (sbp->sb_uquotino == 0)
306 		sbp->sb_uquotino = NULLFSINO;
307 	if (sbp->sb_gquotino == 0)
308 		sbp->sb_gquotino = NULLFSINO;
309 	if (sbp->sb_pquotino == 0)
310 		sbp->sb_pquotino = NULLFSINO;
311 
312 	/*
313 	 * We need to do these manipilations only if we are working
314 	 * with an older version of on-disk superblock.
315 	 */
316 	if (xfs_sb_version_has_pquotino(sbp))
317 		return;
318 
319 	if (sbp->sb_qflags & XFS_OQUOTA_ENFD)
320 		sbp->sb_qflags |= (sbp->sb_qflags & XFS_PQUOTA_ACCT) ?
321 					XFS_PQUOTA_ENFD : XFS_GQUOTA_ENFD;
322 	if (sbp->sb_qflags & XFS_OQUOTA_CHKD)
323 		sbp->sb_qflags |= (sbp->sb_qflags & XFS_PQUOTA_ACCT) ?
324 					XFS_PQUOTA_CHKD : XFS_GQUOTA_CHKD;
325 	sbp->sb_qflags &= ~(XFS_OQUOTA_ENFD | XFS_OQUOTA_CHKD);
326 
327 	if (sbp->sb_qflags & XFS_PQUOTA_ACCT)  {
328 		/*
329 		 * In older version of superblock, on-disk superblock only
330 		 * has sb_gquotino, and in-core superblock has both sb_gquotino
331 		 * and sb_pquotino. But, only one of them is supported at any
332 		 * point of time. So, if PQUOTA is set in disk superblock,
333 		 * copy over sb_gquotino to sb_pquotino.
334 		 */
335 		sbp->sb_pquotino = sbp->sb_gquotino;
336 		sbp->sb_gquotino = NULLFSINO;
337 	}
338 }
339 
340 static void
341 __xfs_sb_from_disk(
342 	struct xfs_sb	*to,
343 	xfs_dsb_t	*from,
344 	bool		convert_xquota)
345 {
346 	to->sb_magicnum = be32_to_cpu(from->sb_magicnum);
347 	to->sb_blocksize = be32_to_cpu(from->sb_blocksize);
348 	to->sb_dblocks = be64_to_cpu(from->sb_dblocks);
349 	to->sb_rblocks = be64_to_cpu(from->sb_rblocks);
350 	to->sb_rextents = be64_to_cpu(from->sb_rextents);
351 	memcpy(&to->sb_uuid, &from->sb_uuid, sizeof(to->sb_uuid));
352 	to->sb_logstart = be64_to_cpu(from->sb_logstart);
353 	to->sb_rootino = be64_to_cpu(from->sb_rootino);
354 	to->sb_rbmino = be64_to_cpu(from->sb_rbmino);
355 	to->sb_rsumino = be64_to_cpu(from->sb_rsumino);
356 	to->sb_rextsize = be32_to_cpu(from->sb_rextsize);
357 	to->sb_agblocks = be32_to_cpu(from->sb_agblocks);
358 	to->sb_agcount = be32_to_cpu(from->sb_agcount);
359 	to->sb_rbmblocks = be32_to_cpu(from->sb_rbmblocks);
360 	to->sb_logblocks = be32_to_cpu(from->sb_logblocks);
361 	to->sb_versionnum = be16_to_cpu(from->sb_versionnum);
362 	to->sb_sectsize = be16_to_cpu(from->sb_sectsize);
363 	to->sb_inodesize = be16_to_cpu(from->sb_inodesize);
364 	to->sb_inopblock = be16_to_cpu(from->sb_inopblock);
365 	memcpy(&to->sb_fname, &from->sb_fname, sizeof(to->sb_fname));
366 	to->sb_blocklog = from->sb_blocklog;
367 	to->sb_sectlog = from->sb_sectlog;
368 	to->sb_inodelog = from->sb_inodelog;
369 	to->sb_inopblog = from->sb_inopblog;
370 	to->sb_agblklog = from->sb_agblklog;
371 	to->sb_rextslog = from->sb_rextslog;
372 	to->sb_inprogress = from->sb_inprogress;
373 	to->sb_imax_pct = from->sb_imax_pct;
374 	to->sb_icount = be64_to_cpu(from->sb_icount);
375 	to->sb_ifree = be64_to_cpu(from->sb_ifree);
376 	to->sb_fdblocks = be64_to_cpu(from->sb_fdblocks);
377 	to->sb_frextents = be64_to_cpu(from->sb_frextents);
378 	to->sb_uquotino = be64_to_cpu(from->sb_uquotino);
379 	to->sb_gquotino = be64_to_cpu(from->sb_gquotino);
380 	to->sb_qflags = be16_to_cpu(from->sb_qflags);
381 	to->sb_flags = from->sb_flags;
382 	to->sb_shared_vn = from->sb_shared_vn;
383 	to->sb_inoalignmt = be32_to_cpu(from->sb_inoalignmt);
384 	to->sb_unit = be32_to_cpu(from->sb_unit);
385 	to->sb_width = be32_to_cpu(from->sb_width);
386 	to->sb_dirblklog = from->sb_dirblklog;
387 	to->sb_logsectlog = from->sb_logsectlog;
388 	to->sb_logsectsize = be16_to_cpu(from->sb_logsectsize);
389 	to->sb_logsunit = be32_to_cpu(from->sb_logsunit);
390 	to->sb_features2 = be32_to_cpu(from->sb_features2);
391 	to->sb_bad_features2 = be32_to_cpu(from->sb_bad_features2);
392 	to->sb_features_compat = be32_to_cpu(from->sb_features_compat);
393 	to->sb_features_ro_compat = be32_to_cpu(from->sb_features_ro_compat);
394 	to->sb_features_incompat = be32_to_cpu(from->sb_features_incompat);
395 	to->sb_features_log_incompat =
396 				be32_to_cpu(from->sb_features_log_incompat);
397 	/* crc is only used on disk, not in memory; just init to 0 here. */
398 	to->sb_crc = 0;
399 	to->sb_spino_align = be32_to_cpu(from->sb_spino_align);
400 	to->sb_pquotino = be64_to_cpu(from->sb_pquotino);
401 	to->sb_lsn = be64_to_cpu(from->sb_lsn);
402 	/*
403 	 * sb_meta_uuid is only on disk if it differs from sb_uuid and the
404 	 * feature flag is set; if not set we keep it only in memory.
405 	 */
406 	if (xfs_sb_version_hasmetauuid(to))
407 		uuid_copy(&to->sb_meta_uuid, &from->sb_meta_uuid);
408 	else
409 		uuid_copy(&to->sb_meta_uuid, &from->sb_uuid);
410 	/* Convert on-disk flags to in-memory flags? */
411 	if (convert_xquota)
412 		xfs_sb_quota_from_disk(to);
413 }
414 
415 void
416 xfs_sb_from_disk(
417 	struct xfs_sb	*to,
418 	xfs_dsb_t	*from)
419 {
420 	__xfs_sb_from_disk(to, from, true);
421 }
422 
423 static void
424 xfs_sb_quota_to_disk(
425 	struct xfs_dsb	*to,
426 	struct xfs_sb	*from)
427 {
428 	__uint16_t	qflags = from->sb_qflags;
429 
430 	to->sb_uquotino = cpu_to_be64(from->sb_uquotino);
431 	if (xfs_sb_version_has_pquotino(from)) {
432 		to->sb_qflags = cpu_to_be16(from->sb_qflags);
433 		to->sb_gquotino = cpu_to_be64(from->sb_gquotino);
434 		to->sb_pquotino = cpu_to_be64(from->sb_pquotino);
435 		return;
436 	}
437 
438 	/*
439 	 * The in-core version of sb_qflags do not have XFS_OQUOTA_*
440 	 * flags, whereas the on-disk version does.  So, convert incore
441 	 * XFS_{PG}QUOTA_* flags to on-disk XFS_OQUOTA_* flags.
442 	 */
443 	qflags &= ~(XFS_PQUOTA_ENFD | XFS_PQUOTA_CHKD |
444 			XFS_GQUOTA_ENFD | XFS_GQUOTA_CHKD);
445 
446 	if (from->sb_qflags &
447 			(XFS_PQUOTA_ENFD | XFS_GQUOTA_ENFD))
448 		qflags |= XFS_OQUOTA_ENFD;
449 	if (from->sb_qflags &
450 			(XFS_PQUOTA_CHKD | XFS_GQUOTA_CHKD))
451 		qflags |= XFS_OQUOTA_CHKD;
452 	to->sb_qflags = cpu_to_be16(qflags);
453 
454 	/*
455 	 * GQUOTINO and PQUOTINO cannot be used together in versions
456 	 * of superblock that do not have pquotino. from->sb_flags
457 	 * tells us which quota is active and should be copied to
458 	 * disk. If neither are active, we should NULL the inode.
459 	 *
460 	 * In all cases, the separate pquotino must remain 0 because it
461 	 * it beyond the "end" of the valid non-pquotino superblock.
462 	 */
463 	if (from->sb_qflags & XFS_GQUOTA_ACCT)
464 		to->sb_gquotino = cpu_to_be64(from->sb_gquotino);
465 	else if (from->sb_qflags & XFS_PQUOTA_ACCT)
466 		to->sb_gquotino = cpu_to_be64(from->sb_pquotino);
467 	else {
468 		/*
469 		 * We can't rely on just the fields being logged to tell us
470 		 * that it is safe to write NULLFSINO - we should only do that
471 		 * if quotas are not actually enabled. Hence only write
472 		 * NULLFSINO if both in-core quota inodes are NULL.
473 		 */
474 		if (from->sb_gquotino == NULLFSINO &&
475 		    from->sb_pquotino == NULLFSINO)
476 			to->sb_gquotino = cpu_to_be64(NULLFSINO);
477 	}
478 
479 	to->sb_pquotino = 0;
480 }
481 
482 void
483 xfs_sb_to_disk(
484 	struct xfs_dsb	*to,
485 	struct xfs_sb	*from)
486 {
487 	xfs_sb_quota_to_disk(to, from);
488 
489 	to->sb_magicnum = cpu_to_be32(from->sb_magicnum);
490 	to->sb_blocksize = cpu_to_be32(from->sb_blocksize);
491 	to->sb_dblocks = cpu_to_be64(from->sb_dblocks);
492 	to->sb_rblocks = cpu_to_be64(from->sb_rblocks);
493 	to->sb_rextents = cpu_to_be64(from->sb_rextents);
494 	memcpy(&to->sb_uuid, &from->sb_uuid, sizeof(to->sb_uuid));
495 	to->sb_logstart = cpu_to_be64(from->sb_logstart);
496 	to->sb_rootino = cpu_to_be64(from->sb_rootino);
497 	to->sb_rbmino = cpu_to_be64(from->sb_rbmino);
498 	to->sb_rsumino = cpu_to_be64(from->sb_rsumino);
499 	to->sb_rextsize = cpu_to_be32(from->sb_rextsize);
500 	to->sb_agblocks = cpu_to_be32(from->sb_agblocks);
501 	to->sb_agcount = cpu_to_be32(from->sb_agcount);
502 	to->sb_rbmblocks = cpu_to_be32(from->sb_rbmblocks);
503 	to->sb_logblocks = cpu_to_be32(from->sb_logblocks);
504 	to->sb_versionnum = cpu_to_be16(from->sb_versionnum);
505 	to->sb_sectsize = cpu_to_be16(from->sb_sectsize);
506 	to->sb_inodesize = cpu_to_be16(from->sb_inodesize);
507 	to->sb_inopblock = cpu_to_be16(from->sb_inopblock);
508 	memcpy(&to->sb_fname, &from->sb_fname, sizeof(to->sb_fname));
509 	to->sb_blocklog = from->sb_blocklog;
510 	to->sb_sectlog = from->sb_sectlog;
511 	to->sb_inodelog = from->sb_inodelog;
512 	to->sb_inopblog = from->sb_inopblog;
513 	to->sb_agblklog = from->sb_agblklog;
514 	to->sb_rextslog = from->sb_rextslog;
515 	to->sb_inprogress = from->sb_inprogress;
516 	to->sb_imax_pct = from->sb_imax_pct;
517 	to->sb_icount = cpu_to_be64(from->sb_icount);
518 	to->sb_ifree = cpu_to_be64(from->sb_ifree);
519 	to->sb_fdblocks = cpu_to_be64(from->sb_fdblocks);
520 	to->sb_frextents = cpu_to_be64(from->sb_frextents);
521 
522 	to->sb_flags = from->sb_flags;
523 	to->sb_shared_vn = from->sb_shared_vn;
524 	to->sb_inoalignmt = cpu_to_be32(from->sb_inoalignmt);
525 	to->sb_unit = cpu_to_be32(from->sb_unit);
526 	to->sb_width = cpu_to_be32(from->sb_width);
527 	to->sb_dirblklog = from->sb_dirblklog;
528 	to->sb_logsectlog = from->sb_logsectlog;
529 	to->sb_logsectsize = cpu_to_be16(from->sb_logsectsize);
530 	to->sb_logsunit = cpu_to_be32(from->sb_logsunit);
531 
532 	/*
533 	 * We need to ensure that bad_features2 always matches features2.
534 	 * Hence we enforce that here rather than having to remember to do it
535 	 * everywhere else that updates features2.
536 	 */
537 	from->sb_bad_features2 = from->sb_features2;
538 	to->sb_features2 = cpu_to_be32(from->sb_features2);
539 	to->sb_bad_features2 = cpu_to_be32(from->sb_bad_features2);
540 
541 	if (xfs_sb_version_hascrc(from)) {
542 		to->sb_features_compat = cpu_to_be32(from->sb_features_compat);
543 		to->sb_features_ro_compat =
544 				cpu_to_be32(from->sb_features_ro_compat);
545 		to->sb_features_incompat =
546 				cpu_to_be32(from->sb_features_incompat);
547 		to->sb_features_log_incompat =
548 				cpu_to_be32(from->sb_features_log_incompat);
549 		to->sb_spino_align = cpu_to_be32(from->sb_spino_align);
550 		to->sb_lsn = cpu_to_be64(from->sb_lsn);
551 		if (xfs_sb_version_hasmetauuid(from))
552 			uuid_copy(&to->sb_meta_uuid, &from->sb_meta_uuid);
553 	}
554 }
555 
556 static int
557 xfs_sb_verify(
558 	struct xfs_buf	*bp,
559 	bool		check_version)
560 {
561 	struct xfs_mount *mp = bp->b_target->bt_mount;
562 	struct xfs_sb	sb;
563 
564 	/*
565 	 * Use call variant which doesn't convert quota flags from disk
566 	 * format, because xfs_mount_validate_sb checks the on-disk flags.
567 	 */
568 	__xfs_sb_from_disk(&sb, XFS_BUF_TO_SBP(bp), false);
569 
570 	/*
571 	 * Only check the in progress field for the primary superblock as
572 	 * mkfs.xfs doesn't clear it from secondary superblocks.
573 	 */
574 	return xfs_mount_validate_sb(mp, &sb, bp->b_bn == XFS_SB_DADDR,
575 				     check_version);
576 }
577 
578 /*
579  * If the superblock has the CRC feature bit set or the CRC field is non-null,
580  * check that the CRC is valid.  We check the CRC field is non-null because a
581  * single bit error could clear the feature bit and unused parts of the
582  * superblock are supposed to be zero. Hence a non-null crc field indicates that
583  * we've potentially lost a feature bit and we should check it anyway.
584  *
585  * However, past bugs (i.e. in growfs) left non-zeroed regions beyond the
586  * last field in V4 secondary superblocks.  So for secondary superblocks,
587  * we are more forgiving, and ignore CRC failures if the primary doesn't
588  * indicate that the fs version is V5.
589  */
590 static void
591 xfs_sb_read_verify(
592 	struct xfs_buf	*bp)
593 {
594 	struct xfs_mount *mp = bp->b_target->bt_mount;
595 	struct xfs_dsb	*dsb = XFS_BUF_TO_SBP(bp);
596 	int		error;
597 
598 	/*
599 	 * open code the version check to avoid needing to convert the entire
600 	 * superblock from disk order just to check the version number
601 	 */
602 	if (dsb->sb_magicnum == cpu_to_be32(XFS_SB_MAGIC) &&
603 	    (((be16_to_cpu(dsb->sb_versionnum) & XFS_SB_VERSION_NUMBITS) ==
604 						XFS_SB_VERSION_5) ||
605 	     dsb->sb_crc != 0)) {
606 
607 		if (!xfs_buf_verify_cksum(bp, XFS_SB_CRC_OFF)) {
608 			/* Only fail bad secondaries on a known V5 filesystem */
609 			if (bp->b_bn == XFS_SB_DADDR ||
610 			    xfs_sb_version_hascrc(&mp->m_sb)) {
611 				error = -EFSBADCRC;
612 				goto out_error;
613 			}
614 		}
615 	}
616 	error = xfs_sb_verify(bp, true);
617 
618 out_error:
619 	if (error) {
620 		xfs_buf_ioerror(bp, error);
621 		if (error == -EFSCORRUPTED || error == -EFSBADCRC)
622 			xfs_verifier_error(bp);
623 	}
624 }
625 
626 /*
627  * We may be probed for a filesystem match, so we may not want to emit
628  * messages when the superblock buffer is not actually an XFS superblock.
629  * If we find an XFS superblock, then run a normal, noisy mount because we are
630  * really going to mount it and want to know about errors.
631  */
632 static void
633 xfs_sb_quiet_read_verify(
634 	struct xfs_buf	*bp)
635 {
636 	struct xfs_dsb	*dsb = XFS_BUF_TO_SBP(bp);
637 
638 	if (dsb->sb_magicnum == cpu_to_be32(XFS_SB_MAGIC)) {
639 		/* XFS filesystem, verify noisily! */
640 		xfs_sb_read_verify(bp);
641 		return;
642 	}
643 	/* quietly fail */
644 	xfs_buf_ioerror(bp, -EWRONGFS);
645 }
646 
647 static void
648 xfs_sb_write_verify(
649 	struct xfs_buf		*bp)
650 {
651 	struct xfs_mount	*mp = bp->b_target->bt_mount;
652 	struct xfs_buf_log_item	*bip = bp->b_fspriv;
653 	int			error;
654 
655 	error = xfs_sb_verify(bp, false);
656 	if (error) {
657 		xfs_buf_ioerror(bp, error);
658 		xfs_verifier_error(bp);
659 		return;
660 	}
661 
662 	if (!xfs_sb_version_hascrc(&mp->m_sb))
663 		return;
664 
665 	if (bip)
666 		XFS_BUF_TO_SBP(bp)->sb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
667 
668 	xfs_buf_update_cksum(bp, XFS_SB_CRC_OFF);
669 }
670 
671 const struct xfs_buf_ops xfs_sb_buf_ops = {
672 	.verify_read = xfs_sb_read_verify,
673 	.verify_write = xfs_sb_write_verify,
674 };
675 
676 const struct xfs_buf_ops xfs_sb_quiet_buf_ops = {
677 	.verify_read = xfs_sb_quiet_read_verify,
678 	.verify_write = xfs_sb_write_verify,
679 };
680 
681 /*
682  * xfs_mount_common
683  *
684  * Mount initialization code establishing various mount
685  * fields from the superblock associated with the given
686  * mount structure
687  */
688 void
689 xfs_sb_mount_common(
690 	struct xfs_mount *mp,
691 	struct xfs_sb	*sbp)
692 {
693 	mp->m_agfrotor = mp->m_agirotor = 0;
694 	spin_lock_init(&mp->m_agirotor_lock);
695 	mp->m_maxagi = mp->m_sb.sb_agcount;
696 	mp->m_blkbit_log = sbp->sb_blocklog + XFS_NBBYLOG;
697 	mp->m_blkbb_log = sbp->sb_blocklog - BBSHIFT;
698 	mp->m_sectbb_log = sbp->sb_sectlog - BBSHIFT;
699 	mp->m_agno_log = xfs_highbit32(sbp->sb_agcount - 1) + 1;
700 	mp->m_agino_log = sbp->sb_inopblog + sbp->sb_agblklog;
701 	mp->m_blockmask = sbp->sb_blocksize - 1;
702 	mp->m_blockwsize = sbp->sb_blocksize >> XFS_WORDLOG;
703 	mp->m_blockwmask = mp->m_blockwsize - 1;
704 
705 	mp->m_alloc_mxr[0] = xfs_allocbt_maxrecs(mp, sbp->sb_blocksize, 1);
706 	mp->m_alloc_mxr[1] = xfs_allocbt_maxrecs(mp, sbp->sb_blocksize, 0);
707 	mp->m_alloc_mnr[0] = mp->m_alloc_mxr[0] / 2;
708 	mp->m_alloc_mnr[1] = mp->m_alloc_mxr[1] / 2;
709 
710 	mp->m_inobt_mxr[0] = xfs_inobt_maxrecs(mp, sbp->sb_blocksize, 1);
711 	mp->m_inobt_mxr[1] = xfs_inobt_maxrecs(mp, sbp->sb_blocksize, 0);
712 	mp->m_inobt_mnr[0] = mp->m_inobt_mxr[0] / 2;
713 	mp->m_inobt_mnr[1] = mp->m_inobt_mxr[1] / 2;
714 
715 	mp->m_bmap_dmxr[0] = xfs_bmbt_maxrecs(mp, sbp->sb_blocksize, 1);
716 	mp->m_bmap_dmxr[1] = xfs_bmbt_maxrecs(mp, sbp->sb_blocksize, 0);
717 	mp->m_bmap_dmnr[0] = mp->m_bmap_dmxr[0] / 2;
718 	mp->m_bmap_dmnr[1] = mp->m_bmap_dmxr[1] / 2;
719 
720 	mp->m_bsize = XFS_FSB_TO_BB(mp, 1);
721 	mp->m_ialloc_inos = (int)MAX((__uint16_t)XFS_INODES_PER_CHUNK,
722 					sbp->sb_inopblock);
723 	mp->m_ialloc_blks = mp->m_ialloc_inos >> sbp->sb_inopblog;
724 
725 	if (sbp->sb_spino_align)
726 		mp->m_ialloc_min_blks = sbp->sb_spino_align;
727 	else
728 		mp->m_ialloc_min_blks = mp->m_ialloc_blks;
729 }
730 
731 /*
732  * xfs_initialize_perag_data
733  *
734  * Read in each per-ag structure so we can count up the number of
735  * allocated inodes, free inodes and used filesystem blocks as this
736  * information is no longer persistent in the superblock. Once we have
737  * this information, write it into the in-core superblock structure.
738  */
739 int
740 xfs_initialize_perag_data(
741 	struct xfs_mount *mp,
742 	xfs_agnumber_t	agcount)
743 {
744 	xfs_agnumber_t	index;
745 	xfs_perag_t	*pag;
746 	xfs_sb_t	*sbp = &mp->m_sb;
747 	uint64_t	ifree = 0;
748 	uint64_t	ialloc = 0;
749 	uint64_t	bfree = 0;
750 	uint64_t	bfreelst = 0;
751 	uint64_t	btree = 0;
752 	int		error;
753 
754 	for (index = 0; index < agcount; index++) {
755 		/*
756 		 * read the agf, then the agi. This gets us
757 		 * all the information we need and populates the
758 		 * per-ag structures for us.
759 		 */
760 		error = xfs_alloc_pagf_init(mp, NULL, index, 0);
761 		if (error)
762 			return error;
763 
764 		error = xfs_ialloc_pagi_init(mp, NULL, index);
765 		if (error)
766 			return error;
767 		pag = xfs_perag_get(mp, index);
768 		ifree += pag->pagi_freecount;
769 		ialloc += pag->pagi_count;
770 		bfree += pag->pagf_freeblks;
771 		bfreelst += pag->pagf_flcount;
772 		btree += pag->pagf_btreeblks;
773 		xfs_perag_put(pag);
774 	}
775 
776 	/* Overwrite incore superblock counters with just-read data */
777 	spin_lock(&mp->m_sb_lock);
778 	sbp->sb_ifree = ifree;
779 	sbp->sb_icount = ialloc;
780 	sbp->sb_fdblocks = bfree + bfreelst + btree;
781 	spin_unlock(&mp->m_sb_lock);
782 
783 	xfs_reinit_percpu_counters(mp);
784 
785 	return 0;
786 }
787 
788 /*
789  * xfs_log_sb() can be used to copy arbitrary changes to the in-core superblock
790  * into the superblock buffer to be logged.  It does not provide the higher
791  * level of locking that is needed to protect the in-core superblock from
792  * concurrent access.
793  */
794 void
795 xfs_log_sb(
796 	struct xfs_trans	*tp)
797 {
798 	struct xfs_mount	*mp = tp->t_mountp;
799 	struct xfs_buf		*bp = xfs_trans_getsb(tp, mp, 0);
800 
801 	mp->m_sb.sb_icount = percpu_counter_sum(&mp->m_icount);
802 	mp->m_sb.sb_ifree = percpu_counter_sum(&mp->m_ifree);
803 	mp->m_sb.sb_fdblocks = percpu_counter_sum(&mp->m_fdblocks);
804 
805 	xfs_sb_to_disk(XFS_BUF_TO_SBP(bp), &mp->m_sb);
806 	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SB_BUF);
807 	xfs_trans_log_buf(tp, bp, 0, sizeof(struct xfs_dsb));
808 }
809 
810 /*
811  * xfs_sync_sb
812  *
813  * Sync the superblock to disk.
814  *
815  * Note that the caller is responsible for checking the frozen state of the
816  * filesystem. This procedure uses the non-blocking transaction allocator and
817  * thus will allow modifications to a frozen fs. This is required because this
818  * code can be called during the process of freezing where use of the high-level
819  * allocator would deadlock.
820  */
821 int
822 xfs_sync_sb(
823 	struct xfs_mount	*mp,
824 	bool			wait)
825 {
826 	struct xfs_trans	*tp;
827 	int			error;
828 
829 	tp = _xfs_trans_alloc(mp, XFS_TRANS_SB_CHANGE, KM_SLEEP);
830 	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_sb, 0, 0);
831 	if (error) {
832 		xfs_trans_cancel(tp);
833 		return error;
834 	}
835 
836 	xfs_log_sb(tp);
837 	if (wait)
838 		xfs_trans_set_sync(tp);
839 	return xfs_trans_commit(tp);
840 }
841