xref: /openbmc/linux/fs/xfs/xfs_mount.c (revision e2f1cf25)
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_da_format.h"
28 #include "xfs_da_btree.h"
29 #include "xfs_inode.h"
30 #include "xfs_dir2.h"
31 #include "xfs_ialloc.h"
32 #include "xfs_alloc.h"
33 #include "xfs_rtalloc.h"
34 #include "xfs_bmap.h"
35 #include "xfs_trans.h"
36 #include "xfs_trans_priv.h"
37 #include "xfs_log.h"
38 #include "xfs_error.h"
39 #include "xfs_quota.h"
40 #include "xfs_fsops.h"
41 #include "xfs_trace.h"
42 #include "xfs_icache.h"
43 #include "xfs_sysfs.h"
44 
45 
46 static DEFINE_MUTEX(xfs_uuid_table_mutex);
47 static int xfs_uuid_table_size;
48 static uuid_t *xfs_uuid_table;
49 
50 /*
51  * See if the UUID is unique among mounted XFS filesystems.
52  * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
53  */
54 STATIC int
55 xfs_uuid_mount(
56 	struct xfs_mount	*mp)
57 {
58 	uuid_t			*uuid = &mp->m_sb.sb_uuid;
59 	int			hole, i;
60 
61 	if (mp->m_flags & XFS_MOUNT_NOUUID)
62 		return 0;
63 
64 	if (uuid_is_nil(uuid)) {
65 		xfs_warn(mp, "Filesystem has nil UUID - can't mount");
66 		return -EINVAL;
67 	}
68 
69 	mutex_lock(&xfs_uuid_table_mutex);
70 	for (i = 0, hole = -1; i < xfs_uuid_table_size; i++) {
71 		if (uuid_is_nil(&xfs_uuid_table[i])) {
72 			hole = i;
73 			continue;
74 		}
75 		if (uuid_equal(uuid, &xfs_uuid_table[i]))
76 			goto out_duplicate;
77 	}
78 
79 	if (hole < 0) {
80 		xfs_uuid_table = kmem_realloc(xfs_uuid_table,
81 			(xfs_uuid_table_size + 1) * sizeof(*xfs_uuid_table),
82 			xfs_uuid_table_size  * sizeof(*xfs_uuid_table),
83 			KM_SLEEP);
84 		hole = xfs_uuid_table_size++;
85 	}
86 	xfs_uuid_table[hole] = *uuid;
87 	mutex_unlock(&xfs_uuid_table_mutex);
88 
89 	return 0;
90 
91  out_duplicate:
92 	mutex_unlock(&xfs_uuid_table_mutex);
93 	xfs_warn(mp, "Filesystem has duplicate UUID %pU - can't mount", uuid);
94 	return -EINVAL;
95 }
96 
97 STATIC void
98 xfs_uuid_unmount(
99 	struct xfs_mount	*mp)
100 {
101 	uuid_t			*uuid = &mp->m_sb.sb_uuid;
102 	int			i;
103 
104 	if (mp->m_flags & XFS_MOUNT_NOUUID)
105 		return;
106 
107 	mutex_lock(&xfs_uuid_table_mutex);
108 	for (i = 0; i < xfs_uuid_table_size; i++) {
109 		if (uuid_is_nil(&xfs_uuid_table[i]))
110 			continue;
111 		if (!uuid_equal(uuid, &xfs_uuid_table[i]))
112 			continue;
113 		memset(&xfs_uuid_table[i], 0, sizeof(uuid_t));
114 		break;
115 	}
116 	ASSERT(i < xfs_uuid_table_size);
117 	mutex_unlock(&xfs_uuid_table_mutex);
118 }
119 
120 
121 STATIC void
122 __xfs_free_perag(
123 	struct rcu_head	*head)
124 {
125 	struct xfs_perag *pag = container_of(head, struct xfs_perag, rcu_head);
126 
127 	ASSERT(atomic_read(&pag->pag_ref) == 0);
128 	kmem_free(pag);
129 }
130 
131 /*
132  * Free up the per-ag resources associated with the mount structure.
133  */
134 STATIC void
135 xfs_free_perag(
136 	xfs_mount_t	*mp)
137 {
138 	xfs_agnumber_t	agno;
139 	struct xfs_perag *pag;
140 
141 	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
142 		spin_lock(&mp->m_perag_lock);
143 		pag = radix_tree_delete(&mp->m_perag_tree, agno);
144 		spin_unlock(&mp->m_perag_lock);
145 		ASSERT(pag);
146 		ASSERT(atomic_read(&pag->pag_ref) == 0);
147 		call_rcu(&pag->rcu_head, __xfs_free_perag);
148 	}
149 }
150 
151 /*
152  * Check size of device based on the (data/realtime) block count.
153  * Note: this check is used by the growfs code as well as mount.
154  */
155 int
156 xfs_sb_validate_fsb_count(
157 	xfs_sb_t	*sbp,
158 	__uint64_t	nblocks)
159 {
160 	ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
161 	ASSERT(sbp->sb_blocklog >= BBSHIFT);
162 
163 	/* Limited by ULONG_MAX of page cache index */
164 	if (nblocks >> (PAGE_CACHE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
165 		return -EFBIG;
166 	return 0;
167 }
168 
169 int
170 xfs_initialize_perag(
171 	xfs_mount_t	*mp,
172 	xfs_agnumber_t	agcount,
173 	xfs_agnumber_t	*maxagi)
174 {
175 	xfs_agnumber_t	index;
176 	xfs_agnumber_t	first_initialised = 0;
177 	xfs_perag_t	*pag;
178 	xfs_agino_t	agino;
179 	xfs_ino_t	ino;
180 	xfs_sb_t	*sbp = &mp->m_sb;
181 	int		error = -ENOMEM;
182 
183 	/*
184 	 * Walk the current per-ag tree so we don't try to initialise AGs
185 	 * that already exist (growfs case). Allocate and insert all the
186 	 * AGs we don't find ready for initialisation.
187 	 */
188 	for (index = 0; index < agcount; index++) {
189 		pag = xfs_perag_get(mp, index);
190 		if (pag) {
191 			xfs_perag_put(pag);
192 			continue;
193 		}
194 		if (!first_initialised)
195 			first_initialised = index;
196 
197 		pag = kmem_zalloc(sizeof(*pag), KM_MAYFAIL);
198 		if (!pag)
199 			goto out_unwind;
200 		pag->pag_agno = index;
201 		pag->pag_mount = mp;
202 		spin_lock_init(&pag->pag_ici_lock);
203 		mutex_init(&pag->pag_ici_reclaim_lock);
204 		INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
205 		spin_lock_init(&pag->pag_buf_lock);
206 		pag->pag_buf_tree = RB_ROOT;
207 
208 		if (radix_tree_preload(GFP_NOFS))
209 			goto out_unwind;
210 
211 		spin_lock(&mp->m_perag_lock);
212 		if (radix_tree_insert(&mp->m_perag_tree, index, pag)) {
213 			BUG();
214 			spin_unlock(&mp->m_perag_lock);
215 			radix_tree_preload_end();
216 			error = -EEXIST;
217 			goto out_unwind;
218 		}
219 		spin_unlock(&mp->m_perag_lock);
220 		radix_tree_preload_end();
221 	}
222 
223 	/*
224 	 * If we mount with the inode64 option, or no inode overflows
225 	 * the legacy 32-bit address space clear the inode32 option.
226 	 */
227 	agino = XFS_OFFBNO_TO_AGINO(mp, sbp->sb_agblocks - 1, 0);
228 	ino = XFS_AGINO_TO_INO(mp, agcount - 1, agino);
229 
230 	if ((mp->m_flags & XFS_MOUNT_SMALL_INUMS) && ino > XFS_MAXINUMBER_32)
231 		mp->m_flags |= XFS_MOUNT_32BITINODES;
232 	else
233 		mp->m_flags &= ~XFS_MOUNT_32BITINODES;
234 
235 	if (mp->m_flags & XFS_MOUNT_32BITINODES)
236 		index = xfs_set_inode32(mp, agcount);
237 	else
238 		index = xfs_set_inode64(mp, agcount);
239 
240 	if (maxagi)
241 		*maxagi = index;
242 	return 0;
243 
244 out_unwind:
245 	kmem_free(pag);
246 	for (; index > first_initialised; index--) {
247 		pag = radix_tree_delete(&mp->m_perag_tree, index);
248 		kmem_free(pag);
249 	}
250 	return error;
251 }
252 
253 /*
254  * xfs_readsb
255  *
256  * Does the initial read of the superblock.
257  */
258 int
259 xfs_readsb(
260 	struct xfs_mount *mp,
261 	int		flags)
262 {
263 	unsigned int	sector_size;
264 	struct xfs_buf	*bp;
265 	struct xfs_sb	*sbp = &mp->m_sb;
266 	int		error;
267 	int		loud = !(flags & XFS_MFSI_QUIET);
268 	const struct xfs_buf_ops *buf_ops;
269 
270 	ASSERT(mp->m_sb_bp == NULL);
271 	ASSERT(mp->m_ddev_targp != NULL);
272 
273 	/*
274 	 * For the initial read, we must guess at the sector
275 	 * size based on the block device.  It's enough to
276 	 * get the sb_sectsize out of the superblock and
277 	 * then reread with the proper length.
278 	 * We don't verify it yet, because it may not be complete.
279 	 */
280 	sector_size = xfs_getsize_buftarg(mp->m_ddev_targp);
281 	buf_ops = NULL;
282 
283 	/*
284 	 * Allocate a (locked) buffer to hold the superblock.
285 	 * This will be kept around at all times to optimize
286 	 * access to the superblock.
287 	 */
288 reread:
289 	error = xfs_buf_read_uncached(mp->m_ddev_targp, XFS_SB_DADDR,
290 				   BTOBB(sector_size), 0, &bp, buf_ops);
291 	if (error) {
292 		if (loud)
293 			xfs_warn(mp, "SB validate failed with error %d.", error);
294 		/* bad CRC means corrupted metadata */
295 		if (error == -EFSBADCRC)
296 			error = -EFSCORRUPTED;
297 		return error;
298 	}
299 
300 	/*
301 	 * Initialize the mount structure from the superblock.
302 	 */
303 	xfs_sb_from_disk(sbp, XFS_BUF_TO_SBP(bp));
304 
305 	/*
306 	 * If we haven't validated the superblock, do so now before we try
307 	 * to check the sector size and reread the superblock appropriately.
308 	 */
309 	if (sbp->sb_magicnum != XFS_SB_MAGIC) {
310 		if (loud)
311 			xfs_warn(mp, "Invalid superblock magic number");
312 		error = -EINVAL;
313 		goto release_buf;
314 	}
315 
316 	/*
317 	 * We must be able to do sector-sized and sector-aligned IO.
318 	 */
319 	if (sector_size > sbp->sb_sectsize) {
320 		if (loud)
321 			xfs_warn(mp, "device supports %u byte sectors (not %u)",
322 				sector_size, sbp->sb_sectsize);
323 		error = -ENOSYS;
324 		goto release_buf;
325 	}
326 
327 	if (buf_ops == NULL) {
328 		/*
329 		 * Re-read the superblock so the buffer is correctly sized,
330 		 * and properly verified.
331 		 */
332 		xfs_buf_relse(bp);
333 		sector_size = sbp->sb_sectsize;
334 		buf_ops = loud ? &xfs_sb_buf_ops : &xfs_sb_quiet_buf_ops;
335 		goto reread;
336 	}
337 
338 	xfs_reinit_percpu_counters(mp);
339 
340 	/* no need to be quiet anymore, so reset the buf ops */
341 	bp->b_ops = &xfs_sb_buf_ops;
342 
343 	mp->m_sb_bp = bp;
344 	xfs_buf_unlock(bp);
345 	return 0;
346 
347 release_buf:
348 	xfs_buf_relse(bp);
349 	return error;
350 }
351 
352 /*
353  * Update alignment values based on mount options and sb values
354  */
355 STATIC int
356 xfs_update_alignment(xfs_mount_t *mp)
357 {
358 	xfs_sb_t	*sbp = &(mp->m_sb);
359 
360 	if (mp->m_dalign) {
361 		/*
362 		 * If stripe unit and stripe width are not multiples
363 		 * of the fs blocksize turn off alignment.
364 		 */
365 		if ((BBTOB(mp->m_dalign) & mp->m_blockmask) ||
366 		    (BBTOB(mp->m_swidth) & mp->m_blockmask)) {
367 			xfs_warn(mp,
368 		"alignment check failed: sunit/swidth vs. blocksize(%d)",
369 				sbp->sb_blocksize);
370 			return -EINVAL;
371 		} else {
372 			/*
373 			 * Convert the stripe unit and width to FSBs.
374 			 */
375 			mp->m_dalign = XFS_BB_TO_FSBT(mp, mp->m_dalign);
376 			if (mp->m_dalign && (sbp->sb_agblocks % mp->m_dalign)) {
377 				xfs_warn(mp,
378 			"alignment check failed: sunit/swidth vs. agsize(%d)",
379 					 sbp->sb_agblocks);
380 				return -EINVAL;
381 			} else if (mp->m_dalign) {
382 				mp->m_swidth = XFS_BB_TO_FSBT(mp, mp->m_swidth);
383 			} else {
384 				xfs_warn(mp,
385 			"alignment check failed: sunit(%d) less than bsize(%d)",
386 					 mp->m_dalign, sbp->sb_blocksize);
387 				return -EINVAL;
388 			}
389 		}
390 
391 		/*
392 		 * Update superblock with new values
393 		 * and log changes
394 		 */
395 		if (xfs_sb_version_hasdalign(sbp)) {
396 			if (sbp->sb_unit != mp->m_dalign) {
397 				sbp->sb_unit = mp->m_dalign;
398 				mp->m_update_sb = true;
399 			}
400 			if (sbp->sb_width != mp->m_swidth) {
401 				sbp->sb_width = mp->m_swidth;
402 				mp->m_update_sb = true;
403 			}
404 		} else {
405 			xfs_warn(mp,
406 	"cannot change alignment: superblock does not support data alignment");
407 			return -EINVAL;
408 		}
409 	} else if ((mp->m_flags & XFS_MOUNT_NOALIGN) != XFS_MOUNT_NOALIGN &&
410 		    xfs_sb_version_hasdalign(&mp->m_sb)) {
411 			mp->m_dalign = sbp->sb_unit;
412 			mp->m_swidth = sbp->sb_width;
413 	}
414 
415 	return 0;
416 }
417 
418 /*
419  * Set the maximum inode count for this filesystem
420  */
421 STATIC void
422 xfs_set_maxicount(xfs_mount_t *mp)
423 {
424 	xfs_sb_t	*sbp = &(mp->m_sb);
425 	__uint64_t	icount;
426 
427 	if (sbp->sb_imax_pct) {
428 		/*
429 		 * Make sure the maximum inode count is a multiple
430 		 * of the units we allocate inodes in.
431 		 */
432 		icount = sbp->sb_dblocks * sbp->sb_imax_pct;
433 		do_div(icount, 100);
434 		do_div(icount, mp->m_ialloc_blks);
435 		mp->m_maxicount = (icount * mp->m_ialloc_blks)  <<
436 				   sbp->sb_inopblog;
437 	} else {
438 		mp->m_maxicount = 0;
439 	}
440 }
441 
442 /*
443  * Set the default minimum read and write sizes unless
444  * already specified in a mount option.
445  * We use smaller I/O sizes when the file system
446  * is being used for NFS service (wsync mount option).
447  */
448 STATIC void
449 xfs_set_rw_sizes(xfs_mount_t *mp)
450 {
451 	xfs_sb_t	*sbp = &(mp->m_sb);
452 	int		readio_log, writeio_log;
453 
454 	if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
455 		if (mp->m_flags & XFS_MOUNT_WSYNC) {
456 			readio_log = XFS_WSYNC_READIO_LOG;
457 			writeio_log = XFS_WSYNC_WRITEIO_LOG;
458 		} else {
459 			readio_log = XFS_READIO_LOG_LARGE;
460 			writeio_log = XFS_WRITEIO_LOG_LARGE;
461 		}
462 	} else {
463 		readio_log = mp->m_readio_log;
464 		writeio_log = mp->m_writeio_log;
465 	}
466 
467 	if (sbp->sb_blocklog > readio_log) {
468 		mp->m_readio_log = sbp->sb_blocklog;
469 	} else {
470 		mp->m_readio_log = readio_log;
471 	}
472 	mp->m_readio_blocks = 1 << (mp->m_readio_log - sbp->sb_blocklog);
473 	if (sbp->sb_blocklog > writeio_log) {
474 		mp->m_writeio_log = sbp->sb_blocklog;
475 	} else {
476 		mp->m_writeio_log = writeio_log;
477 	}
478 	mp->m_writeio_blocks = 1 << (mp->m_writeio_log - sbp->sb_blocklog);
479 }
480 
481 /*
482  * precalculate the low space thresholds for dynamic speculative preallocation.
483  */
484 void
485 xfs_set_low_space_thresholds(
486 	struct xfs_mount	*mp)
487 {
488 	int i;
489 
490 	for (i = 0; i < XFS_LOWSP_MAX; i++) {
491 		__uint64_t space = mp->m_sb.sb_dblocks;
492 
493 		do_div(space, 100);
494 		mp->m_low_space[i] = space * (i + 1);
495 	}
496 }
497 
498 
499 /*
500  * Set whether we're using inode alignment.
501  */
502 STATIC void
503 xfs_set_inoalignment(xfs_mount_t *mp)
504 {
505 	if (xfs_sb_version_hasalign(&mp->m_sb) &&
506 	    mp->m_sb.sb_inoalignmt >=
507 	    XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size))
508 		mp->m_inoalign_mask = mp->m_sb.sb_inoalignmt - 1;
509 	else
510 		mp->m_inoalign_mask = 0;
511 	/*
512 	 * If we are using stripe alignment, check whether
513 	 * the stripe unit is a multiple of the inode alignment
514 	 */
515 	if (mp->m_dalign && mp->m_inoalign_mask &&
516 	    !(mp->m_dalign & mp->m_inoalign_mask))
517 		mp->m_sinoalign = mp->m_dalign;
518 	else
519 		mp->m_sinoalign = 0;
520 }
521 
522 /*
523  * Check that the data (and log if separate) is an ok size.
524  */
525 STATIC int
526 xfs_check_sizes(
527 	struct xfs_mount *mp)
528 {
529 	struct xfs_buf	*bp;
530 	xfs_daddr_t	d;
531 	int		error;
532 
533 	d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
534 	if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
535 		xfs_warn(mp, "filesystem size mismatch detected");
536 		return -EFBIG;
537 	}
538 	error = xfs_buf_read_uncached(mp->m_ddev_targp,
539 					d - XFS_FSS_TO_BB(mp, 1),
540 					XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);
541 	if (error) {
542 		xfs_warn(mp, "last sector read failed");
543 		return error;
544 	}
545 	xfs_buf_relse(bp);
546 
547 	if (mp->m_logdev_targp == mp->m_ddev_targp)
548 		return 0;
549 
550 	d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
551 	if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
552 		xfs_warn(mp, "log size mismatch detected");
553 		return -EFBIG;
554 	}
555 	error = xfs_buf_read_uncached(mp->m_logdev_targp,
556 					d - XFS_FSB_TO_BB(mp, 1),
557 					XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
558 	if (error) {
559 		xfs_warn(mp, "log device read failed");
560 		return error;
561 	}
562 	xfs_buf_relse(bp);
563 	return 0;
564 }
565 
566 /*
567  * Clear the quotaflags in memory and in the superblock.
568  */
569 int
570 xfs_mount_reset_sbqflags(
571 	struct xfs_mount	*mp)
572 {
573 	mp->m_qflags = 0;
574 
575 	/* It is OK to look at sb_qflags in the mount path without m_sb_lock. */
576 	if (mp->m_sb.sb_qflags == 0)
577 		return 0;
578 	spin_lock(&mp->m_sb_lock);
579 	mp->m_sb.sb_qflags = 0;
580 	spin_unlock(&mp->m_sb_lock);
581 
582 	if (!xfs_fs_writable(mp, SB_FREEZE_WRITE))
583 		return 0;
584 
585 	return xfs_sync_sb(mp, false);
586 }
587 
588 __uint64_t
589 xfs_default_resblks(xfs_mount_t *mp)
590 {
591 	__uint64_t resblks;
592 
593 	/*
594 	 * We default to 5% or 8192 fsbs of space reserved, whichever is
595 	 * smaller.  This is intended to cover concurrent allocation
596 	 * transactions when we initially hit enospc. These each require a 4
597 	 * block reservation. Hence by default we cover roughly 2000 concurrent
598 	 * allocation reservations.
599 	 */
600 	resblks = mp->m_sb.sb_dblocks;
601 	do_div(resblks, 20);
602 	resblks = min_t(__uint64_t, resblks, 8192);
603 	return resblks;
604 }
605 
606 /*
607  * This function does the following on an initial mount of a file system:
608  *	- reads the superblock from disk and init the mount struct
609  *	- if we're a 32-bit kernel, do a size check on the superblock
610  *		so we don't mount terabyte filesystems
611  *	- init mount struct realtime fields
612  *	- allocate inode hash table for fs
613  *	- init directory manager
614  *	- perform recovery and init the log manager
615  */
616 int
617 xfs_mountfs(
618 	xfs_mount_t	*mp)
619 {
620 	xfs_sb_t	*sbp = &(mp->m_sb);
621 	xfs_inode_t	*rip;
622 	__uint64_t	resblks;
623 	uint		quotamount = 0;
624 	uint		quotaflags = 0;
625 	int		error = 0;
626 
627 	xfs_sb_mount_common(mp, sbp);
628 
629 	/*
630 	 * Check for a mismatched features2 values.  Older kernels read & wrote
631 	 * into the wrong sb offset for sb_features2 on some platforms due to
632 	 * xfs_sb_t not being 64bit size aligned when sb_features2 was added,
633 	 * which made older superblock reading/writing routines swap it as a
634 	 * 64-bit value.
635 	 *
636 	 * For backwards compatibility, we make both slots equal.
637 	 *
638 	 * If we detect a mismatched field, we OR the set bits into the existing
639 	 * features2 field in case it has already been modified; we don't want
640 	 * to lose any features.  We then update the bad location with the ORed
641 	 * value so that older kernels will see any features2 flags. The
642 	 * superblock writeback code ensures the new sb_features2 is copied to
643 	 * sb_bad_features2 before it is logged or written to disk.
644 	 */
645 	if (xfs_sb_has_mismatched_features2(sbp)) {
646 		xfs_warn(mp, "correcting sb_features alignment problem");
647 		sbp->sb_features2 |= sbp->sb_bad_features2;
648 		mp->m_update_sb = true;
649 
650 		/*
651 		 * Re-check for ATTR2 in case it was found in bad_features2
652 		 * slot.
653 		 */
654 		if (xfs_sb_version_hasattr2(&mp->m_sb) &&
655 		   !(mp->m_flags & XFS_MOUNT_NOATTR2))
656 			mp->m_flags |= XFS_MOUNT_ATTR2;
657 	}
658 
659 	if (xfs_sb_version_hasattr2(&mp->m_sb) &&
660 	   (mp->m_flags & XFS_MOUNT_NOATTR2)) {
661 		xfs_sb_version_removeattr2(&mp->m_sb);
662 		mp->m_update_sb = true;
663 
664 		/* update sb_versionnum for the clearing of the morebits */
665 		if (!sbp->sb_features2)
666 			mp->m_update_sb = true;
667 	}
668 
669 	/* always use v2 inodes by default now */
670 	if (!(mp->m_sb.sb_versionnum & XFS_SB_VERSION_NLINKBIT)) {
671 		mp->m_sb.sb_versionnum |= XFS_SB_VERSION_NLINKBIT;
672 		mp->m_update_sb = true;
673 	}
674 
675 	/*
676 	 * Check if sb_agblocks is aligned at stripe boundary
677 	 * If sb_agblocks is NOT aligned turn off m_dalign since
678 	 * allocator alignment is within an ag, therefore ag has
679 	 * to be aligned at stripe boundary.
680 	 */
681 	error = xfs_update_alignment(mp);
682 	if (error)
683 		goto out;
684 
685 	xfs_alloc_compute_maxlevels(mp);
686 	xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK);
687 	xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK);
688 	xfs_ialloc_compute_maxlevels(mp);
689 
690 	xfs_set_maxicount(mp);
691 
692 	error = xfs_sysfs_init(&mp->m_kobj, &xfs_mp_ktype, NULL, mp->m_fsname);
693 	if (error)
694 		goto out;
695 
696 	error = xfs_uuid_mount(mp);
697 	if (error)
698 		goto out_remove_sysfs;
699 
700 	/*
701 	 * Set the minimum read and write sizes
702 	 */
703 	xfs_set_rw_sizes(mp);
704 
705 	/* set the low space thresholds for dynamic preallocation */
706 	xfs_set_low_space_thresholds(mp);
707 
708 	/*
709 	 * Set the inode cluster size.
710 	 * This may still be overridden by the file system
711 	 * block size if it is larger than the chosen cluster size.
712 	 *
713 	 * For v5 filesystems, scale the cluster size with the inode size to
714 	 * keep a constant ratio of inode per cluster buffer, but only if mkfs
715 	 * has set the inode alignment value appropriately for larger cluster
716 	 * sizes.
717 	 */
718 	mp->m_inode_cluster_size = XFS_INODE_BIG_CLUSTER_SIZE;
719 	if (xfs_sb_version_hascrc(&mp->m_sb)) {
720 		int	new_size = mp->m_inode_cluster_size;
721 
722 		new_size *= mp->m_sb.sb_inodesize / XFS_DINODE_MIN_SIZE;
723 		if (mp->m_sb.sb_inoalignmt >= XFS_B_TO_FSBT(mp, new_size))
724 			mp->m_inode_cluster_size = new_size;
725 	}
726 
727 	/*
728 	 * If enabled, sparse inode chunk alignment is expected to match the
729 	 * cluster size. Full inode chunk alignment must match the chunk size,
730 	 * but that is checked on sb read verification...
731 	 */
732 	if (xfs_sb_version_hassparseinodes(&mp->m_sb) &&
733 	    mp->m_sb.sb_spino_align !=
734 			XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size)) {
735 		xfs_warn(mp,
736 	"Sparse inode block alignment (%u) must match cluster size (%llu).",
737 			 mp->m_sb.sb_spino_align,
738 			 XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size));
739 		error = -EINVAL;
740 		goto out_remove_uuid;
741 	}
742 
743 	/*
744 	 * Set inode alignment fields
745 	 */
746 	xfs_set_inoalignment(mp);
747 
748 	/*
749 	 * Check that the data (and log if separate) is an ok size.
750 	 */
751 	error = xfs_check_sizes(mp);
752 	if (error)
753 		goto out_remove_uuid;
754 
755 	/*
756 	 * Initialize realtime fields in the mount structure
757 	 */
758 	error = xfs_rtmount_init(mp);
759 	if (error) {
760 		xfs_warn(mp, "RT mount failed");
761 		goto out_remove_uuid;
762 	}
763 
764 	/*
765 	 *  Copies the low order bits of the timestamp and the randomly
766 	 *  set "sequence" number out of a UUID.
767 	 */
768 	uuid_getnodeuniq(&sbp->sb_uuid, mp->m_fixedfsid);
769 
770 	mp->m_dmevmask = 0;	/* not persistent; set after each mount */
771 
772 	error = xfs_da_mount(mp);
773 	if (error) {
774 		xfs_warn(mp, "Failed dir/attr init: %d", error);
775 		goto out_remove_uuid;
776 	}
777 
778 	/*
779 	 * Initialize the precomputed transaction reservations values.
780 	 */
781 	xfs_trans_init(mp);
782 
783 	/*
784 	 * Allocate and initialize the per-ag data.
785 	 */
786 	spin_lock_init(&mp->m_perag_lock);
787 	INIT_RADIX_TREE(&mp->m_perag_tree, GFP_ATOMIC);
788 	error = xfs_initialize_perag(mp, sbp->sb_agcount, &mp->m_maxagi);
789 	if (error) {
790 		xfs_warn(mp, "Failed per-ag init: %d", error);
791 		goto out_free_dir;
792 	}
793 
794 	if (!sbp->sb_logblocks) {
795 		xfs_warn(mp, "no log defined");
796 		XFS_ERROR_REPORT("xfs_mountfs", XFS_ERRLEVEL_LOW, mp);
797 		error = -EFSCORRUPTED;
798 		goto out_free_perag;
799 	}
800 
801 	/*
802 	 * log's mount-time initialization. Perform 1st part recovery if needed
803 	 */
804 	error = xfs_log_mount(mp, mp->m_logdev_targp,
805 			      XFS_FSB_TO_DADDR(mp, sbp->sb_logstart),
806 			      XFS_FSB_TO_BB(mp, sbp->sb_logblocks));
807 	if (error) {
808 		xfs_warn(mp, "log mount failed");
809 		goto out_fail_wait;
810 	}
811 
812 	/*
813 	 * Now the log is mounted, we know if it was an unclean shutdown or
814 	 * not. If it was, with the first phase of recovery has completed, we
815 	 * have consistent AG blocks on disk. We have not recovered EFIs yet,
816 	 * but they are recovered transactionally in the second recovery phase
817 	 * later.
818 	 *
819 	 * Hence we can safely re-initialise incore superblock counters from
820 	 * the per-ag data. These may not be correct if the filesystem was not
821 	 * cleanly unmounted, so we need to wait for recovery to finish before
822 	 * doing this.
823 	 *
824 	 * If the filesystem was cleanly unmounted, then we can trust the
825 	 * values in the superblock to be correct and we don't need to do
826 	 * anything here.
827 	 *
828 	 * If we are currently making the filesystem, the initialisation will
829 	 * fail as the perag data is in an undefined state.
830 	 */
831 	if (xfs_sb_version_haslazysbcount(&mp->m_sb) &&
832 	    !XFS_LAST_UNMOUNT_WAS_CLEAN(mp) &&
833 	     !mp->m_sb.sb_inprogress) {
834 		error = xfs_initialize_perag_data(mp, sbp->sb_agcount);
835 		if (error)
836 			goto out_log_dealloc;
837 	}
838 
839 	/*
840 	 * Get and sanity-check the root inode.
841 	 * Save the pointer to it in the mount structure.
842 	 */
843 	error = xfs_iget(mp, NULL, sbp->sb_rootino, 0, XFS_ILOCK_EXCL, &rip);
844 	if (error) {
845 		xfs_warn(mp, "failed to read root inode");
846 		goto out_log_dealloc;
847 	}
848 
849 	ASSERT(rip != NULL);
850 
851 	if (unlikely(!S_ISDIR(rip->i_d.di_mode))) {
852 		xfs_warn(mp, "corrupted root inode %llu: not a directory",
853 			(unsigned long long)rip->i_ino);
854 		xfs_iunlock(rip, XFS_ILOCK_EXCL);
855 		XFS_ERROR_REPORT("xfs_mountfs_int(2)", XFS_ERRLEVEL_LOW,
856 				 mp);
857 		error = -EFSCORRUPTED;
858 		goto out_rele_rip;
859 	}
860 	mp->m_rootip = rip;	/* save it */
861 
862 	xfs_iunlock(rip, XFS_ILOCK_EXCL);
863 
864 	/*
865 	 * Initialize realtime inode pointers in the mount structure
866 	 */
867 	error = xfs_rtmount_inodes(mp);
868 	if (error) {
869 		/*
870 		 * Free up the root inode.
871 		 */
872 		xfs_warn(mp, "failed to read RT inodes");
873 		goto out_rele_rip;
874 	}
875 
876 	/*
877 	 * If this is a read-only mount defer the superblock updates until
878 	 * the next remount into writeable mode.  Otherwise we would never
879 	 * perform the update e.g. for the root filesystem.
880 	 */
881 	if (mp->m_update_sb && !(mp->m_flags & XFS_MOUNT_RDONLY)) {
882 		error = xfs_sync_sb(mp, false);
883 		if (error) {
884 			xfs_warn(mp, "failed to write sb changes");
885 			goto out_rtunmount;
886 		}
887 	}
888 
889 	/*
890 	 * Initialise the XFS quota management subsystem for this mount
891 	 */
892 	if (XFS_IS_QUOTA_RUNNING(mp)) {
893 		error = xfs_qm_newmount(mp, &quotamount, &quotaflags);
894 		if (error)
895 			goto out_rtunmount;
896 	} else {
897 		ASSERT(!XFS_IS_QUOTA_ON(mp));
898 
899 		/*
900 		 * If a file system had quotas running earlier, but decided to
901 		 * mount without -o uquota/pquota/gquota options, revoke the
902 		 * quotachecked license.
903 		 */
904 		if (mp->m_sb.sb_qflags & XFS_ALL_QUOTA_ACCT) {
905 			xfs_notice(mp, "resetting quota flags");
906 			error = xfs_mount_reset_sbqflags(mp);
907 			if (error)
908 				goto out_rtunmount;
909 		}
910 	}
911 
912 	/*
913 	 * Finish recovering the file system.  This part needed to be
914 	 * delayed until after the root and real-time bitmap inodes
915 	 * were consistently read in.
916 	 */
917 	error = xfs_log_mount_finish(mp);
918 	if (error) {
919 		xfs_warn(mp, "log mount finish failed");
920 		goto out_rtunmount;
921 	}
922 
923 	/*
924 	 * Complete the quota initialisation, post-log-replay component.
925 	 */
926 	if (quotamount) {
927 		ASSERT(mp->m_qflags == 0);
928 		mp->m_qflags = quotaflags;
929 
930 		xfs_qm_mount_quotas(mp);
931 	}
932 
933 	/*
934 	 * Now we are mounted, reserve a small amount of unused space for
935 	 * privileged transactions. This is needed so that transaction
936 	 * space required for critical operations can dip into this pool
937 	 * when at ENOSPC. This is needed for operations like create with
938 	 * attr, unwritten extent conversion at ENOSPC, etc. Data allocations
939 	 * are not allowed to use this reserved space.
940 	 *
941 	 * This may drive us straight to ENOSPC on mount, but that implies
942 	 * we were already there on the last unmount. Warn if this occurs.
943 	 */
944 	if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
945 		resblks = xfs_default_resblks(mp);
946 		error = xfs_reserve_blocks(mp, &resblks, NULL);
947 		if (error)
948 			xfs_warn(mp,
949 	"Unable to allocate reserve blocks. Continuing without reserve pool.");
950 	}
951 
952 	return 0;
953 
954  out_rtunmount:
955 	xfs_rtunmount_inodes(mp);
956  out_rele_rip:
957 	IRELE(rip);
958  out_log_dealloc:
959 	xfs_log_unmount(mp);
960  out_fail_wait:
961 	if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp)
962 		xfs_wait_buftarg(mp->m_logdev_targp);
963 	xfs_wait_buftarg(mp->m_ddev_targp);
964  out_free_perag:
965 	xfs_free_perag(mp);
966  out_free_dir:
967 	xfs_da_unmount(mp);
968  out_remove_uuid:
969 	xfs_uuid_unmount(mp);
970  out_remove_sysfs:
971 	xfs_sysfs_del(&mp->m_kobj);
972  out:
973 	return error;
974 }
975 
976 /*
977  * This flushes out the inodes,dquots and the superblock, unmounts the
978  * log and makes sure that incore structures are freed.
979  */
980 void
981 xfs_unmountfs(
982 	struct xfs_mount	*mp)
983 {
984 	__uint64_t		resblks;
985 	int			error;
986 
987 	cancel_delayed_work_sync(&mp->m_eofblocks_work);
988 
989 	xfs_qm_unmount_quotas(mp);
990 	xfs_rtunmount_inodes(mp);
991 	IRELE(mp->m_rootip);
992 
993 	/*
994 	 * We can potentially deadlock here if we have an inode cluster
995 	 * that has been freed has its buffer still pinned in memory because
996 	 * the transaction is still sitting in a iclog. The stale inodes
997 	 * on that buffer will have their flush locks held until the
998 	 * transaction hits the disk and the callbacks run. the inode
999 	 * flush takes the flush lock unconditionally and with nothing to
1000 	 * push out the iclog we will never get that unlocked. hence we
1001 	 * need to force the log first.
1002 	 */
1003 	xfs_log_force(mp, XFS_LOG_SYNC);
1004 
1005 	/*
1006 	 * Flush all pending changes from the AIL.
1007 	 */
1008 	xfs_ail_push_all_sync(mp->m_ail);
1009 
1010 	/*
1011 	 * And reclaim all inodes.  At this point there should be no dirty
1012 	 * inodes and none should be pinned or locked, but use synchronous
1013 	 * reclaim just to be sure. We can stop background inode reclaim
1014 	 * here as well if it is still running.
1015 	 */
1016 	cancel_delayed_work_sync(&mp->m_reclaim_work);
1017 	xfs_reclaim_inodes(mp, SYNC_WAIT);
1018 
1019 	xfs_qm_unmount(mp);
1020 
1021 	/*
1022 	 * Unreserve any blocks we have so that when we unmount we don't account
1023 	 * the reserved free space as used. This is really only necessary for
1024 	 * lazy superblock counting because it trusts the incore superblock
1025 	 * counters to be absolutely correct on clean unmount.
1026 	 *
1027 	 * We don't bother correcting this elsewhere for lazy superblock
1028 	 * counting because on mount of an unclean filesystem we reconstruct the
1029 	 * correct counter value and this is irrelevant.
1030 	 *
1031 	 * For non-lazy counter filesystems, this doesn't matter at all because
1032 	 * we only every apply deltas to the superblock and hence the incore
1033 	 * value does not matter....
1034 	 */
1035 	resblks = 0;
1036 	error = xfs_reserve_blocks(mp, &resblks, NULL);
1037 	if (error)
1038 		xfs_warn(mp, "Unable to free reserved block pool. "
1039 				"Freespace may not be correct on next mount.");
1040 
1041 	error = xfs_log_sbcount(mp);
1042 	if (error)
1043 		xfs_warn(mp, "Unable to update superblock counters. "
1044 				"Freespace may not be correct on next mount.");
1045 
1046 	xfs_log_unmount(mp);
1047 	xfs_da_unmount(mp);
1048 	xfs_uuid_unmount(mp);
1049 
1050 #if defined(DEBUG)
1051 	xfs_errortag_clearall(mp, 0);
1052 #endif
1053 	xfs_free_perag(mp);
1054 
1055 	xfs_sysfs_del(&mp->m_kobj);
1056 }
1057 
1058 /*
1059  * Determine whether modifications can proceed. The caller specifies the minimum
1060  * freeze level for which modifications should not be allowed. This allows
1061  * certain operations to proceed while the freeze sequence is in progress, if
1062  * necessary.
1063  */
1064 bool
1065 xfs_fs_writable(
1066 	struct xfs_mount	*mp,
1067 	int			level)
1068 {
1069 	ASSERT(level > SB_UNFROZEN);
1070 	if ((mp->m_super->s_writers.frozen >= level) ||
1071 	    XFS_FORCED_SHUTDOWN(mp) || (mp->m_flags & XFS_MOUNT_RDONLY))
1072 		return false;
1073 
1074 	return true;
1075 }
1076 
1077 /*
1078  * xfs_log_sbcount
1079  *
1080  * Sync the superblock counters to disk.
1081  *
1082  * Note this code can be called during the process of freezing, so we use the
1083  * transaction allocator that does not block when the transaction subsystem is
1084  * in its frozen state.
1085  */
1086 int
1087 xfs_log_sbcount(xfs_mount_t *mp)
1088 {
1089 	/* allow this to proceed during the freeze sequence... */
1090 	if (!xfs_fs_writable(mp, SB_FREEZE_COMPLETE))
1091 		return 0;
1092 
1093 	/*
1094 	 * we don't need to do this if we are updating the superblock
1095 	 * counters on every modification.
1096 	 */
1097 	if (!xfs_sb_version_haslazysbcount(&mp->m_sb))
1098 		return 0;
1099 
1100 	return xfs_sync_sb(mp, true);
1101 }
1102 
1103 /*
1104  * Deltas for the inode count are +/-64, hence we use a large batch size
1105  * of 128 so we don't need to take the counter lock on every update.
1106  */
1107 #define XFS_ICOUNT_BATCH	128
1108 int
1109 xfs_mod_icount(
1110 	struct xfs_mount	*mp,
1111 	int64_t			delta)
1112 {
1113 	__percpu_counter_add(&mp->m_icount, delta, XFS_ICOUNT_BATCH);
1114 	if (__percpu_counter_compare(&mp->m_icount, 0, XFS_ICOUNT_BATCH) < 0) {
1115 		ASSERT(0);
1116 		percpu_counter_add(&mp->m_icount, -delta);
1117 		return -EINVAL;
1118 	}
1119 	return 0;
1120 }
1121 
1122 int
1123 xfs_mod_ifree(
1124 	struct xfs_mount	*mp,
1125 	int64_t			delta)
1126 {
1127 	percpu_counter_add(&mp->m_ifree, delta);
1128 	if (percpu_counter_compare(&mp->m_ifree, 0) < 0) {
1129 		ASSERT(0);
1130 		percpu_counter_add(&mp->m_ifree, -delta);
1131 		return -EINVAL;
1132 	}
1133 	return 0;
1134 }
1135 
1136 /*
1137  * Deltas for the block count can vary from 1 to very large, but lock contention
1138  * only occurs on frequent small block count updates such as in the delayed
1139  * allocation path for buffered writes (page a time updates). Hence we set
1140  * a large batch count (1024) to minimise global counter updates except when
1141  * we get near to ENOSPC and we have to be very accurate with our updates.
1142  */
1143 #define XFS_FDBLOCKS_BATCH	1024
1144 int
1145 xfs_mod_fdblocks(
1146 	struct xfs_mount	*mp,
1147 	int64_t			delta,
1148 	bool			rsvd)
1149 {
1150 	int64_t			lcounter;
1151 	long long		res_used;
1152 	s32			batch;
1153 
1154 	if (delta > 0) {
1155 		/*
1156 		 * If the reserve pool is depleted, put blocks back into it
1157 		 * first. Most of the time the pool is full.
1158 		 */
1159 		if (likely(mp->m_resblks == mp->m_resblks_avail)) {
1160 			percpu_counter_add(&mp->m_fdblocks, delta);
1161 			return 0;
1162 		}
1163 
1164 		spin_lock(&mp->m_sb_lock);
1165 		res_used = (long long)(mp->m_resblks - mp->m_resblks_avail);
1166 
1167 		if (res_used > delta) {
1168 			mp->m_resblks_avail += delta;
1169 		} else {
1170 			delta -= res_used;
1171 			mp->m_resblks_avail = mp->m_resblks;
1172 			percpu_counter_add(&mp->m_fdblocks, delta);
1173 		}
1174 		spin_unlock(&mp->m_sb_lock);
1175 		return 0;
1176 	}
1177 
1178 	/*
1179 	 * Taking blocks away, need to be more accurate the closer we
1180 	 * are to zero.
1181 	 *
1182 	 * If the counter has a value of less than 2 * max batch size,
1183 	 * then make everything serialise as we are real close to
1184 	 * ENOSPC.
1185 	 */
1186 	if (__percpu_counter_compare(&mp->m_fdblocks, 2 * XFS_FDBLOCKS_BATCH,
1187 				     XFS_FDBLOCKS_BATCH) < 0)
1188 		batch = 1;
1189 	else
1190 		batch = XFS_FDBLOCKS_BATCH;
1191 
1192 	__percpu_counter_add(&mp->m_fdblocks, delta, batch);
1193 	if (__percpu_counter_compare(&mp->m_fdblocks, XFS_ALLOC_SET_ASIDE(mp),
1194 				     XFS_FDBLOCKS_BATCH) >= 0) {
1195 		/* we had space! */
1196 		return 0;
1197 	}
1198 
1199 	/*
1200 	 * lock up the sb for dipping into reserves before releasing the space
1201 	 * that took us to ENOSPC.
1202 	 */
1203 	spin_lock(&mp->m_sb_lock);
1204 	percpu_counter_add(&mp->m_fdblocks, -delta);
1205 	if (!rsvd)
1206 		goto fdblocks_enospc;
1207 
1208 	lcounter = (long long)mp->m_resblks_avail + delta;
1209 	if (lcounter >= 0) {
1210 		mp->m_resblks_avail = lcounter;
1211 		spin_unlock(&mp->m_sb_lock);
1212 		return 0;
1213 	}
1214 	printk_once(KERN_WARNING
1215 		"Filesystem \"%s\": reserve blocks depleted! "
1216 		"Consider increasing reserve pool size.",
1217 		mp->m_fsname);
1218 fdblocks_enospc:
1219 	spin_unlock(&mp->m_sb_lock);
1220 	return -ENOSPC;
1221 }
1222 
1223 int
1224 xfs_mod_frextents(
1225 	struct xfs_mount	*mp,
1226 	int64_t			delta)
1227 {
1228 	int64_t			lcounter;
1229 	int			ret = 0;
1230 
1231 	spin_lock(&mp->m_sb_lock);
1232 	lcounter = mp->m_sb.sb_frextents + delta;
1233 	if (lcounter < 0)
1234 		ret = -ENOSPC;
1235 	else
1236 		mp->m_sb.sb_frextents = lcounter;
1237 	spin_unlock(&mp->m_sb_lock);
1238 	return ret;
1239 }
1240 
1241 /*
1242  * xfs_getsb() is called to obtain the buffer for the superblock.
1243  * The buffer is returned locked and read in from disk.
1244  * The buffer should be released with a call to xfs_brelse().
1245  *
1246  * If the flags parameter is BUF_TRYLOCK, then we'll only return
1247  * the superblock buffer if it can be locked without sleeping.
1248  * If it can't then we'll return NULL.
1249  */
1250 struct xfs_buf *
1251 xfs_getsb(
1252 	struct xfs_mount	*mp,
1253 	int			flags)
1254 {
1255 	struct xfs_buf		*bp = mp->m_sb_bp;
1256 
1257 	if (!xfs_buf_trylock(bp)) {
1258 		if (flags & XBF_TRYLOCK)
1259 			return NULL;
1260 		xfs_buf_lock(bp);
1261 	}
1262 
1263 	xfs_buf_hold(bp);
1264 	ASSERT(XFS_BUF_ISDONE(bp));
1265 	return bp;
1266 }
1267 
1268 /*
1269  * Used to free the superblock along various error paths.
1270  */
1271 void
1272 xfs_freesb(
1273 	struct xfs_mount	*mp)
1274 {
1275 	struct xfs_buf		*bp = mp->m_sb_bp;
1276 
1277 	xfs_buf_lock(bp);
1278 	mp->m_sb_bp = NULL;
1279 	xfs_buf_relse(bp);
1280 }
1281 
1282 /*
1283  * If the underlying (data/log/rt) device is readonly, there are some
1284  * operations that cannot proceed.
1285  */
1286 int
1287 xfs_dev_is_read_only(
1288 	struct xfs_mount	*mp,
1289 	char			*message)
1290 {
1291 	if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
1292 	    xfs_readonly_buftarg(mp->m_logdev_targp) ||
1293 	    (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
1294 		xfs_notice(mp, "%s required on read-only device.", message);
1295 		xfs_notice(mp, "write access unavailable, cannot proceed.");
1296 		return -EROFS;
1297 	}
1298 	return 0;
1299 }
1300