xref: /linux/fs/xfs/xfs_mount.c (revision de2fe5e07d58424bc286fff3fd3c1b0bf933cd58)
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_log.h"
23 #include "xfs_inum.h"
24 #include "xfs_trans.h"
25 #include "xfs_sb.h"
26 #include "xfs_ag.h"
27 #include "xfs_dir.h"
28 #include "xfs_dir2.h"
29 #include "xfs_dmapi.h"
30 #include "xfs_mount.h"
31 #include "xfs_bmap_btree.h"
32 #include "xfs_alloc_btree.h"
33 #include "xfs_ialloc_btree.h"
34 #include "xfs_dir_sf.h"
35 #include "xfs_dir2_sf.h"
36 #include "xfs_attr_sf.h"
37 #include "xfs_dinode.h"
38 #include "xfs_inode.h"
39 #include "xfs_btree.h"
40 #include "xfs_ialloc.h"
41 #include "xfs_alloc.h"
42 #include "xfs_rtalloc.h"
43 #include "xfs_bmap.h"
44 #include "xfs_error.h"
45 #include "xfs_rw.h"
46 #include "xfs_quota.h"
47 #include "xfs_fsops.h"
48 
49 STATIC void	xfs_mount_log_sbunit(xfs_mount_t *, __int64_t);
50 STATIC int	xfs_uuid_mount(xfs_mount_t *);
51 STATIC void	xfs_uuid_unmount(xfs_mount_t *mp);
52 STATIC void	xfs_unmountfs_wait(xfs_mount_t *);
53 
54 
55 #ifdef HAVE_PERCPU_SB
56 STATIC void	xfs_icsb_destroy_counters(xfs_mount_t *);
57 STATIC void	xfs_icsb_balance_counter(xfs_mount_t *, xfs_sb_field_t, int);
58 STATIC void	xfs_icsb_sync_counters(xfs_mount_t *);
59 STATIC int	xfs_icsb_modify_counters(xfs_mount_t *, xfs_sb_field_t,
60 						int, int);
61 STATIC int	xfs_icsb_modify_counters_locked(xfs_mount_t *, xfs_sb_field_t,
62 						int, int);
63 STATIC int	xfs_icsb_disable_counter(xfs_mount_t *, xfs_sb_field_t);
64 
65 #else
66 
67 #define xfs_icsb_destroy_counters(mp)			do { } while (0)
68 #define xfs_icsb_balance_counter(mp, a, b)		do { } while (0)
69 #define xfs_icsb_sync_counters(mp)			do { } while (0)
70 #define xfs_icsb_modify_counters(mp, a, b, c)		do { } while (0)
71 #define xfs_icsb_modify_counters_locked(mp, a, b, c)	do { } while (0)
72 
73 #endif
74 
75 static const struct {
76 	short offset;
77 	short type;	/* 0 = integer
78 			 * 1 = binary / string (no translation)
79 			 */
80 } xfs_sb_info[] = {
81     { offsetof(xfs_sb_t, sb_magicnum),   0 },
82     { offsetof(xfs_sb_t, sb_blocksize),  0 },
83     { offsetof(xfs_sb_t, sb_dblocks),    0 },
84     { offsetof(xfs_sb_t, sb_rblocks),    0 },
85     { offsetof(xfs_sb_t, sb_rextents),   0 },
86     { offsetof(xfs_sb_t, sb_uuid),       1 },
87     { offsetof(xfs_sb_t, sb_logstart),   0 },
88     { offsetof(xfs_sb_t, sb_rootino),    0 },
89     { offsetof(xfs_sb_t, sb_rbmino),     0 },
90     { offsetof(xfs_sb_t, sb_rsumino),    0 },
91     { offsetof(xfs_sb_t, sb_rextsize),   0 },
92     { offsetof(xfs_sb_t, sb_agblocks),   0 },
93     { offsetof(xfs_sb_t, sb_agcount),    0 },
94     { offsetof(xfs_sb_t, sb_rbmblocks),  0 },
95     { offsetof(xfs_sb_t, sb_logblocks),  0 },
96     { offsetof(xfs_sb_t, sb_versionnum), 0 },
97     { offsetof(xfs_sb_t, sb_sectsize),   0 },
98     { offsetof(xfs_sb_t, sb_inodesize),  0 },
99     { offsetof(xfs_sb_t, sb_inopblock),  0 },
100     { offsetof(xfs_sb_t, sb_fname[0]),   1 },
101     { offsetof(xfs_sb_t, sb_blocklog),   0 },
102     { offsetof(xfs_sb_t, sb_sectlog),    0 },
103     { offsetof(xfs_sb_t, sb_inodelog),   0 },
104     { offsetof(xfs_sb_t, sb_inopblog),   0 },
105     { offsetof(xfs_sb_t, sb_agblklog),   0 },
106     { offsetof(xfs_sb_t, sb_rextslog),   0 },
107     { offsetof(xfs_sb_t, sb_inprogress), 0 },
108     { offsetof(xfs_sb_t, sb_imax_pct),   0 },
109     { offsetof(xfs_sb_t, sb_icount),     0 },
110     { offsetof(xfs_sb_t, sb_ifree),      0 },
111     { offsetof(xfs_sb_t, sb_fdblocks),   0 },
112     { offsetof(xfs_sb_t, sb_frextents),  0 },
113     { offsetof(xfs_sb_t, sb_uquotino),   0 },
114     { offsetof(xfs_sb_t, sb_gquotino),   0 },
115     { offsetof(xfs_sb_t, sb_qflags),     0 },
116     { offsetof(xfs_sb_t, sb_flags),      0 },
117     { offsetof(xfs_sb_t, sb_shared_vn),  0 },
118     { offsetof(xfs_sb_t, sb_inoalignmt), 0 },
119     { offsetof(xfs_sb_t, sb_unit),	 0 },
120     { offsetof(xfs_sb_t, sb_width),	 0 },
121     { offsetof(xfs_sb_t, sb_dirblklog),	 0 },
122     { offsetof(xfs_sb_t, sb_logsectlog), 0 },
123     { offsetof(xfs_sb_t, sb_logsectsize),0 },
124     { offsetof(xfs_sb_t, sb_logsunit),	 0 },
125     { offsetof(xfs_sb_t, sb_features2),	 0 },
126     { sizeof(xfs_sb_t),			 0 }
127 };
128 
129 /*
130  * Return a pointer to an initialized xfs_mount structure.
131  */
132 xfs_mount_t *
133 xfs_mount_init(void)
134 {
135 	xfs_mount_t *mp;
136 
137 	mp = kmem_zalloc(sizeof(xfs_mount_t), KM_SLEEP);
138 
139 	if (xfs_icsb_init_counters(mp)) {
140 		mp->m_flags |= XFS_MOUNT_NO_PERCPU_SB;
141 	}
142 
143 	AIL_LOCKINIT(&mp->m_ail_lock, "xfs_ail");
144 	spinlock_init(&mp->m_sb_lock, "xfs_sb");
145 	mutex_init(&mp->m_ilock);
146 	initnsema(&mp->m_growlock, 1, "xfs_grow");
147 	/*
148 	 * Initialize the AIL.
149 	 */
150 	xfs_trans_ail_init(mp);
151 
152 	atomic_set(&mp->m_active_trans, 0);
153 
154 	return mp;
155 }
156 
157 /*
158  * Free up the resources associated with a mount structure.  Assume that
159  * the structure was initially zeroed, so we can tell which fields got
160  * initialized.
161  */
162 void
163 xfs_mount_free(
164 	xfs_mount_t	*mp,
165 	int		remove_bhv)
166 {
167 	if (mp->m_ihash)
168 		xfs_ihash_free(mp);
169 	if (mp->m_chash)
170 		xfs_chash_free(mp);
171 
172 	if (mp->m_perag) {
173 		int	agno;
174 
175 		for (agno = 0; agno < mp->m_maxagi; agno++)
176 			if (mp->m_perag[agno].pagb_list)
177 				kmem_free(mp->m_perag[agno].pagb_list,
178 						sizeof(xfs_perag_busy_t) *
179 							XFS_PAGB_NUM_SLOTS);
180 		kmem_free(mp->m_perag,
181 			  sizeof(xfs_perag_t) * mp->m_sb.sb_agcount);
182 	}
183 
184 	AIL_LOCK_DESTROY(&mp->m_ail_lock);
185 	spinlock_destroy(&mp->m_sb_lock);
186 	mutex_destroy(&mp->m_ilock);
187 	freesema(&mp->m_growlock);
188 	if (mp->m_quotainfo)
189 		XFS_QM_DONE(mp);
190 
191 	if (mp->m_fsname != NULL)
192 		kmem_free(mp->m_fsname, mp->m_fsname_len);
193 	if (mp->m_rtname != NULL)
194 		kmem_free(mp->m_rtname, strlen(mp->m_rtname) + 1);
195 	if (mp->m_logname != NULL)
196 		kmem_free(mp->m_logname, strlen(mp->m_logname) + 1);
197 
198 	if (remove_bhv) {
199 		struct vfs	*vfsp = XFS_MTOVFS(mp);
200 
201 		bhv_remove_all_vfsops(vfsp, 0);
202 		VFS_REMOVEBHV(vfsp, &mp->m_bhv);
203 	}
204 
205 	xfs_icsb_destroy_counters(mp);
206 	kmem_free(mp, sizeof(xfs_mount_t));
207 }
208 
209 
210 /*
211  * Check the validity of the SB found.
212  */
213 STATIC int
214 xfs_mount_validate_sb(
215 	xfs_mount_t	*mp,
216 	xfs_sb_t	*sbp)
217 {
218 	/*
219 	 * If the log device and data device have the
220 	 * same device number, the log is internal.
221 	 * Consequently, the sb_logstart should be non-zero.  If
222 	 * we have a zero sb_logstart in this case, we may be trying to mount
223 	 * a volume filesystem in a non-volume manner.
224 	 */
225 	if (sbp->sb_magicnum != XFS_SB_MAGIC) {
226 		cmn_err(CE_WARN, "XFS: bad magic number");
227 		return XFS_ERROR(EWRONGFS);
228 	}
229 
230 	if (!XFS_SB_GOOD_VERSION(sbp)) {
231 		cmn_err(CE_WARN, "XFS: bad version");
232 		return XFS_ERROR(EWRONGFS);
233 	}
234 
235 	if (unlikely(
236 	    sbp->sb_logstart == 0 && mp->m_logdev_targp == mp->m_ddev_targp)) {
237 		cmn_err(CE_WARN,
238 	"XFS: filesystem is marked as having an external log; "
239 	"specify logdev on the\nmount command line.");
240 		XFS_CORRUPTION_ERROR("xfs_mount_validate_sb(1)",
241 				     XFS_ERRLEVEL_HIGH, mp, sbp);
242 		return XFS_ERROR(EFSCORRUPTED);
243 	}
244 
245 	if (unlikely(
246 	    sbp->sb_logstart != 0 && mp->m_logdev_targp != mp->m_ddev_targp)) {
247 		cmn_err(CE_WARN,
248 	"XFS: filesystem is marked as having an internal log; "
249 	"don't specify logdev on\nthe mount command line.");
250 		XFS_CORRUPTION_ERROR("xfs_mount_validate_sb(2)",
251 				     XFS_ERRLEVEL_HIGH, mp, sbp);
252 		return XFS_ERROR(EFSCORRUPTED);
253 	}
254 
255 	/*
256 	 * More sanity checking. These were stolen directly from
257 	 * xfs_repair.
258 	 */
259 	if (unlikely(
260 	    sbp->sb_agcount <= 0					||
261 	    sbp->sb_sectsize < XFS_MIN_SECTORSIZE			||
262 	    sbp->sb_sectsize > XFS_MAX_SECTORSIZE			||
263 	    sbp->sb_sectlog < XFS_MIN_SECTORSIZE_LOG			||
264 	    sbp->sb_sectlog > XFS_MAX_SECTORSIZE_LOG			||
265 	    sbp->sb_blocksize < XFS_MIN_BLOCKSIZE			||
266 	    sbp->sb_blocksize > XFS_MAX_BLOCKSIZE			||
267 	    sbp->sb_blocklog < XFS_MIN_BLOCKSIZE_LOG			||
268 	    sbp->sb_blocklog > XFS_MAX_BLOCKSIZE_LOG			||
269 	    sbp->sb_inodesize < XFS_DINODE_MIN_SIZE			||
270 	    sbp->sb_inodesize > XFS_DINODE_MAX_SIZE			||
271 	    sbp->sb_inodelog < XFS_DINODE_MIN_LOG			||
272 	    sbp->sb_inodelog > XFS_DINODE_MAX_LOG			||
273 	    (sbp->sb_blocklog - sbp->sb_inodelog != sbp->sb_inopblog)	||
274 	    (sbp->sb_rextsize * sbp->sb_blocksize > XFS_MAX_RTEXTSIZE)	||
275 	    (sbp->sb_rextsize * sbp->sb_blocksize < XFS_MIN_RTEXTSIZE)	||
276 	    (sbp->sb_imax_pct > 100 || sbp->sb_imax_pct < 1))) {
277 		cmn_err(CE_WARN, "XFS: SB sanity check 1 failed");
278 		XFS_CORRUPTION_ERROR("xfs_mount_validate_sb(3)",
279 				     XFS_ERRLEVEL_LOW, mp, sbp);
280 		return XFS_ERROR(EFSCORRUPTED);
281 	}
282 
283 	/*
284 	 * Sanity check AG count, size fields against data size field
285 	 */
286 	if (unlikely(
287 	    sbp->sb_dblocks == 0 ||
288 	    sbp->sb_dblocks >
289 	     (xfs_drfsbno_t)sbp->sb_agcount * sbp->sb_agblocks ||
290 	    sbp->sb_dblocks < (xfs_drfsbno_t)(sbp->sb_agcount - 1) *
291 			      sbp->sb_agblocks + XFS_MIN_AG_BLOCKS)) {
292 		cmn_err(CE_WARN, "XFS: SB sanity check 2 failed");
293 		XFS_ERROR_REPORT("xfs_mount_validate_sb(4)",
294 				 XFS_ERRLEVEL_LOW, mp);
295 		return XFS_ERROR(EFSCORRUPTED);
296 	}
297 
298 	ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
299 	ASSERT(sbp->sb_blocklog >= BBSHIFT);
300 
301 #if XFS_BIG_BLKNOS     /* Limited by ULONG_MAX of page cache index */
302 	if (unlikely(
303 	    (sbp->sb_dblocks >> (PAGE_SHIFT - sbp->sb_blocklog)) > ULONG_MAX ||
304 	    (sbp->sb_rblocks >> (PAGE_SHIFT - sbp->sb_blocklog)) > ULONG_MAX)) {
305 #else                  /* Limited by UINT_MAX of sectors */
306 	if (unlikely(
307 	    (sbp->sb_dblocks << (sbp->sb_blocklog - BBSHIFT)) > UINT_MAX ||
308 	    (sbp->sb_rblocks << (sbp->sb_blocklog - BBSHIFT)) > UINT_MAX)) {
309 #endif
310 		cmn_err(CE_WARN,
311 	"XFS: File system is too large to be mounted on this system.");
312 		return XFS_ERROR(E2BIG);
313 	}
314 
315 	if (unlikely(sbp->sb_inprogress)) {
316 		cmn_err(CE_WARN, "XFS: file system busy");
317 		XFS_ERROR_REPORT("xfs_mount_validate_sb(5)",
318 				 XFS_ERRLEVEL_LOW, mp);
319 		return XFS_ERROR(EFSCORRUPTED);
320 	}
321 
322 	/*
323 	 * Version 1 directory format has never worked on Linux.
324 	 */
325 	if (unlikely(!XFS_SB_VERSION_HASDIRV2(sbp))) {
326 		cmn_err(CE_WARN,
327 	"XFS: Attempted to mount file system using version 1 directory format");
328 		return XFS_ERROR(ENOSYS);
329 	}
330 
331 	/*
332 	 * Until this is fixed only page-sized or smaller data blocks work.
333 	 */
334 	if (unlikely(sbp->sb_blocksize > PAGE_SIZE)) {
335 		cmn_err(CE_WARN,
336 		"XFS: Attempted to mount file system with blocksize %d bytes",
337 			sbp->sb_blocksize);
338 		cmn_err(CE_WARN,
339 		"XFS: Only page-sized (%ld) or less blocksizes currently work.",
340 			PAGE_SIZE);
341 		return XFS_ERROR(ENOSYS);
342 	}
343 
344 	return 0;
345 }
346 
347 xfs_agnumber_t
348 xfs_initialize_perag(
349 	struct vfs	*vfs,
350 	xfs_mount_t	*mp,
351 	xfs_agnumber_t	agcount)
352 {
353 	xfs_agnumber_t	index, max_metadata;
354 	xfs_perag_t	*pag;
355 	xfs_agino_t	agino;
356 	xfs_ino_t	ino;
357 	xfs_sb_t	*sbp = &mp->m_sb;
358 	xfs_ino_t	max_inum = XFS_MAXINUMBER_32;
359 
360 	/* Check to see if the filesystem can overflow 32 bit inodes */
361 	agino = XFS_OFFBNO_TO_AGINO(mp, sbp->sb_agblocks - 1, 0);
362 	ino = XFS_AGINO_TO_INO(mp, agcount - 1, agino);
363 
364 	/* Clear the mount flag if no inode can overflow 32 bits
365 	 * on this filesystem, or if specifically requested..
366 	 */
367 	if ((vfs->vfs_flag & VFS_32BITINODES) && ino > max_inum) {
368 		mp->m_flags |= XFS_MOUNT_32BITINODES;
369 	} else {
370 		mp->m_flags &= ~XFS_MOUNT_32BITINODES;
371 	}
372 
373 	/* If we can overflow then setup the ag headers accordingly */
374 	if (mp->m_flags & XFS_MOUNT_32BITINODES) {
375 		/* Calculate how much should be reserved for inodes to
376 		 * meet the max inode percentage.
377 		 */
378 		if (mp->m_maxicount) {
379 			__uint64_t	icount;
380 
381 			icount = sbp->sb_dblocks * sbp->sb_imax_pct;
382 			do_div(icount, 100);
383 			icount += sbp->sb_agblocks - 1;
384 			do_div(icount, sbp->sb_agblocks);
385 			max_metadata = icount;
386 		} else {
387 			max_metadata = agcount;
388 		}
389 		for (index = 0; index < agcount; index++) {
390 			ino = XFS_AGINO_TO_INO(mp, index, agino);
391 			if (ino > max_inum) {
392 				index++;
393 				break;
394 			}
395 
396 			/* This ag is preferred for inodes */
397 			pag = &mp->m_perag[index];
398 			pag->pagi_inodeok = 1;
399 			if (index < max_metadata)
400 				pag->pagf_metadata = 1;
401 		}
402 	} else {
403 		/* Setup default behavior for smaller filesystems */
404 		for (index = 0; index < agcount; index++) {
405 			pag = &mp->m_perag[index];
406 			pag->pagi_inodeok = 1;
407 		}
408 	}
409 	return index;
410 }
411 
412 /*
413  * xfs_xlatesb
414  *
415  *     data       - on disk version of sb
416  *     sb         - a superblock
417  *     dir        - conversion direction: <0 - convert sb to buf
418  *                                        >0 - convert buf to sb
419  *     fields     - which fields to copy (bitmask)
420  */
421 void
422 xfs_xlatesb(
423 	void		*data,
424 	xfs_sb_t	*sb,
425 	int		dir,
426 	__int64_t	fields)
427 {
428 	xfs_caddr_t	buf_ptr;
429 	xfs_caddr_t	mem_ptr;
430 	xfs_sb_field_t	f;
431 	int		first;
432 	int		size;
433 
434 	ASSERT(dir);
435 	ASSERT(fields);
436 
437 	if (!fields)
438 		return;
439 
440 	buf_ptr = (xfs_caddr_t)data;
441 	mem_ptr = (xfs_caddr_t)sb;
442 
443 	while (fields) {
444 		f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
445 		first = xfs_sb_info[f].offset;
446 		size = xfs_sb_info[f + 1].offset - first;
447 
448 		ASSERT(xfs_sb_info[f].type == 0 || xfs_sb_info[f].type == 1);
449 
450 		if (size == 1 || xfs_sb_info[f].type == 1) {
451 			if (dir > 0) {
452 				memcpy(mem_ptr + first, buf_ptr + first, size);
453 			} else {
454 				memcpy(buf_ptr + first, mem_ptr + first, size);
455 			}
456 		} else {
457 			switch (size) {
458 			case 2:
459 				INT_XLATE(*(__uint16_t*)(buf_ptr+first),
460 					  *(__uint16_t*)(mem_ptr+first),
461 					  dir, ARCH_CONVERT);
462 				break;
463 			case 4:
464 				INT_XLATE(*(__uint32_t*)(buf_ptr+first),
465 					  *(__uint32_t*)(mem_ptr+first),
466 					  dir, ARCH_CONVERT);
467 				break;
468 			case 8:
469 				INT_XLATE(*(__uint64_t*)(buf_ptr+first),
470 					  *(__uint64_t*)(mem_ptr+first), dir, ARCH_CONVERT);
471 				break;
472 			default:
473 				ASSERT(0);
474 			}
475 		}
476 
477 		fields &= ~(1LL << f);
478 	}
479 }
480 
481 /*
482  * xfs_readsb
483  *
484  * Does the initial read of the superblock.
485  */
486 int
487 xfs_readsb(xfs_mount_t *mp)
488 {
489 	unsigned int	sector_size;
490 	unsigned int	extra_flags;
491 	xfs_buf_t	*bp;
492 	xfs_sb_t	*sbp;
493 	int		error;
494 
495 	ASSERT(mp->m_sb_bp == NULL);
496 	ASSERT(mp->m_ddev_targp != NULL);
497 
498 	/*
499 	 * Allocate a (locked) buffer to hold the superblock.
500 	 * This will be kept around at all times to optimize
501 	 * access to the superblock.
502 	 */
503 	sector_size = xfs_getsize_buftarg(mp->m_ddev_targp);
504 	extra_flags = XFS_BUF_LOCK | XFS_BUF_MANAGE | XFS_BUF_MAPPED;
505 
506 	bp = xfs_buf_read_flags(mp->m_ddev_targp, XFS_SB_DADDR,
507 				BTOBB(sector_size), extra_flags);
508 	if (!bp || XFS_BUF_ISERROR(bp)) {
509 		cmn_err(CE_WARN, "XFS: SB read failed");
510 		error = bp ? XFS_BUF_GETERROR(bp) : ENOMEM;
511 		goto fail;
512 	}
513 	ASSERT(XFS_BUF_ISBUSY(bp));
514 	ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
515 
516 	/*
517 	 * Initialize the mount structure from the superblock.
518 	 * But first do some basic consistency checking.
519 	 */
520 	sbp = XFS_BUF_TO_SBP(bp);
521 	xfs_xlatesb(XFS_BUF_PTR(bp), &(mp->m_sb), 1, XFS_SB_ALL_BITS);
522 
523 	error = xfs_mount_validate_sb(mp, &(mp->m_sb));
524 	if (error) {
525 		cmn_err(CE_WARN, "XFS: SB validate failed");
526 		goto fail;
527 	}
528 
529 	/*
530 	 * We must be able to do sector-sized and sector-aligned IO.
531 	 */
532 	if (sector_size > mp->m_sb.sb_sectsize) {
533 		cmn_err(CE_WARN,
534 			"XFS: device supports only %u byte sectors (not %u)",
535 			sector_size, mp->m_sb.sb_sectsize);
536 		error = ENOSYS;
537 		goto fail;
538 	}
539 
540 	/*
541 	 * If device sector size is smaller than the superblock size,
542 	 * re-read the superblock so the buffer is correctly sized.
543 	 */
544 	if (sector_size < mp->m_sb.sb_sectsize) {
545 		XFS_BUF_UNMANAGE(bp);
546 		xfs_buf_relse(bp);
547 		sector_size = mp->m_sb.sb_sectsize;
548 		bp = xfs_buf_read_flags(mp->m_ddev_targp, XFS_SB_DADDR,
549 					BTOBB(sector_size), extra_flags);
550 		if (!bp || XFS_BUF_ISERROR(bp)) {
551 			cmn_err(CE_WARN, "XFS: SB re-read failed");
552 			error = bp ? XFS_BUF_GETERROR(bp) : ENOMEM;
553 			goto fail;
554 		}
555 		ASSERT(XFS_BUF_ISBUSY(bp));
556 		ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
557 	}
558 
559 	xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0);
560 	xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0);
561 	xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0);
562 
563 	mp->m_sb_bp = bp;
564 	xfs_buf_relse(bp);
565 	ASSERT(XFS_BUF_VALUSEMA(bp) > 0);
566 	return 0;
567 
568  fail:
569 	if (bp) {
570 		XFS_BUF_UNMANAGE(bp);
571 		xfs_buf_relse(bp);
572 	}
573 	return error;
574 }
575 
576 
577 /*
578  * xfs_mount_common
579  *
580  * Mount initialization code establishing various mount
581  * fields from the superblock associated with the given
582  * mount structure
583  */
584 STATIC void
585 xfs_mount_common(xfs_mount_t *mp, xfs_sb_t *sbp)
586 {
587 	int	i;
588 
589 	mp->m_agfrotor = mp->m_agirotor = 0;
590 	spinlock_init(&mp->m_agirotor_lock, "m_agirotor_lock");
591 	mp->m_maxagi = mp->m_sb.sb_agcount;
592 	mp->m_blkbit_log = sbp->sb_blocklog + XFS_NBBYLOG;
593 	mp->m_blkbb_log = sbp->sb_blocklog - BBSHIFT;
594 	mp->m_sectbb_log = sbp->sb_sectlog - BBSHIFT;
595 	mp->m_agno_log = xfs_highbit32(sbp->sb_agcount - 1) + 1;
596 	mp->m_agino_log = sbp->sb_inopblog + sbp->sb_agblklog;
597 	mp->m_litino = sbp->sb_inodesize -
598 		((uint)sizeof(xfs_dinode_core_t) + (uint)sizeof(xfs_agino_t));
599 	mp->m_blockmask = sbp->sb_blocksize - 1;
600 	mp->m_blockwsize = sbp->sb_blocksize >> XFS_WORDLOG;
601 	mp->m_blockwmask = mp->m_blockwsize - 1;
602 	INIT_LIST_HEAD(&mp->m_del_inodes);
603 
604 	/*
605 	 * Setup for attributes, in case they get created.
606 	 * This value is for inodes getting attributes for the first time,
607 	 * the per-inode value is for old attribute values.
608 	 */
609 	ASSERT(sbp->sb_inodesize >= 256 && sbp->sb_inodesize <= 2048);
610 	switch (sbp->sb_inodesize) {
611 	case 256:
612 		mp->m_attroffset = XFS_LITINO(mp) -
613 				   XFS_BMDR_SPACE_CALC(MINABTPTRS);
614 		break;
615 	case 512:
616 	case 1024:
617 	case 2048:
618 		mp->m_attroffset = XFS_BMDR_SPACE_CALC(6 * MINABTPTRS);
619 		break;
620 	default:
621 		ASSERT(0);
622 	}
623 	ASSERT(mp->m_attroffset < XFS_LITINO(mp));
624 
625 	for (i = 0; i < 2; i++) {
626 		mp->m_alloc_mxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
627 			xfs_alloc, i == 0);
628 		mp->m_alloc_mnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
629 			xfs_alloc, i == 0);
630 	}
631 	for (i = 0; i < 2; i++) {
632 		mp->m_bmap_dmxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
633 			xfs_bmbt, i == 0);
634 		mp->m_bmap_dmnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
635 			xfs_bmbt, i == 0);
636 	}
637 	for (i = 0; i < 2; i++) {
638 		mp->m_inobt_mxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
639 			xfs_inobt, i == 0);
640 		mp->m_inobt_mnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
641 			xfs_inobt, i == 0);
642 	}
643 
644 	mp->m_bsize = XFS_FSB_TO_BB(mp, 1);
645 	mp->m_ialloc_inos = (int)MAX((__uint16_t)XFS_INODES_PER_CHUNK,
646 					sbp->sb_inopblock);
647 	mp->m_ialloc_blks = mp->m_ialloc_inos >> sbp->sb_inopblog;
648 }
649 /*
650  * xfs_mountfs
651  *
652  * This function does the following on an initial mount of a file system:
653  *	- reads the superblock from disk and init the mount struct
654  *	- if we're a 32-bit kernel, do a size check on the superblock
655  *		so we don't mount terabyte filesystems
656  *	- init mount struct realtime fields
657  *	- allocate inode hash table for fs
658  *	- init directory manager
659  *	- perform recovery and init the log manager
660  */
661 int
662 xfs_mountfs(
663 	vfs_t		*vfsp,
664 	xfs_mount_t	*mp,
665 	int		mfsi_flags)
666 {
667 	xfs_buf_t	*bp;
668 	xfs_sb_t	*sbp = &(mp->m_sb);
669 	xfs_inode_t	*rip;
670 	vnode_t		*rvp = NULL;
671 	int		readio_log, writeio_log;
672 	xfs_daddr_t	d;
673 	__uint64_t	ret64;
674 	__int64_t	update_flags;
675 	uint		quotamount, quotaflags;
676 	int		agno;
677 	int		uuid_mounted = 0;
678 	int		error = 0;
679 
680 	if (mp->m_sb_bp == NULL) {
681 		if ((error = xfs_readsb(mp))) {
682 			return error;
683 		}
684 	}
685 	xfs_mount_common(mp, sbp);
686 
687 	/*
688 	 * Check if sb_agblocks is aligned at stripe boundary
689 	 * If sb_agblocks is NOT aligned turn off m_dalign since
690 	 * allocator alignment is within an ag, therefore ag has
691 	 * to be aligned at stripe boundary.
692 	 */
693 	update_flags = 0LL;
694 	if (mp->m_dalign && !(mfsi_flags & XFS_MFSI_SECOND)) {
695 		/*
696 		 * If stripe unit and stripe width are not multiples
697 		 * of the fs blocksize turn off alignment.
698 		 */
699 		if ((BBTOB(mp->m_dalign) & mp->m_blockmask) ||
700 		    (BBTOB(mp->m_swidth) & mp->m_blockmask)) {
701 			if (mp->m_flags & XFS_MOUNT_RETERR) {
702 				cmn_err(CE_WARN,
703 					"XFS: alignment check 1 failed");
704 				error = XFS_ERROR(EINVAL);
705 				goto error1;
706 			}
707 			mp->m_dalign = mp->m_swidth = 0;
708 		} else {
709 			/*
710 			 * Convert the stripe unit and width to FSBs.
711 			 */
712 			mp->m_dalign = XFS_BB_TO_FSBT(mp, mp->m_dalign);
713 			if (mp->m_dalign && (sbp->sb_agblocks % mp->m_dalign)) {
714 				if (mp->m_flags & XFS_MOUNT_RETERR) {
715 					error = XFS_ERROR(EINVAL);
716 					goto error1;
717 				}
718 				xfs_fs_cmn_err(CE_WARN, mp,
719 "stripe alignment turned off: sunit(%d)/swidth(%d) incompatible with agsize(%d)",
720 					mp->m_dalign, mp->m_swidth,
721 					sbp->sb_agblocks);
722 
723 				mp->m_dalign = 0;
724 				mp->m_swidth = 0;
725 			} else if (mp->m_dalign) {
726 				mp->m_swidth = XFS_BB_TO_FSBT(mp, mp->m_swidth);
727 			} else {
728 				if (mp->m_flags & XFS_MOUNT_RETERR) {
729 					xfs_fs_cmn_err(CE_WARN, mp,
730 "stripe alignment turned off: sunit(%d) less than bsize(%d)",
731                                         	mp->m_dalign,
732 						mp->m_blockmask +1);
733 					error = XFS_ERROR(EINVAL);
734 					goto error1;
735 				}
736 				mp->m_swidth = 0;
737 			}
738 		}
739 
740 		/*
741 		 * Update superblock with new values
742 		 * and log changes
743 		 */
744 		if (XFS_SB_VERSION_HASDALIGN(sbp)) {
745 			if (sbp->sb_unit != mp->m_dalign) {
746 				sbp->sb_unit = mp->m_dalign;
747 				update_flags |= XFS_SB_UNIT;
748 			}
749 			if (sbp->sb_width != mp->m_swidth) {
750 				sbp->sb_width = mp->m_swidth;
751 				update_flags |= XFS_SB_WIDTH;
752 			}
753 		}
754 	} else if ((mp->m_flags & XFS_MOUNT_NOALIGN) != XFS_MOUNT_NOALIGN &&
755 		    XFS_SB_VERSION_HASDALIGN(&mp->m_sb)) {
756 			mp->m_dalign = sbp->sb_unit;
757 			mp->m_swidth = sbp->sb_width;
758 	}
759 
760 	xfs_alloc_compute_maxlevels(mp);
761 	xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK);
762 	xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK);
763 	xfs_ialloc_compute_maxlevels(mp);
764 
765 	if (sbp->sb_imax_pct) {
766 		__uint64_t	icount;
767 
768 		/* Make sure the maximum inode count is a multiple of the
769 		 * units we allocate inodes in.
770 		 */
771 
772 		icount = sbp->sb_dblocks * sbp->sb_imax_pct;
773 		do_div(icount, 100);
774 		do_div(icount, mp->m_ialloc_blks);
775 		mp->m_maxicount = (icount * mp->m_ialloc_blks)  <<
776 				   sbp->sb_inopblog;
777 	} else
778 		mp->m_maxicount = 0;
779 
780 	mp->m_maxioffset = xfs_max_file_offset(sbp->sb_blocklog);
781 
782 	/*
783 	 * XFS uses the uuid from the superblock as the unique
784 	 * identifier for fsid.  We can not use the uuid from the volume
785 	 * since a single partition filesystem is identical to a single
786 	 * partition volume/filesystem.
787 	 */
788 	if ((mfsi_flags & XFS_MFSI_SECOND) == 0 &&
789 	    (mp->m_flags & XFS_MOUNT_NOUUID) == 0) {
790 		if (xfs_uuid_mount(mp)) {
791 			error = XFS_ERROR(EINVAL);
792 			goto error1;
793 		}
794 		uuid_mounted=1;
795 		ret64 = uuid_hash64(&sbp->sb_uuid);
796 		memcpy(&vfsp->vfs_fsid, &ret64, sizeof(ret64));
797 	}
798 
799 	/*
800 	 * Set the default minimum read and write sizes unless
801 	 * already specified in a mount option.
802 	 * We use smaller I/O sizes when the file system
803 	 * is being used for NFS service (wsync mount option).
804 	 */
805 	if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
806 		if (mp->m_flags & XFS_MOUNT_WSYNC) {
807 			readio_log = XFS_WSYNC_READIO_LOG;
808 			writeio_log = XFS_WSYNC_WRITEIO_LOG;
809 		} else {
810 			readio_log = XFS_READIO_LOG_LARGE;
811 			writeio_log = XFS_WRITEIO_LOG_LARGE;
812 		}
813 	} else {
814 		readio_log = mp->m_readio_log;
815 		writeio_log = mp->m_writeio_log;
816 	}
817 
818 	/*
819 	 * Set the number of readahead buffers to use based on
820 	 * physical memory size.
821 	 */
822 	if (xfs_physmem <= 4096)		/* <= 16MB */
823 		mp->m_nreadaheads = XFS_RW_NREADAHEAD_16MB;
824 	else if (xfs_physmem <= 8192)	/* <= 32MB */
825 		mp->m_nreadaheads = XFS_RW_NREADAHEAD_32MB;
826 	else
827 		mp->m_nreadaheads = XFS_RW_NREADAHEAD_K32;
828 	if (sbp->sb_blocklog > readio_log) {
829 		mp->m_readio_log = sbp->sb_blocklog;
830 	} else {
831 		mp->m_readio_log = readio_log;
832 	}
833 	mp->m_readio_blocks = 1 << (mp->m_readio_log - sbp->sb_blocklog);
834 	if (sbp->sb_blocklog > writeio_log) {
835 		mp->m_writeio_log = sbp->sb_blocklog;
836 	} else {
837 		mp->m_writeio_log = writeio_log;
838 	}
839 	mp->m_writeio_blocks = 1 << (mp->m_writeio_log - sbp->sb_blocklog);
840 
841 	/*
842 	 * Set the inode cluster size based on the physical memory
843 	 * size.  This may still be overridden by the file system
844 	 * block size if it is larger than the chosen cluster size.
845 	 */
846 	if (xfs_physmem <= btoc(32 * 1024 * 1024)) { /* <= 32 MB */
847 		mp->m_inode_cluster_size = XFS_INODE_SMALL_CLUSTER_SIZE;
848 	} else {
849 		mp->m_inode_cluster_size = XFS_INODE_BIG_CLUSTER_SIZE;
850 	}
851 	/*
852 	 * Set whether we're using inode alignment.
853 	 */
854 	if (XFS_SB_VERSION_HASALIGN(&mp->m_sb) &&
855 	    mp->m_sb.sb_inoalignmt >=
856 	    XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size))
857 		mp->m_inoalign_mask = mp->m_sb.sb_inoalignmt - 1;
858 	else
859 		mp->m_inoalign_mask = 0;
860 	/*
861 	 * If we are using stripe alignment, check whether
862 	 * the stripe unit is a multiple of the inode alignment
863 	 */
864 	if (mp->m_dalign && mp->m_inoalign_mask &&
865 	    !(mp->m_dalign & mp->m_inoalign_mask))
866 		mp->m_sinoalign = mp->m_dalign;
867 	else
868 		mp->m_sinoalign = 0;
869 	/*
870 	 * Check that the data (and log if separate) are an ok size.
871 	 */
872 	d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
873 	if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
874 		cmn_err(CE_WARN, "XFS: size check 1 failed");
875 		error = XFS_ERROR(E2BIG);
876 		goto error1;
877 	}
878 	error = xfs_read_buf(mp, mp->m_ddev_targp,
879 			     d - XFS_FSS_TO_BB(mp, 1),
880 			     XFS_FSS_TO_BB(mp, 1), 0, &bp);
881 	if (!error) {
882 		xfs_buf_relse(bp);
883 	} else {
884 		cmn_err(CE_WARN, "XFS: size check 2 failed");
885 		if (error == ENOSPC) {
886 			error = XFS_ERROR(E2BIG);
887 		}
888 		goto error1;
889 	}
890 
891 	if (((mfsi_flags & XFS_MFSI_CLIENT) == 0) &&
892 	    mp->m_logdev_targp != mp->m_ddev_targp) {
893 		d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
894 		if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
895 			cmn_err(CE_WARN, "XFS: size check 3 failed");
896 			error = XFS_ERROR(E2BIG);
897 			goto error1;
898 		}
899 		error = xfs_read_buf(mp, mp->m_logdev_targp,
900 				     d - XFS_FSB_TO_BB(mp, 1),
901 				     XFS_FSB_TO_BB(mp, 1), 0, &bp);
902 		if (!error) {
903 			xfs_buf_relse(bp);
904 		} else {
905 			cmn_err(CE_WARN, "XFS: size check 3 failed");
906 			if (error == ENOSPC) {
907 				error = XFS_ERROR(E2BIG);
908 			}
909 			goto error1;
910 		}
911 	}
912 
913 	/*
914 	 * Initialize realtime fields in the mount structure
915 	 */
916 	if ((error = xfs_rtmount_init(mp))) {
917 		cmn_err(CE_WARN, "XFS: RT mount failed");
918 		goto error1;
919 	}
920 
921 	/*
922 	 * For client case we are done now
923 	 */
924 	if (mfsi_flags & XFS_MFSI_CLIENT) {
925 		return 0;
926 	}
927 
928 	/*
929 	 *  Copies the low order bits of the timestamp and the randomly
930 	 *  set "sequence" number out of a UUID.
931 	 */
932 	uuid_getnodeuniq(&sbp->sb_uuid, mp->m_fixedfsid);
933 
934 	/*
935 	 *  The vfs structure needs to have a file system independent
936 	 *  way of checking for the invariant file system ID.  Since it
937 	 *  can't look at mount structures it has a pointer to the data
938 	 *  in the mount structure.
939 	 *
940 	 *  File systems that don't support user level file handles (i.e.
941 	 *  all of them except for XFS) will leave vfs_altfsid as NULL.
942 	 */
943 	vfsp->vfs_altfsid = (xfs_fsid_t *)mp->m_fixedfsid;
944 	mp->m_dmevmask = 0;	/* not persistent; set after each mount */
945 
946 	/*
947 	 * Select the right directory manager.
948 	 */
949 	mp->m_dirops =
950 		XFS_SB_VERSION_HASDIRV2(&mp->m_sb) ?
951 			xfsv2_dirops :
952 			xfsv1_dirops;
953 
954 	/*
955 	 * Initialize directory manager's entries.
956 	 */
957 	XFS_DIR_MOUNT(mp);
958 
959 	/*
960 	 * Initialize the attribute manager's entries.
961 	 */
962 	mp->m_attr_magicpct = (mp->m_sb.sb_blocksize * 37) / 100;
963 
964 	/*
965 	 * Initialize the precomputed transaction reservations values.
966 	 */
967 	xfs_trans_init(mp);
968 
969 	/*
970 	 * Allocate and initialize the inode hash table for this
971 	 * file system.
972 	 */
973 	xfs_ihash_init(mp);
974 	xfs_chash_init(mp);
975 
976 	/*
977 	 * Allocate and initialize the per-ag data.
978 	 */
979 	init_rwsem(&mp->m_peraglock);
980 	mp->m_perag =
981 		kmem_zalloc(sbp->sb_agcount * sizeof(xfs_perag_t), KM_SLEEP);
982 
983 	mp->m_maxagi = xfs_initialize_perag(vfsp, mp, sbp->sb_agcount);
984 
985 	/*
986 	 * log's mount-time initialization. Perform 1st part recovery if needed
987 	 */
988 	if (likely(sbp->sb_logblocks > 0)) {	/* check for volume case */
989 		error = xfs_log_mount(mp, mp->m_logdev_targp,
990 				      XFS_FSB_TO_DADDR(mp, sbp->sb_logstart),
991 				      XFS_FSB_TO_BB(mp, sbp->sb_logblocks));
992 		if (error) {
993 			cmn_err(CE_WARN, "XFS: log mount failed");
994 			goto error2;
995 		}
996 	} else {	/* No log has been defined */
997 		cmn_err(CE_WARN, "XFS: no log defined");
998 		XFS_ERROR_REPORT("xfs_mountfs_int(1)", XFS_ERRLEVEL_LOW, mp);
999 		error = XFS_ERROR(EFSCORRUPTED);
1000 		goto error2;
1001 	}
1002 
1003 	/*
1004 	 * Get and sanity-check the root inode.
1005 	 * Save the pointer to it in the mount structure.
1006 	 */
1007 	error = xfs_iget(mp, NULL, sbp->sb_rootino, 0, XFS_ILOCK_EXCL, &rip, 0);
1008 	if (error) {
1009 		cmn_err(CE_WARN, "XFS: failed to read root inode");
1010 		goto error3;
1011 	}
1012 
1013 	ASSERT(rip != NULL);
1014 	rvp = XFS_ITOV(rip);
1015 
1016 	if (unlikely((rip->i_d.di_mode & S_IFMT) != S_IFDIR)) {
1017 		cmn_err(CE_WARN, "XFS: corrupted root inode");
1018 		prdev("Root inode %llu is not a directory",
1019 		      mp->m_ddev_targp, (unsigned long long)rip->i_ino);
1020 		xfs_iunlock(rip, XFS_ILOCK_EXCL);
1021 		XFS_ERROR_REPORT("xfs_mountfs_int(2)", XFS_ERRLEVEL_LOW,
1022 				 mp);
1023 		error = XFS_ERROR(EFSCORRUPTED);
1024 		goto error4;
1025 	}
1026 	mp->m_rootip = rip;	/* save it */
1027 
1028 	xfs_iunlock(rip, XFS_ILOCK_EXCL);
1029 
1030 	/*
1031 	 * Initialize realtime inode pointers in the mount structure
1032 	 */
1033 	if ((error = xfs_rtmount_inodes(mp))) {
1034 		/*
1035 		 * Free up the root inode.
1036 		 */
1037 		cmn_err(CE_WARN, "XFS: failed to read RT inodes");
1038 		goto error4;
1039 	}
1040 
1041 	/*
1042 	 * If fs is not mounted readonly, then update the superblock
1043 	 * unit and width changes.
1044 	 */
1045 	if (update_flags && !(vfsp->vfs_flag & VFS_RDONLY))
1046 		xfs_mount_log_sbunit(mp, update_flags);
1047 
1048 	/*
1049 	 * Initialise the XFS quota management subsystem for this mount
1050 	 */
1051 	if ((error = XFS_QM_INIT(mp, &quotamount, &quotaflags)))
1052 		goto error4;
1053 
1054 	/*
1055 	 * Finish recovering the file system.  This part needed to be
1056 	 * delayed until after the root and real-time bitmap inodes
1057 	 * were consistently read in.
1058 	 */
1059 	error = xfs_log_mount_finish(mp, mfsi_flags);
1060 	if (error) {
1061 		cmn_err(CE_WARN, "XFS: log mount finish failed");
1062 		goto error4;
1063 	}
1064 
1065 	/*
1066 	 * Complete the quota initialisation, post-log-replay component.
1067 	 */
1068 	if ((error = XFS_QM_MOUNT(mp, quotamount, quotaflags, mfsi_flags)))
1069 		goto error4;
1070 
1071 	return 0;
1072 
1073  error4:
1074 	/*
1075 	 * Free up the root inode.
1076 	 */
1077 	VN_RELE(rvp);
1078  error3:
1079 	xfs_log_unmount_dealloc(mp);
1080  error2:
1081 	xfs_ihash_free(mp);
1082 	xfs_chash_free(mp);
1083 	for (agno = 0; agno < sbp->sb_agcount; agno++)
1084 		if (mp->m_perag[agno].pagb_list)
1085 			kmem_free(mp->m_perag[agno].pagb_list,
1086 			  sizeof(xfs_perag_busy_t) * XFS_PAGB_NUM_SLOTS);
1087 	kmem_free(mp->m_perag, sbp->sb_agcount * sizeof(xfs_perag_t));
1088 	mp->m_perag = NULL;
1089 	/* FALLTHROUGH */
1090  error1:
1091 	if (uuid_mounted)
1092 		xfs_uuid_unmount(mp);
1093 	xfs_freesb(mp);
1094 	return error;
1095 }
1096 
1097 /*
1098  * xfs_unmountfs
1099  *
1100  * This flushes out the inodes,dquots and the superblock, unmounts the
1101  * log and makes sure that incore structures are freed.
1102  */
1103 int
1104 xfs_unmountfs(xfs_mount_t *mp, struct cred *cr)
1105 {
1106 	struct vfs	*vfsp = XFS_MTOVFS(mp);
1107 #if defined(DEBUG) || defined(INDUCE_IO_ERROR)
1108 	int64_t		fsid;
1109 #endif
1110 
1111 	xfs_iflush_all(mp);
1112 
1113 	XFS_QM_DQPURGEALL(mp, XFS_QMOPT_QUOTALL | XFS_QMOPT_UMOUNTING);
1114 
1115 	/*
1116 	 * Flush out the log synchronously so that we know for sure
1117 	 * that nothing is pinned.  This is important because bflush()
1118 	 * will skip pinned buffers.
1119 	 */
1120 	xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE | XFS_LOG_SYNC);
1121 
1122 	xfs_binval(mp->m_ddev_targp);
1123 	if (mp->m_rtdev_targp) {
1124 		xfs_binval(mp->m_rtdev_targp);
1125 	}
1126 
1127 	xfs_unmountfs_writesb(mp);
1128 
1129 	xfs_unmountfs_wait(mp); 		/* wait for async bufs */
1130 
1131 	xfs_log_unmount(mp);			/* Done! No more fs ops. */
1132 
1133 	xfs_freesb(mp);
1134 
1135 	/*
1136 	 * All inodes from this mount point should be freed.
1137 	 */
1138 	ASSERT(mp->m_inodes == NULL);
1139 
1140 	xfs_unmountfs_close(mp, cr);
1141 	if ((mp->m_flags & XFS_MOUNT_NOUUID) == 0)
1142 		xfs_uuid_unmount(mp);
1143 
1144 #if defined(DEBUG) || defined(INDUCE_IO_ERROR)
1145 	/*
1146 	 * clear all error tags on this filesystem
1147 	 */
1148 	memcpy(&fsid, &vfsp->vfs_fsid, sizeof(int64_t));
1149 	xfs_errortag_clearall_umount(fsid, mp->m_fsname, 0);
1150 #endif
1151 	XFS_IODONE(vfsp);
1152 	xfs_mount_free(mp, 1);
1153 	return 0;
1154 }
1155 
1156 void
1157 xfs_unmountfs_close(xfs_mount_t *mp, struct cred *cr)
1158 {
1159 	if (mp->m_logdev_targp != mp->m_ddev_targp)
1160 		xfs_free_buftarg(mp->m_logdev_targp, 1);
1161 	if (mp->m_rtdev_targp)
1162 		xfs_free_buftarg(mp->m_rtdev_targp, 1);
1163 	xfs_free_buftarg(mp->m_ddev_targp, 0);
1164 }
1165 
1166 STATIC void
1167 xfs_unmountfs_wait(xfs_mount_t *mp)
1168 {
1169 	if (mp->m_logdev_targp != mp->m_ddev_targp)
1170 		xfs_wait_buftarg(mp->m_logdev_targp);
1171 	if (mp->m_rtdev_targp)
1172 		xfs_wait_buftarg(mp->m_rtdev_targp);
1173 	xfs_wait_buftarg(mp->m_ddev_targp);
1174 }
1175 
1176 int
1177 xfs_unmountfs_writesb(xfs_mount_t *mp)
1178 {
1179 	xfs_buf_t	*sbp;
1180 	xfs_sb_t	*sb;
1181 	int		error = 0;
1182 
1183 	/*
1184 	 * skip superblock write if fs is read-only, or
1185 	 * if we are doing a forced umount.
1186 	 */
1187 	sbp = xfs_getsb(mp, 0);
1188 	if (!(XFS_MTOVFS(mp)->vfs_flag & VFS_RDONLY ||
1189 		XFS_FORCED_SHUTDOWN(mp))) {
1190 
1191 		xfs_icsb_sync_counters(mp);
1192 
1193 		/*
1194 		 * mark shared-readonly if desired
1195 		 */
1196 		sb = XFS_BUF_TO_SBP(sbp);
1197 		if (mp->m_mk_sharedro) {
1198 			if (!(sb->sb_flags & XFS_SBF_READONLY))
1199 				sb->sb_flags |= XFS_SBF_READONLY;
1200 			if (!XFS_SB_VERSION_HASSHARED(sb))
1201 				XFS_SB_VERSION_ADDSHARED(sb);
1202 			xfs_fs_cmn_err(CE_NOTE, mp,
1203 				"Unmounting, marking shared read-only");
1204 		}
1205 		XFS_BUF_UNDONE(sbp);
1206 		XFS_BUF_UNREAD(sbp);
1207 		XFS_BUF_UNDELAYWRITE(sbp);
1208 		XFS_BUF_WRITE(sbp);
1209 		XFS_BUF_UNASYNC(sbp);
1210 		ASSERT(XFS_BUF_TARGET(sbp) == mp->m_ddev_targp);
1211 		xfsbdstrat(mp, sbp);
1212 		/* Nevermind errors we might get here. */
1213 		error = xfs_iowait(sbp);
1214 		if (error)
1215 			xfs_ioerror_alert("xfs_unmountfs_writesb",
1216 					  mp, sbp, XFS_BUF_ADDR(sbp));
1217 		if (error && mp->m_mk_sharedro)
1218 			xfs_fs_cmn_err(CE_ALERT, mp, "Superblock write error detected while unmounting.  Filesystem may not be marked shared readonly");
1219 	}
1220 	xfs_buf_relse(sbp);
1221 	return error;
1222 }
1223 
1224 /*
1225  * xfs_mod_sb() can be used to copy arbitrary changes to the
1226  * in-core superblock into the superblock buffer to be logged.
1227  * It does not provide the higher level of locking that is
1228  * needed to protect the in-core superblock from concurrent
1229  * access.
1230  */
1231 void
1232 xfs_mod_sb(xfs_trans_t *tp, __int64_t fields)
1233 {
1234 	xfs_buf_t	*bp;
1235 	int		first;
1236 	int		last;
1237 	xfs_mount_t	*mp;
1238 	xfs_sb_t	*sbp;
1239 	xfs_sb_field_t	f;
1240 
1241 	ASSERT(fields);
1242 	if (!fields)
1243 		return;
1244 	mp = tp->t_mountp;
1245 	bp = xfs_trans_getsb(tp, mp, 0);
1246 	sbp = XFS_BUF_TO_SBP(bp);
1247 	first = sizeof(xfs_sb_t);
1248 	last = 0;
1249 
1250 	/* translate/copy */
1251 
1252 	xfs_xlatesb(XFS_BUF_PTR(bp), &(mp->m_sb), -1, fields);
1253 
1254 	/* find modified range */
1255 
1256 	f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
1257 	ASSERT((1LL << f) & XFS_SB_MOD_BITS);
1258 	first = xfs_sb_info[f].offset;
1259 
1260 	f = (xfs_sb_field_t)xfs_highbit64((__uint64_t)fields);
1261 	ASSERT((1LL << f) & XFS_SB_MOD_BITS);
1262 	last = xfs_sb_info[f + 1].offset - 1;
1263 
1264 	xfs_trans_log_buf(tp, bp, first, last);
1265 }
1266 /*
1267  * xfs_mod_incore_sb_unlocked() is a utility routine common used to apply
1268  * a delta to a specified field in the in-core superblock.  Simply
1269  * switch on the field indicated and apply the delta to that field.
1270  * Fields are not allowed to dip below zero, so if the delta would
1271  * do this do not apply it and return EINVAL.
1272  *
1273  * The SB_LOCK must be held when this routine is called.
1274  */
1275 int
1276 xfs_mod_incore_sb_unlocked(xfs_mount_t *mp, xfs_sb_field_t field,
1277 			int delta, int rsvd)
1278 {
1279 	int		scounter;	/* short counter for 32 bit fields */
1280 	long long	lcounter;	/* long counter for 64 bit fields */
1281 	long long	res_used, rem;
1282 
1283 	/*
1284 	 * With the in-core superblock spin lock held, switch
1285 	 * on the indicated field.  Apply the delta to the
1286 	 * proper field.  If the fields value would dip below
1287 	 * 0, then do not apply the delta and return EINVAL.
1288 	 */
1289 	switch (field) {
1290 	case XFS_SBS_ICOUNT:
1291 		lcounter = (long long)mp->m_sb.sb_icount;
1292 		lcounter += delta;
1293 		if (lcounter < 0) {
1294 			ASSERT(0);
1295 			return XFS_ERROR(EINVAL);
1296 		}
1297 		mp->m_sb.sb_icount = lcounter;
1298 		return 0;
1299 	case XFS_SBS_IFREE:
1300 		lcounter = (long long)mp->m_sb.sb_ifree;
1301 		lcounter += delta;
1302 		if (lcounter < 0) {
1303 			ASSERT(0);
1304 			return XFS_ERROR(EINVAL);
1305 		}
1306 		mp->m_sb.sb_ifree = lcounter;
1307 		return 0;
1308 	case XFS_SBS_FDBLOCKS:
1309 
1310 		lcounter = (long long)mp->m_sb.sb_fdblocks;
1311 		res_used = (long long)(mp->m_resblks - mp->m_resblks_avail);
1312 
1313 		if (delta > 0) {		/* Putting blocks back */
1314 			if (res_used > delta) {
1315 				mp->m_resblks_avail += delta;
1316 			} else {
1317 				rem = delta - res_used;
1318 				mp->m_resblks_avail = mp->m_resblks;
1319 				lcounter += rem;
1320 			}
1321 		} else {				/* Taking blocks away */
1322 
1323 			lcounter += delta;
1324 
1325 		/*
1326 		 * If were out of blocks, use any available reserved blocks if
1327 		 * were allowed to.
1328 		 */
1329 
1330 			if (lcounter < 0) {
1331 				if (rsvd) {
1332 					lcounter = (long long)mp->m_resblks_avail + delta;
1333 					if (lcounter < 0) {
1334 						return XFS_ERROR(ENOSPC);
1335 					}
1336 					mp->m_resblks_avail = lcounter;
1337 					return 0;
1338 				} else {	/* not reserved */
1339 					return XFS_ERROR(ENOSPC);
1340 				}
1341 			}
1342 		}
1343 
1344 		mp->m_sb.sb_fdblocks = lcounter;
1345 		return 0;
1346 	case XFS_SBS_FREXTENTS:
1347 		lcounter = (long long)mp->m_sb.sb_frextents;
1348 		lcounter += delta;
1349 		if (lcounter < 0) {
1350 			return XFS_ERROR(ENOSPC);
1351 		}
1352 		mp->m_sb.sb_frextents = lcounter;
1353 		return 0;
1354 	case XFS_SBS_DBLOCKS:
1355 		lcounter = (long long)mp->m_sb.sb_dblocks;
1356 		lcounter += delta;
1357 		if (lcounter < 0) {
1358 			ASSERT(0);
1359 			return XFS_ERROR(EINVAL);
1360 		}
1361 		mp->m_sb.sb_dblocks = lcounter;
1362 		return 0;
1363 	case XFS_SBS_AGCOUNT:
1364 		scounter = mp->m_sb.sb_agcount;
1365 		scounter += delta;
1366 		if (scounter < 0) {
1367 			ASSERT(0);
1368 			return XFS_ERROR(EINVAL);
1369 		}
1370 		mp->m_sb.sb_agcount = scounter;
1371 		return 0;
1372 	case XFS_SBS_IMAX_PCT:
1373 		scounter = mp->m_sb.sb_imax_pct;
1374 		scounter += delta;
1375 		if (scounter < 0) {
1376 			ASSERT(0);
1377 			return XFS_ERROR(EINVAL);
1378 		}
1379 		mp->m_sb.sb_imax_pct = scounter;
1380 		return 0;
1381 	case XFS_SBS_REXTSIZE:
1382 		scounter = mp->m_sb.sb_rextsize;
1383 		scounter += delta;
1384 		if (scounter < 0) {
1385 			ASSERT(0);
1386 			return XFS_ERROR(EINVAL);
1387 		}
1388 		mp->m_sb.sb_rextsize = scounter;
1389 		return 0;
1390 	case XFS_SBS_RBMBLOCKS:
1391 		scounter = mp->m_sb.sb_rbmblocks;
1392 		scounter += delta;
1393 		if (scounter < 0) {
1394 			ASSERT(0);
1395 			return XFS_ERROR(EINVAL);
1396 		}
1397 		mp->m_sb.sb_rbmblocks = scounter;
1398 		return 0;
1399 	case XFS_SBS_RBLOCKS:
1400 		lcounter = (long long)mp->m_sb.sb_rblocks;
1401 		lcounter += delta;
1402 		if (lcounter < 0) {
1403 			ASSERT(0);
1404 			return XFS_ERROR(EINVAL);
1405 		}
1406 		mp->m_sb.sb_rblocks = lcounter;
1407 		return 0;
1408 	case XFS_SBS_REXTENTS:
1409 		lcounter = (long long)mp->m_sb.sb_rextents;
1410 		lcounter += delta;
1411 		if (lcounter < 0) {
1412 			ASSERT(0);
1413 			return XFS_ERROR(EINVAL);
1414 		}
1415 		mp->m_sb.sb_rextents = lcounter;
1416 		return 0;
1417 	case XFS_SBS_REXTSLOG:
1418 		scounter = mp->m_sb.sb_rextslog;
1419 		scounter += delta;
1420 		if (scounter < 0) {
1421 			ASSERT(0);
1422 			return XFS_ERROR(EINVAL);
1423 		}
1424 		mp->m_sb.sb_rextslog = scounter;
1425 		return 0;
1426 	default:
1427 		ASSERT(0);
1428 		return XFS_ERROR(EINVAL);
1429 	}
1430 }
1431 
1432 /*
1433  * xfs_mod_incore_sb() is used to change a field in the in-core
1434  * superblock structure by the specified delta.  This modification
1435  * is protected by the SB_LOCK.  Just use the xfs_mod_incore_sb_unlocked()
1436  * routine to do the work.
1437  */
1438 int
1439 xfs_mod_incore_sb(xfs_mount_t *mp, xfs_sb_field_t field, int delta, int rsvd)
1440 {
1441 	unsigned long	s;
1442 	int	status;
1443 
1444 	/* check for per-cpu counters */
1445 	switch (field) {
1446 #ifdef HAVE_PERCPU_SB
1447 	case XFS_SBS_ICOUNT:
1448 	case XFS_SBS_IFREE:
1449 	case XFS_SBS_FDBLOCKS:
1450 		if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1451 			status = xfs_icsb_modify_counters(mp, field,
1452 							delta, rsvd);
1453 			break;
1454 		}
1455 		/* FALLTHROUGH */
1456 #endif
1457 	default:
1458 		s = XFS_SB_LOCK(mp);
1459 		status = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
1460 		XFS_SB_UNLOCK(mp, s);
1461 		break;
1462 	}
1463 
1464 	return status;
1465 }
1466 
1467 /*
1468  * xfs_mod_incore_sb_batch() is used to change more than one field
1469  * in the in-core superblock structure at a time.  This modification
1470  * is protected by a lock internal to this module.  The fields and
1471  * changes to those fields are specified in the array of xfs_mod_sb
1472  * structures passed in.
1473  *
1474  * Either all of the specified deltas will be applied or none of
1475  * them will.  If any modified field dips below 0, then all modifications
1476  * will be backed out and EINVAL will be returned.
1477  */
1478 int
1479 xfs_mod_incore_sb_batch(xfs_mount_t *mp, xfs_mod_sb_t *msb, uint nmsb, int rsvd)
1480 {
1481 	unsigned long	s;
1482 	int		status=0;
1483 	xfs_mod_sb_t	*msbp;
1484 
1485 	/*
1486 	 * Loop through the array of mod structures and apply each
1487 	 * individually.  If any fail, then back out all those
1488 	 * which have already been applied.  Do all of this within
1489 	 * the scope of the SB_LOCK so that all of the changes will
1490 	 * be atomic.
1491 	 */
1492 	s = XFS_SB_LOCK(mp);
1493 	msbp = &msb[0];
1494 	for (msbp = &msbp[0]; msbp < (msb + nmsb); msbp++) {
1495 		/*
1496 		 * Apply the delta at index n.  If it fails, break
1497 		 * from the loop so we'll fall into the undo loop
1498 		 * below.
1499 		 */
1500 		switch (msbp->msb_field) {
1501 #ifdef HAVE_PERCPU_SB
1502 		case XFS_SBS_ICOUNT:
1503 		case XFS_SBS_IFREE:
1504 		case XFS_SBS_FDBLOCKS:
1505 			if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1506 				status = xfs_icsb_modify_counters_locked(mp,
1507 							msbp->msb_field,
1508 							msbp->msb_delta, rsvd);
1509 				break;
1510 			}
1511 			/* FALLTHROUGH */
1512 #endif
1513 		default:
1514 			status = xfs_mod_incore_sb_unlocked(mp,
1515 						msbp->msb_field,
1516 						msbp->msb_delta, rsvd);
1517 			break;
1518 		}
1519 
1520 		if (status != 0) {
1521 			break;
1522 		}
1523 	}
1524 
1525 	/*
1526 	 * If we didn't complete the loop above, then back out
1527 	 * any changes made to the superblock.  If you add code
1528 	 * between the loop above and here, make sure that you
1529 	 * preserve the value of status. Loop back until
1530 	 * we step below the beginning of the array.  Make sure
1531 	 * we don't touch anything back there.
1532 	 */
1533 	if (status != 0) {
1534 		msbp--;
1535 		while (msbp >= msb) {
1536 			switch (msbp->msb_field) {
1537 #ifdef HAVE_PERCPU_SB
1538 			case XFS_SBS_ICOUNT:
1539 			case XFS_SBS_IFREE:
1540 			case XFS_SBS_FDBLOCKS:
1541 				if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1542 					status =
1543 					    xfs_icsb_modify_counters_locked(mp,
1544 							msbp->msb_field,
1545 							-(msbp->msb_delta),
1546 							rsvd);
1547 					break;
1548 				}
1549 				/* FALLTHROUGH */
1550 #endif
1551 			default:
1552 				status = xfs_mod_incore_sb_unlocked(mp,
1553 							msbp->msb_field,
1554 							-(msbp->msb_delta),
1555 							rsvd);
1556 				break;
1557 			}
1558 			ASSERT(status == 0);
1559 			msbp--;
1560 		}
1561 	}
1562 	XFS_SB_UNLOCK(mp, s);
1563 	return status;
1564 }
1565 
1566 /*
1567  * xfs_getsb() is called to obtain the buffer for the superblock.
1568  * The buffer is returned locked and read in from disk.
1569  * The buffer should be released with a call to xfs_brelse().
1570  *
1571  * If the flags parameter is BUF_TRYLOCK, then we'll only return
1572  * the superblock buffer if it can be locked without sleeping.
1573  * If it can't then we'll return NULL.
1574  */
1575 xfs_buf_t *
1576 xfs_getsb(
1577 	xfs_mount_t	*mp,
1578 	int		flags)
1579 {
1580 	xfs_buf_t	*bp;
1581 
1582 	ASSERT(mp->m_sb_bp != NULL);
1583 	bp = mp->m_sb_bp;
1584 	if (flags & XFS_BUF_TRYLOCK) {
1585 		if (!XFS_BUF_CPSEMA(bp)) {
1586 			return NULL;
1587 		}
1588 	} else {
1589 		XFS_BUF_PSEMA(bp, PRIBIO);
1590 	}
1591 	XFS_BUF_HOLD(bp);
1592 	ASSERT(XFS_BUF_ISDONE(bp));
1593 	return bp;
1594 }
1595 
1596 /*
1597  * Used to free the superblock along various error paths.
1598  */
1599 void
1600 xfs_freesb(
1601 	xfs_mount_t	*mp)
1602 {
1603 	xfs_buf_t	*bp;
1604 
1605 	/*
1606 	 * Use xfs_getsb() so that the buffer will be locked
1607 	 * when we call xfs_buf_relse().
1608 	 */
1609 	bp = xfs_getsb(mp, 0);
1610 	XFS_BUF_UNMANAGE(bp);
1611 	xfs_buf_relse(bp);
1612 	mp->m_sb_bp = NULL;
1613 }
1614 
1615 /*
1616  * See if the UUID is unique among mounted XFS filesystems.
1617  * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
1618  */
1619 STATIC int
1620 xfs_uuid_mount(
1621 	xfs_mount_t	*mp)
1622 {
1623 	if (uuid_is_nil(&mp->m_sb.sb_uuid)) {
1624 		cmn_err(CE_WARN,
1625 			"XFS: Filesystem %s has nil UUID - can't mount",
1626 			mp->m_fsname);
1627 		return -1;
1628 	}
1629 	if (!uuid_table_insert(&mp->m_sb.sb_uuid)) {
1630 		cmn_err(CE_WARN,
1631 			"XFS: Filesystem %s has duplicate UUID - can't mount",
1632 			mp->m_fsname);
1633 		return -1;
1634 	}
1635 	return 0;
1636 }
1637 
1638 /*
1639  * Remove filesystem from the UUID table.
1640  */
1641 STATIC void
1642 xfs_uuid_unmount(
1643 	xfs_mount_t	*mp)
1644 {
1645 	uuid_table_remove(&mp->m_sb.sb_uuid);
1646 }
1647 
1648 /*
1649  * Used to log changes to the superblock unit and width fields which could
1650  * be altered by the mount options. Only the first superblock is updated.
1651  */
1652 STATIC void
1653 xfs_mount_log_sbunit(
1654 	xfs_mount_t	*mp,
1655 	__int64_t	fields)
1656 {
1657 	xfs_trans_t	*tp;
1658 
1659 	ASSERT(fields & (XFS_SB_UNIT|XFS_SB_WIDTH|XFS_SB_UUID));
1660 
1661 	tp = xfs_trans_alloc(mp, XFS_TRANS_SB_UNIT);
1662 	if (xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0,
1663 				XFS_DEFAULT_LOG_COUNT)) {
1664 		xfs_trans_cancel(tp, 0);
1665 		return;
1666 	}
1667 	xfs_mod_sb(tp, fields);
1668 	xfs_trans_commit(tp, 0, NULL);
1669 }
1670 
1671 
1672 #ifdef HAVE_PERCPU_SB
1673 /*
1674  * Per-cpu incore superblock counters
1675  *
1676  * Simple concept, difficult implementation
1677  *
1678  * Basically, replace the incore superblock counters with a distributed per cpu
1679  * counter for contended fields (e.g.  free block count).
1680  *
1681  * Difficulties arise in that the incore sb is used for ENOSPC checking, and
1682  * hence needs to be accurately read when we are running low on space. Hence
1683  * there is a method to enable and disable the per-cpu counters based on how
1684  * much "stuff" is available in them.
1685  *
1686  * Basically, a counter is enabled if there is enough free resource to justify
1687  * running a per-cpu fast-path. If the per-cpu counter runs out (i.e. a local
1688  * ENOSPC), then we disable the counters to synchronise all callers and
1689  * re-distribute the available resources.
1690  *
1691  * If, once we redistributed the available resources, we still get a failure,
1692  * we disable the per-cpu counter and go through the slow path.
1693  *
1694  * The slow path is the current xfs_mod_incore_sb() function.  This means that
1695  * when we disable a per-cpu counter, we need to drain it's resources back to
1696  * the global superblock. We do this after disabling the counter to prevent
1697  * more threads from queueing up on the counter.
1698  *
1699  * Essentially, this means that we still need a lock in the fast path to enable
1700  * synchronisation between the global counters and the per-cpu counters. This
1701  * is not a problem because the lock will be local to a CPU almost all the time
1702  * and have little contention except when we get to ENOSPC conditions.
1703  *
1704  * Basically, this lock becomes a barrier that enables us to lock out the fast
1705  * path while we do things like enabling and disabling counters and
1706  * synchronising the counters.
1707  *
1708  * Locking rules:
1709  *
1710  * 	1. XFS_SB_LOCK() before picking up per-cpu locks
1711  * 	2. per-cpu locks always picked up via for_each_online_cpu() order
1712  * 	3. accurate counter sync requires XFS_SB_LOCK + per cpu locks
1713  * 	4. modifying per-cpu counters requires holding per-cpu lock
1714  * 	5. modifying global counters requires holding XFS_SB_LOCK
1715  *	6. enabling or disabling a counter requires holding the XFS_SB_LOCK
1716  *	   and _none_ of the per-cpu locks.
1717  *
1718  * Disabled counters are only ever re-enabled by a balance operation
1719  * that results in more free resources per CPU than a given threshold.
1720  * To ensure counters don't remain disabled, they are rebalanced when
1721  * the global resource goes above a higher threshold (i.e. some hysteresis
1722  * is present to prevent thrashing).
1723  */
1724 
1725 /*
1726  * hot-plug CPU notifier support.
1727  *
1728  * We cannot use the hotcpu_register() function because it does
1729  * not allow notifier instances. We need a notifier per filesystem
1730  * as we need to be able to identify the filesystem to balance
1731  * the counters out. This is achieved by having a notifier block
1732  * embedded in the xfs_mount_t and doing pointer magic to get the
1733  * mount pointer from the notifier block address.
1734  */
1735 STATIC int
1736 xfs_icsb_cpu_notify(
1737 	struct notifier_block *nfb,
1738 	unsigned long action,
1739 	void *hcpu)
1740 {
1741 	xfs_icsb_cnts_t *cntp;
1742 	xfs_mount_t	*mp;
1743 	int		s;
1744 
1745 	mp = (xfs_mount_t *)container_of(nfb, xfs_mount_t, m_icsb_notifier);
1746 	cntp = (xfs_icsb_cnts_t *)
1747 			per_cpu_ptr(mp->m_sb_cnts, (unsigned long)hcpu);
1748 	switch (action) {
1749 	case CPU_UP_PREPARE:
1750 		/* Easy Case - initialize the area and locks, and
1751 		 * then rebalance when online does everything else for us. */
1752 		memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
1753 		break;
1754 	case CPU_ONLINE:
1755 		xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0);
1756 		xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0);
1757 		xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0);
1758 		break;
1759 	case CPU_DEAD:
1760 		/* Disable all the counters, then fold the dead cpu's
1761 		 * count into the total on the global superblock and
1762 		 * re-enable the counters. */
1763 		s = XFS_SB_LOCK(mp);
1764 		xfs_icsb_disable_counter(mp, XFS_SBS_ICOUNT);
1765 		xfs_icsb_disable_counter(mp, XFS_SBS_IFREE);
1766 		xfs_icsb_disable_counter(mp, XFS_SBS_FDBLOCKS);
1767 
1768 		mp->m_sb.sb_icount += cntp->icsb_icount;
1769 		mp->m_sb.sb_ifree += cntp->icsb_ifree;
1770 		mp->m_sb.sb_fdblocks += cntp->icsb_fdblocks;
1771 
1772 		memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
1773 
1774 		xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, XFS_ICSB_SB_LOCKED);
1775 		xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, XFS_ICSB_SB_LOCKED);
1776 		xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, XFS_ICSB_SB_LOCKED);
1777 		XFS_SB_UNLOCK(mp, s);
1778 		break;
1779 	}
1780 
1781 	return NOTIFY_OK;
1782 }
1783 
1784 int
1785 xfs_icsb_init_counters(
1786 	xfs_mount_t	*mp)
1787 {
1788 	xfs_icsb_cnts_t *cntp;
1789 	int		i;
1790 
1791 	mp->m_sb_cnts = alloc_percpu(xfs_icsb_cnts_t);
1792 	if (mp->m_sb_cnts == NULL)
1793 		return -ENOMEM;
1794 
1795 	mp->m_icsb_notifier.notifier_call = xfs_icsb_cpu_notify;
1796 	mp->m_icsb_notifier.priority = 0;
1797 	register_cpu_notifier(&mp->m_icsb_notifier);
1798 
1799 	for_each_online_cpu(i) {
1800 		cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
1801 		memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
1802 	}
1803 	/*
1804 	 * start with all counters disabled so that the
1805 	 * initial balance kicks us off correctly
1806 	 */
1807 	mp->m_icsb_counters = -1;
1808 	return 0;
1809 }
1810 
1811 STATIC void
1812 xfs_icsb_destroy_counters(
1813 	xfs_mount_t	*mp)
1814 {
1815 	if (mp->m_sb_cnts) {
1816 		unregister_cpu_notifier(&mp->m_icsb_notifier);
1817 		free_percpu(mp->m_sb_cnts);
1818 	}
1819 }
1820 
1821 STATIC inline void
1822 xfs_icsb_lock_cntr(
1823 	xfs_icsb_cnts_t	*icsbp)
1824 {
1825 	while (test_and_set_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags)) {
1826 		ndelay(1000);
1827 	}
1828 }
1829 
1830 STATIC inline void
1831 xfs_icsb_unlock_cntr(
1832 	xfs_icsb_cnts_t	*icsbp)
1833 {
1834 	clear_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags);
1835 }
1836 
1837 
1838 STATIC inline void
1839 xfs_icsb_lock_all_counters(
1840 	xfs_mount_t	*mp)
1841 {
1842 	xfs_icsb_cnts_t *cntp;
1843 	int		i;
1844 
1845 	for_each_online_cpu(i) {
1846 		cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
1847 		xfs_icsb_lock_cntr(cntp);
1848 	}
1849 }
1850 
1851 STATIC inline void
1852 xfs_icsb_unlock_all_counters(
1853 	xfs_mount_t	*mp)
1854 {
1855 	xfs_icsb_cnts_t *cntp;
1856 	int		i;
1857 
1858 	for_each_online_cpu(i) {
1859 		cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
1860 		xfs_icsb_unlock_cntr(cntp);
1861 	}
1862 }
1863 
1864 STATIC void
1865 xfs_icsb_count(
1866 	xfs_mount_t	*mp,
1867 	xfs_icsb_cnts_t	*cnt,
1868 	int		flags)
1869 {
1870 	xfs_icsb_cnts_t *cntp;
1871 	int		i;
1872 
1873 	memset(cnt, 0, sizeof(xfs_icsb_cnts_t));
1874 
1875 	if (!(flags & XFS_ICSB_LAZY_COUNT))
1876 		xfs_icsb_lock_all_counters(mp);
1877 
1878 	for_each_online_cpu(i) {
1879 		cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
1880 		cnt->icsb_icount += cntp->icsb_icount;
1881 		cnt->icsb_ifree += cntp->icsb_ifree;
1882 		cnt->icsb_fdblocks += cntp->icsb_fdblocks;
1883 	}
1884 
1885 	if (!(flags & XFS_ICSB_LAZY_COUNT))
1886 		xfs_icsb_unlock_all_counters(mp);
1887 }
1888 
1889 STATIC int
1890 xfs_icsb_counter_disabled(
1891 	xfs_mount_t	*mp,
1892 	xfs_sb_field_t	field)
1893 {
1894 	ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
1895 	return test_bit(field, &mp->m_icsb_counters);
1896 }
1897 
1898 STATIC int
1899 xfs_icsb_disable_counter(
1900 	xfs_mount_t	*mp,
1901 	xfs_sb_field_t	field)
1902 {
1903 	xfs_icsb_cnts_t	cnt;
1904 
1905 	ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
1906 
1907 	xfs_icsb_lock_all_counters(mp);
1908 	if (!test_and_set_bit(field, &mp->m_icsb_counters)) {
1909 		/* drain back to superblock */
1910 
1911 		xfs_icsb_count(mp, &cnt, XFS_ICSB_SB_LOCKED|XFS_ICSB_LAZY_COUNT);
1912 		switch(field) {
1913 		case XFS_SBS_ICOUNT:
1914 			mp->m_sb.sb_icount = cnt.icsb_icount;
1915 			break;
1916 		case XFS_SBS_IFREE:
1917 			mp->m_sb.sb_ifree = cnt.icsb_ifree;
1918 			break;
1919 		case XFS_SBS_FDBLOCKS:
1920 			mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
1921 			break;
1922 		default:
1923 			BUG();
1924 		}
1925 	}
1926 
1927 	xfs_icsb_unlock_all_counters(mp);
1928 
1929 	return 0;
1930 }
1931 
1932 STATIC void
1933 xfs_icsb_enable_counter(
1934 	xfs_mount_t	*mp,
1935 	xfs_sb_field_t	field,
1936 	uint64_t	count,
1937 	uint64_t	resid)
1938 {
1939 	xfs_icsb_cnts_t	*cntp;
1940 	int		i;
1941 
1942 	ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
1943 
1944 	xfs_icsb_lock_all_counters(mp);
1945 	for_each_online_cpu(i) {
1946 		cntp = per_cpu_ptr(mp->m_sb_cnts, i);
1947 		switch (field) {
1948 		case XFS_SBS_ICOUNT:
1949 			cntp->icsb_icount = count + resid;
1950 			break;
1951 		case XFS_SBS_IFREE:
1952 			cntp->icsb_ifree = count + resid;
1953 			break;
1954 		case XFS_SBS_FDBLOCKS:
1955 			cntp->icsb_fdblocks = count + resid;
1956 			break;
1957 		default:
1958 			BUG();
1959 			break;
1960 		}
1961 		resid = 0;
1962 	}
1963 	clear_bit(field, &mp->m_icsb_counters);
1964 	xfs_icsb_unlock_all_counters(mp);
1965 }
1966 
1967 STATIC void
1968 xfs_icsb_sync_counters_int(
1969 	xfs_mount_t	*mp,
1970 	int		flags)
1971 {
1972 	xfs_icsb_cnts_t	cnt;
1973 	int		s;
1974 
1975 	/* Pass 1: lock all counters */
1976 	if ((flags & XFS_ICSB_SB_LOCKED) == 0)
1977 		s = XFS_SB_LOCK(mp);
1978 
1979 	xfs_icsb_count(mp, &cnt, flags);
1980 
1981 	/* Step 3: update mp->m_sb fields */
1982 	if (!xfs_icsb_counter_disabled(mp, XFS_SBS_ICOUNT))
1983 		mp->m_sb.sb_icount = cnt.icsb_icount;
1984 	if (!xfs_icsb_counter_disabled(mp, XFS_SBS_IFREE))
1985 		mp->m_sb.sb_ifree = cnt.icsb_ifree;
1986 	if (!xfs_icsb_counter_disabled(mp, XFS_SBS_FDBLOCKS))
1987 		mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
1988 
1989 	if ((flags & XFS_ICSB_SB_LOCKED) == 0)
1990 		XFS_SB_UNLOCK(mp, s);
1991 }
1992 
1993 /*
1994  * Accurate update of per-cpu counters to incore superblock
1995  */
1996 STATIC void
1997 xfs_icsb_sync_counters(
1998 	xfs_mount_t	*mp)
1999 {
2000 	xfs_icsb_sync_counters_int(mp, 0);
2001 }
2002 
2003 /*
2004  * lazy addition used for things like df, background sb syncs, etc
2005  */
2006 void
2007 xfs_icsb_sync_counters_lazy(
2008 	xfs_mount_t	*mp)
2009 {
2010 	xfs_icsb_sync_counters_int(mp, XFS_ICSB_LAZY_COUNT);
2011 }
2012 
2013 /*
2014  * Balance and enable/disable counters as necessary.
2015  *
2016  * Thresholds for re-enabling counters are somewhat magic.
2017  * inode counts are chosen to be the same number as single
2018  * on disk allocation chunk per CPU, and free blocks is
2019  * something far enough zero that we aren't going thrash
2020  * when we get near ENOSPC.
2021  */
2022 #define XFS_ICSB_INO_CNTR_REENABLE	64
2023 #define XFS_ICSB_FDBLK_CNTR_REENABLE	512
2024 STATIC void
2025 xfs_icsb_balance_counter(
2026 	xfs_mount_t	*mp,
2027 	xfs_sb_field_t  field,
2028 	int		flags)
2029 {
2030 	uint64_t	count, resid = 0;
2031 	int		weight = num_online_cpus();
2032 	int		s;
2033 
2034 	if (!(flags & XFS_ICSB_SB_LOCKED))
2035 		s = XFS_SB_LOCK(mp);
2036 
2037 	/* disable counter and sync counter */
2038 	xfs_icsb_disable_counter(mp, field);
2039 
2040 	/* update counters  - first CPU gets residual*/
2041 	switch (field) {
2042 	case XFS_SBS_ICOUNT:
2043 		count = mp->m_sb.sb_icount;
2044 		resid = do_div(count, weight);
2045 		if (count < XFS_ICSB_INO_CNTR_REENABLE)
2046 			goto out;
2047 		break;
2048 	case XFS_SBS_IFREE:
2049 		count = mp->m_sb.sb_ifree;
2050 		resid = do_div(count, weight);
2051 		if (count < XFS_ICSB_INO_CNTR_REENABLE)
2052 			goto out;
2053 		break;
2054 	case XFS_SBS_FDBLOCKS:
2055 		count = mp->m_sb.sb_fdblocks;
2056 		resid = do_div(count, weight);
2057 		if (count < XFS_ICSB_FDBLK_CNTR_REENABLE)
2058 			goto out;
2059 		break;
2060 	default:
2061 		BUG();
2062 		break;
2063 	}
2064 
2065 	xfs_icsb_enable_counter(mp, field, count, resid);
2066 out:
2067 	if (!(flags & XFS_ICSB_SB_LOCKED))
2068 		XFS_SB_UNLOCK(mp, s);
2069 }
2070 
2071 STATIC int
2072 xfs_icsb_modify_counters_int(
2073 	xfs_mount_t	*mp,
2074 	xfs_sb_field_t	field,
2075 	int		delta,
2076 	int		rsvd,
2077 	int		flags)
2078 {
2079 	xfs_icsb_cnts_t	*icsbp;
2080 	long long	lcounter;	/* long counter for 64 bit fields */
2081 	int		cpu, s, locked = 0;
2082 	int		ret = 0, balance_done = 0;
2083 
2084 again:
2085 	cpu = get_cpu();
2086 	icsbp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, cpu),
2087 	xfs_icsb_lock_cntr(icsbp);
2088 	if (unlikely(xfs_icsb_counter_disabled(mp, field)))
2089 		goto slow_path;
2090 
2091 	switch (field) {
2092 	case XFS_SBS_ICOUNT:
2093 		lcounter = icsbp->icsb_icount;
2094 		lcounter += delta;
2095 		if (unlikely(lcounter < 0))
2096 			goto slow_path;
2097 		icsbp->icsb_icount = lcounter;
2098 		break;
2099 
2100 	case XFS_SBS_IFREE:
2101 		lcounter = icsbp->icsb_ifree;
2102 		lcounter += delta;
2103 		if (unlikely(lcounter < 0))
2104 			goto slow_path;
2105 		icsbp->icsb_ifree = lcounter;
2106 		break;
2107 
2108 	case XFS_SBS_FDBLOCKS:
2109 		BUG_ON((mp->m_resblks - mp->m_resblks_avail) != 0);
2110 
2111 		lcounter = icsbp->icsb_fdblocks;
2112 		lcounter += delta;
2113 		if (unlikely(lcounter < 0))
2114 			goto slow_path;
2115 		icsbp->icsb_fdblocks = lcounter;
2116 		break;
2117 	default:
2118 		BUG();
2119 		break;
2120 	}
2121 	xfs_icsb_unlock_cntr(icsbp);
2122 	put_cpu();
2123 	if (locked)
2124 		XFS_SB_UNLOCK(mp, s);
2125 	return 0;
2126 
2127 	/*
2128 	 * The slow path needs to be run with the SBLOCK
2129 	 * held so that we prevent other threads from
2130 	 * attempting to run this path at the same time.
2131 	 * this provides exclusion for the balancing code,
2132 	 * and exclusive fallback if the balance does not
2133 	 * provide enough resources to continue in an unlocked
2134 	 * manner.
2135 	 */
2136 slow_path:
2137 	xfs_icsb_unlock_cntr(icsbp);
2138 	put_cpu();
2139 
2140 	/* need to hold superblock incase we need
2141 	 * to disable a counter */
2142 	if (!(flags & XFS_ICSB_SB_LOCKED)) {
2143 		s = XFS_SB_LOCK(mp);
2144 		locked = 1;
2145 		flags |= XFS_ICSB_SB_LOCKED;
2146 	}
2147 	if (!balance_done) {
2148 		xfs_icsb_balance_counter(mp, field, flags);
2149 		balance_done = 1;
2150 		goto again;
2151 	} else {
2152 		/*
2153 		 * we might not have enough on this local
2154 		 * cpu to allocate for a bulk request.
2155 		 * We need to drain this field from all CPUs
2156 		 * and disable the counter fastpath
2157 		 */
2158 		xfs_icsb_disable_counter(mp, field);
2159 	}
2160 
2161 	ret = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
2162 
2163 	if (locked)
2164 		XFS_SB_UNLOCK(mp, s);
2165 	return ret;
2166 }
2167 
2168 STATIC int
2169 xfs_icsb_modify_counters(
2170 	xfs_mount_t	*mp,
2171 	xfs_sb_field_t	field,
2172 	int		delta,
2173 	int		rsvd)
2174 {
2175 	return xfs_icsb_modify_counters_int(mp, field, delta, rsvd, 0);
2176 }
2177 
2178 /*
2179  * Called when superblock is already locked
2180  */
2181 STATIC int
2182 xfs_icsb_modify_counters_locked(
2183 	xfs_mount_t	*mp,
2184 	xfs_sb_field_t	field,
2185 	int		delta,
2186 	int		rsvd)
2187 {
2188 	return xfs_icsb_modify_counters_int(mp, field, delta,
2189 						rsvd, XFS_ICSB_SB_LOCKED);
2190 }
2191 #endif
2192