xref: /linux/fs/xfs/xfs_mount.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
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_dir2.h"
28 #include "xfs_dmapi.h"
29 #include "xfs_mount.h"
30 #include "xfs_bmap_btree.h"
31 #include "xfs_alloc_btree.h"
32 #include "xfs_ialloc_btree.h"
33 #include "xfs_dir2_sf.h"
34 #include "xfs_attr_sf.h"
35 #include "xfs_dinode.h"
36 #include "xfs_inode.h"
37 #include "xfs_btree.h"
38 #include "xfs_ialloc.h"
39 #include "xfs_alloc.h"
40 #include "xfs_rtalloc.h"
41 #include "xfs_bmap.h"
42 #include "xfs_error.h"
43 #include "xfs_rw.h"
44 #include "xfs_quota.h"
45 #include "xfs_fsops.h"
46 
47 STATIC void	xfs_mount_log_sbunit(xfs_mount_t *, __int64_t);
48 STATIC int	xfs_uuid_mount(xfs_mount_t *);
49 STATIC void	xfs_uuid_unmount(xfs_mount_t *mp);
50 STATIC void	xfs_unmountfs_wait(xfs_mount_t *);
51 
52 
53 #ifdef HAVE_PERCPU_SB
54 STATIC void	xfs_icsb_destroy_counters(xfs_mount_t *);
55 STATIC void	xfs_icsb_balance_counter(xfs_mount_t *, xfs_sb_field_t, int);
56 STATIC void	xfs_icsb_sync_counters(xfs_mount_t *);
57 STATIC int	xfs_icsb_modify_counters(xfs_mount_t *, xfs_sb_field_t,
58 						int, int);
59 STATIC int	xfs_icsb_modify_counters_locked(xfs_mount_t *, xfs_sb_field_t,
60 						int, int);
61 STATIC int	xfs_icsb_disable_counter(xfs_mount_t *, xfs_sb_field_t);
62 
63 #else
64 
65 #define xfs_icsb_destroy_counters(mp)			do { } while (0)
66 #define xfs_icsb_balance_counter(mp, a, b)		do { } while (0)
67 #define xfs_icsb_sync_counters(mp)			do { } while (0)
68 #define xfs_icsb_modify_counters(mp, a, b, c)		do { } while (0)
69 #define xfs_icsb_modify_counters_locked(mp, a, b, c)	do { } while (0)
70 
71 #endif
72 
73 static const struct {
74 	short offset;
75 	short type;	/* 0 = integer
76 			 * 1 = binary / string (no translation)
77 			 */
78 } xfs_sb_info[] = {
79     { offsetof(xfs_sb_t, sb_magicnum),   0 },
80     { offsetof(xfs_sb_t, sb_blocksize),  0 },
81     { offsetof(xfs_sb_t, sb_dblocks),    0 },
82     { offsetof(xfs_sb_t, sb_rblocks),    0 },
83     { offsetof(xfs_sb_t, sb_rextents),   0 },
84     { offsetof(xfs_sb_t, sb_uuid),       1 },
85     { offsetof(xfs_sb_t, sb_logstart),   0 },
86     { offsetof(xfs_sb_t, sb_rootino),    0 },
87     { offsetof(xfs_sb_t, sb_rbmino),     0 },
88     { offsetof(xfs_sb_t, sb_rsumino),    0 },
89     { offsetof(xfs_sb_t, sb_rextsize),   0 },
90     { offsetof(xfs_sb_t, sb_agblocks),   0 },
91     { offsetof(xfs_sb_t, sb_agcount),    0 },
92     { offsetof(xfs_sb_t, sb_rbmblocks),  0 },
93     { offsetof(xfs_sb_t, sb_logblocks),  0 },
94     { offsetof(xfs_sb_t, sb_versionnum), 0 },
95     { offsetof(xfs_sb_t, sb_sectsize),   0 },
96     { offsetof(xfs_sb_t, sb_inodesize),  0 },
97     { offsetof(xfs_sb_t, sb_inopblock),  0 },
98     { offsetof(xfs_sb_t, sb_fname[0]),   1 },
99     { offsetof(xfs_sb_t, sb_blocklog),   0 },
100     { offsetof(xfs_sb_t, sb_sectlog),    0 },
101     { offsetof(xfs_sb_t, sb_inodelog),   0 },
102     { offsetof(xfs_sb_t, sb_inopblog),   0 },
103     { offsetof(xfs_sb_t, sb_agblklog),   0 },
104     { offsetof(xfs_sb_t, sb_rextslog),   0 },
105     { offsetof(xfs_sb_t, sb_inprogress), 0 },
106     { offsetof(xfs_sb_t, sb_imax_pct),   0 },
107     { offsetof(xfs_sb_t, sb_icount),     0 },
108     { offsetof(xfs_sb_t, sb_ifree),      0 },
109     { offsetof(xfs_sb_t, sb_fdblocks),   0 },
110     { offsetof(xfs_sb_t, sb_frextents),  0 },
111     { offsetof(xfs_sb_t, sb_uquotino),   0 },
112     { offsetof(xfs_sb_t, sb_gquotino),   0 },
113     { offsetof(xfs_sb_t, sb_qflags),     0 },
114     { offsetof(xfs_sb_t, sb_flags),      0 },
115     { offsetof(xfs_sb_t, sb_shared_vn),  0 },
116     { offsetof(xfs_sb_t, sb_inoalignmt), 0 },
117     { offsetof(xfs_sb_t, sb_unit),	 0 },
118     { offsetof(xfs_sb_t, sb_width),	 0 },
119     { offsetof(xfs_sb_t, sb_dirblklog),	 0 },
120     { offsetof(xfs_sb_t, sb_logsectlog), 0 },
121     { offsetof(xfs_sb_t, sb_logsectsize),0 },
122     { offsetof(xfs_sb_t, sb_logsunit),	 0 },
123     { offsetof(xfs_sb_t, sb_features2),	 0 },
124     { sizeof(xfs_sb_t),			 0 }
125 };
126 
127 /*
128  * Return a pointer to an initialized xfs_mount structure.
129  */
130 xfs_mount_t *
131 xfs_mount_init(void)
132 {
133 	xfs_mount_t *mp;
134 
135 	mp = kmem_zalloc(sizeof(xfs_mount_t), KM_SLEEP);
136 
137 	if (xfs_icsb_init_counters(mp)) {
138 		mp->m_flags |= XFS_MOUNT_NO_PERCPU_SB;
139 	}
140 
141 	AIL_LOCKINIT(&mp->m_ail_lock, "xfs_ail");
142 	spinlock_init(&mp->m_sb_lock, "xfs_sb");
143 	mutex_init(&mp->m_ilock);
144 	initnsema(&mp->m_growlock, 1, "xfs_grow");
145 	/*
146 	 * Initialize the AIL.
147 	 */
148 	xfs_trans_ail_init(mp);
149 
150 	atomic_set(&mp->m_active_trans, 0);
151 
152 	return mp;
153 }
154 
155 /*
156  * Free up the resources associated with a mount structure.  Assume that
157  * the structure was initially zeroed, so we can tell which fields got
158  * initialized.
159  */
160 void
161 xfs_mount_free(
162 	xfs_mount_t	*mp,
163 	int		remove_bhv)
164 {
165 	if (mp->m_ihash)
166 		xfs_ihash_free(mp);
167 	if (mp->m_chash)
168 		xfs_chash_free(mp);
169 
170 	if (mp->m_perag) {
171 		int	agno;
172 
173 		for (agno = 0; agno < mp->m_maxagi; agno++)
174 			if (mp->m_perag[agno].pagb_list)
175 				kmem_free(mp->m_perag[agno].pagb_list,
176 						sizeof(xfs_perag_busy_t) *
177 							XFS_PAGB_NUM_SLOTS);
178 		kmem_free(mp->m_perag,
179 			  sizeof(xfs_perag_t) * mp->m_sb.sb_agcount);
180 	}
181 
182 	AIL_LOCK_DESTROY(&mp->m_ail_lock);
183 	spinlock_destroy(&mp->m_sb_lock);
184 	mutex_destroy(&mp->m_ilock);
185 	freesema(&mp->m_growlock);
186 	if (mp->m_quotainfo)
187 		XFS_QM_DONE(mp);
188 
189 	if (mp->m_fsname != NULL)
190 		kmem_free(mp->m_fsname, mp->m_fsname_len);
191 	if (mp->m_rtname != NULL)
192 		kmem_free(mp->m_rtname, strlen(mp->m_rtname) + 1);
193 	if (mp->m_logname != NULL)
194 		kmem_free(mp->m_logname, strlen(mp->m_logname) + 1);
195 
196 	if (remove_bhv) {
197 		struct bhv_vfs	*vfsp = XFS_MTOVFS(mp);
198 
199 		bhv_remove_all_vfsops(vfsp, 0);
200 		VFS_REMOVEBHV(vfsp, &mp->m_bhv);
201 	}
202 
203 	xfs_icsb_destroy_counters(mp);
204 	kmem_free(mp, sizeof(xfs_mount_t));
205 }
206 
207 
208 /*
209  * Check the validity of the SB found.
210  */
211 STATIC int
212 xfs_mount_validate_sb(
213 	xfs_mount_t	*mp,
214 	xfs_sb_t	*sbp,
215 	int		flags)
216 {
217 	/*
218 	 * If the log device and data device have the
219 	 * same device number, the log is internal.
220 	 * Consequently, the sb_logstart should be non-zero.  If
221 	 * we have a zero sb_logstart in this case, we may be trying to mount
222 	 * a volume filesystem in a non-volume manner.
223 	 */
224 	if (sbp->sb_magicnum != XFS_SB_MAGIC) {
225 		xfs_fs_mount_cmn_err(flags, "bad magic number");
226 		return XFS_ERROR(EWRONGFS);
227 	}
228 
229 	if (!XFS_SB_GOOD_VERSION(sbp)) {
230 		xfs_fs_mount_cmn_err(flags, "bad version");
231 		return XFS_ERROR(EWRONGFS);
232 	}
233 
234 	if (unlikely(
235 	    sbp->sb_logstart == 0 && mp->m_logdev_targp == mp->m_ddev_targp)) {
236 		xfs_fs_mount_cmn_err(flags,
237 			"filesystem is marked as having an external log; "
238 			"specify logdev on the\nmount command line.");
239 		return XFS_ERROR(EINVAL);
240 	}
241 
242 	if (unlikely(
243 	    sbp->sb_logstart != 0 && mp->m_logdev_targp != mp->m_ddev_targp)) {
244 		xfs_fs_mount_cmn_err(flags,
245 			"filesystem is marked as having an internal log; "
246 			"do not specify logdev on\nthe mount command line.");
247 		return XFS_ERROR(EINVAL);
248 	}
249 
250 	/*
251 	 * More sanity checking. These were stolen directly from
252 	 * xfs_repair.
253 	 */
254 	if (unlikely(
255 	    sbp->sb_agcount <= 0					||
256 	    sbp->sb_sectsize < XFS_MIN_SECTORSIZE			||
257 	    sbp->sb_sectsize > XFS_MAX_SECTORSIZE			||
258 	    sbp->sb_sectlog < XFS_MIN_SECTORSIZE_LOG			||
259 	    sbp->sb_sectlog > XFS_MAX_SECTORSIZE_LOG			||
260 	    sbp->sb_blocksize < XFS_MIN_BLOCKSIZE			||
261 	    sbp->sb_blocksize > XFS_MAX_BLOCKSIZE			||
262 	    sbp->sb_blocklog < XFS_MIN_BLOCKSIZE_LOG			||
263 	    sbp->sb_blocklog > XFS_MAX_BLOCKSIZE_LOG			||
264 	    sbp->sb_inodesize < XFS_DINODE_MIN_SIZE			||
265 	    sbp->sb_inodesize > XFS_DINODE_MAX_SIZE			||
266 	    sbp->sb_inodelog < XFS_DINODE_MIN_LOG			||
267 	    sbp->sb_inodelog > XFS_DINODE_MAX_LOG			||
268 	    (sbp->sb_blocklog - sbp->sb_inodelog != sbp->sb_inopblog)	||
269 	    (sbp->sb_rextsize * sbp->sb_blocksize > XFS_MAX_RTEXTSIZE)	||
270 	    (sbp->sb_rextsize * sbp->sb_blocksize < XFS_MIN_RTEXTSIZE)	||
271 	    (sbp->sb_imax_pct > 100 /* zero sb_imax_pct is valid */))) {
272 		xfs_fs_mount_cmn_err(flags, "SB sanity check 1 failed");
273 		return XFS_ERROR(EFSCORRUPTED);
274 	}
275 
276 	/*
277 	 * Sanity check AG count, size fields against data size field
278 	 */
279 	if (unlikely(
280 	    sbp->sb_dblocks == 0 ||
281 	    sbp->sb_dblocks >
282 	     (xfs_drfsbno_t)sbp->sb_agcount * sbp->sb_agblocks ||
283 	    sbp->sb_dblocks < (xfs_drfsbno_t)(sbp->sb_agcount - 1) *
284 			      sbp->sb_agblocks + XFS_MIN_AG_BLOCKS)) {
285 		xfs_fs_mount_cmn_err(flags, "SB sanity check 2 failed");
286 		return XFS_ERROR(EFSCORRUPTED);
287 	}
288 
289 	ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
290 	ASSERT(sbp->sb_blocklog >= BBSHIFT);
291 
292 #if XFS_BIG_BLKNOS     /* Limited by ULONG_MAX of page cache index */
293 	if (unlikely(
294 	    (sbp->sb_dblocks >> (PAGE_SHIFT - sbp->sb_blocklog)) > ULONG_MAX ||
295 	    (sbp->sb_rblocks >> (PAGE_SHIFT - sbp->sb_blocklog)) > ULONG_MAX)) {
296 #else                  /* Limited by UINT_MAX of sectors */
297 	if (unlikely(
298 	    (sbp->sb_dblocks << (sbp->sb_blocklog - BBSHIFT)) > UINT_MAX ||
299 	    (sbp->sb_rblocks << (sbp->sb_blocklog - BBSHIFT)) > UINT_MAX)) {
300 #endif
301 		xfs_fs_mount_cmn_err(flags,
302 			"file system too large to be mounted on this system.");
303 		return XFS_ERROR(E2BIG);
304 	}
305 
306 	if (unlikely(sbp->sb_inprogress)) {
307 		xfs_fs_mount_cmn_err(flags, "file system busy");
308 		return XFS_ERROR(EFSCORRUPTED);
309 	}
310 
311 	/*
312 	 * Version 1 directory format has never worked on Linux.
313 	 */
314 	if (unlikely(!XFS_SB_VERSION_HASDIRV2(sbp))) {
315 		xfs_fs_mount_cmn_err(flags,
316 			"file system using version 1 directory format");
317 		return XFS_ERROR(ENOSYS);
318 	}
319 
320 	/*
321 	 * Until this is fixed only page-sized or smaller data blocks work.
322 	 */
323 	if (unlikely(sbp->sb_blocksize > PAGE_SIZE)) {
324 		xfs_fs_mount_cmn_err(flags,
325 			"file system with blocksize %d bytes",
326 			sbp->sb_blocksize);
327 		xfs_fs_mount_cmn_err(flags,
328 			"only pagesize (%ld) or less will currently work.",
329 			PAGE_SIZE);
330 		return XFS_ERROR(ENOSYS);
331 	}
332 
333 	return 0;
334 }
335 
336 xfs_agnumber_t
337 xfs_initialize_perag(
338 	bhv_vfs_t	*vfs,
339 	xfs_mount_t	*mp,
340 	xfs_agnumber_t	agcount)
341 {
342 	xfs_agnumber_t	index, max_metadata;
343 	xfs_perag_t	*pag;
344 	xfs_agino_t	agino;
345 	xfs_ino_t	ino;
346 	xfs_sb_t	*sbp = &mp->m_sb;
347 	xfs_ino_t	max_inum = XFS_MAXINUMBER_32;
348 
349 	/* Check to see if the filesystem can overflow 32 bit inodes */
350 	agino = XFS_OFFBNO_TO_AGINO(mp, sbp->sb_agblocks - 1, 0);
351 	ino = XFS_AGINO_TO_INO(mp, agcount - 1, agino);
352 
353 	/* Clear the mount flag if no inode can overflow 32 bits
354 	 * on this filesystem, or if specifically requested..
355 	 */
356 	if ((vfs->vfs_flag & VFS_32BITINODES) && ino > max_inum) {
357 		mp->m_flags |= XFS_MOUNT_32BITINODES;
358 	} else {
359 		mp->m_flags &= ~XFS_MOUNT_32BITINODES;
360 	}
361 
362 	/* If we can overflow then setup the ag headers accordingly */
363 	if (mp->m_flags & XFS_MOUNT_32BITINODES) {
364 		/* Calculate how much should be reserved for inodes to
365 		 * meet the max inode percentage.
366 		 */
367 		if (mp->m_maxicount) {
368 			__uint64_t	icount;
369 
370 			icount = sbp->sb_dblocks * sbp->sb_imax_pct;
371 			do_div(icount, 100);
372 			icount += sbp->sb_agblocks - 1;
373 			do_div(icount, sbp->sb_agblocks);
374 			max_metadata = icount;
375 		} else {
376 			max_metadata = agcount;
377 		}
378 		for (index = 0; index < agcount; index++) {
379 			ino = XFS_AGINO_TO_INO(mp, index, agino);
380 			if (ino > max_inum) {
381 				index++;
382 				break;
383 			}
384 
385 			/* This ag is preferred for inodes */
386 			pag = &mp->m_perag[index];
387 			pag->pagi_inodeok = 1;
388 			if (index < max_metadata)
389 				pag->pagf_metadata = 1;
390 		}
391 	} else {
392 		/* Setup default behavior for smaller filesystems */
393 		for (index = 0; index < agcount; index++) {
394 			pag = &mp->m_perag[index];
395 			pag->pagi_inodeok = 1;
396 		}
397 	}
398 	return index;
399 }
400 
401 /*
402  * xfs_xlatesb
403  *
404  *     data       - on disk version of sb
405  *     sb         - a superblock
406  *     dir        - conversion direction: <0 - convert sb to buf
407  *                                        >0 - convert buf to sb
408  *     fields     - which fields to copy (bitmask)
409  */
410 void
411 xfs_xlatesb(
412 	void		*data,
413 	xfs_sb_t	*sb,
414 	int		dir,
415 	__int64_t	fields)
416 {
417 	xfs_caddr_t	buf_ptr;
418 	xfs_caddr_t	mem_ptr;
419 	xfs_sb_field_t	f;
420 	int		first;
421 	int		size;
422 
423 	ASSERT(dir);
424 	ASSERT(fields);
425 
426 	if (!fields)
427 		return;
428 
429 	buf_ptr = (xfs_caddr_t)data;
430 	mem_ptr = (xfs_caddr_t)sb;
431 
432 	while (fields) {
433 		f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
434 		first = xfs_sb_info[f].offset;
435 		size = xfs_sb_info[f + 1].offset - first;
436 
437 		ASSERT(xfs_sb_info[f].type == 0 || xfs_sb_info[f].type == 1);
438 
439 		if (size == 1 || xfs_sb_info[f].type == 1) {
440 			if (dir > 0) {
441 				memcpy(mem_ptr + first, buf_ptr + first, size);
442 			} else {
443 				memcpy(buf_ptr + first, mem_ptr + first, size);
444 			}
445 		} else {
446 			switch (size) {
447 			case 2:
448 				INT_XLATE(*(__uint16_t*)(buf_ptr+first),
449 					  *(__uint16_t*)(mem_ptr+first),
450 					  dir, ARCH_CONVERT);
451 				break;
452 			case 4:
453 				INT_XLATE(*(__uint32_t*)(buf_ptr+first),
454 					  *(__uint32_t*)(mem_ptr+first),
455 					  dir, ARCH_CONVERT);
456 				break;
457 			case 8:
458 				INT_XLATE(*(__uint64_t*)(buf_ptr+first),
459 					  *(__uint64_t*)(mem_ptr+first), dir, ARCH_CONVERT);
460 				break;
461 			default:
462 				ASSERT(0);
463 			}
464 		}
465 
466 		fields &= ~(1LL << f);
467 	}
468 }
469 
470 /*
471  * xfs_readsb
472  *
473  * Does the initial read of the superblock.
474  */
475 int
476 xfs_readsb(xfs_mount_t *mp, int flags)
477 {
478 	unsigned int	sector_size;
479 	unsigned int	extra_flags;
480 	xfs_buf_t	*bp;
481 	xfs_sb_t	*sbp;
482 	int		error;
483 
484 	ASSERT(mp->m_sb_bp == NULL);
485 	ASSERT(mp->m_ddev_targp != NULL);
486 
487 	/*
488 	 * Allocate a (locked) buffer to hold the superblock.
489 	 * This will be kept around at all times to optimize
490 	 * access to the superblock.
491 	 */
492 	sector_size = xfs_getsize_buftarg(mp->m_ddev_targp);
493 	extra_flags = XFS_BUF_LOCK | XFS_BUF_MANAGE | XFS_BUF_MAPPED;
494 
495 	bp = xfs_buf_read_flags(mp->m_ddev_targp, XFS_SB_DADDR,
496 				BTOBB(sector_size), extra_flags);
497 	if (!bp || XFS_BUF_ISERROR(bp)) {
498 		xfs_fs_mount_cmn_err(flags, "SB read failed");
499 		error = bp ? XFS_BUF_GETERROR(bp) : ENOMEM;
500 		goto fail;
501 	}
502 	ASSERT(XFS_BUF_ISBUSY(bp));
503 	ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
504 
505 	/*
506 	 * Initialize the mount structure from the superblock.
507 	 * But first do some basic consistency checking.
508 	 */
509 	sbp = XFS_BUF_TO_SBP(bp);
510 	xfs_xlatesb(XFS_BUF_PTR(bp), &(mp->m_sb), 1, XFS_SB_ALL_BITS);
511 
512 	error = xfs_mount_validate_sb(mp, &(mp->m_sb), flags);
513 	if (error) {
514 		xfs_fs_mount_cmn_err(flags, "SB validate failed");
515 		goto fail;
516 	}
517 
518 	/*
519 	 * We must be able to do sector-sized and sector-aligned IO.
520 	 */
521 	if (sector_size > mp->m_sb.sb_sectsize) {
522 		xfs_fs_mount_cmn_err(flags,
523 			"device supports only %u byte sectors (not %u)",
524 			sector_size, mp->m_sb.sb_sectsize);
525 		error = ENOSYS;
526 		goto fail;
527 	}
528 
529 	/*
530 	 * If device sector size is smaller than the superblock size,
531 	 * re-read the superblock so the buffer is correctly sized.
532 	 */
533 	if (sector_size < mp->m_sb.sb_sectsize) {
534 		XFS_BUF_UNMANAGE(bp);
535 		xfs_buf_relse(bp);
536 		sector_size = mp->m_sb.sb_sectsize;
537 		bp = xfs_buf_read_flags(mp->m_ddev_targp, XFS_SB_DADDR,
538 					BTOBB(sector_size), extra_flags);
539 		if (!bp || XFS_BUF_ISERROR(bp)) {
540 			xfs_fs_mount_cmn_err(flags, "SB re-read failed");
541 			error = bp ? XFS_BUF_GETERROR(bp) : ENOMEM;
542 			goto fail;
543 		}
544 		ASSERT(XFS_BUF_ISBUSY(bp));
545 		ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
546 	}
547 
548 	xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0);
549 	xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0);
550 	xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0);
551 
552 	mp->m_sb_bp = bp;
553 	xfs_buf_relse(bp);
554 	ASSERT(XFS_BUF_VALUSEMA(bp) > 0);
555 	return 0;
556 
557  fail:
558 	if (bp) {
559 		XFS_BUF_UNMANAGE(bp);
560 		xfs_buf_relse(bp);
561 	}
562 	return error;
563 }
564 
565 
566 /*
567  * xfs_mount_common
568  *
569  * Mount initialization code establishing various mount
570  * fields from the superblock associated with the given
571  * mount structure
572  */
573 STATIC void
574 xfs_mount_common(xfs_mount_t *mp, xfs_sb_t *sbp)
575 {
576 	int	i;
577 
578 	mp->m_agfrotor = mp->m_agirotor = 0;
579 	spinlock_init(&mp->m_agirotor_lock, "m_agirotor_lock");
580 	mp->m_maxagi = mp->m_sb.sb_agcount;
581 	mp->m_blkbit_log = sbp->sb_blocklog + XFS_NBBYLOG;
582 	mp->m_blkbb_log = sbp->sb_blocklog - BBSHIFT;
583 	mp->m_sectbb_log = sbp->sb_sectlog - BBSHIFT;
584 	mp->m_agno_log = xfs_highbit32(sbp->sb_agcount - 1) + 1;
585 	mp->m_agino_log = sbp->sb_inopblog + sbp->sb_agblklog;
586 	mp->m_litino = sbp->sb_inodesize -
587 		((uint)sizeof(xfs_dinode_core_t) + (uint)sizeof(xfs_agino_t));
588 	mp->m_blockmask = sbp->sb_blocksize - 1;
589 	mp->m_blockwsize = sbp->sb_blocksize >> XFS_WORDLOG;
590 	mp->m_blockwmask = mp->m_blockwsize - 1;
591 	INIT_LIST_HEAD(&mp->m_del_inodes);
592 
593 	/*
594 	 * Setup for attributes, in case they get created.
595 	 * This value is for inodes getting attributes for the first time,
596 	 * the per-inode value is for old attribute values.
597 	 */
598 	ASSERT(sbp->sb_inodesize >= 256 && sbp->sb_inodesize <= 2048);
599 	switch (sbp->sb_inodesize) {
600 	case 256:
601 		mp->m_attroffset = XFS_LITINO(mp) -
602 				   XFS_BMDR_SPACE_CALC(MINABTPTRS);
603 		break;
604 	case 512:
605 	case 1024:
606 	case 2048:
607 		mp->m_attroffset = XFS_BMDR_SPACE_CALC(6 * MINABTPTRS);
608 		break;
609 	default:
610 		ASSERT(0);
611 	}
612 	ASSERT(mp->m_attroffset < XFS_LITINO(mp));
613 
614 	for (i = 0; i < 2; i++) {
615 		mp->m_alloc_mxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
616 			xfs_alloc, i == 0);
617 		mp->m_alloc_mnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
618 			xfs_alloc, i == 0);
619 	}
620 	for (i = 0; i < 2; i++) {
621 		mp->m_bmap_dmxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
622 			xfs_bmbt, i == 0);
623 		mp->m_bmap_dmnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
624 			xfs_bmbt, i == 0);
625 	}
626 	for (i = 0; i < 2; i++) {
627 		mp->m_inobt_mxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
628 			xfs_inobt, i == 0);
629 		mp->m_inobt_mnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
630 			xfs_inobt, i == 0);
631 	}
632 
633 	mp->m_bsize = XFS_FSB_TO_BB(mp, 1);
634 	mp->m_ialloc_inos = (int)MAX((__uint16_t)XFS_INODES_PER_CHUNK,
635 					sbp->sb_inopblock);
636 	mp->m_ialloc_blks = mp->m_ialloc_inos >> sbp->sb_inopblog;
637 }
638 /*
639  * xfs_mountfs
640  *
641  * This function does the following on an initial mount of a file system:
642  *	- reads the superblock from disk and init the mount struct
643  *	- if we're a 32-bit kernel, do a size check on the superblock
644  *		so we don't mount terabyte filesystems
645  *	- init mount struct realtime fields
646  *	- allocate inode hash table for fs
647  *	- init directory manager
648  *	- perform recovery and init the log manager
649  */
650 int
651 xfs_mountfs(
652 	bhv_vfs_t	*vfsp,
653 	xfs_mount_t	*mp,
654 	int		mfsi_flags)
655 {
656 	xfs_buf_t	*bp;
657 	xfs_sb_t	*sbp = &(mp->m_sb);
658 	xfs_inode_t	*rip;
659 	bhv_vnode_t	*rvp = NULL;
660 	int		readio_log, writeio_log;
661 	xfs_daddr_t	d;
662 	__uint64_t	ret64;
663 	__int64_t	update_flags;
664 	uint		quotamount, quotaflags;
665 	int		agno;
666 	int		uuid_mounted = 0;
667 	int		error = 0;
668 
669 	if (mp->m_sb_bp == NULL) {
670 		if ((error = xfs_readsb(mp, mfsi_flags))) {
671 			return error;
672 		}
673 	}
674 	xfs_mount_common(mp, sbp);
675 
676 	/*
677 	 * Check if sb_agblocks is aligned at stripe boundary
678 	 * If sb_agblocks is NOT aligned turn off m_dalign since
679 	 * allocator alignment is within an ag, therefore ag has
680 	 * to be aligned at stripe boundary.
681 	 */
682 	update_flags = 0LL;
683 	if (mp->m_dalign && !(mfsi_flags & XFS_MFSI_SECOND)) {
684 		/*
685 		 * If stripe unit and stripe width are not multiples
686 		 * of the fs blocksize turn off alignment.
687 		 */
688 		if ((BBTOB(mp->m_dalign) & mp->m_blockmask) ||
689 		    (BBTOB(mp->m_swidth) & mp->m_blockmask)) {
690 			if (mp->m_flags & XFS_MOUNT_RETERR) {
691 				cmn_err(CE_WARN,
692 					"XFS: alignment check 1 failed");
693 				error = XFS_ERROR(EINVAL);
694 				goto error1;
695 			}
696 			mp->m_dalign = mp->m_swidth = 0;
697 		} else {
698 			/*
699 			 * Convert the stripe unit and width to FSBs.
700 			 */
701 			mp->m_dalign = XFS_BB_TO_FSBT(mp, mp->m_dalign);
702 			if (mp->m_dalign && (sbp->sb_agblocks % mp->m_dalign)) {
703 				if (mp->m_flags & XFS_MOUNT_RETERR) {
704 					error = XFS_ERROR(EINVAL);
705 					goto error1;
706 				}
707 				xfs_fs_cmn_err(CE_WARN, mp,
708 "stripe alignment turned off: sunit(%d)/swidth(%d) incompatible with agsize(%d)",
709 					mp->m_dalign, mp->m_swidth,
710 					sbp->sb_agblocks);
711 
712 				mp->m_dalign = 0;
713 				mp->m_swidth = 0;
714 			} else if (mp->m_dalign) {
715 				mp->m_swidth = XFS_BB_TO_FSBT(mp, mp->m_swidth);
716 			} else {
717 				if (mp->m_flags & XFS_MOUNT_RETERR) {
718 					xfs_fs_cmn_err(CE_WARN, mp,
719 "stripe alignment turned off: sunit(%d) less than bsize(%d)",
720                                         	mp->m_dalign,
721 						mp->m_blockmask +1);
722 					error = XFS_ERROR(EINVAL);
723 					goto error1;
724 				}
725 				mp->m_swidth = 0;
726 			}
727 		}
728 
729 		/*
730 		 * Update superblock with new values
731 		 * and log changes
732 		 */
733 		if (XFS_SB_VERSION_HASDALIGN(sbp)) {
734 			if (sbp->sb_unit != mp->m_dalign) {
735 				sbp->sb_unit = mp->m_dalign;
736 				update_flags |= XFS_SB_UNIT;
737 			}
738 			if (sbp->sb_width != mp->m_swidth) {
739 				sbp->sb_width = mp->m_swidth;
740 				update_flags |= XFS_SB_WIDTH;
741 			}
742 		}
743 	} else if ((mp->m_flags & XFS_MOUNT_NOALIGN) != XFS_MOUNT_NOALIGN &&
744 		    XFS_SB_VERSION_HASDALIGN(&mp->m_sb)) {
745 			mp->m_dalign = sbp->sb_unit;
746 			mp->m_swidth = sbp->sb_width;
747 	}
748 
749 	xfs_alloc_compute_maxlevels(mp);
750 	xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK);
751 	xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK);
752 	xfs_ialloc_compute_maxlevels(mp);
753 
754 	if (sbp->sb_imax_pct) {
755 		__uint64_t	icount;
756 
757 		/* Make sure the maximum inode count is a multiple of the
758 		 * units we allocate inodes in.
759 		 */
760 
761 		icount = sbp->sb_dblocks * sbp->sb_imax_pct;
762 		do_div(icount, 100);
763 		do_div(icount, mp->m_ialloc_blks);
764 		mp->m_maxicount = (icount * mp->m_ialloc_blks)  <<
765 				   sbp->sb_inopblog;
766 	} else
767 		mp->m_maxicount = 0;
768 
769 	mp->m_maxioffset = xfs_max_file_offset(sbp->sb_blocklog);
770 
771 	/*
772 	 * XFS uses the uuid from the superblock as the unique
773 	 * identifier for fsid.  We can not use the uuid from the volume
774 	 * since a single partition filesystem is identical to a single
775 	 * partition volume/filesystem.
776 	 */
777 	if ((mfsi_flags & XFS_MFSI_SECOND) == 0 &&
778 	    (mp->m_flags & XFS_MOUNT_NOUUID) == 0) {
779 		if (xfs_uuid_mount(mp)) {
780 			error = XFS_ERROR(EINVAL);
781 			goto error1;
782 		}
783 		uuid_mounted=1;
784 		ret64 = uuid_hash64(&sbp->sb_uuid);
785 		memcpy(&vfsp->vfs_fsid, &ret64, sizeof(ret64));
786 	}
787 
788 	/*
789 	 * Set the default minimum read and write sizes unless
790 	 * already specified in a mount option.
791 	 * We use smaller I/O sizes when the file system
792 	 * is being used for NFS service (wsync mount option).
793 	 */
794 	if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
795 		if (mp->m_flags & XFS_MOUNT_WSYNC) {
796 			readio_log = XFS_WSYNC_READIO_LOG;
797 			writeio_log = XFS_WSYNC_WRITEIO_LOG;
798 		} else {
799 			readio_log = XFS_READIO_LOG_LARGE;
800 			writeio_log = XFS_WRITEIO_LOG_LARGE;
801 		}
802 	} else {
803 		readio_log = mp->m_readio_log;
804 		writeio_log = mp->m_writeio_log;
805 	}
806 
807 	/*
808 	 * Set the number of readahead buffers to use based on
809 	 * physical memory size.
810 	 */
811 	if (xfs_physmem <= 4096)		/* <= 16MB */
812 		mp->m_nreadaheads = XFS_RW_NREADAHEAD_16MB;
813 	else if (xfs_physmem <= 8192)	/* <= 32MB */
814 		mp->m_nreadaheads = XFS_RW_NREADAHEAD_32MB;
815 	else
816 		mp->m_nreadaheads = XFS_RW_NREADAHEAD_K32;
817 	if (sbp->sb_blocklog > readio_log) {
818 		mp->m_readio_log = sbp->sb_blocklog;
819 	} else {
820 		mp->m_readio_log = readio_log;
821 	}
822 	mp->m_readio_blocks = 1 << (mp->m_readio_log - sbp->sb_blocklog);
823 	if (sbp->sb_blocklog > writeio_log) {
824 		mp->m_writeio_log = sbp->sb_blocklog;
825 	} else {
826 		mp->m_writeio_log = writeio_log;
827 	}
828 	mp->m_writeio_blocks = 1 << (mp->m_writeio_log - sbp->sb_blocklog);
829 
830 	/*
831 	 * Set the inode cluster size based on the physical memory
832 	 * size.  This may still be overridden by the file system
833 	 * block size if it is larger than the chosen cluster size.
834 	 */
835 	if (xfs_physmem <= btoc(32 * 1024 * 1024)) { /* <= 32 MB */
836 		mp->m_inode_cluster_size = XFS_INODE_SMALL_CLUSTER_SIZE;
837 	} else {
838 		mp->m_inode_cluster_size = XFS_INODE_BIG_CLUSTER_SIZE;
839 	}
840 	/*
841 	 * Set whether we're using inode alignment.
842 	 */
843 	if (XFS_SB_VERSION_HASALIGN(&mp->m_sb) &&
844 	    mp->m_sb.sb_inoalignmt >=
845 	    XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size))
846 		mp->m_inoalign_mask = mp->m_sb.sb_inoalignmt - 1;
847 	else
848 		mp->m_inoalign_mask = 0;
849 	/*
850 	 * If we are using stripe alignment, check whether
851 	 * the stripe unit is a multiple of the inode alignment
852 	 */
853 	if (mp->m_dalign && mp->m_inoalign_mask &&
854 	    !(mp->m_dalign & mp->m_inoalign_mask))
855 		mp->m_sinoalign = mp->m_dalign;
856 	else
857 		mp->m_sinoalign = 0;
858 	/*
859 	 * Check that the data (and log if separate) are an ok size.
860 	 */
861 	d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
862 	if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
863 		cmn_err(CE_WARN, "XFS: size check 1 failed");
864 		error = XFS_ERROR(E2BIG);
865 		goto error1;
866 	}
867 	error = xfs_read_buf(mp, mp->m_ddev_targp,
868 			     d - XFS_FSS_TO_BB(mp, 1),
869 			     XFS_FSS_TO_BB(mp, 1), 0, &bp);
870 	if (!error) {
871 		xfs_buf_relse(bp);
872 	} else {
873 		cmn_err(CE_WARN, "XFS: size check 2 failed");
874 		if (error == ENOSPC) {
875 			error = XFS_ERROR(E2BIG);
876 		}
877 		goto error1;
878 	}
879 
880 	if (((mfsi_flags & XFS_MFSI_CLIENT) == 0) &&
881 	    mp->m_logdev_targp != mp->m_ddev_targp) {
882 		d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
883 		if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
884 			cmn_err(CE_WARN, "XFS: size check 3 failed");
885 			error = XFS_ERROR(E2BIG);
886 			goto error1;
887 		}
888 		error = xfs_read_buf(mp, mp->m_logdev_targp,
889 				     d - XFS_FSB_TO_BB(mp, 1),
890 				     XFS_FSB_TO_BB(mp, 1), 0, &bp);
891 		if (!error) {
892 			xfs_buf_relse(bp);
893 		} else {
894 			cmn_err(CE_WARN, "XFS: size check 3 failed");
895 			if (error == ENOSPC) {
896 				error = XFS_ERROR(E2BIG);
897 			}
898 			goto error1;
899 		}
900 	}
901 
902 	/*
903 	 * Initialize realtime fields in the mount structure
904 	 */
905 	if ((error = xfs_rtmount_init(mp))) {
906 		cmn_err(CE_WARN, "XFS: RT mount failed");
907 		goto error1;
908 	}
909 
910 	/*
911 	 * For client case we are done now
912 	 */
913 	if (mfsi_flags & XFS_MFSI_CLIENT) {
914 		return 0;
915 	}
916 
917 	/*
918 	 *  Copies the low order bits of the timestamp and the randomly
919 	 *  set "sequence" number out of a UUID.
920 	 */
921 	uuid_getnodeuniq(&sbp->sb_uuid, mp->m_fixedfsid);
922 
923 	/*
924 	 *  The vfs structure needs to have a file system independent
925 	 *  way of checking for the invariant file system ID.  Since it
926 	 *  can't look at mount structures it has a pointer to the data
927 	 *  in the mount structure.
928 	 *
929 	 *  File systems that don't support user level file handles (i.e.
930 	 *  all of them except for XFS) will leave vfs_altfsid as NULL.
931 	 */
932 	vfsp->vfs_altfsid = (xfs_fsid_t *)mp->m_fixedfsid;
933 	mp->m_dmevmask = 0;	/* not persistent; set after each mount */
934 
935 	xfs_dir_mount(mp);
936 
937 	/*
938 	 * Initialize the attribute manager's entries.
939 	 */
940 	mp->m_attr_magicpct = (mp->m_sb.sb_blocksize * 37) / 100;
941 
942 	/*
943 	 * Initialize the precomputed transaction reservations values.
944 	 */
945 	xfs_trans_init(mp);
946 
947 	/*
948 	 * Allocate and initialize the inode hash table for this
949 	 * file system.
950 	 */
951 	xfs_ihash_init(mp);
952 	xfs_chash_init(mp);
953 
954 	/*
955 	 * Allocate and initialize the per-ag data.
956 	 */
957 	init_rwsem(&mp->m_peraglock);
958 	mp->m_perag =
959 		kmem_zalloc(sbp->sb_agcount * sizeof(xfs_perag_t), KM_SLEEP);
960 
961 	mp->m_maxagi = xfs_initialize_perag(vfsp, mp, sbp->sb_agcount);
962 
963 	/*
964 	 * log's mount-time initialization. Perform 1st part recovery if needed
965 	 */
966 	if (likely(sbp->sb_logblocks > 0)) {	/* check for volume case */
967 		error = xfs_log_mount(mp, mp->m_logdev_targp,
968 				      XFS_FSB_TO_DADDR(mp, sbp->sb_logstart),
969 				      XFS_FSB_TO_BB(mp, sbp->sb_logblocks));
970 		if (error) {
971 			cmn_err(CE_WARN, "XFS: log mount failed");
972 			goto error2;
973 		}
974 	} else {	/* No log has been defined */
975 		cmn_err(CE_WARN, "XFS: no log defined");
976 		XFS_ERROR_REPORT("xfs_mountfs_int(1)", XFS_ERRLEVEL_LOW, mp);
977 		error = XFS_ERROR(EFSCORRUPTED);
978 		goto error2;
979 	}
980 
981 	/*
982 	 * Get and sanity-check the root inode.
983 	 * Save the pointer to it in the mount structure.
984 	 */
985 	error = xfs_iget(mp, NULL, sbp->sb_rootino, 0, XFS_ILOCK_EXCL, &rip, 0);
986 	if (error) {
987 		cmn_err(CE_WARN, "XFS: failed to read root inode");
988 		goto error3;
989 	}
990 
991 	ASSERT(rip != NULL);
992 	rvp = XFS_ITOV(rip);
993 
994 	if (unlikely((rip->i_d.di_mode & S_IFMT) != S_IFDIR)) {
995 		cmn_err(CE_WARN, "XFS: corrupted root inode");
996 		cmn_err(CE_WARN, "Device %s - root %llu is not a directory",
997 			XFS_BUFTARG_NAME(mp->m_ddev_targp),
998 			(unsigned long long)rip->i_ino);
999 		xfs_iunlock(rip, XFS_ILOCK_EXCL);
1000 		XFS_ERROR_REPORT("xfs_mountfs_int(2)", XFS_ERRLEVEL_LOW,
1001 				 mp);
1002 		error = XFS_ERROR(EFSCORRUPTED);
1003 		goto error4;
1004 	}
1005 	mp->m_rootip = rip;	/* save it */
1006 
1007 	xfs_iunlock(rip, XFS_ILOCK_EXCL);
1008 
1009 	/*
1010 	 * Initialize realtime inode pointers in the mount structure
1011 	 */
1012 	if ((error = xfs_rtmount_inodes(mp))) {
1013 		/*
1014 		 * Free up the root inode.
1015 		 */
1016 		cmn_err(CE_WARN, "XFS: failed to read RT inodes");
1017 		goto error4;
1018 	}
1019 
1020 	/*
1021 	 * If fs is not mounted readonly, then update the superblock
1022 	 * unit and width changes.
1023 	 */
1024 	if (update_flags && !(vfsp->vfs_flag & VFS_RDONLY))
1025 		xfs_mount_log_sbunit(mp, update_flags);
1026 
1027 	/*
1028 	 * Initialise the XFS quota management subsystem for this mount
1029 	 */
1030 	if ((error = XFS_QM_INIT(mp, &quotamount, &quotaflags)))
1031 		goto error4;
1032 
1033 	/*
1034 	 * Finish recovering the file system.  This part needed to be
1035 	 * delayed until after the root and real-time bitmap inodes
1036 	 * were consistently read in.
1037 	 */
1038 	error = xfs_log_mount_finish(mp, mfsi_flags);
1039 	if (error) {
1040 		cmn_err(CE_WARN, "XFS: log mount finish failed");
1041 		goto error4;
1042 	}
1043 
1044 	/*
1045 	 * Complete the quota initialisation, post-log-replay component.
1046 	 */
1047 	if ((error = XFS_QM_MOUNT(mp, quotamount, quotaflags, mfsi_flags)))
1048 		goto error4;
1049 
1050 	return 0;
1051 
1052  error4:
1053 	/*
1054 	 * Free up the root inode.
1055 	 */
1056 	VN_RELE(rvp);
1057  error3:
1058 	xfs_log_unmount_dealloc(mp);
1059  error2:
1060 	xfs_ihash_free(mp);
1061 	xfs_chash_free(mp);
1062 	for (agno = 0; agno < sbp->sb_agcount; agno++)
1063 		if (mp->m_perag[agno].pagb_list)
1064 			kmem_free(mp->m_perag[agno].pagb_list,
1065 			  sizeof(xfs_perag_busy_t) * XFS_PAGB_NUM_SLOTS);
1066 	kmem_free(mp->m_perag, sbp->sb_agcount * sizeof(xfs_perag_t));
1067 	mp->m_perag = NULL;
1068 	/* FALLTHROUGH */
1069  error1:
1070 	if (uuid_mounted)
1071 		xfs_uuid_unmount(mp);
1072 	xfs_freesb(mp);
1073 	return error;
1074 }
1075 
1076 /*
1077  * xfs_unmountfs
1078  *
1079  * This flushes out the inodes,dquots and the superblock, unmounts the
1080  * log and makes sure that incore structures are freed.
1081  */
1082 int
1083 xfs_unmountfs(xfs_mount_t *mp, struct cred *cr)
1084 {
1085 	struct bhv_vfs	*vfsp = XFS_MTOVFS(mp);
1086 #if defined(DEBUG) || defined(INDUCE_IO_ERROR)
1087 	int64_t		fsid;
1088 #endif
1089 
1090 	xfs_iflush_all(mp);
1091 
1092 	XFS_QM_DQPURGEALL(mp, XFS_QMOPT_QUOTALL | XFS_QMOPT_UMOUNTING);
1093 
1094 	/*
1095 	 * Flush out the log synchronously so that we know for sure
1096 	 * that nothing is pinned.  This is important because bflush()
1097 	 * will skip pinned buffers.
1098 	 */
1099 	xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE | XFS_LOG_SYNC);
1100 
1101 	xfs_binval(mp->m_ddev_targp);
1102 	if (mp->m_rtdev_targp) {
1103 		xfs_binval(mp->m_rtdev_targp);
1104 	}
1105 
1106 	xfs_unmountfs_writesb(mp);
1107 
1108 	xfs_unmountfs_wait(mp); 		/* wait for async bufs */
1109 
1110 	xfs_log_unmount(mp);			/* Done! No more fs ops. */
1111 
1112 	xfs_freesb(mp);
1113 
1114 	/*
1115 	 * All inodes from this mount point should be freed.
1116 	 */
1117 	ASSERT(mp->m_inodes == NULL);
1118 
1119 	xfs_unmountfs_close(mp, cr);
1120 	if ((mp->m_flags & XFS_MOUNT_NOUUID) == 0)
1121 		xfs_uuid_unmount(mp);
1122 
1123 #if defined(DEBUG) || defined(INDUCE_IO_ERROR)
1124 	/*
1125 	 * clear all error tags on this filesystem
1126 	 */
1127 	memcpy(&fsid, &vfsp->vfs_fsid, sizeof(int64_t));
1128 	xfs_errortag_clearall_umount(fsid, mp->m_fsname, 0);
1129 #endif
1130 	XFS_IODONE(vfsp);
1131 	xfs_mount_free(mp, 1);
1132 	return 0;
1133 }
1134 
1135 void
1136 xfs_unmountfs_close(xfs_mount_t *mp, struct cred *cr)
1137 {
1138 	if (mp->m_logdev_targp != mp->m_ddev_targp)
1139 		xfs_free_buftarg(mp->m_logdev_targp, 1);
1140 	if (mp->m_rtdev_targp)
1141 		xfs_free_buftarg(mp->m_rtdev_targp, 1);
1142 	xfs_free_buftarg(mp->m_ddev_targp, 0);
1143 }
1144 
1145 STATIC void
1146 xfs_unmountfs_wait(xfs_mount_t *mp)
1147 {
1148 	if (mp->m_logdev_targp != mp->m_ddev_targp)
1149 		xfs_wait_buftarg(mp->m_logdev_targp);
1150 	if (mp->m_rtdev_targp)
1151 		xfs_wait_buftarg(mp->m_rtdev_targp);
1152 	xfs_wait_buftarg(mp->m_ddev_targp);
1153 }
1154 
1155 int
1156 xfs_unmountfs_writesb(xfs_mount_t *mp)
1157 {
1158 	xfs_buf_t	*sbp;
1159 	xfs_sb_t	*sb;
1160 	int		error = 0;
1161 
1162 	/*
1163 	 * skip superblock write if fs is read-only, or
1164 	 * if we are doing a forced umount.
1165 	 */
1166 	sbp = xfs_getsb(mp, 0);
1167 	if (!(XFS_MTOVFS(mp)->vfs_flag & VFS_RDONLY ||
1168 		XFS_FORCED_SHUTDOWN(mp))) {
1169 
1170 		xfs_icsb_sync_counters(mp);
1171 
1172 		/*
1173 		 * mark shared-readonly if desired
1174 		 */
1175 		sb = XFS_BUF_TO_SBP(sbp);
1176 		if (mp->m_mk_sharedro) {
1177 			if (!(sb->sb_flags & XFS_SBF_READONLY))
1178 				sb->sb_flags |= XFS_SBF_READONLY;
1179 			if (!XFS_SB_VERSION_HASSHARED(sb))
1180 				XFS_SB_VERSION_ADDSHARED(sb);
1181 			xfs_fs_cmn_err(CE_NOTE, mp,
1182 				"Unmounting, marking shared read-only");
1183 		}
1184 		XFS_BUF_UNDONE(sbp);
1185 		XFS_BUF_UNREAD(sbp);
1186 		XFS_BUF_UNDELAYWRITE(sbp);
1187 		XFS_BUF_WRITE(sbp);
1188 		XFS_BUF_UNASYNC(sbp);
1189 		ASSERT(XFS_BUF_TARGET(sbp) == mp->m_ddev_targp);
1190 		xfsbdstrat(mp, sbp);
1191 		/* Nevermind errors we might get here. */
1192 		error = xfs_iowait(sbp);
1193 		if (error)
1194 			xfs_ioerror_alert("xfs_unmountfs_writesb",
1195 					  mp, sbp, XFS_BUF_ADDR(sbp));
1196 		if (error && mp->m_mk_sharedro)
1197 			xfs_fs_cmn_err(CE_ALERT, mp, "Superblock write error detected while unmounting.  Filesystem may not be marked shared readonly");
1198 	}
1199 	xfs_buf_relse(sbp);
1200 	return error;
1201 }
1202 
1203 /*
1204  * xfs_mod_sb() can be used to copy arbitrary changes to the
1205  * in-core superblock into the superblock buffer to be logged.
1206  * It does not provide the higher level of locking that is
1207  * needed to protect the in-core superblock from concurrent
1208  * access.
1209  */
1210 void
1211 xfs_mod_sb(xfs_trans_t *tp, __int64_t fields)
1212 {
1213 	xfs_buf_t	*bp;
1214 	int		first;
1215 	int		last;
1216 	xfs_mount_t	*mp;
1217 	xfs_sb_t	*sbp;
1218 	xfs_sb_field_t	f;
1219 
1220 	ASSERT(fields);
1221 	if (!fields)
1222 		return;
1223 	mp = tp->t_mountp;
1224 	bp = xfs_trans_getsb(tp, mp, 0);
1225 	sbp = XFS_BUF_TO_SBP(bp);
1226 	first = sizeof(xfs_sb_t);
1227 	last = 0;
1228 
1229 	/* translate/copy */
1230 
1231 	xfs_xlatesb(XFS_BUF_PTR(bp), &(mp->m_sb), -1, fields);
1232 
1233 	/* find modified range */
1234 
1235 	f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
1236 	ASSERT((1LL << f) & XFS_SB_MOD_BITS);
1237 	first = xfs_sb_info[f].offset;
1238 
1239 	f = (xfs_sb_field_t)xfs_highbit64((__uint64_t)fields);
1240 	ASSERT((1LL << f) & XFS_SB_MOD_BITS);
1241 	last = xfs_sb_info[f + 1].offset - 1;
1242 
1243 	xfs_trans_log_buf(tp, bp, first, last);
1244 }
1245 
1246 /*
1247  * In order to avoid ENOSPC-related deadlock caused by
1248  * out-of-order locking of AGF buffer (PV 947395), we place
1249  * constraints on the relationship among actual allocations for
1250  * data blocks, freelist blocks, and potential file data bmap
1251  * btree blocks. However, these restrictions may result in no
1252  * actual space allocated for a delayed extent, for example, a data
1253  * block in a certain AG is allocated but there is no additional
1254  * block for the additional bmap btree block due to a split of the
1255  * bmap btree of the file. The result of this may lead to an
1256  * infinite loop in xfssyncd when the file gets flushed to disk and
1257  * all delayed extents need to be actually allocated. To get around
1258  * this, we explicitly set aside a few blocks which will not be
1259  * reserved in delayed allocation. Considering the minimum number of
1260  * needed freelist blocks is 4 fsbs, a potential split of file's bmap
1261  * btree requires 1 fsb, so we set the number of set-aside blocks to 8.
1262 */
1263 #define SET_ASIDE_BLOCKS 8
1264 
1265 /*
1266  * xfs_mod_incore_sb_unlocked() is a utility routine common used to apply
1267  * a delta to a specified field in the in-core superblock.  Simply
1268  * switch on the field indicated and apply the delta to that field.
1269  * Fields are not allowed to dip below zero, so if the delta would
1270  * do this do not apply it and return EINVAL.
1271  *
1272  * The SB_LOCK must be held when this routine is called.
1273  */
1274 int
1275 xfs_mod_incore_sb_unlocked(xfs_mount_t *mp, xfs_sb_field_t field,
1276 			int delta, int rsvd)
1277 {
1278 	int		scounter;	/* short counter for 32 bit fields */
1279 	long long	lcounter;	/* long counter for 64 bit fields */
1280 	long long	res_used, rem;
1281 
1282 	/*
1283 	 * With the in-core superblock spin lock held, switch
1284 	 * on the indicated field.  Apply the delta to the
1285 	 * proper field.  If the fields value would dip below
1286 	 * 0, then do not apply the delta and return EINVAL.
1287 	 */
1288 	switch (field) {
1289 	case XFS_SBS_ICOUNT:
1290 		lcounter = (long long)mp->m_sb.sb_icount;
1291 		lcounter += delta;
1292 		if (lcounter < 0) {
1293 			ASSERT(0);
1294 			return XFS_ERROR(EINVAL);
1295 		}
1296 		mp->m_sb.sb_icount = lcounter;
1297 		return 0;
1298 	case XFS_SBS_IFREE:
1299 		lcounter = (long long)mp->m_sb.sb_ifree;
1300 		lcounter += delta;
1301 		if (lcounter < 0) {
1302 			ASSERT(0);
1303 			return XFS_ERROR(EINVAL);
1304 		}
1305 		mp->m_sb.sb_ifree = lcounter;
1306 		return 0;
1307 	case XFS_SBS_FDBLOCKS:
1308 
1309 		lcounter = (long long)mp->m_sb.sb_fdblocks - SET_ASIDE_BLOCKS;
1310 		res_used = (long long)(mp->m_resblks - mp->m_resblks_avail);
1311 
1312 		if (delta > 0) {		/* Putting blocks back */
1313 			if (res_used > delta) {
1314 				mp->m_resblks_avail += delta;
1315 			} else {
1316 				rem = delta - res_used;
1317 				mp->m_resblks_avail = mp->m_resblks;
1318 				lcounter += rem;
1319 			}
1320 		} else {				/* Taking blocks away */
1321 
1322 			lcounter += delta;
1323 
1324 		/*
1325 		 * If were out of blocks, use any available reserved blocks if
1326 		 * were allowed to.
1327 		 */
1328 
1329 			if (lcounter < 0) {
1330 				if (rsvd) {
1331 					lcounter = (long long)mp->m_resblks_avail + delta;
1332 					if (lcounter < 0) {
1333 						return XFS_ERROR(ENOSPC);
1334 					}
1335 					mp->m_resblks_avail = lcounter;
1336 					return 0;
1337 				} else {	/* not reserved */
1338 					return XFS_ERROR(ENOSPC);
1339 				}
1340 			}
1341 		}
1342 
1343 		mp->m_sb.sb_fdblocks = lcounter + SET_ASIDE_BLOCKS;
1344 		return 0;
1345 	case XFS_SBS_FREXTENTS:
1346 		lcounter = (long long)mp->m_sb.sb_frextents;
1347 		lcounter += delta;
1348 		if (lcounter < 0) {
1349 			return XFS_ERROR(ENOSPC);
1350 		}
1351 		mp->m_sb.sb_frextents = lcounter;
1352 		return 0;
1353 	case XFS_SBS_DBLOCKS:
1354 		lcounter = (long long)mp->m_sb.sb_dblocks;
1355 		lcounter += delta;
1356 		if (lcounter < 0) {
1357 			ASSERT(0);
1358 			return XFS_ERROR(EINVAL);
1359 		}
1360 		mp->m_sb.sb_dblocks = lcounter;
1361 		return 0;
1362 	case XFS_SBS_AGCOUNT:
1363 		scounter = mp->m_sb.sb_agcount;
1364 		scounter += delta;
1365 		if (scounter < 0) {
1366 			ASSERT(0);
1367 			return XFS_ERROR(EINVAL);
1368 		}
1369 		mp->m_sb.sb_agcount = scounter;
1370 		return 0;
1371 	case XFS_SBS_IMAX_PCT:
1372 		scounter = mp->m_sb.sb_imax_pct;
1373 		scounter += delta;
1374 		if (scounter < 0) {
1375 			ASSERT(0);
1376 			return XFS_ERROR(EINVAL);
1377 		}
1378 		mp->m_sb.sb_imax_pct = scounter;
1379 		return 0;
1380 	case XFS_SBS_REXTSIZE:
1381 		scounter = mp->m_sb.sb_rextsize;
1382 		scounter += delta;
1383 		if (scounter < 0) {
1384 			ASSERT(0);
1385 			return XFS_ERROR(EINVAL);
1386 		}
1387 		mp->m_sb.sb_rextsize = scounter;
1388 		return 0;
1389 	case XFS_SBS_RBMBLOCKS:
1390 		scounter = mp->m_sb.sb_rbmblocks;
1391 		scounter += delta;
1392 		if (scounter < 0) {
1393 			ASSERT(0);
1394 			return XFS_ERROR(EINVAL);
1395 		}
1396 		mp->m_sb.sb_rbmblocks = scounter;
1397 		return 0;
1398 	case XFS_SBS_RBLOCKS:
1399 		lcounter = (long long)mp->m_sb.sb_rblocks;
1400 		lcounter += delta;
1401 		if (lcounter < 0) {
1402 			ASSERT(0);
1403 			return XFS_ERROR(EINVAL);
1404 		}
1405 		mp->m_sb.sb_rblocks = lcounter;
1406 		return 0;
1407 	case XFS_SBS_REXTENTS:
1408 		lcounter = (long long)mp->m_sb.sb_rextents;
1409 		lcounter += delta;
1410 		if (lcounter < 0) {
1411 			ASSERT(0);
1412 			return XFS_ERROR(EINVAL);
1413 		}
1414 		mp->m_sb.sb_rextents = lcounter;
1415 		return 0;
1416 	case XFS_SBS_REXTSLOG:
1417 		scounter = mp->m_sb.sb_rextslog;
1418 		scounter += delta;
1419 		if (scounter < 0) {
1420 			ASSERT(0);
1421 			return XFS_ERROR(EINVAL);
1422 		}
1423 		mp->m_sb.sb_rextslog = scounter;
1424 		return 0;
1425 	default:
1426 		ASSERT(0);
1427 		return XFS_ERROR(EINVAL);
1428 	}
1429 }
1430 
1431 /*
1432  * xfs_mod_incore_sb() is used to change a field in the in-core
1433  * superblock structure by the specified delta.  This modification
1434  * is protected by the SB_LOCK.  Just use the xfs_mod_incore_sb_unlocked()
1435  * routine to do the work.
1436  */
1437 int
1438 xfs_mod_incore_sb(xfs_mount_t *mp, xfs_sb_field_t field, int delta, int rsvd)
1439 {
1440 	unsigned long	s;
1441 	int	status;
1442 
1443 	/* check for per-cpu counters */
1444 	switch (field) {
1445 #ifdef HAVE_PERCPU_SB
1446 	case XFS_SBS_ICOUNT:
1447 	case XFS_SBS_IFREE:
1448 	case XFS_SBS_FDBLOCKS:
1449 		if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1450 			status = xfs_icsb_modify_counters(mp, field,
1451 							delta, rsvd);
1452 			break;
1453 		}
1454 		/* FALLTHROUGH */
1455 #endif
1456 	default:
1457 		s = XFS_SB_LOCK(mp);
1458 		status = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
1459 		XFS_SB_UNLOCK(mp, s);
1460 		break;
1461 	}
1462 
1463 	return status;
1464 }
1465 
1466 /*
1467  * xfs_mod_incore_sb_batch() is used to change more than one field
1468  * in the in-core superblock structure at a time.  This modification
1469  * is protected by a lock internal to this module.  The fields and
1470  * changes to those fields are specified in the array of xfs_mod_sb
1471  * structures passed in.
1472  *
1473  * Either all of the specified deltas will be applied or none of
1474  * them will.  If any modified field dips below 0, then all modifications
1475  * will be backed out and EINVAL will be returned.
1476  */
1477 int
1478 xfs_mod_incore_sb_batch(xfs_mount_t *mp, xfs_mod_sb_t *msb, uint nmsb, int rsvd)
1479 {
1480 	unsigned long	s;
1481 	int		status=0;
1482 	xfs_mod_sb_t	*msbp;
1483 
1484 	/*
1485 	 * Loop through the array of mod structures and apply each
1486 	 * individually.  If any fail, then back out all those
1487 	 * which have already been applied.  Do all of this within
1488 	 * the scope of the SB_LOCK so that all of the changes will
1489 	 * be atomic.
1490 	 */
1491 	s = XFS_SB_LOCK(mp);
1492 	msbp = &msb[0];
1493 	for (msbp = &msbp[0]; msbp < (msb + nmsb); msbp++) {
1494 		/*
1495 		 * Apply the delta at index n.  If it fails, break
1496 		 * from the loop so we'll fall into the undo loop
1497 		 * below.
1498 		 */
1499 		switch (msbp->msb_field) {
1500 #ifdef HAVE_PERCPU_SB
1501 		case XFS_SBS_ICOUNT:
1502 		case XFS_SBS_IFREE:
1503 		case XFS_SBS_FDBLOCKS:
1504 			if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1505 				status = xfs_icsb_modify_counters_locked(mp,
1506 							msbp->msb_field,
1507 							msbp->msb_delta, rsvd);
1508 				break;
1509 			}
1510 			/* FALLTHROUGH */
1511 #endif
1512 		default:
1513 			status = xfs_mod_incore_sb_unlocked(mp,
1514 						msbp->msb_field,
1515 						msbp->msb_delta, rsvd);
1516 			break;
1517 		}
1518 
1519 		if (status != 0) {
1520 			break;
1521 		}
1522 	}
1523 
1524 	/*
1525 	 * If we didn't complete the loop above, then back out
1526 	 * any changes made to the superblock.  If you add code
1527 	 * between the loop above and here, make sure that you
1528 	 * preserve the value of status. Loop back until
1529 	 * we step below the beginning of the array.  Make sure
1530 	 * we don't touch anything back there.
1531 	 */
1532 	if (status != 0) {
1533 		msbp--;
1534 		while (msbp >= msb) {
1535 			switch (msbp->msb_field) {
1536 #ifdef HAVE_PERCPU_SB
1537 			case XFS_SBS_ICOUNT:
1538 			case XFS_SBS_IFREE:
1539 			case XFS_SBS_FDBLOCKS:
1540 				if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1541 					status =
1542 					    xfs_icsb_modify_counters_locked(mp,
1543 							msbp->msb_field,
1544 							-(msbp->msb_delta),
1545 							rsvd);
1546 					break;
1547 				}
1548 				/* FALLTHROUGH */
1549 #endif
1550 			default:
1551 				status = xfs_mod_incore_sb_unlocked(mp,
1552 							msbp->msb_field,
1553 							-(msbp->msb_delta),
1554 							rsvd);
1555 				break;
1556 			}
1557 			ASSERT(status == 0);
1558 			msbp--;
1559 		}
1560 	}
1561 	XFS_SB_UNLOCK(mp, s);
1562 	return status;
1563 }
1564 
1565 /*
1566  * xfs_getsb() is called to obtain the buffer for the superblock.
1567  * The buffer is returned locked and read in from disk.
1568  * The buffer should be released with a call to xfs_brelse().
1569  *
1570  * If the flags parameter is BUF_TRYLOCK, then we'll only return
1571  * the superblock buffer if it can be locked without sleeping.
1572  * If it can't then we'll return NULL.
1573  */
1574 xfs_buf_t *
1575 xfs_getsb(
1576 	xfs_mount_t	*mp,
1577 	int		flags)
1578 {
1579 	xfs_buf_t	*bp;
1580 
1581 	ASSERT(mp->m_sb_bp != NULL);
1582 	bp = mp->m_sb_bp;
1583 	if (flags & XFS_BUF_TRYLOCK) {
1584 		if (!XFS_BUF_CPSEMA(bp)) {
1585 			return NULL;
1586 		}
1587 	} else {
1588 		XFS_BUF_PSEMA(bp, PRIBIO);
1589 	}
1590 	XFS_BUF_HOLD(bp);
1591 	ASSERT(XFS_BUF_ISDONE(bp));
1592 	return bp;
1593 }
1594 
1595 /*
1596  * Used to free the superblock along various error paths.
1597  */
1598 void
1599 xfs_freesb(
1600 	xfs_mount_t	*mp)
1601 {
1602 	xfs_buf_t	*bp;
1603 
1604 	/*
1605 	 * Use xfs_getsb() so that the buffer will be locked
1606 	 * when we call xfs_buf_relse().
1607 	 */
1608 	bp = xfs_getsb(mp, 0);
1609 	XFS_BUF_UNMANAGE(bp);
1610 	xfs_buf_relse(bp);
1611 	mp->m_sb_bp = NULL;
1612 }
1613 
1614 /*
1615  * See if the UUID is unique among mounted XFS filesystems.
1616  * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
1617  */
1618 STATIC int
1619 xfs_uuid_mount(
1620 	xfs_mount_t	*mp)
1621 {
1622 	if (uuid_is_nil(&mp->m_sb.sb_uuid)) {
1623 		cmn_err(CE_WARN,
1624 			"XFS: Filesystem %s has nil UUID - can't mount",
1625 			mp->m_fsname);
1626 		return -1;
1627 	}
1628 	if (!uuid_table_insert(&mp->m_sb.sb_uuid)) {
1629 		cmn_err(CE_WARN,
1630 			"XFS: Filesystem %s has duplicate UUID - can't mount",
1631 			mp->m_fsname);
1632 		return -1;
1633 	}
1634 	return 0;
1635 }
1636 
1637 /*
1638  * Remove filesystem from the UUID table.
1639  */
1640 STATIC void
1641 xfs_uuid_unmount(
1642 	xfs_mount_t	*mp)
1643 {
1644 	uuid_table_remove(&mp->m_sb.sb_uuid);
1645 }
1646 
1647 /*
1648  * Used to log changes to the superblock unit and width fields which could
1649  * be altered by the mount options. Only the first superblock is updated.
1650  */
1651 STATIC void
1652 xfs_mount_log_sbunit(
1653 	xfs_mount_t	*mp,
1654 	__int64_t	fields)
1655 {
1656 	xfs_trans_t	*tp;
1657 
1658 	ASSERT(fields & (XFS_SB_UNIT|XFS_SB_WIDTH|XFS_SB_UUID));
1659 
1660 	tp = xfs_trans_alloc(mp, XFS_TRANS_SB_UNIT);
1661 	if (xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0,
1662 				XFS_DEFAULT_LOG_COUNT)) {
1663 		xfs_trans_cancel(tp, 0);
1664 		return;
1665 	}
1666 	xfs_mod_sb(tp, fields);
1667 	xfs_trans_commit(tp, 0, NULL);
1668 }
1669 
1670 
1671 #ifdef HAVE_PERCPU_SB
1672 /*
1673  * Per-cpu incore superblock counters
1674  *
1675  * Simple concept, difficult implementation
1676  *
1677  * Basically, replace the incore superblock counters with a distributed per cpu
1678  * counter for contended fields (e.g.  free block count).
1679  *
1680  * Difficulties arise in that the incore sb is used for ENOSPC checking, and
1681  * hence needs to be accurately read when we are running low on space. Hence
1682  * there is a method to enable and disable the per-cpu counters based on how
1683  * much "stuff" is available in them.
1684  *
1685  * Basically, a counter is enabled if there is enough free resource to justify
1686  * running a per-cpu fast-path. If the per-cpu counter runs out (i.e. a local
1687  * ENOSPC), then we disable the counters to synchronise all callers and
1688  * re-distribute the available resources.
1689  *
1690  * If, once we redistributed the available resources, we still get a failure,
1691  * we disable the per-cpu counter and go through the slow path.
1692  *
1693  * The slow path is the current xfs_mod_incore_sb() function.  This means that
1694  * when we disable a per-cpu counter, we need to drain it's resources back to
1695  * the global superblock. We do this after disabling the counter to prevent
1696  * more threads from queueing up on the counter.
1697  *
1698  * Essentially, this means that we still need a lock in the fast path to enable
1699  * synchronisation between the global counters and the per-cpu counters. This
1700  * is not a problem because the lock will be local to a CPU almost all the time
1701  * and have little contention except when we get to ENOSPC conditions.
1702  *
1703  * Basically, this lock becomes a barrier that enables us to lock out the fast
1704  * path while we do things like enabling and disabling counters and
1705  * synchronising the counters.
1706  *
1707  * Locking rules:
1708  *
1709  * 	1. XFS_SB_LOCK() before picking up per-cpu locks
1710  * 	2. per-cpu locks always picked up via for_each_online_cpu() order
1711  * 	3. accurate counter sync requires XFS_SB_LOCK + per cpu locks
1712  * 	4. modifying per-cpu counters requires holding per-cpu lock
1713  * 	5. modifying global counters requires holding XFS_SB_LOCK
1714  *	6. enabling or disabling a counter requires holding the XFS_SB_LOCK
1715  *	   and _none_ of the per-cpu locks.
1716  *
1717  * Disabled counters are only ever re-enabled by a balance operation
1718  * that results in more free resources per CPU than a given threshold.
1719  * To ensure counters don't remain disabled, they are rebalanced when
1720  * the global resource goes above a higher threshold (i.e. some hysteresis
1721  * is present to prevent thrashing).
1722  */
1723 
1724 /*
1725  * hot-plug CPU notifier support.
1726  *
1727  * We cannot use the hotcpu_register() function because it does
1728  * not allow notifier instances. We need a notifier per filesystem
1729  * as we need to be able to identify the filesystem to balance
1730  * the counters out. This is achieved by having a notifier block
1731  * embedded in the xfs_mount_t and doing pointer magic to get the
1732  * mount pointer from the notifier block address.
1733  */
1734 STATIC int
1735 xfs_icsb_cpu_notify(
1736 	struct notifier_block *nfb,
1737 	unsigned long action,
1738 	void *hcpu)
1739 {
1740 	xfs_icsb_cnts_t *cntp;
1741 	xfs_mount_t	*mp;
1742 	int		s;
1743 
1744 	mp = (xfs_mount_t *)container_of(nfb, xfs_mount_t, m_icsb_notifier);
1745 	cntp = (xfs_icsb_cnts_t *)
1746 			per_cpu_ptr(mp->m_sb_cnts, (unsigned long)hcpu);
1747 	switch (action) {
1748 	case CPU_UP_PREPARE:
1749 		/* Easy Case - initialize the area and locks, and
1750 		 * then rebalance when online does everything else for us. */
1751 		memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
1752 		break;
1753 	case CPU_ONLINE:
1754 		xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0);
1755 		xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0);
1756 		xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0);
1757 		break;
1758 	case CPU_DEAD:
1759 		/* Disable all the counters, then fold the dead cpu's
1760 		 * count into the total on the global superblock and
1761 		 * re-enable the counters. */
1762 		s = XFS_SB_LOCK(mp);
1763 		xfs_icsb_disable_counter(mp, XFS_SBS_ICOUNT);
1764 		xfs_icsb_disable_counter(mp, XFS_SBS_IFREE);
1765 		xfs_icsb_disable_counter(mp, XFS_SBS_FDBLOCKS);
1766 
1767 		mp->m_sb.sb_icount += cntp->icsb_icount;
1768 		mp->m_sb.sb_ifree += cntp->icsb_ifree;
1769 		mp->m_sb.sb_fdblocks += cntp->icsb_fdblocks;
1770 
1771 		memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
1772 
1773 		xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, XFS_ICSB_SB_LOCKED);
1774 		xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, XFS_ICSB_SB_LOCKED);
1775 		xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, XFS_ICSB_SB_LOCKED);
1776 		XFS_SB_UNLOCK(mp, s);
1777 		break;
1778 	}
1779 
1780 	return NOTIFY_OK;
1781 }
1782 
1783 int
1784 xfs_icsb_init_counters(
1785 	xfs_mount_t	*mp)
1786 {
1787 	xfs_icsb_cnts_t *cntp;
1788 	int		i;
1789 
1790 	mp->m_sb_cnts = alloc_percpu(xfs_icsb_cnts_t);
1791 	if (mp->m_sb_cnts == NULL)
1792 		return -ENOMEM;
1793 
1794 	mp->m_icsb_notifier.notifier_call = xfs_icsb_cpu_notify;
1795 	mp->m_icsb_notifier.priority = 0;
1796 	register_cpu_notifier(&mp->m_icsb_notifier);
1797 
1798 	for_each_online_cpu(i) {
1799 		cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
1800 		memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
1801 	}
1802 	/*
1803 	 * start with all counters disabled so that the
1804 	 * initial balance kicks us off correctly
1805 	 */
1806 	mp->m_icsb_counters = -1;
1807 	return 0;
1808 }
1809 
1810 STATIC void
1811 xfs_icsb_destroy_counters(
1812 	xfs_mount_t	*mp)
1813 {
1814 	if (mp->m_sb_cnts) {
1815 		unregister_cpu_notifier(&mp->m_icsb_notifier);
1816 		free_percpu(mp->m_sb_cnts);
1817 	}
1818 }
1819 
1820 STATIC inline void
1821 xfs_icsb_lock_cntr(
1822 	xfs_icsb_cnts_t	*icsbp)
1823 {
1824 	while (test_and_set_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags)) {
1825 		ndelay(1000);
1826 	}
1827 }
1828 
1829 STATIC inline void
1830 xfs_icsb_unlock_cntr(
1831 	xfs_icsb_cnts_t	*icsbp)
1832 {
1833 	clear_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags);
1834 }
1835 
1836 
1837 STATIC inline void
1838 xfs_icsb_lock_all_counters(
1839 	xfs_mount_t	*mp)
1840 {
1841 	xfs_icsb_cnts_t *cntp;
1842 	int		i;
1843 
1844 	for_each_online_cpu(i) {
1845 		cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
1846 		xfs_icsb_lock_cntr(cntp);
1847 	}
1848 }
1849 
1850 STATIC inline void
1851 xfs_icsb_unlock_all_counters(
1852 	xfs_mount_t	*mp)
1853 {
1854 	xfs_icsb_cnts_t *cntp;
1855 	int		i;
1856 
1857 	for_each_online_cpu(i) {
1858 		cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
1859 		xfs_icsb_unlock_cntr(cntp);
1860 	}
1861 }
1862 
1863 STATIC void
1864 xfs_icsb_count(
1865 	xfs_mount_t	*mp,
1866 	xfs_icsb_cnts_t	*cnt,
1867 	int		flags)
1868 {
1869 	xfs_icsb_cnts_t *cntp;
1870 	int		i;
1871 
1872 	memset(cnt, 0, sizeof(xfs_icsb_cnts_t));
1873 
1874 	if (!(flags & XFS_ICSB_LAZY_COUNT))
1875 		xfs_icsb_lock_all_counters(mp);
1876 
1877 	for_each_online_cpu(i) {
1878 		cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
1879 		cnt->icsb_icount += cntp->icsb_icount;
1880 		cnt->icsb_ifree += cntp->icsb_ifree;
1881 		cnt->icsb_fdblocks += cntp->icsb_fdblocks;
1882 	}
1883 
1884 	if (!(flags & XFS_ICSB_LAZY_COUNT))
1885 		xfs_icsb_unlock_all_counters(mp);
1886 }
1887 
1888 STATIC int
1889 xfs_icsb_counter_disabled(
1890 	xfs_mount_t	*mp,
1891 	xfs_sb_field_t	field)
1892 {
1893 	ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
1894 	return test_bit(field, &mp->m_icsb_counters);
1895 }
1896 
1897 STATIC int
1898 xfs_icsb_disable_counter(
1899 	xfs_mount_t	*mp,
1900 	xfs_sb_field_t	field)
1901 {
1902 	xfs_icsb_cnts_t	cnt;
1903 
1904 	ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
1905 
1906 	xfs_icsb_lock_all_counters(mp);
1907 	if (!test_and_set_bit(field, &mp->m_icsb_counters)) {
1908 		/* drain back to superblock */
1909 
1910 		xfs_icsb_count(mp, &cnt, XFS_ICSB_SB_LOCKED|XFS_ICSB_LAZY_COUNT);
1911 		switch(field) {
1912 		case XFS_SBS_ICOUNT:
1913 			mp->m_sb.sb_icount = cnt.icsb_icount;
1914 			break;
1915 		case XFS_SBS_IFREE:
1916 			mp->m_sb.sb_ifree = cnt.icsb_ifree;
1917 			break;
1918 		case XFS_SBS_FDBLOCKS:
1919 			mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
1920 			break;
1921 		default:
1922 			BUG();
1923 		}
1924 	}
1925 
1926 	xfs_icsb_unlock_all_counters(mp);
1927 
1928 	return 0;
1929 }
1930 
1931 STATIC void
1932 xfs_icsb_enable_counter(
1933 	xfs_mount_t	*mp,
1934 	xfs_sb_field_t	field,
1935 	uint64_t	count,
1936 	uint64_t	resid)
1937 {
1938 	xfs_icsb_cnts_t	*cntp;
1939 	int		i;
1940 
1941 	ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
1942 
1943 	xfs_icsb_lock_all_counters(mp);
1944 	for_each_online_cpu(i) {
1945 		cntp = per_cpu_ptr(mp->m_sb_cnts, i);
1946 		switch (field) {
1947 		case XFS_SBS_ICOUNT:
1948 			cntp->icsb_icount = count + resid;
1949 			break;
1950 		case XFS_SBS_IFREE:
1951 			cntp->icsb_ifree = count + resid;
1952 			break;
1953 		case XFS_SBS_FDBLOCKS:
1954 			cntp->icsb_fdblocks = count + resid;
1955 			break;
1956 		default:
1957 			BUG();
1958 			break;
1959 		}
1960 		resid = 0;
1961 	}
1962 	clear_bit(field, &mp->m_icsb_counters);
1963 	xfs_icsb_unlock_all_counters(mp);
1964 }
1965 
1966 STATIC void
1967 xfs_icsb_sync_counters_int(
1968 	xfs_mount_t	*mp,
1969 	int		flags)
1970 {
1971 	xfs_icsb_cnts_t	cnt;
1972 	int		s;
1973 
1974 	/* Pass 1: lock all counters */
1975 	if ((flags & XFS_ICSB_SB_LOCKED) == 0)
1976 		s = XFS_SB_LOCK(mp);
1977 
1978 	xfs_icsb_count(mp, &cnt, flags);
1979 
1980 	/* Step 3: update mp->m_sb fields */
1981 	if (!xfs_icsb_counter_disabled(mp, XFS_SBS_ICOUNT))
1982 		mp->m_sb.sb_icount = cnt.icsb_icount;
1983 	if (!xfs_icsb_counter_disabled(mp, XFS_SBS_IFREE))
1984 		mp->m_sb.sb_ifree = cnt.icsb_ifree;
1985 	if (!xfs_icsb_counter_disabled(mp, XFS_SBS_FDBLOCKS))
1986 		mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
1987 
1988 	if ((flags & XFS_ICSB_SB_LOCKED) == 0)
1989 		XFS_SB_UNLOCK(mp, s);
1990 }
1991 
1992 /*
1993  * Accurate update of per-cpu counters to incore superblock
1994  */
1995 STATIC void
1996 xfs_icsb_sync_counters(
1997 	xfs_mount_t	*mp)
1998 {
1999 	xfs_icsb_sync_counters_int(mp, 0);
2000 }
2001 
2002 /*
2003  * lazy addition used for things like df, background sb syncs, etc
2004  */
2005 void
2006 xfs_icsb_sync_counters_lazy(
2007 	xfs_mount_t	*mp)
2008 {
2009 	xfs_icsb_sync_counters_int(mp, XFS_ICSB_LAZY_COUNT);
2010 }
2011 
2012 /*
2013  * Balance and enable/disable counters as necessary.
2014  *
2015  * Thresholds for re-enabling counters are somewhat magic.
2016  * inode counts are chosen to be the same number as single
2017  * on disk allocation chunk per CPU, and free blocks is
2018  * something far enough zero that we aren't going thrash
2019  * when we get near ENOSPC.
2020  */
2021 #define XFS_ICSB_INO_CNTR_REENABLE	64
2022 #define XFS_ICSB_FDBLK_CNTR_REENABLE	512
2023 STATIC void
2024 xfs_icsb_balance_counter(
2025 	xfs_mount_t	*mp,
2026 	xfs_sb_field_t  field,
2027 	int		flags)
2028 {
2029 	uint64_t	count, resid = 0;
2030 	int		weight = num_online_cpus();
2031 	int		s;
2032 
2033 	if (!(flags & XFS_ICSB_SB_LOCKED))
2034 		s = XFS_SB_LOCK(mp);
2035 
2036 	/* disable counter and sync counter */
2037 	xfs_icsb_disable_counter(mp, field);
2038 
2039 	/* update counters  - first CPU gets residual*/
2040 	switch (field) {
2041 	case XFS_SBS_ICOUNT:
2042 		count = mp->m_sb.sb_icount;
2043 		resid = do_div(count, weight);
2044 		if (count < XFS_ICSB_INO_CNTR_REENABLE)
2045 			goto out;
2046 		break;
2047 	case XFS_SBS_IFREE:
2048 		count = mp->m_sb.sb_ifree;
2049 		resid = do_div(count, weight);
2050 		if (count < XFS_ICSB_INO_CNTR_REENABLE)
2051 			goto out;
2052 		break;
2053 	case XFS_SBS_FDBLOCKS:
2054 		count = mp->m_sb.sb_fdblocks;
2055 		resid = do_div(count, weight);
2056 		if (count < XFS_ICSB_FDBLK_CNTR_REENABLE)
2057 			goto out;
2058 		break;
2059 	default:
2060 		BUG();
2061 		break;
2062 	}
2063 
2064 	xfs_icsb_enable_counter(mp, field, count, resid);
2065 out:
2066 	if (!(flags & XFS_ICSB_SB_LOCKED))
2067 		XFS_SB_UNLOCK(mp, s);
2068 }
2069 
2070 STATIC int
2071 xfs_icsb_modify_counters_int(
2072 	xfs_mount_t	*mp,
2073 	xfs_sb_field_t	field,
2074 	int		delta,
2075 	int		rsvd,
2076 	int		flags)
2077 {
2078 	xfs_icsb_cnts_t	*icsbp;
2079 	long long	lcounter;	/* long counter for 64 bit fields */
2080 	int		cpu, s, locked = 0;
2081 	int		ret = 0, balance_done = 0;
2082 
2083 again:
2084 	cpu = get_cpu();
2085 	icsbp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, cpu),
2086 	xfs_icsb_lock_cntr(icsbp);
2087 	if (unlikely(xfs_icsb_counter_disabled(mp, field)))
2088 		goto slow_path;
2089 
2090 	switch (field) {
2091 	case XFS_SBS_ICOUNT:
2092 		lcounter = icsbp->icsb_icount;
2093 		lcounter += delta;
2094 		if (unlikely(lcounter < 0))
2095 			goto slow_path;
2096 		icsbp->icsb_icount = lcounter;
2097 		break;
2098 
2099 	case XFS_SBS_IFREE:
2100 		lcounter = icsbp->icsb_ifree;
2101 		lcounter += delta;
2102 		if (unlikely(lcounter < 0))
2103 			goto slow_path;
2104 		icsbp->icsb_ifree = lcounter;
2105 		break;
2106 
2107 	case XFS_SBS_FDBLOCKS:
2108 		BUG_ON((mp->m_resblks - mp->m_resblks_avail) != 0);
2109 
2110 		lcounter = icsbp->icsb_fdblocks;
2111 		lcounter += delta;
2112 		if (unlikely(lcounter < 0))
2113 			goto slow_path;
2114 		icsbp->icsb_fdblocks = lcounter;
2115 		break;
2116 	default:
2117 		BUG();
2118 		break;
2119 	}
2120 	xfs_icsb_unlock_cntr(icsbp);
2121 	put_cpu();
2122 	if (locked)
2123 		XFS_SB_UNLOCK(mp, s);
2124 	return 0;
2125 
2126 	/*
2127 	 * The slow path needs to be run with the SBLOCK
2128 	 * held so that we prevent other threads from
2129 	 * attempting to run this path at the same time.
2130 	 * this provides exclusion for the balancing code,
2131 	 * and exclusive fallback if the balance does not
2132 	 * provide enough resources to continue in an unlocked
2133 	 * manner.
2134 	 */
2135 slow_path:
2136 	xfs_icsb_unlock_cntr(icsbp);
2137 	put_cpu();
2138 
2139 	/* need to hold superblock incase we need
2140 	 * to disable a counter */
2141 	if (!(flags & XFS_ICSB_SB_LOCKED)) {
2142 		s = XFS_SB_LOCK(mp);
2143 		locked = 1;
2144 		flags |= XFS_ICSB_SB_LOCKED;
2145 	}
2146 	if (!balance_done) {
2147 		xfs_icsb_balance_counter(mp, field, flags);
2148 		balance_done = 1;
2149 		goto again;
2150 	} else {
2151 		/*
2152 		 * we might not have enough on this local
2153 		 * cpu to allocate for a bulk request.
2154 		 * We need to drain this field from all CPUs
2155 		 * and disable the counter fastpath
2156 		 */
2157 		xfs_icsb_disable_counter(mp, field);
2158 	}
2159 
2160 	ret = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
2161 
2162 	if (locked)
2163 		XFS_SB_UNLOCK(mp, s);
2164 	return ret;
2165 }
2166 
2167 STATIC int
2168 xfs_icsb_modify_counters(
2169 	xfs_mount_t	*mp,
2170 	xfs_sb_field_t	field,
2171 	int		delta,
2172 	int		rsvd)
2173 {
2174 	return xfs_icsb_modify_counters_int(mp, field, delta, rsvd, 0);
2175 }
2176 
2177 /*
2178  * Called when superblock is already locked
2179  */
2180 STATIC int
2181 xfs_icsb_modify_counters_locked(
2182 	xfs_mount_t	*mp,
2183 	xfs_sb_field_t	field,
2184 	int		delta,
2185 	int		rsvd)
2186 {
2187 	return xfs_icsb_modify_counters_int(mp, field, delta,
2188 						rsvd, XFS_ICSB_SB_LOCKED);
2189 }
2190 #endif
2191