[XFS] Ensure "both" features2 slots are consistent
[sfrench/cifs-2.6.git] / fs / xfs / xfs_mount.c
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_sb(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,
56                                                 int, int);
57 STATIC void     xfs_icsb_sync_counters(xfs_mount_t *);
58 STATIC int      xfs_icsb_modify_counters(xfs_mount_t *, xfs_sb_field_t,
59                                                 int64_t, int);
60 STATIC int      xfs_icsb_disable_counter(xfs_mount_t *, xfs_sb_field_t);
61
62 #else
63
64 #define xfs_icsb_destroy_counters(mp)                   do { } while (0)
65 #define xfs_icsb_balance_counter(mp, a, b, c)           do { } while (0)
66 #define xfs_icsb_sync_counters(mp)                      do { } while (0)
67 #define xfs_icsb_modify_counters(mp, a, b, c)           do { } while (0)
68
69 #endif
70
71 static const struct {
72         short offset;
73         short type;     /* 0 = integer
74                          * 1 = binary / string (no translation)
75                          */
76 } xfs_sb_info[] = {
77     { offsetof(xfs_sb_t, sb_magicnum),   0 },
78     { offsetof(xfs_sb_t, sb_blocksize),  0 },
79     { offsetof(xfs_sb_t, sb_dblocks),    0 },
80     { offsetof(xfs_sb_t, sb_rblocks),    0 },
81     { offsetof(xfs_sb_t, sb_rextents),   0 },
82     { offsetof(xfs_sb_t, sb_uuid),       1 },
83     { offsetof(xfs_sb_t, sb_logstart),   0 },
84     { offsetof(xfs_sb_t, sb_rootino),    0 },
85     { offsetof(xfs_sb_t, sb_rbmino),     0 },
86     { offsetof(xfs_sb_t, sb_rsumino),    0 },
87     { offsetof(xfs_sb_t, sb_rextsize),   0 },
88     { offsetof(xfs_sb_t, sb_agblocks),   0 },
89     { offsetof(xfs_sb_t, sb_agcount),    0 },
90     { offsetof(xfs_sb_t, sb_rbmblocks),  0 },
91     { offsetof(xfs_sb_t, sb_logblocks),  0 },
92     { offsetof(xfs_sb_t, sb_versionnum), 0 },
93     { offsetof(xfs_sb_t, sb_sectsize),   0 },
94     { offsetof(xfs_sb_t, sb_inodesize),  0 },
95     { offsetof(xfs_sb_t, sb_inopblock),  0 },
96     { offsetof(xfs_sb_t, sb_fname[0]),   1 },
97     { offsetof(xfs_sb_t, sb_blocklog),   0 },
98     { offsetof(xfs_sb_t, sb_sectlog),    0 },
99     { offsetof(xfs_sb_t, sb_inodelog),   0 },
100     { offsetof(xfs_sb_t, sb_inopblog),   0 },
101     { offsetof(xfs_sb_t, sb_agblklog),   0 },
102     { offsetof(xfs_sb_t, sb_rextslog),   0 },
103     { offsetof(xfs_sb_t, sb_inprogress), 0 },
104     { offsetof(xfs_sb_t, sb_imax_pct),   0 },
105     { offsetof(xfs_sb_t, sb_icount),     0 },
106     { offsetof(xfs_sb_t, sb_ifree),      0 },
107     { offsetof(xfs_sb_t, sb_fdblocks),   0 },
108     { offsetof(xfs_sb_t, sb_frextents),  0 },
109     { offsetof(xfs_sb_t, sb_uquotino),   0 },
110     { offsetof(xfs_sb_t, sb_gquotino),   0 },
111     { offsetof(xfs_sb_t, sb_qflags),     0 },
112     { offsetof(xfs_sb_t, sb_flags),      0 },
113     { offsetof(xfs_sb_t, sb_shared_vn),  0 },
114     { offsetof(xfs_sb_t, sb_inoalignmt), 0 },
115     { offsetof(xfs_sb_t, sb_unit),       0 },
116     { offsetof(xfs_sb_t, sb_width),      0 },
117     { offsetof(xfs_sb_t, sb_dirblklog),  0 },
118     { offsetof(xfs_sb_t, sb_logsectlog), 0 },
119     { offsetof(xfs_sb_t, sb_logsectsize),0 },
120     { offsetof(xfs_sb_t, sb_logsunit),   0 },
121     { offsetof(xfs_sb_t, sb_features2),  0 },
122     { offsetof(xfs_sb_t, sb_bad_features2), 0 },
123     { sizeof(xfs_sb_t),                  0 }
124 };
125
126 /*
127  * Return a pointer to an initialized xfs_mount structure.
128  */
129 xfs_mount_t *
130 xfs_mount_init(void)
131 {
132         xfs_mount_t *mp;
133
134         mp = kmem_zalloc(sizeof(xfs_mount_t), KM_SLEEP);
135
136         if (xfs_icsb_init_counters(mp)) {
137                 mp->m_flags |= XFS_MOUNT_NO_PERCPU_SB;
138         }
139
140         spin_lock_init(&mp->m_sb_lock);
141         mutex_init(&mp->m_ilock);
142         mutex_init(&mp->m_growlock);
143         atomic_set(&mp->m_active_trans, 0);
144
145         return mp;
146 }
147
148 /*
149  * Free up the resources associated with a mount structure.  Assume that
150  * the structure was initially zeroed, so we can tell which fields got
151  * initialized.
152  */
153 void
154 xfs_mount_free(
155         xfs_mount_t     *mp)
156 {
157         if (mp->m_perag) {
158                 int     agno;
159
160                 for (agno = 0; agno < mp->m_maxagi; agno++)
161                         if (mp->m_perag[agno].pagb_list)
162                                 kmem_free(mp->m_perag[agno].pagb_list,
163                                                 sizeof(xfs_perag_busy_t) *
164                                                         XFS_PAGB_NUM_SLOTS);
165                 kmem_free(mp->m_perag,
166                           sizeof(xfs_perag_t) * mp->m_sb.sb_agcount);
167         }
168
169         spinlock_destroy(&mp->m_ail_lock);
170         spinlock_destroy(&mp->m_sb_lock);
171         mutex_destroy(&mp->m_ilock);
172         mutex_destroy(&mp->m_growlock);
173         if (mp->m_quotainfo)
174                 XFS_QM_DONE(mp);
175
176         if (mp->m_fsname != NULL)
177                 kmem_free(mp->m_fsname, mp->m_fsname_len);
178         if (mp->m_rtname != NULL)
179                 kmem_free(mp->m_rtname, strlen(mp->m_rtname) + 1);
180         if (mp->m_logname != NULL)
181                 kmem_free(mp->m_logname, strlen(mp->m_logname) + 1);
182
183         xfs_icsb_destroy_counters(mp);
184 }
185
186 /*
187  * Check size of device based on the (data/realtime) block count.
188  * Note: this check is used by the growfs code as well as mount.
189  */
190 int
191 xfs_sb_validate_fsb_count(
192         xfs_sb_t        *sbp,
193         __uint64_t      nblocks)
194 {
195         ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
196         ASSERT(sbp->sb_blocklog >= BBSHIFT);
197
198 #if XFS_BIG_BLKNOS     /* Limited by ULONG_MAX of page cache index */
199         if (nblocks >> (PAGE_CACHE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
200                 return E2BIG;
201 #else                  /* Limited by UINT_MAX of sectors */
202         if (nblocks << (sbp->sb_blocklog - BBSHIFT) > UINT_MAX)
203                 return E2BIG;
204 #endif
205         return 0;
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         if (xfs_sb_validate_fsb_count(sbp, sbp->sb_dblocks) ||
290             xfs_sb_validate_fsb_count(sbp, sbp->sb_rblocks)) {
291                 xfs_fs_mount_cmn_err(flags,
292                         "file system too large to be mounted on this system.");
293                 return XFS_ERROR(E2BIG);
294         }
295
296         if (unlikely(sbp->sb_inprogress)) {
297                 xfs_fs_mount_cmn_err(flags, "file system busy");
298                 return XFS_ERROR(EFSCORRUPTED);
299         }
300
301         /*
302          * Version 1 directory format has never worked on Linux.
303          */
304         if (unlikely(!xfs_sb_version_hasdirv2(sbp))) {
305                 xfs_fs_mount_cmn_err(flags,
306                         "file system using version 1 directory format");
307                 return XFS_ERROR(ENOSYS);
308         }
309
310         /*
311          * Until this is fixed only page-sized or smaller data blocks work.
312          */
313         if (unlikely(sbp->sb_blocksize > PAGE_SIZE)) {
314                 xfs_fs_mount_cmn_err(flags,
315                         "file system with blocksize %d bytes",
316                         sbp->sb_blocksize);
317                 xfs_fs_mount_cmn_err(flags,
318                         "only pagesize (%ld) or less will currently work.",
319                         PAGE_SIZE);
320                 return XFS_ERROR(ENOSYS);
321         }
322
323         return 0;
324 }
325
326 STATIC void
327 xfs_initialize_perag_icache(
328         xfs_perag_t     *pag)
329 {
330         if (!pag->pag_ici_init) {
331                 rwlock_init(&pag->pag_ici_lock);
332                 INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
333                 pag->pag_ici_init = 1;
334         }
335 }
336
337 xfs_agnumber_t
338 xfs_initialize_perag(
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 ((mp->m_flags & XFS_MOUNT_SMALL_INUMS) && 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                         xfs_initialize_perag_icache(pag);
391                 }
392         } else {
393                 /* Setup default behavior for smaller filesystems */
394                 for (index = 0; index < agcount; index++) {
395                         pag = &mp->m_perag[index];
396                         pag->pagi_inodeok = 1;
397                         xfs_initialize_perag_icache(pag);
398                 }
399         }
400         return index;
401 }
402
403 void
404 xfs_sb_from_disk(
405         xfs_sb_t        *to,
406         xfs_dsb_t       *from)
407 {
408         to->sb_magicnum = be32_to_cpu(from->sb_magicnum);
409         to->sb_blocksize = be32_to_cpu(from->sb_blocksize);
410         to->sb_dblocks = be64_to_cpu(from->sb_dblocks);
411         to->sb_rblocks = be64_to_cpu(from->sb_rblocks);
412         to->sb_rextents = be64_to_cpu(from->sb_rextents);
413         memcpy(&to->sb_uuid, &from->sb_uuid, sizeof(to->sb_uuid));
414         to->sb_logstart = be64_to_cpu(from->sb_logstart);
415         to->sb_rootino = be64_to_cpu(from->sb_rootino);
416         to->sb_rbmino = be64_to_cpu(from->sb_rbmino);
417         to->sb_rsumino = be64_to_cpu(from->sb_rsumino);
418         to->sb_rextsize = be32_to_cpu(from->sb_rextsize);
419         to->sb_agblocks = be32_to_cpu(from->sb_agblocks);
420         to->sb_agcount = be32_to_cpu(from->sb_agcount);
421         to->sb_rbmblocks = be32_to_cpu(from->sb_rbmblocks);
422         to->sb_logblocks = be32_to_cpu(from->sb_logblocks);
423         to->sb_versionnum = be16_to_cpu(from->sb_versionnum);
424         to->sb_sectsize = be16_to_cpu(from->sb_sectsize);
425         to->sb_inodesize = be16_to_cpu(from->sb_inodesize);
426         to->sb_inopblock = be16_to_cpu(from->sb_inopblock);
427         memcpy(&to->sb_fname, &from->sb_fname, sizeof(to->sb_fname));
428         to->sb_blocklog = from->sb_blocklog;
429         to->sb_sectlog = from->sb_sectlog;
430         to->sb_inodelog = from->sb_inodelog;
431         to->sb_inopblog = from->sb_inopblog;
432         to->sb_agblklog = from->sb_agblklog;
433         to->sb_rextslog = from->sb_rextslog;
434         to->sb_inprogress = from->sb_inprogress;
435         to->sb_imax_pct = from->sb_imax_pct;
436         to->sb_icount = be64_to_cpu(from->sb_icount);
437         to->sb_ifree = be64_to_cpu(from->sb_ifree);
438         to->sb_fdblocks = be64_to_cpu(from->sb_fdblocks);
439         to->sb_frextents = be64_to_cpu(from->sb_frextents);
440         to->sb_uquotino = be64_to_cpu(from->sb_uquotino);
441         to->sb_gquotino = be64_to_cpu(from->sb_gquotino);
442         to->sb_qflags = be16_to_cpu(from->sb_qflags);
443         to->sb_flags = from->sb_flags;
444         to->sb_shared_vn = from->sb_shared_vn;
445         to->sb_inoalignmt = be32_to_cpu(from->sb_inoalignmt);
446         to->sb_unit = be32_to_cpu(from->sb_unit);
447         to->sb_width = be32_to_cpu(from->sb_width);
448         to->sb_dirblklog = from->sb_dirblklog;
449         to->sb_logsectlog = from->sb_logsectlog;
450         to->sb_logsectsize = be16_to_cpu(from->sb_logsectsize);
451         to->sb_logsunit = be32_to_cpu(from->sb_logsunit);
452         to->sb_features2 = be32_to_cpu(from->sb_features2);
453         to->sb_bad_features2 = be32_to_cpu(from->sb_bad_features2);
454 }
455
456 /*
457  * Copy in core superblock to ondisk one.
458  *
459  * The fields argument is mask of superblock fields to copy.
460  */
461 void
462 xfs_sb_to_disk(
463         xfs_dsb_t       *to,
464         xfs_sb_t        *from,
465         __int64_t       fields)
466 {
467         xfs_caddr_t     to_ptr = (xfs_caddr_t)to;
468         xfs_caddr_t     from_ptr = (xfs_caddr_t)from;
469         xfs_sb_field_t  f;
470         int             first;
471         int             size;
472
473         ASSERT(fields);
474         if (!fields)
475                 return;
476
477         while (fields) {
478                 f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
479                 first = xfs_sb_info[f].offset;
480                 size = xfs_sb_info[f + 1].offset - first;
481
482                 ASSERT(xfs_sb_info[f].type == 0 || xfs_sb_info[f].type == 1);
483
484                 if (size == 1 || xfs_sb_info[f].type == 1) {
485                         memcpy(to_ptr + first, from_ptr + first, size);
486                 } else {
487                         switch (size) {
488                         case 2:
489                                 *(__be16 *)(to_ptr + first) =
490                                         cpu_to_be16(*(__u16 *)(from_ptr + first));
491                                 break;
492                         case 4:
493                                 *(__be32 *)(to_ptr + first) =
494                                         cpu_to_be32(*(__u32 *)(from_ptr + first));
495                                 break;
496                         case 8:
497                                 *(__be64 *)(to_ptr + first) =
498                                         cpu_to_be64(*(__u64 *)(from_ptr + first));
499                                 break;
500                         default:
501                                 ASSERT(0);
502                         }
503                 }
504
505                 fields &= ~(1LL << f);
506         }
507 }
508
509 /*
510  * xfs_readsb
511  *
512  * Does the initial read of the superblock.
513  */
514 int
515 xfs_readsb(xfs_mount_t *mp, int flags)
516 {
517         unsigned int    sector_size;
518         unsigned int    extra_flags;
519         xfs_buf_t       *bp;
520         int             error;
521
522         ASSERT(mp->m_sb_bp == NULL);
523         ASSERT(mp->m_ddev_targp != NULL);
524
525         /*
526          * Allocate a (locked) buffer to hold the superblock.
527          * This will be kept around at all times to optimize
528          * access to the superblock.
529          */
530         sector_size = xfs_getsize_buftarg(mp->m_ddev_targp);
531         extra_flags = XFS_BUF_LOCK | XFS_BUF_MANAGE | XFS_BUF_MAPPED;
532
533         bp = xfs_buf_read_flags(mp->m_ddev_targp, XFS_SB_DADDR,
534                                 BTOBB(sector_size), extra_flags);
535         if (!bp || XFS_BUF_ISERROR(bp)) {
536                 xfs_fs_mount_cmn_err(flags, "SB read failed");
537                 error = bp ? XFS_BUF_GETERROR(bp) : ENOMEM;
538                 goto fail;
539         }
540         ASSERT(XFS_BUF_ISBUSY(bp));
541         ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
542
543         /*
544          * Initialize the mount structure from the superblock.
545          * But first do some basic consistency checking.
546          */
547         xfs_sb_from_disk(&mp->m_sb, XFS_BUF_TO_SBP(bp));
548
549         error = xfs_mount_validate_sb(mp, &(mp->m_sb), flags);
550         if (error) {
551                 xfs_fs_mount_cmn_err(flags, "SB validate failed");
552                 goto fail;
553         }
554
555         /*
556          * We must be able to do sector-sized and sector-aligned IO.
557          */
558         if (sector_size > mp->m_sb.sb_sectsize) {
559                 xfs_fs_mount_cmn_err(flags,
560                         "device supports only %u byte sectors (not %u)",
561                         sector_size, mp->m_sb.sb_sectsize);
562                 error = ENOSYS;
563                 goto fail;
564         }
565
566         /*
567          * If device sector size is smaller than the superblock size,
568          * re-read the superblock so the buffer is correctly sized.
569          */
570         if (sector_size < mp->m_sb.sb_sectsize) {
571                 XFS_BUF_UNMANAGE(bp);
572                 xfs_buf_relse(bp);
573                 sector_size = mp->m_sb.sb_sectsize;
574                 bp = xfs_buf_read_flags(mp->m_ddev_targp, XFS_SB_DADDR,
575                                         BTOBB(sector_size), extra_flags);
576                 if (!bp || XFS_BUF_ISERROR(bp)) {
577                         xfs_fs_mount_cmn_err(flags, "SB re-read failed");
578                         error = bp ? XFS_BUF_GETERROR(bp) : ENOMEM;
579                         goto fail;
580                 }
581                 ASSERT(XFS_BUF_ISBUSY(bp));
582                 ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
583         }
584
585         /* Initialize per-cpu counters */
586         xfs_icsb_reinit_counters(mp);
587
588         mp->m_sb_bp = bp;
589         xfs_buf_relse(bp);
590         ASSERT(XFS_BUF_VALUSEMA(bp) > 0);
591         return 0;
592
593  fail:
594         if (bp) {
595                 XFS_BUF_UNMANAGE(bp);
596                 xfs_buf_relse(bp);
597         }
598         return error;
599 }
600
601
602 /*
603  * xfs_mount_common
604  *
605  * Mount initialization code establishing various mount
606  * fields from the superblock associated with the given
607  * mount structure
608  */
609 STATIC void
610 xfs_mount_common(xfs_mount_t *mp, xfs_sb_t *sbp)
611 {
612         int     i;
613
614         mp->m_agfrotor = mp->m_agirotor = 0;
615         spin_lock_init(&mp->m_agirotor_lock);
616         mp->m_maxagi = mp->m_sb.sb_agcount;
617         mp->m_blkbit_log = sbp->sb_blocklog + XFS_NBBYLOG;
618         mp->m_blkbb_log = sbp->sb_blocklog - BBSHIFT;
619         mp->m_sectbb_log = sbp->sb_sectlog - BBSHIFT;
620         mp->m_agno_log = xfs_highbit32(sbp->sb_agcount - 1) + 1;
621         mp->m_agino_log = sbp->sb_inopblog + sbp->sb_agblklog;
622         mp->m_litino = sbp->sb_inodesize -
623                 ((uint)sizeof(xfs_dinode_core_t) + (uint)sizeof(xfs_agino_t));
624         mp->m_blockmask = sbp->sb_blocksize - 1;
625         mp->m_blockwsize = sbp->sb_blocksize >> XFS_WORDLOG;
626         mp->m_blockwmask = mp->m_blockwsize - 1;
627         INIT_LIST_HEAD(&mp->m_del_inodes);
628
629         /*
630          * Setup for attributes, in case they get created.
631          * This value is for inodes getting attributes for the first time,
632          * the per-inode value is for old attribute values.
633          */
634         ASSERT(sbp->sb_inodesize >= 256 && sbp->sb_inodesize <= 2048);
635         switch (sbp->sb_inodesize) {
636         case 256:
637                 mp->m_attroffset = XFS_LITINO(mp) -
638                                    XFS_BMDR_SPACE_CALC(MINABTPTRS);
639                 break;
640         case 512:
641         case 1024:
642         case 2048:
643                 mp->m_attroffset = XFS_BMDR_SPACE_CALC(6 * MINABTPTRS);
644                 break;
645         default:
646                 ASSERT(0);
647         }
648         ASSERT(mp->m_attroffset < XFS_LITINO(mp));
649
650         for (i = 0; i < 2; i++) {
651                 mp->m_alloc_mxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
652                         xfs_alloc, i == 0);
653                 mp->m_alloc_mnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
654                         xfs_alloc, i == 0);
655         }
656         for (i = 0; i < 2; i++) {
657                 mp->m_bmap_dmxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
658                         xfs_bmbt, i == 0);
659                 mp->m_bmap_dmnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
660                         xfs_bmbt, i == 0);
661         }
662         for (i = 0; i < 2; i++) {
663                 mp->m_inobt_mxr[i] = XFS_BTREE_BLOCK_MAXRECS(sbp->sb_blocksize,
664                         xfs_inobt, i == 0);
665                 mp->m_inobt_mnr[i] = XFS_BTREE_BLOCK_MINRECS(sbp->sb_blocksize,
666                         xfs_inobt, i == 0);
667         }
668
669         mp->m_bsize = XFS_FSB_TO_BB(mp, 1);
670         mp->m_ialloc_inos = (int)MAX((__uint16_t)XFS_INODES_PER_CHUNK,
671                                         sbp->sb_inopblock);
672         mp->m_ialloc_blks = mp->m_ialloc_inos >> sbp->sb_inopblog;
673 }
674
675 /*
676  * xfs_initialize_perag_data
677  *
678  * Read in each per-ag structure so we can count up the number of
679  * allocated inodes, free inodes and used filesystem blocks as this
680  * information is no longer persistent in the superblock. Once we have
681  * this information, write it into the in-core superblock structure.
682  */
683 STATIC int
684 xfs_initialize_perag_data(xfs_mount_t *mp, xfs_agnumber_t agcount)
685 {
686         xfs_agnumber_t  index;
687         xfs_perag_t     *pag;
688         xfs_sb_t        *sbp = &mp->m_sb;
689         uint64_t        ifree = 0;
690         uint64_t        ialloc = 0;
691         uint64_t        bfree = 0;
692         uint64_t        bfreelst = 0;
693         uint64_t        btree = 0;
694         int             error;
695
696         for (index = 0; index < agcount; index++) {
697                 /*
698                  * read the agf, then the agi. This gets us
699                  * all the inforamtion we need and populates the
700                  * per-ag structures for us.
701                  */
702                 error = xfs_alloc_pagf_init(mp, NULL, index, 0);
703                 if (error)
704                         return error;
705
706                 error = xfs_ialloc_pagi_init(mp, NULL, index);
707                 if (error)
708                         return error;
709                 pag = &mp->m_perag[index];
710                 ifree += pag->pagi_freecount;
711                 ialloc += pag->pagi_count;
712                 bfree += pag->pagf_freeblks;
713                 bfreelst += pag->pagf_flcount;
714                 btree += pag->pagf_btreeblks;
715         }
716         /*
717          * Overwrite incore superblock counters with just-read data
718          */
719         spin_lock(&mp->m_sb_lock);
720         sbp->sb_ifree = ifree;
721         sbp->sb_icount = ialloc;
722         sbp->sb_fdblocks = bfree + bfreelst + btree;
723         spin_unlock(&mp->m_sb_lock);
724
725         /* Fixup the per-cpu counters as well. */
726         xfs_icsb_reinit_counters(mp);
727
728         return 0;
729 }
730
731 /*
732  * Update alignment values based on mount options and sb values
733  */
734 STATIC int
735 xfs_update_alignment(xfs_mount_t *mp, int mfsi_flags, __uint64_t *update_flags)
736 {
737         xfs_sb_t        *sbp = &(mp->m_sb);
738
739         if (mp->m_dalign && !(mfsi_flags & XFS_MFSI_SECOND)) {
740                 /*
741                  * If stripe unit and stripe width are not multiples
742                  * of the fs blocksize turn off alignment.
743                  */
744                 if ((BBTOB(mp->m_dalign) & mp->m_blockmask) ||
745                     (BBTOB(mp->m_swidth) & mp->m_blockmask)) {
746                         if (mp->m_flags & XFS_MOUNT_RETERR) {
747                                 cmn_err(CE_WARN,
748                                         "XFS: alignment check 1 failed");
749                                 return XFS_ERROR(EINVAL);
750                         }
751                         mp->m_dalign = mp->m_swidth = 0;
752                 } else {
753                         /*
754                          * Convert the stripe unit and width to FSBs.
755                          */
756                         mp->m_dalign = XFS_BB_TO_FSBT(mp, mp->m_dalign);
757                         if (mp->m_dalign && (sbp->sb_agblocks % mp->m_dalign)) {
758                                 if (mp->m_flags & XFS_MOUNT_RETERR) {
759                                         return XFS_ERROR(EINVAL);
760                                 }
761                                 xfs_fs_cmn_err(CE_WARN, mp,
762 "stripe alignment turned off: sunit(%d)/swidth(%d) incompatible with agsize(%d)",
763                                         mp->m_dalign, mp->m_swidth,
764                                         sbp->sb_agblocks);
765
766                                 mp->m_dalign = 0;
767                                 mp->m_swidth = 0;
768                         } else if (mp->m_dalign) {
769                                 mp->m_swidth = XFS_BB_TO_FSBT(mp, mp->m_swidth);
770                         } else {
771                                 if (mp->m_flags & XFS_MOUNT_RETERR) {
772                                         xfs_fs_cmn_err(CE_WARN, mp,
773 "stripe alignment turned off: sunit(%d) less than bsize(%d)",
774                                                 mp->m_dalign,
775                                                 mp->m_blockmask +1);
776                                         return XFS_ERROR(EINVAL);
777                                 }
778                                 mp->m_swidth = 0;
779                         }
780                 }
781
782                 /*
783                  * Update superblock with new values
784                  * and log changes
785                  */
786                 if (xfs_sb_version_hasdalign(sbp)) {
787                         if (sbp->sb_unit != mp->m_dalign) {
788                                 sbp->sb_unit = mp->m_dalign;
789                                 *update_flags |= XFS_SB_UNIT;
790                         }
791                         if (sbp->sb_width != mp->m_swidth) {
792                                 sbp->sb_width = mp->m_swidth;
793                                 *update_flags |= XFS_SB_WIDTH;
794                         }
795                 }
796         } else if ((mp->m_flags & XFS_MOUNT_NOALIGN) != XFS_MOUNT_NOALIGN &&
797                     xfs_sb_version_hasdalign(&mp->m_sb)) {
798                         mp->m_dalign = sbp->sb_unit;
799                         mp->m_swidth = sbp->sb_width;
800         }
801
802         return 0;
803 }
804
805 /*
806  * Set the maximum inode count for this filesystem
807  */
808 STATIC void
809 xfs_set_maxicount(xfs_mount_t *mp)
810 {
811         xfs_sb_t        *sbp = &(mp->m_sb);
812         __uint64_t      icount;
813
814         if (sbp->sb_imax_pct) {
815                 /*
816                  * Make sure the maximum inode count is a multiple
817                  * of the units we allocate inodes in.
818                  */
819                 icount = sbp->sb_dblocks * sbp->sb_imax_pct;
820                 do_div(icount, 100);
821                 do_div(icount, mp->m_ialloc_blks);
822                 mp->m_maxicount = (icount * mp->m_ialloc_blks)  <<
823                                    sbp->sb_inopblog;
824         } else {
825                 mp->m_maxicount = 0;
826         }
827 }
828
829 /*
830  * Set the default minimum read and write sizes unless
831  * already specified in a mount option.
832  * We use smaller I/O sizes when the file system
833  * is being used for NFS service (wsync mount option).
834  */
835 STATIC void
836 xfs_set_rw_sizes(xfs_mount_t *mp)
837 {
838         xfs_sb_t        *sbp = &(mp->m_sb);
839         int             readio_log, writeio_log;
840
841         if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
842                 if (mp->m_flags & XFS_MOUNT_WSYNC) {
843                         readio_log = XFS_WSYNC_READIO_LOG;
844                         writeio_log = XFS_WSYNC_WRITEIO_LOG;
845                 } else {
846                         readio_log = XFS_READIO_LOG_LARGE;
847                         writeio_log = XFS_WRITEIO_LOG_LARGE;
848                 }
849         } else {
850                 readio_log = mp->m_readio_log;
851                 writeio_log = mp->m_writeio_log;
852         }
853
854         if (sbp->sb_blocklog > readio_log) {
855                 mp->m_readio_log = sbp->sb_blocklog;
856         } else {
857                 mp->m_readio_log = readio_log;
858         }
859         mp->m_readio_blocks = 1 << (mp->m_readio_log - sbp->sb_blocklog);
860         if (sbp->sb_blocklog > writeio_log) {
861                 mp->m_writeio_log = sbp->sb_blocklog;
862         } else {
863                 mp->m_writeio_log = writeio_log;
864         }
865         mp->m_writeio_blocks = 1 << (mp->m_writeio_log - sbp->sb_blocklog);
866 }
867
868 /*
869  * Set whether we're using inode alignment.
870  */
871 STATIC void
872 xfs_set_inoalignment(xfs_mount_t *mp)
873 {
874         if (xfs_sb_version_hasalign(&mp->m_sb) &&
875             mp->m_sb.sb_inoalignmt >=
876             XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size))
877                 mp->m_inoalign_mask = mp->m_sb.sb_inoalignmt - 1;
878         else
879                 mp->m_inoalign_mask = 0;
880         /*
881          * If we are using stripe alignment, check whether
882          * the stripe unit is a multiple of the inode alignment
883          */
884         if (mp->m_dalign && mp->m_inoalign_mask &&
885             !(mp->m_dalign & mp->m_inoalign_mask))
886                 mp->m_sinoalign = mp->m_dalign;
887         else
888                 mp->m_sinoalign = 0;
889 }
890
891 /*
892  * Check that the data (and log if separate) are an ok size.
893  */
894 STATIC int
895 xfs_check_sizes(xfs_mount_t *mp, int mfsi_flags)
896 {
897         xfs_buf_t       *bp;
898         xfs_daddr_t     d;
899         int             error;
900
901         d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
902         if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
903                 cmn_err(CE_WARN, "XFS: size check 1 failed");
904                 return XFS_ERROR(E2BIG);
905         }
906         error = xfs_read_buf(mp, mp->m_ddev_targp,
907                              d - XFS_FSS_TO_BB(mp, 1),
908                              XFS_FSS_TO_BB(mp, 1), 0, &bp);
909         if (!error) {
910                 xfs_buf_relse(bp);
911         } else {
912                 cmn_err(CE_WARN, "XFS: size check 2 failed");
913                 if (error == ENOSPC)
914                         error = XFS_ERROR(E2BIG);
915                 return error;
916         }
917
918         if (((mfsi_flags & XFS_MFSI_CLIENT) == 0) &&
919             mp->m_logdev_targp != mp->m_ddev_targp) {
920                 d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
921                 if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
922                         cmn_err(CE_WARN, "XFS: size check 3 failed");
923                         return XFS_ERROR(E2BIG);
924                 }
925                 error = xfs_read_buf(mp, mp->m_logdev_targp,
926                                      d - XFS_FSB_TO_BB(mp, 1),
927                                      XFS_FSB_TO_BB(mp, 1), 0, &bp);
928                 if (!error) {
929                         xfs_buf_relse(bp);
930                 } else {
931                         cmn_err(CE_WARN, "XFS: size check 3 failed");
932                         if (error == ENOSPC)
933                                 error = XFS_ERROR(E2BIG);
934                         return error;
935                 }
936         }
937         return 0;
938 }
939
940 /*
941  * xfs_mountfs
942  *
943  * This function does the following on an initial mount of a file system:
944  *      - reads the superblock from disk and init the mount struct
945  *      - if we're a 32-bit kernel, do a size check on the superblock
946  *              so we don't mount terabyte filesystems
947  *      - init mount struct realtime fields
948  *      - allocate inode hash table for fs
949  *      - init directory manager
950  *      - perform recovery and init the log manager
951  */
952 int
953 xfs_mountfs(
954         xfs_mount_t     *mp,
955         int             mfsi_flags)
956 {
957         xfs_sb_t        *sbp = &(mp->m_sb);
958         xfs_inode_t     *rip;
959         bhv_vnode_t     *rvp = NULL;
960         __uint64_t      resblks;
961         __int64_t       update_flags = 0LL;
962         uint            quotamount, quotaflags;
963         int             agno;
964         int             uuid_mounted = 0;
965         int             error = 0;
966
967         if (mp->m_sb_bp == NULL) {
968                 error = xfs_readsb(mp, mfsi_flags);
969                 if (error)
970                         return error;
971         }
972         xfs_mount_common(mp, sbp);
973
974         /*
975          * Check for a mismatched features2 values.  Older kernels
976          * read & wrote into the wrong sb offset for sb_features2
977          * on some platforms due to xfs_sb_t not being 64bit size aligned
978          * when sb_features2 was added, which made older superblock
979          * reading/writing routines swap it as a 64-bit value.
980          *
981          * For backwards compatibility, we make both slots equal.
982          *
983          * If we detect a mismatched field, we OR the set bits into the
984          * existing features2 field in case it has already been modified; we
985          * don't want to lose any features.  We then update the bad location
986          * with the ORed value so that older kernels will see any features2
987          * flags, and mark the two fields as needing updates once the
988          * transaction subsystem is online.
989          */
990         if (xfs_sb_has_mismatched_features2(sbp)) {
991                 cmn_err(CE_WARN,
992                         "XFS: correcting sb_features alignment problem");
993                 sbp->sb_features2 |= sbp->sb_bad_features2;
994                 sbp->sb_bad_features2 = sbp->sb_features2;
995                 update_flags |= XFS_SB_FEATURES2 | XFS_SB_BAD_FEATURES2;
996
997                 /*
998                  * Re-check for ATTR2 in case it was found in bad_features2
999                  * slot.
1000                  */
1001                 if (xfs_sb_version_hasattr2(&mp->m_sb))
1002                         mp->m_flags |= XFS_MOUNT_ATTR2;
1003
1004         }
1005
1006         /*
1007          * Check if sb_agblocks is aligned at stripe boundary
1008          * If sb_agblocks is NOT aligned turn off m_dalign since
1009          * allocator alignment is within an ag, therefore ag has
1010          * to be aligned at stripe boundary.
1011          */
1012         error = xfs_update_alignment(mp, mfsi_flags, &update_flags);
1013         if (error)
1014                 goto error1;
1015
1016         xfs_alloc_compute_maxlevels(mp);
1017         xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK);
1018         xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK);
1019         xfs_ialloc_compute_maxlevels(mp);
1020
1021         xfs_set_maxicount(mp);
1022
1023         mp->m_maxioffset = xfs_max_file_offset(sbp->sb_blocklog);
1024
1025         /*
1026          * XFS uses the uuid from the superblock as the unique
1027          * identifier for fsid.  We can not use the uuid from the volume
1028          * since a single partition filesystem is identical to a single
1029          * partition volume/filesystem.
1030          */
1031         if ((mfsi_flags & XFS_MFSI_SECOND) == 0 &&
1032             (mp->m_flags & XFS_MOUNT_NOUUID) == 0) {
1033                 if (xfs_uuid_mount(mp)) {
1034                         error = XFS_ERROR(EINVAL);
1035                         goto error1;
1036                 }
1037                 uuid_mounted=1;
1038         }
1039
1040         /*
1041          * Set the minimum read and write sizes
1042          */
1043         xfs_set_rw_sizes(mp);
1044
1045         /*
1046          * Set the inode cluster size.
1047          * This may still be overridden by the file system
1048          * block size if it is larger than the chosen cluster size.
1049          */
1050         mp->m_inode_cluster_size = XFS_INODE_BIG_CLUSTER_SIZE;
1051
1052         /*
1053          * Set inode alignment fields
1054          */
1055         xfs_set_inoalignment(mp);
1056
1057         /*
1058          * Check that the data (and log if separate) are an ok size.
1059          */
1060         error = xfs_check_sizes(mp, mfsi_flags);
1061         if (error)
1062                 goto error1;
1063
1064         /*
1065          * Initialize realtime fields in the mount structure
1066          */
1067         error = xfs_rtmount_init(mp);
1068         if (error) {
1069                 cmn_err(CE_WARN, "XFS: RT mount failed");
1070                 goto error1;
1071         }
1072
1073         /*
1074          * For client case we are done now
1075          */
1076         if (mfsi_flags & XFS_MFSI_CLIENT) {
1077                 return 0;
1078         }
1079
1080         /*
1081          *  Copies the low order bits of the timestamp and the randomly
1082          *  set "sequence" number out of a UUID.
1083          */
1084         uuid_getnodeuniq(&sbp->sb_uuid, mp->m_fixedfsid);
1085
1086         mp->m_dmevmask = 0;     /* not persistent; set after each mount */
1087
1088         xfs_dir_mount(mp);
1089
1090         /*
1091          * Initialize the attribute manager's entries.
1092          */
1093         mp->m_attr_magicpct = (mp->m_sb.sb_blocksize * 37) / 100;
1094
1095         /*
1096          * Initialize the precomputed transaction reservations values.
1097          */
1098         xfs_trans_init(mp);
1099
1100         /*
1101          * Allocate and initialize the per-ag data.
1102          */
1103         init_rwsem(&mp->m_peraglock);
1104         mp->m_perag =
1105                 kmem_zalloc(sbp->sb_agcount * sizeof(xfs_perag_t), KM_SLEEP);
1106
1107         mp->m_maxagi = xfs_initialize_perag(mp, sbp->sb_agcount);
1108
1109         /*
1110          * log's mount-time initialization. Perform 1st part recovery if needed
1111          */
1112         if (likely(sbp->sb_logblocks > 0)) {    /* check for volume case */
1113                 error = xfs_log_mount(mp, mp->m_logdev_targp,
1114                                       XFS_FSB_TO_DADDR(mp, sbp->sb_logstart),
1115                                       XFS_FSB_TO_BB(mp, sbp->sb_logblocks));
1116                 if (error) {
1117                         cmn_err(CE_WARN, "XFS: log mount failed");
1118                         goto error2;
1119                 }
1120         } else {        /* No log has been defined */
1121                 cmn_err(CE_WARN, "XFS: no log defined");
1122                 XFS_ERROR_REPORT("xfs_mountfs_int(1)", XFS_ERRLEVEL_LOW, mp);
1123                 error = XFS_ERROR(EFSCORRUPTED);
1124                 goto error2;
1125         }
1126
1127         /*
1128          * Now the log is mounted, we know if it was an unclean shutdown or
1129          * not. If it was, with the first phase of recovery has completed, we
1130          * have consistent AG blocks on disk. We have not recovered EFIs yet,
1131          * but they are recovered transactionally in the second recovery phase
1132          * later.
1133          *
1134          * Hence we can safely re-initialise incore superblock counters from
1135          * the per-ag data. These may not be correct if the filesystem was not
1136          * cleanly unmounted, so we need to wait for recovery to finish before
1137          * doing this.
1138          *
1139          * If the filesystem was cleanly unmounted, then we can trust the
1140          * values in the superblock to be correct and we don't need to do
1141          * anything here.
1142          *
1143          * If we are currently making the filesystem, the initialisation will
1144          * fail as the perag data is in an undefined state.
1145          */
1146
1147         if (xfs_sb_version_haslazysbcount(&mp->m_sb) &&
1148             !XFS_LAST_UNMOUNT_WAS_CLEAN(mp) &&
1149              !mp->m_sb.sb_inprogress) {
1150                 error = xfs_initialize_perag_data(mp, sbp->sb_agcount);
1151                 if (error) {
1152                         goto error2;
1153                 }
1154         }
1155         /*
1156          * Get and sanity-check the root inode.
1157          * Save the pointer to it in the mount structure.
1158          */
1159         error = xfs_iget(mp, NULL, sbp->sb_rootino, 0, XFS_ILOCK_EXCL, &rip, 0);
1160         if (error) {
1161                 cmn_err(CE_WARN, "XFS: failed to read root inode");
1162                 goto error3;
1163         }
1164
1165         ASSERT(rip != NULL);
1166         rvp = XFS_ITOV(rip);
1167
1168         if (unlikely((rip->i_d.di_mode & S_IFMT) != S_IFDIR)) {
1169                 cmn_err(CE_WARN, "XFS: corrupted root inode");
1170                 cmn_err(CE_WARN, "Device %s - root %llu is not a directory",
1171                         XFS_BUFTARG_NAME(mp->m_ddev_targp),
1172                         (unsigned long long)rip->i_ino);
1173                 xfs_iunlock(rip, XFS_ILOCK_EXCL);
1174                 XFS_ERROR_REPORT("xfs_mountfs_int(2)", XFS_ERRLEVEL_LOW,
1175                                  mp);
1176                 error = XFS_ERROR(EFSCORRUPTED);
1177                 goto error4;
1178         }
1179         mp->m_rootip = rip;     /* save it */
1180
1181         xfs_iunlock(rip, XFS_ILOCK_EXCL);
1182
1183         /*
1184          * Initialize realtime inode pointers in the mount structure
1185          */
1186         error = xfs_rtmount_inodes(mp);
1187         if (error) {
1188                 /*
1189                  * Free up the root inode.
1190                  */
1191                 cmn_err(CE_WARN, "XFS: failed to read RT inodes");
1192                 goto error4;
1193         }
1194
1195         /*
1196          * If fs is not mounted readonly, then update the superblock changes.
1197          */
1198         if (update_flags && !(mp->m_flags & XFS_MOUNT_RDONLY))
1199                 xfs_mount_log_sb(mp, update_flags);
1200
1201         /*
1202          * Initialise the XFS quota management subsystem for this mount
1203          */
1204         error = XFS_QM_INIT(mp, &quotamount, &quotaflags);
1205         if (error)
1206                 goto error4;
1207
1208         /*
1209          * Finish recovering the file system.  This part needed to be
1210          * delayed until after the root and real-time bitmap inodes
1211          * were consistently read in.
1212          */
1213         error = xfs_log_mount_finish(mp, mfsi_flags);
1214         if (error) {
1215                 cmn_err(CE_WARN, "XFS: log mount finish failed");
1216                 goto error4;
1217         }
1218
1219         /*
1220          * Complete the quota initialisation, post-log-replay component.
1221          */
1222         error = XFS_QM_MOUNT(mp, quotamount, quotaflags, mfsi_flags);
1223         if (error)
1224                 goto error4;
1225
1226         /*
1227          * Now we are mounted, reserve a small amount of unused space for
1228          * privileged transactions. This is needed so that transaction
1229          * space required for critical operations can dip into this pool
1230          * when at ENOSPC. This is needed for operations like create with
1231          * attr, unwritten extent conversion at ENOSPC, etc. Data allocations
1232          * are not allowed to use this reserved space.
1233          *
1234          * We default to 5% or 1024 fsbs of space reserved, whichever is smaller.
1235          * This may drive us straight to ENOSPC on mount, but that implies
1236          * we were already there on the last unmount.
1237          */
1238         resblks = mp->m_sb.sb_dblocks;
1239         do_div(resblks, 20);
1240         resblks = min_t(__uint64_t, resblks, 1024);
1241         xfs_reserve_blocks(mp, &resblks, NULL);
1242
1243         return 0;
1244
1245  error4:
1246         /*
1247          * Free up the root inode.
1248          */
1249         VN_RELE(rvp);
1250  error3:
1251         xfs_log_unmount_dealloc(mp);
1252  error2:
1253         for (agno = 0; agno < sbp->sb_agcount; agno++)
1254                 if (mp->m_perag[agno].pagb_list)
1255                         kmem_free(mp->m_perag[agno].pagb_list,
1256                           sizeof(xfs_perag_busy_t) * XFS_PAGB_NUM_SLOTS);
1257         kmem_free(mp->m_perag, sbp->sb_agcount * sizeof(xfs_perag_t));
1258         mp->m_perag = NULL;
1259         /* FALLTHROUGH */
1260  error1:
1261         if (uuid_mounted)
1262                 xfs_uuid_unmount(mp);
1263         xfs_freesb(mp);
1264         return error;
1265 }
1266
1267 /*
1268  * xfs_unmountfs
1269  *
1270  * This flushes out the inodes,dquots and the superblock, unmounts the
1271  * log and makes sure that incore structures are freed.
1272  */
1273 int
1274 xfs_unmountfs(xfs_mount_t *mp, struct cred *cr)
1275 {
1276         __uint64_t      resblks;
1277
1278         /*
1279          * We can potentially deadlock here if we have an inode cluster
1280          * that has been freed has it's buffer still pinned in memory because
1281          * the transaction is still sitting in a iclog. The stale inodes
1282          * on that buffer will have their flush locks held until the
1283          * transaction hits the disk and the callbacks run. the inode
1284          * flush takes the flush lock unconditionally and with nothing to
1285          * push out the iclog we will never get that unlocked. hence we
1286          * need to force the log first.
1287          */
1288         xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE | XFS_LOG_SYNC);
1289         xfs_iflush_all(mp);
1290
1291         XFS_QM_DQPURGEALL(mp, XFS_QMOPT_QUOTALL | XFS_QMOPT_UMOUNTING);
1292
1293         /*
1294          * Flush out the log synchronously so that we know for sure
1295          * that nothing is pinned.  This is important because bflush()
1296          * will skip pinned buffers.
1297          */
1298         xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE | XFS_LOG_SYNC);
1299
1300         xfs_binval(mp->m_ddev_targp);
1301         if (mp->m_rtdev_targp) {
1302                 xfs_binval(mp->m_rtdev_targp);
1303         }
1304
1305         /*
1306          * Unreserve any blocks we have so that when we unmount we don't account
1307          * the reserved free space as used. This is really only necessary for
1308          * lazy superblock counting because it trusts the incore superblock
1309          * counters to be aboslutely correct on clean unmount.
1310          *
1311          * We don't bother correcting this elsewhere for lazy superblock
1312          * counting because on mount of an unclean filesystem we reconstruct the
1313          * correct counter value and this is irrelevant.
1314          *
1315          * For non-lazy counter filesystems, this doesn't matter at all because
1316          * we only every apply deltas to the superblock and hence the incore
1317          * value does not matter....
1318          */
1319         resblks = 0;
1320         xfs_reserve_blocks(mp, &resblks, NULL);
1321
1322         xfs_log_sbcount(mp, 1);
1323         xfs_unmountfs_writesb(mp);
1324         xfs_unmountfs_wait(mp);                 /* wait for async bufs */
1325         xfs_log_unmount(mp);                    /* Done! No more fs ops. */
1326
1327         xfs_freesb(mp);
1328
1329         /*
1330          * All inodes from this mount point should be freed.
1331          */
1332         ASSERT(mp->m_inodes == NULL);
1333
1334         xfs_unmountfs_close(mp, cr);
1335         if ((mp->m_flags & XFS_MOUNT_NOUUID) == 0)
1336                 xfs_uuid_unmount(mp);
1337
1338 #if defined(DEBUG) || defined(INDUCE_IO_ERROR)
1339         xfs_errortag_clearall(mp, 0);
1340 #endif
1341         xfs_mount_free(mp);
1342         return 0;
1343 }
1344
1345 void
1346 xfs_unmountfs_close(xfs_mount_t *mp, struct cred *cr)
1347 {
1348         if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp)
1349                 xfs_free_buftarg(mp->m_logdev_targp, 1);
1350         if (mp->m_rtdev_targp)
1351                 xfs_free_buftarg(mp->m_rtdev_targp, 1);
1352         xfs_free_buftarg(mp->m_ddev_targp, 0);
1353 }
1354
1355 STATIC void
1356 xfs_unmountfs_wait(xfs_mount_t *mp)
1357 {
1358         if (mp->m_logdev_targp != mp->m_ddev_targp)
1359                 xfs_wait_buftarg(mp->m_logdev_targp);
1360         if (mp->m_rtdev_targp)
1361                 xfs_wait_buftarg(mp->m_rtdev_targp);
1362         xfs_wait_buftarg(mp->m_ddev_targp);
1363 }
1364
1365 int
1366 xfs_fs_writable(xfs_mount_t *mp)
1367 {
1368         return !(xfs_test_for_freeze(mp) || XFS_FORCED_SHUTDOWN(mp) ||
1369                 (mp->m_flags & XFS_MOUNT_RDONLY));
1370 }
1371
1372 /*
1373  * xfs_log_sbcount
1374  *
1375  * Called either periodically to keep the on disk superblock values
1376  * roughly up to date or from unmount to make sure the values are
1377  * correct on a clean unmount.
1378  *
1379  * Note this code can be called during the process of freezing, so
1380  * we may need to use the transaction allocator which does not not
1381  * block when the transaction subsystem is in its frozen state.
1382  */
1383 int
1384 xfs_log_sbcount(
1385         xfs_mount_t     *mp,
1386         uint            sync)
1387 {
1388         xfs_trans_t     *tp;
1389         int             error;
1390
1391         if (!xfs_fs_writable(mp))
1392                 return 0;
1393
1394         xfs_icsb_sync_counters(mp);
1395
1396         /*
1397          * we don't need to do this if we are updating the superblock
1398          * counters on every modification.
1399          */
1400         if (!xfs_sb_version_haslazysbcount(&mp->m_sb))
1401                 return 0;
1402
1403         tp = _xfs_trans_alloc(mp, XFS_TRANS_SB_COUNT);
1404         error = xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0,
1405                                         XFS_DEFAULT_LOG_COUNT);
1406         if (error) {
1407                 xfs_trans_cancel(tp, 0);
1408                 return error;
1409         }
1410
1411         xfs_mod_sb(tp, XFS_SB_IFREE | XFS_SB_ICOUNT | XFS_SB_FDBLOCKS);
1412         if (sync)
1413                 xfs_trans_set_sync(tp);
1414         xfs_trans_commit(tp, 0);
1415
1416         return 0;
1417 }
1418
1419 STATIC void
1420 xfs_mark_shared_ro(
1421         xfs_mount_t     *mp,
1422         xfs_buf_t       *bp)
1423 {
1424         xfs_dsb_t       *sb = XFS_BUF_TO_SBP(bp);
1425         __uint16_t      version;
1426
1427         if (!(sb->sb_flags & XFS_SBF_READONLY))
1428                 sb->sb_flags |= XFS_SBF_READONLY;
1429
1430         version = be16_to_cpu(sb->sb_versionnum);
1431         if ((version & XFS_SB_VERSION_NUMBITS) != XFS_SB_VERSION_4 ||
1432             !(version & XFS_SB_VERSION_SHAREDBIT))
1433                 version |= XFS_SB_VERSION_SHAREDBIT;
1434         sb->sb_versionnum = cpu_to_be16(version);
1435 }
1436
1437 int
1438 xfs_unmountfs_writesb(xfs_mount_t *mp)
1439 {
1440         xfs_buf_t       *sbp;
1441         int             error = 0;
1442
1443         /*
1444          * skip superblock write if fs is read-only, or
1445          * if we are doing a forced umount.
1446          */
1447         if (!((mp->m_flags & XFS_MOUNT_RDONLY) ||
1448                 XFS_FORCED_SHUTDOWN(mp))) {
1449
1450                 sbp = xfs_getsb(mp, 0);
1451
1452                 /*
1453                  * mark shared-readonly if desired
1454                  */
1455                 if (mp->m_mk_sharedro)
1456                         xfs_mark_shared_ro(mp, sbp);
1457
1458                 XFS_BUF_UNDONE(sbp);
1459                 XFS_BUF_UNREAD(sbp);
1460                 XFS_BUF_UNDELAYWRITE(sbp);
1461                 XFS_BUF_WRITE(sbp);
1462                 XFS_BUF_UNASYNC(sbp);
1463                 ASSERT(XFS_BUF_TARGET(sbp) == mp->m_ddev_targp);
1464                 xfsbdstrat(mp, sbp);
1465                 /* Nevermind errors we might get here. */
1466                 error = xfs_iowait(sbp);
1467                 if (error)
1468                         xfs_ioerror_alert("xfs_unmountfs_writesb",
1469                                           mp, sbp, XFS_BUF_ADDR(sbp));
1470                 if (error && mp->m_mk_sharedro)
1471                         xfs_fs_cmn_err(CE_ALERT, mp, "Superblock write error detected while unmounting.  Filesystem may not be marked shared readonly");
1472                 xfs_buf_relse(sbp);
1473         }
1474         return error;
1475 }
1476
1477 /*
1478  * xfs_mod_sb() can be used to copy arbitrary changes to the
1479  * in-core superblock into the superblock buffer to be logged.
1480  * It does not provide the higher level of locking that is
1481  * needed to protect the in-core superblock from concurrent
1482  * access.
1483  */
1484 void
1485 xfs_mod_sb(xfs_trans_t *tp, __int64_t fields)
1486 {
1487         xfs_buf_t       *bp;
1488         int             first;
1489         int             last;
1490         xfs_mount_t     *mp;
1491         xfs_sb_field_t  f;
1492
1493         ASSERT(fields);
1494         if (!fields)
1495                 return;
1496         mp = tp->t_mountp;
1497         bp = xfs_trans_getsb(tp, mp, 0);
1498         first = sizeof(xfs_sb_t);
1499         last = 0;
1500
1501         /* translate/copy */
1502
1503         xfs_sb_to_disk(XFS_BUF_TO_SBP(bp), &mp->m_sb, fields);
1504
1505         /* find modified range */
1506
1507         f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
1508         ASSERT((1LL << f) & XFS_SB_MOD_BITS);
1509         first = xfs_sb_info[f].offset;
1510
1511         f = (xfs_sb_field_t)xfs_highbit64((__uint64_t)fields);
1512         ASSERT((1LL << f) & XFS_SB_MOD_BITS);
1513         last = xfs_sb_info[f + 1].offset - 1;
1514
1515         xfs_trans_log_buf(tp, bp, first, last);
1516 }
1517
1518
1519 /*
1520  * xfs_mod_incore_sb_unlocked() is a utility routine common used to apply
1521  * a delta to a specified field in the in-core superblock.  Simply
1522  * switch on the field indicated and apply the delta to that field.
1523  * Fields are not allowed to dip below zero, so if the delta would
1524  * do this do not apply it and return EINVAL.
1525  *
1526  * The m_sb_lock must be held when this routine is called.
1527  */
1528 int
1529 xfs_mod_incore_sb_unlocked(
1530         xfs_mount_t     *mp,
1531         xfs_sb_field_t  field,
1532         int64_t         delta,
1533         int             rsvd)
1534 {
1535         int             scounter;       /* short counter for 32 bit fields */
1536         long long       lcounter;       /* long counter for 64 bit fields */
1537         long long       res_used, rem;
1538
1539         /*
1540          * With the in-core superblock spin lock held, switch
1541          * on the indicated field.  Apply the delta to the
1542          * proper field.  If the fields value would dip below
1543          * 0, then do not apply the delta and return EINVAL.
1544          */
1545         switch (field) {
1546         case XFS_SBS_ICOUNT:
1547                 lcounter = (long long)mp->m_sb.sb_icount;
1548                 lcounter += delta;
1549                 if (lcounter < 0) {
1550                         ASSERT(0);
1551                         return XFS_ERROR(EINVAL);
1552                 }
1553                 mp->m_sb.sb_icount = lcounter;
1554                 return 0;
1555         case XFS_SBS_IFREE:
1556                 lcounter = (long long)mp->m_sb.sb_ifree;
1557                 lcounter += delta;
1558                 if (lcounter < 0) {
1559                         ASSERT(0);
1560                         return XFS_ERROR(EINVAL);
1561                 }
1562                 mp->m_sb.sb_ifree = lcounter;
1563                 return 0;
1564         case XFS_SBS_FDBLOCKS:
1565                 lcounter = (long long)
1566                         mp->m_sb.sb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
1567                 res_used = (long long)(mp->m_resblks - mp->m_resblks_avail);
1568
1569                 if (delta > 0) {                /* Putting blocks back */
1570                         if (res_used > delta) {
1571                                 mp->m_resblks_avail += delta;
1572                         } else {
1573                                 rem = delta - res_used;
1574                                 mp->m_resblks_avail = mp->m_resblks;
1575                                 lcounter += rem;
1576                         }
1577                 } else {                                /* Taking blocks away */
1578
1579                         lcounter += delta;
1580
1581                 /*
1582                  * If were out of blocks, use any available reserved blocks if
1583                  * were allowed to.
1584                  */
1585
1586                         if (lcounter < 0) {
1587                                 if (rsvd) {
1588                                         lcounter = (long long)mp->m_resblks_avail + delta;
1589                                         if (lcounter < 0) {
1590                                                 return XFS_ERROR(ENOSPC);
1591                                         }
1592                                         mp->m_resblks_avail = lcounter;
1593                                         return 0;
1594                                 } else {        /* not reserved */
1595                                         return XFS_ERROR(ENOSPC);
1596                                 }
1597                         }
1598                 }
1599
1600                 mp->m_sb.sb_fdblocks = lcounter + XFS_ALLOC_SET_ASIDE(mp);
1601                 return 0;
1602         case XFS_SBS_FREXTENTS:
1603                 lcounter = (long long)mp->m_sb.sb_frextents;
1604                 lcounter += delta;
1605                 if (lcounter < 0) {
1606                         return XFS_ERROR(ENOSPC);
1607                 }
1608                 mp->m_sb.sb_frextents = lcounter;
1609                 return 0;
1610         case XFS_SBS_DBLOCKS:
1611                 lcounter = (long long)mp->m_sb.sb_dblocks;
1612                 lcounter += delta;
1613                 if (lcounter < 0) {
1614                         ASSERT(0);
1615                         return XFS_ERROR(EINVAL);
1616                 }
1617                 mp->m_sb.sb_dblocks = lcounter;
1618                 return 0;
1619         case XFS_SBS_AGCOUNT:
1620                 scounter = mp->m_sb.sb_agcount;
1621                 scounter += delta;
1622                 if (scounter < 0) {
1623                         ASSERT(0);
1624                         return XFS_ERROR(EINVAL);
1625                 }
1626                 mp->m_sb.sb_agcount = scounter;
1627                 return 0;
1628         case XFS_SBS_IMAX_PCT:
1629                 scounter = mp->m_sb.sb_imax_pct;
1630                 scounter += delta;
1631                 if (scounter < 0) {
1632                         ASSERT(0);
1633                         return XFS_ERROR(EINVAL);
1634                 }
1635                 mp->m_sb.sb_imax_pct = scounter;
1636                 return 0;
1637         case XFS_SBS_REXTSIZE:
1638                 scounter = mp->m_sb.sb_rextsize;
1639                 scounter += delta;
1640                 if (scounter < 0) {
1641                         ASSERT(0);
1642                         return XFS_ERROR(EINVAL);
1643                 }
1644                 mp->m_sb.sb_rextsize = scounter;
1645                 return 0;
1646         case XFS_SBS_RBMBLOCKS:
1647                 scounter = mp->m_sb.sb_rbmblocks;
1648                 scounter += delta;
1649                 if (scounter < 0) {
1650                         ASSERT(0);
1651                         return XFS_ERROR(EINVAL);
1652                 }
1653                 mp->m_sb.sb_rbmblocks = scounter;
1654                 return 0;
1655         case XFS_SBS_RBLOCKS:
1656                 lcounter = (long long)mp->m_sb.sb_rblocks;
1657                 lcounter += delta;
1658                 if (lcounter < 0) {
1659                         ASSERT(0);
1660                         return XFS_ERROR(EINVAL);
1661                 }
1662                 mp->m_sb.sb_rblocks = lcounter;
1663                 return 0;
1664         case XFS_SBS_REXTENTS:
1665                 lcounter = (long long)mp->m_sb.sb_rextents;
1666                 lcounter += delta;
1667                 if (lcounter < 0) {
1668                         ASSERT(0);
1669                         return XFS_ERROR(EINVAL);
1670                 }
1671                 mp->m_sb.sb_rextents = lcounter;
1672                 return 0;
1673         case XFS_SBS_REXTSLOG:
1674                 scounter = mp->m_sb.sb_rextslog;
1675                 scounter += delta;
1676                 if (scounter < 0) {
1677                         ASSERT(0);
1678                         return XFS_ERROR(EINVAL);
1679                 }
1680                 mp->m_sb.sb_rextslog = scounter;
1681                 return 0;
1682         default:
1683                 ASSERT(0);
1684                 return XFS_ERROR(EINVAL);
1685         }
1686 }
1687
1688 /*
1689  * xfs_mod_incore_sb() is used to change a field in the in-core
1690  * superblock structure by the specified delta.  This modification
1691  * is protected by the m_sb_lock.  Just use the xfs_mod_incore_sb_unlocked()
1692  * routine to do the work.
1693  */
1694 int
1695 xfs_mod_incore_sb(
1696         xfs_mount_t     *mp,
1697         xfs_sb_field_t  field,
1698         int64_t         delta,
1699         int             rsvd)
1700 {
1701         int     status;
1702
1703         /* check for per-cpu counters */
1704         switch (field) {
1705 #ifdef HAVE_PERCPU_SB
1706         case XFS_SBS_ICOUNT:
1707         case XFS_SBS_IFREE:
1708         case XFS_SBS_FDBLOCKS:
1709                 if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1710                         status = xfs_icsb_modify_counters(mp, field,
1711                                                         delta, rsvd);
1712                         break;
1713                 }
1714                 /* FALLTHROUGH */
1715 #endif
1716         default:
1717                 spin_lock(&mp->m_sb_lock);
1718                 status = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
1719                 spin_unlock(&mp->m_sb_lock);
1720                 break;
1721         }
1722
1723         return status;
1724 }
1725
1726 /*
1727  * xfs_mod_incore_sb_batch() is used to change more than one field
1728  * in the in-core superblock structure at a time.  This modification
1729  * is protected by a lock internal to this module.  The fields and
1730  * changes to those fields are specified in the array of xfs_mod_sb
1731  * structures passed in.
1732  *
1733  * Either all of the specified deltas will be applied or none of
1734  * them will.  If any modified field dips below 0, then all modifications
1735  * will be backed out and EINVAL will be returned.
1736  */
1737 int
1738 xfs_mod_incore_sb_batch(xfs_mount_t *mp, xfs_mod_sb_t *msb, uint nmsb, int rsvd)
1739 {
1740         int             status=0;
1741         xfs_mod_sb_t    *msbp;
1742
1743         /*
1744          * Loop through the array of mod structures and apply each
1745          * individually.  If any fail, then back out all those
1746          * which have already been applied.  Do all of this within
1747          * the scope of the m_sb_lock so that all of the changes will
1748          * be atomic.
1749          */
1750         spin_lock(&mp->m_sb_lock);
1751         msbp = &msb[0];
1752         for (msbp = &msbp[0]; msbp < (msb + nmsb); msbp++) {
1753                 /*
1754                  * Apply the delta at index n.  If it fails, break
1755                  * from the loop so we'll fall into the undo loop
1756                  * below.
1757                  */
1758                 switch (msbp->msb_field) {
1759 #ifdef HAVE_PERCPU_SB
1760                 case XFS_SBS_ICOUNT:
1761                 case XFS_SBS_IFREE:
1762                 case XFS_SBS_FDBLOCKS:
1763                         if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1764                                 spin_unlock(&mp->m_sb_lock);
1765                                 status = xfs_icsb_modify_counters(mp,
1766                                                         msbp->msb_field,
1767                                                         msbp->msb_delta, rsvd);
1768                                 spin_lock(&mp->m_sb_lock);
1769                                 break;
1770                         }
1771                         /* FALLTHROUGH */
1772 #endif
1773                 default:
1774                         status = xfs_mod_incore_sb_unlocked(mp,
1775                                                 msbp->msb_field,
1776                                                 msbp->msb_delta, rsvd);
1777                         break;
1778                 }
1779
1780                 if (status != 0) {
1781                         break;
1782                 }
1783         }
1784
1785         /*
1786          * If we didn't complete the loop above, then back out
1787          * any changes made to the superblock.  If you add code
1788          * between the loop above and here, make sure that you
1789          * preserve the value of status. Loop back until
1790          * we step below the beginning of the array.  Make sure
1791          * we don't touch anything back there.
1792          */
1793         if (status != 0) {
1794                 msbp--;
1795                 while (msbp >= msb) {
1796                         switch (msbp->msb_field) {
1797 #ifdef HAVE_PERCPU_SB
1798                         case XFS_SBS_ICOUNT:
1799                         case XFS_SBS_IFREE:
1800                         case XFS_SBS_FDBLOCKS:
1801                                 if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1802                                         spin_unlock(&mp->m_sb_lock);
1803                                         status = xfs_icsb_modify_counters(mp,
1804                                                         msbp->msb_field,
1805                                                         -(msbp->msb_delta),
1806                                                         rsvd);
1807                                         spin_lock(&mp->m_sb_lock);
1808                                         break;
1809                                 }
1810                                 /* FALLTHROUGH */
1811 #endif
1812                         default:
1813                                 status = xfs_mod_incore_sb_unlocked(mp,
1814                                                         msbp->msb_field,
1815                                                         -(msbp->msb_delta),
1816                                                         rsvd);
1817                                 break;
1818                         }
1819                         ASSERT(status == 0);
1820                         msbp--;
1821                 }
1822         }
1823         spin_unlock(&mp->m_sb_lock);
1824         return status;
1825 }
1826
1827 /*
1828  * xfs_getsb() is called to obtain the buffer for the superblock.
1829  * The buffer is returned locked and read in from disk.
1830  * The buffer should be released with a call to xfs_brelse().
1831  *
1832  * If the flags parameter is BUF_TRYLOCK, then we'll only return
1833  * the superblock buffer if it can be locked without sleeping.
1834  * If it can't then we'll return NULL.
1835  */
1836 xfs_buf_t *
1837 xfs_getsb(
1838         xfs_mount_t     *mp,
1839         int             flags)
1840 {
1841         xfs_buf_t       *bp;
1842
1843         ASSERT(mp->m_sb_bp != NULL);
1844         bp = mp->m_sb_bp;
1845         if (flags & XFS_BUF_TRYLOCK) {
1846                 if (!XFS_BUF_CPSEMA(bp)) {
1847                         return NULL;
1848                 }
1849         } else {
1850                 XFS_BUF_PSEMA(bp, PRIBIO);
1851         }
1852         XFS_BUF_HOLD(bp);
1853         ASSERT(XFS_BUF_ISDONE(bp));
1854         return bp;
1855 }
1856
1857 /*
1858  * Used to free the superblock along various error paths.
1859  */
1860 void
1861 xfs_freesb(
1862         xfs_mount_t     *mp)
1863 {
1864         xfs_buf_t       *bp;
1865
1866         /*
1867          * Use xfs_getsb() so that the buffer will be locked
1868          * when we call xfs_buf_relse().
1869          */
1870         bp = xfs_getsb(mp, 0);
1871         XFS_BUF_UNMANAGE(bp);
1872         xfs_buf_relse(bp);
1873         mp->m_sb_bp = NULL;
1874 }
1875
1876 /*
1877  * See if the UUID is unique among mounted XFS filesystems.
1878  * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
1879  */
1880 STATIC int
1881 xfs_uuid_mount(
1882         xfs_mount_t     *mp)
1883 {
1884         if (uuid_is_nil(&mp->m_sb.sb_uuid)) {
1885                 cmn_err(CE_WARN,
1886                         "XFS: Filesystem %s has nil UUID - can't mount",
1887                         mp->m_fsname);
1888                 return -1;
1889         }
1890         if (!uuid_table_insert(&mp->m_sb.sb_uuid)) {
1891                 cmn_err(CE_WARN,
1892                         "XFS: Filesystem %s has duplicate UUID - can't mount",
1893                         mp->m_fsname);
1894                 return -1;
1895         }
1896         return 0;
1897 }
1898
1899 /*
1900  * Remove filesystem from the UUID table.
1901  */
1902 STATIC void
1903 xfs_uuid_unmount(
1904         xfs_mount_t     *mp)
1905 {
1906         uuid_table_remove(&mp->m_sb.sb_uuid);
1907 }
1908
1909 /*
1910  * Used to log changes to the superblock unit and width fields which could
1911  * be altered by the mount options, as well as any potential sb_features2
1912  * fixup. Only the first superblock is updated.
1913  */
1914 STATIC void
1915 xfs_mount_log_sb(
1916         xfs_mount_t     *mp,
1917         __int64_t       fields)
1918 {
1919         xfs_trans_t     *tp;
1920
1921         ASSERT(fields & (XFS_SB_UNIT | XFS_SB_WIDTH | XFS_SB_UUID |
1922                          XFS_SB_FEATURES2 | XFS_SB_BAD_FEATURES2));
1923
1924         tp = xfs_trans_alloc(mp, XFS_TRANS_SB_UNIT);
1925         if (xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0,
1926                                 XFS_DEFAULT_LOG_COUNT)) {
1927                 xfs_trans_cancel(tp, 0);
1928                 return;
1929         }
1930         xfs_mod_sb(tp, fields);
1931         xfs_trans_commit(tp, 0);
1932 }
1933
1934
1935 #ifdef HAVE_PERCPU_SB
1936 /*
1937  * Per-cpu incore superblock counters
1938  *
1939  * Simple concept, difficult implementation
1940  *
1941  * Basically, replace the incore superblock counters with a distributed per cpu
1942  * counter for contended fields (e.g.  free block count).
1943  *
1944  * Difficulties arise in that the incore sb is used for ENOSPC checking, and
1945  * hence needs to be accurately read when we are running low on space. Hence
1946  * there is a method to enable and disable the per-cpu counters based on how
1947  * much "stuff" is available in them.
1948  *
1949  * Basically, a counter is enabled if there is enough free resource to justify
1950  * running a per-cpu fast-path. If the per-cpu counter runs out (i.e. a local
1951  * ENOSPC), then we disable the counters to synchronise all callers and
1952  * re-distribute the available resources.
1953  *
1954  * If, once we redistributed the available resources, we still get a failure,
1955  * we disable the per-cpu counter and go through the slow path.
1956  *
1957  * The slow path is the current xfs_mod_incore_sb() function.  This means that
1958  * when we disable a per-cpu counter, we need to drain it's resources back to
1959  * the global superblock. We do this after disabling the counter to prevent
1960  * more threads from queueing up on the counter.
1961  *
1962  * Essentially, this means that we still need a lock in the fast path to enable
1963  * synchronisation between the global counters and the per-cpu counters. This
1964  * is not a problem because the lock will be local to a CPU almost all the time
1965  * and have little contention except when we get to ENOSPC conditions.
1966  *
1967  * Basically, this lock becomes a barrier that enables us to lock out the fast
1968  * path while we do things like enabling and disabling counters and
1969  * synchronising the counters.
1970  *
1971  * Locking rules:
1972  *
1973  *      1. m_sb_lock before picking up per-cpu locks
1974  *      2. per-cpu locks always picked up via for_each_online_cpu() order
1975  *      3. accurate counter sync requires m_sb_lock + per cpu locks
1976  *      4. modifying per-cpu counters requires holding per-cpu lock
1977  *      5. modifying global counters requires holding m_sb_lock
1978  *      6. enabling or disabling a counter requires holding the m_sb_lock 
1979  *         and _none_ of the per-cpu locks.
1980  *
1981  * Disabled counters are only ever re-enabled by a balance operation
1982  * that results in more free resources per CPU than a given threshold.
1983  * To ensure counters don't remain disabled, they are rebalanced when
1984  * the global resource goes above a higher threshold (i.e. some hysteresis
1985  * is present to prevent thrashing).
1986  */
1987
1988 #ifdef CONFIG_HOTPLUG_CPU
1989 /*
1990  * hot-plug CPU notifier support.
1991  *
1992  * We need a notifier per filesystem as we need to be able to identify
1993  * the filesystem to balance the counters out. This is achieved by
1994  * having a notifier block embedded in the xfs_mount_t and doing pointer
1995  * magic to get the mount pointer from the notifier block address.
1996  */
1997 STATIC int
1998 xfs_icsb_cpu_notify(
1999         struct notifier_block *nfb,
2000         unsigned long action,
2001         void *hcpu)
2002 {
2003         xfs_icsb_cnts_t *cntp;
2004         xfs_mount_t     *mp;
2005
2006         mp = (xfs_mount_t *)container_of(nfb, xfs_mount_t, m_icsb_notifier);
2007         cntp = (xfs_icsb_cnts_t *)
2008                         per_cpu_ptr(mp->m_sb_cnts, (unsigned long)hcpu);
2009         switch (action) {
2010         case CPU_UP_PREPARE:
2011         case CPU_UP_PREPARE_FROZEN:
2012                 /* Easy Case - initialize the area and locks, and
2013                  * then rebalance when online does everything else for us. */
2014                 memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
2015                 break;
2016         case CPU_ONLINE:
2017         case CPU_ONLINE_FROZEN:
2018                 xfs_icsb_lock(mp);
2019                 xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0, 0);
2020                 xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0, 0);
2021                 xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0, 0);
2022                 xfs_icsb_unlock(mp);
2023                 break;
2024         case CPU_DEAD:
2025         case CPU_DEAD_FROZEN:
2026                 /* Disable all the counters, then fold the dead cpu's
2027                  * count into the total on the global superblock and
2028                  * re-enable the counters. */
2029                 xfs_icsb_lock(mp);
2030                 spin_lock(&mp->m_sb_lock);
2031                 xfs_icsb_disable_counter(mp, XFS_SBS_ICOUNT);
2032                 xfs_icsb_disable_counter(mp, XFS_SBS_IFREE);
2033                 xfs_icsb_disable_counter(mp, XFS_SBS_FDBLOCKS);
2034
2035                 mp->m_sb.sb_icount += cntp->icsb_icount;
2036                 mp->m_sb.sb_ifree += cntp->icsb_ifree;
2037                 mp->m_sb.sb_fdblocks += cntp->icsb_fdblocks;
2038
2039                 memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
2040
2041                 xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT,
2042                                          XFS_ICSB_SB_LOCKED, 0);
2043                 xfs_icsb_balance_counter(mp, XFS_SBS_IFREE,
2044                                          XFS_ICSB_SB_LOCKED, 0);
2045                 xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS,
2046                                          XFS_ICSB_SB_LOCKED, 0);
2047                 spin_unlock(&mp->m_sb_lock);
2048                 xfs_icsb_unlock(mp);
2049                 break;
2050         }
2051
2052         return NOTIFY_OK;
2053 }
2054 #endif /* CONFIG_HOTPLUG_CPU */
2055
2056 int
2057 xfs_icsb_init_counters(
2058         xfs_mount_t     *mp)
2059 {
2060         xfs_icsb_cnts_t *cntp;
2061         int             i;
2062
2063         mp->m_sb_cnts = alloc_percpu(xfs_icsb_cnts_t);
2064         if (mp->m_sb_cnts == NULL)
2065                 return -ENOMEM;
2066
2067 #ifdef CONFIG_HOTPLUG_CPU
2068         mp->m_icsb_notifier.notifier_call = xfs_icsb_cpu_notify;
2069         mp->m_icsb_notifier.priority = 0;
2070         register_hotcpu_notifier(&mp->m_icsb_notifier);
2071 #endif /* CONFIG_HOTPLUG_CPU */
2072
2073         for_each_online_cpu(i) {
2074                 cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
2075                 memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
2076         }
2077
2078         mutex_init(&mp->m_icsb_mutex);
2079
2080         /*
2081          * start with all counters disabled so that the
2082          * initial balance kicks us off correctly
2083          */
2084         mp->m_icsb_counters = -1;
2085         return 0;
2086 }
2087
2088 void
2089 xfs_icsb_reinit_counters(
2090         xfs_mount_t     *mp)
2091 {
2092         xfs_icsb_lock(mp);
2093         /*
2094          * start with all counters disabled so that the
2095          * initial balance kicks us off correctly
2096          */
2097         mp->m_icsb_counters = -1;
2098         xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0, 0);
2099         xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0, 0);
2100         xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0, 0);
2101         xfs_icsb_unlock(mp);
2102 }
2103
2104 STATIC void
2105 xfs_icsb_destroy_counters(
2106         xfs_mount_t     *mp)
2107 {
2108         if (mp->m_sb_cnts) {
2109                 unregister_hotcpu_notifier(&mp->m_icsb_notifier);
2110                 free_percpu(mp->m_sb_cnts);
2111         }
2112         mutex_destroy(&mp->m_icsb_mutex);
2113 }
2114
2115 STATIC_INLINE void
2116 xfs_icsb_lock_cntr(
2117         xfs_icsb_cnts_t *icsbp)
2118 {
2119         while (test_and_set_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags)) {
2120                 ndelay(1000);
2121         }
2122 }
2123
2124 STATIC_INLINE void
2125 xfs_icsb_unlock_cntr(
2126         xfs_icsb_cnts_t *icsbp)
2127 {
2128         clear_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags);
2129 }
2130
2131
2132 STATIC_INLINE void
2133 xfs_icsb_lock_all_counters(
2134         xfs_mount_t     *mp)
2135 {
2136         xfs_icsb_cnts_t *cntp;
2137         int             i;
2138
2139         for_each_online_cpu(i) {
2140                 cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
2141                 xfs_icsb_lock_cntr(cntp);
2142         }
2143 }
2144
2145 STATIC_INLINE void
2146 xfs_icsb_unlock_all_counters(
2147         xfs_mount_t     *mp)
2148 {
2149         xfs_icsb_cnts_t *cntp;
2150         int             i;
2151
2152         for_each_online_cpu(i) {
2153                 cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
2154                 xfs_icsb_unlock_cntr(cntp);
2155         }
2156 }
2157
2158 STATIC void
2159 xfs_icsb_count(
2160         xfs_mount_t     *mp,
2161         xfs_icsb_cnts_t *cnt,
2162         int             flags)
2163 {
2164         xfs_icsb_cnts_t *cntp;
2165         int             i;
2166
2167         memset(cnt, 0, sizeof(xfs_icsb_cnts_t));
2168
2169         if (!(flags & XFS_ICSB_LAZY_COUNT))
2170                 xfs_icsb_lock_all_counters(mp);
2171
2172         for_each_online_cpu(i) {
2173                 cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
2174                 cnt->icsb_icount += cntp->icsb_icount;
2175                 cnt->icsb_ifree += cntp->icsb_ifree;
2176                 cnt->icsb_fdblocks += cntp->icsb_fdblocks;
2177         }
2178
2179         if (!(flags & XFS_ICSB_LAZY_COUNT))
2180                 xfs_icsb_unlock_all_counters(mp);
2181 }
2182
2183 STATIC int
2184 xfs_icsb_counter_disabled(
2185         xfs_mount_t     *mp,
2186         xfs_sb_field_t  field)
2187 {
2188         ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
2189         return test_bit(field, &mp->m_icsb_counters);
2190 }
2191
2192 STATIC int
2193 xfs_icsb_disable_counter(
2194         xfs_mount_t     *mp,
2195         xfs_sb_field_t  field)
2196 {
2197         xfs_icsb_cnts_t cnt;
2198
2199         ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
2200
2201         /*
2202          * If we are already disabled, then there is nothing to do
2203          * here. We check before locking all the counters to avoid
2204          * the expensive lock operation when being called in the
2205          * slow path and the counter is already disabled. This is
2206          * safe because the only time we set or clear this state is under
2207          * the m_icsb_mutex.
2208          */
2209         if (xfs_icsb_counter_disabled(mp, field))
2210                 return 0;
2211
2212         xfs_icsb_lock_all_counters(mp);
2213         if (!test_and_set_bit(field, &mp->m_icsb_counters)) {
2214                 /* drain back to superblock */
2215
2216                 xfs_icsb_count(mp, &cnt, XFS_ICSB_SB_LOCKED|XFS_ICSB_LAZY_COUNT);
2217                 switch(field) {
2218                 case XFS_SBS_ICOUNT:
2219                         mp->m_sb.sb_icount = cnt.icsb_icount;
2220                         break;
2221                 case XFS_SBS_IFREE:
2222                         mp->m_sb.sb_ifree = cnt.icsb_ifree;
2223                         break;
2224                 case XFS_SBS_FDBLOCKS:
2225                         mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
2226                         break;
2227                 default:
2228                         BUG();
2229                 }
2230         }
2231
2232         xfs_icsb_unlock_all_counters(mp);
2233
2234         return 0;
2235 }
2236
2237 STATIC void
2238 xfs_icsb_enable_counter(
2239         xfs_mount_t     *mp,
2240         xfs_sb_field_t  field,
2241         uint64_t        count,
2242         uint64_t        resid)
2243 {
2244         xfs_icsb_cnts_t *cntp;
2245         int             i;
2246
2247         ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
2248
2249         xfs_icsb_lock_all_counters(mp);
2250         for_each_online_cpu(i) {
2251                 cntp = per_cpu_ptr(mp->m_sb_cnts, i);
2252                 switch (field) {
2253                 case XFS_SBS_ICOUNT:
2254                         cntp->icsb_icount = count + resid;
2255                         break;
2256                 case XFS_SBS_IFREE:
2257                         cntp->icsb_ifree = count + resid;
2258                         break;
2259                 case XFS_SBS_FDBLOCKS:
2260                         cntp->icsb_fdblocks = count + resid;
2261                         break;
2262                 default:
2263                         BUG();
2264                         break;
2265                 }
2266                 resid = 0;
2267         }
2268         clear_bit(field, &mp->m_icsb_counters);
2269         xfs_icsb_unlock_all_counters(mp);
2270 }
2271
2272 void
2273 xfs_icsb_sync_counters_flags(
2274         xfs_mount_t     *mp,
2275         int             flags)
2276 {
2277         xfs_icsb_cnts_t cnt;
2278
2279         /* Pass 1: lock all counters */
2280         if ((flags & XFS_ICSB_SB_LOCKED) == 0)
2281                 spin_lock(&mp->m_sb_lock);
2282
2283         xfs_icsb_count(mp, &cnt, flags);
2284
2285         /* Step 3: update mp->m_sb fields */
2286         if (!xfs_icsb_counter_disabled(mp, XFS_SBS_ICOUNT))
2287                 mp->m_sb.sb_icount = cnt.icsb_icount;
2288         if (!xfs_icsb_counter_disabled(mp, XFS_SBS_IFREE))
2289                 mp->m_sb.sb_ifree = cnt.icsb_ifree;
2290         if (!xfs_icsb_counter_disabled(mp, XFS_SBS_FDBLOCKS))
2291                 mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
2292
2293         if ((flags & XFS_ICSB_SB_LOCKED) == 0)
2294                 spin_unlock(&mp->m_sb_lock);
2295 }
2296
2297 /*
2298  * Accurate update of per-cpu counters to incore superblock
2299  */
2300 STATIC void
2301 xfs_icsb_sync_counters(
2302         xfs_mount_t     *mp)
2303 {
2304         xfs_icsb_sync_counters_flags(mp, 0);
2305 }
2306
2307 /*
2308  * Balance and enable/disable counters as necessary.
2309  *
2310  * Thresholds for re-enabling counters are somewhat magic.  inode counts are
2311  * chosen to be the same number as single on disk allocation chunk per CPU, and
2312  * free blocks is something far enough zero that we aren't going thrash when we
2313  * get near ENOSPC. We also need to supply a minimum we require per cpu to
2314  * prevent looping endlessly when xfs_alloc_space asks for more than will
2315  * be distributed to a single CPU but each CPU has enough blocks to be
2316  * reenabled.
2317  *
2318  * Note that we can be called when counters are already disabled.
2319  * xfs_icsb_disable_counter() optimises the counter locking in this case to
2320  * prevent locking every per-cpu counter needlessly.
2321  */
2322
2323 #define XFS_ICSB_INO_CNTR_REENABLE      (uint64_t)64
2324 #define XFS_ICSB_FDBLK_CNTR_REENABLE(mp) \
2325                 (uint64_t)(512 + XFS_ALLOC_SET_ASIDE(mp))
2326 STATIC void
2327 xfs_icsb_balance_counter(
2328         xfs_mount_t     *mp,
2329         xfs_sb_field_t  field,
2330         int             flags,
2331         int             min_per_cpu)
2332 {
2333         uint64_t        count, resid;
2334         int             weight = num_online_cpus();
2335         uint64_t        min = (uint64_t)min_per_cpu;
2336
2337         if (!(flags & XFS_ICSB_SB_LOCKED))
2338                 spin_lock(&mp->m_sb_lock);
2339
2340         /* disable counter and sync counter */
2341         xfs_icsb_disable_counter(mp, field);
2342
2343         /* update counters  - first CPU gets residual*/
2344         switch (field) {
2345         case XFS_SBS_ICOUNT:
2346                 count = mp->m_sb.sb_icount;
2347                 resid = do_div(count, weight);
2348                 if (count < max(min, XFS_ICSB_INO_CNTR_REENABLE))
2349                         goto out;
2350                 break;
2351         case XFS_SBS_IFREE:
2352                 count = mp->m_sb.sb_ifree;
2353                 resid = do_div(count, weight);
2354                 if (count < max(min, XFS_ICSB_INO_CNTR_REENABLE))
2355                         goto out;
2356                 break;
2357         case XFS_SBS_FDBLOCKS:
2358                 count = mp->m_sb.sb_fdblocks;
2359                 resid = do_div(count, weight);
2360                 if (count < max(min, XFS_ICSB_FDBLK_CNTR_REENABLE(mp)))
2361                         goto out;
2362                 break;
2363         default:
2364                 BUG();
2365                 count = resid = 0;      /* quiet, gcc */
2366                 break;
2367         }
2368
2369         xfs_icsb_enable_counter(mp, field, count, resid);
2370 out:
2371         if (!(flags & XFS_ICSB_SB_LOCKED))
2372                 spin_unlock(&mp->m_sb_lock);
2373 }
2374
2375 STATIC int
2376 xfs_icsb_modify_counters(
2377         xfs_mount_t     *mp,
2378         xfs_sb_field_t  field,
2379         int64_t         delta,
2380         int             rsvd)
2381 {
2382         xfs_icsb_cnts_t *icsbp;
2383         long long       lcounter;       /* long counter for 64 bit fields */
2384         int             cpu, ret = 0;
2385
2386         might_sleep();
2387 again:
2388         cpu = get_cpu();
2389         icsbp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, cpu);
2390
2391         /*
2392          * if the counter is disabled, go to slow path
2393          */
2394         if (unlikely(xfs_icsb_counter_disabled(mp, field)))
2395                 goto slow_path;
2396         xfs_icsb_lock_cntr(icsbp);
2397         if (unlikely(xfs_icsb_counter_disabled(mp, field))) {
2398                 xfs_icsb_unlock_cntr(icsbp);
2399                 goto slow_path;
2400         }
2401
2402         switch (field) {
2403         case XFS_SBS_ICOUNT:
2404                 lcounter = icsbp->icsb_icount;
2405                 lcounter += delta;
2406                 if (unlikely(lcounter < 0))
2407                         goto balance_counter;
2408                 icsbp->icsb_icount = lcounter;
2409                 break;
2410
2411         case XFS_SBS_IFREE:
2412                 lcounter = icsbp->icsb_ifree;
2413                 lcounter += delta;
2414                 if (unlikely(lcounter < 0))
2415                         goto balance_counter;
2416                 icsbp->icsb_ifree = lcounter;
2417                 break;
2418
2419         case XFS_SBS_FDBLOCKS:
2420                 BUG_ON((mp->m_resblks - mp->m_resblks_avail) != 0);
2421
2422                 lcounter = icsbp->icsb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
2423                 lcounter += delta;
2424                 if (unlikely(lcounter < 0))
2425                         goto balance_counter;
2426                 icsbp->icsb_fdblocks = lcounter + XFS_ALLOC_SET_ASIDE(mp);
2427                 break;
2428         default:
2429                 BUG();
2430                 break;
2431         }
2432         xfs_icsb_unlock_cntr(icsbp);
2433         put_cpu();
2434         return 0;
2435
2436 slow_path:
2437         put_cpu();
2438
2439         /*
2440          * serialise with a mutex so we don't burn lots of cpu on
2441          * the superblock lock. We still need to hold the superblock
2442          * lock, however, when we modify the global structures.
2443          */
2444         xfs_icsb_lock(mp);
2445
2446         /*
2447          * Now running atomically.
2448          *
2449          * If the counter is enabled, someone has beaten us to rebalancing.
2450          * Drop the lock and try again in the fast path....
2451          */
2452         if (!(xfs_icsb_counter_disabled(mp, field))) {
2453                 xfs_icsb_unlock(mp);
2454                 goto again;
2455         }
2456
2457         /*
2458          * The counter is currently disabled. Because we are
2459          * running atomically here, we know a rebalance cannot
2460          * be in progress. Hence we can go straight to operating
2461          * on the global superblock. We do not call xfs_mod_incore_sb()
2462          * here even though we need to get the m_sb_lock. Doing so
2463          * will cause us to re-enter this function and deadlock.
2464          * Hence we get the m_sb_lock ourselves and then call
2465          * xfs_mod_incore_sb_unlocked() as the unlocked path operates
2466          * directly on the global counters.
2467          */
2468         spin_lock(&mp->m_sb_lock);
2469         ret = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
2470         spin_unlock(&mp->m_sb_lock);
2471
2472         /*
2473          * Now that we've modified the global superblock, we
2474          * may be able to re-enable the distributed counters
2475          * (e.g. lots of space just got freed). After that
2476          * we are done.
2477          */
2478         if (ret != ENOSPC)
2479                 xfs_icsb_balance_counter(mp, field, 0, 0);
2480         xfs_icsb_unlock(mp);
2481         return ret;
2482
2483 balance_counter:
2484         xfs_icsb_unlock_cntr(icsbp);
2485         put_cpu();
2486
2487         /*
2488          * We may have multiple threads here if multiple per-cpu
2489          * counters run dry at the same time. This will mean we can
2490          * do more balances than strictly necessary but it is not
2491          * the common slowpath case.
2492          */
2493         xfs_icsb_lock(mp);
2494
2495         /*
2496          * running atomically.
2497          *
2498          * This will leave the counter in the correct state for future
2499          * accesses. After the rebalance, we simply try again and our retry
2500          * will either succeed through the fast path or slow path without
2501          * another balance operation being required.
2502          */
2503         xfs_icsb_balance_counter(mp, field, 0, delta);
2504         xfs_icsb_unlock(mp);
2505         goto again;
2506 }
2507
2508 #endif