2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
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.
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.
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
20 #include "xfs_types.h"
24 #include "xfs_trans.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"
42 #include "xfs_error.h"
44 #include "xfs_quota.h"
45 #include "xfs_fsops.h"
46 #include "xfs_utils.h"
48 STATIC int xfs_uuid_mount(xfs_mount_t *);
49 STATIC void xfs_unmountfs_wait(xfs_mount_t *);
53 STATIC void xfs_icsb_balance_counter(xfs_mount_t *, xfs_sb_field_t,
55 STATIC void xfs_icsb_balance_counter_locked(xfs_mount_t *, xfs_sb_field_t,
57 STATIC int xfs_icsb_modify_counters(xfs_mount_t *, xfs_sb_field_t,
59 STATIC void xfs_icsb_disable_counter(xfs_mount_t *, xfs_sb_field_t);
63 #define xfs_icsb_balance_counter(mp, a, b) do { } while (0)
64 #define xfs_icsb_balance_counter_locked(mp, a, b) do { } while (0)
65 #define xfs_icsb_modify_counters(mp, a, b, c) do { } while (0)
71 short type; /* 0 = integer
72 * 1 = binary / string (no translation)
75 { offsetof(xfs_sb_t, sb_magicnum), 0 },
76 { offsetof(xfs_sb_t, sb_blocksize), 0 },
77 { offsetof(xfs_sb_t, sb_dblocks), 0 },
78 { offsetof(xfs_sb_t, sb_rblocks), 0 },
79 { offsetof(xfs_sb_t, sb_rextents), 0 },
80 { offsetof(xfs_sb_t, sb_uuid), 1 },
81 { offsetof(xfs_sb_t, sb_logstart), 0 },
82 { offsetof(xfs_sb_t, sb_rootino), 0 },
83 { offsetof(xfs_sb_t, sb_rbmino), 0 },
84 { offsetof(xfs_sb_t, sb_rsumino), 0 },
85 { offsetof(xfs_sb_t, sb_rextsize), 0 },
86 { offsetof(xfs_sb_t, sb_agblocks), 0 },
87 { offsetof(xfs_sb_t, sb_agcount), 0 },
88 { offsetof(xfs_sb_t, sb_rbmblocks), 0 },
89 { offsetof(xfs_sb_t, sb_logblocks), 0 },
90 { offsetof(xfs_sb_t, sb_versionnum), 0 },
91 { offsetof(xfs_sb_t, sb_sectsize), 0 },
92 { offsetof(xfs_sb_t, sb_inodesize), 0 },
93 { offsetof(xfs_sb_t, sb_inopblock), 0 },
94 { offsetof(xfs_sb_t, sb_fname[0]), 1 },
95 { offsetof(xfs_sb_t, sb_blocklog), 0 },
96 { offsetof(xfs_sb_t, sb_sectlog), 0 },
97 { offsetof(xfs_sb_t, sb_inodelog), 0 },
98 { offsetof(xfs_sb_t, sb_inopblog), 0 },
99 { offsetof(xfs_sb_t, sb_agblklog), 0 },
100 { offsetof(xfs_sb_t, sb_rextslog), 0 },
101 { offsetof(xfs_sb_t, sb_inprogress), 0 },
102 { offsetof(xfs_sb_t, sb_imax_pct), 0 },
103 { offsetof(xfs_sb_t, sb_icount), 0 },
104 { offsetof(xfs_sb_t, sb_ifree), 0 },
105 { offsetof(xfs_sb_t, sb_fdblocks), 0 },
106 { offsetof(xfs_sb_t, sb_frextents), 0 },
107 { offsetof(xfs_sb_t, sb_uquotino), 0 },
108 { offsetof(xfs_sb_t, sb_gquotino), 0 },
109 { offsetof(xfs_sb_t, sb_qflags), 0 },
110 { offsetof(xfs_sb_t, sb_flags), 0 },
111 { offsetof(xfs_sb_t, sb_shared_vn), 0 },
112 { offsetof(xfs_sb_t, sb_inoalignmt), 0 },
113 { offsetof(xfs_sb_t, sb_unit), 0 },
114 { offsetof(xfs_sb_t, sb_width), 0 },
115 { offsetof(xfs_sb_t, sb_dirblklog), 0 },
116 { offsetof(xfs_sb_t, sb_logsectlog), 0 },
117 { offsetof(xfs_sb_t, sb_logsectsize),0 },
118 { offsetof(xfs_sb_t, sb_logsunit), 0 },
119 { offsetof(xfs_sb_t, sb_features2), 0 },
120 { offsetof(xfs_sb_t, sb_bad_features2), 0 },
121 { sizeof(xfs_sb_t), 0 }
125 * Free up the resources associated with a mount structure. Assume that
126 * the structure was initially zeroed, so we can tell which fields got
136 for (agno = 0; agno < mp->m_maxagi; agno++)
137 if (mp->m_perag[agno].pagb_list)
138 kmem_free(mp->m_perag[agno].pagb_list);
139 kmem_free(mp->m_perag);
144 * Check size of device based on the (data/realtime) block count.
145 * Note: this check is used by the growfs code as well as mount.
148 xfs_sb_validate_fsb_count(
152 ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
153 ASSERT(sbp->sb_blocklog >= BBSHIFT);
155 #if XFS_BIG_BLKNOS /* Limited by ULONG_MAX of page cache index */
156 if (nblocks >> (PAGE_CACHE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
158 #else /* Limited by UINT_MAX of sectors */
159 if (nblocks << (sbp->sb_blocklog - BBSHIFT) > UINT_MAX)
166 * Check the validity of the SB found.
169 xfs_mount_validate_sb(
175 * If the log device and data device have the
176 * same device number, the log is internal.
177 * Consequently, the sb_logstart should be non-zero. If
178 * we have a zero sb_logstart in this case, we may be trying to mount
179 * a volume filesystem in a non-volume manner.
181 if (sbp->sb_magicnum != XFS_SB_MAGIC) {
182 xfs_fs_mount_cmn_err(flags, "bad magic number");
183 return XFS_ERROR(EWRONGFS);
186 if (!xfs_sb_good_version(sbp)) {
187 xfs_fs_mount_cmn_err(flags, "bad version");
188 return XFS_ERROR(EWRONGFS);
192 sbp->sb_logstart == 0 && mp->m_logdev_targp == mp->m_ddev_targp)) {
193 xfs_fs_mount_cmn_err(flags,
194 "filesystem is marked as having an external log; "
195 "specify logdev on the\nmount command line.");
196 return XFS_ERROR(EINVAL);
200 sbp->sb_logstart != 0 && mp->m_logdev_targp != mp->m_ddev_targp)) {
201 xfs_fs_mount_cmn_err(flags,
202 "filesystem is marked as having an internal log; "
203 "do not specify logdev on\nthe mount command line.");
204 return XFS_ERROR(EINVAL);
208 * More sanity checking. These were stolen directly from
212 sbp->sb_agcount <= 0 ||
213 sbp->sb_sectsize < XFS_MIN_SECTORSIZE ||
214 sbp->sb_sectsize > XFS_MAX_SECTORSIZE ||
215 sbp->sb_sectlog < XFS_MIN_SECTORSIZE_LOG ||
216 sbp->sb_sectlog > XFS_MAX_SECTORSIZE_LOG ||
217 sbp->sb_blocksize < XFS_MIN_BLOCKSIZE ||
218 sbp->sb_blocksize > XFS_MAX_BLOCKSIZE ||
219 sbp->sb_blocklog < XFS_MIN_BLOCKSIZE_LOG ||
220 sbp->sb_blocklog > XFS_MAX_BLOCKSIZE_LOG ||
221 sbp->sb_inodesize < XFS_DINODE_MIN_SIZE ||
222 sbp->sb_inodesize > XFS_DINODE_MAX_SIZE ||
223 sbp->sb_inodelog < XFS_DINODE_MIN_LOG ||
224 sbp->sb_inodelog > XFS_DINODE_MAX_LOG ||
225 (sbp->sb_blocklog - sbp->sb_inodelog != sbp->sb_inopblog) ||
226 (sbp->sb_rextsize * sbp->sb_blocksize > XFS_MAX_RTEXTSIZE) ||
227 (sbp->sb_rextsize * sbp->sb_blocksize < XFS_MIN_RTEXTSIZE) ||
228 (sbp->sb_imax_pct > 100 /* zero sb_imax_pct is valid */))) {
229 xfs_fs_mount_cmn_err(flags, "SB sanity check 1 failed");
230 return XFS_ERROR(EFSCORRUPTED);
234 * Sanity check AG count, size fields against data size field
237 sbp->sb_dblocks == 0 ||
239 (xfs_drfsbno_t)sbp->sb_agcount * sbp->sb_agblocks ||
240 sbp->sb_dblocks < (xfs_drfsbno_t)(sbp->sb_agcount - 1) *
241 sbp->sb_agblocks + XFS_MIN_AG_BLOCKS)) {
242 xfs_fs_mount_cmn_err(flags, "SB sanity check 2 failed");
243 return XFS_ERROR(EFSCORRUPTED);
247 * Until this is fixed only page-sized or smaller data blocks work.
249 if (unlikely(sbp->sb_blocksize > PAGE_SIZE)) {
250 xfs_fs_mount_cmn_err(flags,
251 "file system with blocksize %d bytes",
253 xfs_fs_mount_cmn_err(flags,
254 "only pagesize (%ld) or less will currently work.",
256 return XFS_ERROR(ENOSYS);
259 if (xfs_sb_validate_fsb_count(sbp, sbp->sb_dblocks) ||
260 xfs_sb_validate_fsb_count(sbp, sbp->sb_rblocks)) {
261 xfs_fs_mount_cmn_err(flags,
262 "file system too large to be mounted on this system.");
263 return XFS_ERROR(E2BIG);
266 if (unlikely(sbp->sb_inprogress)) {
267 xfs_fs_mount_cmn_err(flags, "file system busy");
268 return XFS_ERROR(EFSCORRUPTED);
272 * Version 1 directory format has never worked on Linux.
274 if (unlikely(!xfs_sb_version_hasdirv2(sbp))) {
275 xfs_fs_mount_cmn_err(flags,
276 "file system using version 1 directory format");
277 return XFS_ERROR(ENOSYS);
284 xfs_initialize_perag_icache(
287 if (!pag->pag_ici_init) {
288 rwlock_init(&pag->pag_ici_lock);
289 INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
290 pag->pag_ici_init = 1;
295 xfs_initialize_perag(
297 xfs_agnumber_t agcount)
299 xfs_agnumber_t index, max_metadata;
303 xfs_sb_t *sbp = &mp->m_sb;
304 xfs_ino_t max_inum = XFS_MAXINUMBER_32;
306 /* Check to see if the filesystem can overflow 32 bit inodes */
307 agino = XFS_OFFBNO_TO_AGINO(mp, sbp->sb_agblocks - 1, 0);
308 ino = XFS_AGINO_TO_INO(mp, agcount - 1, agino);
310 /* Clear the mount flag if no inode can overflow 32 bits
311 * on this filesystem, or if specifically requested..
313 if ((mp->m_flags & XFS_MOUNT_SMALL_INUMS) && ino > max_inum) {
314 mp->m_flags |= XFS_MOUNT_32BITINODES;
316 mp->m_flags &= ~XFS_MOUNT_32BITINODES;
319 /* If we can overflow then setup the ag headers accordingly */
320 if (mp->m_flags & XFS_MOUNT_32BITINODES) {
321 /* Calculate how much should be reserved for inodes to
322 * meet the max inode percentage.
324 if (mp->m_maxicount) {
327 icount = sbp->sb_dblocks * sbp->sb_imax_pct;
329 icount += sbp->sb_agblocks - 1;
330 do_div(icount, sbp->sb_agblocks);
331 max_metadata = icount;
333 max_metadata = agcount;
335 for (index = 0; index < agcount; index++) {
336 ino = XFS_AGINO_TO_INO(mp, index, agino);
337 if (ino > max_inum) {
342 /* This ag is preferred for inodes */
343 pag = &mp->m_perag[index];
344 pag->pagi_inodeok = 1;
345 if (index < max_metadata)
346 pag->pagf_metadata = 1;
347 xfs_initialize_perag_icache(pag);
350 /* Setup default behavior for smaller filesystems */
351 for (index = 0; index < agcount; index++) {
352 pag = &mp->m_perag[index];
353 pag->pagi_inodeok = 1;
354 xfs_initialize_perag_icache(pag);
365 to->sb_magicnum = be32_to_cpu(from->sb_magicnum);
366 to->sb_blocksize = be32_to_cpu(from->sb_blocksize);
367 to->sb_dblocks = be64_to_cpu(from->sb_dblocks);
368 to->sb_rblocks = be64_to_cpu(from->sb_rblocks);
369 to->sb_rextents = be64_to_cpu(from->sb_rextents);
370 memcpy(&to->sb_uuid, &from->sb_uuid, sizeof(to->sb_uuid));
371 to->sb_logstart = be64_to_cpu(from->sb_logstart);
372 to->sb_rootino = be64_to_cpu(from->sb_rootino);
373 to->sb_rbmino = be64_to_cpu(from->sb_rbmino);
374 to->sb_rsumino = be64_to_cpu(from->sb_rsumino);
375 to->sb_rextsize = be32_to_cpu(from->sb_rextsize);
376 to->sb_agblocks = be32_to_cpu(from->sb_agblocks);
377 to->sb_agcount = be32_to_cpu(from->sb_agcount);
378 to->sb_rbmblocks = be32_to_cpu(from->sb_rbmblocks);
379 to->sb_logblocks = be32_to_cpu(from->sb_logblocks);
380 to->sb_versionnum = be16_to_cpu(from->sb_versionnum);
381 to->sb_sectsize = be16_to_cpu(from->sb_sectsize);
382 to->sb_inodesize = be16_to_cpu(from->sb_inodesize);
383 to->sb_inopblock = be16_to_cpu(from->sb_inopblock);
384 memcpy(&to->sb_fname, &from->sb_fname, sizeof(to->sb_fname));
385 to->sb_blocklog = from->sb_blocklog;
386 to->sb_sectlog = from->sb_sectlog;
387 to->sb_inodelog = from->sb_inodelog;
388 to->sb_inopblog = from->sb_inopblog;
389 to->sb_agblklog = from->sb_agblklog;
390 to->sb_rextslog = from->sb_rextslog;
391 to->sb_inprogress = from->sb_inprogress;
392 to->sb_imax_pct = from->sb_imax_pct;
393 to->sb_icount = be64_to_cpu(from->sb_icount);
394 to->sb_ifree = be64_to_cpu(from->sb_ifree);
395 to->sb_fdblocks = be64_to_cpu(from->sb_fdblocks);
396 to->sb_frextents = be64_to_cpu(from->sb_frextents);
397 to->sb_uquotino = be64_to_cpu(from->sb_uquotino);
398 to->sb_gquotino = be64_to_cpu(from->sb_gquotino);
399 to->sb_qflags = be16_to_cpu(from->sb_qflags);
400 to->sb_flags = from->sb_flags;
401 to->sb_shared_vn = from->sb_shared_vn;
402 to->sb_inoalignmt = be32_to_cpu(from->sb_inoalignmt);
403 to->sb_unit = be32_to_cpu(from->sb_unit);
404 to->sb_width = be32_to_cpu(from->sb_width);
405 to->sb_dirblklog = from->sb_dirblklog;
406 to->sb_logsectlog = from->sb_logsectlog;
407 to->sb_logsectsize = be16_to_cpu(from->sb_logsectsize);
408 to->sb_logsunit = be32_to_cpu(from->sb_logsunit);
409 to->sb_features2 = be32_to_cpu(from->sb_features2);
410 to->sb_bad_features2 = be32_to_cpu(from->sb_bad_features2);
414 * Copy in core superblock to ondisk one.
416 * The fields argument is mask of superblock fields to copy.
424 xfs_caddr_t to_ptr = (xfs_caddr_t)to;
425 xfs_caddr_t from_ptr = (xfs_caddr_t)from;
435 f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
436 first = xfs_sb_info[f].offset;
437 size = xfs_sb_info[f + 1].offset - first;
439 ASSERT(xfs_sb_info[f].type == 0 || xfs_sb_info[f].type == 1);
441 if (size == 1 || xfs_sb_info[f].type == 1) {
442 memcpy(to_ptr + first, from_ptr + first, size);
446 *(__be16 *)(to_ptr + first) =
447 cpu_to_be16(*(__u16 *)(from_ptr + first));
450 *(__be32 *)(to_ptr + first) =
451 cpu_to_be32(*(__u32 *)(from_ptr + first));
454 *(__be64 *)(to_ptr + first) =
455 cpu_to_be64(*(__u64 *)(from_ptr + first));
462 fields &= ~(1LL << f);
469 * Does the initial read of the superblock.
472 xfs_readsb(xfs_mount_t *mp, int flags)
474 unsigned int sector_size;
475 unsigned int extra_flags;
479 ASSERT(mp->m_sb_bp == NULL);
480 ASSERT(mp->m_ddev_targp != NULL);
483 * Allocate a (locked) buffer to hold the superblock.
484 * This will be kept around at all times to optimize
485 * access to the superblock.
487 sector_size = xfs_getsize_buftarg(mp->m_ddev_targp);
488 extra_flags = XFS_BUF_LOCK | XFS_BUF_MANAGE | XFS_BUF_MAPPED;
490 bp = xfs_buf_read_flags(mp->m_ddev_targp, XFS_SB_DADDR,
491 BTOBB(sector_size), extra_flags);
492 if (!bp || XFS_BUF_ISERROR(bp)) {
493 xfs_fs_mount_cmn_err(flags, "SB read failed");
494 error = bp ? XFS_BUF_GETERROR(bp) : ENOMEM;
497 ASSERT(XFS_BUF_ISBUSY(bp));
498 ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
501 * Initialize the mount structure from the superblock.
502 * But first do some basic consistency checking.
504 xfs_sb_from_disk(&mp->m_sb, XFS_BUF_TO_SBP(bp));
506 error = xfs_mount_validate_sb(mp, &(mp->m_sb), flags);
508 xfs_fs_mount_cmn_err(flags, "SB validate failed");
513 * We must be able to do sector-sized and sector-aligned IO.
515 if (sector_size > mp->m_sb.sb_sectsize) {
516 xfs_fs_mount_cmn_err(flags,
517 "device supports only %u byte sectors (not %u)",
518 sector_size, mp->m_sb.sb_sectsize);
524 * If device sector size is smaller than the superblock size,
525 * re-read the superblock so the buffer is correctly sized.
527 if (sector_size < mp->m_sb.sb_sectsize) {
528 XFS_BUF_UNMANAGE(bp);
530 sector_size = mp->m_sb.sb_sectsize;
531 bp = xfs_buf_read_flags(mp->m_ddev_targp, XFS_SB_DADDR,
532 BTOBB(sector_size), extra_flags);
533 if (!bp || XFS_BUF_ISERROR(bp)) {
534 xfs_fs_mount_cmn_err(flags, "SB re-read failed");
535 error = bp ? XFS_BUF_GETERROR(bp) : ENOMEM;
538 ASSERT(XFS_BUF_ISBUSY(bp));
539 ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
542 /* Initialize per-cpu counters */
543 xfs_icsb_reinit_counters(mp);
547 ASSERT(XFS_BUF_VALUSEMA(bp) > 0);
552 XFS_BUF_UNMANAGE(bp);
562 * Mount initialization code establishing various mount
563 * fields from the superblock associated with the given
567 xfs_mount_common(xfs_mount_t *mp, xfs_sb_t *sbp)
569 mp->m_agfrotor = mp->m_agirotor = 0;
570 spin_lock_init(&mp->m_agirotor_lock);
571 mp->m_maxagi = mp->m_sb.sb_agcount;
572 mp->m_blkbit_log = sbp->sb_blocklog + XFS_NBBYLOG;
573 mp->m_blkbb_log = sbp->sb_blocklog - BBSHIFT;
574 mp->m_sectbb_log = sbp->sb_sectlog - BBSHIFT;
575 mp->m_agno_log = xfs_highbit32(sbp->sb_agcount - 1) + 1;
576 mp->m_agino_log = sbp->sb_inopblog + sbp->sb_agblklog;
577 mp->m_litino = sbp->sb_inodesize - sizeof(struct xfs_dinode);
578 mp->m_blockmask = sbp->sb_blocksize - 1;
579 mp->m_blockwsize = sbp->sb_blocksize >> XFS_WORDLOG;
580 mp->m_blockwmask = mp->m_blockwsize - 1;
583 * Setup for attributes, in case they get created.
584 * This value is for inodes getting attributes for the first time,
585 * the per-inode value is for old attribute values.
587 ASSERT(sbp->sb_inodesize >= 256 && sbp->sb_inodesize <= 2048);
588 switch (sbp->sb_inodesize) {
590 mp->m_attroffset = XFS_LITINO(mp) -
591 XFS_BMDR_SPACE_CALC(MINABTPTRS);
596 mp->m_attroffset = XFS_BMDR_SPACE_CALC(6 * MINABTPTRS);
601 ASSERT(mp->m_attroffset < XFS_LITINO(mp));
603 mp->m_alloc_mxr[0] = xfs_allocbt_maxrecs(mp, sbp->sb_blocksize, 1);
604 mp->m_alloc_mxr[1] = xfs_allocbt_maxrecs(mp, sbp->sb_blocksize, 0);
605 mp->m_alloc_mnr[0] = mp->m_alloc_mxr[0] / 2;
606 mp->m_alloc_mnr[1] = mp->m_alloc_mxr[1] / 2;
608 mp->m_inobt_mxr[0] = xfs_inobt_maxrecs(mp, sbp->sb_blocksize, 1);
609 mp->m_inobt_mxr[1] = xfs_inobt_maxrecs(mp, sbp->sb_blocksize, 0);
610 mp->m_inobt_mnr[0] = mp->m_inobt_mxr[0] / 2;
611 mp->m_inobt_mnr[1] = mp->m_inobt_mxr[1] / 2;
613 mp->m_bmap_dmxr[0] = xfs_bmbt_maxrecs(mp, sbp->sb_blocksize, 1);
614 mp->m_bmap_dmxr[1] = xfs_bmbt_maxrecs(mp, sbp->sb_blocksize, 0);
615 mp->m_bmap_dmnr[0] = mp->m_bmap_dmxr[0] / 2;
616 mp->m_bmap_dmnr[1] = mp->m_bmap_dmxr[1] / 2;
618 mp->m_bsize = XFS_FSB_TO_BB(mp, 1);
619 mp->m_ialloc_inos = (int)MAX((__uint16_t)XFS_INODES_PER_CHUNK,
621 mp->m_ialloc_blks = mp->m_ialloc_inos >> sbp->sb_inopblog;
625 * xfs_initialize_perag_data
627 * Read in each per-ag structure so we can count up the number of
628 * allocated inodes, free inodes and used filesystem blocks as this
629 * information is no longer persistent in the superblock. Once we have
630 * this information, write it into the in-core superblock structure.
633 xfs_initialize_perag_data(xfs_mount_t *mp, xfs_agnumber_t agcount)
635 xfs_agnumber_t index;
637 xfs_sb_t *sbp = &mp->m_sb;
641 uint64_t bfreelst = 0;
645 for (index = 0; index < agcount; index++) {
647 * read the agf, then the agi. This gets us
648 * all the inforamtion we need and populates the
649 * per-ag structures for us.
651 error = xfs_alloc_pagf_init(mp, NULL, index, 0);
655 error = xfs_ialloc_pagi_init(mp, NULL, index);
658 pag = &mp->m_perag[index];
659 ifree += pag->pagi_freecount;
660 ialloc += pag->pagi_count;
661 bfree += pag->pagf_freeblks;
662 bfreelst += pag->pagf_flcount;
663 btree += pag->pagf_btreeblks;
666 * Overwrite incore superblock counters with just-read data
668 spin_lock(&mp->m_sb_lock);
669 sbp->sb_ifree = ifree;
670 sbp->sb_icount = ialloc;
671 sbp->sb_fdblocks = bfree + bfreelst + btree;
672 spin_unlock(&mp->m_sb_lock);
674 /* Fixup the per-cpu counters as well. */
675 xfs_icsb_reinit_counters(mp);
681 * Update alignment values based on mount options and sb values
684 xfs_update_alignment(xfs_mount_t *mp)
686 xfs_sb_t *sbp = &(mp->m_sb);
690 * If stripe unit and stripe width are not multiples
691 * of the fs blocksize turn off alignment.
693 if ((BBTOB(mp->m_dalign) & mp->m_blockmask) ||
694 (BBTOB(mp->m_swidth) & mp->m_blockmask)) {
695 if (mp->m_flags & XFS_MOUNT_RETERR) {
697 "XFS: alignment check 1 failed");
698 return XFS_ERROR(EINVAL);
700 mp->m_dalign = mp->m_swidth = 0;
703 * Convert the stripe unit and width to FSBs.
705 mp->m_dalign = XFS_BB_TO_FSBT(mp, mp->m_dalign);
706 if (mp->m_dalign && (sbp->sb_agblocks % mp->m_dalign)) {
707 if (mp->m_flags & XFS_MOUNT_RETERR) {
708 return XFS_ERROR(EINVAL);
710 xfs_fs_cmn_err(CE_WARN, mp,
711 "stripe alignment turned off: sunit(%d)/swidth(%d) incompatible with agsize(%d)",
712 mp->m_dalign, mp->m_swidth,
717 } else if (mp->m_dalign) {
718 mp->m_swidth = XFS_BB_TO_FSBT(mp, mp->m_swidth);
720 if (mp->m_flags & XFS_MOUNT_RETERR) {
721 xfs_fs_cmn_err(CE_WARN, mp,
722 "stripe alignment turned off: sunit(%d) less than bsize(%d)",
725 return XFS_ERROR(EINVAL);
732 * Update superblock with new values
735 if (xfs_sb_version_hasdalign(sbp)) {
736 if (sbp->sb_unit != mp->m_dalign) {
737 sbp->sb_unit = mp->m_dalign;
738 mp->m_update_flags |= XFS_SB_UNIT;
740 if (sbp->sb_width != mp->m_swidth) {
741 sbp->sb_width = mp->m_swidth;
742 mp->m_update_flags |= XFS_SB_WIDTH;
745 } else if ((mp->m_flags & XFS_MOUNT_NOALIGN) != XFS_MOUNT_NOALIGN &&
746 xfs_sb_version_hasdalign(&mp->m_sb)) {
747 mp->m_dalign = sbp->sb_unit;
748 mp->m_swidth = sbp->sb_width;
755 * Set the maximum inode count for this filesystem
758 xfs_set_maxicount(xfs_mount_t *mp)
760 xfs_sb_t *sbp = &(mp->m_sb);
763 if (sbp->sb_imax_pct) {
765 * Make sure the maximum inode count is a multiple
766 * of the units we allocate inodes in.
768 icount = sbp->sb_dblocks * sbp->sb_imax_pct;
770 do_div(icount, mp->m_ialloc_blks);
771 mp->m_maxicount = (icount * mp->m_ialloc_blks) <<
779 * Set the default minimum read and write sizes unless
780 * already specified in a mount option.
781 * We use smaller I/O sizes when the file system
782 * is being used for NFS service (wsync mount option).
785 xfs_set_rw_sizes(xfs_mount_t *mp)
787 xfs_sb_t *sbp = &(mp->m_sb);
788 int readio_log, writeio_log;
790 if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
791 if (mp->m_flags & XFS_MOUNT_WSYNC) {
792 readio_log = XFS_WSYNC_READIO_LOG;
793 writeio_log = XFS_WSYNC_WRITEIO_LOG;
795 readio_log = XFS_READIO_LOG_LARGE;
796 writeio_log = XFS_WRITEIO_LOG_LARGE;
799 readio_log = mp->m_readio_log;
800 writeio_log = mp->m_writeio_log;
803 if (sbp->sb_blocklog > readio_log) {
804 mp->m_readio_log = sbp->sb_blocklog;
806 mp->m_readio_log = readio_log;
808 mp->m_readio_blocks = 1 << (mp->m_readio_log - sbp->sb_blocklog);
809 if (sbp->sb_blocklog > writeio_log) {
810 mp->m_writeio_log = sbp->sb_blocklog;
812 mp->m_writeio_log = writeio_log;
814 mp->m_writeio_blocks = 1 << (mp->m_writeio_log - sbp->sb_blocklog);
818 * Set whether we're using inode alignment.
821 xfs_set_inoalignment(xfs_mount_t *mp)
823 if (xfs_sb_version_hasalign(&mp->m_sb) &&
824 mp->m_sb.sb_inoalignmt >=
825 XFS_B_TO_FSBT(mp, mp->m_inode_cluster_size))
826 mp->m_inoalign_mask = mp->m_sb.sb_inoalignmt - 1;
828 mp->m_inoalign_mask = 0;
830 * If we are using stripe alignment, check whether
831 * the stripe unit is a multiple of the inode alignment
833 if (mp->m_dalign && mp->m_inoalign_mask &&
834 !(mp->m_dalign & mp->m_inoalign_mask))
835 mp->m_sinoalign = mp->m_dalign;
841 * Check that the data (and log if separate) are an ok size.
844 xfs_check_sizes(xfs_mount_t *mp)
850 d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
851 if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
852 cmn_err(CE_WARN, "XFS: size check 1 failed");
853 return XFS_ERROR(E2BIG);
855 error = xfs_read_buf(mp, mp->m_ddev_targp,
856 d - XFS_FSS_TO_BB(mp, 1),
857 XFS_FSS_TO_BB(mp, 1), 0, &bp);
861 cmn_err(CE_WARN, "XFS: size check 2 failed");
863 error = XFS_ERROR(E2BIG);
867 if (mp->m_logdev_targp != mp->m_ddev_targp) {
868 d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
869 if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
870 cmn_err(CE_WARN, "XFS: size check 3 failed");
871 return XFS_ERROR(E2BIG);
873 error = xfs_read_buf(mp, mp->m_logdev_targp,
874 d - XFS_FSB_TO_BB(mp, 1),
875 XFS_FSB_TO_BB(mp, 1), 0, &bp);
879 cmn_err(CE_WARN, "XFS: size check 3 failed");
881 error = XFS_ERROR(E2BIG);
889 * This function does the following on an initial mount of a file system:
890 * - reads the superblock from disk and init the mount struct
891 * - if we're a 32-bit kernel, do a size check on the superblock
892 * so we don't mount terabyte filesystems
893 * - init mount struct realtime fields
894 * - allocate inode hash table for fs
895 * - init directory manager
896 * - perform recovery and init the log manager
902 xfs_sb_t *sbp = &(mp->m_sb);
905 uint quotamount, quotaflags;
908 xfs_mount_common(mp, sbp);
911 * Check for a mismatched features2 values. Older kernels
912 * read & wrote into the wrong sb offset for sb_features2
913 * on some platforms due to xfs_sb_t not being 64bit size aligned
914 * when sb_features2 was added, which made older superblock
915 * reading/writing routines swap it as a 64-bit value.
917 * For backwards compatibility, we make both slots equal.
919 * If we detect a mismatched field, we OR the set bits into the
920 * existing features2 field in case it has already been modified; we
921 * don't want to lose any features. We then update the bad location
922 * with the ORed value so that older kernels will see any features2
923 * flags, and mark the two fields as needing updates once the
924 * transaction subsystem is online.
926 if (xfs_sb_has_mismatched_features2(sbp)) {
928 "XFS: correcting sb_features alignment problem");
929 sbp->sb_features2 |= sbp->sb_bad_features2;
930 sbp->sb_bad_features2 = sbp->sb_features2;
931 mp->m_update_flags |= XFS_SB_FEATURES2 | XFS_SB_BAD_FEATURES2;
934 * Re-check for ATTR2 in case it was found in bad_features2
937 if (xfs_sb_version_hasattr2(&mp->m_sb) &&
938 !(mp->m_flags & XFS_MOUNT_NOATTR2))
939 mp->m_flags |= XFS_MOUNT_ATTR2;
942 if (xfs_sb_version_hasattr2(&mp->m_sb) &&
943 (mp->m_flags & XFS_MOUNT_NOATTR2)) {
944 xfs_sb_version_removeattr2(&mp->m_sb);
945 mp->m_update_flags |= XFS_SB_FEATURES2;
947 /* update sb_versionnum for the clearing of the morebits */
948 if (!sbp->sb_features2)
949 mp->m_update_flags |= XFS_SB_VERSIONNUM;
953 * Check if sb_agblocks is aligned at stripe boundary
954 * If sb_agblocks is NOT aligned turn off m_dalign since
955 * allocator alignment is within an ag, therefore ag has
956 * to be aligned at stripe boundary.
958 error = xfs_update_alignment(mp);
962 xfs_alloc_compute_maxlevels(mp);
963 xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK);
964 xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK);
965 xfs_ialloc_compute_maxlevels(mp);
967 xfs_set_maxicount(mp);
969 mp->m_maxioffset = xfs_max_file_offset(sbp->sb_blocklog);
972 * XFS uses the uuid from the superblock as the unique
973 * identifier for fsid. We can not use the uuid from the volume
974 * since a single partition filesystem is identical to a single
975 * partition volume/filesystem.
977 if (!(mp->m_flags & XFS_MOUNT_NOUUID)) {
978 if (xfs_uuid_mount(mp)) {
979 error = XFS_ERROR(EINVAL);
985 * Set the minimum read and write sizes
987 xfs_set_rw_sizes(mp);
990 * Set the inode cluster size.
991 * This may still be overridden by the file system
992 * block size if it is larger than the chosen cluster size.
994 mp->m_inode_cluster_size = XFS_INODE_BIG_CLUSTER_SIZE;
997 * Set inode alignment fields
999 xfs_set_inoalignment(mp);
1002 * Check that the data (and log if separate) are an ok size.
1004 error = xfs_check_sizes(mp);
1006 goto out_remove_uuid;
1009 * Initialize realtime fields in the mount structure
1011 error = xfs_rtmount_init(mp);
1013 cmn_err(CE_WARN, "XFS: RT mount failed");
1014 goto out_remove_uuid;
1018 * Copies the low order bits of the timestamp and the randomly
1019 * set "sequence" number out of a UUID.
1021 uuid_getnodeuniq(&sbp->sb_uuid, mp->m_fixedfsid);
1023 mp->m_dmevmask = 0; /* not persistent; set after each mount */
1028 * Initialize the attribute manager's entries.
1030 mp->m_attr_magicpct = (mp->m_sb.sb_blocksize * 37) / 100;
1033 * Initialize the precomputed transaction reservations values.
1038 * Allocate and initialize the per-ag data.
1040 init_rwsem(&mp->m_peraglock);
1041 mp->m_perag = kmem_zalloc(sbp->sb_agcount * sizeof(xfs_perag_t),
1044 goto out_remove_uuid;
1046 mp->m_maxagi = xfs_initialize_perag(mp, sbp->sb_agcount);
1048 if (!sbp->sb_logblocks) {
1049 cmn_err(CE_WARN, "XFS: no log defined");
1050 XFS_ERROR_REPORT("xfs_mountfs", XFS_ERRLEVEL_LOW, mp);
1051 error = XFS_ERROR(EFSCORRUPTED);
1052 goto out_free_perag;
1056 * log's mount-time initialization. Perform 1st part recovery if needed
1058 error = xfs_log_mount(mp, mp->m_logdev_targp,
1059 XFS_FSB_TO_DADDR(mp, sbp->sb_logstart),
1060 XFS_FSB_TO_BB(mp, sbp->sb_logblocks));
1062 cmn_err(CE_WARN, "XFS: log mount failed");
1063 goto out_free_perag;
1067 * Now the log is mounted, we know if it was an unclean shutdown or
1068 * not. If it was, with the first phase of recovery has completed, we
1069 * have consistent AG blocks on disk. We have not recovered EFIs yet,
1070 * but they are recovered transactionally in the second recovery phase
1073 * Hence we can safely re-initialise incore superblock counters from
1074 * the per-ag data. These may not be correct if the filesystem was not
1075 * cleanly unmounted, so we need to wait for recovery to finish before
1078 * If the filesystem was cleanly unmounted, then we can trust the
1079 * values in the superblock to be correct and we don't need to do
1082 * If we are currently making the filesystem, the initialisation will
1083 * fail as the perag data is in an undefined state.
1085 if (xfs_sb_version_haslazysbcount(&mp->m_sb) &&
1086 !XFS_LAST_UNMOUNT_WAS_CLEAN(mp) &&
1087 !mp->m_sb.sb_inprogress) {
1088 error = xfs_initialize_perag_data(mp, sbp->sb_agcount);
1090 goto out_free_perag;
1094 * Get and sanity-check the root inode.
1095 * Save the pointer to it in the mount structure.
1097 error = xfs_iget(mp, NULL, sbp->sb_rootino, 0, XFS_ILOCK_EXCL, &rip, 0);
1099 cmn_err(CE_WARN, "XFS: failed to read root inode");
1100 goto out_log_dealloc;
1103 ASSERT(rip != NULL);
1105 if (unlikely((rip->i_d.di_mode & S_IFMT) != S_IFDIR)) {
1106 cmn_err(CE_WARN, "XFS: corrupted root inode");
1107 cmn_err(CE_WARN, "Device %s - root %llu is not a directory",
1108 XFS_BUFTARG_NAME(mp->m_ddev_targp),
1109 (unsigned long long)rip->i_ino);
1110 xfs_iunlock(rip, XFS_ILOCK_EXCL);
1111 XFS_ERROR_REPORT("xfs_mountfs_int(2)", XFS_ERRLEVEL_LOW,
1113 error = XFS_ERROR(EFSCORRUPTED);
1116 mp->m_rootip = rip; /* save it */
1118 xfs_iunlock(rip, XFS_ILOCK_EXCL);
1121 * Initialize realtime inode pointers in the mount structure
1123 error = xfs_rtmount_inodes(mp);
1126 * Free up the root inode.
1128 cmn_err(CE_WARN, "XFS: failed to read RT inodes");
1133 * If this is a read-only mount defer the superblock updates until
1134 * the next remount into writeable mode. Otherwise we would never
1135 * perform the update e.g. for the root filesystem.
1137 if (mp->m_update_flags && !(mp->m_flags & XFS_MOUNT_RDONLY)) {
1138 error = xfs_mount_log_sb(mp, mp->m_update_flags);
1140 cmn_err(CE_WARN, "XFS: failed to write sb changes");
1146 * Initialise the XFS quota management subsystem for this mount
1148 error = XFS_QM_INIT(mp, "amount, "aflags);
1153 * Finish recovering the file system. This part needed to be
1154 * delayed until after the root and real-time bitmap inodes
1155 * were consistently read in.
1157 error = xfs_log_mount_finish(mp);
1159 cmn_err(CE_WARN, "XFS: log mount finish failed");
1164 * Complete the quota initialisation, post-log-replay component.
1166 error = XFS_QM_MOUNT(mp, quotamount, quotaflags);
1171 * Now we are mounted, reserve a small amount of unused space for
1172 * privileged transactions. This is needed so that transaction
1173 * space required for critical operations can dip into this pool
1174 * when at ENOSPC. This is needed for operations like create with
1175 * attr, unwritten extent conversion at ENOSPC, etc. Data allocations
1176 * are not allowed to use this reserved space.
1178 * We default to 5% or 1024 fsbs of space reserved, whichever is smaller.
1179 * This may drive us straight to ENOSPC on mount, but that implies
1180 * we were already there on the last unmount. Warn if this occurs.
1182 resblks = mp->m_sb.sb_dblocks;
1183 do_div(resblks, 20);
1184 resblks = min_t(__uint64_t, resblks, 1024);
1185 error = xfs_reserve_blocks(mp, &resblks, NULL);
1187 cmn_err(CE_WARN, "XFS: Unable to allocate reserve blocks. "
1188 "Continuing without a reserve pool.");
1195 xfs_log_unmount_dealloc(mp);
1199 if (!(mp->m_flags & XFS_MOUNT_NOUUID))
1200 uuid_table_remove(&mp->m_sb.sb_uuid);
1206 * This flushes out the inodes,dquots and the superblock, unmounts the
1207 * log and makes sure that incore structures are freed.
1211 struct xfs_mount *mp)
1217 * Release dquot that rootinode, rbmino and rsumino might be holding,
1218 * and release the quota inodes.
1225 IRELE(mp->m_rsumip);
1226 IRELE(mp->m_rootip);
1229 * We can potentially deadlock here if we have an inode cluster
1230 * that has been freed has it's buffer still pinned in memory because
1231 * the transaction is still sitting in a iclog. The stale inodes
1232 * on that buffer will have their flush locks held until the
1233 * transaction hits the disk and the callbacks run. the inode
1234 * flush takes the flush lock unconditionally and with nothing to
1235 * push out the iclog we will never get that unlocked. hence we
1236 * need to force the log first.
1238 xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE | XFS_LOG_SYNC);
1239 xfs_reclaim_inodes(mp, 0, XFS_IFLUSH_ASYNC);
1241 XFS_QM_DQPURGEALL(mp, XFS_QMOPT_QUOTALL | XFS_QMOPT_UMOUNTING);
1243 if (mp->m_quotainfo)
1247 * Flush out the log synchronously so that we know for sure
1248 * that nothing is pinned. This is important because bflush()
1249 * will skip pinned buffers.
1251 xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE | XFS_LOG_SYNC);
1253 xfs_binval(mp->m_ddev_targp);
1254 if (mp->m_rtdev_targp) {
1255 xfs_binval(mp->m_rtdev_targp);
1259 * Unreserve any blocks we have so that when we unmount we don't account
1260 * the reserved free space as used. This is really only necessary for
1261 * lazy superblock counting because it trusts the incore superblock
1262 * counters to be aboslutely correct on clean unmount.
1264 * We don't bother correcting this elsewhere for lazy superblock
1265 * counting because on mount of an unclean filesystem we reconstruct the
1266 * correct counter value and this is irrelevant.
1268 * For non-lazy counter filesystems, this doesn't matter at all because
1269 * we only every apply deltas to the superblock and hence the incore
1270 * value does not matter....
1273 error = xfs_reserve_blocks(mp, &resblks, NULL);
1275 cmn_err(CE_WARN, "XFS: Unable to free reserved block pool. "
1276 "Freespace may not be correct on next mount.");
1278 error = xfs_log_sbcount(mp, 1);
1280 cmn_err(CE_WARN, "XFS: Unable to update superblock counters. "
1281 "Freespace may not be correct on next mount.");
1282 xfs_unmountfs_writesb(mp);
1283 xfs_unmountfs_wait(mp); /* wait for async bufs */
1284 xfs_log_unmount(mp); /* Done! No more fs ops. */
1286 if ((mp->m_flags & XFS_MOUNT_NOUUID) == 0)
1287 uuid_table_remove(&mp->m_sb.sb_uuid);
1290 xfs_errortag_clearall(mp, 0);
1296 xfs_unmountfs_wait(xfs_mount_t *mp)
1298 if (mp->m_logdev_targp != mp->m_ddev_targp)
1299 xfs_wait_buftarg(mp->m_logdev_targp);
1300 if (mp->m_rtdev_targp)
1301 xfs_wait_buftarg(mp->m_rtdev_targp);
1302 xfs_wait_buftarg(mp->m_ddev_targp);
1306 xfs_fs_writable(xfs_mount_t *mp)
1308 return !(xfs_test_for_freeze(mp) || XFS_FORCED_SHUTDOWN(mp) ||
1309 (mp->m_flags & XFS_MOUNT_RDONLY));
1315 * Called either periodically to keep the on disk superblock values
1316 * roughly up to date or from unmount to make sure the values are
1317 * correct on a clean unmount.
1319 * Note this code can be called during the process of freezing, so
1320 * we may need to use the transaction allocator which does not not
1321 * block when the transaction subsystem is in its frozen state.
1331 if (!xfs_fs_writable(mp))
1334 xfs_icsb_sync_counters(mp, 0);
1337 * we don't need to do this if we are updating the superblock
1338 * counters on every modification.
1340 if (!xfs_sb_version_haslazysbcount(&mp->m_sb))
1343 tp = _xfs_trans_alloc(mp, XFS_TRANS_SB_COUNT);
1344 error = xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0,
1345 XFS_DEFAULT_LOG_COUNT);
1347 xfs_trans_cancel(tp, 0);
1351 xfs_mod_sb(tp, XFS_SB_IFREE | XFS_SB_ICOUNT | XFS_SB_FDBLOCKS);
1353 xfs_trans_set_sync(tp);
1354 error = xfs_trans_commit(tp, 0);
1359 xfs_unmountfs_writesb(xfs_mount_t *mp)
1365 * skip superblock write if fs is read-only, or
1366 * if we are doing a forced umount.
1368 if (!((mp->m_flags & XFS_MOUNT_RDONLY) ||
1369 XFS_FORCED_SHUTDOWN(mp))) {
1371 sbp = xfs_getsb(mp, 0);
1373 XFS_BUF_UNDONE(sbp);
1374 XFS_BUF_UNREAD(sbp);
1375 XFS_BUF_UNDELAYWRITE(sbp);
1377 XFS_BUF_UNASYNC(sbp);
1378 ASSERT(XFS_BUF_TARGET(sbp) == mp->m_ddev_targp);
1379 xfsbdstrat(mp, sbp);
1380 error = xfs_iowait(sbp);
1382 xfs_ioerror_alert("xfs_unmountfs_writesb",
1383 mp, sbp, XFS_BUF_ADDR(sbp));
1390 * xfs_mod_sb() can be used to copy arbitrary changes to the
1391 * in-core superblock into the superblock buffer to be logged.
1392 * It does not provide the higher level of locking that is
1393 * needed to protect the in-core superblock from concurrent
1397 xfs_mod_sb(xfs_trans_t *tp, __int64_t fields)
1409 bp = xfs_trans_getsb(tp, mp, 0);
1410 first = sizeof(xfs_sb_t);
1413 /* translate/copy */
1415 xfs_sb_to_disk(XFS_BUF_TO_SBP(bp), &mp->m_sb, fields);
1417 /* find modified range */
1419 f = (xfs_sb_field_t)xfs_lowbit64((__uint64_t)fields);
1420 ASSERT((1LL << f) & XFS_SB_MOD_BITS);
1421 first = xfs_sb_info[f].offset;
1423 f = (xfs_sb_field_t)xfs_highbit64((__uint64_t)fields);
1424 ASSERT((1LL << f) & XFS_SB_MOD_BITS);
1425 last = xfs_sb_info[f + 1].offset - 1;
1427 xfs_trans_log_buf(tp, bp, first, last);
1432 * xfs_mod_incore_sb_unlocked() is a utility routine common used to apply
1433 * a delta to a specified field in the in-core superblock. Simply
1434 * switch on the field indicated and apply the delta to that field.
1435 * Fields are not allowed to dip below zero, so if the delta would
1436 * do this do not apply it and return EINVAL.
1438 * The m_sb_lock must be held when this routine is called.
1441 xfs_mod_incore_sb_unlocked(
1443 xfs_sb_field_t field,
1447 int scounter; /* short counter for 32 bit fields */
1448 long long lcounter; /* long counter for 64 bit fields */
1449 long long res_used, rem;
1452 * With the in-core superblock spin lock held, switch
1453 * on the indicated field. Apply the delta to the
1454 * proper field. If the fields value would dip below
1455 * 0, then do not apply the delta and return EINVAL.
1458 case XFS_SBS_ICOUNT:
1459 lcounter = (long long)mp->m_sb.sb_icount;
1463 return XFS_ERROR(EINVAL);
1465 mp->m_sb.sb_icount = lcounter;
1468 lcounter = (long long)mp->m_sb.sb_ifree;
1472 return XFS_ERROR(EINVAL);
1474 mp->m_sb.sb_ifree = lcounter;
1476 case XFS_SBS_FDBLOCKS:
1477 lcounter = (long long)
1478 mp->m_sb.sb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
1479 res_used = (long long)(mp->m_resblks - mp->m_resblks_avail);
1481 if (delta > 0) { /* Putting blocks back */
1482 if (res_used > delta) {
1483 mp->m_resblks_avail += delta;
1485 rem = delta - res_used;
1486 mp->m_resblks_avail = mp->m_resblks;
1489 } else { /* Taking blocks away */
1494 * If were out of blocks, use any available reserved blocks if
1500 lcounter = (long long)mp->m_resblks_avail + delta;
1502 return XFS_ERROR(ENOSPC);
1504 mp->m_resblks_avail = lcounter;
1506 } else { /* not reserved */
1507 return XFS_ERROR(ENOSPC);
1512 mp->m_sb.sb_fdblocks = lcounter + XFS_ALLOC_SET_ASIDE(mp);
1514 case XFS_SBS_FREXTENTS:
1515 lcounter = (long long)mp->m_sb.sb_frextents;
1518 return XFS_ERROR(ENOSPC);
1520 mp->m_sb.sb_frextents = lcounter;
1522 case XFS_SBS_DBLOCKS:
1523 lcounter = (long long)mp->m_sb.sb_dblocks;
1527 return XFS_ERROR(EINVAL);
1529 mp->m_sb.sb_dblocks = lcounter;
1531 case XFS_SBS_AGCOUNT:
1532 scounter = mp->m_sb.sb_agcount;
1536 return XFS_ERROR(EINVAL);
1538 mp->m_sb.sb_agcount = scounter;
1540 case XFS_SBS_IMAX_PCT:
1541 scounter = mp->m_sb.sb_imax_pct;
1545 return XFS_ERROR(EINVAL);
1547 mp->m_sb.sb_imax_pct = scounter;
1549 case XFS_SBS_REXTSIZE:
1550 scounter = mp->m_sb.sb_rextsize;
1554 return XFS_ERROR(EINVAL);
1556 mp->m_sb.sb_rextsize = scounter;
1558 case XFS_SBS_RBMBLOCKS:
1559 scounter = mp->m_sb.sb_rbmblocks;
1563 return XFS_ERROR(EINVAL);
1565 mp->m_sb.sb_rbmblocks = scounter;
1567 case XFS_SBS_RBLOCKS:
1568 lcounter = (long long)mp->m_sb.sb_rblocks;
1572 return XFS_ERROR(EINVAL);
1574 mp->m_sb.sb_rblocks = lcounter;
1576 case XFS_SBS_REXTENTS:
1577 lcounter = (long long)mp->m_sb.sb_rextents;
1581 return XFS_ERROR(EINVAL);
1583 mp->m_sb.sb_rextents = lcounter;
1585 case XFS_SBS_REXTSLOG:
1586 scounter = mp->m_sb.sb_rextslog;
1590 return XFS_ERROR(EINVAL);
1592 mp->m_sb.sb_rextslog = scounter;
1596 return XFS_ERROR(EINVAL);
1601 * xfs_mod_incore_sb() is used to change a field in the in-core
1602 * superblock structure by the specified delta. This modification
1603 * is protected by the m_sb_lock. Just use the xfs_mod_incore_sb_unlocked()
1604 * routine to do the work.
1609 xfs_sb_field_t field,
1615 /* check for per-cpu counters */
1617 #ifdef HAVE_PERCPU_SB
1618 case XFS_SBS_ICOUNT:
1620 case XFS_SBS_FDBLOCKS:
1621 if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1622 status = xfs_icsb_modify_counters(mp, field,
1629 spin_lock(&mp->m_sb_lock);
1630 status = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
1631 spin_unlock(&mp->m_sb_lock);
1639 * xfs_mod_incore_sb_batch() is used to change more than one field
1640 * in the in-core superblock structure at a time. This modification
1641 * is protected by a lock internal to this module. The fields and
1642 * changes to those fields are specified in the array of xfs_mod_sb
1643 * structures passed in.
1645 * Either all of the specified deltas will be applied or none of
1646 * them will. If any modified field dips below 0, then all modifications
1647 * will be backed out and EINVAL will be returned.
1650 xfs_mod_incore_sb_batch(xfs_mount_t *mp, xfs_mod_sb_t *msb, uint nmsb, int rsvd)
1656 * Loop through the array of mod structures and apply each
1657 * individually. If any fail, then back out all those
1658 * which have already been applied. Do all of this within
1659 * the scope of the m_sb_lock so that all of the changes will
1662 spin_lock(&mp->m_sb_lock);
1664 for (msbp = &msbp[0]; msbp < (msb + nmsb); msbp++) {
1666 * Apply the delta at index n. If it fails, break
1667 * from the loop so we'll fall into the undo loop
1670 switch (msbp->msb_field) {
1671 #ifdef HAVE_PERCPU_SB
1672 case XFS_SBS_ICOUNT:
1674 case XFS_SBS_FDBLOCKS:
1675 if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1676 spin_unlock(&mp->m_sb_lock);
1677 status = xfs_icsb_modify_counters(mp,
1679 msbp->msb_delta, rsvd);
1680 spin_lock(&mp->m_sb_lock);
1686 status = xfs_mod_incore_sb_unlocked(mp,
1688 msbp->msb_delta, rsvd);
1698 * If we didn't complete the loop above, then back out
1699 * any changes made to the superblock. If you add code
1700 * between the loop above and here, make sure that you
1701 * preserve the value of status. Loop back until
1702 * we step below the beginning of the array. Make sure
1703 * we don't touch anything back there.
1707 while (msbp >= msb) {
1708 switch (msbp->msb_field) {
1709 #ifdef HAVE_PERCPU_SB
1710 case XFS_SBS_ICOUNT:
1712 case XFS_SBS_FDBLOCKS:
1713 if (!(mp->m_flags & XFS_MOUNT_NO_PERCPU_SB)) {
1714 spin_unlock(&mp->m_sb_lock);
1715 status = xfs_icsb_modify_counters(mp,
1719 spin_lock(&mp->m_sb_lock);
1725 status = xfs_mod_incore_sb_unlocked(mp,
1731 ASSERT(status == 0);
1735 spin_unlock(&mp->m_sb_lock);
1740 * xfs_getsb() is called to obtain the buffer for the superblock.
1741 * The buffer is returned locked and read in from disk.
1742 * The buffer should be released with a call to xfs_brelse().
1744 * If the flags parameter is BUF_TRYLOCK, then we'll only return
1745 * the superblock buffer if it can be locked without sleeping.
1746 * If it can't then we'll return NULL.
1755 ASSERT(mp->m_sb_bp != NULL);
1757 if (flags & XFS_BUF_TRYLOCK) {
1758 if (!XFS_BUF_CPSEMA(bp)) {
1762 XFS_BUF_PSEMA(bp, PRIBIO);
1765 ASSERT(XFS_BUF_ISDONE(bp));
1770 * Used to free the superblock along various error paths.
1779 * Use xfs_getsb() so that the buffer will be locked
1780 * when we call xfs_buf_relse().
1782 bp = xfs_getsb(mp, 0);
1783 XFS_BUF_UNMANAGE(bp);
1789 * See if the UUID is unique among mounted XFS filesystems.
1790 * Mount fails if UUID is nil or a FS with the same UUID is already mounted.
1796 if (uuid_is_nil(&mp->m_sb.sb_uuid)) {
1798 "XFS: Filesystem %s has nil UUID - can't mount",
1802 if (!uuid_table_insert(&mp->m_sb.sb_uuid)) {
1804 "XFS: Filesystem %s has duplicate UUID - can't mount",
1812 * Used to log changes to the superblock unit and width fields which could
1813 * be altered by the mount options, as well as any potential sb_features2
1814 * fixup. Only the first superblock is updated.
1824 ASSERT(fields & (XFS_SB_UNIT | XFS_SB_WIDTH | XFS_SB_UUID |
1825 XFS_SB_FEATURES2 | XFS_SB_BAD_FEATURES2 |
1826 XFS_SB_VERSIONNUM));
1828 tp = xfs_trans_alloc(mp, XFS_TRANS_SB_UNIT);
1829 error = xfs_trans_reserve(tp, 0, mp->m_sb.sb_sectsize + 128, 0, 0,
1830 XFS_DEFAULT_LOG_COUNT);
1832 xfs_trans_cancel(tp, 0);
1835 xfs_mod_sb(tp, fields);
1836 error = xfs_trans_commit(tp, 0);
1841 #ifdef HAVE_PERCPU_SB
1843 * Per-cpu incore superblock counters
1845 * Simple concept, difficult implementation
1847 * Basically, replace the incore superblock counters with a distributed per cpu
1848 * counter for contended fields (e.g. free block count).
1850 * Difficulties arise in that the incore sb is used for ENOSPC checking, and
1851 * hence needs to be accurately read when we are running low on space. Hence
1852 * there is a method to enable and disable the per-cpu counters based on how
1853 * much "stuff" is available in them.
1855 * Basically, a counter is enabled if there is enough free resource to justify
1856 * running a per-cpu fast-path. If the per-cpu counter runs out (i.e. a local
1857 * ENOSPC), then we disable the counters to synchronise all callers and
1858 * re-distribute the available resources.
1860 * If, once we redistributed the available resources, we still get a failure,
1861 * we disable the per-cpu counter and go through the slow path.
1863 * The slow path is the current xfs_mod_incore_sb() function. This means that
1864 * when we disable a per-cpu counter, we need to drain it's resources back to
1865 * the global superblock. We do this after disabling the counter to prevent
1866 * more threads from queueing up on the counter.
1868 * Essentially, this means that we still need a lock in the fast path to enable
1869 * synchronisation between the global counters and the per-cpu counters. This
1870 * is not a problem because the lock will be local to a CPU almost all the time
1871 * and have little contention except when we get to ENOSPC conditions.
1873 * Basically, this lock becomes a barrier that enables us to lock out the fast
1874 * path while we do things like enabling and disabling counters and
1875 * synchronising the counters.
1879 * 1. m_sb_lock before picking up per-cpu locks
1880 * 2. per-cpu locks always picked up via for_each_online_cpu() order
1881 * 3. accurate counter sync requires m_sb_lock + per cpu locks
1882 * 4. modifying per-cpu counters requires holding per-cpu lock
1883 * 5. modifying global counters requires holding m_sb_lock
1884 * 6. enabling or disabling a counter requires holding the m_sb_lock
1885 * and _none_ of the per-cpu locks.
1887 * Disabled counters are only ever re-enabled by a balance operation
1888 * that results in more free resources per CPU than a given threshold.
1889 * To ensure counters don't remain disabled, they are rebalanced when
1890 * the global resource goes above a higher threshold (i.e. some hysteresis
1891 * is present to prevent thrashing).
1894 #ifdef CONFIG_HOTPLUG_CPU
1896 * hot-plug CPU notifier support.
1898 * We need a notifier per filesystem as we need to be able to identify
1899 * the filesystem to balance the counters out. This is achieved by
1900 * having a notifier block embedded in the xfs_mount_t and doing pointer
1901 * magic to get the mount pointer from the notifier block address.
1904 xfs_icsb_cpu_notify(
1905 struct notifier_block *nfb,
1906 unsigned long action,
1909 xfs_icsb_cnts_t *cntp;
1912 mp = (xfs_mount_t *)container_of(nfb, xfs_mount_t, m_icsb_notifier);
1913 cntp = (xfs_icsb_cnts_t *)
1914 per_cpu_ptr(mp->m_sb_cnts, (unsigned long)hcpu);
1916 case CPU_UP_PREPARE:
1917 case CPU_UP_PREPARE_FROZEN:
1918 /* Easy Case - initialize the area and locks, and
1919 * then rebalance when online does everything else for us. */
1920 memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
1923 case CPU_ONLINE_FROZEN:
1925 xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0);
1926 xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0);
1927 xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0);
1928 xfs_icsb_unlock(mp);
1931 case CPU_DEAD_FROZEN:
1932 /* Disable all the counters, then fold the dead cpu's
1933 * count into the total on the global superblock and
1934 * re-enable the counters. */
1936 spin_lock(&mp->m_sb_lock);
1937 xfs_icsb_disable_counter(mp, XFS_SBS_ICOUNT);
1938 xfs_icsb_disable_counter(mp, XFS_SBS_IFREE);
1939 xfs_icsb_disable_counter(mp, XFS_SBS_FDBLOCKS);
1941 mp->m_sb.sb_icount += cntp->icsb_icount;
1942 mp->m_sb.sb_ifree += cntp->icsb_ifree;
1943 mp->m_sb.sb_fdblocks += cntp->icsb_fdblocks;
1945 memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
1947 xfs_icsb_balance_counter_locked(mp, XFS_SBS_ICOUNT, 0);
1948 xfs_icsb_balance_counter_locked(mp, XFS_SBS_IFREE, 0);
1949 xfs_icsb_balance_counter_locked(mp, XFS_SBS_FDBLOCKS, 0);
1950 spin_unlock(&mp->m_sb_lock);
1951 xfs_icsb_unlock(mp);
1957 #endif /* CONFIG_HOTPLUG_CPU */
1960 xfs_icsb_init_counters(
1963 xfs_icsb_cnts_t *cntp;
1966 mp->m_sb_cnts = alloc_percpu(xfs_icsb_cnts_t);
1967 if (mp->m_sb_cnts == NULL)
1970 #ifdef CONFIG_HOTPLUG_CPU
1971 mp->m_icsb_notifier.notifier_call = xfs_icsb_cpu_notify;
1972 mp->m_icsb_notifier.priority = 0;
1973 register_hotcpu_notifier(&mp->m_icsb_notifier);
1974 #endif /* CONFIG_HOTPLUG_CPU */
1976 for_each_online_cpu(i) {
1977 cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
1978 memset(cntp, 0, sizeof(xfs_icsb_cnts_t));
1981 mutex_init(&mp->m_icsb_mutex);
1984 * start with all counters disabled so that the
1985 * initial balance kicks us off correctly
1987 mp->m_icsb_counters = -1;
1992 xfs_icsb_reinit_counters(
1997 * start with all counters disabled so that the
1998 * initial balance kicks us off correctly
2000 mp->m_icsb_counters = -1;
2001 xfs_icsb_balance_counter(mp, XFS_SBS_ICOUNT, 0);
2002 xfs_icsb_balance_counter(mp, XFS_SBS_IFREE, 0);
2003 xfs_icsb_balance_counter(mp, XFS_SBS_FDBLOCKS, 0);
2004 xfs_icsb_unlock(mp);
2008 xfs_icsb_destroy_counters(
2011 if (mp->m_sb_cnts) {
2012 unregister_hotcpu_notifier(&mp->m_icsb_notifier);
2013 free_percpu(mp->m_sb_cnts);
2015 mutex_destroy(&mp->m_icsb_mutex);
2020 xfs_icsb_cnts_t *icsbp)
2022 while (test_and_set_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags)) {
2028 xfs_icsb_unlock_cntr(
2029 xfs_icsb_cnts_t *icsbp)
2031 clear_bit(XFS_ICSB_FLAG_LOCK, &icsbp->icsb_flags);
2036 xfs_icsb_lock_all_counters(
2039 xfs_icsb_cnts_t *cntp;
2042 for_each_online_cpu(i) {
2043 cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
2044 xfs_icsb_lock_cntr(cntp);
2049 xfs_icsb_unlock_all_counters(
2052 xfs_icsb_cnts_t *cntp;
2055 for_each_online_cpu(i) {
2056 cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
2057 xfs_icsb_unlock_cntr(cntp);
2064 xfs_icsb_cnts_t *cnt,
2067 xfs_icsb_cnts_t *cntp;
2070 memset(cnt, 0, sizeof(xfs_icsb_cnts_t));
2072 if (!(flags & XFS_ICSB_LAZY_COUNT))
2073 xfs_icsb_lock_all_counters(mp);
2075 for_each_online_cpu(i) {
2076 cntp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, i);
2077 cnt->icsb_icount += cntp->icsb_icount;
2078 cnt->icsb_ifree += cntp->icsb_ifree;
2079 cnt->icsb_fdblocks += cntp->icsb_fdblocks;
2082 if (!(flags & XFS_ICSB_LAZY_COUNT))
2083 xfs_icsb_unlock_all_counters(mp);
2087 xfs_icsb_counter_disabled(
2089 xfs_sb_field_t field)
2091 ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
2092 return test_bit(field, &mp->m_icsb_counters);
2096 xfs_icsb_disable_counter(
2098 xfs_sb_field_t field)
2100 xfs_icsb_cnts_t cnt;
2102 ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
2105 * If we are already disabled, then there is nothing to do
2106 * here. We check before locking all the counters to avoid
2107 * the expensive lock operation when being called in the
2108 * slow path and the counter is already disabled. This is
2109 * safe because the only time we set or clear this state is under
2112 if (xfs_icsb_counter_disabled(mp, field))
2115 xfs_icsb_lock_all_counters(mp);
2116 if (!test_and_set_bit(field, &mp->m_icsb_counters)) {
2117 /* drain back to superblock */
2119 xfs_icsb_count(mp, &cnt, XFS_ICSB_LAZY_COUNT);
2121 case XFS_SBS_ICOUNT:
2122 mp->m_sb.sb_icount = cnt.icsb_icount;
2125 mp->m_sb.sb_ifree = cnt.icsb_ifree;
2127 case XFS_SBS_FDBLOCKS:
2128 mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
2135 xfs_icsb_unlock_all_counters(mp);
2139 xfs_icsb_enable_counter(
2141 xfs_sb_field_t field,
2145 xfs_icsb_cnts_t *cntp;
2148 ASSERT((field >= XFS_SBS_ICOUNT) && (field <= XFS_SBS_FDBLOCKS));
2150 xfs_icsb_lock_all_counters(mp);
2151 for_each_online_cpu(i) {
2152 cntp = per_cpu_ptr(mp->m_sb_cnts, i);
2154 case XFS_SBS_ICOUNT:
2155 cntp->icsb_icount = count + resid;
2158 cntp->icsb_ifree = count + resid;
2160 case XFS_SBS_FDBLOCKS:
2161 cntp->icsb_fdblocks = count + resid;
2169 clear_bit(field, &mp->m_icsb_counters);
2170 xfs_icsb_unlock_all_counters(mp);
2174 xfs_icsb_sync_counters_locked(
2178 xfs_icsb_cnts_t cnt;
2180 xfs_icsb_count(mp, &cnt, flags);
2182 if (!xfs_icsb_counter_disabled(mp, XFS_SBS_ICOUNT))
2183 mp->m_sb.sb_icount = cnt.icsb_icount;
2184 if (!xfs_icsb_counter_disabled(mp, XFS_SBS_IFREE))
2185 mp->m_sb.sb_ifree = cnt.icsb_ifree;
2186 if (!xfs_icsb_counter_disabled(mp, XFS_SBS_FDBLOCKS))
2187 mp->m_sb.sb_fdblocks = cnt.icsb_fdblocks;
2191 * Accurate update of per-cpu counters to incore superblock
2194 xfs_icsb_sync_counters(
2198 spin_lock(&mp->m_sb_lock);
2199 xfs_icsb_sync_counters_locked(mp, flags);
2200 spin_unlock(&mp->m_sb_lock);
2204 * Balance and enable/disable counters as necessary.
2206 * Thresholds for re-enabling counters are somewhat magic. inode counts are
2207 * chosen to be the same number as single on disk allocation chunk per CPU, and
2208 * free blocks is something far enough zero that we aren't going thrash when we
2209 * get near ENOSPC. We also need to supply a minimum we require per cpu to
2210 * prevent looping endlessly when xfs_alloc_space asks for more than will
2211 * be distributed to a single CPU but each CPU has enough blocks to be
2214 * Note that we can be called when counters are already disabled.
2215 * xfs_icsb_disable_counter() optimises the counter locking in this case to
2216 * prevent locking every per-cpu counter needlessly.
2219 #define XFS_ICSB_INO_CNTR_REENABLE (uint64_t)64
2220 #define XFS_ICSB_FDBLK_CNTR_REENABLE(mp) \
2221 (uint64_t)(512 + XFS_ALLOC_SET_ASIDE(mp))
2223 xfs_icsb_balance_counter_locked(
2225 xfs_sb_field_t field,
2228 uint64_t count, resid;
2229 int weight = num_online_cpus();
2230 uint64_t min = (uint64_t)min_per_cpu;
2232 /* disable counter and sync counter */
2233 xfs_icsb_disable_counter(mp, field);
2235 /* update counters - first CPU gets residual*/
2237 case XFS_SBS_ICOUNT:
2238 count = mp->m_sb.sb_icount;
2239 resid = do_div(count, weight);
2240 if (count < max(min, XFS_ICSB_INO_CNTR_REENABLE))
2244 count = mp->m_sb.sb_ifree;
2245 resid = do_div(count, weight);
2246 if (count < max(min, XFS_ICSB_INO_CNTR_REENABLE))
2249 case XFS_SBS_FDBLOCKS:
2250 count = mp->m_sb.sb_fdblocks;
2251 resid = do_div(count, weight);
2252 if (count < max(min, XFS_ICSB_FDBLK_CNTR_REENABLE(mp)))
2257 count = resid = 0; /* quiet, gcc */
2261 xfs_icsb_enable_counter(mp, field, count, resid);
2265 xfs_icsb_balance_counter(
2267 xfs_sb_field_t fields,
2270 spin_lock(&mp->m_sb_lock);
2271 xfs_icsb_balance_counter_locked(mp, fields, min_per_cpu);
2272 spin_unlock(&mp->m_sb_lock);
2276 xfs_icsb_modify_counters(
2278 xfs_sb_field_t field,
2282 xfs_icsb_cnts_t *icsbp;
2283 long long lcounter; /* long counter for 64 bit fields */
2289 icsbp = (xfs_icsb_cnts_t *)per_cpu_ptr(mp->m_sb_cnts, cpu);
2292 * if the counter is disabled, go to slow path
2294 if (unlikely(xfs_icsb_counter_disabled(mp, field)))
2296 xfs_icsb_lock_cntr(icsbp);
2297 if (unlikely(xfs_icsb_counter_disabled(mp, field))) {
2298 xfs_icsb_unlock_cntr(icsbp);
2303 case XFS_SBS_ICOUNT:
2304 lcounter = icsbp->icsb_icount;
2306 if (unlikely(lcounter < 0))
2307 goto balance_counter;
2308 icsbp->icsb_icount = lcounter;
2312 lcounter = icsbp->icsb_ifree;
2314 if (unlikely(lcounter < 0))
2315 goto balance_counter;
2316 icsbp->icsb_ifree = lcounter;
2319 case XFS_SBS_FDBLOCKS:
2320 BUG_ON((mp->m_resblks - mp->m_resblks_avail) != 0);
2322 lcounter = icsbp->icsb_fdblocks - XFS_ALLOC_SET_ASIDE(mp);
2324 if (unlikely(lcounter < 0))
2325 goto balance_counter;
2326 icsbp->icsb_fdblocks = lcounter + XFS_ALLOC_SET_ASIDE(mp);
2332 xfs_icsb_unlock_cntr(icsbp);
2340 * serialise with a mutex so we don't burn lots of cpu on
2341 * the superblock lock. We still need to hold the superblock
2342 * lock, however, when we modify the global structures.
2347 * Now running atomically.
2349 * If the counter is enabled, someone has beaten us to rebalancing.
2350 * Drop the lock and try again in the fast path....
2352 if (!(xfs_icsb_counter_disabled(mp, field))) {
2353 xfs_icsb_unlock(mp);
2358 * The counter is currently disabled. Because we are
2359 * running atomically here, we know a rebalance cannot
2360 * be in progress. Hence we can go straight to operating
2361 * on the global superblock. We do not call xfs_mod_incore_sb()
2362 * here even though we need to get the m_sb_lock. Doing so
2363 * will cause us to re-enter this function and deadlock.
2364 * Hence we get the m_sb_lock ourselves and then call
2365 * xfs_mod_incore_sb_unlocked() as the unlocked path operates
2366 * directly on the global counters.
2368 spin_lock(&mp->m_sb_lock);
2369 ret = xfs_mod_incore_sb_unlocked(mp, field, delta, rsvd);
2370 spin_unlock(&mp->m_sb_lock);
2373 * Now that we've modified the global superblock, we
2374 * may be able to re-enable the distributed counters
2375 * (e.g. lots of space just got freed). After that
2379 xfs_icsb_balance_counter(mp, field, 0);
2380 xfs_icsb_unlock(mp);
2384 xfs_icsb_unlock_cntr(icsbp);
2388 * We may have multiple threads here if multiple per-cpu
2389 * counters run dry at the same time. This will mean we can
2390 * do more balances than strictly necessary but it is not
2391 * the common slowpath case.
2396 * running atomically.
2398 * This will leave the counter in the correct state for future
2399 * accesses. After the rebalance, we simply try again and our retry
2400 * will either succeed through the fast path or slow path without
2401 * another balance operation being required.
2403 xfs_icsb_balance_counter(mp, field, delta);
2404 xfs_icsb_unlock(mp);