git.oblomov.eu Git - linux-2.6/blob - fs/xfs/linux-2.6/xfs_sync.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_btree.h"
  34 #include "xfs_dir2_sf.h"
  35 #include "xfs_attr_sf.h"
  36 #include "xfs_inode.h"
  37 #include "xfs_dinode.h"
  38 #include "xfs_error.h"
  39 #include "xfs_mru_cache.h"
  40 #include "xfs_filestream.h"
  41 #include "xfs_vnodeops.h"
  42 #include "xfs_utils.h"
  43 #include "xfs_buf_item.h"
  44 #include "xfs_inode_item.h"
  45 #include "xfs_rw.h"
  46
  47 #include <linux/kthread.h>
  48 #include <linux/freezer.h>
  49
  50 /*
  51  * xfs_sync flushes any pending I/O to file system vfsp.
  52  *
  53  * This routine is called by vfs_sync() to make sure that things make it
  54  * out to disk eventually, on sync() system calls to flush out everything,
  55  * and when the file system is unmounted.  For the vfs_sync() case, all
  56  * we really need to do is sync out the log to make all of our meta-data
  57  * updates permanent (except for timestamps).  For calls from pflushd(),
  58  * dirty pages are kept moving by calling pdflush() on the inodes
  59  * containing them.  We also flush the inodes that we can lock without
  60  * sleeping and the superblock if we can lock it without sleeping from
  61  * vfs_sync() so that items at the tail of the log are always moving out.
  62  *
  63  * Flags:
  64  *      SYNC_BDFLUSH - We're being called from vfs_sync() so we don't want
  65  *                     to sleep if we can help it.  All we really need
  66  *                     to do is ensure that the log is synced at least
  67  *                     periodically.  We also push the inodes and
  68  *                     superblock if we can lock them without sleeping
  69  *                      and they are not pinned.
  70  *      SYNC_ATTR    - We need to flush the inodes.  If SYNC_BDFLUSH is not
  71  *                     set, then we really want to lock each inode and flush
  72  *                     it.
  73  *      SYNC_WAIT    - All the flushes that take place in this call should
  74  *                     be synchronous.
  75  *      SYNC_DELWRI  - This tells us to push dirty pages associated with
  76  *                     inodes.  SYNC_WAIT and SYNC_BDFLUSH are used to
  77  *                     determine if they should be flushed sync, async, or
  78  *                     delwri.
  79  *      SYNC_CLOSE   - This flag is passed when the system is being
  80  *                     unmounted.  We should sync and invalidate everything.
  81  *      SYNC_FSDATA  - This indicates that the caller would like to make
  82  *                     sure the superblock is safe on disk.  We can ensure
  83  *                     this by simply making sure the log gets flushed
  84  *                     if SYNC_BDFLUSH is set, and by actually writing it
  85  *                     out otherwise.
  86  *      SYNC_IOWAIT  - The caller wants us to wait for all data I/O to complete
  87  *                     before we return (including direct I/O). Forms the drain
  88  *                     side of the write barrier needed to safely quiesce the
  89  *                     filesystem.
  90  *
  91  */
  92 int
  93 xfs_sync(
  94         xfs_mount_t     *mp,
  95         int             flags)
  96 {
  97         int             error;
  98
  99         /*
 100          * Get the Quota Manager to flush the dquots.
 101          *
 102          * If XFS quota support is not enabled or this filesystem
 103          * instance does not use quotas XFS_QM_DQSYNC will always
 104          * return zero.
 105          */
 106         error = XFS_QM_DQSYNC(mp, flags);
 107         if (error) {
 108                 /*
 109                  * If we got an IO error, we will be shutting down.
 110                  * So, there's nothing more for us to do here.
 111                  */
 112                 ASSERT(error != EIO || XFS_FORCED_SHUTDOWN(mp));
 113                 if (XFS_FORCED_SHUTDOWN(mp))
 114                         return XFS_ERROR(error);
 115         }
 116
 117         if (flags & SYNC_IOWAIT)
 118                 xfs_filestream_flush(mp);
 119
 120         return xfs_syncsub(mp, flags, NULL);
 121 }
 122
 123 /*
 124  * Sync all the inodes in the given AG according to the
 125  * direction given by the flags.
 126  */
 127 STATIC int
 128 xfs_sync_inodes_ag(
 129         xfs_mount_t     *mp,
 130         int             ag,
 131         int             flags,
 132         int             *bypassed)
 133 {
 134         xfs_inode_t     *ip = NULL;
 135         struct inode    *vp = NULL;
 136         xfs_perag_t     *pag = &mp->m_perag[ag];
 137         boolean_t       vnode_refed = B_FALSE;
 138         int             nr_found;
 139         int             first_index = 0;
 140         int             error = 0;
 141         int             last_error = 0;
 142         int             fflag = XFS_B_ASYNC;
 143         int             lock_flags = XFS_ILOCK_SHARED;
 144
 145         if (flags & SYNC_DELWRI)
 146                 fflag = XFS_B_DELWRI;
 147         if (flags & SYNC_WAIT)
 148                 fflag = 0;              /* synchronous overrides all */
 149
 150         if (flags & (SYNC_DELWRI | SYNC_CLOSE)) {
 151                 /*
 152                  * We need the I/O lock if we're going to call any of
 153                  * the flush/inval routines.
 154                  */
 155                 lock_flags |= XFS_IOLOCK_SHARED;
 156         }
 157
 158         do {
 159                 /*
 160                  * use a gang lookup to find the next inode in the tree
 161                  * as the tree is sparse and a gang lookup walks to find
 162                  * the number of objects requested.
 163                  */
 164                 read_lock(&pag->pag_ici_lock);
 165                 nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
 166                                 (void**)&ip, first_index, 1);
 167
 168                 if (!nr_found) {
 169                         read_unlock(&pag->pag_ici_lock);
 170                         break;
 171                 }
 172
 173                 /* update the index for the next lookup */
 174                 first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
 175
 176                 /*
 177                  * skip inodes in reclaim. Let xfs_syncsub do that for
 178                  * us so we don't need to worry.
 179                  */
 180                 vp = VFS_I(ip);
 181                 if (!vp) {
 182                         read_unlock(&pag->pag_ici_lock);
 183                         continue;
 184                 }
 185
 186                 /* bad inodes are dealt with elsewhere */
 187                 if (VN_BAD(vp)) {
 188                         read_unlock(&pag->pag_ici_lock);
 189                         continue;
 190                 }
 191
 192                 /* nothing to sync during shutdown */
 193                 if (XFS_FORCED_SHUTDOWN(mp) && !(flags & SYNC_CLOSE)) {
 194                         read_unlock(&pag->pag_ici_lock);
 195                         return 0;
 196                 }
 197
 198                 /*
 199                  * The inode lock here actually coordinates with the almost
 200                  * spurious inode lock in xfs_ireclaim() to prevent the vnode
 201                  * we handle here without a reference from being freed while we
 202                  * reference it.  If we lock the inode while it's on the mount
 203                  * list here, then the spurious inode lock in xfs_ireclaim()
 204                  * after the inode is pulled from the mount list will sleep
 205                  * until we release it here.  This keeps the vnode from being
 206                  * freed while we reference it.
 207                  */
 208                 if (xfs_ilock_nowait(ip, lock_flags) == 0) {
 209                         vp = vn_grab(vp);
 210                         read_unlock(&pag->pag_ici_lock);
 211                         if (!vp)
 212                                 continue;
 213                         xfs_ilock(ip, lock_flags);
 214
 215                         ASSERT(vp == VFS_I(ip));
 216                         ASSERT(ip->i_mount == mp);
 217
 218                         vnode_refed = B_TRUE;
 219                 } else {
 220                         /* safe to unlock here as we have a reference */
 221                         read_unlock(&pag->pag_ici_lock);
 222                 }
 223                 /*
 224                  * If we have to flush data or wait for I/O completion
 225                  * we need to drop the ilock that we currently hold.
 226                  * If we need to drop the lock, insert a marker if we
 227                  * have not already done so.
 228                  */
 229                 if (flags & SYNC_CLOSE) {
 230                         xfs_iunlock(ip, XFS_ILOCK_SHARED);
 231                         if (XFS_FORCED_SHUTDOWN(mp))
 232                                 xfs_tosspages(ip, 0, -1, FI_REMAPF);
 233                         else
 234                                 error = xfs_flushinval_pages(ip, 0, -1,
 235                                                         FI_REMAPF);
 236                         /* wait for I/O on freeze */
 237                         if (flags & SYNC_IOWAIT)
 238                                 vn_iowait(ip);
 239
 240                         xfs_ilock(ip, XFS_ILOCK_SHARED);
 241                 }
 242
 243                 if ((flags & SYNC_DELWRI) && VN_DIRTY(vp)) {
 244                         xfs_iunlock(ip, XFS_ILOCK_SHARED);
 245                         error = xfs_flush_pages(ip, 0, -1, fflag, FI_NONE);
 246                         if (flags & SYNC_IOWAIT)
 247                                 vn_iowait(ip);
 248                         xfs_ilock(ip, XFS_ILOCK_SHARED);
 249                 }
 250
 251                 if ((flags & SYNC_ATTR) && !xfs_inode_clean(ip)) {
 252                         if (flags & SYNC_WAIT) {
 253                                 xfs_iflock(ip);
 254                                 if (!xfs_inode_clean(ip))
 255                                         error = xfs_iflush(ip, XFS_IFLUSH_SYNC);
 256                                 else
 257                                         xfs_ifunlock(ip);
 258                         } else if (xfs_iflock_nowait(ip)) {
 259                                 if (!xfs_inode_clean(ip))
 260                                         error = xfs_iflush(ip, XFS_IFLUSH_DELWRI);
 261                                 else
 262                                         xfs_ifunlock(ip);
 263                         } else if (bypassed) {
 264                                 (*bypassed)++;
 265                         }
 266                 }
 267
 268                 if (lock_flags)
 269                         xfs_iunlock(ip, lock_flags);
 270
 271                 if (vnode_refed) {
 272                         IRELE(ip);
 273                         vnode_refed = B_FALSE;
 274                 }
 275
 276                 if (error)
 277                         last_error = error;
 278                 /*
 279                  * bail out if the filesystem is corrupted.
 280                  */
 281                 if (error == EFSCORRUPTED)
 282                         return XFS_ERROR(error);
 283
 284         } while (nr_found);
 285
 286         return last_error;
 287 }
 288
 289 int
 290 xfs_sync_inodes(
 291         xfs_mount_t     *mp,
 292         int             flags,
 293         int             *bypassed)
 294 {
 295         int             error;
 296         int             last_error;
 297         int             i;
 298
 299         if (bypassed)
 300                 *bypassed = 0;
 301         if (mp->m_flags & XFS_MOUNT_RDONLY)
 302                 return 0;
 303         error = 0;
 304         last_error = 0;
 305
 306         for (i = 0; i < mp->m_sb.sb_agcount; i++) {
 307                 if (!mp->m_perag[i].pag_ici_init)
 308                         continue;
 309                 error = xfs_sync_inodes_ag(mp, i, flags, bypassed);
 310                 if (error)
 311                         last_error = error;
 312                 if (error == EFSCORRUPTED)
 313                         break;
 314         }
 315         return XFS_ERROR(last_error);
 316 }
 317
 318 /*
 319  * xfs sync routine for internal use
 320  *
 321  * This routine supports all of the flags defined for the generic vfs_sync
 322  * interface as explained above under xfs_sync.
 323  *
 324  */
 325 int
 326 xfs_syncsub(
 327         xfs_mount_t     *mp,
 328         int             flags,
 329         int             *bypassed)
 330 {
 331         int             error = 0;
 332         int             last_error = 0;
 333         uint            log_flags = XFS_LOG_FORCE;
 334         xfs_buf_t       *bp;
 335         xfs_buf_log_item_t      *bip;
 336
 337         /*
 338          * Sync out the log.  This ensures that the log is periodically
 339          * flushed even if there is not enough activity to fill it up.
 340          */
 341         if (flags & SYNC_WAIT)
 342                 log_flags |= XFS_LOG_SYNC;
 343
 344         xfs_log_force(mp, (xfs_lsn_t)0, log_flags);
 345
 346         if (flags & (SYNC_ATTR|SYNC_DELWRI)) {
 347                 if (flags & SYNC_BDFLUSH)
 348                         xfs_finish_reclaim_all(mp, 1, XFS_IFLUSH_DELWRI_ELSE_ASYNC);
 349                 else
 350                         error = xfs_sync_inodes(mp, flags, bypassed);
 351         }
 352
 353         /*
 354          * Flushing out dirty data above probably generated more
 355          * log activity, so if this isn't vfs_sync() then flush
 356          * the log again.
 357          */
 358         if (flags & SYNC_DELWRI) {
 359                 xfs_log_force(mp, (xfs_lsn_t)0, log_flags);
 360         }
 361
 362         if (flags & SYNC_FSDATA) {
 363                 /*
 364                  * If this is vfs_sync() then only sync the superblock
 365                  * if we can lock it without sleeping and it is not pinned.
 366                  */
 367                 if (flags & SYNC_BDFLUSH) {
 368                         bp = xfs_getsb(mp, XFS_BUF_TRYLOCK);
 369                         if (bp != NULL) {
 370                                 bip = XFS_BUF_FSPRIVATE(bp,xfs_buf_log_item_t*);
 371                                 if ((bip != NULL) &&
 372                                     xfs_buf_item_dirty(bip)) {
 373                                         if (!(XFS_BUF_ISPINNED(bp))) {
 374                                                 XFS_BUF_ASYNC(bp);
 375                                                 error = xfs_bwrite(mp, bp);
 376                                         } else {
 377                                                 xfs_buf_relse(bp);
 378                                         }
 379                                 } else {
 380                                         xfs_buf_relse(bp);
 381                                 }
 382                         }
 383                 } else {
 384                         bp = xfs_getsb(mp, 0);
 385                         /*
 386                          * If the buffer is pinned then push on the log so
 387                          * we won't get stuck waiting in the write for
 388                          * someone, maybe ourselves, to flush the log.
 389                          * Even though we just pushed the log above, we
 390                          * did not have the superblock buffer locked at
 391                          * that point so it can become pinned in between
 392                          * there and here.
 393                          */
 394                         if (XFS_BUF_ISPINNED(bp))
 395                                 xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE);
 396                         if (flags & SYNC_WAIT)
 397                                 XFS_BUF_UNASYNC(bp);
 398                         else
 399                                 XFS_BUF_ASYNC(bp);
 400                         error = xfs_bwrite(mp, bp);
 401                 }
 402                 if (error) {
 403                         last_error = error;
 404                 }
 405         }
 406
 407         /*
 408          * Now check to see if the log needs a "dummy" transaction.
 409          */
 410         if (!(flags & SYNC_REMOUNT) && xfs_log_need_covered(mp)) {
 411                 xfs_trans_t *tp;
 412                 xfs_inode_t *ip;
 413
 414                 /*
 415                  * Put a dummy transaction in the log to tell
 416                  * recovery that all others are OK.
 417                  */
 418                 tp = xfs_trans_alloc(mp, XFS_TRANS_DUMMY1);
 419                 if ((error = xfs_trans_reserve(tp, 0,
 420                                 XFS_ICHANGE_LOG_RES(mp),
 421                                 0, 0, 0)))  {
 422                         xfs_trans_cancel(tp, 0);
 423                         return error;
 424                 }
 425
 426                 ip = mp->m_rootip;
 427                 xfs_ilock(ip, XFS_ILOCK_EXCL);
 428
 429                 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 430                 xfs_trans_ihold(tp, ip);
 431                 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 432                 error = xfs_trans_commit(tp, 0);
 433                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
 434                 xfs_log_force(mp, (xfs_lsn_t)0, log_flags);
 435         }
 436
 437         /*
 438          * When shutting down, we need to insure that the AIL is pushed
 439          * to disk or the filesystem can appear corrupt from the PROM.
 440          */
 441         if ((flags & (SYNC_CLOSE|SYNC_WAIT)) == (SYNC_CLOSE|SYNC_WAIT)) {
 442                 XFS_bflush(mp->m_ddev_targp);
 443                 if (mp->m_rtdev_targp) {
 444                         XFS_bflush(mp->m_rtdev_targp);
 445                 }
 446         }
 447
 448         return XFS_ERROR(last_error);
 449 }
 450
 451 /*
 452  * Enqueue a work item to be picked up by the vfs xfssyncd thread.
 453  * Doing this has two advantages:
 454  * - It saves on stack space, which is tight in certain situations
 455  * - It can be used (with care) as a mechanism to avoid deadlocks.
 456  * Flushing while allocating in a full filesystem requires both.
 457  */
 458 STATIC void
 459 xfs_syncd_queue_work(
 460         struct xfs_mount *mp,
 461         void            *data,
 462         void            (*syncer)(struct xfs_mount *, void *))
 463 {
 464         struct bhv_vfs_sync_work *work;
 465
 466         work = kmem_alloc(sizeof(struct bhv_vfs_sync_work), KM_SLEEP);
 467         INIT_LIST_HEAD(&work->w_list);
 468         work->w_syncer = syncer;
 469         work->w_data = data;
 470         work->w_mount = mp;
 471         spin_lock(&mp->m_sync_lock);
 472         list_add_tail(&work->w_list, &mp->m_sync_list);
 473         spin_unlock(&mp->m_sync_lock);
 474         wake_up_process(mp->m_sync_task);
 475 }
 476
 477 /*
 478  * Flush delayed allocate data, attempting to free up reserved space
 479  * from existing allocations.  At this point a new allocation attempt
 480  * has failed with ENOSPC and we are in the process of scratching our
 481  * heads, looking about for more room...
 482  */
 483 STATIC void
 484 xfs_flush_inode_work(
 485         struct xfs_mount *mp,
 486         void            *arg)
 487 {
 488         struct inode    *inode = arg;
 489         filemap_flush(inode->i_mapping);
 490         iput(inode);
 491 }
 492
 493 void
 494 xfs_flush_inode(
 495         xfs_inode_t     *ip)
 496 {
 497         struct inode    *inode = VFS_I(ip);
 498
 499         igrab(inode);
 500         xfs_syncd_queue_work(ip->i_mount, inode, xfs_flush_inode_work);
 501         delay(msecs_to_jiffies(500));
 502 }
 503
 504 /*
 505  * This is the "bigger hammer" version of xfs_flush_inode_work...
 506  * (IOW, "If at first you don't succeed, use a Bigger Hammer").
 507  */
 508 STATIC void
 509 xfs_flush_device_work(
 510         struct xfs_mount *mp,
 511         void            *arg)
 512 {
 513         struct inode    *inode = arg;
 514         sync_blockdev(mp->m_super->s_bdev);
 515         iput(inode);
 516 }
 517
 518 void
 519 xfs_flush_device(
 520         xfs_inode_t     *ip)
 521 {
 522         struct inode    *inode = VFS_I(ip);
 523
 524         igrab(inode);
 525         xfs_syncd_queue_work(ip->i_mount, inode, xfs_flush_device_work);
 526         delay(msecs_to_jiffies(500));
 527         xfs_log_force(ip->i_mount, (xfs_lsn_t)0, XFS_LOG_FORCE|XFS_LOG_SYNC);
 528 }
 529
 530 STATIC void
 531 xfs_sync_worker(
 532         struct xfs_mount *mp,
 533         void            *unused)
 534 {
 535         int             error;
 536
 537         if (!(mp->m_flags & XFS_MOUNT_RDONLY))
 538                 error = xfs_sync(mp, SYNC_FSDATA | SYNC_BDFLUSH | SYNC_ATTR);
 539         mp->m_sync_seq++;
 540         wake_up(&mp->m_wait_single_sync_task);
 541 }
 542
 543 STATIC int
 544 xfssyncd(
 545         void                    *arg)
 546 {
 547         struct xfs_mount        *mp = arg;
 548         long                    timeleft;
 549         bhv_vfs_sync_work_t     *work, *n;
 550         LIST_HEAD               (tmp);
 551
 552         set_freezable();
 553         timeleft = xfs_syncd_centisecs * msecs_to_jiffies(10);
 554         for (;;) {
 555                 timeleft = schedule_timeout_interruptible(timeleft);
 556                 /* swsusp */
 557                 try_to_freeze();
 558                 if (kthread_should_stop() && list_empty(&mp->m_sync_list))
 559                         break;
 560
 561                 spin_lock(&mp->m_sync_lock);
 562                 /*
 563                  * We can get woken by laptop mode, to do a sync -
 564                  * that's the (only!) case where the list would be
 565                  * empty with time remaining.
 566                  */
 567                 if (!timeleft || list_empty(&mp->m_sync_list)) {
 568                         if (!timeleft)
 569                                 timeleft = xfs_syncd_centisecs *
 570                                                         msecs_to_jiffies(10);
 571                         INIT_LIST_HEAD(&mp->m_sync_work.w_list);
 572                         list_add_tail(&mp->m_sync_work.w_list,
 573                                         &mp->m_sync_list);
 574                 }
 575                 list_for_each_entry_safe(work, n, &mp->m_sync_list, w_list)
 576                         list_move(&work->w_list, &tmp);
 577                 spin_unlock(&mp->m_sync_lock);
 578
 579                 list_for_each_entry_safe(work, n, &tmp, w_list) {
 580                         (*work->w_syncer)(mp, work->w_data);
 581                         list_del(&work->w_list);
 582                         if (work == &mp->m_sync_work)
 583                                 continue;
 584                         kmem_free(work);
 585                 }
 586         }
 587
 588         return 0;
 589 }
 590
 591 int
 592 xfs_syncd_init(
 593         struct xfs_mount        *mp)
 594 {
 595         mp->m_sync_work.w_syncer = xfs_sync_worker;
 596         mp->m_sync_work.w_mount = mp;
 597         mp->m_sync_task = kthread_run(xfssyncd, mp, "xfssyncd");
 598         if (IS_ERR(mp->m_sync_task))
 599                 return -PTR_ERR(mp->m_sync_task);
 600         return 0;
 601 }
 602
 603 void
 604 xfs_syncd_stop(
 605         struct xfs_mount        *mp)
 606 {
 607         kthread_stop(mp->m_sync_task);
 608 }
 609