582 lines
14 KiB
C
582 lines
14 KiB
C
/*
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* Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "xfs.h"
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#include "xfs_fs.h"
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#include "xfs_types.h"
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#include "xfs_log.h"
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#include "xfs_inum.h"
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#include "xfs_trans.h"
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#include "xfs_sb.h"
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#include "xfs_dir.h"
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#include "xfs_dmapi.h"
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#include "xfs_mount.h"
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#include "xfs_trans_priv.h"
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#include "xfs_error.h"
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STATIC void xfs_ail_insert(xfs_ail_entry_t *, xfs_log_item_t *);
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STATIC xfs_log_item_t * xfs_ail_delete(xfs_ail_entry_t *, xfs_log_item_t *);
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STATIC xfs_log_item_t * xfs_ail_min(xfs_ail_entry_t *);
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STATIC xfs_log_item_t * xfs_ail_next(xfs_ail_entry_t *, xfs_log_item_t *);
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#ifdef DEBUG
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STATIC void xfs_ail_check(xfs_ail_entry_t *);
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#else
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#define xfs_ail_check(a)
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#endif /* DEBUG */
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/*
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* This is called by the log manager code to determine the LSN
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* of the tail of the log. This is exactly the LSN of the first
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* item in the AIL. If the AIL is empty, then this function
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* returns 0.
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*
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* We need the AIL lock in order to get a coherent read of the
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* lsn of the last item in the AIL.
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*/
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xfs_lsn_t
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xfs_trans_tail_ail(
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xfs_mount_t *mp)
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{
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xfs_lsn_t lsn;
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xfs_log_item_t *lip;
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SPLDECL(s);
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AIL_LOCK(mp,s);
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lip = xfs_ail_min(&(mp->m_ail));
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if (lip == NULL) {
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lsn = (xfs_lsn_t)0;
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} else {
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lsn = lip->li_lsn;
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}
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AIL_UNLOCK(mp, s);
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return lsn;
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}
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/*
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* xfs_trans_push_ail
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*
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* This routine is called to move the tail of the AIL
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* forward. It does this by trying to flush items in the AIL
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* whose lsns are below the given threshold_lsn.
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*
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* The routine returns the lsn of the tail of the log.
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*/
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xfs_lsn_t
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xfs_trans_push_ail(
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xfs_mount_t *mp,
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xfs_lsn_t threshold_lsn)
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{
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xfs_lsn_t lsn;
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xfs_log_item_t *lip;
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int gen;
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int restarts;
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int lock_result;
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int flush_log;
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SPLDECL(s);
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#define XFS_TRANS_PUSH_AIL_RESTARTS 10
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AIL_LOCK(mp,s);
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lip = xfs_trans_first_ail(mp, &gen);
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if (lip == NULL || XFS_FORCED_SHUTDOWN(mp)) {
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/*
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* Just return if the AIL is empty.
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*/
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AIL_UNLOCK(mp, s);
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return (xfs_lsn_t)0;
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}
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XFS_STATS_INC(xs_push_ail);
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/*
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* While the item we are looking at is below the given threshold
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* try to flush it out. Make sure to limit the number of times
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* we allow xfs_trans_next_ail() to restart scanning from the
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* beginning of the list. We'd like not to stop until we've at least
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* tried to push on everything in the AIL with an LSN less than
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* the given threshold. However, we may give up before that if
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* we realize that we've been holding the AIL_LOCK for 'too long',
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* blocking interrupts. Currently, too long is < 500us roughly.
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*/
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flush_log = 0;
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restarts = 0;
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while (((restarts < XFS_TRANS_PUSH_AIL_RESTARTS) &&
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(XFS_LSN_CMP(lip->li_lsn, threshold_lsn) < 0))) {
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/*
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* If we can lock the item without sleeping, unlock
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* the AIL lock and flush the item. Then re-grab the
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* AIL lock so we can look for the next item on the
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* AIL. Since we unlock the AIL while we flush the
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* item, the next routine may start over again at the
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* the beginning of the list if anything has changed.
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* That is what the generation count is for.
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*
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* If we can't lock the item, either its holder will flush
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* it or it is already being flushed or it is being relogged.
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* In any of these case it is being taken care of and we
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* can just skip to the next item in the list.
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*/
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lock_result = IOP_TRYLOCK(lip);
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switch (lock_result) {
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case XFS_ITEM_SUCCESS:
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AIL_UNLOCK(mp, s);
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XFS_STATS_INC(xs_push_ail_success);
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IOP_PUSH(lip);
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AIL_LOCK(mp,s);
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break;
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case XFS_ITEM_PUSHBUF:
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AIL_UNLOCK(mp, s);
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XFS_STATS_INC(xs_push_ail_pushbuf);
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#ifdef XFSRACEDEBUG
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delay_for_intr();
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delay(300);
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#endif
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ASSERT(lip->li_ops->iop_pushbuf);
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ASSERT(lip);
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IOP_PUSHBUF(lip);
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AIL_LOCK(mp,s);
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break;
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case XFS_ITEM_PINNED:
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XFS_STATS_INC(xs_push_ail_pinned);
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flush_log = 1;
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break;
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case XFS_ITEM_LOCKED:
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XFS_STATS_INC(xs_push_ail_locked);
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break;
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case XFS_ITEM_FLUSHING:
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XFS_STATS_INC(xs_push_ail_flushing);
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break;
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default:
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ASSERT(0);
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break;
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}
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lip = xfs_trans_next_ail(mp, lip, &gen, &restarts);
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if (lip == NULL) {
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break;
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}
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if (XFS_FORCED_SHUTDOWN(mp)) {
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/*
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* Just return if we shut down during the last try.
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*/
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AIL_UNLOCK(mp, s);
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return (xfs_lsn_t)0;
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}
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}
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if (flush_log) {
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/*
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* If something we need to push out was pinned, then
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* push out the log so it will become unpinned and
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* move forward in the AIL.
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*/
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AIL_UNLOCK(mp, s);
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XFS_STATS_INC(xs_push_ail_flush);
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xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE);
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AIL_LOCK(mp, s);
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}
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lip = xfs_ail_min(&(mp->m_ail));
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if (lip == NULL) {
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lsn = (xfs_lsn_t)0;
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} else {
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lsn = lip->li_lsn;
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}
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AIL_UNLOCK(mp, s);
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return lsn;
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} /* xfs_trans_push_ail */
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/*
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* This is to be called when an item is unlocked that may have
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* been in the AIL. It will wake up the first member of the AIL
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* wait list if this item's unlocking might allow it to progress.
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* If the item is in the AIL, then we need to get the AIL lock
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* while doing our checking so we don't race with someone going
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* to sleep waiting for this event in xfs_trans_push_ail().
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*/
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void
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xfs_trans_unlocked_item(
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xfs_mount_t *mp,
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xfs_log_item_t *lip)
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{
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xfs_log_item_t *min_lip;
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/*
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* If we're forcibly shutting down, we may have
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* unlocked log items arbitrarily. The last thing
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* we want to do is to move the tail of the log
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* over some potentially valid data.
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*/
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if (!(lip->li_flags & XFS_LI_IN_AIL) ||
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XFS_FORCED_SHUTDOWN(mp)) {
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return;
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}
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/*
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* This is the one case where we can call into xfs_ail_min()
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* without holding the AIL lock because we only care about the
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* case where we are at the tail of the AIL. If the object isn't
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* at the tail, it doesn't matter what result we get back. This
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* is slightly racy because since we were just unlocked, we could
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* go to sleep between the call to xfs_ail_min and the call to
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* xfs_log_move_tail, have someone else lock us, commit to us disk,
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* move us out of the tail of the AIL, and then we wake up. However,
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* the call to xfs_log_move_tail() doesn't do anything if there's
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* not enough free space to wake people up so we're safe calling it.
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*/
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min_lip = xfs_ail_min(&mp->m_ail);
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if (min_lip == lip)
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xfs_log_move_tail(mp, 1);
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} /* xfs_trans_unlocked_item */
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/*
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* Update the position of the item in the AIL with the new
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* lsn. If it is not yet in the AIL, add it. Otherwise, move
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* it to its new position by removing it and re-adding it.
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*
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* Wakeup anyone with an lsn less than the item's lsn. If the item
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* we move in the AIL is the minimum one, update the tail lsn in the
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* log manager.
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*
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* Increment the AIL's generation count to indicate that the tree
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* has changed.
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*
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* This function must be called with the AIL lock held. The lock
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* is dropped before returning, so the caller must pass in the
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* cookie returned by AIL_LOCK.
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*/
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void
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xfs_trans_update_ail(
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xfs_mount_t *mp,
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xfs_log_item_t *lip,
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xfs_lsn_t lsn,
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unsigned long s)
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{
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xfs_ail_entry_t *ailp;
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xfs_log_item_t *dlip=NULL;
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xfs_log_item_t *mlip; /* ptr to minimum lip */
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ailp = &(mp->m_ail);
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mlip = xfs_ail_min(ailp);
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if (lip->li_flags & XFS_LI_IN_AIL) {
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dlip = xfs_ail_delete(ailp, lip);
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ASSERT(dlip == lip);
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} else {
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lip->li_flags |= XFS_LI_IN_AIL;
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}
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lip->li_lsn = lsn;
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xfs_ail_insert(ailp, lip);
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mp->m_ail_gen++;
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if (mlip == dlip) {
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mlip = xfs_ail_min(&(mp->m_ail));
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AIL_UNLOCK(mp, s);
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xfs_log_move_tail(mp, mlip->li_lsn);
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} else {
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AIL_UNLOCK(mp, s);
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}
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} /* xfs_trans_update_ail */
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/*
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* Delete the given item from the AIL. It must already be in
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* the AIL.
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*
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* Wakeup anyone with an lsn less than item's lsn. If the item
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* we delete in the AIL is the minimum one, update the tail lsn in the
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* log manager.
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*
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* Clear the IN_AIL flag from the item, reset its lsn to 0, and
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* bump the AIL's generation count to indicate that the tree
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* has changed.
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*
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* This function must be called with the AIL lock held. The lock
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* is dropped before returning, so the caller must pass in the
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* cookie returned by AIL_LOCK.
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*/
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void
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xfs_trans_delete_ail(
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xfs_mount_t *mp,
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xfs_log_item_t *lip,
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unsigned long s)
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{
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xfs_ail_entry_t *ailp;
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xfs_log_item_t *dlip;
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xfs_log_item_t *mlip;
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if (lip->li_flags & XFS_LI_IN_AIL) {
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ailp = &(mp->m_ail);
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mlip = xfs_ail_min(ailp);
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dlip = xfs_ail_delete(ailp, lip);
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ASSERT(dlip == lip);
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lip->li_flags &= ~XFS_LI_IN_AIL;
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lip->li_lsn = 0;
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mp->m_ail_gen++;
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if (mlip == dlip) {
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mlip = xfs_ail_min(&(mp->m_ail));
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AIL_UNLOCK(mp, s);
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xfs_log_move_tail(mp, (mlip ? mlip->li_lsn : 0));
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} else {
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AIL_UNLOCK(mp, s);
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}
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}
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else {
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/*
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* If the file system is not being shutdown, we are in
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* serious trouble if we get to this stage.
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*/
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if (XFS_FORCED_SHUTDOWN(mp))
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AIL_UNLOCK(mp, s);
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else {
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xfs_cmn_err(XFS_PTAG_AILDELETE, CE_ALERT, mp,
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"xfs_trans_delete_ail: attempting to delete a log item that is not in the AIL");
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AIL_UNLOCK(mp, s);
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xfs_force_shutdown(mp, XFS_CORRUPT_INCORE);
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}
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}
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}
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/*
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* Return the item in the AIL with the smallest lsn.
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* Return the current tree generation number for use
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* in calls to xfs_trans_next_ail().
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*/
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xfs_log_item_t *
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xfs_trans_first_ail(
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xfs_mount_t *mp,
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int *gen)
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{
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xfs_log_item_t *lip;
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lip = xfs_ail_min(&(mp->m_ail));
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*gen = (int)mp->m_ail_gen;
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return (lip);
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}
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/*
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* If the generation count of the tree has not changed since the
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* caller last took something from the AIL, then return the elmt
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* in the tree which follows the one given. If the count has changed,
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* then return the minimum elmt of the AIL and bump the restarts counter
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* if one is given.
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*/
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xfs_log_item_t *
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xfs_trans_next_ail(
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xfs_mount_t *mp,
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xfs_log_item_t *lip,
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int *gen,
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int *restarts)
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{
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xfs_log_item_t *nlip;
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ASSERT(mp && lip && gen);
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if (mp->m_ail_gen == *gen) {
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nlip = xfs_ail_next(&(mp->m_ail), lip);
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} else {
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nlip = xfs_ail_min(&(mp->m_ail));
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*gen = (int)mp->m_ail_gen;
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if (restarts != NULL) {
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XFS_STATS_INC(xs_push_ail_restarts);
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(*restarts)++;
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}
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}
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return (nlip);
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}
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/*
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* The active item list (AIL) is a doubly linked list of log
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* items sorted by ascending lsn. The base of the list is
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* a forw/back pointer pair embedded in the xfs mount structure.
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* The base is initialized with both pointers pointing to the
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* base. This case always needs to be distinguished, because
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* the base has no lsn to look at. We almost always insert
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* at the end of the list, so on inserts we search from the
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* end of the list to find where the new item belongs.
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*/
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/*
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* Initialize the doubly linked list to point only to itself.
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*/
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void
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xfs_trans_ail_init(
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xfs_mount_t *mp)
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{
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mp->m_ail.ail_forw = (xfs_log_item_t*)&(mp->m_ail);
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mp->m_ail.ail_back = (xfs_log_item_t*)&(mp->m_ail);
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}
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/*
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* Insert the given log item into the AIL.
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* We almost always insert at the end of the list, so on inserts
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* we search from the end of the list to find where the
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* new item belongs.
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*/
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STATIC void
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xfs_ail_insert(
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xfs_ail_entry_t *base,
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xfs_log_item_t *lip)
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/* ARGSUSED */
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{
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xfs_log_item_t *next_lip;
|
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/*
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* If the list is empty, just insert the item.
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*/
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if (base->ail_back == (xfs_log_item_t*)base) {
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base->ail_forw = lip;
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base->ail_back = lip;
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lip->li_ail.ail_forw = (xfs_log_item_t*)base;
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lip->li_ail.ail_back = (xfs_log_item_t*)base;
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return;
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}
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next_lip = base->ail_back;
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while ((next_lip != (xfs_log_item_t*)base) &&
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(XFS_LSN_CMP(next_lip->li_lsn, lip->li_lsn) > 0)) {
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next_lip = next_lip->li_ail.ail_back;
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}
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ASSERT((next_lip == (xfs_log_item_t*)base) ||
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(XFS_LSN_CMP(next_lip->li_lsn, lip->li_lsn) <= 0));
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lip->li_ail.ail_forw = next_lip->li_ail.ail_forw;
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lip->li_ail.ail_back = next_lip;
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next_lip->li_ail.ail_forw = lip;
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lip->li_ail.ail_forw->li_ail.ail_back = lip;
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xfs_ail_check(base);
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return;
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}
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|
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/*
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* Delete the given item from the AIL. Return a pointer to the item.
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*/
|
|
/*ARGSUSED*/
|
|
STATIC xfs_log_item_t *
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xfs_ail_delete(
|
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xfs_ail_entry_t *base,
|
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xfs_log_item_t *lip)
|
|
/* ARGSUSED */
|
|
{
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lip->li_ail.ail_forw->li_ail.ail_back = lip->li_ail.ail_back;
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lip->li_ail.ail_back->li_ail.ail_forw = lip->li_ail.ail_forw;
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lip->li_ail.ail_forw = NULL;
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|
lip->li_ail.ail_back = NULL;
|
|
|
|
xfs_ail_check(base);
|
|
return lip;
|
|
}
|
|
|
|
/*
|
|
* Return a pointer to the first item in the AIL.
|
|
* If the AIL is empty, then return NULL.
|
|
*/
|
|
STATIC xfs_log_item_t *
|
|
xfs_ail_min(
|
|
xfs_ail_entry_t *base)
|
|
/* ARGSUSED */
|
|
{
|
|
register xfs_log_item_t *forw = base->ail_forw;
|
|
if (forw == (xfs_log_item_t*)base) {
|
|
return NULL;
|
|
}
|
|
return forw;
|
|
}
|
|
|
|
/*
|
|
* Return a pointer to the item which follows
|
|
* the given item in the AIL. If the given item
|
|
* is the last item in the list, then return NULL.
|
|
*/
|
|
STATIC xfs_log_item_t *
|
|
xfs_ail_next(
|
|
xfs_ail_entry_t *base,
|
|
xfs_log_item_t *lip)
|
|
/* ARGSUSED */
|
|
{
|
|
if (lip->li_ail.ail_forw == (xfs_log_item_t*)base) {
|
|
return NULL;
|
|
}
|
|
return lip->li_ail.ail_forw;
|
|
|
|
}
|
|
|
|
#ifdef DEBUG
|
|
/*
|
|
* Check that the list is sorted as it should be.
|
|
*/
|
|
STATIC void
|
|
xfs_ail_check(
|
|
xfs_ail_entry_t *base)
|
|
{
|
|
xfs_log_item_t *lip;
|
|
xfs_log_item_t *prev_lip;
|
|
|
|
lip = base->ail_forw;
|
|
if (lip == (xfs_log_item_t*)base) {
|
|
/*
|
|
* Make sure the pointers are correct when the list
|
|
* is empty.
|
|
*/
|
|
ASSERT(base->ail_back == (xfs_log_item_t*)base);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Walk the list checking forward and backward pointers,
|
|
* lsn ordering, and that every entry has the XFS_LI_IN_AIL
|
|
* flag set.
|
|
*/
|
|
prev_lip = (xfs_log_item_t*)base;
|
|
while (lip != (xfs_log_item_t*)base) {
|
|
if (prev_lip != (xfs_log_item_t*)base) {
|
|
ASSERT(prev_lip->li_ail.ail_forw == lip);
|
|
ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0);
|
|
}
|
|
ASSERT(lip->li_ail.ail_back == prev_lip);
|
|
ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0);
|
|
prev_lip = lip;
|
|
lip = lip->li_ail.ail_forw;
|
|
}
|
|
ASSERT(lip == (xfs_log_item_t*)base);
|
|
ASSERT(base->ail_back == prev_lip);
|
|
}
|
|
#endif /* DEBUG */
|