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diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
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+/*
+ * Copyright (c) 2000-2002 Silicon Graphics, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Further, this software is distributed without any warranty that it is
+ * free of the rightful claim of any third person regarding infringement
+ * or the like. Any license provided herein, whether implied or
+ * otherwise, applies only to this software file. Patent licenses, if
+ * any, provided herein do not apply to combinations of this program with
+ * other software, or any other product whatsoever.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
+ * Mountain View, CA 94043, or:
+ *
+ * http://www.sgi.com
+ *
+ * For further information regarding this notice, see:
+ *
+ * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
+ */
+
+#include "xfs.h"
+#include "xfs_macros.h"
+#include "xfs_types.h"
+#include "xfs_inum.h"
+#include "xfs_log.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_dir.h"
+#include "xfs_dmapi.h"
+#include "xfs_mount.h"
+#include "xfs_trans_priv.h"
+#include "xfs_error.h"
+
+STATIC void xfs_ail_insert(xfs_ail_entry_t *, xfs_log_item_t *);
+STATIC xfs_log_item_t * xfs_ail_delete(xfs_ail_entry_t *, xfs_log_item_t *);
+STATIC xfs_log_item_t * xfs_ail_min(xfs_ail_entry_t *);
+STATIC xfs_log_item_t * xfs_ail_next(xfs_ail_entry_t *, xfs_log_item_t *);
+
+#ifdef DEBUG
+STATIC void xfs_ail_check(xfs_ail_entry_t *);
+#else
+#define xfs_ail_check(a)
+#endif /* DEBUG */
+
+
+/*
+ * This is called by the log manager code to determine the LSN
+ * of the tail of the log. This is exactly the LSN of the first
+ * item in the AIL. If the AIL is empty, then this function
+ * returns 0.
+ *
+ * We need the AIL lock in order to get a coherent read of the
+ * lsn of the last item in the AIL.
+ */
+xfs_lsn_t
+xfs_trans_tail_ail(
+ xfs_mount_t *mp)
+{
+ xfs_lsn_t lsn;
+ xfs_log_item_t *lip;
+ SPLDECL(s);
+
+ AIL_LOCK(mp,s);
+ lip = xfs_ail_min(&(mp->m_ail));
+ if (lip == NULL) {
+ lsn = (xfs_lsn_t)0;
+ } else {
+ lsn = lip->li_lsn;
+ }
+ AIL_UNLOCK(mp, s);
+
+ return lsn;
+}
+
+/*
+ * xfs_trans_push_ail
+ *
+ * This routine is called to move the tail of the AIL
+ * forward. It does this by trying to flush items in the AIL
+ * whose lsns are below the given threshold_lsn.
+ *
+ * The routine returns the lsn of the tail of the log.
+ */
+xfs_lsn_t
+xfs_trans_push_ail(
+ xfs_mount_t *mp,
+ xfs_lsn_t threshold_lsn)
+{
+ xfs_lsn_t lsn;
+ xfs_log_item_t *lip;
+ int gen;
+ int restarts;
+ int lock_result;
+ int flush_log;
+ SPLDECL(s);
+
+#define XFS_TRANS_PUSH_AIL_RESTARTS 10
+
+ AIL_LOCK(mp,s);
+ lip = xfs_trans_first_ail(mp, &gen);
+ if (lip == NULL || XFS_FORCED_SHUTDOWN(mp)) {
+ /*
+ * Just return if the AIL is empty.
+ */
+ AIL_UNLOCK(mp, s);
+ return (xfs_lsn_t)0;
+ }
+
+ XFS_STATS_INC(xs_push_ail);
+
+ /*
+ * While the item we are looking at is below the given threshold
+ * try to flush it out. Make sure to limit the number of times
+ * we allow xfs_trans_next_ail() to restart scanning from the
+ * beginning of the list. We'd like not to stop until we've at least
+ * tried to push on everything in the AIL with an LSN less than
+ * the given threshold. However, we may give up before that if
+ * we realize that we've been holding the AIL_LOCK for 'too long',
+ * blocking interrupts. Currently, too long is < 500us roughly.
+ */
+ flush_log = 0;
+ restarts = 0;
+ while (((restarts < XFS_TRANS_PUSH_AIL_RESTARTS) &&
+ (XFS_LSN_CMP(lip->li_lsn, threshold_lsn) < 0))) {
+ /*
+ * If we can lock the item without sleeping, unlock
+ * the AIL lock and flush the item. Then re-grab the
+ * AIL lock so we can look for the next item on the
+ * AIL. Since we unlock the AIL while we flush the
+ * item, the next routine may start over again at the
+ * the beginning of the list if anything has changed.
+ * That is what the generation count is for.
+ *
+ * If we can't lock the item, either its holder will flush
+ * it or it is already being flushed or it is being relogged.
+ * In any of these case it is being taken care of and we
+ * can just skip to the next item in the list.
+ */
+ lock_result = IOP_TRYLOCK(lip);
+ switch (lock_result) {
+ case XFS_ITEM_SUCCESS:
+ AIL_UNLOCK(mp, s);
+ XFS_STATS_INC(xs_push_ail_success);
+ IOP_PUSH(lip);
+ AIL_LOCK(mp,s);
+ break;
+
+ case XFS_ITEM_PUSHBUF:
+ AIL_UNLOCK(mp, s);
+ XFS_STATS_INC(xs_push_ail_pushbuf);
+#ifdef XFSRACEDEBUG
+ delay_for_intr();
+ delay(300);
+#endif
+ ASSERT(lip->li_ops->iop_pushbuf);
+ ASSERT(lip);
+ IOP_PUSHBUF(lip);
+ AIL_LOCK(mp,s);
+ break;
+
+ case XFS_ITEM_PINNED:
+ XFS_STATS_INC(xs_push_ail_pinned);
+ flush_log = 1;
+ break;
+
+ case XFS_ITEM_LOCKED:
+ XFS_STATS_INC(xs_push_ail_locked);
+ break;
+
+ case XFS_ITEM_FLUSHING:
+ XFS_STATS_INC(xs_push_ail_flushing);
+ break;
+
+ default:
+ ASSERT(0);
+ break;
+ }
+
+ lip = xfs_trans_next_ail(mp, lip, &gen, &restarts);
+ if (lip == NULL) {
+ break;
+ }
+ if (XFS_FORCED_SHUTDOWN(mp)) {
+ /*
+ * Just return if we shut down during the last try.
+ */
+ AIL_UNLOCK(mp, s);
+ return (xfs_lsn_t)0;
+ }
+
+ }
+
+ if (flush_log) {
+ /*
+ * If something we need to push out was pinned, then
+ * push out the log so it will become unpinned and
+ * move forward in the AIL.
+ */
+ AIL_UNLOCK(mp, s);
+ XFS_STATS_INC(xs_push_ail_flush);
+ xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE);
+ AIL_LOCK(mp, s);
+ }
+
+ lip = xfs_ail_min(&(mp->m_ail));
+ if (lip == NULL) {
+ lsn = (xfs_lsn_t)0;
+ } else {
+ lsn = lip->li_lsn;
+ }
+
+ AIL_UNLOCK(mp, s);
+ return lsn;
+} /* xfs_trans_push_ail */
+
+
+/*
+ * This is to be called when an item is unlocked that may have
+ * been in the AIL. It will wake up the first member of the AIL
+ * wait list if this item's unlocking might allow it to progress.
+ * If the item is in the AIL, then we need to get the AIL lock
+ * while doing our checking so we don't race with someone going
+ * to sleep waiting for this event in xfs_trans_push_ail().
+ */
+void
+xfs_trans_unlocked_item(
+ xfs_mount_t *mp,
+ xfs_log_item_t *lip)
+{
+ xfs_log_item_t *min_lip;
+
+ /*
+ * If we're forcibly shutting down, we may have
+ * unlocked log items arbitrarily. The last thing
+ * we want to do is to move the tail of the log
+ * over some potentially valid data.
+ */
+ if (!(lip->li_flags & XFS_LI_IN_AIL) ||
+ XFS_FORCED_SHUTDOWN(mp)) {
+ return;
+ }
+
+ /*
+ * This is the one case where we can call into xfs_ail_min()
+ * without holding the AIL lock because we only care about the
+ * case where we are at the tail of the AIL. If the object isn't
+ * at the tail, it doesn't matter what result we get back. This
+ * is slightly racy because since we were just unlocked, we could
+ * go to sleep between the call to xfs_ail_min and the call to
+ * xfs_log_move_tail, have someone else lock us, commit to us disk,
+ * move us out of the tail of the AIL, and then we wake up. However,
+ * the call to xfs_log_move_tail() doesn't do anything if there's
+ * not enough free space to wake people up so we're safe calling it.
+ */
+ min_lip = xfs_ail_min(&mp->m_ail);
+
+ if (min_lip == lip)
+ xfs_log_move_tail(mp, 1);
+} /* xfs_trans_unlocked_item */
+
+
+/*
+ * Update the position of the item in the AIL with the new
+ * lsn. If it is not yet in the AIL, add it. Otherwise, move
+ * it to its new position by removing it and re-adding it.
+ *
+ * Wakeup anyone with an lsn less than the item's lsn. If the item
+ * we move in the AIL is the minimum one, update the tail lsn in the
+ * log manager.
+ *
+ * Increment the AIL's generation count to indicate that the tree
+ * has changed.
+ *
+ * This function must be called with the AIL lock held. The lock
+ * is dropped before returning, so the caller must pass in the
+ * cookie returned by AIL_LOCK.
+ */
+void
+xfs_trans_update_ail(
+ xfs_mount_t *mp,
+ xfs_log_item_t *lip,
+ xfs_lsn_t lsn,
+ unsigned long s)
+{
+ xfs_ail_entry_t *ailp;
+ xfs_log_item_t *dlip=NULL;
+ xfs_log_item_t *mlip; /* ptr to minimum lip */
+
+ ailp = &(mp->m_ail);
+ mlip = xfs_ail_min(ailp);
+
+ if (lip->li_flags & XFS_LI_IN_AIL) {
+ dlip = xfs_ail_delete(ailp, lip);
+ ASSERT(dlip == lip);
+ } else {
+ lip->li_flags |= XFS_LI_IN_AIL;
+ }
+
+ lip->li_lsn = lsn;
+
+ xfs_ail_insert(ailp, lip);
+ mp->m_ail_gen++;
+
+ if (mlip == dlip) {
+ mlip = xfs_ail_min(&(mp->m_ail));
+ AIL_UNLOCK(mp, s);
+ xfs_log_move_tail(mp, mlip->li_lsn);
+ } else {
+ AIL_UNLOCK(mp, s);
+ }
+
+
+} /* xfs_trans_update_ail */
+
+/*
+ * Delete the given item from the AIL. It must already be in
+ * the AIL.
+ *
+ * Wakeup anyone with an lsn less than item's lsn. If the item
+ * we delete in the AIL is the minimum one, update the tail lsn in the
+ * log manager.
+ *
+ * Clear the IN_AIL flag from the item, reset its lsn to 0, and
+ * bump the AIL's generation count to indicate that the tree
+ * has changed.
+ *
+ * This function must be called with the AIL lock held. The lock
+ * is dropped before returning, so the caller must pass in the
+ * cookie returned by AIL_LOCK.
+ */
+void
+xfs_trans_delete_ail(
+ xfs_mount_t *mp,
+ xfs_log_item_t *lip,
+ unsigned long s)
+{
+ xfs_ail_entry_t *ailp;
+ xfs_log_item_t *dlip;
+ xfs_log_item_t *mlip;
+
+ if (lip->li_flags & XFS_LI_IN_AIL) {
+ ailp = &(mp->m_ail);
+ mlip = xfs_ail_min(ailp);
+ dlip = xfs_ail_delete(ailp, lip);
+ ASSERT(dlip == lip);
+
+
+ lip->li_flags &= ~XFS_LI_IN_AIL;
+ lip->li_lsn = 0;
+ mp->m_ail_gen++;
+
+ if (mlip == dlip) {
+ mlip = xfs_ail_min(&(mp->m_ail));
+ AIL_UNLOCK(mp, s);
+ xfs_log_move_tail(mp, (mlip ? mlip->li_lsn : 0));
+ } else {
+ AIL_UNLOCK(mp, s);
+ }
+ }
+ else {
+ /*
+ * If the file system is not being shutdown, we are in
+ * serious trouble if we get to this stage.
+ */
+ if (XFS_FORCED_SHUTDOWN(mp))
+ AIL_UNLOCK(mp, s);
+ else {
+ xfs_cmn_err(XFS_PTAG_AILDELETE, CE_ALERT, mp,
+ "xfs_trans_delete_ail: attempting to delete a log item that is not in the AIL");
+ xfs_force_shutdown(mp, XFS_CORRUPT_INCORE);
+ AIL_UNLOCK(mp, s);
+ }
+ }
+}
+
+
+
+/*
+ * Return the item in the AIL with the smallest lsn.
+ * Return the current tree generation number for use
+ * in calls to xfs_trans_next_ail().
+ */
+xfs_log_item_t *
+xfs_trans_first_ail(
+ xfs_mount_t *mp,
+ int *gen)
+{
+ xfs_log_item_t *lip;
+
+ lip = xfs_ail_min(&(mp->m_ail));
+ *gen = (int)mp->m_ail_gen;
+
+ return (lip);
+}
+
+/*
+ * If the generation count of the tree has not changed since the
+ * caller last took something from the AIL, then return the elmt
+ * in the tree which follows the one given. If the count has changed,
+ * then return the minimum elmt of the AIL and bump the restarts counter
+ * if one is given.
+ */
+xfs_log_item_t *
+xfs_trans_next_ail(
+ xfs_mount_t *mp,
+ xfs_log_item_t *lip,
+ int *gen,
+ int *restarts)
+{
+ xfs_log_item_t *nlip;
+
+ ASSERT(mp && lip && gen);
+ if (mp->m_ail_gen == *gen) {
+ nlip = xfs_ail_next(&(mp->m_ail), lip);
+ } else {
+ nlip = xfs_ail_min(&(mp->m_ail));
+ *gen = (int)mp->m_ail_gen;
+ if (restarts != NULL) {
+ XFS_STATS_INC(xs_push_ail_restarts);
+ (*restarts)++;
+ }
+ }
+
+ return (nlip);
+}
+
+
+/*
+ * The active item list (AIL) is a doubly linked list of log
+ * items sorted by ascending lsn. The base of the list is
+ * a forw/back pointer pair embedded in the xfs mount structure.
+ * The base is initialized with both pointers pointing to the
+ * base. This case always needs to be distinguished, because
+ * the base has no lsn to look at. We almost always insert
+ * at the end of the list, so on inserts we search from the
+ * end of the list to find where the new item belongs.
+ */
+
+/*
+ * Initialize the doubly linked list to point only to itself.
+ */
+void
+xfs_trans_ail_init(
+ xfs_mount_t *mp)
+{
+ mp->m_ail.ail_forw = (xfs_log_item_t*)&(mp->m_ail);
+ mp->m_ail.ail_back = (xfs_log_item_t*)&(mp->m_ail);
+}
+
+/*
+ * Insert the given log item into the AIL.
+ * We almost always insert at the end of the list, so on inserts
+ * we search from the end of the list to find where the
+ * new item belongs.
+ */
+STATIC void
+xfs_ail_insert(
+ xfs_ail_entry_t *base,
+ xfs_log_item_t *lip)
+/* ARGSUSED */
+{
+ xfs_log_item_t *next_lip;
+
+ /*
+ * If the list is empty, just insert the item.
+ */
+ if (base->ail_back == (xfs_log_item_t*)base) {
+ base->ail_forw = lip;
+ base->ail_back = lip;
+ lip->li_ail.ail_forw = (xfs_log_item_t*)base;
+ lip->li_ail.ail_back = (xfs_log_item_t*)base;
+ return;
+ }
+
+ next_lip = base->ail_back;
+ while ((next_lip != (xfs_log_item_t*)base) &&
+ (XFS_LSN_CMP(next_lip->li_lsn, lip->li_lsn) > 0)) {
+ next_lip = next_lip->li_ail.ail_back;
+ }
+ ASSERT((next_lip == (xfs_log_item_t*)base) ||
+ (XFS_LSN_CMP(next_lip->li_lsn, lip->li_lsn) <= 0));
+ lip->li_ail.ail_forw = next_lip->li_ail.ail_forw;
+ lip->li_ail.ail_back = next_lip;
+ next_lip->li_ail.ail_forw = lip;
+ lip->li_ail.ail_forw->li_ail.ail_back = lip;
+
+ xfs_ail_check(base);
+ return;
+}
+
+/*
+ * Delete the given item from the AIL. Return a pointer to the item.
+ */
+/*ARGSUSED*/
+STATIC xfs_log_item_t *
+xfs_ail_delete(
+ xfs_ail_entry_t *base,
+ xfs_log_item_t *lip)
+/* ARGSUSED */
+{
+ lip->li_ail.ail_forw->li_ail.ail_back = lip->li_ail.ail_back;
+ lip->li_ail.ail_back->li_ail.ail_forw = lip->li_ail.ail_forw;
+ lip->li_ail.ail_forw = NULL;
+ 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 */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-07 14:44:38 +0000