Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 596 insertions, 0 deletions

diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
new file mode 100644
index 000000000000..7bc5eab4c2c1
--- /dev/null
+++ b/fs/xfs/xfs_trans_ail.c
@@ -0,0 +1,596 @@
+/*
+ * 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 */