/*
* Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
+ * Copyright (c) 2008 Dave Chinner
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
#include "xfs_trans_priv.h"
#include "xfs_error.h"
-STATIC void xfs_ail_insert(xfs_ail_t *, xfs_log_item_t *);
-STATIC xfs_log_item_t * xfs_ail_delete(xfs_ail_t *, xfs_log_item_t *);
-STATIC xfs_log_item_t * xfs_ail_min(xfs_ail_t *);
-STATIC xfs_log_item_t * xfs_ail_next(xfs_ail_t *, xfs_log_item_t *);
+STATIC void xfs_ail_insert(struct xfs_ail *, xfs_log_item_t *);
+STATIC xfs_log_item_t * xfs_ail_delete(struct xfs_ail *, xfs_log_item_t *);
+STATIC xfs_log_item_t * xfs_ail_min(struct xfs_ail *);
+STATIC xfs_log_item_t * xfs_ail_next(struct xfs_ail *, xfs_log_item_t *);
#ifdef DEBUG
-STATIC void xfs_ail_check(xfs_ail_t *, xfs_log_item_t *);
+STATIC void xfs_ail_check(struct xfs_ail *, xfs_log_item_t *);
#else
#define xfs_ail_check(a,l)
#endif /* DEBUG */
* lsn of the last item in the AIL.
*/
xfs_lsn_t
-xfs_trans_tail_ail(
- xfs_mount_t *mp)
+xfs_trans_ail_tail(
+ struct xfs_ail *ailp)
{
xfs_lsn_t lsn;
xfs_log_item_t *lip;
- spin_lock(&mp->m_ail_lock);
- lip = xfs_ail_min(&mp->m_ail);
+ spin_lock(&ailp->xa_lock);
+ lip = xfs_ail_min(ailp);
if (lip == NULL) {
lsn = (xfs_lsn_t)0;
} else {
lsn = lip->li_lsn;
}
- spin_unlock(&mp->m_ail_lock);
+ spin_unlock(&ailp->xa_lock);
return lsn;
}
* any of the objects, so the lock is not needed.
*/
void
-xfs_trans_push_ail(
- xfs_mount_t *mp,
- xfs_lsn_t threshold_lsn)
+xfs_trans_ail_push(
+ struct xfs_ail *ailp,
+ xfs_lsn_t threshold_lsn)
{
- xfs_log_item_t *lip;
+ xfs_log_item_t *lip;
+
+ lip = xfs_ail_min(ailp);
+ if (lip && !XFS_FORCED_SHUTDOWN(ailp->xa_mount)) {
+ if (XFS_LSN_CMP(threshold_lsn, ailp->xa_target) > 0)
+ xfsaild_wakeup(ailp, threshold_lsn);
+ }
+}
+
+/*
+ * AIL traversal cursor initialisation.
+ *
+ * The cursor keeps track of where our current traversal is up
+ * to by tracking the next ƣtem in the list for us. However, for
+ * this to be safe, removing an object from the AIL needs to invalidate
+ * any cursor that points to it. hence the traversal cursor needs to
+ * be linked to the struct xfs_ail so that deletion can search all the
+ * active cursors for invalidation.
+ *
+ * We don't link the push cursor because it is embedded in the struct
+ * xfs_ail and hence easily findable.
+ */
+STATIC void
+xfs_trans_ail_cursor_init(
+ struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur)
+{
+ cur->item = NULL;
+ if (cur == &ailp->xa_cursors)
+ return;
+
+ cur->next = ailp->xa_cursors.next;
+ ailp->xa_cursors.next = cur;
+}
+
+/*
+ * Set the cursor to the next item, because when we look
+ * up the cursor the current item may have been freed.
+ */
+STATIC void
+xfs_trans_ail_cursor_set(
+ struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
+ struct xfs_log_item *lip)
+{
+ if (lip)
+ cur->item = xfs_ail_next(ailp, lip);
+}
+
+/*
+ * Get the next item in the traversal and advance the cursor.
+ * If the cursor was invalidated (inidicated by a lip of 1),
+ * restart the traversal.
+ */
+struct xfs_log_item *
+xfs_trans_ail_cursor_next(
+ struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur)
+{
+ struct xfs_log_item *lip = cur->item;
+
+ if ((__psint_t)lip & 1)
+ lip = xfs_ail_min(ailp);
+ xfs_trans_ail_cursor_set(ailp, cur, lip);
+ return lip;
+}
+
+/*
+ * Now that the traversal is complete, we need to remove the cursor
+ * from the list of traversing cursors. Avoid removing the embedded
+ * push cursor, but use the fact it is alway present to make the
+ * list deletion simple.
+ */
+void
+xfs_trans_ail_cursor_done(
+ struct xfs_ail *ailp,
+ struct xfs_ail_cursor *done)
+{
+ struct xfs_ail_cursor *prev = NULL;
+ struct xfs_ail_cursor *cur;
+
+ done->item = NULL;
+ if (done == &ailp->xa_cursors)
+ return;
+ prev = &ailp->xa_cursors;
+ for (cur = prev->next; cur; prev = cur, cur = prev->next) {
+ if (cur == done) {
+ prev->next = cur->next;
+ break;
+ }
+ }
+ ASSERT(cur);
+}
+
+/*
+ * Invalidate any cursor that is pointing to this item. This is
+ * called when an item is removed from the AIL. Any cursor pointing
+ * to this object is now invalid and the traversal needs to be
+ * terminated so it doesn't reference a freed object. We set the
+ * cursor item to a value of 1 so we can distinguish between an
+ * invalidation and the end of the list when getting the next item
+ * from the cursor.
+ */
+STATIC void
+xfs_trans_ail_cursor_clear(
+ struct xfs_ail *ailp,
+ struct xfs_log_item *lip)
+{
+ struct xfs_ail_cursor *cur;
- lip = xfs_ail_min(&mp->m_ail);
- if (lip && !XFS_FORCED_SHUTDOWN(mp)) {
- if (XFS_LSN_CMP(threshold_lsn, mp->m_ail.xa_target) > 0)
- xfsaild_wakeup(mp, threshold_lsn);
+ /* need to search all cursors */
+ for (cur = &ailp->xa_cursors; cur; cur = cur->next) {
+ if (cur->item == lip)
+ cur->item = (struct xfs_log_item *)
+ ((__psint_t)cur->item | 1);
}
}
* Return the current tree generation number for use
* in calls to xfs_trans_next_ail().
*/
-STATIC xfs_log_item_t *
-xfs_trans_first_push_ail(
- xfs_mount_t *mp,
- int *gen,
- xfs_lsn_t lsn)
+xfs_log_item_t *
+xfs_trans_ail_cursor_first(
+ struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
+ xfs_lsn_t lsn)
{
- xfs_log_item_t *lip;
+ xfs_log_item_t *lip;
- lip = xfs_ail_min(&mp->m_ail);
- *gen = (int)mp->m_ail.xa_gen;
+ xfs_trans_ail_cursor_init(ailp, cur);
+ lip = xfs_ail_min(ailp);
if (lsn == 0)
- return lip;
+ goto out;
- list_for_each_entry(lip, &mp->m_ail.xa_ail, li_ail) {
+ list_for_each_entry(lip, &ailp->xa_ail, li_ail) {
if (XFS_LSN_CMP(lip->li_lsn, lsn) >= 0)
- return lip;
+ goto out;
}
-
- return NULL;
+ lip = NULL;
+out:
+ xfs_trans_ail_cursor_set(ailp, cur, lip);
+ return lip;
}
/*
*/
long
xfsaild_push(
- xfs_mount_t *mp,
+ struct xfs_ail *ailp,
xfs_lsn_t *last_lsn)
{
long tout = 1000; /* milliseconds */
xfs_lsn_t last_pushed_lsn = *last_lsn;
- xfs_lsn_t target = mp->m_ail.xa_target;
+ xfs_lsn_t target = ailp->xa_target;
xfs_lsn_t lsn;
xfs_log_item_t *lip;
- int gen;
- int restarts;
int flush_log, count, stuck;
+ xfs_mount_t *mp = ailp->xa_mount;
+ struct xfs_ail_cursor *cur = &ailp->xa_cursors;
-#define XFS_TRANS_PUSH_AIL_RESTARTS 10
-
- spin_lock(&mp->m_ail_lock);
- lip = xfs_trans_first_push_ail(mp, &gen, *last_lsn);
+ spin_lock(&ailp->xa_lock);
+ xfs_trans_ail_cursor_init(ailp, cur);
+ lip = xfs_trans_ail_cursor_first(ailp, cur, *last_lsn);
if (!lip || XFS_FORCED_SHUTDOWN(mp)) {
/*
* AIL is empty or our push has reached the end.
*/
- spin_unlock(&mp->m_ail_lock);
+ xfs_trans_ail_cursor_done(ailp, cur);
+ spin_unlock(&ailp->xa_lock);
last_pushed_lsn = 0;
- goto out;
+ return tout;
}
XFS_STATS_INC(xs_push_ail);
*/
tout = 10;
lsn = lip->li_lsn;
- flush_log = stuck = count = restarts = 0;
+ flush_log = stuck = count = 0;
while ((XFS_LSN_CMP(lip->li_lsn, target) < 0)) {
int lock_result;
/*
* skip to the next item in the list.
*/
lock_result = IOP_TRYLOCK(lip);
- spin_unlock(&mp->m_ail_lock);
+ spin_unlock(&ailp->xa_lock);
switch (lock_result) {
case XFS_ITEM_SUCCESS:
XFS_STATS_INC(xs_push_ail_success);
break;
}
- spin_lock(&mp->m_ail_lock);
+ spin_lock(&ailp->xa_lock);
/* should we bother continuing? */
if (XFS_FORCED_SHUTDOWN(mp))
break;
if (stuck > 100)
break;
- lip = xfs_trans_next_ail(mp, lip, &gen, &restarts);
+ lip = xfs_trans_ail_cursor_next(ailp, cur);
if (lip == NULL)
break;
- if (restarts > XFS_TRANS_PUSH_AIL_RESTARTS)
- break;
lsn = lip->li_lsn;
}
- spin_unlock(&mp->m_ail_lock);
+ xfs_trans_ail_cursor_done(ailp, cur);
+ spin_unlock(&ailp->xa_lock);
if (flush_log) {
/*
*/
tout += 20;
last_pushed_lsn = 0;
- } else if ((restarts > XFS_TRANS_PUSH_AIL_RESTARTS) ||
- ((stuck * 100) / count > 90)) {
+ } else if ((stuck * 100) / count > 90) {
/*
* Either there is a lot of contention on the AIL or we
* are stuck due to operations in progress. "Stuck" in this
*/
tout += 10;
}
-out:
*last_lsn = last_pushed_lsn;
return tout;
} /* xfsaild_push */
*/
void
xfs_trans_unlocked_item(
- xfs_mount_t *mp,
+ struct xfs_ail *ailp,
xfs_log_item_t *lip)
{
xfs_log_item_t *min_lip;
* over some potentially valid data.
*/
if (!(lip->li_flags & XFS_LI_IN_AIL) ||
- XFS_FORCED_SHUTDOWN(mp)) {
+ XFS_FORCED_SHUTDOWN(ailp->xa_mount)) {
return;
}
* 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);
+ min_lip = xfs_ail_min(ailp);
if (min_lip == lip)
- xfs_log_move_tail(mp, 1);
+ xfs_log_move_tail(ailp->xa_mount, 1);
} /* xfs_trans_unlocked_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.
*/
void
-xfs_trans_update_ail(
- xfs_mount_t *mp,
+xfs_trans_ail_update(
+ struct xfs_ail *ailp,
xfs_log_item_t *lip,
- xfs_lsn_t lsn) __releases(mp->m_ail_lock)
+ xfs_lsn_t lsn) __releases(ailp->xa_lock)
{
- xfs_log_item_t *dlip=NULL;
+ xfs_log_item_t *dlip = NULL;
xfs_log_item_t *mlip; /* ptr to minimum lip */
- mlip = xfs_ail_min(&mp->m_ail);
+ mlip = xfs_ail_min(ailp);
if (lip->li_flags & XFS_LI_IN_AIL) {
- dlip = xfs_ail_delete(&mp->m_ail, lip);
+ dlip = xfs_ail_delete(ailp, lip);
ASSERT(dlip == lip);
+ xfs_trans_ail_cursor_clear(ailp, dlip);
} else {
lip->li_flags |= XFS_LI_IN_AIL;
}
lip->li_lsn = lsn;
-
- xfs_ail_insert(&mp->m_ail, lip);
- mp->m_ail.xa_gen++;
+ xfs_ail_insert(ailp, lip);
if (mlip == dlip) {
- mlip = xfs_ail_min(&mp->m_ail);
- spin_unlock(&mp->m_ail_lock);
- xfs_log_move_tail(mp, mlip->li_lsn);
+ mlip = xfs_ail_min(ailp);
+ spin_unlock(&ailp->xa_lock);
+ xfs_log_move_tail(ailp->xa_mount, mlip->li_lsn);
} else {
- spin_unlock(&mp->m_ail_lock);
+ spin_unlock(&ailp->xa_lock);
}
* is dropped before returning.
*/
void
-xfs_trans_delete_ail(
- xfs_mount_t *mp,
- xfs_log_item_t *lip) __releases(mp->m_ail_lock)
+xfs_trans_ail_delete(
+ struct xfs_ail *ailp,
+ xfs_log_item_t *lip) __releases(ailp->xa_lock)
{
xfs_log_item_t *dlip;
xfs_log_item_t *mlip;
if (lip->li_flags & XFS_LI_IN_AIL) {
- mlip = xfs_ail_min(&mp->m_ail);
- dlip = xfs_ail_delete(&mp->m_ail, lip);
+ mlip = xfs_ail_min(ailp);
+ dlip = xfs_ail_delete(ailp, lip);
ASSERT(dlip == lip);
+ xfs_trans_ail_cursor_clear(ailp, dlip);
lip->li_flags &= ~XFS_LI_IN_AIL;
lip->li_lsn = 0;
- mp->m_ail.xa_gen++;
if (mlip == dlip) {
- mlip = xfs_ail_min(&mp->m_ail);
- spin_unlock(&mp->m_ail_lock);
- xfs_log_move_tail(mp, (mlip ? mlip->li_lsn : 0));
+ mlip = xfs_ail_min(ailp);
+ spin_unlock(&ailp->xa_lock);
+ xfs_log_move_tail(ailp->xa_mount,
+ (mlip ? mlip->li_lsn : 0));
} else {
- spin_unlock(&mp->m_ail_lock);
+ spin_unlock(&ailp->xa_lock);
}
}
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))
- spin_unlock(&mp->m_ail_lock);
- else {
+ struct xfs_mount *mp = ailp->xa_mount;
+
+ spin_unlock(&ailp->xa_lock);
+ if (!XFS_FORCED_SHUTDOWN(mp)) {
xfs_cmn_err(XFS_PTAG_AILDELETE, CE_ALERT, mp,
"%s: attempting to delete a log item that is not in the AIL",
- __FUNCTION__);
- spin_unlock(&mp->m_ail_lock);
+ __func__);
xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
}
}
/*
- * 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.xa_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.xa_gen == *gen) {
- nlip = xfs_ail_next(&mp->m_ail, lip);
- } else {
- nlip = xfs_ail_min(&mp->m_ail);
- *gen = (int)mp->m_ail.xa_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.
xfs_trans_ail_init(
xfs_mount_t *mp)
{
- INIT_LIST_HEAD(&mp->m_ail.xa_ail);
- return xfsaild_start(mp);
+ struct xfs_ail *ailp;
+ int error;
+
+ ailp = kmem_zalloc(sizeof(struct xfs_ail), KM_MAYFAIL);
+ if (!ailp)
+ return ENOMEM;
+
+ ailp->xa_mount = mp;
+ INIT_LIST_HEAD(&ailp->xa_ail);
+ spin_lock_init(&ailp->xa_lock);
+ error = xfsaild_start(ailp);
+ if (error)
+ goto out_free_ailp;
+ mp->m_ail = ailp;
+ return 0;
+
+out_free_ailp:
+ kmem_free(ailp);
+ return error;
}
void
xfs_trans_ail_destroy(
xfs_mount_t *mp)
{
- xfsaild_stop(mp);
+ struct xfs_ail *ailp = mp->m_ail;
+
+ xfsaild_stop(ailp);
+ kmem_free(ailp);
}
/*
*/
STATIC void
xfs_ail_insert(
- xfs_ail_t *ailp,
+ struct xfs_ail *ailp,
xfs_log_item_t *lip)
/* ARGSUSED */
{
/*ARGSUSED*/
STATIC xfs_log_item_t *
xfs_ail_delete(
- xfs_ail_t *ailp,
+ struct xfs_ail *ailp,
xfs_log_item_t *lip)
/* ARGSUSED */
{
*/
STATIC xfs_log_item_t *
xfs_ail_min(
- xfs_ail_t *ailp)
+ struct xfs_ail *ailp)
/* ARGSUSED */
{
if (list_empty(&ailp->xa_ail))
*/
STATIC xfs_log_item_t *
xfs_ail_next(
- xfs_ail_t *ailp,
+ struct xfs_ail *ailp,
xfs_log_item_t *lip)
/* ARGSUSED */
{
*/
STATIC void
xfs_ail_check(
- xfs_ail_t *ailp,
+ struct xfs_ail *ailp,
xfs_log_item_t *lip)
{
xfs_log_item_t *prev_lip;
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