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-rw-r--r--fs/xfs/xfs_trans_ail.c936
1 files changed, 936 insertions, 0 deletions
diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
new file mode 100644
index 000000000..1098452e7
--- /dev/null
+++ b/fs/xfs/xfs_trans_ail.c
@@ -0,0 +1,936 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
+ * Copyright (c) 2008 Dave Chinner
+ * All Rights Reserved.
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_trans.h"
+#include "xfs_trans_priv.h"
+#include "xfs_trace.h"
+#include "xfs_errortag.h"
+#include "xfs_error.h"
+#include "xfs_log.h"
+#include "xfs_log_priv.h"
+
+#ifdef DEBUG
+/*
+ * Check that the list is sorted as it should be.
+ *
+ * Called with the ail lock held, but we don't want to assert fail with it
+ * held otherwise we'll lock everything up and won't be able to debug the
+ * cause. Hence we sample and check the state under the AIL lock and return if
+ * everything is fine, otherwise we drop the lock and run the ASSERT checks.
+ * Asserts may not be fatal, so pick the lock back up and continue onwards.
+ */
+STATIC void
+xfs_ail_check(
+ struct xfs_ail *ailp,
+ struct xfs_log_item *lip)
+ __must_hold(&ailp->ail_lock)
+{
+ struct xfs_log_item *prev_lip;
+ struct xfs_log_item *next_lip;
+ xfs_lsn_t prev_lsn = NULLCOMMITLSN;
+ xfs_lsn_t next_lsn = NULLCOMMITLSN;
+ xfs_lsn_t lsn;
+ bool in_ail;
+
+
+ if (list_empty(&ailp->ail_head))
+ return;
+
+ /*
+ * Sample then check the next and previous entries are valid.
+ */
+ in_ail = test_bit(XFS_LI_IN_AIL, &lip->li_flags);
+ prev_lip = list_entry(lip->li_ail.prev, struct xfs_log_item, li_ail);
+ if (&prev_lip->li_ail != &ailp->ail_head)
+ prev_lsn = prev_lip->li_lsn;
+ next_lip = list_entry(lip->li_ail.next, struct xfs_log_item, li_ail);
+ if (&next_lip->li_ail != &ailp->ail_head)
+ next_lsn = next_lip->li_lsn;
+ lsn = lip->li_lsn;
+
+ if (in_ail &&
+ (prev_lsn == NULLCOMMITLSN || XFS_LSN_CMP(prev_lsn, lsn) <= 0) &&
+ (next_lsn == NULLCOMMITLSN || XFS_LSN_CMP(next_lsn, lsn) >= 0))
+ return;
+
+ spin_unlock(&ailp->ail_lock);
+ ASSERT(in_ail);
+ ASSERT(prev_lsn == NULLCOMMITLSN || XFS_LSN_CMP(prev_lsn, lsn) <= 0);
+ ASSERT(next_lsn == NULLCOMMITLSN || XFS_LSN_CMP(next_lsn, lsn) >= 0);
+ spin_lock(&ailp->ail_lock);
+}
+#else /* !DEBUG */
+#define xfs_ail_check(a,l)
+#endif /* DEBUG */
+
+/*
+ * Return a pointer to the last item in the AIL. If the AIL is empty, then
+ * return NULL.
+ */
+static struct xfs_log_item *
+xfs_ail_max(
+ struct xfs_ail *ailp)
+{
+ if (list_empty(&ailp->ail_head))
+ return NULL;
+
+ return list_entry(ailp->ail_head.prev, struct xfs_log_item, li_ail);
+}
+
+/*
+ * 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 struct xfs_log_item *
+xfs_ail_next(
+ struct xfs_ail *ailp,
+ struct xfs_log_item *lip)
+{
+ if (lip->li_ail.next == &ailp->ail_head)
+ return NULL;
+
+ return list_first_entry(&lip->li_ail, struct xfs_log_item, li_ail);
+}
+
+/*
+ * 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.
+ */
+static xfs_lsn_t
+__xfs_ail_min_lsn(
+ struct xfs_ail *ailp)
+{
+ struct xfs_log_item *lip = xfs_ail_min(ailp);
+
+ if (lip)
+ return lip->li_lsn;
+ return 0;
+}
+
+xfs_lsn_t
+xfs_ail_min_lsn(
+ struct xfs_ail *ailp)
+{
+ xfs_lsn_t lsn;
+
+ spin_lock(&ailp->ail_lock);
+ lsn = __xfs_ail_min_lsn(ailp);
+ spin_unlock(&ailp->ail_lock);
+
+ return lsn;
+}
+
+/*
+ * Return the maximum lsn held in the AIL, or zero if the AIL is empty.
+ */
+static xfs_lsn_t
+xfs_ail_max_lsn(
+ struct xfs_ail *ailp)
+{
+ xfs_lsn_t lsn = 0;
+ struct xfs_log_item *lip;
+
+ spin_lock(&ailp->ail_lock);
+ lip = xfs_ail_max(ailp);
+ if (lip)
+ lsn = lip->li_lsn;
+ spin_unlock(&ailp->ail_lock);
+
+ return lsn;
+}
+
+/*
+ * The cursor keeps track of where our current traversal is up to by tracking
+ * the next item 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.
+ */
+STATIC void
+xfs_trans_ail_cursor_init(
+ struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur)
+{
+ cur->item = NULL;
+ list_add_tail(&cur->list, &ailp->ail_cursors);
+}
+
+/*
+ * Get the next item in the traversal and advance the cursor. If the cursor
+ * was invalidated (indicated 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 ((uintptr_t)lip & 1)
+ lip = xfs_ail_min(ailp);
+ if (lip)
+ cur->item = xfs_ail_next(ailp, lip);
+ return lip;
+}
+
+/*
+ * When the traversal is complete, we need to remove the cursor from the list
+ * of traversing cursors.
+ */
+void
+xfs_trans_ail_cursor_done(
+ struct xfs_ail_cursor *cur)
+{
+ cur->item = NULL;
+ list_del_init(&cur->list);
+}
+
+/*
+ * 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 low bit of the cursor item pointer 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;
+
+ list_for_each_entry(cur, &ailp->ail_cursors, list) {
+ if (cur->item == lip)
+ cur->item = (struct xfs_log_item *)
+ ((uintptr_t)cur->item | 1);
+ }
+}
+
+/*
+ * Find the first item in the AIL with the given @lsn by searching in ascending
+ * LSN order and initialise the cursor to point to the next item for a
+ * ascending traversal. Pass a @lsn of zero to initialise the cursor to the
+ * first item in the AIL. Returns NULL if the list is empty.
+ */
+struct xfs_log_item *
+xfs_trans_ail_cursor_first(
+ struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
+ xfs_lsn_t lsn)
+{
+ struct xfs_log_item *lip;
+
+ xfs_trans_ail_cursor_init(ailp, cur);
+
+ if (lsn == 0) {
+ lip = xfs_ail_min(ailp);
+ goto out;
+ }
+
+ list_for_each_entry(lip, &ailp->ail_head, li_ail) {
+ if (XFS_LSN_CMP(lip->li_lsn, lsn) >= 0)
+ goto out;
+ }
+ return NULL;
+
+out:
+ if (lip)
+ cur->item = xfs_ail_next(ailp, lip);
+ return lip;
+}
+
+static struct xfs_log_item *
+__xfs_trans_ail_cursor_last(
+ struct xfs_ail *ailp,
+ xfs_lsn_t lsn)
+{
+ struct xfs_log_item *lip;
+
+ list_for_each_entry_reverse(lip, &ailp->ail_head, li_ail) {
+ if (XFS_LSN_CMP(lip->li_lsn, lsn) <= 0)
+ return lip;
+ }
+ return NULL;
+}
+
+/*
+ * Find the last item in the AIL with the given @lsn by searching in descending
+ * LSN order and initialise the cursor to point to that item. If there is no
+ * item with the value of @lsn, then it sets the cursor to the last item with an
+ * LSN lower than @lsn. Returns NULL if the list is empty.
+ */
+struct xfs_log_item *
+xfs_trans_ail_cursor_last(
+ struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
+ xfs_lsn_t lsn)
+{
+ xfs_trans_ail_cursor_init(ailp, cur);
+ cur->item = __xfs_trans_ail_cursor_last(ailp, lsn);
+ return cur->item;
+}
+
+/*
+ * Splice the log item list into the AIL at the given LSN. We splice to the
+ * tail of the given LSN to maintain insert order for push traversals. The
+ * cursor is optional, allowing repeated updates to the same LSN to avoid
+ * repeated traversals. This should not be called with an empty list.
+ */
+static void
+xfs_ail_splice(
+ struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
+ struct list_head *list,
+ xfs_lsn_t lsn)
+{
+ struct xfs_log_item *lip;
+
+ ASSERT(!list_empty(list));
+
+ /*
+ * Use the cursor to determine the insertion point if one is
+ * provided. If not, or if the one we got is not valid,
+ * find the place in the AIL where the items belong.
+ */
+ lip = cur ? cur->item : NULL;
+ if (!lip || (uintptr_t)lip & 1)
+ lip = __xfs_trans_ail_cursor_last(ailp, lsn);
+
+ /*
+ * If a cursor is provided, we know we're processing the AIL
+ * in lsn order, and future items to be spliced in will
+ * follow the last one being inserted now. Update the
+ * cursor to point to that last item, now while we have a
+ * reliable pointer to it.
+ */
+ if (cur)
+ cur->item = list_entry(list->prev, struct xfs_log_item, li_ail);
+
+ /*
+ * Finally perform the splice. Unless the AIL was empty,
+ * lip points to the item in the AIL _after_ which the new
+ * items should go. If lip is null the AIL was empty, so
+ * the new items go at the head of the AIL.
+ */
+ if (lip)
+ list_splice(list, &lip->li_ail);
+ else
+ list_splice(list, &ailp->ail_head);
+}
+
+/*
+ * Delete the given item from the AIL. Return a pointer to the item.
+ */
+static void
+xfs_ail_delete(
+ struct xfs_ail *ailp,
+ struct xfs_log_item *lip)
+{
+ xfs_ail_check(ailp, lip);
+ list_del(&lip->li_ail);
+ xfs_trans_ail_cursor_clear(ailp, lip);
+}
+
+/*
+ * Requeue a failed buffer for writeback.
+ *
+ * We clear the log item failed state here as well, but we have to be careful
+ * about reference counts because the only active reference counts on the buffer
+ * may be the failed log items. Hence if we clear the log item failed state
+ * before queuing the buffer for IO we can release all active references to
+ * the buffer and free it, leading to use after free problems in
+ * xfs_buf_delwri_queue. It makes no difference to the buffer or log items which
+ * order we process them in - the buffer is locked, and we own the buffer list
+ * so nothing on them is going to change while we are performing this action.
+ *
+ * Hence we can safely queue the buffer for IO before we clear the failed log
+ * item state, therefore always having an active reference to the buffer and
+ * avoiding the transient zero-reference state that leads to use-after-free.
+ */
+static inline int
+xfsaild_resubmit_item(
+ struct xfs_log_item *lip,
+ struct list_head *buffer_list)
+{
+ struct xfs_buf *bp = lip->li_buf;
+
+ if (!xfs_buf_trylock(bp))
+ return XFS_ITEM_LOCKED;
+
+ if (!xfs_buf_delwri_queue(bp, buffer_list)) {
+ xfs_buf_unlock(bp);
+ return XFS_ITEM_FLUSHING;
+ }
+
+ /* protected by ail_lock */
+ list_for_each_entry(lip, &bp->b_li_list, li_bio_list) {
+ if (bp->b_flags & _XBF_INODES)
+ clear_bit(XFS_LI_FAILED, &lip->li_flags);
+ else
+ xfs_clear_li_failed(lip);
+ }
+
+ xfs_buf_unlock(bp);
+ return XFS_ITEM_SUCCESS;
+}
+
+static inline uint
+xfsaild_push_item(
+ struct xfs_ail *ailp,
+ struct xfs_log_item *lip)
+{
+ /*
+ * If log item pinning is enabled, skip the push and track the item as
+ * pinned. This can help induce head-behind-tail conditions.
+ */
+ if (XFS_TEST_ERROR(false, ailp->ail_log->l_mp, XFS_ERRTAG_LOG_ITEM_PIN))
+ return XFS_ITEM_PINNED;
+
+ /*
+ * Consider the item pinned if a push callback is not defined so the
+ * caller will force the log. This should only happen for intent items
+ * as they are unpinned once the associated done item is committed to
+ * the on-disk log.
+ */
+ if (!lip->li_ops->iop_push)
+ return XFS_ITEM_PINNED;
+ if (test_bit(XFS_LI_FAILED, &lip->li_flags))
+ return xfsaild_resubmit_item(lip, &ailp->ail_buf_list);
+ return lip->li_ops->iop_push(lip, &ailp->ail_buf_list);
+}
+
+static long
+xfsaild_push(
+ struct xfs_ail *ailp)
+{
+ struct xfs_mount *mp = ailp->ail_log->l_mp;
+ struct xfs_ail_cursor cur;
+ struct xfs_log_item *lip;
+ xfs_lsn_t lsn;
+ xfs_lsn_t target = NULLCOMMITLSN;
+ long tout;
+ int stuck = 0;
+ int flushing = 0;
+ int count = 0;
+
+ /*
+ * If we encountered pinned items or did not finish writing out all
+ * buffers the last time we ran, force a background CIL push to get the
+ * items unpinned in the near future. We do not wait on the CIL push as
+ * that could stall us for seconds if there is enough background IO
+ * load. Stalling for that long when the tail of the log is pinned and
+ * needs flushing will hard stop the transaction subsystem when log
+ * space runs out.
+ */
+ if (ailp->ail_log_flush && ailp->ail_last_pushed_lsn == 0 &&
+ (!list_empty_careful(&ailp->ail_buf_list) ||
+ xfs_ail_min_lsn(ailp))) {
+ ailp->ail_log_flush = 0;
+
+ XFS_STATS_INC(mp, xs_push_ail_flush);
+ xlog_cil_flush(ailp->ail_log);
+ }
+
+ spin_lock(&ailp->ail_lock);
+
+ /*
+ * If we have a sync push waiter, we always have to push till the AIL is
+ * empty. Update the target to point to the end of the AIL so that
+ * capture updates that occur after the sync push waiter has gone to
+ * sleep.
+ */
+ if (waitqueue_active(&ailp->ail_empty)) {
+ lip = xfs_ail_max(ailp);
+ if (lip)
+ target = lip->li_lsn;
+ } else {
+ /* barrier matches the ail_target update in xfs_ail_push() */
+ smp_rmb();
+ target = ailp->ail_target;
+ ailp->ail_target_prev = target;
+ }
+
+ /* we're done if the AIL is empty or our push has reached the end */
+ lip = xfs_trans_ail_cursor_first(ailp, &cur, ailp->ail_last_pushed_lsn);
+ if (!lip)
+ goto out_done;
+
+ XFS_STATS_INC(mp, xs_push_ail);
+
+ ASSERT(target != NULLCOMMITLSN);
+
+ lsn = lip->li_lsn;
+ while ((XFS_LSN_CMP(lip->li_lsn, target) <= 0)) {
+ int lock_result;
+
+ /*
+ * Note that iop_push may unlock and reacquire the AIL lock. We
+ * rely on the AIL cursor implementation to be able to deal with
+ * the dropped lock.
+ */
+ lock_result = xfsaild_push_item(ailp, lip);
+ switch (lock_result) {
+ case XFS_ITEM_SUCCESS:
+ XFS_STATS_INC(mp, xs_push_ail_success);
+ trace_xfs_ail_push(lip);
+
+ ailp->ail_last_pushed_lsn = lsn;
+ break;
+
+ case XFS_ITEM_FLUSHING:
+ /*
+ * The item or its backing buffer is already being
+ * flushed. The typical reason for that is that an
+ * inode buffer is locked because we already pushed the
+ * updates to it as part of inode clustering.
+ *
+ * We do not want to stop flushing just because lots
+ * of items are already being flushed, but we need to
+ * re-try the flushing relatively soon if most of the
+ * AIL is being flushed.
+ */
+ XFS_STATS_INC(mp, xs_push_ail_flushing);
+ trace_xfs_ail_flushing(lip);
+
+ flushing++;
+ ailp->ail_last_pushed_lsn = lsn;
+ break;
+
+ case XFS_ITEM_PINNED:
+ XFS_STATS_INC(mp, xs_push_ail_pinned);
+ trace_xfs_ail_pinned(lip);
+
+ stuck++;
+ ailp->ail_log_flush++;
+ break;
+ case XFS_ITEM_LOCKED:
+ XFS_STATS_INC(mp, xs_push_ail_locked);
+ trace_xfs_ail_locked(lip);
+
+ stuck++;
+ break;
+ default:
+ ASSERT(0);
+ break;
+ }
+
+ count++;
+
+ /*
+ * Are there too many items we can't do anything with?
+ *
+ * If we are skipping too many items because we can't flush
+ * them or they are already being flushed, we back off and
+ * given them time to complete whatever operation is being
+ * done. i.e. remove pressure from the AIL while we can't make
+ * progress so traversals don't slow down further inserts and
+ * removals to/from the AIL.
+ *
+ * The value of 100 is an arbitrary magic number based on
+ * observation.
+ */
+ if (stuck > 100)
+ break;
+
+ lip = xfs_trans_ail_cursor_next(ailp, &cur);
+ if (lip == NULL)
+ break;
+ lsn = lip->li_lsn;
+ }
+
+out_done:
+ xfs_trans_ail_cursor_done(&cur);
+ spin_unlock(&ailp->ail_lock);
+
+ if (xfs_buf_delwri_submit_nowait(&ailp->ail_buf_list))
+ ailp->ail_log_flush++;
+
+ if (!count || XFS_LSN_CMP(lsn, target) >= 0) {
+ /*
+ * We reached the target or the AIL is empty, so wait a bit
+ * longer for I/O to complete and remove pushed items from the
+ * AIL before we start the next scan from the start of the AIL.
+ */
+ tout = 50;
+ ailp->ail_last_pushed_lsn = 0;
+ } else if (((stuck + flushing) * 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 case
+ * is defined as >90% of the items we tried to push were stuck.
+ *
+ * Backoff a bit more to allow some I/O to complete before
+ * restarting from the start of the AIL. This prevents us from
+ * spinning on the same items, and if they are pinned will all
+ * the restart to issue a log force to unpin the stuck items.
+ */
+ tout = 20;
+ ailp->ail_last_pushed_lsn = 0;
+ } else {
+ /*
+ * Assume we have more work to do in a short while.
+ */
+ tout = 10;
+ }
+
+ return tout;
+}
+
+static int
+xfsaild(
+ void *data)
+{
+ struct xfs_ail *ailp = data;
+ long tout = 0; /* milliseconds */
+ unsigned int noreclaim_flag;
+
+ noreclaim_flag = memalloc_noreclaim_save();
+ set_freezable();
+
+ while (1) {
+ if (tout && tout <= 20)
+ set_current_state(TASK_KILLABLE|TASK_FREEZABLE);
+ else
+ set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
+
+ /*
+ * Check kthread_should_stop() after we set the task state to
+ * guarantee that we either see the stop bit and exit or the
+ * task state is reset to runnable such that it's not scheduled
+ * out indefinitely and detects the stop bit at next iteration.
+ * A memory barrier is included in above task state set to
+ * serialize again kthread_stop().
+ */
+ if (kthread_should_stop()) {
+ __set_current_state(TASK_RUNNING);
+
+ /*
+ * The caller forces out the AIL before stopping the
+ * thread in the common case, which means the delwri
+ * queue is drained. In the shutdown case, the queue may
+ * still hold relogged buffers that haven't been
+ * submitted because they were pinned since added to the
+ * queue.
+ *
+ * Log I/O error processing stales the underlying buffer
+ * and clears the delwri state, expecting the buf to be
+ * removed on the next submission attempt. That won't
+ * happen if we're shutting down, so this is the last
+ * opportunity to release such buffers from the queue.
+ */
+ ASSERT(list_empty(&ailp->ail_buf_list) ||
+ xlog_is_shutdown(ailp->ail_log));
+ xfs_buf_delwri_cancel(&ailp->ail_buf_list);
+ break;
+ }
+
+ spin_lock(&ailp->ail_lock);
+
+ /*
+ * Idle if the AIL is empty and we are not racing with a target
+ * update. We check the AIL after we set the task to a sleep
+ * state to guarantee that we either catch an ail_target update
+ * or that a wake_up resets the state to TASK_RUNNING.
+ * Otherwise, we run the risk of sleeping indefinitely.
+ *
+ * The barrier matches the ail_target update in xfs_ail_push().
+ */
+ smp_rmb();
+ if (!xfs_ail_min(ailp) &&
+ ailp->ail_target == ailp->ail_target_prev &&
+ list_empty(&ailp->ail_buf_list)) {
+ spin_unlock(&ailp->ail_lock);
+ schedule();
+ tout = 0;
+ continue;
+ }
+ spin_unlock(&ailp->ail_lock);
+
+ if (tout)
+ schedule_timeout(msecs_to_jiffies(tout));
+
+ __set_current_state(TASK_RUNNING);
+
+ try_to_freeze();
+
+ tout = xfsaild_push(ailp);
+ }
+
+ memalloc_noreclaim_restore(noreclaim_flag);
+ return 0;
+}
+
+/*
+ * 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 push is run asynchronously in a workqueue, which means the caller needs
+ * to handle waiting on the async flush for space to become available.
+ * We don't want to interrupt any push that is in progress, hence we only queue
+ * work if we set the pushing bit appropriately.
+ *
+ * We do this unlocked - we only need to know whether there is anything in the
+ * AIL at the time we are called. We don't need to access the contents of
+ * any of the objects, so the lock is not needed.
+ */
+void
+xfs_ail_push(
+ struct xfs_ail *ailp,
+ xfs_lsn_t threshold_lsn)
+{
+ struct xfs_log_item *lip;
+
+ lip = xfs_ail_min(ailp);
+ if (!lip || xlog_is_shutdown(ailp->ail_log) ||
+ XFS_LSN_CMP(threshold_lsn, ailp->ail_target) <= 0)
+ return;
+
+ /*
+ * Ensure that the new target is noticed in push code before it clears
+ * the XFS_AIL_PUSHING_BIT.
+ */
+ smp_wmb();
+ xfs_trans_ail_copy_lsn(ailp, &ailp->ail_target, &threshold_lsn);
+ smp_wmb();
+
+ wake_up_process(ailp->ail_task);
+}
+
+/*
+ * Push out all items in the AIL immediately
+ */
+void
+xfs_ail_push_all(
+ struct xfs_ail *ailp)
+{
+ xfs_lsn_t threshold_lsn = xfs_ail_max_lsn(ailp);
+
+ if (threshold_lsn)
+ xfs_ail_push(ailp, threshold_lsn);
+}
+
+/*
+ * Push out all items in the AIL immediately and wait until the AIL is empty.
+ */
+void
+xfs_ail_push_all_sync(
+ struct xfs_ail *ailp)
+{
+ DEFINE_WAIT(wait);
+
+ spin_lock(&ailp->ail_lock);
+ while (xfs_ail_max(ailp) != NULL) {
+ prepare_to_wait(&ailp->ail_empty, &wait, TASK_UNINTERRUPTIBLE);
+ wake_up_process(ailp->ail_task);
+ spin_unlock(&ailp->ail_lock);
+ schedule();
+ spin_lock(&ailp->ail_lock);
+ }
+ spin_unlock(&ailp->ail_lock);
+
+ finish_wait(&ailp->ail_empty, &wait);
+}
+
+void
+xfs_ail_update_finish(
+ struct xfs_ail *ailp,
+ xfs_lsn_t old_lsn) __releases(ailp->ail_lock)
+{
+ struct xlog *log = ailp->ail_log;
+
+ /* if the tail lsn hasn't changed, don't do updates or wakeups. */
+ if (!old_lsn || old_lsn == __xfs_ail_min_lsn(ailp)) {
+ spin_unlock(&ailp->ail_lock);
+ return;
+ }
+
+ if (!xlog_is_shutdown(log))
+ xlog_assign_tail_lsn_locked(log->l_mp);
+
+ if (list_empty(&ailp->ail_head))
+ wake_up_all(&ailp->ail_empty);
+ spin_unlock(&ailp->ail_lock);
+ xfs_log_space_wake(log->l_mp);
+}
+
+/*
+ * xfs_trans_ail_update - bulk AIL insertion operation.
+ *
+ * @xfs_trans_ail_update takes an array of log items that all need to be
+ * positioned at the same LSN in the AIL. If an item is not in the AIL, it will
+ * be added. Otherwise, it will be repositioned by removing it and re-adding
+ * it to the AIL. If we move the first item in the AIL, update the log tail to
+ * match the new minimum LSN in the AIL.
+ *
+ * This function takes the AIL lock once to execute the update operations on
+ * all the items in the array, and as such should not be called with the AIL
+ * lock held. As a result, once we have the AIL lock, we need to check each log
+ * item LSN to confirm it needs to be moved forward in the AIL.
+ *
+ * To optimise the insert operation, we delete all the items from the AIL in
+ * the first pass, moving them into a temporary list, then splice the temporary
+ * list into the correct position in the AIL. This avoids needing to do an
+ * insert operation on every item.
+ *
+ * This function must be called with the AIL lock held. The lock is dropped
+ * before returning.
+ */
+void
+xfs_trans_ail_update_bulk(
+ struct xfs_ail *ailp,
+ struct xfs_ail_cursor *cur,
+ struct xfs_log_item **log_items,
+ int nr_items,
+ xfs_lsn_t lsn) __releases(ailp->ail_lock)
+{
+ struct xfs_log_item *mlip;
+ xfs_lsn_t tail_lsn = 0;
+ int i;
+ LIST_HEAD(tmp);
+
+ ASSERT(nr_items > 0); /* Not required, but true. */
+ mlip = xfs_ail_min(ailp);
+
+ for (i = 0; i < nr_items; i++) {
+ struct xfs_log_item *lip = log_items[i];
+ if (test_and_set_bit(XFS_LI_IN_AIL, &lip->li_flags)) {
+ /* check if we really need to move the item */
+ if (XFS_LSN_CMP(lsn, lip->li_lsn) <= 0)
+ continue;
+
+ trace_xfs_ail_move(lip, lip->li_lsn, lsn);
+ if (mlip == lip && !tail_lsn)
+ tail_lsn = lip->li_lsn;
+
+ xfs_ail_delete(ailp, lip);
+ } else {
+ trace_xfs_ail_insert(lip, 0, lsn);
+ }
+ lip->li_lsn = lsn;
+ list_add_tail(&lip->li_ail, &tmp);
+ }
+
+ if (!list_empty(&tmp))
+ xfs_ail_splice(ailp, cur, &tmp, lsn);
+
+ xfs_ail_update_finish(ailp, tail_lsn);
+}
+
+/* Insert a log item into the AIL. */
+void
+xfs_trans_ail_insert(
+ struct xfs_ail *ailp,
+ struct xfs_log_item *lip,
+ xfs_lsn_t lsn)
+{
+ spin_lock(&ailp->ail_lock);
+ xfs_trans_ail_update_bulk(ailp, NULL, &lip, 1, lsn);
+}
+
+/*
+ * Delete one log item from the AIL.
+ *
+ * If this item was at the tail of the AIL, return the LSN of the log item so
+ * that we can use it to check if the LSN of the tail of the log has moved
+ * when finishing up the AIL delete process in xfs_ail_update_finish().
+ */
+xfs_lsn_t
+xfs_ail_delete_one(
+ struct xfs_ail *ailp,
+ struct xfs_log_item *lip)
+{
+ struct xfs_log_item *mlip = xfs_ail_min(ailp);
+ xfs_lsn_t lsn = lip->li_lsn;
+
+ trace_xfs_ail_delete(lip, mlip->li_lsn, lip->li_lsn);
+ xfs_ail_delete(ailp, lip);
+ clear_bit(XFS_LI_IN_AIL, &lip->li_flags);
+ lip->li_lsn = 0;
+
+ if (mlip == lip)
+ return lsn;
+ return 0;
+}
+
+void
+xfs_trans_ail_delete(
+ struct xfs_log_item *lip,
+ int shutdown_type)
+{
+ struct xfs_ail *ailp = lip->li_ailp;
+ struct xlog *log = ailp->ail_log;
+ xfs_lsn_t tail_lsn;
+
+ spin_lock(&ailp->ail_lock);
+ if (!test_bit(XFS_LI_IN_AIL, &lip->li_flags)) {
+ spin_unlock(&ailp->ail_lock);
+ if (shutdown_type && !xlog_is_shutdown(log)) {
+ xfs_alert_tag(log->l_mp, XFS_PTAG_AILDELETE,
+ "%s: attempting to delete a log item that is not in the AIL",
+ __func__);
+ xlog_force_shutdown(log, shutdown_type);
+ }
+ return;
+ }
+
+ /* xfs_ail_update_finish() drops the AIL lock */
+ xfs_clear_li_failed(lip);
+ tail_lsn = xfs_ail_delete_one(ailp, lip);
+ xfs_ail_update_finish(ailp, tail_lsn);
+}
+
+int
+xfs_trans_ail_init(
+ xfs_mount_t *mp)
+{
+ struct xfs_ail *ailp;
+
+ ailp = kmem_zalloc(sizeof(struct xfs_ail), KM_MAYFAIL);
+ if (!ailp)
+ return -ENOMEM;
+
+ ailp->ail_log = mp->m_log;
+ INIT_LIST_HEAD(&ailp->ail_head);
+ INIT_LIST_HEAD(&ailp->ail_cursors);
+ spin_lock_init(&ailp->ail_lock);
+ INIT_LIST_HEAD(&ailp->ail_buf_list);
+ init_waitqueue_head(&ailp->ail_empty);
+
+ ailp->ail_task = kthread_run(xfsaild, ailp, "xfsaild/%s",
+ mp->m_super->s_id);
+ if (IS_ERR(ailp->ail_task))
+ goto out_free_ailp;
+
+ mp->m_ail = ailp;
+ return 0;
+
+out_free_ailp:
+ kmem_free(ailp);
+ return -ENOMEM;
+}
+
+void
+xfs_trans_ail_destroy(
+ xfs_mount_t *mp)
+{
+ struct xfs_ail *ailp = mp->m_ail;
+
+ kthread_stop(ailp->ail_task);
+ kmem_free(ailp);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-28 15:22:45 +0000