xfs: create refcount update intent log items

Create refcount update intent/done log items to record redo
information in the log.  Because we need to roll transactions between
updating the bmbt mapping and updating the reverse mapping, we also
have to track the status of the metadata updates that will be recorded
in the post-roll transactions, just in case we crash before committing
the final transaction.  This mechanism enables log recovery to finish
what was already started.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 383 insertions, 0 deletions

diff --git a/fs/xfs/xfs_refcount_item.c b/fs/xfs/xfs_refcount_item.c
new file mode 100644
index 000000000000..f9ad05529eba
--- /dev/null
+++ b/fs/xfs/xfs_refcount_item.c
@@ -0,0 +1,383 @@
+/*
+ * Copyright (C) 2016 Oracle.  All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * 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.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+#include "xfs.h"
+#include "xfs_fs.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_buf_item.h"
+#include "xfs_refcount_item.h"
+#include "xfs_log.h"
+
+
+kmem_zone_t	*xfs_cui_zone;
+kmem_zone_t	*xfs_cud_zone;
+
+static inline struct xfs_cui_log_item *CUI_ITEM(struct xfs_log_item *lip)
+{
+	return container_of(lip, struct xfs_cui_log_item, cui_item);
+}
+
+void
+xfs_cui_item_free(
+	struct xfs_cui_log_item	*cuip)
+{
+	if (cuip->cui_format.cui_nextents > XFS_CUI_MAX_FAST_EXTENTS)
+		kmem_free(cuip);
+	else
+		kmem_zone_free(xfs_cui_zone, cuip);
+}
+
+STATIC void
+xfs_cui_item_size(
+	struct xfs_log_item	*lip,
+	int			*nvecs,
+	int			*nbytes)
+{
+	struct xfs_cui_log_item	*cuip = CUI_ITEM(lip);
+
+	*nvecs += 1;
+	*nbytes += xfs_cui_log_format_sizeof(cuip->cui_format.cui_nextents);
+}
+
+/*
+ * This is called to fill in the vector of log iovecs for the
+ * given cui log item. We use only 1 iovec, and we point that
+ * at the cui_log_format structure embedded in the cui item.
+ * It is at this point that we assert that all of the extent
+ * slots in the cui item have been filled.
+ */
+STATIC void
+xfs_cui_item_format(
+	struct xfs_log_item	*lip,
+	struct xfs_log_vec	*lv)
+{
+	struct xfs_cui_log_item	*cuip = CUI_ITEM(lip);
+	struct xfs_log_iovec	*vecp = NULL;
+
+	ASSERT(atomic_read(&cuip->cui_next_extent) ==
+			cuip->cui_format.cui_nextents);
+
+	cuip->cui_format.cui_type = XFS_LI_CUI;
+	cuip->cui_format.cui_size = 1;
+
+	xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_CUI_FORMAT, &cuip->cui_format,
+			xfs_cui_log_format_sizeof(cuip->cui_format.cui_nextents));
+}
+
+/*
+ * Pinning has no meaning for an cui item, so just return.
+ */
+STATIC void
+xfs_cui_item_pin(
+	struct xfs_log_item	*lip)
+{
+}
+
+/*
+ * The unpin operation is the last place an CUI is manipulated in the log. It is
+ * either inserted in the AIL or aborted in the event of a log I/O error. In
+ * either case, the CUI transaction has been successfully committed to make it
+ * this far. Therefore, we expect whoever committed the CUI to either construct
+ * and commit the CUD or drop the CUD's reference in the event of error. Simply
+ * drop the log's CUI reference now that the log is done with it.
+ */
+STATIC void
+xfs_cui_item_unpin(
+	struct xfs_log_item	*lip,
+	int			remove)
+{
+	struct xfs_cui_log_item	*cuip = CUI_ITEM(lip);
+
+	xfs_cui_release(cuip);
+}
+
+/*
+ * CUI items have no locking or pushing.  However, since CUIs are pulled from
+ * the AIL when their corresponding CUDs are committed to disk, their situation
+ * is very similar to being pinned.  Return XFS_ITEM_PINNED so that the caller
+ * will eventually flush the log.  This should help in getting the CUI out of
+ * the AIL.
+ */
+STATIC uint
+xfs_cui_item_push(
+	struct xfs_log_item	*lip,
+	struct list_head	*buffer_list)
+{
+	return XFS_ITEM_PINNED;
+}
+
+/*
+ * The CUI has been either committed or aborted if the transaction has been
+ * cancelled. If the transaction was cancelled, an CUD isn't going to be
+ * constructed and thus we free the CUI here directly.
+ */
+STATIC void
+xfs_cui_item_unlock(
+	struct xfs_log_item	*lip)
+{
+	if (lip->li_flags & XFS_LI_ABORTED)
+		xfs_cui_item_free(CUI_ITEM(lip));
+}
+
+/*
+ * The CUI is logged only once and cannot be moved in the log, so simply return
+ * the lsn at which it's been logged.
+ */
+STATIC xfs_lsn_t
+xfs_cui_item_committed(
+	struct xfs_log_item	*lip,
+	xfs_lsn_t		lsn)
+{
+	return lsn;
+}
+
+/*
+ * The CUI dependency tracking op doesn't do squat.  It can't because
+ * it doesn't know where the free extent is coming from.  The dependency
+ * tracking has to be handled by the "enclosing" metadata object.  For
+ * example, for inodes, the inode is locked throughout the extent freeing
+ * so the dependency should be recorded there.
+ */
+STATIC void
+xfs_cui_item_committing(
+	struct xfs_log_item	*lip,
+	xfs_lsn_t		lsn)
+{
+}
+
+/*
+ * This is the ops vector shared by all cui log items.
+ */
+static const struct xfs_item_ops xfs_cui_item_ops = {
+	.iop_size	= xfs_cui_item_size,
+	.iop_format	= xfs_cui_item_format,
+	.iop_pin	= xfs_cui_item_pin,
+	.iop_unpin	= xfs_cui_item_unpin,
+	.iop_unlock	= xfs_cui_item_unlock,
+	.iop_committed	= xfs_cui_item_committed,
+	.iop_push	= xfs_cui_item_push,
+	.iop_committing = xfs_cui_item_committing,
+};
+
+/*
+ * Allocate and initialize an cui item with the given number of extents.
+ */
+struct xfs_cui_log_item *
+xfs_cui_init(
+	struct xfs_mount		*mp,
+	uint				nextents)
+
+{
+	struct xfs_cui_log_item		*cuip;
+
+	ASSERT(nextents > 0);
+	if (nextents > XFS_CUI_MAX_FAST_EXTENTS)
+		cuip = kmem_zalloc(xfs_cui_log_item_sizeof(nextents),
+				KM_SLEEP);
+	else
+		cuip = kmem_zone_zalloc(xfs_cui_zone, KM_SLEEP);
+
+	xfs_log_item_init(mp, &cuip->cui_item, XFS_LI_CUI, &xfs_cui_item_ops);
+	cuip->cui_format.cui_nextents = nextents;
+	cuip->cui_format.cui_id = (uintptr_t)(void *)cuip;
+	atomic_set(&cuip->cui_next_extent, 0);
+	atomic_set(&cuip->cui_refcount, 2);
+
+	return cuip;
+}
+
+/*
+ * Freeing the CUI requires that we remove it from the AIL if it has already
+ * been placed there. However, the CUI may not yet have been placed in the AIL
+ * when called by xfs_cui_release() from CUD processing due to the ordering of
+ * committed vs unpin operations in bulk insert operations. Hence the reference
+ * count to ensure only the last caller frees the CUI.
+ */
+void
+xfs_cui_release(
+	struct xfs_cui_log_item	*cuip)
+{
+	if (atomic_dec_and_test(&cuip->cui_refcount)) {
+		xfs_trans_ail_remove(&cuip->cui_item, SHUTDOWN_LOG_IO_ERROR);
+		xfs_cui_item_free(cuip);
+	}
+}
+
+static inline struct xfs_cud_log_item *CUD_ITEM(struct xfs_log_item *lip)
+{
+	return container_of(lip, struct xfs_cud_log_item, cud_item);
+}
+
+STATIC void
+xfs_cud_item_size(
+	struct xfs_log_item	*lip,
+	int			*nvecs,
+	int			*nbytes)
+{
+	*nvecs += 1;
+	*nbytes += sizeof(struct xfs_cud_log_format);
+}
+
+/*
+ * This is called to fill in the vector of log iovecs for the
+ * given cud log item. We use only 1 iovec, and we point that
+ * at the cud_log_format structure embedded in the cud item.
+ * It is at this point that we assert that all of the extent
+ * slots in the cud item have been filled.
+ */
+STATIC void
+xfs_cud_item_format(
+	struct xfs_log_item	*lip,
+	struct xfs_log_vec	*lv)
+{
+	struct xfs_cud_log_item	*cudp = CUD_ITEM(lip);
+	struct xfs_log_iovec	*vecp = NULL;
+
+	cudp->cud_format.cud_type = XFS_LI_CUD;
+	cudp->cud_format.cud_size = 1;
+
+	xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_CUD_FORMAT, &cudp->cud_format,
+			sizeof(struct xfs_cud_log_format));
+}
+
+/*
+ * Pinning has no meaning for an cud item, so just return.
+ */
+STATIC void
+xfs_cud_item_pin(
+	struct xfs_log_item	*lip)
+{
+}
+
+/*
+ * Since pinning has no meaning for an cud item, unpinning does
+ * not either.
+ */
+STATIC void
+xfs_cud_item_unpin(
+	struct xfs_log_item	*lip,
+	int			remove)
+{
+}
+
+/*
+ * There isn't much you can do to push on an cud item.  It is simply stuck
+ * waiting for the log to be flushed to disk.
+ */
+STATIC uint
+xfs_cud_item_push(
+	struct xfs_log_item	*lip,
+	struct list_head	*buffer_list)
+{
+	return XFS_ITEM_PINNED;
+}
+
+/*
+ * The CUD is either committed or aborted if the transaction is cancelled. If
+ * the transaction is cancelled, drop our reference to the CUI and free the
+ * CUD.
+ */
+STATIC void
+xfs_cud_item_unlock(
+	struct xfs_log_item	*lip)
+{
+	struct xfs_cud_log_item	*cudp = CUD_ITEM(lip);
+
+	if (lip->li_flags & XFS_LI_ABORTED) {
+		xfs_cui_release(cudp->cud_cuip);
+		kmem_zone_free(xfs_cud_zone, cudp);
+	}
+}
+
+/*
+ * When the cud item is committed to disk, all we need to do is delete our
+ * reference to our partner cui item and then free ourselves. Since we're
+ * freeing ourselves we must return -1 to keep the transaction code from
+ * further referencing this item.
+ */
+STATIC xfs_lsn_t
+xfs_cud_item_committed(
+	struct xfs_log_item	*lip,
+	xfs_lsn_t		lsn)
+{
+	struct xfs_cud_log_item	*cudp = CUD_ITEM(lip);
+
+	/*
+	 * Drop the CUI reference regardless of whether the CUD has been
+	 * aborted. Once the CUD transaction is constructed, it is the sole
+	 * responsibility of the CUD to release the CUI (even if the CUI is
+	 * aborted due to log I/O error).
+	 */
+	xfs_cui_release(cudp->cud_cuip);
+	kmem_zone_free(xfs_cud_zone, cudp);
+
+	return (xfs_lsn_t)-1;
+}
+
+/*
+ * The CUD dependency tracking op doesn't do squat.  It can't because
+ * it doesn't know where the free extent is coming from.  The dependency
+ * tracking has to be handled by the "enclosing" metadata object.  For
+ * example, for inodes, the inode is locked throughout the extent freeing
+ * so the dependency should be recorded there.
+ */
+STATIC void
+xfs_cud_item_committing(
+	struct xfs_log_item	*lip,
+	xfs_lsn_t		lsn)
+{
+}
+
+/*
+ * This is the ops vector shared by all cud log items.
+ */
+static const struct xfs_item_ops xfs_cud_item_ops = {
+	.iop_size	= xfs_cud_item_size,
+	.iop_format	= xfs_cud_item_format,
+	.iop_pin	= xfs_cud_item_pin,
+	.iop_unpin	= xfs_cud_item_unpin,
+	.iop_unlock	= xfs_cud_item_unlock,
+	.iop_committed	= xfs_cud_item_committed,
+	.iop_push	= xfs_cud_item_push,
+	.iop_committing = xfs_cud_item_committing,
+};
+
+/*
+ * Allocate and initialize an cud item with the given number of extents.
+ */
+struct xfs_cud_log_item *
+xfs_cud_init(
+	struct xfs_mount		*mp,
+	struct xfs_cui_log_item		*cuip)
+
+{
+	struct xfs_cud_log_item	*cudp;
+
+	cudp = kmem_zone_zalloc(xfs_cud_zone, KM_SLEEP);
+	xfs_log_item_init(mp, &cudp->cud_item, XFS_LI_CUD, &xfs_cud_item_ops);
+	cudp->cud_cuip = cuip;
+	cudp->cud_format.cud_cui_id = cuip->cui_format.cui_id;
+
+	return cudp;
+}