xfs: port the defer ops capture and continue to resource capture

When log recovery tries to recover a transaction that had log intent
items attached to it, it has to save certain parts of the transaction
state (reservation, dfops chain, inodes with no automatic unlock) so
that it can finish single-stepping the recovered transactions before
finishing the chains.

This is done with the xfs_defer_ops_capture and xfs_defer_ops_continue
functions.  Right now they open-code this functionality, so let's port
this to the formalized resource capture structure that we introduced in
the previous patch.  This enables us to hold up to two inodes and two
buffers during log recovery, the same way we do for regular runtime.

With this patch applied, we'll be ready to support atomic extent swap
which holds two inodes; and logged xattrs which holds one inode and one
xattr leaf buffer.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>

fs/xfs/libxfs/xfs_defer.c

@@ -650,10 +650,11 @@ xfs_defer_move(
  */
 static struct xfs_defer_capture *
 xfs_defer_ops_capture(
-	struct xfs_trans		*tp,
-	struct xfs_inode		*capture_ip)
+	struct xfs_trans		*tp)
 {
 	struct xfs_defer_capture	*dfc;
+	unsigned short			i;
+	int				error;
 
 	if (list_empty(&tp->t_dfops))
 		return NULL;
@@ -677,27 +678,48 @@ xfs_defer_ops_capture(
 	/* Preserve the log reservation size. */
 	dfc->dfc_logres = tp->t_log_res;
 
-	/*
-	 * Grab an extra reference to this inode and attach it to the capture
-	 * structure.
-	 */
-	if (capture_ip) {
-		ihold(VFS_I(capture_ip));
-		dfc->dfc_capture_ip = capture_ip;
+	error = xfs_defer_save_resources(&dfc->dfc_held, tp);
+	if (error) {
+		/*
+		 * Resource capture should never fail, but if it does, we
+		 * still have to shut down the log and release things
+		 * properly.
+		 */
+		xfs_force_shutdown(tp->t_mountp, SHUTDOWN_CORRUPT_INCORE);
 	}
 
+	/*
+	 * Grab extra references to the inodes and buffers because callers are
+	 * expected to release their held references after we commit the
+	 * transaction.
+	 */
+	for (i = 0; i < dfc->dfc_held.dr_inos; i++) {
+		ASSERT(xfs_isilocked(dfc->dfc_held.dr_ip[i], XFS_ILOCK_EXCL));
+		ihold(VFS_I(dfc->dfc_held.dr_ip[i]));
+	}
+
+	for (i = 0; i < dfc->dfc_held.dr_bufs; i++)
+		xfs_buf_hold(dfc->dfc_held.dr_bp[i]);
+
 	return dfc;
 }
 
 /* Release all resources that we used to capture deferred ops. */
 void
-xfs_defer_ops_release(
+xfs_defer_ops_capture_free(
 	struct xfs_mount		*mp,
 	struct xfs_defer_capture	*dfc)
 {
+	unsigned short			i;
+
 	xfs_defer_cancel_list(mp, &dfc->dfc_dfops);
-	if (dfc->dfc_capture_ip)
-		xfs_irele(dfc->dfc_capture_ip);
+
+	for (i = 0; i < dfc->dfc_held.dr_bufs; i++)
+		xfs_buf_relse(dfc->dfc_held.dr_bp[i]);
+
+	for (i = 0; i < dfc->dfc_held.dr_inos; i++)
+		xfs_irele(dfc->dfc_held.dr_ip[i]);
+
 	kmem_free(dfc);
 }
 
@@ -712,24 +734,21 @@ xfs_defer_ops_release(
 int
 xfs_defer_ops_capture_and_commit(
 	struct xfs_trans		*tp,
-	struct xfs_inode		*capture_ip,
 	struct list_head		*capture_list)
 {
 	struct xfs_mount		*mp = tp->t_mountp;
 	struct xfs_defer_capture	*dfc;
 	int				error;
 
-	ASSERT(!capture_ip || xfs_isilocked(capture_ip, XFS_ILOCK_EXCL));
-
 	/* If we don't capture anything, commit transaction and exit. */
-	dfc = xfs_defer_ops_capture(tp, capture_ip);
+	dfc = xfs_defer_ops_capture(tp);
 	if (!dfc)
 		return xfs_trans_commit(tp);
 
 	/* Commit the transaction and add the capture structure to the list. */
 	error = xfs_trans_commit(tp);
 	if (error) {
-		xfs_defer_ops_release(mp, dfc);
+		xfs_defer_ops_capture_free(mp, dfc);
 		return error;
 	}
 
@@ -747,17 +766,19 @@ void
 xfs_defer_ops_continue(
 	struct xfs_defer_capture	*dfc,
 	struct xfs_trans		*tp,
-	struct xfs_inode		**captured_ipp)
+	struct xfs_defer_resources	*dres)
 {
 	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
 	ASSERT(!(tp->t_flags & XFS_TRANS_DIRTY));
 
 	/* Lock and join the captured inode to the new transaction. */
-	if (dfc->dfc_capture_ip) {
-		xfs_ilock(dfc->dfc_capture_ip, XFS_ILOCK_EXCL);
-		xfs_trans_ijoin(tp, dfc->dfc_capture_ip, 0);
-	}
-	*captured_ipp = dfc->dfc_capture_ip;
+	if (dfc->dfc_held.dr_inos == 2)
+		xfs_lock_two_inodes(dfc->dfc_held.dr_ip[0], XFS_ILOCK_EXCL,
+				    dfc->dfc_held.dr_ip[1], XFS_ILOCK_EXCL);
+	else if (dfc->dfc_held.dr_inos == 1)
+		xfs_ilock(dfc->dfc_held.dr_ip[0], XFS_ILOCK_EXCL);
+	xfs_defer_restore_resources(tp, &dfc->dfc_held);
+	memcpy(dres, &dfc->dfc_held, sizeof(struct xfs_defer_resources));
 
 	/* Move captured dfops chain and state to the transaction. */
 	list_splice_init(&dfc->dfc_dfops, &tp->t_dfops);
@@ -765,3 +786,26 @@ xfs_defer_ops_continue(
 
 	kmem_free(dfc);
 }
+
+/* Release the resources captured and continued during recovery. */
+void
+xfs_defer_resources_rele(
+	struct xfs_defer_resources	*dres)
+{
+	unsigned short			i;
+
+	for (i = 0; i < dres->dr_inos; i++) {
+		xfs_iunlock(dres->dr_ip[i], XFS_ILOCK_EXCL);
+		xfs_irele(dres->dr_ip[i]);
+		dres->dr_ip[i] = NULL;
+	}
+
+	for (i = 0; i < dres->dr_bufs; i++) {
+		xfs_buf_relse(dres->dr_bp[i]);
+		dres->dr_bp[i] = NULL;
+	}
+
+	dres->dr_inos = 0;
+	dres->dr_bufs = 0;
+	dres->dr_ordered = 0;
+}

fs/xfs/libxfs/xfs_defer.h

@@ -107,11 +107,7 @@ struct xfs_defer_capture {
 	/* Log reservation saved from the transaction. */
 	unsigned int		dfc_logres;
 
-	/*
-	 * An inode reference that must be maintained to complete the deferred
-	 * work.
-	 */
-	struct xfs_inode	*dfc_capture_ip;
+	struct xfs_defer_resources dfc_held;
 };
 
 /*
@@ -119,9 +115,11 @@ struct xfs_defer_capture {
  * This doesn't normally happen except log recovery.
  */
 int xfs_defer_ops_capture_and_commit(struct xfs_trans *tp,
-		struct xfs_inode *capture_ip, struct list_head *capture_list);
+		struct list_head *capture_list);
 void xfs_defer_ops_continue(struct xfs_defer_capture *d, struct xfs_trans *tp,
-		struct xfs_inode **captured_ipp);
-void xfs_defer_ops_release(struct xfs_mount *mp, struct xfs_defer_capture *d);
+		struct xfs_defer_resources *dres);
+void xfs_defer_ops_capture_free(struct xfs_mount *mp,
+		struct xfs_defer_capture *d);
+void xfs_defer_resources_rele(struct xfs_defer_resources *dres);
 
 #endif /* __XFS_DEFER_H__ */

fs/xfs/xfs_bmap_item.c

@@ -532,7 +532,7 @@ xfs_bui_item_recover(
 	 * Commit transaction, which frees the transaction and saves the inode
 	 * for later replay activities.
 	 */
-	error = xfs_defer_ops_capture_and_commit(tp, ip, capture_list);
+	error = xfs_defer_ops_capture_and_commit(tp, capture_list);
 	if (error)
 		goto err_unlock;
 

fs/xfs/xfs_extfree_item.c

@@ -637,7 +637,7 @@ xfs_efi_item_recover(
 
 	}
 
-	return xfs_defer_ops_capture_and_commit(tp, NULL, capture_list);
+	return xfs_defer_ops_capture_and_commit(tp, capture_list);
 
 abort_error:
 	xfs_trans_cancel(tp);

fs/xfs/xfs_log_recover.c

@@ -2466,11 +2466,11 @@ xlog_finish_defer_ops(
 {
 	struct xfs_defer_capture *dfc, *next;
 	struct xfs_trans	*tp;
-	struct xfs_inode	*ip;
 	int			error = 0;
 
 	list_for_each_entry_safe(dfc, next, capture_list, dfc_list) {
 		struct xfs_trans_res	resv;
+		struct xfs_defer_resources dres;
 
 		/*
 		 * Create a new transaction reservation from the captured
@@ -2494,13 +2494,9 @@ xlog_finish_defer_ops(
 		 * from recovering a single intent item.
 		 */
 		list_del_init(&dfc->dfc_list);
-		xfs_defer_ops_continue(dfc, tp, &ip);
-
+		xfs_defer_ops_continue(dfc, tp, &dres);
 		error = xfs_trans_commit(tp);
-		if (ip) {
-			xfs_iunlock(ip, XFS_ILOCK_EXCL);
-			xfs_irele(ip);
-		}
+		xfs_defer_resources_rele(&dres);
 		if (error)
 			return error;
 	}
@@ -2520,7 +2516,7 @@ xlog_abort_defer_ops(
 
 	list_for_each_entry_safe(dfc, next, capture_list, dfc_list) {
 		list_del_init(&dfc->dfc_list);
-		xfs_defer_ops_release(mp, dfc);
+		xfs_defer_ops_capture_free(mp, dfc);
 	}
 }
 /*

fs/xfs/xfs_refcount_item.c

@@ -557,7 +557,7 @@ xfs_cui_item_recover(
 	}
 
 	xfs_refcount_finish_one_cleanup(tp, rcur, error);
-	return xfs_defer_ops_capture_and_commit(tp, NULL, capture_list);
+	return xfs_defer_ops_capture_and_commit(tp, capture_list);
 
 abort_error:
 	xfs_refcount_finish_one_cleanup(tp, rcur, error);

fs/xfs/xfs_rmap_item.c

@@ -587,7 +587,7 @@ xfs_rui_item_recover(
 	}
 
 	xfs_rmap_finish_one_cleanup(tp, rcur, error);
-	return xfs_defer_ops_capture_and_commit(tp, NULL, capture_list);
+	return xfs_defer_ops_capture_and_commit(tp, capture_list);
 
 abort_error:
 	xfs_rmap_finish_one_cleanup(tp, rcur, error);