Attachment 167864 Details for Bug 207714 – patch applicable to releng/10.3

[patch] patch applicable to releng/10.3

patch.txt (text/plain), 4.98 KB, created by Martin Birgmeier on 2016-03-08 18:10:14 UTC

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Creator: Martin Birgmeier

Created: 2016-03-08 18:10:14 UTC

Size: 4.98 KB

patch

obsolete

>--- ./sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c.ORIG	2016-03-05 14:06:30.367932144 +0100
>+++ ./sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_object.c	2016-03-06 18:08:48.479622033 +0100
>@@ -20,7 +20,7 @@
>  */
> /*
>  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
>- * Copyright (c) 2013, 2014 by Delphix. All rights reserved.
>+ * Copyright (c) 2013, 2015 by Delphix. All rights reserved.
>  * Copyright 2014 HybridCluster. All rights reserved.
>  */
> 
>@@ -50,6 +50,12 @@
> 		 * reasonably sparse (at most 1/4 full).  Look from the
> 		 * beginning once, but after that keep looking from here.
> 		 * If we can't find one, just keep going from here.
>+		 *
>+		 * Note that dmu_traverse depends on the behavior that we use
>+		 * multiple blocks of the dnode object before going back to
>+		 * reuse objects.  Any change to this algorithm should preserve
>+		 * that property or find another solution to the issues described
>+		 * in traverse_visitbp.
> 		 */
> 		if (P2PHASE(object, L2_dnode_count) == 0) {
> 			uint64_t offset = restarted ? object << DNODE_SHIFT : 0;
>--- ./sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c.ORIG	2016-03-05 14:06:30.351992125 +0100
>+++ ./sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c	2016-03-06 18:08:48.516597206 +0100
>@@ -20,7 +20,7 @@
>  */
> /*
>  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
>- * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
>+ * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
>  * Copyright (c) 2015 Chunwei Chen. All rights reserved.
>  */
> 
>@@ -63,6 +63,7 @@
> 	uint64_t td_hole_birth_enabled_txg;
> 	blkptr_cb_t *td_func;
> 	void *td_arg;
>+	boolean_t td_realloc_possible;
> } traverse_data_t;
> 
> static int traverse_dnode(traverse_data_t *td, const dnode_phys_t *dnp,
>@@ -232,18 +233,30 @@
> 
> 	if (bp->blk_birth == 0) {
> 		/*
>-		 * Since this block has a birth time of 0 it must be a
>-		 * hole created before the SPA_FEATURE_HOLE_BIRTH
>-		 * feature was enabled.  If SPA_FEATURE_HOLE_BIRTH
>-		 * was enabled before the min_txg for this traveral we
>-		 * know the hole must have been created before the
>-		 * min_txg for this traveral, so we can skip it. If
>-		 * SPA_FEATURE_HOLE_BIRTH was enabled after the min_txg
>-		 * for this traveral we cannot tell if the hole was
>-		 * created before or after the min_txg for this
>-		 * traversal, so we cannot skip it.
>+		 * Since this block has a birth time of 0 it must be one of two
>+		 * things: a hole created before the SPA_FEATURE_HOLE_BIRTH
>+		 * feature was enabled, or a hole which has always been a hole
>+		 * in an object.  This occurs when an object is created and then
>+		 * a write is performed that leaves part of the file as zeroes.
>+		 * Normally we don't care about this case, but if this object
>+		 * has the same object number as an object that has been
>+		 * destroyed, callers of dmu_traverse may not be able to tell
>+		 * that the object has been recreated.  Thus, we must give them
>+		 * all of the holes with birth == 0 in any objects that may have
>+		 * been recreated. Thus, we cannot skip the block if it is
>+		 * possible the object has been recreated. If it isn't, then if
>+		 * SPA_FEATURE_HOLE_BIRTH was enabled before the min_txg for
>+		 * this traversal we know the hole must have been created before
>+		 * the min_txg for this traversal, so we can skip it. If
>+		 * SPA_FEATURE_HOLE_BIRTH was enabled after the min_txg for this
>+		 * traversal we cannot tell if the hole was created before or
>+		 * after the min_txg for this traversal, so we cannot skip it.
>+		 * Note that the meta-dnode cannot be reallocated, so we needn't
>+		 * worry about that case.
> 		 */
>-		if (td->td_hole_birth_enabled_txg < td->td_min_txg)
>+		if ((!td->td_realloc_possible ||
>+		    zb->zb_object == DMU_META_DNODE_OBJECT) &&
>+		    td->td_hole_birth_enabled_txg <= td->td_min_txg)
> 			return (0);
> 	} else if (bp->blk_birth <= td->td_min_txg) {
> 		return (0);
>@@ -338,6 +351,15 @@
> 		objset_phys_t *osp = buf->b_data;
> 		prefetch_dnode_metadata(td, &osp->os_meta_dnode, zb->zb_objset,
> 		    DMU_META_DNODE_OBJECT);
>+		/*
>+		 * See the block comment above for the goal of this variable.
>+		 * If the maxblkid of the meta-dnode is 0, then we know that
>+		 * we've never had more than DNODES_PER_BLOCK objects in the
>+		 * dataset, which means we can't have reused any object ids.
>+		 */
>+		if (osp->os_meta_dnode.dn_maxblkid == 0)
>+			td->td_realloc_possible = B_FALSE;
>+
> 		if (arc_buf_size(buf) >= sizeof (objset_phys_t)) {
> 			prefetch_dnode_metadata(td, &osp->os_groupused_dnode,
> 			    zb->zb_objset, DMU_GROUPUSED_OBJECT);
>@@ -544,12 +566,13 @@
> 	td.td_pfd = &pd;
> 	td.td_flags = flags;
> 	td.td_paused = B_FALSE;
>+	td.td_realloc_possible = (txg_start == 0 ? B_FALSE : B_TRUE);
> 
> 	if (spa_feature_is_active(spa, SPA_FEATURE_HOLE_BIRTH)) {
> 		VERIFY(spa_feature_enabled_txg(spa,
> 		    SPA_FEATURE_HOLE_BIRTH, &td.td_hole_birth_enabled_txg));
> 	} else {
>-		td.td_hole_birth_enabled_txg = 0;
>+		td.td_hole_birth_enabled_txg = UINT64_MAX;
> 	}
> 
> 	pd.pd_flags = flags;

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