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* [PATCH] btrfs-progs: check: skip shared node or leaf check for low_memory mode
@ 2016-08-19  9:59 Wang Xiaoguang
  2016-08-24 12:44 ` David Sterba
  0 siblings, 1 reply; 8+ messages in thread
From: Wang Xiaoguang @ 2016-08-19  9:59 UTC (permalink / raw)
  To: linux-btrfs; +Cc: dsterba

The basic idea is simple. Assume a middle tree node A is shared and
its referenceing fs/file tree root ids are 5, 258 and 260, then we
only check node A in the tree who has the smallest root id. That means
in this case, when checking root tree(5), we check inode A, for root
tree 258 and 260, we can just skip it.

Notice even with this patch, we still may visit a shared node or leaf
multiple times. This happens when a inode metadata occupies multiple
leaves.

                 leaf_A     leaf_B
When checking inode item in leaf_A, assume inode[512] have file extents
in leaf_B, and leaf_B is shared. In the case, for inode[512], we must
visit leaf_B to have inode item check. After finishing inode[512] check,
here we walk down tree root to leaf_B to check whether node or leaf
is shared, if some node or leaf is shared, we can just skip it and below
nodes or leaf's check.

I also fill a disk partition with linux source codes and create 3 snapshots
in it. Before this patch, it averagely took 46s to finish one btrfsck
execution, with this patch, it averagely took 15s.

Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
---
 cmds-check.c | 353 +++++++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 282 insertions(+), 71 deletions(-)

diff --git a/cmds-check.c b/cmds-check.c
index ae37aed..658fa3d 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -105,6 +105,24 @@ struct data_backref {
 	u32 found_ref;
 };
 
+#define ROOT_DIR_ERROR		(1<<1)	/* bad root_dir */
+#define DIR_ITEM_MISSING	(1<<2)	/* DIR_ITEM not found */
+#define DIR_ITEM_MISMATCH	(1<<3)	/* DIR_ITEM found but not match */
+#define INODE_REF_MISSING	(1<<4)	/* INODE_REF/INODE_EXTREF not found */
+#define INODE_ITEM_MISSING	(1<<5)	/* INODE_ITEM not found */
+#define INODE_ITEM_MISMATCH	(1<<6)	/* INODE_ITEM found but not match */
+#define FILE_EXTENT_ERROR	(1<<7)	/* bad file extent */
+#define ODD_CSUM_ITEM		(1<<8)	/* CSUM_ITEM ERROR */
+#define CSUM_ITEM_MISSING	(1<<9)	/* CSUM_ITEM not found */
+#define LINK_COUNT_ERROR	(1<<10)	/* INODE_ITEM nlink count error */
+#define NBYTES_ERROR		(1<<11)	/* INODE_ITEM nbytes count error */
+#define ISIZE_ERROR		(1<<12)	/* INODE_ITEM size count error */
+#define ORPHAN_ITEM		(1<<13) /* INODE_ITEM no reference */
+#define NO_INODE_ITEM		(1<<14) /* no inode_item */
+#define LAST_ITEM		(1<<15)	/* Complete this tree traversal */
+#define ROOT_REF_MISSING	(1<<16)	/* ROOT_REF not found */
+#define ROOT_REF_MISMATCH	(1<<17)	/* ROOT_REF found but not match */
+
 static inline struct data_backref* to_data_backref(struct extent_backref *back)
 {
 	return container_of(back, struct data_backref, node);
@@ -1975,8 +1993,70 @@ static int check_child_node(struct btrfs_root *root,
 struct node_refs {
 	u64 bytenr[BTRFS_MAX_LEVEL];
 	u64 refs[BTRFS_MAX_LEVEL];
+	int need_check[BTRFS_MAX_LEVEL];
 };
 
+/*
+ * for a tree node or leaf, if it's shared, indeed we don't need to iterate it
+ * in every fs or file tree check. Here we find its all root ids, and only check
+ * it in the fs or file tree which has the smallest root id.
+ */
+static int need_check(struct btrfs_root *root, struct ulist *roots)
+{
+	struct rb_node *node;
+	struct ulist_node *u;
+
+	if (roots->nnodes == 1)
+		return 1;
+
+	node = rb_first(&roots->root);
+	u = rb_entry(node, struct ulist_node, rb_node);
+	/*
+	 * current root id is not smallest, we skip it and let it be checked
+	 * in the fs or file tree who hash the smallest root id.
+	 */
+	if (root->objectid != u->val)
+		return 0;
+
+	return 1;
+}
+
+/*
+ * for a tree node or leaf, we record its reference count, so later if we still
+ * process this node or leaf, don't need to compute its reference count again.
+ */
+static int update_nodes_refs(struct btrfs_root *root, u64 bytenr,
+			     struct node_refs *nrefs, u64 level)
+{
+	int check, ret;
+	u64 refs;
+	struct ulist *roots;
+
+	if (nrefs->bytenr[level] != bytenr) {
+		ret = btrfs_lookup_extent_info(NULL, root, bytenr,
+				       level, 1, &refs, NULL);
+		if (ret < 0)
+			return ret;
+
+		nrefs->bytenr[level] = bytenr;
+		nrefs->refs[level] = refs;
+		if (refs > 1) {
+			ret = btrfs_find_all_roots(NULL, root->fs_info, bytenr,
+						   0, &roots);
+			if (ret)
+				return -EIO;
+
+			check = need_check(root, roots);
+			ulist_free(roots);
+			nrefs->need_check[level] = check;
+		} else {
+			nrefs->need_check[level] = 1;
+		}
+	}
+
+	return 0;
+}
+
 static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
 			  struct walk_control *wc, int *level,
 			  struct node_refs *nrefs)
@@ -2001,6 +2081,7 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
 				       path->nodes[*level]->start,
 				       *level, 1, &refs, NULL);
 		if (ret < 0) {
+			fprintf(stderr, "zhaoyan\n");
 			err = ret;
 			goto out;
 		}
@@ -2106,6 +2187,164 @@ out:
 	return err;
 }
 
+static int check_inode_item(struct btrfs_root *root, struct btrfs_path *path,
+			    unsigned int ext_ref);
+
+static int walk_down_tree_v2(struct btrfs_root *root, struct btrfs_path *path,
+			     int *level, struct node_refs *nrefs, int ext_ref)
+{
+	enum btrfs_tree_block_status status;
+	u64 bytenr, cur_bytenr;
+	u64 ptr_gen;
+	struct extent_buffer *next;
+	struct extent_buffer *cur;
+	struct btrfs_key key;
+	u32 blocksize;
+	u32 nritems;
+	int i, ret, err = 0;
+	int root_level = btrfs_header_level(root->node);
+
+	WARN_ON(*level < 0);
+	WARN_ON(*level >= BTRFS_MAX_LEVEL);
+
+	ret = update_nodes_refs(root, path->nodes[*level]->start,
+				nrefs, *level);
+	if (ret < 0) {
+		err = ret;
+		goto out;
+	}
+
+	while (*level >= 0) {
+		WARN_ON(*level < 0);
+		WARN_ON(*level >= BTRFS_MAX_LEVEL);
+		cur = path->nodes[*level];
+
+		if (btrfs_header_level(cur) != *level)
+			WARN_ON(1);
+
+		if (path->slots[*level] >= btrfs_header_nritems(cur))
+			break;
+		if (*level == 0) {
+			/* check all inode items in this leaf */
+			cur_bytenr = path->nodes[0]->start;
+
+			/* skip to first inode item in this leaf */
+			nritems = btrfs_header_nritems(cur);
+			for (i = 0; i < nritems; i++) {
+				btrfs_item_key_to_cpu(cur, &key, i);
+				if (key.type == BTRFS_INODE_ITEM_KEY)
+					break;
+			}
+			if (i == nritems) {
+				path->slots[0] = nritems;
+				break;
+			}
+			path->slots[0] = i;
+
+again:
+			ret = check_inode_item(root, path, ext_ref);
+			if (ret == -EIO) {
+				err = ret;
+				break;
+			}
+			if (ret & LAST_ITEM) {
+				err = ret & ~LAST_ITEM;
+				break;
+			}
+
+			/* still have inode items in thie leaf */
+			if (path->nodes[0]->start == cur_bytenr)
+				goto again;
+
+			/*
+			 * we have switched to another leaf, above nodes may
+			 * have changed, here walk down the path, if a node
+			 * or leaf is shared, check whether we can skip this
+			 * node or leaf.
+			 */
+			for (i = root_level; i >= 0; i--) {
+				if (path->nodes[i]->start == nrefs->bytenr[i])
+					continue;
+
+				ret = update_nodes_refs(root,
+						path->nodes[i]->start,
+						nrefs, i);
+				if (ret) {
+					err = ret;
+					goto out;
+				}
+				if (!nrefs->need_check[i]) {
+					*level += 1;
+					break;
+				}
+			}
+
+			for (i = 0; i < *level; i++) {
+				free_extent_buffer(path->nodes[i]);
+				path->nodes[i] = NULL;
+			}
+			break;
+		}
+		bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
+		ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
+		blocksize = root->nodesize;
+
+		ret = update_nodes_refs(root, bytenr, nrefs, *level - 1);
+		if (ret) {
+			err = ret;
+			goto out;
+		}
+		if (!nrefs->need_check[*level - 1]) {
+			path->slots[*level]++;
+			continue;
+		}
+
+		next = btrfs_find_tree_block(root, bytenr, blocksize);
+		if (!next || !btrfs_buffer_uptodate(next, ptr_gen)) {
+			free_extent_buffer(next);
+			reada_walk_down(root, cur, path->slots[*level]);
+			next = read_tree_block(root, bytenr, blocksize,
+					       ptr_gen);
+			if (!extent_buffer_uptodate(next)) {
+				struct btrfs_key node_key;
+
+				btrfs_node_key_to_cpu(path->nodes[*level],
+						      &node_key,
+						      path->slots[*level]);
+				btrfs_add_corrupt_extent_record(root->fs_info,
+						&node_key,
+						path->nodes[*level]->start,
+						root->nodesize, *level);
+				err = -EIO;
+				goto out;
+			}
+		}
+
+		ret = check_child_node(root, cur, path->slots[*level], next);
+		if (ret) {
+			err = ret;
+			goto out;
+		}
+
+		if (btrfs_is_leaf(next))
+			status = btrfs_check_leaf(root, NULL, next);
+		else
+			status = btrfs_check_node(root, NULL, next);
+		if (status != BTRFS_TREE_BLOCK_CLEAN) {
+			free_extent_buffer(next);
+			err = -EIO;
+			goto out;
+		}
+
+		*level = *level - 1;
+		free_extent_buffer(path->nodes[*level]);
+		path->nodes[*level] = next;
+		path->slots[*level] = 0;
+	}
+out:
+	return err & ~LAST_ITEM;
+}
+
 static int walk_up_tree(struct btrfs_root *root, struct btrfs_path *path,
 			struct walk_control *wc, int *level)
 {
@@ -2130,6 +2369,27 @@ static int walk_up_tree(struct btrfs_root *root, struct btrfs_path *path,
 	return 1;
 }
 
+static int walk_up_tree_v2(struct btrfs_root *root, struct btrfs_path *path,
+			   int *level)
+{
+	int i;
+	struct extent_buffer *leaf;
+
+	for (i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
+		leaf = path->nodes[i];
+		if (path->slots[i] + 1 < btrfs_header_nritems(leaf)) {
+			path->slots[i]++;
+			*level = i;
+			return 0;
+		} else {
+			free_extent_buffer(path->nodes[*level]);
+			path->nodes[*level] = NULL;
+			*level = i + 1;
+		}
+	}
+	return 1;
+}
+
 static int check_root_dir(struct inode_record *rec)
 {
 	struct inode_backref *backref;
@@ -3904,24 +4164,6 @@ out:
 	return err;
 }
 
-#define ROOT_DIR_ERROR		(1<<1)	/* bad root_dir */
-#define DIR_ITEM_MISSING	(1<<2)	/* DIR_ITEM not found */
-#define DIR_ITEM_MISMATCH	(1<<3)	/* DIR_ITEM found but not match */
-#define INODE_REF_MISSING	(1<<4)	/* INODE_REF/INODE_EXTREF not found */
-#define INODE_ITEM_MISSING	(1<<5)	/* INODE_ITEM not found */
-#define INODE_ITEM_MISMATCH	(1<<6)	/* INODE_ITEM found but not match */
-#define FILE_EXTENT_ERROR	(1<<7)	/* bad file extent */
-#define ODD_CSUM_ITEM		(1<<8)	/* CSUM_ITEM ERROR */
-#define CSUM_ITEM_MISSING	(1<<9)	/* CSUM_ITEM not found */
-#define LINK_COUNT_ERROR	(1<<10)	/* INODE_ITEM nlink count error */
-#define NBYTES_ERROR		(1<<11)	/* INODE_ITEM nbytes count error */
-#define ISIZE_ERROR		(1<<12)	/* INODE_ITEM size count error */
-#define ORPHAN_ITEM		(1<<13) /* INODE_ITEM no reference */
-#define NO_INODE_ITEM		(1<<14) /* no inode_item */
-#define LAST_ITEM		(1<<15)	/* Complete this tree traversal */
-#define ROOT_REF_MISSING	(1<<16)	/* ROOT_REF not found */
-#define ROOT_REF_MISMATCH	(1<<17)	/* ROOT_REF found but not match */
-
 /*
  * Find DIR_ITEM/DIR_INDEX for the given key and check it with the specified
  * INODE_REF/INODE_EXTREF match.
@@ -4729,8 +4971,8 @@ out:
 		if (nlink != refs) {
 			err |= LINK_COUNT_ERROR;
 			error(
-			"root %llu INODE[%llu] nlink(%llu) not equal to inode_refs(%llu)",
-			root->objectid, inode_id, nlink, refs);
+			"root %llu INODE[%llu] nlink(%llu) not equal to inode_refs(%llu) %d",
+			root->objectid, inode_id, nlink, refs, err);
 		} else if (!nlink) {
 			err |= ORPHAN_ITEM;
 		}
@@ -4748,6 +4990,7 @@ out:
 			"root %llu INODE[%llu] nbytes(%llu) not equal to extent_size(%llu)",
 			root->objectid, inode_id, nbytes, extent_size);
 		}
+		fflush(stderr);
 	}
 
 	return err;
@@ -4764,68 +5007,36 @@ out:
 static int check_fs_root_v2(struct btrfs_root *root, unsigned int ext_ref)
 {
 	struct btrfs_path *path;
-	struct btrfs_key key;
-	u64 inode_id;
-	int ret, err = 0;
+	struct node_refs nrefs;
+	int wret, ret = 0;
+	int level;
 
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
 
-	key.objectid = 0;
-	key.type = 0;
-	key.offset = 0;
-
-	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-	if (ret < 0) {
-		err = ret;
-		goto out;
-	}
+	memset(&nrefs, 0, sizeof(nrefs));
+	level = btrfs_header_level(root->node);
+	path->nodes[level] = root->node;
+	path->slots[level] = 0;
+	extent_buffer_get(root->node);
 
 	while (1) {
-		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
-
-		/*
-		 * All check must start with inode item, skip if not
-		 */
-		if (btrfs_key_type(&key) == BTRFS_INODE_ITEM_KEY) {
-			ret = check_inode_item(root, path, ext_ref);
-			if (ret == -EIO)
-				goto out;
-			err |= ret;
-			if (err & LAST_ITEM)
-				goto out;
-		} else {
-			error(
-			"root %llu ITEM[%llu %u %llu] isn't INODE_ITEM, skip to next inode",
-			root->objectid, key.objectid, key.type, key.offset);
-			goto skip;
-		}
-
-		continue;
-
-skip:
-		err |= NO_INODE_ITEM;
-		inode_id = key.objectid;
+		wret = walk_down_tree_v2(root, path, &level, &nrefs, ext_ref);
+		if (wret < 0)
+			ret = wret;
+		if (wret != 0)
+			break;
 
-		/* skip to next inode */
-		do {
-			ret = btrfs_next_item(root, path);
-			if (ret > 0) {
-				goto out;
-			} else if (ret < 0) {
-				err = ret;
-				goto out;
-			}
-			btrfs_item_key_to_cpu(path->nodes[0], &key,
-					      path->slots[0]);
-		} while (inode_id == key.objectid);
+		wret = walk_up_tree_v2(root, path, &level);
+		if (wret < 0)
+			ret = wret;
+		if (wret != 0)
+			break;
 	}
 
-out:
-	err &= ~LAST_ITEM;
 	btrfs_free_path(path);
-	return err;
+	return ret;
 }
 
 /*
-- 
2.9.0




^ permalink raw reply related	[flat|nested] 8+ messages in thread

* Re: [PATCH] btrfs-progs: check: skip shared node or leaf check for low_memory mode
  2016-08-19  9:59 [PATCH] btrfs-progs: check: skip shared node or leaf check for low_memory mode Wang Xiaoguang
@ 2016-08-24 12:44 ` David Sterba
  2016-08-25  5:30   ` Wang Xiaoguang
  0 siblings, 1 reply; 8+ messages in thread
From: David Sterba @ 2016-08-24 12:44 UTC (permalink / raw)
  To: Wang Xiaoguang; +Cc: linux-btrfs, dsterba

On Fri, Aug 19, 2016 at 05:59:46PM +0800, Wang Xiaoguang wrote:
> The basic idea is simple. Assume a middle tree node A is shared and
> its referenceing fs/file tree root ids are 5, 258 and 260, then we
> only check node A in the tree who has the smallest root id. That means
> in this case, when checking root tree(5), we check inode A, for root
> tree 258 and 260, we can just skip it.
> 
> Notice even with this patch, we still may visit a shared node or leaf
> multiple times. This happens when a inode metadata occupies multiple
> leaves.
> 
>                  leaf_A     leaf_B
> When checking inode item in leaf_A, assume inode[512] have file extents
> in leaf_B, and leaf_B is shared. In the case, for inode[512], we must
> visit leaf_B to have inode item check. After finishing inode[512] check,
> here we walk down tree root to leaf_B to check whether node or leaf
> is shared, if some node or leaf is shared, we can just skip it and below
> nodes or leaf's check.
> 
> I also fill a disk partition with linux source codes and create 3 snapshots
> in it. Before this patch, it averagely took 46s to finish one btrfsck
> execution, with this patch, it averagely took 15s.
> 
> Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>

Can you please refresh the patch on top of current devel branch? I get
too many conflicts to resolve.

> @@ -2001,6 +2081,7 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
>  				       path->nodes[*level]->start,
>  				       *level, 1, &refs, NULL);
>  		if (ret < 0) {
> +			fprintf(stderr, "zhaoyan\n");

Probably a debugging leftover

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH] btrfs-progs: check: skip shared node or leaf check for low_memory mode
  2016-08-24 12:44 ` David Sterba
@ 2016-08-25  5:30   ` Wang Xiaoguang
  2016-08-29 15:20     ` David Sterba
  0 siblings, 1 reply; 8+ messages in thread
From: Wang Xiaoguang @ 2016-08-25  5:30 UTC (permalink / raw)
  To: dsterba, linux-btrfs

Hi,

On 08/24/2016 08:44 PM, David Sterba wrote:
> On Fri, Aug 19, 2016 at 05:59:46PM +0800, Wang Xiaoguang wrote:
>> The basic idea is simple. Assume a middle tree node A is shared and
>> its referenceing fs/file tree root ids are 5, 258 and 260, then we
>> only check node A in the tree who has the smallest root id. That means
>> in this case, when checking root tree(5), we check inode A, for root
>> tree 258 and 260, we can just skip it.
>>
>> Notice even with this patch, we still may visit a shared node or leaf
>> multiple times. This happens when a inode metadata occupies multiple
>> leaves.
>>
>>                   leaf_A     leaf_B
>> When checking inode item in leaf_A, assume inode[512] have file extents
>> in leaf_B, and leaf_B is shared. In the case, for inode[512], we must
>> visit leaf_B to have inode item check. After finishing inode[512] check,
>> here we walk down tree root to leaf_B to check whether node or leaf
>> is shared, if some node or leaf is shared, we can just skip it and below
>> nodes or leaf's check.
>>
>> I also fill a disk partition with linux source codes and create 3 snapshots
>> in it. Before this patch, it averagely took 46s to finish one btrfsck
>> execution, with this patch, it averagely took 15s.
>>
>> Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
> Can you please refresh the patch on top of current devel branch? I get
> too many conflicts to resolve.
This patch is to improve low memory mode fs/file tree check, but it seems
Lu Fengqi's low memory fs/file tree check patches are not merged into your
devel branch :)

>
>> @@ -2001,6 +2081,7 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
>>   				       path->nodes[*level]->start,
>>   				       *level, 1, &refs, NULL);
>>   		if (ret < 0) {
>> +			fprintf(stderr, "zhaoyan\n");
> Probably a debugging leftover
:)  I'll remove it.

Regards,
Xiaoguang Wang

>
>




^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH] btrfs-progs: check: skip shared node or leaf check for low_memory mode
  2016-08-25  5:30   ` Wang Xiaoguang
@ 2016-08-29 15:20     ` David Sterba
  2016-08-30  1:50       ` Qu Wenruo
  0 siblings, 1 reply; 8+ messages in thread
From: David Sterba @ 2016-08-29 15:20 UTC (permalink / raw)
  To: Wang Xiaoguang; +Cc: dsterba, linux-btrfs

On Thu, Aug 25, 2016 at 01:30:09PM +0800, Wang Xiaoguang wrote:
> Hi,
> 
> On 08/24/2016 08:44 PM, David Sterba wrote:
> > On Fri, Aug 19, 2016 at 05:59:46PM +0800, Wang Xiaoguang wrote:
> >> The basic idea is simple. Assume a middle tree node A is shared and
> >> its referenceing fs/file tree root ids are 5, 258 and 260, then we
> >> only check node A in the tree who has the smallest root id. That means
> >> in this case, when checking root tree(5), we check inode A, for root
> >> tree 258 and 260, we can just skip it.
> >>
> >> Notice even with this patch, we still may visit a shared node or leaf
> >> multiple times. This happens when a inode metadata occupies multiple
> >> leaves.
> >>
> >>                   leaf_A     leaf_B
> >> When checking inode item in leaf_A, assume inode[512] have file extents
> >> in leaf_B, and leaf_B is shared. In the case, for inode[512], we must
> >> visit leaf_B to have inode item check. After finishing inode[512] check,
> >> here we walk down tree root to leaf_B to check whether node or leaf
> >> is shared, if some node or leaf is shared, we can just skip it and below
> >> nodes or leaf's check.
> >>
> >> I also fill a disk partition with linux source codes and create 3 snapshots
> >> in it. Before this patch, it averagely took 46s to finish one btrfsck
> >> execution, with this patch, it averagely took 15s.
> >>
> >> Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
> > Can you please refresh the patch on top of current devel branch? I get
> > too many conflicts to resolve.
> This patch is to improve low memory mode fs/file tree check, but it seems
> Lu Fengqi's low memory fs/file tree check patches are not merged into your
> devel branch :)

Are they not? The low-memory patchset has been released in 4.7.1, the
devel branch is always on top of master branch. I see both branches
pushed to the public git repos so I don't see what you mean.

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH] btrfs-progs: check: skip shared node or leaf check for low_memory mode
  2016-08-29 15:20     ` David Sterba
@ 2016-08-30  1:50       ` Qu Wenruo
  2016-08-30 11:32         ` David Sterba
  0 siblings, 1 reply; 8+ messages in thread
From: Qu Wenruo @ 2016-08-30  1:50 UTC (permalink / raw)
  To: dsterba, Wang Xiaoguang, linux-btrfs



At 08/29/2016 11:20 PM, David Sterba wrote:
> On Thu, Aug 25, 2016 at 01:30:09PM +0800, Wang Xiaoguang wrote:
>> Hi,
>>
>> On 08/24/2016 08:44 PM, David Sterba wrote:
>>> On Fri, Aug 19, 2016 at 05:59:46PM +0800, Wang Xiaoguang wrote:
>>>> The basic idea is simple. Assume a middle tree node A is shared and
>>>> its referenceing fs/file tree root ids are 5, 258 and 260, then we
>>>> only check node A in the tree who has the smallest root id. That means
>>>> in this case, when checking root tree(5), we check inode A, for root
>>>> tree 258 and 260, we can just skip it.
>>>>
>>>> Notice even with this patch, we still may visit a shared node or leaf
>>>> multiple times. This happens when a inode metadata occupies multiple
>>>> leaves.
>>>>
>>>>                   leaf_A     leaf_B
>>>> When checking inode item in leaf_A, assume inode[512] have file extents
>>>> in leaf_B, and leaf_B is shared. In the case, for inode[512], we must
>>>> visit leaf_B to have inode item check. After finishing inode[512] check,
>>>> here we walk down tree root to leaf_B to check whether node or leaf
>>>> is shared, if some node or leaf is shared, we can just skip it and below
>>>> nodes or leaf's check.
>>>>
>>>> I also fill a disk partition with linux source codes and create 3 snapshots
>>>> in it. Before this patch, it averagely took 46s to finish one btrfsck
>>>> execution, with this patch, it averagely took 15s.
>>>>
>>>> Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
>>> Can you please refresh the patch on top of current devel branch? I get
>>> too many conflicts to resolve.
>> This patch is to improve low memory mode fs/file tree check, but it seems
>> Lu Fengqi's low memory fs/file tree check patches are not merged into your
>> devel branch :)
>
> Are they not? The low-memory patchset has been released in 4.7.1, the
> devel branch is always on top of master branch. I see both branches
> pushed to the public git repos so I don't see what you mean.

Unfortunately, the low memory mode is not fully merged into devel branch.

Only the first part (extent and chunk tree) is merged.

The second part(fs tree) is not merged yet.

Patches like the following is not in either devel/master branch:
Lu Fengqi (13):
   btrfs-progs: move btrfs_extref_hash() to hash.h
   btrfs-progs: check: introduce function to find dir_item
   btrfs-progs: check: introduce function to check inode_ref
   btrfs-progs: check: introduce function to check inode_extref
   btrfs-progs: check: introduce function to find inode_ref
   btrfs-progs: check: introduce a function to check dir_item
   btrfs-progs: check: introduce function to check file extent
   btrfs-progs: check: introduce function to check inode item
   btrfs-progs: check: introduce function to check fs root
   btrfs-progs: check: introduce function to check root ref
   btrfs-progs: check: introduce low_memory mode fs_tree check
   btrfs-progs: check: fix the return value bug of cmd_check()
   btrfs-progs: check: fix false warning for check_extent_item()

So Wang found it confusing and unable to apply his patch to devel branch.

Thanks,
Qu


> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
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>
>



^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH] btrfs-progs: check: skip shared node or leaf check for low_memory mode
  2016-08-30  1:50       ` Qu Wenruo
@ 2016-08-30 11:32         ` David Sterba
  2016-08-30 11:44           ` Wang Xiaoguang
  0 siblings, 1 reply; 8+ messages in thread
From: David Sterba @ 2016-08-30 11:32 UTC (permalink / raw)
  To: Qu Wenruo; +Cc: Wang Xiaoguang, linux-btrfs

On Tue, Aug 30, 2016 at 09:50:20AM +0800, Qu Wenruo wrote:
> > Are they not? The low-memory patchset has been released in 4.7.1, the
> > devel branch is always on top of master branch. I see both branches
> > pushed to the public git repos so I don't see what you mean.
> 
> Unfortunately, the low memory mode is not fully merged into devel branch.
> 
> Only the first part (extent and chunk tree) is merged.
> 
> The second part(fs tree) is not merged yet.
> 
> Patches like the following is not in either devel/master branch:
> Lu Fengqi (13):
>    btrfs-progs: move btrfs_extref_hash() to hash.h
>    btrfs-progs: check: introduce function to find dir_item
>    btrfs-progs: check: introduce function to check inode_ref
>    btrfs-progs: check: introduce function to check inode_extref
>    btrfs-progs: check: introduce function to find inode_ref
>    btrfs-progs: check: introduce a function to check dir_item
>    btrfs-progs: check: introduce function to check file extent
>    btrfs-progs: check: introduce function to check inode item
>    btrfs-progs: check: introduce function to check fs root
>    btrfs-progs: check: introduce function to check root ref
>    btrfs-progs: check: introduce low_memory mode fs_tree check
>    btrfs-progs: check: fix the return value bug of cmd_check()
>    btrfs-progs: check: fix false warning for check_extent_item()
> 
> So Wang found it confusing and unable to apply his patch to devel branch.

He could have replied himself, I think the conversation would feel
better when we can talk directly :)

So the situation with the patchset is a bit messed up. I thought there
was only one patchset for the low-memory mode as the subjects are hard
to tell appart "introduce something" 20 times. I should have spotted
that, but you know how many patches float in the mailinglist, mistakes
happen.

Now that I know where the problem is, I'll add the remaining patches to
devel and release in next or next-next round, depending on the review.

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH] btrfs-progs: check: skip shared node or leaf check for low_memory mode
  2016-08-30 11:32         ` David Sterba
@ 2016-08-30 11:44           ` Wang Xiaoguang
  2016-08-30 12:08             ` David Sterba
  0 siblings, 1 reply; 8+ messages in thread
From: Wang Xiaoguang @ 2016-08-30 11:44 UTC (permalink / raw)
  To: dsterba, Qu Wenruo, linux-btrfs

Hi,

On 08/30/2016 07:32 PM, David Sterba wrote:
> On Tue, Aug 30, 2016 at 09:50:20AM +0800, Qu Wenruo wrote:
>>> Are they not? The low-memory patchset has been released in 4.7.1, the
>>> devel branch is always on top of master branch. I see both branches
>>> pushed to the public git repos so I don't see what you mean.
>> Unfortunately, the low memory mode is not fully merged into devel branch.
>>
>> Only the first part (extent and chunk tree) is merged.
>>
>> The second part(fs tree) is not merged yet.
>>
>> Patches like the following is not in either devel/master branch:
>> Lu Fengqi (13):
>>     btrfs-progs: move btrfs_extref_hash() to hash.h
>>     btrfs-progs: check: introduce function to find dir_item
>>     btrfs-progs: check: introduce function to check inode_ref
>>     btrfs-progs: check: introduce function to check inode_extref
>>     btrfs-progs: check: introduce function to find inode_ref
>>     btrfs-progs: check: introduce a function to check dir_item
>>     btrfs-progs: check: introduce function to check file extent
>>     btrfs-progs: check: introduce function to check inode item
>>     btrfs-progs: check: introduce function to check fs root
>>     btrfs-progs: check: introduce function to check root ref
>>     btrfs-progs: check: introduce low_memory mode fs_tree check
>>     btrfs-progs: check: fix the return value bug of cmd_check()
>>     btrfs-progs: check: fix false warning for check_extent_item()
>>
>> So Wang found it confusing and unable to apply his patch to devel branch.
> He could have replied himself, I think the conversation would feel
> better when we can talk directly :)
Yes, I agree. I was on leave for a while this morning :)

Regards,
Xiaoguang Wang
>
> So the situation with the patchset is a bit messed up. I thought there
> was only one patchset for the low-memory mode as the subjects are hard
> to tell appart "introduce something" 20 times. I should have spotted
> that, but you know how many patches float in the mailinglist, mistakes
> happen.
>
> Now that I know where the problem is, I'll add the remaining patches to
> devel and release in next or next-next round, depending on the review.
>
>




^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH] btrfs-progs: check: skip shared node or leaf check for low_memory mode
  2016-08-30 11:44           ` Wang Xiaoguang
@ 2016-08-30 12:08             ` David Sterba
  0 siblings, 0 replies; 8+ messages in thread
From: David Sterba @ 2016-08-30 12:08 UTC (permalink / raw)
  To: Wang Xiaoguang; +Cc: Qu Wenruo, linux-btrfs

On Tue, Aug 30, 2016 at 07:44:17PM +0800, Wang Xiaoguang wrote:
> Hi,
> 
> On 08/30/2016 07:32 PM, David Sterba wrote:
> > On Tue, Aug 30, 2016 at 09:50:20AM +0800, Qu Wenruo wrote:
> >>> Are they not? The low-memory patchset has been released in 4.7.1, the
> >>> devel branch is always on top of master branch. I see both branches
> >>> pushed to the public git repos so I don't see what you mean.
> >> Unfortunately, the low memory mode is not fully merged into devel branch.
> >>
> >> Only the first part (extent and chunk tree) is merged.
> >>
> >> The second part(fs tree) is not merged yet.
> >>
> >> Patches like the following is not in either devel/master branch:
> >> Lu Fengqi (13):
> >>     btrfs-progs: move btrfs_extref_hash() to hash.h
> >>     btrfs-progs: check: introduce function to find dir_item
> >>     btrfs-progs: check: introduce function to check inode_ref
> >>     btrfs-progs: check: introduce function to check inode_extref
> >>     btrfs-progs: check: introduce function to find inode_ref
> >>     btrfs-progs: check: introduce a function to check dir_item
> >>     btrfs-progs: check: introduce function to check file extent
> >>     btrfs-progs: check: introduce function to check inode item
> >>     btrfs-progs: check: introduce function to check fs root
> >>     btrfs-progs: check: introduce function to check root ref
> >>     btrfs-progs: check: introduce low_memory mode fs_tree check
> >>     btrfs-progs: check: fix the return value bug of cmd_check()
> >>     btrfs-progs: check: fix false warning for check_extent_item()
> >>
> >> So Wang found it confusing and unable to apply his patch to devel branch.
> > He could have replied himself, I think the conversation would feel
> > better when we can talk directly :)
> Yes, I agree. I was on leave for a while this morning :)

Doh, I may be confused by the names, I mean that I've never seen a mail
from 'Lu Fengqi'.

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2016-08-30 12:10 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-08-19  9:59 [PATCH] btrfs-progs: check: skip shared node or leaf check for low_memory mode Wang Xiaoguang
2016-08-24 12:44 ` David Sterba
2016-08-25  5:30   ` Wang Xiaoguang
2016-08-29 15:20     ` David Sterba
2016-08-30  1:50       ` Qu Wenruo
2016-08-30 11:32         ` David Sterba
2016-08-30 11:44           ` Wang Xiaoguang
2016-08-30 12:08             ` David Sterba

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