[PATCH v2 0/3] Qgroup fix for dirty hack routines

[PATCH v2 0/3] Qgroup fix for dirty hack routines

[Qu Wenruo]

This patchset introduce 2 fixes for data extent owner hacks.

One can be triggered by balance, another one can be trigged by log replay
after power loss.

Root cause are all similar: EXTENT_DATA owner is changed by dirty
hacks, from swapping tree blocks containing EXTENT_DATA to manually
update extent backref without using inc/dec_extent_ref.

The first patch introduces needed functions, then 2 fixes.

The reproducer are all merged into xfstests, btrfs/123 and btrfs/119.

3rd patch stay untouched while 2nd patch get update thanks for the report
from Goldwyn.

Changelog:
v2:
  Update 2nd patch to handle cases where the whole subtree, not only
  level 2 nodes get updated.
v3:
  Function name update. Thanks Goldwyn.
  Rename 'btrfs_qgroup_insert_dirty_extent()' to
  'btrfs_qgroup_insert_dirty_extent_nolock()'
  Rename 'btrfs_qgroup_record_dirty_extent()' to
  'btrfs_qgroup_insert_dirty_extent()'


Qu Wenruo (3):
  btrfs: qgroup: Refactor btrfs_qgroup_insert_dirty_extent()
  btrfs: relocation: Fix leaking qgroups numbers on data extents
  btrfs: qgroup: Fix qgroup incorrectness caused by log replay

 fs/btrfs/delayed-ref.c |   7 +--
 fs/btrfs/extent-tree.c |  37 +++-------------
 fs/btrfs/qgroup.c      |  41 +++++++++++++++---
 fs/btrfs/qgroup.h      |  33 ++++++++++++--
 fs/btrfs/relocation.c  | 114 ++++++++++++++++++++++++++++++++++++++++++++++---
 fs/btrfs/tree-log.c    |  16 +++++++
 6 files changed, 195 insertions(+), 53 deletions(-)

-- 
2.9.2

[PATCH v3 1/3] btrfs: qgroup: Refactor btrfs_qgroup_insert_dirty_extent()

[Qu Wenruo]

Refactor btrfs_qgroup_insert_dirty_extent() function, to two functions:
1. _btrfs_qgroup_insert_dirty_extent()
   Almost the same with original code.
   For delayed_ref usage, which has delayed refs locked.

   Change the return value type to int, since caller never needs the
   pointer, but only needs to know if they need to free the allocated
   memory.

2. btrfs_qgroup_record_dirty_extent()
   The more encapsulated version.

   Will do the delayed_refs lock, memory allocation, quota enabled check
   and other misc things.

The original design is to keep exported functions to minimal, but since
more btrfs hacks exposed, like replacing path in balance, needs us to
record dirty extents manually, so we have to add such functions.

Also, add comment for both functions, to info developers how to keep
qgroup correct when doing hacks.

Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.de>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
---
 fs/btrfs/delayed-ref.c |  7 ++-----
 fs/btrfs/extent-tree.c | 37 +++++--------------------------------
 fs/btrfs/qgroup.c      | 41 +++++++++++++++++++++++++++++++++++------
 fs/btrfs/qgroup.h      | 33 +++++++++++++++++++++++++++++----
 4 files changed, 71 insertions(+), 47 deletions(-)

diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index b6d210e..dd9b101 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -541,7 +541,6 @@ add_delayed_ref_head(struct btrfs_fs_info *fs_info,
 	struct btrfs_delayed_ref_head *existing;
 	struct btrfs_delayed_ref_head *head_ref = NULL;
 	struct btrfs_delayed_ref_root *delayed_refs;
-	struct btrfs_qgroup_extent_record *qexisting;
 	int count_mod = 1;
 	int must_insert_reserved = 0;
 
@@ -606,10 +605,8 @@ add_delayed_ref_head(struct btrfs_fs_info *fs_info,
 		qrecord->num_bytes = num_bytes;
 		qrecord->old_roots = NULL;
 
-		qexisting = btrfs_qgroup_insert_dirty_extent(fs_info,
-							     delayed_refs,
-							     qrecord);
-		if (qexisting)
+		if(btrfs_qgroup_insert_dirty_extent_nolock(fs_info,
+					delayed_refs, qrecord))
 			kfree(qrecord);
 	}
 
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index c2b81b0..2a860c9 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -8521,35 +8521,6 @@ reada:
 	wc->reada_slot = slot;
 }
 
-/*
- * These may not be seen by the usual inc/dec ref code so we have to
- * add them here.
- */
-static int record_one_subtree_extent(struct btrfs_trans_handle *trans,
-				     struct btrfs_root *root, u64 bytenr,
-				     u64 num_bytes)
-{
-	struct btrfs_qgroup_extent_record *qrecord;
-	struct btrfs_delayed_ref_root *delayed_refs;
-
-	qrecord = kmalloc(sizeof(*qrecord), GFP_NOFS);
-	if (!qrecord)
-		return -ENOMEM;
-
-	qrecord->bytenr = bytenr;
-	qrecord->num_bytes = num_bytes;
-	qrecord->old_roots = NULL;
-
-	delayed_refs = &trans->transaction->delayed_refs;
-	spin_lock(&delayed_refs->lock);
-	if (btrfs_qgroup_insert_dirty_extent(trans->fs_info,
-					     delayed_refs, qrecord))
-		kfree(qrecord);
-	spin_unlock(&delayed_refs->lock);
-
-	return 0;
-}
-
 static int account_leaf_items(struct btrfs_trans_handle *trans,
 			      struct btrfs_root *root,
 			      struct extent_buffer *eb)
@@ -8583,7 +8554,8 @@ static int account_leaf_items(struct btrfs_trans_handle *trans,
 
 		num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
 
-		ret = record_one_subtree_extent(trans, root, bytenr, num_bytes);
+		ret = btrfs_qgroup_insert_dirty_extent(trans, root->fs_info,
+				bytenr, num_bytes, GFP_NOFS);
 		if (ret)
 			return ret;
 	}
@@ -8732,8 +8704,9 @@ walk_down:
 			btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
 			path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
 
-			ret = record_one_subtree_extent(trans, root, child_bytenr,
-							root->nodesize);
+			ret = btrfs_qgroup_insert_dirty_extent(trans,
+					root->fs_info, child_bytenr,
+					root->nodesize, GFP_NOFS);
 			if (ret)
 				goto out;
 		}
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 93ee1c1..1f29693 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1453,10 +1453,9 @@ int btrfs_qgroup_prepare_account_extents(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
-struct btrfs_qgroup_extent_record *
-btrfs_qgroup_insert_dirty_extent(struct btrfs_fs_info *fs_info,
-				 struct btrfs_delayed_ref_root *delayed_refs,
-				 struct btrfs_qgroup_extent_record *record)
+int btrfs_qgroup_insert_dirty_extent_nolock(struct btrfs_fs_info *fs_info,
+				struct btrfs_delayed_ref_root *delayed_refs,
+				struct btrfs_qgroup_extent_record *record)
 {
 	struct rb_node **p = &delayed_refs->dirty_extent_root.rb_node;
 	struct rb_node *parent_node = NULL;
@@ -1475,12 +1474,42 @@ btrfs_qgroup_insert_dirty_extent(struct btrfs_fs_info *fs_info,
 		else if (bytenr > entry->bytenr)
 			p = &(*p)->rb_right;
 		else
-			return entry;
+			return 1;
 	}
 
 	rb_link_node(&record->node, parent_node, p);
 	rb_insert_color(&record->node, &delayed_refs->dirty_extent_root);
-	return NULL;
+	return 0;
+}
+
+int btrfs_qgroup_insert_dirty_extent(struct btrfs_trans_handle *trans,
+		struct btrfs_fs_info *fs_info, u64 bytenr, u64 num_bytes,
+		gfp_t gfp_flag)
+{
+	struct btrfs_qgroup_extent_record *record;
+	struct btrfs_delayed_ref_root *delayed_refs;
+	int ret;
+
+	if (!fs_info->quota_enabled || bytenr == 0 || num_bytes == 0)
+		return 0;
+	if (WARN_ON(trans == NULL))
+		return -EINVAL;
+	record = kmalloc(sizeof(*record), gfp_flag);
+	if (!record)
+		return -ENOMEM;
+
+	delayed_refs = &trans->transaction->delayed_refs;
+	record->bytenr = bytenr;
+	record->num_bytes = num_bytes;
+	record->old_roots = NULL;
+
+	spin_lock(&delayed_refs->lock);
+	ret = btrfs_qgroup_insert_dirty_extent_nolock(fs_info, delayed_refs,
+						      record);
+	spin_unlock(&delayed_refs->lock);
+	if (ret > 0)
+		kfree(record);
+	return 0;
 }
 
 #define UPDATE_NEW	0
diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
index 710887c..f6a38e4 100644
--- a/fs/btrfs/qgroup.h
+++ b/fs/btrfs/qgroup.h
@@ -63,10 +63,35 @@ void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info);
 struct btrfs_delayed_extent_op;
 int btrfs_qgroup_prepare_account_extents(struct btrfs_trans_handle *trans,
 					 struct btrfs_fs_info *fs_info);
-struct btrfs_qgroup_extent_record *
-btrfs_qgroup_insert_dirty_extent(struct btrfs_fs_info *fs_info,
-				 struct btrfs_delayed_ref_root *delayed_refs,
-				 struct btrfs_qgroup_extent_record *record);
+/*
+ * Insert one dirty extent record into @delayed_refs, informing qgroup to
+ * account that extent at commit trans time.
+ *
+ * No lock version, caller must acquire delayed ref lock and allocate memory.
+ *
+ * Return 0 for success insert
+ * Return >0 for existing record, caller can free @record safely.
+ * Error is not possible
+ */
+int btrfs_qgroup_insert_dirty_extent_nolock(
+		struct btrfs_fs_info *fs_info,
+		struct btrfs_delayed_ref_root *delayed_refs,
+		struct btrfs_qgroup_extent_record *record);
+
+/*
+ * Insert one dirty extent record into @delayed_refs, informing qgroup to
+ * account that extent at commit trans time.
+ *
+ * Better encapsulated version.
+ *
+ * Return 0 if the operation is done.
+ * Return <0 for error, like memory allocation failure or invalid parameter
+ * (NULL trans)
+ */
+int btrfs_qgroup_insert_dirty_extent(struct btrfs_trans_handle *trans,
+		struct btrfs_fs_info *fs_info, u64 bytenr, u64 num_bytes,
+		gfp_t gfp_flag);
+
 int
 btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans,
 			    struct btrfs_fs_info *fs_info,
-- 
2.9.2

[PATCH v3 2/3] btrfs: relocation: Fix leaking qgroups numbers on data extents

[Qu Wenruo]

When balancing data extents, qgroup will leak all its numbers for
relocated data extents.

The relocation is done in the following steps for data extents:
1) Create data reloc tree and inode
2) Copy all data extents to data reloc tree
   And commit transaction
3) Create tree reloc tree(special snapshot) for any related subvolumes
4) Replace file extent in tree reloc tree with new extents in data reloc
   tree
   And commit transaction
5) Merge tree reloc tree with original fs, by swapping tree blocks

For 1)~4), since tree reloc tree and data reloc tree doesn't count to
qgroup, everything is OK.

But for 5), the swapping of tree blocks will only info qgroup to track
metadata extents.

If metadata extents contain file extents, qgroup number for file extents
will get lost, leading to corrupted qgroup accounting.

The fix is, before commit transaction of step 5), manually info qgroup to
track all file extents in data reloc tree.
Since at commit transaction time, the tree swapping is done, and qgroup
will account these data extents correctly.

Cc: Mark Fasheh <mfasheh@suse.de>
Reported-by: Mark Fasheh <mfasheh@suse.de>
Reported-by: Filipe Manana <fdmanana@gmail.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
---
 fs/btrfs/relocation.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 108 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index b26a5ae..a6ace8a 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -31,6 +31,7 @@
 #include "async-thread.h"
 #include "free-space-cache.h"
 #include "inode-map.h"
+#include "qgroup.h"
 
 /*
  * backref_node, mapping_node and tree_block start with this
@@ -3916,6 +3917,95 @@ int prepare_to_relocate(struct reloc_control *rc)
 	return 0;
 }
 
+/*
+ * Qgroup fixer for data chunk relocation.
+ * The data relocation is done in the following steps
+ * 1) Copy data extents into data reloc tree
+ * 2) Create tree reloc tree(special snapshot) for related subvolumes
+ * 3) Modify file extents in tree reloc tree
+ * 4) Merge tree reloc tree with original fs tree, by swapping tree blocks
+ *
+ * The problem is, data and tree reloc tree are not accounted to qgroup,
+ * and 4) will only info qgroup to track tree blocks change, not file extents
+ * in the tree blocks.
+ *
+ * The good news is, related data extents are all in data reloc tree, so we
+ * only need to info qgroup to track all file extents in data reloc tree
+ * before commit trans.
+ */
+static int qgroup_fix_relocated_data_extents(struct btrfs_trans_handle *trans,
+					     struct reloc_control *rc)
+{
+	struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
+	struct inode *inode = rc->data_inode;
+	struct btrfs_root *data_reloc_root = BTRFS_I(inode)->root;
+	struct btrfs_path *path;
+	struct btrfs_key key;
+	int ret = 0;
+
+	if (!fs_info->quota_enabled)
+		return 0;
+
+	/*
+	 * Only for stage where we update data pointers the qgroup fix is
+	 * valid.
+	 * For MOVING_DATA stage, we will miss the timing of swapping tree
+	 * blocks, and won't fix it.
+	 */
+	if (!(rc->stage == UPDATE_DATA_PTRS && rc->extents_found))
+		return 0;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+	key.objectid = btrfs_ino(inode);
+	key.type = BTRFS_EXTENT_DATA_KEY;
+	key.offset = 0;
+
+	ret = btrfs_search_slot(NULL, data_reloc_root, &key, path, 0, 0);
+	if (ret < 0)
+		goto out;
+
+	lock_extent(&BTRFS_I(inode)->io_tree, 0, (u64)-1);
+	while (1) {
+		struct btrfs_file_extent_item *fi;
+
+		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
+		if (key.objectid > btrfs_ino(inode))
+			break;
+		if (key.type != BTRFS_EXTENT_DATA_KEY)
+			goto next;
+		fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
+				    struct btrfs_file_extent_item);
+		if (btrfs_file_extent_type(path->nodes[0], fi) !=
+				BTRFS_FILE_EXTENT_REG)
+			goto next;
+		/*
+		pr_info("disk bytenr: %llu, num_bytes: %llu\n",
+			btrfs_file_extent_disk_bytenr(path->nodes[0], fi),
+			btrfs_file_extent_disk_num_bytes(path->nodes[0], fi));
+			*/
+		ret = btrfs_qgroup_insert_dirty_extent(trans, fs_info,
+			btrfs_file_extent_disk_bytenr(path->nodes[0], fi),
+			btrfs_file_extent_disk_num_bytes(path->nodes[0], fi),
+			GFP_NOFS);
+		if (ret < 0)
+			break;
+next:
+		ret = btrfs_next_item(data_reloc_root, path);
+		if (ret < 0)
+			break;
+		if (ret > 0) {
+			ret = 0;
+			break;
+		}
+	}
+	unlock_extent(&BTRFS_I(inode)->io_tree, 0 , (u64)-1);
+out:
+	btrfs_free_path(path);
+	return ret;
+}
+
 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
 {
 	struct rb_root blocks = RB_ROOT;
@@ -4102,10 +4192,16 @@ restart:
 
 	/* get rid of pinned extents */
 	trans = btrfs_join_transaction(rc->extent_root);
-	if (IS_ERR(trans))
+	if (IS_ERR(trans)) {
 		err = PTR_ERR(trans);
-	else
-		btrfs_commit_transaction(trans, rc->extent_root);
+		goto out_free;
+	}
+	err = qgroup_fix_relocated_data_extents(trans, rc);
+	if (err < 0) {
+		btrfs_abort_transaction(trans, err);
+		goto out_free;
+	}
+	btrfs_commit_transaction(trans, rc->extent_root);
 out_free:
 	btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
 	btrfs_free_path(path);
@@ -4468,10 +4564,16 @@ int btrfs_recover_relocation(struct btrfs_root *root)
 	unset_reloc_control(rc);
 
 	trans = btrfs_join_transaction(rc->extent_root);
-	if (IS_ERR(trans))
+	if (IS_ERR(trans)) {
 		err = PTR_ERR(trans);
-	else
-		err = btrfs_commit_transaction(trans, rc->extent_root);
+		goto out_free;
+	}
+	err = qgroup_fix_relocated_data_extents(trans, rc);
+	if (err < 0) {
+		btrfs_abort_transaction(trans, err);
+		goto out_free;
+	}
+	err = btrfs_commit_transaction(trans, rc->extent_root);
 out_free:
 	kfree(rc);
 out:
-- 
2.9.2

[PATCH v3 3/3] btrfs: qgroup: Fix qgroup incorrectness caused by log replay

[Qu Wenruo]

When doing log replay at mount time(after power loss), qgroup will leak
numbers of replayed data extents.

The cause is almost the same of balance.
So fix it by manually informing qgroup for owner changed extents.

The bug can be detected by btrfs/119 test case.

Cc: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
---
 fs/btrfs/tree-log.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index d31a0c4..9d9cb07 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -27,6 +27,7 @@
 #include "backref.h"
 #include "hash.h"
 #include "compression.h"
+#include "qgroup.h"
 
 /* magic values for the inode_only field in btrfs_log_inode:
  *
@@ -680,6 +681,21 @@ static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
 		ins.type = BTRFS_EXTENT_ITEM_KEY;
 		offset = key->offset - btrfs_file_extent_offset(eb, item);
 
+		/*
+		 * Manually record dirty extent, as here we did a shallow
+		 * file extent item copy and skip normal backref update,
+		 * but modifying extent tree all by ourselves.
+		 * So need to manually record dirty extent for qgroup,
+		 * as the owner of the file extent changed from log tree
+		 * (doesn't affect qgroup) to fs/file tree(affects qgroup)
+		 */
+		ret = btrfs_qgroup_insert_dirty_extent(trans, root->fs_info,
+				btrfs_file_extent_disk_bytenr(eb, item),
+				btrfs_file_extent_disk_num_bytes(eb, item),
+				GFP_NOFS);
+		if (ret < 0)
+			goto out;
+
 		if (ins.objectid > 0) {
 			u64 csum_start;
 			u64 csum_end;
-- 
2.9.2

Re: [PATCH v3 1/3] btrfs: qgroup: Refactor btrfs_qgroup_insert_dirty_extent()

[Goldwyn Rodrigues]

On 08/09/2016 03:30 AM, Qu Wenruo wrote:
> Refactor btrfs_qgroup_insert_dirty_extent() function, to two functions:
> 1. _btrfs_qgroup_insert_dirty_extent()
>    Almost the same with original code.
>    For delayed_ref usage, which has delayed refs locked.
> 
>    Change the return value type to int, since caller never needs the
>    pointer, but only needs to know if they need to free the allocated
>    memory.
> 
> 2. btrfs_qgroup_record_dirty_extent()
>    The more encapsulated version.
> 
>    Will do the delayed_refs lock, memory allocation, quota enabled check
>    and other misc things.
> 
> The original design is to keep exported functions to minimal, but since
> more btrfs hacks exposed, like replacing path in balance, needs us to
> record dirty extents manually, so we have to add such functions.
> 
> Also, add comment for both functions, to info developers how to keep
> qgroup correct when doing hacks.
> 
> Cc: Mark Fasheh <mfasheh@suse.de>
> Cc: Goldwyn Rodrigues <rgoldwyn@suse.de>
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>

Reviewed-and-Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com>

> ---
>  fs/btrfs/delayed-ref.c |  7 ++-----
>  fs/btrfs/extent-tree.c | 37 +++++--------------------------------
>  fs/btrfs/qgroup.c      | 41 +++++++++++++++++++++++++++++++++++------
>  fs/btrfs/qgroup.h      | 33 +++++++++++++++++++++++++++++----
>  4 files changed, 71 insertions(+), 47 deletions(-)
> 
> diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
> index b6d210e..dd9b101 100644
> --- a/fs/btrfs/delayed-ref.c
> +++ b/fs/btrfs/delayed-ref.c
> @@ -541,7 +541,6 @@ add_delayed_ref_head(struct btrfs_fs_info *fs_info,
>  	struct btrfs_delayed_ref_head *existing;
>  	struct btrfs_delayed_ref_head *head_ref = NULL;
>  	struct btrfs_delayed_ref_root *delayed_refs;
> -	struct btrfs_qgroup_extent_record *qexisting;
>  	int count_mod = 1;
>  	int must_insert_reserved = 0;
>  
> @@ -606,10 +605,8 @@ add_delayed_ref_head(struct btrfs_fs_info *fs_info,
>  		qrecord->num_bytes = num_bytes;
>  		qrecord->old_roots = NULL;
>  
> -		qexisting = btrfs_qgroup_insert_dirty_extent(fs_info,
> -							     delayed_refs,
> -							     qrecord);
> -		if (qexisting)
> +		if(btrfs_qgroup_insert_dirty_extent_nolock(fs_info,
> +					delayed_refs, qrecord))
>  			kfree(qrecord);
>  	}
>  
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index c2b81b0..2a860c9 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -8521,35 +8521,6 @@ reada:
>  	wc->reada_slot = slot;
>  }
>  
> -/*
> - * These may not be seen by the usual inc/dec ref code so we have to
> - * add them here.
> - */
> -static int record_one_subtree_extent(struct btrfs_trans_handle *trans,
> -				     struct btrfs_root *root, u64 bytenr,
> -				     u64 num_bytes)
> -{
> -	struct btrfs_qgroup_extent_record *qrecord;
> -	struct btrfs_delayed_ref_root *delayed_refs;
> -
> -	qrecord = kmalloc(sizeof(*qrecord), GFP_NOFS);
> -	if (!qrecord)
> -		return -ENOMEM;
> -
> -	qrecord->bytenr = bytenr;
> -	qrecord->num_bytes = num_bytes;
> -	qrecord->old_roots = NULL;
> -
> -	delayed_refs = &trans->transaction->delayed_refs;
> -	spin_lock(&delayed_refs->lock);
> -	if (btrfs_qgroup_insert_dirty_extent(trans->fs_info,
> -					     delayed_refs, qrecord))
> -		kfree(qrecord);
> -	spin_unlock(&delayed_refs->lock);
> -
> -	return 0;
> -}
> -
>  static int account_leaf_items(struct btrfs_trans_handle *trans,
>  			      struct btrfs_root *root,
>  			      struct extent_buffer *eb)
> @@ -8583,7 +8554,8 @@ static int account_leaf_items(struct btrfs_trans_handle *trans,
>  
>  		num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
>  
> -		ret = record_one_subtree_extent(trans, root, bytenr, num_bytes);
> +		ret = btrfs_qgroup_insert_dirty_extent(trans, root->fs_info,
> +				bytenr, num_bytes, GFP_NOFS);
>  		if (ret)
>  			return ret;
>  	}
> @@ -8732,8 +8704,9 @@ walk_down:
>  			btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
>  			path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
>  
> -			ret = record_one_subtree_extent(trans, root, child_bytenr,
> -							root->nodesize);
> +			ret = btrfs_qgroup_insert_dirty_extent(trans,
> +					root->fs_info, child_bytenr,
> +					root->nodesize, GFP_NOFS);
>  			if (ret)
>  				goto out;
>  		}
> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
> index 93ee1c1..1f29693 100644
> --- a/fs/btrfs/qgroup.c
> +++ b/fs/btrfs/qgroup.c
> @@ -1453,10 +1453,9 @@ int btrfs_qgroup_prepare_account_extents(struct btrfs_trans_handle *trans,
>  	return ret;
>  }
>  
> -struct btrfs_qgroup_extent_record *
> -btrfs_qgroup_insert_dirty_extent(struct btrfs_fs_info *fs_info,
> -				 struct btrfs_delayed_ref_root *delayed_refs,
> -				 struct btrfs_qgroup_extent_record *record)
> +int btrfs_qgroup_insert_dirty_extent_nolock(struct btrfs_fs_info *fs_info,
> +				struct btrfs_delayed_ref_root *delayed_refs,
> +				struct btrfs_qgroup_extent_record *record)
>  {
>  	struct rb_node **p = &delayed_refs->dirty_extent_root.rb_node;
>  	struct rb_node *parent_node = NULL;
> @@ -1475,12 +1474,42 @@ btrfs_qgroup_insert_dirty_extent(struct btrfs_fs_info *fs_info,
>  		else if (bytenr > entry->bytenr)
>  			p = &(*p)->rb_right;
>  		else
> -			return entry;
> +			return 1;
>  	}
>  
>  	rb_link_node(&record->node, parent_node, p);
>  	rb_insert_color(&record->node, &delayed_refs->dirty_extent_root);
> -	return NULL;
> +	return 0;
> +}
> +
> +int btrfs_qgroup_insert_dirty_extent(struct btrfs_trans_handle *trans,
> +		struct btrfs_fs_info *fs_info, u64 bytenr, u64 num_bytes,
> +		gfp_t gfp_flag)
> +{
> +	struct btrfs_qgroup_extent_record *record;
> +	struct btrfs_delayed_ref_root *delayed_refs;
> +	int ret;
> +
> +	if (!fs_info->quota_enabled || bytenr == 0 || num_bytes == 0)
> +		return 0;
> +	if (WARN_ON(trans == NULL))
> +		return -EINVAL;
> +	record = kmalloc(sizeof(*record), gfp_flag);
> +	if (!record)
> +		return -ENOMEM;
> +
> +	delayed_refs = &trans->transaction->delayed_refs;
> +	record->bytenr = bytenr;
> +	record->num_bytes = num_bytes;
> +	record->old_roots = NULL;
> +
> +	spin_lock(&delayed_refs->lock);
> +	ret = btrfs_qgroup_insert_dirty_extent_nolock(fs_info, delayed_refs,
> +						      record);
> +	spin_unlock(&delayed_refs->lock);
> +	if (ret > 0)
> +		kfree(record);
> +	return 0;
>  }
>  
>  #define UPDATE_NEW	0
> diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
> index 710887c..f6a38e4 100644
> --- a/fs/btrfs/qgroup.h
> +++ b/fs/btrfs/qgroup.h
> @@ -63,10 +63,35 @@ void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info);
>  struct btrfs_delayed_extent_op;
>  int btrfs_qgroup_prepare_account_extents(struct btrfs_trans_handle *trans,
>  					 struct btrfs_fs_info *fs_info);
> -struct btrfs_qgroup_extent_record *
> -btrfs_qgroup_insert_dirty_extent(struct btrfs_fs_info *fs_info,
> -				 struct btrfs_delayed_ref_root *delayed_refs,
> -				 struct btrfs_qgroup_extent_record *record);
> +/*
> + * Insert one dirty extent record into @delayed_refs, informing qgroup to
> + * account that extent at commit trans time.
> + *
> + * No lock version, caller must acquire delayed ref lock and allocate memory.
> + *
> + * Return 0 for success insert
> + * Return >0 for existing record, caller can free @record safely.
> + * Error is not possible
> + */
> +int btrfs_qgroup_insert_dirty_extent_nolock(
> +		struct btrfs_fs_info *fs_info,
> +		struct btrfs_delayed_ref_root *delayed_refs,
> +		struct btrfs_qgroup_extent_record *record);
> +
> +/*
> + * Insert one dirty extent record into @delayed_refs, informing qgroup to
> + * account that extent at commit trans time.
> + *
> + * Better encapsulated version.
> + *
> + * Return 0 if the operation is done.
> + * Return <0 for error, like memory allocation failure or invalid parameter
> + * (NULL trans)
> + */
> +int btrfs_qgroup_insert_dirty_extent(struct btrfs_trans_handle *trans,
> +		struct btrfs_fs_info *fs_info, u64 bytenr, u64 num_bytes,
> +		gfp_t gfp_flag);
> +
>  int
>  btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans,
>  			    struct btrfs_fs_info *fs_info,
> 

-- 
Goldwyn

Re: [PATCH v3 2/3] btrfs: relocation: Fix leaking qgroups numbers on data extents

[Goldwyn Rodrigues]

On 08/09/2016 03:30 AM, Qu Wenruo wrote:
> When balancing data extents, qgroup will leak all its numbers for
> relocated data extents.
> 
> The relocation is done in the following steps for data extents:
> 1) Create data reloc tree and inode
> 2) Copy all data extents to data reloc tree
>    And commit transaction
> 3) Create tree reloc tree(special snapshot) for any related subvolumes
> 4) Replace file extent in tree reloc tree with new extents in data reloc
>    tree
>    And commit transaction
> 5) Merge tree reloc tree with original fs, by swapping tree blocks
> 
> For 1)~4), since tree reloc tree and data reloc tree doesn't count to
> qgroup, everything is OK.
> 
> But for 5), the swapping of tree blocks will only info qgroup to track
> metadata extents.
> 
> If metadata extents contain file extents, qgroup number for file extents
> will get lost, leading to corrupted qgroup accounting.
> 
> The fix is, before commit transaction of step 5), manually info qgroup to
> track all file extents in data reloc tree.
> Since at commit transaction time, the tree swapping is done, and qgroup
> will account these data extents correctly.
> 
> Cc: Mark Fasheh <mfasheh@suse.de>
> Reported-by: Mark Fasheh <mfasheh@suse.de>
> Reported-by: Filipe Manana <fdmanana@gmail.com>
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>

Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com>

> ---
>  fs/btrfs/relocation.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 108 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index b26a5ae..a6ace8a 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -31,6 +31,7 @@
>  #include "async-thread.h"
>  #include "free-space-cache.h"
>  #include "inode-map.h"
> +#include "qgroup.h"
>  
>  /*
>   * backref_node, mapping_node and tree_block start with this
> @@ -3916,6 +3917,95 @@ int prepare_to_relocate(struct reloc_control *rc)
>  	return 0;
>  }
>  
> +/*
> + * Qgroup fixer for data chunk relocation.
> + * The data relocation is done in the following steps
> + * 1) Copy data extents into data reloc tree
> + * 2) Create tree reloc tree(special snapshot) for related subvolumes
> + * 3) Modify file extents in tree reloc tree
> + * 4) Merge tree reloc tree with original fs tree, by swapping tree blocks
> + *
> + * The problem is, data and tree reloc tree are not accounted to qgroup,
> + * and 4) will only info qgroup to track tree blocks change, not file extents
> + * in the tree blocks.
> + *
> + * The good news is, related data extents are all in data reloc tree, so we
> + * only need to info qgroup to track all file extents in data reloc tree
> + * before commit trans.
> + */
> +static int qgroup_fix_relocated_data_extents(struct btrfs_trans_handle *trans,
> +					     struct reloc_control *rc)
> +{
> +	struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
> +	struct inode *inode = rc->data_inode;
> +	struct btrfs_root *data_reloc_root = BTRFS_I(inode)->root;
> +	struct btrfs_path *path;
> +	struct btrfs_key key;
> +	int ret = 0;
> +
> +	if (!fs_info->quota_enabled)
> +		return 0;
> +
> +	/*
> +	 * Only for stage where we update data pointers the qgroup fix is
> +	 * valid.
> +	 * For MOVING_DATA stage, we will miss the timing of swapping tree
> +	 * blocks, and won't fix it.
> +	 */
> +	if (!(rc->stage == UPDATE_DATA_PTRS && rc->extents_found))
> +		return 0;
> +
> +	path = btrfs_alloc_path();
> +	if (!path)
> +		return -ENOMEM;
> +	key.objectid = btrfs_ino(inode);
> +	key.type = BTRFS_EXTENT_DATA_KEY;
> +	key.offset = 0;
> +
> +	ret = btrfs_search_slot(NULL, data_reloc_root, &key, path, 0, 0);
> +	if (ret < 0)
> +		goto out;
> +
> +	lock_extent(&BTRFS_I(inode)->io_tree, 0, (u64)-1);
> +	while (1) {
> +		struct btrfs_file_extent_item *fi;
> +
> +		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
> +		if (key.objectid > btrfs_ino(inode))
> +			break;
> +		if (key.type != BTRFS_EXTENT_DATA_KEY)
> +			goto next;
> +		fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
> +				    struct btrfs_file_extent_item);
> +		if (btrfs_file_extent_type(path->nodes[0], fi) !=
> +				BTRFS_FILE_EXTENT_REG)
> +			goto next;
> +		/*
> +		pr_info("disk bytenr: %llu, num_bytes: %llu\n",
> +			btrfs_file_extent_disk_bytenr(path->nodes[0], fi),
> +			btrfs_file_extent_disk_num_bytes(path->nodes[0], fi));
> +			*/
> +		ret = btrfs_qgroup_insert_dirty_extent(trans, fs_info,
> +			btrfs_file_extent_disk_bytenr(path->nodes[0], fi),
> +			btrfs_file_extent_disk_num_bytes(path->nodes[0], fi),
> +			GFP_NOFS);
> +		if (ret < 0)
> +			break;
> +next:
> +		ret = btrfs_next_item(data_reloc_root, path);
> +		if (ret < 0)
> +			break;
> +		if (ret > 0) {
> +			ret = 0;
> +			break;
> +		}
> +	}
> +	unlock_extent(&BTRFS_I(inode)->io_tree, 0 , (u64)-1);
> +out:
> +	btrfs_free_path(path);
> +	return ret;
> +}
> +
>  static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
>  {
>  	struct rb_root blocks = RB_ROOT;
> @@ -4102,10 +4192,16 @@ restart:
>  
>  	/* get rid of pinned extents */
>  	trans = btrfs_join_transaction(rc->extent_root);
> -	if (IS_ERR(trans))
> +	if (IS_ERR(trans)) {
>  		err = PTR_ERR(trans);
> -	else
> -		btrfs_commit_transaction(trans, rc->extent_root);
> +		goto out_free;
> +	}
> +	err = qgroup_fix_relocated_data_extents(trans, rc);
> +	if (err < 0) {
> +		btrfs_abort_transaction(trans, err);
> +		goto out_free;
> +	}
> +	btrfs_commit_transaction(trans, rc->extent_root);
>  out_free:
>  	btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
>  	btrfs_free_path(path);
> @@ -4468,10 +4564,16 @@ int btrfs_recover_relocation(struct btrfs_root *root)
>  	unset_reloc_control(rc);
>  
>  	trans = btrfs_join_transaction(rc->extent_root);
> -	if (IS_ERR(trans))
> +	if (IS_ERR(trans)) {
>  		err = PTR_ERR(trans);
> -	else
> -		err = btrfs_commit_transaction(trans, rc->extent_root);
> +		goto out_free;
> +	}
> +	err = qgroup_fix_relocated_data_extents(trans, rc);
> +	if (err < 0) {
> +		btrfs_abort_transaction(trans, err);
> +		goto out_free;
> +	}
> +	err = btrfs_commit_transaction(trans, rc->extent_root);
>  out_free:
>  	kfree(rc);
>  out:
> 

-- 
Goldwyn

Re: [PATCH v3 3/3] btrfs: qgroup: Fix qgroup incorrectness caused by log replay

[Goldwyn Rodrigues]

On 08/09/2016 03:30 AM, Qu Wenruo wrote:
> When doing log replay at mount time(after power loss), qgroup will leak
> numbers of replayed data extents.
> 
> The cause is almost the same of balance.
> So fix it by manually informing qgroup for owner changed extents.
> 
> The bug can be detected by btrfs/119 test case.
> 
> Cc: Mark Fasheh <mfasheh@suse.de>
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>

Reviewed-and-Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com>

> ---
>  fs/btrfs/tree-log.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index d31a0c4..9d9cb07 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -27,6 +27,7 @@
>  #include "backref.h"
>  #include "hash.h"
>  #include "compression.h"
> +#include "qgroup.h"
>  
>  /* magic values for the inode_only field in btrfs_log_inode:
>   *
> @@ -680,6 +681,21 @@ static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
>  		ins.type = BTRFS_EXTENT_ITEM_KEY;
>  		offset = key->offset - btrfs_file_extent_offset(eb, item);
>  
> +		/*
> +		 * Manually record dirty extent, as here we did a shallow
> +		 * file extent item copy and skip normal backref update,
> +		 * but modifying extent tree all by ourselves.
> +		 * So need to manually record dirty extent for qgroup,
> +		 * as the owner of the file extent changed from log tree
> +		 * (doesn't affect qgroup) to fs/file tree(affects qgroup)
> +		 */
> +		ret = btrfs_qgroup_insert_dirty_extent(trans, root->fs_info,
> +				btrfs_file_extent_disk_bytenr(eb, item),
> +				btrfs_file_extent_disk_num_bytes(eb, item),
> +				GFP_NOFS);
> +		if (ret < 0)
> +			goto out;
> +
>  		if (ins.objectid > 0) {
>  			u64 csum_start;
>  			u64 csum_end;
> 

-- 
Goldwyn

Re: [PATCH v3 2/3] btrfs: relocation: Fix leaking qgroups numbers on data extents

[Filipe Manana]

On Tue, Aug 9, 2016 at 9:30 AM, Qu Wenruo <quwenruo@cn.fujitsu.com> wrote:
> When balancing data extents, qgroup will leak all its numbers for
> relocated data extents.
>
> The relocation is done in the following steps for data extents:
> 1) Create data reloc tree and inode
> 2) Copy all data extents to data reloc tree
>    And commit transaction
> 3) Create tree reloc tree(special snapshot) for any related subvolumes
> 4) Replace file extent in tree reloc tree with new extents in data reloc
>    tree
>    And commit transaction
> 5) Merge tree reloc tree with original fs, by swapping tree blocks
>
> For 1)~4), since tree reloc tree and data reloc tree doesn't count to
> qgroup, everything is OK.
>
> But for 5), the swapping of tree blocks will only info qgroup to track
> metadata extents.
>
> If metadata extents contain file extents, qgroup number for file extents
> will get lost, leading to corrupted qgroup accounting.
>
> The fix is, before commit transaction of step 5), manually info qgroup to
> track all file extents in data reloc tree.
> Since at commit transaction time, the tree swapping is done, and qgroup
> will account these data extents correctly.

Hi Qu,

This changelog should mention this fixes a regression introduced in
the 4.2 kernel.
It's specially important for people responsible to backport fixes to
earlier kernel releases.

>
> Cc: Mark Fasheh <mfasheh@suse.de>
> Reported-by: Mark Fasheh <mfasheh@suse.de>
> Reported-by: Filipe Manana <fdmanana@gmail.com>
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
> ---
>  fs/btrfs/relocation.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 108 insertions(+), 6 deletions(-)
>
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index b26a5ae..a6ace8a 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -31,6 +31,7 @@
>  #include "async-thread.h"
>  #include "free-space-cache.h"
>  #include "inode-map.h"
> +#include "qgroup.h"
>
>  /*
>   * backref_node, mapping_node and tree_block start with this
> @@ -3916,6 +3917,95 @@ int prepare_to_relocate(struct reloc_control *rc)
>         return 0;
>  }
>
> +/*
> + * Qgroup fixer for data chunk relocation.
> + * The data relocation is done in the following steps
> + * 1) Copy data extents into data reloc tree
> + * 2) Create tree reloc tree(special snapshot) for related subvolumes
> + * 3) Modify file extents in tree reloc tree
> + * 4) Merge tree reloc tree with original fs tree, by swapping tree blocks
> + *
> + * The problem is, data and tree reloc tree are not accounted to qgroup,
> + * and 4) will only info qgroup to track tree blocks change, not file extents
> + * in the tree blocks.
> + *
> + * The good news is, related data extents are all in data reloc tree, so we
> + * only need to info qgroup to track all file extents in data reloc tree
> + * before commit trans.
> + */
> +static int qgroup_fix_relocated_data_extents(struct btrfs_trans_handle *trans,
> +                                            struct reloc_control *rc)
> +{
> +       struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
> +       struct inode *inode = rc->data_inode;
> +       struct btrfs_root *data_reloc_root = BTRFS_I(inode)->root;
> +       struct btrfs_path *path;
> +       struct btrfs_key key;
> +       int ret = 0;
> +
> +       if (!fs_info->quota_enabled)
> +               return 0;
> +
> +       /*
> +        * Only for stage where we update data pointers the qgroup fix is
> +        * valid.
> +        * For MOVING_DATA stage, we will miss the timing of swapping tree
> +        * blocks, and won't fix it.
> +        */
> +       if (!(rc->stage == UPDATE_DATA_PTRS && rc->extents_found))
> +               return 0;
> +
> +       path = btrfs_alloc_path();
> +       if (!path)
> +               return -ENOMEM;
> +       key.objectid = btrfs_ino(inode);
> +       key.type = BTRFS_EXTENT_DATA_KEY;
> +       key.offset = 0;
> +
> +       ret = btrfs_search_slot(NULL, data_reloc_root, &key, path, 0, 0);
> +       if (ret < 0)
> +               goto out;
> +
> +       lock_extent(&BTRFS_I(inode)->io_tree, 0, (u64)-1);
> +       while (1) {
> +               struct btrfs_file_extent_item *fi;
> +
> +               btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
> +               if (key.objectid > btrfs_ino(inode))
> +                       break;
> +               if (key.type != BTRFS_EXTENT_DATA_KEY)
> +                       goto next;
> +               fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
> +                                   struct btrfs_file_extent_item);
> +               if (btrfs_file_extent_type(path->nodes[0], fi) !=
> +                               BTRFS_FILE_EXTENT_REG)
> +                       goto next;
> +               /*
> +               pr_info("disk bytenr: %llu, num_bytes: %llu\n",
> +                       btrfs_file_extent_disk_bytenr(path->nodes[0], fi),
> +                       btrfs_file_extent_disk_num_bytes(path->nodes[0], fi));
> +                       */

Please remove this debugging pr_info.

> +               ret = btrfs_qgroup_insert_dirty_extent(trans, fs_info,
> +                       btrfs_file_extent_disk_bytenr(path->nodes[0], fi),
> +                       btrfs_file_extent_disk_num_bytes(path->nodes[0], fi),
> +                       GFP_NOFS);
> +               if (ret < 0)
> +                       break;
> +next:
> +               ret = btrfs_next_item(data_reloc_root, path);
> +               if (ret < 0)
> +                       break;
> +               if (ret > 0) {
> +                       ret = 0;
> +                       break;
> +               }
> +       }
> +       unlock_extent(&BTRFS_I(inode)->io_tree, 0 , (u64)-1);
> +out:
> +       btrfs_free_path(path);
> +       return ret;
> +}
> +
>  static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
>  {
>         struct rb_root blocks = RB_ROOT;
> @@ -4102,10 +4192,16 @@ restart:
>
>         /* get rid of pinned extents */
>         trans = btrfs_join_transaction(rc->extent_root);
> -       if (IS_ERR(trans))
> +       if (IS_ERR(trans)) {
>                 err = PTR_ERR(trans);
> -       else
> -               btrfs_commit_transaction(trans, rc->extent_root);
> +               goto out_free;
> +       }
> +       err = qgroup_fix_relocated_data_extents(trans, rc);
> +       if (err < 0) {
> +               btrfs_abort_transaction(trans, err);
> +               goto out_free;
> +       }
> +       btrfs_commit_transaction(trans, rc->extent_root);
>  out_free:
>         btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
>         btrfs_free_path(path);
> @@ -4468,10 +4564,16 @@ int btrfs_recover_relocation(struct btrfs_root *root)
>         unset_reloc_control(rc);
>
>         trans = btrfs_join_transaction(rc->extent_root);
> -       if (IS_ERR(trans))
> +       if (IS_ERR(trans)) {
>                 err = PTR_ERR(trans);
> -       else
> -               err = btrfs_commit_transaction(trans, rc->extent_root);
> +               goto out_free;
> +       }
> +       err = qgroup_fix_relocated_data_extents(trans, rc);
> +       if (err < 0) {
> +               btrfs_abort_transaction(trans, err);
> +               goto out_free;
> +       }
> +       err = btrfs_commit_transaction(trans, rc->extent_root);
>  out_free:
>         kfree(rc);
>  out:
> --
> 2.9.2
>
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html



-- 
Filipe David Manana,

"People will forget what you said,
 people will forget what you did,
 but people will never forget how you made them feel."

Re: [PATCH v3 2/3] btrfs: relocation: Fix leaking qgroups numbers on data extents

[Qu Wenruo]

At 08/12/2016 09:33 PM, Filipe Manana wrote:
> On Tue, Aug 9, 2016 at 9:30 AM, Qu Wenruo <quwenruo@cn.fujitsu.com> wrote:
>> When balancing data extents, qgroup will leak all its numbers for
>> relocated data extents.
>>
>> The relocation is done in the following steps for data extents:
>> 1) Create data reloc tree and inode
>> 2) Copy all data extents to data reloc tree
>>    And commit transaction
>> 3) Create tree reloc tree(special snapshot) for any related subvolumes
>> 4) Replace file extent in tree reloc tree with new extents in data reloc
>>    tree
>>    And commit transaction
>> 5) Merge tree reloc tree with original fs, by swapping tree blocks
>>
>> For 1)~4), since tree reloc tree and data reloc tree doesn't count to
>> qgroup, everything is OK.
>>
>> But for 5), the swapping of tree blocks will only info qgroup to track
>> metadata extents.
>>
>> If metadata extents contain file extents, qgroup number for file extents
>> will get lost, leading to corrupted qgroup accounting.
>>
>> The fix is, before commit transaction of step 5), manually info qgroup to
>> track all file extents in data reloc tree.
>> Since at commit transaction time, the tree swapping is done, and qgroup
>> will account these data extents correctly.
>
> Hi Qu,
>
> This changelog should mention this fixes a regression introduced in
> the 4.2 kernel.
> It's specially important for people responsible to backport fixes to
> earlier kernel releases.

Thanks, I'll update this patch and remove the pr_info in next version.

Thanks,
Qu
>
>>
>> Cc: Mark Fasheh <mfasheh@suse.de>
>> Reported-by: Mark Fasheh <mfasheh@suse.de>
>> Reported-by: Filipe Manana <fdmanana@gmail.com>
>> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
>> ---
>>  fs/btrfs/relocation.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++---
>>  1 file changed, 108 insertions(+), 6 deletions(-)
>>
>> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
>> index b26a5ae..a6ace8a 100644
>> --- a/fs/btrfs/relocation.c
>> +++ b/fs/btrfs/relocation.c
>> @@ -31,6 +31,7 @@
>>  #include "async-thread.h"
>>  #include "free-space-cache.h"
>>  #include "inode-map.h"
>> +#include "qgroup.h"
>>
>>  /*
>>   * backref_node, mapping_node and tree_block start with this
>> @@ -3916,6 +3917,95 @@ int prepare_to_relocate(struct reloc_control *rc)
>>         return 0;
>>  }
>>
>> +/*
>> + * Qgroup fixer for data chunk relocation.
>> + * The data relocation is done in the following steps
>> + * 1) Copy data extents into data reloc tree
>> + * 2) Create tree reloc tree(special snapshot) for related subvolumes
>> + * 3) Modify file extents in tree reloc tree
>> + * 4) Merge tree reloc tree with original fs tree, by swapping tree blocks
>> + *
>> + * The problem is, data and tree reloc tree are not accounted to qgroup,
>> + * and 4) will only info qgroup to track tree blocks change, not file extents
>> + * in the tree blocks.
>> + *
>> + * The good news is, related data extents are all in data reloc tree, so we
>> + * only need to info qgroup to track all file extents in data reloc tree
>> + * before commit trans.
>> + */
>> +static int qgroup_fix_relocated_data_extents(struct btrfs_trans_handle *trans,
>> +                                            struct reloc_control *rc)
>> +{
>> +       struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
>> +       struct inode *inode = rc->data_inode;
>> +       struct btrfs_root *data_reloc_root = BTRFS_I(inode)->root;
>> +       struct btrfs_path *path;
>> +       struct btrfs_key key;
>> +       int ret = 0;
>> +
>> +       if (!fs_info->quota_enabled)
>> +               return 0;
>> +
>> +       /*
>> +        * Only for stage where we update data pointers the qgroup fix is
>> +        * valid.
>> +        * For MOVING_DATA stage, we will miss the timing of swapping tree
>> +        * blocks, and won't fix it.
>> +        */
>> +       if (!(rc->stage == UPDATE_DATA_PTRS && rc->extents_found))
>> +               return 0;
>> +
>> +       path = btrfs_alloc_path();
>> +       if (!path)
>> +               return -ENOMEM;
>> +       key.objectid = btrfs_ino(inode);
>> +       key.type = BTRFS_EXTENT_DATA_KEY;
>> +       key.offset = 0;
>> +
>> +       ret = btrfs_search_slot(NULL, data_reloc_root, &key, path, 0, 0);
>> +       if (ret < 0)
>> +               goto out;
>> +
>> +       lock_extent(&BTRFS_I(inode)->io_tree, 0, (u64)-1);
>> +       while (1) {
>> +               struct btrfs_file_extent_item *fi;
>> +
>> +               btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
>> +               if (key.objectid > btrfs_ino(inode))
>> +                       break;
>> +               if (key.type != BTRFS_EXTENT_DATA_KEY)
>> +                       goto next;
>> +               fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
>> +                                   struct btrfs_file_extent_item);
>> +               if (btrfs_file_extent_type(path->nodes[0], fi) !=
>> +                               BTRFS_FILE_EXTENT_REG)
>> +                       goto next;
>> +               /*
>> +               pr_info("disk bytenr: %llu, num_bytes: %llu\n",
>> +                       btrfs_file_extent_disk_bytenr(path->nodes[0], fi),
>> +                       btrfs_file_extent_disk_num_bytes(path->nodes[0], fi));
>> +                       */
>
> Please remove this debugging pr_info.
>
>> +               ret = btrfs_qgroup_insert_dirty_extent(trans, fs_info,
>> +                       btrfs_file_extent_disk_bytenr(path->nodes[0], fi),
>> +                       btrfs_file_extent_disk_num_bytes(path->nodes[0], fi),
>> +                       GFP_NOFS);
>> +               if (ret < 0)
>> +                       break;
>> +next:
>> +               ret = btrfs_next_item(data_reloc_root, path);
>> +               if (ret < 0)
>> +                       break;
>> +               if (ret > 0) {
>> +                       ret = 0;
>> +                       break;
>> +               }
>> +       }
>> +       unlock_extent(&BTRFS_I(inode)->io_tree, 0 , (u64)-1);
>> +out:
>> +       btrfs_free_path(path);
>> +       return ret;
>> +}
>> +
>>  static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
>>  {
>>         struct rb_root blocks = RB_ROOT;
>> @@ -4102,10 +4192,16 @@ restart:
>>
>>         /* get rid of pinned extents */
>>         trans = btrfs_join_transaction(rc->extent_root);
>> -       if (IS_ERR(trans))
>> +       if (IS_ERR(trans)) {
>>                 err = PTR_ERR(trans);
>> -       else
>> -               btrfs_commit_transaction(trans, rc->extent_root);
>> +               goto out_free;
>> +       }
>> +       err = qgroup_fix_relocated_data_extents(trans, rc);
>> +       if (err < 0) {
>> +               btrfs_abort_transaction(trans, err);
>> +               goto out_free;
>> +       }
>> +       btrfs_commit_transaction(trans, rc->extent_root);
>>  out_free:
>>         btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
>>         btrfs_free_path(path);
>> @@ -4468,10 +4564,16 @@ int btrfs_recover_relocation(struct btrfs_root *root)
>>         unset_reloc_control(rc);
>>
>>         trans = btrfs_join_transaction(rc->extent_root);
>> -       if (IS_ERR(trans))
>> +       if (IS_ERR(trans)) {
>>                 err = PTR_ERR(trans);
>> -       else
>> -               err = btrfs_commit_transaction(trans, rc->extent_root);
>> +               goto out_free;
>> +       }
>> +       err = qgroup_fix_relocated_data_extents(trans, rc);
>> +       if (err < 0) {
>> +               btrfs_abort_transaction(trans, err);
>> +               goto out_free;
>> +       }
>> +       err = btrfs_commit_transaction(trans, rc->extent_root);
>>  out_free:
>>         kfree(rc);
>>  out:
>> --
>> 2.9.2
>>
>>
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>
>