Re: FAILED: patch "[PATCH] Btrfs: fix regression running delayed references when using" failed to apply to 4.2-stable tree

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On 12/12/2015 10:02 PM, Filipe Manana wrote:
> 
> 
> On 12/12/2015 09:43 PM, Greg KH wrote:
>> On Sat, Dec 12, 2015 at 09:35:45PM +0000, Filipe Manana wrote:
>>>
>>>
>>> On 12/12/2015 08:03 PM, Greg KH wrote:
>>>> On Sat, Dec 12, 2015 at 11:57:49AM -0800, Greg KH wrote:
>>>>> On Sat, Dec 12, 2015 at 02:32:10PM +0000, Filipe Manana wrote:
>>>>>>
>>>>>>
>>>>>> On 12/11/2015 04:54 PM, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
>>>>>>>
>>>>>>> The patch below does not apply to the 4.2-stable tree.
>>>>>>> If someone wants it applied there, or to any other stable or longterm
>>>>>>> tree, then please email the backport, including the original git commit
>>>>>>> id to <stable@xxxxxxxxxxxxxxx>.
>>>>>>
>>>>>> Greg, please find attached a version of the patch that applies against
>>>>>> 4.2.7.
>>>>>
>>>>> This patch breaks the build:
>>>
>>> I did build and tested it (in reply to your next comment about sending
>>> untested stuff).
>>> See comment inlined below.
>>>
>>>>>
>>>>> fs/btrfs/delayed-ref.c: In function ‘merge_ref’:
>>>>> fs/btrfs/delayed-ref.c:223:38: error: ‘struct btrfs_delayed_ref_node’ has no mem
>>>>> ber named ‘no_quota’
>>>>>    if (next->type != ref->type || next->no_quota != ref->no_quota)
>>>
>>> I don't get why you're getting that error.
>>> struct btrfs_delayed_ref_node has a member named 'no_quota':
>>>
>>> https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/fs/btrfs/delayed-ref.h?id=refs/tags/v4.2.7#n36
>>>
>>> https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/fs/btrfs/delayed-ref.h?id=refs/tags/v4.2.7#n71
>>>
>>> Am I missing something?
>>>
>>> I think you applied 2 patches in the wrong order. You should apply the
>>> following two in this order:
>>>
>>> 1) "Btrfs: fix regression when running delayed references" -
>>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=2c3cf7d5f6105bb957df125dfce61d4483b8742d
>>>
>>> 2) "Btrfs: fix regression running delayed references when using qgroups"
>>> -
>>> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b06c4bf5c874a57254b197f53ddf588e7a24a2bf
>>>
>>> Please confirm if you applied those 2 in that specific order, because it
>>> doesn't seem so. The first one adds code that still uses member
>>> "no_quota" while the second one removes the "no_quota" member from that
>>> struct.
>>
>> You only sent me one patch, one for both trees.  I built the tree after
>> applying what I had from you.
>>
>> If you need/want me to apply 2 patches, please send both of them, can
>> you do so for the -rc kernels I just released?
> 
> I didn't send both patches because for the first one there wasn't any
> complain about it not applying cleanly to the 4.2 and 4.3 trees. So I
> only sent the second one, since that was the only one that didn't apply
> cleanly.
> 
> Ok, I'll do it again, based on those rcs, and send you both patches for
> both stable releases. Where are those rc branches?
> 
> thanks

Ok, here are (as attachments) the 2 patches for 4.2 and 4.3 that should
apply cleanly against what's in your queues. The file names reflect the
release and order:

0001-4.2.7-Btrfs-fix-regression-when-running-delayed-references.patch
0001-4.3.2-Btrfs-fix-regression-when-running-delayed-references.patch
0002-4.2.7-Btrfs-fix-regression-running-delayed-references-when.patch
0002-4.3.2-Btrfs-fix-regression-running-delayed-references-when.patch

Thanks

> 
>>
>> thanks,
>>
>> greg k-h
>>
>From 61457e03e560309aad245d9cd5b3862521d5c1a2 Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana@xxxxxxxx>
Date: Thu, 22 Oct 2015 09:47:34 +0100
Subject: [PATCH 1/2] Btrfs: fix regression when running delayed references
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit 2c3cf7d5f6105bb957df125dfce61d4483b8742d upstream.

In the kernel 4.2 merge window we had a refactoring/rework of the delayed
references implementation in order to fix certain problems with qgroups.
However that rework introduced one more regression that leads to the
following trace when running delayed references for metadata:

[35908.064664] kernel BUG at fs/btrfs/extent-tree.c:1832!
[35908.065201] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[35908.065201] Modules linked in: dm_flakey dm_mod btrfs crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse parport_pc psmouse i2
[35908.065201] CPU: 14 PID: 15014 Comm: kworker/u32:9 Tainted: G        W       4.3.0-rc5-btrfs-next-17+ #1
[35908.065201] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014
[35908.065201] Workqueue: btrfs-extent-refs btrfs_extent_refs_helper [btrfs]
[35908.065201] task: ffff880114b7d780 ti: ffff88010c4c8000 task.ti: ffff88010c4c8000
[35908.065201] RIP: 0010:[<ffffffffa04928b5>]  [<ffffffffa04928b5>] insert_inline_extent_backref+0x52/0xb1 [btrfs]
[35908.065201] RSP: 0018:ffff88010c4cbb08  EFLAGS: 00010293
[35908.065201] RAX: 0000000000000000 RBX: ffff88008a661000 RCX: 0000000000000000
[35908.065201] RDX: ffffffffa04dd58f RSI: 0000000000000001 RDI: 0000000000000000
[35908.065201] RBP: ffff88010c4cbb40 R08: 0000000000001000 R09: ffff88010c4cb9f8
[35908.065201] R10: 0000000000000000 R11: 000000000000002c R12: 0000000000000000
[35908.065201] R13: ffff88020a74c578 R14: 0000000000000000 R15: 0000000000000000
[35908.065201] FS:  0000000000000000(0000) GS:ffff88023edc0000(0000) knlGS:0000000000000000
[35908.065201] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[35908.065201] CR2: 00000000015e8708 CR3: 0000000102185000 CR4: 00000000000006e0
[35908.065201] Stack:
[35908.065201]  ffff88010c4cbb18 0000000000000f37 ffff88020a74c578 ffff88015a408000
[35908.065201]  ffff880154a44000 0000000000000000 0000000000000005 ffff88010c4cbbd8
[35908.065201]  ffffffffa0492b9a 0000000000000005 0000000000000000 0000000000000000
[35908.065201] Call Trace:
[35908.065201]  [<ffffffffa0492b9a>] __btrfs_inc_extent_ref+0x8b/0x208 [btrfs]
[35908.065201]  [<ffffffffa0497117>] ? __btrfs_run_delayed_refs+0x4d4/0xd33 [btrfs]
[35908.065201]  [<ffffffffa049773d>] __btrfs_run_delayed_refs+0xafa/0xd33 [btrfs]
[35908.065201]  [<ffffffffa04a976a>] ? join_transaction.isra.10+0x25/0x41f [btrfs]
[35908.065201]  [<ffffffffa04a97ed>] ? join_transaction.isra.10+0xa8/0x41f [btrfs]
[35908.065201]  [<ffffffffa049914d>] btrfs_run_delayed_refs+0x75/0x1dd [btrfs]
[35908.065201]  [<ffffffffa04992f1>] delayed_ref_async_start+0x3c/0x7b [btrfs]
[35908.065201]  [<ffffffffa04d4b4f>] normal_work_helper+0x14c/0x32a [btrfs]
[35908.065201]  [<ffffffffa04d4e93>] btrfs_extent_refs_helper+0x12/0x14 [btrfs]
[35908.065201]  [<ffffffff81063b23>] process_one_work+0x24a/0x4ac
[35908.065201]  [<ffffffff81064285>] worker_thread+0x206/0x2c2
[35908.065201]  [<ffffffff8106407f>] ? rescuer_thread+0x2cb/0x2cb
[35908.065201]  [<ffffffff8106407f>] ? rescuer_thread+0x2cb/0x2cb
[35908.065201]  [<ffffffff8106904d>] kthread+0xef/0xf7
[35908.065201]  [<ffffffff81068f5e>] ? kthread_parkme+0x24/0x24
[35908.065201]  [<ffffffff8147d10f>] ret_from_fork+0x3f/0x70
[35908.065201]  [<ffffffff81068f5e>] ? kthread_parkme+0x24/0x24
[35908.065201] Code: 6a 01 41 56 41 54 ff 75 10 41 51 4d 89 c1 49 89 c8 48 8d 4d d0 e8 f6 f1 ff ff 48 83 c4 28 85 c0 75 2c 49 81 fc ff 00 00 00 77 02 <0f> 0b 4c 8b 45 30 8b 4d 28 45 31
[35908.065201] RIP  [<ffffffffa04928b5>] insert_inline_extent_backref+0x52/0xb1 [btrfs]
[35908.065201]  RSP <ffff88010c4cbb08>
[35908.310885] ---[ end trace fe4299baf0666457 ]---

This happens because the new delayed references code no longer merges
delayed references that have different sequence values. The following
steps are an example sequence leading to this issue:

1) Transaction N starts, fs_info->tree_mod_seq has value 0;

2) Extent buffer (btree node) A is allocated, delayed reference Ref1 for
   bytenr A is created, with a value of 1 and a seq value of 0;

3) fs_info->tree_mod_seq is incremented to 1;

4) Extent buffer A is deleted through btrfs_del_items(), which calls
   btrfs_del_leaf(), which in turn calls btrfs_free_tree_block(). The
   later returns the metadata extent associated to extent buffer A to
   the free space cache (the range is not pinned), because the extent
   buffer was created in the current transaction (N) and writeback never
   happened for the extent buffer (flag BTRFS_HEADER_FLAG_WRITTEN not set
   in the extent buffer).
   This creates the delayed reference Ref2 for bytenr A, with a value
   of -1 and a seq value of 1;

5) Delayed reference Ref2 is not merged with Ref1 when we create it,
   because they have different sequence numbers (decided at
   add_delayed_ref_tail_merge());

6) fs_info->tree_mod_seq is incremented to 2;

7) Some task attempts to allocate a new extent buffer (done at
   extent-tree.c:find_free_extent()), but due to heavy fragmentation
   and running low on metadata space the clustered allocation fails
   and we fall back to unclustered allocation, which finds the
   extent at offset A, so a new extent buffer at offset A is allocated.
   This creates delayed reference Ref3 for bytenr A, with a value of 1
   and a seq value of 2;

8) Ref3 is not merged neither with Ref2 nor Ref1, again because they
   all have different seq values;

9) We start running the delayed references (__btrfs_run_delayed_refs());

10) The delayed Ref1 is the first one being applied, which ends up
    creating an inline extent backref in the extent tree;

10) Next the delayed reference Ref3 is selected for execution, and not
    Ref2, because select_delayed_ref() always gives a preference for
    positive references (that have an action of BTRFS_ADD_DELAYED_REF);

11) When running Ref3 we encounter alreay the inline extent backref
    in the extent tree at insert_inline_extent_backref(), which makes
    us hit the following BUG_ON:

        BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);

    This is always true because owner corresponds to the level of the
    extent buffer/btree node in the btree.

For the scenario described above we hit the BUG_ON because we never merge
references that have different seq values.

We used to do the merging before the 4.2 kernel, more specifically, before
the commmits:

  c6fc24549960 ("btrfs: delayed-ref: Use list to replace the ref_root in ref_head.")
  c43d160fcd5e ("btrfs: delayed-ref: Cleanup the unneeded functions.")

This issue became more exposed after the following change that was added
to 4.2 as well:

  cffc3374e567 ("Btrfs: fix order by which delayed references are run")

Which in turn fixed another regression by the two commits previously
mentioned.

So fix this by bringing back the delayed reference merge code, with the
proper adaptations so that it operates against the new data structure
(linked list vs old red black tree implementation).

This issue was hit running fstest btrfs/063 in a loop. Several people have
reported this issue in the mailing list when running on kernels 4.2+.

Very special thanks to Stéphane Lesimple for helping debugging this issue
and testing this fix on his multi terabyte filesystem (which took more
than one day to balance alone, plus fsck, etc).

Fixes: c6fc24549960 ("btrfs: delayed-ref: Use list to replace the ref_root in ref_head.")
Reported-by: Peter Becker <floyd.net@xxxxxxxxx>
Reported-by: Stéphane Lesimple <stephane_btrfs@xxxxxxxxxxx>
Tested-by: Stéphane Lesimple <stephane_btrfs@xxxxxxxxxxx>
Reported-by: Malte Schröder <malte@xxxxxxxx>
Reported-by: Derek Dongray <derek@xxxxxxxxxxxxx>
Reported-by: Erkki Seppala <flux-btrfs@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx  # 4.2+
Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Reviewed-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
---
 fs/btrfs/delayed-ref.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/extent-tree.c |  14 ++++++
 2 files changed, 127 insertions(+)

diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index ac3e81d..4832943 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -197,6 +197,119 @@ static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
 		trans->delayed_ref_updates--;
 }
 
+static bool merge_ref(struct btrfs_trans_handle *trans,
+		      struct btrfs_delayed_ref_root *delayed_refs,
+		      struct btrfs_delayed_ref_head *head,
+		      struct btrfs_delayed_ref_node *ref,
+		      u64 seq)
+{
+	struct btrfs_delayed_ref_node *next;
+	bool done = false;
+
+	next = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
+				list);
+	while (!done && &next->list != &head->ref_list) {
+		int mod;
+		struct btrfs_delayed_ref_node *next2;
+
+		next2 = list_next_entry(next, list);
+
+		if (next == ref)
+			goto next;
+
+		if (seq && next->seq >= seq)
+			goto next;
+
+		if (next->type != ref->type || next->no_quota != ref->no_quota)
+			goto next;
+
+		if ((ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
+		     ref->type == BTRFS_SHARED_BLOCK_REF_KEY) &&
+		    comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref),
+				   btrfs_delayed_node_to_tree_ref(next),
+				   ref->type))
+			goto next;
+		if ((ref->type == BTRFS_EXTENT_DATA_REF_KEY ||
+		     ref->type == BTRFS_SHARED_DATA_REF_KEY) &&
+		    comp_data_refs(btrfs_delayed_node_to_data_ref(ref),
+				   btrfs_delayed_node_to_data_ref(next)))
+			goto next;
+
+		if (ref->action == next->action) {
+			mod = next->ref_mod;
+		} else {
+			if (ref->ref_mod < next->ref_mod) {
+				swap(ref, next);
+				done = true;
+			}
+			mod = -next->ref_mod;
+		}
+
+		drop_delayed_ref(trans, delayed_refs, head, next);
+		ref->ref_mod += mod;
+		if (ref->ref_mod == 0) {
+			drop_delayed_ref(trans, delayed_refs, head, ref);
+			done = true;
+		} else {
+			/*
+			 * Can't have multiples of the same ref on a tree block.
+			 */
+			WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
+				ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
+		}
+next:
+		next = next2;
+	}
+
+	return done;
+}
+
+void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
+			      struct btrfs_fs_info *fs_info,
+			      struct btrfs_delayed_ref_root *delayed_refs,
+			      struct btrfs_delayed_ref_head *head)
+{
+	struct btrfs_delayed_ref_node *ref;
+	u64 seq = 0;
+
+	assert_spin_locked(&head->lock);
+
+	if (list_empty(&head->ref_list))
+		return;
+
+	/* We don't have too many refs to merge for data. */
+	if (head->is_data)
+		return;
+
+	spin_lock(&fs_info->tree_mod_seq_lock);
+	if (!list_empty(&fs_info->tree_mod_seq_list)) {
+		struct seq_list *elem;
+
+		elem = list_first_entry(&fs_info->tree_mod_seq_list,
+					struct seq_list, list);
+		seq = elem->seq;
+	}
+	spin_unlock(&fs_info->tree_mod_seq_lock);
+
+	ref = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
+			       list);
+	while (&ref->list != &head->ref_list) {
+		if (seq && ref->seq >= seq)
+			goto next;
+
+		if (merge_ref(trans, delayed_refs, head, ref, seq)) {
+			if (list_empty(&head->ref_list))
+				break;
+			ref = list_first_entry(&head->ref_list,
+					       struct btrfs_delayed_ref_node,
+					       list);
+			continue;
+		}
+next:
+		ref = list_next_entry(ref, list);
+	}
+}
+
 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
 			    struct btrfs_delayed_ref_root *delayed_refs,
 			    u64 seq)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 07204bf..a66f59a 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2365,7 +2365,21 @@ static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
 			}
 		}
 
+		/*
+		 * We need to try and merge add/drops of the same ref since we
+		 * can run into issues with relocate dropping the implicit ref
+		 * and then it being added back again before the drop can
+		 * finish.  If we merged anything we need to re-loop so we can
+		 * get a good ref.
+		 * Or we can get node references of the same type that weren't
+		 * merged when created due to bumps in the tree mod seq, and
+		 * we need to merge them to prevent adding an inline extent
+		 * backref before dropping it (triggering a BUG_ON at
+		 * insert_inline_extent_backref()).
+		 */
 		spin_lock(&locked_ref->lock);
+		btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
+					 locked_ref);
 
 		/*
 		 * locked_ref is the head node, so we have to go one
-- 
2.1.3

>From e804af74715e3ad5c237e6a79f4a1b69b198b52f Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana@xxxxxxxx>
Date: Thu, 22 Oct 2015 09:47:34 +0100
Subject: [PATCH 1/2] Btrfs: fix regression when running delayed references
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit 2c3cf7d5f6105bb957df125dfce61d4483b8742d upstream.

In the kernel 4.2 merge window we had a refactoring/rework of the delayed
references implementation in order to fix certain problems with qgroups.
However that rework introduced one more regression that leads to the
following trace when running delayed references for metadata:

[35908.064664] kernel BUG at fs/btrfs/extent-tree.c:1832!
[35908.065201] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[35908.065201] Modules linked in: dm_flakey dm_mod btrfs crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse parport_pc psmouse i2
[35908.065201] CPU: 14 PID: 15014 Comm: kworker/u32:9 Tainted: G        W       4.3.0-rc5-btrfs-next-17+ #1
[35908.065201] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014
[35908.065201] Workqueue: btrfs-extent-refs btrfs_extent_refs_helper [btrfs]
[35908.065201] task: ffff880114b7d780 ti: ffff88010c4c8000 task.ti: ffff88010c4c8000
[35908.065201] RIP: 0010:[<ffffffffa04928b5>]  [<ffffffffa04928b5>] insert_inline_extent_backref+0x52/0xb1 [btrfs]
[35908.065201] RSP: 0018:ffff88010c4cbb08  EFLAGS: 00010293
[35908.065201] RAX: 0000000000000000 RBX: ffff88008a661000 RCX: 0000000000000000
[35908.065201] RDX: ffffffffa04dd58f RSI: 0000000000000001 RDI: 0000000000000000
[35908.065201] RBP: ffff88010c4cbb40 R08: 0000000000001000 R09: ffff88010c4cb9f8
[35908.065201] R10: 0000000000000000 R11: 000000000000002c R12: 0000000000000000
[35908.065201] R13: ffff88020a74c578 R14: 0000000000000000 R15: 0000000000000000
[35908.065201] FS:  0000000000000000(0000) GS:ffff88023edc0000(0000) knlGS:0000000000000000
[35908.065201] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[35908.065201] CR2: 00000000015e8708 CR3: 0000000102185000 CR4: 00000000000006e0
[35908.065201] Stack:
[35908.065201]  ffff88010c4cbb18 0000000000000f37 ffff88020a74c578 ffff88015a408000
[35908.065201]  ffff880154a44000 0000000000000000 0000000000000005 ffff88010c4cbbd8
[35908.065201]  ffffffffa0492b9a 0000000000000005 0000000000000000 0000000000000000
[35908.065201] Call Trace:
[35908.065201]  [<ffffffffa0492b9a>] __btrfs_inc_extent_ref+0x8b/0x208 [btrfs]
[35908.065201]  [<ffffffffa0497117>] ? __btrfs_run_delayed_refs+0x4d4/0xd33 [btrfs]
[35908.065201]  [<ffffffffa049773d>] __btrfs_run_delayed_refs+0xafa/0xd33 [btrfs]
[35908.065201]  [<ffffffffa04a976a>] ? join_transaction.isra.10+0x25/0x41f [btrfs]
[35908.065201]  [<ffffffffa04a97ed>] ? join_transaction.isra.10+0xa8/0x41f [btrfs]
[35908.065201]  [<ffffffffa049914d>] btrfs_run_delayed_refs+0x75/0x1dd [btrfs]
[35908.065201]  [<ffffffffa04992f1>] delayed_ref_async_start+0x3c/0x7b [btrfs]
[35908.065201]  [<ffffffffa04d4b4f>] normal_work_helper+0x14c/0x32a [btrfs]
[35908.065201]  [<ffffffffa04d4e93>] btrfs_extent_refs_helper+0x12/0x14 [btrfs]
[35908.065201]  [<ffffffff81063b23>] process_one_work+0x24a/0x4ac
[35908.065201]  [<ffffffff81064285>] worker_thread+0x206/0x2c2
[35908.065201]  [<ffffffff8106407f>] ? rescuer_thread+0x2cb/0x2cb
[35908.065201]  [<ffffffff8106407f>] ? rescuer_thread+0x2cb/0x2cb
[35908.065201]  [<ffffffff8106904d>] kthread+0xef/0xf7
[35908.065201]  [<ffffffff81068f5e>] ? kthread_parkme+0x24/0x24
[35908.065201]  [<ffffffff8147d10f>] ret_from_fork+0x3f/0x70
[35908.065201]  [<ffffffff81068f5e>] ? kthread_parkme+0x24/0x24
[35908.065201] Code: 6a 01 41 56 41 54 ff 75 10 41 51 4d 89 c1 49 89 c8 48 8d 4d d0 e8 f6 f1 ff ff 48 83 c4 28 85 c0 75 2c 49 81 fc ff 00 00 00 77 02 <0f> 0b 4c 8b 45 30 8b 4d 28 45 31
[35908.065201] RIP  [<ffffffffa04928b5>] insert_inline_extent_backref+0x52/0xb1 [btrfs]
[35908.065201]  RSP <ffff88010c4cbb08>
[35908.310885] ---[ end trace fe4299baf0666457 ]---

This happens because the new delayed references code no longer merges
delayed references that have different sequence values. The following
steps are an example sequence leading to this issue:

1) Transaction N starts, fs_info->tree_mod_seq has value 0;

2) Extent buffer (btree node) A is allocated, delayed reference Ref1 for
   bytenr A is created, with a value of 1 and a seq value of 0;

3) fs_info->tree_mod_seq is incremented to 1;

4) Extent buffer A is deleted through btrfs_del_items(), which calls
   btrfs_del_leaf(), which in turn calls btrfs_free_tree_block(). The
   later returns the metadata extent associated to extent buffer A to
   the free space cache (the range is not pinned), because the extent
   buffer was created in the current transaction (N) and writeback never
   happened for the extent buffer (flag BTRFS_HEADER_FLAG_WRITTEN not set
   in the extent buffer).
   This creates the delayed reference Ref2 for bytenr A, with a value
   of -1 and a seq value of 1;

5) Delayed reference Ref2 is not merged with Ref1 when we create it,
   because they have different sequence numbers (decided at
   add_delayed_ref_tail_merge());

6) fs_info->tree_mod_seq is incremented to 2;

7) Some task attempts to allocate a new extent buffer (done at
   extent-tree.c:find_free_extent()), but due to heavy fragmentation
   and running low on metadata space the clustered allocation fails
   and we fall back to unclustered allocation, which finds the
   extent at offset A, so a new extent buffer at offset A is allocated.
   This creates delayed reference Ref3 for bytenr A, with a value of 1
   and a seq value of 2;

8) Ref3 is not merged neither with Ref2 nor Ref1, again because they
   all have different seq values;

9) We start running the delayed references (__btrfs_run_delayed_refs());

10) The delayed Ref1 is the first one being applied, which ends up
    creating an inline extent backref in the extent tree;

10) Next the delayed reference Ref3 is selected for execution, and not
    Ref2, because select_delayed_ref() always gives a preference for
    positive references (that have an action of BTRFS_ADD_DELAYED_REF);

11) When running Ref3 we encounter alreay the inline extent backref
    in the extent tree at insert_inline_extent_backref(), which makes
    us hit the following BUG_ON:

        BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);

    This is always true because owner corresponds to the level of the
    extent buffer/btree node in the btree.

For the scenario described above we hit the BUG_ON because we never merge
references that have different seq values.

We used to do the merging before the 4.2 kernel, more specifically, before
the commmits:

  c6fc24549960 ("btrfs: delayed-ref: Use list to replace the ref_root in ref_head.")
  c43d160fcd5e ("btrfs: delayed-ref: Cleanup the unneeded functions.")

This issue became more exposed after the following change that was added
to 4.2 as well:

  cffc3374e567 ("Btrfs: fix order by which delayed references are run")

Which in turn fixed another regression by the two commits previously
mentioned.

So fix this by bringing back the delayed reference merge code, with the
proper adaptations so that it operates against the new data structure
(linked list vs old red black tree implementation).

This issue was hit running fstest btrfs/063 in a loop. Several people have
reported this issue in the mailing list when running on kernels 4.2+.

Very special thanks to Stéphane Lesimple for helping debugging this issue
and testing this fix on his multi terabyte filesystem (which took more
than one day to balance alone, plus fsck, etc).

Fixes: c6fc24549960 ("btrfs: delayed-ref: Use list to replace the ref_root in ref_head.")
Reported-by: Peter Becker <floyd.net@xxxxxxxxx>
Reported-by: Stéphane Lesimple <stephane_btrfs@xxxxxxxxxxx>
Tested-by: Stéphane Lesimple <stephane_btrfs@xxxxxxxxxxx>
Reported-by: Malte Schröder <malte@xxxxxxxx>
Reported-by: Derek Dongray <derek@xxxxxxxxxxxxx>
Reported-by: Erkki Seppala <flux-btrfs@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx  # 4.2+
Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Reviewed-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
---
 fs/btrfs/delayed-ref.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/extent-tree.c |  14 ++++++
 2 files changed, 127 insertions(+)

diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index ac3e81d..4832943 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -197,6 +197,119 @@ static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
 		trans->delayed_ref_updates--;
 }
 
+static bool merge_ref(struct btrfs_trans_handle *trans,
+		      struct btrfs_delayed_ref_root *delayed_refs,
+		      struct btrfs_delayed_ref_head *head,
+		      struct btrfs_delayed_ref_node *ref,
+		      u64 seq)
+{
+	struct btrfs_delayed_ref_node *next;
+	bool done = false;
+
+	next = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
+				list);
+	while (!done && &next->list != &head->ref_list) {
+		int mod;
+		struct btrfs_delayed_ref_node *next2;
+
+		next2 = list_next_entry(next, list);
+
+		if (next == ref)
+			goto next;
+
+		if (seq && next->seq >= seq)
+			goto next;
+
+		if (next->type != ref->type || next->no_quota != ref->no_quota)
+			goto next;
+
+		if ((ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
+		     ref->type == BTRFS_SHARED_BLOCK_REF_KEY) &&
+		    comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref),
+				   btrfs_delayed_node_to_tree_ref(next),
+				   ref->type))
+			goto next;
+		if ((ref->type == BTRFS_EXTENT_DATA_REF_KEY ||
+		     ref->type == BTRFS_SHARED_DATA_REF_KEY) &&
+		    comp_data_refs(btrfs_delayed_node_to_data_ref(ref),
+				   btrfs_delayed_node_to_data_ref(next)))
+			goto next;
+
+		if (ref->action == next->action) {
+			mod = next->ref_mod;
+		} else {
+			if (ref->ref_mod < next->ref_mod) {
+				swap(ref, next);
+				done = true;
+			}
+			mod = -next->ref_mod;
+		}
+
+		drop_delayed_ref(trans, delayed_refs, head, next);
+		ref->ref_mod += mod;
+		if (ref->ref_mod == 0) {
+			drop_delayed_ref(trans, delayed_refs, head, ref);
+			done = true;
+		} else {
+			/*
+			 * Can't have multiples of the same ref on a tree block.
+			 */
+			WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
+				ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
+		}
+next:
+		next = next2;
+	}
+
+	return done;
+}
+
+void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
+			      struct btrfs_fs_info *fs_info,
+			      struct btrfs_delayed_ref_root *delayed_refs,
+			      struct btrfs_delayed_ref_head *head)
+{
+	struct btrfs_delayed_ref_node *ref;
+	u64 seq = 0;
+
+	assert_spin_locked(&head->lock);
+
+	if (list_empty(&head->ref_list))
+		return;
+
+	/* We don't have too many refs to merge for data. */
+	if (head->is_data)
+		return;
+
+	spin_lock(&fs_info->tree_mod_seq_lock);
+	if (!list_empty(&fs_info->tree_mod_seq_list)) {
+		struct seq_list *elem;
+
+		elem = list_first_entry(&fs_info->tree_mod_seq_list,
+					struct seq_list, list);
+		seq = elem->seq;
+	}
+	spin_unlock(&fs_info->tree_mod_seq_lock);
+
+	ref = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
+			       list);
+	while (&ref->list != &head->ref_list) {
+		if (seq && ref->seq >= seq)
+			goto next;
+
+		if (merge_ref(trans, delayed_refs, head, ref, seq)) {
+			if (list_empty(&head->ref_list))
+				break;
+			ref = list_first_entry(&head->ref_list,
+					       struct btrfs_delayed_ref_node,
+					       list);
+			continue;
+		}
+next:
+		ref = list_next_entry(ref, list);
+	}
+}
+
 int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info,
 			    struct btrfs_delayed_ref_root *delayed_refs,
 			    u64 seq)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 601d7d4..00158bf 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2433,7 +2433,21 @@ static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
 			}
 		}
 
+		/*
+		 * We need to try and merge add/drops of the same ref since we
+		 * can run into issues with relocate dropping the implicit ref
+		 * and then it being added back again before the drop can
+		 * finish.  If we merged anything we need to re-loop so we can
+		 * get a good ref.
+		 * Or we can get node references of the same type that weren't
+		 * merged when created due to bumps in the tree mod seq, and
+		 * we need to merge them to prevent adding an inline extent
+		 * backref before dropping it (triggering a BUG_ON at
+		 * insert_inline_extent_backref()).
+		 */
 		spin_lock(&locked_ref->lock);
+		btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
+					 locked_ref);
 
 		/*
 		 * locked_ref is the head node, so we have to go one
-- 
2.1.3

>From c03ab56d4f89891bbe8f5c609c9f55b5924f90dd Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana@xxxxxxxx>
Date: Fri, 23 Oct 2015 07:52:54 +0100
Subject: [PATCH 2/2] Btrfs: fix regression running delayed references when
 using qgroups
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit b06c4bf5c874a57254b197f53ddf588e7a24a2bf upstream.

In the kernel 4.2 merge window we had a big changes to the implementation
of delayed references and qgroups which made the no_quota field of delayed
references not used anymore. More specifically the no_quota field is not
used anymore as of:

  commit 0ed4792af0e8 ("btrfs: qgroup: Switch to new extent-oriented qgroup mechanism.")

Leaving the no_quota field actually prevents delayed references from
getting merged, which in turn cause the following BUG_ON(), at
fs/btrfs/extent-tree.c, to be hit when qgroups are enabled:

  static int run_delayed_tree_ref(...)
  {
     (...)
     BUG_ON(node->ref_mod != 1);
     (...)
  }

This happens on a scenario like the following:

  1) Ref1 bytenr X, action = BTRFS_ADD_DELAYED_REF, no_quota = 1, added.

  2) Ref2 bytenr X, action = BTRFS_DROP_DELAYED_REF, no_quota = 0, added.
     It's not merged with Ref1 because Ref1->no_quota != Ref2->no_quota.

  3) Ref3 bytenr X, action = BTRFS_ADD_DELAYED_REF, no_quota = 1, added.
     It's not merged with the reference at the tail of the list of refs
     for bytenr X because the reference at the tail, Ref2 is incompatible
     due to Ref2->no_quota != Ref3->no_quota.

  4) Ref4 bytenr X, action = BTRFS_DROP_DELAYED_REF, no_quota = 0, added.
     It's not merged with the reference at the tail of the list of refs
     for bytenr X because the reference at the tail, Ref3 is incompatible
     due to Ref3->no_quota != Ref4->no_quota.

  5) We run delayed references, trigger merging of delayed references,
     through __btrfs_run_delayed_refs() -> btrfs_merge_delayed_refs().

  6) Ref1 and Ref3 are merged as Ref1->no_quota = Ref3->no_quota and
     all other conditions are satisfied too. So Ref1 gets a ref_mod
     value of 2.

  7) Ref2 and Ref4 are merged as Ref2->no_quota = Ref4->no_quota and
     all other conditions are satisfied too. So Ref2 gets a ref_mod
     value of 2.

  8) Ref1 and Ref2 aren't merged, because they have different values
     for their no_quota field.

  9) Delayed reference Ref1 is picked for running (select_delayed_ref()
     always prefers references with an action == BTRFS_ADD_DELAYED_REF).
     So run_delayed_tree_ref() is called for Ref1 which triggers the
     BUG_ON because Ref1->red_mod != 1 (equals 2).

So fix this by removing the no_quota field, as it's not used anymore as
of commit 0ed4792af0e8 ("btrfs: qgroup: Switch to new extent-oriented
qgroup mechanism.").

The use of no_quota was also buggy in at least two places:

1) At delayed-refs.c:btrfs_add_delayed_tree_ref() - we were setting
   no_quota to 0 instead of 1 when the following condition was true:
   is_fstree(ref_root) || !fs_info->quota_enabled

2) At extent-tree.c:__btrfs_inc_extent_ref() - we were attempting to
   reset a node's no_quota when the condition "!is_fstree(root_objectid)
   || !root->fs_info->quota_enabled" was true but we did it only in
   an unused local stack variable, that is, we never reset the no_quota
   value in the node itself.

This fixes the remainder of problems several people have been having when
running delayed references, mostly while a balance is running in parallel,
on a 4.2+ kernel.

Very special thanks to Stéphane Lesimple for helping debugging this issue
and testing this fix on his multi terabyte filesystem (which took more
than one day to balance alone, plus fsck, etc).

Also, this fixes deadlock issue when using the clone ioctl with qgroups
enabled, as reported by Elias Probst in the mailing list. The deadlock
happens because after calling btrfs_insert_empty_item we have our path
holding a write lock on a leaf of the fs/subvol tree and then before
releasing the path we called check_ref() which did backref walking, when
qgroups are enabled, and tried to read lock the same leaf. The trace for
this case is the following:

  INFO: task systemd-nspawn:6095 blocked for more than 120 seconds.
  (...)
  Call Trace:
    [<ffffffff86999201>] schedule+0x74/0x83
    [<ffffffff863ef64c>] btrfs_tree_read_lock+0xc0/0xea
    [<ffffffff86137ed7>] ? wait_woken+0x74/0x74
    [<ffffffff8639f0a7>] btrfs_search_old_slot+0x51a/0x810
    [<ffffffff863a129b>] btrfs_next_old_leaf+0xdf/0x3ce
    [<ffffffff86413a00>] ? ulist_add_merge+0x1b/0x127
    [<ffffffff86411688>] __resolve_indirect_refs+0x62a/0x667
    [<ffffffff863ef546>] ? btrfs_clear_lock_blocking_rw+0x78/0xbe
    [<ffffffff864122d3>] find_parent_nodes+0xaf3/0xfc6
    [<ffffffff86412838>] __btrfs_find_all_roots+0x92/0xf0
    [<ffffffff864128f2>] btrfs_find_all_roots+0x45/0x65
    [<ffffffff8639a75b>] ? btrfs_get_tree_mod_seq+0x2b/0x88
    [<ffffffff863e852e>] check_ref+0x64/0xc4
    [<ffffffff863e9e01>] btrfs_clone+0x66e/0xb5d
    [<ffffffff863ea77f>] btrfs_ioctl_clone+0x48f/0x5bb
    [<ffffffff86048a68>] ? native_sched_clock+0x28/0x77
    [<ffffffff863ed9b0>] btrfs_ioctl+0xabc/0x25cb
  (...)

The problem goes away by eleminating check_ref(), which no longer is
needed as its purpose was to get a value for the no_quota field of
a delayed reference (this patch removes the no_quota field as mentioned
earlier).

Reported-by: Stéphane Lesimple <stephane_btrfs@xxxxxxxxxxx>
Tested-by: Stéphane Lesimple <stephane_btrfs@xxxxxxxxxxx>
Reported-by: Elias Probst <mail@xxxxxxxxxxxxxx>
Reported-by: Peter Becker <floyd.net@xxxxxxxxx>
Reported-by: Malte Schröder <malte@xxxxxxxx>
Reported-by: Derek Dongray <derek@xxxxxxxxxxxxx>
Reported-by: Erkki Seppala <flux-btrfs@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx  # 4.2+
Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Reviewed-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
 fs/btrfs/ctree.h       |  4 ++--
 fs/btrfs/delayed-ref.c | 28 +++++++----------------
 fs/btrfs/delayed-ref.h |  7 ++----
 fs/btrfs/extent-tree.c | 45 +++++++++++++-----------------------
 fs/btrfs/file.c        | 10 ++++----
 fs/btrfs/inode.c       |  4 ++--
 fs/btrfs/ioctl.c       | 62 +-------------------------------------------------
 fs/btrfs/relocation.c  | 16 ++++++-------
 fs/btrfs/tree-log.c    |  2 +-
 9 files changed, 44 insertions(+), 134 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index aac314e..bb25b8d 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3404,7 +3404,7 @@ int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
 int btrfs_free_extent(struct btrfs_trans_handle *trans,
 		      struct btrfs_root *root,
 		      u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
-		      u64 owner, u64 offset, int no_quota);
+		      u64 owner, u64 offset);
 
 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len,
 			       int delalloc);
@@ -3417,7 +3417,7 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 			 struct btrfs_root *root,
 			 u64 bytenr, u64 num_bytes, u64 parent,
-			 u64 root_objectid, u64 owner, u64 offset, int no_quota);
+			 u64 root_objectid, u64 owner, u64 offset);
 
 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
 				   struct btrfs_root *root);
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 4832943..7832031 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -220,7 +220,7 @@ static bool merge_ref(struct btrfs_trans_handle *trans,
 		if (seq && next->seq >= seq)
 			goto next;
 
-		if (next->type != ref->type || next->no_quota != ref->no_quota)
+		if (next->type != ref->type)
 			goto next;
 
 		if ((ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
@@ -405,8 +405,7 @@ add_delayed_ref_tail_merge(struct btrfs_trans_handle *trans,
 	exist = list_entry(href->ref_list.prev, struct btrfs_delayed_ref_node,
 			   list);
 	/* No need to compare bytenr nor is_head */
-	if (exist->type != ref->type || exist->no_quota != ref->no_quota ||
-	    exist->seq != ref->seq)
+	if (exist->type != ref->type || exist->seq != ref->seq)
 		goto add_tail;
 
 	if ((exist->type == BTRFS_TREE_BLOCK_REF_KEY ||
@@ -637,7 +636,7 @@ add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 		     struct btrfs_delayed_ref_head *head_ref,
 		     struct btrfs_delayed_ref_node *ref, u64 bytenr,
 		     u64 num_bytes, u64 parent, u64 ref_root, int level,
-		     int action, int no_quota)
+		     int action)
 {
 	struct btrfs_delayed_tree_ref *full_ref;
 	struct btrfs_delayed_ref_root *delayed_refs;
@@ -659,7 +658,6 @@ add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 	ref->action = action;
 	ref->is_head = 0;
 	ref->in_tree = 1;
-	ref->no_quota = no_quota;
 	ref->seq = seq;
 
 	full_ref = btrfs_delayed_node_to_tree_ref(ref);
@@ -692,7 +690,7 @@ add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 		     struct btrfs_delayed_ref_head *head_ref,
 		     struct btrfs_delayed_ref_node *ref, u64 bytenr,
 		     u64 num_bytes, u64 parent, u64 ref_root, u64 owner,
-		     u64 offset, int action, int no_quota)
+		     u64 offset, int action)
 {
 	struct btrfs_delayed_data_ref *full_ref;
 	struct btrfs_delayed_ref_root *delayed_refs;
@@ -715,7 +713,6 @@ add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 	ref->action = action;
 	ref->is_head = 0;
 	ref->in_tree = 1;
-	ref->no_quota = no_quota;
 	ref->seq = seq;
 
 	full_ref = btrfs_delayed_node_to_data_ref(ref);
@@ -746,17 +743,13 @@ int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 			       struct btrfs_trans_handle *trans,
 			       u64 bytenr, u64 num_bytes, u64 parent,
 			       u64 ref_root,  int level, int action,
-			       struct btrfs_delayed_extent_op *extent_op,
-			       int no_quota)
+			       struct btrfs_delayed_extent_op *extent_op)
 {
 	struct btrfs_delayed_tree_ref *ref;
 	struct btrfs_delayed_ref_head *head_ref;
 	struct btrfs_delayed_ref_root *delayed_refs;
 	struct btrfs_qgroup_extent_record *record = NULL;
 
-	if (!is_fstree(ref_root) || !fs_info->quota_enabled)
-		no_quota = 0;
-
 	BUG_ON(extent_op && extent_op->is_data);
 	ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
 	if (!ref)
@@ -785,8 +778,7 @@ int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 					bytenr, num_bytes, action, 0);
 
 	add_delayed_tree_ref(fs_info, trans, head_ref, &ref->node, bytenr,
-				   num_bytes, parent, ref_root, level, action,
-				   no_quota);
+			     num_bytes, parent, ref_root, level, action);
 	spin_unlock(&delayed_refs->lock);
 
 	return 0;
@@ -807,17 +799,13 @@ int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 			       u64 bytenr, u64 num_bytes,
 			       u64 parent, u64 ref_root,
 			       u64 owner, u64 offset, int action,
-			       struct btrfs_delayed_extent_op *extent_op,
-			       int no_quota)
+			       struct btrfs_delayed_extent_op *extent_op)
 {
 	struct btrfs_delayed_data_ref *ref;
 	struct btrfs_delayed_ref_head *head_ref;
 	struct btrfs_delayed_ref_root *delayed_refs;
 	struct btrfs_qgroup_extent_record *record = NULL;
 
-	if (!is_fstree(ref_root) || !fs_info->quota_enabled)
-		no_quota = 0;
-
 	BUG_ON(extent_op && !extent_op->is_data);
 	ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
 	if (!ref)
@@ -853,7 +841,7 @@ int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 
 	add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 				   num_bytes, parent, ref_root, owner, offset,
-				   action, no_quota);
+				   action);
 	spin_unlock(&delayed_refs->lock);
 
 	return 0;
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index 13fb5e6..930887a 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -68,7 +68,6 @@ struct btrfs_delayed_ref_node {
 
 	unsigned int action:8;
 	unsigned int type:8;
-	unsigned int no_quota:1;
 	/* is this node still in the rbtree? */
 	unsigned int is_head:1;
 	unsigned int in_tree:1;
@@ -233,15 +232,13 @@ int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 			       struct btrfs_trans_handle *trans,
 			       u64 bytenr, u64 num_bytes, u64 parent,
 			       u64 ref_root, int level, int action,
-			       struct btrfs_delayed_extent_op *extent_op,
-			       int no_quota);
+			       struct btrfs_delayed_extent_op *extent_op);
 int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 			       struct btrfs_trans_handle *trans,
 			       u64 bytenr, u64 num_bytes,
 			       u64 parent, u64 ref_root,
 			       u64 owner, u64 offset, int action,
-			       struct btrfs_delayed_extent_op *extent_op,
-			       int no_quota);
+			       struct btrfs_delayed_extent_op *extent_op);
 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
 				struct btrfs_trans_handle *trans,
 				u64 bytenr, u64 num_bytes,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a66f59a..5d870c4 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -95,8 +95,7 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
 				     struct btrfs_root *root,
 				     u64 parent, u64 root_objectid,
 				     u64 flags, struct btrfs_disk_key *key,
-				     int level, struct btrfs_key *ins,
-				     int no_quota);
+				     int level, struct btrfs_key *ins);
 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *extent_root, u64 flags,
 			  int force);
@@ -1941,8 +1940,7 @@ int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 			 struct btrfs_root *root,
 			 u64 bytenr, u64 num_bytes, u64 parent,
-			 u64 root_objectid, u64 owner, u64 offset,
-			 int no_quota)
+			 u64 root_objectid, u64 owner, u64 offset)
 {
 	int ret;
 	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -1954,12 +1952,12 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 		ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
 					num_bytes,
 					parent, root_objectid, (int)owner,
-					BTRFS_ADD_DELAYED_REF, NULL, no_quota);
+					BTRFS_ADD_DELAYED_REF, NULL);
 	} else {
 		ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
 					num_bytes,
 					parent, root_objectid, owner, offset,
-					BTRFS_ADD_DELAYED_REF, NULL, no_quota);
+					BTRFS_ADD_DELAYED_REF, NULL);
 	}
 	return ret;
 }
@@ -1980,15 +1978,11 @@ static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 	u64 num_bytes = node->num_bytes;
 	u64 refs;
 	int ret;
-	int no_quota = node->no_quota;
 
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
 
-	if (!is_fstree(root_objectid) || !root->fs_info->quota_enabled)
-		no_quota = 1;
-
 	path->reada = 1;
 	path->leave_spinning = 1;
 	/* this will setup the path even if it fails to insert the back ref */
@@ -2223,8 +2217,7 @@ static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
 						parent, ref_root,
 						extent_op->flags_to_set,
 						&extent_op->key,
-						ref->level, &ins,
-						node->no_quota);
+						ref->level, &ins);
 	} else if (node->action == BTRFS_ADD_DELAYED_REF) {
 		ret = __btrfs_inc_extent_ref(trans, root, node,
 					     parent, ref_root,
@@ -3052,7 +3045,7 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
 	int level;
 	int ret = 0;
 	int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
-			    u64, u64, u64, u64, u64, u64, int);
+			    u64, u64, u64, u64, u64, u64);
 
 
 	if (btrfs_test_is_dummy_root(root))
@@ -3093,15 +3086,14 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
 			key.offset -= btrfs_file_extent_offset(buf, fi);
 			ret = process_func(trans, root, bytenr, num_bytes,
 					   parent, ref_root, key.objectid,
-					   key.offset, 1);
+					   key.offset);
 			if (ret)
 				goto fail;
 		} else {
 			bytenr = btrfs_node_blockptr(buf, i);
 			num_bytes = root->nodesize;
 			ret = process_func(trans, root, bytenr, num_bytes,
-					   parent, ref_root, level - 1, 0,
-					   1);
+					   parent, ref_root, level - 1, 0);
 			if (ret)
 				goto fail;
 		}
@@ -6151,7 +6143,6 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
 	int extent_slot = 0;
 	int found_extent = 0;
 	int num_to_del = 1;
-	int no_quota = node->no_quota;
 	u32 item_size;
 	u64 refs;
 	u64 bytenr = node->bytenr;
@@ -6160,9 +6151,6 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
 	bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
 						 SKINNY_METADATA);
 
-	if (!info->quota_enabled || !is_fstree(root_objectid))
-		no_quota = 1;
-
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
@@ -6488,7 +6476,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
 					buf->start, buf->len,
 					parent, root->root_key.objectid,
 					btrfs_header_level(buf),
-					BTRFS_DROP_DELAYED_REF, NULL, 0);
+					BTRFS_DROP_DELAYED_REF, NULL);
 		BUG_ON(ret); /* -ENOMEM */
 	}
 
@@ -6536,7 +6524,7 @@ out:
 /* Can return -ENOMEM */
 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 		      u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
-		      u64 owner, u64 offset, int no_quota)
+		      u64 owner, u64 offset)
 {
 	int ret;
 	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -6559,13 +6547,13 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 		ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
 					num_bytes,
 					parent, root_objectid, (int)owner,
-					BTRFS_DROP_DELAYED_REF, NULL, no_quota);
+					BTRFS_DROP_DELAYED_REF, NULL);
 	} else {
 		ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
 						num_bytes,
 						parent, root_objectid, owner,
 						offset, BTRFS_DROP_DELAYED_REF,
-						NULL, no_quota);
+						NULL);
 	}
 	return ret;
 }
@@ -7347,8 +7335,7 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
 				     struct btrfs_root *root,
 				     u64 parent, u64 root_objectid,
 				     u64 flags, struct btrfs_disk_key *key,
-				     int level, struct btrfs_key *ins,
-				     int no_quota)
+				     int level, struct btrfs_key *ins)
 {
 	int ret;
 	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -7438,7 +7425,7 @@ int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
 	ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
 					 ins->offset, 0,
 					 root_objectid, owner, offset,
-					 BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
+					 BTRFS_ADD_DELAYED_EXTENT, NULL);
 	return ret;
 }
 
@@ -7655,7 +7642,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
 						 ins.objectid, ins.offset,
 						 parent, root_objectid, level,
 						 BTRFS_ADD_DELAYED_EXTENT,
-						 extent_op, 0);
+						 extent_op);
 		if (ret)
 			goto out_free_delayed;
 	}
@@ -8203,7 +8190,7 @@ skip:
 			}
 		}
 		ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
-				root->root_key.objectid, level - 1, 0, 0);
+				root->root_key.objectid, level - 1, 0);
 		BUG_ON(ret); /* -ENOMEM */
 	}
 	btrfs_tree_unlock(next);
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index b823fac..7e55001 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -847,7 +847,7 @@ next_slot:
 						disk_bytenr, num_bytes, 0,
 						root->root_key.objectid,
 						new_key.objectid,
-						start - extent_offset, 1);
+						start - extent_offset);
 				BUG_ON(ret); /* -ENOMEM */
 			}
 			key.offset = start;
@@ -925,7 +925,7 @@ delete_extent_item:
 						disk_bytenr, num_bytes, 0,
 						root->root_key.objectid,
 						key.objectid, key.offset -
-						extent_offset, 0);
+						extent_offset);
 				BUG_ON(ret); /* -ENOMEM */
 				inode_sub_bytes(inode,
 						extent_end - key.offset);
@@ -1204,7 +1204,7 @@ again:
 
 		ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
 					   root->root_key.objectid,
-					   ino, orig_offset, 1);
+					   ino, orig_offset);
 		BUG_ON(ret); /* -ENOMEM */
 
 		if (split == start) {
@@ -1231,7 +1231,7 @@ again:
 		del_nr++;
 		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 					0, root->root_key.objectid,
-					ino, orig_offset, 0);
+					ino, orig_offset);
 		BUG_ON(ret); /* -ENOMEM */
 	}
 	other_start = 0;
@@ -1248,7 +1248,7 @@ again:
 		del_nr++;
 		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 					0, root->root_key.objectid,
-					ino, orig_offset, 0);
+					ino, orig_offset);
 		BUG_ON(ret); /* -ENOMEM */
 	}
 	if (del_nr == 0) {
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index b54e630..2a6e24a 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2569,7 +2569,7 @@ again:
 	ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
 			new->disk_len, 0,
 			backref->root_id, backref->inum,
-			new->file_pos, 0);	/* start - extent_offset */
+			new->file_pos);	/* start - extent_offset */
 	if (ret) {
 		btrfs_abort_transaction(trans, root, ret);
 		goto out_free_path;
@@ -4428,7 +4428,7 @@ delete:
 			ret = btrfs_free_extent(trans, root, extent_start,
 						extent_num_bytes, 0,
 						btrfs_header_owner(leaf),
-						ino, extent_offset, 0);
+						ino, extent_offset);
 			BUG_ON(ret);
 			if (btrfs_should_throttle_delayed_refs(trans, root))
 				btrfs_async_run_delayed_refs(root,
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 641d3dc..abf3e9b 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3195,41 +3195,6 @@ out:
 	return ret;
 }
 
-/* Helper to check and see if this root currently has a ref on the given disk
- * bytenr.  If it does then we need to update the quota for this root.  This
- * doesn't do anything if quotas aren't enabled.
- */
-static int check_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
-		     u64 disko)
-{
-	struct seq_list tree_mod_seq_elem = SEQ_LIST_INIT(tree_mod_seq_elem);
-	struct ulist *roots;
-	struct ulist_iterator uiter;
-	struct ulist_node *root_node = NULL;
-	int ret;
-
-	if (!root->fs_info->quota_enabled)
-		return 1;
-
-	btrfs_get_tree_mod_seq(root->fs_info, &tree_mod_seq_elem);
-	ret = btrfs_find_all_roots(trans, root->fs_info, disko,
-				   tree_mod_seq_elem.seq, &roots);
-	if (ret < 0)
-		goto out;
-	ret = 0;
-	ULIST_ITER_INIT(&uiter);
-	while ((root_node = ulist_next(roots, &uiter))) {
-		if (root_node->val == root->objectid) {
-			ret = 1;
-			break;
-		}
-	}
-	ulist_free(roots);
-out:
-	btrfs_put_tree_mod_seq(root->fs_info, &tree_mod_seq_elem);
-	return ret;
-}
-
 static int clone_finish_inode_update(struct btrfs_trans_handle *trans,
 				     struct inode *inode,
 				     u64 endoff,
@@ -3344,9 +3309,7 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
 	u32 nritems;
 	int slot;
 	int ret;
-	int no_quota;
 	const u64 len = olen_aligned;
-	u64 last_disko = 0;
 	u64 last_dest_end = destoff;
 
 	ret = -ENOMEM;
@@ -3392,7 +3355,6 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
 
 		nritems = btrfs_header_nritems(path->nodes[0]);
 process_slot:
-		no_quota = 1;
 		if (path->slots[0] >= nritems) {
 			ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
 			if (ret < 0)
@@ -3544,35 +3506,13 @@ process_slot:
 				btrfs_set_file_extent_num_bytes(leaf, extent,
 								datal);
 
-				/*
-				 * We need to look up the roots that point at
-				 * this bytenr and see if the new root does.  If
-				 * it does not we need to make sure we update
-				 * quotas appropriately.
-				 */
-				if (disko && root != BTRFS_I(src)->root &&
-				    disko != last_disko) {
-					no_quota = check_ref(trans, root,
-							     disko);
-					if (no_quota < 0) {
-						btrfs_abort_transaction(trans,
-									root,
-									ret);
-						btrfs_end_transaction(trans,
-								      root);
-						ret = no_quota;
-						goto out;
-					}
-				}
-
 				if (disko) {
 					inode_add_bytes(inode, datal);
 					ret = btrfs_inc_extent_ref(trans, root,
 							disko, diskl, 0,
 							root->root_key.objectid,
 							btrfs_ino(inode),
-							new_key.offset - datao,
-							no_quota);
+							new_key.offset - datao);
 					if (ret) {
 						btrfs_abort_transaction(trans,
 									root,
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 88cbb59..3a828a3 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1716,7 +1716,7 @@ int replace_file_extents(struct btrfs_trans_handle *trans,
 		ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
 					   num_bytes, parent,
 					   btrfs_header_owner(leaf),
-					   key.objectid, key.offset, 1);
+					   key.objectid, key.offset);
 		if (ret) {
 			btrfs_abort_transaction(trans, root, ret);
 			break;
@@ -1724,7 +1724,7 @@ int replace_file_extents(struct btrfs_trans_handle *trans,
 
 		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 					parent, btrfs_header_owner(leaf),
-					key.objectid, key.offset, 1);
+					key.objectid, key.offset);
 		if (ret) {
 			btrfs_abort_transaction(trans, root, ret);
 			break;
@@ -1900,23 +1900,21 @@ again:
 
 		ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
 					path->nodes[level]->start,
-					src->root_key.objectid, level - 1, 0,
-					1);
+					src->root_key.objectid, level - 1, 0);
 		BUG_ON(ret);
 		ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
 					0, dest->root_key.objectid, level - 1,
-					0, 1);
+					0);
 		BUG_ON(ret);
 
 		ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
 					path->nodes[level]->start,
-					src->root_key.objectid, level - 1, 0,
-					1);
+					src->root_key.objectid, level - 1, 0);
 		BUG_ON(ret);
 
 		ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
 					0, dest->root_key.objectid, level - 1,
-					0, 1);
+					0);
 		BUG_ON(ret);
 
 		btrfs_unlock_up_safe(path, 0);
@@ -2746,7 +2744,7 @@ static int do_relocation(struct btrfs_trans_handle *trans,
 						node->eb->start, blocksize,
 						upper->eb->start,
 						btrfs_header_owner(upper->eb),
-						node->level, 0, 1);
+						node->level, 0);
 			BUG_ON(ret);
 
 			ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 9c45431..7639695 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -700,7 +700,7 @@ static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
 				ret = btrfs_inc_extent_ref(trans, root,
 						ins.objectid, ins.offset,
 						0, root->root_key.objectid,
-						key->objectid, offset, 0);
+						key->objectid, offset);
 				if (ret)
 					goto out;
 			} else {
-- 
2.1.3

>From 276b67714b35e9f6ce23c4bc0c750ad007e5a52c Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana@xxxxxxxx>
Date: Fri, 23 Oct 2015 07:52:54 +0100
Subject: [PATCH 2/2] Btrfs: fix regression running delayed references when
 using qgroups
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit b06c4bf5c874a57254b197f53ddf588e7a24a2bf upstream.

In the kernel 4.2 merge window we had a big changes to the implementation
of delayed references and qgroups which made the no_quota field of delayed
references not used anymore. More specifically the no_quota field is not
used anymore as of:

  commit 0ed4792af0e8 ("btrfs: qgroup: Switch to new extent-oriented qgroup mechanism.")

Leaving the no_quota field actually prevents delayed references from
getting merged, which in turn cause the following BUG_ON(), at
fs/btrfs/extent-tree.c, to be hit when qgroups are enabled:

  static int run_delayed_tree_ref(...)
  {
     (...)
     BUG_ON(node->ref_mod != 1);
     (...)
  }

This happens on a scenario like the following:

  1) Ref1 bytenr X, action = BTRFS_ADD_DELAYED_REF, no_quota = 1, added.

  2) Ref2 bytenr X, action = BTRFS_DROP_DELAYED_REF, no_quota = 0, added.
     It's not merged with Ref1 because Ref1->no_quota != Ref2->no_quota.

  3) Ref3 bytenr X, action = BTRFS_ADD_DELAYED_REF, no_quota = 1, added.
     It's not merged with the reference at the tail of the list of refs
     for bytenr X because the reference at the tail, Ref2 is incompatible
     due to Ref2->no_quota != Ref3->no_quota.

  4) Ref4 bytenr X, action = BTRFS_DROP_DELAYED_REF, no_quota = 0, added.
     It's not merged with the reference at the tail of the list of refs
     for bytenr X because the reference at the tail, Ref3 is incompatible
     due to Ref3->no_quota != Ref4->no_quota.

  5) We run delayed references, trigger merging of delayed references,
     through __btrfs_run_delayed_refs() -> btrfs_merge_delayed_refs().

  6) Ref1 and Ref3 are merged as Ref1->no_quota = Ref3->no_quota and
     all other conditions are satisfied too. So Ref1 gets a ref_mod
     value of 2.

  7) Ref2 and Ref4 are merged as Ref2->no_quota = Ref4->no_quota and
     all other conditions are satisfied too. So Ref2 gets a ref_mod
     value of 2.

  8) Ref1 and Ref2 aren't merged, because they have different values
     for their no_quota field.

  9) Delayed reference Ref1 is picked for running (select_delayed_ref()
     always prefers references with an action == BTRFS_ADD_DELAYED_REF).
     So run_delayed_tree_ref() is called for Ref1 which triggers the
     BUG_ON because Ref1->red_mod != 1 (equals 2).

So fix this by removing the no_quota field, as it's not used anymore as
of commit 0ed4792af0e8 ("btrfs: qgroup: Switch to new extent-oriented
qgroup mechanism.").

The use of no_quota was also buggy in at least two places:

1) At delayed-refs.c:btrfs_add_delayed_tree_ref() - we were setting
   no_quota to 0 instead of 1 when the following condition was true:
   is_fstree(ref_root) || !fs_info->quota_enabled

2) At extent-tree.c:__btrfs_inc_extent_ref() - we were attempting to
   reset a node's no_quota when the condition "!is_fstree(root_objectid)
   || !root->fs_info->quota_enabled" was true but we did it only in
   an unused local stack variable, that is, we never reset the no_quota
   value in the node itself.

This fixes the remainder of problems several people have been having when
running delayed references, mostly while a balance is running in parallel,
on a 4.2+ kernel.

Very special thanks to Stéphane Lesimple for helping debugging this issue
and testing this fix on his multi terabyte filesystem (which took more
than one day to balance alone, plus fsck, etc).

Also, this fixes deadlock issue when using the clone ioctl with qgroups
enabled, as reported by Elias Probst in the mailing list. The deadlock
happens because after calling btrfs_insert_empty_item we have our path
holding a write lock on a leaf of the fs/subvol tree and then before
releasing the path we called check_ref() which did backref walking, when
qgroups are enabled, and tried to read lock the same leaf. The trace for
this case is the following:

  INFO: task systemd-nspawn:6095 blocked for more than 120 seconds.
  (...)
  Call Trace:
    [<ffffffff86999201>] schedule+0x74/0x83
    [<ffffffff863ef64c>] btrfs_tree_read_lock+0xc0/0xea
    [<ffffffff86137ed7>] ? wait_woken+0x74/0x74
    [<ffffffff8639f0a7>] btrfs_search_old_slot+0x51a/0x810
    [<ffffffff863a129b>] btrfs_next_old_leaf+0xdf/0x3ce
    [<ffffffff86413a00>] ? ulist_add_merge+0x1b/0x127
    [<ffffffff86411688>] __resolve_indirect_refs+0x62a/0x667
    [<ffffffff863ef546>] ? btrfs_clear_lock_blocking_rw+0x78/0xbe
    [<ffffffff864122d3>] find_parent_nodes+0xaf3/0xfc6
    [<ffffffff86412838>] __btrfs_find_all_roots+0x92/0xf0
    [<ffffffff864128f2>] btrfs_find_all_roots+0x45/0x65
    [<ffffffff8639a75b>] ? btrfs_get_tree_mod_seq+0x2b/0x88
    [<ffffffff863e852e>] check_ref+0x64/0xc4
    [<ffffffff863e9e01>] btrfs_clone+0x66e/0xb5d
    [<ffffffff863ea77f>] btrfs_ioctl_clone+0x48f/0x5bb
    [<ffffffff86048a68>] ? native_sched_clock+0x28/0x77
    [<ffffffff863ed9b0>] btrfs_ioctl+0xabc/0x25cb
  (...)

The problem goes away by eleminating check_ref(), which no longer is
needed as its purpose was to get a value for the no_quota field of
a delayed reference (this patch removes the no_quota field as mentioned
earlier).

Reported-by: Stéphane Lesimple <stephane_btrfs@xxxxxxxxxxx>
Tested-by: Stéphane Lesimple <stephane_btrfs@xxxxxxxxxxx>
Reported-by: Elias Probst <mail@xxxxxxxxxxxxxx>
Reported-by: Peter Becker <floyd.net@xxxxxxxxx>
Reported-by: Malte Schröder <malte@xxxxxxxx>
Reported-by: Derek Dongray <derek@xxxxxxxxxxxxx>
Reported-by: Erkki Seppala <flux-btrfs@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx  # 4.2+
Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Reviewed-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
 fs/btrfs/ctree.h       |  4 ++--
 fs/btrfs/delayed-ref.c | 28 +++++++----------------
 fs/btrfs/delayed-ref.h |  7 ++----
 fs/btrfs/extent-tree.c | 45 +++++++++++++-----------------------
 fs/btrfs/file.c        | 10 ++++----
 fs/btrfs/inode.c       |  4 ++--
 fs/btrfs/ioctl.c       | 62 +-------------------------------------------------
 fs/btrfs/relocation.c  | 16 ++++++-------
 fs/btrfs/tree-log.c    |  2 +-
 9 files changed, 44 insertions(+), 134 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 938efe3..94eea1f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3398,7 +3398,7 @@ int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
 int btrfs_free_extent(struct btrfs_trans_handle *trans,
 		      struct btrfs_root *root,
 		      u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
-		      u64 owner, u64 offset, int no_quota);
+		      u64 owner, u64 offset);
 
 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len,
 			       int delalloc);
@@ -3411,7 +3411,7 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 			 struct btrfs_root *root,
 			 u64 bytenr, u64 num_bytes, u64 parent,
-			 u64 root_objectid, u64 owner, u64 offset, int no_quota);
+			 u64 root_objectid, u64 owner, u64 offset);
 
 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
 				   struct btrfs_root *root);
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 4832943..7832031 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -220,7 +220,7 @@ static bool merge_ref(struct btrfs_trans_handle *trans,
 		if (seq && next->seq >= seq)
 			goto next;
 
-		if (next->type != ref->type || next->no_quota != ref->no_quota)
+		if (next->type != ref->type)
 			goto next;
 
 		if ((ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
@@ -405,8 +405,7 @@ add_delayed_ref_tail_merge(struct btrfs_trans_handle *trans,
 	exist = list_entry(href->ref_list.prev, struct btrfs_delayed_ref_node,
 			   list);
 	/* No need to compare bytenr nor is_head */
-	if (exist->type != ref->type || exist->no_quota != ref->no_quota ||
-	    exist->seq != ref->seq)
+	if (exist->type != ref->type || exist->seq != ref->seq)
 		goto add_tail;
 
 	if ((exist->type == BTRFS_TREE_BLOCK_REF_KEY ||
@@ -637,7 +636,7 @@ add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 		     struct btrfs_delayed_ref_head *head_ref,
 		     struct btrfs_delayed_ref_node *ref, u64 bytenr,
 		     u64 num_bytes, u64 parent, u64 ref_root, int level,
-		     int action, int no_quota)
+		     int action)
 {
 	struct btrfs_delayed_tree_ref *full_ref;
 	struct btrfs_delayed_ref_root *delayed_refs;
@@ -659,7 +658,6 @@ add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 	ref->action = action;
 	ref->is_head = 0;
 	ref->in_tree = 1;
-	ref->no_quota = no_quota;
 	ref->seq = seq;
 
 	full_ref = btrfs_delayed_node_to_tree_ref(ref);
@@ -692,7 +690,7 @@ add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 		     struct btrfs_delayed_ref_head *head_ref,
 		     struct btrfs_delayed_ref_node *ref, u64 bytenr,
 		     u64 num_bytes, u64 parent, u64 ref_root, u64 owner,
-		     u64 offset, int action, int no_quota)
+		     u64 offset, int action)
 {
 	struct btrfs_delayed_data_ref *full_ref;
 	struct btrfs_delayed_ref_root *delayed_refs;
@@ -715,7 +713,6 @@ add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 	ref->action = action;
 	ref->is_head = 0;
 	ref->in_tree = 1;
-	ref->no_quota = no_quota;
 	ref->seq = seq;
 
 	full_ref = btrfs_delayed_node_to_data_ref(ref);
@@ -746,17 +743,13 @@ int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 			       struct btrfs_trans_handle *trans,
 			       u64 bytenr, u64 num_bytes, u64 parent,
 			       u64 ref_root,  int level, int action,
-			       struct btrfs_delayed_extent_op *extent_op,
-			       int no_quota)
+			       struct btrfs_delayed_extent_op *extent_op)
 {
 	struct btrfs_delayed_tree_ref *ref;
 	struct btrfs_delayed_ref_head *head_ref;
 	struct btrfs_delayed_ref_root *delayed_refs;
 	struct btrfs_qgroup_extent_record *record = NULL;
 
-	if (!is_fstree(ref_root) || !fs_info->quota_enabled)
-		no_quota = 0;
-
 	BUG_ON(extent_op && extent_op->is_data);
 	ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
 	if (!ref)
@@ -785,8 +778,7 @@ int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 					bytenr, num_bytes, action, 0);
 
 	add_delayed_tree_ref(fs_info, trans, head_ref, &ref->node, bytenr,
-				   num_bytes, parent, ref_root, level, action,
-				   no_quota);
+			     num_bytes, parent, ref_root, level, action);
 	spin_unlock(&delayed_refs->lock);
 
 	return 0;
@@ -807,17 +799,13 @@ int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 			       u64 bytenr, u64 num_bytes,
 			       u64 parent, u64 ref_root,
 			       u64 owner, u64 offset, int action,
-			       struct btrfs_delayed_extent_op *extent_op,
-			       int no_quota)
+			       struct btrfs_delayed_extent_op *extent_op)
 {
 	struct btrfs_delayed_data_ref *ref;
 	struct btrfs_delayed_ref_head *head_ref;
 	struct btrfs_delayed_ref_root *delayed_refs;
 	struct btrfs_qgroup_extent_record *record = NULL;
 
-	if (!is_fstree(ref_root) || !fs_info->quota_enabled)
-		no_quota = 0;
-
 	BUG_ON(extent_op && !extent_op->is_data);
 	ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
 	if (!ref)
@@ -853,7 +841,7 @@ int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 
 	add_delayed_data_ref(fs_info, trans, head_ref, &ref->node, bytenr,
 				   num_bytes, parent, ref_root, owner, offset,
-				   action, no_quota);
+				   action);
 	spin_unlock(&delayed_refs->lock);
 
 	return 0;
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index 13fb5e6..930887a 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -68,7 +68,6 @@ struct btrfs_delayed_ref_node {
 
 	unsigned int action:8;
 	unsigned int type:8;
-	unsigned int no_quota:1;
 	/* is this node still in the rbtree? */
 	unsigned int is_head:1;
 	unsigned int in_tree:1;
@@ -233,15 +232,13 @@ int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
 			       struct btrfs_trans_handle *trans,
 			       u64 bytenr, u64 num_bytes, u64 parent,
 			       u64 ref_root, int level, int action,
-			       struct btrfs_delayed_extent_op *extent_op,
-			       int no_quota);
+			       struct btrfs_delayed_extent_op *extent_op);
 int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
 			       struct btrfs_trans_handle *trans,
 			       u64 bytenr, u64 num_bytes,
 			       u64 parent, u64 ref_root,
 			       u64 owner, u64 offset, int action,
-			       struct btrfs_delayed_extent_op *extent_op,
-			       int no_quota);
+			       struct btrfs_delayed_extent_op *extent_op);
 int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
 				struct btrfs_trans_handle *trans,
 				u64 bytenr, u64 num_bytes,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 00158bf..cadacf6 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -95,8 +95,7 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
 				     struct btrfs_root *root,
 				     u64 parent, u64 root_objectid,
 				     u64 flags, struct btrfs_disk_key *key,
-				     int level, struct btrfs_key *ins,
-				     int no_quota);
+				     int level, struct btrfs_key *ins);
 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 			  struct btrfs_root *extent_root, u64 flags,
 			  int force);
@@ -2009,8 +2008,7 @@ int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 			 struct btrfs_root *root,
 			 u64 bytenr, u64 num_bytes, u64 parent,
-			 u64 root_objectid, u64 owner, u64 offset,
-			 int no_quota)
+			 u64 root_objectid, u64 owner, u64 offset)
 {
 	int ret;
 	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -2022,12 +2020,12 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 		ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
 					num_bytes,
 					parent, root_objectid, (int)owner,
-					BTRFS_ADD_DELAYED_REF, NULL, no_quota);
+					BTRFS_ADD_DELAYED_REF, NULL);
 	} else {
 		ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
 					num_bytes,
 					parent, root_objectid, owner, offset,
-					BTRFS_ADD_DELAYED_REF, NULL, no_quota);
+					BTRFS_ADD_DELAYED_REF, NULL);
 	}
 	return ret;
 }
@@ -2048,15 +2046,11 @@ static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
 	u64 num_bytes = node->num_bytes;
 	u64 refs;
 	int ret;
-	int no_quota = node->no_quota;
 
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
 
-	if (!is_fstree(root_objectid) || !root->fs_info->quota_enabled)
-		no_quota = 1;
-
 	path->reada = 1;
 	path->leave_spinning = 1;
 	/* this will setup the path even if it fails to insert the back ref */
@@ -2291,8 +2285,7 @@ static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
 						parent, ref_root,
 						extent_op->flags_to_set,
 						&extent_op->key,
-						ref->level, &ins,
-						node->no_quota);
+						ref->level, &ins);
 	} else if (node->action == BTRFS_ADD_DELAYED_REF) {
 		ret = __btrfs_inc_extent_ref(trans, root, node,
 					     parent, ref_root,
@@ -3123,7 +3116,7 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
 	int level;
 	int ret = 0;
 	int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
-			    u64, u64, u64, u64, u64, u64, int);
+			    u64, u64, u64, u64, u64, u64);
 
 
 	if (btrfs_test_is_dummy_root(root))
@@ -3164,15 +3157,14 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
 			key.offset -= btrfs_file_extent_offset(buf, fi);
 			ret = process_func(trans, root, bytenr, num_bytes,
 					   parent, ref_root, key.objectid,
-					   key.offset, 1);
+					   key.offset);
 			if (ret)
 				goto fail;
 		} else {
 			bytenr = btrfs_node_blockptr(buf, i);
 			num_bytes = root->nodesize;
 			ret = process_func(trans, root, bytenr, num_bytes,
-					   parent, ref_root, level - 1, 0,
-					   1);
+					   parent, ref_root, level - 1, 0);
 			if (ret)
 				goto fail;
 		}
@@ -6247,7 +6239,6 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
 	int extent_slot = 0;
 	int found_extent = 0;
 	int num_to_del = 1;
-	int no_quota = node->no_quota;
 	u32 item_size;
 	u64 refs;
 	u64 bytenr = node->bytenr;
@@ -6256,9 +6247,6 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
 	bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
 						 SKINNY_METADATA);
 
-	if (!info->quota_enabled || !is_fstree(root_objectid))
-		no_quota = 1;
-
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;
@@ -6584,7 +6572,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
 					buf->start, buf->len,
 					parent, root->root_key.objectid,
 					btrfs_header_level(buf),
-					BTRFS_DROP_DELAYED_REF, NULL, 0);
+					BTRFS_DROP_DELAYED_REF, NULL);
 		BUG_ON(ret); /* -ENOMEM */
 	}
 
@@ -6632,7 +6620,7 @@ out:
 /* Can return -ENOMEM */
 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 		      u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
-		      u64 owner, u64 offset, int no_quota)
+		      u64 owner, u64 offset)
 {
 	int ret;
 	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -6655,13 +6643,13 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 		ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
 					num_bytes,
 					parent, root_objectid, (int)owner,
-					BTRFS_DROP_DELAYED_REF, NULL, no_quota);
+					BTRFS_DROP_DELAYED_REF, NULL);
 	} else {
 		ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
 						num_bytes,
 						parent, root_objectid, owner,
 						offset, BTRFS_DROP_DELAYED_REF,
-						NULL, no_quota);
+						NULL);
 	}
 	return ret;
 }
@@ -7443,8 +7431,7 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
 				     struct btrfs_root *root,
 				     u64 parent, u64 root_objectid,
 				     u64 flags, struct btrfs_disk_key *key,
-				     int level, struct btrfs_key *ins,
-				     int no_quota)
+				     int level, struct btrfs_key *ins)
 {
 	int ret;
 	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -7534,7 +7521,7 @@ int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
 	ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
 					 ins->offset, 0,
 					 root_objectid, owner, offset,
-					 BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
+					 BTRFS_ADD_DELAYED_EXTENT, NULL);
 	return ret;
 }
 
@@ -7748,7 +7735,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
 						 ins.objectid, ins.offset,
 						 parent, root_objectid, level,
 						 BTRFS_ADD_DELAYED_EXTENT,
-						 extent_op, 0);
+						 extent_op);
 		if (ret)
 			goto out_free_delayed;
 	}
@@ -8296,7 +8283,7 @@ skip:
 			}
 		}
 		ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
-				root->root_key.objectid, level - 1, 0, 0);
+				root->root_key.objectid, level - 1, 0);
 		BUG_ON(ret); /* -ENOMEM */
 	}
 	btrfs_tree_unlock(next);
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 8c6f247..e05cd9a 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -847,7 +847,7 @@ next_slot:
 						disk_bytenr, num_bytes, 0,
 						root->root_key.objectid,
 						new_key.objectid,
-						start - extent_offset, 1);
+						start - extent_offset);
 				BUG_ON(ret); /* -ENOMEM */
 			}
 			key.offset = start;
@@ -925,7 +925,7 @@ delete_extent_item:
 						disk_bytenr, num_bytes, 0,
 						root->root_key.objectid,
 						key.objectid, key.offset -
-						extent_offset, 0);
+						extent_offset);
 				BUG_ON(ret); /* -ENOMEM */
 				inode_sub_bytes(inode,
 						extent_end - key.offset);
@@ -1204,7 +1204,7 @@ again:
 
 		ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
 					   root->root_key.objectid,
-					   ino, orig_offset, 1);
+					   ino, orig_offset);
 		BUG_ON(ret); /* -ENOMEM */
 
 		if (split == start) {
@@ -1231,7 +1231,7 @@ again:
 		del_nr++;
 		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 					0, root->root_key.objectid,
-					ino, orig_offset, 0);
+					ino, orig_offset);
 		BUG_ON(ret); /* -ENOMEM */
 	}
 	other_start = 0;
@@ -1248,7 +1248,7 @@ again:
 		del_nr++;
 		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 					0, root->root_key.objectid,
-					ino, orig_offset, 0);
+					ino, orig_offset);
 		BUG_ON(ret); /* -ENOMEM */
 	}
 	if (del_nr == 0) {
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 611b66d..226c4bb 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2573,7 +2573,7 @@ again:
 	ret = btrfs_inc_extent_ref(trans, root, new->bytenr,
 			new->disk_len, 0,
 			backref->root_id, backref->inum,
-			new->file_pos, 0);	/* start - extent_offset */
+			new->file_pos);	/* start - extent_offset */
 	if (ret) {
 		btrfs_abort_transaction(trans, root, ret);
 		goto out_free_path;
@@ -4461,7 +4461,7 @@ delete:
 			ret = btrfs_free_extent(trans, root, extent_start,
 						extent_num_bytes, 0,
 						btrfs_header_owner(leaf),
-						ino, extent_offset, 0);
+						ino, extent_offset);
 			BUG_ON(ret);
 			if (btrfs_should_throttle_delayed_refs(trans, root))
 				btrfs_async_run_delayed_refs(root,
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 8d20f3b..9f96436 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3203,41 +3203,6 @@ out:
 	return ret;
 }
 
-/* Helper to check and see if this root currently has a ref on the given disk
- * bytenr.  If it does then we need to update the quota for this root.  This
- * doesn't do anything if quotas aren't enabled.
- */
-static int check_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
-		     u64 disko)
-{
-	struct seq_list tree_mod_seq_elem = SEQ_LIST_INIT(tree_mod_seq_elem);
-	struct ulist *roots;
-	struct ulist_iterator uiter;
-	struct ulist_node *root_node = NULL;
-	int ret;
-
-	if (!root->fs_info->quota_enabled)
-		return 1;
-
-	btrfs_get_tree_mod_seq(root->fs_info, &tree_mod_seq_elem);
-	ret = btrfs_find_all_roots(trans, root->fs_info, disko,
-				   tree_mod_seq_elem.seq, &roots);
-	if (ret < 0)
-		goto out;
-	ret = 0;
-	ULIST_ITER_INIT(&uiter);
-	while ((root_node = ulist_next(roots, &uiter))) {
-		if (root_node->val == root->objectid) {
-			ret = 1;
-			break;
-		}
-	}
-	ulist_free(roots);
-out:
-	btrfs_put_tree_mod_seq(root->fs_info, &tree_mod_seq_elem);
-	return ret;
-}
-
 static int clone_finish_inode_update(struct btrfs_trans_handle *trans,
 				     struct inode *inode,
 				     u64 endoff,
@@ -3352,9 +3317,7 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
 	u32 nritems;
 	int slot;
 	int ret;
-	int no_quota;
 	const u64 len = olen_aligned;
-	u64 last_disko = 0;
 	u64 last_dest_end = destoff;
 
 	ret = -ENOMEM;
@@ -3400,7 +3363,6 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
 
 		nritems = btrfs_header_nritems(path->nodes[0]);
 process_slot:
-		no_quota = 1;
 		if (path->slots[0] >= nritems) {
 			ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
 			if (ret < 0)
@@ -3552,35 +3514,13 @@ process_slot:
 				btrfs_set_file_extent_num_bytes(leaf, extent,
 								datal);
 
-				/*
-				 * We need to look up the roots that point at
-				 * this bytenr and see if the new root does.  If
-				 * it does not we need to make sure we update
-				 * quotas appropriately.
-				 */
-				if (disko && root != BTRFS_I(src)->root &&
-				    disko != last_disko) {
-					no_quota = check_ref(trans, root,
-							     disko);
-					if (no_quota < 0) {
-						btrfs_abort_transaction(trans,
-									root,
-									ret);
-						btrfs_end_transaction(trans,
-								      root);
-						ret = no_quota;
-						goto out;
-					}
-				}
-
 				if (disko) {
 					inode_add_bytes(inode, datal);
 					ret = btrfs_inc_extent_ref(trans, root,
 							disko, diskl, 0,
 							root->root_key.objectid,
 							btrfs_ino(inode),
-							new_key.offset - datao,
-							no_quota);
+							new_key.offset - datao);
 					if (ret) {
 						btrfs_abort_transaction(trans,
 									root,
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 303babe..ab507e3 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1716,7 +1716,7 @@ int replace_file_extents(struct btrfs_trans_handle *trans,
 		ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
 					   num_bytes, parent,
 					   btrfs_header_owner(leaf),
-					   key.objectid, key.offset, 1);
+					   key.objectid, key.offset);
 		if (ret) {
 			btrfs_abort_transaction(trans, root, ret);
 			break;
@@ -1724,7 +1724,7 @@ int replace_file_extents(struct btrfs_trans_handle *trans,
 
 		ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
 					parent, btrfs_header_owner(leaf),
-					key.objectid, key.offset, 1);
+					key.objectid, key.offset);
 		if (ret) {
 			btrfs_abort_transaction(trans, root, ret);
 			break;
@@ -1900,23 +1900,21 @@ again:
 
 		ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
 					path->nodes[level]->start,
-					src->root_key.objectid, level - 1, 0,
-					1);
+					src->root_key.objectid, level - 1, 0);
 		BUG_ON(ret);
 		ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
 					0, dest->root_key.objectid, level - 1,
-					0, 1);
+					0);
 		BUG_ON(ret);
 
 		ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
 					path->nodes[level]->start,
-					src->root_key.objectid, level - 1, 0,
-					1);
+					src->root_key.objectid, level - 1, 0);
 		BUG_ON(ret);
 
 		ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
 					0, dest->root_key.objectid, level - 1,
-					0, 1);
+					0);
 		BUG_ON(ret);
 
 		btrfs_unlock_up_safe(path, 0);
@@ -2745,7 +2743,7 @@ static int do_relocation(struct btrfs_trans_handle *trans,
 						node->eb->start, blocksize,
 						upper->eb->start,
 						btrfs_header_owner(upper->eb),
-						node->level, 0, 1);
+						node->level, 0);
 			BUG_ON(ret);
 
 			ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 1bbaace..6f8af2d 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -691,7 +691,7 @@ static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
 				ret = btrfs_inc_extent_ref(trans, root,
 						ins.objectid, ins.offset,
 						0, root->root_key.objectid,
-						key->objectid, offset, 0);
+						key->objectid, offset);
 				if (ret)
 					goto out;
 			} else {
-- 
2.1.3


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