From 14ae4ec1ee1466b701e0518f9acbb0bbd8ab0684 Mon Sep 17 00:00:00 2001
From: Qu Wenruo <wqu@suse.com>
Date: Fri, 10 May 2019 12:45:05 +0800
Git-commit: 14ae4ec1ee1466b701e0518f9acbb0bbd8ab0684
Patch-mainline: v5.2-rc2
References: bsc#1063638 bsc#1128052 bsc#1108838
Subject: [PATCH] btrfs: extent-tree: Fix a bug that btrfs is unable to add
 pinned bytes

Commit ddf30cf03fb5 ("btrfs: extent-tree: Use btrfs_ref to refactor
add_pinned_bytes()") refactored add_pinned_bytes(), but during that
refactor, there are two callers which add the pinned bytes instead
of subtracting.

That refactor misses those two caller, causing incorrect pinned bytes
calculation and resulting unexpected ENOSPC error.

Fix it by adding a new parameter @sign to restore the original behavior.

Reported-by: kernel test robot <rong.a.chen@intel.com>
Fixes: ddf30cf03fb5 ("btrfs: extent-tree: Use btrfs_ref to refactor add_pinned_bytes()")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/extent-tree.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -768,12 +768,14 @@ static struct btrfs_space_info *__find_s
 }
 
 static void add_pinned_bytes(struct btrfs_fs_info *fs_info,
-			     struct btrfs_ref *ref)
+			     struct btrfs_ref *ref, int sign)
 {
 	struct btrfs_space_info *space_info;
-	s64 num_bytes = -ref->len;
+	s64 num_bytes;
 	u64 flags;
 
+	ASSERT(sign == 1 || sign == -1);
+	num_bytes = sign * ref->len;
 	if (ref->type == BTRFS_REF_METADATA) {
 		if (ref->tree_ref.root == BTRFS_CHUNK_TREE_OBJECTID)
 			flags = BTRFS_BLOCK_GROUP_SYSTEM;
@@ -2129,7 +2131,7 @@ int btrfs_inc_extent_ref(struct btrfs_tr
 						 &old_ref_mod, &new_ref_mod);
 
 	if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0)
-		add_pinned_bytes(fs_info, generic_ref);
+		add_pinned_bytes(fs_info, generic_ref, -1);
 
 	return ret;
 }
@@ -7176,7 +7178,7 @@ void btrfs_free_tree_block(struct btrfs_
 	}
 out:
 	if (pin)
-		add_pinned_bytes(fs_info, &generic_ref);
+		add_pinned_bytes(fs_info, &generic_ref, 1);
 
 	if (last_ref) {
 		/*
@@ -7219,7 +7221,7 @@ int btrfs_free_extent(struct btrfs_trans
 	}
 
 	if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0)
-		add_pinned_bytes(fs_info, ref);
+		add_pinned_bytes(fs_info, ref, 1);
 
 	return ret;
 }