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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dan Carpenter <dan.carpenter@oracle.com>,
        David Sterba <dsterba@suse.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 196/219] btrfs: return error pointer from alloc_test_extent_buffer
Date:   Sun, 29 Dec 2019 18:19:58 +0100
Message-Id: <20191229162539.453938271@linuxfoundation.org>
In-Reply-To: <20191229162508.458551679@linuxfoundation.org>
References: <20191229162508.458551679@linuxfoundation.org>
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From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit b6293c821ea8fa2a631a2112cd86cd435effeb8b ]

Callers of alloc_test_extent_buffer have not correctly interpreted the
return value as error pointer, as alloc_test_extent_buffer should behave
as alloc_extent_buffer. The self-tests were unaffected but
btrfs_find_create_tree_block could call both functions and that would
cause problems up in the call chain.

Fixes: faa2dbf004e8 ("Btrfs: add sanity tests for new qgroup accounting code")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/btrfs/extent_io.c                   | 6 ++++--
 fs/btrfs/tests/free-space-tree-tests.c | 4 ++--
 fs/btrfs/tests/qgroup-tests.c          | 4 ++--
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 88fc5a0c573f..fed44390c049 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4888,12 +4888,14 @@ struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
 		return eb;
 	eb = alloc_dummy_extent_buffer(fs_info, start);
 	if (!eb)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	eb->fs_info = fs_info;
 again:
 	ret = radix_tree_preload(GFP_NOFS);
-	if (ret)
+	if (ret) {
+		exists = ERR_PTR(ret);
 		goto free_eb;
+	}
 	spin_lock(&fs_info->buffer_lock);
 	ret = radix_tree_insert(&fs_info->buffer_radix,
 				start >> PAGE_SHIFT, eb);
diff --git a/fs/btrfs/tests/free-space-tree-tests.c b/fs/btrfs/tests/free-space-tree-tests.c
index 89346da890cf..de8fef91ac48 100644
--- a/fs/btrfs/tests/free-space-tree-tests.c
+++ b/fs/btrfs/tests/free-space-tree-tests.c
@@ -462,9 +462,9 @@ static int run_test(test_func_t test_func, int bitmaps, u32 sectorsize,
 	root->fs_info->tree_root = root;
 
 	root->node = alloc_test_extent_buffer(root->fs_info, nodesize);
-	if (!root->node) {
+	if (IS_ERR(root->node)) {
 		test_err("couldn't allocate dummy buffer");
-		ret = -ENOMEM;
+		ret = PTR_ERR(root->node);
 		goto out;
 	}
 	btrfs_set_header_level(root->node, 0);
diff --git a/fs/btrfs/tests/qgroup-tests.c b/fs/btrfs/tests/qgroup-tests.c
index 412b910b04cc..d07dd26194b1 100644
--- a/fs/btrfs/tests/qgroup-tests.c
+++ b/fs/btrfs/tests/qgroup-tests.c
@@ -484,9 +484,9 @@ int btrfs_test_qgroups(u32 sectorsize, u32 nodesize)
 	 * *cough*backref walking code*cough*
 	 */
 	root->node = alloc_test_extent_buffer(root->fs_info, nodesize);
-	if (!root->node) {
+	if (IS_ERR(root->node)) {
 		test_err("couldn't allocate dummy buffer");
-		ret = -ENOMEM;
+		ret = PTR_ERR(root->node);
 		goto out;
 	}
 	btrfs_set_header_level(root->node, 0);
-- 
2.20.1