[PATCH] nilfs2: Add pointer check for nilfs_direct_propagate()

[Wentao Liang <vulab@iscas.ac.cn>]

In nilfs_direct_propagate(), the printer get from nilfs_direct_get_ptr()
need to be checked to ensure it is not an invalid pointer. A proper
implementation can be found in nilfs_direct_delete(). Add a value check
and return -ENOENT when it is an invalid pointer.

Fixes: 10ff885ba6f5 ("nilfs2: get rid of nilfs_direct uses")
Cc: stable@vger.kernel.org # v2.6+
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
---
 fs/nilfs2/direct.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/nilfs2/direct.c b/fs/nilfs2/direct.c
index 893ab36824cc..ff1c9fe72bec 100644
--- a/fs/nilfs2/direct.c
+++ b/fs/nilfs2/direct.c
@@ -273,6 +273,9 @@ static int nilfs_direct_propagate(struct nilfs_bmap *bmap,
 	dat = nilfs_bmap_get_dat(bmap);
 	key = nilfs_bmap_data_get_key(bmap, bh);
 	ptr = nilfs_direct_get_ptr(bmap, key);
+	if (ptr == NILFS_BMAP_INVALID_PTR)
+		return -ENOENT;
+
 	if (!buffer_nilfs_volatile(bh)) {
 		oldreq.pr_entry_nr = ptr;
 		newreq.pr_entry_nr = ptr;
-- 
2.42.0.windows.2