[PATCH] fs: btrfs: Add an assertion to warn incorrct case in insert_inline_extent()

[Jia-Ju Bai]

In insert_inline_extent(), the case that compressed_size > 0 
and compressed_pages = NULL cannot occur, otherwise a null-pointer
dereference may occur on line 215:
     cpage = compressed_pages[i];

To warn this incorrect case, an assertion is added.
Thank Qu Wenruo and David Sterba for good advice.

Signed-off-by: Jia-Ju Bai <baijiaju1...@gmail.com>
---
 fs/btrfs/inode.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 1af069a9a0c7..21d6e2dcc25f 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -178,6 +178,9 @@ static int insert_inline_extent(struct btrfs_trans_handle 
*trans,
        size_t cur_size = size;
        unsigned long offset;
 
+       ASSERT((compressed_size > 0 && compressed_pages) ||
+                       (compressed_size == 0 && !compressed_pages))
+
        if (compressed_size && compressed_pages)
                cur_size = compressed_size;
 
-- 
2.17.0