From: Austin Kim <austindh.kim@gmail.com>
Date: Tue, 3 Sep 2019 12:30:19 +0900
Subject: btrfs: silence maybe-uninitialized warning in clone_range
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Git-commit: 431d39887d6273d6d84edf3c2eab09f4200e788a
Patch-mainline: 5.4-rc3
References: bnc#1151927 5.3.9

GCC throws warning message as below:

‘clone_src_i_size’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
 #define IS_ALIGNED(x, a)  (((x) & ((typeof(x))(a) - 1)) == 0)
                       ^
fs/btrfs/send.c:5088:6: note: ‘clone_src_i_size’ was declared here
 u64 clone_src_i_size;
   ^
The clone_src_i_size is only used as call-by-reference
in a call to get_inode_info().

Silence the warning by initializing clone_src_i_size to 0.

Note that the warning is a false positive and reported by older versions
of GCC (eg. 7.x) but not eg 9.x. As there have been numerous people, the
patch is applied. Setting clone_src_i_size to 0 does not otherwise make
sense and would not do any action in case the code changes in the future.

Signed-off-by: Austin Kim <austindh.kim@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add note ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 fs/btrfs/send.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index f3215028235c..123ac54af071 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -5085,7 +5085,7 @@ static int clone_range(struct send_ctx *sctx,
 	struct btrfs_path *path;
 	struct btrfs_key key;
 	int ret;
-	u64 clone_src_i_size;
+	u64 clone_src_i_size = 0;
 
 	/*
 	 * Prevent cloning from a zero offset with a length matching the sector
-- 
2.24.0