LOGICAL_INO v1 ignored the reserved fields, so they could be filled
with random stack garbage and have no effect. LOGICAL_INO_V2 requires
all unused reserved bits to be set to zero, and returns EINVAL if they
are not, to guard against future kernel versions which may interpret
non-zero bit values.
Sometimes when 'btrfs ins log' runs, the stack garbage is zeros, so the
-o (ignore offsets) option for logical-resolve works. Sometimes the
stack garbage is something else, and 'btrfs ins log -o' fails with
invalid argument. This depends mostly on compiler version and build
environment details, so a binary typically either always works or never
works.
Fix by initializing logical-resolve's argument structure with a C99
compound literal zero.
Signed-off-by: Zygo Blaxell <ce3g8jdj@xxxxxxxxxxxxxxxxxxxxx>
---
cmds/inspect.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/cmds/inspect.c b/cmds/inspect.c
index 9ca78611..5b946da0 100644
--- a/cmds/inspect.c
+++ b/cmds/inspect.c
@@ -149,7 +149,7 @@ static int cmd_inspect_logical_resolve(const struct cmd_struct *cmd,
int verbose = 0;
int getpath = 1;
int bytes_left;
- struct btrfs_ioctl_logical_ino_args loi;
+ struct btrfs_ioctl_logical_ino_args loi = { 0 };
struct btrfs_data_container *inodes;
u64 size = SZ_64K;
char full_path[PATH_MAX];
--
2.20.1
