2020-10-03 00:13:55

by Pujin Shi

Subject: [PATCH] fs: tree-checker: fix missing brace warning for old compilers

For older versions of gcc, the array = {0}; will cause warnings:

fs/btrfs/tree-checker.c: In function 'check_root_item':
fs/btrfs/tree-checker.c:1038:9: warning: missing braces around initializer [-Wmissing-braces]
struct btrfs_root_item ri = { 0 };
^
fs/btrfs/tree-checker.c:1038:9: warning: (near initialization for 'ri.inode') [-Wmissing-braces]

1 warnings generated

Fixes: 443b313c7ff8 ("btrfs: tree-checker: fix false alert caused by legacy btrfs root item")
Signed-off-by: Pujin Shi <[email protected]>
---
fs/btrfs/tree-checker.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index f0ffd5ee77bd..5028b3af308c 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -1035,7 +1035,7 @@ static int check_root_item(struct extent_buffer *leaf, struct btrfs_key *key,
int slot)
{
struct btrfs_fs_info *fs_info = leaf->fs_info;
- struct btrfs_root_item ri = { 0 };
+ struct btrfs_root_item ri = {};
const u64 valid_root_flags = BTRFS_ROOT_SUBVOL_RDONLY |
BTRFS_ROOT_SUBVOL_DEAD;
int ret;
--
2.18.1

2020-10-03 01:13:24

by Su Yue

Subject: Re: [PATCH] fs: tree-checker: fix missing brace warning for old compilers

On Sat 03 Oct 2020 at 08:11, Pujin Shi <[email protected]>
wrote:

> For older versions of gcc, the array = {0}; will cause warnings:
>
So what's the version number of the gcc? "struct foo = { 0 }"
should be
correct.

May be the compiler issue[1] related?

1: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53119


> fs/btrfs/tree-checker.c: In function 'check_root_item':
> fs/btrfs/tree-checker.c:1038:9: warning: missing braces around
> initializer [-Wmissing-braces]
> struct btrfs_root_item ri = { 0 };
> ^
> fs/btrfs/tree-checker.c:1038:9: warning: (near initialization
> for 'ri.inode') [-Wmissing-braces]
>
> 1 warnings generated
>
> Fixes: 443b313c7ff8 ("btrfs: tree-checker: fix false alert
> caused by legacy btrfs root item")
> Signed-off-by: Pujin Shi <[email protected]>
> ---
> fs/btrfs/tree-checker.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
> index f0ffd5ee77bd..5028b3af308c 100644
> --- a/fs/btrfs/tree-checker.c
> +++ b/fs/btrfs/tree-checker.c
> @@ -1035,7 +1035,7 @@ static int check_root_item(struct
> extent_buffer *leaf, struct btrfs_key *key,
> int slot)
> {
> struct btrfs_fs_info *fs_info = leaf->fs_info;
> - struct btrfs_root_item ri = { 0 };
> + struct btrfs_root_item ri = {};
> const u64 valid_root_flags = BTRFS_ROOT_SUBVOL_RDONLY |
> BTRFS_ROOT_SUBVOL_DEAD;
> int ret;

2020-10-03 08:08:05

by Nikolay Borisov

Subject: Re: [PATCH] fs: tree-checker: fix missing brace warning for old compilers

On 3.10.20 г. 3:11 ч., Pujin Shi wrote:
> For older versions of gcc, the array = {0}; will cause warnings:
>
> fs/btrfs/tree-checker.c: In function 'check_root_item':
> fs/btrfs/tree-checker.c:1038:9: warning: missing braces around initializer [-Wmissing-braces]
> struct btrfs_root_item ri = { 0 };
> ^
> fs/btrfs/tree-checker.c:1038:9: warning: (near initialization for 'ri.inode') [-Wmissing-braces]
>
> 1 warnings generated
>
> Fixes: 443b313c7ff8 ("btrfs: tree-checker: fix false alert caused by legacy btrfs root item")
> Signed-off-by: Pujin Shi <[email protected]>

This is a compiler artifact, please see:
http://www.ex-parrot.com/~chris/random/initialise.html

ALso having an empty initialization list like = {} while valid for gcc
is actually invalid according to the official standard. Check ISO C
Standard section 6.7.9 for the correct syntax of initializer-list.

IOW - NAK.

> ---
> fs/btrfs/tree-checker.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
> index f0ffd5ee77bd..5028b3af308c 100644
> --- a/fs/btrfs/tree-checker.c
> +++ b/fs/btrfs/tree-checker.c
> @@ -1035,7 +1035,7 @@ static int check_root_item(struct extent_buffer *leaf, struct btrfs_key *key,
> int slot)
> {
> struct btrfs_fs_info *fs_info = leaf->fs_info;
> - struct btrfs_root_item ri = { 0 };
> + struct btrfs_root_item ri = {};
> const u64 valid_root_flags = BTRFS_ROOT_SUBVOL_RDONLY |
> BTRFS_ROOT_SUBVOL_DEAD;
> int ret;
>