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

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

[Pujin Shi]

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 <shipujin.t@gmail.com>
---
 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

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

[Su Yue]

On Sat 03 Oct 2020 at 08:11, Pujin Shi <shipujin.t@gmail.com> 
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 <shipujin.t@gmail.com>
> ---
>  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;

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

[Nikolay Borisov]

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 <shipujin.t@gmail.com>

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;
>