[PATCH] nilfs2: move initialization of nr_dirty to decl

[PATCH] nilfs2: move initialization of nr_dirty to decl

[trix-H+wXaHxf7aLQT0dZR+AlfA]

From: Tom Rix <trix-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

On clang build there is this error
inode.c:227:13: error: variable 'nr_dirty' is
  used uninitialized whenever 'if' condition is false
        } else if (ret) {
                   ^~~

In nilfs_dirty_folio(), if the call to
filemap_dirty_folio() fails and there
are no buffers, nr_dirty will be uninitialized.
Move the initialization out of the buffer
block and to the decl.

Signed-off-by: Tom Rix <trix-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 fs/nilfs2/inode.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index c1219c0678a57..01e58b65c9384 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -204,7 +204,7 @@ static bool nilfs_dirty_folio(struct address_space *mapping,
 {
 	struct inode *inode = mapping->host;
 	struct buffer_head *head;
-	unsigned int nr_dirty;
+	unsigned int nr_dirty = 0;
 	bool ret = filemap_dirty_folio(mapping, folio);
 
 	/*
@@ -214,8 +214,6 @@ static bool nilfs_dirty_folio(struct address_space *mapping,
 	head = folio_buffers(folio);
 	if (head) {
 		struct buffer_head *bh = head;
-
-		nr_dirty = 0;
 		do {
 			/* Do not mark hole blocks dirty */
 			if (buffer_dirty(bh) || !buffer_mapped(bh))
-- 
2.26.3

Re: [PATCH] nilfs2: move initialization of nr_dirty to decl

[Nathan Chancellor]

Hi Tom,

On Thu, Mar 17, 2022 at 10:50:43AM -0700, trix-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org wrote:
> From: Tom Rix <trix-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> 
> On clang build there is this error
> inode.c:227:13: error: variable 'nr_dirty' is
>   used uninitialized whenever 'if' condition is false
>         } else if (ret) {
>                    ^~~
> 
> In nilfs_dirty_folio(), if the call to
> filemap_dirty_folio() fails and there
> are no buffers, nr_dirty will be uninitialized.
> Move the initialization out of the buffer
> block and to the decl.
> 
> Signed-off-by: Tom Rix <trix-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

This has been fixed in next-20220317:

https://git.kernel.org/next/linux-next/c/af7afdc7bbbe60cb6ce51a86b022d647e1a72717

Cheers,
Nathan

> ---
>  fs/nilfs2/inode.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
> index c1219c0678a57..01e58b65c9384 100644
> --- a/fs/nilfs2/inode.c
> +++ b/fs/nilfs2/inode.c
> @@ -204,7 +204,7 @@ static bool nilfs_dirty_folio(struct address_space *mapping,
>  {
>  	struct inode *inode = mapping->host;
>  	struct buffer_head *head;
> -	unsigned int nr_dirty;
> +	unsigned int nr_dirty = 0;
>  	bool ret = filemap_dirty_folio(mapping, folio);
>  
>  	/*
> @@ -214,8 +214,6 @@ static bool nilfs_dirty_folio(struct address_space *mapping,
>  	head = folio_buffers(folio);
>  	if (head) {
>  		struct buffer_head *bh = head;
> -
> -		nr_dirty = 0;
>  		do {
>  			/* Do not mark hole blocks dirty */
>  			if (buffer_dirty(bh) || !buffer_mapped(bh))
> -- 
> 2.26.3
>