[PATCH] ext4: ext4_mb_mark_free_simple: Fix integer value truncation

[PATCH] ext4: ext4_mb_mark_free_simple: Fix integer value truncation

[Chandan Rajendra]

'border' variable is set to a value of 2 times the block size of the
underlying filesystem. With 64k block size, the resulting value won't
fit into a 16-bit variable. Hence this commit changes the data type of
'border' to 'unsigned int'.

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
 fs/ext4/mballoc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index f418f55..a937ac7 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -669,7 +669,7 @@ static void ext4_mb_mark_free_simple(struct super_block *sb,
 	ext4_grpblk_t min;
 	ext4_grpblk_t max;
 	ext4_grpblk_t chunk;
-	unsigned short border;
+	unsigned int border;
 
 	BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
 
-- 
2.5.5

[PATCH] ext4: ext4_mb_mark_free_simple: Fix integer value truncation

[Chandan Rajendra]

'border' variable is set to a value of 2 times the block size of the
underlying filesystem. With 64k block size, the resulting value won't
fit into a 16-bit variable. Hence this commit changes the data type of
'border' to 'unsigned int'.

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
 fs/ext4/mballoc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index f418f55..a937ac7 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -669,7 +669,7 @@ static void ext4_mb_mark_free_simple(struct super_block *sb,
 	ext4_grpblk_t min;
 	ext4_grpblk_t max;
 	ext4_grpblk_t chunk;
-	unsigned short border;
+	unsigned int border;
 
 	BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
 
-- 
2.5.5

Re: [PATCH] ext4: ext4_mb_mark_free_simple: Fix integer value truncation

[Andreas Dilger]

[-- Attachment #1: Type: text/plain, Size: 1206 bytes --]

On Nov 3, 2016, at 3:14 AM, Chandan Rajendra <chandan@linux.vnet.ibm.com> wrote:
> 
> 'border' variable is set to a value of 2 times the block size of the
> underlying filesystem. With 64k block size, the resulting value won't
> fit into a 16-bit variable. Hence this commit changes the data type of
> 'border' to 'unsigned int'.
> 
> Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>

Reviewed-by: Andreas Dilger <adilger@dilger.ca>

> ---
> fs/ext4/mballoc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index f418f55..a937ac7 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -669,7 +669,7 @@ static void ext4_mb_mark_free_simple(struct super_block *sb,
> 	ext4_grpblk_t min;
> 	ext4_grpblk_t max;
> 	ext4_grpblk_t chunk;
> -	unsigned short border;
> +	unsigned int border;
> 
> 	BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
> 
> --
> 2.5.5
> 
> --
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Cheers, Andreas






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Re: [PATCH] ext4: ext4_mb_mark_free_simple: Fix integer value truncation

[Theodore Ts'o]

On Thu, Nov 03, 2016 at 01:32:33PM -0600, Andreas Dilger wrote:
> On Nov 3, 2016, at 3:14 AM, Chandan Rajendra <chandan@linux.vnet.ibm.com> wrote:
> > 
> > 'border' variable is set to a value of 2 times the block size of the
> > underlying filesystem. With 64k block size, the resulting value won't
> > fit into a 16-bit variable. Hence this commit changes the data type of
> > 'border' to 'unsigned int'.
> > 
> > Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
> 
> Reviewed-by: Andreas Dilger <adilger@dilger.ca>

Applied, with a change in the commit summary:

    ext4: fix mballoc breakage with 64k block size

Many thanks!!

					- Ted