[PATCH] ext4: check eh_max before really insert index

[PATCH] ext4: check eh_max before really insert index

[Robin Dong]

Check eh_entries/eh_max before really insert index.

Signed-off-by: Robin Dong <sanbai@taobao.com>
---
 fs/ext4/extents.c |   18 ++++++++++--------
 1 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index eb63c7b..a742e6e 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -776,6 +776,16 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 				 logical, le32_to_cpu(curp->p_idx->ei_block));
 		return -EIO;
 	}
+
+	if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries) + 1
+			     > le16_to_cpu(curp->p_hdr->eh_max))) {
+		EXT4_ERROR_INODE(inode,
+				 "eh_entries %d + 1 > eh_max %d!",
+				 le16_to_cpu(curp->p_hdr->eh_entries),
+				 le16_to_cpu(curp->p_hdr->eh_max));
+		return -EIO;
+	}
+
 	len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
 	if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 		/* insert after */
@@ -805,14 +815,6 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 	ext4_idx_store_pblock(ix, ptr);
 	le16_add_cpu(&curp->p_hdr->eh_entries, 1);
 
-	if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
-			     > le16_to_cpu(curp->p_hdr->eh_max))) {
-		EXT4_ERROR_INODE(inode,
-				 "eh_entries %d > eh_max %d!",
-				 le16_to_cpu(curp->p_hdr->eh_entries),
-				 le16_to_cpu(curp->p_hdr->eh_max));
-		return -EIO;
-	}
 	if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
 		EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
 		return -EIO;
-- 
1.7.1

Re: [PATCH] ext4: check eh_max before really insert index

[Lukas Czerner]

On Wed, 22 Jun 2011, Robin Dong wrote:

> Check eh_entries/eh_max before really insert index.

Hi Robin,

thanks for the patch. Could you please describe why is the change
needed and what problem it fixes in the commit description. It is
not clear from the patch itself.

Thanks!
-Lukas

> 
> Signed-off-by: Robin Dong <sanbai@taobao.com>
> ---
>  fs/ext4/extents.c |   18 ++++++++++--------
>  1 files changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index eb63c7b..a742e6e 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -776,6 +776,16 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
>  				 logical, le32_to_cpu(curp->p_idx->ei_block));
>  		return -EIO;
>  	}
> +
> +	if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries) + 1
> +			     > le16_to_cpu(curp->p_hdr->eh_max))) {
> +		EXT4_ERROR_INODE(inode,
> +				 "eh_entries %d + 1 > eh_max %d!",
> +				 le16_to_cpu(curp->p_hdr->eh_entries),
> +				 le16_to_cpu(curp->p_hdr->eh_max));
> +		return -EIO;
> +	}
> +
>  	len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
>  	if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
>  		/* insert after */
> @@ -805,14 +815,6 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
>  	ext4_idx_store_pblock(ix, ptr);
>  	le16_add_cpu(&curp->p_hdr->eh_entries, 1);
>  
> -	if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
> -			     > le16_to_cpu(curp->p_hdr->eh_max))) {
> -		EXT4_ERROR_INODE(inode,
> -				 "eh_entries %d > eh_max %d!",
> -				 le16_to_cpu(curp->p_hdr->eh_entries),
> -				 le16_to_cpu(curp->p_hdr->eh_max));
> -		return -EIO;
> -	}
>  	if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
>  		EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
>  		return -EIO;
>