[PATCH] quota: check quota type in early stage

[PATCH] quota: check quota type in early stage

[Chengguang Xu]

Check quota type in early stage so we can avoid many
unncessary operations when the type is wrong.

Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
---
 fs/quota/quota.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index cb13fb76dbee..5444d3c4d93f 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -60,8 +60,6 @@ static int quota_sync_all(int type)
 {
 	int ret;
 
-	if (type >= MAXQUOTAS)
-		return -EINVAL;
 	ret = security_quotactl(Q_SYNC, type, 0, NULL);
 	if (!ret)
 		iterate_supers(quota_sync_one, &type);
@@ -686,8 +684,6 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
 {
 	int ret;
 
-	if (type >= MAXQUOTAS)
-		return -EINVAL;
 	type = array_index_nospec(type, MAXQUOTAS);
 	/*
 	 * Quota not supported on this fs? Check this before s_quota_types
@@ -831,6 +827,9 @@ int kernel_quotactl(unsigned int cmd, const char __user *special,
 	cmds = cmd >> SUBCMDSHIFT;
 	type = cmd & SUBCMDMASK;
 
+	if (type >= MAXQUOTAS)
+		return -EINVAL;
+
 	/*
 	 * As a special case Q_SYNC can be called without a specific device.
 	 * It will iterate all superblocks that have quota enabled and call
-- 
2.21.0

Re: [PATCH] quota: check quota type in early stage

[Jan Kara]

On Tue 08-10-19 22:50:59, Chengguang Xu wrote:
> Check quota type in early stage so we can avoid many
> unncessary operations when the type is wrong.
> 
> Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>

Yeah, checking earlier makes sense, especially since it consolidates two
checks into one. I've added your patch to my tree. Thanks!

								Honza

> ---
>  fs/quota/quota.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/quota/quota.c b/fs/quota/quota.c
> index cb13fb76dbee..5444d3c4d93f 100644
> --- a/fs/quota/quota.c
> +++ b/fs/quota/quota.c
> @@ -60,8 +60,6 @@ static int quota_sync_all(int type)
>  {
>  	int ret;
>  
> -	if (type >= MAXQUOTAS)
> -		return -EINVAL;
>  	ret = security_quotactl(Q_SYNC, type, 0, NULL);
>  	if (!ret)
>  		iterate_supers(quota_sync_one, &type);
> @@ -686,8 +684,6 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
>  {
>  	int ret;
>  
> -	if (type >= MAXQUOTAS)
> -		return -EINVAL;
>  	type = array_index_nospec(type, MAXQUOTAS);
>  	/*
>  	 * Quota not supported on this fs? Check this before s_quota_types
> @@ -831,6 +827,9 @@ int kernel_quotactl(unsigned int cmd, const char __user *special,
>  	cmds = cmd >> SUBCMDSHIFT;
>  	type = cmd & SUBCMDMASK;
>  
> +	if (type >= MAXQUOTAS)
> +		return -EINVAL;
> +
>  	/*
>  	 * As a special case Q_SYNC can be called without a specific device.
>  	 * It will iterate all superblocks that have quota enabled and call
> -- 
> 2.21.0
> 
> 
> 
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR