Ocfs2 devel - Apr 2015 - [PATCH 2/2] ocfs2_iop_set/get_acl() are also called from the VFS so we must take inode lock

Orabug: 20189959

This bug in mainline code is pointed out by Mark Fasheh. When ocfs2_iop_set_acl
and ocfs2_iop_ge_acl are entered from VFS layer, inode lock is not held. This
seems to be regression from older kernels. The patch is to fix that.

Signed-off-by: Tariq Saeed <tariq.x.saeed at oracle.com>
---
 fs/ocfs2/acl.c |   28 +++++++++++++++++++++-------
 1 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/fs/ocfs2/acl.c b/fs/ocfs2/acl.c
index 7e8282d..d7b5542 100644
--- a/fs/ocfs2/acl.c
+++ b/fs/ocfs2/acl.c
@@ -286,7 +286,19 @@ int ocfs2_set_acl(handle_t *handle,
 
 int ocfs2_iop_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 {
-	return ocfs2_set_acl(NULL, inode, NULL, type, acl, NULL, NULL);
+	struct buffer_head *bh = NULL;
+	int status = 0;
+
+	status = ocfs2_inode_lock(inode, &bh, 1);
+	if (status < 0) {
+		if (status != -ENOENT)
+			mlog_errno(status);
+		return status;
+	}
+	status = ocfs2_set_acl(NULL, inode, bh, type, acl, NULL, NULL);
+	ocfs2_inode_unlock(inode, 1);
+	brelse(bh);
+	return status;
 }
 
 struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type)
@@ -294,19 +306,21 @@ struct posix_acl *ocfs2_iop_get_acl(struct inode *inode,
int type)
 	struct ocfs2_super *osb;
 	struct buffer_head *di_bh = NULL;
 	struct posix_acl *acl;
-	int ret = -EAGAIN;
+	int ret;
 
 	osb = OCFS2_SB(inode->i_sb);
 	if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
 		return NULL;
-
-	ret = ocfs2_read_inode_block(inode, &di_bh);
-	if (ret < 0)
-		return ERR_PTR(ret);
+	ret = ocfs2_inode_lock(inode, &di_bh, 0);
+	if (ret < 0) {
+		mlog_errno(ret);
+		acl = ERR_PTR(ret);
+		return acl;
+	}
 
 	acl = ocfs2_get_acl_nolock(inode, type, di_bh);
 
+	ocfs2_inode_unlock(inode, 0);
 	brelse(di_bh);
-
 	return acl;
 }
-- 
1.7.1

Hi Tariq,

On 04/04/2015 05:46 AM, Tariq Saeed wrote:
> Orabug: 20189959
> 
> This bug in mainline code is pointed out by Mark Fasheh. When
ocfs2_iop_set_acl
> and ocfs2_iop_ge_acl are entered from VFS layer, inode lock is not held.
This
> seems to be regression from older kernels. The patch is to fix that.
> 
> Signed-off-by: Tariq Saeed <tariq.x.saeed at oracle.com>
> ---
>  fs/ocfs2/acl.c |   28 +++++++++++++++++++++-------
>  1 files changed, 21 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/ocfs2/acl.c b/fs/ocfs2/acl.c
> index 7e8282d..d7b5542 100644
> --- a/fs/ocfs2/acl.c
> +++ b/fs/ocfs2/acl.c
> @@ -286,7 +286,19 @@ int ocfs2_set_acl(handle_t *handle,
>  
>  int ocfs2_iop_set_acl(struct inode *inode, struct posix_acl *acl, int
type)
>  {
> -	return ocfs2_set_acl(NULL, inode, NULL, type, acl, NULL, NULL);
> +	struct buffer_head *bh = NULL;
> +	int status = 0;
> +
> +	status = ocfs2_inode_lock(inode, &bh, 1);
> +	if (status < 0) {
> +		if (status != -ENOENT)
> +			mlog_errno(status);
> +		return status;
> +	}
> +	status = ocfs2_set_acl(NULL, inode, bh, type, acl, NULL, NULL);
> +	ocfs2_inode_unlock(inode, 1);
> +	brelse(bh);
> +	return status;
>  }
>  
>  struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type)
> @@ -294,19 +306,21 @@ struct posix_acl *ocfs2_iop_get_acl(struct inode
*inode, int type)
>  	struct ocfs2_super *osb;
>  	struct buffer_head *di_bh = NULL;
>  	struct posix_acl *acl;
> -	int ret = -EAGAIN;
> +	int ret;
>  
>  	osb = OCFS2_SB(inode->i_sb);
>  	if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
>  		return NULL;
> -
> -	ret = ocfs2_read_inode_block(inode, &di_bh);
> -	if (ret < 0)
> -		return ERR_PTR(ret);
> +	ret = ocfs2_inode_lock(inode, &di_bh, 0);
> +	if (ret < 0) {
> +		mlog_errno(ret);
> +		acl = ERR_PTR(ret);
> +		return acl;
I think "return ERR_PTR(ret);" is more simple here.
Also why you check "status != -ENOENT" in ocfs2_iop_set_acl() but not
here?

Thanks,
Junxiao.
> +	}
>  
>  	acl = ocfs2_get_acl_nolock(inode, type, di_bh);
>  
> +	ocfs2_inode_unlock(inode, 0);
>  	brelse(di_bh);
> -
>  	return acl;
>  }
>