Re: [PATCH 03/18] ovl: stack miscattr

From: Vivek Goyal
Date: Thu Feb 04 2021 - 18:45:15 EST


On Wed, Feb 03, 2021 at 01:40:57PM +0100, Miklos Szeredi wrote:
> Add stacking for the miscattr operations.
>
> Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
> ---
> fs/overlayfs/dir.c | 2 ++
> fs/overlayfs/inode.c | 43 ++++++++++++++++++++++++++++++++++++++++
> fs/overlayfs/overlayfs.h | 2 ++
> 3 files changed, 47 insertions(+)
>
> diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
> index 28a075b5f5b2..77c6b44f8d83 100644
> --- a/fs/overlayfs/dir.c
> +++ b/fs/overlayfs/dir.c
> @@ -1300,4 +1300,6 @@ const struct inode_operations ovl_dir_inode_operations = {
> .listxattr = ovl_listxattr,
> .get_acl = ovl_get_acl,
> .update_time = ovl_update_time,
> + .miscattr_get = ovl_miscattr_get,
> + .miscattr_set = ovl_miscattr_set,
> };
> diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
> index d739e14c6814..97d36d1f28c3 100644
> --- a/fs/overlayfs/inode.c
> +++ b/fs/overlayfs/inode.c
> @@ -11,6 +11,7 @@
> #include <linux/posix_acl.h>
> #include <linux/ratelimit.h>
> #include <linux/fiemap.h>
> +#include <linux/miscattr.h>
> #include "overlayfs.h"
>
>
> @@ -495,6 +496,46 @@ static int ovl_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
> return err;
> }
>
> +int ovl_miscattr_set(struct dentry *dentry, struct miscattr *ma)
> +{
> + struct inode *inode = d_inode(dentry);
> + struct dentry *upperdentry;
> + const struct cred *old_cred;
> + int err;
> +
> + err = ovl_want_write(dentry);
> + if (err)
> + goto out;
> +
> + err = ovl_copy_up(dentry);
> + if (!err) {
> + upperdentry = ovl_dentry_upper(dentry);
> +
> + old_cred = ovl_override_creds(inode->i_sb);
> + /* err = security_file_ioctl(real.file, cmd, arg); */

Is this an comment intended?

Vivek

> + err = vfs_miscattr_set(upperdentry, ma);
> + revert_creds(old_cred);
> + ovl_copyflags(ovl_inode_real(inode), inode);
> + }
> + ovl_drop_write(dentry);
> +out:
> + return err;
> +}
> +
> +int ovl_miscattr_get(struct dentry *dentry, struct miscattr *ma)
> +{
> + struct inode *inode = d_inode(dentry);
> + struct dentry *realdentry = ovl_dentry_real(dentry);
> + const struct cred *old_cred;
> + int err;
> +
> + old_cred = ovl_override_creds(inode->i_sb);
> + err = vfs_miscattr_get(realdentry, ma);
> + revert_creds(old_cred);
> +
> + return err;
> +}
> +
> static const struct inode_operations ovl_file_inode_operations = {
> .setattr = ovl_setattr,
> .permission = ovl_permission,
> @@ -503,6 +544,8 @@ static const struct inode_operations ovl_file_inode_operations = {
> .get_acl = ovl_get_acl,
> .update_time = ovl_update_time,
> .fiemap = ovl_fiemap,
> + .miscattr_get = ovl_miscattr_get,
> + .miscattr_set = ovl_miscattr_set,
> };
>
> static const struct inode_operations ovl_symlink_inode_operations = {
> diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
> index b487e48c7fd4..d3ad02c34cca 100644
> --- a/fs/overlayfs/overlayfs.h
> +++ b/fs/overlayfs/overlayfs.h
> @@ -509,6 +509,8 @@ int __init ovl_aio_request_cache_init(void);
> void ovl_aio_request_cache_destroy(void);
> long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
> long ovl_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
> +int ovl_miscattr_get(struct dentry *dentry, struct miscattr *ma);
> +int ovl_miscattr_set(struct dentry *dentry, struct miscattr *ma);
>
> /* copy_up.c */
> int ovl_copy_up(struct dentry *dentry);
> --
> 2.26.2
>