linux-kernel - [PATCH 03/18] ovl: stack miscattr

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Message-Id: <20210203124112.1182614-4-mszeredi@redhat.com>
Date:   Wed,  3 Feb 2021 13:40:57 +0100
From:   Miklos Szeredi <mszeredi@...hat.com>
To:     linux-fsdevel@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH 03/18] ovl: stack miscattr

Add stacking for the miscattr operations.

Signed-off-by: Miklos Szeredi <mszeredi@...hat.com>
---
 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); */
+		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