From 7b0e492e6b80d51db4156996b248522c7b50d467 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@oracle.com>
Date: Mon, 1 Jul 2019 08:25:35 -0700
Subject: vfs: create a generic checking function for FS_IOC_FSSETXATTR

Create a generic checking function for the incoming FS_IOC_FSSETXATTR
fsxattr values so that we can standardize some of the implementation
behaviors.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/btrfs/ioctl.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

(limited to 'fs/btrfs/ioctl.c')

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index d3d9b4abb09b..3cd66efdb99d 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -375,9 +375,7 @@ static int btrfs_ioctl_fsgetxattr(struct file *file, void __user *arg)
 	struct btrfs_inode *binode = BTRFS_I(file_inode(file));
 	struct fsxattr fa;
 
-	memset(&fa, 0, sizeof(fa));
-	fa.fsx_xflags = btrfs_inode_flags_to_xflags(binode->flags);
-
+	simple_fill_fsxattr(&fa, btrfs_inode_flags_to_xflags(binode->flags));
 	if (copy_to_user(arg, &fa, sizeof(fa)))
 		return -EFAULT;
 
@@ -390,7 +388,7 @@ static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
 	struct btrfs_inode *binode = BTRFS_I(inode);
 	struct btrfs_root *root = binode->root;
 	struct btrfs_trans_handle *trans;
-	struct fsxattr fa;
+	struct fsxattr fa, old_fa;
 	unsigned old_flags;
 	unsigned old_i_flags;
 	int ret = 0;
@@ -401,7 +399,6 @@ static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
 	if (btrfs_root_readonly(root))
 		return -EROFS;
 
-	memset(&fa, 0, sizeof(fa));
 	if (copy_from_user(&fa, arg, sizeof(fa)))
 		return -EFAULT;
 
@@ -421,13 +418,11 @@ static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
 	old_flags = binode->flags;
 	old_i_flags = inode->i_flags;
 
-	/* We need the capabilities to change append-only or immutable inode */
-	if (((old_flags & (BTRFS_INODE_APPEND | BTRFS_INODE_IMMUTABLE)) ||
-	     (fa.fsx_xflags & (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE))) &&
-	    !capable(CAP_LINUX_IMMUTABLE)) {
-		ret = -EPERM;
+	simple_fill_fsxattr(&old_fa,
+			    btrfs_inode_flags_to_xflags(binode->flags));
+	ret = vfs_ioc_fssetxattr_check(inode, &old_fa, &fa);
+	if (ret)
 		goto out_unlock;
-	}
 
 	if (fa.fsx_xflags & FS_XFLAG_SYNC)
 		binode->flags |= BTRFS_INODE_SYNC;
-- 
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