vfs: create a generic checking and prep function for FS_IOC_SETFLAGS

Create a generic function to check incoming FS_IOC_SETFLAGS flag values
and later prepare the inode for updates so that we can standardize the
implementations that follow ext4's flag values.

Note that the efivarfs implementation no longer fails a no-op SETFLAGS
without CAP_LINUX_IMMUTABLE since that's the behavior in ext*.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: David Sterba <dsterba@suse.com>
Reviewed-by: Bob Peterson <rpeterso@redhat.com>

1 files changed, 4 insertions, 12 deletions

diff --git a/fs/ext2/ioctl.c b/fs/ext2/ioctl.c
index 0367c0039e68..1b853fb0b163 100644
--- a/fs/ext2/ioctl.c
+++ b/fs/ext2/ioctl.c
@@ -60,18 +60,10 @@ long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		}
 		oldflags = ei->i_flags;
 
-		/*
-		 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
-		 * the relevant capability.
-		 *
-		 * This test looks nicer. Thanks to Pauline Middelink
-		 */
-		if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
-			if (!capable(CAP_LINUX_IMMUTABLE)) {
-				inode_unlock(inode);
-				ret = -EPERM;
-				goto setflags_out;
-			}
+		ret = vfs_ioc_setflags_prepare(inode, oldflags, flags);
+		if (ret) {
+			inode_unlock(inode);
+			goto setflags_out;
 		}
 
 		flags = flags & EXT2_FL_USER_MODIFIABLE;