[PATCH v2 18/35] ovl: add lsattr/chattr support

From: Miklos Szeredi
Date: Mon May 07 2018 - 04:46:24 EST


Implement FS_IOC_GETFLAGS and FS_IOC_SETFLAGS.

Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
---
fs/overlayfs/file.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 79 insertions(+)

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 3a85bbfa266a..2028f6886649 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -8,6 +8,7 @@

#include <linux/cred.h>
#include <linux/file.h>
+#include <linux/mount.h>
#include <linux/xattr.h>
#include <linux/uio.h>
#include "overlayfs.h"
@@ -302,6 +303,82 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len
return ret;
}

+static long ovl_real_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct fd real;
+ const struct cred *old_cred;
+ long ret;
+
+ ret = ovl_real_fdget(file, &real);
+ if (ret)
+ return ret;
+
+ old_cred = ovl_override_creds(file_inode(file)->i_sb);
+ ret = vfs_ioctl(real.file, cmd, arg);
+ revert_creds(old_cred);
+
+ fdput(real);
+
+ return ret;
+}
+
+static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ long ret;
+ struct inode *inode = file_inode(file);
+
+ switch (cmd) {
+ case FS_IOC_GETFLAGS:
+ ret = ovl_real_ioctl(file, cmd, arg);
+ break;
+
+ case FS_IOC_SETFLAGS:
+ if (!inode_owner_or_capable(inode))
+ return -EACCES;
+
+ ret = mnt_want_write_file(file);
+ if (ret)
+ return ret;
+
+ ret = ovl_copy_up(file_dentry(file));
+ if (!ret) {
+ ret = ovl_real_ioctl(file, cmd, arg);
+
+ inode_lock(inode);
+ ovl_copyflags(ovl_inode_real(inode), inode);
+ inode_unlock(inode);
+ }
+
+ mnt_drop_write_file(file);
+ break;
+
+ default:
+ ret = -ENOTTY;
+ }
+
+ return ret;
+}
+
+static long ovl_compat_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ switch (cmd) {
+ case FS_IOC32_GETFLAGS:
+ cmd = FS_IOC_GETFLAGS;
+ break;
+
+ case FS_IOC32_SETFLAGS:
+ cmd = FS_IOC_SETFLAGS;
+ break;
+
+ default:
+ return -ENOIOCTLCMD;
+ }
+
+ return ovl_ioctl(file, cmd, arg);
+}
+
const struct file_operations ovl_file_operations = {
.open = ovl_open,
.release = ovl_release,
@@ -311,4 +388,6 @@ const struct file_operations ovl_file_operations = {
.fsync = ovl_fsync,
.mmap = ovl_mmap,
.fallocate = ovl_fallocate,
+ .unlocked_ioctl = ovl_ioctl,
+ .compat_ioctl = ovl_compat_ioctl,
};
--
2.14.3