ovl: Add an inode flag OVL_CONST_INO

Add an ovl_inode flag OVL_CONST_INO.  This flag signifies if inode number
will remain constant over copy up or not.  This flag does not get updated
over copy up and remains unmodifed after setting once.

Next patch in the series will make use of this flag.  It will basically
figure out if dentry is of type ORIGIN or not.  And this can be derived by
this flag.

ORIGIN = (upperdentry && ovl_test_flag(OVL_CONST_INO, inode)).

Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 1255327..7c7092a 100644 (file)
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -883,6 +883,9 @@ struct inode *ovl_get_inode(struct super_block *sb,
 
        OVL_I(inode)->redirect = oip->redirect;
 
+       if (bylower)
+               ovl_set_flag(OVL_CONST_INO, inode);
+
        /* Check for non-merge dir that may have whiteouts */
        if (is_dir) {
                if (((upperdentry && lowerdentry) || oip->numlower > 1) ||

diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 99f7939..a6b466b 100644 (file)
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -38,6 +38,8 @@ enum ovl_inode_flag {
        OVL_WHITEOUTS,
        OVL_INDEX,
        OVL_UPPERDATA,
+       /* Inode number will remain constant over copy up. */
+       OVL_CONST_INO,
 };
 
 enum ovl_entry_flag {