On Tue, 2016-05-17 at 23:53 +0200, Miklos Szeredi wrote: > The two methods essentially do the same: find the real dentry/inode > belonging to an overlay dentry. The difference is in the usage: > > vfs_open() uses ->d_select_inode() and expects the function to > perform copy-up if necessary based on the open flags argument. > > file_dentry() uses ->d_real() passing in the overlay dentry as well > as the underlying inode. > > vfs_rename() uses ->d_select_inode() but passes zero flags. > ->d_real() with a zero inode would have worked just as well here. > > This patch merges the functionality of ->d_select_inode() into > ->d_real() by adding an 'open_flags' argument to the latter. Actually, before you do this, I have a use case for keeping them separate: The shiftfs prototype I've posted cannot use d_select_inode because it's shifting the uid/gids, so the inode permissions have to be done on the upper inode. However, several filesystems make use of file_dentry() and for them, I need to supply the lower dentry, so I end up setting d_real but not d_select_inode. for me, then vfs_open and vfs_rename have to operate on the upper inode but all uses of file_dentry should return the lower dentry. James -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
