• Amir Goldstein's avatar
    ovl: lookup index entry for copy up origin · 359f392c
    Amir Goldstein authored
    When inodes index feature is enabled, lookup in indexdir for the index
    entry of lower real inode or copy up origin inode. The index entry name
    is the hex representation of the lower inode file handle.
    
    If the index dentry in negative, then either no lower aliases have been
    copied up yet, or aliases have been copied up in older kernels and are
    not indexed.
    
    If the index dentry for a copy up origin inode is positive, but points
    to an inode different than the upper inode, then either the upper inode
    has been copied up and not indexed or it was indexed, but since then
    index dir was cleared. Either way, that index cannot be used to indentify
    the overlay inode.
    
    If a positive dentry that matches the upper inode was found, then it is
    safe to use the copy up origin st_ino for upper hardlinks, because all
    indexed upper hardlinks are represented by the same overlay inode as the
    copy up origin.
    
    Set the INDEX type flag on an indexed upper dentry. A non-upper dentry
    may also have a positive index from copy up of another lower hardlink.
    This situation will be handled by following patches.
    
    Index lookup is going to be used to prevent breaking hardlinks on copy up.
    Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
    Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
    359f392c
inode.c 12.2 KB