• Srinivas Eeda's avatar
    ocfs2: timer to queue scan of all orphan slots · 83273932
    Srinivas Eeda authored
    When a dentry is unlinked, the unlinking node takes an EX on the dentry lock
    before moving the dentry to the orphan directory. Other nodes that have
    this dentry in cache have a PR on the same dentry lock.  When the EX is
    requested, the other nodes flag the corresponding inode as MAYBE_ORPHANED
    during downconvert.  The inode is finally deleted when the last node to iput
    the inode sees that i_nlink==0 and the MAYBE_ORPHANED flag is set.
    
    A problem arises if a node is forced to free dentry locks because of memory
    pressure. If this happens, the node will no longer get downconvert
    notifications for the dentries that have been unlinked on another node.
    If it also happens that node is actively using the corresponding inode and
    happens to be the one performing the last iput on that inode, it will fail
    to delete the inode as it will not have the MAYBE_ORPHANED flag set.
    
    This patch fixes this shortcoming by introducing a periodic scan of the
    orphan directories to delete such inodes. Care has been taken to distribute
    the workload across the cluster so that no one node has to perform the task
    all the time.
    Signed-off-by: default avatarSrinivas Eeda <srinivas.eeda@oracle.com>
    Signed-off-by: default avatarJoel Becker <joel.becker@oracle.com>
    83273932
journal.h 20.3 KB