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    VFS: Fix the nfs sillyrename regression in kernel 2.6.38 · c83ce989
    Trond Myklebust 提交于
    The new vfs locking scheme introduced in 2.6.38 breaks NFS sillyrename
    because the latter relies on being able to determine the parent
    directory of the dentry in the ->iput() callback in order to send the
    appropriate unlink rpc call.
    
    Looking at the code that cares about races with dput(), there doesn't
    seem to be anything that specifically uses d_parent as a test for
    whether or not there is a race:
      - __d_lookup_rcu(), __d_lookup() all test for d_hashed() after d_parent
      - shrink_dcache_for_umount() is safe since nothing else can rearrange
        the dentries in that super block.
      - have_submount(), select_parent() and d_genocide() can test for a
        deletion if we set the DCACHE_DISCONNECTED flag when the dentry
        is removed from the parent's d_subdirs list.
    Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
    Cc: stable@kernel.org (2.6.38, needs commit c826cb7d "dcache.c:
    	create helper function for duplicated functionality" )
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    c83ce989
dcache.c 78.2 KB