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Commit 47cee541 authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by J. Bruce Fields
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nfsd: safer initialization order in find_file() 



The alloc_init_file() first adds a file to the hash and then
initializes its fi_inode, fi_id and fi_had_conflict.

The uninitialized fi_inode could thus be erroneously checked by
the find_file(), so move the hash insertion lower.

The client_mutex should prevent this race in practice; however, we
eventually hope to make less use of the client_mutex, so the ordering
here is an accident waiting to happen.

I didn't find whether the same can be true for two other fields,
but the common sense tells me it's better to initialize an object
before putting it into a global hash table :)

Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
Signed-off-by: default avatarJ. Bruce Fields <bfields@citi.umich.edu>
parent b7299f44

fs/nfsd/nfs4state.c

+3 −3
Original line number Diff line number Diff line
@@ -1757,12 +1757,12 @@ alloc_init_file(struct inode *ino) 
		INIT_LIST_HEAD(&fp->fi_hash);

		INIT_LIST_HEAD(&fp->fi_stateids);

		INIT_LIST_HEAD(&fp->fi_delegations);

		spin_lock(&recall_lock);

		list_add(&fp->fi_hash, &file_hashtbl[hashval]);

		spin_unlock(&recall_lock);

		fp->fi_inode = igrab(ino);

		fp->fi_id = current_fileid++;

		fp->fi_had_conflict = false;

		spin_lock(&recall_lock);

		list_add(&fp->fi_hash, &file_hashtbl[hashval]);

		spin_unlock(&recall_lock);

		return fp;

	}

	return NULL;