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NFS: teach nfs_neg_need_reval to understand LOOKUP_RCU

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This requires nfs_check_verifier to take an rcu_walk flag, and requires
an rcu version of nfs_revalidate_inode which returns -ECHILD rather
than making an RPC call.

With this, nfs_lookup_revalidate can call nfs_neg_need_reval in
RCU-walk mode.

We can also move the LOOKUP_RCU check past the nfs_check_verifier()
call in nfs_lookup_revalidate.

If RCU_WALK prevents nfs_check_verifier or nfs_neg_need_reval from
doing a full check, they return a status indicating that a revalidation
is required.  As this revalidation will not be possible in RCU_WALK
mode, -ECHILD will ultimately be returned, which is the desired result.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
NeilBrown
2014-07-14 11:28:20 +10:00
committed by Trond Myklebust
parent f3324a2a94
commit 912a108da7
3 changed files with 52 additions and 17 deletions
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9
fs/nfs/inode.c
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@@ -1002,6 +1002,15 @@ int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
}
EXPORT_SYMBOL_GPL(nfs_revalidate_inode);
int nfs_revalidate_inode_rcu(struct nfs_server *server, struct inode *inode)
{
if (!(NFS_I(inode)->cache_validity &
(NFS_INO_INVALID_ATTR|NFS_INO_INVALID_LABEL))
&& !nfs_attribute_cache_expired(inode))
return NFS_STALE(inode) ? -ESTALE : 0;
return -ECHILD;
}
static int nfs_invalidate_mapping(struct inode *inode, struct address_space *mapping)
{
struct nfs_inode *nfsi = NFS_I(inode);