diff --git a/fs/nfs_common/nfslocalio.c b/fs/nfs_common/nfslocalio.c index 09404d142d1a..a74ec08f6c96 100644 --- a/fs/nfs_common/nfslocalio.c +++ b/fs/nfs_common/nfslocalio.c @@ -155,11 +155,9 @@ struct nfsd_file *nfs_open_local_fh(nfs_uuid_t *uuid, /* We have an implied reference to net thanks to nfsd_serv_try_get */ localio = nfs_to->nfsd_open_local_fh(net, uuid->dom, rpc_clnt, cred, nfs_fh, fmode); - if (IS_ERR(localio)) { - rcu_read_lock(); - nfs_to->nfsd_serv_put(net); - rcu_read_unlock(); - } + if (IS_ERR(localio)) + nfs_to_nfsd_net_put(net); + return localio; } EXPORT_SYMBOL_GPL(nfs_open_local_fh); diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index c16671135d17..9a62b4da89bb 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -391,19 +391,19 @@ nfsd_file_put(struct nfsd_file *nf) } /** - * nfsd_file_put_local - put the reference to nfsd_file and local nfsd_serv - * @nf: nfsd_file of which to put the references + * nfsd_file_put_local - put nfsd_file reference and arm nfsd_serv_put in caller + * @nf: nfsd_file of which to put the reference * - * First put the reference of the nfsd_file and then put the - * reference to the associated nn->nfsd_serv. + * First save the associated net to return to caller, then put + * the reference of the nfsd_file. */ -void -nfsd_file_put_local(struct nfsd_file *nf) __must_hold(rcu) +struct net * +nfsd_file_put_local(struct nfsd_file *nf) { struct net *net = nf->nf_net; nfsd_file_put(nf); - nfsd_serv_put(net); + return net; } /** diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h index cadf3c2689c4..d5db6b34ba30 100644 --- a/fs/nfsd/filecache.h +++ b/fs/nfsd/filecache.h @@ -55,7 +55,7 @@ void nfsd_file_cache_shutdown(void); int nfsd_file_cache_start_net(struct net *net); void nfsd_file_cache_shutdown_net(struct net *net); void nfsd_file_put(struct nfsd_file *nf); -void nfsd_file_put_local(struct nfsd_file *nf); +struct net *nfsd_file_put_local(struct nfsd_file *nf); struct nfsd_file *nfsd_file_get(struct nfsd_file *nf); struct file *nfsd_file_file(struct nfsd_file *nf); void nfsd_file_close_inode_sync(struct inode *inode); diff --git a/include/linux/nfslocalio.h b/include/linux/nfslocalio.h index 3982fea79919..9202f4b24343 100644 --- a/include/linux/nfslocalio.h +++ b/include/linux/nfslocalio.h @@ -55,7 +55,7 @@ struct nfsd_localio_operations { const struct cred *, const struct nfs_fh *, const fmode_t); - void (*nfsd_file_put_local)(struct nfsd_file *); + struct net *(*nfsd_file_put_local)(struct nfsd_file *); struct file *(*nfsd_file_file)(struct nfsd_file *); } ____cacheline_aligned; @@ -66,7 +66,7 @@ struct nfsd_file *nfs_open_local_fh(nfs_uuid_t *, struct rpc_clnt *, const struct cred *, const struct nfs_fh *, const fmode_t); -static inline void nfs_to_nfsd_file_put_local(struct nfsd_file *localio) +static inline void nfs_to_nfsd_net_put(struct net *net) { /* * Once reference to nfsd_serv is dropped, NFSD could be @@ -74,10 +74,22 @@ static inline void nfs_to_nfsd_file_put_local(struct nfsd_file *localio) * by always taking RCU. */ rcu_read_lock(); - nfs_to->nfsd_file_put_local(localio); + nfs_to->nfsd_serv_put(net); rcu_read_unlock(); } +static inline void nfs_to_nfsd_file_put_local(struct nfsd_file *localio) +{ + /* + * Must not hold RCU otherwise nfsd_file_put() can easily trigger: + * "Voluntary context switch within RCU read-side critical section!" + * by scheduling deep in underlying filesystem (e.g. XFS). + */ + struct net *net = nfs_to->nfsd_file_put_local(localio); + + nfs_to_nfsd_net_put(net); +} + #else /* CONFIG_NFS_LOCALIO */ static inline void nfsd_localio_ops_init(void) {