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nfsd: add nfsd_file_acquire_local()
nfsd_file_acquire_local() can be used to look up a file by filehandle without having a struct svc_rqst. This can be used by NFS LOCALIO to allow the NFS client to bypass the NFS protocol to directly access a file provided by the NFS server which is running in the same kernel. In nfsd_file_do_acquire() care is taken to always use fh_verify() if rqstp is not NULL (as is the case for non-LOCALIO callers). Otherwise the non-LOCALIO callers will not supply the correct and required arguments to __fh_verify (e.g. gssclient isn't passed). Introduce fh_verify_local() wrapper around __fh_verify to make it clear that LOCALIO is intended caller. Also, use GC for nfsd_file returned by nfsd_file_acquire_local. GC offers performance improvements if/when a file is reopened before launderette cleans it from the filecache's LRU. Suggested-by: Jeff Layton <jlayton@kernel.org> # use filecache's GC Signed-off-by: NeilBrown <neilb@suse.de> Co-developed-by: Mike Snitzer <snitzer@kernel.org> Signed-off-by: Mike Snitzer <snitzer@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
This commit is contained in:
NeilBrown
Anna Schumaker
parent
5e66d2d92a
commit
c63f0e48fe
@ -982,12 +982,14 @@ nfsd_file_is_cached(struct inode *inode)
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}
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static __be32
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nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
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nfsd_file_do_acquire(struct svc_rqst *rqstp, struct net *net,
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struct svc_cred *cred,
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struct auth_domain *client,
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struct svc_fh *fhp,
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unsigned int may_flags, struct file *file,
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struct nfsd_file **pnf, bool want_gc)
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{
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unsigned char need = may_flags & NFSD_FILE_MAY_MASK;
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struct net *net = SVC_NET(rqstp);
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struct nfsd_file *new, *nf;
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bool stale_retry = true;
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bool open_retry = true;
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@ -996,8 +998,13 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
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int ret;
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retry:
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if (rqstp) {
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status = fh_verify(rqstp, fhp, S_IFREG,
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may_flags|NFSD_MAY_OWNER_OVERRIDE);
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} else {
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status = fh_verify_local(net, cred, client, fhp, S_IFREG,
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may_flags|NFSD_MAY_OWNER_OVERRIDE);
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}
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if (status != nfs_ok)
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return status;
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inode = d_inode(fhp->fh_dentry);
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@ -1143,7 +1150,8 @@ __be32
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nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,
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unsigned int may_flags, struct nfsd_file **pnf)
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{
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return nfsd_file_do_acquire(rqstp, fhp, may_flags, NULL, pnf, true);
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return nfsd_file_do_acquire(rqstp, SVC_NET(rqstp), NULL, NULL,
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fhp, may_flags, NULL, pnf, true);
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}
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/**
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@ -1167,7 +1175,55 @@ __be32
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nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
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unsigned int may_flags, struct nfsd_file **pnf)
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{
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return nfsd_file_do_acquire(rqstp, fhp, may_flags, NULL, pnf, false);
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return nfsd_file_do_acquire(rqstp, SVC_NET(rqstp), NULL, NULL,
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fhp, may_flags, NULL, pnf, false);
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}
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/**
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* nfsd_file_acquire_local - Get a struct nfsd_file with an open file for localio
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* @net: The network namespace in which to perform a lookup
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* @cred: the user credential with which to validate access
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* @client: the auth_domain for LOCALIO lookup
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* @fhp: the NFS filehandle of the file to be opened
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* @may_flags: NFSD_MAY_ settings for the file
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* @pnf: OUT: new or found "struct nfsd_file" object
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*
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* This file lookup interface provide access to a file given the
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* filehandle and credential. No connection-based authorisation
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* is performed and in that way it is quite different to other
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* file access mediated by nfsd. It allows a kernel module such as the NFS
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* client to reach across network and filesystem namespaces to access
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* a file. The security implications of this should be carefully
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* considered before use.
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*
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* The nfsd_file object returned by this API is reference-counted
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* and garbage-collected. The object is retained for a few
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* seconds after the final nfsd_file_put() in case the caller
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* wants to re-use it.
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*
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* Return values:
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* %nfs_ok - @pnf points to an nfsd_file with its reference
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* count boosted.
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*
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* On error, an nfsstat value in network byte order is returned.
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*/
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__be32
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nfsd_file_acquire_local(struct net *net, struct svc_cred *cred,
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struct auth_domain *client, struct svc_fh *fhp,
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unsigned int may_flags, struct nfsd_file **pnf)
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{
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/*
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* Save creds before calling nfsd_file_do_acquire() (which calls
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* nfsd_setuser). Important because caller (LOCALIO) is from
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* client context.
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*/
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const struct cred *save_cred = get_current_cred();
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__be32 beres;
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beres = nfsd_file_do_acquire(NULL, net, cred, client,
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fhp, may_flags, NULL, pnf, true);
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revert_creds(save_cred);
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return beres;
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}
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/**
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@ -1193,7 +1249,8 @@ nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp,
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unsigned int may_flags, struct file *file,
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struct nfsd_file **pnf)
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{
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return nfsd_file_do_acquire(rqstp, fhp, may_flags, file, pnf, false);
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return nfsd_file_do_acquire(rqstp, SVC_NET(rqstp), NULL, NULL,
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fhp, may_flags, file, pnf, false);
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}
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/*
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@ -66,5 +66,8 @@ __be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
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__be32 nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp,
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unsigned int may_flags, struct file *file,
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struct nfsd_file **nfp);
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__be32 nfsd_file_acquire_local(struct net *net, struct svc_cred *cred,
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struct auth_domain *client, struct svc_fh *fhp,
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unsigned int may_flags, struct nfsd_file **pnf);
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int nfsd_file_cache_stats_show(struct seq_file *m, void *v);
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#endif /* _FS_NFSD_FILECACHE_H */
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@ -392,6 +392,29 @@ out:
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return error;
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}
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/**
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* fh_verify_local - filehandle lookup and access checking
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* @net: net namespace in which to perform the export lookup
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* @cred: RPC user credential
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* @client: RPC auth domain
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* @fhp: filehandle to be verified
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* @type: expected type of object pointed to by filehandle
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* @access: type of access needed to object
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*
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* This API can be used by callers who do not have an RPC
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* transaction context (ie are not running in an nfsd thread).
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*
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* See fh_verify() for further descriptions of @fhp, @type, and @access.
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*/
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__be32
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fh_verify_local(struct net *net, struct svc_cred *cred,
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struct auth_domain *client, struct svc_fh *fhp,
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umode_t type, int access)
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{
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return __fh_verify(NULL, net, cred, client, NULL,
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fhp, type, access);
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}
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/**
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* fh_verify - filehandle lookup and access checking
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* @rqstp: pointer to current rpc request
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@ -217,6 +217,8 @@ extern char * SVCFH_fmt(struct svc_fh *fhp);
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* Function prototypes
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*/
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__be32 fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
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__be32 fh_verify_local(struct net *, struct svc_cred *, struct auth_domain *,
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struct svc_fh *, umode_t, int);
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__be32 fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
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__be32 fh_update(struct svc_fh *);
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void fh_put(struct svc_fh *);
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