From: NeilBrown <neilb@xxxxxxx>
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. nfs_vers is 0, gssclient isn't passed).
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@xxxxxxxxxx> # use filecache's GC
Signed-off-by: NeilBrown <neilb@xxxxxxx>
Co-developed-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
fs/nfsd/filecache.c | 63 ++++++++++++++++++++++++++++++++++++++++-----
fs/nfsd/filecache.h | 4 +++
fs/nfsd/nfsfh.c | 2 +-
fs/nfsd/nfsfh.h | 5 ++++
4 files changed, 66 insertions(+), 8 deletions(-)
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 9e9d246f993c..94ecb9ed0ed1 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -982,12 +982,14 @@ nfsd_file_is_cached(struct inode *inode)
}
static __be32
-nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
+nfsd_file_do_acquire(struct svc_rqst *rqstp, struct net *net,
+ struct svc_cred *cred, int nfs_vers,
+ struct auth_domain *client,
+ struct svc_fh *fhp,
unsigned int may_flags, struct file *file,
struct nfsd_file **pnf, bool want_gc)
{
unsigned char need = may_flags & NFSD_FILE_MAY_MASK;
- struct net *net = SVC_NET(rqstp);
struct nfsd_file *new, *nf;
bool stale_retry = true;
bool open_retry = true;
@@ -996,8 +998,13 @@ nfsd_file_do_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
int ret;
retry:
- status = fh_verify(rqstp, fhp, S_IFREG,
- may_flags|NFSD_MAY_OWNER_OVERRIDE);
+ if (rqstp) {
+ status = fh_verify(rqstp, fhp, S_IFREG,
+ may_flags|NFSD_MAY_OWNER_OVERRIDE);
+ } else {
+ status = __fh_verify(NULL, net, cred, nfs_vers, client, NULL, fhp,
+ S_IFREG, may_flags|NFSD_MAY_OWNER_OVERRIDE);
+ }
if (status != nfs_ok)
return status;
inode = d_inode(fhp->fh_dentry);
@@ -1143,7 +1150,8 @@ __be32
nfsd_file_acquire_gc(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **pnf)
{
- return nfsd_file_do_acquire(rqstp, fhp, may_flags, NULL, pnf, true);
+ return nfsd_file_do_acquire(rqstp, SVC_NET(rqstp), NULL, 0, NULL,
+ fhp, may_flags, NULL, pnf, true);
}
/**
@@ -1167,7 +1175,47 @@ __be32
nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct nfsd_file **pnf)
{
- return nfsd_file_do_acquire(rqstp, fhp, may_flags, NULL, pnf, false);
+ return nfsd_file_do_acquire(rqstp, SVC_NET(rqstp), NULL, 0, NULL,
+ fhp, may_flags, NULL, pnf, false);
+}
+
+/**
+ * nfsd_file_acquire_local - Get a struct nfsd_file with an open file for localio
+ * @net: The network namespace in which to perform a lookup
+ * @cred: the user credential with which to validate access
+ * @nfs_vers: NFS version number to assume for request
+ * @client: the auth_domain for LOCALIO lookup
+ * @fhp: the NFS filehandle of the file to be opened
+ * @may_flags: NFSD_MAY_ settings for the file
+ * @pnf: OUT: new or found "struct nfsd_file" object
+ *
+ * This file lookup interface provide access to a file given the
+ * filehandle and credential. No connection-based authorisation
+ * is performed and in that way it is quite different to other
+ * file access mediated by nfsd. It allows a kernel module such as the NFS
+ * client to reach across network and filesystem namespaces to access
+ * a file. The security implications of this should be carefully
+ * considered before use.
+ *
+ * The nfsd_file object returned by this API is reference-counted
+ * and garbage-collected. The object is retained for a few
+ * seconds after the final nfsd_file_put() in case the caller
+ * wants to re-use it.
+ *
+ * Return values:
+ * %nfs_ok - @pnf points to an nfsd_file with its reference
+ * count boosted.
+ *
+ * On error, an nfsstat value in network byte order is returned.
+ */
+__be32
+nfsd_file_acquire_local(struct net *net, struct svc_cred *cred,
+ int nfs_vers, struct auth_domain *client,
+ struct svc_fh *fhp,
+ unsigned int may_flags, struct nfsd_file **pnf)
+{
+ return nfsd_file_do_acquire(NULL, net, cred, nfs_vers, client,
+ fhp, may_flags, NULL, pnf, true);
}
/**
@@ -1193,7 +1241,8 @@ nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct file *file,
struct nfsd_file **pnf)
{
- return nfsd_file_do_acquire(rqstp, fhp, may_flags, file, pnf, false);
+ return nfsd_file_do_acquire(rqstp, SVC_NET(rqstp), NULL, 0, NULL,
+ fhp, may_flags, file, pnf, false);
}
/*
diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h
index 3fbec24eea6c..6dab41f8541e 100644
--- a/fs/nfsd/filecache.h
+++ b/fs/nfsd/filecache.h
@@ -66,5 +66,9 @@ __be32 nfsd_file_acquire(struct svc_rqst *rqstp, struct svc_fh *fhp,
__be32 nfsd_file_acquire_opened(struct svc_rqst *rqstp, struct svc_fh *fhp,
unsigned int may_flags, struct file *file,
struct nfsd_file **nfp);
+__be32 nfsd_file_acquire_local(struct net *net, struct svc_cred *cred,
+ int nfs_vers, struct auth_domain *client,
+ struct svc_fh *fhp,
+ unsigned int may_flags, struct nfsd_file **pnf);
int nfsd_file_cache_stats_show(struct seq_file *m, void *v);
#endif /* _FS_NFSD_FILECACHE_H */
diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index 19e173187ab9..3635c0390cab 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -300,7 +300,7 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct net *net,
return error;
}
-static __be32
+__be32
__fh_verify(struct svc_rqst *rqstp,
struct net *net, struct svc_cred *cred,
int nfs_vers, struct auth_domain *client,
diff --git a/fs/nfsd/nfsfh.h b/fs/nfsd/nfsfh.h
index 8d46e203d139..1429bee0ac1c 100644
--- a/fs/nfsd/nfsfh.h
+++ b/fs/nfsd/nfsfh.h
@@ -217,6 +217,11 @@ extern char * SVCFH_fmt(struct svc_fh *fhp);
* Function prototypes
*/
__be32 fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
+__be32 __fh_verify(struct svc_rqst *rqstp,
+ struct net *net, struct svc_cred *cred,
+ int nfs_vers, struct auth_domain *client,
+ struct auth_domain *gssclient,
+ struct svc_fh *fhp, umode_t type, int access);
__be32 fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
__be32 fh_update(struct svc_fh *);
void fh_put(struct svc_fh *);
--
2.44.0
