[RFC PATCH 0/2] Relocate fh_getattr()

[RFC PATCH 0/2] Relocate fh_getattr()

[Chuck Lever]

From: Chuck Lever <chuck.lever@oracle.com>

Tucked away in Mike's LOCALIO branch is a patch that, among other
changes, moves fh_getattr() to fs/nfsd/vfs.c. My feeling is that
either:

 - fh_getattr() remains as part of the NFSD FH API, thus it belongs
   in fs/nfsd/nfsfh.c; or

 - if it is to be relocated to fs/nfsd/vfs.c, then it should adopt
   the naming convention used for the public functions in that
   source file.

This patch series tries on the first approach, for size.

It's a nit, I know.

Chuck Lever (2):
  NFSD: Relocate the fh_want_write() and fh_drop_write() helpers
  NFSD: Move the fh_getattr() helper

 fs/nfsd/nfsfh.c | 23 +++++++++++++++++++++++
 fs/nfsd/nfsfh.h | 38 ++++++++++++++++++++++++++++++++++++++
 fs/nfsd/vfs.h   | 33 ---------------------------------
 3 files changed, 61 insertions(+), 33 deletions(-)

-- 
2.50.0

[RFC PATCH 1/2] NFSD: Relocate the fh_want_write() and fh_drop_write() helpers

[Chuck Lever]

From: Chuck Lever <chuck.lever@oracle.com>

Clean up: These helpers are part of the NFSD file handle API.
Relocate them to fs/nfsd/nfsfh.h.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfsfh.h | 37 +++++++++++++++++++++++++++++++++++++
 fs/nfsd/vfs.h   | 20 --------------------
 2 files changed, 37 insertions(+), 20 deletions(-)

diff --git a/fs/nfsd/nfsfh.h b/fs/nfsd/nfsfh.h
index 1cf979722521..6f5255d1c190 100644
--- a/fs/nfsd/nfsfh.h
+++ b/fs/nfsd/nfsfh.h
@@ -14,6 +14,8 @@
 #include <linux/exportfs.h>
 #include <linux/nfs4.h>
 
+#include "export.h"
+
 /*
  * The file handle starts with a sequence of four-byte words.
  * The first word contains a version number (1) and three descriptor bytes
@@ -271,6 +273,41 @@ static inline bool fh_fsid_match(const struct knfsd_fh *fh1,
 	return true;
 }
 
+/**
+ * fh_want_write - Get write access to an export
+ * @fhp: File handle of file to be written
+ *
+ * Caller must invoke fh_drop_write() when its write operation
+ * is complete.
+ *
+ * Returns 0 if the file handle's export can be written to. Otherwise
+ * the export is not prepared for updates, and the returned negative
+ * errno value reflects the reason for the failure.
+ */
+static inline int fh_want_write(struct svc_fh *fhp)
+{
+	int ret;
+
+	if (fhp->fh_want_write)
+		return 0;
+	ret = mnt_want_write(fhp->fh_export->ex_path.mnt);
+	if (!ret)
+		fhp->fh_want_write = true;
+	return ret;
+}
+
+/**
+ * fh_drop_write - Release write access on an export
+ * @fhp: File handle of file on which fh_want_write() was previously called
+ */
+static inline void fh_drop_write(struct svc_fh *fhp)
+{
+	if (fhp->fh_want_write) {
+		fhp->fh_want_write = false;
+		mnt_drop_write(fhp->fh_export->ex_path.mnt);
+	}
+}
+
 /**
  * knfsd_fh_hash - calculate the crc32 hash for the filehandle
  * @fh - pointer to filehandle
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index eff04959606f..4007dcbbbfef 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -160,26 +160,6 @@ __be32		nfsd_permission(struct svc_cred *cred, struct svc_export *exp,
 
 void		nfsd_filp_close(struct file *fp);
 
-static inline int fh_want_write(struct svc_fh *fh)
-{
-	int ret;
-
-	if (fh->fh_want_write)
-		return 0;
-	ret = mnt_want_write(fh->fh_export->ex_path.mnt);
-	if (!ret)
-		fh->fh_want_write = true;
-	return ret;
-}
-
-static inline void fh_drop_write(struct svc_fh *fh)
-{
-	if (fh->fh_want_write) {
-		fh->fh_want_write = false;
-		mnt_drop_write(fh->fh_export->ex_path.mnt);
-	}
-}
-
 static inline __be32 fh_getattr(const struct svc_fh *fh, struct kstat *stat)
 {
 	u32 request_mask = STATX_BASIC_STATS;
-- 
2.50.0

[RFC PATCH 2/2] NFSD: Move the fh_getattr() helper

[Chuck Lever]

From: Chuck Lever <chuck.lever@oracle.com>

Clean up: The fh_getattr() function is part of NFSD's file handle
API, so relocate it.

I've made it an un-inlined function so that trace points and new
functionality can easily be introduced. That increases the size of
nfsd.ko by about a page on my x86_64 system (out of 26MB; compiled
with -O2).

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfsfh.c | 23 +++++++++++++++++++++++
 fs/nfsd/nfsfh.h |  1 +
 fs/nfsd/vfs.h   | 13 -------------
 3 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index 4565112d0324..6f59f957407f 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -662,6 +662,29 @@ fh_update(struct svc_fh *fhp)
 	return nfserr_serverfault;
 }
 
+/**
+ * fh_getattr - Retrieve attributes on a local file
+ * @fhp: File handle of target file
+ * @stat: Caller-supplied kstat buffer to be filled in
+ *
+ * Returns nfs_ok on success, otherwise an NFS status code is
+ * returned.
+ */
+__be32 fh_getattr(const struct svc_fh *fhp, struct kstat *stat)
+{
+	struct path p = {
+		.mnt		= fhp->fh_export->ex_path.mnt,
+		.dentry		= fhp->fh_dentry,
+	};
+	u32 request_mask = STATX_BASIC_STATS;
+
+	if (fhp->fh_maxsize == NFS4_FHSIZE)
+		request_mask |= (STATX_BTIME | STATX_CHANGE_COOKIE);
+
+	return nfserrno(vfs_getattr(&p, stat, request_mask,
+				    AT_STATX_SYNC_AS_STAT));
+}
+
 /**
  * fh_fill_pre_attrs - Fill in pre-op attributes
  * @fhp: file handle to be updated
diff --git a/fs/nfsd/nfsfh.h b/fs/nfsd/nfsfh.h
index 6f5255d1c190..5ef7191f8ad8 100644
--- a/fs/nfsd/nfsfh.h
+++ b/fs/nfsd/nfsfh.h
@@ -222,6 +222,7 @@ extern char * SVCFH_fmt(struct svc_fh *fhp);
 __be32	fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
 __be32	fh_verify_local(struct net *, struct svc_cred *, struct auth_domain *,
 			struct svc_fh *, umode_t, int);
+__be32	fh_getattr(const struct svc_fh *fhp, struct kstat *stat);
 __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 *);
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index 4007dcbbbfef..0c0292611c6d 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -160,17 +160,4 @@ __be32		nfsd_permission(struct svc_cred *cred, struct svc_export *exp,
 
 void		nfsd_filp_close(struct file *fp);
 
-static inline __be32 fh_getattr(const struct svc_fh *fh, struct kstat *stat)
-{
-	u32 request_mask = STATX_BASIC_STATS;
-	struct path p = {.mnt = fh->fh_export->ex_path.mnt,
-			 .dentry = fh->fh_dentry};
-
-	if (fh->fh_maxsize == NFS4_FHSIZE)
-		request_mask |= (STATX_BTIME | STATX_CHANGE_COOKIE);
-
-	return nfserrno(vfs_getattr(&p, stat, request_mask,
-				    AT_STATX_SYNC_AS_STAT));
-}
-
 #endif /* LINUX_NFSD_VFS_H */
-- 
2.50.0