[PATCH v2 2/2] nfsd: store stat times in fill_pre_wcc() instead of inode times

[Amir Goldstein <amir73il@xxxxxxxxx>]

The time values in stat and inode may differ for overlayfs and stat time
values are the correct ones to use. This is also consistent with the fact
that fill_post_wcc() also stores stat time values.

Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
 fs/nfsd/nfs3xdr.c | 31 ++++++++++++++++++++++++++++++-
 fs/nfsd/nfs4xdr.c |  2 +-
 fs/nfsd/nfsfh.h   | 28 ++++++----------------------
 3 files changed, 37 insertions(+), 24 deletions(-)

diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index 2758480555fa..1a70581e1cb2 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -251,6 +251,34 @@ encode_wcc_data(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp)
 }
 
 /*
+ * Fill in the pre_op attr for the wcc data
+ */
+void fill_pre_wcc(struct svc_fh *fhp)
+{
+	struct inode    *inode;
+	struct kstat	stat;
+	__be32 err;
+
+	if (fhp->fh_pre_saved)
+		return;
+
+	inode = d_inode(fhp->fh_dentry);
+	err = fh_getattr(fhp, &stat);
+	if (err) {
+		/* Grab the times from inode anyway */
+		stat.mtime = inode->i_mtime;
+		stat.ctime = inode->i_ctime;
+		stat.size  = inode->i_size;
+	}
+
+	fhp->fh_pre_mtime = stat.mtime;
+	fhp->fh_pre_ctime = stat.ctime;
+	fhp->fh_pre_size  = stat.size;
+	fhp->fh_pre_change = nfsd4_change_attribute(&stat, inode);
+	fhp->fh_pre_saved = true;
+}
+
+/*
  * Fill in the post_op attr for the wcc data
  */
 void fill_post_wcc(struct svc_fh *fhp)
@@ -261,7 +289,8 @@ void fill_post_wcc(struct svc_fh *fhp)
 		printk("nfsd: inode locked twice during operation.\n");
 
 	err = fh_getattr(fhp, &fhp->fh_post_attr);
-	fhp->fh_post_change = nfsd4_change_attribute(d_inode(fhp->fh_dentry));
+	fhp->fh_post_change = nfsd4_change_attribute(&fhp->fh_post_attr,
+						     d_inode(fhp->fh_dentry));
 	if (err) {
 		fhp->fh_post_saved = false;
 		/* Grab the ctime anyway - set_change_info might use it */
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 2c61c6b8ae09..fbe11ad9b9ff 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1991,7 +1991,7 @@ static __be32 *encode_change(__be32 *p, struct kstat *stat, struct inode *inode,
 		*p++ = cpu_to_be32(convert_to_wallclock(exp->cd->flush_time));
 		*p++ = 0;
 	} else if (IS_I_VERSION(inode)) {
-		p = xdr_encode_hyper(p, nfsd4_change_attribute(inode));
+		p = xdr_encode_hyper(p, nfsd4_change_attribute(stat, inode));
 	} else {
 		*p++ = cpu_to_be32(stat->ctime.tv_sec);
 		*p++ = cpu_to_be32(stat->ctime.tv_nsec);
diff --git a/fs/nfsd/nfsfh.h b/fs/nfsd/nfsfh.h
index 43f31cf49bae..99be87b50ebe 100644
--- a/fs/nfsd/nfsfh.h
+++ b/fs/nfsd/nfsfh.h
@@ -252,36 +252,20 @@ fh_clear_wcc(struct svc_fh *fhp)
  * By using both ctime and the i_version counter we guarantee that as
  * long as time doesn't go backwards we never reuse an old value.
  */
-static inline u64 nfsd4_change_attribute(struct inode *inode)
+static inline u64 nfsd4_change_attribute(struct kstat *stat,
+					 struct inode *inode)
 {
 	u64 chattr;
 
-	chattr =  inode->i_ctime.tv_sec;
+	chattr =  stat->ctime.tv_sec;
 	chattr <<= 30;
-	chattr += inode->i_ctime.tv_nsec;
+	chattr += stat->ctime.tv_nsec;
 	chattr += inode->i_version;
 	return chattr;
 }
 
-/*
- * Fill in the pre_op attr for the wcc data
- */
-static inline void
-fill_pre_wcc(struct svc_fh *fhp)
-{
-	struct inode    *inode;
-
-	inode = d_inode(fhp->fh_dentry);
-	if (!fhp->fh_pre_saved) {
-		fhp->fh_pre_mtime = inode->i_mtime;
-		fhp->fh_pre_ctime = inode->i_ctime;
-		fhp->fh_pre_size  = inode->i_size;
-		fhp->fh_pre_change = nfsd4_change_attribute(inode);
-		fhp->fh_pre_saved = true;
-	}
-}
-
-extern void fill_post_wcc(struct svc_fh *);
+extern void fill_pre_wcc(struct svc_fh *fhp);
+extern void fill_post_wcc(struct svc_fh *fhp);
 #else
 #define fh_clear_wcc(ignored)
 #define fill_pre_wcc(ignored)
-- 
2.7.4