nfsd: move nfsd4_change_attribute to nfsfh.c

This is a pretty big function for inlining. Move it to being
non-inlined.

Acked-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jeff Layton <jlayton@kernel.org>

1 files changed, 27 insertions, 0 deletions

diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index 8c52b6c9d31a..ac89e25e7733 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -748,3 +748,30 @@ enum fsid_source fsid_source(const struct svc_fh *fhp)
 		return FSIDSOURCE_UUID;
 	return FSIDSOURCE_DEV;
 }
+
+/*
+ * We could use i_version alone as the change attribute.  However,
+ * i_version can go backwards after a reboot.  On its own that doesn't
+ * necessarily cause a problem, but if i_version goes backwards and then
+ * is incremented again it could reuse a value that was previously used
+ * before boot, and a client who queried the two values might
+ * incorrectly assume nothing changed.
+ *
+ * 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.
+ */
+u64 nfsd4_change_attribute(struct kstat *stat, struct inode *inode)
+{
+	if (inode->i_sb->s_export_op->fetch_iversion)
+		return inode->i_sb->s_export_op->fetch_iversion(inode);
+	else if (IS_I_VERSION(inode)) {
+		u64 chattr;
+
+		chattr =  stat->ctime.tv_sec;
+		chattr <<= 30;
+		chattr += stat->ctime.tv_nsec;
+		chattr += inode_query_iversion(inode);
+		return chattr;
+	} else
+		return time_to_chattr(&stat->ctime);
+}