[PATCH v6 4/9] nfs: report the inode version in getattr if requested

[Jeff Layton <jlayton@kernel.org>]

Allow NFS to report the i_version in getattr requests. Since the cost to
fetch it is relatively cheap, do it unconditionally and just set the
flag if it looks like it's valid. Also, conditionally enable the
MONOTONIC flag when the server reports its change attr type as such.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/nfs/inode.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index bea7c005119c..5cb7017e5089 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -830,6 +830,8 @@ static u32 nfs_get_valid_attrmask(struct inode *inode)
 		reply_mask |= STATX_UID | STATX_GID;
 	if (!(cache_validity & NFS_INO_INVALID_BLOCKS))
 		reply_mask |= STATX_BLOCKS;
+	if (!(cache_validity & NFS_INO_INVALID_CHANGE))
+		reply_mask |= STATX_VERSION;
 	return reply_mask;
 }
 
@@ -848,7 +850,7 @@ int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
 
 	request_mask &= STATX_TYPE | STATX_MODE | STATX_NLINK | STATX_UID |
 			STATX_GID | STATX_ATIME | STATX_MTIME | STATX_CTIME |
-			STATX_INO | STATX_SIZE | STATX_BLOCKS;
+			STATX_INO | STATX_SIZE | STATX_BLOCKS | STATX_VERSION;
 
 	if ((query_flags & AT_STATX_DONT_SYNC) && !force_sync) {
 		if (readdirplus_enabled)
@@ -877,7 +879,7 @@ int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
 	/* Is the user requesting attributes that might need revalidation? */
 	if (!(request_mask & (STATX_MODE|STATX_NLINK|STATX_ATIME|STATX_CTIME|
 					STATX_MTIME|STATX_UID|STATX_GID|
-					STATX_SIZE|STATX_BLOCKS)))
+					STATX_SIZE|STATX_BLOCKS|STATX_VERSION)))
 		goto out_no_revalidate;
 
 	/* Check whether the cached attributes are stale */
@@ -915,6 +917,10 @@ int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
 
 	generic_fillattr(&init_user_ns, inode, stat);
 	stat->ino = nfs_compat_user_ino64(NFS_FILEID(inode));
+	stat->version = inode_peek_iversion_raw(inode);
+	stat->attributes_mask |= STATX_ATTR_VERSION_MONOTONIC;
+	if (server->change_attr_type != NFS4_CHANGE_TYPE_IS_UNDEFINED)
+		stat->attributes |= STATX_ATTR_VERSION_MONOTONIC;
 	if (S_ISDIR(inode->i_mode))
 		stat->blksize = NFS_SERVER(inode)->dtsize;
 out:
-- 
2.37.3