nfsd: only call inode_query_iversion in the I_VERSION case
inode_query_iversion() can modify i_version. Depending on the exported
filesystem, that may not be safe. For example, if you're re-exporting
NFS, NFS stores the server's change attribute in i_version and does not
expect it to be modified locally. This has been observed causing
unnecessary cache invalidations.
The way a filesystem indicates that it's OK to call
inode_query_iverson() is by setting SB_I_VERSION.
So, move the I_VERSION check out of encode_change(), where it's used
only in GETATTR responses, to nfsd4_change_attribute(), which is
also called for pre- and post- operation attributes.
(Note we could also pull the NFSEXP_V4ROOT case into
nfsd4_change_attribute() as well. That would actually be a no-op,
since pre/post attrs are only used for metadata-modifying operations,
and V4ROOT exports are read-only. But we might make the change in
the future just for simplicity.)
Reported-by: Daire Byrne <daire@dneg.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 7142b05..ef1f553 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2426,12 +2426,8 @@ static __be32 *encode_change(__be32 *p, struct kstat *stat, struct inode *inode,
if (exp->ex_flags & NFSEXP_V4ROOT) {
*p++ = cpu_to_be32(convert_to_wallclock(exp->cd->flush_time));
*p++ = 0;
- } else if (IS_I_VERSION(inode)) {
+ } else
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);
- }
return p;
}