ceph: ignore the truncate when size won't change with Fx caps issued

If the new size is the same as the current size, the MDS will do nothing
but change the mtime/atime. POSIX doesn't mandate that the filesystems
must update them in this case, so just ignore it instead.

Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index c22c0676090f9eae74e1794bb2c670cb56eda76b..e3322fcb2e8d92df6439a946eec3edb62949327e 100644 (file)
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -2103,12 +2103,14 @@ int __ceph_setattr(struct inode *inode, struct iattr *attr)
                loff_t isize = i_size_read(inode);
 
                dout("setattr %p size %lld -> %lld\n", inode, isize, attr->ia_size);
-               if ((issued & CEPH_CAP_FILE_EXCL) && attr->ia_size > isize) {
-                       i_size_write(inode, attr->ia_size);
-                       inode->i_blocks = calc_inode_blocks(attr->ia_size);
-                       ci->i_reported_size = attr->ia_size;
-                       dirtied |= CEPH_CAP_FILE_EXCL;
-                       ia_valid |= ATTR_MTIME;
+               if ((issued & CEPH_CAP_FILE_EXCL) && attr->ia_size >= isize) {
+                       if (attr->ia_size > isize) {
+                               i_size_write(inode, attr->ia_size);
+                               inode->i_blocks = calc_inode_blocks(attr->ia_size);
+                               ci->i_reported_size = attr->ia_size;
+                               dirtied |= CEPH_CAP_FILE_EXCL;
+                               ia_valid |= ATTR_MTIME;
+                       }
                } else if ((issued & CEPH_CAP_FILE_SHARED) == 0 ||
                           attr->ia_size != isize) {
                        req->r_args.setattr.size = cpu_to_le64(attr->ia_size);