cifs: handle -EINTR in cifs_setattr

RHBZ: 1848178

Some calls that set attributes, like utimensat(), are not supposed to return
-EINTR and thus do not have handlers for this in glibc which causes us
to leak -EINTR to the applications which are also unprepared to handle it.

For example tar will break if utimensat() return -EINTR and abort unpacking
the archive. Other applications may break too.

To handle this we add checks, and retry, for -EINTR in cifs_setattr()

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/inode.c

@@ -2883,13 +2883,18 @@ cifs_setattr(struct dentry *direntry, struct iattr *attrs)
 {
 	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
 	struct cifs_tcon *pTcon = cifs_sb_master_tcon(cifs_sb);
+	int rc, retries = 0;
 
-	if (pTcon->unix_ext)
-		return cifs_setattr_unix(direntry, attrs);
-
-	return cifs_setattr_nounix(direntry, attrs);
+	do {
+		if (pTcon->unix_ext)
+			rc = cifs_setattr_unix(direntry, attrs);
+		else
+			rc = cifs_setattr_nounix(direntry, attrs);
+		retries++;
+	} while (is_retryable_error(rc) && retries < 2);
 
 	/* BB: add cifs_setattr_legacy for really old servers */
+	return rc;
 }
 
 #if 0