unix: Don't drop whole socket with unlinked path

When we can't stat socket name with ENOENT errno this
means, that the socket is bound and unlinked. Don't
drop the whole socket info, just treat it as nameless.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

sk-unix.c

@@ -402,6 +402,7 @@ static int unix_collect_one(const struct unix_diag_msg *m,
 			struct unix_diag_vfs *uv;
 			struct stat st;
 			char rpath[PATH_MAX];
+			bool drop_path = false;
 
 			if (name[0] != '/') {
 				pr_warn("Relative bind path '%s' "
@@ -418,12 +419,16 @@ static int unix_collect_one(const struct unix_diag_msg *m,
 			uv = RTA_DATA(tb[UNIX_DIAG_VFS]);
 			snprintf(rpath, sizeof(rpath), ".%s", name);
 			if (fstatat(mntns_root, rpath, &st, 0)) {
+				if (errno != ENOENT) {
 					pr_warn("Can't stat socket %#x(%s), skipping: %m (err %d)\n",
 							m->udiag_ino, rpath, errno);
 					goto skip;
 				}
 
-			if ((st.st_ino != uv->udiag_vfs_ino) ||
+				pr_info("unix: Dropping path %s for unlinked sk %#x\n",
+						name, m->udiag_ino);
+				drop_path = true;
+			} else if ((st.st_ino != uv->udiag_vfs_ino) ||
 			    !phys_stat_dev_match(st.st_dev, uv->udiag_vfs_dev, name)) {
 				pr_info("unix: Dropping path %s for "
 						"unlinked bound "
@@ -433,6 +438,10 @@ static int unix_collect_one(const struct unix_diag_msg *m,
 						(int)st.st_ino,
 						(int)uv->udiag_vfs_dev,
 						(int)uv->udiag_vfs_ino);
+				drop_path = true;
+			}
+
+			if (drop_path) {
 				/*
 				 * When a socket is bound to unlinked file, we
 				 * just drop his name, since no one will access