From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f50.google.com ([209.85.192.50]:36249 "EHLO mail-qg0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754920AbcCUMXR (ORCPT ); Mon, 21 Mar 2016 08:23:17 -0400 Received: by mail-qg0-f50.google.com with SMTP id u110so150197977qge.3 for ; Mon, 21 Mar 2016 05:23:17 -0700 (PDT) From: "Austin S. Hemmelgarn" To: linux-btrfs@vger.kernel.org, dsterba@suse.com Cc: "Austin S. Hemmelgarn" Subject: [PATCH] btrfs-progs: fix fi du so it works in more cases Date: Mon, 21 Mar 2016 08:23:11 -0400 Message-Id: <1458562991-6882-1-git-send-email-ahferroin7@gmail.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: Currently, btrfs fi du uses open_file_or_dir(), which tries to open it's argument with o_RDWR. Because of POSIX semantics, this fails for non-root users when the file is read-only or is an executable that is being run currently, or for all users (including root) when the filesystem is read-only. THis results in a somewhat confusing 'Unknown error -1' message when trying to check such files. Switch to using open_file_or_dir3() with O_RDONLY passed in the flags, as this avoids the limitations listed above, and we have no need to write to the files anyway (and thus shouldn't be opening them writable). Signed-off-by: Austin S. Hemmelgarn --- Build and runtime tested on x86-64 with glibc. I intend to take the time at some point this week to audit all users of open_file_or_dir() and similarly change any that don't need to write to what they're opening, possibly adding a helper function to do a read-only open. cmds-fi-du.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/cmds-fi-du.c b/cmds-fi-du.c index 2ffd917..168fc72 100644 --- a/cmds-fi-du.c +++ b/cmds-fi-du.c @@ -438,7 +438,7 @@ static int du_add_file(const char *filename, int dirfd, ret = sprintf(pathp, "/%s", filename); pathp += ret; - fd = open_file_or_dir(path, &dirstream); + fd = open_file_or_dir3(path, &dirstream, O_RDONLY); if (fd < 0) { ret = fd; goto out; -- 2.7.4