From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: [PATCH] dumpe2fs: Warn when filesystem is mounted read-write Date: Thu, 28 Jul 2011 17:17:04 +0200 Message-ID: <1311866224-27351-1-git-send-email-jack@suse.cz> Cc: linux-ext4@vger.kernel.org, Jan Kara To: Ted Tso Return-path: Received: from cantor2.suse.de ([195.135.220.15]:43423 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754623Ab1G1PRI (ORCPT ); Thu, 28 Jul 2011 11:17:08 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: When dumpe2fs is used on a filesystem mounted read-write, printed information may be old and inconsistent because e.g. updates of some superblock fields happen lazily or because we do not really try to handle various intermediate states of filesystem operations. Document this in the manpage and warn user when dumpe2fs is used for such filesystem. Signed-off-by: Jan Kara --- misc/dumpe2fs.8.in | 3 ++- misc/dumpe2fs.c | 14 ++++++++++++++ 2 files changed, 16 insertions(+), 1 deletions(-) Ted, would you take this change? We actually had to explain to our users that what they were doing isn't really going to work reliably... diff --git a/misc/dumpe2fs.8.in b/misc/dumpe2fs.8.in index c1dfcbd..e1336dc 100644 --- a/misc/dumpe2fs.8.in +++ b/misc/dumpe2fs.8.in @@ -71,7 +71,8 @@ print the version number of and exit. .SH BUGS You need to know the physical filesystem structure to understand the -output. +output. When used with a mounted filesystem, the printed information may be +old or inconsistent. .SH AUTHOR .B dumpe2fs was written by Remy Card . It is currently being diff --git a/misc/dumpe2fs.c b/misc/dumpe2fs.c index 9a0dd46..fa1362a 100644 --- a/misc/dumpe2fs.c +++ b/misc/dumpe2fs.c @@ -495,6 +495,7 @@ int main (int argc, char ** argv) int flags; int header_only = 0; int c; + int mount_flags; #ifdef ENABLE_NLS setlocale(LC_MESSAGES, ""); @@ -567,6 +568,13 @@ int main (int argc, char ** argv) printf (_("Couldn't find valid filesystem superblock.\n")); exit (1); } + retval = ext2fs_check_if_mounted(device_name, &mount_flags); + if (retval) { + com_err("ext2fs_check_if_mount", retval, + _("while determining whether %s is mounted."), + device_name); + exit(1); + } if (print_badblocks) { list_bad_blocks(fs, 1); } else { @@ -595,6 +603,12 @@ int main (int argc, char ** argv) } } ext2fs_close (fs); + if ((mount_flags & EXT2_MF_MOUNTED) && + !(mount_flags & EXT2_MF_READONLY)) { + fputs(_("The filesystem is read-write mounted so printed" + " information may be old or inconsistent.\n"), stderr); + } + remove_error_table(&et_ext2_error_table); exit (0); } -- 1.7.1