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Message-ID: <baaef4711002182338g17e42a7dpa47242dd334a27c2@mail.gmail.com> Date: Fri, 19 Feb 2010 08:38:15 +0100 From: Camille Moncelier <pix@...life.org> To: linux-fsdevel@...r.kernel.org Cc: Andreas Dilger <adilger@....com>, ext4 development <linux-ext4@...r.kernel.org> Subject: Re: [ext3] Changes to block device after an ext3 mount point has been remounted readonly On Thu, Feb 18, 2010 at 10:41 PM, Andreas Dilger <adilger@....com> wrote: > Are you sure this isn't because e2fsck has been run at boot time and changed > e.g. the "last checked" timestamp in the superblock? > No, I replaced /sbin/init by something which compute the sha1sum of the root partition, display it then call /sbin/init and I can see that the hash has changed after mount -o remount,ro. As little as I understand, I managed to make a diff between two hexdump of small images where changes happened after I created a file and remounted the fs ro and it seems that, the driver didn't wrote changes to the disk until unmount ( The hexdump clearly shows that /lost+found and /test file has been written after the umount ) workaround: Is there some knob in /proc or /sys which can trigger all pending changes to disk ? ( Like /proc/sys/vm/drop_caches but for filesystems ? ) >> This only happen when the rootfs hash been mounted ro, then remounted >> rw to make some changes and remounted ro. >> On the next reboot the hash will change, but only one time. Next >> reboots will not alter the control sum, until of course I remount it >> RW. > > > Cheers, Andreas > -- > Andreas Dilger > Sr. Staff Engineer, Lustre Group > Sun Microsystems of Canada, Inc. > > -- Camille Moncelier http://devlife.org/ If Java had true garbage collection, most programs would delete themselves upon execution. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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