From mboxrd@z Thu Jan  1 00:00:00 1970
From: bugzilla-daemon@bugzilla.kernel.org
Subject: [Bug 15906] serious performance regression in "umount" on ext4 over
 LVM
Date: Tue, 4 May 2010 21:11:04 GMT
Message-ID: <201005042111.o44LB43B017406@demeter.kernel.org>
References: <bug-15906-13602@https.bugzilla.kernel.org/>
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https://bugzilla.kernel.org/show_bug.cgi?id=15906





--- Comment #5 from Kees Cook <kees@outflux.net>  2010-05-04 21:11:03 ---
Hm, this was really a reduced test-case, as my initial situations where I
noticed this was umounting LVM snapshots, then later umounting aufs unions (in
an effort to get away from 3x slow-down of snapshot IO).

Doing this is just as slow as loopback for me:

VG=systemvg
lvcreate -n testlv -L1G $VG
mkfs.ext4 -F /dev/$VG/testlv
mkdir -p /mnt/test
mount -o loop /dev/$VG/testlv /mnt/test
seq 65536 | (cd /mnt/test; xargs touch)
time umount /mnt/test


Should 68db1961bbf4e16c220ccec4a780e966bc1fece3 be expected to fix it too?

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