Date: Wed, 02 Jan 2013 23:07:24 +0100 From: Andreas Longwitz <longwitz@incore.de> To: freebsd-fs@freebsd.org Subject: g_journal_ufs_using_last_sector() needs minor correction (patch included) Message-ID: <50E4AF9C.9060404@incore.de>
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On a testdisk created with
dd if=/dev/zero of=diskfile count=5000 bs=1m
mdconfig -a -t vnode -f diskfile -u 1
let us create a mirrored and gjournaled filesystem:
gmirror label -b prefer -F gmX md1
gpart create -s GPT mirror/gmX
gpart add -t freebsd-swap -s 4194304 -i 1 mirror/gmX
gpart add -t freebsd-ufs -i 2 mirror/gmX
gjournal label mirror/gmXp2 mirror/gmXp1
newfs -J /dev/mirror/gmXp2.journal
mount /dev/mirror/gmXp2.journal /mnt
... put some data to /mnt
umount /mnt
The mediasizes in sectors for gjournal consumer and provider:
diskinfo /dev/mirror/gmXp2.journal -->
/dev/mirror/gmXp2.journal 512 3095361024 6045627 0 0
dumpfs -m /dev/mirror/gmXp2.journal -->
# newfs command for /dev/mirror/gmXp2.journal
newfs -O 2 -J -a 8 -b 16384 -d 16384 -e 2048 -f 2048 -g 16384 -h 64
-m 8 -o time -s 6045624 /dev/mirror/gmXp2.journal
The size of the created filesystem is 6045624 and three blocks less than
the size gjournal provides.
Now I had the need to rename gmX to gmY without loosing my data:
gjournal stop mirror/gmXp2.journal
gjournal clear mirror/gmXp2
gjournal clear mirror/gmXp1
gpart delete -i 1 mirror/gmX
gpart delete -i 2 mirror/gmX
gpart destroy mirror/gmX
gmirror stop gmX
gmirror clear /dev/md1
gmirror label -b prefer -F gmY md1
gpart create -s GPT mirror/gmY
gpart add -t freebsd-swap -s 4194304 -i 1 mirror/gmY
gpart add -t freebsd-ufs -i 2 mirror/gmY
gjournal label mirror/gmYp2 mirror/gmYp1
At this point gjournal gives the unjustified error message
"File system on mirror/gmYp2 is using the last
sector and this operation is going to overwrite
it. Use -f if you really want to do it."
the reason for this is an improper size check in the function
g_journal_ufs_using_last_sector() which can be corrected by the
following patch:
--- geom_journal_ufs.c.orig 2009-08-03 10:13:06.000000000 +0200
+++ geom_journal_ufs.c 2013-01-02 23:01:37.000000000 +0100
@@ -73,6 +73,6 @@
/* Provider size in 512 bytes blocks. */
psize = g_get_mediasize(prov) / DEV_BSIZE;
/* File system size in 512 bytes blocks. */
- fssize = fsbtodb(fs, dbtofsb(fs, psize));
- return (psize == fssize);
+ fssize = fsbtodb(fs, fs->fs_size);
+ return (psize <= fssize);
}
--
Andreas Longwitz
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