Date: Wed, 4 May 2011 05:47:52 +0800 From: Sergey Lobanov <wmn@siberianet.ru> To: freebsd-fs@freebsd.org Subject: fsck_ufs only in preen mode terminates with non-zero exit status trying to check absent device Message-ID: <201105040547.52216.wmn@siberianet.ru>
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Hello,
I am trying to workaround problem in setup with md(4) file-backed images
mounted in jails(8). I could not find how to automatically check file systems on
md images during system boot or jail start. That is, after hard system reset
(for example, because of power loss) file systems on md file-backed images are
all dirty and is not auto-repaired out of the box. May be I've missed
something, feel free to point me out to the documentation describing the case.
Here is workaround i am trying to make:
1) md images are all added into jail fstabs so system can boot normally
(because if images are in host fstab, system stops on check of such obviously
absent at boot time devices).
2) I use ezjail, so we add hack into its rc-NG script which executes external
script to check file systems on corresponding md images before jail start;
ezjail script relies on exit status of this external script, so we can skip
jail if check have been failed.
3) The script for check of md images gets jail name as parameter, greps
/dev/md* rows from corresponding fstab file and tries to fsck in preen mode
first and then in normal mode if first fails. And here we get problem with fsck:
in preen mode it exits with non-zero status if device is not present, but if
we then launch it in normal mode for the same device, it prints errors and
terminates with status 0.
Example script (test-fsck-ufs.sh):
--------------------
#!/bin/sh
rc_info="YES"
. /etc/rc.subr
/sbin/fsck_ufs -p /dev/md-non-existent
if [ $? -ne 0 ]; then
warn "Could not check in preen mode, trying normal..."
/sbin/fsck_ufs -y /dev/md-non-existent || err $? "Could not check in normal
mode, XXX IMAGE FILE IS CORRUPT XXX"
else
info "Consistent"
fi
--------------------
Result of execution of above script on 8.2-stable r220968 and 7.3-stable
r215651:
Can't stat /dev/md-non-existent: No such file or directory
./test-fsck-ufs.sh: WARNING: Could not check in preen mode, trying normal...
Can't stat /dev/md-non-existent: No such file or directory
Can't stat /dev/md-non-existent: No such file or directory
Which is incorrect from my point of view, fsck_ffs(8) clearly states at the
very end:
"EXIT STATUS
The fsck_ffs utility exits 0 on success, and >0 if an error occurs."
I can definitely hack fsck_ffs so it will return error on such conditions,
something like this (fixes my case but was not checked in normal operation,
patch for releng8):
---patch start---
--- sbin/fsck_ffs/main.c.orig 2011-05-04 04:11:18.000000000 +0800
+++ sbin/fsck_ffs/main.c 2011-05-04 04:29:23.000000000 +0800
@@ -70,6 +70,7 @@
static int checkfilesys(char *filesys);
static int chkdoreload(struct statfs *mntp);
static struct statfs *getmntpt(const char *);
+char fails = 0;
int
main(int argc, char *argv[])
@@ -179,6 +180,8 @@
if (returntosingle)
ret = 2;
+ else
+ if (fails) ret = EEXIT;
exit(ret);
}
@@ -373,6 +376,7 @@
case 0:
if (preen)
pfatal("CAN'T CHECK FILE SYSTEM.");
+ fails = 1;
return (0);
case -1:
clean:
---patch end---
but may be there is some other, more sane way.
Or I've just missed something, there is strong reason for such behaviour and
it is a feature actually :}
I am subscribed to the list so there is no need to add me to CC.
--
ISP SiberiaNet
System and Network Administrator
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