To: Kirk McKusick <[EMAIL PROTECTED]>
cc: "[iso-8859-2] Branko F. Gračnar" <[EMAIL PROTECTED]>,
Paul Saab <[EMAIL PROTECTED]>,
Robert Watson <[EMAIL PROTECTED]>,
[EMAIL PROTECTED]
Subject: Re: mksnap_ffs, snapshot issues, again
From: "Poul-Henning Kamp" <[EMAIL PROTECTED]>
In-Reply-To: Your message of "Sat, 23 Aug 2003 01:32:38 PDT."
Date: Sat, 23 Aug 2003 11:01:28 +0200
X-ASK-Info: Whitelist match
In message <[EMAIL PROTECTED]>,
Kirk McKusick writes:
>But, to get to the problem that you are having with accessing your
>filesystem. The problem is that although the filesystem is only
>locked briefly, the snapshot file is locked for the entire 48 minutes.
>Thus, if you touch the snapshot file (by for example doing a "stat"
>on it), then the process doing the stat will hang for 48 minutes.
Isn't there some way we can loosen this aspect up ?
Either by having stat know about it and return approximate info or
simply by failing ? (I pressume that making the sleep interruptible
would break all sorts of standards)
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED] | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
The race to the root problem in general could be largely solved
by changing lookup (VOP_LOOKUP really) to release the lock that
it holds on the directory before blocking on the next component
in the case where it is doing a lookup without intent to create.
If we did this, then a single locked node would have lookups
pile up on itself, but could not cascade to the root. A related
change would be to do an interruptable locking request on the
node so that if one did an `ls -l foo' where foo was say a
locked snapshot, it would be possible to interrupt it.
~Kirk
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