From mboxrd@z Thu Jan 1 00:00:00 1970 From: Claudio Martins Subject: Re: Mass-Hardlinking Oops Date: Tue, 13 Oct 2009 01:31:25 +0100 Message-ID: <200910130131.26380.ctpm@ist.utl.pt> References: <4A74401B.90801@mccme.ru> <4AD372A7.2020907@hp.com> <20091012200442.GA8830@think> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: jim owens , John Dong , =?utf-8?q?P=C3=A4r_Andersson?= , linux-btrfs@vger.kernel.org, "Yan, Zheng " , Tomasz Chmielewski To: Chris Mason Return-path: In-Reply-To: <20091012200442.GA8830@think> List-ID: On Monday 12 October 2009, Chris Mason wrote: > On Mon, Oct 12, 2009 at 02:17:11PM -0400, jim owens wrote: > > John Dong wrote: > > >I don't think that's a good counterargument for why this is not a = bug. > > > > it is not a "bug". hard links are not a required feature of all > > filesystems nor is a defined large number required for those with > > hard links. > > > > >Can't think of any off the top of my head for Linux, but > > >definitely in OS X Time Machine can easily create 200+ hardlinks. > > > > so 311 is 50% than the app uses... plenty of growth. > > Just to clarify again, the max link count on btrfs is 2^32. The lowe= r > limit is only in place on links to the same file in the same director= y. > Hi Chris and all, I've made a quick test and managed to create many more links to the sa= me file=20 in the *same* directory on other filsystems:=20 XFS can do at least 100000, probably more;=20 Reiserfs did 64535; ext3 managed to do 32000; ext4 did 65000. While I agree it might be a bit stupid to create so many hardlinks to = the=20 same file on the same directory, this issue can be seen as one of "back= ward=20 compatibility" with other widely used and established Linux filesystems= =2E=20 Despite it being stupid or not, the fact is that I've seen some crazy s= tuff=20 along the years working with Unix, so people will expect this kind of t= hings=20 to *not* break when they switch from their old filesystems to shiny new= =20 btrfs. The fact being that this limit is way lower than on other filesystems = (we're=20 talking 2 orders of magnitude, at best!), I too suggest that the limit = should=20 be increased. Not being critical, it might be done when some other feat= ures=20 require a format change but, nonetheless, should be done for the sake o= f=20 avoiding breakage on existing systems. Best regards, and thanks for your hard work. Cl=C3=A1udio -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" = in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html