From: Andreas Dilger Subject: Re: [RFC][PATCH 1/7]ext4: Add EXT4_IOC_ADD_GLOBAL_ALLOC_RULE restricts block allocation Date: Wed, 24 Jun 2009 02:11:58 +0200 Message-ID: <20090624001158.GQ31668@webber.adilger.int> References: <4A409168.3020404@rs.jp.nec.com> <20090623231950.GN31668@webber.adilger.int> <87f94c370906231702m6dde1402o9d2738f97f4b7df9@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Akira Fujita , linux-ext4@vger.kernel.org, "Theodore Ts'o" , linux-fsdevel@vger.kernel.org To: Greg Freemyer Return-path: Content-disposition: inline In-reply-to: <87f94c370906231702m6dde1402o9d2738f97f4b7df9@mail.gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Jun 23, 2009 20:02 -0400, Greg Freemyer wrote: > On Tue, Jun 23, 2009 at 7:19 PM, Andreas Dilger wrot= e: > > On Jun 23, 2009 =A017:25 +0900, Akira Fujita wrote: > >> alloc_flag of ext4_alloc_rule structure is set as "mandatory" or "= advisory". > >> Restricted blocks with "mandatory" are never used by block allocat= or. > >> But in "advisory" case, block allocator is allowed to use restrict= ed blocks > >> when there are no free blocks on FS. > > > > Would it make more sense to implement the range protections via the > > existing preallocation ranges (PA)? =A0An inode can have multiple > > PAs attached to it to have it prefer allocations from that range. > > > > We could also attach PAs to the superblock to prevent other files f= rom > > allocating out of those ranges. =A0This would work better with the = existing > > allocation code instead of creating a second similar mechanism. >=20 > Where can I find documentation about how PA works? Or is it just in > the source? If so, what are one or two calls that cause the PA range= s > to be set, etc. Aneesh is the expert on the preallocation code. Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html