From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Kleikamp Subject: Re: [Jfs-discussion] [PATCH] fs/jfs: TRIM support for JFS Filesystem Date: Wed, 01 Aug 2012 15:07:31 -0500 Message-ID: <50198C83.4000500@oracle.com> References: <20120726213219.GA28330@mcmilk.de> <20120728110805.GA690@mcmilk.de> <50185916.7010705@oracle.com> <20120801192934.GB19139@mcmilk.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: jfs-discussion@lists.sourceforge.net, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org To: Tino Reichardt Return-path: In-Reply-To: <20120801192934.GB19139@mcmilk.de> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On 08/01/2012 02:29 PM, Tino Reichardt wrote: > * Dave Kleikamp wrote: >> On 07/28/2012 06:08 AM, Tino Reichardt wrote: >>> + tt->nblocks = 0; /* mark the current end */ >>> + for (tt = totrim; tt->nblocks != 0; tt++) { >>> + if (!(JFS_SBI(sb)->flag & JFS_DISCARD)) { >>> + /* not needed, when online discard is used */ >> >> Why enter the function at all if JFS_DISCARD is set? But is this really >> true? Removing files or file fragments that are smaller than >> minblks_trim will fail to discard them dynamically. > > The other FS can also trim via fstrim(8) when mounted with discard > option :) It is important, that a user can discard all free blocks, even > when mounting with discard option. The FS could also be mounted several > times without discard option, and then there are some ranges, where the > device isn't informed about these ranges. So the batched discard ioctl() > is then the only way to change that. > > > The comment there was also a bit updated, here is it: > > /* when mounted with online discard, dbFree() will > * call jfs_issue_discard() itself */ Ah. This comments makes it clear. I was forgetting that dbFree will handle this. Thanks, Dave