From: Eric Sandeen Subject: Re: [PATCH V2] mke2fs: add discard to default mke2fs.conf and disable by default Date: Thu, 18 Apr 2013 19:09:31 -0400 (EDT) Message-ID: <6E0552E9-CEDA-4209-BFC3-D517D821D69B@redhat.com> References: <516F1C8A.9040702@redhat.com> <516F2DF7.2020005@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT Cc: ext4 development To: Eric Sandeen Return-path: Received: from mx3-phx2.redhat.com ([209.132.183.24]:59131 "EHLO mx3-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966999Ab3DRXJd convert rfc822-to-8bit (ORCPT ); Thu, 18 Apr 2013 19:09:33 -0400 In-Reply-To: <516F2DF7.2020005@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Apr 17, 2013, at 4:19 PM, Eric Sandeen wrote: > Discard is a very big hammer. If it succeeds, there's no undo > or going back; on the other hand, on some devices the giant discard > issued at mkfs time makes them go offline. > > Although I'm reluctant to waffle back and forth on default behavior, > I think this disabling it by default the prudent thing to do. > Ok, self-nak on this one, the folks in the hallway track convinced me that it was wrong. I'll send another to handle it properly in mke2fs.conf, though. Thanks, Eric > This patch also adds the discard option into the default mke2fs.conf > file; although it could be set, it was not in the template. > > Signed-off-by: Eric Sandeen > --- > > V2: handle discard disable via "-K" since it's parsed *before* we get > the default. The extended options are parsed later, and will override > the mke2fs.conf default without problems. > > diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in > index 023ba49..a005eca 100644 > --- a/misc/mke2fs.8.in > +++ b/misc/mke2fs.8.in > @@ -277,11 +277,11 @@ Attempt to discard blocks at mkfs time (discarding blocks initially is useful > on solid state devices and sparse / thin-provisioned storage). When the device > advertises that discard also zeroes data (any subsequent read after the discard > and before write returns zero), then mark all not-yet-zeroed inode tables as > -zeroed. This significantly speeds up filesystem initialization. This is set > -as default. > +zeroed. This significantly speeds up filesystem initialization. This is disabled > +by default. > .TP > .BI nodiscard > -Do not attempt to discard blocks at mkfs time. > +Do not attempt to discard blocks at mkfs time. This is the default. > .TP > .BI quotatype > Specify which quota type ('usr' or 'grp') is to be initialized. This > diff --git a/misc/mke2fs.c b/misc/mke2fs.c > index bbf477a..fa11da6 100644 > --- a/misc/mke2fs.c > +++ b/misc/mke2fs.c > @@ -84,7 +84,7 @@ int cflag; > int verbose; > int quiet; > int super_only; > -int discard = 1; /* attempt to discard device before fs creation */ > +int discard; /* attempt to discard device before fs creation? */ > int direct_io; > int force; > int noaction; > @@ -1266,6 +1266,7 @@ static void PRS(int argc, char *argv[]) > double reserved_ratio = -1.0; > int lsector_size = 0, psector_size = 0; > int show_version_only = 0; > + int nodiscard = 0; > unsigned long long num_inodes = 0; /* unsigned long long to catch too-large input */ > errcode_t retval; > char * oldpath = getenv("PATH"); > @@ -1444,7 +1445,7 @@ profile_error: > "should not be used anymore. Use " > "\'-E nodiscard\' extended option " > "instead!\n")); > - discard = 0; > + nodiscard = 1; > break; > case 'j': > if (!journal_size) > @@ -1985,7 +1986,8 @@ profile_error: > lazy_itable_init = get_bool_from_profile(fs_types, > "lazy_itable_init", > lazy_itable_init); > - discard = get_bool_from_profile(fs_types, "discard" , discard); > + /* nodiscard is set if -K was used, extended discard opts parsed later */ > + discard = nodiscard ? 0 : get_bool_from_profile(fs_types, "discard" , 0); > journal_flags |= get_bool_from_profile(fs_types, > "lazy_journal_init", 0) ? > EXT2_MKJOURNAL_LAZYINIT : 0; > diff --git a/misc/mke2fs.conf.in b/misc/mke2fs.conf.in > index 178733f..db6decb 100644 > --- a/misc/mke2fs.conf.in > +++ b/misc/mke2fs.conf.in > @@ -2,6 +2,7 @@ > base_features = sparse_super,filetype,resize_inode,dir_index,ext_attr > default_mntopts = acl,user_xattr > enable_periodic_fsck = 0 > + discard = 0 > blocksize = 4096 > inode_size = 256 > inode_ratio = 16384 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html