From: Jan Kara Subject: Re: [RFC PATCH 1/2] bdi: Create a flag to indicate that a backing device needs stable page writes Date: Mon, 29 Oct 2012 19:13:58 +0100 Message-ID: <20121029181358.GG18767@quack.suse.cz> References: <20121026101909.GB19617@blackbox.djwong.org> <20121027013524.GA19591@blackbox.djwong.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Theodore Ts'o , linux-ext4 , linux-fsdevel To: "Darrick J. Wong" Return-path: Received: from cantor2.suse.de ([195.135.220.15]:44421 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932181Ab2J2SOA (ORCPT ); Mon, 29 Oct 2012 14:14:00 -0400 Content-Disposition: inline In-Reply-To: <20121027013524.GA19591@blackbox.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri 26-10-12 18:35:24, Darrick J. Wong wrote: > This creates BDI_CAP_STABLE_WRITES, which indicates that a device requires > stable page writes. It also plumbs in a sysfs attribute so that admins can > check the device status. > > Signed-off-by: Darrick J. Wong I guess Jens Axboe would be the best target for this patch (so that he can merge it). The patch looks OK to me. You can add: Reviewed-by: Jan Kara Honza > --- > > block/blk-integrity.c | 8 ++++++++ > include/linux/backing-dev.h | 6 ++++++ > mm/backing-dev.c | 11 +++++++++++ > 3 files changed, 25 insertions(+) > > diff --git a/block/blk-integrity.c b/block/blk-integrity.c > index da2a818..d05d7b3 100644 > --- a/block/blk-integrity.c > +++ b/block/blk-integrity.c > @@ -384,6 +384,7 @@ EXPORT_SYMBOL(blk_integrity_is_initialized); > int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template) > { > struct blk_integrity *bi; > + struct backing_dev_info *bdi; > > BUG_ON(disk == NULL); > > @@ -420,6 +421,9 @@ int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template) > } else > bi->name = bi_unsupported_name; > > + bdi = &disk->queue->backing_dev_info; > + bdi->capabilities |= BDI_CAP_STABLE_WRITES; > + > return 0; > } > EXPORT_SYMBOL(blk_integrity_register); > @@ -434,10 +438,14 @@ EXPORT_SYMBOL(blk_integrity_register); > void blk_integrity_unregister(struct gendisk *disk) > { > struct blk_integrity *bi; > + struct backing_dev_info *bdi; > > if (!disk || !disk->integrity) > return; > > + bdi = &disk->queue->backing_dev_info; > + bdi->capabilities &= ~BDI_CAP_STABLE_WRITES; > + > bi = disk->integrity; > > kobject_uevent(&bi->kobj, KOBJ_REMOVE); > diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h > index 2a9a9ab..b82a8bb 100644 > --- a/include/linux/backing-dev.h > +++ b/include/linux/backing-dev.h > @@ -253,6 +253,7 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); > #define BDI_CAP_EXEC_MAP 0x00000040 > #define BDI_CAP_NO_ACCT_WB 0x00000080 > #define BDI_CAP_SWAP_BACKED 0x00000100 > +#define BDI_CAP_STABLE_WRITES 0x00000200 > > #define BDI_CAP_VMFLAGS \ > (BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP) > @@ -307,6 +308,11 @@ long wait_iff_congested(struct zone *zone, int sync, long timeout); > int pdflush_proc_obsolete(struct ctl_table *table, int write, > void __user *buffer, size_t *lenp, loff_t *ppos); > > +static inline bool bdi_cap_stable_writes(struct backing_dev_info *bdi) > +{ > + return bdi->capabilities & BDI_CAP_STABLE_WRITES; > +} > + > static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi) > { > return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK); > diff --git a/mm/backing-dev.c b/mm/backing-dev.c > index d3ca2b3..a2f4c08 100644 > --- a/mm/backing-dev.c > +++ b/mm/backing-dev.c > @@ -221,12 +221,23 @@ static ssize_t max_ratio_store(struct device *dev, > } > BDI_SHOW(max_ratio, bdi->max_ratio) > > +static ssize_t stable_page_writes_show(struct device *dev, > + struct device_attribute *attr, char *page) > +{ > + struct backing_dev_info *bdi = dev_get_drvdata(dev); > + > + return snprintf(page, PAGE_SIZE-1, "%d\n", > + bdi->capabilities & BDI_CAP_STABLE_WRITES ? 1 : 0); > +} > + > #define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store) > +#define __ATTR_RO(attr) __ATTR(attr, 0444, attr##_show, NULL) > > static struct device_attribute bdi_dev_attrs[] = { > __ATTR_RW(read_ahead_kb), > __ATTR_RW(min_ratio), > __ATTR_RW(max_ratio), > + __ATTR_RO(stable_page_writes), > __ATTR_NULL, > }; > > -- > 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 -- Jan Kara SUSE Labs, CR