From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Darrick J. Wong" Subject: [RFC PATCH 1/2] bdi: Create a flag to indicate that a backing device needs stable page writes Date: Fri, 26 Oct 2012 18:35:24 -0700 Message-ID: <20121027013524.GA19591@blackbox.djwong.org> References: <20121026101909.GB19617@blackbox.djwong.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4 , linux-fsdevel To: "Theodore Ts'o" Return-path: Received: from userp1050.oracle.com ([156.151.31.82]:23838 "EHLO userp1050.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758290Ab2J0Bgw (ORCPT ); Fri, 26 Oct 2012 21:36:52 -0400 Content-Disposition: inline In-Reply-To: <20121026101909.GB19617@blackbox.djwong.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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 --- 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, };