From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: axboe@kernel.dk, lucho@ionkov.net, jack@suse.cz,
darrick.wong@oracle.com, ericvh@gmail.com,
viro@zeniv.linux.org.uk, rminnich@sandia.gov, tytso@mit.edu
Cc: martin.petersen@oracle.com, neilb@suse.de, david@fromorbit.com,
gnehzuil.liu@gmail.com, linux-kernel@vger.kernel.org,
hch@infradead.org, linux-fsdevel@vger.kernel.org,
adilger.kernel@dilger.ca, bharrosh@panasas.com,
jlayton@samba.org, akpm@linux-foundation.org,
linux-ext4@vger.kernel.org, hirofumi@mail.parknet.co.jp
Subject: [PATCH 1/6] bdi: Allow block devices to say that they require stable page writes
Date: Fri, 18 Jan 2013 17:12:38 -0800 [thread overview]
Message-ID: <20130119011238.20902.38730.stgit@blackbox.djwong.org> (raw)
In-Reply-To: <20130119011231.20902.55954.stgit@blackbox.djwong.org>
This creates a per-backing-device flag that tracks whether or not pages must be
held immutable during writeout. Eventually it will be used to waive
wait_for_page_writeback() if nothing requires stable pages.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
Documentation/ABI/testing/sysfs-class-bdi | 5 +++++
block/blk-integrity.c | 4 ++++
include/linux/backing-dev.h | 6 ++++++
mm/backing-dev.c | 11 +++++++++++
4 files changed, 26 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-class-bdi b/Documentation/ABI/testing/sysfs-class-bdi
index 5f50097..d773d56 100644
--- a/Documentation/ABI/testing/sysfs-class-bdi
+++ b/Documentation/ABI/testing/sysfs-class-bdi
@@ -48,3 +48,8 @@ max_ratio (read-write)
most of the write-back cache. For example in case of an NFS
mount that is prone to get stuck, or a FUSE mount which cannot
be trusted to play fair.
+
+stable_pages_required (read-only)
+
+ If set, the backing device requires that all pages comprising a write
+ request must not be changed until writeout is complete.
diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index da2a818..dabd221 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -420,6 +420,8 @@ int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template)
} else
bi->name = bi_unsupported_name;
+ disk->queue->backing_dev_info.capabilities |= BDI_CAP_STABLE_WRITES;
+
return 0;
}
EXPORT_SYMBOL(blk_integrity_register);
@@ -438,6 +440,8 @@ void blk_integrity_unregister(struct gendisk *disk)
if (!disk || !disk->integrity)
return;
+ disk->queue->backing_dev_info.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 12731a1..3504599 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -254,6 +254,7 @@ 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)
@@ -308,6 +309,11 @@ 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_pages_required(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..41733c5 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_pages_required_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_cap_stable_pages_required(bdi) ? 1 : 0);
+}
+
#define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store)
static struct device_attribute bdi_dev_attrs[] = {
__ATTR_RW(read_ahead_kb),
__ATTR_RW(min_ratio),
__ATTR_RW(max_ratio),
+ __ATTR_RO(stable_pages_required),
__ATTR_NULL,
};
next prev parent reply other threads:[~2013-01-19 1:14 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-19 1:12 [PATCH v2.5 0/3] mm/fs: Remove unnecessary waiting for stable pages Darrick J. Wong
2013-01-19 1:12 ` Darrick J. Wong [this message]
2013-01-19 1:12 ` [PATCH 2/6] mm: Only enforce stable page writes if the backing device requires it Darrick J. Wong
2013-01-19 1:12 ` [PATCH 3/6] 9pfs: Fix filesystem to wait for stable page writeback Darrick J. Wong
2013-01-19 1:13 ` [PATCH 4/6] block: Optionally snapshot page contents to provide stable pages during write Darrick J. Wong
2013-01-21 14:12 ` Jan Kara
2013-01-19 1:13 ` [PATCH 5/6] ocfs2: Wait for page writeback to provide stable pages Darrick J. Wong
2013-01-30 1:03 ` Joel Becker
2013-01-19 1:13 ` [PATCH 6/6] ubifs: " Darrick J. Wong
2013-01-23 21:43 ` Andrew Morton
2013-02-21 3:48 ` Darrick J. Wong
2013-02-21 9:36 ` Boaz Harrosh
2013-02-21 22:32 ` Andrew Morton
2013-02-21 22:40 ` Darrick J. Wong
-- strict thread matches above, loose matches on Subject: below --
2013-01-15 5:42 [PATCH v2.4 0/3] mm/fs: Remove unnecessary waiting for " Darrick J. Wong
2013-01-15 5:42 ` [PATCH 1/6] bdi: Allow block devices to say that they require stable page writes Darrick J. Wong
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