Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754106AbbGWPux (ORCPT ); Thu, 23 Jul 2015 11:50:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36619 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753490AbbGWPue (ORCPT ); Thu, 23 Jul 2015 11:50:34 -0400 Date: Thu, 23 Jul 2015 11:50:32 -0400 From: Mike Snitzer To: Dave Chinner Cc: Eric Sandeen , axboe@kernel.dk, linux-kernel@vger.kernel.org, xfs@oss.sgi.com, dm-devel@redhat.com, linux-fsdevel@vger.kernel.org, hch@lst.de, Vivek Goyal Subject: [RFC PATCH] block: dm thin: export how block device handles -ENOSPC Message-ID: <20150723155032.GA7246@redhat.com> References: <55AE6670.40903@redhat.com> <20150721174753.GA8563@redhat.com> <20150722000923.GB7943@dastard> <20150722010056.GC7943@dastard> <20150722014029.GA10628@redhat.com> <20150722023711.GD7943@dastard> <20150722133451.GB16842@redhat.com> <55AFC496.4000009@redhat.com> <20150723051043.GB3902@dastard> <20150723143352.GA23921@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150723143352.GA23921@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7229 Lines: 218 On Thu, Jul 23 2015 at 10:33P -0400, Mike Snitzer wrote: > If you just want to stub out the call to bdev_get_nospace_strategy() I > can crank through implementing it once I get a few minutes. I didn't use a 4th EOPNOTSUPP enum since if a device doesn't have any special -ENOSPC handling it'd implicitly be FAST_FAILS_IF_NOSPACE. But if I overlooked some need for it please let me know. >From 1def7c15911bf15dbee96217591856806bd94b80 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Thu, 23 Jul 2015 11:28:43 -0400 Subject: [PATCH] block: dm thin: export how block device handles -ENOSPC DM thin provisioning's handling of -ENOSPC from the underlying data device is configurable. Export this information so that upper layers (e.g. XFS) may train their -ENOSPC handling accordingly. By default all normal block devices won't have any specialized handling (FAST_FAILS_IF_NOSPACE), if the device queues IO for a specified time it will fail slowly (SLOW_FAILS_IF_NOSPACE), otherwise it queues IO indefinitely (NEVER_FAILS_IF_NOSPACE). Suggested-by: Dave Chinner Signed-off-by: Mike Snitzer --- drivers/md/dm-thin.c | 19 +++++++++++++++++-- drivers/md/dm.c | 33 +++++++++++++++++++++++++++++++++ fs/block_dev.c | 10 ++++++++++ include/linux/blkdev.h | 9 +++++++++ include/linux/device-mapper.h | 6 ++++++ 5 files changed, 75 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index d2bbe8c..11cbdf1 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -3953,7 +3953,7 @@ static struct target_type pool_target = { .name = "thin-pool", .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE | DM_TARGET_IMMUTABLE, - .version = {1, 16, 0}, + .version = {1, 17, 0}, .module = THIS_MODULE, .ctr = pool_ctr, .dtr = pool_dtr, @@ -4338,9 +4338,23 @@ static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits) limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */ } +static enum blk_nospace_strategy thin_get_nospace_strategy(struct dm_target *ti) +{ + struct thin_c *tc = ti->private; + struct pool *pool = tc->pool; + + if (pool->pf.error_if_no_space) + return FAST_FAILS_IF_NOSPACE; + + else if (!ACCESS_ONCE(no_space_timeout_secs)) + return NEVER_FAILS_IF_NOSPACE; + + return SLOW_FAILS_IF_NOSPACE; +} + static struct target_type thin_target = { .name = "thin", - .version = {1, 16, 0}, + .version = {1, 17, 0}, .module = THIS_MODULE, .ctr = thin_ctr, .dtr = thin_dtr, @@ -4353,6 +4367,7 @@ static struct target_type thin_target = { .merge = thin_merge, .iterate_devices = thin_iterate_devices, .io_hints = thin_io_hints, + .get_nospace_strategy = thin_get_nospace_strategy, }; /*----------------------------------------------------------------*/ diff --git a/drivers/md/dm.c b/drivers/md/dm.c index ab37ae1..226d856 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -597,6 +597,38 @@ out: return r; } +static enum blk_nospace_strategy dm_blk_get_nospace_strategy(struct block_device *bdev) +{ + struct mapped_device *md = bdev->bd_disk->private_data; + int srcu_idx; + struct dm_table *map; + struct dm_target *tgt; + enum blk_nospace_strategy nospace_strategy = FAST_FAILS_IF_NOSPACE; + + map = dm_get_live_table(md, &srcu_idx); + + if (!map || !dm_table_get_size(map)) + goto out; + + /* We only support devices that have a single target */ + if (dm_table_get_num_targets(map) != 1) + goto out; + + tgt = dm_table_get_target(map, 0); + if (!tgt->type->get_nospace_strategy) + goto out; + + if (dm_suspended_md(md)) + goto out; + + nospace_strategy = tgt->type->get_nospace_strategy(tgt); + +out: + dm_put_live_table(md, srcu_idx); + + return nospace_strategy; +} + static struct dm_io *alloc_io(struct mapped_device *md) { return mempool_alloc(md->io_pool, GFP_NOIO); @@ -3647,6 +3679,7 @@ static const struct block_device_operations dm_blk_dops = { .release = dm_blk_close, .ioctl = dm_blk_ioctl, .getgeo = dm_blk_getgeo, + .get_nospace_strategy = dm_blk_get_nospace_strategy, .owner = THIS_MODULE }; diff --git a/fs/block_dev.c b/fs/block_dev.c index 1982437..a492644 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -469,6 +469,16 @@ long bdev_direct_access(struct block_device *bdev, sector_t sector, } EXPORT_SYMBOL_GPL(bdev_direct_access); +enum blk_nospace_strategy bdev_get_nospace_strategy(struct block_device *bdev) +{ + const struct block_device_operations *ops = bdev->bd_disk->fops; + + if (!ops->get_nospace_strategy) + return FAST_FAILS_IF_NOSPACE; + return ops->get_nospace_strategy(bdev); +} +EXPORT_SYMBOL_GPL(bdev_get_nospace_strategy); + /* * pseudo-fs */ diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index d4068c17d..fab5482 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1549,6 +1549,12 @@ static inline bool blk_integrity_is_initialized(struct gendisk *g) #endif /* CONFIG_BLK_DEV_INTEGRITY */ +enum blk_nospace_strategy { + FAST_FAILS_IF_NOSPACE, /* immediate ENOSPC (no special handling) */ + SLOW_FAILS_IF_NOSPACE, /* queue IO for some time, then ENOSPC */ + NEVER_FAILS_IF_NOSPACE, /* queue IO forever */ +}; + struct block_device_operations { int (*open) (struct block_device *, fmode_t); void (*release) (struct gendisk *, fmode_t); @@ -1566,6 +1572,7 @@ struct block_device_operations { int (*getgeo)(struct block_device *, struct hd_geometry *); /* this callback is with swap_lock and sometimes page table lock held */ void (*swap_slot_free_notify) (struct block_device *, unsigned long); + enum blk_nospace_strategy (*get_nospace_strategy) (struct block_device *); struct module *owner; }; @@ -1576,6 +1583,8 @@ extern int bdev_write_page(struct block_device *, sector_t, struct page *, struct writeback_control *); extern long bdev_direct_access(struct block_device *, sector_t, void **addr, unsigned long *pfn, long size); +extern enum blk_nospace_strategy bdev_get_nospace_strategy(struct block_device *); + #else /* CONFIG_BLOCK */ struct block_device; diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 51cc1de..2e3c5d5 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -119,6 +119,11 @@ typedef void (*dm_io_hints_fn) (struct dm_target *ti, */ typedef int (*dm_busy_fn) (struct dm_target *ti); +/* + * Returns how the target handles -ENOSPC from lower layers. + */ +typedef enum blk_nospace_strategy (*dm_get_nospace_strategy_fn) (struct dm_target *ti); + void dm_error(const char *message); struct dm_dev { @@ -164,6 +169,7 @@ struct target_type { dm_busy_fn busy; dm_iterate_devices_fn iterate_devices; dm_io_hints_fn io_hints; + dm_get_nospace_strategy_fn get_nospace_strategy; /* For internal device-mapper use. */ struct list_head list; -- 2.3.2 (Apple Git-55) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/