From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Tue, 18 Nov 2014 19:43:48 +0000 (-0800)
Subject: 3.14-stable patches
X-Git-Tag: v3.10.61~33
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=27b1d4c515e8531a7beaf9c7ef4ed4243bfbdf25;p=thirdparty%2Fkernel%2Fstable-queue.git

3.14-stable patches

added patches:
	dm-thin-grab-a-virtual-cell-before-looking-up-the-mapping.patch
---

diff --git a/queue-3.14/dm-thin-grab-a-virtual-cell-before-looking-up-the-mapping.patch b/queue-3.14/dm-thin-grab-a-virtual-cell-before-looking-up-the-mapping.patch
new file mode 100644
index 00000000000..d7decef2c5c
--- /dev/null
+++ b/queue-3.14/dm-thin-grab-a-virtual-cell-before-looking-up-the-mapping.patch
@@ -0,0 +1,75 @@
+From c822ed967cba38505713d59ed40a114386ef6c01 Mon Sep 17 00:00:00 2001
+From: Joe Thornber <ejt@redhat.com>
+Date: Fri, 10 Oct 2014 09:41:09 +0100
+Subject: dm thin: grab a virtual cell before looking up the mapping
+
+From: Joe Thornber <ejt@redhat.com>
+
+commit c822ed967cba38505713d59ed40a114386ef6c01 upstream.
+
+Avoids normal IO racing with discard.
+
+Signed-off-by: Joe Thornber <ejt@redhat.com>
+Signed-off-by: Mike Snitzer <snitzer@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/md/dm-thin.c |   16 ++++++++++++----
+ 1 file changed, 12 insertions(+), 4 deletions(-)
+
+--- a/drivers/md/dm-thin.c
++++ b/drivers/md/dm-thin.c
+@@ -1704,6 +1704,14 @@ static int thin_bio_map(struct dm_target
+ 		return DM_MAPIO_SUBMITTED;
+ 	}
+ 
++	/*
++	 * We must hold the virtual cell before doing the lookup, otherwise
++	 * there's a race with discard.
++	 */
++	build_virtual_key(tc->td, block, &key);
++	if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
++		return DM_MAPIO_SUBMITTED;
++
+ 	r = dm_thin_find_block(td, block, 0, &result);
+ 
+ 	/*
+@@ -1727,13 +1735,10 @@ static int thin_bio_map(struct dm_target
+ 			 * shared flag will be set in their case.
+ 			 */
+ 			thin_defer_bio(tc, bio);
++			cell_defer_no_holder_no_free(tc, &cell1);
+ 			return DM_MAPIO_SUBMITTED;
+ 		}
+ 
+-		build_virtual_key(tc->td, block, &key);
+-		if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1, &cell_result))
+-			return DM_MAPIO_SUBMITTED;
+-
+ 		build_data_key(tc->td, result.block, &key);
+ 		if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2, &cell_result)) {
+ 			cell_defer_no_holder_no_free(tc, &cell1);
+@@ -1754,6 +1759,7 @@ static int thin_bio_map(struct dm_target
+ 			 * of doing so.
+ 			 */
+ 			handle_unserviceable_bio(tc->pool, bio);
++			cell_defer_no_holder_no_free(tc, &cell1);
+ 			return DM_MAPIO_SUBMITTED;
+ 		}
+ 		/* fall through */
+@@ -1764,6 +1770,7 @@ static int thin_bio_map(struct dm_target
+ 		 * provide the hint to load the metadata into cache.
+ 		 */
+ 		thin_defer_bio(tc, bio);
++		cell_defer_no_holder_no_free(tc, &cell1);
+ 		return DM_MAPIO_SUBMITTED;
+ 
+ 	default:
+@@ -1773,6 +1780,7 @@ static int thin_bio_map(struct dm_target
+ 		 * pool is switched to fail-io mode.
+ 		 */
+ 		bio_io_error(bio);
++		cell_defer_no_holder_no_free(tc, &cell1);
+ 		return DM_MAPIO_SUBMITTED;
+ 	}
+ }
diff --git a/queue-3.14/series b/queue-3.14/series
index 53521802c7e..ac2059d085b 100644
--- a/queue-3.14/series
+++ b/queue-3.14/series
@@ -41,3 +41,4 @@ drm-radeon-add-missing-crtc-unlock-when-setting-up-the-mc.patch
 arm-8198-1-make-kuser-helpers-depend-on-mmu.patch
 arm-8191-1-decompressor-ensure-i-side-picks-up-relocated-code.patch
 pinctrl-dra-dt-bindings-fix-output-pull-up-down.patch
+dm-thin-grab-a-virtual-cell-before-looking-up-the-mapping.patch