From 0a927c2f02a2437a57679527e42ab7cbfa14efb1 Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@redhat.com>
Date: Tue, 21 Jul 2015 13:20:46 -0400
Subject: [PATCH 1/5] dm thin: return -ENOSPC when erroring retry list due to
 out of data space

Otherwise -EIO would be returned when -ENOSPC should be used
consistently.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
 drivers/md/dm-thin.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 1c50c580215c8..d2bbe8cc1e978 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -666,16 +666,21 @@ static void requeue_io(struct thin_c *tc)
 	requeue_deferred_cells(tc);
 }
 
-static void error_retry_list(struct pool *pool)
+static void error_retry_list_with_code(struct pool *pool, int error)
 {
 	struct thin_c *tc;
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(tc, &pool->active_thins, list)
-		error_thin_bio_list(tc, &tc->retry_on_resume_list, -EIO);
+		error_thin_bio_list(tc, &tc->retry_on_resume_list, error);
 	rcu_read_unlock();
 }
 
+static void error_retry_list(struct pool *pool)
+{
+	return error_retry_list_with_code(pool, -EIO);
+}
+
 /*
  * This section of code contains the logic for processing a thin device's IO.
  * Much of the code depends on pool object resources (lists, workqueues, etc)
@@ -2297,7 +2302,7 @@ static void do_no_space_timeout(struct work_struct *ws)
 	if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space) {
 		pool->pf.error_if_no_space = true;
 		notify_of_pool_mode_change_to_oods(pool);
-		error_retry_list(pool);
+		error_retry_list_with_code(pool, -ENOSPC);
 	}
 }
 

From 134bf30c06f057d6b8d90132e8f8b3cd2be79572 Mon Sep 17 00:00:00 2001
From: Colin Ian King <colin.king@canonical.com>
Date: Thu, 23 Jul 2015 16:47:59 +0100
Subject: [PATCH 2/5] dm cache policy smq: fix alloc_bitset check that always
 evaluates as false

static analysis by cppcheck has found a check on alloc_bitset that
always evaluates as false and hence never finds an allocation failure:

[drivers/md/dm-cache-policy-smq.c:1689]: (warning) Logical conjunction
  always evaluates to false: !EXPR && EXPR.

Fix this by removing the incorrect mq->cache_hit_bits check

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
 drivers/md/dm-cache-policy-smq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/dm-cache-policy-smq.c b/drivers/md/dm-cache-policy-smq.c
index b6f22651dd356..48a4a826ae076 100644
--- a/drivers/md/dm-cache-policy-smq.c
+++ b/drivers/md/dm-cache-policy-smq.c
@@ -1686,7 +1686,7 @@ static struct dm_cache_policy *smq_create(dm_cblock_t cache_size,
 
 	if (from_cblock(cache_size)) {
 		mq->cache_hit_bits = alloc_bitset(from_cblock(cache_size));
-		if (!mq->cache_hit_bits && mq->cache_hit_bits) {
+		if (!mq->cache_hit_bits) {
 			DMERR("couldn't allocate cache hit bitset");
 			goto bad_cache_hit_bits;
 		}

From 6ed443c07f1e7f819983422b16598facb152250d Mon Sep 17 00:00:00 2001
From: Baruch Siach <baruch@tkos.co.il>
Date: Sun, 5 Jul 2015 09:55:44 +0300
Subject: [PATCH 3/5] dm crypt: update wiki page URL

Cryptsetup moved to gitlab.  This is a leftover from commit e44f23b32dc7
(dm crypt: update URLs to new cryptsetup project page, 2015-04-05).

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
 drivers/md/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index b597273090724..bfec3bdfe5984 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -259,7 +259,7 @@ config DM_CRYPT
 	  the ciphers you're going to use in the cryptoapi configuration.
 
 	  For further information on dm-crypt and userspace tools see:
-	  <http://code.google.com/p/cryptsetup/wiki/DMCrypt>
+	  <https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt>
 
 	  To compile this code as a module, choose M here: the module will
 	  be called dm-crypt.

From 3508e6590d4729ac07f01f7ae2256c2f9dc738b8 Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@redhat.com>
Date: Wed, 29 Jul 2015 14:11:28 -0400
Subject: [PATCH 4/5] Revert "dm cache: do not wake_worker() in
 free_migration()"

This reverts commit 386cb7cdeeef97e0bf082a8d6bbfc07a2ccce07b.

Taking the wake_worker() out of free_migration() will slow writeback
dramatically, and hence adaptability.

Say we have 10k blocks that need writing back, but are only able to
issue 5 concurrently due to the migration bandwidth: it's imperative
that we wake_worker() immediately after migration completion; waiting
for the next 1 second wake up (via do_waker) means it'll take a long
time to write that all back.

Reported-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
 drivers/md/dm-cache-target.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index b680da5d7b93b..64e96a2bed589 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -424,6 +424,7 @@ static void free_migration(struct dm_cache_migration *mg)
 		wake_up(&cache->migration_wait);
 
 	mempool_free(mg, cache->migration_pool);
+	wake_worker(cache);
 }
 
 static int prealloc_data_structs(struct cache *cache, struct prealloc *p)

From 795e633a2dc6cbbeac68bc7f6006082150d38bb7 Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@redhat.com>
Date: Wed, 29 Jul 2015 13:48:23 -0400
Subject: [PATCH 5/5] dm cache: fix device destroy hang due to improper
 prealloc_used accounting

Commit 665022d72f9 ("dm cache: avoid calls to prealloc_free_structs() if
possible") introduced a regression that caused the removal of a DM cache
device to hang in cache_postsuspend()'s call to wait_for_migrations()
with the following stack trace:

  [<ffffffff81651457>] schedule+0x37/0x80
  [<ffffffffa041e21b>] cache_postsuspend+0xbb/0x470 [dm_cache]
  [<ffffffff810ba970>] ? prepare_to_wait_event+0xf0/0xf0
  [<ffffffffa0006f77>] dm_table_postsuspend_targets+0x47/0x60 [dm_mod]
  [<ffffffffa0001eb5>] __dm_destroy+0x215/0x250 [dm_mod]
  [<ffffffffa0004113>] dm_destroy+0x13/0x20 [dm_mod]
  [<ffffffffa00098cd>] dev_remove+0x10d/0x170 [dm_mod]
  [<ffffffffa00097c0>] ? dev_suspend+0x240/0x240 [dm_mod]
  [<ffffffffa0009f85>] ctl_ioctl+0x255/0x4d0 [dm_mod]
  [<ffffffff8127ac00>] ? SYSC_semtimedop+0x280/0xe10
  [<ffffffffa000a213>] dm_ctl_ioctl+0x13/0x20 [dm_mod]
  [<ffffffff811fd432>] do_vfs_ioctl+0x2d2/0x4b0
  [<ffffffff81117d5f>] ? __audit_syscall_entry+0xaf/0x100
  [<ffffffff81022636>] ? do_audit_syscall_entry+0x66/0x70
  [<ffffffff811fd689>] SyS_ioctl+0x79/0x90
  [<ffffffff81023e58>] ? syscall_trace_leave+0xb8/0x110
  [<ffffffff81654f6e>] entry_SYSCALL_64_fastpath+0x12/0x71

Fix this by accounting for the call to prealloc_data_structs()
immediately _before_ the call as opposed to after.  This is needed
because it is possible to break out of the control loop after the call
to prealloc_data_structs() but before prealloc_used was set to true.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
 drivers/md/dm-cache-target.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 64e96a2bed589..1fe93cfea7d30 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -1967,6 +1967,7 @@ static void process_deferred_bios(struct cache *cache)
 		 * this bio might require one, we pause until there are some
 		 * prepared mappings to process.
 		 */
+		prealloc_used = true;
 		if (prealloc_data_structs(cache, &structs)) {
 			spin_lock_irqsave(&cache->lock, flags);
 			bio_list_merge(&cache->deferred_bios, &bios);
@@ -1982,7 +1983,6 @@ static void process_deferred_bios(struct cache *cache)
 			process_discard_bio(cache, &structs, bio);
 		else
 			process_bio(cache, &structs, bio);
-		prealloc_used = true;
 	}
 
 	if (prealloc_used)
@@ -2011,6 +2011,7 @@ static void process_deferred_cells(struct cache *cache)
 		 * this bio might require one, we pause until there are some
 		 * prepared mappings to process.
 		 */
+		prealloc_used = true;
 		if (prealloc_data_structs(cache, &structs)) {
 			spin_lock_irqsave(&cache->lock, flags);
 			list_splice(&cells, &cache->deferred_cells);
@@ -2019,7 +2020,6 @@ static void process_deferred_cells(struct cache *cache)
 		}
 
 		process_cell(cache, &structs, cell);
-		prealloc_used = true;
 	}
 
 	if (prealloc_used)
@@ -2081,6 +2081,7 @@ static void writeback_some_dirty_blocks(struct cache *cache)
 		if (policy_writeback_work(cache->policy, &oblock, &cblock, busy))
 			break; /* no work to do */
 
+		prealloc_used = true;
 		if (prealloc_data_structs(cache, &structs) ||
 		    get_cell(cache, oblock, &structs, &old_ocell)) {
 			policy_set_dirty(cache->policy, oblock);
@@ -2088,7 +2089,6 @@ static void writeback_some_dirty_blocks(struct cache *cache)
 		}
 
 		writeback(cache, &structs, oblock, cblock, old_ocell);
-		prealloc_used = true;
 	}
 
 	if (prealloc_used)