WHATS_NEW           |  1 +

 lib/device/bcache.c | 10 +++++++++-

 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/WHATS_NEW b/WHATS_NEW

index 47db4a3..8063364 100644

--- a/WHATS_NEW

+++ b/WHATS_NEW

@@ -10,6 +10,7 @@ Version 2.02.182 -

   Fix change of monitoring in clustered volumes.

   Fix lvconvert striped/raid0/raid0_meta -> raid6 regression.

   Add After=rbdmap.service to {lvm2-activation-net,blk-availability}.service.

+  Reduce max concurrent aios to avoid EMFILE with many devices.

   Fix lvconvert conversion attempts to linear.

   Fix lvconvert raid0/raid0_meta -> striped regression.

   Fix lvconvert --splitmirror for mirror type (2.02.178).

diff --git a/lib/device/bcache.c b/lib/device/bcache.c

index 6886b74..7384a32 100644

--- a/lib/device/bcache.c

+++ b/lib/device/bcache.c

@@ -253,7 +253,15 @@ static bool _async_issue(struct io_engine *ioe, enum dir d, int fd,

 	return true;

 }

-#define MAX_IO 1024

+/*

+ * MAX_IO is returned to the layer above via bcache_max_prefetches() which

+ * tells the caller how many devices to submit io for concurrently.  There will

+ * be an open file descriptor for each of these, so keep it low enough to avoid

+ * reaching the default max open file limit (1024) when there are over 1024

+ * devices being scanned.

+ */

+

+#define MAX_IO 256

 #define MAX_EVENT 64

 static bool _async_wait(struct io_engine *ioe, io_complete_fn fn)