[md PATCH 1/3] md: improve errno return when setting array_size

[md PATCH 1/3] md: improve errno return when setting array_size

[NeilBrown]

Instead of always returns EINVAL if anything goes wrong
when setting the array size, add the option of
  E2BIG
if the size requested is too large.  This makes it easier
for user-space to be sure what went wrong.

Signed-off-by: NeilBrown <neilb@suse.de>
---

 drivers/md/md.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index fccc834..cc46c11 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3680,7 +3680,7 @@ array_size_store(mddev_t *mddev, const char *buf, size_t len)
 		if (strict_blocks_to_sectors(buf, &sectors) < 0)
 			return -EINVAL;
 		if (mddev->pers && mddev->pers->size(mddev, 0, 0) < sectors)
-			return -EINVAL;
+			return -E2BIG;
 
 		mddev->external_size = 1;
 	}

[md PATCH 3/3] md: export 'frozen' resync state through sysfs

[NeilBrown]

The md resync engine has a 'frozen' state which ensures that
no resync/recovery.  This is used to avoid races.

Export this state through the 'sync_action' sysfs attribute
so that user-space can benefit and also avoid some races.

Signed-off-by: NeilBrown <neilb@suse.de>
---

 drivers/md/md.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index cc46c11..6683b9a 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3303,7 +3303,9 @@ static ssize_t
 action_show(mddev_t *mddev, char *page)
 {
 	char *type = "idle";
-	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
+	if (test_bit(MD_RECOVERY_FROZEN, &mddev->recovery))
+		type = "frozen";
+	else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
 	    (!mddev->ro && test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))) {
 		if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
 			type = "reshape";
@@ -3326,7 +3328,12 @@ action_store(mddev_t *mddev, const char *page, size_t len)
 	if (!mddev->pers || !mddev->pers->sync_request)
 		return -EINVAL;
 
-	if (cmd_match(page, "idle")) {
+	if (cmd_match(page, "frozen"))
+		set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+	else
+		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+
+	if (cmd_match(page, "idle") || cmd_match(page, "frozen")) {
 		if (mddev->sync_thread) {
 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
 			md_unregister_thread(mddev->sync_thread);

[md PATCH 2/3] md: bitmap: improve bitmap maintenance code.

[NeilBrown]

The code for checking which bits in the bitmap can be cleared
has 2 problems:
 1/ it repeatedly takes and drops a spinlock, where it would make
    more sense to just hold on to it most of the time.
 2/ it doesn't make use of some opportunities to skip large sections
    of the bitmap

This patch fixes those.  It will only affect CPU consumption, not
correctness.

Signed-off-by: NeilBrown <neilb@suse.de>
---

 drivers/md/bitmap.c |   13 +++++++------
 1 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 47c68bc..56df1ce 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -1097,14 +1097,12 @@ void bitmap_daemon_work(struct bitmap *bitmap)
 	}
 	bitmap->allclean = 1;
 
+	spin_lock_irqsave(&bitmap->lock, flags);
 	for (j = 0; j < bitmap->chunks; j++) {
 		bitmap_counter_t *bmc;
-		spin_lock_irqsave(&bitmap->lock, flags);
-		if (!bitmap->filemap) {
+		if (!bitmap->filemap)
 			/* error or shutdown */
-			spin_unlock_irqrestore(&bitmap->lock, flags);
 			break;
-		}
 
 		page = filemap_get_page(bitmap, j);
 
@@ -1121,6 +1119,8 @@ void bitmap_daemon_work(struct bitmap *bitmap)
 					write_page(bitmap, page, 0);
 					bitmap->allclean = 0;
 				}
+				spin_lock_irqsave(&bitmap->lock, flags);
+				j |= (PAGE_BITS - 1);
 				continue;
 			}
 
@@ -1181,9 +1181,10 @@ void bitmap_daemon_work(struct bitmap *bitmap)
 					ext2_clear_bit(file_page_offset(j), paddr);
 				kunmap_atomic(paddr, KM_USER0);
 			}
-		}
-		spin_unlock_irqrestore(&bitmap->lock, flags);
+		} else
+			j |= PAGE_COUNTER_MASK;
 	}
+	spin_unlock_irqrestore(&bitmap->lock, flags);
 
 	/* now sync the final page */
 	if (lastpage != NULL) {