md: cleanup mddev flag clear for takeover

Commit 6995f0b (md: takeover should clear unrelated bits) clear
unrelated bits, but it's quite fragile. To avoid error in the future,
define a macro for unsupported mddev flags for each raid type and use it
to clear unsupported mddev flags. This should be less error-prone.

Suggested-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index a162fedeb51a..848365d474f3 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -26,6 +26,11 @@
 #include "raid0.h"
 #include "raid5.h"
 
+#define UNSUPPORTED_MDDEV_FLAGS         \
+        ((1L << MD_HAS_JOURNAL) |       \
+         (1L << MD_JOURNAL_CLEAN) |     \
+         (1L << MD_FAILFAST_SUPPORTED))
+
 static int raid0_congested(struct mddev *mddev, int bits)
 {
         struct r0conf *conf = mddev->private;
@@ -539,8 +544,7 @@ static void *raid0_takeover_raid45(struct mddev *mddev)
         mddev->delta_disks = -1;
         /* make sure it will be not marked as dirty */
         mddev->recovery_cp = MaxSector;
-        clear_bit(MD_HAS_JOURNAL, &mddev->flags);
-        clear_bit(MD_JOURNAL_CLEAN, &mddev->flags);
+        mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
 
         create_strip_zones(mddev, &priv_conf);
 
@@ -583,7 +587,7 @@ static void *raid0_takeover_raid10(struct mddev *mddev)
         mddev->degraded = 0;
         /* make sure it will be not marked as dirty */
         mddev->recovery_cp = MaxSector;
-        clear_bit(MD_FAILFAST_SUPPORTED, &mddev->flags);
+        mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
 
         create_strip_zones(mddev, &priv_conf);
         return priv_conf;
@@ -626,7 +630,7 @@ static void *raid0_takeover_raid1(struct mddev *mddev)
         mddev->raid_disks = 1;
         /* make sure it will be not marked as dirty */
         mddev->recovery_cp = MaxSector;
-        clear_bit(MD_FAILFAST_SUPPORTED, &mddev->flags);
+        mddev_clear_unsupported_flags(mddev, UNSUPPORTED_MDDEV_FLAGS);
 
         create_strip_zones(mddev, &priv_conf);
         return priv_conf;