path: root/drivers/md/md.c
diff options
authorNeilBrown <neilb@suse.com>2015-12-21 11:01:21 +1100
committerNeilBrown <neilb@suse.com>2015-12-21 11:10:06 +1100
commit312045eef985b61d74c28047ecd8eca6719d9516 (patch)
tree10e0c0b1ea968e006a35180d2e18bf412da8950b /drivers/md/md.c
parent9f7e43278605a0daf4edf7025c52c25e9ace6875 (diff)
md: remove check for MD_RECOVERY_NEEDED in action_store.
md currently doesn't allow a 'sync_action' such as 'reshape' to be set while MD_RECOVERY_NEEDED is set. This s a problem, particularly since commit 738a273806ee as that can cause ->check_shape to call mddev_resume() which sets MD_RECOVERY_NEEDED. So by the time we come to start 'reshape' it is very likely that MD_RECOVERY_NEEDED is still set. Testing for this flag is not really needed and is in any case very racy as it can be set at any moment - asynchronously. Any race between setting a sync_action and setting MD_RECOVERY_NEEDED must already be handled properly in some locked code, probably md_check_recovery(), so remove the test here. The test on MD_RECOVERY_RUNNING is also racy in the 'reshape' case so we should test it again after getting mddev_lock(). As this fixes a race and a regression which can cause 'reshape' to fail, it is suitable for -stable kernels since 4.1 Reported-by: Xiao Ni <xni@redhat.com> Fixes: 738a273806ee ("md/raid5: fix allocation of 'scribble' array.") Cc: stable@vger.kernel.org (v4.1+) Signed-off-by: NeilBrown <neilb@suse.com>
Diffstat (limited to 'drivers/md/md.c')
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index dbedc58d8c00..61aacab424cf 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4326,8 +4326,7 @@ action_store(struct mddev *mddev, const char *page, size_t len)
- } else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
- test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))
+ } else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
return -EBUSY;
else if (cmd_match(page, "resync"))
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
@@ -4340,8 +4339,12 @@ action_store(struct mddev *mddev, const char *page, size_t len)
return -EINVAL;
err = mddev_lock(mddev);
if (!err) {
- clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
- err = mddev->pers->start_reshape(mddev);
+ if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
+ err = -EBUSY;
+ else {
+ clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+ err = mddev->pers->start_reshape(mddev);
+ }
if (err)