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| author | NeilBrown <neilb@suse.com> | 2015-12-21 01:01:21 +0100 |
|---|---|---|
| committer | NeilBrown <neilb@suse.com> | 2015-12-21 01:10:06 +0100 |
| commit | 312045eef985b61d74c28047ecd8eca6719d9516 (patch) | |
| tree | 10e0c0b1ea968e006a35180d2e18bf412da8950b /drivers | |
| parent | Merge tag 'rtc-4.4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/abello... (diff) | |
| download | linux-312045eef985b61d74c28047ecd8eca6719d9516.tar.xz linux-312045eef985b61d74c28047ecd8eca6719d9516.zip | |
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')
| -rw-r--r-- | drivers/md/md.c | 11 |
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) } mddev_unlock(mddev); } - } 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); + } mddev_unlock(mddev); } if (err) |