Messages in this thread | | | Subject | Re: [PATCH] md: Don't clear MD_CLOSING when the raid is about to stop | From | Yu Kuai <> | Date | Tue, 12 Dec 2023 11:21:28 +0800 |
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Hi,
在 2023/12/11 17:56, Mariusz Tkaczyk 写道: > On Mon, 11 Dec 2023 16:17:14 +0800 > linan666@huaweicloud.com wrote: > >> From: Li Nan <linan122@huawei.com> >> >> The raid should not be opened anymore when it is about to be stopped. >> However, other processes can open it again if the flag MD_CLOSING is >> cleared before exiting. From now on, this flag will not be cleared when >> the raid will be stopped. >> >> Fixes: 065e519e71b2 ("md: MD_CLOSING needs to be cleared after called >> md_set_readonly or do_md_stop") Signed-off-by: Li Nan <linan122@huawei.com> > > Hello Li Nan, > I was there when I needed to fix this: > https://git.kernel.org/pub/scm/linux/kernel/git/song/md.git/commit/?h=md-next&id=c8870379a21fbd9ad14ca36204ccfbe9d25def43 > > For sure, you have to consider applying same solution for array_store "clear". > Minor nit below. > > Thanks, > Mariusz > >> --- >> drivers/md/md.c | 8 +++----- >> 1 file changed, 3 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/md/md.c b/drivers/md/md.c >> index 4e9fe5cbeedc..ebdfc9068a60 100644 >> --- a/drivers/md/md.c >> +++ b/drivers/md/md.c >> @@ -6238,7 +6238,6 @@ static void md_clean(struct mddev *mddev) >> mddev->persistent = 0; >> mddev->level = LEVEL_NONE; >> mddev->clevel[0] = 0; >> - mddev->flags = 0; > > I recommend (safety recommendation): > mddev->flags = MD_CLOSING;
Taking a look I think both MD_CLOSING and MD_DELETED should not be cleared, however, there is no guarantee that MD_CLOSING will be set before md_clean, because mdadm can be removed without running. Hence I think just set MD_CLOSING is werid.
I think the proper way is to keep MD_CLOSING and MD_DELETED if they are set. However, there is no such api to clear other bits at once. Since we're not expecting anyone else to write flags, following maybe acceptable:
mddev->flags &= BIT_ULL_MASK(MD_CLOSING) | BIT_ULL_MASK(MD_DELETED);
Or after making sure other flags cannot race, this patch is ok.
Thanks, Kuai
> > Unless you can prove that other flags cannot race. > >> mddev->sb_flags = 0; >> mddev->ro = MD_RDWR; >> mddev->metadata_type[0] = 0; > > . >
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