Messages in this thread | | | Subject | Re: [PATCH 1/2] md: fix WARN_ON if create symlink fail in bind_rdev_to_array() | From | Yu Kuai <> | Date | Mon, 25 Dec 2023 09:35:24 +0800 |
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Hi,
在 2023/12/25 9:11, Song Liu 写道: > On Thu, Dec 21, 2023 at 5:17 PM Li Nan <linan666@huaweicloud.com> wrote: >> >> >> >> 在 2023/12/22 2:58, Song Liu 写道: > [...] >>> In general, I would like to avoid adding flags if possible. >>> >> >> This flag is mainly used to fix deadlock in next patch. Or should we >> export bd_find_holder_disk()? Link hodler if it return NULL. >> just like: >> >> rdev_for_each_rcu >> if (!bd_find_holder_disk) >> bd_link_disk_holder > > I was thinking we will not need the flag if we fail bind_rdev_to_array() > on error (below). > >> >> >>>> }; >>>> >>>> static inline int is_badblock(struct md_rdev *rdev, sector_t s, int sectors, >>>> diff --git a/drivers/md/md.c b/drivers/md/md.c >>>> index e05858653a41..d6612b922c76 100644 >>>> --- a/drivers/md/md.c >>>> +++ b/drivers/md/md.c >>>> @@ -2526,7 +2526,8 @@ static int bind_rdev_to_array(struct md_rdev *rdev, struct mddev *mddev) >>>> sysfs_get_dirent_safe(rdev->kobj.sd, "bad_blocks"); >>>> >>>> list_add_rcu(&rdev->same_set, &mddev->disks); >>>> - bd_link_disk_holder(rdev->bdev, mddev->gendisk); >>>> + if (!bd_link_disk_holder(rdev->bdev, mddev->gendisk)) >>>> + set_bit(SymlinkCreated, &rdev->flags); >>> >>> Shall we just fail bind_rdev_to_array() if bd_link_disk_holder() >>> returns non-zero? >>> >> >> I keep this action because of commit 00bcb4ac7ee7 ("md: reduce >> dependence on sysfs."). Fail bind_rdev_to_array is good to me. > > I wonder whether the assumption in 00bcb4ac7ee7 is still true. If > bd_link_disk_holder() fails for valid reasons, we need to handle it > properly (set a flag, check the flag on unlink, etc.). If we only fail > bd_link_disk_holder() on extreme cases (ENOMEM, etc.), we can > just fail bind_rdev_to_array().
I totally agree! Currently, bd_link_disk_holder() from md won't return -EINVAL, it will return -ENOMEM or -ENODEV if underlying disk is deleted, which means bind_rdev_to_array() should fail as well.
The only problem is that this will make next patch more complicated, but I think this can be solved.
Thanks, Kuai > > Thanks, > Song > . >
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