On Sun, Mar 17 2019, Alexander Lyakas wrote: > Hi Zhilong Liu, Shaohua Li, > > In case of do_md_stop(), when we want to stop and disassemble the > array, why are we clearing MD_CLOSING? Then, after clearing this flag, > md_open will succeed. So MD_CLOSING flag is not serving its purpose, > to my understanding. How can we prevent md_open() to succeed after > do_md_stop()? If you want to understand MD_CLOSING, I suggest that you look through the "git log" history to see the comments in the comment that introduced or changed the flag. We don't want to prevent md_open() from succeeding after do_md_stop(). We only want to block it while do_md_stop() is completing its task. BTW Shaohua is no longer with us https://lwn.net/Articles/775861/ NeilBrown > > Thanks, > Alex. > > > > > On Mon, Apr 10, 2017 at 8:49 PM Shaohua Li <shli@xxxxxxxxxx> wrote: >> >> On Thu, Apr 06, 2017 at 11:16:33AM +0800, Zhilong Liu wrote: >> > From: NeilBrown <neilb@xxxxxxxx> >> > >> > if called md_set_readonly and set MD_CLOSING bit, the mddev cannot >> > be opened any more due to the MD_CLOING bit wasn't cleared. Thus it >> > needs to be cleared in md_ioctl after any call to md_set_readonly() >> > or do_md_stop(). >> > Fixes: af8d8e6f0315 ("md: changes for MD_STILL_CLOSED flag") >> > >> > Signed-off-by: NeilBrown <neilb@xxxxxxxx> >> > Signed-off-by: Zhilong Liu <zlliu@xxxxxxxx> >> >> thanks, applied! This one looks stable stuff too. >> >> > --- >> > >> > drivers/md/md.c | 5 +++++ >> > 1 file changed, 5 insertions(+) >> > >> > diff --git a/drivers/md/md.c b/drivers/md/md.c >> > index f6ae1d6..906a4bf 100644 >> > --- a/drivers/md/md.c >> > +++ b/drivers/md/md.c >> > @@ -6776,6 +6776,7 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode, >> > void __user *argp = (void __user *)arg; >> > struct mddev *mddev = NULL; >> > int ro; >> > + bool did_set_md_closing = false; >> > >> > if (!md_ioctl_valid(cmd)) >> > return -ENOTTY; >> > @@ -6865,7 +6866,9 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode, >> > err = -EBUSY; >> > goto out; >> > } >> > + WARN_ON_ONCE(test_bit(MD_CLOSING, &mddev->flags)); >> > set_bit(MD_CLOSING, &mddev->flags); >> > + did_set_md_closing = true; >> > mutex_unlock(&mddev->open_mutex); >> > sync_blockdev(bdev); >> > } >> > @@ -7058,6 +7061,8 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode, >> > mddev->hold_active = 0; >> > mddev_unlock(mddev); >> > out: >> > + if(did_set_md_closing) >> > + clear_bit(MD_CLOSING, &mddev->flags); >> > return err; >> > } >> > #ifdef CONFIG_COMPAT >> > -- >> > 2.6.6 >> > >> > -- >> > To unsubscribe from this list: send the line "unsubscribe linux-raid" in >> > the body of a message to majordomo@xxxxxxxxxxxxxxx >> > More majordomo info at http://vger.kernel.org/majordomo-info.html >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-raid" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html
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