md: don't report active array_state until after revalidate_disk() completes. (9d4b45d6) · Commits · 戴 / test

Until revalidate_disk() has completed, the size of a new md array will appear to be zero. So we shouldn't report, through array_state, that the array is active until that time. udev rules check array_state to see if the array is ready. As soon as it appear to be zero, fsck can be run. If it find the size to be zero, it will fail. So add a new flag to provide an interlock between do_md_run() and array_state_show(). This flag is set while do_md_run() is active and it prevents array_state_show() from reporting that the array is active. Before do_md_run() is called, ->pers will be NULL so array is definitely not active. After do_md_run() is called, revalidate_disk() will have run and the array will be completely ready. We also move various sysfs_notify*() calls out of md_run() into do_md_run() after MD_NOT_READY is cleared. This ensure the information is ready before the notification is sent. Prior to v4.12, array_state_show() was called with the mddev->reconfig_mutex held, which provided exclusion with do_md_run(). Note that MD_NOT_READY cleared twice. This is deliberate to cover both success and error paths with minimal noise. Fixes: ("md: remove mddev_lock() from md_attr_show()") Cc: stable@vger.kernel.org (v4.12++) Signed-off-by:

NeilBrown <neilb@suse.com> Signed-off-by:

Song Liu <songliubraving@fb.com>

drivers/md/md.c

+7 −4

Original line number	Diff line number	Diff line
		@@ -4179,7 +4179,7 @@ array_state_show(struct mddev mddev, char page)
		{
		enum array_state st = inactive;

		if (mddev->pers)
		if (mddev->pers && !test_bit(MD_NOT_READY, &mddev->flags))
		switch(mddev->ro) {
		case 1:
		st = readonly;
		@@ -5776,9 +5776,6 @@ int md_run(struct mddev *mddev)
		md_update_sb(mddev, 0);

		md_new_event(mddev);
		sysfs_notify_dirent_safe(mddev->sysfs_state);
		sysfs_notify_dirent_safe(mddev->sysfs_action);
		sysfs_notify(&mddev->kobj, NULL, "degraded");
		return 0;

		bitmap_abort:
		@@ -5799,6 +5796,7 @@ static int do_md_run(struct mddev *mddev)
		{
		int err;

		set_bit(MD_NOT_READY, &mddev->flags);
		err = md_run(mddev);
		if (err)
		goto out;
		@@ -5819,9 +5817,14 @@ static int do_md_run(struct mddev *mddev)

		set_capacity(mddev->gendisk, mddev->array_sectors);
		revalidate_disk(mddev->gendisk);
		clear_bit(MD_NOT_READY, &mddev->flags);
		mddev->changed = 1;
		kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
		sysfs_notify_dirent_safe(mddev->sysfs_state);
		sysfs_notify_dirent_safe(mddev->sysfs_action);
		sysfs_notify(&mddev->kobj, NULL, "degraded");
		out:
		clear_bit(MD_NOT_READY, &mddev->flags);
		return err;
		}

drivers/md/md.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -248,6 +248,9 @@ enum mddev_flags {
		MD_UPDATING_SB, /* md_check_recovery is updating the metadata
		* without explicitly holding reconfig_mutex.
		*/
		MD_NOT_READY, /* do_md_run() is active, so 'array_state'
		* must not report that array is ready yet
		*/
		};

		enum mddev_sb_flags {

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