md: set and test the ->persistent flag for md devices more consistently (1ec4a939) · Commits · 戴 / test

If you try to start an array for which the number of raid disks is listed as zero, md will currently try to read metadata off any devices that have been given. This was done because the value of raid_disks is used to signal whether array details have been provided by userspace (raid_disks > 0) or must be read from the devices (raid_disks == 0). However for an array without persistent metadata (or with externally managed metadata) this is the wrong thing to do. So we add a test in do_md_run to give an error if raid_disks is zero for non-persistent arrays. This requires that mddev->persistent is set corrently at this point, which it currently isn't for in-kernel autodetected arrays. So set ->persistent for autodetect arrays, and remove the settign in super_*_validate which is now redundant. Also clear ->persistent when stopping an array so it is consistently zero when starting an array. Signed-off-by:

Neil Brown <neilb@suse.de> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

drivers/md/md.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -779,7 +779,6 @@ static int super_90_validate(mddev_t mddev, mdk_rdev_t rdev)
		mddev->major_version = 0;
		mddev->minor_version = sb->minor_version;
		mddev->patch_version = sb->patch_version;
		mddev->persistent = 1;
		mddev->external = 0;
		mddev->chunk_size = sb->chunk_size;
		mddev->ctime = sb->ctime;
		@@ -1159,7 +1158,6 @@ static int super_1_validate(mddev_t mddev, mdk_rdev_t rdev)
		if (mddev->raid_disks == 0) {
		mddev->major_version = 1;
		mddev->patch_version = 0;
		mddev->persistent = 1;
		mddev->external = 0;
		mddev->chunk_size = le32_to_cpu(sb->chunksize) << 9;
		mddev->ctime = le64_to_cpu(sb->ctime) & ((1ULL << 32)-1);
		@@ -3213,8 +3211,11 @@ static int do_md_run(mddev_t * mddev)
		/*
		* Analyze all RAID superblock(s)
		*/
		if (!mddev->raid_disks)
		if (!mddev->raid_disks) {
		if (!mddev->persistent)
		return -EINVAL;
		analyze_sbs(mddev);
		}

		chunk_size = mddev->chunk_size;

		@@ -3621,6 +3622,7 @@ static int do_md_stop(mddev_t * mddev, int mode)
		mddev->resync_max = MaxSector;
		mddev->reshape_position = MaxSector;
		mddev->external = 0;
		mddev->persistent = 0;

		} else if (mddev->pers)
		printk(KERN_INFO "md: %s switched to read-only mode.\n",
		@@ -3729,6 +3731,7 @@ static void autorun_devices(int part)
		mddev_unlock(mddev);
		} else {
		printk(KERN_INFO "md: created %s\n", mdname(mddev));
		mddev->persistent = 1;
		ITERATE_RDEV_GENERIC(candidates,rdev,tmp) {
		list_del_init(&rdev->same_set);
		if (bind_rdev_to_array(rdev, mddev))

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