md: Remove the AllReserved flag for component devices. (f21e9ff7) · Commits · 戴 / test

This flag is not needed and is used badly. Devices that are included in a native-metadata array are reserved exclusively for that array - and currently have AllReserved set. They all are bd_claimed for the rdev and so cannot be shared. Devices that are included in external-metadata arrays can be shared among multiple arrays - providing there is no overlap. These are bd_claimed for md in general - not for a particular rdev. When changing the amount of a device that is used in an array we need to check for overlap. This currently includes a check on AllReserved So even without overlap, sharing with an AllReserved device is not allowed. However the bd_claim usage already precludes sharing with these devices, so the test on AllReserved is not needed. And in fact it is wrong. As this is the only use of AllReserved, simply remove all usage and definition of AllReserved. Signed-off-by:

NeilBrown <neilb@suse.de>

drivers/md/md.c

+5 −8

Original line number	Diff line number	Diff line
		@@ -1947,8 +1947,6 @@ static int lock_rdev(mdk_rdev_t *rdev, dev_t dev, int shared)
		__bdevname(dev, b));
		return PTR_ERR(bdev);
		}
		if (!shared)
		set_bit(AllReserved, &rdev->flags);
		rdev->bdev = bdev;
		return err;
		}
		@@ -2610,12 +2608,11 @@ rdev_size_store(mdk_rdev_t rdev, const char buf, size_t len)

		mddev_lock(mddev);
		list_for_each_entry(rdev2, &mddev->disks, same_set)
		if (test_bit(AllReserved, &rdev2->flags) \|\|
		(rdev->bdev == rdev2->bdev &&
		if (rdev->bdev == rdev2->bdev &&
		rdev != rdev2 &&
		overlaps(rdev->data_offset, rdev->sectors,
		rdev2->data_offset,
		rdev2->sectors))) {
		rdev2->sectors)) {
		overlap = 1;
		break;
		}

drivers/md/md.h

+0 −2

Original line number	Diff line number	Diff line
		@@ -93,8 +93,6 @@ struct mdk_rdev_s
		#define Faulty 1 /* device is known to have a fault */
		#define In_sync 2 /* device is in_sync with rest of array */
		#define WriteMostly 4 /* Avoid reading if at all possible */
		#define AllReserved 6 /* If whole device is reserved for
		* one array */
		#define AutoDetected 7 /* added by auto-detect */
		#define Blocked 8 /* An error occured on an externally
		* managed array, don't allow writes

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