Commit 4bbf3771 authored by NeilBrown's avatar NeilBrown
Browse files

md: Relax minimum size restrictions on chunk_size. 



Currently, the 'chunk_size' of an array must be at-least PAGE_SIZE.

This makes moving an array to a machine with a larger PAGE_SIZE, or
changing the kernel to use a larger PAGE_SIZE, can stop an array from
working.

For RAID10 and RAID4/5/6, this is non-trivial to fix as the resync
process works on whole pages at a time, and assumes them to be wholly
within a stripe.  For other raid personalities, this restriction is
not needed at all and can be dropped.

So remove the test on chunk_size from common can, and add it in just
the places where it is needed: raid10 and raid4/5/6.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent d710e138

drivers/md/md.c

+1 −6
Original line number Diff line number Diff line
@@ -3520,17 +3520,12 @@ static int do_md_run(mddev_t * mddev) 
			return -EINVAL;

		}

		/*

		 * chunk-size has to be a power of 2 and multiples of PAGE_SIZE

		 * chunk-size has to be a power of 2

		 */

		if ( (1 << ffz(~chunk_size)) != chunk_size) {

			printk(KERN_ERR "chunk_size of %d not valid\n", chunk_size);

			return -EINVAL;

		}

		if (chunk_size < PAGE_SIZE) {

			printk(KERN_ERR "too small chunk_size: %d < %ld\n",

				chunk_size, PAGE_SIZE);

			return -EINVAL;

		}



		/* devices must have minimum size of one chunk */

		rdev_for_each(rdev, tmp, mddev) {

drivers/md/raid10.c

+3 −2
Original line number Diff line number Diff line
@@ -2028,8 +2028,9 @@ static int run(mddev_t *mddev) 
	int nc, fc, fo;

	sector_t stride, size;



	if (mddev->chunk_size == 0) {

		printk(KERN_ERR "md/raid10: non-zero chunk size required.\n");

	if (mddev->chunk_size < PAGE_SIZE) {

		printk(KERN_ERR "md/raid10: chunk size must be "

		       "at least PAGE_SIZE(%ld).\n", PAGE_SIZE);

		return -EINVAL;

	}

drivers/md/raid5.c

+7 −0
Original line number Diff line number Diff line
@@ -4007,6 +4007,13 @@ static int run(mddev_t *mddev) 
		return -EIO;

	}



	if (mddev->chunk_size < PAGE_SIZE) {

		printk(KERN_ERR "md/raid5: chunk_size must be at least "

		       "PAGE_SIZE but %d < %ld\n",

		       mddev->chunk_size, PAGE_SIZE);

		return -EINVAL;

	}



	if (mddev->reshape_position != MaxSector) {

		/* Check that we can continue the reshape.

		 * Currently only disks can change, it must

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