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Commit 4d936ec1 authored by Michael J. Evans's avatar Michael J. Evans Committed by Linus Torvalds
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md: software Raid autodetect dev list not array 



In current release kernels the md module (Software RAID) uses a static
array (dev_t[128]) to store partition/device info temporarily for
autostart.

I discovered this (and that the devices are added as disks/partitions are
discovered at boot) while I was debugging why only one of my MD arrays would
come up whole, while all the others were short a disk.

I eventually discovered that it was enumerating through all of 9 of my 11 hds
(2 had only 4 partitions apiece) while the other 9 have 15 partitions (I
wanted 64 per drive...).  The last partition of the 8th drive in my 9 drive
raid 5 sets wasn't added, thus making the final md array short both a parity
and data disk, and it was started later, elsewhere.

This patch replaces that static array with a list.

[akpm@linux-foundation.org: removed unused var]
Signed-off-by: default avatarMichael J. Evans <mjevans1983@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a686cd89

drivers/md/md.c

+33 −9
Original line number Diff line number Diff line
@@ -5770,26 +5770,47 @@ static int __init md_init(void) 
 * Searches all registered partitions for autorun RAID arrays

 * at boot time.

 */

static dev_t detected_devices[128];

static int dev_cnt;



static LIST_HEAD(all_detected_devices);

struct detected_devices_node {

	struct list_head list;

	dev_t dev;

};



void md_autodetect_dev(dev_t dev)

{

	if (dev_cnt >= 0 && dev_cnt < 127)

		detected_devices[dev_cnt++] = dev;

	struct detected_devices_node *node_detected_dev;



	node_detected_dev = kzalloc(sizeof(*node_detected_dev), GFP_KERNEL);

	if (node_detected_dev) {

		node_detected_dev->dev = dev;

		list_add_tail(&node_detected_dev->list, &all_detected_devices);

	} else {

		printk(KERN_CRIT "md: md_autodetect_dev: kzalloc failed"

			", skipping dev(%d,%d)\n", MAJOR(dev), MINOR(dev));

	}

}





static void autostart_arrays(int part)

{

	mdk_rdev_t *rdev;

	int i;

	struct detected_devices_node *node_detected_dev;

	dev_t dev;

	int i_scanned, i_passed;



	printk(KERN_INFO "md: Autodetecting RAID arrays.\n");

	i_scanned = 0;

	i_passed = 0;



	for (i = 0; i < dev_cnt; i++) {

		dev_t dev = detected_devices[i];

	printk(KERN_INFO "md: Autodetecting RAID arrays.\n");



	while (!list_empty(&all_detected_devices) && i_scanned < INT_MAX) {

		i_scanned++;

		node_detected_dev = list_entry(all_detected_devices.next,

					struct detected_devices_node, list);

		list_del(&node_detected_dev->list);

		dev = node_detected_dev->dev;

		kfree(node_detected_dev);

		rdev = md_import_device(dev,0, 90);

		if (IS_ERR(rdev))

			continue;
@@ -5799,8 +5820,11 @@ static void autostart_arrays(int part) 
			continue;

		}

		list_add(&rdev->same_set, &pending_raid_disks);

		i_passed++;

	}

	dev_cnt = 0;



	printk(KERN_INFO "md: Scanned %d and added %d devices.\n",

						i_scanned, i_passed);



	autorun_devices(part);

}