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Commit 6d7ff738 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
Browse files

[PATCH] md: support adding new devices to md arrays via sysfs 



Writing major:minor to md/new_dev will bind that device to the array.

Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Acked-by: default avatarGreg KH <greg@kroah.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 83303b61

Documentation/md.txt

+8 −0
Original line number Original line Diff line number Diff line
@@ -200,6 +200,14 @@ All md devices contain: 
     This can be written only while the array is being assembled, not

     This can be written only while the array is being assembled, not

     after it is started.

     after it is started.





   new_dev

     This file can be written but not read.  The value written should

     be a block device number as major:minor.  e.g. 8:0

     This will cause that device to be attached to the array, if it is

     available.  It will then appear at md/dev-XXX (depending on the

     name of the device) and further configuration is then possible.





As component devices are added to an md array, they appear in the 'md'

As component devices are added to an md array, they appear in the 'md'

directory as new directories named

directory as new directories named

      dev-XXX

      dev-XXX

drivers/md/md.c

+60 −0
Original line number Original line Diff line number Diff line
@@ -1987,6 +1987,65 @@ chunk_size_store(mddev_t *mddev, const char *buf, size_t len) 
static struct md_sysfs_entry md_chunk_size =

static struct md_sysfs_entry md_chunk_size =

__ATTR(chunk_size, 0644, chunk_size_show, chunk_size_store);

__ATTR(chunk_size, 0644, chunk_size_show, chunk_size_store);





static ssize_t

null_show(mddev_t *mddev, char *page)

{

	return -EINVAL;

}



static ssize_t

new_dev_store(mddev_t *mddev, const char *buf, size_t len)

{

	/* buf must be %d:%d\n? giving major and minor numbers */

	/* The new device is added to the array.

	 * If the array has a persistent superblock, we read the

	 * superblock to initialise info and check validity.

	 * Otherwise, only checking done is that in bind_rdev_to_array,

	 * which mainly checks size.

	 */

	char *e;

	int major = simple_strtoul(buf, &e, 10);

	int minor;

	dev_t dev;

	mdk_rdev_t *rdev;

	int err;



	if (!*buf || *e != ':' || !e[1] || e[1] == '\n')

		return -EINVAL;

	minor = simple_strtoul(e+1, &e, 10);

	if (*e && *e != '\n')

		return -EINVAL;

	dev = MKDEV(major, minor);

	if (major != MAJOR(dev) ||

	    minor != MINOR(dev))

		return -EOVERFLOW;





	if (mddev->persistent) {

		rdev = md_import_device(dev, mddev->major_version,

					mddev->minor_version);

		if (!IS_ERR(rdev) && !list_empty(&mddev->disks)) {

			mdk_rdev_t *rdev0 = list_entry(mddev->disks.next,

						       mdk_rdev_t, same_set);

			err = super_types[mddev->major_version]

				.load_super(rdev, rdev0, mddev->minor_version);

			if (err < 0)

				goto out;

		}

	} else

		rdev = md_import_device(dev, -1, -1);



	if (IS_ERR(rdev))

		return PTR_ERR(rdev);

	err = bind_rdev_to_array(rdev, mddev);

 out:

	if (err)

		export_rdev(rdev);

	return err ? err : len;

}



static struct md_sysfs_entry md_new_device =

__ATTR(new_dev, 0200, null_show, new_dev_store);





static ssize_t

static ssize_t

size_show(mddev_t *mddev, char *page)

size_show(mddev_t *mddev, char *page)
@@ -2144,6 +2203,7 @@ static struct attribute *md_default_attrs[] = { 
	&md_chunk_size.attr,

	&md_chunk_size.attr,

	&md_size.attr,

	&md_size.attr,

	&md_metadata.attr,

	&md_metadata.attr,

	&md_new_device.attr,

	NULL,

	NULL,

};

};