[PATCH 0/6] dm/md sysfs dependency tree (rev.3)

[PATCH 0/6] dm/md sysfs dependency tree (rev.3)

[Jun'ichi Nomura]

Hello,

This is an updated version of dm/md sysfs dependency tree patch set.
For example, if dm-0 maps to sda, we'll have following symlinks;
   /sys/block/dm-0/slaves/sda --> /sys/block/sda
   /sys/block/sda/holders/dm-0 --> /sys/block/dm-0

Thanks for Alasdair, Neil and Greg for reviews and comments.
I think the patches get much better shape than before.
I'm happy to hear any other comments for these patches.

Patches included are:

  1. [PATCH 1/6] kobject_add_dir
     Adding kobject_add_dir() function which creates
     a subdirectory for a given kobject.

  2. [PATCH 2/6] add holders/slaves subdirectory to /sys/block
     Creating "slaves" and "holders" directories in /sys/block/<disk>,
     creating "holders" directory under /sys/block/<disk>/<partition>

  3. [PATCH 3/6] bd_claim_by_kobject
     Adding bd_claim_by_kobject() function which takes kobject as
     additional signature of holder device and creates sysfs symlinks
     between holder device and claimed device.
     bd_release_from_kobject() is a counter part of bd_claim_by_kobject.

  4. [PATCH 4/6] bd_claim_by_disk
     Variants which take gendisk instead of kobject
     and do kobject_{get,put}(&gendisk->kobj).

  5. [PATCH 5/6] md to use bd_claim_by_disk
     Use bd_claim_by_disk.

  6. [PATCH 6/6] dm to use bd_claim_by_disk
     Use bd_claim_by_disk.

Patches from 1 to 5 work both on 2.6.16-rc5 and 2.6.16-rc5-mm2.
I hope them to be included in mm if there's no problem.

Patch 6 depends on dm-table-store-md.patch in
http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/.
The dm-table-store-md.patch might theoretically require some
locking/release-ordering fixes in dm core which is under
investigation though it's separate issue.

Thanks,
-- 
Jun'ichi Nomura, NEC Solutions (America), Inc.

[PATCH 1/6] kobject_add_dir

[Jun'ichi Nomura]

[-- Attachment #1: Type: text/plain, Size: 199 bytes --]

This patch is part of dm/md sysfs dependency tree.

This adds kobject_add_dir() function which creates a subdirectory
for a given kobject.

Thanks,
-- 
Jun'ichi Nomura, NEC Solutions (America), Inc.

[-- Attachment #2: 01-kobject_add_dir.patch --]
[-- Type: text/x-patch, Size: 1753 bytes --]

Adding kobject_add_dir() function which creates a subdirectory
for a given kobject.

Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>

 include/linux/kobject.h |    2 ++
 lib/kobject.c           |   37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

--- linux-2.6.16-rc5.orig/include/linux/kobject.h	2006-02-27 00:09:35.000000000 -0500
+++ linux-2.6.16-rc5/include/linux/kobject.h	2006-03-02 14:26:26.000000000 -0500
@@ -80,6 +80,8 @@ extern void kobject_unregister(struct ko
 extern struct kobject * kobject_get(struct kobject *);
 extern void kobject_put(struct kobject *);
 
+extern struct kobject * kobject_add_dir(struct kobject *, const char *);
+
 extern char * kobject_get_path(struct kobject *, gfp_t);
 
 struct kobj_type {
--- linux-2.6.16-rc5.orig/lib/kobject.c	2006-02-27 00:09:35.000000000 -0500
+++ linux-2.6.16-rc5/lib/kobject.c	2006-03-02 14:26:26.000000000 -0500
@@ -379,6 +379,43 @@ void kobject_put(struct kobject * kobj)
 }
 
 
+static void dir_release(struct kobject *kobj)
+{
+	kfree(kobj);
+}
+
+static struct kobj_type dir_ktype = {
+	.release	= dir_release,
+	.sysfs_ops	= NULL,
+	.default_attrs	= NULL,
+};
+
+/**
+ *	kobject_add_dir - add sub directory of object.
+ *	@parent:	object in which a directory is created.
+ *	@name:	directory name.
+ *
+ *	Add a plain directory object as child of given object.
+ */
+struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
+{
+	struct kobject *k;
+
+	if (!parent)
+		return NULL;
+
+	k = kzalloc(sizeof(*k), GFP_KERNEL);
+	if (!k)
+		return NULL;
+
+	k->parent = parent;
+	k->ktype = &dir_ktype;
+	kobject_set_name(k, name);
+	kobject_register(k);
+
+	return k;
+}
+
 /**
  *	kset_init - initialize a kset for use
  *	@k:	kset 

[PATCH 2/6] add holders/slaves subdirectory to /sys/block

[Jun'ichi Nomura]

[-- Attachment #1: Type: text/plain, Size: 266 bytes --]

This patch is part of dm/md sysfs dependency tree.

With this patch, "slaves" and "holders" directories are
created in /sys/block/<disk> and
"holders" directory is created in /sys/block/<disk>/<partition>.

Thanks,
-- 
Jun'ichi Nomura, NEC Solutions (America), Inc.

[-- Attachment #2: 02-add_subdirs.patch --]
[-- Type: text/x-patch, Size: 2824 bytes --]

Creating "slaves" and "holders" directories in /sys/block/<disk> and
creating "holders" directory under /sys/block/<disk>/<partition>

Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>

 fs/partitions/check.c |   27 +++++++++++++++++++++++++++
 include/linux/genhd.h |    3 +++
 2 files changed, 30 insertions(+)

--- linux-2.6.16-rc5.orig/include/linux/genhd.h	2006-02-27 00:09:35.000000000 -0500
+++ linux-2.6.16-rc5/include/linux/genhd.h	2006-03-02 10:29:55.000000000 -0500
@@ -78,6 +78,7 @@ struct hd_struct {
 	sector_t start_sect;
 	sector_t nr_sects;
 	struct kobject kobj;
+	struct kobject *holder_dir;
 	unsigned ios[2], sectors[2];	/* READs and WRITEs */
 	int policy, partno;
 };
@@ -114,6 +115,8 @@ struct gendisk {
 	int number;			/* more of the same */
 	struct device *driverfs_dev;
 	struct kobject kobj;
+	struct kobject *holder_dir;
+	struct kobject *slave_dir;
 
 	struct timer_rand_state *random;
 	int policy;
--- linux-2.6.16-rc5.orig/fs/partitions/check.c	2006-02-27 00:09:35.000000000 -0500
+++ linux-2.6.16-rc5/fs/partitions/check.c	2006-03-02 10:29:55.000000000 -0500
@@ -297,6 +297,25 @@ struct kobj_type ktype_part = {
 	.sysfs_ops	= &part_sysfs_ops,
 };
 
+static inline void partition_sysfs_add_subdir(struct hd_struct *p)
+{
+	struct kobject *k;
+
+	k = kobject_get(&p->kobj);
+	p->holder_dir = kobject_add_dir(k, "holders");
+	kobject_put(k);
+}
+
+static inline void disk_sysfs_add_subdirs(struct gendisk *disk)
+{
+	struct kobject *k;
+
+	k = kobject_get(&disk->kobj);
+	disk->holder_dir = kobject_add_dir(k, "holders");
+	disk->slave_dir = kobject_add_dir(k, "slaves");
+	kobject_put(k);
+}
+
 void delete_partition(struct gendisk *disk, int part)
 {
 	struct hd_struct *p = disk->part[part-1];
@@ -310,6 +329,8 @@ void delete_partition(struct gendisk *di
 	p->ios[0] = p->ios[1] = 0;
 	p->sectors[0] = p->sectors[1] = 0;
 	devfs_remove("%s/part%d", disk->devfs_name, part);
+	if (p->holder_dir)
+		kobject_unregister(p->holder_dir);
 	kobject_unregister(&p->kobj);
 }
 
@@ -337,6 +358,7 @@ void add_partition(struct gendisk *disk,
 	p->kobj.parent = &disk->kobj;
 	p->kobj.ktype = &ktype_part;
 	kobject_register(&p->kobj);
+	partition_sysfs_add_subdir(p);
 	disk->part[part-1] = p;
 }
 
@@ -383,6 +405,7 @@ void register_disk(struct gendisk *disk)
 	if ((err = kobject_add(&disk->kobj)))
 		return;
 	disk_sysfs_symlinks(disk);
+ 	disk_sysfs_add_subdirs(disk);
 	kobject_uevent(&disk->kobj, KOBJ_ADD);
 
 	/* No minors to use for partitions */
@@ -483,6 +506,10 @@ void del_gendisk(struct gendisk *disk)
 
 	devfs_remove_disk(disk);
 
+	if (disk->holder_dir)
+		kobject_unregister(disk->holder_dir);
+	if (disk->holder_dir)
+		kobject_unregister(disk->slave_dir);
 	if (disk->driverfs_dev) {
 		char *disk_name = make_block_name(disk);
 		sysfs_remove_link(&disk->kobj, "device");

[PATCH 3/6] bd_claim_by_kobject

[Jun'ichi Nomura]

[-- Attachment #1: Type: text/plain, Size: 351 bytes --]

This patch is part of dm/md sysfs dependency tree.

This adds bd_claim_by_kobject() function which takes kobject as
additional signature of holder device and creates sysfs symlinks
between holder device and claimed device.
bd_release_from_kobject() is a counter part of bd_claim_by_kobject.

Thanks,
-- 
Jun'ichi Nomura, NEC Solutions (America), Inc.

[-- Attachment #2: 03-bd_claim_by_kobj.patch --]
[-- Type: text/x-patch, Size: 7290 bytes --]

Adding bd_claim_by_kobject() function which takes kobject as
additional signature of holder device and creates sysfs symlinks
between holder device and claimed device.
bd_release_from_kobject() is a counter part of bd_claim_by_kobject.

Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>

 fs/block_dev.c     |  196 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 include/linux/fs.h |    3
 2 files changed, 197 insertions(+), 2 deletions(-)

--- linux-2.6.16-rc5.orig/include/linux/fs.h	2006-02-27 00:09:35.000000000 -0500
+++ linux-2.6.16-rc5/include/linux/fs.h	2006-03-02 10:29:55.000000000 -0500
@@ -401,6 +401,7 @@ struct block_device {
 	struct list_head	bd_inodes;
 	void *			bd_holder;
 	int			bd_holders;
+	struct list_head	bd_holder_list;
 	struct block_device *	bd_contains;
 	unsigned		bd_block_size;
 	struct hd_struct *	bd_part;
@@ -1380,6 +1381,8 @@ extern int blkdev_get(struct block_devic
 extern int blkdev_put(struct block_device *);
 extern int bd_claim(struct block_device *, void *);
 extern void bd_release(struct block_device *);
+extern int bd_claim_by_kobject(struct block_device *, void *, struct kobject *);
+extern void bd_release_from_kobject(struct block_device *, struct kobject *);
 
 /* fs/char_dev.c */
 extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
--- linux-2.6.16-rc5.orig/fs/block_dev.c	2006-02-27 00:09:35.000000000 -0500
+++ linux-2.6.16-rc5/fs/block_dev.c	2006-03-02 10:29:55.000000000 -0500
@@ -269,6 +269,7 @@ static void init_once(void * foo, kmem_c
 		sema_init(&bdev->bd_mount_sem, 1);
 		INIT_LIST_HEAD(&bdev->bd_inodes);
 		INIT_LIST_HEAD(&bdev->bd_list);
+		INIT_LIST_HEAD(&bdev->bd_holder_list);
 		inode_init_once(&ei->vfs_inode);
 	}
 }
@@ -443,7 +444,179 @@ void bd_forget(struct inode *inode)
 	spin_unlock(&bdev_lock);
 }
 
-int bd_claim(struct block_device *bdev, void *holder)
+/*
+ * Functions for bd_claim_by_kobject / bd_release_from_kobject
+ *
+ *     If a kobject is passed to bd_claim_by_kobject() 
+ *     and the kobject has a parent directory,
+ *     following symlinks are created:
+ *        o from the kobject to the claimed bdev
+ *        o from "holders" directory of the bdev to the parent of the kobject
+ *     bd_release_from_kobject() removes these symlinks.
+ *
+ *     Example:
+ *        If /dev/dm-0 maps to /dev/sda, kobject corresponding to
+ *        /sys/block/dm-0/slaves is passed to bd_claim_by_kobject(), then:
+ *           /sys/block/dm-0/slaves/sda --> /sys/block/sda
+ *           /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
+ */
+
+static inline struct kobject * bdev_get_kobj(struct block_device *bdev)
+{
+	if (!bdev)
+		return NULL;
+	else if (bdev->bd_contains != bdev)
+		return kobject_get(&bdev->bd_part->kobj);
+	else
+		return kobject_get(&bdev->bd_disk->kobj);
+}
+
+static inline struct kobject * bdev_get_holder(struct block_device *bdev)
+{
+	if (!bdev)
+		return NULL;
+	else if (bdev->bd_contains != bdev)
+		return kobject_get(bdev->bd_part->holder_dir);
+	else
+		return kobject_get(bdev->bd_disk->holder_dir);
+}
+
+static inline void add_symlink(struct kobject *from, struct kobject *to)
+{
+	if (!from || !to)
+		return;
+	kobject_get(from);
+	kobject_get(to);
+	sysfs_create_link(from, to, kobject_name(to));
+}
+
+static inline void del_symlink(struct kobject *from, struct kobject *to)
+{
+	if (!from || !to)
+		return;
+	sysfs_remove_link(from, kobject_name(to));
+	kobject_put(from);
+	kobject_put(to);
+}
+
+static inline int bd_claim_grab_dirs(struct block_device *bdev,
+			struct kobject *holder,
+			struct kobject **sdir, struct kobject **sdev,
+			struct kobject **hdir, struct kobject **hdev)
+{
+	*sdir = kobject_get(holder);
+	if (!*sdir)
+		return 0;
+
+	*hdev = kobject_get((*sdir)->parent);
+	if (!*hdev)
+		goto fail_put_sdir;
+
+	*sdev = bdev_get_kobj(bdev);
+	if (!*sdev)
+		goto fail_put_hdev;
+
+	*hdir = bdev_get_holder(bdev);
+	if (!*hdir)
+		goto fail_put_sdev;
+
+	return 1;
+
+fail_put_sdev:
+	kobject_put(*sdev);
+fail_put_hdev:
+	kobject_put(*hdev);
+fail_put_sdir:
+	kobject_put(*sdir);
+
+	return 0;
+}
+
+static inline void bd_claim_release_dirs(
+			struct kobject *sdir, struct kobject *sdev,
+			struct kobject *hdir, struct kobject *hdev)
+{
+	kobject_put(hdir);
+	kobject_put(sdev);
+	kobject_put(hdev);
+	kobject_put(sdir);
+}
+
+static void link_bd_holder(struct block_device *bdev, struct kobject *holder)
+{
+	struct kobject *sdir, *sdev, *hdir, *hdev;
+
+	if (bd_claim_grab_dirs(bdev, holder, &sdir, &sdev, &hdir, &hdev)) {
+		add_symlink(sdir, sdev);
+		add_symlink(hdir, hdev);
+		bd_claim_release_dirs(sdir, sdev, hdir, hdev);
+	}
+
+	return;
+}
+
+static void unlink_bd_holder(struct block_device *bdev, struct kobject *holder)
+{
+	struct kobject *sdir, *sdev, *hdir, *hdev;
+
+	if (bd_claim_grab_dirs(bdev, holder, &sdir, &sdev, &hdir, &hdev)) {
+		del_symlink(sdir, sdev);
+		del_symlink(hdir, hdev);
+		bd_claim_release_dirs(sdir, sdev, hdir, hdev);
+	}
+}
+
+/* bd_holder_list is protected by bdev_lock */
+struct bd_holder {
+	struct list_head list;	/* chain of holders of the bdev */
+	int count;		/* references from the holder */
+	struct kobject *kobj;	/* holder kobject */
+};
+
+static int add_bd_holder(struct block_device *bdev, struct kobject *kobj)
+{
+        struct bd_holder *bo;
+
+	list_for_each_entry(bo, &bdev->bd_holder_list, list) {
+		if (bo->kobj == kobj) {
+			bo->count++;
+			return 0;
+		}
+	}
+
+	bo = kmalloc(sizeof(*bo), GFP_KERNEL);
+	if (!bo)
+		return -ENOMEM;
+
+	bo->count = 1;
+	bo->kobj = kobj;
+	list_add_tail(&bo->list, &bdev->bd_holder_list);
+	link_bd_holder(bdev, kobj);
+
+	return 0;
+}
+
+static int del_bd_holder(struct block_device *bdev, struct kobject *kobj)
+{
+	struct bd_holder *bo;
+
+	list_for_each_entry(bo, &bdev->bd_holder_list, list) {
+		if (bo->kobj == kobj) {
+			bo->count--;
+			BUG_ON(bo->count < 0);
+			if (!bo->count) {
+				unlink_bd_holder(bdev, kobj);
+				list_del(&bo->list);
+				kfree(bo);
+			}
+			break;
+		}
+	}
+
+	return 0;
+}
+
+int bd_claim_by_kobject(struct block_device *bdev, void *holder, struct kobject *kobj)
 {
 	int res;
 	spin_lock(&bdev_lock);
@@ -464,6 +637,9 @@ int bd_claim(struct block_device *bdev, 
 		res = 0;	 /* is a partition of an un-held device */
 
 	/* now impose change */
+	if (res == 0 && kobj)
+		res = add_bd_holder(bdev, kobj);
+
 	if (res==0) {
 		/* note that for a whole device bd_holders
 		 * will be incremented twice, and bd_holder will
@@ -478,11 +654,20 @@ int bd_claim(struct block_device *bdev, 
 	return res;
 }
 
+EXPORT_SYMBOL(bd_claim_by_kobject);
+
+int bd_claim(struct block_device *bdev, void *holder)
+{
+	return bd_claim_by_kobject(bdev, holder, NULL);
+}
+
 EXPORT_SYMBOL(bd_claim);
 
-void bd_release(struct block_device *bdev)
+void bd_release_from_kobject(struct block_device *bdev, struct kobject *kobj)
 {
 	spin_lock(&bdev_lock);
+	if (kobj)
+		del_bd_holder(bdev, kobj);
 	if (!--bdev->bd_contains->bd_holders)
 		bdev->bd_contains->bd_holder = NULL;
 	if (!--bdev->bd_holders)
@@ -490,6 +675,13 @@ void bd_release(struct block_device *bde
 	spin_unlock(&bdev_lock);
 }
 
+EXPORT_SYMBOL(bd_release_from_kobject);
+
+void bd_release(struct block_device *bdev)
+{
+	bd_release_from_kobject(bdev, NULL);
+}
+
 EXPORT_SYMBOL(bd_release);
 
 /*

[PATCH 4/6] bd_claim_by_disk

[Jun'ichi Nomura]

[-- Attachment #1: Type: text/plain, Size: 240 bytes --]

This patch is part of dm/md sysfs dependency tree.

This adds variants of bd_claim_by_kobject which takes gendisk instead
of kobject and do kobject_{get,put}(&gendisk->slave_dir).

Thanks,
-- 
Jun'ichi Nomura, NEC Solutions (America), Inc.

[-- Attachment #2: 04-bd_claim_by_disk.patch --]
[-- Type: text/x-patch, Size: 940 bytes --]

Variants of bd_claim_by_kobject which takes gendisk instead
of kobject and do kobject_{get,put}(&gendisk->slave_dir).

Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>

 include/linux/genhd.h |   13 +++++++++++++
 1 files changed, 13 insertions(+)

--- linux-2.6.16-rc5.orig/include/linux/genhd.h	2006-02-27 00:09:35.000000000 -0500
+++ linux-2.6.16-rc5/include/linux/genhd.h	2006-03-02 10:29:55.000000000 -0500
@@ -421,6 +424,19 @@ static inline struct block_device *bdget
 	return bdget(MKDEV(disk->major, disk->first_minor) + index);
 }
 
+static inline int bd_claim_by_disk(struct block_device *bdev,
+					void *holder, struct gendisk *disk)
+{
+	return bd_claim_by_kobject(bdev, holder, kobject_get(disk->slave_dir));
+}
+
+static inline void bd_release_from_disk(struct block_device *bdev,
+					struct gendisk *disk)
+{
+	bd_release_from_kobject(bdev, disk->slave_dir);
+	kobject_put(disk->slave_dir);
+}
+
 #endif
 
 #endif

[PATCH 5/6] md to use bd_claim_by_disk

[Jun'ichi Nomura]

[-- Attachment #1: Type: text/plain, Size: 366 bytes --]

This patch is part of dm/md sysfs dependency tree.

Following symlinks are created if md0 is built from sda and sdb
  /sys/block/md0/slaves/sda --> /sys/block/sda
  /sys/block/md0/slaves/sdb --> /sys/block/sdb
  /sys/block/sda/holders/md0 --> /sys/block/md0
  /sys/block/sdb/holders/md0 --> /sys/block/md0

Thanks,
-- 
Jun'ichi Nomura, NEC Solutions (America), Inc.

[-- Attachment #2: 05-md_deptree.patch --]
[-- Type: text/x-patch, Size: 1041 bytes --]

Use bd_claim_by_disk.

Following symlinks are created if md0 is built from sda and sdb
  /sys/block/md0/slaves/sda --> /sys/block/sda
  /sys/block/md0/slaves/sdb --> /sys/block/sdb
  /sys/block/sda/holders/md0 --> /sys/block/md0
  /sys/block/sdb/holders/md0 --> /sys/block/md0

Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>

 drivers/md/md.c |    2 ++
 1 files changed, 2 insertions(+)

--- linux-2.6.16-rc5.orig/drivers/md/md.c	2006-02-27 00:09:35.000000000 -0500
+++ linux-2.6.16-rc5/drivers/md/md.c	2006-03-02 14:57:05.000000000 -0500
@@ -1298,6 +1298,7 @@ static int bind_rdev_to_array(mdk_rdev_t
 	else
 		ko = &rdev->bdev->bd_disk->kobj;
 	sysfs_create_link(&rdev->kobj, ko, "block");
+	bd_claim_by_disk(rdev->bdev, rdev, mddev->gendisk);
 	return 0;
 }
 
@@ -1308,6 +1309,7 @@ static void unbind_rdev_from_array(mdk_r
 		MD_BUG();
 		return;
 	}
+	bd_release_from_disk(rdev->bdev, rdev->mddev->gendisk);
 	list_del_init(&rdev->same_set);
 	printk(KERN_INFO "md: unbind<%s>\n", bdevname(rdev->bdev,b));
 	rdev->mddev = NULL;

[PATCH 6/6] dm to use bd_claim_by_disk

[Jun'ichi Nomura]

[-- Attachment #1: Type: text/plain, Size: 383 bytes --]

This patch is part of dm/md sysfs dependency tree.

Following symlinks are created if dm-0 maps to sda:
  /sys/block/dm-0/slaves/sda --> /sys/block/sda
  /sys/block/sda/holders/dm-0 --> /sys/block/dm-0

This patch depends on dm-table-store-md.patch in
http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/

Thanks,
-- 
Jun'ichi Nomura, NEC Solutions (America), Inc.

[-- Attachment #2: 06-dm_deptree.patch --]
[-- Type: text/x-patch, Size: 2904 bytes --]

Use bd_claim_by_disk.

Following symlinks are created if dm-0 maps to sda:
  /sys/block/dm-0/slaves/sda --> /sys/block/sda
  /sys/block/sda/holders/dm-0 --> /sys/block/dm-0

This patch depends on dm-table-store-md.patch in
http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/

Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>

 drivers/md/dm-table.c |   20 ++++++++++----------
 1 files changed, 10 insertions(+), 10 deletions(-)

--- linux-2.6.16-rc5.orig/drivers/md/dm-table.c	2006-03-02 14:55:14.000000000 -0500
+++ linux-2.6.16-rc5/drivers/md/dm-table.c	2006-03-02 14:57:01.000000000 -0500
@@ -348,7 +348,7 @@ static struct dm_dev *find_device(struct
 /*
  * Open a device so we can use it as a map destination.
  */
-static int open_dev(struct dm_dev *d, dev_t dev)
+static int open_dev(struct dm_dev *d, dev_t dev, struct gendisk *holder)
 {
 	static char *_claim_ptr = "I belong to device-mapper";
 	struct block_device *bdev;
@@ -361,7 +361,7 @@ static int open_dev(struct dm_dev *d, de
 	bdev = open_by_devnum(dev, d->mode);
 	if (IS_ERR(bdev))
 		return PTR_ERR(bdev);
-	r = bd_claim(bdev, _claim_ptr);
+	r = bd_claim_by_disk(bdev, _claim_ptr, holder);
 	if (r)
 		blkdev_put(bdev);
 	else
@@ -372,12 +372,12 @@ static int open_dev(struct dm_dev *d, de
 /*
  * Close a device that we've been using.
  */
-static void close_dev(struct dm_dev *d)
+static void close_dev(struct dm_dev *d, struct gendisk *holder)
 {
 	if (!d->bdev)
 		return;
 
-	bd_release(d->bdev);
+	bd_release_from_disk(d->bdev, holder);
 	blkdev_put(d->bdev);
 	d->bdev = NULL;
 }
@@ -398,7 +398,7 @@ static int check_device_area(struct dm_d
  * careful to leave things as they were if we fail to reopen the
  * device.
  */
-static int upgrade_mode(struct dm_dev *dd, int new_mode)
+static int upgrade_mode(struct dm_dev *dd, int new_mode, struct gendisk *holder)
 {
 	int r;
 	struct dm_dev dd_copy;
@@ -408,9 +408,9 @@ static int upgrade_mode(struct dm_dev *d
 
 	dd->mode |= new_mode;
 	dd->bdev = NULL;
-	r = open_dev(dd, dev);
+	r = open_dev(dd, dev, holder);
 	if (!r)
-		close_dev(&dd_copy);
+		close_dev(&dd_copy, holder);
 	else
 		*dd = dd_copy;
 
@@ -453,7 +453,7 @@ static int __table_get_device(struct dm_
 		dd->mode = mode;
 		dd->bdev = NULL;
 
-		if ((r = open_dev(dd, dev))) {
+		if ((r = open_dev(dd, dev, dm_disk(t->md)))) {
 			kfree(dd);
 			return r;
 		}
@@ -464,7 +464,7 @@ static int __table_get_device(struct dm_
 		list_add(&dd->list, &t->devices);
 
 	} else if (dd->mode != (mode | dd->mode)) {
-		r = upgrade_mode(dd, mode);
+		r = upgrade_mode(dd, mode, dm_disk(t->md));
 		if (r)
 			return r;
 	}
@@ -539,7 +539,7 @@ int dm_get_device(struct dm_target *ti, 
 void dm_put_device(struct dm_target *ti, struct dm_dev *dd)
 {
 	if (atomic_dec_and_test(&dd->count)) {
-		close_dev(dd);
+		close_dev(dd, dm_disk(ti->table->md));
 		list_del(&dd->list);
 		kfree(dd);
 	}

Re: [PATCH 6/6] dm to use bd_claim_by_disk

[Alasdair G Kergon]

On Fri, Mar 03, 2006 at 07:58:32PM -0500, Jun'ichi Nomura wrote:
> This patch is part of dm/md sysfs dependency tree.
 
> +static int open_dev(struct dm_dev *d, dev_t dev, struct gendisk *holder)
> +static int upgrade_mode(struct dm_dev *dd, int new_mode, struct gendisk *holder)
> +static void close_dev(struct dm_dev *d, struct gendisk *holder)

Please pass the dm structure, struct mapped_device, around between dm functions
internally where you can, instead of struct gendisk.  (Every time the new 
parameter is passed it's wrapped with dm_disk(), so move the dm_disk() inside.)

Alasdair
-- 
agk@redhat.com

Re: [PATCH 6/6] dm to use bd_claim_by_disk

[Jun'ichi Nomura]

[-- Attachment #1: Type: text/plain, Size: 697 bytes --]

Hi Alasdair,

Alasdair G Kergon wrote:
 >>+static int open_dev(struct dm_dev *d, dev_t dev, struct gendisk *holder)
 >>+static int upgrade_mode(struct dm_dev *dd, int new_mode, struct gendisk *holder)
 >>+static void close_dev(struct dm_dev *d, struct gendisk *holder)
 >
 > Please pass the dm structure, struct mapped_device, around between dm functions
 > internally where you can, instead of struct gendisk.  (Every time the new
 > parameter is passed it's wrapped with dm_disk(), so move the dm_disk() inside.)

Thank you for the comment. I changed them and updated the patch.
Could you check whether there is any other wrong thing?

Thanks,
-- 
Jun'ichi Nomura, NEC Solutions (America), Inc.

[-- Attachment #2: 06-dm_deptree-2.patch --]
[-- Type: text/x-patch, Size: 2886 bytes --]

Use bd_claim_by_disk.

Following symlinks are created if dm-0 maps to sda:
  /sys/block/dm-0/slaves/sda --> /sys/block/sda
  /sys/block/sda/holders/dm-0 --> /sys/block/dm-0

This patch depends on dm-table-store-md.patch in
http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/

Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>

 drivers/md/dm-table.c |   20 ++++++++++----------
 1 files changed, 10 insertions(+), 10 deletions(-)


--- linux-2.6.16-rc5.orig/drivers/md/dm-table.c	2006-03-02 14:55:14.000000000 -0500
+++ linux-2.6.16-rc5/drivers/md/dm-table.c	2006-03-06 11:00:23.000000000 -0500
@@ -348,7 +348,7 @@ static struct dm_dev *find_device(struct
 /*
  * Open a device so we can use it as a map destination.
  */
-static int open_dev(struct dm_dev *d, dev_t dev)
+static int open_dev(struct dm_dev *d, dev_t dev, struct mapped_device *md)
 {
 	static char *_claim_ptr = "I belong to device-mapper";
 	struct block_device *bdev;
@@ -361,7 +361,7 @@ static int open_dev(struct dm_dev *d, de
 	bdev = open_by_devnum(dev, d->mode);
 	if (IS_ERR(bdev))
 		return PTR_ERR(bdev);
-	r = bd_claim(bdev, _claim_ptr);
+	r = bd_claim_by_disk(bdev, _claim_ptr, dm_disk(md));
 	if (r)
 		blkdev_put(bdev);
 	else
@@ -372,12 +372,12 @@ static int open_dev(struct dm_dev *d, de
 /*
  * Close a device that we've been using.
  */
-static void close_dev(struct dm_dev *d)
+static void close_dev(struct dm_dev *d, struct mapped_device *md)
 {
 	if (!d->bdev)
 		return;
 
-	bd_release(d->bdev);
+	bd_release_from_disk(d->bdev, dm_disk(md));
 	blkdev_put(d->bdev);
 	d->bdev = NULL;
 }
@@ -398,7 +398,7 @@ static int check_device_area(struct dm_d
  * careful to leave things as they were if we fail to reopen the
  * device.
  */
-static int upgrade_mode(struct dm_dev *dd, int new_mode)
+static int upgrade_mode(struct dm_dev *dd, int new_mode, struct mapped_device *md)
 {
 	int r;
 	struct dm_dev dd_copy;
@@ -408,9 +408,9 @@ static int upgrade_mode(struct dm_dev *d
 
 	dd->mode |= new_mode;
 	dd->bdev = NULL;
-	r = open_dev(dd, dev);
+	r = open_dev(dd, dev, md);
 	if (!r)
-		close_dev(&dd_copy);
+		close_dev(&dd_copy, md);
 	else
 		*dd = dd_copy;
 
@@ -453,7 +453,7 @@ static int __table_get_device(struct dm_
 		dd->mode = mode;
 		dd->bdev = NULL;
 
-		if ((r = open_dev(dd, dev))) {
+		if ((r = open_dev(dd, dev, t->md))) {
 			kfree(dd);
 			return r;
 		}
@@ -464,7 +464,7 @@ static int __table_get_device(struct dm_
 		list_add(&dd->list, &t->devices);
 
 	} else if (dd->mode != (mode | dd->mode)) {
-		r = upgrade_mode(dd, mode);
+		r = upgrade_mode(dd, mode, t->md);
 		if (r)
 			return r;
 	}
@@ -539,7 +539,7 @@ int dm_get_device(struct dm_target *ti, 
 void dm_put_device(struct dm_target *ti, struct dm_dev *dd)
 {
 	if (atomic_dec_and_test(&dd->count)) {
-		close_dev(dd);
+		close_dev(dd, ti->table->md);
 		list_del(&dd->list);
 		kfree(dd);
 	}