From: "Jun'ichi Nomura" <j-nomura@ce.jp.nec.com>
To: Neil Brown <neilb@suse.de>, Alasdair Kergon <agk@redhat.com>,
Lars Marowsky-Bree <lmb@suse.de>, Greg KH <gregkh@suse.de>
Cc: linux-kernel@vger.kernel.org,
device-mapper development <dm-devel@redhat.com>
Subject: [PATCH 0/3] sysfs representation of stacked devices (dm/md) (rev.2)
Date: Wed, 22 Feb 2006 11:06:24 -0500 [thread overview]
Message-ID: <43FC8C00.5020600@ce.jp.nec.com> (raw)
Hello,
This is a revised set of pathces which provides common
representation of dependencies between stacked devices (dm and md)
in sysfs.
Variants of bd_claim/bd_release are added to accept a kobject
and create symlinks between the claimed bdev and the holder.
dm/md will give a child of its gendisk kobject to bd_claim.
For example, if dm-0 maps to sda, we have the following symlinks;
/sys/block/dm-0/slaves/sda --> /sys/block/sda
/sys/block/sda/holders/dm-0 --> /sys/block/dm-0
Comments are welcome.
A few points I would appreciate comments/reviews from maintainers:
About sysfs
- I confirmed sysfs_remove_symlink() and kobject_del() don't
allocate memory in 2.6.15 and it seems true on the git head.
I would like to make sure it's true in future versions of kernel
because they are called during device-mapper's table swapping
where I/O to free memory could deadlock on the dm device.
What is the recommended way to do that?
Or can I just expect these functions will not allocate memory
in future versions of kernel?
About dm
- To get a reference to mapped_device, table_load() do
dm_get() before populating table. It will dm_put() when
the table is being discarded or the table is being activated.
About md
- Rather than carrying mddev pointer around, bd_claim is now
made twice. First is not changed at lock_rdev().
The second is at bind_rdev_to_array() where kobject is passed
and symlinks are created.
--
Jun'ichi Nomura, NEC Solutions (America), Inc.
next reply other threads:[~2006-02-22 16:05 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-22 16:06 Jun'ichi Nomura [this message]
2006-02-22 16:13 ` [PATCH 1/3] sysfs representation of stacked devices (common) (rev.2) Jun'ichi Nomura
2006-02-22 18:48 ` Greg KH
2006-02-22 22:22 ` Jun'ichi Nomura
2006-02-22 22:28 ` Greg KH
2006-02-23 19:15 ` Jun'ichi Nomura
2006-02-24 3:40 ` Greg KH
2006-02-27 16:09 ` Jun'ichi Nomura
2006-02-22 16:13 ` [PATCH 2/3] sysfs representation of stacked devices (dm) (rev.2) Jun'ichi Nomura
2006-02-22 16:34 ` Alasdair G Kergon
2006-02-22 17:13 ` Jun'ichi Nomura
2006-02-22 18:13 ` Alasdair G Kergon
2006-02-22 19:32 ` Jun'ichi Nomura
2006-02-22 16:13 ` [PATCH 3/3] sysfs representation of stacked devices (md) (rev.2) Jun'ichi Nomura
2006-02-22 18:47 ` [PATCH 0/3] sysfs representation of stacked devices (dm/md) (rev.2) Greg KH
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