Re: [PATCH 8/8] rbd: introduce rados block device (rbd), based onlibceph

[Sage Weil]

On Fri, 13 Aug 2010, Randy Dunlap wrote:
> On Fri, 13 Aug 2010 10:40:40 -0700 Sage Weil wrote:
> 
> > From: Yehuda Sadeh <yehuda@xxxxxxxxxxxxxxx>
> > 
> > The rados block device (rbd), based on osdblk, creates a block device
> > that is backed by objects stored in the Ceph distributed object storage
> > cluster.  Each device consists of a single metadata object and data
> > striped over many data objects.
> > 
> > The rbd driver supports read-only snapshots.
> > 
> > Signed-off-by: Yehuda Sadeh <yehuda@xxxxxxxxxxxxxxx>
> > Signed-off-by: Sage Weil <sage@xxxxxxxxxxxx>
> > ---
> >  MAINTAINERS               |    9 +
> >  drivers/block/Kconfig     |   13 +
> >  drivers/block/Makefile    |    1 +
> >  drivers/block/rbd.c       | 1844 +++++++++++++++++++++++++++++++++++++++++++++
> >  drivers/block/rbd_types.h |   73 ++
> >  5 files changed, 1940 insertions(+), 0 deletions(-)
> >  create mode 100644 drivers/block/rbd.c
> >  create mode 100644 drivers/block/rbd_types.h
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 5102922..cb34b1b 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -4694,6 +4694,15 @@ F:	fs/qnx4/
> >  F:	include/linux/qnx4_fs.h
> >  F:	include/linux/qnxtypes.h
> >  
> > +RADOS BLOCK DEVICE (RBD)
> > +F:	include/linux/qnxtypes.h
> > +M:	Yehuda Sadeh <yehuda@xxxxxxxxxxxxxxx>
> > +M:	Sage Weil <sage@xxxxxxxxxxxx>
> > +M:	ceph-devel@xxxxxxxxxxxxxxx
> > +S:	Supported
> > +F:	drivers/block/rbd.c
> > +F:	drivers/block/rbd_types.h
> > +
> >  RADEON FRAMEBUFFER DISPLAY DRIVER
> >  M:	Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> >  L:	linux-fbdev@xxxxxxxxxxxxxxx
> > diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
> > index de27768..708104b 100644
> > --- a/drivers/block/Kconfig
> > +++ b/drivers/block/Kconfig
> > @@ -488,4 +488,17 @@ config BLK_DEV_HD
> >  
> >  	  If unsure, say N.
> >  
> > +config BLK_DEV_RBD
> > +	tristate "Rados block device (RBD)"
> > +	select CEPH_LIB
> > +	default n
> > +	help
> > +	  Say Y here if you want include the Rados block device, which stripes
> > +	  a block device over objects stored in the Ceph distributed object
> > +	  store.
> > +
> > +	  More information at http://ceph.newdream.net/.
> > +
> > +	  If unsure, say N.
> > +
> >  endif # BLK_DEV
> 
> In linux-next of 20100813, I get:
> 
> net/built-in.o: In function `read_partial_message_section':
> messenger.c:(.text+0x6598b): undefined reference to `crc32c'
> net/built-in.o: In function `read_partial_message_bio':
> messenger.c:(.text+0x65a57): undefined reference to `crc32c'
> net/built-in.o: In function `write_partial_msg_pages':
> messenger.c:(.text+0x65e22): undefined reference to `crc32c'
> net/built-in.o: In function `prepare_write_message':
> messenger.c:(.text+0x66219): undefined reference to `crc32c'
> messenger.c:(.text+0x66240): undefined reference to `crc32c'
> net/built-in.o:messenger.c:(.text+0x66264): more undefined references to `crc32c' follow
> 
> when CONFIG_INET is not enabled.  It looks like BLK_DEV_RBD needs to depend on
> INET and possibly on BLOCK (I sent a patch for depends on BLOCK on 2010-aug-04
> due to other build errors).

I see the problem: BLK_DEV_RBD and CEPH_FS both have 'select CEPH_LIB' and 
CEPH_LIB depends on INET and selects LIBCRC32C, but kconfig doesn't 
propagate those backward dependencies for you.  It looks like CEPH_FS and 
BLK_DEV_RBD should then depend on/select CEPH_LIB _and_ its dependencies.  
Patching that (and the BLOCK dependency) up now...

Unless there is a better way to do it?

Thanks!
sage


diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 708104b..4a6e1b7 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -490,7 +490,10 @@ config BLK_DEV_HD
 
 config BLK_DEV_RBD
 	tristate "Rados block device (RBD)"
+	depends on INET && EXPERIMENTAL && BLOCK
 	select CEPH_LIB
+	select LIBCRC32C
+	select CRYPTO_AES
 	default n
 	help
 	  Say Y here if you want include the Rados block device, which stripes
diff --git a/fs/ceph/Kconfig b/fs/ceph/Kconfig
index 89f9718..73a7b31 100644
--- a/fs/ceph/Kconfig
+++ b/fs/ceph/Kconfig
@@ -1,9 +1,9 @@
 config CEPH_FS
         tristate "Ceph distributed file system (EXPERIMENTAL)"
 	depends on INET && EXPERIMENTAL
+	select CEPH_LIB
 	select LIBCRC32C
 	select CRYPTO_AES
-	select CEPH_LIB
 	default n
 	help
 	  Choose Y or M here to include support for mounting the
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