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由 Laurent Vivier 提交于
Permit the use of partitions with network block devices (NBD). A new parameter is introduced to define how many partition we want to be able to manage per network block device. This parameter is "max_part". For instance, to manage 63 partitions / loop device, we will do: [on the server side] # nbd-server 1234 /dev/sdb [on the client side] # modprobe nbd max_part=63 # ls -l /dev/nbd* brw-rw---- 1 root disk 43, 0 2008-03-25 11:14 /dev/nbd0 brw-rw---- 1 root disk 43, 64 2008-03-25 11:11 /dev/nbd1 brw-rw---- 1 root disk 43, 640 2008-03-25 11:11 /dev/nbd10 brw-rw---- 1 root disk 43, 704 2008-03-25 11:11 /dev/nbd11 brw-rw---- 1 root disk 43, 768 2008-03-25 11:11 /dev/nbd12 brw-rw---- 1 root disk 43, 832 2008-03-25 11:11 /dev/nbd13 brw-rw---- 1 root disk 43, 896 2008-03-25 11:11 /dev/nbd14 brw-rw---- 1 root disk 43, 960 2008-03-25 11:11 /dev/nbd15 brw-rw---- 1 root disk 43, 128 2008-03-25 11:11 /dev/nbd2 brw-rw---- 1 root disk 43, 192 2008-03-25 11:11 /dev/nbd3 brw-rw---- 1 root disk 43, 256 2008-03-25 11:11 /dev/nbd4 brw-rw---- 1 root disk 43, 320 2008-03-25 11:11 /dev/nbd5 brw-rw---- 1 root disk 43, 384 2008-03-25 11:11 /dev/nbd6 brw-rw---- 1 root disk 43, 448 2008-03-25 11:11 /dev/nbd7 brw-rw---- 1 root disk 43, 512 2008-03-25 11:11 /dev/nbd8 brw-rw---- 1 root disk 43, 576 2008-03-25 11:11 /dev/nbd9 # nbd-client localhost 1234 /dev/nbd0 Negotiation: ..size = 80418240KB bs=1024, sz=80418240 -------NOTE, RFC: partition table is not automatically read. The driver sets bdev->bd_invalidated to 1 to force the read of the partition table of the device, but this is done only on an open of the device. So we have to do a "touch /dev/nbdX" or something like that. It can't be done from the nbd-client or nbd driver because at this level we can't ask to read the partition table and to serve the request at the same time (-> deadlock) If someone has a better idea, I'm open to any suggestion. -------NOTE, RFC # fdisk -l /dev/nbd0 Disk /dev/nbd0: 82.3 GB, 82348277760 bytes 255 heads, 63 sectors/track, 10011 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/nbd0p1 * 1 9965 80043831 83 Linux /dev/nbd0p2 9966 10011 369495 5 Extended /dev/nbd0p5 9966 10011 369463+ 82 Linux swap / Solaris # ls -l /dev/nbd0* brw-rw---- 1 root disk 43, 0 2008-03-25 11:16 /dev/nbd0 brw-rw---- 1 root disk 43, 1 2008-03-25 11:16 /dev/nbd0p1 brw-rw---- 1 root disk 43, 2 2008-03-25 11:16 /dev/nbd0p2 brw-rw---- 1 root disk 43, 5 2008-03-25 11:16 /dev/nbd0p5 # mount /dev/nbd0p1 /mnt # ls /mnt bin dev initrd lost+found opt sbin sys var boot etc initrd.img media proc selinux tmp vmlinuz cdrom home lib mnt root srv usr # umount /mnt # nbd-client -d /dev/nbd0 # ls -l /dev/nbd0* brw-rw---- 1 root disk 43, 0 2008-03-25 11:16 /dev/nbd0 -------NOTE On "nbd-client -d", we can do an iocl(BLKRRPART) to update partition table: as the size of the device is 0, we don't have to serve the partition manager request (-> no deadlock). -------NOTE Signed-off-by: NPaul Clements <paul.clements@steeleye.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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