: Expand xvd to support > 16 devices
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Patches in v1 No applies recorded yet
| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 1/4 | : Fix blkfront to accept expanded devicesdrivers/ drivers/ | +47 | 0 replies | |
| 2/4 | : Blktap backend fixesdrivers/ | +8 | 0 replies | |
| 3/4 | : Extend blktap userland busid to 32-bitstools/ tools/ | +2 | 0 replies | |
| 4/4 | : python blkdev_name_to_number fixestools/ tools/ tools/ +1 more | +29 | 2 replies |
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Cover letter [PATCH 0/4]: Expand xvd to support > 16 devices
All,
Current blktap and blkfront are limited to 16 xvd devices (xvda -> xvdp).
This is enforced in the userland dom0 tools, but is also hard-coded into the blkfront kernel code (even though modern dev_t can hold many more than 256 minors). Based on the discussion that we had here:
http://lists.xensource.com/archives/html/xen-devel/2008-05/msg00128.html
I ended up implementing Ian Jackson's suggestion here:
http://lists.xensource.com/archives/html/xen-devel/2008-05/msg00231.html
Basically, I left the old format alone, but added a new format that looks like:
1 << 28 | disk << 8 | partition xvd, disks or partitions 16 onwards
This format is used for any disks xvdq onward. Note that blktap has a hardcoded limit of 100 devices that I did not change with this patch series; if that ends up being a problem, then that's just a simple #define to change.
I did not expand the number of partitions available (it's still 15), although there is space in the allocation to do that if someone wishes. More details are in each individual patch.
Note that I developed this against RHEL-5 kernels and ported it over to xen-unstable, and only compile tested it there.
Chris Lalancette