This patches moves parsing of the GETDEVICEINFO XDR to kernel space, as well
as the management of complex devices. The reason for that is we might have
multiple outstanding complex devices after a NOTIFY_DEVICEID4_CHANGE, which
device mapper or md can't handle as they claim devices exclusively.
But as is turns out simple striping / concatenation is fairly trivial to
implement anyway, so we make our life simpler by reducing the reliance
on blkmapd. For now we still use blkmapd by feeding it synthetic SIMPLE
device XDR to translate device signatures to device numbers, but in the
long runs I have plans to eliminate it entirely.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Create a file to house all the rpc_pipefs boilerplate code instead of
sprinkling it over a few files.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Currently the block layout driver tracks extents in three separate
data structures:
- the two list of pnfs_block_extent structures returned by the server
- the list of sectors that were in invalid state but have been written to
- a list of pnfs_block_short_extent structures for LAYOUTCOMMIT
All of these share the property that they are not only highly inefficient
data structures, but also that operations on them are even more inefficient
than nessecary.
In addition there are various implementation defects like:
- using an int to track sectors, causing corruption for large offsets
- incorrect normalization of page or block granularity ranges
- insufficient error handling
- incorrect synchronization as extents can be modified while they are in
use
This patch replace all three data with a single unified rbtree structure
tracking all extents, as well as their in-memory state, although we still
need to instance for read-only and read-write extent due to the arcane
client side COW feature in the block layouts spec.
To fix the problem of extent possibly being modified while in use we make
sure to return a copy of the extent for use in the write path - the
extent can only be invalidated by a layout recall or return which has
to wait until the I/O operations finished due to refcounts on the layout
segment.
The new extent tree work similar to the schemes used by block based
filesystems like XFS or ext4.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Christoph Hellwig