On Tue, Jan 26, 2016 at 10:58:44AM -0500, Chuck Lever wrote:
> It is not going to be like the well-worn paradigm that
> involves a page cache on the storage target backed by
> slow I/O operations. The protocol layers on storage
> targets need a way to discover memory addresses of
> persistent memory that will be used as source/sink
> buffers for RDMA operations.
>
> And making data durable after a write is going to need
> some thought. So I believe some new plumbing will be
> necessary.
Haven't we already solve this for the pNFS file driver that XFS
implements? i.e. these export operations:
int (*get_uuid)(struct super_block *sb, u8 *buf, u32 *len, u64 *offset);
int (*map_blocks)(struct inode *inode, loff_t offset,
u64 len, struct iomap *iomap,
bool write, u32 *device_generation);
int (*commit_blocks)(struct inode *inode, struct iomap *iomaps,
int nr_iomaps, struct iattr *iattr);
so mapping/allocation of file offset to sector mappings, which can
then trivially be used to grab the memory address through the bdev
->direct_access method, yes?
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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