On Thu, Aug 21, 2014 at 9:09 AM, Christoph Hellwig <hch@xxxxxx> wrote: > 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@xxxxxx> > --- > fs/nfs/blocklayout/Makefile | 3 +- > fs/nfs/blocklayout/blocklayout.c | 258 +++------- > fs/nfs/blocklayout/blocklayout.h | 112 +---- > fs/nfs/blocklayout/blocklayoutdev.c | 35 +- > fs/nfs/blocklayout/extent_tree.c | 545 ++++++++++++++++++++++ > fs/nfs/blocklayout/extents.c | 908 ------------------------------------ > 6 files changed, 649 insertions(+), 1212 deletions(-) > create mode 100644 fs/nfs/blocklayout/extent_tree.c > delete mode 100644 fs/nfs/blocklayout/extents.c > Holding due to dependencies on unapplied patches in the series. -- Trond Myklebust Linux NFS client maintainer, PrimaryData trond.myklebust@xxxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
