This patchset is a try to resolve the shared 'page cache' problem for
In order to track multiple mappings and indexes on one page, I
introduced a dax-rmap rb-tree to manage the relationship. A dax entry
will be associated more than once if is shared. At the second time we
associate this entry, we create this rb-tree and store its root in
page->private(not used in fsdax). Insert (->mapping, ->index) when
dax_associate_entry() and delete it when dax_disassociate_entry().
We can iterate the dax-rmap rb-tree before any other operations on
mappings of files. Such as memory-failure and rmap.
Same as before, I borrowed and made some changes on Goldwyn's patchsets.
These patches makes up for the lack of CoW mechanism in fsdax.
The rests are dax & reflink support for xfs.
(Rebased to 5.7-rc2)
Shiyang Ruan (8):
fs/dax: Introduce dax-rmap btree for reflink
mm: add dax-rmap for memory-failure and rmap
fs/dax: Introduce dax_copy_edges() for COW
fs/dax: copy data before write
fs/dax: replace mmap entry in case of CoW
fs/dax: dedup file range to use a compare function
fs/xfs: handle CoW for fsdax write() path
fs/xfs: support dedupe for fsdax
fs/dax.c | 343 +++++++++++++++++++++++++++++++++++++----
fs/ocfs2/file.c | 2 +-
fs/read_write.c | 11 +-
fs/xfs/xfs_bmap_util.c | 6 +-
fs/xfs/xfs_file.c | 10 +-
fs/xfs/xfs_iomap.c | 3 +-
fs/xfs/xfs_iops.c | 11 +-
fs/xfs/xfs_reflink.c | 79 ++++++----
include/linux/dax.h | 11 ++
include/linux/fs.h | 9 +-
mm/memory-failure.c | 63 ++++++--
mm/rmap.c | 54 +++++--
12 files changed, 498 insertions(+), 104 deletions(-)