On Mon 08-02-21 01:09:17, Shiyang Ruan wrote: > This patchset is attempt to add CoW support for fsdax, and take XFS, > which has both reflink and fsdax feature, as an example. > > One of the key mechanism need to be implemented in fsdax is CoW. Copy > the data from srcmap before we actually write data to the destance > iomap. And we just copy range in which data won't be changed. > > Another mechanism is range comparison . In page cache case, readpage() > is used to load data on disk to page cache in order to be able to > compare data. In fsdax case, readpage() does not work. So, we need > another compare data with direct access support. > > With the two mechanism implemented in fsdax, we are able to make reflink > and fsdax work together in XFS. > > Some of the patches are picked up from Goldwyn's patchset. I made some > changes to adapt to this patchset. How do you deal with HWPoison code trying to reverse-map struct page back to inode-offset pair? This also needs to be fixed for reflink to work with DAX. Honza > > (Rebased on v5.10) > == > > Shiyang Ruan (7): > fsdax: Output address in dax_iomap_pfn() and rename it > fsdax: Introduce dax_copy_edges() for CoW > fsdax: Copy data before write > fsdax: Replace mmap entry in case of CoW > fsdax: Dedup file range to use a compare function > fs/xfs: Handle CoW for fsdax write() path > fs/xfs: Add dedupe support for fsdax > > fs/btrfs/reflink.c | 3 +- > fs/dax.c | 188 ++++++++++++++++++++++++++++++++++++++--- > fs/ocfs2/file.c | 2 +- > fs/remap_range.c | 14 +-- > fs/xfs/xfs_bmap_util.c | 6 +- > fs/xfs/xfs_file.c | 30 ++++++- > fs/xfs/xfs_inode.c | 8 +- > fs/xfs/xfs_inode.h | 1 + > fs/xfs/xfs_iomap.c | 3 +- > fs/xfs/xfs_iops.c | 11 ++- > fs/xfs/xfs_reflink.c | 23 ++++- > include/linux/dax.h | 5 ++ > include/linux/fs.h | 9 +- > 13 files changed, 270 insertions(+), 33 deletions(-) > > -- > 2.30.0 > > > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
