This series adds an API for reading compressed data on a filesystem without decompressing it as well as support for writing compressed data directly to the filesystem. As with the previous submissions, I've included a man page patch describing the API. I have test cases (including fsstress support) and example programs which I'll send up soon [1]. The main use-case is Btrfs send/receive: currently, when sending data from one compressed filesystem to another, the sending side decompresses the data and the receiving side recompresses it before writing it out. This is wasteful and can be avoided if we can just send and write compressed extents. Since the last posting of this series, I've implemented the send support and Boris Burkov has implemented the receive support using this interface; the speedup is significant. Those patches will be sent shortly. Patches 1-3 add the VFS support and UAPI. Patches 4-7 are Btrfs prep patches. Patch 8 adds Btrfs encoded read support and patch 9 adds Btrfs encoded write support. These patches are based on Dave Sterba's Btrfs misc-next branch [2], which is in turn based on v5.9-rc1. Changes since v4 [3]: - Rebased on kdave/misc-next. - Clarified the man pages in several places. 1: https://github.com/osandov/xfstests/tree/rwf-encoded 2: https://github.com/kdave/btrfs-devel/tree/misc-next 3: https://lore.kernel.org/linux-fsdevel/cover.1582930832.git.osandov@xxxxxx/ Omar Sandoval (9): iov_iter: add copy_struct_from_iter() fs: add O_ALLOW_ENCODED open flag fs: add RWF_ENCODED for reading/writing compressed data btrfs: don't advance offset for compressed bios in btrfs_csum_one_bio() btrfs: add ram_bytes and offset to btrfs_ordered_extent btrfs: support different disk extent size for delalloc btrfs: optionally extend i_size in cow_file_range_inline() btrfs: implement RWF_ENCODED reads btrfs: implement RWF_ENCODED writes Documentation/filesystems/encoded_io.rst | 74 ++ Documentation/filesystems/index.rst | 1 + arch/alpha/include/uapi/asm/fcntl.h | 1 + arch/parisc/include/uapi/asm/fcntl.h | 1 + arch/sparc/include/uapi/asm/fcntl.h | 1 + fs/btrfs/compression.c | 12 +- fs/btrfs/compression.h | 6 +- fs/btrfs/ctree.h | 9 +- fs/btrfs/delalloc-space.c | 18 +- fs/btrfs/file-item.c | 35 +- fs/btrfs/file.c | 55 +- fs/btrfs/inode.c | 904 ++++++++++++++++++++--- fs/btrfs/ordered-data.c | 80 +- fs/btrfs/ordered-data.h | 18 +- fs/btrfs/relocation.c | 4 +- fs/fcntl.c | 10 +- fs/namei.c | 4 + include/linux/fcntl.h | 2 +- include/linux/fs.h | 16 + include/linux/uio.h | 2 + include/uapi/asm-generic/fcntl.h | 4 + include/uapi/linux/fs.h | 33 +- lib/iov_iter.c | 82 ++ mm/filemap.c | 166 ++++- 24 files changed, 1336 insertions(+), 202 deletions(-) create mode 100644 Documentation/filesystems/encoded_io.rst -- 2.28.0
