From: Omar Sandoval <osan...@fb.com> 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 .
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. The patches implementing the send/receive support will be sent shortly. Patches 1-3 add the VFS support and UAPI. Patch 4 is a fix that this series depends on; it can be merged independently. Patches 5-8 are Btrfs prep patches. Patch 9 adds Btrfs encoded read support and patch 10 adds Btrfs encoded write support. These patches are based on Dave Sterba's Btrfs misc-next branch , which is in turn currently based on v5.12-rc3. Changes since v7 : - Rebased on current kdave/misc-next (v5.12-rc3). Omar Sandoval (10): iov_iter: add copy_struct_from_iter() fs: add O_ALLOW_ENCODED open flag fs: add RWF_ENCODED for reading/writing compressed data btrfs: fix check_data_csum() error message for direct I/O 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 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-btrfs/cover.1611346706.git.osan...@fb.com/ 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 | 46 +- fs/btrfs/inode.c | 936 ++++++++++++++++++++--- 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 + fs/read_write.c | 168 +++- include/linux/encoded_io.h | 17 + include/linux/fcntl.h | 2 +- include/linux/fs.h | 13 + include/linux/uio.h | 2 + include/uapi/asm-generic/fcntl.h | 4 + include/uapi/linux/encoded_io.h | 30 + include/uapi/linux/fs.h | 5 +- lib/iov_iter.c | 82 ++ 26 files changed, 1378 insertions(+), 201 deletions(-) create mode 100644 Documentation/filesystems/encoded_io.rst create mode 100644 include/linux/encoded_io.h create mode 100644 include/uapi/linux/encoded_io.h -- 2.30.2