[PATCH v11 00/14] btrfs: add ioctls and send/receive support for reading/writing compressed data

Omar Sandoval
2021-09-01T17:01:29Z

From: Omar Sandoval <osandov@fb.com>

This series has three parts: new Btrfs ioctls for reading/writing
compressed data, support for sending compressed data via Btrfs send, and
btrfs-progs support for sending/receiving compressed data and writing it
with the new ioctl.

Patches 1 and 2 are VFS changes exporting a couple of helpers for checks
needed by reads and writes. Patches 3-7 are preparatory Btrfs changes
for compressed reads and writes. Patch 8 adds the compressed read ioctl
and patch 9 adds the compressed write ioctl.

The main use-case for this interface 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.

Patches 10-14 add the Btrfs send support. See the previous posting for
more details and benchmarks [1]. Patches 10-12 prepare some protocol
changes for send stream v2. Patch 13 implements compressed send. Patch
14 enables send stream v2 and compressed send in the send ioctl when
requested.

These patches are based on Dave Sterba's Btrfs misc-next branch [2],
which is in turn currently based on v5.14-rc7. Test cases are here [3].

Changes since v10 [4]:

Addressed Dave's and Nikolay's comments, mostly stylistic.

- Renamed __generic_write_checks() to generic_write_checks_count().
- Add missing count == 0 check to generic_write_checks_count().
- Used in_range() macro in btrfs_csum_one_bio().
- Renamed page_offsets variable to use_page_offsets in
btrfs_csum_one_bio().
- Removed conditional on offset increment in btrfs_csum_one_bio().
- Fixed stale reference to RWF_ENCODED in comment.

1: https://lore.kernel.org/linux-btrfs/cover.1615922753.git.osandov@fb.com/
2: https://github.com/kdave/btrfs-devel/tree/misc-next
3: https://github.com/osandov/xfstests/tree/btrfs-encoded-io
4: https://lore.kernel.org/linux-btrfs/cover.1629234193.git.osandov@fb.com/

Omar Sandoval (14):
fs: export rw_verify_area()
fs: export variant of generic_write_checks without iov_iter
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: add definitions + documentation for encoded I/O ioctls
btrfs: add BTRFS_IOC_ENCODED_READ
btrfs: add BTRFS_IOC_ENCODED_WRITE
btrfs: add send stream v2 definitions
btrfs: send: write larger chunks when using stream v2
btrfs: send: allocate send buffer with alloc_page() and vmap() for v2
btrfs: send: send compressed extents with encoded writes
btrfs: send: enable support for stream v2 and compressed writes

fs/btrfs/compression.c | 12 +-
fs/btrfs/compression.h | 6 +-
fs/btrfs/ctree.h | 17 +-
fs/btrfs/delalloc-space.c | 18 +-
fs/btrfs/file-item.c | 32 +-
fs/btrfs/file.c | 68 ++-
fs/btrfs/inode.c | 911 +++++++++++++++++++++++++++++++++----
fs/btrfs/ioctl.c | 213 +++++++++
fs/btrfs/ordered-data.c | 124 ++---
fs/btrfs/ordered-data.h | 25 +-
fs/btrfs/relocation.c | 2 +-
fs/btrfs/send.c | 307 +++++++++++--
fs/btrfs/send.h | 32 +-
fs/internal.h | 5 -
fs/read_write.c | 34 +-
include/linux/fs.h | 2 +
include/uapi/linux/btrfs.h | 149 +++++-
17 files changed, 1686 insertions(+), 271 deletions(-)

The btrfs-progs patches were written by Boris Burkov with some updates
from me. Patches 1-4 are preparation. Patch 5 implements encoded writes.
Patch 6 implements the fallback to decompressing. Patches 7 and 8
implement the other commands. Patch 9 adds the new `btrfs send` options.
Patch 10 adds a test case.

Changes from v10:

- Fixed feature fallback to check for ENOTTY instead of EOPNOTSUPP.

Boris Burkov (10):
btrfs-progs: receive: support v2 send stream larger tlv_len
btrfs-progs: receive: dynamically allocate sctx->read_buf
btrfs-progs: receive: support v2 send stream DATA tlv format
btrfs-progs: receive: add send stream v2 cmds and attrs to send.h
btrfs-progs: receive: process encoded_write commands
btrfs-progs: receive: encoded_write fallback to explicit decode and
write
btrfs-progs: receive: process fallocate commands
btrfs-progs: receive: process setflags ioctl commands
btrfs-progs: send: stream v2 ioctl flags
btrfs-progs: receive: add tests for basic encoded_write send/receive

Documentation/btrfs-receive.asciidoc | 4 +
Documentation/btrfs-send.asciidoc | 16 +-
cmds/receive-dump.c | 31 +-
cmds/receive.c | 347 +++++++++++++++++-
cmds/send.c | 54 ++-
common/send-stream.c | 157 ++++++--
common/send-stream.h | 7 +
ioctl.h | 149 +++++++-
libbtrfsutil/btrfs.h | 17 +-
send.h | 19 +-
.../049-receive-write-encoded/test.sh | 114 ++++++
11 files changed, 871 insertions(+), 44 deletions(-)
create mode 100755 tests/misc-tests/049-receive-write-encoded/test.sh

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2.33.0