[GIT PULL] New zonefs file system for 5.6-rc1

[Damien Le Moal]

Hi Linus,

Here is a pull request for the new zonefs file system (described briefly
below). Please consider it for addition to kernel 5.6.

The following changes since commit d5226fa6dbae0569ee43ecfc08bdcd6770fc4755:

  Linux 5.5 (2020-01-26 16:23:03 -0800)

are available in the Git repository at:

  ssh://git@xxxxxxxxxxxxxxxxxxx/pub/scm/linux/kernel/git/dlemoal/zonefs.git/ tags/zonefs-5.6-rc1

for you to fetch changes up to fcb9c24bef3d1d0942c50fb25fbb8ab45c7c3753:

  zonefs: Add documentation (2020-02-07 14:40:13 +0900)

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fs: New zonefs file system

Zonefs is a very simple file system exposing each zone of a zoned block
device as a file.

Unlike a regular file system with native zoned block device support
(e.g. f2fs or the on-going btrfs effort), zonefs does not hide the
sequential write constraint of zoned block devices to the user. As a
result, zonefs is not a POSIX compliant file system. Its goal is to
simplify the implementation of zoned block devices support in
applications by replacing raw block device file accesses with a richer
file based API, avoiding relying on direct block device file ioctls
which may be more obscure to developers.

One example of this approach is the implementation of LSM
(log-structured merge) tree structures (such as used in RocksDB and
LevelDB) on zoned block devices by allowing SSTables to be stored in a
zone file similarly to a regular file system rather than as a range of
sectors of a zoned device. The introduction of the higher level
construct "one file is one zone" can help reducing the amount of changes
needed in the application while at the same time allowing the use of
zoned block devices with various programming languages other than C.

Zonefs IO management implementation uses the new iomap generic code.
Zonefs has been successfully tested using a functional test suite
(available with zonefs userland format tool on github) and a prototype
implementation of LevelDB on top of zonefs.

Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>

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Damien Le Moal (2):
      fs: New zonefs file system
      zonefs: Add documentation

 Documentation/filesystems/zonefs.txt |  404 ++++++++++
 MAINTAINERS                          |   10 +
 fs/Kconfig                           |    1 +
 fs/Makefile                          |    1 +
 fs/zonefs/Kconfig                    |    9 +
 fs/zonefs/Makefile                   |    4 +
 fs/zonefs/super.c                    | 1439 ++++++++++++++++++++++++++++++++++
 fs/zonefs/zonefs.h                   |  189 +++++
 include/uapi/linux/magic.h           |    1 +
 9 files changed, 2058 insertions(+)
 create mode 100644 Documentation/filesystems/zonefs.txt
 create mode 100644 fs/zonefs/Kconfig
 create mode 100644 fs/zonefs/Makefile
 create mode 100644 fs/zonefs/super.c
 create mode 100644 fs/zonefs/zonefs.h