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    Subject[PATCH v7 0/2] New zonefs file system
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    zonefs is a very simple file system exposing each zone of a zoned block
    device as a file. Unlike a regular file system with 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.
    Files representing sequential write zones of the device must be written
    sequentially starting from the end of the file (append only writes).

    zonefs is not a POSIX compliant file system. It's 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.

    Changes from v6:
    * Fixed documentation as suggested by Randy.

    Changes from v5:
    * Added simple description of zoned block devices to the documentation,
    as suggested by Johannes.
    * Added a 64-char max label field to the super block to allow label
    based identification of volumes using libblkid (checked with a patch
    to libblkid).

    Changes from v4:
    * Use octal values for file and directory permissions
    * Set initial directory permissions to 0555 (no write permission)
    * Prevent setting write permissions for directories

    Changes from v3:
    * Fixed many typos in the documentation
    * Use symbolic file permission macros instead of octal values
    (checkpatch.pl complains about this)

    Changes from v2:
    * Address comments and suggestions from Darrick:
    - Make the inode of OFFLINE and READONLY zones immutable when
    mounting. Also do this during zone information check after an IO
    error.
    - Change super block CRC seed to ~0.
    - Avoid potential compiler warning in zonefs_create_zgroup().
    * Fixed endianness related compilation warning detected by kbuild bot.

    Changes from v1:
    * Fixed comment typo
    * Improved documentation as suggested by Hannes

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

    Documentation/filesystems/zonefs.txt | 241 ++++++
    MAINTAINERS | 10 +
    fs/Kconfig | 1 +
    fs/Makefile | 1 +
    fs/zonefs/Kconfig | 9 +
    fs/zonefs/Makefile | 4 +
    fs/zonefs/super.c | 1177 ++++++++++++++++++++++++++
    fs/zonefs/zonefs.h | 175 ++++
    include/uapi/linux/magic.h | 1 +
    9 files changed, 1619 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

    --
    2.24.1

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