Add libbtrfsutil
Currently, users wishing to manage Btrfs filesystems programatically
have to shell out to btrfs-progs and parse the output. This isn't ideal.
The goal of libbtrfsutil is to provide a library version of as many of
the operations of btrfs-progs as possible and to migrate btrfs-progs to
use it.
Rather than simply refactoring the existing btrfs-progs code, the code
has to be written from scratch for a couple of reasons:
* A lot of the btrfs-progs code was not designed with a nice library API
in mind in terms of reusability, naming, and error reporting.
* libbtrfsutil is licensed under the LGPL, whereas btrfs-progs is under
the GPL, which makes it dubious to directly copy or move the code.
Eventually, most of the low-level btrfs-progs code should either live in
libbtrfsutil or the shared kernel/userspace filesystem code, and
btrfs-progs will just be the CLI wrapper.
This first commit just includes the build system changes, license,
README, and error reporting helper.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-02-15 19:04:47 +00:00
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libbtrfsutil
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============
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libbtrfsutil is a library for managing Btrfs filesystems. It is licensed under
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the LGPL. libbtrfsutil provides interfaces for a subset of the operations
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2017-12-18 08:31:25 +00:00
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offered by the `btrfs` command line utility. It also includes official Python
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bindings (Python 3 only).
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Add libbtrfsutil
Currently, users wishing to manage Btrfs filesystems programatically
have to shell out to btrfs-progs and parse the output. This isn't ideal.
The goal of libbtrfsutil is to provide a library version of as many of
the operations of btrfs-progs as possible and to migrate btrfs-progs to
use it.
Rather than simply refactoring the existing btrfs-progs code, the code
has to be written from scratch for a couple of reasons:
* A lot of the btrfs-progs code was not designed with a nice library API
in mind in terms of reusability, naming, and error reporting.
* libbtrfsutil is licensed under the LGPL, whereas btrfs-progs is under
the GPL, which makes it dubious to directly copy or move the code.
Eventually, most of the low-level btrfs-progs code should either live in
libbtrfsutil or the shared kernel/userspace filesystem code, and
btrfs-progs will just be the CLI wrapper.
This first commit just includes the build system changes, license,
README, and error reporting helper.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2018-02-15 19:04:47 +00:00
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Development
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-----------
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The [development process for btrfs-progs](../README.md#development) applies.
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libbtrfsutil only includes operations that are done through the filesystem and
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ioctl interface, not operations that modify the filesystem directly (e.g., mkfs
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or fsck). This is by design but also a legal necessity, as the filesystem
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implementation is GPL but libbtrfsutil is LGPL. That is also why the
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libbtrfsutil code is a reimplementation of the btrfs-progs code rather than a
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refactoring. Be wary of this when porting functionality.
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libbtrfsutil is semantically versioned separately from btrfs-progs. It is the
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maintainers' responsibility to bump the version as needed (at most once per
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release of btrfs-progs).
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A few guidelines:
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* All interfaces must be documented in `btrfsutil.h` using the kernel-doc style
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* Error codes should be specific about what _exactly_ failed
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* Functions should have a path and an fd variant whenever possible
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* Spell out terms in function names, etc. rather than abbreviating whenever
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possible
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* Don't require the Btrfs UAPI headers for any interfaces (e.g., instead of
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directly exposing a type from `linux/btrfs_tree.h`, abstract it away in a
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type specific to `libbtrfsutil`)
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* Preserve API and ABI compatability at all times (i.e., we don't want to bump
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the library major version if we don't have to)
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2017-12-18 08:31:25 +00:00
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* Include Python bindings for all interfaces
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* Write tests for all interfaces
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