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btrfs-progs: docs: updates, formatting, status page 

- formatting, typo fixes, corrections
- cross references
- enhancements
- revised and colored status page
- ioctl updates

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2023-06-01 01:14:47 +02:00
parent 99ed2a64d8
commit 972ea8c8b3
13 changed files with 454 additions and 198 deletions
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11
Documentation/Common-features.rst
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@ -16,8 +16,13 @@ statx
*stat*
fallocate modes
the *fallocate* syscall allows to manipulate file extents like punching
holes, preallocation or zeroing a range
the *fallocate* syscall allows to manipulate file extents
Supported modes:
- keep size (FALLOC_FL_KEEP_SIZE)
- hole punching (FALLOC_FL_PUNCH_HOLE)
- zero range (FALLOC_FL_ZERO_RANGE)
FIEMAP
an ioctl that enumerates file extents, related tool is :command:`filefrag`
@ -39,7 +44,7 @@ xattr, acl
cross-rename
mode of *renameat2* syscall that can atomically swap 2 directory
entries (files/directories/subvolumes)
entries (files/directories/subvolumes/symlinks) within the same filesystem
File attributes, XFLAGS

3
Documentation/Custom-ioctls.rst
View File

@ -19,3 +19,6 @@ a command if available:
which is also exported in :file:`/sys/fs/btrfs/`
- query/set a subset of features on a mounted filesystem
Programming documentaion of the ioctls is in the manual page
:doc:`btrfs-ioctl(2)<btrfs-ioctl>`.

2
Documentation/Feature-by-version.rst
View File

@ -71,7 +71,7 @@ features see [[Status]] page.
.. note::
Disabled since 3.14 (and backported to some stable kernel versions)
due to problems. Will be enabled in the future.
due to problems. Has been completely removed in 5.6.
3.9 - lightweight send
A mode of *send* that does not add the actual file data to the stream

12
Documentation/Interoperability.rst
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@ -3,18 +3,28 @@
Interoperability
================
.. _interop-nfs:
NFS
---
.. _interop-samba:
Samba
-----
.. _interop-cgroups:
cgroups
-------
.. _interop-fsverity:
fsverity
--------
.. _interop-idmapped:
idmapped mounts
---------------
@ -27,5 +37,7 @@ overlayfs
SELinux
-------
.. _interop-io-uring:
io_uring
--------

2
Documentation/Source-repositories.rst
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@ -108,6 +108,6 @@ patch page to the command:
.. code-block:: bash
$ wget -O - '<nowiki>https://patchwork.kernel.org/patch/123456/mbox</nowiki>' | git am -
$ wget -O - 'https://patchwork.kernel.org/patch/123456/mbox' | git am -
You may want to add *--reject*, or decide otherwise what to do with the patch.

248
Documentation/Status.rst
View File

@ -13,7 +13,7 @@ in meeting your performance expectations for your specific workload.
Combination of features can vary in performance, the table does not
cover all possibilities.
**The table is based on the latest released linux kernel: 6.2**
**The table is based on the latest released linux kernel: 6.3**
The columns for each feature reflect the status of the implementation
in following ways:
@ -30,6 +30,10 @@ in following ways:
- **Unstable**: do not use for other then testing purposes, known
severe problems, missing implementation of some core parts
.. role:: statusok
.. role:: statusmok
.. role:: statusunst
.. list-table::
:header-rows: 1
@ -37,180 +41,188 @@ in following ways:
- Stability
- Performance
- Notes
* - discard (synchronous)
- OK
* - :doc:`discard (synchronous)<Trim>`
- :statusok:`OK`
-
- mounted with `-o discard` (has performance implications), also see `fstrim`
* - discard (asynchronous)
- OK
* - :doc:`discard (asynchronous)<Trim>`
- :statusok:`OK`
-
- mounted with `-o discard=async` (improved performance)"
- mounted with `-o discard=async` (improved performance)
* - Autodefrag
- OK
- :statusok:`OK`
-
-
* - Defrag
- mostly OK
* - :doc:`Defrag<Defragmentation>`
- :statusmok:`mostly OK`
-
- extents get unshared (see below)
* - Compression
- OK (4.14)
* - :doc:`Compression<Compression>`
- :statusok:`OK`
-
-
* - Out-of-band dedupe
- OK
- mostly OK
* - :doc:`Out-of-band dedupe<Deduplication>`
- :statusok:`OK`
- :statusmok:`mostly OK`
- (reflink), heavily referenced extents have a noticeable performance hit (see below)
* - File range cloning
- OK
- mostly OK
* - :doc:`File range cloning<Reflink>`
- :statusok:`OK`
- :statusmok:`mostly OK`
- (reflink), heavily referenced extents have a noticeable performance hit (see below)
* - More checksumming algorithms
- OK
* - :doc:`More checksumming algorithms<Checksumming>`
- :statusok:`OK`
- OK
-
* - Auto-repair
- OK
* - :doc:`Auto-repair<Auto-repair>`
- :statusok:`OK`
- OK
- automatically repair from a correct spare copy if possible (DUP, RAID1, RAID10, RAID56)
* - Scrub
- OK
* - :doc:`Scrub<Scrub>`
- :statusok:`OK`
- OK
-
* - Scrub + RAID56
- mostly OK
- :statusmok:`mostly OK`
- mostly OK
-
* - nodatacow
- OK
- :statusok:`OK`
- OK
-
* - Device replace
- mostly OK
* - :doc:`Device replace<Volume-management>`
- :statusmok:`mostly OK`
- mostly OK
- (see below)
* - Degraded mount
- OK (4.14)
- :statusok:`OK`
- n/a
-
* - Single (block group profile)
- OK
* - :ref:`Single (block group profile)<mkfs-section-profiles>`
- :statusok:`OK`
- OK
-
* - DUP (block group profile)
- OK
* - :ref:`DUP (block group profile)<mkfs-section-profiles>`
- :statusok:`OK`
- OK
-
* - RAID0
- OK
* - :ref:`RAID0<mkfs-section-profiles>`
- :statusok:`OK`
- OK
-
* - RAID1
- OK
* - :ref:`RAID1<mkfs-section-profiles>`
- :statusok:`OK`
- mostly OK
- reading from mirrors in parallel can be optimized further (see below)
* - RAID1C3
- OK
* - :ref:`RAID1C3<mkfs-section-profiles>`
- :statusok:`OK`
- mostly OK
- reading from mirrors in parallel can be optimized further (see below)
* - RAID1C4
- OK
* - :ref:`RAID1C4<mkfs-section-profiles>`
- :statusok:`OK`
- mostly OK
- reading from mirrors in parallel can be optimized further (see below)
* - RAID10
- OK
* - :ref:`RAID10<mkfs-section-profiles>`
- :statusok:`OK`
- mostly OK
- reading from mirrors in parallel can be optimized further (see below)
* - RAID56
- unstable
* - :ref:`RAID56<mkfs-section-profiles>`
- :statusunst:`unstable`
- n/a
- (see below)
* - Mixed block groups
- OK
- :statusok:`OK`
- OK
-
* - Filesystem resize
- OK
* - :doc:`Filesystem resize<Resize>`
- :statusok:`OK`
- OK
- shrink, grow
* - Balance
- OK
* - :doc:`Balance<Balance>`
- :statusok:`OK`
- OK
- balance + qgroups can be slow when there are many snapshots
* - Offline UUID change
- OK
- :statusok:`OK`
- OK
-
* - Metadata UUID change
- OK
- :statusok:`OK`
- OK
-
* - Subvolumes, snapshots
- OK
* - :doc:`Subvolumes, snapshots<Subvolumes>`
- :statusok:`OK`
- OK
-
* - Send
- OK
* - :doc:`Send<Send-receive>`
- :statusok:`OK`
- OK
-
* - Receive
- OK
* - :doc:`Receive<Send-receive>`
- :statusok:`OK`
- OK
-
* - Seeding
- OK
* - :doc:`Seeding<Seeding-device>`
- :statusok:`OK`
- OK
-
* - Quotas, qgroups
- mostly OK
* - :doc:`Quotas, qgroups<Qgroups>`
- :statusmok:`mostly OK`
- mostly OK
- qgroups with many snapshots slows down balance
* - Swapfile
- OK
* - :doc:`Swapfile<Swapfile>`
- :statusok:`OK`
- n/a
- with some limitations
* - NFS
- OK
* - :ref:`NFS<interop-nfs>`
- :statusok:`OK`
- OK
-
* - cgroups
- OK
* - :ref:`cgroups<interop-cgroups>`
- :statusok:`OK`
- OK
- IO controller
* - Samba
- OK
* - :ref:`Samba<interop-samba>`
- :statusok:`OK`
- OK
- compression, server-side copies, snapshots
* - io_uring
- OK
* - :ref:`io_uring<interop-io-uring>`
- :statusok:`OK`
- OK
-
* - fsverity
- OK
* - :ref:`fsverity<interop-fsverity>`
- :statusok:`OK`
- OK
-
* - idmapped mount
- OK
* - :ref:`idmapped mount<interop-idmapped>`
- :statusok:`OK`
- OK
-
* - Free space tree
- OK (4.9)
* - :ref:`Free space tree<mkfs-feature-free-space-tree>`
- :statusok:`OK`
-
-
* - no-holes
- OK
* - Block group tree
- :statusok:`OK`
-
-
* - :ref:`no-holes<mkfs-feature-no-holes>`
- :statusok:`OK`
- OK
-
* - skinny-metadata
- OK
* - :ref:`skinny-metadata<mkfs-feature-skinny-metadata>`
- :statusok:`OK`
- OK
-
* - extended-refs
- OK
* - :ref:`extended-refs<mkfs-feature-extended-refs>`
- :statusok:`OK`
- OK
-
* - zoned mode
* - :doc:`Subpage block size<Subpage>`
- :statusmok:`mostly OK`
- mostly OK
-
* - :doc:`Zoned mode<Zoned-mode>`
- :statusmok:`mostly OK`
- mostly OK
- there are known bugs, use only for testing
@ -223,6 +235,70 @@ Please open an issue if:
- a reference could be enhanced by an actual link to documentation
(wiki, manual pages)
Subpage block size
------------------
Most commonly used page sizes are 4KiB, 16KiB and 64KiB. All combinations with
a 4KiB sector size filesystems are supported. Some features are not compatible
with subpage or require another feature to work:
.. list-table::
:header-rows: 1
* - Feature
- Status
- Notes
* - Inline files
- unsupported
- The max_inline mount option value is ignored
* - Free space cache v1
- unsupported
- Free space tree is mandatory
* - Compression
- partial support
- Only page-aligned ranges can be compressed
Zoned mode
----------
.. list-table::
:header-rows: 1
* - Feature
- Status
- Notes
* - Boot
- incompatible
- The blocks where partition table is stored is used for super block
* - Mixed block groups
- incompatible
- Interleaving data and metadata would lead to out of order write
* - NODATACOW
- incompatible
- In-place overwrite
* - fallocate
- incompatible
- Preallocation of blocks would require an out of order write
* - Free space cache v1
- incompatible
- Cache data are updated in a NODATACOW-way
* - Free space tree
- supported
-
* - fstrim
- not implemented
- This would require free space v1
* - single profile
- supported
- Both data and metadata
* - DUP profile
- partial support
- Only for metadata
* - RAID (all)
- not implemented
- This requires raid-stripe-tree feature which is still work in progress
Details that do not fit the table
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@ -275,10 +351,10 @@ continue to be mountable and usable by newer kernels.
The core of the on-disk format that comprises building blocks of the
filesystem:
- layout of the main data structures, eg. superblock, b-tree nodes,
- layout of the main data structures, e.g. superblock, b-tree nodes,
b-tree keys, block headers
- the COW mechanism, based on the original design of Ohad Rodeh's paper
"Shadowing and clones"
"B-trees, Shadowing and Clones" (http://sylab-srv.cs.fiu.edu/lib/exe/fetch.php?media=paperclub:shadow_btree.pdf)
Newly introduced features build on top of the above and could add
specific structures. If a backward compatibility is not possible to

43
Documentation/Subpage.rst
View File

@ -10,16 +10,13 @@ pages, like 64KiB on 64bit ARM or PowerPC. This means filesystems created
with 64KiB sector size cannot be mounted on a system with 4KiB page size.
While with subpage support, systems with 64KiB page size can create (still needs
"-s 4k" option for :command:`mkfs.btrfs`) and mount filesystems with 4KiB sectorsize,
allowing us to push 4KiB sectorsize as default sectorsize for all platforms in the
near future.
"-s 4k" option for :command:`mkfs.btrfs`) and mount filesystems with 4KiB sectorsize.
Requirements, limitations
-------------------------
The initial subpage support has been added in v5.15, although it's still
considered as experimental at the time of writing (v5.18), most features are
already working without problems.
considered as experimental, most features are already working without problems.
End users can mount filesystems with 4KiB sectorsize and do their usual
workload, while should not notice any obvious change, as long as the initial
@ -27,37 +24,25 @@ mount succeeded (there are cases a mount will be rejected though).
The following features has some limitations for subpage:
- RAID56 support
This support is already queued for v5.19 cycle.
Any fs with RAID56 chunks will be rejected at mount time for now.
- Supported page sizes: 4KiB, 8KiB, 16KiB, 32KiB, 64KiB
- Support for page size other than 64KiB
The support for other page sizes (16KiB, 32KiB and more) are already queued
for v5.19 cycle.
Initially the subpage support is only for 64KiB support, but the design makes
it pretty easy to enable support for other page sizes.
- Supported filesystem sector sizes on a given host are exported in
:file:`/sys/fs/btrfs/features/supported_sectorsizes`
- No inline extent creation
This is an artificial limit, to prevent mixed inline and regular extents.
- No inline extents
It's possible to create mixed inline and regular extents even with
non-subpage mount for certain corner cases, it's way easier to create such
mixed extents for subpage.
This is an artificial limitation, to prevent mixed inline and regular extents.
Thus max_inline mount option will be silently ignored for subpage mounts,
and it always acts as "max_inline=0".
- Compression write is limited to page aligned ranges
Compression write for subpage is introduced in v5.16, with the limitation
that only page aligned range can be compressed.
This limitation is due to how btrfs handles delayed allocation.
- Compression writes are limited to page aligned ranges
Compression write for subpage has been introduced in v5.16, with the
limitation that only page aligned range can be compressed. This limitation
is due to how btrfs handles delayed allocation.
- No support for v1 space cache
V1 space cache is considered deprecated, and we're defaulting to v2 cache
in btrfs-progs already.
The old v1 cache has quite some hard coded page size usage, and consider it
is already deprecated, we force v2 cache for subpage.
- Slightly higher memory usage for scrub
This is due to how we allocate pages for scrub, and will be fixed in the coming
releases soon.
The old v1 cache has quite some hard coded page size usage, and considering
it already deprecated, we force v2 cache for subpage.

18
Documentation/_static/style.css
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@ -1,3 +1,21 @@
.wy-nav-content {
max-width: 1200px !important;
}
.green {
color: green;
}
.statusok {
color: green;
}
.statusmok {
/* color: orange; */
/* color: #ffae42; */
color: darkorange;
}
.statusunst {
color: red;
}

2
Documentation/btrfs-device.rst
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@ -14,7 +14,7 @@ The :command:`btrfs device` command group is used to manage devices of the btrfs
DEVICE MANAGEMENT
-----------------
.. include ch-volume-management-intro.rst
.. include:: ch-volume-management-intro.rst
SUBCOMMAND
----------

274
Documentation/btrfs-ioctl.rst
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@ -1,4 +1,4 @@
btrfs-ioctl(3)
btrfs-ioctl(2)
==============
NAME
@ -21,6 +21,8 @@ and a formerly private ioctl number could become available on the VFS level.
DATA STRUCTURES AND DEFINITIONS
-------------------------------
.. _struct_btrfs_ioctl_vol_args:
.. code-block:: c
struct btrfs_ioctl_vol_args {
@ -28,6 +30,8 @@ DATA STRUCTURES AND DEFINITIONS
char name[BTRFS_PATH_NAME_MAX + 1];
};
.. _struct_btrfs_ioctl_vol_args_v2:
.. code-block:: c
struct btrfs_ioctl_vol_args_v2 {
@ -48,6 +52,8 @@ DATA STRUCTURES AND DEFINITIONS
};
};
.. _struct_btrfs_ioctl_get_subvol_info_args:
.. code-block:: c
struct btrfs_ioctl_get_subvol_info_args {
@ -158,65 +164,189 @@ cases are documented.
LIST OF IOCTLS
--------------
* BTRFS_IOC_SUBVOL_CREATE -- (obsolete) create a subvolume
* BTRFS_IOC_SNAP_CREATE
* BTRFS_IOC_DEFRAG
* BTRFS_IOC_RESIZE
* BTRFS_IOC_SCAN_DEV
* BTRFS_IOC_SYNC
* BTRFS_IOC_CLONE
* BTRFS_IOC_ADD_DEV
* BTRFS_IOC_RM_DEV
* BTRFS_IOC_BALANCE
* BTRFS_IOC_CLONE_RANGE
* BTRFS_IOC_SUBVOL_CREATE
* BTRFS_IOC_SNAP_DESTROY
* BTRFS_IOC_DEFRAG_RANGE
* BTRFS_IOC_TREE_SEARCH
* BTRFS_IOC_TREE_SEARCH_V2
* BTRFS_IOC_INO_LOOKUP
* BTRFS_IOC_DEFAULT_SUBVOL
* BTRFS_IOC_SPACE_INFO
* BTRFS_IOC_START_SYNC
* BTRFS_IOC_WAIT_SYNC
* BTRFS_IOC_SNAP_CREATE_V2 -- create a snapshot of a subvolume
* BTRFS_IOC_SUBVOL_CREATE_V2 -- create a subvolume
* BTRFS_IOC_SUBVOL_GETFLAGS -- get flags of a subvolume
* BTRFS_IOC_SUBVOL_SETFLAGS -- set flags of a subvolume
* BTRFS_IOC_SCRUB
* BTRFS_IOC_SCRUB_CANCEL
* BTRFS_IOC_SCRUB_PROGRESS
* BTRFS_IOC_DEV_INFO
* BTRFS_IOC_FS_INFO
* BTRFS_IOC_BALANCE_V2
* BTRFS_IOC_BALANCE_CTL
* BTRFS_IOC_BALANCE_PROGRESS
* BTRFS_IOC_INO_PATHS
* BTRFS_IOC_LOGICAL_INO
* BTRFS_IOC_SET_RECEIVED_SUBVOL
* BTRFS_IOC_SEND
* BTRFS_IOC_DEVICES_READY
* BTRFS_IOC_QUOTA_CTL
* BTRFS_IOC_QGROUP_ASSIGN
* BTRFS_IOC_QGROUP_CREATE
* BTRFS_IOC_QGROUP_LIMIT
* BTRFS_IOC_QUOTA_RESCAN
* BTRFS_IOC_QUOTA_RESCAN_STATUS
* BTRFS_IOC_QUOTA_RESCAN_WAIT
* BTRFS_IOC_GET_FSLABEL
* BTRFS_IOC_SET_FSLABEL
* BTRFS_IOC_GET_DEV_STATS
* BTRFS_IOC_DEV_REPLACE
* BTRFS_IOC_FILE_EXTENT_SAME
* BTRFS_IOC_GET_FEATURES
* BTRFS_IOC_SET_FEATURES
* BTRFS_IOC_GET_SUPPORTED_FEATURES
* BTRFS_IOC_RM_DEV_V2
* BTRFS_IOC_LOGICAL_INO_V2
* BTRFS_IOC_GET_SUBVOL_INFO -- get information about a subvolume
* BTRFS_IOC_GET_SUBVOL_ROOTREF
* BTRFS_IOC_INO_LOOKUP_USER
* BTRFS_IOC_SNAP_DESTROY_V2 -- destroy a (snapshot or regular) subvolume
.. list-table::
:header-rows: 1
* - Name
- Description
- Data
* - BTRFS_IOC_SUBVOL_CREATE
- (obsolete) create a subvolume
- :ref:`struct btrfs_ioctl_vol_args<struct_btrfs_ioctl_vol_args>`
* - BTRFS_IOC_SNAP_CREATE
-
-
* - BTRFS_IOC_DEFRAG
-
-
* - BTRFS_IOC_RESIZE
-
-
* - BTRFS_IOC_SCAN_DEV
-
-
* - BTRFS_IOC_SYNC
-
-
* - BTRFS_IOC_CLONE
-
-
* - BTRFS_IOC_ADD_DEV
-
-
* - BTRFS_IOC_RM_DEV
-
-
* - BTRFS_IOC_BALANCE
-
-
* - BTRFS_IOC_CLONE_RANGE
-
-
* - BTRFS_IOC_SUBVOL_CREATE
-
-
* - BTRFS_IOC_SNAP_DESTROY
-
-
* - BTRFS_IOC_DEFRAG_RANGE
-
-
* - BTRFS_IOC_TREE_SEARCH
-
-
* - BTRFS_IOC_TREE_SEARCH_V2
-
-
* - BTRFS_IOC_INO_LOOKUP
-
-
* - BTRFS_IOC_DEFAULT_SUBVOL
-
-
* - BTRFS_IOC_SPACE_INFO
-
-
* - BTRFS_IOC_START_SYNC
-
-
* - BTRFS_IOC_WAIT_SYNC
-
-
* - :ref:`BTRFS_IOC_SNAP_CREATE_V2<BTRFS_IOC_SNAP_CREATE_V2>`
- create a snapshot of a subvolume
- :ref:`struct btrfs_ioctl_vol_args_v2<struct_btrfs_ioctl_vol_args_v2>`
* - :ref:`BTRFS_IOC_SUBVOL_CREATE_V2<BTRFS_IOC_SUBVOL_CREATE_V2>`
- create a subvolume
- :ref:`struct btrfs_ioctl_vol_args_v2<struct_btrfs_ioctl_vol_args_v2>`
* - :ref:`BTRFS_IOC_SUBVOL_GETFLAGS<BTRFS_IOC_SUBVOL_GETFLAGS>`
- get flags of a subvolume
- uint64_t
* - :ref:`BTRFS_IOC_SUBVOL_SETFLAGS<BTRFS_IOC_SUBVOL_SETFLAGS>`
- set flags of a subvolume
- uint64_t
* - BTRFS_IOC_SCRUB
-
-
* - BTRFS_IOC_SCRUB_CANCEL
-
-
* - BTRFS_IOC_SCRUB_PROGRESS
-
-
* - BTRFS_IOC_DEV_INFO
-
-
* - BTRFS_IOC_FS_INFO
-
-
* - BTRFS_IOC_BALANCE_V2
-
-
* - BTRFS_IOC_BALANCE_CTL
-
-
* - BTRFS_IOC_BALANCE_PROGRESS
-
-
* - BTRFS_IOC_INO_PATHS
-
-
* - BTRFS_IOC_LOGICAL_INO
-
-
* - BTRFS_IOC_SET_RECEIVED_SUBVOL
-
-
* - BTRFS_IOC_SEND
-
-
* - BTRFS_IOC_DEVICES_READY
-
-
* - BTRFS_IOC_QUOTA_CTL
-
-
* - BTRFS_IOC_QGROUP_ASSIGN
-
-
* - BTRFS_IOC_QGROUP_CREATE
-
-
* - BTRFS_IOC_QGROUP_LIMIT
-
-
* - BTRFS_IOC_QUOTA_RESCAN
-
-
* - BTRFS_IOC_QUOTA_RESCAN_STATUS
-
-
* - BTRFS_IOC_QUOTA_RESCAN_WAIT
-
-
* - BTRFS_IOC_GET_FSLABEL
-
-
* - BTRFS_IOC_SET_FSLABEL
-
-
* - BTRFS_IOC_GET_DEV_STATS
-
-
* - BTRFS_IOC_DEV_REPLACE
-
-
* - BTRFS_IOC_FILE_EXTENT_SAME
-
-
* - BTRFS_IOC_GET_FEATURES
-
-
* - BTRFS_IOC_SET_FEATURES
-
-
* - BTRFS_IOC_GET_SUPPORTED_FEATURES
-
-
* - BTRFS_IOC_RM_DEV_V2
-
-
* - BTRFS_IOC_LOGICAL_INO_V2
-
-
* - :ref:`BTRFS_IOC_GET_SUBVOL_INFO<BTRFS_IOC_GET_SUBVOL_INFO>`
- get information about a subvolume
- :ref:`struct btrfs_ioctl_get_subvol_info_args<struct_btrfs_ioctl_get_subvol_info_args>`
* - BTRFS_IOC_GET_SUBVOL_ROOTREF
-
-
* - BTRFS_IOC_INO_LOOKUP_USER
-
-
* - :ref:`BTRFS_IOC_SNAP_DESTROY_V2<BTRFS_IOC_SNAP_DESTROY_V2>`
- destroy a (snapshot or regular) subvolume
- :ref:`struct btrfs_ioctl_vol_args_v2<struct_btrfs_ioctl_vol_args_v2>`
DETAILED DESCRIPTION
--------------------
@ -225,7 +355,7 @@ BTRFS_IOC_SUBVOL_CREATE
~~~~~~~~~~~~~~~~~~~~~~~
.. note::
obsoleted by BTRFS_IOC_SUBVOL_CREATE_V2
obsoleted by :ref:`BTRFS_IOC_SUBVOL_CREATE_V2<BTRFS_IOC_SUBVOL_CREATE_V2>`
*(since: 3.0, obsoleted: 4.0)* Create a subvolume.
@ -237,7 +367,7 @@ BTRFS_IOC_SUBVOL_CREATE
* - ioctl fd
- file descriptor of the parent directory of the new subvolume
* - ioctl args
- struct btrfs_ioctl_vol_args
- :ref:`struct btrfs_ioctl_vol_args<struct_btrfs_ioctl_vol_args>`
* - args.fd
- ignored
* - args.name
@ -245,6 +375,8 @@ BTRFS_IOC_SUBVOL_CREATE
size is limited by Linux VFS to 255 characters and must not contain a slash
('/')
.. _BTRFS_IOC_SNAP_CREATE_V2:
BTRFS_IOC_SNAP_CREATE_V2
~~~~~~~~~~~~~~~~~~~~~~~~
@ -258,7 +390,7 @@ Create a snapshot of a subvolume.
* - ioctl fd
- file descriptor of the directory inside which to create the new snapshot
* - ioctl args
- struct btrfs_ioctl_vol_args_v2
- :ref:`struct btrfs_ioctl_vol_args_v2<struct_btrfs_ioctl_vol_args_v2>`
* - args.fd
- file descriptor of any directory inside the subvolume to snapshot
* - args.transid
@ -269,6 +401,8 @@ Create a snapshot of a subvolume.
* - name
- the name, under the ioctl fd, for the new subvolume
.. _BTRFS_IOC_SUBVOL_CREATE_V2:
BTRFS_IOC_SUBVOL_CREATE_V2
~~~~~~~~~~~~~~~~~~~~~~~~~~
@ -282,7 +416,7 @@ BTRFS_IOC_SUBVOL_CREATE_V2
* - ioctl fd
- file descriptor of the parent directory of the new subvolume
* - ioctl args
- struct btrfs_ioctl_vol_args_v2
- :ref:`struct btrfs_ioctl_vol_args_v2<struct_btrfs_ioctl_vol_args_v2>`
* - args.fd
- ignored
* - args.transid
@ -300,6 +434,8 @@ BTRFS_IOC_SUBVOL_CREATE_V2
* - devid
- ...
.. _BTRFS_IOC_SUBVOL_GETFLAGS:
BTRFS_IOC_SUBVOL_GETFLAGS
~~~~~~~~~~~~~~~~~~~~~~~~~
@ -316,6 +452,8 @@ Read the flags of a subvolume. The returned flags are either 0 or
* - ioctl args
- uint64_t
.. _BTRFS_IOC_SUBVOL_SETFLAGS:
BTRFS_IOC_SUBVOL_SETFLAGS
~~~~~~~~~~~~~~~~~~~~~~~~~
@ -331,6 +469,8 @@ Change the flags of a subvolume.
* - ioctl args
- uint64_t, either 0 or `BTRFS_SUBVOL_RDONLY`
.. _BTRFS_IOC_GET_SUBVOL_INFO:
BTRFS_IOC_GET_SUBVOL_INFO
~~~~~~~~~~~~~~~~~~~~~~~~~
@ -344,7 +484,9 @@ Get information about a subvolume.
* - ioctl fd
- file descriptor of the subvolume to examine
* - ioctl args
- struct btrfs_ioctl_get_subvol_info_args
- :ref:`struct btrfs_ioctl_get_subvol_info_args<struct_btrfs_ioctl_get_subvol_info_args>`
.. _BTRFS_IOC_SNAP_DESTROY_V2:
BTRFS_IOC_SNAP_DESTROY_V2
~~~~~~~~~~~~~~~~~~~~~~~~~
@ -363,7 +505,7 @@ Destroy a subvolume, which may or may not be a snapshot.
directory on the same filesystem as the subvolume to delete, but not
within the same subvolume
* - ioctl args
- struct btrfs_ioctl_vol_args_v2
- :ref:`struct btrfs_ioctl_vol_args_v2<struct_btrfs_ioctl_vol_args_v2>`
* - args.fd
- ignored
* - args.transid

8
Documentation/ch-flexibility.rst
View File

@ -4,12 +4,16 @@ or enabling some features on-the-fly.
* **dynamic inode creation** -- there's no fixed space or tables for tracking
inodes so the number of inodes that can be created is bounded by the metadata
space and it's utilization
space and its utilization
* **block group profile change on-the-fly** -- the block group profiles can be
changed on a mounted filesystem by running the balance operation and
specifying the conversion filters
specifying the conversion filters (see :doc:`balance<Balance>`.)
* **resize** -- the space occupied by the filesystem on each device can be
resized up (grow) or down (shrink) as long as the amount of data can be still
contained on the device
* **device management** -- devices can be added, removed or replaced without
requiring recreating the filesystem (mkfs), new redundancy options available
on more devices can be also utilized by rebalancing

19
Documentation/ch-zoned-intro.rst
View File

@ -17,15 +17,16 @@ to set various zone sizes.
Requirements, limitations
^^^^^^^^^^^^^^^^^^^^^^^^^
* all devices must have the same zone size
* maximum zone size is 8GiB
* minimum zone size is 4MiB
* mixing zoned and non-zoned devices is possible, the zone writes are emulated,
but this is namely for testing
* the super block is handled in a special way and is at different locations than on a non-zoned filesystem:
* primary: 0B (and the next two zones)
* secondary: 512GiB (and the next two zones)
* tertiary: 4TiB (4096GiB, and the next two zones)
* all devices must have the same zone size
* maximum zone size is 8GiB
* minimum zone size is 4MiB
* mixing zoned and non-zoned devices is possible, the zone writes are emulated,
but this is namely for testing
* the super block is handled in a special way and is at different locations than on a non-zoned filesystem:
* primary: 0B (and the next two zones)
* secondary: 512GiB (and the next two zones)
* tertiary: 4TiB (4096GiB, and the next two zones)
Incompatible features
^^^^^^^^^^^^^^^^^^^^^

10
Documentation/mkfs.btrfs.rst
View File

@ -241,6 +241,8 @@ mixed-bg
mixed data and metadata block groups, also set by option *--mixed*
.. _mkfs-feature-extended-refs:
extref
(default since btrfs-progs 3.12, kernel support since 3.7)
@ -254,11 +256,15 @@ raid56
extended format for RAID5/6, also enabled if RAID5 or RAID6 block groups
are selected
.. _mkfs-feature-skinny-metadata:
skinny-metadata
(default since btrfs-progs 3.18, kernel support since 3.10)
reduced-size metadata for extent references, saves a few percent of metadata
.. _mkfs-feature-no-holes:
no-holes
(default since btrfs-progs 5.15, kernel support since 3.14)
@ -278,6 +284,8 @@ quota
Enable quota support (qgroups). The qgroup accounting will be consistent,
can be used together with *--rootdir*. See also :doc:`btrfs-quota(8)<btrfs-quota>`.
.. _mkfs-feature-free-space-tree:
free-space-tree
(default since btrfs-progs 5.15, kernel support since 4.5)
@ -289,6 +297,8 @@ block-group-tree
Enable the block group tree to greatly reduce mount time for large filesystems.
.. _mkfs-section-profiles:
BLOCK GROUPS, CHUNKS, RAID
--------------------------