diff options
Diffstat (limited to 'Documentation/filesystems/ext4')
| -rw-r--r-- | Documentation/filesystems/ext4/atomic_writes.rst | 10 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/bitmaps.rst | 7 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/blockgroup.rst | 11 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/dynamic.rst | 10 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/globals.rst | 15 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/index.rst | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/inode_table.rst | 9 | ||||
| -rw-r--r-- | Documentation/filesystems/ext4/overview.rst | 22 |
8 files changed, 49 insertions, 37 deletions
diff --git a/Documentation/filesystems/ext4/atomic_writes.rst b/Documentation/filesystems/ext4/atomic_writes.rst index f65767df3620..aeb47ace738d 100644 --- a/Documentation/filesystems/ext4/atomic_writes.rst +++ b/Documentation/filesystems/ext4/atomic_writes.rst @@ -148,10 +148,10 @@ reserved during: only required to handle a split extent across leaf blocks. How to ------- +~~~~~~ Creating Filesystems with Atomic Write Support -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ First check the atomic write units supported by block device. See :ref:`atomic_write_bdev_support` for more details. @@ -176,7 +176,7 @@ Where ``-b`` specifies the block size, ``-C`` specifies the cluster size in byte and ``-O bigalloc`` enables the bigalloc feature. Application Interface -~~~~~~~~~~~~~~~~~~~~~ +^^^^^^^^^^^^^^^^^^^^^ Applications can use the ``pwritev2()`` system call with the ``RWF_ATOMIC`` flag to perform atomic writes: @@ -204,7 +204,7 @@ writes are supported. .. _atomic_write_bdev_support: Hardware Support ----------------- +~~~~~~~~~~~~~~~~ The underlying storage device must support atomic write operations. Modern NVMe and SCSI devices often provide this capability. @@ -217,7 +217,7 @@ Nonzero values for these attributes indicate that the device supports atomic writes. See Also --------- +~~~~~~~~ * :doc:`bigalloc` - Documentation on the bigalloc feature * :doc:`allocators` - Documentation on block allocation in ext4 diff --git a/Documentation/filesystems/ext4/bitmaps.rst b/Documentation/filesystems/ext4/bitmaps.rst index 91c45d86e9bb..9d7d7b083a25 100644 --- a/Documentation/filesystems/ext4/bitmaps.rst +++ b/Documentation/filesystems/ext4/bitmaps.rst @@ -19,10 +19,3 @@ necessarily the case that no blocks are in use -- if ``meta_bg`` is set, the bitmaps and group descriptor live inside the group. Unfortunately, ext2fs_test_block_bitmap2() will return '0' for those locations, which produces confusing debugfs output. - -Inode Table ------------ -Inode tables are statically allocated at mkfs time. Each block group -descriptor points to the start of the table, and the superblock records -the number of inodes per group. See the section on inodes for more -information. diff --git a/Documentation/filesystems/ext4/blockgroup.rst b/Documentation/filesystems/ext4/blockgroup.rst index ed5a5cac6d40..7cbf0b2b778e 100644 --- a/Documentation/filesystems/ext4/blockgroup.rst +++ b/Documentation/filesystems/ext4/blockgroup.rst @@ -1,7 +1,10 @@ .. SPDX-License-Identifier: GPL-2.0 +Block Groups +------------ + Layout ------- +~~~~~~ The layout of a standard block group is approximately as follows (each of these fields is discussed in a separate section below): @@ -60,7 +63,7 @@ groups (flex_bg). Leftover space is used for file data blocks, indirect block maps, extent tree blocks, and extended attributes. Flexible Block Groups ---------------------- +~~~~~~~~~~~~~~~~~~~~~ Starting in ext4, there is a new feature called flexible block groups (flex_bg). In a flex_bg, several block groups are tied together as one @@ -78,7 +81,7 @@ if flex_bg is enabled. The number of block groups that make up a flex_bg is given by 2 ^ ``sb.s_log_groups_per_flex``. Meta Block Groups ------------------ +~~~~~~~~~~~~~~~~~ Without the option META_BG, for safety concerns, all block group descriptors copies are kept in the first block group. Given the default @@ -117,7 +120,7 @@ Please see an important note about ``BLOCK_UNINIT`` in the section about block and inode bitmaps. Lazy Block Group Initialization -------------------------------- +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A new feature for ext4 are three block group descriptor flags that enable mkfs to skip initializing other parts of the block group diff --git a/Documentation/filesystems/ext4/dynamic.rst b/Documentation/filesystems/ext4/dynamic.rst index bb0c84333341..bbad439aada2 100644 --- a/Documentation/filesystems/ext4/dynamic.rst +++ b/Documentation/filesystems/ext4/dynamic.rst @@ -6,7 +6,9 @@ Dynamic Structures Dynamic metadata are created on the fly when files and blocks are allocated to files. -.. include:: inodes.rst -.. include:: ifork.rst -.. include:: directory.rst -.. include:: attributes.rst +.. toctree:: + + inodes + ifork + directory + attributes diff --git a/Documentation/filesystems/ext4/globals.rst b/Documentation/filesystems/ext4/globals.rst index b17418974fd3..c6a6abce818a 100644 --- a/Documentation/filesystems/ext4/globals.rst +++ b/Documentation/filesystems/ext4/globals.rst @@ -6,9 +6,12 @@ Global Structures The filesystem is sharded into a number of block groups, each of which have static metadata at fixed locations. -.. include:: super.rst -.. include:: group_descr.rst -.. include:: bitmaps.rst -.. include:: mmp.rst -.. include:: journal.rst -.. include:: orphan.rst +.. toctree:: + + super + group_descr + bitmaps + inode_table + mmp + journal + orphan diff --git a/Documentation/filesystems/ext4/index.rst b/Documentation/filesystems/ext4/index.rst index 705d813d558f..1ff8150c50e9 100644 --- a/Documentation/filesystems/ext4/index.rst +++ b/Documentation/filesystems/ext4/index.rst @@ -5,7 +5,7 @@ ext4 Data Structures and Algorithms =================================== .. toctree:: - :maxdepth: 6 + :maxdepth: 2 :numbered: about diff --git a/Documentation/filesystems/ext4/inode_table.rst b/Documentation/filesystems/ext4/inode_table.rst new file mode 100644 index 000000000000..f7900a52c0d5 --- /dev/null +++ b/Documentation/filesystems/ext4/inode_table.rst @@ -0,0 +1,9 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Inode Table +----------- + +Inode tables are statically allocated at mkfs time. Each block group +descriptor points to the start of the table, and the superblock records +the number of inodes per group. See :doc:`inode documentation <inodes>` +for more information on inode table layout. diff --git a/Documentation/filesystems/ext4/overview.rst b/Documentation/filesystems/ext4/overview.rst index 9d4054c17ecb..171c3963d7f6 100644 --- a/Documentation/filesystems/ext4/overview.rst +++ b/Documentation/filesystems/ext4/overview.rst @@ -16,13 +16,15 @@ All fields in ext4 are written to disk in little-endian order. HOWEVER, all fields in jbd2 (the journal) are written to disk in big-endian order. -.. include:: blocks.rst -.. include:: blockgroup.rst -.. include:: special_inodes.rst -.. include:: allocators.rst -.. include:: checksums.rst -.. include:: bigalloc.rst -.. include:: inlinedata.rst -.. include:: eainode.rst -.. include:: verity.rst -.. include:: atomic_writes.rst +.. toctree:: + + blocks + blockgroup + special_inodes + allocators + checksums + bigalloc + inlinedata + eainode + verity + atomic_writes |