Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 27 insertions, 0 deletions

diff --git a/Documentation/filesystems/ext4/overview.rst b/Documentation/filesystems/ext4/overview.rst
new file mode 100644
index 000000000..0fad6eda6
--- /dev/null
+++ b/Documentation/filesystems/ext4/overview.rst
@@ -0,0 +1,27 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+High Level Design
+=================
+
+An ext4 file system is split into a series of block groups. To reduce
+performance difficulties due to fragmentation, the block allocator tries
+very hard to keep each file's blocks within the same group, thereby
+reducing seek times. The size of a block group is specified in
+``sb.s_blocks_per_group`` blocks, though it can also calculated as 8 *
+``block_size_in_bytes``. With the default block size of 4KiB, each group
+will contain 32,768 blocks, for a length of 128MiB. The number of block
+groups is the size of the device divided by the size of a block group.
+
+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