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author | Jason Gunthorpe <jgg@mellanox.com> | 2018-08-16 22:13:03 +0200 |
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committer | Jason Gunthorpe <jgg@mellanox.com> | 2018-08-16 22:21:29 +0200 |
commit | 0a3173a5f09bc58a3638ecfd0a80bdbae55e123c (patch) | |
tree | d6c0bc84863cca54dfbde3b7463e5d49c82af9f1 /Documentation/filesystems/ext4/ondisk/overview.rst | |
parent | Revert "net/smc: Replace ib_query_gid with rdma_get_gid_attr" (diff) | |
parent | Merge tag 'for-linus-4.19-ofs1' of git://git.kernel.org/pub/scm/linux/kernel/... (diff) | |
download | linux-0a3173a5f09bc58a3638ecfd0a80bdbae55e123c.tar.xz linux-0a3173a5f09bc58a3638ecfd0a80bdbae55e123c.zip |
Merge branch 'linus/master' into rdma.git for-next
rdma.git merge resolution for the 4.19 merge window
Conflicts:
drivers/infiniband/core/rdma_core.c
- Use the rdma code and revise with the new spelling for
atomic_fetch_add_unless
drivers/nvme/host/rdma.c
- Replace max_sge with max_send_sge in new blk code
drivers/nvme/target/rdma.c
- Use the blk code and revise to use NULL for ib_post_recv when
appropriate
- Replace max_sge with max_recv_sge in new blk code
net/rds/ib_send.c
- Use the net code and revise to use NULL for ib_post_recv when
appropriate
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'Documentation/filesystems/ext4/ondisk/overview.rst')
-rw-r--r-- | Documentation/filesystems/ext4/ondisk/overview.rst | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/filesystems/ext4/ondisk/overview.rst b/Documentation/filesystems/ext4/ondisk/overview.rst new file mode 100644 index 000000000000..cbab18baba12 --- /dev/null +++ b/Documentation/filesystems/ext4/ondisk/overview.rst @@ -0,0 +1,26 @@ +.. 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 |