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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/blocks.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/blocks.rst')
-rw-r--r-- | Documentation/filesystems/ext4/ondisk/blocks.rst | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/Documentation/filesystems/ext4/ondisk/blocks.rst b/Documentation/filesystems/ext4/ondisk/blocks.rst new file mode 100644 index 000000000000..73d4dc0f7bda --- /dev/null +++ b/Documentation/filesystems/ext4/ondisk/blocks.rst @@ -0,0 +1,142 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Blocks +------ + +ext4 allocates storage space in units of “blocks”. A block is a group of +sectors between 1KiB and 64KiB, and the number of sectors must be an +integral power of 2. Blocks are in turn grouped into larger units called +block groups. Block size is specified at mkfs time and typically is +4KiB. You may experience mounting problems if block size is greater than +page size (i.e. 64KiB blocks on a i386 which only has 4KiB memory +pages). By default a filesystem can contain 2^32 blocks; if the '64bit' +feature is enabled, then a filesystem can have 2^64 blocks. + +For 32-bit filesystems, limits are as follows: + +.. list-table:: + :widths: 1 1 1 1 1 + :header-rows: 1 + + * - Item + - 1KiB + - 2KiB + - 4KiB + - 64KiB + * - Blocks + - 2^32 + - 2^32 + - 2^32 + - 2^32 + * - Inodes + - 2^32 + - 2^32 + - 2^32 + - 2^32 + * - File System Size + - 4TiB + - 8TiB + - 16TiB + - 256PiB + * - Blocks Per Block Group + - 8,192 + - 16,384 + - 32,768 + - 524,288 + * - Inodes Per Block Group + - 8,192 + - 16,384 + - 32,768 + - 524,288 + * - Block Group Size + - 8MiB + - 32MiB + - 128MiB + - 32GiB + * - Blocks Per File, Extents + - 2^32 + - 2^32 + - 2^32 + - 2^32 + * - Blocks Per File, Block Maps + - 16,843,020 + - 134,480,396 + - 1,074,791,436 + - 4,398,314,962,956 (really 2^32 due to field size limitations) + * - File Size, Extents + - 4TiB + - 8TiB + - 16TiB + - 256TiB + * - File Size, Block Maps + - 16GiB + - 256GiB + - 4TiB + - 256TiB + +For 64-bit filesystems, limits are as follows: + +.. list-table:: + :widths: 1 1 1 1 1 + :header-rows: 1 + + * - Item + - 1KiB + - 2KiB + - 4KiB + - 64KiB + * - Blocks + - 2^64 + - 2^64 + - 2^64 + - 2^64 + * - Inodes + - 2^32 + - 2^32 + - 2^32 + - 2^32 + * - File System Size + - 16ZiB + - 32ZiB + - 64ZiB + - 1YiB + * - Blocks Per Block Group + - 8,192 + - 16,384 + - 32,768 + - 524,288 + * - Inodes Per Block Group + - 8,192 + - 16,384 + - 32,768 + - 524,288 + * - Block Group Size + - 8MiB + - 32MiB + - 128MiB + - 32GiB + * - Blocks Per File, Extents + - 2^32 + - 2^32 + - 2^32 + - 2^32 + * - Blocks Per File, Block Maps + - 16,843,020 + - 134,480,396 + - 1,074,791,436 + - 4,398,314,962,956 (really 2^32 due to field size limitations) + * - File Size, Extents + - 4TiB + - 8TiB + - 16TiB + - 256TiB + * - File Size, Block Maps + - 16GiB + - 256GiB + - 4TiB + - 256TiB + +Note: Files not using extents (i.e. files using block maps) must be +placed within the first 2^32 blocks of a filesystem. Files with extents +must be placed within the first 2^48 blocks of a filesystem. It's not +clear what happens with larger filesystems. |