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-rw-r--r--Documentation/filesystems/index.rst1
-rw-r--r--Documentation/filesystems/zonefs.rst (renamed from Documentation/filesystems/zonefs.txt)108
2 files changed, 59 insertions, 50 deletions
diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst
index ec03cb4d7353..53f46a88e6ec 100644
--- a/Documentation/filesystems/index.rst
+++ b/Documentation/filesystems/index.rst
@@ -95,3 +95,4 @@ Documentation for filesystem implementations.
udf
virtiofs
vfat
+ zonefs
diff --git a/Documentation/filesystems/zonefs.txt b/Documentation/filesystems/zonefs.rst
index 935bf22031ca..7e733e751e98 100644
--- a/Documentation/filesystems/zonefs.txt
+++ b/Documentation/filesystems/zonefs.rst
@@ -1,4 +1,8 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+================================================
ZoneFS - Zone filesystem for Zoned block devices
+================================================
Introduction
============
@@ -29,6 +33,7 @@ Zoned block devices
Zoned storage devices belong to a class of storage devices with an address
space that is divided into zones. A zone is a group of consecutive LBAs and all
zones are contiguous (there are no LBA gaps). Zones may have different types.
+
* Conventional zones: there are no access constraints to LBAs belonging to
conventional zones. Any read or write access can be executed, similarly to a
regular block device.
@@ -158,6 +163,7 @@ Format options
--------------
Several optional features of zonefs can be enabled at format time.
+
* Conventional zone aggregation: ranges of contiguous conventional zones can be
aggregated into a single larger file instead of the default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0 (root)
@@ -249,7 +255,7 @@ permissions.
Further action taken by zonefs I/O error recovery can be controlled by the user
with the "errors=xxx" mount option. The table below summarizes the result of
zonefs I/O error processing depending on the mount option and on the zone
-conditions.
+conditions::
+--------------+-----------+-----------------------------------------+
| | | Post error state |
@@ -275,6 +281,7 @@ conditions.
+--------------+-----------+-----------------------------------------+
Further notes:
+
* The "errors=remount-ro" mount option is the default behavior of zonefs I/O
error processing if no errors mount option is specified.
* With the "errors=remount-ro" mount option, the change of the file access
@@ -302,6 +309,7 @@ Mount options
zonefs define the "errors=<behavior>" mount option to allow the user to specify
zonefs behavior in response to I/O errors, inode size inconsistencies or zone
condition chages. The defined behaviors are as follow:
+
* remount-ro (default)
* zone-ro
* zone-offline
@@ -325,78 +333,78 @@ Examples
--------
The following formats a 15TB host-managed SMR HDD with 256 MB zones
-with the conventional zones aggregation feature enabled.
+with the conventional zones aggregation feature enabled::
-# mkzonefs -o aggr_cnv /dev/sdX
-# mount -t zonefs /dev/sdX /mnt
-# ls -l /mnt/
-total 0
-dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
-dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
+ # mkzonefs -o aggr_cnv /dev/sdX
+ # mount -t zonefs /dev/sdX /mnt
+ # ls -l /mnt/
+ total 0
+ dr-xr-xr-x 2 root root 1 Nov 25 13:23 cnv
+ dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq
The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a single
-file).
+file)::
-# ls -l /mnt/cnv
-total 137101312
--rw-r----- 1 root root 140391743488 Nov 25 13:23 0
+ # ls -l /mnt/cnv
+ total 137101312
+ -rw-r----- 1 root root 140391743488 Nov 25 13:23 0
-This aggregated conventional zone file can be used as a regular file.
+This aggregated conventional zone file can be used as a regular file::
-# mkfs.ext4 /mnt/cnv/0
-# mount -o loop /mnt/cnv/0 /data
+ # mkfs.ext4 /mnt/cnv/0
+ # mount -o loop /mnt/cnv/0 /data
The "seq" sub-directory grouping files for sequential write zones has in this
-example 55356 zones.
+example 55356 zones::
-# ls -lv /mnt/seq
-total 14511243264
--rw-r----- 1 root root 0 Nov 25 13:23 0
--rw-r----- 1 root root 0 Nov 25 13:23 1
--rw-r----- 1 root root 0 Nov 25 13:23 2
-...
--rw-r----- 1 root root 0 Nov 25 13:23 55354
--rw-r----- 1 root root 0 Nov 25 13:23 55355
+ # ls -lv /mnt/seq
+ total 14511243264
+ -rw-r----- 1 root root 0 Nov 25 13:23 0
+ -rw-r----- 1 root root 0 Nov 25 13:23 1
+ -rw-r----- 1 root root 0 Nov 25 13:23 2
+ ...
+ -rw-r----- 1 root root 0 Nov 25 13:23 55354
+ -rw-r----- 1 root root 0 Nov 25 13:23 55355
For sequential write zone files, the file size changes as data is appended at
-the end of the file, similarly to any regular file system.
+the end of the file, similarly to any regular file system::
-# dd if=/dev/zero of=/mnt/seq/0 bs=4096 count=1 conv=notrunc oflag=direct
-1+0 records in
-1+0 records out
-4096 bytes (4.1 kB, 4.0 KiB) copied, 0.00044121 s, 9.3 MB/s
+ # dd if=/dev/zero of=/mnt/seq/0 bs=4096 count=1 conv=notrunc oflag=direct
+ 1+0 records in
+ 1+0 records out
+ 4096 bytes (4.1 kB, 4.0 KiB) copied, 0.00044121 s, 9.3 MB/s
-# ls -l /mnt/seq/0
--rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
+ # ls -l /mnt/seq/0
+ -rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0
The written file can be truncated to the zone size, preventing any further
-write operation.
+write operation::
-# truncate -s 268435456 /mnt/seq/0
-# ls -l /mnt/seq/0
--rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
+ # truncate -s 268435456 /mnt/seq/0
+ # ls -l /mnt/seq/0
+ -rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0
Truncation to 0 size allows freeing the file zone storage space and restart
-append-writes to the file.
+append-writes to the file::
-# truncate -s 0 /mnt/seq/0
-# ls -l /mnt/seq/0
--rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
+ # truncate -s 0 /mnt/seq/0
+ # ls -l /mnt/seq/0
+ -rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0
Since files are statically mapped to zones on the disk, the number of blocks of
-a file as reported by stat() and fstat() indicates the size of the file zone.
-
-# stat /mnt/seq/0
- File: /mnt/seq/0
- Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
-Device: 870h/2160d Inode: 50431 Links: 1
-Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
-Access: 2019-11-25 13:23:57.048971997 +0900
-Modify: 2019-11-25 13:52:25.553805765 +0900
-Change: 2019-11-25 13:52:25.553805765 +0900
- Birth: -
+a file as reported by stat() and fstat() indicates the size of the file zone::
+
+ # stat /mnt/seq/0
+ File: /mnt/seq/0
+ Size: 0 Blocks: 524288 IO Block: 4096 regular empty file
+ Device: 870h/2160d Inode: 50431 Links: 1
+ Access: (0640/-rw-r-----) Uid: ( 0/ root) Gid: ( 0/ root)
+ Access: 2019-11-25 13:23:57.048971997 +0900
+ Modify: 2019-11-25 13:52:25.553805765 +0900
+ Change: 2019-11-25 13:52:25.553805765 +0900
+ Birth: -
The number of blocks of the file ("Blocks") in units of 512B blocks gives the
maximum file size of 524288 * 512 B = 256 MB, corresponding to the device zone