diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/index.rst | 1 | ||||
| -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 |