# SPDX-License-Identifier: GPL-2.0
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config EROFS_FS
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tristate "EROFS filesystem support"
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depends on BLOCK
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help
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EROFS(Enhanced Read-Only File System) is a lightweight
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read-only file system with modern designs (eg. page-sized
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blocks, inline xattrs/data, etc.) for scenarios which need
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high-performance read-only requirements, eg. firmwares in
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mobile phone or LIVECDs.
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It also provides VLE compression support, focusing on
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random read improvements, keeping relatively lower
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compression ratios, which is useful for high-performance
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devices with limited memory and ROM space.
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If unsure, say N.
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config EROFS_FS_DEBUG
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bool "EROFS debugging feature"
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depends on EROFS_FS
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help
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Print EROFS debugging messages and enable more BUG_ONs
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which check the filesystem consistency aggressively.
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For daily use, say N.
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config EROFS_FS_XATTR
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bool "EROFS extended attributes"
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depends on EROFS_FS
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default y
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help
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Extended attributes are name:value pairs associated with inodes by
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the kernel or by users (see the attr(5) manual page, or visit
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<http://acl.bestbits.at/> for details).
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If unsure, say N.
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config EROFS_FS_POSIX_ACL
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bool "EROFS Access Control Lists"
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depends on EROFS_FS_XATTR
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select FS_POSIX_ACL
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default y
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help
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Posix Access Control Lists (ACLs) support permissions for users and
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groups beyond the owner/group/world scheme.
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To learn more about Access Control Lists, visit the POSIX ACLs for
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Linux website <http://acl.bestbits.at/>.
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If you don't know what Access Control Lists are, say N.
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config EROFS_FS_SECURITY
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bool "EROFS Security Labels"
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depends on EROFS_FS_XATTR
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help
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Security labels provide an access control facility to support Linux
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Security Models (LSMs) accepted by AppArmor, SELinux, Smack and TOMOYO
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Linux. This option enables an extended attribute handler for file
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security labels in the erofs filesystem, so that it requires enabling
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the extended attribute support in advance.
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If you are not using a security module, say N.
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config EROFS_FS_USE_VM_MAP_RAM
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bool "EROFS VM_MAP_RAM Support"
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depends on EROFS_FS
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help
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use vm_map_ram/vm_unmap_ram instead of vmap/vunmap.
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If you don't know what these are, say N.
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config EROFS_FAULT_INJECTION
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bool "EROFS fault injection facility"
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depends on EROFS_FS
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help
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Test EROFS to inject faults such as ENOMEM, EIO, and so on.
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If unsure, say N.
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config EROFS_FS_ZIP
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bool "EROFS Data Compresssion Support"
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depends on EROFS_FS
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help
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Currently we support VLE Compression only.
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Play at your own risk.
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If you don't want to use compression feature, say N.
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config EROFS_FS_CLUSTER_PAGE_LIMIT
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int "EROFS Cluster Pages Hard Limit"
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depends on EROFS_FS_ZIP
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range 1 256
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default "1"
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help
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Indicates VLE compressed pages hard limit of a
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compressed cluster.
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For example, if files of a image are compressed
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into 8k-unit, the hard limit should not be less
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than 2. Otherwise, the image cannot be mounted
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correctly on this kernel.
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choice
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prompt "EROFS VLE Data Decompression mode"
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depends on EROFS_FS_ZIP
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default EROFS_FS_ZIP_CACHE_BIPOLAR
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help
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EROFS supports three options for VLE decompression.
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"In-place Decompression Only" consumes the minimum memory
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with lowest random read.
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"Bipolar Cached Decompression" consumes the maximum memory
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with highest random read.
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If unsure, select "Bipolar Cached Decompression"
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config EROFS_FS_ZIP_NO_CACHE
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bool "In-place Decompression Only"
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help
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Read compressed data into page cache and do in-place
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decompression directly.
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config EROFS_FS_ZIP_CACHE_UNIPOLAR
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bool "Unipolar Cached Decompression"
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help
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For each request, it caches the last compressed page
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for further reading.
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It still decompresses in place for the rest compressed pages.
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config EROFS_FS_ZIP_CACHE_BIPOLAR
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bool "Bipolar Cached Decompression"
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help
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For each request, it caches the both end compressed pages
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for further reading.
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It still decompresses in place for the rest compressed pages.
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Recommended for performance priority.
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endchoice
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