erofs - the Enhanced Read-Only File System

NAME DESCRIPTION Mount options VERSIONS CONFIGURATION SEE ALSO

NAME

erofs − the Enhanced Read-Only File System

DESCRIPTION

erofs is a create-once read-only filesystem, with support for compression and a multi-device backing store.

There are two inode formats:

	•		32-byte compact with 16-bit UID/GID, 32-bit file size, and no file times
	•		64-byte extended with 32-bit UID/GID, 64-bit file size, and a modification time (st_mtim).

Mount options

user_xattr
nouser_xattr

Controls whether user extended attributes are exposed. Defaults to yes.

	acl
	noacl		Controls whether POSIX acl(5)s are exposed. Defaults to yes.

cache_strategy=disabled|readahead|readaround

Cache allocation for compressed files: never, if reading from start of file, regardless of position. Defaults to readaround.

dax

dax=always|never

Direct Access control. If always and the source device supports DAX, uncompressed non-inlined files will be read directly, without going through the page cache. dax is a synonym for always. Defaults to unset, which is equivalent to never.

device=blobdev

Add extra device holding some of the data. Must be given as many times and in the same order as −−blobdev was to mkfs.erofs(1).

domain_id=did
fsid=id

Control CacheFiles on-demand read support. To be documented.

VERSIONS

erofs images are versioned through the use of feature flags; these are listed in the −E section of mkfs.erofs(1),

CONFIGURATION

Linux must be configured with the CONFIG_EROFS_FS option to mount EROFS filesystems. There are sub-configuration items that restrict the availability of some of the parameters above.