erofs - Man Page
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.
See Also
mkfs.erofs(1), fsck.erofs(1), dump.erofs(1)
Documentation/filesystems/erofs.txt in the Linux source.