erofs(5) File Formats Manual erofs(5)
NAME
erofs - the Enhanced Read-Only File System
DESCRIPTION
erofs is a create-once read-only filesystem, with support for compres-
sion 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 modi-
fication 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, with-
out 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.
Linux man-pages 6.7 2023-10-31 erofs(5)
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