mount.composefs(1)(composefs)      Commands      mount.composefs(1)(composefs)



NAME
       mount.composefs - mount a composefs filesystem image



SYNOPSIS
       mount.composefs [-o OPTIONS] IMAGE TARGETDIR



DESCRIPTION
       The composefs project uses EROFS image file to store metadata, and one
       or more separate directories containing content-addressed backing data
       for regular files.


       mount.composefs mounts such an EROFS file in combination with a given
       set of basedir at the specified location. It can be called directly, or
       as a mount helper by running mount -t composefs ....



OPTIONS
       The provided IMAGE argument must be a valid composefs (EROFS) metadata
       image.  The TARGETDIR will be used as a mount target.


       mount.composefs accepts the following colon-separated mount options
       when passed via the -o OPTIONS argument.

       basedir=PATH
              This path will be used to resolve non-empty file references
              stored in the composefs metadata image.  A primary use case is
              to have this be the same path provided to mkcomposefs --digest-
              store=PATH.

              Multiple paths can be specified, separated by :.


       digest=DIGEST
              The image file is validated to have the specified fs-verity
              digest before being used. This allows a chain of trust the
              ensures only the expected data is ever visible in the mount.

              This option also implies verity.


       idmap=PATH
              Specify a path to a user namespace whose ID mapping should be
              used.  The typical format for this type of path is
              /proc/<pid>/ns/user


       verity If this is specified, all files in the IMAGE must specify an fs-
              verity digest, and all the files in the base dirs must have a
              matching fs-verity digest.

              Note: This needs support for the overlayfs "verity" option in
              the kernel, which was added in 6.6rc1.


       ro     Mounts the filesystem read-only. This is mainly useful when
              using upperdir as unlayered composefs images are naturally
              readonly.


       rw     Overrides a previous ro option


       upperdir
              Specify an upper dir in the overlayfs mount that composefs uses.
              This allows a writable layer on top of the composefs image. See
              overlayfs docs for details.


       workdir
              Specifies an overlayfs workdir to go with upperdir.



SEE ALSO
       composefs-info(1), mount.composefs(1)


       composefs upstream <https://github.com/containers/composefs>

User                                   |         mount.composefs(1)(composefs)