1mount.composefs(1)               User Commands              mount.composefs(1)
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NAME

6       mount.composefs - mount a composefs filesystem image
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SYNOPSIS

9       mount.composefs [-o OPTIONS] IMAGE TARGETDIR
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DESCRIPTION

12       The  composefs project uses EROFS image file to store metadata, and one
13       or more separate directories containing content-addressed backing  data
14       for regular files.
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16       mount.composefs  mounts  such an EROFS file in combination with a given
17       set of basedir at the specified location.  It can be  called  directly,
18       or as a mount helper by running mount -t composefst ....
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OPTIONS

21       The  provided IMAGE argument must be a valid composefs (EROFS) metadata
22       image.  The TARGETDIR will be used as a mount target.
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24       mount.composefs accepts the  following  colon-separated  mount  options
25       when passed via the -o OPTIONS argument.
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27       basedir=PATH
28              This  path  will  be  used  to resolve non-empty file references
29              stored in the composefs metadata image.  A primary use  case  is
30              to  have this be the same path provided to mkcomposefs --digest-
31              store=PATH.
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33              Multiple paths can be specified, separated by :.
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35       digest=DIGEST
36              The image file is validated to have the specified fs-verity  di‐
37              gest  before  being  used.  This allows a chain of trust the en‐
38              sures only the expected data is ever visible in the mount.
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40              This option also implies verity.
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42       verity If this is specified, all files in the IMAGE must specify an fs-
43              verity  digest,  and  all the files in the base dirs must have a
44              matching fs-verity digest.
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46              Note: This needs support for the overlayfs  “verity”  option  in
47              the kernel, which was added in 6.6rc1.
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49       ro     Mounts the filesystem read-only.  This is mainly useful when us‐
50              ing upperdir as unlayered composefs images are naturally readon‐
51              ly.
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53       rw     Overrides a previous ro option
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55       upperdir
56              Specify an upper dir in the overlayfs mount that composefs uses.
57              This allows a writable layer on top of the composefs image.  See
58              overlayfs docs for details.
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60       workdir
61              Specifies an overlayfs workdir to go with upperdir.
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SEE ALSO

64       composefs-info(1), mount.composefs(1)
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66       composefs upstream (https://github.com/containers/composefs)
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70composefs                                                   mount.composefs(1)
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