'\" t
.TH "SYSTEMD\-STORAGE\-FS@\&.SERVICE" "8" "" "systemd 261.1" "systemd-storage-fs@.service"
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.SH "NAME"
systemd-storage-fs@.service, systemd-storage-fs.socket, systemd-storage-fs \- Storage provider exposing regular files and directories as storage volumes
.SH "SYNOPSIS"
.PP
systemd\-storage\-fs@\&.service
.PP
systemd\-storage\-fs\&.socket
.SH "DESCRIPTION"
.PP
systemd\-storage\-fs@\&.service
is a service that implements the
\fBio\&.systemd\&.StorageProvider\fR
\m[blue]\fBVarlink\fR\m[]\&\s-2\u[1]\d\s+2
interface, exposing regular files and directories in
/var/lib/storage/*\&.volume
(if used in system mode) or
$XDG_STATE_HOME/storage
(when used in user mode) as storage volumes\&. Acquired volumes are returned to the caller as file descriptors\&. Unlike
\fBsystemd-storage-block@.service\fR(8), this implementation also supports creating new volumes on demand from a small set of built\-in templates\&.
.PP
The service is socket\-activated via
systemd\-storage\-fs\&.socket\&. In system mode it listens on the AF_UNIX socket
/run/systemd/io\&.systemd\&.StorageProvider/fs, in user mode on
$XDG_RUNTIME_DIR/systemd/io\&.systemd\&.StorageProvider/fs\&. See
\fBstoragectl\fR(1)
for an enumeration tool\&.
.PP
See also
\fBsystemd-storage-block@.service\fR(8)
for a complementary implementation that exposes local block devices as storage volumes\&.
.SH "VOLUMES"
.PP
Volumes are stored below the storage directory:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
/var/lib/storage/
when run in system mode\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
$XDG_STATE_HOME/storage/
(typically
~/\&.local/state/storage/) when run in user mode\&.
.RE
.PP
Each volume on disk is stored as a directory entry with a
\&.volume
suffix in the storage directory\&. Entries which are regular files are exposed as volumes of type
\fBreg\fR; entries which are directories are exposed as volumes of type
\fBdir\fR\&. Moreover, block device nodes may be symlinked (or bind mounted) into the directory, which are then exposed as volumes of type
\fBblk\fR\&.
.PP
For directory volumes, the root of the file system passed to clients is placed in a subdirectory
root/
of the
\fINAME\fR\&.volume
directory\&. The former (and all inodes below it) must be owned by the foreign UID range, the latter by the host\*(Aqs root\&.
.PP
When acquiring a volume, symlinks are followed\&.
.PP
An administrator is permitted to freely manipulate the volume hierarchy directly as long as the rules described above are followed\&. In particular, it\*(Aqs permitted to copy, mount or symlink arbitrary external resources (regardless if directory, regular file or block) into the volume directory, so that they are exposed as additional volumes\&.
.SH "TEMPLATES"
.PP
The provider supports creating new volumes automatically when they are acquired\&. The caller may select a
\fItemplate\fR
that determines configuration details of the volume to create\&. The following built\-in templates are available:
.PP
\fBsparse\-file\fR
.RS 4
Creates a volume backed by a sparsely populated regular file\&. This is the default template when creating a regular file volume\&. (Volume type is
"reg"\&.)
.sp
Added in version 261\&.
.RE
.PP
\fBallocated\-file\fR
.RS 4
Creates a volume backed by a fully allocated regular file\&. (Volume type is
"reg"\&.)
.sp
Added in version 261\&.
.RE
.PP
\fBdirectory\fR
.RS 4
Creates a volume backed by a regular directory\&. (Volume type is
"dir"\&.)
.sp
Added in version 261\&.
.RE
.PP
\fBsubvolume\fR
.RS 4
Creates a btrfs subvolume as backing inode (falling back to a regular directory if the storage directory is not on btrfs)\&. This is the default template when creating a directory volume\&. (Volume type is
"dir"\&.)
.sp
Added in version 261\&.
.RE
.SH "OPTIONS"
.PP
The following command\-line options are understood:
.PP
\fB\-\-system\fR
.RS 4
Operate in system mode\&. Volumes are stored below
/var/lib/storage/\&. This is the default when invoked from
systemd\-storage\-fs@\&.service
in the system manager\&.
.sp
Added in version 261\&.
.RE
.PP
\fB\-\-user\fR
.RS 4
Operate in user mode\&. Volumes are stored below
$XDG_STATE_HOME/storage/\&. This is the default when invoked from
systemd\-storage\-fs@\&.service
in the user manager\&.
.sp
Added in version 261\&.
.RE
.PP
\fB\-h\fR, \fB\-\-help\fR
.RS 4
Print a short help text and exit\&.
.RE
.PP
\fB\-\-version\fR
.RS 4
Print a short version string and exit\&.
.RE
.SH "FILES"
.PP
/var/lib/storage/, $XDG_STATE_HOME/storage/
.RS 4
The storage directory used to back the system mode and user mode service instances respectively\&. Each volume is stored as an entry with a
\&.volume
suffix below this directory\&.
.sp
Added in version 261\&.
.RE
.PP
/run/systemd/io\&.systemd\&.StorageProvider/fs, $XDG_RUNTIME_DIR/systemd/io\&.systemd\&.StorageProvider/fs
.RS 4
AF_UNIX sockets the service listens on, in system and user mode respectively\&. These are the canonical locations for the
"fs"
storage provider, and are enumerated by
\fBstoragectl providers\fR\&.
.sp
Added in version 261\&.
.RE
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1), \fBstoragectl\fR(1), \fBsystemd-storage-block@.service\fR(8)
.SH "NOTES"
.IP " 1." 4
Varlink
.RS 4
\%https://varlink.org/
.RE