Add new configuration for devicemapper support in containers/storage

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

storage.conf

@@ -1,7 +1,6 @@
 # storage.conf is the configuration file for all tools
 # that share the containers/storage libraries
 # See man 5 containers-storage.conf for more information
-
 # The "container storage" table contains all of the server options.
 [storage]
 
@@ -15,6 +14,8 @@ runroot = "/var/run/containers/storage"
 graphroot = "/var/lib/containers/storage"
 
 [storage.options]
+# Storage options to be passed to underlying storage drivers
+
 # AdditionalImageStores is used to pass paths to additional Read/Only image stores
 # Must be comma separated list.
 additionalimagestores = [
@@ -26,3 +27,88 @@ size = ""
 
 # OverrideKernelCheck tells the driver to ignore kernel checks based on kernel version
 override_kernel_check = "true"
+
+# Remap-UIDs/GIDs is the mapping from UIDs/GIDs as they should appear inside of
+# a container, to UIDs/GIDs as they should appear outside of the container, and
+# the length of the range of UIDs/GIDs.  Additional mapped sets can be listed
+# and will be heeded by libraries, but there are limits to the number of
+# mappings which the kernel will allow when you later attempt to run a
+# container.
+#
+# remap-uids = 0:1668442479:65536
+# remap-gids = 0:1668442479:65536
+
+# Remap-User/Group is a name which can be used to look up one or more UID/GID
+# ranges in the /etc/subuid or /etc/subgid file.  Mappings are set up starting
+# with an in-container ID of 0 and the a host-level ID taken from the lowest
+# range that matches the specified name, and using the length of that range.
+# Additional ranges are then assigned, using the ranges which specify the
+# lowest host-level IDs first, to the lowest not-yet-mapped container-level ID,
+# until all of the entries have been used for maps.
+#
+# remap-user = "storage"
+# remap-group = "storage"
+
+[storage.options.thinpool]
+# Storage Options for thinpool
+
+# autoextend_percent determines the amount by which pool needs to be
+# grown. This is specified in terms of % of pool size. So a value of 20 means
+# that when threshold is hit, pool will be grown by 20% of existing
+# pool size.
+# autoextend_percent = "20"
+
+# autoextend_threshold determines the pool extension threshold in terms
+# of percentage of pool size. For example, if threshold is 60, that means when
+# pool is 60% full, threshold has been hit.
+# autoextend_threshold = "80"
+
+# basesize specifies the size to use when creating the base device, which
+# limits the size of images and containers.
+# basesize = "10G"
+
+# blocksize specifies a custom blocksize to use for the thin pool.
+# blocksize="64k"
+
+# directlvm_device specifies a custom block storage device to use for the
+# thin pool. Required if you setup devicemapper
+# directlvm_device = ""
+
+# directlvm_device_force wipes device even if device already has a filesystem
+# directlvm_device_force = "True"
+
+# fs specifies the filesystem type to use for the base device.
+# fs="xfs"
+
+# log_level sets the log level of devicemapper.
+# 0: LogLevelSuppress 0 (Default)
+# 2: LogLevelFatal
+# 3: LogLevelErr
+# 4: LogLevelWarn
+# 5: LogLevelNotice
+# 6: LogLevelInfo
+# 7: LogLevelDebug
+# log_level = "7"
+
+# min_free_space specifies the min free space percent in a thin pool require for
+# new device creation to succeed. Valid values are from 0% - 99%.
+# Value 0% disables
+# min_free_space = "10%"
+
+# mkfsarg specifies extra mkfs arguments to be used when creating the base
+# device.
+# mkfsarg = ""
+
+# mountopt specifies extra mount options used when mounting the thin devices.
+# mountopt = ""
+
+# use_deferred_removal Marking device for deferred removal
+# use_deferred_removal = "True"
+
+# use_deferred_deletion Marking device for deferred deletion
+# use_deferred_deletion = "True"
+
+# xfs_nospace_max_retries specifies the maximum number of retries XFS should
+# attempt to complete IO when ENOSPC (no space) error is returned by
+# underlying storage device.
+# xfs_nospace_max_retries = "0"