Add support for ramfs as well as tmpfs in volume mounts

Fixes: containers#19659

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

docs/source/markdown/options/mount.md

@@ -6,25 +6,26 @@
 
 Attach a filesystem mount to the container
 
-Current supported mount TYPEs are **bind**, **devpts**, **glob**, **image**, **tmpfs** and **volume**. <sup>[[1]](#Footnote1)</sup>
+Current supported mount TYPEs are **bind**, **devpts**, **glob**, **image**, **ramfs**, **tmpfs** and **volume**. <sup>[[1]](#Footnote1)</sup>
 
        e.g.
-
        type=bind,source=/path/on/host,destination=/path/in/container
 
        type=bind,src=/path/on/host,dst=/path/in/container,relabel=shared
 
        type=bind,src=/path/on/host,dst=/path/in/container,relabel=shared,U=true
 
+       type=devpts,destination=/dev/pts
+
        type=glob,src=/usr/lib/libfoo*,destination=/usr/lib,ro=true
 
-       type=volume,source=vol1,destination=/path/in/container,ro=true
+       type=image,source=fedora,destination=/fedora-image,rw=true
 
-       type=tmpfs,tmpfs-size=512M,destination=/path/in/container
+       type=ramfs,tmpfs-size=512M,destination=/path/in/container
 
-       type=image,source=fedora,destination=/fedora-image,rw=true
+       type=tmpfs,tmpfs-size=512M,destination=/path/in/container
 
-       type=devpts,destination=/dev/pts
+       type=volume,source=vol1,destination=/path/in/container,ro=true
 
        Common Options:
 
@@ -72,17 +73,17 @@ Current supported mount TYPEs are **bind**, **devpts**, **glob**, **image**, **t
 
 	      . U, chown: true or false (default). Change recursively the owner and group of the source volume based on the UID and GID of the container.
 
-       Options specific to tmpfs:
+       Options specific to tmpfs and ramfs:
 
 	      · ro, readonly: true or false (default).
 
-	      · tmpfs-size: Size of the tmpfs mount in bytes. Unlimited by default in Linux.
+	      · tmpfs-size: Size of the tmpfs/ramfs mount in bytes. Unlimited by default in Linux.
 
-	      · tmpfs-mode: File mode of the tmpfs in octal. (e.g. 700 or 0700.) Defaults to 1777 in Linux.
+	      · tmpfs-mode: File mode of the tmpfs/ramfs in octal. (e.g. 700 or 0700.) Defaults to 1777 in Linux.
 
-	      · tmpcopyup: Enable copyup from the image directory at the same location to the tmpfs. Used by default.
+	      · tmpcopyup: Enable copyup from the image directory at the same location to the tmpfs/ramfs. Used by default.
 
-	      · notmpcopyup: Disable copying files from the image to the tmpfs.
+	      · notmpcopyup: Disable copying files from the image to the tmpfs/ramfs.
 
 	      . U, chown: true or false (default). Change recursively the owner and group of the source volume based on the UID and GID of the container.
 

libpod/define/mount.go

@@ -1,10 +1,12 @@
 package define
 
 const (
-	// TypeVolume is the type for named volumes
-	TypeVolume = "volume"
-	// TypeTmpfs is the type for mounting tmpfs
-	TypeTmpfs = "tmpfs"
 	// TypeDevpts is the type for creating a devpts
 	TypeDevpts = "devpts"
+	// TypeTmpfs is the type for mounting tmpfs
+	TypeTmpfs = "tmpfs"
+	// TypeRamfs is the type for mounting ramfs
+	TypeRamfs = "ramfs"
+	// TypeVolume is the type for named volumes
+	TypeVolume = "volume"
 )

pkg/specgenutil/volumes.go

@@ -211,8 +211,8 @@ func Mounts(mountFlag []string, configMounts []string) (map[string]spec.Mount, m
 					}
 					finalMounts[mount.Destination] = mount
 				}
-			case define.TypeTmpfs:
-				mount, err := getTmpfsMount(tokens)
+			case define.TypeTmpfs, define.TypeRamfs:
+				mount, err := getTmpfsMount(tokens, mountType)
 				if err != nil {
 					return err
 				}
@@ -525,11 +525,11 @@ func getBindMount(args []string) (spec.Mount, error) {
 	return newMount, nil
 }
 
-// Parse a single tmpfs mount entry from the --mount flag
-func getTmpfsMount(args []string) (spec.Mount, error) {
+// Parse a single tmpfs/ramfs mount entry from the --mount flag
+func getTmpfsMount(args []string, tmpfsType string) (spec.Mount, error) {
 	newMount := spec.Mount{
-		Type:   define.TypeTmpfs,
-		Source: define.TypeTmpfs,
+		Type:   tmpfsType,
+		Source: tmpfsType,
 	}
 
 	var err error

test/system/060-mount.bats

@@ -294,4 +294,10 @@ EOF
     is "$output" "bar1.*bar2.*bar3" "Should match multiple source files on single destination directory"
 }
 
+@test "podman mount ramfs" {
+    # if volumes source and dest match then pass
+    run_podman run --rm --mount type=ramfs,destination=${PODMAN_TMPDIR} $IMAGE stat -f -c "%T" ${PODMAN_TMPDIR}
+    is "$output" "ramfs" "ramfs mounted"
+}
+
 # vim: filetype=sh