ensure workdir and upperdir are on same fs

This redefines the --persist argument to point to a directory where atomfs will create or use both the workdir and the upperdir. So if you run `atomfs mount --persist=foo/` then the persistent writes will end up at foo/persist/. Signed-off-by: Michael McCracken <[email protected]>
project-machine · Oct 31, 2024 · 075ad2b · 075ad2b
1 parent a256377
commit 075ad2b
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Showing 4 changed files with 21 additions and 19 deletions.
diff --git a/cmd/atomfs/mount.go b/cmd/atomfs/mount.go
@@ -21,8 +21,8 @@ var mountCmd = cli.Command{
 	Action:    doMount,
 	Flags: []cli.Flag{
 		cli.StringFlag{
-			Name:  "persist, upper, upperdir",
-			Usage: "Specify a directory to use as writeable overlay (implies --writeable)",
+			Name:  "persist",
+			Usage: "Specify a directory to use for the workdir and upperdir of a writeable overlay (implies --writeable)",
 		},
 		cli.BoolFlag{
 			Name:  "writeable, writable",

diff --git a/molecule.go b/molecule.go
@@ -242,18 +242,20 @@ func (m Molecule) Mount(dest string) error {
 			return err
 		}
 
-		workdir := filepath.Join(metadir, "work")
-		if err := EnsureDir(workdir); err != nil {
-			return errors.Wrapf(err, "failed to ensure workdir")
+		persistMetaPath := m.config.WriteableOverlayPath
+		if persistMetaPath == "" {
+			// no configured path, use metadir
+			persistMetaPath = metadir
 		}
 
-		upperdir := m.config.WriteableOverlayPath
-		if upperdir == "" {
-			upperdir = filepath.Join(metadir, "persist")
+		workdir := filepath.Join(persistMetaPath, "work")
+		if err := EnsureDir(workdir); err != nil {
+			return errors.Wrapf(err, "failed to ensure workdir %q", workdir)
 		}
 
+		upperdir := filepath.Join(persistMetaPath, "persist")
 		if err := EnsureDir(upperdir); err != nil {
-			return errors.Wrapf(err, "failed to ensure upperdir")
+			return errors.Wrapf(err, "failed to ensure upperdir %q", upperdir)
 		}
 
 		defer func() {

diff --git a/test/priv-mount.bats b/test/priv-mount.bats
@@ -92,7 +92,7 @@ function setup() {
 }
 
 @test "mount with writeable overlay in separate dir" {
-    export PERSIST_DIR=${BATS_TEST_TMPDIR}/upperdir
+    export PERSIST_DIR=${BATS_TEST_TMPDIR}/persist-dir
     mkdir -p $PERSIST_DIR
     run atomfs --debug mount --persist=${PERSIST_DIR} ${BATS_SUITE_TMPDIR}/oci:test-squashfs $MP
     assert_success
@@ -104,9 +104,9 @@ function setup() {
     run cp $MP/1.README.md $MP/3.README.md
     assert_success
 
-    assert_file_exists $PERSIST_DIR/this-time-let-me
-    assert_file_exists $PERSIST_DIR/3.README.md
-    assert_file_not_exists $PERSIST_DIR/1.README.md
+    assert_file_exists $PERSIST_DIR/persist/this-time-let-me
+    assert_file_exists $PERSIST_DIR/persist/3.README.md
+    assert_file_not_exists $PERSIST_DIR/persist/1.README.md
 
     run atomfs --debug umount $MP
     assert_success
@@ -117,6 +117,6 @@ function setup() {
     assert [ -z $( ls -A $ATOMFS_TEST_RUN_DIR/meta/$MY_MNTNSNAME/) ]
 
     # but persist dir should still be there:
-    assert_file_exists $PERSIST_DIR/this-time-let-me
-    assert_file_exists $PERSIST_DIR/3.README.md
+    assert_file_exists $PERSIST_DIR/persist/this-time-let-me
+    assert_file_exists $PERSIST_DIR/persist/3.README.md
 }
diff --git a/test/unpriv-guestmount.bats b/test/unpriv-guestmount.bats
@@ -20,7 +20,7 @@ function setup() {
     lxc-usernsexec -s <<EOF
     set -x
     export ATOMFS_TEST_RUN_DIR=$ATOMFS_TEST_RUN_DIR
-    export PERSIST_DIR=${BATS_TEST_TMPDIR}/upperdir
+    export PERSIST_DIR=${BATS_TEST_TMPDIR}/persist-dir
     mkdir -p \$PERSIST_DIR
 
     export INNER_MNTNSNAME=\$(readlink /proc/self/ns/mnt | cut -c 6-15)
@@ -50,7 +50,7 @@ function setup() {
     find $ATOMFS_TEST_RUN_DIR/meta/\$INNER_MNTNSNAME/
 
     atomfs --debug umount $MP
-    [ -f \$PERSIST_DIR/let-me-write ]
+    [ -f \$PERSIST_DIR/persist/let-me-write ]
 
     # mount point and meta dir should be empty
     [ -d $MP ]
@@ -69,7 +69,7 @@ EOF
     lxc-usernsexec -s <<EOF
     set -x
     export ATOMFS_TEST_RUN_DIR=$ATOMFS_TEST_RUN_DIR
-    export PERSIST_DIR=${BATS_TEST_TMPDIR}/upperdir
+    export PERSIST_DIR=${BATS_TEST_TMPDIR}/persist-dir
     mkdir -p \$PERSIST_DIR
 
     export INNER_MNTNSNAME=\$(readlink /proc/self/ns/mnt | cut -c 6-15)
@@ -88,7 +88,7 @@ EOF
     set -e
 
     atomfs --debug umount $MP
-    [ -f \$PERSIST_DIR/let-me-write ]
+    [ -f \$PERSIST_DIR/persist/let-me-write ]
 
     [ -d $MP ]
     [ -z \$( ls -A $MP) ]