tests/acceptance: Add virtiofs_submounts.py

This test invokes several shell scripts to create a random directory
tree full of submounts, and then check in the VM whether every submount
has its own ID and the structure looks as expected.

(Note that the test scripts must be non-executable, so Avocado will not
try to execute them as if they were tests on their own, too.)

Because at this commit's date it is unlikely that the Linux kernel on
the image provided by boot_linux.py supports submounts in virtio-fs, the
test will be cancelled if no custom Linux binary is provided through the
vmlinuz parameter.  (The on-image kernel can be used by providing an
empty string via vmlinuz=.)

So, invoking the test can be done as follows:
$ avocado run \
    tests/acceptance/virtiofs_submounts.py \
    -p vmlinuz=/path/to/linux/build/arch/x86/boot/bzImage

This test requires root privileges (through passwordless sudo -n),
because at this point, virtiofsd requires them.  (If you have a
timestamp_timeout period for sudoers (e.g. the default of 5 min), you
can provide this by executing something like "sudo true" before invoking
Avocado.)

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20201102161859.156603-8-mreitz@redhat.com>
Tested-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

4 files changed, 341 insertions, 0 deletions

diff --git a/tests/acceptance/virtiofs_submounts.py.data/cleanup.sh b/tests/acceptance/virtiofs_submounts.py.data/cleanup.sh
new file mode 100644
index 0000000000..2a6579a0fe
--- /dev/null
+++ b/tests/acceptance/virtiofs_submounts.py.data/cleanup.sh
@@ -0,0 +1,46 @@
+#!/bin/bash
+
+function print_usage()
+{
+    if [ -n "$2" ]; then
+        echo "Error: $2"
+        echo
+    fi
+    echo "Usage: $1 <scratch dir>"
+}
+
+scratch_dir=$1
+if [ -z "$scratch_dir" ]; then
+    print_usage "$0" 'Scratch dir not given' >&2
+    exit 1
+fi
+
+cd "$scratch_dir/share" || exit 1
+mps=(mnt*)
+mp_i=0
+for mp in "${mps[@]}"; do
+    mp_i=$((mp_i + 1))
+    printf "Unmounting %i/%i...\r" "$mp_i" "${#mps[@]}"
+
+    sudo umount -R "$mp"
+    rm -rf "$mp"
+done
+echo
+
+rm some-file
+cd ..
+rmdir share
+
+imgs=(fs*.img)
+img_i=0
+for img in "${imgs[@]}"; do
+    img_i=$((img_i + 1))
+    printf "Detaching and deleting %i/%i...\r" "$img_i" "${#imgs[@]}"
+
+    dev=$(losetup -j "$img" | sed -e 's/:.*//')
+    sudo losetup -d "$dev"
+    rm -f "$img"
+done
+echo
+
+echo 'Done.'
diff --git a/tests/acceptance/virtiofs_submounts.py.data/guest-cleanup.sh b/tests/acceptance/virtiofs_submounts.py.data/guest-cleanup.sh
new file mode 100644
index 0000000000..729cb2d1a5
--- /dev/null
+++ b/tests/acceptance/virtiofs_submounts.py.data/guest-cleanup.sh
@@ -0,0 +1,30 @@
+#!/bin/bash
+
+function print_usage()
+{
+    if [ -n "$2" ]; then
+        echo "Error: $2"
+        echo
+    fi
+    echo "Usage: $1 <scratch dir>"
+}
+
+scratch_dir=$1
+if [ -z "$scratch_dir" ]; then
+    print_usage "$0" 'Scratch dir not given' >&2
+    exit 1
+fi
+
+cd "$scratch_dir/share" || exit 1
+
+mps=(mnt*)
+mp_i=0
+for mp in "${mps[@]}"; do
+    mp_i=$((mp_i + 1))
+    printf "Unmounting %i/%i...\r" "$mp_i" "${#mps[@]}"
+
+    sudo umount -R "$mp"
+done
+echo
+
+echo 'Done.'
diff --git a/tests/acceptance/virtiofs_submounts.py.data/guest.sh b/tests/acceptance/virtiofs_submounts.py.data/guest.sh
new file mode 100644
index 0000000000..59ba40fde1
--- /dev/null
+++ b/tests/acceptance/virtiofs_submounts.py.data/guest.sh
@@ -0,0 +1,138 @@
+#!/bin/bash
+
+function print_usage()
+{
+    if [ -n "$2" ]; then
+        echo "Error: $2"
+        echo
+    fi
+    echo "Usage: $1 <shared dir>"
+    echo '(The shared directory is the "share" directory in the scratch' \
+         'directory)'
+}
+
+shared_dir=$1
+if [ -z "$shared_dir" ]; then
+    print_usage "$0" 'Shared dir not given' >&2
+    exit 1
+fi
+
+cd "$shared_dir"
+
+# FIXME: This should not be necessary, but it is.  In order for all
+# submounts to be proper mount points, we need to visit them.
+# (Before we visit them, they will not be auto-mounted, and so just
+# appear as normal directories, with the catch that their st_ino will
+# be the st_ino of the filesystem they host, while the st_dev will
+# still be the st_dev of the parent.)
+# `find` does not work, because it will refuse to touch the mount
+# points as long as they are not mounted; their st_dev being shared
+# with the parent and st_ino just being the root node's inode ID
+# will practically ensure that this node exists elsewhere on the
+# filesystem, and `find` is required to recognize loops and not to
+# follow them.
+# Thus, we have to manually visit all nodes first.
+
+mnt_i=0
+
+function recursively_visit()
+{
+    pushd "$1" >/dev/null
+    for entry in *; do
+        if [[ "$entry" == mnt* ]]; then
+            mnt_i=$((mnt_i + 1))
+            printf "Triggering auto-mount $mnt_i...\r"
+        fi
+
+        if [ -d "$entry" ]; then
+            recursively_visit "$entry"
+        fi
+    done
+    popd >/dev/null
+}
+
+recursively_visit .
+echo
+
+
+if [ -n "$(find -name not-mounted)" ]; then
+    echo "Error: not-mounted files visible on mount points:" >&2
+    find -name not-mounted >&2
+    exit 1
+fi
+
+if [ ! -f some-file -o "$(cat some-file)" != 'root' ]; then
+    echo "Error: Bad file in the share root" >&2
+    exit 1
+fi
+
+shopt -s nullglob
+
+function check_submounts()
+{
+    local base_path=$1
+
+    for mp in mnt*; do
+        printf "Checking submount %i...\r" "$((${#devs[@]} + 1))"
+
+        mp_i=$(echo "$mp" | sed -e 's/mnt//')
+        dev=$(stat -c '%D' "$mp")
+
+        if [ -n "${devs[mp_i]}" ]; then
+            echo "Error: $mp encountered twice" >&2
+            exit 1
+        fi
+        devs[mp_i]=$dev
+
+        pushd "$mp" >/dev/null
+        path="$base_path$mp"
+        while true; do
+            expected_content="$(printf '%s\n%s\n' "$mp_i" "$path")"
+            if [ ! -f some-file ]; then
+                echo "Error: $PWD/some-file does not exist" >&2
+                exit 1
+            fi
+
+            if [ "$(cat some-file)" != "$expected_content" ]; then
+                echo "Error: Bad content in $PWD/some-file:" >&2
+                echo '--- found ---'
+                cat some-file
+                echo '--- expected ---'
+                echo "$expected_content"
+                exit 1
+            fi
+            if [ "$(stat -c '%D' some-file)" != "$dev" ]; then
+                echo "Error: $PWD/some-file has the wrong device ID" >&2
+                exit 1
+            fi
+
+            if [ -d sub ]; then
+                if [ "$(stat -c '%D' sub)" != "$dev" ]; then
+                    echo "Error: $PWD/some-file has the wrong device ID" >&2
+                    exit 1
+                fi
+                cd sub
+                path="$path/sub"
+            else
+                if [ -n "$(echo mnt*)" ]; then
+                    check_submounts "$path/"
+                fi
+                break
+            fi
+        done
+        popd >/dev/null
+    done
+}
+
+root_dev=$(stat -c '%D' some-file)
+devs=()
+check_submounts ''
+echo
+
+reused_devs=$(echo "$root_dev ${devs[@]}" | tr ' ' '\n' | sort | uniq -d)
+if [ -n "$reused_devs" ]; then
+    echo "Error: Reused device IDs: $reused_devs" >&2
+    exit 1
+fi
+
+echo "Test passed for ${#devs[@]} submounts."
diff --git a/tests/acceptance/virtiofs_submounts.py.data/host.sh b/tests/acceptance/virtiofs_submounts.py.data/host.sh
new file mode 100644
index 0000000000..d8a9afebdb
--- /dev/null
+++ b/tests/acceptance/virtiofs_submounts.py.data/host.sh
@@ -0,0 +1,127 @@
+#!/bin/bash
+
+mount_count=128
+
+function print_usage()
+{
+    if [ -n "$2" ]; then
+        echo "Error: $2"
+        echo
+    fi
+    echo "Usage: $1 <scratch dir> [seed]"
+    echo "(If no seed is given, it will be randomly generated.)"
+}
+
+scratch_dir=$1
+if [ -z "$scratch_dir" ]; then
+    print_usage "$0" 'No scratch dir given' >&2
+    exit 1
+fi
+
+if [ ! -d "$scratch_dir" ]; then
+    print_usage "$0" "$scratch_dir is not a directory" >&2
+    exit 1
+fi
+
+seed=$2
+if [ -z "$seed" ]; then
+    seed=$RANDOM
+fi
+RANDOM=$seed
+
+echo "Seed: $seed"
+
+set -e
+shopt -s nullglob
+
+cd "$scratch_dir"
+if [ -d share ]; then
+    echo 'Error: This directory seems to be in use already' >&2
+    exit 1
+fi
+
+for ((i = 0; i < $mount_count; i++)); do
+    printf "Setting up fs %i/%i...\r" "$((i + 1))" "$mount_count"
+
+    rm -f fs$i.img
+    truncate -s 512M fs$i.img
+    mkfs.xfs -q fs$i.img
+    devs[i]=$(sudo losetup -f --show fs$i.img)
+done
+echo
+
+top_level_mounts=$((RANDOM % mount_count + 1))
+
+mkdir -p share
+echo 'root' > share/some-file
+
+for ((i = 0; i < $top_level_mounts; i++)); do
+    printf "Mounting fs %i/%i...\r" "$((i + 1))" "$mount_count"
+
+    mkdir -p share/mnt$i
+    touch share/mnt$i/not-mounted
+    sudo mount "${devs[i]}" share/mnt$i
+    sudo chown "$(id -u):$(id -g)" share/mnt$i
+
+    pushd share/mnt$i >/dev/null
+    path=mnt$i
+    nesting=$((RANDOM % 4))
+    for ((j = 0; j < $nesting; j++)); do
+        cat > some-file <<EOF
+$i
+$path
+EOF
+        mkdir sub
+        cd sub
+        path="$path/sub"
+    done
+cat > some-file <<EOF
+$i
+$path
+EOF
+    popd >/dev/null
+done
+
+for ((; i < $mount_count; i++)); do
+    printf "Mounting fs %i/%i...\r" "$((i + 1))" "$mount_count"
+
+    mp_i=$((i % top_level_mounts))
+
+    pushd share/mnt$mp_i >/dev/null
+    path=mnt$mp_i
+    while true; do
+        sub_mp="$(echo mnt*)"
+        if cd sub 2>/dev/null; then
+            path="$path/sub"
+        elif [ -n "$sub_mp" ] && cd "$sub_mp" 2>/dev/null; then
+            path="$path/$sub_mp"
+        else
+            break
+        fi
+    done
+    mkdir mnt$i
+    touch mnt$i/not-mounted
+    sudo mount "${devs[i]}" mnt$i
+    sudo chown "$(id -u):$(id -g)" mnt$i
+
+    cd mnt$i
+    path="$path/mnt$i"
+    nesting=$((RANDOM % 4))
+    for ((j = 0; j < $nesting; j++)); do
+        cat > some-file <<EOF
+$i
+$path
+EOF
+        mkdir sub
+        cd sub
+        path="$path/sub"
+    done
+    cat > some-file <<EOF
+$i
+$path
+EOF
+    popd >/dev/null
+done
+echo
+
+echo 'Done.'