Re: [PATCH v3 4/9] fstests: verify fanotify isolation on cloned filesystems

On Mon, Apr 27, 2026 at 12:20 PM Anand Jain <[email protected]> wrote:
>
> Verify that fanotify events are correctly routed to the appropriate
> watcher when cloned filesystems are mounted.
> Helps verify kernel's event notification distinguishes between devices
> sharing the same FSID/UUID.
>
> Signed-off-by: Anand Jain <[email protected]>
> ---
>  common/config         |   1 +
>  tests/generic/801     | 115 ++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/801.out |   7 +++
>  3 files changed, 123 insertions(+)
>  create mode 100644 tests/generic/801
>  create mode 100644 tests/generic/801.out
>
> diff --git a/common/config b/common/config
> index 605a57947a40..1588bdcb1aa1 100644
> --- a/common/config
> +++ b/common/config
> @@ -243,6 +243,7 @@ export PARTED_PROG="$(type -P parted)"
>  export XFS_PROPERTY_PROG="$(type -P xfs_property)"
>  export FSCRYPTCTL_PROG="$(type -P fscryptctl)"
>  export INOTIFYWAIT_PROG="$(type -P inotifywait)"
> +export FSNOTIFYWAIT_PROG="$(type -P fsnotifywait)"
>
>  # udev wait functions.
>  #
> diff --git a/tests/generic/801 b/tests/generic/801
> new file mode 100644
> index 000000000000..3f64e4de2206
> --- /dev/null
> +++ b/tests/generic/801
> @@ -0,0 +1,115 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2026 Anand Jain <[email protected]>.  All Rights Reserved.
> +#
> +# FS QA Test 801
> +# Verify fanotify FID functionality on cloned filesystems by setting up
> +# watchers and making sure notifications are in the correct logs files.
> +
> +. ./common/preamble
> +
> +_begin_fstest auto quick mount clone
> +
> +_require_test
> +_require_loop

insufficient check for mounting a blockdev fs

> +_require_command "$FSNOTIFYWAIT_PROG" fsnotifywait
> +
> +[ "$FSTYP" = "ext4" ] && _fixed_by_kernel_commit xxxxxxxxxxxx \

Fix before merging

Other than that it looks ok.

Thanks,
Amir.

> +       "ext4: derive f_fsid from block device to avoid collisions"
> +
> +_cleanup()
> +{
> +       cd /
> +       [[ -n $pid1 ]] && { kill -TERM "$pid1" 2> /dev/null; wait $pid1; }
> +       [[ -n $pid2 ]] && { kill -TERM "$pid2" 2> /dev/null; wait $pid2; }
> +       umount $mnt1 $mnt2 2>/dev/null
> +       _loop_image_destroy "${devs[@]}" 2> /dev/null
> +       rm -r -f $tmp.*
> +}
> +
> +monitor_fanotify()
> +{
> +       local mmnt=$1
> +       exec stdbuf -oL $FSNOTIFYWAIT_PROG -m -F -S -e create "$mmnt" 2>&1
> +}
> +
> +fsid_to_fid_parts()
> +{
> +       local fsid=$1
> +       # Pad to 16 hex chars (64-bit), then split into two 32-bit halves
> +       local padded=$(printf '%016x' "0x${fsid}")
> +       local hi=$(printf '%x' "0x${padded:0:8}")   # strips leading zeros
> +       local lo=$(printf '%x' "0x${padded:8:8}")   # strips leading zeros
> +       echo "${hi}.${lo}"
> +}
> +
> +devs=()
> +_loop_image_create_clone devs
> +mkdir -p $TEST_DIR/$seq
> +mnt1=$TEST_DIR/$seq/mnt1
> +mnt2=$TEST_DIR/$seq/mnt2
> +mkdir -p $mnt1
> +mkdir -p $mnt2
> +
> +_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[0]} $mnt1 || \
> +                                               _fail "Failed to mount dev1"
> +_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[1]} $mnt2 || \
> +                                               _fail "Failed to mount dev2"
> +
> +fsid1=$(stat -f -c "%i" $mnt1)
> +fsid2=$(stat -f -c "%i" $mnt2)
> +
> +[[ "$fsid1" == "$fsid2" ]] && \
> +       _notrun "Require clone filesystem with unique f_fsid"
> +
> +log1=$tmp.fanotify1
> +log2=$tmp.fanotify2
> +
> +pid1=""
> +pid2=""
> +echo "Setup FID fanotify watchers on both mnt1 and mnt2"
> +( monitor_fanotify "$mnt1" > "$log1" ) &
> +pid1=$!
> +( monitor_fanotify "$mnt2" > "$log2" ) &
> +pid2=$!
> +sleep 2
> +
> +echo "Trigger file creation on mnt1"
> +touch $mnt1/file_on_mnt1
> +sync
> +sleep 1
> +
> +echo "Trigger file creation on mnt2"
> +touch $mnt2/file_on_mnt2
> +sync
> +sleep 1
> +
> +echo "Verify fsid in the fanotify"
> +kill $pid1 $pid2
> +wait $pid1 $pid2 2>/dev/null
> +pid1=""
> +pid2=""
> +
> +e_fsid1=$(fsid_to_fid_parts "$fsid1")
> +e_fsid2=$(fsid_to_fid_parts "$fsid2")
> +
> +echo $fsid1 $e_fsid1 $fsid2 $e_fsid2 >> $seqres.full
> +cat $log1 >> $seqres.full
> +cat $log2 >> $seqres.full
> +
> +if grep -qF "$e_fsid1" "$log1" && ! grep -qF "$e_fsid2" "$log1"; then
> +       echo "SUCCESS: mnt1 events found"
> +else
> +       [ ! -s "$log1" ] && echo "  - mnt1 received no events."
> +       grep -qF "$e_fsid2" "$log1" && echo "  - mnt1 received event from mnt2."
> +fi
> +
> +if grep -qF "$e_fsid2" "$log2" && ! grep -qF "$e_fsid1" "$log2"; then
> +       echo "SUCCESS: mnt2 events found"
> +else
> +       [ ! -s "$log2" ] && echo "  - mnt2 received no events."
> +       grep -qF "$e_fsid1" "$log2" && echo "  - mnt2 received event from mnt1."
> +fi
> +
> +status=0
> +exit
> diff --git a/tests/generic/801.out b/tests/generic/801.out
> new file mode 100644
> index 000000000000..d7b318d9f27c
> --- /dev/null
> +++ b/tests/generic/801.out
> @@ -0,0 +1,7 @@
> +QA output created by 801
> +Setup FID fanotify watchers on both mnt1 and mnt2
> +Trigger file creation on mnt1
> +Trigger file creation on mnt2
> +Verify fsid in the fanotify
> +SUCCESS: mnt1 events found
> +SUCCESS: mnt2 events found
> --
> 2.43.0
>