* [PATCH v8 01/13] fstests: add _loop_image_create_clone() helper
2026-07-25 7:38 [PATCH v8 0/13] fstests: add test coverage for cloned filesystem ids Anand Jain
@ 2026-07-25 7:38 ` Anand Jain
2026-07-25 7:38 ` [PATCH v8 02/13] fstests: add _clone_mount_option() helper Anand Jain
` (11 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: Anand Jain @ 2026-07-25 7:38 UTC (permalink / raw)
To: fstests; +Cc: linux-btrfs, linux-ext4, linux-xfs, linux-f2fs-devel, zlang,
djwong
Introduce _loop_image_create_clone() and _loop_image_destroy() to mkfs an
image file and clone it to another image file, and attach a loop device to
them. And its destroy part.
Signed-off-by: Anand Jain <asj@kernel.org>
---
common/rc | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
diff --git a/common/rc b/common/rc
index 106f044adc2d..e8ff5be0c547 100644
--- a/common/rc
+++ b/common/rc
@@ -1520,6 +1520,71 @@ _scratch_resvblks()
esac
}
+# Create a small loop image, run an optional tuning function ($2) on it,
+# clone it, and attach both to loop devices, returned in ($1).
+# Args:
+# $1: Nameref to return the array of allocated loop devices [base, clone].
+# $2: Optional callback function to tune the base filesystem before cloning.
+_loop_image_create_clone()
+{
+ local -n _ret=$1
+ local pre_clone_tune_func="$2"
+ local img_file=$TEST_DIR/${seq}.img
+ local img_file_clone=$TEST_DIR/${seq}_clone.img
+ local size=$(_small_fs_size_mb 128) # Smallest possible
+ local loop_devs=()
+
+ # Since we copy the block device image, we keep its size small.
+ _require_fs_space $TEST_DIR $((size * 1024 * 2))
+
+ _create_file_sized $((size * 1024 * 1024)) $img_file ||
+ _fail "Failed: Create $img_file $size"
+
+ loop_devs=("$(_create_loop_device $img_file)")
+
+ case $FSTYP in
+ xfs)
+ _mkfs_dev -s size=4096 "${loop_devs[0]}"
+ ;;
+ btrfs)
+ _mkfs_dev "${loop_devs[0]}"
+ ;;
+ *)
+ _mkfs_dev "${loop_devs[0]}"
+ ;;
+ esac
+
+ # Only execute if the function argument is not empty
+ if [ -n "$pre_clone_tune_func" ]; then
+ $pre_clone_tune_func "${loop_devs[0]}"
+ fi
+
+ sync "${loop_devs[0]}"
+ cp $img_file $img_file_clone || _fail "Failed to copy cloned image"
+
+ loop_devs+=("$(_create_loop_device $img_file_clone)")
+
+ _ret=()
+ for i in "${loop_devs[@]}"; do
+ _ret+=("$i")
+ done
+}
+
+# Teardown loop devices and delete their underlying backing image files.
+# Accepts a list of loop device paths (e.g., /dev/loop0 /dev/loop1).
+_loop_image_destroy()
+{
+ for d in "$@"; do
+ # Retrieve the path of the backing file
+ local f=$(losetup --noheadings --output BACK-FILE $d)
+
+ # Detach the loop device from the backing file
+ _destroy_loop_device "$d"
+
+ # Clean up the backing disk image file
+ [ -n "$f" ] && rm -f "$f"
+ done
+}
# Repair scratch filesystem. Returns 0 if the FS is good to go (either no
# errors found or errors were fixed) and nonzero otherwise; also spits out
--
2.43.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v8 02/13] fstests: add _clone_mount_option() helper
2026-07-25 7:38 [PATCH v8 0/13] fstests: add test coverage for cloned filesystem ids Anand Jain
2026-07-25 7:38 ` [PATCH v8 01/13] fstests: add _loop_image_create_clone() helper Anand Jain
@ 2026-07-25 7:38 ` Anand Jain
2026-07-25 7:39 ` [PATCH v8 03/13] fstests: add FSNOTIFYWAIT_PROG Anand Jain
` (10 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: Anand Jain @ 2026-07-25 7:38 UTC (permalink / raw)
To: fstests; +Cc: linux-btrfs, linux-ext4, linux-xfs, linux-f2fs-devel, zlang,
djwong
Adds _clone_mount_option() helper function to handle filesystem-specific
requirements for mounting cloned devices. Abstract the need for -o nouuid
on XFS.
Signed-off-by: Anand Jain <asj@kernel.org>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
---
common/rc | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/common/rc b/common/rc
index e8ff5be0c547..53e5d9d43af6 100644
--- a/common/rc
+++ b/common/rc
@@ -414,6 +414,19 @@ _scratch_mount_options()
$SCRATCH_DEV $SCRATCH_MNT
}
+# Return filesystem-specific mount options required for mounting clone/snapshot
+# devices.
+_clone_mount_option()
+{
+ case "$FSTYP" in
+ xfs)
+ # Allow mounting a duplicate filesystem on the same host
+ echo "-o nouuid"
+ ;;
+ *)
+ esac
+}
+
_supports_filetype()
{
local dir=$1
--
2.43.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v8 03/13] fstests: add FSNOTIFYWAIT_PROG
2026-07-25 7:38 [PATCH v8 0/13] fstests: add test coverage for cloned filesystem ids Anand Jain
2026-07-25 7:38 ` [PATCH v8 01/13] fstests: add _loop_image_create_clone() helper Anand Jain
2026-07-25 7:38 ` [PATCH v8 02/13] fstests: add _clone_mount_option() helper Anand Jain
@ 2026-07-25 7:39 ` Anand Jain
2026-07-25 7:39 ` [PATCH v8 04/13] fstests: add _require_fanotify_function Anand Jain
` (9 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: Anand Jain @ 2026-07-25 7:39 UTC (permalink / raw)
To: fstests; +Cc: linux-btrfs, linux-ext4, linux-xfs, linux-f2fs-devel, zlang,
djwong
Define `FSNOTIFYWAIT_PROG` for an upcoming test case that uses `fsnotifywait`.
Signed-off-by: Anand Jain <asj@kernel.org>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
---
common/config | 1 +
1 file changed, 1 insertion(+)
diff --git a/common/config b/common/config
index d5299d5b926f..5661fa0ec310 100644
--- a/common/config
+++ b/common/config
@@ -242,6 +242,7 @@ export BTRFS_MAP_LOGICAL_PROG=$(type -P btrfs-map-logical)
export PARTED_PROG="$(type -P parted)"
export XFS_PROPERTY_PROG="$(type -P xfs_property)"
export FSCRYPTCTL_PROG="$(type -P fscryptctl)"
+export FSNOTIFYWAIT_PROG="$(type -P fsnotifywait)"
# udev wait functions.
#
--
2.43.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v8 04/13] fstests: add _require_fanotify_function
2026-07-25 7:38 [PATCH v8 0/13] fstests: add test coverage for cloned filesystem ids Anand Jain
` (2 preceding siblings ...)
2026-07-25 7:39 ` [PATCH v8 03/13] fstests: add FSNOTIFYWAIT_PROG Anand Jain
@ 2026-07-25 7:39 ` Anand Jain
2026-07-25 7:39 ` [PATCH v8 05/13] fstests: add _require_unique_f_fsid() helper Anand Jain
` (8 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: Anand Jain @ 2026-07-25 7:39 UTC (permalink / raw)
To: fstests; +Cc: linux-btrfs, linux-ext4, linux-xfs, linux-f2fs-devel, zlang,
djwong
fanotify support may not be compiled into the kernel. Add
_require_fanotify_function to skip tests when fanotify is disabled.
Signed-off-by: Anand Jain <asj@kernel.org>
---
common/rc | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/common/rc b/common/rc
index 53e5d9d43af6..21b516accdf7 100644
--- a/common/rc
+++ b/common/rc
@@ -6329,6 +6329,13 @@ _require_max_file_range_blocks()
esac
}
+_require_fanotify_function()
+{
+ if $FSNOTIFYWAIT_PROG 2>&1 | grep -q "Function not implemented"; then
+ _notrun "Need CONFIG_FANOTIFY and CONFIG_FANOTIFY_ACCESS_PERMISSIONS to be enabled"
+ fi
+}
+
_require_fanotify_ioerrors()
{
local x
--
2.43.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v8 05/13] fstests: add _require_unique_f_fsid() helper
2026-07-25 7:38 [PATCH v8 0/13] fstests: add test coverage for cloned filesystem ids Anand Jain
` (3 preceding siblings ...)
2026-07-25 7:39 ` [PATCH v8 04/13] fstests: add _require_fanotify_function Anand Jain
@ 2026-07-25 7:39 ` Anand Jain
2026-07-25 7:39 ` [PATCH v8 06/13] fstests: add SEMANAGE_PROG Anand Jain
` (7 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: Anand Jain @ 2026-07-25 7:39 UTC (permalink / raw)
To: fstests; +Cc: linux-btrfs, linux-ext4, linux-xfs, linux-f2fs-devel, zlang,
djwong
Add a helper to check if the target filesystem supports unique f_fsid
tracking across cloned or snapshot instances.
Certain filesystems like XFS, Btrfs, and F2FS ensure unique f_fsid
identifiers per filesystem instance. However, Ext4 derives its f_fsid
directly from its superblock UUID, which leads to identical f_fsid
values on cloned images until the UUID is manually modified by userspace.
Introduce _require_unique_f_fsid() to allow test cases requiring strict
f_fsid uniqueness to skip gracefully on unsupported filesystems.
Signed-off-by: Anand Jain <asj@kernel.org>
---
common/rc | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/common/rc b/common/rc
index 21b516accdf7..f73251365a60 100644
--- a/common/rc
+++ b/common/rc
@@ -6356,6 +6356,33 @@ _require_fanotify_ioerrors()
_notrun "$FSTYP does not support fanotify ioerrors"
}
+# Skip the test if the filesystem does not enforce unique f_fsids
+# natively. Checking this dynamically requires recreating a clone
+# layout, so we use a static lookup based on FSTYP.
+#
+# Across all filesystems, a UUID collision causes libblkid tools to return
+# non-deterministic device mappings. It is ultimately the responsibility
+# of the userspace utility or use-case to enforce uniqueness when a clone
+# diverges. For details, see mailing list thread discussions:
+# Link: https://lore.kernel.org/linux-ext4/20260409131238.GC18443@macsyma-wired.lan/
+_require_unique_f_fsid()
+{
+ case "$FSTYP" in
+ ext*)
+ # Ext4 derives f_fsid from the superblock UUID, meaning
+ # clones share the same f_fsid until their UUIDs
+ # diverge.
+ _notrun "Target filesystem ($FSTYP) does not guarantee unique f_fsid on clones."
+ ;;
+ *)
+ # Conversely, XFS, Btrfs, and F2FS ensure f_fsid remains
+ # unique per filesystem instance (often by deriving it
+ # from the UUID and underlying block device.)
+ ;;
+ esac
+}
+
+
# Computes a percentage of the available space in a filesystem and
# returns that quantity in MB. The percentage must not contain a percent
# sign ("%").
--
2.43.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v8 06/13] fstests: add SEMANAGE_PROG
2026-07-25 7:38 [PATCH v8 0/13] fstests: add test coverage for cloned filesystem ids Anand Jain
` (4 preceding siblings ...)
2026-07-25 7:39 ` [PATCH v8 05/13] fstests: add _require_unique_f_fsid() helper Anand Jain
@ 2026-07-25 7:39 ` Anand Jain
2026-07-25 7:39 ` [PATCH v8 07/13] fstests: verify fanotify isolation on cloned filesystems Anand Jain
` (6 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: Anand Jain @ 2026-07-25 7:39 UTC (permalink / raw)
To: fstests; +Cc: linux-btrfs, linux-ext4, linux-xfs, linux-f2fs-devel, zlang,
djwong
Define `SEMANAGE_PROG` for an upcoming test case that uses `semanage(8)`.
Signed-off-by: Anand Jain <asj@kernel.org>
---
common/config | 1 +
1 file changed, 1 insertion(+)
diff --git a/common/config b/common/config
index 5661fa0ec310..d760b796ce86 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="$(type -P fscryptctl)"
export FSNOTIFYWAIT_PROG="$(type -P fsnotifywait)"
+export SEMANAGE_PROG="$(type -P semanage)"
# udev wait functions.
#
--
2.43.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v8 07/13] fstests: verify fanotify isolation on cloned filesystems
2026-07-25 7:38 [PATCH v8 0/13] fstests: add test coverage for cloned filesystem ids Anand Jain
` (5 preceding siblings ...)
2026-07-25 7:39 ` [PATCH v8 06/13] fstests: add SEMANAGE_PROG Anand Jain
@ 2026-07-25 7:39 ` Anand Jain
2026-07-25 7:39 ` [PATCH v8 08/13] fstests: verify f_fsid for " Anand Jain
` (5 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: Anand Jain @ 2026-07-25 7:39 UTC (permalink / raw)
To: fstests; +Cc: linux-btrfs, linux-ext4, linux-xfs, linux-f2fs-devel, zlang,
djwong
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 <asj@kernel.org>
---
tests/generic/801 | 143 ++++++++++++++++++++++++++++++++++++++++++
tests/generic/801.out | 7 +++
2 files changed, 150 insertions(+)
create mode 100644 tests/generic/801
create mode 100644 tests/generic/801.out
diff --git a/tests/generic/801 b/tests/generic/801
new file mode 100644
index 000000000000..904ba9440b3d
--- /dev/null
+++ b/tests/generic/801
@@ -0,0 +1,143 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 Anand Jain <asj@kernel.org>. 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_block_device $TEST_DEV
+_require_loop
+_require_command "$SEMANAGE_PROG" semanage
+_require_command "$FSNOTIFYWAIT_PROG" fsnotifywait
+_require_fanotify_function
+_require_unique_f_fsid
+
+_cleanup()
+{
+ cd /
+ [[ -n $pid1 ]] && { kill -TERM "$pid1" 2> /dev/null; wait $pid1; }
+ [[ -n $pid2 ]] && { kill -TERM "$pid2" 2> /dev/null; wait $pid2; }
+
+ if [ "$semanage_added" = "yes" ]; then
+ semanage permissive -d unconfined_t >/dev/null 2>&1 || true
+ fi
+
+ umount $mnt1 $mnt2 >/dev/null 2>&1
+ _loop_image_destroy "${devs[@]}" 2> /dev/null
+ rm -r -f $tmp.*
+}
+
+# Run fsnotifywait in unbuffered mode to watch filesystem-wide create events
+monitor_fanotify()
+{
+ local mmnt=$1
+ exec stdbuf -oL $FSNOTIFYWAIT_PROG -m -F -S -e create "$mmnt" 2>&1
+}
+
+# Transform f_fsid into the hi.lo format used in fanotify FID logs
+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}"
+}
+
+# Create base loop device and its clone
+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 both base and clone filesystems using required clone mount options
+_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]} $mnt2 || \
+ _fail "Failed to mount dev2"
+
+# Fetch filesystem IDs to verify the kernel can differentiate between them
+fsid1=$(stat -f -c "%i" $mnt1)
+fsid2=$(stat -f -c "%i" $mnt2)
+
+log1=$tmp.fanotify1
+log2=$tmp.fanotify2
+
+pid1=""
+pid2=""
+echo "Setup FID fanotify watchers on both mnt1 and mnt2"
+
+# Permit unconfined_t domains when SELinux is enforcing to prevent fanotify
+# blockages
+semanage_added="no"
+if [ "$(getenforce 2>/dev/null)" = "Enforcing" ]; then
+ if ! semanage permissive -l | grep -q "unconfined_t"; then
+ semanage permissive -a unconfined_t >/dev/null 2>&1 && semanage_added="yes"
+ fi
+fi
+
+# Start asynchronous fanotify monitors
+( monitor_fanotify "$mnt1" > "$log1" ) &
+pid1=$!
+( monitor_fanotify "$mnt2" > "$log2" ) &
+pid2=$!
+sleep 2
+
+if ! kill -0 "$pid1" 2>/dev/null || ! kill -0 "$pid2" 2>/dev/null; then
+ cat "$log1"
+ cat "$log2"
+ _fail "$FSNOTIFYWAIT_PROG setup failed"
+fi
+
+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")
+
+# Dump debug details to the full log
+echo $fsid1 $e_fsid1 $fsid2 $e_fsid2 >> $seqres.full
+cat $log1 >> $seqres.full
+cat $log2 >> $seqres.full
+
+# Ensure monitor 1 only captured events belonging to mnt 1 and fsid 1
+if grep -qF "$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
+
+# Ensure monitor 2 only captured events belonging to mnt 2 and fsid 2
+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
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v8 08/13] fstests: verify f_fsid for cloned filesystems
2026-07-25 7:38 [PATCH v8 0/13] fstests: add test coverage for cloned filesystem ids Anand Jain
` (6 preceding siblings ...)
2026-07-25 7:39 ` [PATCH v8 07/13] fstests: verify fanotify isolation on cloned filesystems Anand Jain
@ 2026-07-25 7:39 ` Anand Jain
2026-07-25 7:39 ` [PATCH v8 09/13] fstests: verify libblkid resolution of duplicate UUIDs Anand Jain
` (4 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: Anand Jain @ 2026-07-25 7:39 UTC (permalink / raw)
To: fstests; +Cc: linux-btrfs, linux-ext4, linux-xfs, linux-f2fs-devel, zlang,
djwong
Verify that the cloned filesystem provides an f_fsid that is persistent
across mount cycles, yet unique from the original filesystem's f_fsid.
Signed-off-by: Anand Jain <asj@kernel.org>
---
tests/generic/802 | 64 +++++++++++++++++++++++++++++++++++++++++++
tests/generic/802.out | 4 +++
2 files changed, 68 insertions(+)
create mode 100644 tests/generic/802
create mode 100644 tests/generic/802.out
diff --git a/tests/generic/802 b/tests/generic/802
new file mode 100644
index 000000000000..910807c11584
--- /dev/null
+++ b/tests/generic/802
@@ -0,0 +1,64 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 Anand Jain <asj@kernel.org>. All Rights Reserved.
+#
+# FS QA Test 802
+# Check that the cloned filesystem provides an f_fsid that is persistent
+# across mount cycles if the block device maj:min remains unchanged.
+
+. ./common/preamble
+
+_begin_fstest auto quick mount clone
+
+_require_test
+_require_block_device $TEST_DEV
+_require_loop
+
+_fixed_by_fs_commit btrfs xxxxxxxxxxxx \
+ "btrfs: use on-disk uuid for s_uuid in temp_fsid mounts"
+_fixed_by_fs_commit btrfs xxxxxxxxxxxx \
+ "btrfs: derive f_fsid from on-disk fsuuid and dev_t"
+
+_cleanup()
+{
+ cd /
+ rm -r -f $tmp.*
+ umount $mnt1 $mnt2 2>/dev/null
+ _loop_image_destroy "${devs[@]}" 2> /dev/null
+}
+
+# Setup base loop device and its clone
+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 both filesystems simultaneously using mandatory clone mount options
+_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]} $mnt2 || \
+ _fail "Failed to mount dev2"
+
+# Capture baseline filesystem IDs for comparison
+fsid_scratch=$(stat -f -c "%i" $mnt1)
+fsid_clone=$(stat -f -c "%i" $mnt2)
+
+# Verify that the fsids remain stable after a mount cycle, even when the
+# mount order is reversed.
+echo "**** fsid after mount cycle ****"
+_unmount $mnt1
+_unmount $mnt2
+_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[1]} $mnt2 || \
+ _fail "Failed to mount dev2"
+_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[0]} $mnt1 || \
+ _fail "Failed to mount dev1"
+
+# Compare post mount-cycle values against the baseline
+stat -f -c "%i" $mnt1 | sed -e "s/$fsid_scratch/FSID_SCRATCH/g"
+stat -f -c "%i" $mnt2 | sed -e "s/$fsid_clone/FSID_CLONE/g"
+
+status=0
+exit
diff --git a/tests/generic/802.out b/tests/generic/802.out
new file mode 100644
index 000000000000..0202a9a2c108
--- /dev/null
+++ b/tests/generic/802.out
@@ -0,0 +1,4 @@
+QA output created by 802
+**** fsid after mount cycle ****
+FSID_SCRATCH
+FSID_CLONE
--
2.43.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v8 09/13] fstests: verify libblkid resolution of duplicate UUIDs
2026-07-25 7:38 [PATCH v8 0/13] fstests: add test coverage for cloned filesystem ids Anand Jain
` (7 preceding siblings ...)
2026-07-25 7:39 ` [PATCH v8 08/13] fstests: verify f_fsid for " Anand Jain
@ 2026-07-25 7:39 ` Anand Jain
2026-07-25 7:39 ` [PATCH v8 10/13] fstests: verify IMA isolation on cloned filesystems Anand Jain
` (3 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: Anand Jain @ 2026-07-25 7:39 UTC (permalink / raw)
To: fstests; +Cc: linux-btrfs, linux-ext4, linux-xfs, linux-f2fs-devel, zlang,
djwong
Verify how findmnt, df (libblkid) resolve device paths when multiple
block devices share the same FSUUID.
Signed-off-by: Anand Jain <asj@kernel.org>
---
tests/generic/803 | 72 +++++++++++++++++++++++++++++++++++++++++++
tests/generic/803.out | 6 ++++
2 files changed, 78 insertions(+)
create mode 100644 tests/generic/803
create mode 100644 tests/generic/803.out
diff --git a/tests/generic/803 b/tests/generic/803
new file mode 100644
index 000000000000..77901592366c
--- /dev/null
+++ b/tests/generic/803
@@ -0,0 +1,72 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 Anand Jain <asj@kernel.org>. All Rights Reserved.
+#
+# FS QA Test 803
+# Check if the mountinfo based findmnt would resolve to the common uuid
+# as per the blkid (libblkid based).
+
+. ./common/preamble
+. ./common/filter
+
+_begin_fstest auto quick mount clone
+
+_require_test
+_require_block_device $TEST_DEV
+_require_loop
+
+_cleanup()
+{
+ cd /
+ rm -r -f $tmp.*
+ umount $mnt1 $mnt2 2>/dev/null
+ _loop_image_destroy "${devs[@]}" 2> /dev/null
+}
+
+# Normalize pool devices and mount points names
+filter_pool()
+{
+ sed -e "s|${devs[0]}|DEV1|g" -e "s|${mnt1}|MNT1|g" \
+ -e "s|${devs[1]}|DEV2|g" -e "s|${mnt2}|MNT2|g" | _filter_spaces
+}
+
+# Setup base loop device and its clone
+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 $mnt2
+
+# Get the uuid from the source device
+fsuuid=$(blkid -s UUID -o value ${devs[0]})
+
+# Mount both identical UUID filesystems simultaneously
+_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]} $mnt2 || \
+ _fail "Failed to mount dev2"
+
+findmnt -o SOURCE,TARGET,UUID "${devs[0]}" | tail -n +2 | \
+ sed -e "s/${fsuuid}/FSUUID/g" | filter_pool
+findmnt -o SOURCE,TARGET,UUID "${devs[1]}" | tail -n +2 | \
+ sed -e "s/${fsuuid}/FSUUID/g" | filter_pool
+
+# Btrfs assigned a random uuid for the clone fs before the fix.
+# Cycle mounts and reverse the initialization (source and clone fs) order.
+echo "**** mount cycle ****"
+_unmount $mnt1
+_unmount $mnt2
+_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[1]} $mnt2 || \
+ _fail "Failed to mount dev2"
+_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[0]} $mnt1 || \
+ _fail "Failed to mount dev1"
+
+findmnt -o SOURCE,TARGET,UUID "${devs[0]}" | tail -n +2 | \
+ sed -e "s/${fsuuid}/FSUUID/g" | filter_pool
+findmnt -o SOURCE,TARGET,UUID "${devs[1]}" | tail -n +2 | \
+ sed -e "s/${fsuuid}/FSUUID/g" | filter_pool
+
+status=0
+exit
diff --git a/tests/generic/803.out b/tests/generic/803.out
new file mode 100644
index 000000000000..3a130c662430
--- /dev/null
+++ b/tests/generic/803.out
@@ -0,0 +1,6 @@
+QA output created by 803
+DEV1 MNT1 FSUUID
+DEV2 MNT2 FSUUID
+**** mount cycle ****
+DEV1 MNT1 FSUUID
+DEV2 MNT2 FSUUID
--
2.43.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v8 10/13] fstests: verify IMA isolation on cloned filesystems
2026-07-25 7:38 [PATCH v8 0/13] fstests: add test coverage for cloned filesystem ids Anand Jain
` (8 preceding siblings ...)
2026-07-25 7:39 ` [PATCH v8 09/13] fstests: verify libblkid resolution of duplicate UUIDs Anand Jain
@ 2026-07-25 7:39 ` Anand Jain
2026-07-25 7:39 ` [PATCH v8 11/13] fstests: verify exportfs file handles " Anand Jain
` (2 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: Anand Jain @ 2026-07-25 7:39 UTC (permalink / raw)
To: fstests; +Cc: linux-btrfs, linux-ext4, linux-xfs, linux-f2fs-devel, zlang,
djwong
Add testcase to verify IMA measurement isolation when multiple devices
share the same FSUUID.
Signed-off-by: Anand Jain <asj@kernel.org>
---
tests/generic/804 | 108 ++++++++++++++++++++++++++++++++++++++++++
tests/generic/804.out | 10 ++++
2 files changed, 118 insertions(+)
create mode 100644 tests/generic/804
create mode 100644 tests/generic/804.out
diff --git a/tests/generic/804 b/tests/generic/804
new file mode 100644
index 000000000000..ced32e6d79dd
--- /dev/null
+++ b/tests/generic/804
@@ -0,0 +1,108 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 Anand Jain <asj@kernel.org>. All Rights Reserved.
+#
+# FS QA Test 804
+# Verify IMA isolation on cloned filesystems:
+# . Mount two devices sharing the same FSUUID (cloned).
+# . Apply an IMA policy to measure files based on that FSUUID.
+# . Create unique files on each mount point to trigger measurements.
+# . Confirm the IMA log correctly attributes events to the respective mounts.
+
+. ./common/preamble
+. ./common/filter
+
+_begin_fstest auto quick clone
+
+_require_test
+_require_block_device $TEST_DEV
+_require_loop
+
+_fixed_by_fs_commit btrfs xxxxxxxxxxxx \
+ "btrfs: use on-disk uuid for s_uuid in temp_fsid mounts"
+_fixed_by_fs_commit btrfs xxxxxxxxxxxx \
+ "btrfs: derive f_fsid from on-disk fsuuid and dev_t"
+
+_cleanup()
+{
+ cd /
+ rm -r -f $tmp.*
+ _unmount $mnt1 2>/dev/null
+ _unmount $mnt2 2>/dev/null
+ _loop_image_destroy "${devs[@]}" 2> /dev/null
+}
+
+# Normalize device names and mount points
+filter_pool()
+{
+ sed -e "s|${devs[0]}|DEV1|g" -e "s|$mnt1|MNT1|g" \
+ -e "s|${devs[1]}|DEV2|g" -e "s|$mnt2|MNT2|g" | _filter_spaces
+}
+
+# Core helper to set IMA policy and check measurement logs
+do_ima()
+{
+ local ima_policy="/sys/kernel/security/ima/policy"
+ local ima_log="/sys/kernel/security/ima/ascii_runtime_measurements"
+ local fsuuid
+ local mnt=$1
+ local enable=$2
+
+ # Since the in-memory IMA audit log is only cleared upon reboot,
+ # use unique random filenames to avoid log collisions.
+ local foofile=$(mktemp --dry-run foobar_XXXXX)
+
+ echo $mnt $enable | filter_pool
+
+ [ -w "$ima_policy" ] || _notrun "IMA policy not writable"
+
+ fsuuid=$(blkid -s UUID -o value ${devs[0]})
+
+ # Load IMA policy to measure file access specifically for this
+ # filesystem UUID.
+ if [[ $enable -eq 1 ]]; then
+ echo "measure func=FILE_CHECK fsuuid=$fsuuid" > "$ima_policy" || \
+ _notrun "Policy rejected"
+ fi
+
+ # Create a file to trigger measurement and verify its entry in
+ # the IMA log.
+ echo "test_data" > $mnt/$foofile
+
+ # IMA log extract
+ grep $foofile "$ima_log" | awk '{ print $5 }' | filter_pool | \
+ sed "s/$foofile/FOOBAR_FILE/"
+
+ echo "dbg: $mnt $fsuuid $foofile" >> $seqres.full
+ cat $ima_log | tail -1 >> $seqres.full
+ echo >> $seqres.full
+}
+
+# Initialize loop base and cloned instances
+devs=()
+_loop_image_create_clone devs
+mnt1=$TEST_DIR/$seq/mnt1
+mnt2=$TEST_DIR/$seq/mnt2
+mkdir -p $mnt1
+mkdir -p $mnt2
+
+# Concurrently mount both clones
+_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"
+
+# IMA response on baseline and clone configuration
+do_ima $mnt1 1
+do_ima $mnt2 0
+
+# Cycle mount on the second device.
+echo mount cycle
+_unmount $mnt2
+_mount $mount_opts ${devs[1]} $mnt2 || _fail "Failed to mount dev2"
+
+do_ima $mnt1 0
+do_ima $mnt2 0
+
+status=0
+exit
diff --git a/tests/generic/804.out b/tests/generic/804.out
new file mode 100644
index 000000000000..9804181d6c17
--- /dev/null
+++ b/tests/generic/804.out
@@ -0,0 +1,10 @@
+QA output created by 804
+MNT1 1
+MNT1/FOOBAR_FILE
+MNT2 0
+MNT2/FOOBAR_FILE
+mount cycle
+MNT1 0
+MNT1/FOOBAR_FILE
+MNT2 0
+MNT2/FOOBAR_FILE
--
2.43.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v8 11/13] fstests: verify exportfs file handles on cloned filesystems
2026-07-25 7:38 [PATCH v8 0/13] fstests: add test coverage for cloned filesystem ids Anand Jain
` (9 preceding siblings ...)
2026-07-25 7:39 ` [PATCH v8 10/13] fstests: verify IMA isolation on cloned filesystems Anand Jain
@ 2026-07-25 7:39 ` Anand Jain
2026-07-25 7:39 ` [PATCH v8 12/13] fstests: add _change_metadata_uuid helper Anand Jain
2026-07-25 7:39 ` [PATCH v8 13/13] fstests: test UUID consistency for clones with metadata_uuid Anand Jain
12 siblings, 0 replies; 14+ messages in thread
From: Anand Jain @ 2026-07-25 7:39 UTC (permalink / raw)
To: fstests; +Cc: linux-btrfs, linux-ext4, linux-xfs, linux-f2fs-devel, zlang,
djwong
Ensure that exportfs can correctly decode file handles on a cloned
filesystem across a mount cycle, by file handles generated on a
cloned device remain valid after mount cycle.
Signed-off-by: Anand Jain <asj@kernel.org>
---
tests/generic/805 | 80 +++++++++++++++++++++++++++++++++++++++++++
tests/generic/805.out | 2 ++
2 files changed, 82 insertions(+)
create mode 100644 tests/generic/805
create mode 100644 tests/generic/805.out
diff --git a/tests/generic/805 b/tests/generic/805
new file mode 100644
index 000000000000..5827eee039df
--- /dev/null
+++ b/tests/generic/805
@@ -0,0 +1,80 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 Anand Jain <asj@kernel.org>. All Rights Reserved.
+#
+# FS QA Test No. 805
+# Verify that file handles encoded on a cloned filesystem remain valid and
+# resolvable via open_by_handle across a mount cycle and mount order swap.
+
+. ./common/preamble
+
+_begin_fstest auto quick exportfs clone
+
+_require_test
+_require_block_device $TEST_DEV
+_require_exportfs
+_require_loop
+_require_test_program "open_by_handle"
+
+_cleanup()
+{
+ cd /
+ rm -r -f $tmp.*
+ _unmount $mnt1 2>/dev/null
+ _unmount $mnt2 2>/dev/null
+ _loop_image_destroy "${devs[@]}" 2> /dev/null
+}
+
+# Create test dir and test files, encode file handles and store to tmp file
+create_test_files()
+{
+ rm -rf $testdir
+ mkdir -p $testdir
+ $here/src/open_by_handle -cwp -o $tmp.handles_file $testdir $NUMFILES
+}
+
+# Attempt to read and decode the saved file handles on the targeted mount point.
+test_file_handles()
+{
+ local opt=$1
+ local when=$2
+
+ echo test_file_handles after $when
+ $here/src/open_by_handle $opt -i $tmp.handles_file $mnt2 $NUMFILES
+}
+
+# Setup base loop device and its clone
+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 both identical UUID filesystems simultaneously
+_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]} $mnt2 || \
+ _fail "Failed to mount dev2"
+
+NUMFILES=1
+testdir=$mnt2/testdir
+
+# Decode file handles of files/dir after cycle mount
+create_test_files
+
+# Cycle mounts and reverse initialization sequence to check if
+# file handle lookups are okay
+_unmount $mnt1
+_unmount $mnt2
+_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[1]} $mnt2 || \
+ _fail "Failed to mount dev2"
+_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[0]} $mnt1 || \
+ _fail "Failed to mount dev1"
+
+# Verify file handles can still be resolved post-mount-cycle
+test_file_handles -rp "cycle mount"
+
+status=0
+exit
diff --git a/tests/generic/805.out b/tests/generic/805.out
new file mode 100644
index 000000000000..29b11ec77ffb
--- /dev/null
+++ b/tests/generic/805.out
@@ -0,0 +1,2 @@
+QA output created by 805
+test_file_handles after cycle mount
--
2.43.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v8 12/13] fstests: add _change_metadata_uuid helper
2026-07-25 7:38 [PATCH v8 0/13] fstests: add test coverage for cloned filesystem ids Anand Jain
` (10 preceding siblings ...)
2026-07-25 7:39 ` [PATCH v8 11/13] fstests: verify exportfs file handles " Anand Jain
@ 2026-07-25 7:39 ` Anand Jain
2026-07-25 7:39 ` [PATCH v8 13/13] fstests: test UUID consistency for clones with metadata_uuid Anand Jain
12 siblings, 0 replies; 14+ messages in thread
From: Anand Jain @ 2026-07-25 7:39 UTC (permalink / raw)
To: fstests; +Cc: linux-btrfs, linux-ext4, linux-xfs, linux-f2fs-devel, zlang,
djwong
_change_metadata_uuid changes the UUID of the golden filesystem before it
is cloned.
Signed-off-by: Anand Jain <asj@kernel.org>
---
common/rc | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/common/rc b/common/rc
index f73251365a60..45cf9360ba73 100644
--- a/common/rc
+++ b/common/rc
@@ -1533,6 +1533,29 @@ _scratch_resvblks()
esac
}
+# Change the metadata UUID of the given device to a newly generated one.
+# Args:
+# $1: Block device path to modify.
+_change_metadata_uuid()
+{
+ local temp_mnt=$TEST_DIR/${seq}_mnt
+ local dev=$1
+
+ case $FSTYP in
+ xfs)
+ _require_command "$XFS_ADMIN_PROG" "xfs_admin"
+ $XFS_ADMIN_PROG -U generate $dev >> $seqres.full
+ ;;
+ btrfs)
+ _require_command "$BTRFS_TUNE_PROG" "btrfstune"
+ $BTRFS_TUNE_PROG -m $dev
+ ;;
+ *)
+ _notrun "Require filesystem with metadata_uuid feature"
+ ;;
+ esac
+}
+
# Create a small loop image, run an optional tuning function ($2) on it,
# clone it, and attach both to loop devices, returned in ($1).
# Args:
--
2.43.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* [PATCH v8 13/13] fstests: test UUID consistency for clones with metadata_uuid
2026-07-25 7:38 [PATCH v8 0/13] fstests: add test coverage for cloned filesystem ids Anand Jain
` (11 preceding siblings ...)
2026-07-25 7:39 ` [PATCH v8 12/13] fstests: add _change_metadata_uuid helper Anand Jain
@ 2026-07-25 7:39 ` Anand Jain
12 siblings, 0 replies; 14+ messages in thread
From: Anand Jain @ 2026-07-25 7:39 UTC (permalink / raw)
To: fstests; +Cc: linux-btrfs, linux-ext4, linux-xfs, linux-f2fs-devel, zlang,
djwong
Btrfs and xfs uses the metadata_uuid superblock feature to change the
on-disk UUID without rewriting every block header. This patch adds a
sanity check to ensure UUID consistency when a filesystem with
metadata_uuid enabled is cloned.
Signed-off-by: Anand Jain <asj@kernel.org>
---
tests/generic/806 | 74 +++++++++++++++++++++++++++++++++++++++++++
tests/generic/806.out | 6 ++++
2 files changed, 80 insertions(+)
create mode 100644 tests/generic/806
create mode 100644 tests/generic/806.out
diff --git a/tests/generic/806 b/tests/generic/806
new file mode 100644
index 000000000000..6d3166491006
--- /dev/null
+++ b/tests/generic/806
@@ -0,0 +1,74 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2026 Anand Jain <asj@kernel.org>. All Rights Reserved.
+#
+# FS QA Test 806
+#
+# Verify that the cloned filesystem UUID remains consistent, even when the
+# `metadata_uuid` feature is enabled.
+#
+
+. ./common/preamble
+. ./common/filter
+
+_begin_fstest auto quick mount clone
+
+_require_test
+_require_block_device $TEST_DEV
+_require_loop
+
+_cleanup()
+{
+ cd /
+ rm -r -f $tmp.*
+ umount $mnt1 $mnt2 2>/dev/null
+ _loop_image_destroy "${devs[@]}" 2> /dev/null
+}
+
+filter_pool()
+{
+ sed -e "s|${devs[0]}|DEV1|g" -e "s|${mnt1}|MNT1|g" \
+ -e "s|${devs[1]}|DEV2|g" -e "s|${mnt2}|MNT2|g" | _filter_spaces
+}
+
+# Create base loop device and its clone, applying the metadata_uuid tuning
+# callback to the base filesystem before the copy occurs.
+devs=()
+_loop_image_create_clone devs _change_metadata_uuid
+mkdir -p $TEST_DIR/$seq
+mnt1=$TEST_DIR/$seq/mnt1
+mnt2=$TEST_DIR/$seq/mnt2
+mkdir -p $mnt1
+mkdir -p $mnt2
+
+# Get the uuid from the source device
+fsuuid=$(blkid -s UUID -o value ${devs[0]})
+
+# Mount both clone and baseline
+_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]} $mnt2 || \
+ _fail "Failed to mount dev2"
+
+findmnt -o SOURCE,TARGET,UUID "${devs[0]}" | tail -n +2 | \
+ sed -e "s/${fsuuid}/FSUUID/g" | filter_pool
+findmnt -o SOURCE,TARGET,UUID "${devs[1]}" | tail -n +2 | \
+ sed -e "s/${fsuuid}/FSUUID/g" | filter_pool
+
+# Cycle mounts and reverse the initialization order to ensure UUID tracking
+# doesn't mismatch or flip when metadata_uuid optimization is active.
+echo "**** mount cycle ****"
+_unmount $mnt1
+_unmount $mnt2
+_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[1]} $mnt2 || \
+ _fail "Failed to mount dev2"
+_mount $(_common_dev_mount_options) $(_clone_mount_option) ${devs[0]} $mnt1 || \
+ _fail "Failed to mount dev1"
+
+findmnt -o SOURCE,TARGET,UUID "${devs[0]}" | tail -n +2 | \
+ sed -e "s/${fsuuid}/FSUUID/g" | filter_pool
+findmnt -o SOURCE,TARGET,UUID "${devs[1]}" | tail -n +2 | \
+ sed -e "s/${fsuuid}/FSUUID/g" | filter_pool
+
+status=0
+exit
diff --git a/tests/generic/806.out b/tests/generic/806.out
new file mode 100644
index 000000000000..918f422ecddf
--- /dev/null
+++ b/tests/generic/806.out
@@ -0,0 +1,6 @@
+QA output created by 806
+DEV1 MNT1 FSUUID
+DEV2 MNT2 FSUUID
+**** mount cycle ****
+DEV1 MNT1 FSUUID
+DEV2 MNT2 FSUUID
--
2.43.0
^ permalink raw reply related [flat|nested] 14+ messages in thread