fstests: test Btrfs swapfile support

index c74d6c70..04ed3e73 100755
@@ -51,7 +51,7 @@ swapfile_cycle() {
 	$CHATTR_PROG +C $swapfile >> $seqres.full 2>&1
 	"$here/src/mkswap" $swapfile >> $seqres.full
 	"$here/src/swapon" $swapfile 2>&1 | _filter_scratch
-	swapoff $swapfile 2>> $seeqres.full
+	swapoff $swapfile 2>> $seqres.full
 	rm -f $swapfile
 }
 

index 1c9651ad..968b8012 100755
@@ -53,7 +53,7 @@ swapfile_cycle() {
 	$CHATTR_PROG +C $swapfile >> $seqres.full 2>&1
 	"$here/src/mkswap" $swapfile >> $seqres.full
 	"$here/src/swapon" $swapfile 2>&1 | _filter_scratch
-	swapoff $swapfile 2>> $seeqres.full
+	swapoff $swapfile 2>> $seqres.full
 	rm -f $swapfile
 }
 

index 584af58a..3d5502ef 100755
@@ -53,7 +53,7 @@ swapfile_cycle() {
 	$CHATTR_PROG +C $swapfile >> $seqres.full 2>&1
 	"$here/src/mkswap" $swapfile >> $seqres.full
 	"$here/src/swapon" $swapfile 2>&1 | _filter_scratch
-	swapoff $swapfile 2>> $seeqres.full
+	swapoff $swapfile 2>> $seqres.full
 	rm -f $swapfile
 }
 

index 04ed3e73..aba4a007 100755
@@ -42,13 +42,15 @@ _scratch_mount >>$seqres.full 2>&1
 
 swapfile=$SCRATCH_MNT/swap
 len=$((2 * 1048576))
-page_size=$(get_page_size)
 
 swapfile_cycle() {
 	local swapfile="$1"
+	local len="$2"
 
+	touch $swapfile
 	# Swap files must be nocow on Btrfs.
 	$CHATTR_PROG +C $swapfile >> $seqres.full 2>&1
+	_pwrite_byte 0x58 0 $len $swapfile >> $seqres.full
 	"$here/src/mkswap" $swapfile >> $seqres.full
 	"$here/src/swapon" $swapfile 2>&1 | _filter_scratch
 	swapoff $swapfile 2>> $seqres.full

@@ -57,20 +59,16 @@ swapfile_cycle() {
 
 # Create a regular swap file
 echo "regular swap" | tee -a $seqres.full
-_pwrite_byte 0x58 0 $len $swapfile >> $seqres.full
-swapfile_cycle $swapfile
+swapfile_cycle $swapfile $len
 
 # Create a swap file with a little too much junk on the end
 echo "too long swap" | tee -a $seqres.full
-_pwrite_byte 0x58 0 $((len + 3)) $swapfile >> $seqres.full
-swapfile_cycle $swapfile
+swapfile_cycle $swapfile $((len + 3))
 
 # Create a ridiculously small swap file.  Each swap file must have at least
 # two pages after the header page.
 echo "tiny swap" | tee -a $seqres.full
-tiny_len=$((page_size * 3))
-_pwrite_byte 0x58 0 $tiny_len $swapfile >> $seqres.full
-swapfile_cycle $swapfile
+swapfile_cycle $swapfile $(($(get_page_size) * 3))
 
 status=0
 exit

index 968b8012..3083eef0 100755
@@ -49,8 +49,6 @@ page_size=$(get_page_size)
 swapfile_cycle() {
 	local swapfile="$1"
 
-	# Swap files must be nocow on Btrfs.
-	$CHATTR_PROG +C $swapfile >> $seqres.full 2>&1
 	"$here/src/mkswap" $swapfile >> $seqres.full
 	"$here/src/swapon" $swapfile 2>&1 | _filter_scratch
 	swapoff $swapfile 2>> $seqres.full

@@ -59,8 +57,10 @@ swapfile_cycle() {
 
 # Create a fallocated swap file
 echo "fallocate swap" | tee -a $seqres.full
-$XFS_IO_PROG -f -c "falloc 0 $len" $swapfile >> $seqres.full
+touch $swapfile
+# Swap files must be nocow on Btrfs.
 $CHATTR_PROG +C $swapfile >> $seqres.full 2>&1
+$XFS_IO_PROG -f -c "falloc 0 $len" $swapfile >> $seqres.full
 "$here/src/mkswap" $swapfile
 "$here/src/swapon" $swapfile >> $seqres.full 2>&1 || \
 	_notrun "fallocated swap not supported here"

new file mode 100755
index 00000000..665bec39
@@ -0,0 +1,55 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2018 Facebook.  All Rights Reserved.
+#
+# FS QA Test 173
+#
+# Test swap file activation restrictions specific to Btrfs.
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+. ./common/rc
+. ./common/filter
+
+rm -f $seqres.full
+
+_supported_fs generic
+_supported_os Linux
+_require_scratch_swapfile
+
+_scratch_mkfs >> $seqres.full 2>&1
+_scratch_mount
+
+echo "COW file"
+# We can't use _format_swapfile because we don't want chattr +C, and we can't
+# unset it after the swap file has been created.
+rm -f "$SCRATCH_MNT/swap"
+touch "$SCRATCH_MNT/swap"
+chmod 0600 "$SCRATCH_MNT/swap"
+_pwrite_byte 0x61 0 $(($(get_page_size) * 10)) "$SCRATCH_MNT/swap" >> $seqres.full
+mkswap "$SCRATCH_MNT/swap" >> $seqres.full
+swapon "$SCRATCH_MNT/swap" 2>&1 | _filter_scratch
+swapoff "$SCRATCH_MNT/swap" >/dev/null 2>&1
+
+echo "Compressed file"
+rm -f "$SCRATCH_MNT/swap"
+_format_swapfile "$SCRATCH_MNT/swap" $(($(get_page_size) * 10))
+$CHATTR_PROG +c "$SCRATCH_MNT/swap"
+swapon "$SCRATCH_MNT/swap" 2>&1 | _filter_scratch
+swapoff "$SCRATCH_MNT/swap" >/dev/null 2>&1
+
+status=0
+exit

new file mode 100644
index 00000000..6d7856bf
@@ -0,0 +1,5 @@
+QA output created by 173
+COW file
+swapon: SCRATCH_MNT/swap: swapon failed: Invalid argument
+Compressed file
+swapon: SCRATCH_MNT/swap: swapon failed: Invalid argument

index a490d7eb..3525014f 100644
@@ -175,3 +175,4 @@
 170 auto quick snapshot
 171 auto quick qgroup
 172 auto quick punch
+173 auto quick swap

new file mode 100755
index 00000000..a26e6669
@@ -0,0 +1,66 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2018 Facebook.  All Rights Reserved.
+#
+# FS QA Test 174
+#
+# Test restrictions on operations that can be done on an active swap file
+# specific to Btrfs.
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+. ./common/rc
+. ./common/filter
+
+rm -f $seqres.full
+
+_supported_fs generic
+_supported_os Linux
+_require_scratch_swapfile
+
+_scratch_mkfs >> $seqres.full 2>&1
+_scratch_mount
+
+$BTRFS_UTIL_PROG subvol create "$SCRATCH_MNT/swapvol" >> $seqres.full
+swapfile="$SCRATCH_MNT/swapvol/swap"
+_format_swapfile "$swapfile" $(($(get_page_size) * 10))
+swapon "$swapfile"
+
+# Turning off nowcow doesn't do anything because the file is not empty, not
+# because the file is a swap file, but make sure this works anyways.
+echo "Disable nocow"
+$CHATTR_PROG -C "$swapfile"
+lsattr -l "$swapfile" | _filter_scratch | _filter_spaces
+
+# Compression we reject outright.
+echo "Enable compression"
+$CHATTR_PROG +c "$swapfile" 2>&1 | grep -o "Text file busy"
+lsattr -l "$swapfile" | _filter_scratch | _filter_spaces
+
+echo "Snapshot"
+$BTRFS_UTIL_PROG subvol snap "$SCRATCH_MNT/swapvol" \
+	"$SCRATCH_MNT/swapsnap" 2>&1 | grep -o "Text file busy"
+
+echo "Defrag"
+# We pass the -c (compress) flag to force defrag even if the file isn't
+# fragmented.
+$BTRFS_UTIL_PROG filesystem defrag -c "$swapfile" 2>&1 | grep -o "Text file busy"
+
+swapoff "$swapfile"
+_scratch_unmount
+
+status=0
+exit

new file mode 100644
index 00000000..bc24f1fb
@@ -0,0 +1,10 @@
+QA output created by 174
+Disable nocow
+SCRATCH_MNT/swapvol/swap No_COW
+Enable compression
+Text file busy
+SCRATCH_MNT/swapvol/swap No_COW
+Snapshot
+Text file busy
+Defrag
+Text file busy

index 3525014f..2e10f7df 100644
@@ -176,3 +176,4 @@
 171 auto quick qgroup
 172 auto quick punch
 173 auto quick swap
+174 auto quick swap

new file mode 100755
index 00000000..64afc4f0
@@ -0,0 +1,73 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2018 Facebook.  All Rights Reserved.
+#
+# FS QA Test 175
+#
+# Test swap file activation on multiple devices.
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+. ./common/rc
+. ./common/filter
+
+rm -f $seqres.full
+
+_supported_fs generic
+_supported_os Linux
+_require_scratch_dev_pool 2
+_require_scratch_swapfile
+
+cycle_swapfile() {
+	local sz=${1:-$(($(get_page_size) * 10))}
+	_format_swapfile "$SCRATCH_MNT/swap" "$sz"
+	swapon "$SCRATCH_MNT/swap" 2>&1 | _filter_scratch
+	swapoff "$SCRATCH_MNT/swap" > /dev/null 2>&1
+}
+
+echo "RAID 1"
+_scratch_pool_mkfs -d raid1 -m raid1 >> $seqres.full 2>&1
+_scratch_mount
+cycle_swapfile
+_scratch_unmount
+
+echo "DUP"
+_scratch_pool_mkfs -d dup -m dup >> $seqres.full 2>&1
+_scratch_mount
+cycle_swapfile
+_scratch_unmount
+
+echo "Single on multiple devices"
+_scratch_pool_mkfs -d single -m raid1 -b $((1024 * 1024 * 1024)) >> $seqres.full 2>&1
+_scratch_mount
+# Each device is only 1 GB, so 1.5 GB must be split across multiple devices.
+cycle_swapfile $((3 * 1024 * 1024 * 1024 / 2))
+_scratch_unmount
+
+echo "Single on one device"
+_scratch_mkfs >> $seqres.full 2>&1
+_scratch_mount
+# Create the swap file, then add the device. That way we know it's all on one
+# device.
+_format_swapfile "$SCRATCH_MNT/swap" $(($(get_page_size) * 10))
+scratch_dev2="$(echo "${SCRATCH_DEV_POOL}" | awk '{ print $2 }')"
+$BTRFS_UTIL_PROG device add -f "$scratch_dev2" "$SCRATCH_MNT"
+swapon "$SCRATCH_MNT/swap" 2>&1 | _filter_scratch
+swapoff "$SCRATCH_MNT/swap" > /dev/null 2>&1
+_scratch_unmount
+
+status=0
+exit

new file mode 100644
index 00000000..ce2e5992
@@ -0,0 +1,8 @@
+QA output created by 175
+RAID 1
+swapon: SCRATCH_MNT/swap: swapon failed: Invalid argument
+DUP
+swapon: SCRATCH_MNT/swap: swapon failed: Invalid argument
+Single on multiple devices
+swapon: SCRATCH_MNT/swap: swapon failed: Invalid argument
+Single on one device

index 2e10f7df..b6160b72 100644
@@ -177,3 +177,4 @@
 172 auto quick punch
 173 auto quick swap
 174 auto quick swap
+175 auto quick swap

new file mode 100755
index 00000000..1e576149
@@ -0,0 +1,82 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2018 Facebook.  All Rights Reserved.
+#
+# FS QA Test 176
+#
+# Test device remove/replace with an active swap file.
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs generic
+_supported_os Linux
+_require_scratch_dev_pool 3
+_require_scratch_swapfile
+
+# We check the filesystem manually because we move devices around.
+rm -f "${RESULT_DIR}/require_scratch"
+
+scratch_dev1="$(echo "${SCRATCH_DEV_POOL}" | awk '{ print $1 }')"
+scratch_dev2="$(echo "${SCRATCH_DEV_POOL}" | awk '{ print $2 }')"
+scratch_dev3="$(echo "${SCRATCH_DEV_POOL}" | awk '{ print $3 }')"
+
+echo "Remove device"
+_scratch_mkfs >> $seqres.full 2>&1
+_scratch_mount
+_format_swapfile "$SCRATCH_MNT/swap" $(($(get_page_size) * 10))
+$BTRFS_UTIL_PROG device add -f "$scratch_dev2" "$SCRATCH_MNT"
+swapon "$SCRATCH_MNT/swap" 2>&1 | _filter_scratch
+# We know the swap file is on device 1 because we added device 2 after it was
+# already created.
+$BTRFS_UTIL_PROG device delete "$scratch_dev1" "$SCRATCH_MNT" 2>&1 | grep -o "Text file busy"
+# Deleting/readding device 2 should still work.
+$BTRFS_UTIL_PROG device delete "$scratch_dev2" "$SCRATCH_MNT"
+$BTRFS_UTIL_PROG device add -f "$scratch_dev2" "$SCRATCH_MNT"
+swapoff "$SCRATCH_MNT/swap" > /dev/null 2>&1
+# Deleting device 1 should work again after swapoff.
+$BTRFS_UTIL_PROG device delete "$scratch_dev1" "$SCRATCH_MNT"
+_scratch_unmount
+_check_scratch_fs "$scratch_dev2"
+
+echo "Replace device"
+_scratch_mkfs >> $seqres.full 2>&1
+_scratch_mount
+_format_swapfile "$SCRATCH_MNT/swap" $(($(get_page_size) * 10))
+$BTRFS_UTIL_PROG device add -f "$scratch_dev2" "$SCRATCH_MNT"
+swapon "$SCRATCH_MNT/swap" 2>&1 | _filter_scratch
+# Again, we know the swap file is on device 1.
+$BTRFS_UTIL_PROG replace start -fB "$scratch_dev1" "$scratch_dev3" "$SCRATCH_MNT" 2>&1 | grep -o "Text file busy"
+# Replacing device 2 should still work.
+$BTRFS_UTIL_PROG replace start -fB "$scratch_dev2" "$scratch_dev3" "$SCRATCH_MNT"
+swapoff "$SCRATCH_MNT/swap" > /dev/null 2>&1
+# Replacing device 1 should work again after swapoff.
+$BTRFS_UTIL_PROG replace start -fB "$scratch_dev1" "$scratch_dev2" "$SCRATCH_MNT"
+_scratch_unmount
+_check_scratch_fs "$scratch_dev2"
+
+# success, all done
+status=0
+exit

new file mode 100644
index 00000000..5c99e0fd
@@ -0,0 +1,5 @@
+QA output created by 176
+Remove device
+Text file busy
+Replace device
+Text file busy

index b6160b72..3562420b 100644
@@ -178,3 +178,4 @@
 173 auto quick swap
 174 auto quick swap
 175 auto quick swap
+176 auto quick swap

new file mode 100755
index 00000000..12dad8fc
@@ -0,0 +1,64 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2018 Facebook.  All Rights Reserved.
+#
+# FS QA Test 177
+#
+# Test relocation (balance and resize) with an active swap file.
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+. ./common/rc
+. ./common/filter
+. ./common/btrfs
+
+rm -f $seqres.full
+
+# Modify as appropriate.
+_supported_fs generic
+_supported_os Linux
+_require_scratch_swapfile
+
+swapfile="$SCRATCH_MNT/swap"
+
+# First, create a 1GB filesystem and fill it up.
+_scratch_mkfs_sized $((1024 * 1024 * 1024)) >> $seqres.full 2>&1
+_scratch_mount
+dd if=/dev/zero of="$SCRATCH_MNT/fill" bs=1024k >> $seqres.full 2>&1
+# Now add more space and create a swap file. We know that the first 1GB of the
+# filesystem was used, so the swap file must be in the new part of the
+# filesystem.
+$BTRFS_UTIL_PROG filesystem resize 2G "$SCRATCH_MNT" | _filter_scratch
+_format_swapfile "$swapfile" $((32 * 1024 * 1024))
+swapon "$swapfile"
+# Add even more space which we know is unused.
+$BTRFS_UTIL_PROG filesystem resize 3G "$SCRATCH_MNT" | _filter_scratch
+# Free up the first 1GB of the filesystem.
+rm -f "$SCRATCH_MNT/fill"
+# Get rid of empty block groups and also make sure that balance skips block
+# groups containing active swap files.
+_run_btrfs_balance_start "$SCRATCH_MNT"
+# Shrink away the unused space.
+$BTRFS_UTIL_PROG filesystem resize 2G "$SCRATCH_MNT" | _filter_scratch
+# Try to shrink away the area occupied by the swap file, which should fail.
+$BTRFS_UTIL_PROG filesystem resize 1G "$SCRATCH_MNT" 2>&1 | grep -o "Text file busy"
+swapoff "$swapfile"
+# It should work again after swapoff.
+$BTRFS_UTIL_PROG filesystem resize 1G "$SCRATCH_MNT" | _filter_scratch
+_scratch_unmount
+
+status=0
+exit

new file mode 100644
index 00000000..6ced01da
@@ -0,0 +1,6 @@
+QA output created by 177
+Resize 'SCRATCH_MNT' of '2G'
+Resize 'SCRATCH_MNT' of '3G'
+Resize 'SCRATCH_MNT' of '2G'
+Text file busy
+Resize 'SCRATCH_MNT' of '1G'

index 3562420b..0b62e58a 100644
@@ -179,3 +179,4 @@
 174 auto quick swap
 175 auto quick swap
 176 auto quick swap
+177 auto quick swap