Addition of new tests for extsize hints

index 2ee46e51..f94bee5e 100644
@@ -41,6 +41,13 @@ _md5_checksum()
 	md5sum $1 | cut -d ' ' -f1
 }
 
+# Check whether a fsxattr xflags name ($2) field is set on a given file ($1).
+# e.g, fsxattr.xflags =  0x80000800 [extsize, has-xattr]
+_test_fsxattr_xflag()
+{
+	grep -q "fsxattr.xflags.*\[.*$2.*\]" <($XFS_IO_PROG -c "stat -v" "$1")
+}
+
 # Write a byte into a range of a file
 _pwrite_byte() {
 	local pattern="$1"

index bbe21307..394e7e55 100755
@@ -21,15 +21,6 @@ _require_cp_reflink
 _require_xfs_io_command "fiemap"
 _require_xfs_io_command "cowextsize"
 
-# Takes the fsxattr.xflags line,
-# i.e. fsxattr.xflags = 0x0 [--------------C-]
-# and tests whether a flag character is set
-test_xflag()
-{
-    local flg=$1
-    grep -q "\[.*${flg}.*\]" && echo "$flg flag set" || echo "$flg flag unset"
-}
-
 echo "Format and mount"
 _scratch_mkfs > $seqres.full 2>&1
 _scratch_mount >> $seqres.full 2>&1

@@ -65,14 +56,16 @@ echo "Set cowextsize and check flag"
 $XFS_IO_PROG -c "cowextsize 1048576" $testdir/file3 | _filter_scratch
 _scratch_cycle_mount
 
-$XFS_IO_PROG -c "stat" $testdir/file3 | grep 'fsxattr.xflags' | test_xflag "C"
+_test_fsxattr_xflag "$testdir/file3" "cowextsize" && echo "C flag set" || \
+	echo "C flag unset"
 $XFS_IO_PROG -c "cowextsize" $testdir/file3 | _filter_scratch
 
 echo "Unset cowextsize and check flag"
 $XFS_IO_PROG -c "cowextsize 0" $testdir/file3 | _filter_scratch
 _scratch_cycle_mount
 
-$XFS_IO_PROG -c "stat" $testdir/file3 | grep 'fsxattr.xflags' | test_xflag "C"
+_test_fsxattr_xflag "$testdir/file3" "cowextsize" && echo "C flag set" || \
+	echo "C flag unset"
 $XFS_IO_PROG -c "cowextsize" $testdir/file3 | _filter_scratch
 
 status=0

index f94bee5e..e6c6047d 100644
@@ -48,6 +48,23 @@ _test_fsxattr_xflag()
 	grep -q "fsxattr.xflags.*\[.*$2.*\]" <($XFS_IO_PROG -c "stat -v" "$1")
 }
 
+# This test requires extsize support on the  filesystem
+_require_scratch_extsize()
+{
+	_require_scratch
+	_require_xfs_io_command "extsize"
+	_scratch_mkfs > /dev/null
+	_scratch_mount
+	local filename=$SCRATCH_MNT/$RANDOM
+	local blksz=$(_get_block_size $SCRATCH_MNT)
+	local extsz=$(( blksz*2 ))
+	local res=$($XFS_IO_PROG -c "open -f $filename" -c "extsize $extsz" \
+		-c "extsize")
+	_scratch_unmount
+	grep -q "\[$extsz\] $filename" <(echo $res) || \
+		_notrun "this test requires extsize support on the filesystem"
+}
+
 # Write a byte into a range of a file
 _pwrite_byte() {
 	local pattern="$1"

new file mode 100755
index 00000000..7cf90695
@@ -0,0 +1,174 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2024 Nirjhar Roy ([email protected]).  All Rights Reserved.
+#
+# FS QA Test 367
+#
+# This test verifies that extent allocation hint setting works correctly on
+# files with no extents allocated and non-empty files which are truncated.
+# It also checks that the  extent hints setting fails with non-empty file
+# i.e, with any file with allocated extents or delayed allocation. We also
+# check if the extsize value and the xflag bit actually got reflected after
+# setting/re-setting the extsize value.
+
+. ./common/config
+. ./common/filter
+. ./common/preamble
+
+_begin_fstest ioctl quick
+
+_fixed_by_kernel_commit 2a492ff66673 \
+	"xfs: Check for delayed allocations before setting extsize"
+
+_require_scratch_extsize
+
+FILE_DATA_SIZE=1M
+
+get_default_extsize()
+{
+    if [ -z $1 ] || [ ! -d $1 ]; then
+        echo "Missing mount point argument for get_default_extsize"
+        exit 1
+    fi
+    $XFS_IO_PROG -c "extsize" "$1" | sed 's/^\[\([0-9]\+\)\].*/\1/'
+}
+
+filter_extsz()
+{
+    sed "s/\[$1\]/\[EXTSIZE\]/g"
+}
+
+setup()
+{
+    _scratch_mkfs >> "$seqres.full"  2>&1
+    _scratch_mount >> "$seqres.full" 2>&1
+    BLKSZ=`_get_block_size $SCRATCH_MNT`
+    DEFAULT_EXTSIZE=`get_default_extsize $SCRATCH_MNT`
+    EXTSIZE=$(( BLKSZ*2 ))
+    # Make sure the new extsize is not the same as the default
+    # extsize so that we can observe it changing
+    [[ "$DEFAULT_EXTSIZE" -eq "$EXTSIZE" ]] && EXTSIZE=$(( BLKSZ*4 ))
+}
+
+read_file_extsize()
+{
+    $XFS_IO_PROG -c "extsize" $1 | _filter_scratch | filter_extsz $2
+}
+
+check_extsz_and_xflag()
+{
+    local filename=$1
+    local extsize=$2
+    read_file_extsize $filename $extsize
+    _test_fsxattr_xflag $filename "extsize" && echo "e flag set" || \
+	    echo "e flag unset"
+}
+
+check_extsz_xflag_across_remount()
+{
+    local filename=$1
+    local extsize=$2
+    _scratch_cycle_mount
+    check_extsz_and_xflag $filename $extsize
+}
+
+# Extsize flag should be cleared when extsize is reset, so this function
+# checks that this behavior is followed.
+reset_extsz_and_recheck_extsz_xflag()
+{
+    local filename=$1
+    echo "Re-setting extsize hint to 0"
+    $XFS_IO_PROG -c "extsize 0" $filename
+    check_extsz_xflag_across_remount $filename "0"
+}
+
+check_extsz_xflag_before_and_after_reset()
+{
+    local filename=$1
+    local extsize=$2
+    check_extsz_xflag_across_remount $filename $extsize
+    reset_extsz_and_recheck_extsz_xflag $filename
+}
+
+test_empty_file()
+{
+    echo "TEST: Set extsize on empty file"
+    local filename=$1
+    $XFS_IO_PROG \
+        -c "open -f $filename" \
+        -c "extsize $EXTSIZE" \
+
+    check_extsz_xflag_before_and_after_reset $filename $EXTSIZE
+    echo
+}
+
+test_data_delayed()
+{
+    echo "TEST: Set extsize on non-empty file with delayed allocation"
+    local filename=$1
+    $XFS_IO_PROG \
+        -c "open -f $filename" \
+        -c "pwrite -q  0 $FILE_DATA_SIZE" \
+        -c "extsize $EXTSIZE" | _filter_scratch
+
+    echo "test for default extsize setting if any"
+    read_file_extsize $filename $DEFAULT_EXTSIZE
+    echo
+}
+
+test_data_allocated()
+{
+    echo "TEST: Set extsize on non-empty file with allocated extents"
+    local filename=$1
+    $XFS_IO_PROG \
+        -c "open -f $filename" \
+        -c "pwrite -qW  0 $FILE_DATA_SIZE" \
+        -c "extsize $EXTSIZE" | _filter_scratch
+
+    echo "test for default extsize setting if any"
+    read_file_extsize $filename $DEFAULT_EXTSIZE
+    echo
+}
+
+test_truncate_allocated()
+{
+    echo "TEST: Set extsize after truncating a file with allocated extents"
+    local filename=$1
+    $XFS_IO_PROG \
+        -c "open -f $filename" \
+        -c "pwrite -qW  0 $FILE_DATA_SIZE" \
+        -c "truncate 0" \
+        -c "extsize $EXTSIZE" \
+
+    check_extsz_xflag_across_remount $filename $EXTSIZE
+    echo
+}
+
+test_truncate_delayed()
+{
+    echo "TEST: Set extsize after truncating a file with delayed allocation"
+    local filename=$1
+    $XFS_IO_PROG \
+        -c "open -f $filename" \
+        -c "pwrite -q  0 $FILE_DATA_SIZE" \
+        -c "truncate 0" \
+        -c "extsize $EXTSIZE" \
+
+    check_extsz_xflag_across_remount $filename $EXTSIZE
+    echo
+}
+
+setup
+echo -e "EXTSIZE = $EXTSIZE DEFAULT_EXTSIZE = $DEFAULT_EXTSIZE \
+	BLOCKSIZE = $BLKSZ\n" >> "$seqres.full"
+
+NEW_FILE_NAME_PREFIX=$SCRATCH_MNT/new-file-
+
+test_empty_file "$NEW_FILE_NAME_PREFIX"00
+test_data_delayed "$NEW_FILE_NAME_PREFIX"01
+test_data_allocated "$NEW_FILE_NAME_PREFIX"02
+test_truncate_allocated "$NEW_FILE_NAME_PREFIX"03
+test_truncate_delayed "$NEW_FILE_NAME_PREFIX"04
+
+status=0
+exit

new file mode 100644
index 00000000..f94e8545
@@ -0,0 +1,26 @@
+QA output created by 367
+TEST: Set extsize on empty file
+[EXTSIZE] SCRATCH_MNT/new-file-00
+e flag set
+Re-setting extsize hint to 0
+[EXTSIZE] SCRATCH_MNT/new-file-00
+e flag unset
+
+TEST: Set extsize on non-empty file with delayed allocation
+xfs_io: FS_IOC_FSSETXATTR SCRATCH_MNT/new-file-01: Invalid argument
+test for default extsize setting if any
+[EXTSIZE] SCRATCH_MNT/new-file-01
+
+TEST: Set extsize on non-empty file with allocated extents
+xfs_io: FS_IOC_FSSETXATTR SCRATCH_MNT/new-file-02: Invalid argument
+test for default extsize setting if any
+[EXTSIZE] SCRATCH_MNT/new-file-02
+
+TEST: Set extsize after truncating a file with allocated extents
+[EXTSIZE] SCRATCH_MNT/new-file-03
+e flag set
+
+TEST: Set extsize after truncating a file with delayed allocation
+[EXTSIZE] SCRATCH_MNT/new-file-04
+e flag set
+