Re: [PATCH 06/11] xfs: Check for extent overflow when adding/removing dir entries

Darrick J. Wong
2020-11-14T00:38:33Z

On Fri, Nov 13, 2020 at 04:56:58PM +0530, Chandan Babu R wrote:
> This test verifies that XFS does not cause inode fork's extent count to
> overflow when adding/removing directory entries.
>
> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
> ---
> tests/xfs/526 | 360 ++++++++++++++++++++++++++++++++++++++++++++++
> tests/xfs/526.out | 47 ++++++
> tests/xfs/group | 1 +
> 3 files changed, 408 insertions(+)
> create mode 100755 tests/xfs/526
> create mode 100644 tests/xfs/526.out
>
> diff --git a/tests/xfs/526 b/tests/xfs/526
> new file mode 100755
> index 00000000..39cfbcf8
> --- /dev/null
> +++ b/tests/xfs/526
> @@ -0,0 +1,360 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2020 Chandan Babu R. All Rights Reserved.
> +#
> +# FS QA Test 526
> +#
> +# Verify that XFS does not cause inode fork's extent count to overflow when
> +# adding/removing directory entries.
> +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
> +. ./common/inject
> +
> +# remove previous $seqres.full before test
> +rm -f $seqres.full
> +
> +# real QA test starts here
> +
> +_supported_fs xfs
> +_require_scratch
> +_require_xfs_debug
> +_require_test_program "punch-alternating"
> +_require_xfs_io_error_injection "reduce_max_iextents"
> +_require_xfs_io_error_injection "bmap_alloc_minlen_extent"
> +
> +_scratch_mkfs_sized $((1024 * 1024 * 1024)) | _filter_mkfs >> $seqres.full 2> $tmp.mkfs
> +. $tmp.mkfs
> +
> +dir_entry_create()
> +{
> + echo "* Create directory entries"
> +
> + echo "Format and mount fs"
> + _scratch_mkfs_sized $((1024 * 1024 * 1024)) >> $seqres.full
> + _scratch_mount >> $seqres.full

Same questions as I've had for all the other tests -- why is it critical to
reformat between each test? Why is it necessary to encode uuids in the
attr/dir names?

> +
> + testfile=$SCRATCH_MNT/testfile
> +
> + echo "Consume free space"
> + dd if=/dev/zero of=${testfile} bs=${dbsize} >> $seqres.full 2>&1
> + sync
> +
> + echo "Create fragmented filesystem"
> + $here/src/punch-alternating $testfile >> $seqres.full
> + sync
> +
> + echo "Inject reduce_max_iextents error tag"
> + xfs_io -x -c 'inject reduce_max_iextents' $SCRATCH_MNT
> +
> + echo "Inject bmap_alloc_minlen_extent error tag"
> + xfs_io -x -c 'inject bmap_alloc_minlen_extent' $SCRATCH_MNT
> +
> + echo "Create directory entries"
> + dent_len=$(uuidgen | wc -c)

Also, it'll explode the directories faster if you use maximal length
names (255) instead of uuids (37).

The same applies to the xattr tests in the previous patch.

> + nr_dents=$((dbsize * 20 / dent_len))
> + for i in $(seq 1 $nr_dents); do
> + touch $SCRATCH_MNT/$(uuidgen) >> $seqres.full 2>&1 || break
> + done
> +
> + dirino=$(stat -c "%i" $SCRATCH_MNT)
> +
> + _scratch_unmount >> $seqres.full
> +
> + echo "Verify directory's extent count"
> +
> + nextents=$(_scratch_get_iext_count $dirino data || \
> + _fail "Unable to obtain inode fork's extent count")
> + if (( $nextents > 10 )); then
> + echo "Extent count overflow check failed: nextents = $nextents"
> + fi
> +}
> +
> +dir_entry_rename_dst()
> +{
> + echo "* Rename: Populate destination directory"
> +
> + echo "Format and mount fs"
> + _scratch_mkfs_sized $((1024 * 1024 * 1024)) >> $seqres.full
> + _scratch_mount >> $seqres.full
> +
> + testfile=$SCRATCH_MNT/testfile
> +
> + echo "Consume free space"
> + dd if=/dev/zero of=${testfile} bs=${dbsize} >> $seqres.full 2>&1
> + sync
> +
> + echo "Create fragmented filesystem"
> + $here/src/punch-alternating $testfile >> $seqres.full
> + sync
> +
> + echo "Inject reduce_max_iextents error tag"
> + xfs_io -x -c 'inject reduce_max_iextents' $SCRATCH_MNT
> +
> + echo "Inject bmap_alloc_minlen_extent error tag"
> + xfs_io -x -c 'inject bmap_alloc_minlen_extent' $SCRATCH_MNT
> +
> + dstdir=$SCRATCH_MNT/dstdir
> + mkdir $dstdir
> +
> + dent_len=$(uuidgen | wc -c)
> + nr_dents=$((dirbsize * 20 / dent_len))
> +
> + echo "Populate \$dstdir by mv-ing new directory entries"
> + for i in $(seq 1 $nr_dents); do
> + file=${SCRATCH_MNT}/$(uuidgen)
> + touch $file || break
> + mv $file $dstdir >> $seqres.full 2>&1 || break
> + done
> +
> + dirino=$(stat -c "%i" $dstdir)
> +
> + _scratch_unmount >> $seqres.full
> +
> + echo "Verify \$dstdir's extent count"
> +
> + nextents=$(_scratch_get_iext_count $dirino data || \
> + _fail "Unable to obtain inode fork's extent count")
> + if (( $nextents > 10 )); then
> + echo "Extent count overflow check failed: nextents = $nextents"
> + fi
> +}
> +
> +dir_entry_rename_src()
> +{
> + echo "* Rename: Populate source directory and mv one entry to destination directory"
> +
> + echo "Format and mount fs"
> + _scratch_mkfs_sized $((512 * 1024 * 1024)) >> $seqres.full
> + _scratch_mount >> $seqres.full
> +
> + testfile=$SCRATCH_MNT/testfile
> +
> + echo "Consume free space"
> + dd if=/dev/zero of=${testfile} bs=${dbsize} >> $seqres.full 2>&1
> + sync
> +
> + echo "Create fragmented filesystem"
> + $here/src/punch-alternating $testfile >> $seqres.full
> + sync
> +
> + srcdir=${SCRATCH_MNT}/srcdir
> + dstdir=${SCRATCH_MNT}/dstdir
> +
> + mkdir $srcdir $dstdir
> +
> + dirino=$(stat -c "%i" $srcdir)
> +
> + dent_len=$(uuidgen | wc -c)
> + nr_dents=$((dirbsize / dent_len))
> + nextents=0
> + last=""
> +
> + echo "Populate \$srcdir with atleast 4 extents"
> + while (( $nextents < 4 )); do
> + xfs_io -x -c 'inject bmap_alloc_minlen_extent' $SCRATCH_MNT
> +
> + for i in $(seq 1 $nr_dents); do
> + last=${srcdir}/$(uuidgen)
> + touch $last || break
> + done
> +
> + _scratch_unmount >> $seqres.full
> +
> + nextents=$(_scratch_get_iext_count $dirino data || \
> + _fail "Unable to obtain inode fork's extent count")
> +
> + _scratch_mount >> $seqres.full
> + done
> +
> + echo "Inject reduce_max_iextents error tag"
> + xfs_io -x -c 'inject reduce_max_iextents' $SCRATCH_MNT
> +
> + echo "Move an entry from \$srcdir to trigger -EFBIG"
> + mv $last $dstdir >> $seqres.full 2>&1
> + if [[ $? == 0 ]]; then
> + echo "Moving from \$srcdir to \$dstdir succeeded; Should have failed"
> + fi
> +
> + _scratch_unmount >> $seqres.full
> +}
> +
> +dir_entry_create_hard_links()
> +{
> + echo "* Create multiple hard links to a single file"
> +
> + echo "Format and mount fs"
> + _scratch_mkfs_sized $((512 * 1024 * 1024)) >> $seqres.full
> + _scratch_mount >> $seqres.full
> +
> + testfile=$SCRATCH_MNT/testfile
> +
> + echo "Consume free space"
> + dd if=/dev/zero of=${testfile} bs=${dbsize} >> $seqres.full 2>&1
> + sync
> +
> + echo "Create fragmented filesystem"
> + $here/src/punch-alternating $testfile >> $seqres.full
> + sync
> +
> + echo "Inject reduce_max_iextents error tag"
> + xfs_io -x -c 'inject reduce_max_iextents' $SCRATCH_MNT
> +
> + echo "Inject bmap_alloc_minlen_extent error tag"
> + xfs_io -x -c 'inject bmap_alloc_minlen_extent' $SCRATCH_MNT
> +
> + dent_len=$(uuidgen | wc -c)
> + nr_dents=$((dirbsize * 20 / dent_len))
> +
> + echo "Create multiple hardlinks"
> + for i in $(seq 1 $nr_dents); do
> + ln $testfile ${SCRATCH_MNT}/$(uuidgen) >> $seqres.full 2>&1 || break
> + done
> +
> + dirino=$(stat -c "%i" $SCRATCH_MNT)
> +
> + _scratch_unmount >> $seqres.full
> +
> + echo "Verify directory's extent count"
> +
> + nextents=$(_scratch_get_iext_count $dirino data || \
> + _fail "Unable to obtain inode fork's extent count")
> + if (( $nextents > 10 )); then
> + echo "Extent count overflow check failed: nextents = $nextents"
> + fi
> +}
> +
> +dir_entry_create_symlinks()
> +{
> + echo "* Create multiple symbolic links to a single file"
> +
> + echo "Format and mount fs"
> + _scratch_mkfs_sized $((512 * 1024 * 1024)) >> $seqres.full
> + _scratch_mount >> $seqres.full
> +
> + testfile=$SCRATCH_MNT/testfile
> +
> + echo "Consume free space"
> + dd if=/dev/zero of=${testfile} bs=${dbsize} >> $seqres.full 2>&1
> + sync
> +
> + echo "Create fragmented filesystem"
> + $here/src/punch-alternating $testfile >> $seqres.full
> + sync
> +
> + echo "Inject reduce_max_iextents error tag"
> + xfs_io -x -c 'inject reduce_max_iextents' $SCRATCH_MNT
> +
> + echo "Inject bmap_alloc_minlen_extent error tag"
> + xfs_io -x -c 'inject bmap_alloc_minlen_extent' $SCRATCH_MNT
> +
> + dent_len=$(uuidgen | wc -c)
> + nr_dents=$((dirbsize * 20 / dent_len))
> +
> + echo "Create multiple symbolic links"
> + for i in $(seq 1 $nr_dents); do
> + ln -s $testfile ${SCRATCH_MNT}/$(uuidgen) >> $seqres.full 2>&1 || break;
> + done
> +
> + dirino=$(stat -c "%i" $SCRATCH_MNT)
> +
> + _scratch_unmount >> $seqres.full
> +
> + echo "Verify directory's extent count"
> +
> + nextents=$(_scratch_get_iext_count $dirino data || \
> + _fail "Unable to obtain inode fork's extent count")
> + if (( $nextents > 10 )); then
> + echo "Extent count overflow check failed: nextents = $nextents"
> + fi
> +}
> +
> +dir_entry_remove()
> +{
> + echo "* Populate a directory and remove one entry"
> +
> + echo "Format and mount fs"
> + _scratch_mkfs_sized $((512 * 1024 * 1024)) >> $seqres.full
> + _scratch_mount >> $seqres.full
> +
> + testfile=$SCRATCH_MNT/testfile
> +
> + echo "Consume free space"
> + dd if=/dev/zero of=${testfile} bs=${dbsize} >> $seqres.full 2>&1
> + sync
> +
> + echo "Create fragmented filesystem"
> + $here/src/punch-alternating $testfile >> $seqres.full
> + sync
> +
> + dirino=$(stat -c "%i" $SCRATCH_MNT)
> +
> + dent_len=$(uuidgen | wc -c)
> + nr_dents=$((dirbsize / dent_len))
> + nextents=0
> + last=""
> +
> + echo "Populate directory with atleast 4 extents"
> + while (( $nextents < 4 )); do
> + xfs_io -x -c 'inject bmap_alloc_minlen_extent' $SCRATCH_MNT
> +
> + for i in $(seq 1 $nr_dents); do
> + last=${SCRATCH_MNT}/$(uuidgen)
> + touch $last || break
> + done
> +
> + _scratch_unmount >> $seqres.full
> +
> + nextents=$(_scratch_get_iext_count $dirino data || \
> + _fail "Unable to obtain inode fork's extent count")
> +
> + _scratch_mount >> $seqres.full
> + done
> +
> + echo "Inject reduce_max_iextents error tag"
> + xfs_io -x -c 'inject reduce_max_iextents' $SCRATCH_MNT
> +
> + echo "Remove an entry from directory to trigger -EFBIG"
> + rm $last >> $seqres.full 2>&1
> + if [[ $? == 0 ]]; then
> + echo "Removing file succeeded; Should have failed"
> + fi
> +
> + _scratch_unmount >> $seqres.full
> +}
> +
> +# Filesystems with directory block size greater than one FSB will not be tested,
> +# since "7 (i.e. XFS_DA_NODE_MAXDEPTH + 1 data block + 1 free block) * 2 (fsb
> +# count) = 14" is greater than the pseudo max extent count limit of 10.
> +# Extending the pseudo max limit won't help either. Consider the case where 1
> +# FSB is 1k in size and 1 dir block is 64k in size (i.e. fsb count = 64). In
> +# this case, the pseudo max limit has to be greater than 7 * 64 = 448 extents.
> +if (( $dbsize != $dirbsize )); then
> + _notrun "FSB size ($dbsize) and directory block size ($dirbsize) do not match"

Heh, I had wondered about that. Good that you caught this here!

--D

> +fi
> +
> +dir_entry_create
> +dir_entry_rename_dst
> +dir_entry_rename_src
> +dir_entry_create_hard_links
> +dir_entry_create_symlinks
> +dir_entry_remove
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/xfs/526.out b/tests/xfs/526.out
> new file mode 100644
> index 00000000..21f77cd8
> --- /dev/null
> +++ b/tests/xfs/526.out
> @@ -0,0 +1,47 @@
> +QA output created by 526
> +* Create directory entries
> +Format and mount fs
> +Consume free space
> +Create fragmented filesystem
> +Inject reduce_max_iextents error tag
> +Inject bmap_alloc_minlen_extent error tag
> +Create directory entries
> +Verify directory's extent count
> +* Rename: Populate destination directory
> +Format and mount fs
> +Consume free space
> +Create fragmented filesystem
> +Inject reduce_max_iextents error tag
> +Inject bmap_alloc_minlen_extent error tag
> +Populate $dstdir by mv-ing new directory entries
> +Verify $dstdir's extent count
> +* Rename: Populate source directory and mv one entry to destination directory
> +Format and mount fs
> +Consume free space
> +Create fragmented filesystem
> +Populate $srcdir with atleast 4 extents
> +Inject reduce_max_iextents error tag
> +Move an entry from $srcdir to trigger -EFBIG
> +* Create multiple hard links to a single file
> +Format and mount fs
> +Consume free space
> +Create fragmented filesystem
> +Inject reduce_max_iextents error tag
> +Inject bmap_alloc_minlen_extent error tag
> +Create multiple hardlinks
> +Verify directory's extent count
> +* Create multiple symbolic links to a single file
> +Format and mount fs
> +Consume free space
> +Create fragmented filesystem
> +Inject reduce_max_iextents error tag
> +Inject bmap_alloc_minlen_extent error tag
> +Create multiple symbolic links
> +Verify directory's extent count
> +* Populate a directory and remove one entry
> +Format and mount fs
> +Consume free space
> +Create fragmented filesystem
> +Populate directory with atleast 4 extents
> +Inject reduce_max_iextents error tag
> +Remove an entry from directory to trigger -EFBIG
> diff --git a/tests/xfs/group b/tests/xfs/group
> index bd38aff0..d089797b 100644
> --- a/tests/xfs/group
> +++ b/tests/xfs/group
> @@ -523,3 +523,4 @@
> 523 auto quick realtime growfs
> 524 auto quick punch zero insert collapse
> 525 auto quick attr
> +526 auto quick dir hardlink symlink
> --
> 2.28.0
>