[PATCH v4 0/4] mkfs: Fix minimal device check so that reported

[PATCH v4 0/4] mkfs: Fix minimal device check so that reported

[Qu Wenruo]

Original reported by Wesley AC:
https://github.com/kdave/btrfs-progs/issues/70

Fix it by taking data/meta profile and minimal chunk size into
consideration.

Also introduce a test case for that.

Changelog:
v2:
  Refactor test_minimum_size() to take @min_dev_size directly. Refactor
  patch already in devel branch.
v3:
  Split test/common modification into separate patch.
v4:
  Further split run_mustfail_stdout() and prepare_test_dev()
  modification into separate patch.
  Include the real mkfs fix into patchset, to prevent possible test
  failure.
  Use suggestion from David to use run_check_mount_test_dev() and
  run_check_umount_test_dev().
  Add "-b $good_size" to mkfs command line, so we can see the size in
  test result, to help further debugging.

Qu Wenruo (4):
  btrfs-progs: mkfs: Enhance minimal device size calculation to fix mkfs
    failure on small file
  btrfs-progs: test/common: Introduce run_mustfail_stdout
  btrfs-progs: test/common: Enhance prepare_test_dev to reset device
    size
  btrfs-progs: test/mkfs: Test if the minimal device size is valid

 mkfs/common.c                            | 68 ++++++++++++++++++++++++++++----
 mkfs/common.h                            |  4 +-
 mkfs/main.c                              |  3 +-
 tests/common                             | 58 ++++++++++++++++++++++++++-
 tests/mkfs-tests/010-small-image/test.sh | 49 +++++++++++++++++++++++
 5 files changed, 171 insertions(+), 11 deletions(-)
 create mode 100755 tests/mkfs-tests/010-small-image/test.sh

-- 
2.14.3

[PATCH v4 1/4] btrfs-progs: mkfs: Enhance minimal device size calculation to fix mkfs failure on small file

[Qu Wenruo]

Since commit c11e36a29e84 ("Btrfs-progs: Do not force mixed block group
creation unless '-M' option is specified"), mkfs no longer use mixed
block group unless specified manually.

This breaks the minimal device size calculation, which only considered
mixed block group use case.

This patch enhances minimal device size calculation for mkfs, by using
different minimal stripe length (calculated from code) for different
profiles, and use them to calculate minimal device size.

Reported-by: Wesley Aptekar-Cassels <W.Aptekar@gmail.com>
Fixes: c11e36a29e84 ("Btrfs-progs: Do not force mixed block group creation unless '-M' option is specified")
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
---
 mkfs/common.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++++------
 mkfs/common.h |  4 ++--
 mkfs/main.c   |  3 ++-
 3 files changed, 65 insertions(+), 10 deletions(-)

diff --git a/mkfs/common.c b/mkfs/common.c
index 71318b10fa51..2c400f44dbf3 100644
--- a/mkfs/common.c
+++ b/mkfs/common.c
@@ -438,12 +438,6 @@ out:
 	return ret;
 }
 
-u64 btrfs_min_dev_size(u32 nodesize)
-{
-	return 2 * (BTRFS_MKFS_SYSTEM_GROUP_SIZE +
-		    btrfs_min_global_blk_rsv_size(nodesize));
-}
-
 /*
  * Btrfs minimum size calculation is complicated, it should include at least:
  * 1. system group size
@@ -454,11 +448,71 @@ u64 btrfs_min_dev_size(u32 nodesize)
  * To avoid the overkill calculation, (system group + global block rsv) * 2
  * for *EACH* device should be good enough.
  */
-u64 btrfs_min_global_blk_rsv_size(u32 nodesize)
+static u64 btrfs_min_global_blk_rsv_size(u32 nodesize)
 {
 	return (u64)nodesize << 10;
 }
 
+u64 btrfs_min_dev_size(u32 nodesize, int mixed, u64 meta_profile,
+		       u64 data_profile)
+{
+	u64 reserved = 0;
+	u64 meta_size;
+	u64 data_size;
+
+	if (mixed)
+		return 2 * (BTRFS_MKFS_SYSTEM_GROUP_SIZE +
+			    btrfs_min_global_blk_rsv_size(nodesize));
+
+	/*
+	 * minimal size calculation is complex due to several factors:
+	 * 1) Temporary chunk resue
+	 *    If specified chunk profile is SINGLE, we can resue
+	 *    temporary chunks, no need to alloc new chunks.
+	 *
+	 * 2) Different minimal chunk size for different profile
+	 *    For initial sys chunk, chunk size is fixed to 4M.
+	 *    For single profile, minimal chunk size is 8M for all.
+	 *    For other profiles, minimal chunk and stripe size
+	 *    differs from 8M to 64M.
+	 *
+	 * To calculate it a little easier, here we assume we don't
+	 * reuse any temporary chunk, and calculate the size all
+	 * by ourselves.
+	 *
+	 * Temporary chunks sizes are always fixed:
+	 * One initial sys chunk, one SINGLE meta, and one SINGLE data.
+	 * The latter two are all 8M, accroding to @calc_size of
+	 * btrfs_alloc_chunk().
+	 */
+	reserved += BTRFS_MKFS_SYSTEM_GROUP_SIZE + SZ_8M * 2;
+
+	/*
+	 * For real chunks, we need to refer different sizes:
+	 * For SINGLE, it's still fixed to 8M (@calc_size).
+	 * For other profiles, refer to max(@min_stripe_size, @calc_size).
+	 *
+	 * And use the stripe size to calculate its physical used space.
+	 */
+	if (meta_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
+		meta_size = SZ_8M + SZ_32M;
+	else
+		meta_size = SZ_8M + SZ_8M;
+	/* Only metadata put 2 stripes into one disk */
+	if (meta_profile & BTRFS_BLOCK_GROUP_DUP)
+		meta_size *= 2;
+	reserved += meta_size;
+
+	if (data_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
+		data_size = SZ_64M;
+	else
+		data_size = SZ_8M;
+	if (data_profile & BTRFS_BLOCK_GROUP_DUP)
+		data_size *= 2;
+	reserved += data_size;
+	return reserved;
+}
+
 #define isoctal(c)	(((c) & ~7) == '0')
 
 static inline void translate(char *f, char *t)
diff --git a/mkfs/common.h b/mkfs/common.h
index 3757e9e7fd0a..e9e3b3eb43a6 100644
--- a/mkfs/common.h
+++ b/mkfs/common.h
@@ -66,8 +66,8 @@ struct btrfs_mkfs_config {
 };
 
 int make_btrfs(int fd, struct btrfs_mkfs_config *cfg);
-u64 btrfs_min_dev_size(u32 nodesize);
-u64 btrfs_min_global_blk_rsv_size(u32 nodesize);
+u64 btrfs_min_dev_size(u32 nodesize, int mixed, u64 meta_profile,
+		       u64 data_profile);
 int test_minimum_size(const char *file, u64 min_dev_size);
 int is_vol_small(const char *file);
 int test_num_disk_vs_raid(u64 metadata_profile, u64 data_profile,
diff --git a/mkfs/main.c b/mkfs/main.c
index 6669a4b901af..982cafc07b84 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -979,7 +979,8 @@ int main(int argc, char **argv)
 		goto error;
 	}
 
-	min_dev_size = btrfs_min_dev_size(nodesize);
+	min_dev_size = btrfs_min_dev_size(nodesize, mixed, metadata_profile,
+					  data_profile);
 	/* Check device/block_count after the nodesize is determined */
 	if (block_count && block_count < min_dev_size) {
 		error("size %llu is too small to make a usable filesystem",
-- 
2.14.3

[PATCH v4 2/4] btrfs-progs: test/common: Introduce run_mustfail_stdout

[Qu Wenruo]

For later test case which needs info from stderr.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 tests/common | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/tests/common b/tests/common
index dec090fe5849..977bade201a6 100644
--- a/tests/common
+++ b/tests/common
@@ -236,6 +236,58 @@ run_mustfail()
 	fi
 }
 
+# The first parameter is error message to print if it fails, just like
+# run_must_fail().
+# Also we don't use pipefail to avoid disturbing other script, so here we
+# use temporary output file.
+# So it doesn't support pipeline in the @cmd
+run_mustfail_stdout()
+{
+	local spec
+	local ins
+	local cmd
+	local msg
+	local ret
+	local tmp_output
+
+	tmp_output=$(mktemp --tmpdir btrfs-progs-test--mustfail-stdtout.XXXXXX)
+
+	msg="$1"
+	shift
+
+	if _is_file_or_command "$msg"; then
+		echo "ASSERTION FAIL: 1st argument of run_mustfail_stdout must be a message"
+		exit 1
+	fi
+
+	ins=$(_get_spec_ins "$@")
+	spec=$(($ins-1))
+	cmd=$(eval echo "\${$spec}")
+	spec=$(_cmd_spec "${@:$spec}")
+	set -- "${@:1:$(($ins-1))}" $spec "${@: $ins}"
+	echo "############### $@" >> "$RESULTS" 2>&1
+	if [[ $TEST_LOG =~ tty ]]; then echo "CMD(mustfail): $@" > /dev/tty; fi
+	if [ "$1" = 'root_helper' ]; then
+		"$@" 2>&1 > "$tmp_output"
+	else
+		$INSTRUMENT "$@" 2>&1 > "$tmp_output"
+	fi
+	ret=$?
+
+	cat "$tmp_output" >> "$RESULTS"
+	cat "$tmp_output"
+	rm "$tmp_output"
+
+	if [ "$ret" != 0 ]; then
+		echo "failed (expected): $@" >> "$RESULTS"
+		return 0
+	else
+		echo "succeeded (unexpected!): $@" >> "$RESULTS"
+		_fail "unexpected success: $msg"
+		return 1
+	fi
+}
+
 check_prereq()
 {
 	if ! [ -f "$TOP/$1" ]; then
-- 
2.14.3

[PATCH v4 3/4] btrfs-progs: test/common: Enhance prepare_test_dev to reset device size

[Qu Wenruo]

So prepare_test_dev() can be called several times in one test case, to
test different device sizes.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 tests/common | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tests/common b/tests/common
index 977bade201a6..63750dbfeffe 100644
--- a/tests/common
+++ b/tests/common
@@ -441,8 +441,12 @@ prepare_test_dev()
 	# num[K/M/G/T...]
 	local size="$1"
 
-	[[ "$TEST_DEV" ]] && return
 	[[ "$size" ]] || size='2G'
+	# Still truncate it to new size
+	if [[ "$TEST_DEV" ]]; then
+		truncate -s "$size" "$TEST_DEV"
+		return;
+	fi
 
 	echo "\$TEST_DEV not given, use $TOP/test/test.img as fallback" >> \
 		"$RESULTS"
-- 
2.14.3

[PATCH v4 4/4] btrfs-progs: test/mkfs: Test if the minimal device size is valid

[Qu Wenruo]

New test case to test if the minimal device size given by "mkfs.btrfs"
failure case is valid.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 tests/mkfs-tests/010-small-image/test.sh | 49 ++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100755 tests/mkfs-tests/010-small-image/test.sh

diff --git a/tests/mkfs-tests/010-small-image/test.sh b/tests/mkfs-tests/010-small-image/test.sh
new file mode 100755
index 000000000000..304c87057304
--- /dev/null
+++ b/tests/mkfs-tests/010-small-image/test.sh
@@ -0,0 +1,49 @@
+#!/bin/bash
+# test if the reported minimal size of mkfs.btrfs is valid
+
+source "$TOP"/tests/common
+
+check_prereq mkfs.btrfs
+check_prereq btrfs
+
+setup_root_helper
+
+do_test()
+{
+	# Well, 1M small enough to fail, we just use the output
+	# to get the minimal device size
+	prepare_test_dev 1M
+	output=$(run_mustfail_stdout "mkfs.btrfs for small image" \
+		 "$TOP"/mkfs.btrfs -f $@ "$TEST_DEV")
+	good_size=$(echo "$output" | grep -oP "(?<=is )\d+")
+
+	prepare_test_dev "$good_size"
+	run_check "$TOP"/mkfs.btrfs -b $good_size -f $@ "$TEST_DEV"
+	run_check_mount_test_dev
+	run_check_umount_test_dev
+}
+
+do_test -n 4k	-m single	-d single
+do_test -n 4k	-m single	-d dup
+do_test -n 4k	-m dup		-d single
+do_test -n 4k	-m dup		-d dup
+
+do_test -n 8k	-m single	-d single
+do_test -n 8k	-m single	-d dup
+do_test -n 8k	-m dup		-d single
+do_test -n 8k	-m dup		-d dup
+
+do_test -n 16k	-m single	-d single
+do_test -n 16k	-m single	-d dup
+do_test -n 16k	-m dup		-d single
+do_test -n 16k	-m dup		-d dup
+
+do_test -n 32k	-m single	-d single
+do_test -n 32k	-m single	-d dup
+do_test -n 32k	-m dup		-d single
+do_test -n 32k	-m dup		-d dup
+
+do_test -n 64k	-m single	-d single
+do_test -n 64k	-m single	-d dup
+do_test -n 64k	-m dup		-d single
+do_test -n 64k	-m dup		-d dup
-- 
2.14.3

Re: [PATCH v4 1/4] btrfs-progs: mkfs: Enhance minimal device size calculation to fix mkfs failure on small file

[David Sterba]

On Wed, Nov 01, 2017 at 09:30:40AM +0800, Qu Wenruo wrote:
> +u64 btrfs_min_dev_size(u32 nodesize, int mixed, u64 meta_profile,
> +		       u64 data_profile)
> +{
> +	u64 reserved = 0;
> +	u64 meta_size;
> +	u64 data_size;
> +
> +	if (mixed)
> +		return 2 * (BTRFS_MKFS_SYSTEM_GROUP_SIZE +
> +			    btrfs_min_global_blk_rsv_size(nodesize));
> +
> +	/*
> +	 * minimal size calculation is complex due to several factors:
> +	 * 1) Temporary chunk resue
> +	 *    If specified chunk profile is SINGLE, we can resue
> +	 *    temporary chunks, no need to alloc new chunks.
> +	 *
> +	 * 2) Different minimal chunk size for different profile
> +	 *    For initial sys chunk, chunk size is fixed to 4M.
> +	 *    For single profile, minimal chunk size is 8M for all.
> +	 *    For other profiles, minimal chunk and stripe size
> +	 *    differs from 8M to 64M.
> +	 *
> +	 * To calculate it a little easier, here we assume we don't
> +	 * reuse any temporary chunk, and calculate the size all
> +	 * by ourselves.
> +	 *
> +	 * Temporary chunks sizes are always fixed:
> +	 * One initial sys chunk, one SINGLE meta, and one SINGLE data.
> +	 * The latter two are all 8M, accroding to @calc_size of
> +	 * btrfs_alloc_chunk().
> +	 */
> +	reserved += BTRFS_MKFS_SYSTEM_GROUP_SIZE + SZ_8M * 2;
> +
> +	/*
> +	 * For real chunks, we need to refer different sizes:
> +	 * For SINGLE, it's still fixed to 8M (@calc_size).
> +	 * For other profiles, refer to max(@min_stripe_size, @calc_size).
> +	 *
> +	 * And use the stripe size to calculate its physical used space.
> +	 */
> +	if (meta_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
> +		meta_size = SZ_8M + SZ_32M;
> +	else
> +		meta_size = SZ_8M + SZ_8M;
> +	/* Only metadata put 2 stripes into one disk */

'mkfs.btrfs -d dup' also works, so I think this should be handled here
the same way as metadata, right?

> +	if (meta_profile & BTRFS_BLOCK_GROUP_DUP)
> +		meta_size *= 2;
> +	reserved += meta_size;
> +
> +	if (data_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
> +		data_size = SZ_64M;
> +	else
> +		data_size = SZ_8M;
> +	if (data_profile & BTRFS_BLOCK_GROUP_DUP)
> +		data_size *= 2;
> +	reserved += data_size;
> +	return reserved;
> +}

Re: [PATCH v4 2/4] btrfs-progs: test/common: Introduce run_mustfail_stdout

[David Sterba]

On Wed, Nov 01, 2017 at 09:30:41AM +0800, Qu Wenruo wrote:
> For later test case which needs info from stderr.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Applied, thanks.

Re: [PATCH v4 3/4] btrfs-progs: test/common: Enhance prepare_test_dev to reset device size

[David Sterba]

On Wed, Nov 01, 2017 at 09:30:42AM +0800, Qu Wenruo wrote:
> So prepare_test_dev() can be called several times in one test case, to
> test different device sizes.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Applied, thanks.

Re: [PATCH v4 1/4] btrfs-progs: mkfs: Enhance minimal device size calculation to fix mkfs failure on small file

[Qu Wenruo]

[-- Attachment #1.1: Type: text/plain, Size: 2798 bytes --]



On 2017年11月28日 07:21, David Sterba wrote:
> On Wed, Nov 01, 2017 at 09:30:40AM +0800, Qu Wenruo wrote:
>> +u64 btrfs_min_dev_size(u32 nodesize, int mixed, u64 meta_profile,
>> +		       u64 data_profile)
>> +{
>> +	u64 reserved = 0;
>> +	u64 meta_size;
>> +	u64 data_size;
>> +
>> +	if (mixed)
>> +		return 2 * (BTRFS_MKFS_SYSTEM_GROUP_SIZE +
>> +			    btrfs_min_global_blk_rsv_size(nodesize));
>> +
>> +	/*
>> +	 * minimal size calculation is complex due to several factors:
>> +	 * 1) Temporary chunk resue
>> +	 *    If specified chunk profile is SINGLE, we can resue
>> +	 *    temporary chunks, no need to alloc new chunks.
>> +	 *
>> +	 * 2) Different minimal chunk size for different profile
>> +	 *    For initial sys chunk, chunk size is fixed to 4M.
>> +	 *    For single profile, minimal chunk size is 8M for all.
>> +	 *    For other profiles, minimal chunk and stripe size
>> +	 *    differs from 8M to 64M.
>> +	 *
>> +	 * To calculate it a little easier, here we assume we don't
>> +	 * reuse any temporary chunk, and calculate the size all
>> +	 * by ourselves.
>> +	 *
>> +	 * Temporary chunks sizes are always fixed:
>> +	 * One initial sys chunk, one SINGLE meta, and one SINGLE data.
>> +	 * The latter two are all 8M, accroding to @calc_size of
>> +	 * btrfs_alloc_chunk().
>> +	 */
>> +	reserved += BTRFS_MKFS_SYSTEM_GROUP_SIZE + SZ_8M * 2;
>> +
>> +	/*
>> +	 * For real chunks, we need to refer different sizes:
>> +	 * For SINGLE, it's still fixed to 8M (@calc_size).
>> +	 * For other profiles, refer to max(@min_stripe_size, @calc_size).
>> +	 *
>> +	 * And use the stripe size to calculate its physical used space.
>> +	 */
>> +	if (meta_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
>> +		meta_size = SZ_8M + SZ_32M;
>> +	else
>> +		meta_size = SZ_8M + SZ_8M;
>> +	/* Only metadata put 2 stripes into one disk */
> 
> 'mkfs.btrfs -d dup' also works, so I think this should be handled here
> the same way as metadata, right?

Just a few lines under.
> 
>> +	if (meta_profile & BTRFS_BLOCK_GROUP_DUP)
>> +		meta_size *= 2;
>> +	reserved += meta_size;
>> +
>> +	if (data_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
>> +		data_size = SZ_64M;
>> +	else
>> +		data_size = SZ_8M;
>> +	if (data_profile & BTRFS_BLOCK_GROUP_DUP)
>> +		data_size *= 2;
Here data DUP is also handled.

So the problem is about the word "Only".

Do I need to re-submit the whole patchset or just a separate patch to
update the comment?

Thanks,
Qu

>> +	reserved += data_size;
>> +	return reserved;
>> +}
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> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 


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Re: [PATCH v4 1/4] btrfs-progs: mkfs: Enhance minimal device size calculation to fix mkfs failure on small file

[David Sterba]

On Tue, Nov 28, 2017 at 08:40:47AM +0800, Qu Wenruo wrote:
> 
> 
> On 2017年11月28日 07:21, David Sterba wrote:
> > On Wed, Nov 01, 2017 at 09:30:40AM +0800, Qu Wenruo wrote:
> >> +u64 btrfs_min_dev_size(u32 nodesize, int mixed, u64 meta_profile,
> >> +		       u64 data_profile)
> >> +{
> >> +	u64 reserved = 0;
> >> +	u64 meta_size;
> >> +	u64 data_size;
> >> +
> >> +	if (mixed)
> >> +		return 2 * (BTRFS_MKFS_SYSTEM_GROUP_SIZE +
> >> +			    btrfs_min_global_blk_rsv_size(nodesize));
> >> +
> >> +	/*
> >> +	 * minimal size calculation is complex due to several factors:
> >> +	 * 1) Temporary chunk resue
> >> +	 *    If specified chunk profile is SINGLE, we can resue
> >> +	 *    temporary chunks, no need to alloc new chunks.
> >> +	 *
> >> +	 * 2) Different minimal chunk size for different profile
> >> +	 *    For initial sys chunk, chunk size is fixed to 4M.
> >> +	 *    For single profile, minimal chunk size is 8M for all.
> >> +	 *    For other profiles, minimal chunk and stripe size
> >> +	 *    differs from 8M to 64M.
> >> +	 *
> >> +	 * To calculate it a little easier, here we assume we don't
> >> +	 * reuse any temporary chunk, and calculate the size all
> >> +	 * by ourselves.
> >> +	 *
> >> +	 * Temporary chunks sizes are always fixed:
> >> +	 * One initial sys chunk, one SINGLE meta, and one SINGLE data.
> >> +	 * The latter two are all 8M, accroding to @calc_size of
> >> +	 * btrfs_alloc_chunk().
> >> +	 */
> >> +	reserved += BTRFS_MKFS_SYSTEM_GROUP_SIZE + SZ_8M * 2;
> >> +
> >> +	/*
> >> +	 * For real chunks, we need to refer different sizes:
> >> +	 * For SINGLE, it's still fixed to 8M (@calc_size).
> >> +	 * For other profiles, refer to max(@min_stripe_size, @calc_size).
> >> +	 *
> >> +	 * And use the stripe size to calculate its physical used space.
> >> +	 */
> >> +	if (meta_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
> >> +		meta_size = SZ_8M + SZ_32M;
> >> +	else
> >> +		meta_size = SZ_8M + SZ_8M;
> >> +	/* Only metadata put 2 stripes into one disk */
> > 
> > 'mkfs.btrfs -d dup' also works, so I think this should be handled here
> > the same way as metadata, right?
> 
> Just a few lines under.
> > 
> >> +	if (meta_profile & BTRFS_BLOCK_GROUP_DUP)
> >> +		meta_size *= 2;
> >> +	reserved += meta_size;
> >> +
> >> +	if (data_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
> >> +		data_size = SZ_64M;
> >> +	else
> >> +		data_size = SZ_8M;
> >> +	if (data_profile & BTRFS_BLOCK_GROUP_DUP)
> >> +		data_size *= 2;
> Here data DUP is also handled.
> 
> So the problem is about the word "Only".

Yeah, it's confusing when comment does not match the code because it's
not clear what's the actual intention.

> Do I need to re-submit the whole patchset or just a separate patch to
> update the comment?

No, I'll update it myself as it is fairly trivial change.

Re: [PATCH v4 4/4] btrfs-progs: test/mkfs: Test if the minimal device size is valid

[David Sterba]

On Wed, Nov 01, 2017 at 09:30:43AM +0800, Qu Wenruo wrote:
> New test case to test if the minimal device size given by "mkfs.btrfs"
> failure case is valid.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Applied, thanks.