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fstests: Check if a fs can survive random (emulated) power loss

RFC PATCH In review Qu Wenruo 3 participants 10 messages Mar 1, 2018 Device mapper

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Qu Wenruo

author
#0 lore raw

RFC PATCH 1/1 fstests: Check if a fs can survive random (emulated) power loss

This test case is originally designed to expose unexpected corruption for btrfs, where there are several reports about btrfs serious metadata corruption after power loss.

The test case itself will trigger heavy fsstress for the fs, and use dm-flakey to emulate power loss by dropping all later writes.

For btrfs, it should be completely fine, as long as superblock write (FUA write) finishes atomically, since with metadata CoW, superblock either points to old trees or new tress, the fs should be as atomic as superblock.

For journal based filesystems, each metadata update should be journaled, so metadata operation is as atomic as journal updates.

It does show that XFS is doing the best work among the tested filesystems (Btrfs, XFS, ext4), no kernel nor xfs_repair problem at all.

For btrfs, although btrfs check doesn't report any problem, kernel reports some data checksum error, which is a little unexpected as data is CoWed by default, which should be as atomic as superblock. (Unfortunately, still not the exact problem I'm chasing for)

For EXT4, kernel is fine, but later e2fsck reports problem, which may indicates there is still something to be improved.

---
 tests/generic/479     | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/generic/479.out |   2 +
 tests/generic/group   |   1 +
 3 files changed, 112 insertions(+)
 create mode 100755 tests/generic/479
 create mode 100644 tests/generic/479.out
tests/generic/479 new file +109 -0
new file mode 100755
index 00000000..ab530231
@@ -0,0 +1,109 @@
+#! /bin/bash
+# FS QA Test 479
+#
+# Test if a filesystem can survive emulated powerloss.
+#
+# No matter what the solution a filesystem uses (journal or CoW),
+# it should survive unexpected powerloss, without major metadata
+# corruption.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2018 SuSE.  All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#-----------------------------------------------------------------------
+#
+
+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()
+{
+	ps -e | grep fsstress > /dev/null 2>&1
+	while [ $? -eq 0 ]; do
+		$KILLALL_PROG -KILL fsstress > /dev/null 2>&1
+		wait > /dev/null 2>&1
+		ps -e | grep fsstress > /dev/null 2>&1
+	done
+	_unmount_flakey &> /dev/null
+	_cleanup_flakey
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/dmflakey
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs generic
+_supported_os Linux
+_require_scratch
+_require_dm_target flakey
+_require_command "$KILLALL_PROG" "killall"
+
+runtime=$(($TIME_FACTOR * 15))
+loops=$(($LOAD_FACTOR * 4))
+
+for i in $(seq -w $loops); do
+	echo "=== Loop $i: $(date) ===" >> $seqres.full
+
+	_scratch_mkfs >/dev/null 2>&1
+	_init_flakey
+	_mount_flakey
+
+	($FSSTRESS_PROG $FSSTRESS_AVOID -w -d $SCRATCH_MNT -n 1000000 \
+		-p 100 >> $seqres.full &) > /dev/null 2>&1
+
+	sleep $runtime
+
+	# Here we only want to drop all write, don't need to umount the fs
+	_load_flakey_table $FLAKEY_DROP_WRITES
+
+	ps -e | grep fsstress > /dev/null 2>&1
+	while [ $? -eq 0 ]; do
+		$KILLALL_PROG -KILL fsstress > /dev/null 2>&1
+		wait > /dev/null 2>&1
+		ps -e | grep fsstress > /dev/null 2>&1
+	done
+
+	_unmount_flakey
+	_cleanup_flakey
+
+	# Mount the fs to do proper log replay for journal based fs
+	# so later check won't report annoying dirty log and only
+	# report real problem.
+	_scratch_mount
+	_scratch_unmount
+
+	_check_scratch_fs
+done
+
+echo "Silence is golden"
+
+# success, all done
+status=0
+exit
tests/generic/479.out new file +2 -0
new file mode 100644
index 00000000..290f18b3
@@ -0,0 +1,2 @@
+QA output created by 479
+Silence is golden
tests/generic/group +1 -0
index 1e808865..5ce3db1d 100644
@@ -481,3 +481,4 @@
 476 auto rw
 477 auto quick exportfs
 478 auto quick
+479 auto
Signature · 1 line
2.15.1
author
#1 lore raw

PATCH 1/2 fstests: log-writes: Add support to output human readable flags

---
 src/log-writes/log-writes.c | 68 +++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 62 insertions(+), 6 deletions(-)
src/log-writes/log-writes.c +62 -6
index 09391574c4d2..181dabf442de 100644
@@ -120,6 +120,58 @@ int log_discard(struct log *log, struct log_write_entry *entry)
 	return 0;
 }
 
+#define DEFINE_LOG_FLAGS_STR_ENTRY(x)	\
+	{LOG_##x##_FLAG, #x}
+
+struct flags_to_str_entry {
+	u64 flags;
+	const char *str;
+} log_flags_table[] = {
+	DEFINE_LOG_FLAGS_STR_ENTRY(FLUSH),
+	DEFINE_LOG_FLAGS_STR_ENTRY(FUA),
+	DEFINE_LOG_FLAGS_STR_ENTRY(DISCARD),
+	DEFINE_LOG_FLAGS_STR_ENTRY(MARK)
+};
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#define LOG_FLAGS_BUF_SIZE	128
+/*
+ * Convert numeric flags to human readable flags.
+ * @flags:	numeric flags
+ * @buf:	output buffer for human readable string.
+ * 		must have enough space (LOG_FLAGS_BUF_SIZE) to contain all
+ * 		the string
+ */
+static void entry_flags_to_str(u64 flags, char *buf)
+{
+	int empty = 1;
+	int left_len;
+	int i;
+
+	buf[0] = '\0';
+	for (i = 0; i < ARRAY_SIZE(log_flags_table); i++) {
+		if (flags & log_flags_table[i].flags) {
+			if (!empty)
+				strncat(buf, "|", LOG_FLAGS_BUF_SIZE);
+			empty = 0;
+			strncat(buf, log_flags_table[i].str, LOG_FLAGS_BUF_SIZE);
+			flags &= ~log_flags_table[i].flags;
+		}
+	}
+	if (flags) {
+		if (!empty)
+			strncat(buf, "|", LOG_FLAGS_BUF_SIZE);
+		empty = 0;
+		left_len = LOG_FLAGS_BUF_SIZE - strnlen(buf,
+						        LOG_FLAGS_BUF_SIZE);
+		if (left_len > 0)
+			snprintf(buf + strnlen(buf, LOG_FLAGS_BUF_SIZE),
+				 left_len, "UNKNOWN.%llu", flags);
+	}
+	if (empty)
+		strncpy(buf, "NONE", LOG_FLAGS_BUF_SIZE);
+}
+
 /*
  * @log: the log we are replaying.
  * @entry: entry to be replayed.
@@ -179,6 +231,7 @@ int log_replay_next_entry(struct log *log, struct log_write_entry *entry,
 	size_t read_size = read_data ? log->sectorsize :
 		sizeof(struct log_write_entry);
 	char *buf;
+	char flags_buf[LOG_FLAGS_BUF_SIZE];
 	ssize_t ret;
 	off_t offset;
 	int skip = 0;
@@ -210,19 +263,20 @@ int log_replay_next_entry(struct log *log, struct log_write_entry *entry,
 		log->cur_pos += read_size;
 	}
 
+	flags = le64_to_cpu(entry->flags);
+	entry_flags_to_str(flags, flags_buf);
 	skip = log_should_skip(log, entry);
 	if (log_writes_verbose > 1 || (log_writes_verbose && !skip)) {
-		printf("%s %d@%llu: sector %llu, size %llu, flags %llu\n",
+		printf("%s %d@%llu: sector %llu, size %llu, flags %llu(%s)\n",
 		       skip ? "skipping" : "replaying",
 		       (int)log->cur_entry - 1, log->cur_pos / log->sectorsize,
 		       (unsigned long long)le64_to_cpu(entry->sector),
 		       (unsigned long long)size,
-		       (unsigned long long)le64_to_cpu(entry->flags));
+		       (unsigned long long)flags, flags_buf);
 	}
 	if (!size)
 		return 0;
 
-	flags = le64_to_cpu(entry->flags);
 	if (flags & LOG_DISCARD_FLAG)
 		return log_discard(log, entry);
 
@@ -339,6 +393,7 @@ int log_seek_next_entry(struct log *log, struct log_write_entry *entry,
 	size_t read_size = read_data ? log->sectorsize :
 		sizeof(struct log_write_entry);
 	u64 flags;
+	char flags_buf[LOG_FLAGS_BUF_SIZE];
 	ssize_t ret;
 
 	if (log->cur_entry >= log->nr_entries)
@@ -366,14 +421,15 @@ int log_seek_next_entry(struct log *log, struct log_write_entry *entry,
 	} else {
 		log->cur_pos += read_size;
 	}
+	flags = le64_to_cpu(entry->flags);
+	entry_flags_to_str(flags, flags_buf);
 	if (log_writes_verbose > 1)
-		printf("seek entry %d@%llu: %llu, size %llu, flags %llu\n",
+		printf("seek entry %d@%llu: %llu, size %llu, flags %llu(%s)\n",
 		       (int)log->cur_entry - 1, log->cur_pos / log->sectorsize,
 		       (unsigned long long)le64_to_cpu(entry->sector),
 		       (unsigned long long)le64_to_cpu(entry->nr_sectors),
-		       (unsigned long long)le64_to_cpu(entry->flags));
+		       (unsigned long long)flags, flags_buf);
 
-	flags = le64_to_cpu(entry->flags);
 	read_size = le64_to_cpu(entry->nr_sectors) * log->sectorsize;
 	if (!read_size || (flags & LOG_DISCARD_FLAG))
 		return 0;
Signature · 1 line
2.16.2
#2 lore raw

Re: [PATCH 1/2] fstests: log-writes: Add support to output human readable flags

Quoted 50 lines · Qu Wenruo
---
 src/log-writes/log-writes.c | 68 +++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 62 insertions(+), 6 deletions(-)
src/log-writes/log-writes.c +37 -0
index 09391574c4d2..181dabf442de 100644
@@ -120,6 +120,58 @@ int log_discard(struct log *log, struct log_write_entry *entry)
        return 0;
 }
 
+#define DEFINE_LOG_FLAGS_STR_ENTRY(x)  \
+       {LOG_##x##_FLAG, #x}
+
+struct flags_to_str_entry {
+       u64 flags;
+       const char *str;
+} log_flags_table[] = {
+       DEFINE_LOG_FLAGS_STR_ENTRY(FLUSH),
+       DEFINE_LOG_FLAGS_STR_ENTRY(FUA),
+       DEFINE_LOG_FLAGS_STR_ENTRY(DISCARD),
+       DEFINE_LOG_FLAGS_STR_ENTRY(MARK)
+};
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#define LOG_FLAGS_BUF_SIZE     128
+/*
+ * Convert numeric flags to human readable flags.
+ * @flags:     numeric flags
+ * @buf:       output buffer for human readable string.
+ *             must have enough space (LOG_FLAGS_BUF_SIZE) to contain all
+ *             the string
+ */
+static void entry_flags_to_str(u64 flags, char *buf)
+{
+       int empty = 1;
+       int left_len;
+       int i;
+
+       buf[0] = '\0';
+       for (i = 0; i < ARRAY_SIZE(log_flags_table); i++) {
+               if (flags & log_flags_table[i].flags) {
+                       if (!empty)
+                               strncat(buf, "|", LOG_FLAGS_BUF_SIZE);
+                       empty = 0;
+                       strncat(buf, log_flags_table[i].str, LOG_FLAGS_BUF_SIZE);
+                       flags &= ~log_flags_table[i].flags;
+               }

src/log-writes/log-writes.c int log_discard(struct log *log, struct log_write_entry *entry) · line 169

Quoted 10 lines
src/log-writes/log-writes.c +10 -0
+       }
+       if (flags) {
+               if (!empty)
+                       strncat(buf, "|", LOG_FLAGS_BUF_SIZE);
+               empty = 0;
+               left_len = LOG_FLAGS_BUF_SIZE - strnlen(buf,
+                                                       LOG_FLAGS_BUF_SIZE);
+               if (left_len > 0)
+                       snprintf(buf + strnlen(buf, LOG_FLAGS_BUF_SIZE),
+                                left_len, "UNKNOWN.%llu", flags);

I think it is best if all numeric prints of flags used %llx below as well.

Quoted 74 lines
src/log-writes/log-writes.c +15 -7
+       }
+       if (empty)
+               strncpy(buf, "NONE", LOG_FLAGS_BUF_SIZE);
+}
+
 /*
  * @log: the log we are replaying.
  * @entry: entry to be replayed.
@@ -179,6 +231,7 @@ int log_replay_next_entry(struct log *log, struct log_write_entry *entry,
        size_t read_size = read_data ? log->sectorsize :
                sizeof(struct log_write_entry);
        char *buf;
+       char flags_buf[LOG_FLAGS_BUF_SIZE];
        ssize_t ret;
        off_t offset;
        int skip = 0;
@@ -210,19 +263,20 @@ int log_replay_next_entry(struct log *log, struct log_write_entry *entry,
                log->cur_pos += read_size;
        }
 
+       flags = le64_to_cpu(entry->flags);
+       entry_flags_to_str(flags, flags_buf);
        skip = log_should_skip(log, entry);
        if (log_writes_verbose > 1 || (log_writes_verbose && !skip)) {
-               printf("%s %d@%llu: sector %llu, size %llu, flags %llu\n",
+               printf("%s %d@%llu: sector %llu, size %llu, flags %llu(%s)\n",
                       skip ? "skipping" : "replaying",
                       (int)log->cur_entry - 1, log->cur_pos / log->sectorsize,
                       (unsigned long long)le64_to_cpu(entry->sector),
                       (unsigned long long)size,
-                      (unsigned long long)le64_to_cpu(entry->flags));
+                      (unsigned long long)flags, flags_buf);
        }
        if (!size)
                return 0;
 
-       flags = le64_to_cpu(entry->flags);
        if (flags & LOG_DISCARD_FLAG)
                return log_discard(log, entry);
 
@@ -339,6 +393,7 @@ int log_seek_next_entry(struct log *log, struct log_write_entry *entry,
        size_t read_size = read_data ? log->sectorsize :
                sizeof(struct log_write_entry);
        u64 flags;
+       char flags_buf[LOG_FLAGS_BUF_SIZE];
        ssize_t ret;
 
        if (log->cur_entry >= log->nr_entries)
@@ -366,14 +421,15 @@ int log_seek_next_entry(struct log *log, struct log_write_entry *entry,
        } else {
                log->cur_pos += read_size;
        }
+       flags = le64_to_cpu(entry->flags);
+       entry_flags_to_str(flags, flags_buf);
        if (log_writes_verbose > 1)
-               printf("seek entry %d@%llu: %llu, size %llu, flags %llu\n",
+               printf("seek entry %d@%llu: %llu, size %llu, flags %llu(%s)\n",
                       (int)log->cur_entry - 1, log->cur_pos / log->sectorsize,
                       (unsigned long long)le64_to_cpu(entry->sector),
                       (unsigned long long)le64_to_cpu(entry->nr_sectors),
-                      (unsigned long long)le64_to_cpu(entry->flags));
+                      (unsigned long long)flags, flags_buf);
 
-       flags = le64_to_cpu(entry->flags);
        read_size = le64_to_cpu(entry->nr_sectors) * log->sectorsize;
        if (!read_size || (flags & LOG_DISCARD_FLAG))
                return 0;
--

2.16.2

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author
#3 lore raw

PATCH 2/2 fstests: log-writes: Add support for METADATA flag

In reply to Qu Wenruo
---
 src/log-writes/log-writes.c | 3 ++-
 src/log-writes/log-writes.h | 9 +++++----
 2 files changed, 7 insertions(+), 5 deletions(-)
src/log-writes/log-writes.c +2 -1
index 181dabf442de..168fea905ef3 100644
@@ -130,7 +130,8 @@ struct flags_to_str_entry {
 	DEFINE_LOG_FLAGS_STR_ENTRY(FLUSH),
 	DEFINE_LOG_FLAGS_STR_ENTRY(FUA),
 	DEFINE_LOG_FLAGS_STR_ENTRY(DISCARD),
-	DEFINE_LOG_FLAGS_STR_ENTRY(MARK)
+	DEFINE_LOG_FLAGS_STR_ENTRY(MARK),
+	DEFINE_LOG_FLAGS_STR_ENTRY(METADATA)
 };
 
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
src/log-writes/log-writes.h +5 -4
index 35ca35838aac..75fb8ac0bf79 100644
@@ -20,10 +20,11 @@ typedef __u32 u32;
 /*
  * Constants copied from kernel file drivers/md/dm-log-writes.c
  */
-#define LOG_FLUSH_FLAG (1 << 0)
-#define LOG_FUA_FLAG (1 << 1)
-#define LOG_DISCARD_FLAG (1 << 2)
-#define LOG_MARK_FLAG (1 << 3)
+#define LOG_FLUSH_FLAG		(1 << 0)
+#define LOG_FUA_FLAG		(1 << 1)
+#define LOG_DISCARD_FLAG	(1 << 2)
+#define LOG_MARK_FLAG		(1 << 3)
+#define LOG_METADATA_FLAG	(1 << 4)
 
 #define WRITE_LOG_VERSION 1
 #define WRITE_LOG_MAGIC 0x6a736677736872
Signature · 1 line
2.16.2
#4 lore raw
In reply to Qu Wenruo
Quoted 6 lines · Qu Wenruo

This test case is originally designed to expose unexpected corruption for btrfs, where there are several reports about btrfs serious metadata corruption after power loss.

The test case itself will trigger heavy fsstress for the fs, and use dm-flakey to emulate power loss by dropping all later writes.

So you are re-posting the test with dm-flakey or converting it to dm-log-writes??

Quoted 157 lines

For btrfs, it should be completely fine, as long as superblock write (FUA write) finishes atomically, since with metadata CoW, superblock either points to old trees or new tress, the fs should be as atomic as superblock.

For journal based filesystems, each metadata update should be journaled, so metadata operation is as atomic as journal updates.

It does show that XFS is doing the best work among the tested filesystems (Btrfs, XFS, ext4), no kernel nor xfs_repair problem at all.

For btrfs, although btrfs check doesn't report any problem, kernel reports some data checksum error, which is a little unexpected as data is CoWed by default, which should be as atomic as superblock. (Unfortunately, still not the exact problem I'm chasing for)

For EXT4, kernel is fine, but later e2fsck reports problem, which may indicates there is still something to be improved.

---
 tests/generic/479     | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/generic/479.out |   2 +
 tests/generic/group   |   1 +
 3 files changed, 112 insertions(+)
 create mode 100755 tests/generic/479
 create mode 100644 tests/generic/479.out
tests/generic/479 new file +109 -0
new file mode 100755
index 00000000..ab530231
@@ -0,0 +1,109 @@
+#! /bin/bash
+# FS QA Test 479
+#
+# Test if a filesystem can survive emulated powerloss.
+#
+# No matter what the solution a filesystem uses (journal or CoW),
+# it should survive unexpected powerloss, without major metadata
+# corruption.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2018 SuSE.  All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#-----------------------------------------------------------------------
+#
+
+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()
+{
+       ps -e | grep fsstress > /dev/null 2>&1
+       while [ $? -eq 0 ]; do
+               $KILLALL_PROG -KILL fsstress > /dev/null 2>&1
+               wait > /dev/null 2>&1
+               ps -e | grep fsstress > /dev/null 2>&1
+       done
+       _unmount_flakey &> /dev/null
+       _cleanup_flakey
+       cd /
+       rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/dmflakey
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs generic
+_supported_os Linux
+_require_scratch
+_require_dm_target flakey
+_require_command "$KILLALL_PROG" "killall"
+
+runtime=$(($TIME_FACTOR * 15))
+loops=$(($LOAD_FACTOR * 4))
+
+for i in $(seq -w $loops); do
+       echo "=== Loop $i: $(date) ===" >> $seqres.full
+
+       _scratch_mkfs >/dev/null 2>&1
+       _init_flakey
+       _mount_flakey
+
+       ($FSSTRESS_PROG $FSSTRESS_AVOID -w -d $SCRATCH_MNT -n 1000000 \
+               -p 100 >> $seqres.full &) > /dev/null 2>&1
+
+       sleep $runtime
+
+       # Here we only want to drop all write, don't need to umount the fs
+       _load_flakey_table $FLAKEY_DROP_WRITES
+
+       ps -e | grep fsstress > /dev/null 2>&1
+       while [ $? -eq 0 ]; do
+               $KILLALL_PROG -KILL fsstress > /dev/null 2>&1
+               wait > /dev/null 2>&1
+               ps -e | grep fsstress > /dev/null 2>&1
+       done
+
+       _unmount_flakey
+       _cleanup_flakey
+
+       # Mount the fs to do proper log replay for journal based fs
+       # so later check won't report annoying dirty log and only
+       # report real problem.
+       _scratch_mount
+       _scratch_unmount
+
+       _check_scratch_fs
+done
+
+echo "Silence is golden"
+
+# success, all done
+status=0
+exit
tests/generic/479.out new file +2 -0
new file mode 100644
index 00000000..290f18b3
@@ -0,0 +1,2 @@
+QA output created by 479
+Silence is golden
tests/generic/group +0 -0
index 1e808865..5ce3db1d 100644

tests/generic/group line 484

Quoted 4 lines
tests/generic/group +1 -0
@@ -481,3 +481,4 @@
 476 auto rw
 477 auto quick exportfs
 478 auto quick
+479 auto

+ stress

#5 lore raw
Quoted 10 lines · Amir Goldstein
Quoted 6 lines · Qu Wenruo

This test case is originally designed to expose unexpected corruption for btrfs, where there are several reports about btrfs serious metadata corruption after power loss.

The test case itself will trigger heavy fsstress for the fs, and use dm-flakey to emulate power loss by dropping all later writes.

So you are re-posting the test with dm-flakey or converting it to dm-log-writes??

Working on the scripts to allow us to do --find and then replay.

Since for xfs and ext4, their fsck would report false alerts just for dirty journal.

I'm adding new macro to locate next flush and replay to it, then mount it RW before we call fsck.

Or do we have options for those fscks to skip dirty journal?

Thanks,
Qu

Quoted 169 lines
Quoted 158 lines

For btrfs, it should be completely fine, as long as superblock write (FUA write) finishes atomically, since with metadata CoW, superblock either points to old trees or new tress, the fs should be as atomic as superblock.

For journal based filesystems, each metadata update should be journaled, so metadata operation is as atomic as journal updates.

It does show that XFS is doing the best work among the tested filesystems (Btrfs, XFS, ext4), no kernel nor xfs_repair problem at all.

For btrfs, although btrfs check doesn't report any problem, kernel reports some data checksum error, which is a little unexpected as data is CoWed by default, which should be as atomic as superblock. (Unfortunately, still not the exact problem I'm chasing for)

For EXT4, kernel is fine, but later e2fsck reports problem, which may indicates there is still something to be improved.

---
 tests/generic/479     | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/generic/479.out |   2 +
 tests/generic/group   |   1 +
 3 files changed, 112 insertions(+)
 create mode 100755 tests/generic/479
 create mode 100644 tests/generic/479.out
tests/generic/479 new file +109 -0
new file mode 100755
index 00000000..ab530231
@@ -0,0 +1,109 @@
+#! /bin/bash
+# FS QA Test 479
+#
+# Test if a filesystem can survive emulated powerloss.
+#
+# No matter what the solution a filesystem uses (journal or CoW),
+# it should survive unexpected powerloss, without major metadata
+# corruption.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2018 SuSE.  All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#-----------------------------------------------------------------------
+#
+
+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()
+{
+       ps -e | grep fsstress > /dev/null 2>&1
+       while [ $? -eq 0 ]; do
+               $KILLALL_PROG -KILL fsstress > /dev/null 2>&1
+               wait > /dev/null 2>&1
+               ps -e | grep fsstress > /dev/null 2>&1
+       done
+       _unmount_flakey &> /dev/null
+       _cleanup_flakey
+       cd /
+       rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/dmflakey
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs generic
+_supported_os Linux
+_require_scratch
+_require_dm_target flakey
+_require_command "$KILLALL_PROG" "killall"
+
+runtime=$(($TIME_FACTOR * 15))
+loops=$(($LOAD_FACTOR * 4))
+
+for i in $(seq -w $loops); do
+       echo "=== Loop $i: $(date) ===" >> $seqres.full
+
+       _scratch_mkfs >/dev/null 2>&1
+       _init_flakey
+       _mount_flakey
+
+       ($FSSTRESS_PROG $FSSTRESS_AVOID -w -d $SCRATCH_MNT -n 1000000 \
+               -p 100 >> $seqres.full &) > /dev/null 2>&1
+
+       sleep $runtime
+
+       # Here we only want to drop all write, don't need to umount the fs
+       _load_flakey_table $FLAKEY_DROP_WRITES
+
+       ps -e | grep fsstress > /dev/null 2>&1
+       while [ $? -eq 0 ]; do
+               $KILLALL_PROG -KILL fsstress > /dev/null 2>&1
+               wait > /dev/null 2>&1
+               ps -e | grep fsstress > /dev/null 2>&1
+       done
+
+       _unmount_flakey
+       _cleanup_flakey
+
+       # Mount the fs to do proper log replay for journal based fs
+       # so later check won't report annoying dirty log and only
+       # report real problem.
+       _scratch_mount
+       _scratch_unmount
+
+       _check_scratch_fs
+done
+
+echo "Silence is golden"
+
+# success, all done
+status=0
+exit
tests/generic/479.out new file +2 -0
new file mode 100644
index 00000000..290f18b3
@@ -0,0 +1,2 @@
+QA output created by 479
+Silence is golden
tests/generic/group +0 -0
index 1e808865..5ce3db1d 100644

tests/generic/group line 484

Quoted 4 lines
tests/generic/group +1 -0
@@ -481,3 +481,4 @@
 476 auto rw
 477 auto quick exportfs
 478 auto quick
+479 auto

+ stress
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#6 lore raw
Quoted 16 lines · Qu Wenruo
Quoted 10 lines · Amir Goldstein
Quoted 6 lines · Qu Wenruo

This test case is originally designed to expose unexpected corruption for btrfs, where there are several reports about btrfs serious metadata corruption after power loss.

The test case itself will trigger heavy fsstress for the fs, and use dm-flakey to emulate power loss by dropping all later writes.

So you are re-posting the test with dm-flakey or converting it to dm-log-writes??

Working on the scripts to allow us to do --find and then replay.

Quoted 8 lines

Since for xfs and ext4, their fsck would report false alerts just for dirty journal.

I'm adding new macro to locate next flush and replay to it, then mount it RW before we call fsck.

Or do we have options for those fscks to skip dirty journal?

No, you are much better off doing mount/umount before fsck. Even though e2fsck can replay a journal, it does that much slower then the kernel does.

But why do you need to teach --find to find next flush?
You could use a helper script to run every fua with --fsck --check fua. Granted, for fstests context, I agree that --find next fua may look nicer, so I have no objection to this implementation.

Thanks,
Amir.

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https://www.redhat.com/mailman/listinfo/dm-devel

#7 lore raw
Quoted 26 lines · Amir Goldstein
Quoted 16 lines · Qu Wenruo
Quoted 10 lines · Amir Goldstein
Quoted 6 lines · Qu Wenruo

This test case is originally designed to expose unexpected corruption for btrfs, where there are several reports about btrfs serious metadata corruption after power loss.

The test case itself will trigger heavy fsstress for the fs, and use dm-flakey to emulate power loss by dropping all later writes.

So you are re-posting the test with dm-flakey or converting it to dm-log-writes??

Working on the scripts to allow us to do --find and then replay.

Quoted 8 lines

Since for xfs and ext4, their fsck would report false alerts just for dirty journal.

I'm adding new macro to locate next flush and replay to it, then mount it RW before we call fsck.

Or do we have options for those fscks to skip dirty journal?

Quoted 8 lines

No, you are much better off doing mount/umount before fsck. Even though e2fsck can replay a journal, it does that much slower then the kernel does.

But why do you need to teach --find to find next flush?
You could use a helper script to run every fua with --fsck --check fua. Granted, for fstests context, I agree that --find next fua may look nicer, so I have no objection to this implementation.

The point is, in my opinion fua is not the worst case we need to test. Only flush could leads us to the worst case we really need to test.

In btrfs' case, if we finished flush, but without fua, we have a super block points to all old trees, but all new trees are already written to disk.

In that flush entry, we could reach to the worst case scenario to verify all btrfs tricks are working all together to get a completely sane btrfs (even all data should be correct).

This should also apply to journal based filesystems (if I understand the journal thing correctly), even when all journals written but superblock not updated, we should be completely fine.
(Although for journal, we may need to reach fua entry instead of flush?)

And the other reason why we need to find next flush/fua manually is, mount will write new data, and we need to replay all the sequence until next flush/fua.

And finally the reason about why need manually mount is, we need to workaround e2fsck/xfs_repair, so that they won't report dirty journal as error. If we have extra options to disable such behavior, I'm completely OK with current --check flush/fua --fsck method.
(BTW, for my btrfs testing, --check flush --fsck is completely good enough, to exposed possible free space cache related problems)

Thanks,
Qu

Quoted 4 lines

Thanks,
Amir.

#8 lore raw
Quoted 49 lines · Qu Wenruo
Quoted 26 lines · Amir Goldstein
Quoted 16 lines · Qu Wenruo
Quoted 10 lines · Amir Goldstein
Quoted 6 lines · Qu Wenruo

This test case is originally designed to expose unexpected corruption for btrfs, where there are several reports about btrfs serious metadata corruption after power loss.

The test case itself will trigger heavy fsstress for the fs, and use dm-flakey to emulate power loss by dropping all later writes.

So you are re-posting the test with dm-flakey or converting it to dm-log-writes??

Working on the scripts to allow us to do --find and then replay.

Quoted 8 lines

Since for xfs and ext4, their fsck would report false alerts just for dirty journal.

I'm adding new macro to locate next flush and replay to it, then mount it RW before we call fsck.

Or do we have options for those fscks to skip dirty journal?

Quoted 8 lines

No, you are much better off doing mount/umount before fsck. Even though e2fsck can replay a journal, it does that much slower then the kernel does.

But why do you need to teach --find to find next flush?
You could use a helper script to run every fua with --fsck --check fua. Granted, for fstests context, I agree that --find next fua may look nicer, so I have no objection to this implementation.

The point is, in my opinion fua is not the worst case we need to test. Only flush could leads us to the worst case we really need to test.

In btrfs' case, if we finished flush, but without fua, we have a super block points to all old trees, but all new trees are already written to disk.

In that flush entry, we could reach to the worst case scenario to verify all btrfs tricks are working all together to get a completely sane btrfs (even all data should be correct).

Quoted 9 lines

This should also apply to journal based filesystems (if I understand the journal thing correctly), even when all journals written but superblock not updated, we should be completely fine.
(Although for journal, we may need to reach fua entry instead of flush?)

And the other reason why we need to find next flush/fua manually is, mount will write new data, and we need to replay all the sequence until next flush/fua.

OK. but Josef addressed this in his script using dm snapshots, rather than replaying each time. I guess this is the reason the script is called replay-individual-faster.sh. You don't have to do the same, but I expect the test would run faster if you learn from experience of Josef.

Quoted 8 lines

And finally the reason about why need manually mount is, we need to workaround e2fsck/xfs_repair, so that they won't report dirty journal as error. If we have extra options to disable such behavior, I'm completely OK with current --check flush/fua --fsck method.
(BTW, for my btrfs testing, --check flush --fsck is completely good enough, to exposed possible free space cache related problems)

What I was suggesting as an alternative is --fsck ./replay-fsck-wrapper.sh where the wrapper script does the needed mount/umount and if you also use dm snapshot for the mounted volume you can continue to replay from the same point and don't need to replay from the start.

Cheers,
Amir.

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#9 lore raw
In reply to Amir Goldstein
Quoted 10 lines · Amir Goldstein
Quoted 6 lines · Qu Wenruo

This test case is originally designed to expose unexpected corruption for btrfs, where there are several reports about btrfs serious metadata corruption after power loss.

The test case itself will trigger heavy fsstress for the fs, and use dm-flakey to emulate power loss by dropping all later writes.

So you are re-posting the test with dm-flakey or converting it to dm-log-writes??

Sorry, I just noticed the date right now.

I was formatting the patch to the wrong place with old patches. Please ignore this patch.

Thanks,
Qu

Quoted 169 lines
Quoted 158 lines

For btrfs, it should be completely fine, as long as superblock write (FUA write) finishes atomically, since with metadata CoW, superblock either points to old trees or new tress, the fs should be as atomic as superblock.

For journal based filesystems, each metadata update should be journaled, so metadata operation is as atomic as journal updates.

It does show that XFS is doing the best work among the tested filesystems (Btrfs, XFS, ext4), no kernel nor xfs_repair problem at all.

For btrfs, although btrfs check doesn't report any problem, kernel reports some data checksum error, which is a little unexpected as data is CoWed by default, which should be as atomic as superblock. (Unfortunately, still not the exact problem I'm chasing for)

For EXT4, kernel is fine, but later e2fsck reports problem, which may indicates there is still something to be improved.

---
 tests/generic/479     | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/generic/479.out |   2 +
 tests/generic/group   |   1 +
 3 files changed, 112 insertions(+)
 create mode 100755 tests/generic/479
 create mode 100644 tests/generic/479.out
tests/generic/479 new file +109 -0
new file mode 100755
index 00000000..ab530231
@@ -0,0 +1,109 @@
+#! /bin/bash
+# FS QA Test 479
+#
+# Test if a filesystem can survive emulated powerloss.
+#
+# No matter what the solution a filesystem uses (journal or CoW),
+# it should survive unexpected powerloss, without major metadata
+# corruption.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2018 SuSE.  All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#-----------------------------------------------------------------------
+#
+
+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()
+{
+       ps -e | grep fsstress > /dev/null 2>&1
+       while [ $? -eq 0 ]; do
+               $KILLALL_PROG -KILL fsstress > /dev/null 2>&1
+               wait > /dev/null 2>&1
+               ps -e | grep fsstress > /dev/null 2>&1
+       done
+       _unmount_flakey &> /dev/null
+       _cleanup_flakey
+       cd /
+       rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+. ./common/dmflakey
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs generic
+_supported_os Linux
+_require_scratch
+_require_dm_target flakey
+_require_command "$KILLALL_PROG" "killall"
+
+runtime=$(($TIME_FACTOR * 15))
+loops=$(($LOAD_FACTOR * 4))
+
+for i in $(seq -w $loops); do
+       echo "=== Loop $i: $(date) ===" >> $seqres.full
+
+       _scratch_mkfs >/dev/null 2>&1
+       _init_flakey
+       _mount_flakey
+
+       ($FSSTRESS_PROG $FSSTRESS_AVOID -w -d $SCRATCH_MNT -n 1000000 \
+               -p 100 >> $seqres.full &) > /dev/null 2>&1
+
+       sleep $runtime
+
+       # Here we only want to drop all write, don't need to umount the fs
+       _load_flakey_table $FLAKEY_DROP_WRITES
+
+       ps -e | grep fsstress > /dev/null 2>&1
+       while [ $? -eq 0 ]; do
+               $KILLALL_PROG -KILL fsstress > /dev/null 2>&1
+               wait > /dev/null 2>&1
+               ps -e | grep fsstress > /dev/null 2>&1
+       done
+
+       _unmount_flakey
+       _cleanup_flakey
+
+       # Mount the fs to do proper log replay for journal based fs
+       # so later check won't report annoying dirty log and only
+       # report real problem.
+       _scratch_mount
+       _scratch_unmount
+
+       _check_scratch_fs
+done
+
+echo "Silence is golden"
+
+# success, all done
+status=0
+exit
tests/generic/479.out new file +2 -0
new file mode 100644
index 00000000..290f18b3
@@ -0,0 +1,2 @@
+QA output created by 479
+Silence is golden
tests/generic/group +0 -0
index 1e808865..5ce3db1d 100644

tests/generic/group line 484

Quoted 4 lines
tests/generic/group +1 -0
@@ -481,3 +481,4 @@
 476 auto rw
 477 auto quick exportfs
 478 auto quick
+479 auto

+ stress
--
To unsubscribe from this list: send the line "unsubscribe fstests" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html