* [PATCH 1/4] resize2fs: fix off-line resize of file systems with flex_bg && !resize_inode
2013-04-01 0:43 ` [PATCH 0/4] e2fsprogs: fix off-line resizing of small ext4 file systems Theodore Ts'o
@ 2013-04-01 0:44 ` Theodore Ts'o
2013-04-01 0:44 ` [PATCH 2/4] mke2fs: don't display bigalloc/quota fs feature warnings in quiet mode Theodore Ts'o
` (2 subsequent siblings)
3 siblings, 0 replies; 8+ messages in thread
From: Theodore Ts'o @ 2013-04-01 0:44 UTC (permalink / raw)
To: Ext4 Developers List; +Cc: john.jolly, Theodore Ts'o
When doing an off-line resize2fs of an initially very small file
system, it's possible to run out of reserved gdt blocks (which are
reserved via the resize inode). Once we run out, we need to move the
allocation bitmaps and inode table out of the way to grow the gdt
blocks. Unfortunately, when moving these metadata blocks, it was
possible that a block that had been just been newly allocated for a
new block group could also get allocated for a metadata block for an
existing block group that was being moved.
To prevent this, after we grow the gdt blocks and allocate the
metadata blocks for the new block groups, make sure all of these
blocks are marked as reserved.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: John Jolly <john.jolly@gmail.com>
---
resize/resize2fs.c | 58 ++++++++++++++++++++++++++++++++++++++++++------------
1 file changed, 45 insertions(+), 13 deletions(-)
diff --git a/resize/resize2fs.c b/resize/resize2fs.c
index c9458ea..7c4f86a 100644
--- a/resize/resize2fs.c
+++ b/resize/resize2fs.c
@@ -51,6 +51,8 @@ static errcode_t move_itables(ext2_resize_t rfs);
static errcode_t fix_resize_inode(ext2_filsys fs);
static errcode_t ext2fs_calculate_summary_stats(ext2_filsys fs);
static errcode_t fix_sb_journal_backup(ext2_filsys fs);
+static errcode_t mark_table_blocks(ext2_filsys fs,
+ ext2fs_block_bitmap bmap);
/*
* Some helper CPP macros
@@ -306,9 +308,6 @@ static void free_gdp_blocks(ext2_filsys fs,
/*
* This routine is shared by the online and offline resize routines.
* All of the information which is adjusted in memory is done here.
- *
- * The reserve_blocks parameter is only needed when shrinking the
- * filesystem.
*/
errcode_t adjust_fs_info(ext2_filsys fs, ext2_filsys old_fs,
ext2fs_block_bitmap reserve_blocks, blk64_t new_size)
@@ -407,12 +406,21 @@ retry:
real_end = (((blk64_t) EXT2_BLOCKS_PER_GROUP(fs->super) *
fs->group_desc_count)) - 1 +
fs->super->s_first_data_block;
- retval = ext2fs_resize_block_bitmap2(ext2fs_blocks_count(fs->super)-1,
- real_end, fs->block_map);
-
+ retval = ext2fs_resize_block_bitmap2(new_size - 1,
+ real_end, fs->block_map);
if (retval) goto errout;
/*
+ * If we are growing the file system, also grow the size of
+ * the reserve_blocks bitmap
+ */
+ if (reserve_blocks && new_size > ext2fs_blocks_count(old_fs->super)) {
+ retval = ext2fs_resize_block_bitmap2(new_size - 1,
+ real_end, reserve_blocks);
+ if (retval) goto errout;
+ }
+
+ /*
* Reallocate the group descriptors as necessary.
*/
if (old_fs->desc_blocks != fs->desc_blocks) {
@@ -512,6 +520,15 @@ retry:
else
old_desc_blocks = fs->desc_blocks +
fs->super->s_reserved_gdt_blocks;
+
+ /*
+ * If we changed the number of block_group descriptor blocks,
+ * we need to make sure they are all marked as reserved in the
+ * file systems's block allocation map.
+ */
+ for (i = 0; i < old_fs->group_desc_count; i++)
+ ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
+
for (i = old_fs->group_desc_count;
i < fs->group_desc_count; i++) {
memset(ext2fs_group_desc(fs, fs->group_desc, i), 0,
@@ -578,6 +595,17 @@ retry:
}
retval = 0;
+ /*
+ * Mark all of the metadata blocks as reserved so they won't
+ * get allocated by the call to ext2fs_allocate_group_table()
+ * in blocks_to_move(), where we allocate new blocks to
+ * replace those allocation bitmap and inode table blocks
+ * which have to get relocated to make space for an increased
+ * number of the block group descriptors.
+ */
+ if (reserve_blocks)
+ mark_table_blocks(fs, reserve_blocks);
+
errout:
return (retval);
}
@@ -716,6 +744,7 @@ static errcode_t mark_table_blocks(ext2_filsys fs,
ext2fs_block_bitmap bmap)
{
dgrp_t i;
+ blk64_t blk;
for (i = 0; i < fs->group_desc_count; i++) {
ext2fs_reserve_super_and_bgd(fs, i, bmap);
@@ -723,21 +752,24 @@ static errcode_t mark_table_blocks(ext2_filsys fs,
/*
* Mark the blocks used for the inode table
*/
- ext2fs_mark_block_bitmap_range2(bmap,
- ext2fs_inode_table_loc(fs, i),
- fs->inode_blocks_per_group);
+ blk = ext2fs_inode_table_loc(fs, i);
+ if (blk)
+ ext2fs_mark_block_bitmap_range2(bmap, blk,
+ fs->inode_blocks_per_group);
/*
* Mark block used for the block bitmap
*/
- ext2fs_mark_block_bitmap2(bmap,
- ext2fs_block_bitmap_loc(fs, i));
+ blk = ext2fs_block_bitmap_loc(fs, i);
+ if (blk)
+ ext2fs_mark_block_bitmap2(bmap, blk);
/*
* Mark block used for the inode bitmap
*/
- ext2fs_mark_block_bitmap2(bmap,
- ext2fs_inode_bitmap_loc(fs, i));
+ blk = ext2fs_inode_bitmap_loc(fs, i);
+ if (blk)
+ ext2fs_mark_block_bitmap2(bmap, blk);
}
return 0;
}
--
1.7.12.rc0.22.gcdd159b
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 3/4] tests: create crcsum progam to support resizing tests
2013-04-01 0:43 ` [PATCH 0/4] e2fsprogs: fix off-line resizing of small ext4 file systems Theodore Ts'o
2013-04-01 0:44 ` [PATCH 1/4] resize2fs: fix off-line resize of file systems with flex_bg && !resize_inode Theodore Ts'o
2013-04-01 0:44 ` [PATCH 2/4] mke2fs: don't display bigalloc/quota fs feature warnings in quiet mode Theodore Ts'o
@ 2013-04-01 0:44 ` Theodore Ts'o
2013-04-01 0:44 ` [PATCH 4/4] tests: add more tests for off-line resizing Theodore Ts'o
3 siblings, 0 replies; 8+ messages in thread
From: Theodore Ts'o @ 2013-04-01 0:44 UTC (permalink / raw)
To: Ext4 Developers List; +Cc: john.jolly, Theodore Ts'o
The only checksum program which we can reliably count upon being
installed on all systems is "sum", which is not a particular robust
checksum. The problem with using md5sum or sha1sum is it hat it may
not be installed on all systems. So create a crcsum program which is
used so we can validate that a data file on a resized file system has
not been corrupted.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
tests/progs/Makefile.in | 6 ++++-
tests/progs/crcsum.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++
tests/test_config | 1 +
3 files changed, 76 insertions(+), 1 deletion(-)
create mode 100644 tests/progs/crcsum.c
diff --git a/tests/progs/Makefile.in b/tests/progs/Makefile.in
index 0e28192..e3c1ef4 100644
--- a/tests/progs/Makefile.in
+++ b/tests/progs/Makefile.in
@@ -13,7 +13,7 @@ INSTALL = @INSTALL@
MK_CMDS= _SS_DIR_OVERRIDE=../../lib/ss ../../lib/ss/mk_cmds
-PROGS= test_icount
+PROGS= test_icount crcsum
TEST_REL_OBJS= test_rel.o test_rel_cmds.o
@@ -34,6 +34,10 @@ test_rel: $(TEST_REL_OBJS) $(DEPLIBS)
$(E) " LD $@"
$(Q) $(LD) $(ALL_LDFLAGS) -o test_rel $(TEST_REL_OBJS) $(LIBS)
+crcsum: crcsum.o $(DEPLIBS)
+ $(E) " LD $@"
+ $(Q) $(LD) $(ALL_LDFLAGS) -o crcsum crcsum.o $(LIBS)
+
test_rel_cmds.c: test_rel_cmds.ct
$(E) " MK_CMDS $@"
$(Q) $(MK_CMDS) $(srcdir)/test_rel_cmds.ct
diff --git a/tests/progs/crcsum.c b/tests/progs/crcsum.c
new file mode 100644
index 0000000..bee979b
--- /dev/null
+++ b/tests/progs/crcsum.c
@@ -0,0 +1,70 @@
+/*
+ * crcsum.c
+ *
+ * Copyright (C) 2013 Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#include "config.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#ifdef HAVE_GETOPT_H
+#include <getopt.h>
+#endif
+#include <fcntl.h>
+
+#include "et/com_err.h"
+#include "ss/ss.h"
+#include "ext2fs/ext2fs.h"
+
+
+int main(int argc, char **argv)
+{
+ int c;
+ uint32_t crc = ~0;
+ uint32_t (*csum_func)(uint32_t crc, unsigned char const *p,
+ size_t len);
+ FILE *f;
+
+ csum_func = ext2fs_crc32c_le;
+
+ while ((c = getopt (argc, argv, "B")) != EOF) {
+ switch (c) {
+ case 'B':
+ csum_func = ext2fs_crc32c_be;
+ break;
+ default:
+ com_err(argv[0], 0, "Usage: crcsum [-b] [file]\n");
+ return 1;
+ }
+ }
+
+ if (optind == argc)
+ f = stdin;
+ else {
+ f = fopen(argv[optind], "r");
+ if (!f) {
+ com_err(argv[0], errno, "while trying to open %s\n",
+ argv[optind]);
+ exit(1);
+ }
+ }
+
+ while (!feof(f)) {
+ unsigned char buf[4096];
+
+ int c = fread(buf, 1, sizeof(buf), f);
+
+ if (c)
+ crc = csum_func(crc, buf, c);
+ }
+ printf("%u\n", crc);
+ return 0;
+}
diff --git a/tests/test_config b/tests/test_config
index 0ba8b5e..36b53b7 100644
--- a/tests/test_config
+++ b/tests/test_config
@@ -19,6 +19,7 @@ RESIZE2FS="$USE_VALGRIND $RESIZE2FS_EXE"
E2UNDO_EXE="../misc/e2undo"
TEST_REL=../tests/progs/test_rel
TEST_ICOUNT=../tests/progs/test_icount
+CRCSUM=../tests/progs/crcsum
LD_LIBRARY_PATH=../lib:../lib/ext2fs:../lib/e2p:../lib/et:../lib/ss
DYLD_LIBRARY_PATH=../lib:../lib/ext2fs:../lib/e2p:../lib/et:../lib/ss
export LD_LIBRARY_PATH
--
1.7.12.rc0.22.gcdd159b
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 4/4] tests: add more tests for off-line resizing
2013-04-01 0:43 ` [PATCH 0/4] e2fsprogs: fix off-line resizing of small ext4 file systems Theodore Ts'o
` (2 preceding siblings ...)
2013-04-01 0:44 ` [PATCH 3/4] tests: create crcsum progam to support resizing tests Theodore Ts'o
@ 2013-04-01 0:44 ` Theodore Ts'o
3 siblings, 0 replies; 8+ messages in thread
From: Theodore Ts'o @ 2013-04-01 0:44 UTC (permalink / raw)
To: Ext4 Developers List; +Cc: john.jolly, Theodore Ts'o
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
tests/r_1024_small_bg/script | 27 +++++++
tests/r_64bit_big_expand/script | 27 +++++++
tests/r_bigalloc_big_expand/script | 27 +++++++
tests/r_ext4_big_expand/script | 27 +++++++
tests/r_ext4_small_bg/script | 27 +++++++
tests/scripts/resize_test | 139 +++++++++++++++++++++++++++++++++++++
6 files changed, 274 insertions(+)
create mode 100644 tests/r_1024_small_bg/script
create mode 100644 tests/r_64bit_big_expand/script
create mode 100644 tests/r_bigalloc_big_expand/script
create mode 100644 tests/r_ext4_big_expand/script
create mode 100644 tests/r_ext4_small_bg/script
create mode 100755 tests/scripts/resize_test
diff --git a/tests/r_1024_small_bg/script b/tests/r_1024_small_bg/script
new file mode 100644
index 0000000..fafcf91
--- /dev/null
+++ b/tests/r_1024_small_bg/script
@@ -0,0 +1,27 @@
+if test -x $RESIZE2FS_EXE -a -x $DEBUGFS_EXE; then
+
+test_description="ext2 1024 blocksize with small block groups"
+FEATURES="-t ext2 -O ^resize_inode -b 1024 -g 1024"
+SIZE_1=64M
+SIZE_2=2G
+LOG=$test_name.log
+E2FSCK=../e2fsck/e2fsck
+
+
+. $cmd_dir/scripts/resize_test
+
+if resize_test
+then
+ echo "$test_name: $test_description: ok"
+ touch $test_name.ok
+else
+ echo "$test_name: $test_description: failed"
+ touch $test_name.failed
+fi
+
+unset FEATURES SIZE_1 SIZE_2 LOG E2FSCK
+
+else #if test -x $RESIZE2FS_EXE -a -x $DEBUGFS_EXE; then
+ echo "$test_name: $test_description: skipped"
+fi
+
diff --git a/tests/r_64bit_big_expand/script b/tests/r_64bit_big_expand/script
new file mode 100644
index 0000000..3b34a62
--- /dev/null
+++ b/tests/r_64bit_big_expand/script
@@ -0,0 +1,27 @@
+if test -x $RESIZE2FS_EXE -a -x $DEBUGFS_EXE; then
+
+test_description="very large fs growth using ext4 w/64bit"
+FEATURES="-t ext4 -O 64bit"
+SIZE_1=512M
+SIZE_2=2T
+LOG=$test_name.log
+E2FSCK=../e2fsck/e2fsck
+
+
+. $cmd_dir/scripts/resize_test
+
+if resize_test
+then
+ echo "$test_name: $test_description: ok"
+ touch $test_name.ok
+else
+ echo "$test_name: $test_description: failed"
+ touch $test_name.failed
+fi
+
+unset FEATURES SIZE_1 SIZE_2 LOG E2FSCK
+
+else #if test -x $RESIZE2FS_EXE -a -x $DEBUGFS_EXE; then
+ echo "$test_name: $test_description: skipped"
+fi
+
diff --git a/tests/r_bigalloc_big_expand/script b/tests/r_bigalloc_big_expand/script
new file mode 100644
index 0000000..2b9cc63
--- /dev/null
+++ b/tests/r_bigalloc_big_expand/script
@@ -0,0 +1,27 @@
+if test -x $RESIZE2FS_EXE -a -x $DEBUGFS_EXE; then
+
+test_description="ext4 with bigalloc"
+FEATURES="-t ext4 -O bigalloc"
+SIZE_1=512M
+SIZE_2=2T
+LOG=$test_name.log
+E2FSCK=../e2fsck/e2fsck
+RESIZE2FS_OPTS=-f
+
+. $cmd_dir/scripts/resize_test
+
+if resize_test
+then
+ echo "$test_name: $test_description: ok"
+ touch $test_name.ok
+else
+ echo "$test_name: $test_description: failed"
+ touch $test_name.failed
+fi
+
+unset FEATURES SIZE_1 SIZE_2 LOG E2FSCK
+
+else #if test -x $RESIZE2FS_EXE -a -x $DEBUGFS_EXE; then
+ echo "$test_name: $test_description: skipped"
+fi
+
diff --git a/tests/r_ext4_big_expand/script b/tests/r_ext4_big_expand/script
new file mode 100644
index 0000000..fb31d7a
--- /dev/null
+++ b/tests/r_ext4_big_expand/script
@@ -0,0 +1,27 @@
+if test -x $RESIZE2FS_EXE -a -x $DEBUGFS_EXE; then
+
+test_description="very large fs growth using ext4"
+FEATURES="-t ext4"
+SIZE_1=512M
+SIZE_2=2T
+LOG=$test_name.log
+E2FSCK=../e2fsck/e2fsck
+
+
+. $cmd_dir/scripts/resize_test
+
+if resize_test
+then
+ echo "$test_name: $test_description: ok"
+ touch $test_name.ok
+else
+ echo "$test_name: $test_description: failed"
+ touch $test_name.failed
+fi
+
+unset FEATURES SIZE_1 SIZE_2 LOG E2FSCK
+
+else #if test -x $RESIZE2FS_EXE -a -x $DEBUGFS_EXE; then
+ echo "$test_name: $test_description: skipped"
+fi
+
diff --git a/tests/r_ext4_small_bg/script b/tests/r_ext4_small_bg/script
new file mode 100644
index 0000000..553cbd8
--- /dev/null
+++ b/tests/r_ext4_small_bg/script
@@ -0,0 +1,27 @@
+if test -x $RESIZE2FS_EXE -a -x $DEBUGFS_EXE; then
+
+test_description="ext4 1024 blocksize with small block groups"
+FEATURES="-t ext4 -O ^resize_inode -b 1024 -g 512"
+SIZE_1=64M
+SIZE_2=2G
+LOG=$test_name.log
+E2FSCK=../e2fsck/e2fsck
+
+
+. $cmd_dir/scripts/resize_test
+
+if resize_test
+then
+ echo "$test_name: $test_description: ok"
+ touch $test_name.ok
+else
+ echo "$test_name: $test_description: failed"
+ touch $test_name.failed
+fi
+
+unset FEATURES SIZE_1 SIZE_2 LOG E2FSCK
+
+else #if test -x $RESIZE2FS_EXE -a -x $DEBUGFS_EXE; then
+ echo "$test_name: $test_description: skipped"
+fi
+
diff --git a/tests/scripts/resize_test b/tests/scripts/resize_test
new file mode 100755
index 0000000..964150e
--- /dev/null
+++ b/tests/scripts/resize_test
@@ -0,0 +1,139 @@
+#!/bin/sh
+
+resize_test () {
+
+rm -f $TMPFILE
+touch $TMPFILE
+echo $MKE2FS $FEATURES -qF $TMPFILE $SIZE_1 > $LOG
+$MKE2FS $FEATURES -qF $TMPFILE $SIZE_1 >> $LOG
+
+OUT_TMP=$(mktemp -t csum-tmp.XXXXXX)
+
+date > $OUT_TMP
+cat $E2FSCK >> $OUT_TMP
+echo $CRCSUM $OUT_TMP >> $LOG 2>&1
+CSUM_1=$($CRCSUM $OUT_TMP)
+echo Checksum is $CSUM_1 >> $LOG
+
+echo Setting up file system >> $LOG
+$DEBUGFS -w $TMPFILE >> $LOG 2>&1 << EOF
+mkdir test
+cd test
+write $OUT_TMP e2fsck
+ls /test
+stat /test/e2fsck
+quit
+EOF
+echo " " >> $LOG
+
+rm -f $OUT_TMP
+
+echo $FSCK -fy $TMPFILE >> $LOG 2>&1
+$FSCK -fy $TMPFILE >> $LOG 2>&1
+
+echo $RESIZE2FS $RESIZE2FS_OPTS -d 31 $TMPFILE $SIZE_2 >> $LOG 2>&1
+if ! $RESIZE2FS $RESIZE2FS_OPTS -d 31 $TMPFILE $SIZE_2 >> $LOG 2>&1
+then
+ return 1
+fi
+
+echo $FSCK -fp $TMPFILE >> $LOG 2>&1
+if ! $FSCK -fp $TMPFILE >> $LOG 2>&1
+then
+ dumpe2fs $TMPFILE >> $LOG
+ return 1
+fi
+
+echo $DEBUGFS -R "dump /test/e2fsck $OUT_TMP" $TMPFILE >> $LOG 2>&1
+$DEBUGFS -R "dump /test/e2fsck $OUT_TMP" $TMPFILE >> $LOG 2>&1
+
+echo $CRCSUM $OUT_TMP >> $LOG 2>&1
+CSUM_2=$($CRCSUM $OUT_TMP)
+echo Checksum is $CSUM_2 >> $LOG
+
+if test "$CSUM_1" != "$CSUM_2"
+then
+ return 1
+fi
+
+echo $RESIZE2FS $RESIZE2FS_OPTS -d 31 -M $TMPFILE $SIZE_2 >> $LOG 2>&1
+if ! $RESIZE2FS $RESIZE2FS_OPTS -d 31 -M $TMPFILE $SIZE_2 >> $LOG 2>&1
+then
+ return 1
+fi
+
+echo $FSCK -fp $TMPFILE >> $LOG 2>&1
+if ! $FSCK -fp $TMPFILE >> $LOG 2>&1
+then
+ dumpe2fs $TMPFILE >> $LOG
+ return 1
+fi
+
+echo $DEBUGFS -R "dump /test/e2fsck $OUT_TMP" $TMPFILE >> $LOG 2>&1
+$DEBUGFS -R "dump /test/e2fsck $OUT_TMP" $TMPFILE >> $LOG 2>&1
+
+echo $CRCSUM $OUT_TMP >> $LOG 2>&1
+CSUM_2=$($CRCSUM $OUT_TMP)
+echo Checksum is $CSUM_2 >> $LOG
+
+if test "$CSUM_1" != "$CSUM_2"
+then
+ return 1
+fi
+
+echo $RESIZE2FS $RESIZE2FS_OPTS -d 31 -M $TMPFILE $SIZE_2 >> $LOG 2>&1
+if ! $RESIZE2FS $RESIZE2FS_OPTS -d 31 -M $TMPFILE $SIZE_2 >> $LOG 2>&1
+then
+ return 1
+fi
+
+echo $FSCK -fp $TMPFILE >> $LOG 2>&1
+if ! $FSCK -fp $TMPFILE >> $LOG 2>&1
+then
+ dumpe2fs $TMPFILE >> $LOG
+ return 1
+fi
+
+echo $DEBUGFS -R "dump /test/e2fsck $OUT_TMP" $TMPFILE >> $LOG 2>&1
+$DEBUGFS -R "dump /test/e2fsck $OUT_TMP" $TMPFILE >> $LOG 2>&1
+
+echo $CRCSUM $OUT_TMP >> $LOG 2>&1
+CSUM_2=$($CRCSUM $OUT_TMP)
+echo Checksum is $CSUM_2 >> $LOG
+
+if test "$CSUM_1" != "$CSUM_2"
+then
+ return 1
+fi
+
+echo $RESIZE2FS $RESIZE2FS_OPTS -d 31 -M $TMPFILE $SIZE_2 >> $LOG 2>&1
+if ! $RESIZE2FS $RESIZE2FS_OPTS -d 31 -M $TMPFILE $SIZE_2 >> $LOG 2>&1
+then
+ return 1
+fi
+
+echo $FSCK -fp $TMPFILE >> $LOG 2>&1
+if ! $FSCK -fp $TMPFILE >> $LOG 2>&1
+then
+ dumpe2fs $TMPFILE >> $LOG
+ return 1
+fi
+
+echo $DEBUGFS -R "dump /test/e2fsck $OUT_TMP" $TMPFILE >> $LOG 2>&1
+$DEBUGFS -R "dump /test/e2fsck $OUT_TMP" $TMPFILE >> $LOG 2>&1
+
+echo $CRCSUM $OUT_TMP >> $LOG 2>&1
+CSUM_2=$($CRCSUM $OUT_TMP)
+echo Checksum is $CSUM_2 >> $LOG
+
+rm $OUT_TMP
+unset OUT_TMP
+
+if test "$CSUM_1" != "$CSUM_2"
+then
+ return 1
+fi
+
+return 0
+
+}
--
1.7.12.rc0.22.gcdd159b
^ permalink raw reply related [flat|nested] 8+ messages in thread