new file mode 100755
@@ -0,0 +1,149 @@
+#! /bin/bash
+# FS QA Test No. btrfs/030
+#
+# Regression test for btrfs' incremental send feature:
+#
+# 1) Create several nested directories;
+# 2) Create a read only snapshot;
+# 3) Change the parentship of some of the deepest directories in a reverse
+# way, so that parents become children and children become parents;
+# 4) Create another read only snapshot and use it for an incremental send
+# relative to the first snapshot.
+#
+# At step 4 btrfs' send entered an infinite loop, increasing the memory it
+# used while building path strings until a krealloc was unable to allocate
+# more memory, which caused a warning dump in dmesg.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2014 Filipe Manana. 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=`mktemp -d`
+status=1 # failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+ rm -fr $tmp
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# real QA test starts here
+_supported_fs btrfs
+_supported_os Linux
+_require_scratch
+_need_to_be_root
+
+FSSUM_PROG=$here/src/fssum
+[ -x $FSSUM_PROG ] || _notrun "fssum not built"
+
+rm -f $seqres.full
+
+_scratch_mkfs >/dev/null 2>&1
+_scratch_mount
+
+
+mkdir -p $SCRATCH_MNT/a/b/c
+echo "hello" > $SCRATCH_MNT/a/b/c/file.txt
+mkdir $SCRATCH_MNT/a/b/c/d
+mkdir $SCRATCH_MNT/a/b/c2
+mkdir $SCRATCH_MNT/a/b/www
+echo "hey" > $SCRATCH_MNT/a/b/foobar.txt
+mkdir -p $SCRATCH_MNT/a/b/c3/x/y
+
+# Directory tree looks like:
+#
+# . (ino 256)
+# |-- a/ (ino 257)
+# |-- b/ (ino 258)
+# |-- c/ (ino 259)
+# | |-- file.txt (ino 260)
+# | |-- d/ (ino 261)
+# |
+# |-- c2/ (ino 262)
+# |-- www/ (ino 263)
+# |-- foobar.txt (ino 264)
+# |
+# |-- c3/ (ino 265)
+# |-- x/ (ino 266)
+# |-- y/ (ino 267)
+
+run_check $BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT \
+ $SCRATCH_MNT/mysnap1
+
+echo " world" >> $SCRATCH_MNT/a/b/c/file.txt
+mv $SCRATCH_MNT/a/b/c/d $SCRATCH_MNT/a/b/c2/d2
+mv $SCRATCH_MNT/a/b/c $SCRATCH_MNT/a/b/c2/d2/cc
+mv $SCRATCH_MNT/a/b/c3/x/y $SCRATCH_MNT/a/b/c2/y2
+mv $SCRATCH_MNT/a/b/c3/x $SCRATCH_MNT/a/b/c2/y2/x2
+mv $SCRATCH_MNT/a/b/c3 $SCRATCH_MNT/a/b/c2/y2/x2/Z
+mv $SCRATCH_MNT/a/b/www $SCRATCH_MNT/a/b/c2/y2/x2/WWW
+mv $SCRATCH_MNT/a/b/foobar.txt $SCRATCH_MNT/a/b/c2/y2/x2/qwerty.txt
+ln $SCRATCH_MNT/a/b/c2/d2/cc/file.txt $SCRATCH_MNT/a/b/c2/y2/x2/Z/file_link.txt
+mv $SCRATCH_MNT/a/b/c2/d2/cc/file.txt $SCRATCH_MNT/a/b/c2/y2/x2
+
+# Directory tree now looks like:
+#
+# . (ino 256)
+# |-- a/ (ino 257)
+# |-- b/ (ino 258)
+# |-- c2/ (ino 262)
+# |-- d2/ (ino 261)
+# | |-- cc/ (ino 259)
+# | |-- file.txt (ino 260)
+# |-- y2/ (ino 267)
+# |-- x2/ (ino 266)
+# |-- qwerty.txt (ino 264)
+# |-- WWW/ (ino 263)
+# |-- Z/ (ino 265)
+# |-- file_link.txt
+
+run_check $BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT \
+ $SCRATCH_MNT/mysnap2
+
+run_check $FSSUM_PROG -A -f -w $tmp/1.fssum $SCRATCH_MNT/mysnap1
+run_check $FSSUM_PROG -A -f -w $tmp/2.fssum -x $SCRATCH_MNT/mysnap2/mysnap1 \
+ $SCRATCH_MNT/mysnap2
+
+run_check $BTRFS_UTIL_PROG send $SCRATCH_MNT/mysnap1 -f $tmp/1.snap
+run_check $BTRFS_UTIL_PROG send -p $SCRATCH_MNT/mysnap1 $SCRATCH_MNT/mysnap2 \
+ -f $tmp/2.snap
+
+_scratch_unmount
+_check_btrfs_filesystem $SCRATCH_DEV
+_scratch_mkfs >/dev/null 2>&1
+_scratch_mount
+
+run_check $BTRFS_UTIL_PROG receive $SCRATCH_MNT -f $tmp/1.snap
+run_check $FSSUM_PROG -r $tmp/1.fssum $SCRATCH_MNT/mysnap1 2>> $seqres.full
+
+run_check $BTRFS_UTIL_PROG receive $SCRATCH_MNT -f $tmp/2.snap
+run_check $FSSUM_PROG -r $tmp/2.fssum $SCRATCH_MNT/mysnap2 2>> $seqres.full
+
+_scratch_unmount
+_check_btrfs_filesystem $SCRATCH_DEV
+
+status=0
+exit
new file mode 100644
@@ -0,0 +1 @@
+QA output created by 030
@@ -32,3 +32,4 @@
027 auto quick
028 auto quick
029 auto quick
+030 auto quick
Regression test for btrfs' incremental send feature: 1) Create several nested directories; 2) Create a read only snapshot; 3) Change the parentship of some of the deepest directories in a reverse way, so that parents become children and children become parents; 4) Create another read only snapshot and use it for an incremental send relative to the first snapshot. At step 4 btrfs' send entered an infinite loop, increasing the memory it used while building path strings until a krealloc was unable to allocate more memory, which caused a warning dump in dmesg. The following linux kernel patch fixes this issue. Btrfs: fix infinite path build loops in incremental send (https://patchwork.kernel.org/patch/3522361/) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> --- V2: Updated test to trigger one more code path in the corresponding btrfs linux kernel patch that fixes this issue. V3: Addressed Josef's comments, make the test not depend on 'btrfs send' and fssum output, as it changed often in the past and can change again. tests/btrfs/030 | 149 +++++++++++++++++++++++++++++++++++++++++++++++++++ tests/btrfs/030.out | 1 + tests/btrfs/group | 1 + 3 files changed, 151 insertions(+) create mode 100755 tests/btrfs/030 create mode 100644 tests/btrfs/030.out