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Use shorter temporary file names for kpartx

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The loopback handling in the Linux kernel limits the filenames of
files associated to loopback devices, see also linux/loop.h.
This is reflected also on userspace, as kpartx will silently do nothing
(exiting with 0) when requesting to remove a filename longer than 64
characters, as that name will obviously not match the truncated
filename. The result of this is that, when extracting qcow2 images for
the first time, if the qcow2 filename is long enough then the loopback
device will not be removed, remaining as stale in the host.

As a workaround, use a temporary file name when convering a qcow2 image
to raw, instead of using the base name of the qcow2 file.
While this still will not fix the issue when manually using a long
temporary directory (e.g. TMP_DIR=/very/long/etc...), at least should
avoid it in other cases.

Change-Id: Ibf46cd313a9d89412c0e1068fa0993be6c5a29db
This commit is contained in:
Pino Toscano 2015-04-21 10:36:33 +02:00
parent 7c4c504334
commit f35aace69f
3 changed files with 13 additions and 16 deletions
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11
elements/redhat-common/bin/extract-image
View File

@ -48,12 +48,11 @@ function extract_image() {
trap "$EACTION" EXIT
echo "Working in $WORKING"
RAW_FILE=$(basename $BASE_IMAGE_FILE)
RAW_FILE=${RAW_FILE%.qcow2}.raw
RAW_FILE=$(mktemp --tmpdir=$WORKING XXXXXX.raw)
qemu-img convert -f qcow2 -O raw $CACHED_IMAGE $WORKING/$RAW_FILE
qemu-img convert -f qcow2 -O raw $CACHED_IMAGE $RAW_FILE
ROOT_PARTITON=p$(sudo kpartx -l $WORKING/$RAW_FILE | awk "/loop[0-9]+p/"|wc -l)
ROOT_PARTITON=p$(sudo kpartx -l $RAW_FILE | awk "/loop[0-9]+p/"|wc -l)
sudo udevadm settle
# kpartx fails if no /dev/loop* exists, "losetup -f" prints first unused
@ -62,7 +61,7 @@ function extract_image() {
# XXX: Parsing stdout is dangerous, would like a better way to discover
# the device used for the image.
ROOT_LOOPDEV=$(sudo kpartx -av $WORKING/$RAW_FILE | \
ROOT_LOOPDEV=$(sudo kpartx -av $RAW_FILE | \
awk "/loop[0-9]+$ROOT_PARTITON/ {print \$3}")
# If running inside Docker, make our nodes manually, because udev will not be working.
if [ -f /.dockerenv ]; then
@ -72,7 +71,7 @@ function extract_image() {
echo "Error: Could not find /dev/mapper/$ROOT_LOOPDEV"
exit 1
fi
EACTION="sudo kpartx -d $WORKING/$RAW_FILE ; $EACTION"
EACTION="sudo kpartx -d $RAW_FILE ; $EACTION"
trap "$EACTION" EXIT
mkdir $WORKING/mnt
sudo mount /dev/mapper/$ROOT_LOOPDEV $WORKING/mnt

9
elements/rhel/root.d/10-rhel-cloud-image
View File

@ -31,13 +31,12 @@ else
WORKING=$(mktemp -d)
EACTION="rm -r $WORKING"
trap "$EACTION" EXIT
RAW_FILE=$(basename $BASE_IMAGE_FILE)
RAW_FILE=${RAW_FILE%.qcow2}.raw
qemu-img convert -f qcow2 -O raw $DIB_IMAGE_CACHE/$BASE_IMAGE_FILE $WORKING/$RAW_FILE
RAW_FILE=$(mktemp --tmpdir=$WORKING XXXXXX.raw)
qemu-img convert -f qcow2 -O raw $DIB_IMAGE_CACHE/$BASE_IMAGE_FILE $RAW_FILE
MAGIC_BIT=p1
# NOTE: On RHEL, partprobe of /dev/loop0 does not create /dev/loop0p2,
# while kpartx at least creates /dev/mapper/loop0p2.
LOOPDEV=$(sudo kpartx -av $WORKING/$RAW_FILE | awk "/loop[0-9]+$MAGIC_BIT/ {print \$3}")
LOOPDEV=$(sudo kpartx -av $RAW_FILE | awk "/loop[0-9]+$MAGIC_BIT/ {print \$3}")
# If running inside Docker, make our nodes manually, because udev will not be working.
if [ -f /.dockerenv ]; then
sudo dmsetup --noudevsync mknodes
@ -48,7 +47,7 @@ else
echo "Error: Could not find /dev/mapper/$LOOPDEV"
exit 1
fi
EACTION="sudo kpartx -d $WORKING/$RAW_FILE;$EACTION"
EACTION="sudo kpartx -d $RAW_FILE;$EACTION"
trap "$EACTION" EXIT
mkdir $WORKING/mnt
sudo mount /dev/mapper/$LOOPDEV $WORKING/mnt

9
elements/ubuntu-core/root.d/10-cache-ubuntu-image
View File

@ -52,13 +52,12 @@ else
WORKING=$(mktemp -d)
EACTION="rm -r $WORKING"
trap "$EACTION" EXIT
RAW_FILE=$(basename $BASE_IMAGE_FILE)
RAW_FILE=${RAW_FILE%.img}.raw
qemu-img convert -f qcow2 -O raw $CACHED_FILE $WORKING/$RAW_FILE
RAW_FILE=$(mktemp --tmpdir=$WORKING XXXXXX.raw)
qemu-img convert -f qcow2 -O raw $CACHED_FILE $RAW_FILE
MAGIC_BIT=p1
# NOTE: On RHEL, partprobe of /dev/loop0 does not create /dev/loop0p2,
# while kpartx at least creates /dev/mapper/loop0p2.
LOOPDEV=$(sudo kpartx -av $WORKING/$RAW_FILE | awk "/loop[0-9]+$MAGIC_BIT/ {print \$3}")
LOOPDEV=$(sudo kpartx -av $RAW_FILE | awk "/loop[0-9]+$MAGIC_BIT/ {print \$3}")
# If running inside Docker, make our nodes manually, because udev will not be working.
if [ -f /.dockerenv ]; then
sudo dmsetup --noudevsync mknodes
@ -69,7 +68,7 @@ else
echo "Error: Could not find /dev/mapper/$LOOPDEV"
exit 1
fi
EACTION="sudo kpartx -d $WORKING/$RAW_FILE;$EACTION"
EACTION="sudo kpartx -d $RAW_FILE;$EACTION"
trap "$EACTION" EXIT
mkdir $WORKING/mnt
sudo mount /dev/mapper/$LOOPDEV $WORKING/mnt