On Wed, Jun 17, 2015 at 12:44:55PM +0100, fdman...@kernel.org wrote:
> Currently there is not way for a user to know what is the minimum size a
> device of a btrfs filesystem can be resized to. Sometimes the value of
> total allocated space (sum of all allocated chunks/device extents), which
> can be parsed from 'btrfs filesystem show' and 'btrfs filesystem usage',
> works as the minimum size, but sometimes it does not, namely when device
> extents have to relocated to holes (unallocated space) within the new
> size of the device (the total allocated space sum).
>
> This change adds the ability to reliably compute such minimum value and
> extents 'btrfs filesystem resize' with the following syntax to get such
> value:
The test fails after I do this before unmount:
$SUDO_HELPER $TOP/btrfs balance start -mconvert=single -sconvert=single -f
$TEST_MNT
shrink_test
Output:
############### root_helper ../btrfs filesystem resize get_min_size ../tests/mnt
6480199680 bytes (6.04GiB)
min size = 6480199680
############### root_helper ../btrfs filesystem resize 6480199680 ../tests/mnt
ERROR: unable to resize '../tests/mnt' - No space left on device
Resize '../tests/mnt' of '6480199680'
Last successful resize before this was:
Resize '../tests/mnt' of '7553941504'
> btrfs filesystem resize [devid:]get_min_size
I don't think this is the right interface, IMHO this fits into the
inspect-internal group. The syntax for 'fi resize' is a bit cumbersome, I'd
like to avoid complicating it further. But you can keep it as-is until the the
bugs are fixed.
> --- a/Makefile.in
> +++ b/Makefile.in
> @@ -46,7 +46,7 @@ libbtrfs_objects = send-stream.o send-utils.o rbtree.o
> btrfs-list.o crc32c.o \
> libbtrfs_headers = send-stream.h send-utils.h send.h rbtree.h btrfs-list.h \
> crc32c.h list.h kerncompat.h radix-tree.h extent-cache.h \
> extent_io.h ioctl.h ctree.h btrfsck.h version.h
> -TESTS = fsck-tests.sh convert-tests.sh
> +TESTS = fsck-tests.sh convert-tests.sh shrink-min-size-tests.sh
>
> prefix ?= @prefix@
> exec_prefix = @exec_prefix@
> @@ -161,6 +161,10 @@ $(BUILDDIRS):
> @echo "Making all in $(patsubst build-%,%,$@)"
> $(Q)$(MAKE) $(MAKEOPTS) -C $(patsubst build-%,%,$@)
>
> +test-shrink-min-size: btrfs mkfs.btrfs
> + @echo " [TEST] shrink-min-size-tests.sh"
> + $(Q)bash tests/shrink-min-size-tests.sh
Please move the test under the test-misc, for now it's a catch-all category.
General comments to the test script(s):
* the tests are supposed to be run unprivileged as much as possible, so the
SUDO_HELPER needs to be used explicitly
* use the git binaries everywhere
(diff below)
> +shrink_test()
> +{
> + min_size=$(btrfs filesystem resize get_min_size $TEST_MNT)
sudo helper, use binary from git
> + if [ $? != 0 ]; then
> + _fail "Failed to get minimum size"
> + fi
> + min_size=$(echo $min_size | cut -d ' ' -f 1)
> + echo "min size = ${min_size}" >> $RESULTS
> + run_check btrfs filesystem resize $min_size $TEST_MNT
sudo helper, use binary from git
> +}
> +
> +run_check truncate -s 20G $IMAGE
> +run_check $SUDO_HELPER $TOP/mkfs.btrfs -f $IMAGE
sudo helper not necessary, it's a file-backed image
> +run_check $SUDO_HELPER mount $IMAGE $TEST_MNT
> +
> +# Create 7 data block groups, each with a size of 1Gb.
> +for ((i = 1; i <= 7; i++)); do
> + run_check fallocate -l 1G $TEST_MNT/foo$i
This failed as the mountpoint is created by root and I'm running the
test under my user. A chown after mount fixed it.
> +done
[...]
@@ -23,19 +23,23 @@ setup_root_helper
shrink_test()
{
- min_size=$(btrfs filesystem resize get_min_size $TEST_MNT)
+ min_size=$(run_check_stdout $SUDO_HELPER $TOP/btrfs filesystem resize
get_min_size $TEST_MNT)
if [ $? != 0 ]; then
_fail "Failed to get minimum size"
fi
min_size=$(echo $min_size | cut -d ' ' -f 1)
echo "min size = ${min_size}" >> $RESULTS
- run_check btrfs filesystem resize $min_size $TEST_MNT
+ run_check $SUDO_HELPER $TOP/btrfs filesystem resize $min_size $TEST_MNT
}
run_check truncate -s 20G $IMAGE
-run_check $SUDO_HELPER $TOP/mkfs.btrfs -f $IMAGE
+run_check $TOP/mkfs.btrfs -f $IMAGE
run_check $SUDO_HELPER mount $IMAGE $TEST_MNT
+user=$(id -un)
+group=$(id -gn)
+run_check $SUDO_HELPER chown $user:$group $TEST_MNT
+
# Create 7 data block groups, each with a size of 1Gb.
for ((i = 1; i <= 7; i++)); do
run_check fallocate -l 1G $TEST_MNT/foo$i
@@ -43,7 +47,7 @@ done
# Make sure they are persisted (all the chunk, device and block group items
# added to the chunk/dev/extent trees).
-run_check btrfs filesystem sync $TEST_MNT
+run_check $TOP/btrfs filesystem sync $TEST_MNT
# Now remove 3 of those 1G files. This will result in 3 block groups becoming
# unused, which will be automatically deleted by the cleaner kthread, and this
@@ -58,9 +62,9 @@ run_check rm -f $TEST_MNT/foo6
# groups - it could have been sleeping when they become unused. Then wait a bit
# to allow the cleaner kthread to delete them and then finally ensure the
# transaction started by the cleaner kthread is committed.
-run_check btrfs filesystem sync $TEST_MNT
+run_check $TOP/btrfs filesystem sync $TEST_MNT
sleep 3
-run_check btrfs filesystem sync $TEST_MNT
+run_check $TOP/btrfs filesystem sync $TEST_MNT
# Now attempt to get the minimum size we can resize the filesystem to and
verify
# the resize operation succeeds. This size closely matches the sum of the size
---
--
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