diff options
| -rw-r--r-- | block/qcow2.c | 5 | ||||
| -rw-r--r-- | docs/system/deprecated.rst | 12 | ||||
| -rw-r--r-- | docs/tools/qemu-img.rst | 4 | ||||
| -rw-r--r-- | tests/qemu-iotests/061.out | 1 | ||||
| -rw-r--r-- | tests/qemu-iotests/082.out | 2 |
5 files changed, 24 insertions, 0 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index ea33673c55..f3fc2707cd 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -5511,6 +5511,11 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, } if (backing_file || backing_format) { + if (g_strcmp0(backing_file, s->image_backing_file) || + g_strcmp0(backing_format, s->image_backing_format)) { + warn_report("Deprecated use of amend to alter the backing file; " + "use qemu-img rebase instead"); + } ret = qcow2_change_backing_file(bs, backing_file ?: s->image_backing_file, backing_format ?: s->image_backing_format); diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst index c014e049c3..c1f019b9d2 100644 --- a/docs/system/deprecated.rst +++ b/docs/system/deprecated.rst @@ -427,6 +427,18 @@ kernel in 2018, and has also been dropped from glibc. Related binaries ---------------- +qemu-img amend to adjust backing file (since 5.1) +''''''''''''''''''''''''''''''''''''''''''''''''' + +The use of ``qemu-img amend`` to modify the name or format of a qcow2 +backing image is deprecated; this functionality was never fully +documented or tested, and interferes with other amend operations that +need access to the original backing image (such as deciding whether a +v3 zero cluster may be left unallocated when converting to a v2 +image). Rather, any changes to the backing chain should be performed +with ``qemu-img rebase -u`` either before or after the remaining +changes being performed by amend, as appropriate. + Backwards compatibility ----------------------- diff --git a/docs/tools/qemu-img.rst b/docs/tools/qemu-img.rst index e33f5575e3..c35bd64822 100644 --- a/docs/tools/qemu-img.rst +++ b/docs/tools/qemu-img.rst @@ -258,6 +258,10 @@ Command description: Amends the image format specific *OPTIONS* for the image file *FILENAME*. Not all file formats support this operation. + The set of options that can be amended are dependent on the image + format, but note that amending the backing chain relationship should + instead be performed with ``qemu-img rebase``. + --force allows some unsafe operations. Currently for -f luks, it allows to erase the last encryption key, and to overwrite an active encryption key. diff --git a/tests/qemu-iotests/061.out b/tests/qemu-iotests/061.out index b0f8befe30..44e3c624f9 100644 --- a/tests/qemu-iotests/061.out +++ b/tests/qemu-iotests/061.out @@ -370,6 +370,7 @@ wrote 131072/131072 bytes at offset 0 128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) read 131072/131072 bytes at offset 0 128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +qemu-img: warning: Deprecated use of amend to alter the backing file; use qemu-img rebase instead read 131072/131072 bytes at offset 0 128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) No errors were found on the image. diff --git a/tests/qemu-iotests/082.out b/tests/qemu-iotests/082.out index f7b3d54b28..a38a26fc57 100644 --- a/tests/qemu-iotests/082.out +++ b/tests/qemu-iotests/082.out @@ -783,10 +783,12 @@ Amend options for 'qcow2': size=<size> - Virtual disk size Testing: amend -f qcow2 -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2 +qemu-img: warning: Deprecated use of amend to alter the backing file; use qemu-img rebase instead Testing: rebase -u -b -f qcow2 TEST_DIR/t.qcow2 Testing: amend -f qcow2 -o backing_file=TEST_DIR/t.qcow2,,? TEST_DIR/t.qcow2 +qemu-img: warning: Deprecated use of amend to alter the backing file; use qemu-img rebase instead Testing: rebase -u -b -f qcow2 TEST_DIR/t.qcow2 |