QEMU 2.11 introduced the --shrink option for qemu-img resize to avoid
accidentally shrinking images (commit 4ffca8904a3). However, for
compatibility reasons, it was not enforced for raw images yet, but only
a deprecation warning was printed. This warning has existed for long
enough that we can now finally require --shrink for raw images, too, and
error out if it's not given.
Documentation already describes the state as it is after this patch.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
qemu-img.c | 17 +++--------------
1 file changed, 3 insertions(+), 14 deletions(-)
diff --git a/qemu-img.c b/qemu-img.c
index e3b2ec3e78..f6a2703039 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -4011,20 +4011,9 @@ static int img_resize(int argc, char **argv)
}
if (total_size < current_size && !shrink) {
- warn_report("Shrinking an image will delete all data beyond the "
- "shrunken image's end. Before performing such an "
- "operation, make sure there is no important data there.");
-
- if (g_strcmp0(bdrv_get_format_name(blk_bs(blk)), "raw") != 0) {
- error_report(
- "Use the --shrink option to perform a shrink operation.");
- ret = -1;
- goto out;
- } else {
- warn_report("Using the --shrink option will suppress this message. "
- "Note that future versions of qemu-img may refuse to "
- "shrink images without this option.");
- }
+ error_report("Use the --shrink option to perform a shrink operation.");
+ ret = -1;
+ goto out;
}
/*
--
2.25.4
On Fri, Jul 10, 2020 at 02:17:17PM +0200, Kevin Wolf wrote: > QEMU 2.11 introduced the --shrink option for qemu-img resize to avoid > accidentally shrinking images (commit 4ffca8904a3). However, for > compatibility reasons, it was not enforced for raw images yet, but only > a deprecation warning was printed. This warning has existed for long > enough that we can now finally require --shrink for raw images, too, and > error out if it's not given. Libvirt has used the --shrink flag since Aug 2018, so this is safe from our POV. > Documentation already describes the state as it is after this patch. > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > --- > qemu-img.c | 17 +++-------------- > 1 file changed, 3 insertions(+), 14 deletions(-) Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
On Fri, 10 Jul 2020 at 13:17, Kevin Wolf <kwolf@redhat.com> wrote: > > QEMU 2.11 introduced the --shrink option for qemu-img resize to avoid > accidentally shrinking images (commit 4ffca8904a3). However, for > compatibility reasons, it was not enforced for raw images yet, but only > a deprecation warning was printed. This warning has existed for long > enough that we can now finally require --shrink for raw images, too, and > error out if it's not given. > > Documentation already describes the state as it is after this patch. > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > --- > qemu-img.c | 17 +++-------------- > 1 file changed, 3 insertions(+), 14 deletions(-) > > diff --git a/qemu-img.c b/qemu-img.c > index e3b2ec3e78..f6a2703039 100644 > --- a/qemu-img.c > +++ b/qemu-img.c > @@ -4011,20 +4011,9 @@ static int img_resize(int argc, char **argv) > } > > if (total_size < current_size && !shrink) { > - warn_report("Shrinking an image will delete all data beyond the " > - "shrunken image's end. Before performing such an " > - "operation, make sure there is no important data there."); > - > - if (g_strcmp0(bdrv_get_format_name(blk_bs(blk)), "raw") != 0) { > - error_report( > - "Use the --shrink option to perform a shrink operation."); > - ret = -1; > - goto out; > - } else { > - warn_report("Using the --shrink option will suppress this message. " > - "Note that future versions of qemu-img may refuse to " > - "shrink images without this option."); > - } > + error_report("Use the --shrink option to perform a shrink operation."); I think it would be nice to retain this bit of text: > - warn_report("Shrinking an image will delete all data beyond the " > - "shrunken image's end. Before performing such an " > - "operation, make sure there is no important data there."); ie, make the raw-shrink case be the same as the non-raw-shrink case currently does. thanks -- PMM
Am 10.07.2020 um 14:33 hat Peter Maydell geschrieben: > On Fri, 10 Jul 2020 at 13:17, Kevin Wolf <kwolf@redhat.com> wrote: > > > > QEMU 2.11 introduced the --shrink option for qemu-img resize to avoid > > accidentally shrinking images (commit 4ffca8904a3). However, for > > compatibility reasons, it was not enforced for raw images yet, but only > > a deprecation warning was printed. This warning has existed for long > > enough that we can now finally require --shrink for raw images, too, and > > error out if it's not given. > > > > Documentation already describes the state as it is after this patch. > > > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > > --- > > qemu-img.c | 17 +++-------------- > > 1 file changed, 3 insertions(+), 14 deletions(-) > > > > diff --git a/qemu-img.c b/qemu-img.c > > index e3b2ec3e78..f6a2703039 100644 > > --- a/qemu-img.c > > +++ b/qemu-img.c > > @@ -4011,20 +4011,9 @@ static int img_resize(int argc, char **argv) > > } > > > > if (total_size < current_size && !shrink) { > > - warn_report("Shrinking an image will delete all data beyond the " > > - "shrunken image's end. Before performing such an " > > - "operation, make sure there is no important data there."); > > - > > - if (g_strcmp0(bdrv_get_format_name(blk_bs(blk)), "raw") != 0) { > > - error_report( > > - "Use the --shrink option to perform a shrink operation."); > > - ret = -1; > > - goto out; > > - } else { > > - warn_report("Using the --shrink option will suppress this message. " > > - "Note that future versions of qemu-img may refuse to " > > - "shrink images without this option."); > > - } > > + error_report("Use the --shrink option to perform a shrink operation."); > > I think it would be nice to retain this bit of text: > > > - warn_report("Shrinking an image will delete all data beyond the " > > - "shrunken image's end. Before performing such an " > > - "operation, make sure there is no important data there."); > > ie, make the raw-shrink case be the same as the non-raw-shrink > case currently does. I had this at first, but then the whole thing looked like a warning and I wasn't sure that it would still be understood as an error. (Which is of course a preexisting problem for non-raw.) Maybe it becomes clearer if I just swap the order and print the error first and only then the warning? Kevin
Am 10.07.2020 um 14:41 hat Kevin Wolf geschrieben: > Am 10.07.2020 um 14:33 hat Peter Maydell geschrieben: > > On Fri, 10 Jul 2020 at 13:17, Kevin Wolf <kwolf@redhat.com> wrote: > > > > > > QEMU 2.11 introduced the --shrink option for qemu-img resize to avoid > > > accidentally shrinking images (commit 4ffca8904a3). However, for > > > compatibility reasons, it was not enforced for raw images yet, but only > > > a deprecation warning was printed. This warning has existed for long > > > enough that we can now finally require --shrink for raw images, too, and > > > error out if it's not given. > > > > > > Documentation already describes the state as it is after this patch. > > > > > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > > > --- > > > qemu-img.c | 17 +++-------------- > > > 1 file changed, 3 insertions(+), 14 deletions(-) > > > > > > diff --git a/qemu-img.c b/qemu-img.c > > > index e3b2ec3e78..f6a2703039 100644 > > > --- a/qemu-img.c > > > +++ b/qemu-img.c > > > @@ -4011,20 +4011,9 @@ static int img_resize(int argc, char **argv) > > > } > > > > > > if (total_size < current_size && !shrink) { > > > - warn_report("Shrinking an image will delete all data beyond the " > > > - "shrunken image's end. Before performing such an " > > > - "operation, make sure there is no important data there."); > > > - > > > - if (g_strcmp0(bdrv_get_format_name(blk_bs(blk)), "raw") != 0) { > > > - error_report( > > > - "Use the --shrink option to perform a shrink operation."); > > > - ret = -1; > > > - goto out; > > > - } else { > > > - warn_report("Using the --shrink option will suppress this message. " > > > - "Note that future versions of qemu-img may refuse to " > > > - "shrink images without this option."); > > > - } > > > + error_report("Use the --shrink option to perform a shrink operation."); > > > > I think it would be nice to retain this bit of text: > > > > > - warn_report("Shrinking an image will delete all data beyond the " > > > - "shrunken image's end. Before performing such an " > > > - "operation, make sure there is no important data there."); > > > > ie, make the raw-shrink case be the same as the non-raw-shrink > > case currently does. > > I had this at first, but then the whole thing looked like a warning and > I wasn't sure that it would still be understood as an error. (Which is > of course a preexisting problem for non-raw.) > > Maybe it becomes clearer if I just swap the order and print the error > first and only then the warning? I made this change and applied the patch to the block branch. Kevin
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