Wenchao Xia <xiaw...@linux.vnet.ibm.com> writes: > This patch add function bdrv_query_snapshot_infolist(), which will
adds > return snapshot info of an image in qmp object format. The implementation > code are based on the code moved from qemu-img.c with modification to fit more implementation is based > for qmp based block layer API. > To help filter out snapshot info not needed, a call back function is > added in bdrv_query_snapshot_infolist(). > bdrv_can_read_snapshot() should be called before call this function, > to avoid got *errp set unexpectedly. "avoid getting" Not sure about "should". Couldn't a caller safely call this with a non-snapshot bs argument, and simply deal with the error? Long lines, and unusual paragraph formatting. Here's how we usually do this: This patch adds function bdrv_query_snapshot_infolist(), which will return snapshot info of an image in qmp object format. The implementation is based on the code moved from qemu-img.c with modification to fit more for qmp based block layer API. To help filter out snapshot info not needed, a call back function is added in bdrv_query_snapshot_infolist(). bdrv_can_read_snapshot() should be called before call this function, to avoid getting *errp set unexpectedly. > Signed-off-by: Wenchao Xia <xiaw...@linux.vnet.ibm.com> > Reviewed-by: Eric Blake <ebl...@redhat.com> > --- > block.c | 60 ++++++++++++++++++++++++++++++++++++++---------- > include/block/block.h | 8 +++++- > qemu-img.c | 8 +++++- > 3 files changed, 61 insertions(+), 15 deletions(-) > > diff --git a/block.c b/block.c > index 368b37c..8d0145a 100644 > --- a/block.c > +++ b/block.c > @@ -2813,29 +2813,62 @@ int coroutine_fn > bdrv_co_is_allocated_above(BlockDriverState *top, > return 0; > } > > -void collect_snapshots(BlockDriverState *bs , ImageInfo *info) > +SnapshotInfoList *bdrv_query_snapshot_infolist(BlockDriverState *bs, > + SnapshotFilterFunc filter, > + void *opaque, > + Error **errp) > { > int i, sn_count; > QEMUSnapshotInfo *sn_tab = NULL; > - SnapshotInfoList *info_list, *cur_item = NULL; > + SnapshotInfoList *info_list, *cur_item = NULL, *head = NULL; > + SnapshotInfo *info; > + > sn_count = bdrv_snapshot_list(bs, &sn_tab); > + if (sn_count < 0) { > + /* Now bdrv_snapshot_list() use negative value to tip error, so a > check > + * of it was done here. In future errp can be set by that function > + * itself, by changing the call back functions in c files in ./block. > + */ I doubt we need this comment. > + const char *dev = bdrv_get_device_name(bs); > + switch (sn_count) { > + case -ENOMEDIUM: > + error_setg(errp, "Device '%s' is not inserted.", dev); We generally don't end error messages with a period. Please remove it from this and other messages. > + break; > + case -ENOTSUP: > + error_setg(errp, > + "Device '%s' does not support internal snapshot.", internal snapshots > + dev); > + break; > + default: > + error_setg(errp, > + "Device '%s' got '%d' for bdrv_snapshot_list(), " > + "message '%s'.", > + dev, sn_count, strerror(-sn_count)); error_setg(errp, "Can't list snapshots of device '%s': %s", dev, sterror(-sn_count)); > + break; > + } > + return NULL; > + } > > for (i = 0; i < sn_count; i++) { > - info->has_snapshots = true; > - info_list = g_new0(SnapshotInfoList, 1); > + if (filter && filter(&sn_tab[i], opaque) != 0) { > + continue; > + } Is the filter feature really worth it? If yes, should it be added in a separate patch? > > - info_list->value = g_new0(SnapshotInfo, 1); > - info_list->value->id = g_strdup(sn_tab[i].id_str); > - info_list->value->name = g_strdup(sn_tab[i].name); > - info_list->value->vm_state_size = sn_tab[i].vm_state_size; > - info_list->value->date_sec = sn_tab[i].date_sec; > - info_list->value->date_nsec = sn_tab[i].date_nsec; > - info_list->value->vm_clock_sec = sn_tab[i].vm_clock_nsec / > 1000000000; > - info_list->value->vm_clock_nsec = sn_tab[i].vm_clock_nsec % > 1000000000; > + info = g_new0(SnapshotInfo, 1); > + info->id = g_strdup(sn_tab[i].id_str); > + info->name = g_strdup(sn_tab[i].name); > + info->vm_state_size = sn_tab[i].vm_state_size; > + info->date_sec = sn_tab[i].date_sec; > + info->date_nsec = sn_tab[i].date_nsec; > + info->vm_clock_sec = sn_tab[i].vm_clock_nsec / 1000000000; > + info->vm_clock_nsec = sn_tab[i].vm_clock_nsec % 1000000000; > + > + info_list = g_new0(SnapshotInfoList, 1); > + info_list->value = info; > > /* XXX: waiting for the qapi to support qemu-queue.h types */ > if (!cur_item) { > - info->snapshots = cur_item = info_list; > + head = cur_item = info_list; > } else { > cur_item->next = info_list; > cur_item = info_list; > @@ -2844,6 +2877,7 @@ void collect_snapshots(BlockDriverState *bs , ImageInfo > *info) > } > > g_free(sn_tab); > + return head; > } > > void collect_image_info(BlockDriverState *bs, > diff --git a/include/block/block.h b/include/block/block.h > index e6d915c..51a14f2 100644 > --- a/include/block/block.h > +++ b/include/block/block.h > @@ -319,6 +319,13 @@ void bdrv_get_backing_filename(BlockDriverState *bs, > char *filename, int filename_size); > void bdrv_get_full_backing_filename(BlockDriverState *bs, > char *dest, size_t sz); > + > +typedef int (*SnapshotFilterFunc)(const QEMUSnapshotInfo *sn, void *opaque); > +/* assume bs is already opened, use qapi_free_* to free returned value. */ Pretty much all functions assume bs is open, hardly worth a comment. > +SnapshotInfoList *bdrv_query_snapshot_infolist(BlockDriverState *bs, > + SnapshotFilterFunc filter, > + void *opaque, > + Error **errp); > BlockInfo *bdrv_query_info(BlockDriverState *s); > BlockStats *bdrv_query_stats(const BlockDriverState *bs); > bool bdrv_can_read_snapshot(BlockDriverState *bs); > @@ -450,7 +457,6 @@ int bdrv_debug_breakpoint(BlockDriverState *bs, const > char *event, > int bdrv_debug_resume(BlockDriverState *bs, const char *tag); > bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag); > > -void collect_snapshots(BlockDriverState *bs , ImageInfo *info); > void collect_image_info(BlockDriverState *bs, > ImageInfo *info, > const char *filename); > diff --git a/qemu-img.c b/qemu-img.c > index b650d17..1034cc5 100644 > --- a/qemu-img.c > +++ b/qemu-img.c > @@ -1280,7 +1280,13 @@ static ImageInfoList *collect_image_info_list(const > char *filename, > > info = g_new0(ImageInfo, 1); > collect_image_info(bs, info, filename); > - collect_snapshots(bs, info); > + if (bdrv_can_read_snapshot(bs)) { > + info->snapshots = bdrv_query_snapshot_infolist(bs, NULL, > + NULL, NULL); > + if (info->snapshots) { > + info->has_snapshots = true; > + } > + } > > elem = g_new0(ImageInfoList, 1); > elem->value = info; Silently ignores errors, but the old code does so, too. QAPI's has_FOO is pointless when FOO is a pointer. Not your fault.