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[Qemu-devel] [PATCH v6 03/25] block: Add BDS.backing_overridden
From: |
Max Reitz |
Subject: |
[Qemu-devel] [PATCH v6 03/25] block: Add BDS.backing_overridden |
Date: |
Fri, 29 Sep 2017 18:53:25 +0200 |
If the backing file is overridden, this most probably does change the
guest-visible data of a BDS. Therefore, we will need to consider this in
bdrv_refresh_filename().
Adding a new field to the BDS is not nice, but it is very simple and
exactly keeps track of whether the backing file has been overridden.
This commit adds a FIXME which will be remedied by a follow-up commit.
Until then, the respective piece of code will not result in any behavior
that is worse than what we currently have.
Signed-off-by: Max Reitz <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
---
include/block/block_int.h | 1 +
block.c | 13 +++++++++++++
block/mirror.c | 4 ++++
blockdev.c | 16 ++++++++++++++++
4 files changed, 34 insertions(+)
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 99abe2ce74..2b816ec601 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -603,6 +603,7 @@ struct BlockDriverState {
char backing_file[PATH_MAX]; /* if non zero, the image is a diff of
this file image */
char backing_format[16]; /* if non-zero and backing_file exists */
+ bool backing_overridden; /* backing file has been specified by the user */
QDict *full_open_options;
char exact_filename[PATH_MAX];
diff --git a/block.c b/block.c
index 5721168d1d..95258316ec 100644
--- a/block.c
+++ b/block.c
@@ -2196,6 +2196,11 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict
*parent_options,
reference = qdict_get_try_str(parent_options, bdref_key);
if (reference || qdict_haskey(options, "file.filename")) {
backing_filename[0] = '\0';
+
+ /* FIXME: Should also be set to true if @options contains other runtime
+ * options which control the data that is read from the backing
+ * BDS */
+ bs->backing_overridden = true;
} else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
QDECREF(options);
goto free_exit;
@@ -2396,6 +2401,9 @@ static BlockDriverState
*bdrv_append_temp_snapshot(BlockDriverState *bs,
goto out;
}
+ bs_snapshot->backing_overridden = true;
+ bdrv_refresh_filename(bs_snapshot);
+
out:
QDECREF(snapshot_options);
g_free(tmp_filename);
@@ -2526,6 +2534,7 @@ static BlockDriverState *bdrv_open_inherit(const char
*filename,
backing = qdict_get_try_str(options, "backing");
if (backing && *backing == '\0') {
flags |= BDRV_O_NO_BACKING;
+ bs->backing_overridden = true;
qdict_del(options, "backing");
}
@@ -4888,6 +4897,10 @@ void bdrv_refresh_filename(BlockDriverState *bs)
* refresh those first */
QLIST_FOREACH(child, &bs->children, next) {
bdrv_refresh_filename(child->bs);
+
+ if (child->role == &child_backing && child->bs->backing_overridden) {
+ bs->backing_overridden = true;
+ }
}
if (drv->bdrv_refresh_filename) {
diff --git a/block/mirror.c b/block/mirror.c
index 7aa873d86f..cac7490e04 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -540,6 +540,10 @@ static void mirror_exit(BlockJob *job, void *opaque)
error_report_err(local_err);
data->ret = -EPERM;
}
+
+ /* The target image's file already has been created with the backing
+ * file we just set, so there is no need to set backing_overridden or
+ * call bdrv_refresh_filename(). */
}
if (s->to_replace) {
diff --git a/blockdev.c b/blockdev.c
index 56a6b24a0b..b0393e1786 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1781,6 +1781,8 @@ static void external_snapshot_commit(BlkActionState
*common)
{
ExternalSnapshotState *state =
DO_UPCAST(ExternalSnapshotState, common, common);
+ TransactionAction *action = common->action;
+ bool image_was_existing = false;
/* We don't need (or want) to use the transactional
* bdrv_reopen_multiple() across all the entries at once, because we
@@ -1789,6 +1791,20 @@ static void external_snapshot_commit(BlkActionState
*common)
bdrv_reopen(state->old_bs, state->old_bs->open_flags & ~BDRV_O_RDWR,
NULL);
}
+
+ if (action->type == TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC) {
+ BlockdevSnapshotSync *s = action->u.blockdev_snapshot_sync.data;
+ if (s->has_mode && s->mode == NEW_IMAGE_MODE_EXISTING) {
+ image_was_existing = true;
+ }
+ } else {
+ image_was_existing = true;
+ }
+
+ if (image_was_existing) {
+ state->new_bs->backing_overridden = true;
+ bdrv_refresh_filename(state->new_bs);
+ }
}
static void external_snapshot_abort(BlkActionState *common)
--
2.13.6
- [Qemu-devel] [PATCH v6 00/25] block: Fix some filename generation issues, Max Reitz, 2017/09/29
- [Qemu-devel] [PATCH v6 01/25] block/mirror: Small absolute-paths simplification, Max Reitz, 2017/09/29
- [Qemu-devel] [PATCH v6 02/25] block: Use children list in bdrv_refresh_filename, Max Reitz, 2017/09/29
- [Qemu-devel] [PATCH v6 03/25] block: Add BDS.backing_overridden,
Max Reitz <=
- [Qemu-devel] [PATCH v6 04/25] block: Respect backing bs in bdrv_refresh_filename, Max Reitz, 2017/09/29
- [Qemu-devel] [PATCH v6 05/25] block: Make path_combine() return the path, Max Reitz, 2017/09/29
- [Qemu-devel] [PATCH v6 06/25] block: bdrv_get_full_backing_filename_from_...'s ret. val., Max Reitz, 2017/09/29
- [Qemu-devel] [PATCH v6 07/25] block: bdrv_get_full_backing_filename's ret. val., Max Reitz, 2017/09/29
- [Qemu-devel] [PATCH v6 08/25] block: Add bdrv_make_absolute_filename(), Max Reitz, 2017/09/29
- [Qemu-devel] [PATCH v6 09/25] block: Fix bdrv_find_backing_image(), Max Reitz, 2017/09/29
- [Qemu-devel] [PATCH v6 10/25] block: Add bdrv_dirname(), Max Reitz, 2017/09/29
- [Qemu-devel] [PATCH v6 11/25] blkverify: Make bdrv_dirname() return NULL, Max Reitz, 2017/09/29
- [Qemu-devel] [PATCH v6 12/25] quorum: Make bdrv_dirname() return NULL, Max Reitz, 2017/09/29
- [Qemu-devel] [PATCH v6 13/25] block/nbd: Make bdrv_dirname() return NULL, Max Reitz, 2017/09/29