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authorStefan Hajnoczi <stefanha@redhat.com>2018-03-06 20:48:18 +0000
committerEric Blake <eblake@redhat.com>2018-03-13 15:38:55 -0500
commitd03654eacdf35f436fbe78ca46cea215d5165ab5 (patch)
tree0641a1398fb1b43f9a2e54fbbef07d6080d56568 /block
parent65529782f8fec531fd114cc0f58399e88202153c (diff)
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block: let blk_add/remove_aio_context_notifier() tolerate BDS changes
Commit 2019ba0a0197 ("block: Add AioContextNotifier functions to BB") added blk_add/remove_aio_context_notifier() and implemented them by passing through the bdrv_*() equivalent. This doesn't work across bdrv_append(), which detaches child->bs and re-attaches it to a new BlockDriverState. When blk_remove_aio_context_notifier() is called we will access the new BDS instead of the one where the notifier was added! >From the point of view of the blk_*() API user, changes to the root BDS should be transparent. This patch maintains a list of AioContext notifiers in BlockBackend and adds/removes them from the BlockDriverState as needed. Reported-by: Stefano Panella <spanella@gmail.com> Cc: Max Reitz <mreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20180306204819.11266-2-stefanha@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
Diffstat (limited to 'block')
-rw-r--r--block/block-backend.c63
-rw-r--r--block/trace-events2
2 files changed, 65 insertions, 0 deletions
diff --git a/block/block-backend.c b/block/block-backend.c
index f2e0a85..681b240 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -31,6 +31,13 @@
static AioContext *blk_aiocb_get_aio_context(BlockAIOCB *acb);
+typedef struct BlockBackendAioNotifier {
+ void (*attached_aio_context)(AioContext *new_context, void *opaque);
+ void (*detach_aio_context)(void *opaque);
+ void *opaque;
+ QLIST_ENTRY(BlockBackendAioNotifier) list;
+} BlockBackendAioNotifier;
+
struct BlockBackend {
char *name;
int refcnt;
@@ -69,6 +76,7 @@ struct BlockBackend {
bool allow_write_beyond_eof;
NotifierList remove_bs_notifiers, insert_bs_notifiers;
+ QLIST_HEAD(, BlockBackendAioNotifier) aio_notifiers;
int quiesce_counter;
VMChangeStateEntry *vmsh;
@@ -247,6 +255,36 @@ static int blk_root_inactivate(BdrvChild *child)
return 0;
}
+static void blk_root_attach(BdrvChild *child)
+{
+ BlockBackend *blk = child->opaque;
+ BlockBackendAioNotifier *notifier;
+
+ trace_blk_root_attach(child, blk, child->bs);
+
+ QLIST_FOREACH(notifier, &blk->aio_notifiers, list) {
+ bdrv_add_aio_context_notifier(child->bs,
+ notifier->attached_aio_context,
+ notifier->detach_aio_context,
+ notifier->opaque);
+ }
+}
+
+static void blk_root_detach(BdrvChild *child)
+{
+ BlockBackend *blk = child->opaque;
+ BlockBackendAioNotifier *notifier;
+
+ trace_blk_root_detach(child, blk, child->bs);
+
+ QLIST_FOREACH(notifier, &blk->aio_notifiers, list) {
+ bdrv_remove_aio_context_notifier(child->bs,
+ notifier->attached_aio_context,
+ notifier->detach_aio_context,
+ notifier->opaque);
+ }
+}
+
static const BdrvChildRole child_root = {
.inherit_options = blk_root_inherit_options,
@@ -260,6 +298,9 @@ static const BdrvChildRole child_root = {
.activate = blk_root_activate,
.inactivate = blk_root_inactivate,
+
+ .attach = blk_root_attach,
+ .detach = blk_root_detach,
};
/*
@@ -287,6 +328,7 @@ BlockBackend *blk_new(uint64_t perm, uint64_t shared_perm)
notifier_list_init(&blk->remove_bs_notifiers);
notifier_list_init(&blk->insert_bs_notifiers);
+ QLIST_INIT(&blk->aio_notifiers);
QTAILQ_INSERT_TAIL(&block_backends, blk, link);
return blk;
@@ -364,6 +406,7 @@ static void blk_delete(BlockBackend *blk)
}
assert(QLIST_EMPTY(&blk->remove_bs_notifiers.notifiers));
assert(QLIST_EMPTY(&blk->insert_bs_notifiers.notifiers));
+ assert(QLIST_EMPTY(&blk->aio_notifiers));
QTAILQ_REMOVE(&block_backends, blk, link);
drive_info_del(blk->legacy_dinfo);
block_acct_cleanup(&blk->stats);
@@ -1857,8 +1900,15 @@ void blk_add_aio_context_notifier(BlockBackend *blk,
void (*attached_aio_context)(AioContext *new_context, void *opaque),
void (*detach_aio_context)(void *opaque), void *opaque)
{
+ BlockBackendAioNotifier *notifier;
BlockDriverState *bs = blk_bs(blk);
+ notifier = g_new(BlockBackendAioNotifier, 1);
+ notifier->attached_aio_context = attached_aio_context;
+ notifier->detach_aio_context = detach_aio_context;
+ notifier->opaque = opaque;
+ QLIST_INSERT_HEAD(&blk->aio_notifiers, notifier, list);
+
if (bs) {
bdrv_add_aio_context_notifier(bs, attached_aio_context,
detach_aio_context, opaque);
@@ -1871,12 +1921,25 @@ void blk_remove_aio_context_notifier(BlockBackend *blk,
void (*detach_aio_context)(void *),
void *opaque)
{
+ BlockBackendAioNotifier *notifier;
BlockDriverState *bs = blk_bs(blk);
if (bs) {
bdrv_remove_aio_context_notifier(bs, attached_aio_context,
detach_aio_context, opaque);
}
+
+ QLIST_FOREACH(notifier, &blk->aio_notifiers, list) {
+ if (notifier->attached_aio_context == attached_aio_context &&
+ notifier->detach_aio_context == detach_aio_context &&
+ notifier->opaque == opaque) {
+ QLIST_REMOVE(notifier, list);
+ g_free(notifier);
+ return;
+ }
+ }
+
+ abort();
}
void blk_add_remove_bs_notifier(BlockBackend *blk, Notifier *notify)
diff --git a/block/trace-events b/block/trace-events
index 02dd80f..7493d52 100644
--- a/block/trace-events
+++ b/block/trace-events
@@ -7,6 +7,8 @@ bdrv_lock_medium(void *bs, bool locked) "bs %p locked %d"
# block/block-backend.c
blk_co_preadv(void *blk, void *bs, int64_t offset, unsigned int bytes, int flags) "blk %p bs %p offset %"PRId64" bytes %u flags 0x%x"
blk_co_pwritev(void *blk, void *bs, int64_t offset, unsigned int bytes, int flags) "blk %p bs %p offset %"PRId64" bytes %u flags 0x%x"
+blk_root_attach(void *child, void *blk, void *bs) "child %p blk %p bs %p"
+blk_root_detach(void *child, void *blk, void *bs) "child %p blk %p bs %p"
# block/io.c
bdrv_co_preadv(void *bs, int64_t offset, int64_t nbytes, unsigned int flags) "bs %p offset %"PRId64" nbytes %"PRId64" flags 0x%x"