| Message ID | 1453917600-2663-7-git-send-email-mreitz@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 01/27 18:59, Max Reitz wrote: > The NBD code uses the BDS close notifier to determine when a medium is > ejected. However, now it should use the BB's BDS removal notifier for > that instead of the BDS's close notifier. > > Signed-off-by: Max Reitz <mreitz@redhat.com> > --- > blockdev-nbd.c | 40 +++++----------------------------------- > nbd/server.c | 13 +++++++++++++ > 2 files changed, 18 insertions(+), 35 deletions(-) > > diff --git a/blockdev-nbd.c b/blockdev-nbd.c > index 4a758ac..9d6a21c 100644 > --- a/blockdev-nbd.c > +++ b/blockdev-nbd.c > @@ -45,37 +45,11 @@ void qmp_nbd_server_start(SocketAddress *addr, Error **errp) > } > } > > -/* > - * Hook into the BlockBackend notifiers to close the export when the > - * backend is closed. > - */ > -typedef struct NBDCloseNotifier { > - Notifier n; > - NBDExport *exp; > - QTAILQ_ENTRY(NBDCloseNotifier) next; > -} NBDCloseNotifier; > - > -static QTAILQ_HEAD(, NBDCloseNotifier) close_notifiers = > - QTAILQ_HEAD_INITIALIZER(close_notifiers); > - > -static void nbd_close_notifier(Notifier *n, void *data) > -{ > - NBDCloseNotifier *cn = DO_UPCAST(NBDCloseNotifier, n, n); > - > - notifier_remove(&cn->n); > - QTAILQ_REMOVE(&close_notifiers, cn, next); > - > - nbd_export_close(cn->exp); > - nbd_export_put(cn->exp); > - g_free(cn); > -} > - > void qmp_nbd_server_add(const char *device, bool has_writable, bool writable, > Error **errp) > { > BlockBackend *blk; > NBDExport *exp; > - NBDCloseNotifier *n; > > if (server_fd == -1) { > error_setg(errp, "NBD server not running"); > @@ -113,19 +87,15 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable, > > nbd_export_set_name(exp, device); > > - n = g_new0(NBDCloseNotifier, 1); > - n->n.notify = nbd_close_notifier; > - n->exp = exp; > - blk_add_close_notifier(blk, &n->n); > - QTAILQ_INSERT_TAIL(&close_notifiers, n, next); > + /* The list of named exports has a strong reference to this export now and > + * our only way of accessing it is through nbd_export_find(), so we can drop > + * the strong reference that is @exp. */ Not quite sure about the meaning of "the strong reference that is @exp", I guess you mean the one reference born in nbd_export_new(), which would match the code. Other than this, Reviewed-by: Fam Zheng <famz@redhat.com>
On 28.01.2016 04:26, Fam Zheng wrote: > On Wed, 01/27 18:59, Max Reitz wrote: >> The NBD code uses the BDS close notifier to determine when a medium is >> ejected. However, now it should use the BB's BDS removal notifier for >> that instead of the BDS's close notifier. >> >> Signed-off-by: Max Reitz <mreitz@redhat.com> >> --- >> blockdev-nbd.c | 40 +++++----------------------------------- >> nbd/server.c | 13 +++++++++++++ >> 2 files changed, 18 insertions(+), 35 deletions(-) >> >> diff --git a/blockdev-nbd.c b/blockdev-nbd.c >> index 4a758ac..9d6a21c 100644 >> --- a/blockdev-nbd.c >> +++ b/blockdev-nbd.c >> @@ -45,37 +45,11 @@ void qmp_nbd_server_start(SocketAddress *addr, Error **errp) >> } >> } >> >> -/* >> - * Hook into the BlockBackend notifiers to close the export when the >> - * backend is closed. >> - */ >> -typedef struct NBDCloseNotifier { >> - Notifier n; >> - NBDExport *exp; >> - QTAILQ_ENTRY(NBDCloseNotifier) next; >> -} NBDCloseNotifier; >> - >> -static QTAILQ_HEAD(, NBDCloseNotifier) close_notifiers = >> - QTAILQ_HEAD_INITIALIZER(close_notifiers); >> - >> -static void nbd_close_notifier(Notifier *n, void *data) >> -{ >> - NBDCloseNotifier *cn = DO_UPCAST(NBDCloseNotifier, n, n); >> - >> - notifier_remove(&cn->n); >> - QTAILQ_REMOVE(&close_notifiers, cn, next); >> - >> - nbd_export_close(cn->exp); >> - nbd_export_put(cn->exp); >> - g_free(cn); >> -} >> - >> void qmp_nbd_server_add(const char *device, bool has_writable, bool writable, >> Error **errp) >> { >> BlockBackend *blk; >> NBDExport *exp; >> - NBDCloseNotifier *n; >> >> if (server_fd == -1) { >> error_setg(errp, "NBD server not running"); >> @@ -113,19 +87,15 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable, >> >> nbd_export_set_name(exp, device); >> >> - n = g_new0(NBDCloseNotifier, 1); >> - n->n.notify = nbd_close_notifier; >> - n->exp = exp; >> - blk_add_close_notifier(blk, &n->n); >> - QTAILQ_INSERT_TAIL(&close_notifiers, n, next); >> + /* The list of named exports has a strong reference to this export now and >> + * our only way of accessing it is through nbd_export_find(), so we can drop >> + * the strong reference that is @exp. */ > > Not quite sure about the meaning of "the strong reference that is @exp", I > guess you mean the one reference born in nbd_export_new(), which would match > the code. Other than this, Yes, the reference returned by nbd_export_new(), which is then stored in @exp. This is a strong reference, so once @exp goes out of scope, the reference counter has to be decremented. Max > Reviewed-by: Fam Zheng <famz@redhat.com>
diff --git a/blockdev-nbd.c b/blockdev-nbd.c index 4a758ac..9d6a21c 100644 --- a/blockdev-nbd.c +++ b/blockdev-nbd.c @@ -45,37 +45,11 @@ void qmp_nbd_server_start(SocketAddress *addr, Error **errp) } } -/* - * Hook into the BlockBackend notifiers to close the export when the - * backend is closed. - */ -typedef struct NBDCloseNotifier { - Notifier n; - NBDExport *exp; - QTAILQ_ENTRY(NBDCloseNotifier) next; -} NBDCloseNotifier; - -static QTAILQ_HEAD(, NBDCloseNotifier) close_notifiers = - QTAILQ_HEAD_INITIALIZER(close_notifiers); - -static void nbd_close_notifier(Notifier *n, void *data) -{ - NBDCloseNotifier *cn = DO_UPCAST(NBDCloseNotifier, n, n); - - notifier_remove(&cn->n); - QTAILQ_REMOVE(&close_notifiers, cn, next); - - nbd_export_close(cn->exp); - nbd_export_put(cn->exp); - g_free(cn); -} - void qmp_nbd_server_add(const char *device, bool has_writable, bool writable, Error **errp) { BlockBackend *blk; NBDExport *exp; - NBDCloseNotifier *n; if (server_fd == -1) { error_setg(errp, "NBD server not running"); @@ -113,19 +87,15 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable, nbd_export_set_name(exp, device); - n = g_new0(NBDCloseNotifier, 1); - n->n.notify = nbd_close_notifier; - n->exp = exp; - blk_add_close_notifier(blk, &n->n); - QTAILQ_INSERT_TAIL(&close_notifiers, n, next); + /* The list of named exports has a strong reference to this export now and + * our only way of accessing it is through nbd_export_find(), so we can drop + * the strong reference that is @exp. */ + nbd_export_put(exp); } void qmp_nbd_server_stop(Error **errp) { - while (!QTAILQ_EMPTY(&close_notifiers)) { - NBDCloseNotifier *cn = QTAILQ_FIRST(&close_notifiers); - nbd_close_notifier(&cn->n, nbd_export_get_blockdev(cn->exp)); - } + nbd_export_close_all(); if (server_fd != -1) { qemu_set_fd_handler(server_fd, NULL, NULL, NULL); diff --git a/nbd/server.c b/nbd/server.c index 5169b59..2045f7c 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -64,6 +64,8 @@ struct NBDExport { QTAILQ_ENTRY(NBDExport) next; AioContext *ctx; + + Notifier eject_notifier; }; static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); @@ -644,6 +646,12 @@ static void blk_aio_detach(void *opaque) exp->ctx = NULL; } +static void nbd_eject_notifier(Notifier *n, void *data) +{ + NBDExport *exp = container_of(n, NBDExport, eject_notifier); + nbd_export_close(exp); +} + NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size, uint32_t nbdflags, void (*close)(NBDExport *), Error **errp) @@ -666,6 +674,10 @@ NBDExport *nbd_export_new(BlockBackend *blk, off_t dev_offset, off_t size, exp->ctx = blk_get_aio_context(blk); blk_ref(blk); blk_add_aio_context_notifier(blk, blk_aio_attached, blk_aio_detach, exp); + + exp->eject_notifier.notify = nbd_eject_notifier; + blk_add_remove_bs_notifier(blk, &exp->eject_notifier); + /* * NBD exports are used for non-shared storage migration. Make sure * that BDRV_O_INACTIVE is cleared and the image is ready for write @@ -745,6 +757,7 @@ void nbd_export_put(NBDExport *exp) } if (exp->blk) { + notifier_remove(&exp->eject_notifier); blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach, exp); blk_unref(exp->blk);
The NBD code uses the BDS close notifier to determine when a medium is ejected. However, now it should use the BB's BDS removal notifier for that instead of the BDS's close notifier. Signed-off-by: Max Reitz <mreitz@redhat.com> --- blockdev-nbd.c | 40 +++++----------------------------------- nbd/server.c | 13 +++++++++++++ 2 files changed, 18 insertions(+), 35 deletions(-)