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Re: [PATCH v4 04/25] include/sysemu/block-backend: split header into I/O
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From: |
Hanna Reitz |
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Subject: |
Re: [PATCH v4 04/25] include/sysemu/block-backend: split header into I/O and global state (GS) API |
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Date: |
Fri, 12 Nov 2021 11:23:31 +0100 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 |
On 25.10.21 12:17, Emanuele Giuseppe Esposito wrote:
Similarly to the previous patches, split block-backend.h
in block-backend-io.h and block-backend-global-state.h
In addition, remove "block/block.h" include as it seems
it is not necessary anymore, together with "qemu/iov.h"
block-backend-common.h contains the structures shared between
the two headers, and the functions that can't be categorized as
I/O or global state.
Assertions are added in the next patch.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
block/block-backend.c | 9 +-
include/sysemu/block-backend-common.h | 74 ++++++
include/sysemu/block-backend-global-state.h | 122 +++++++++
include/sysemu/block-backend-io.h | 139 ++++++++++
include/sysemu/block-backend.h | 269 +-------------------
5 files changed, 344 insertions(+), 269 deletions(-)
create mode 100644 include/sysemu/block-backend-common.h
create mode 100644 include/sysemu/block-backend-global-state.h
create mode 100644 include/sysemu/block-backend-io.h
diff --git a/block/block-backend.c b/block/block-backend.c
index 39cd99df2b..0afc03fd66 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -79,6 +79,7 @@ struct BlockBackend {
bool allow_aio_context_change;
bool allow_write_beyond_eof;
+ /* Protected by BQL lock */
NotifierList remove_bs_notifiers, insert_bs_notifiers;
QLIST_HEAD(, BlockBackendAioNotifier) aio_notifiers;
@@ -111,12 +112,14 @@ static const AIOCBInfo block_backend_aiocb_info = {
static void drive_info_del(DriveInfo *dinfo);
static BlockBackend *bdrv_first_blk(BlockDriverState *bs);
-/* All BlockBackends */
+/* All BlockBackends. Protected by BQL lock. */
static QTAILQ_HEAD(, BlockBackend) block_backends =
QTAILQ_HEAD_INITIALIZER(block_backends);
-/* All BlockBackends referenced by the monitor and which are iterated through by
- * blk_next() */
+/*
+ * All BlockBackends referenced by the monitor and which are iterated through
by
+ * blk_next(). Protected by BQL lock.
+ */
static QTAILQ_HEAD(, BlockBackend) monitor_block_backends =
QTAILQ_HEAD_INITIALIZER(monitor_block_backends);
diff --git a/include/sysemu/block-backend-common.h b/include/sysemu/block-backend-common.h
new file mode 100644
index 0000000000..52ff6a4d26
--- /dev/null
+++ b/include/sysemu/block-backend-common.h
@@ -0,0 +1,74 @@
+/*
+ * QEMU Block backends
+ *
+ * Copyright (C) 2014-2016 Red Hat, Inc.
+ *
+ * Authors:
+ * Markus Armbruster <armbru@redhat.com>,
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1
+ * or later. See the COPYING.LIB file in the top-level directory.
+ */
+
+#ifndef BLOCK_BACKEND_COMMON_H
+#define BLOCK_BACKEND_COMMON_H
+
+#include "block/throttle-groups.h"
+
+/* Callbacks for block device models */
+typedef struct BlockDevOps {
+ /*
+ * Runs when virtual media changed (monitor commands eject, change)
+ * Argument load is true on load and false on eject.
+ * Beware: doesn't run when a host device's physical media
+ * changes. Sure would be useful if it did.
+ * Device models with removable media must implement this callback.
+ */
+ void (*change_media_cb)(void *opaque, bool load, Error **errp);
+ /*
+ * Runs when an eject request is issued from the monitor, the tray
+ * is closed, and the medium is locked.
+ * Device models that do not implement is_medium_locked will not need
+ * this callback. Device models that can lock the medium or tray might
+ * want to implement the callback and unlock the tray when "force" is
+ * true, even if they do not support eject requests.
+ */
+ void (*eject_request_cb)(void *opaque, bool force);
+ /*
+ * Is the virtual tray open?
+ * Device models implement this only when the device has a tray.
+ */
+ bool (*is_tray_open)(void *opaque);
+ /*
+ * Is the virtual medium locked into the device?
+ * Device models implement this only when device has such a lock.
+ */
+ bool (*is_medium_locked)(void *opaque);
+ /*
+ * Runs when the size changed (e.g. monitor command block_resize)
+ */
+ void (*resize_cb)(void *opaque);
+ /*
+ * Runs when the backend receives a drain request.
+ */
+ void (*drained_begin)(void *opaque);
+ /*
+ * Runs when the backend's last drain request ends.
+ */
+ void (*drained_end)(void *opaque);
+ /*
+ * Is the device still busy?
+ */
+ bool (*drained_poll)(void *opaque);
+} BlockDevOps;
+
+/*
+ * This struct is embedded in (the private) BlockBackend struct and contains
+ * fields that must be public. This is in particular for QLIST_ENTRY() and
+ * friends so that BlockBackends can be kept in lists outside block-backend.c
+ */
+typedef struct BlockBackendPublic {
+ ThrottleGroupMember throttle_group_member;
+} BlockBackendPublic;
+
+#endif /* BLOCK_BACKEND_COMMON_H */
diff --git a/include/sysemu/block-backend-global-state.h
b/include/sysemu/block-backend-global-state.h
new file mode 100644
index 0000000000..4001b1c02a
--- /dev/null
+++ b/include/sysemu/block-backend-global-state.h
@@ -0,0 +1,122 @@
+/*
+ * QEMU Block backends
+ *
+ * Copyright (C) 2014-2016 Red Hat, Inc.
+ *
+ * Authors:
+ * Markus Armbruster <armbru@redhat.com>,
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1
+ * or later. See the COPYING.LIB file in the top-level directory.
+ */
+
+#ifndef BLOCK_BACKEND_GS_H
+#define BLOCK_BACKEND_GS_H
+
+#include "block-backend-common.h"
+
+/*
+ * Global state (GS) API. These functions run under the BQL lock.
+ *
+ * See include/block/block-global-state.h for more information about
+ * the GS API.
+ */
+
+BlockBackend *blk_new(AioContext *ctx, uint64_t perm, uint64_t shared_perm);
+BlockBackend *blk_new_with_bs(BlockDriverState *bs, uint64_t perm,
+ uint64_t shared_perm, Error **errp);
+BlockBackend *blk_new_open(const char *filename, const char *reference,
+ QDict *options, int flags, Error **errp);
+int blk_get_refcnt(BlockBackend *blk);
+void blk_ref(BlockBackend *blk);
+void blk_unref(BlockBackend *blk);
+void blk_remove_all_bs(void);
+const char *blk_name(const BlockBackend *blk);
This is called by send_qmp_error_event(), which in turn is called by
blk_error_action(). Are those strictly main loop functions?
+BlockBackend *blk_by_name(const char *name);
+BlockBackend *blk_next(BlockBackend *blk);
+BlockBackend *blk_all_next(BlockBackend *blk);
+bool monitor_add_blk(BlockBackend *blk, const char *name, Error **errp);
+void monitor_remove_blk(BlockBackend *blk);
+
+BlockBackendPublic *blk_get_public(BlockBackend *blk);
+BlockBackend *blk_by_public(BlockBackendPublic *public);
+
+void blk_remove_bs(BlockBackend *blk);
+int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs, Error **errp);
+bool bdrv_has_blk(BlockDriverState *bs);
+bool bdrv_is_root_node(BlockDriverState *bs);
+int blk_set_perm(BlockBackend *blk, uint64_t perm, uint64_t shared_perm,
+ Error **errp);
+void blk_get_perm(BlockBackend *blk, uint64_t *perm, uint64_t *shared_perm);
These functions are called from fuse_do_truncate(), which I believe runs
in the context of the export’s BlockBackend. I’m not saying that’s
necessarily correct, but as of the next patch, this happens:
$ touch /tmp/fuse-export
$ storage-daemon/qemu-storage-daemon \
--object iothread,id=iothr0 \
--blockdev file,node-name=node0,filename=/tmp/fuse-export \
--export
fuse,id=exp0,node-name=node0,mountpoint=/tmp/fuse-export,iothread=iothr0,writable=true
\
&
[1] 27395
$ truncate /tmp/fuse-export -s 1M
qemu-storage-daemon: ../block/block-backend.c:935: blk_get_perm:
Assertion `qemu_in_main_thread()' failed.
truncate: failed to truncate '/tmp/fuse-export' at 1048576 bytes:
Software caused connection abort
truncate: failed to close '/tmp/fuse-export': Transport endpoint is not
connected
[1] + 27395 IOT instruction (core dumped)
storage-daemon/qemu-storage-daemon --object iothread,id=iothr0 --blockdev
+
+void blk_iostatus_enable(BlockBackend *blk);
+bool blk_iostatus_is_enabled(const BlockBackend *blk);
+BlockDeviceIoStatus blk_iostatus(const BlockBackend *blk);
+void blk_iostatus_disable(BlockBackend *blk);
+void blk_iostatus_reset(BlockBackend *blk);
+void blk_iostatus_set_err(BlockBackend *blk, int error);
+int blk_attach_dev(BlockBackend *blk, DeviceState *dev);
+void blk_detach_dev(BlockBackend *blk, DeviceState *dev);
+DeviceState *blk_get_attached_dev(BlockBackend *blk);
+char *blk_get_attached_dev_id(BlockBackend *blk);
+BlockBackend *blk_by_dev(void *dev);
+BlockBackend *blk_by_qdev_id(const char *id, Error **errp);
+void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops, void *opaque);
+
+int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags);
+int64_t blk_nb_sectors(BlockBackend *blk);
I’d have considered this an I/O function, and blk_getlength() is
classified as such. Why not this?
+int blk_commit_all(void);
+void blk_drain(BlockBackend *blk);
I’m again wondering a bit why this is a GS function, when
bdrv_drained_begin() is an I/O function. However, less than in the case
of bdrv_drain(), given that there is no blk_drained_begin() that’s
classified as I/O.
+void blk_drain_all(void);
+void blk_set_on_error(BlockBackend *blk, BlockdevOnError on_read_error,
+ BlockdevOnError on_write_error);
+bool blk_supports_write_perm(BlockBackend *blk);
+bool blk_is_sg(BlockBackend *blk);
+bool blk_enable_write_cache(BlockBackend *blk);
+void blk_set_enable_write_cache(BlockBackend *blk, bool wce);
+void blk_lock_medium(BlockBackend *blk, bool locked);
+void blk_eject(BlockBackend *blk, bool eject_flag);
+int blk_get_flags(BlockBackend *blk);
+void blk_set_guest_block_size(BlockBackend *blk, int align);
+bool blk_op_is_blocked(BlockBackend *blk, BlockOpType op, Error **errp);
+void blk_op_unblock(BlockBackend *blk, BlockOpType op, Error *reason);
+void blk_op_block_all(BlockBackend *blk, Error *reason);
+void blk_op_unblock_all(BlockBackend *blk, Error *reason);
+int blk_set_aio_context(BlockBackend *blk, AioContext *new_context,
+ Error **errp);
+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);
+void blk_remove_aio_context_notifier(BlockBackend *blk,
+ void (*attached_aio_context)(AioContext *,
+ void *),
+ void (*detach_aio_context)(void *),
+ void *opaque);
+void blk_add_remove_bs_notifier(BlockBackend *blk, Notifier *notify);
+void blk_add_insert_bs_notifier(BlockBackend *blk, Notifier *notify);
+BlockBackendRootState *blk_get_root_state(BlockBackend *blk);
+void blk_update_root_state(BlockBackend *blk);
+bool blk_get_detect_zeroes_from_root_state(BlockBackend *blk);
+int blk_get_open_flags_from_root_state(BlockBackend *blk);
+
+int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf,
+ int64_t pos, int size);
+int blk_load_vmstate(BlockBackend *blk, uint8_t *buf, int64_t pos, int size);
+int blk_probe_blocksizes(BlockBackend *blk, BlockSizes *bsz);
+int blk_probe_geometry(BlockBackend *blk, HDGeometry *geo);
+BlockAIOCB *blk_abort_aio_request(BlockBackend *blk,
+ BlockCompletionFunc *cb,
+ void *opaque, int ret);
This sounds more like an I/O function to me.
+
+void blk_set_io_limits(BlockBackend *blk, ThrottleConfig *cfg);
+void blk_io_limits_disable(BlockBackend *blk);
+void blk_io_limits_enable(BlockBackend *blk, const char *group);
+void blk_io_limits_update_group(BlockBackend *blk, const char *group);
+void blk_set_force_allow_inactivate(BlockBackend *blk);
+
+void blk_register_buf(BlockBackend *blk, void *host, size_t size);
+void blk_unregister_buf(BlockBackend *blk, void *host);
+
+const BdrvChild *blk_root(BlockBackend *blk);
+
+#endif /* BLOCK_BACKEND_GS_H */
diff --git a/include/sysemu/block-backend-io.h
b/include/sysemu/block-backend-io.h
new file mode 100644
index 0000000000..ab0463cb69
--- /dev/null
+++ b/include/sysemu/block-backend-io.h
@@ -0,0 +1,139 @@
+/*
+ * QEMU Block backends
+ *
+ * Copyright (C) 2014-2016 Red Hat, Inc.
+ *
+ * Authors:
+ * Markus Armbruster <armbru@redhat.com>,
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1
+ * or later. See the COPYING.LIB file in the top-level directory.
+ */
+
+#ifndef BLOCK_BACKEND_IO_H
+#define BLOCK_BACKEND_IO_H
+
+#include "block-backend-common.h"
+
+/*
+ * I/O API functions. These functions are thread-safe.
+ *
+ * See include/block/block-io.h for more information about
+ * the I/O API.
+ */
+
+BlockDriverState *blk_bs(BlockBackend *blk);
+
+int blk_replace_bs(BlockBackend *blk, BlockDriverState *new_bs, Error **errp);
This sounds like a GS function to me.
+
+void blk_set_allow_write_beyond_eof(BlockBackend *blk, bool allow);
+void blk_set_allow_aio_context_change(BlockBackend *blk, bool allow);
+void blk_set_disable_request_queuing(BlockBackend *blk, bool disable);
+
+int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int bytes);
+int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int bytes,
+ BdrvRequestFlags flags);
+int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset,
+ int64_t bytes, QEMUIOVector *qiov,
+ BdrvRequestFlags flags);
+int coroutine_fn blk_co_pwritev_part(BlockBackend *blk, int64_t offset,
+ int64_t bytes,
+ QEMUIOVector *qiov, size_t qiov_offset,
+ BdrvRequestFlags flags);
+int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset,
+ int64_t bytes, QEMUIOVector *qiov,
+ BdrvRequestFlags flags);
+
+static inline int coroutine_fn blk_co_pread(BlockBackend *blk, int64_t offset,
+ int64_t bytes, void *buf,
+ BdrvRequestFlags flags)
+{
+ QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
+
+ assert(bytes <= SIZE_MAX);
+
+ return blk_co_preadv(blk, offset, bytes, &qiov, flags);
+}
+
+static inline int coroutine_fn blk_co_pwrite(BlockBackend *blk, int64_t offset,
+ int64_t bytes, void *buf,
+ BdrvRequestFlags flags)
+{
+ QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
+
+ assert(bytes <= SIZE_MAX);
+
+ return blk_co_pwritev(blk, offset, bytes, &qiov, flags);
+}
+
+BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset,
+ int64_t bytes, BdrvRequestFlags flags,
+ BlockCompletionFunc *cb, void *opaque);
+
+BlockAIOCB *blk_aio_preadv(BlockBackend *blk, int64_t offset,
+ QEMUIOVector *qiov, BdrvRequestFlags flags,
+ BlockCompletionFunc *cb, void *opaque);
+BlockAIOCB *blk_aio_pwritev(BlockBackend *blk, int64_t offset,
+ QEMUIOVector *qiov, BdrvRequestFlags flags,
+ BlockCompletionFunc *cb, void *opaque);
+BlockAIOCB *blk_aio_flush(BlockBackend *blk,
+ BlockCompletionFunc *cb, void *opaque);
+BlockAIOCB *blk_aio_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes,
+ BlockCompletionFunc *cb, void *opaque);
+void blk_aio_cancel(BlockAIOCB *acb);
+void blk_aio_cancel_async(BlockAIOCB *acb);
+int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf);
+BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf,
+ BlockCompletionFunc *cb, void *opaque);
+int coroutine_fn blk_co_pdiscard(BlockBackend *blk, int64_t offset,
+ int64_t bytes);
+int coroutine_fn blk_co_flush(BlockBackend *blk);
+int blk_flush(BlockBackend *blk);
+void blk_inc_in_flight(BlockBackend *blk);
+void blk_dec_in_flight(BlockBackend *blk);
+bool blk_is_inserted(BlockBackend *blk);
+bool blk_is_available(BlockBackend *blk);
+int64_t blk_getlength(BlockBackend *blk);
+void blk_get_geometry(BlockBackend *blk, uint64_t *nb_sectors_ptr);
+void *blk_try_blockalign(BlockBackend *blk, size_t size);
+void *blk_blockalign(BlockBackend *blk, size_t size);
+bool blk_is_writable(BlockBackend *blk);
+BlockdevOnError blk_get_on_error(BlockBackend *blk, bool is_read);
+BlockErrorAction blk_get_error_action(BlockBackend *blk, bool is_read,
+ int error);
+void blk_error_action(BlockBackend *blk, BlockErrorAction action,
+ bool is_read, int error);
+int blk_get_max_iov(BlockBackend *blk);
+int blk_get_max_hw_iov(BlockBackend *blk);
+
+void blk_invalidate_cache(BlockBackend *blk, Error **errp);
+
+void blk_io_plug(BlockBackend *blk);
+void blk_io_unplug(BlockBackend *blk);
+AioContext *blk_get_aio_context(BlockBackend *blk);
+BlockAcctStats *blk_get_stats(BlockBackend *blk);
+void *blk_aio_get(const AIOCBInfo *aiocb_info, BlockBackend *blk,
+ BlockCompletionFunc *cb, void *opaque);
+int blk_pwrite_compressed(BlockBackend *blk, int64_t offset, const void *buf,
+ int64_t bytes);
+int blk_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes);
+int blk_pwrite_zeroes(BlockBackend *blk, int64_t offset,
+ int64_t bytes, BdrvRequestFlags flags);
+int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset,
+ int64_t bytes, BdrvRequestFlags flags);
+int blk_truncate(BlockBackend *blk, int64_t offset, bool exact,
+ PreallocMode prealloc, BdrvRequestFlags flags, Error **errp);
+
+uint32_t blk_get_request_alignment(BlockBackend *blk);
+uint32_t blk_get_max_transfer(BlockBackend *blk);
+uint64_t blk_get_max_hw_transfer(BlockBackend *blk);
+
+int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in,
+ BlockBackend *blk_out, int64_t off_out,
+ int64_t bytes, BdrvRequestFlags read_flags,
+ BdrvRequestFlags write_flags);
+
+
+int blk_make_empty(BlockBackend *blk, Error **errp);
bdrv_make_empty() (called by this function) is classified as a GS
Function, and asserts that it’s running in the main thread. I can also
see that the next patch adds the same assertion to blk_make_empty(), so
I believe this should be a GS function, too.
Hanna
- Re: [PATCH v4 04/25] include/sysemu/block-backend: split header into I/O and global state (GS) API,
Hanna Reitz <=