3d499a43a2
The FUSE export calls blk_exp_ref/unref() without the AioContext lock. Instead of fixing the FUSE export, adjust blk_exp_ref/unref() so they work without the AioContext lock. This way it's less error-prone. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230516190238.8401-15-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
92 lines
2.5 KiB
C
92 lines
2.5 KiB
C
/*
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* Declarations for block exports
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*
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* Copyright (c) 2012, 2020 Red Hat, Inc.
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*
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* Authors:
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* Paolo Bonzini <pbonzini@redhat.com>
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* Kevin Wolf <kwolf@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or
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* later. See the COPYING file in the top-level directory.
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*/
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#ifndef BLOCK_EXPORT_H
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#define BLOCK_EXPORT_H
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#include "qapi/qapi-types-block-export.h"
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#include "qemu/queue.h"
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typedef struct BlockExport BlockExport;
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typedef struct BlockExportDriver {
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/* The export type that this driver services */
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BlockExportType type;
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/*
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* The size of the driver-specific state that contains BlockExport as its
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* first field.
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*/
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size_t instance_size;
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/* Creates and starts a new block export */
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int (*create)(BlockExport *, BlockExportOptions *, Error **);
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/*
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* Frees a removed block export. This function is only called after all
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* references have been dropped.
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*/
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void (*delete)(BlockExport *);
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/*
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* Start to disconnect all clients and drop other references held
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* internally by the export driver. When the function returns, there may
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* still be active references while the export is in the process of
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* shutting down.
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*/
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void (*request_shutdown)(BlockExport *);
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} BlockExportDriver;
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struct BlockExport {
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const BlockExportDriver *drv;
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/* Unique identifier for the export */
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char *id;
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/*
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* Reference count for this block export. This includes strong references
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* both from the owner (qemu-nbd or the monitor) and clients connected to
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* the export.
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*
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* Use atomics to access this field.
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*/
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int refcount;
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/*
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* True if one of the references in refcount belongs to the user. After the
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* user has dropped their reference, they may not e.g. remove the same
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* export a second time (which would decrease the refcount without having
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* it incremented first).
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*/
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bool user_owned;
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/* The AioContext whose lock protects this BlockExport object. */
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AioContext *ctx;
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/* The block device to export */
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BlockBackend *blk;
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/* List entry for block_exports */
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QLIST_ENTRY(BlockExport) next;
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};
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BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp);
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BlockExport *blk_exp_find(const char *id);
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void blk_exp_ref(BlockExport *exp);
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void blk_exp_unref(BlockExport *exp);
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void blk_exp_request_shutdown(BlockExport *exp);
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void blk_exp_close_all(void);
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void blk_exp_close_all_type(BlockExportType type);
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#endif
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