qemu/block/nbd-client.h
Kevin Wolf 5ad81b4946 nbd: Restrict connection_co reentrance
nbd_client_attach_aio_context() schedules connection_co in the new
AioContext and this way reenters it in any arbitrary place that has
yielded. We can restrict this a bit to the function call where the
coroutine actually sits waiting when it's idle.

This doesn't solve any bug yet, but it shows where in the code we need
to support this random reentrance and where we don't have to care.

Add FIXME comments for the existing bugs that the rest of this series
will fix.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2019-02-25 15:03:19 +01:00

73 lines
2.4 KiB
C

#ifndef NBD_CLIENT_H
#define NBD_CLIENT_H
#include "qemu-common.h"
#include "block/nbd.h"
#include "block/block_int.h"
#include "io/channel-socket.h"
/* #define DEBUG_NBD */
#if defined(DEBUG_NBD)
#define logout(fmt, ...) \
fprintf(stderr, "nbd\t%-24s" fmt, __func__, ##__VA_ARGS__)
#else
#define logout(fmt, ...) ((void)0)
#endif
#define MAX_NBD_REQUESTS 16
typedef struct {
Coroutine *coroutine;
uint64_t offset; /* original offset of the request */
bool receiving; /* waiting for connection_co? */
} NBDClientRequest;
typedef struct NBDClientSession {
QIOChannelSocket *sioc; /* The master data channel */
QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */
NBDExportInfo info;
CoMutex send_mutex;
CoQueue free_sema;
Coroutine *connection_co;
int in_flight;
NBDClientRequest requests[MAX_NBD_REQUESTS];
NBDReply reply;
BlockDriverState *bs;
bool quit;
} NBDClientSession;
NBDClientSession *nbd_get_client_session(BlockDriverState *bs);
int nbd_client_init(BlockDriverState *bs,
SocketAddress *saddr,
const char *export_name,
QCryptoTLSCreds *tlscreds,
const char *hostname,
const char *x_dirty_bitmap,
Error **errp);
void nbd_client_close(BlockDriverState *bs);
int nbd_client_co_pdiscard(BlockDriverState *bs, int64_t offset, int bytes);
int nbd_client_co_flush(BlockDriverState *bs);
int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov, int flags);
int nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
int bytes, BdrvRequestFlags flags);
int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov, int flags);
void nbd_client_detach_aio_context(BlockDriverState *bs);
void nbd_client_attach_aio_context(BlockDriverState *bs,
AioContext *new_context);
int coroutine_fn nbd_client_co_block_status(BlockDriverState *bs,
bool want_zero,
int64_t offset, int64_t bytes,
int64_t *pnum, int64_t *map,
BlockDriverState **file);
#endif /* NBD_CLIENT_H */