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qemu/block.h
aliguori baf35cb902 Use signalfd() to work around signal/select race 
This patch introduces signalfd() to work around the signal/select race in
checking for AIO completions.  For platforms that don't support signalfd(), we
emulate it with threads.

There was a long discussion about this approach.  I don't believe there are any
fundamental problems with this approach and I believe eliminating the use of
signals is a good thing.

I've tested Windows and Linux using Windows and Linux guests.  I've also checked
for disk IO performance regressions.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5187 c046a42c-6fe2-441c-8c8c-71466251a162
2008-09-10 15:45:19 +00:00

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#ifndef BLOCK_H
#define BLOCK_H
/* block.c */
typedef struct BlockDriver BlockDriver;
extern BlockDriver bdrv_raw;
extern BlockDriver bdrv_host_device;
extern BlockDriver bdrv_cow;
extern BlockDriver bdrv_qcow;
extern BlockDriver bdrv_vmdk;
extern BlockDriver bdrv_cloop;
extern BlockDriver bdrv_dmg;
extern BlockDriver bdrv_bochs;
extern BlockDriver bdrv_vpc;
extern BlockDriver bdrv_vvfat;
extern BlockDriver bdrv_qcow2;
extern BlockDriver bdrv_parallels;
extern BlockDriver bdrv_nbd;
typedef struct BlockDriverInfo {
/* in bytes, 0 if irrelevant */
int cluster_size;
/* offset at which the VM state can be saved (0 if not possible) */
int64_t vm_state_offset;
} BlockDriverInfo;
typedef struct QEMUSnapshotInfo {
char id_str[128]; /* unique snapshot id */
/* the following fields are informative. They are not needed for
the consistency of the snapshot */
char name[256]; /* user choosen name */
uint32_t vm_state_size; /* VM state info size */
uint32_t date_sec; /* UTC date of the snapshot */
uint32_t date_nsec;
uint64_t vm_clock_nsec; /* VM clock relative to boot */
} QEMUSnapshotInfo;
#define BDRV_O_RDONLY 0x0000
#define BDRV_O_RDWR 0x0002
#define BDRV_O_ACCESS 0x0003
#define BDRV_O_CREAT 0x0004 /* create an empty file */
#define BDRV_O_SNAPSHOT 0x0008 /* open the file read only and save writes in a snapshot */
#define BDRV_O_FILE 0x0010 /* open as a raw file (do not try to
use a disk image format on top of
it (default for
bdrv_file_open()) */
#define BDRV_O_DIRECT 0x0020
#ifndef QEMU_IMG
void bdrv_info(void);
void bdrv_info_stats(void);
#endif
void bdrv_init(void);
BlockDriver *bdrv_find_format(const char *format_name);
int bdrv_create(BlockDriver *drv,
const char *filename, int64_t size_in_sectors,
const char *backing_file, int flags);
BlockDriverState *bdrv_new(const char *device_name);
void bdrv_delete(BlockDriverState *bs);
int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags);
int bdrv_open(BlockDriverState *bs, const char *filename, int flags);
int bdrv_open2(BlockDriverState *bs, const char *filename, int flags,
BlockDriver *drv);
void bdrv_close(BlockDriverState *bs);
int bdrv_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors);
int bdrv_write(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors);
int bdrv_pread(BlockDriverState *bs, int64_t offset,
void *buf, int count);
int bdrv_pwrite(BlockDriverState *bs, int64_t offset,
const void *buf, int count);
int bdrv_truncate(BlockDriverState *bs, int64_t offset);
int64_t bdrv_getlength(BlockDriverState *bs);
void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
int bdrv_commit(BlockDriverState *bs);
void bdrv_set_boot_sector(BlockDriverState *bs, const uint8_t *data, int size);
/* async block I/O */
typedef struct BlockDriverAIOCB BlockDriverAIOCB;
typedef void BlockDriverCompletionFunc(void *opaque, int ret);
BlockDriverAIOCB *bdrv_aio_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque);
BlockDriverAIOCB *bdrv_aio_write(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque);
void bdrv_aio_cancel(BlockDriverAIOCB *acb);
void qemu_aio_init(void);
void qemu_aio_flush(void);
void qemu_aio_wait(void);
int qemu_key_check(BlockDriverState *bs, const char *name);
/* Ensure contents are flushed to disk. */
void bdrv_flush(BlockDriverState *bs);
int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
int *pnum);
#define BDRV_TYPE_HD 0
#define BDRV_TYPE_CDROM 1
#define BDRV_TYPE_FLOPPY 2
#define BIOS_ATA_TRANSLATION_AUTO 0
#define BIOS_ATA_TRANSLATION_NONE 1
#define BIOS_ATA_TRANSLATION_LBA 2
#define BIOS_ATA_TRANSLATION_LARGE 3
#define BIOS_ATA_TRANSLATION_RECHS 4
void bdrv_set_geometry_hint(BlockDriverState *bs,
int cyls, int heads, int secs);
void bdrv_set_type_hint(BlockDriverState *bs, int type);
void bdrv_set_translation_hint(BlockDriverState *bs, int translation);
void bdrv_get_geometry_hint(BlockDriverState *bs,
int *pcyls, int *pheads, int *psecs);
int bdrv_get_type_hint(BlockDriverState *bs);
int bdrv_get_translation_hint(BlockDriverState *bs);
int bdrv_is_removable(BlockDriverState *bs);
int bdrv_is_read_only(BlockDriverState *bs);
int bdrv_is_sg(BlockDriverState *bs);
int bdrv_is_inserted(BlockDriverState *bs);
int bdrv_media_changed(BlockDriverState *bs);
int bdrv_is_locked(BlockDriverState *bs);
void bdrv_set_locked(BlockDriverState *bs, int locked);
void bdrv_eject(BlockDriverState *bs, int eject_flag);
void bdrv_set_change_cb(BlockDriverState *bs,
void (*change_cb)(void *opaque), void *opaque);
void bdrv_get_format(BlockDriverState *bs, char *buf, int buf_size);
BlockDriverState *bdrv_find(const char *name);
void bdrv_iterate(void (*it)(void *opaque, const char *name), void *opaque);
int bdrv_is_encrypted(BlockDriverState *bs);
int bdrv_set_key(BlockDriverState *bs, const char *key);
void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
void *opaque);
const char *bdrv_get_device_name(BlockDriverState *bs);
int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors);
int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
void bdrv_get_backing_filename(BlockDriverState *bs,
char *filename, int filename_size);
int bdrv_snapshot_create(BlockDriverState *bs,
QEMUSnapshotInfo *sn_info);
int bdrv_snapshot_goto(BlockDriverState *bs,
const char *snapshot_id);
int bdrv_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
int bdrv_snapshot_list(BlockDriverState *bs,
QEMUSnapshotInfo **psn_info);
char *bdrv_snapshot_dump(char *buf, int buf_size, QEMUSnapshotInfo *sn);
int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf);
char *get_human_readable_size(char *buf, int buf_size, int64_t size);
int path_is_absolute(const char *path);
void path_combine(char *dest, int dest_size,
const char *base_path,
const char *filename);
#endif
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