qemu/block/raw-win32.c

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/*
* Block driver for RAW files (win32)
*
* Copyright (c) 2006 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu-common.h"
#include "qemu/timer.h"
#include "block/block_int.h"
#include "qemu/module.h"
#include "raw-aio.h"
#include "trace.h"
#include "block/thread-pool.h"
#include "qemu/iov.h"
#include "qapi/qmp/qstring.h"
#include <windows.h>
#include <winioctl.h>
#define FTYPE_FILE 0
#define FTYPE_CD 1
#define FTYPE_HARDDISK 2
typedef struct RawWin32AIOData {
BlockDriverState *bs;
HANDLE hfile;
struct iovec *aio_iov;
int aio_niov;
size_t aio_nbytes;
off64_t aio_offset;
int aio_type;
} RawWin32AIOData;
typedef struct BDRVRawState {
HANDLE hfile;
int type;
char drive_path[16]; /* format: "d:\" */
QEMUWin32AIOState *aio;
} BDRVRawState;
/*
* Read/writes the data to/from a given linear buffer.
*
* Returns the number of bytes handles or -errno in case of an error. Short
* reads are only returned if the end of the file is reached.
*/
static size_t handle_aiocb_rw(RawWin32AIOData *aiocb)
{
size_t offset = 0;
int i;
for (i = 0; i < aiocb->aio_niov; i++) {
OVERLAPPED ov;
DWORD ret, ret_count, len;
memset(&ov, 0, sizeof(ov));
ov.Offset = (aiocb->aio_offset + offset);
ov.OffsetHigh = (aiocb->aio_offset + offset) >> 32;
len = aiocb->aio_iov[i].iov_len;
if (aiocb->aio_type & QEMU_AIO_WRITE) {
ret = WriteFile(aiocb->hfile, aiocb->aio_iov[i].iov_base,
len, &ret_count, &ov);
} else {
ret = ReadFile(aiocb->hfile, aiocb->aio_iov[i].iov_base,
len, &ret_count, &ov);
}
if (!ret) {
ret_count = 0;
}
if (ret_count != len) {
offset += ret_count;
break;
}
offset += len;
}
return offset;
}
static int aio_worker(void *arg)
{
RawWin32AIOData *aiocb = arg;
ssize_t ret = 0;
size_t count;
switch (aiocb->aio_type & QEMU_AIO_TYPE_MASK) {
case QEMU_AIO_READ:
count = handle_aiocb_rw(aiocb);
if (count < aiocb->aio_nbytes) {
/* A short read means that we have reached EOF. Pad the buffer
* with zeros for bytes after EOF. */
iov_memset(aiocb->aio_iov, aiocb->aio_niov, count,
0, aiocb->aio_nbytes - count);
count = aiocb->aio_nbytes;
}
if (count == aiocb->aio_nbytes) {
ret = 0;
} else {
ret = -EINVAL;
}
break;
case QEMU_AIO_WRITE:
count = handle_aiocb_rw(aiocb);
if (count == aiocb->aio_nbytes) {
ret = 0;
} else {
ret = -EINVAL;
}
break;
case QEMU_AIO_FLUSH:
if (!FlushFileBuffers(aiocb->hfile)) {
return -EIO;
}
break;
default:
fprintf(stderr, "invalid aio request (0x%x)\n", aiocb->aio_type);
ret = -EINVAL;
break;
}
g_slice_free(RawWin32AIOData, aiocb);
return ret;
}
static BlockAIOCB *paio_submit(BlockDriverState *bs, HANDLE hfile,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockCompletionFunc *cb, void *opaque, int type)
{
RawWin32AIOData *acb = g_slice_new(RawWin32AIOData);
ThreadPool *pool;
acb->bs = bs;
acb->hfile = hfile;
acb->aio_type = type;
if (qiov) {
acb->aio_iov = qiov->iov;
acb->aio_niov = qiov->niov;
}
acb->aio_nbytes = nb_sectors * 512;
acb->aio_offset = sector_num * 512;
trace_paio_submit(acb, opaque, sector_num, nb_sectors, type);
pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
return thread_pool_submit_aio(pool, aio_worker, acb, cb, opaque);
}
int qemu_ftruncate64(int fd, int64_t length)
{
LARGE_INTEGER li;
DWORD dw;
LONG high;
HANDLE h;
BOOL res;
if ((GetVersion() & 0x80000000UL) && (length >> 32) != 0)
return -1;
h = (HANDLE)_get_osfhandle(fd);
/* get current position, ftruncate do not change position */
li.HighPart = 0;
li.LowPart = SetFilePointer (h, 0, &li.HighPart, FILE_CURRENT);
if (li.LowPart == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) {
return -1;
}
high = length >> 32;
dw = SetFilePointer(h, (DWORD) length, &high, FILE_BEGIN);
if (dw == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) {
return -1;
}
res = SetEndOfFile(h);
/* back to old position */
SetFilePointer(h, li.LowPart, &li.HighPart, FILE_BEGIN);
return res ? 0 : -1;
}
static int set_sparse(int fd)
{
DWORD returned;
return (int) DeviceIoControl((HANDLE)_get_osfhandle(fd), FSCTL_SET_SPARSE,
NULL, 0, NULL, 0, &returned, NULL);
}
static void raw_detach_aio_context(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
if (s->aio) {
win32_aio_detach_aio_context(s->aio, bdrv_get_aio_context(bs));
}
}
static void raw_attach_aio_context(BlockDriverState *bs,
AioContext *new_context)
{
BDRVRawState *s = bs->opaque;
if (s->aio) {
win32_aio_attach_aio_context(s->aio, new_context);
}
}
static void raw_probe_alignment(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
DWORD sectorsPerCluster, freeClusters, totalClusters, count;
DISK_GEOMETRY_EX dg;
BOOL status;
if (s->type == FTYPE_CD) {
bs->request_alignment = 2048;
return;
}
if (s->type == FTYPE_HARDDISK) {
status = DeviceIoControl(s->hfile, IOCTL_DISK_GET_DRIVE_GEOMETRY_EX,
NULL, 0, &dg, sizeof(dg), &count, NULL);
if (status != 0) {
bs->request_alignment = dg.Geometry.BytesPerSector;
return;
}
/* try GetDiskFreeSpace too */
}
if (s->drive_path[0]) {
GetDiskFreeSpace(s->drive_path, &sectorsPerCluster,
&dg.Geometry.BytesPerSector,
&freeClusters, &totalClusters);
bs->request_alignment = dg.Geometry.BytesPerSector;
}
}
static void raw_parse_flags(int flags, int *access_flags, DWORD *overlapped)
{
assert(access_flags != NULL);
assert(overlapped != NULL);
if (flags & BDRV_O_RDWR) {
*access_flags = GENERIC_READ | GENERIC_WRITE;
} else {
*access_flags = GENERIC_READ;
}
*overlapped = FILE_ATTRIBUTE_NORMAL;
if (flags & BDRV_O_NATIVE_AIO) {
*overlapped |= FILE_FLAG_OVERLAPPED;
}
if (flags & BDRV_O_NOCACHE) {
*overlapped |= FILE_FLAG_NO_BUFFERING;
}
}
static void raw_parse_filename(const char *filename, QDict *options,
Error **errp)
{
/* The filename does not have to be prefixed by the protocol name, since
* "file" is the default protocol; therefore, the return value of this
* function call can be ignored. */
strstart(filename, "file:", &filename);
qdict_put_obj(options, "filename", QOBJECT(qstring_from_str(filename)));
}
static QemuOptsList raw_runtime_opts = {
.name = "raw",
.head = QTAILQ_HEAD_INITIALIZER(raw_runtime_opts.head),
.desc = {
{
.name = "filename",
.type = QEMU_OPT_STRING,
.help = "File name of the image",
},
{ /* end of list */ }
},
};
static int raw_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVRawState *s = bs->opaque;
int access_flags;
DWORD overlapped;
QemuOpts *opts;
Error *local_err = NULL;
const char *filename;
int ret;
s->type = FTYPE_FILE;
opts = qemu_opts_create(&raw_runtime_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
filename = qemu_opt_get(opts, "filename");
raw_parse_flags(flags, &access_flags, &overlapped);
if (filename[0] && filename[1] == ':') {
snprintf(s->drive_path, sizeof(s->drive_path), "%c:\\", filename[0]);
} else if (filename[0] == '\\' && filename[1] == '\\') {
s->drive_path[0] = 0;
} else {
/* Relative path. */
char buf[MAX_PATH];
GetCurrentDirectory(MAX_PATH, buf);
snprintf(s->drive_path, sizeof(s->drive_path), "%c:\\", buf[0]);
}
s->hfile = CreateFile(filename, access_flags,
FILE_SHARE_READ, NULL,
OPEN_EXISTING, overlapped, NULL);
if (s->hfile == INVALID_HANDLE_VALUE) {
int err = GetLastError();
if (err == ERROR_ACCESS_DENIED) {
ret = -EACCES;
} else {
ret = -EINVAL;
}
goto fail;
}
if (flags & BDRV_O_NATIVE_AIO) {
s->aio = win32_aio_init();
if (s->aio == NULL) {
CloseHandle(s->hfile);
error_setg(errp, "Could not initialize AIO");
ret = -EINVAL;
goto fail;
}
ret = win32_aio_attach(s->aio, s->hfile);
if (ret < 0) {
win32_aio_cleanup(s->aio);
CloseHandle(s->hfile);
error_setg_errno(errp, -ret, "Could not enable AIO");
goto fail;
}
win32_aio_attach_aio_context(s->aio, bdrv_get_aio_context(bs));
}
raw_probe_alignment(bs);
ret = 0;
fail:
qemu_opts_del(opts);
return ret;
}
static BlockAIOCB *raw_aio_readv(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockCompletionFunc *cb, void *opaque)
{
BDRVRawState *s = bs->opaque;
if (s->aio) {
return win32_aio_submit(bs, s->aio, s->hfile, sector_num, qiov,
nb_sectors, cb, opaque, QEMU_AIO_READ);
} else {
return paio_submit(bs, s->hfile, sector_num, qiov, nb_sectors,
cb, opaque, QEMU_AIO_READ);
}
}
static BlockAIOCB *raw_aio_writev(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockCompletionFunc *cb, void *opaque)
{
BDRVRawState *s = bs->opaque;
if (s->aio) {
return win32_aio_submit(bs, s->aio, s->hfile, sector_num, qiov,
nb_sectors, cb, opaque, QEMU_AIO_WRITE);
} else {
return paio_submit(bs, s->hfile, sector_num, qiov, nb_sectors,
cb, opaque, QEMU_AIO_WRITE);
}
}
static BlockAIOCB *raw_aio_flush(BlockDriverState *bs,
BlockCompletionFunc *cb, void *opaque)
{
BDRVRawState *s = bs->opaque;
return paio_submit(bs, s->hfile, 0, NULL, 0, cb, opaque, QEMU_AIO_FLUSH);
}
static void raw_close(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
if (s->aio) {
win32_aio_detach_aio_context(s->aio, bdrv_get_aio_context(bs));
win32_aio_cleanup(s->aio);
s->aio = NULL;
}
CloseHandle(s->hfile);
if (bs->open_flags & BDRV_O_TEMPORARY) {
unlink(bs->filename);
}
}
static int raw_truncate(BlockDriverState *bs, int64_t offset)
{
BDRVRawState *s = bs->opaque;
LONG low, high;
DWORD dwPtrLow;
low = offset;
high = offset >> 32;
/*
* An error has occurred if the return value is INVALID_SET_FILE_POINTER
* and GetLastError doesn't return NO_ERROR.
*/
dwPtrLow = SetFilePointer(s->hfile, low, &high, FILE_BEGIN);
if (dwPtrLow == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) {
fprintf(stderr, "SetFilePointer error: %lu\n", GetLastError());
return -EIO;
}
if (SetEndOfFile(s->hfile) == 0) {
fprintf(stderr, "SetEndOfFile error: %lu\n", GetLastError());
return -EIO;
}
return 0;
}
static int64_t raw_getlength(BlockDriverState *bs)
{
BDRVRawState *s = bs->opaque;
LARGE_INTEGER l;
ULARGE_INTEGER available, total, total_free;
DISK_GEOMETRY_EX dg;
DWORD count;
BOOL status;
switch(s->type) {
case FTYPE_FILE:
l.LowPart = GetFileSize(s->hfile, (PDWORD)&l.HighPart);
if (l.LowPart == 0xffffffffUL && GetLastError() != NO_ERROR)
return -EIO;
break;
case FTYPE_CD:
if (!GetDiskFreeSpaceEx(s->drive_path, &available, &total, &total_free))
return -EIO;
l.QuadPart = total.QuadPart;
break;
case FTYPE_HARDDISK:
status = DeviceIoControl(s->hfile, IOCTL_DISK_GET_DRIVE_GEOMETRY_EX,
NULL, 0, &dg, sizeof(dg), &count, NULL);
if (status != 0) {
l = dg.DiskSize;
}
break;
default:
return -EIO;
}
return l.QuadPart;
}
static int64_t raw_get_allocated_file_size(BlockDriverState *bs)
{
typedef DWORD (WINAPI * get_compressed_t)(const char *filename,
DWORD * high);
get_compressed_t get_compressed;
struct _stati64 st;
const char *filename = bs->filename;
/* WinNT support GetCompressedFileSize to determine allocate size */
get_compressed =
(get_compressed_t) GetProcAddress(GetModuleHandle("kernel32"),
"GetCompressedFileSizeA");
if (get_compressed) {
DWORD high, low;
low = get_compressed(filename, &high);
if (low != 0xFFFFFFFFlu || GetLastError() == NO_ERROR) {
return (((int64_t) high) << 32) + low;
}
}
if (_stati64(filename, &st) < 0) {
return -1;
}
return st.st_size;
}
static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
{
int fd;
int64_t total_size = 0;
strstart(filename, "file:", &filename);
/* Read out options */
total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
BDRV_SECTOR_SIZE);
fd = qemu_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
0644);
if (fd < 0) {
error_setg_errno(errp, errno, "Could not create file");
return -EIO;
}
set_sparse(fd);
ftruncate(fd, total_size);
qemu_close(fd);
return 0;
}
static QemuOptsList raw_create_opts = {
.name = "raw-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
.desc = {
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Virtual disk size"
},
{ /* end of list */ }
}
};
BlockDriver bdrv_file = {
block: separate raw images from the file protocol We're running into various problems because the "raw" file access, which is used internally by the various image formats is entangled with the "raw" image format, which maps the VM view 1:1 to a file system. This patch renames the raw file backends to the file protocol which is treated like other protocols (e.g. nbd and http) and adds a new "raw" image format which is just a wrapper around calls to the underlying protocol. The patch is surprisingly simple, besides changing the probing logical in block.c to only look for image formats when using bdrv_open and renaming of the old raw protocols to file there's almost nothing in there. For creating images, a new bdrv_create_file is introduced which guesses the protocol to use. This allows using qemu-img create -f raw (or just using the default) for both files and host devices. Converting the other format drivers to use this function to create their images is left for later patches. The only issues still open are in the handling of the host devices. Firstly in current qemu we can specifiy the host* format names on various command line acceping images, but the new code can't do that without adding some translation. Second the layering breaks the no_zero_init flag in the BlockDriver used by qemu-img. I'm not happy how this is done per-driver instead of per-state so I'll prepare a separate patch to clean this up. There's some more cleanup opportunity after this patch, e.g. using separate lists and registration functions for image formats vs protocols and maybe even host drivers, but this can be done at a later stage. Also there's a check for protocol in bdrv_open for the BDRV_O_SNAPSHOT case that I don't quite understand, but which I fear won't work as expected - possibly even before this patch. Note that this patch requires various recent block patches from Kevin and me, which should all be in his block queue. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-04-08 00:30:24 +04:00
.format_name = "file",
.protocol_name = "file",
.instance_size = sizeof(BDRVRawState),
.bdrv_needs_filename = true,
.bdrv_parse_filename = raw_parse_filename,
.bdrv_file_open = raw_open,
.bdrv_close = raw_close,
.bdrv_create = raw_create,
.bdrv_has_zero_init = bdrv_has_zero_init_1,
.bdrv_aio_readv = raw_aio_readv,
.bdrv_aio_writev = raw_aio_writev,
.bdrv_aio_flush = raw_aio_flush,
.bdrv_truncate = raw_truncate,
.bdrv_getlength = raw_getlength,
.bdrv_get_allocated_file_size
= raw_get_allocated_file_size,
.create_opts = &raw_create_opts,
};
/***********************************************/
/* host device */
static int find_cdrom(char *cdrom_name, int cdrom_name_size)
{
char drives[256], *pdrv = drives;
UINT type;
memset(drives, 0, sizeof(drives));
GetLogicalDriveStrings(sizeof(drives), drives);
while(pdrv[0] != '\0') {
type = GetDriveType(pdrv);
switch(type) {
case DRIVE_CDROM:
snprintf(cdrom_name, cdrom_name_size, "\\\\.\\%c:", pdrv[0]);
return 0;
break;
}
pdrv += lstrlen(pdrv) + 1;
}
return -1;
}
static int find_device_type(BlockDriverState *bs, const char *filename)
{
BDRVRawState *s = bs->opaque;
UINT type;
const char *p;
if (strstart(filename, "\\\\.\\", &p) ||
strstart(filename, "//./", &p)) {
if (stristart(p, "PhysicalDrive", NULL))
return FTYPE_HARDDISK;
snprintf(s->drive_path, sizeof(s->drive_path), "%c:\\", p[0]);
type = GetDriveType(s->drive_path);
switch (type) {
case DRIVE_REMOVABLE:
case DRIVE_FIXED:
return FTYPE_HARDDISK;
case DRIVE_CDROM:
return FTYPE_CD;
default:
return FTYPE_FILE;
}
} else {
return FTYPE_FILE;
}
}
static int hdev_probe_device(const char *filename)
{
if (strstart(filename, "/dev/cdrom", NULL))
return 100;
if (is_windows_drive(filename))
return 100;
return 0;
}
static void hdev_parse_filename(const char *filename, QDict *options,
Error **errp)
{
/* The prefix is optional, just as for "file". */
strstart(filename, "host_device:", &filename);
qdict_put_obj(options, "filename", QOBJECT(qstring_from_str(filename)));
}
static int hdev_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVRawState *s = bs->opaque;
int access_flags, create_flags;
int ret = 0;
DWORD overlapped;
char device_name[64];
Error *local_err = NULL;
const char *filename;
QemuOpts *opts = qemu_opts_create(&raw_runtime_opts, NULL, 0,
&error_abort);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto done;
}
filename = qemu_opt_get(opts, "filename");
if (strstart(filename, "/dev/cdrom", NULL)) {
if (find_cdrom(device_name, sizeof(device_name)) < 0) {
error_setg(errp, "Could not open CD-ROM drive");
ret = -ENOENT;
goto done;
}
filename = device_name;
} else {
/* transform drive letters into device name */
if (((filename[0] >= 'a' && filename[0] <= 'z') ||
(filename[0] >= 'A' && filename[0] <= 'Z')) &&
filename[1] == ':' && filename[2] == '\0') {
snprintf(device_name, sizeof(device_name), "\\\\.\\%c:", filename[0]);
filename = device_name;
}
}
s->type = find_device_type(bs, filename);
raw_parse_flags(flags, &access_flags, &overlapped);
create_flags = OPEN_EXISTING;
s->hfile = CreateFile(filename, access_flags,
FILE_SHARE_READ, NULL,
create_flags, overlapped, NULL);
if (s->hfile == INVALID_HANDLE_VALUE) {
int err = GetLastError();
if (err == ERROR_ACCESS_DENIED) {
ret = -EACCES;
} else {
ret = -EINVAL;
}
error_setg_errno(errp, -ret, "Could not open device");
goto done;
}
done:
qemu_opts_del(opts);
return ret;
}
static BlockDriver bdrv_host_device = {
.format_name = "host_device",
block: separate raw images from the file protocol We're running into various problems because the "raw" file access, which is used internally by the various image formats is entangled with the "raw" image format, which maps the VM view 1:1 to a file system. This patch renames the raw file backends to the file protocol which is treated like other protocols (e.g. nbd and http) and adds a new "raw" image format which is just a wrapper around calls to the underlying protocol. The patch is surprisingly simple, besides changing the probing logical in block.c to only look for image formats when using bdrv_open and renaming of the old raw protocols to file there's almost nothing in there. For creating images, a new bdrv_create_file is introduced which guesses the protocol to use. This allows using qemu-img create -f raw (or just using the default) for both files and host devices. Converting the other format drivers to use this function to create their images is left for later patches. The only issues still open are in the handling of the host devices. Firstly in current qemu we can specifiy the host* format names on various command line acceping images, but the new code can't do that without adding some translation. Second the layering breaks the no_zero_init flag in the BlockDriver used by qemu-img. I'm not happy how this is done per-driver instead of per-state so I'll prepare a separate patch to clean this up. There's some more cleanup opportunity after this patch, e.g. using separate lists and registration functions for image formats vs protocols and maybe even host drivers, but this can be done at a later stage. Also there's a check for protocol in bdrv_open for the BDRV_O_SNAPSHOT case that I don't quite understand, but which I fear won't work as expected - possibly even before this patch. Note that this patch requires various recent block patches from Kevin and me, which should all be in his block queue. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-04-08 00:30:24 +04:00
.protocol_name = "host_device",
.instance_size = sizeof(BDRVRawState),
.bdrv_needs_filename = true,
.bdrv_parse_filename = hdev_parse_filename,
.bdrv_probe_device = hdev_probe_device,
.bdrv_file_open = hdev_open,
.bdrv_close = raw_close,
.bdrv_aio_readv = raw_aio_readv,
.bdrv_aio_writev = raw_aio_writev,
.bdrv_aio_flush = raw_aio_flush,
.bdrv_detach_aio_context = raw_detach_aio_context,
.bdrv_attach_aio_context = raw_attach_aio_context,
2013-10-29 15:18:58 +04:00
.bdrv_getlength = raw_getlength,
.has_variable_length = true,
.bdrv_get_allocated_file_size
= raw_get_allocated_file_size,
};
block: separate raw images from the file protocol We're running into various problems because the "raw" file access, which is used internally by the various image formats is entangled with the "raw" image format, which maps the VM view 1:1 to a file system. This patch renames the raw file backends to the file protocol which is treated like other protocols (e.g. nbd and http) and adds a new "raw" image format which is just a wrapper around calls to the underlying protocol. The patch is surprisingly simple, besides changing the probing logical in block.c to only look for image formats when using bdrv_open and renaming of the old raw protocols to file there's almost nothing in there. For creating images, a new bdrv_create_file is introduced which guesses the protocol to use. This allows using qemu-img create -f raw (or just using the default) for both files and host devices. Converting the other format drivers to use this function to create their images is left for later patches. The only issues still open are in the handling of the host devices. Firstly in current qemu we can specifiy the host* format names on various command line acceping images, but the new code can't do that without adding some translation. Second the layering breaks the no_zero_init flag in the BlockDriver used by qemu-img. I'm not happy how this is done per-driver instead of per-state so I'll prepare a separate patch to clean this up. There's some more cleanup opportunity after this patch, e.g. using separate lists and registration functions for image formats vs protocols and maybe even host drivers, but this can be done at a later stage. Also there's a check for protocol in bdrv_open for the BDRV_O_SNAPSHOT case that I don't quite understand, but which I fear won't work as expected - possibly even before this patch. Note that this patch requires various recent block patches from Kevin and me, which should all be in his block queue. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-04-08 00:30:24 +04:00
static void bdrv_file_init(void)
{
block: separate raw images from the file protocol We're running into various problems because the "raw" file access, which is used internally by the various image formats is entangled with the "raw" image format, which maps the VM view 1:1 to a file system. This patch renames the raw file backends to the file protocol which is treated like other protocols (e.g. nbd and http) and adds a new "raw" image format which is just a wrapper around calls to the underlying protocol. The patch is surprisingly simple, besides changing the probing logical in block.c to only look for image formats when using bdrv_open and renaming of the old raw protocols to file there's almost nothing in there. For creating images, a new bdrv_create_file is introduced which guesses the protocol to use. This allows using qemu-img create -f raw (or just using the default) for both files and host devices. Converting the other format drivers to use this function to create their images is left for later patches. The only issues still open are in the handling of the host devices. Firstly in current qemu we can specifiy the host* format names on various command line acceping images, but the new code can't do that without adding some translation. Second the layering breaks the no_zero_init flag in the BlockDriver used by qemu-img. I'm not happy how this is done per-driver instead of per-state so I'll prepare a separate patch to clean this up. There's some more cleanup opportunity after this patch, e.g. using separate lists and registration functions for image formats vs protocols and maybe even host drivers, but this can be done at a later stage. Also there's a check for protocol in bdrv_open for the BDRV_O_SNAPSHOT case that I don't quite understand, but which I fear won't work as expected - possibly even before this patch. Note that this patch requires various recent block patches from Kevin and me, which should all be in his block queue. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-04-08 00:30:24 +04:00
bdrv_register(&bdrv_file);
bdrv_register(&bdrv_host_device);
}
block: separate raw images from the file protocol We're running into various problems because the "raw" file access, which is used internally by the various image formats is entangled with the "raw" image format, which maps the VM view 1:1 to a file system. This patch renames the raw file backends to the file protocol which is treated like other protocols (e.g. nbd and http) and adds a new "raw" image format which is just a wrapper around calls to the underlying protocol. The patch is surprisingly simple, besides changing the probing logical in block.c to only look for image formats when using bdrv_open and renaming of the old raw protocols to file there's almost nothing in there. For creating images, a new bdrv_create_file is introduced which guesses the protocol to use. This allows using qemu-img create -f raw (or just using the default) for both files and host devices. Converting the other format drivers to use this function to create their images is left for later patches. The only issues still open are in the handling of the host devices. Firstly in current qemu we can specifiy the host* format names on various command line acceping images, but the new code can't do that without adding some translation. Second the layering breaks the no_zero_init flag in the BlockDriver used by qemu-img. I'm not happy how this is done per-driver instead of per-state so I'll prepare a separate patch to clean this up. There's some more cleanup opportunity after this patch, e.g. using separate lists and registration functions for image formats vs protocols and maybe even host drivers, but this can be done at a later stage. Also there's a check for protocol in bdrv_open for the BDRV_O_SNAPSHOT case that I don't quite understand, but which I fear won't work as expected - possibly even before this patch. Note that this patch requires various recent block patches from Kevin and me, which should all be in his block queue. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-04-08 00:30:24 +04:00
block_init(bdrv_file_init);