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block: Split bdrv_open

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bdrv_open contains quite some code that is only useful for opening images (as
opposed to opening files by a protocol), for example snapshots.

This patch splits the code so that we have bdrv_open_file() for files (uses
protocols), bdrv_open() for images (uses format drivers) and bdrv_open_common()
for the code common for opening both images and files.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2010-04-12 16:37:13 +02:00
parent 84a12e6648
commit b6ce07aa83
1 changed files with 86 additions and 49 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

135
block.c
View File

@ -42,6 +42,9 @@
#include <windows.h>
#endif
static int bdrv_open_common(BlockDriverState *bs, const char *filename,
int flags, BlockDriver *drv);
static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
BlockDriverCompletionFunc *cb, void *opaque);
@ -350,6 +353,9 @@ static BlockDriver *find_image_format(const char *filename)
return drv;
}
/*
* Opens a file using a protocol (file, host_device, nbd, ...)
*/
int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags)
{
BlockDriverState *bs;
@ -362,7 +368,7 @@ int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags)
}
bs = bdrv_new("");
ret = bdrv_open(bs, filename, flags, drv);
ret = bdrv_open_common(bs, filename, flags, drv);
if (ret < 0) {
bdrv_delete(bs);
return ret;
@ -372,19 +378,13 @@ int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags)
return 0;
}
/*
* Opens a disk image (raw, qcow2, vmdk, ...)
*/
int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
BlockDriver *drv)
{
int ret, open_flags;
char tmp_filename[PATH_MAX];
char backing_filename[PATH_MAX];
bs->is_temporary = 0;
bs->encrypted = 0;
bs->valid_key = 0;
bs->open_flags = flags;
/* buffer_alignment defaulted to 512, drivers can change this value */
bs->buffer_alignment = 512;
int ret;
if (flags & BDRV_O_SNAPSHOT) {
BlockDriverState *bs1;
@ -392,6 +392,8 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
int is_protocol = 0;
BlockDriver *bdrv_qcow2;
QEMUOptionParameter *options;
char tmp_filename[PATH_MAX];
char backing_filename[PATH_MAX];
/* if snapshot, we create a temporary backing file and open it
instead of opening 'filename' directly */
@ -439,8 +441,7 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
bs->is_temporary = 1;
}
pstrcpy(bs->filename, sizeof(bs->filename), filename);
/* Find the right image format driver */
if (!drv) {
drv = find_image_format(filename);
}
@ -449,11 +450,81 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
ret = -ENOENT;
goto unlink_and_fail;
}
if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv)) {
ret = -ENOTSUP;
/* Open the image */
ret = bdrv_open_common(bs, filename, flags, drv);
if (ret < 0) {
goto unlink_and_fail;
}
/* If there is a backing file, use it */
if ((flags & BDRV_O_NO_BACKING) == 0 && bs->backing_file[0] != '\0') {
char backing_filename[PATH_MAX];
int back_flags;
BlockDriver *back_drv = NULL;
bs->backing_hd = bdrv_new("");
path_combine(backing_filename, sizeof(backing_filename),
filename, bs->backing_file);
if (bs->backing_format[0] != '\0')
back_drv = bdrv_find_format(bs->backing_format);
/* backing files always opened read-only */
back_flags =
flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
ret = bdrv_open(bs->backing_hd, backing_filename, back_flags, back_drv);
if (ret < 0) {
bdrv_close(bs);
return ret;
}
if (bs->is_temporary) {
bs->backing_hd->keep_read_only = !(flags & BDRV_O_RDWR);
} else {
/* base image inherits from "parent" */
bs->backing_hd->keep_read_only = bs->keep_read_only;
}
}
if (!bdrv_key_required(bs)) {
/* call the change callback */
bs->media_changed = 1;
if (bs->change_cb)
bs->change_cb(bs->change_opaque);
}
return 0;
unlink_and_fail:
if (bs->is_temporary) {
unlink(filename);
}
return ret;
}
/*
* Common part for opening disk images and files
*/
static int bdrv_open_common(BlockDriverState *bs, const char *filename,
int flags, BlockDriver *drv)
{
int ret, open_flags;
assert(drv != NULL);
bs->is_temporary = 0;
bs->encrypted = 0;
bs->valid_key = 0;
bs->open_flags = flags;
/* buffer_alignment defaulted to 512, drivers can change this value */
bs->buffer_alignment = 512;
pstrcpy(bs->filename, sizeof(bs->filename), filename);
if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv)) {
return -ENOTSUP;
}
bs->drv = drv;
bs->opaque = qemu_mallocz(drv->instance_size);
@ -493,46 +564,12 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
unlink(filename);
}
#endif
if ((flags & BDRV_O_NO_BACKING) == 0 && bs->backing_file[0] != '\0') {
/* if there is a backing file, use it */
BlockDriver *back_drv = NULL;
bs->backing_hd = bdrv_new("");
path_combine(backing_filename, sizeof(backing_filename),
filename, bs->backing_file);
if (bs->backing_format[0] != '\0')
back_drv = bdrv_find_format(bs->backing_format);
/* backing files always opened read-only */
open_flags &= ~BDRV_O_RDWR;
ret = bdrv_open(bs->backing_hd, backing_filename, open_flags, back_drv);
if (ret < 0) {
bdrv_close(bs);
return ret;
}
if (bs->is_temporary) {
bs->backing_hd->keep_read_only = !(flags & BDRV_O_RDWR);
} else {
/* base image inherits from "parent" */
bs->backing_hd->keep_read_only = bs->keep_read_only;
}
}
if (!bdrv_key_required(bs)) {
/* call the change callback */
bs->media_changed = 1;
if (bs->change_cb)
bs->change_cb(bs->change_opaque);
}
return 0;
free_and_fail:
qemu_free(bs->opaque);
bs->opaque = NULL;
bs->drv = NULL;
unlink_and_fail:
if (bs->is_temporary)
unlink(filename);
return ret;
}