From: Olga Krishtal <okrish...@virtuozzo.com>
While opening the image we want to be sure that we are the
one who works with image, anf if it is not true -
opening the image for writing should fail.
There are 2 ways at the moment: no lock at all and lock the file
image.
Signed-off-by: Olga Krishtal <okrish...@virtuozzo.com>
Signed-off-by: Denis V. Lunev <d...@openvz.org>
CC: Kevin Wolf <kw...@redhat.com>
CC: Max Reitz <mre...@redhat.com>
CC: Eric Blake <ebl...@redhat.com>
CC: Fam Zheng <f...@redhat.com>
---
block.c | 41 +++++++++++++++++++++++++++++++++++++++++
include/block/block.h | 1 +
include/block/block_int.h | 1 +
qapi/block-core.json | 9 +++++++++
4 files changed, 52 insertions(+)
diff --git a/block.c b/block.c
index 411edbf..74228b8 100644
--- a/block.c
+++ b/block.c
@@ -40,6 +40,8 @@
#include "qemu/timer.h"
#include "qapi-event.h"
#include "block/throttle-groups.h"
+#include "qapi-types.h"
+#include "qapi/util.h"
#ifdef CONFIG_BSD
#include <sys/types.h>
@@ -895,6 +897,12 @@ static QemuOptsList bdrv_runtime_opts = {
.type = QEMU_OPT_BOOL,
.help = "Ignore flush requests",
},
+ {
+ .name = "lock",
+ .type = QEMU_OPT_STRING,
+ .help = "How to lock the image: none or lockfile",
+ .def_value_str = "none",
+ },
{ /* end of list */ }
},
};
@@ -914,6 +922,8 @@ static int bdrv_open_common(BlockDriverState *bs, BdrvChild
*file,
QemuOpts *opts;
BlockDriver *drv;
Error *local_err = NULL;
+ const char *lock_image;
+ int lock;
assert(bs->file == NULL);
assert(options != NULL && bs->options != options);
@@ -1020,6 +1030,18 @@ static int bdrv_open_common(BlockDriverState *bs,
BdrvChild *file,
goto free_and_fail;
}
+ lock_image = qemu_opt_get(opts, "lock");
+ lock = qapi_enum_parse(BdrvLockImage_lookup, lock_image,
+ BDRV_LOCK_IMAGE__MAX, BDRV_LOCK_IMAGE_NONE, &local_err);
+ if (!bs->read_only && lock != BDRV_LOCK_IMAGE_NONE) {
+ ret = bdrv_lock_image(bs, lock);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not lock the image");
+ bdrv_close(bs);
+ goto fail_opts;
+ }
+ }
+
if (bs->encrypted) {
error_report("Encrypted images are deprecated");
error_printf("Support for them will be removed in a future release.\n"
@@ -4320,3 +4342,22 @@ void bdrv_refresh_filename(BlockDriverState *bs)
QDECREF(json);
}
}
+
+int bdrv_lock_image(BlockDriverState *bs, BdrvLockImage lock)
+{
+ BlockDriver *drv = bs->drv;
+ if (lock != BDRV_LOCK_IMAGE_LOCKFILE) {
+ return -EOPNOTSUPP;
+ }
+ if (drv != NULL && drv->bdrv_lock_image != NULL) {
+ return bs->drv->bdrv_lock_image(bs, lock);
+ }
+ if (bs->file == NULL) {
+ return -EOPNOTSUPP;
+ }
+ drv = bs->file->bs->drv;
+ if (drv != NULL && drv->bdrv_lock_image != NULL) {
+ return drv->bdrv_lock_image(bs, lock);
+ }
+ return -EOPNOTSUPP;
+}
diff --git a/include/block/block.h b/include/block/block.h
index db8e096..27fc434 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -506,6 +506,7 @@ void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, struct HBitmapIter *hbi);
void bdrv_set_dirty_iter(struct HBitmapIter *hbi, int64_t offset);
int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
+int bdrv_lock_image(BlockDriverState *bs, BdrvLockImage lock);
void bdrv_enable_copy_on_read(BlockDriverState *bs);
void bdrv_disable_copy_on_read(BlockDriverState *bs);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 256609d..755f342 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -135,6 +135,7 @@ struct BlockDriver {
int (*bdrv_create)(const char *filename, QemuOpts *opts, Error **errp);
int (*bdrv_set_key)(BlockDriverState *bs, const char *key);
int (*bdrv_make_empty)(BlockDriverState *bs);
+ int (*bdrv_lock_image)(BlockDriverState *bs, BdrvLockImage lock);
void (*bdrv_refresh_filename)(BlockDriverState *bs, QDict *options);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 1a5d9ce..b82589b 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2408,3 +2408,12 @@
##
{ 'command': 'block-set-write-threshold',
'data': { 'node-name': 'str', 'write-threshold': 'uint64' } }
+
+##
+# @BdrvLockImage:
+#
+#An enumeration of lock types to lock image file.
+# @none - do not lock the image file
+# @lockfile
+## Since 2.6
+{ 'enum': 'BdrvLockImage', 'data':['none', 'lockfile']}
--
2.1.4
