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-rw-r--r--block.c148
-rw-r--r--include/block/block.h1
-rwxr-xr-xtests/qemu-iotests/0518
-rw-r--r--tests/qemu-iotests/051.out28
4 files changed, 115 insertions, 70 deletions
diff --git a/block.c b/block.c
index df2b8d1b41..d89c344a13 100644
--- a/block.c
+++ b/block.c
@@ -767,6 +767,11 @@ static int bdrv_open_flags(BlockDriverState *bs, int flags)
{
int open_flags = flags | BDRV_O_CACHE_WB;
+ /* The backing file of a temporary snapshot is read-only */
+ if (flags & BDRV_O_SNAPSHOT) {
+ open_flags &= ~BDRV_O_RDWR;
+ }
+
/*
* Clear flags that are internal to the block layer before opening the
* image.
@@ -1162,6 +1167,68 @@ done:
return ret;
}
+void bdrv_append_temp_snapshot(BlockDriverState *bs, Error **errp)
+{
+ /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
+ char tmp_filename[PATH_MAX + 1];
+
+ int64_t total_size;
+ BlockDriver *bdrv_qcow2;
+ QEMUOptionParameter *create_options;
+ QDict *snapshot_options;
+ BlockDriverState *bs_snapshot;
+ Error *local_err;
+ int ret;
+
+ /* if snapshot, we create a temporary backing file and open it
+ instead of opening 'filename' directly */
+
+ /* Get the required size from the image */
+ total_size = bdrv_getlength(bs) & BDRV_SECTOR_MASK;
+
+ /* Create the temporary image */
+ ret = get_tmp_filename(tmp_filename, sizeof(tmp_filename));
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not get temporary filename");
+ return;
+ }
+
+ bdrv_qcow2 = bdrv_find_format("qcow2");
+ create_options = parse_option_parameters("", bdrv_qcow2->create_options,
+ NULL);
+
+ set_option_parameter_int(create_options, BLOCK_OPT_SIZE, total_size);
+
+ ret = bdrv_create(bdrv_qcow2, tmp_filename, create_options, &local_err);
+ free_option_parameters(create_options);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Could not create temporary overlay "
+ "'%s': %s", tmp_filename,
+ error_get_pretty(local_err));
+ error_free(local_err);
+ return;
+ }
+
+ /* Prepare a new options QDict for the temporary file */
+ snapshot_options = qdict_new();
+ qdict_put(snapshot_options, "file.driver",
+ qstring_from_str("file"));
+ qdict_put(snapshot_options, "file.filename",
+ qstring_from_str(tmp_filename));
+
+ bs_snapshot = bdrv_new("");
+ bs_snapshot->is_temporary = 1;
+
+ ret = bdrv_open(&bs_snapshot, NULL, NULL, snapshot_options,
+ bs->open_flags & ~BDRV_O_SNAPSHOT, bdrv_qcow2, &local_err);
+ if (ret < 0) {
+ error_propagate(errp, local_err);
+ return;
+ }
+
+ bdrv_append(bs_snapshot, bs);
+}
+
/*
* Opens a disk image (raw, qcow2, vmdk, ...)
*
@@ -1182,8 +1249,6 @@ int bdrv_open(BlockDriverState **pbs, const char *filename,
BlockDriver *drv, Error **errp)
{
int ret;
- /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
- char tmp_filename[PATH_MAX + 1];
BlockDriverState *file = NULL, *bs;
const char *drvname;
Error *local_err = NULL;
@@ -1243,74 +1308,6 @@ int bdrv_open(BlockDriverState **pbs, const char *filename,
}
}
- /* For snapshot=on, create a temporary qcow2 overlay */
- if (flags & BDRV_O_SNAPSHOT) {
- BlockDriverState *bs1;
- int64_t total_size;
- BlockDriver *bdrv_qcow2;
- QEMUOptionParameter *create_options;
- QDict *snapshot_options;
-
- /* if snapshot, we create a temporary backing file and open it
- instead of opening 'filename' directly */
-
- /* Get the required size from the image */
- QINCREF(options);
- bs1 = NULL;
- ret = bdrv_open(&bs1, filename, NULL, options, BDRV_O_NO_BACKING,
- drv, &local_err);
- if (ret < 0) {
- goto fail;
- }
- total_size = bdrv_getlength(bs1) & BDRV_SECTOR_MASK;
-
- bdrv_unref(bs1);
-
- /* Create the temporary image */
- ret = get_tmp_filename(tmp_filename, sizeof(tmp_filename));
- if (ret < 0) {
- error_setg_errno(errp, -ret, "Could not get temporary filename");
- goto fail;
- }
-
- bdrv_qcow2 = bdrv_find_format("qcow2");
- create_options = parse_option_parameters("", bdrv_qcow2->create_options,
- NULL);
-
- set_option_parameter_int(create_options, BLOCK_OPT_SIZE, total_size);
-
- ret = bdrv_create(bdrv_qcow2, tmp_filename, create_options, &local_err);
- free_option_parameters(create_options);
- if (ret < 0) {
- error_setg_errno(errp, -ret, "Could not create temporary overlay "
- "'%s': %s", tmp_filename,
- error_get_pretty(local_err));
- error_free(local_err);
- local_err = NULL;
- goto fail;
- }
-
- /* Prepare a new options QDict for the temporary file, where user
- * options refer to the backing file */
- if (filename) {
- qdict_put(options, "file.filename", qstring_from_str(filename));
- }
- if (drv) {
- qdict_put(options, "driver", qstring_from_str(drv->format_name));
- }
-
- snapshot_options = qdict_new();
- qdict_put(snapshot_options, "backing", options);
- qdict_flatten(snapshot_options);
-
- bs->options = snapshot_options;
- options = qdict_clone_shallow(bs->options);
-
- filename = tmp_filename;
- drv = bdrv_qcow2;
- bs->is_temporary = 1;
- }
-
/* Open image file without format layer */
if (flags & BDRV_O_RDWR) {
flags |= BDRV_O_ALLOW_RDWR;
@@ -1372,6 +1369,17 @@ int bdrv_open(BlockDriverState **pbs, const char *filename,
}
}
+ /* For snapshot=on, create a temporary qcow2 overlay. bs points to the
+ * temporary snapshot afterwards. */
+ if (flags & BDRV_O_SNAPSHOT) {
+ bdrv_append_temp_snapshot(bs, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ goto close_and_fail;
+ }
+ }
+
+
done:
/* Check if any unknown options were used */
if (options && (qdict_size(options) != 0)) {
diff --git a/include/block/block.h b/include/block/block.h
index 1ed55d839a..b3230a25f6 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -190,6 +190,7 @@ int bdrv_open_image(BlockDriverState **pbs, const char *filename,
QDict *options, const char *bdref_key, int flags,
bool allow_none, Error **errp);
int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp);
+void bdrv_append_temp_snapshot(BlockDriverState *bs, Error **errp);
int bdrv_open(BlockDriverState **pbs, const char *filename,
const char *reference, QDict *options, int flags,
BlockDriver *drv, Error **errp);
diff --git a/tests/qemu-iotests/051 b/tests/qemu-iotests/051
index 2f79b26076..073dc7a2d3 100755
--- a/tests/qemu-iotests/051
+++ b/tests/qemu-iotests/051
@@ -218,6 +218,14 @@ echo 'qemu-io ide0-hd0 "write -P 0x22 0 4k"' | run_qemu -drive file="$TEST_IMG"
echo 'qemu-io ide0-hd0 "write -P 0x22 0 4k"' | run_qemu -drive file="$TEST_IMG",snapshot=on | _filter_qemu_io
echo 'qemu-io ide0-hd0 "write -P 0x22 0 4k"' | run_qemu -drive file.filename="$TEST_IMG",driver=qcow2,snapshot=on | _filter_qemu_io
echo 'qemu-io ide0-hd0 "write -P 0x22 0 4k"' | run_qemu -drive file.filename="$TEST_IMG",driver=qcow2 -snapshot | _filter_qemu_io
+echo 'qemu-io ide0-hd0 "write -P 0x22 0 4k"' | run_qemu -drive file="file:$TEST_IMG" -snapshot | _filter_qemu_io
+echo 'qemu-io ide0-hd0 "write -P 0x22 0 4k"' | run_qemu -drive file="file:$TEST_IMG",snapshot=on | _filter_qemu_io
+
+# Opening a read-only file r/w with snapshot=on
+chmod u-w "$TEST_IMG"
+echo 'qemu-io ide0-hd0 "write -P 0x22 0 4k"' | run_qemu -drive file="$TEST_IMG" -snapshot | _filter_qemu_io
+echo 'qemu-io ide0-hd0 "write -P 0x22 0 4k"' | run_qemu -drive file="$TEST_IMG",snapshot=on | _filter_qemu_io
+chmod u+w "$TEST_IMG"
$QEMU_IO -c "read -P 0x11 0 4k" "$TEST_IMG" | _filter_qemu_io
diff --git a/tests/qemu-iotests/051.out b/tests/qemu-iotests/051.out
index a631b0b8c4..01b0384472 100644
--- a/tests/qemu-iotests/051.out
+++ b/tests/qemu-iotests/051.out
@@ -319,6 +319,34 @@ wrote 4096/4096 bytes at offset 0
4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
(qemu) qququiquit
+Testing: -drive file=file:TEST_DIR/t.qcow2 -snapshot
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) qqeqemqemuqemu-qemu-iqemu-ioqemu-io qemu-io iqemu-io idqemu-io ideqemu-io ide0qemu-io ide0-qemu-io ide0-hqemu-io ide0-hdqemu-io ide0-hd0qemu-io ide0-hd0 qemu-io ide0-hd0 "qemu-io ide0-hd0 "wqemu-io ide0-hd0 "wrqemu-io ide0-hd0 "wriqemu-io ide0-hd0 "writqemu-io ide0-hd0 "writeqemu-io ide0-hd0 "write qemu-io ide0-hd0 "write -qemu-io ide0-hd0 "write -Pqemu-io ide0-hd0 "write -P qemu-io ide0-hd0 "write -P 0qemu-io ide0-hd0 "write -P 0xqemu-io ide0-hd0 "write -P 0x2qemu-io ide0-hd0 "write -P 0x22qemu-io ide0-hd0 "write -P 0x22 qemu-io ide0-hd0 "write -P 0x22 0qemu-io ide0-hd0 "write -P 0x22 0 qemu-io ide0-hd0 "write -P 0x22 0 4qemu-io ide0-hd0 "write -P 0x22 0 4kqemu-io ide0-hd0 "write -P 0x22 0 4k"
+wrote 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+(qemu) qququiquit
+
+Testing: -drive file=file:TEST_DIR/t.qcow2,snapshot=on
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) qqeqemqemuqemu-qemu-iqemu-ioqemu-io qemu-io iqemu-io idqemu-io ideqemu-io ide0qemu-io ide0-qemu-io ide0-hqemu-io ide0-hdqemu-io ide0-hd0qemu-io ide0-hd0 qemu-io ide0-hd0 "qemu-io ide0-hd0 "wqemu-io ide0-hd0 "wrqemu-io ide0-hd0 "wriqemu-io ide0-hd0 "writqemu-io ide0-hd0 "writeqemu-io ide0-hd0 "write qemu-io ide0-hd0 "write -qemu-io ide0-hd0 "write -Pqemu-io ide0-hd0 "write -P qemu-io ide0-hd0 "write -P 0qemu-io ide0-hd0 "write -P 0xqemu-io ide0-hd0 "write -P 0x2qemu-io ide0-hd0 "write -P 0x22qemu-io ide0-hd0 "write -P 0x22 qemu-io ide0-hd0 "write -P 0x22 0qemu-io ide0-hd0 "write -P 0x22 0 qemu-io ide0-hd0 "write -P 0x22 0 4qemu-io ide0-hd0 "write -P 0x22 0 4kqemu-io ide0-hd0 "write -P 0x22 0 4k"
+wrote 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+(qemu) qququiquit
+
+Testing: -drive file=TEST_DIR/t.qcow2 -snapshot
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) qqeqemqemuqemu-qemu-iqemu-ioqemu-io qemu-io iqemu-io idqemu-io ideqemu-io ide0qemu-io ide0-qemu-io ide0-hqemu-io ide0-hdqemu-io ide0-hd0qemu-io ide0-hd0 qemu-io ide0-hd0 "qemu-io ide0-hd0 "wqemu-io ide0-hd0 "wrqemu-io ide0-hd0 "wriqemu-io ide0-hd0 "writqemu-io ide0-hd0 "writeqemu-io ide0-hd0 "write qemu-io ide0-hd0 "write -qemu-io ide0-hd0 "write -Pqemu-io ide0-hd0 "write -P qemu-io ide0-hd0 "write -P 0qemu-io ide0-hd0 "write -P 0xqemu-io ide0-hd0 "write -P 0x2qemu-io ide0-hd0 "write -P 0x22qemu-io ide0-hd0 "write -P 0x22 qemu-io ide0-hd0 "write -P 0x22 0qemu-io ide0-hd0 "write -P 0x22 0 qemu-io ide0-hd0 "write -P 0x22 0 4qemu-io ide0-hd0 "write -P 0x22 0 4kqemu-io ide0-hd0 "write -P 0x22 0 4k"
+wrote 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+(qemu) qququiquit
+
+Testing: -drive file=TEST_DIR/t.qcow2,snapshot=on
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) qqeqemqemuqemu-qemu-iqemu-ioqemu-io qemu-io iqemu-io idqemu-io ideqemu-io ide0qemu-io ide0-qemu-io ide0-hqemu-io ide0-hdqemu-io ide0-hd0qemu-io ide0-hd0 qemu-io ide0-hd0 "qemu-io ide0-hd0 "wqemu-io ide0-hd0 "wrqemu-io ide0-hd0 "wriqemu-io ide0-hd0 "writqemu-io ide0-hd0 "writeqemu-io ide0-hd0 "write qemu-io ide0-hd0 "write -qemu-io ide0-hd0 "write -Pqemu-io ide0-hd0 "write -P qemu-io ide0-hd0 "write -P 0qemu-io ide0-hd0 "write -P 0xqemu-io ide0-hd0 "write -P 0x2qemu-io ide0-hd0 "write -P 0x22qemu-io ide0-hd0 "write -P 0x22 qemu-io ide0-hd0 "write -P 0x22 0qemu-io ide0-hd0 "write -P 0x22 0 qemu-io ide0-hd0 "write -P 0x22 0 4qemu-io ide0-hd0 "write -P 0x22 0 4kqemu-io ide0-hd0 "write -P 0x22 0 4k"
+wrote 4096/4096 bytes at offset 0
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+(qemu) qququiquit
+
read 4096/4096 bytes at offset 0
4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
Testing: -drive file=TEST_DIR/t.qcow2,snapshot=off