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qcow2: implement bdrv_invalidate_cache (v2) 

We don't reopen the actual file, but instead invoke the close and open routines.
We specifically ignore the backing file since it's contents are read-only and
therefore immutable.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Anthony Liguori 2011-11-14 15:09:46 -06:00
parent 0f15423c32
commit 06d9260ffa
2 changed files with 36 additions and 0 deletions
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34
block/qcow2.c
View File

@ -240,6 +240,7 @@ static int qcow2_open(BlockDriverState *bs, int flags)
s->cluster_data = qemu_blockalign(bs, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
+ 512);
s->cluster_cache_offset = -1;
s->flags = flags;
ret = qcow2_refcount_init(bs);
if (ret != 0) {
@ -632,6 +633,37 @@ static void qcow2_close(BlockDriverState *bs)
qcow2_refcount_close(bs);
}
static void qcow2_invalidate_cache(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
int flags = s->flags;
AES_KEY aes_encrypt_key;
AES_KEY aes_decrypt_key;
uint32_t crypt_method = 0;
/*
* Backing files are read-only which makes all of their metadata immutable,
* that means we don't have to worry about reopening them here.
*/
if (s->crypt_method) {
crypt_method = s->crypt_method;
memcpy(&aes_encrypt_key, &s->aes_encrypt_key, sizeof(aes_encrypt_key));
memcpy(&aes_decrypt_key, &s->aes_decrypt_key, sizeof(aes_decrypt_key));
}
qcow2_close(bs);
memset(s, 0, sizeof(BDRVQcowState));
qcow2_open(bs, flags);
if (crypt_method) {
s->crypt_method = crypt_method;
memcpy(&s->aes_encrypt_key, &aes_encrypt_key, sizeof(aes_encrypt_key));
memcpy(&s->aes_decrypt_key, &aes_decrypt_key, sizeof(aes_decrypt_key));
}
}
/*
* Updates the variable length parts of the qcow2 header, i.e. the backing file
* name and all extensions. qcow2 was not designed to allow such changes, so if
@ -1269,6 +1301,8 @@ static BlockDriver bdrv_qcow2 = {
.bdrv_change_backing_file = qcow2_change_backing_file,
.bdrv_invalidate_cache = qcow2_invalidate_cache,
.create_options = qcow2_create_options,
.bdrv_check = qcow2_check,
};

2
block/qcow2.h
View File

@ -125,6 +125,8 @@ typedef struct BDRVQcowState {
int snapshots_size;
int nb_snapshots;
QCowSnapshot *snapshots;
int flags;
} BDRVQcowState;
/* XXX: use std qcow open function ? */