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Re: [Qemu-devel] [v2 Patch 6/9]block: qcow image file reopen
From: |
Supriya Kannery |
Subject: |
Re: [Qemu-devel] [v2 Patch 6/9]block: qcow image file reopen |
Date: |
Thu, 02 Aug 2012 00:06:58 +0530 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.20) Gecko/20110817 Fedora/3.1.12-1.fc14 Thunderbird/3.1.12 |
qcow driver changes for bdrv_reopen_xx functions to
safely reopen image files. Reopening of image files while
changing hostcache dynamically is handled here.
Signed-off-by: Shrinidhi Joshi <address@hidden>
Index: qemu/block/qcow.c
===================================================================
--- qemu.orig/block/qcow.c
+++ qemu/block/qcow.c
@@ -78,7 +78,14 @@ typedef struct BDRVQcowState {
Error *migration_blocker;
} BDRVQcowState;
+typedef struct BDRVQcowReopenState {
+ BDRVReopenState reopen_state;
+ BDRVQcowState *stash_s;
+} BDRVQcowReopenState;
+
static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
+static void qcow_stash_state(BDRVQcowState *stash_s, BDRVQcowState *s);
+static void qcow_revert_state(BDRVQcowState *s, BDRVQcowState *stash_s);
static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
{
@@ -197,6 +204,103 @@ static int qcow_open(BlockDriverState *b
return ret;
}
+static int qcow_reopen_prepare(BlockDriverState *bs, BDRVReopenState **prs,
+ int flags)
+{
+ BDRVQcowReopenState *qcow_rs = g_malloc0(sizeof(BDRVQcowReopenState));
+ int ret = 0;
+ BDRVQcowState *s = bs->opaque;
+
+ qcow_rs->reopen_state.bs = bs;
+ qcow_rs->stash_s = g_malloc0(sizeof(BDRVQcowState));
+ qcow_stash_state(qcow_rs->stash_s, s);
+ *prs = &(qcow_rs->reopen_state);
+
+ ret = qcow_open(bs, flags);
+ return ret;
+}
+
+static void qcow_reopen_commit(BlockDriverState *bs, BDRVReopenState *rs)
+{
+ BDRVQcowReopenState *qcow_rs;
+
+ qcow_rs = container_of(rs, BDRVQcowReopenState, reopen_state);
+ g_free(qcow_rs->stash_s);
+ g_free(qcow_rs);
+}
+
+static void qcow_reopen_abort(BlockDriverState *bs, BDRVReopenState *rs)
+{
+ BDRVQcowReopenState *qcow_rs;
+ BDRVQcowState *s = bs->opaque;
+
+ qcow_rs = container_of(rs, BDRVQcowReopenState, reopen_state);
+
+ /* revert to stashed state */
+ qcow_revert_state(s, qcow_rs->stash_s);
+
+ g_free(qcow_rs->stash_s);
+ g_free(qcow_rs);
+}
+
+static void qcow_stash_state(BDRVQcowState *stash_s, BDRVQcowState *s)
+{
+ int i;
+
+ stash_s->cluster_bits = s->cluster_bits;
+ stash_s->cluster_size = s->cluster_size;
+ stash_s->cluster_sectors = s->cluster_sectors;
+ stash_s->l2_bits = s->l2_bits;
+ stash_s->l2_size = s->l2_size;
+ stash_s->l1_size = s->l1_size;
+ stash_s->cluster_offset_mask = s->cluster_offset_mask;
+ stash_s->l1_table_offset = s->l1_table_offset;
+ stash_s->l1_table = s->l1_table;
+ stash_s->l2_cache = s->l2_cache;
+ for (i = 0; i < L2_CACHE_SIZE; i++) {
+ stash_s->l2_cache_offsets[i] = s->l2_cache_offsets[i];
+ stash_s->l2_cache_counts[i] = s->l2_cache_counts[i];
+ }
+ stash_s->cluster_cache = s->cluster_cache;
+ stash_s->cluster_data = s->cluster_data;
+ stash_s->cluster_cache_offset = s->cluster_cache_offset;
+ stash_s->crypt_method = s->crypt_method;
+ stash_s->crypt_method_header = s->crypt_method_header;
+ stash_s->aes_encrypt_key = s->aes_encrypt_key;
+ stash_s->aes_decrypt_key = s->aes_decrypt_key;
+ stash_s->lock = s->lock;
+ stash_s->migration_blocker = s->migration_blocker;
+}
+
+static void qcow_revert_state(BDRVQcowState *s, BDRVQcowState *stash_s)
+{
+ int i;
+
+ s->cluster_bits = stash_s->cluster_bits;
+ s->cluster_size = stash_s->cluster_size;
+ s->cluster_sectors = stash_s->cluster_sectors;
+ s->l2_bits = stash_s->l2_bits;
+ s->l2_size = stash_s->l2_size;
+ s->l1_size = stash_s->l1_size;
+ s->cluster_offset_mask = stash_s->cluster_offset_mask;
+ s->l1_table_offset = stash_s->l1_table_offset;
+ s->l1_table = stash_s->l1_table;
+ s->l2_cache = stash_s->l2_cache;
+ for (i = 0; i < L2_CACHE_SIZE; i++) {
+ s->l2_cache_offsets[i] = s->l2_cache_offsets[i];
+ s->l2_cache_counts[i] = stash_s->l2_cache_counts[i];
+ }
+ s->cluster_cache = stash_s->cluster_cache;
+ s->cluster_data = stash_s->cluster_data;
+ s->cluster_cache_offset = stash_s->cluster_cache_offset;
+ s->crypt_method = stash_s->crypt_method;
+ s->crypt_method_header = stash_s->crypt_method_header;
+ s->aes_encrypt_key = stash_s->aes_encrypt_key;
+ s->aes_decrypt_key = stash_s->aes_decrypt_key;
+ s->lock = stash_s->lock;
+ s->migration_blocker = stash_s->migration_blocker;
+}
+
static int qcow_set_key(BlockDriverState *bs, const char *key)
{
BDRVQcowState *s = bs->opaque;
@@ -870,6 +974,10 @@ static BlockDriver bdrv_qcow = {
.bdrv_close = qcow_close,
.bdrv_create = qcow_create,
+ .bdrv_reopen_prepare = qcow_reopen_prepare,
+ .bdrv_reopen_commit = qcow_reopen_commit,
+ .bdrv_reopen_abort = qcow_reopen_abort,
+
.bdrv_co_readv = qcow_co_readv,
.bdrv_co_writev = qcow_co_writev,
.bdrv_co_is_allocated = qcow_co_is_allocated,
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