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vvfat: Use BdrvChild for s->qcow 

vvfat uses a temporary qcow file to cache written data in read-write
mode. In order to do things properly, this should show up in the BDS
graph and I/O should go through BdrvChild like for every other node.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Kevin Wolf 2016-05-30 17:13:09 +02:00
parent a9d52a7563
commit eecc77473b
1 changed files with 43 additions and 23 deletions
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66
block/vvfat.c
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@ -341,9 +341,8 @@ typedef struct BDRVVVFATState {
unsigned int current_cluster;
/* write support */
BlockDriverState* write_target;
char* qcow_filename;
BlockDriverState* qcow;
BdrvChild* qcow;
void* fat2;
char* used_clusters;
array_t commits;
@ -981,7 +980,7 @@ static int init_directories(BDRVVVFATState* s,
static BDRVVVFATState *vvv = NULL;
#endif
static int enable_write_target(BDRVVVFATState *s, Error **errp);
static int enable_write_target(BlockDriverState *bs, Error **errp);
static int is_consistent(BDRVVVFATState *s);
static QemuOptsList runtime_opts = {
@ -1159,7 +1158,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
/* read only is the default for safety */
bs->read_only = true;
s->qcow = s->write_target = NULL;
s->qcow = NULL;
s->qcow_filename = NULL;
s->fat2 = NULL;
s->downcase_short_names = 1;
@ -1170,7 +1169,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
s->sector_count = cyls * heads * secs - (s->first_sectors_number - 1);
if (qemu_opt_get_bool(opts, "rw", false)) {
ret = enable_write_target(s, errp);
ret = enable_write_target(bs, errp);
if (ret < 0) {
goto fail;
}
@ -1391,9 +1390,10 @@ static int vvfat_read(BlockDriverState *bs, int64_t sector_num,
return -1;
if (s->qcow) {
int n;
if (bdrv_is_allocated(s->qcow, sector_num, nb_sectors-i, &n)) {
DLOG(fprintf(stderr, "sectors %d+%d allocated\n", (int)sector_num, n));
if (bdrv_read(s->qcow, sector_num, buf + i*0x200, n)) {
if (bdrv_is_allocated(s->qcow->bs, sector_num, nb_sectors-i, &n)) {
DLOG(fprintf(stderr, "sectors %d+%d allocated\n",
(int)sector_num, n));
if (bdrv_read(s->qcow->bs, sector_num, buf + i * 0x200, n)) {
return -1;
}
i += n - 1;
@ -1669,12 +1669,15 @@ static inline int cluster_was_modified(BDRVVVFATState* s, uint32_t cluster_num)
int was_modified = 0;
int i, dummy;
if (s->qcow == NULL)
return 0;
if (s->qcow == NULL) {
return 0;
}
for (i = 0; !was_modified && i < s->sectors_per_cluster; i++)
was_modified = bdrv_is_allocated(s->qcow,
cluster2sector(s, cluster_num) + i, 1, &dummy);
for (i = 0; !was_modified && i < s->sectors_per_cluster; i++) {
was_modified = bdrv_is_allocated(s->qcow->bs,
cluster2sector(s, cluster_num) + i,
1, &dummy);
}
return was_modified;
}
@ -1823,11 +1826,17 @@ static uint32_t get_cluster_count_for_direntry(BDRVVVFATState* s,
vvfat_close_current_file(s);
for (i = 0; i < s->sectors_per_cluster; i++) {
if (!bdrv_is_allocated(s->qcow, offset + i, 1, &dummy)) {
if (vvfat_read(s->bs, offset, s->cluster_buffer, 1)) {
int res;
res = bdrv_is_allocated(s->qcow->bs, offset + i, 1, &dummy);
if (!res) {
res = vvfat_read(s->bs, offset, s->cluster_buffer, 1);
if (res) {
return -1;
}
if (bdrv_write(s->qcow, offset, s->cluster_buffer, 1)) {
res = bdrv_write(s->qcow->bs, offset,
s->cluster_buffer, 1);
if (res) {
return -2;
}
}
@ -2783,8 +2792,8 @@ static int do_commit(BDRVVVFATState* s)
return ret;
}
if (s->qcow->drv->bdrv_make_empty) {
s->qcow->drv->bdrv_make_empty(s->qcow);
if (s->qcow->bs->drv->bdrv_make_empty) {
s->qcow->bs->drv->bdrv_make_empty(s->qcow->bs);
}
memset(s->used_clusters, 0, sector2cluster(s, s->sector_count));
@ -2880,7 +2889,7 @@ DLOG(checkpoint());
* Use qcow backend. Commit later.
*/
DLOG(fprintf(stderr, "Write to qcow backend: %d + %d\n", (int)sector_num, nb_sectors));
ret = bdrv_write(s->qcow, sector_num, buf, nb_sectors);
ret = bdrv_write(s->qcow->bs, sector_num, buf, nb_sectors);
if (ret < 0) {
fprintf(stderr, "Error writing to qcow backend\n");
return ret;
@ -2950,7 +2959,7 @@ write_target_commit(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
static void write_target_close(BlockDriverState *bs) {
BDRVVVFATState* s = *((BDRVVVFATState**) bs->opaque);
bdrv_unref(s->qcow);
bdrv_unref_child(s->bs, s->qcow);
g_free(s->qcow_filename);
}
@ -2960,8 +2969,19 @@ static BlockDriver vvfat_write_target = {
.bdrv_close = write_target_close,
};
static int enable_write_target(BDRVVVFATState *s, Error **errp)
static void vvfat_qcow_options(int *child_flags, QDict *child_options,
int parent_flags, QDict *parent_options)
{
*child_flags = BDRV_O_RDWR | BDRV_O_NO_FLUSH;
}
static const BdrvChildRole child_vvfat_qcow = {
.inherit_options = vvfat_qcow_options,
};
static int enable_write_target(BlockDriverState *bs, Error **errp)
{
BDRVVVFATState *s = bs->opaque;
BlockDriver *bdrv_qcow = NULL;
BlockDriverState *backing;
QemuOpts *opts = NULL;
@ -3000,8 +3020,8 @@ static int enable_write_target(BDRVVVFATState *s, Error **errp)
options = qdict_new();
qdict_put(options, "driver", qstring_from_str("qcow"));
s->qcow = bdrv_open(s->qcow_filename, NULL, options,
BDRV_O_RDWR | BDRV_O_NO_FLUSH, errp);
s->qcow = bdrv_open_child(s->qcow_filename, options, "write-target", bs,
&child_vvfat_qcow, false, errp);
if (!s->qcow) {
ret = -EINVAL;
goto err;