On 01/31/2012 09:07 PM, Supriya Kannery wrote:
raw-posix 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: Supriya Kannery<supri...@linux.vnet.ibm.com>
Index: qemu/block/raw.c
===================================================================
--- qemu.orig/block/raw.c
+++ qemu/block/raw.c
@@ -9,6 +9,22 @@ static int raw_open(BlockDriverState *bs
return 0;
}
+static int raw_reopen_prepare(BlockDriverState *bs, BDRVReopenState **prs,
+ int flags)
+{
+ return bdrv_reopen_prepare(bs->file, prs, flags);
+}
+
+static void raw_reopen_commit(BlockDriverState *bs, BDRVReopenState *rs)
+{
+ bdrv_reopen_commit(bs->file, rs);
+}
+
+static void raw_reopen_abort(BlockDriverState *bs, BDRVReopenState *rs)
+{
+ bdrv_reopen_abort(bs->file, rs);
+}
+
static int coroutine_fn raw_co_readv(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
@@ -109,6 +125,10 @@ static BlockDriver bdrv_raw = {
.instance_size = 1,
.bdrv_open = raw_open,
+ .bdrv_reopen_prepare
+ = raw_reopen_prepare,
+ .bdrv_reopen_commit = raw_reopen_commit,
+ .bdrv_reopen_abort = raw_reopen_abort,
.bdrv_close = raw_close,
.bdrv_co_readv = raw_co_readv,
Index: qemu/block/raw-posix.c
===================================================================
--- qemu.orig/block/raw-posix.c
+++ qemu/block/raw-posix.c
@@ -136,6 +136,11 @@ typedef struct BDRVRawState {
#endif
} BDRVRawState;
+typedef struct BDRVRawReopenState {
+ BDRVReopenState reopen_state;
+ BDRVRawState *stash_s;
+} BDRVRawReopenState;
+
static int fd_open(BlockDriverState *bs);
static int64_t raw_getlength(BlockDriverState *bs);
@@ -279,6 +284,71 @@ static int raw_open(BlockDriverState *bs
return raw_open_common(bs, filename, flags, 0);
}
+static int raw_reopen_prepare(BlockDriverState *bs, BDRVReopenState **prs,
+ int flags)
+{
+ BDRVRawReopenState *raw_rs = g_malloc0(sizeof(BDRVRawReopenState));
+ BDRVRawState *s = bs->opaque;
+ int ret = 0;
+
+ raw_rs->reopen_state.bs = bs;
+
+ /* stash state before reopen */
+ raw_rs->stash_s = g_malloc0(sizeof(BDRVRawState));
+ memcpy(raw_rs->stash_s, s, sizeof(BDRVRawState));
+ s->fd = dup(raw_rs->stash_s->fd);
+
+ *prs =&(raw_rs->reopen_state);
+
+ /* Flags that can be set using fcntl */
+ int fcntl_flags = BDRV_O_NOCACHE;
+
+ if ((bs->open_flags& ~fcntl_flags) == (flags& ~fcntl_flags)) {
+ if ((flags& BDRV_O_NOCACHE)) {
+ s->open_flags |= O_DIRECT;
+ } else {
+ s->open_flags&= ~O_DIRECT;
+ }
+ printf("O_DIRECT flag\n");
+ ret = fcntl_setfl(s->fd, s->open_flags);
raw-posix.c:raw_aio_submit() does some extra alignment work if
s->aligned_buf was set due to the image being opened O_DIRECT initially,
not sure what the impact is but probably want to clean that up here.
+ } else {
+
+ printf("close and open with new flags\n");
+ /* close and reopen using new flags */
+ bs->drv->bdrv_close(bs);
+ ret = bs->drv->bdrv_file_open(bs, bs->filename, flags);
+ }
+ return ret;
+}
+
+static void raw_reopen_commit(BlockDriverState *bs, BDRVReopenState *rs)
+{
+ BDRVRawReopenState *raw_rs;
+
+ raw_rs = container_of(rs, BDRVRawReopenState, reopen_state);
+
+ /* clean up stashed state */
+ close(raw_rs->stash_s->fd);
+ g_free(raw_rs->stash_s);
+ g_free(raw_rs);
+}
+
+static void raw_reopen_abort(BlockDriverState *bs, BDRVReopenState *rs)
+{
+ BDRVRawReopenState *raw_rs;
+ BDRVRawState *s = bs->opaque;
+
+ raw_rs = container_of(rs, BDRVRawReopenState, reopen_state);
+
+ /* revert to stashed state */
+ if (s->fd != -1) {
+ close(s->fd);
+ }
+ memcpy(s, raw_rs->stash_s, sizeof(BDRVRawState));
+ g_free(raw_rs->stash_s);
+ g_free(raw_rs);
+}
+
/* XXX: use host sector size if necessary with:
#ifdef DIOCGSECTORSIZE
{
@@ -631,6 +701,9 @@ static BlockDriver bdrv_file = {
.instance_size = sizeof(BDRVRawState),
.bdrv_probe = NULL, /* no probe for protocols */
.bdrv_file_open = raw_open,
+ .bdrv_reopen_prepare = raw_reopen_prepare,
+ .bdrv_reopen_commit = raw_reopen_commit,
+ .bdrv_reopen_abort = raw_reopen_abort,
.bdrv_close = raw_close,
.bdrv_create = raw_create,
.bdrv_co_discard = raw_co_discard,
