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[Qemu-devel] [PATCH v3] block/rbd: increase dynamically the image size
From: |
Stefano Garzarella |
Subject: |
[Qemu-devel] [PATCH v3] block/rbd: increase dynamically the image size |
Date: |
Thu, 9 May 2019 16:59:27 +0200 |
RBD APIs don't allow us to write more than the size set with
rbd_create() or rbd_resize().
In order to support growing images (eg. qcow2), we resize the
image before write operations that exceed the current size.
Signed-off-by: Stefano Garzarella <address@hidden>
---
v3:
- add 'image_size' field in the BDRVRBDState to keep track of the
current size of the RBD image [Jason, Kevin]
---
block/rbd.c | 42 +++++++++++++++++++++++++++++++++++++++---
1 file changed, 39 insertions(+), 3 deletions(-)
diff --git a/block/rbd.c b/block/rbd.c
index 0c549c9935..b0355a2ce0 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -102,6 +102,7 @@ typedef struct BDRVRBDState {
rbd_image_t image;
char *image_name;
char *snap;
+ uint64_t image_size;
} BDRVRBDState;
static int qemu_rbd_connect(rados_t *cluster, rados_ioctx_t *io_ctx,
@@ -777,6 +778,14 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict
*options, int flags,
goto failed_open;
}
+ r = rbd_get_size(s->image, &s->image_size);
+ if (r < 0) {
+ error_setg_errno(errp, -r, "error getting image size from %s",
+ s->image_name);
+ rbd_close(s->image);
+ goto failed_open;
+ }
+
/* If we are using an rbd snapshot, we must be r/o, otherwise
* leave as-is */
if (s->snap != NULL) {
@@ -833,6 +842,22 @@ static void qemu_rbd_close(BlockDriverState *bs)
rados_shutdown(s->cluster);
}
+/* Resize the RBD image and update the 'image_size' with the current size */
+static int qemu_rbd_resize(BlockDriverState *bs, uint64_t size)
+{
+ BDRVRBDState *s = bs->opaque;
+ int r;
+
+ r = rbd_resize(s->image, size);
+ if (r < 0) {
+ return r;
+ }
+
+ s->image_size = size;
+
+ return 0;
+}
+
static const AIOCBInfo rbd_aiocb_info = {
.aiocb_size = sizeof(RBDAIOCB),
};
@@ -934,13 +959,25 @@ static BlockAIOCB *rbd_start_aio(BlockDriverState *bs,
}
switch (cmd) {
- case RBD_AIO_WRITE:
+ case RBD_AIO_WRITE: {
+ /*
+ * RBD APIs don't allow us to write more than actual size, so in order
+ * to support growing images, we resize the image before write
+ * operations that exceed the current size.
+ */
+ if (off + size > s->image_size) {
+ r = qemu_rbd_resize(bs, off + size);
+ if (r < 0) {
+ goto failed_completion;
+ }
+ }
#ifdef LIBRBD_SUPPORTS_IOVEC
r = rbd_aio_writev(s->image, qiov->iov, qiov->niov, off, c);
#else
r = rbd_aio_write(s->image, off, size, rcb->buf, c);
#endif
break;
+ }
case RBD_AIO_READ:
#ifdef LIBRBD_SUPPORTS_IOVEC
r = rbd_aio_readv(s->image, qiov->iov, qiov->niov, off, c);
@@ -1051,7 +1088,6 @@ static int coroutine_fn
qemu_rbd_co_truncate(BlockDriverState *bs,
PreallocMode prealloc,
Error **errp)
{
- BDRVRBDState *s = bs->opaque;
int r;
if (prealloc != PREALLOC_MODE_OFF) {
@@ -1060,7 +1096,7 @@ static int coroutine_fn
qemu_rbd_co_truncate(BlockDriverState *bs,
return -ENOTSUP;
}
- r = rbd_resize(s->image, offset);
+ r = qemu_rbd_resize(bs, offset);
if (r < 0) {
error_setg_errno(errp, -r, "Failed to resize file");
return r;
--
2.20.1
- [Qemu-devel] [PATCH v3] block/rbd: increase dynamically the image size,
Stefano Garzarella <=