From cede621ffc13ba1e209d9a21e85b21e150b74045 Mon Sep 17 00:00:00 2001 From: Liu Yuan Date: Sat, 8 Jun 2013 01:54:26 +0800 Subject: sheepdog: support 'qemu-img snapshot -a' Just call sd_create_branch() in the snapshot_goto to rollback the image is good enough. With this patch, 'loadvm' process for sheepdog is modified: Suppose we have a snapshot chain A --> B --> C, we do 'loadvm A' so as to get a new chain, A --> B | V C1 in the old code: 1 reload inode of A (in snapshot_goto) 2 read vmstate via A's vdi_id (loadvm_state) 3 delete C and create C1, reload inode of C1 (sd_create_branch on write) with this patch applied: 1 reload inode of A, delete C and create C1 (in snapshot_goto) 2 read vmstate via C1's parent, that is A's vdi_id (loadvm_state) This will fix the possible bug that QEMU exit between 2 and 3 in the old code Cc: qemu-devel@nongnu.org Cc: MORITA Kazutaka Cc: Kevin Wolf Cc: Stefan Hajnoczi Signed-off-by: Liu Yuan Signed-off-by: Kevin Wolf --- block/sheepdog.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'block/sheepdog.c') diff --git a/block/sheepdog.c b/block/sheepdog.c index 94218ac937..1b7c3f19b0 100644 --- a/block/sheepdog.c +++ b/block/sheepdog.c @@ -2071,14 +2071,11 @@ static int sd_snapshot_goto(BlockDriverState *bs, const char *snapshot_id) goto out; } - if (!s->inode.vm_state_size) { - error_report("Invalid snapshot"); - ret = -ENOENT; + ret = sd_create_branch(s); + if (ret) { goto out; } - s->is_snapshot = true; - g_free(old_s); return 0; @@ -2196,8 +2193,9 @@ static int do_load_save_vmstate(BDRVSheepdogState *s, uint8_t *data, int fd, ret = 0, remaining = size; unsigned int data_len; uint64_t vmstate_oid; - uint32_t vdi_index; uint64_t offset; + uint32_t vdi_index; + uint32_t vdi_id = load ? s->inode.parent_vdi_id : s->inode.vdi_id; fd = connect_to_sdog(s); if (fd < 0) { @@ -2210,7 +2208,7 @@ static int do_load_save_vmstate(BDRVSheepdogState *s, uint8_t *data, data_len = MIN(remaining, SD_DATA_OBJ_SIZE - offset); - vmstate_oid = vid_to_vmstate_oid(s->inode.vdi_id, vdi_index); + vmstate_oid = vid_to_vmstate_oid(vdi_id, vdi_index); create = (offset == 0); if (load) { -- cgit v1.2.1