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authorEric Blake <eblake@redhat.com>2017-03-08 15:34:29 -0600
committerKevin Wolf <kwolf@redhat.com>2017-03-13 12:49:33 +0100
commit7d66b1fbd2112a0c1433ad7106d74c7c39e57f5f (patch)
tree1dec0bf7c29b327a9109adc2611274fa9fd268b9
parent6f712ee08036f4e8066cdddcfed288bf01914e55 (diff)
migration: Document handling of bdrv_is_allocated() errors
Migration is the only code left in the tree that does not react to bdrv_is_allocated() failures. But as there is no useful way to react to the failure, and we are merely skipping unallocated sectors on success, just document that our choice of handling is intended. Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r--migration/block.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/migration/block.c b/migration/block.c
index 1941bc2402..6741228200 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -276,6 +276,8 @@ static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds)
if (bmds->shared_base) {
qemu_mutex_lock_iothread();
aio_context_acquire(blk_get_aio_context(bb));
+ /* Skip unallocated sectors; intentionally treats failure as
+ * an allocated sector */
while (cur_sector < total_sectors &&
!bdrv_is_allocated(blk_bs(bb), cur_sector,
MAX_IS_ALLOCATED_SEARCH, &nr_sectors)) {