Merge remote-tracking branch 'remotes/maxreitz/tags/pull-block-2019-10-28' into staging

Block patches for softfreeze:
- iotest patches
- Improve performance of the mirror block job in write-blocking mode
- Limit memory usage for the backup block job
- Add discard and write-zeroes support to the NVMe host block driver
- Fix a bug in the mirror job
- Prevent the qcow2 driver from creating technically non-compliant qcow2
  v3 images (where there is not enough extra data for snapshot table
  entries)
- Allow callers of bdrv_truncate() (etc.) to determine whether the file
  must be resized to the exact given size or whether it is OK for block
  devices not to shrink

# gpg: Signature made Mon 28 Oct 2019 12:13:53 GMT
# gpg:                using RSA key 91BEB60A30DB3E8857D11829F407DB0061D5CF40
# gpg:                issuer "mreitz@redhat.com"
# gpg: Good signature from "Max Reitz <mreitz@redhat.com>" [full]
# Primary key fingerprint: 91BE B60A 30DB 3E88 57D1  1829 F407 DB00 61D5 CF40

* remotes/maxreitz/tags/pull-block-2019-10-28: (69 commits)
  qemu-iotests: restrict 264 to qcow2 only
  Revert "qemu-img: Check post-truncation size"
  block: Pass truncate exact=true where reasonable
  block: Let format drivers pass @exact
  block: Evaluate @exact in protocol drivers
  block: Add @exact parameter to bdrv_co_truncate()
  block: Do not truncate file node when formatting
  block/cor: Drop cor_co_truncate()
  block: Handle filter truncation like native impl.
  iotests: Test qcow2's snapshot table handling
  iotests: Add peek_file* functions
  qcow2: Fix v3 snapshot table entry compliancy
  qcow2: Repair snapshot table with too many entries
  qcow2: Fix overly long snapshot tables
  qcow2: Keep track of the snapshot table length
  qcow2: Fix broken snapshot table entries
  qcow2: Add qcow2_check_fix_snapshot_table()
  qcow2: Separate qcow2_check_read_snapshot_table()
  qcow2: Write v3-compliant snapshot list on upgrade
  qcow2: Put qcow2_upgrade() into its own function
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 17 insertions, 12 deletions

diff --git a/block/io.c b/block/io.c
index e46d9e8b97..02659f994d 100644
--- a/block/io.c
+++ b/block/io.c
@@ -3291,8 +3291,12 @@ static void bdrv_parent_cb_resize(BlockDriverState *bs)
 
 /**
  * Truncate file to 'offset' bytes (needed only for file protocols)
+ *
+ * If 'exact' is true, the file must be resized to exactly the given
+ * 'offset'.  Otherwise, it is sufficient for the node to be at least
+ * 'offset' bytes in length.
  */
-int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset,
+int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
                                   PreallocMode prealloc, Error **errp)
 {
     BlockDriverState *bs = child->bs;
@@ -3347,20 +3351,19 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset,
         goto out;
     }
 
-    if (!drv->bdrv_co_truncate) {
-        if (bs->file && drv->is_filter) {
-            ret = bdrv_co_truncate(bs->file, offset, prealloc, errp);
-            goto out;
-        }
+    if (drv->bdrv_co_truncate) {
+        ret = drv->bdrv_co_truncate(bs, offset, exact, prealloc, errp);
+    } else if (bs->file && drv->is_filter) {
+        ret = bdrv_co_truncate(bs->file, offset, exact, prealloc, errp);
+    } else {
         error_setg(errp, "Image format driver does not support resize");
         ret = -ENOTSUP;
         goto out;
     }
-
-    ret = drv->bdrv_co_truncate(bs, offset, prealloc, errp);
     if (ret < 0) {
         goto out;
     }
+
     ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
     if (ret < 0) {
         error_setg_errno(errp, -ret, "Could not refresh total sector count");
@@ -3382,6 +3385,7 @@ out:
 typedef struct TruncateCo {
     BdrvChild *child;
     int64_t offset;
+    bool exact;
     PreallocMode prealloc;
     Error **errp;
     int ret;
@@ -3390,18 +3394,19 @@ typedef struct TruncateCo {
 static void coroutine_fn bdrv_truncate_co_entry(void *opaque)
 {
     TruncateCo *tco = opaque;
-    tco->ret = bdrv_co_truncate(tco->child, tco->offset, tco->prealloc,
-                                tco->errp);
+    tco->ret = bdrv_co_truncate(tco->child, tco->offset, tco->exact,
+                                tco->prealloc, tco->errp);
     aio_wait_kick();
 }
 
-int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc,
-                  Error **errp)
+int bdrv_truncate(BdrvChild *child, int64_t offset, bool exact,
+                  PreallocMode prealloc, Error **errp)
 {
     Coroutine *co;
     TruncateCo tco = {
         .child      = child,
         .offset     = offset,
+        .exact      = exact,
         .prealloc   = prealloc,
         .errp       = errp,
         .ret        = NOT_DONE,