Truncation is the last to convert from open coded req handling to
reusing helpers. This time the permission check in prepare has to adapt
to the new caller: it checks a different permission bit, and doesn't
trigger the before write notifier.
Also, truncation should always trigger a bs->total_sectors update and in
turn call parent resize_cb. Update the condition in finish helper, too.
It's intended to do a duplicated bs->read_only check before calling
bdrv_co_write_req_prepare() so that we can be more informative with the
error message, as bdrv_co_write_req_prepare() doesn't have Error
parameter.
Signed-off-by: Fam Zheng <f...@redhat.com>
---
block/io.c | 57 ++++++++++++++++++++++++++++++++++--------------------
1 file changed, 36 insertions(+), 21 deletions(-)
diff --git a/block/io.c b/block/io.c
index e3e2d5286d..abcb8b3de6 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1582,14 +1582,24 @@ bdrv_co_write_req_prepare(BdrvChild *child, int64_t
offset, uint64_t bytes,
is_request_serialising_and_aligned(req));
assert(req->overlap_offset <= offset);
assert(offset + bytes <= req->overlap_offset + req->overlap_bytes);
-
- if (flags & BDRV_REQ_WRITE_UNCHANGED) {
- assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE));
- } else {
- assert(child->perm & BLK_PERM_WRITE);
- }
assert(end_sector <= bs->total_sectors || child->perm & BLK_PERM_RESIZE);
- return notifier_with_return_list_notify(&bs->before_write_notifiers, req);
+
+ switch (req->type) {
+ case BDRV_TRACKED_WRITE:
+ case BDRV_TRACKED_DISCARD:
+ if (flags & BDRV_REQ_WRITE_UNCHANGED) {
+ assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE));
+ } else {
+ assert(child->perm & BLK_PERM_WRITE);
+ }
+ return notifier_with_return_list_notify(&bs->before_write_notifiers,
+ req);
+ case BDRV_TRACKED_TRUNCATE:
+ assert(child->perm & BLK_PERM_RESIZE);
+ return 0;
+ default:
+ abort();
+ }
}
static inline void coroutine_fn
@@ -1608,8 +1618,9 @@ bdrv_co_write_req_finish(BdrvChild *child, int64_t
offset, uint64_t bytes,
* beyond EOF cannot expand the image anyway.
* */
if (ret == 0 &&
- end_sector > bs->total_sectors &&
- req->type != BDRV_TRACKED_DISCARD) {
+ (req->type == BDRV_TRACKED_TRUNCATE ||
+ end_sector > bs->total_sectors) &&
+ req->type != BDRV_TRACKED_DISCARD) {
bs->total_sectors = end_sector;
bdrv_parent_cb_resize(bs);
bdrv_dirty_bitmap_truncate(bs, end_sector << BDRV_SECTOR_BITS);
@@ -3088,7 +3099,6 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child,
int64_t offset,
int64_t old_size, new_bytes;
int ret;
- assert(child->perm & BLK_PERM_RESIZE);
/* if bs->drv == NULL, bs is closed, so there's nothing to do here */
if (!drv) {
@@ -3121,7 +3131,18 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child,
int64_t offset,
* concurrently or they might be overwritten by preallocation. */
if (new_bytes) {
mark_request_serialising(&req, 1);
- wait_serialising_requests(&req);
+ }
+ if (bs->read_only) {
+ error_setg(errp, "Image is read-only");
+ ret = -EACCES;
+ goto out;
+ }
+ ret = bdrv_co_write_req_prepare(child, offset - new_bytes, new_bytes, &req,
+ 0);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret,
+ "Failed to prepare request for truncation");
+ goto out;
}
if (!drv->bdrv_co_truncate) {
@@ -3133,13 +3154,6 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child,
int64_t offset,
ret = -ENOTSUP;
goto out;
}
- if (bs->read_only) {
- error_setg(errp, "Image is read-only");
- ret = -EACCES;
- goto out;
- }
-
- assert(!(bs->open_flags & BDRV_O_INACTIVE));
ret = drv->bdrv_co_truncate(bs, offset, prealloc, errp);
if (ret < 0) {
@@ -3151,9 +3165,10 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child,
int64_t offset,
} else {
offset = bs->total_sectors * BDRV_SECTOR_SIZE;
}
- bdrv_dirty_bitmap_truncate(bs, offset);
- bdrv_parent_cb_resize(bs);
- atomic_inc(&bs->write_gen);
+ /* It's possible that truncation succeeded but refresh_total_sectors
+ * failed, but the latter doesn't affect how we should finish the request.
+ * Pass 0 as the last parameter so that dirty bitmaps etc. are handled. */
+ bdrv_co_write_req_finish(child, offset - new_bytes, new_bytes, &req, 0);
out:
tracked_request_end(&req);
--
2.17.1
