From: Max Reitz <mreitz@redhat.com>
To: qemu-block@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
qemu-devel@nongnu.org, Max Reitz <mreitz@redhat.com>
Subject: [Qemu-devel] [PATCH v6 15/42] block: Re-evaluate backing file handling in reopen
Date: Fri, 9 Aug 2019 18:13:40 +0200 [thread overview]
Message-ID: <20190809161407.11920-16-mreitz@redhat.com> (raw)
In-Reply-To: <20190809161407.11920-1-mreitz@redhat.com>
Reopening a node's backing child needs a bit of special handling because
the "backing" child has different defaults than all other children
(among other things). Adding filter support here is a bit more
difficult than just using the child access functions. In fact, we often
have to directly use bs->backing because these functions are about the
"backing" child (which may or may not be the COW backing file).
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
block.c | 45 ++++++++++++++++++++++++++++++++++++++-------
1 file changed, 38 insertions(+), 7 deletions(-)
diff --git a/block.c b/block.c
index 42abbaf0ba..064cc99857 100644
--- a/block.c
+++ b/block.c
@@ -3660,25 +3660,56 @@ static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state,
}
}
+ /*
+ * Ensure that @bs can really handle backing files, because we are
+ * about to give it one (or swap the existing one)
+ */
+ if (bs->drv->is_filter) {
+ /* Filters always have a file or a backing child */
+ if (!bs->backing) {
+ error_setg(errp, "'%s' is a %s filter node that does not support a "
+ "backing child", bs->node_name, bs->drv->format_name);
+ return -EINVAL;
+ }
+ } else if (!bs->drv->supports_backing) {
+ error_setg(errp, "Driver '%s' of node '%s' does not support backing "
+ "files", bs->drv->format_name, bs->node_name);
+ return -EINVAL;
+ }
+
/*
* Find the "actual" backing file by skipping all links that point
* to an implicit node, if any (e.g. a commit filter node).
+ * We cannot use any of the bdrv_skip_*() functions here because
+ * those return the first explicit node, while we are looking for
+ * its overlay here.
*/
overlay_bs = bs;
- while (backing_bs(overlay_bs) && backing_bs(overlay_bs)->implicit) {
- overlay_bs = backing_bs(overlay_bs);
+ while (bdrv_filtered_bs(overlay_bs) &&
+ bdrv_filtered_bs(overlay_bs)->implicit)
+ {
+ overlay_bs = bdrv_filtered_bs(overlay_bs);
}
/* If we want to replace the backing file we need some extra checks */
- if (new_backing_bs != backing_bs(overlay_bs)) {
+ if (new_backing_bs != bdrv_filtered_bs(overlay_bs)) {
/* Check for implicit nodes between bs and its backing file */
if (bs != overlay_bs) {
error_setg(errp, "Cannot change backing link if '%s' has "
"an implicit backing file", bs->node_name);
return -EPERM;
}
- /* Check if the backing link that we want to replace is frozen */
- if (bdrv_is_chain_frozen(overlay_bs, backing_bs(overlay_bs), errp)) {
+ /*
+ * Check if the backing link that we want to replace is frozen.
+ * Note that
+ * bdrv_filtered_child(overlay_bs) == overlay_bs->backing,
+ * because we know that overlay_bs == bs, and that @bs
+ * either is an R/W filter that uses ->backing or a COW format
+ * with bs->drv->supports_backing == true.
+ */
+ if (bdrv_is_chain_frozen(overlay_bs, child_bs(overlay_bs->backing),
+ errp))
+ {
return -EPERM;
}
reopen_state->replace_backing_bs = true;
@@ -3829,7 +3860,7 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
* its metadata. Otherwise the 'backing' option can be omitted.
*/
if (drv->supports_backing && reopen_state->backing_missing &&
- (backing_bs(reopen_state->bs) || reopen_state->bs->backing_file[0])) {
+ (reopen_state->bs->backing || reopen_state->bs->backing_file[0])) {
error_setg(errp, "backing is missing for '%s'",
reopen_state->bs->node_name);
ret = -EINVAL;
@@ -3974,7 +4005,7 @@ void bdrv_reopen_commit(BDRVReopenState *reopen_state)
* from bdrv_set_backing_hd()) has the new values.
*/
if (reopen_state->replace_backing_bs) {
- BlockDriverState *old_backing_bs = backing_bs(bs);
+ BlockDriverState *old_backing_bs = child_bs(bs->backing);
assert(!old_backing_bs || !old_backing_bs->implicit);
/* Abort the permission update on the backing bs we're detaching */
if (old_backing_bs) {
--
2.21.0
next prev parent reply other threads:[~2019-08-09 16:18 UTC|newest]
Thread overview: 136+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 16:13 [Qemu-devel] [PATCH v6 00/42] block: Deal with filters Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 01/42] block: Mark commit and mirror as filter drivers Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 02/42] copy-on-read: Support compressed writes Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 03/42] throttle: " Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 04/42] block: Add child access functions Max Reitz
2019-08-09 16:56 ` Eric Blake
2019-09-04 16:16 ` Kevin Wolf
2019-09-09 7:56 ` Max Reitz
2019-09-09 9:36 ` Kevin Wolf
2019-09-09 14:04 ` Max Reitz
2019-09-09 16:13 ` Kevin Wolf
2019-09-10 9:14 ` Max Reitz
2019-09-10 10:47 ` Kevin Wolf
2019-09-10 11:36 ` Max Reitz
2019-09-10 12:48 ` Kevin Wolf
2019-09-10 12:59 ` Max Reitz
2019-09-10 13:10 ` Kevin Wolf
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 05/42] block: Add chain helper functions Max Reitz
2019-08-09 17:01 ` Eric Blake
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 06/42] qcow2: Implement .bdrv_storage_child() Max Reitz
2019-08-09 17:07 ` Eric Blake
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 07/42] block: *filtered_cow_child() for *has_zero_init() Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 08/42] block: bdrv_set_backing_hd() is about bs->backing Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 09/42] block: Include filters when freezing backing chain Max Reitz
2019-08-10 13:32 ` Vladimir Sementsov-Ogievskiy
2019-08-12 12:56 ` Max Reitz
2019-09-05 13:05 ` Kevin Wolf
2019-09-09 8:02 ` Max Reitz
2019-09-09 9:40 ` Kevin Wolf
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 10/42] block: Drop bdrv_is_encrypted() Max Reitz
2019-08-10 13:42 ` Vladimir Sementsov-Ogievskiy
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 11/42] block: Add bdrv_supports_compressed_writes() Max Reitz
2019-09-05 13:11 ` Kevin Wolf
2019-09-09 8:09 ` Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 12/42] block: Use bdrv_filtered_rw* where obvious Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 13/42] block: Use CAFs in block status functions Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 14/42] block: Use CAFs when working with backing chains Max Reitz
2019-08-10 15:19 ` Vladimir Sementsov-Ogievskiy
2019-09-05 14:05 ` Kevin Wolf
2019-09-09 8:25 ` Max Reitz
2019-09-09 9:55 ` Kevin Wolf
2019-09-09 14:08 ` Max Reitz
2019-08-09 16:13 ` Max Reitz [this message]
2019-08-10 16:05 ` [Qemu-devel] [PATCH v6 15/42] block: Re-evaluate backing file handling in reopen Vladimir Sementsov-Ogievskiy
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 16/42] block: Flush all children in generic code Max Reitz
2019-08-10 15:36 ` Vladimir Sementsov-Ogievskiy
2019-08-12 12:58 ` Max Reitz
2019-09-05 16:24 ` Kevin Wolf
2019-09-09 8:31 ` Max Reitz
2019-09-09 10:01 ` Kevin Wolf
2019-09-09 14:15 ` Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 17/42] block: Use CAFs in bdrv_refresh_limits() Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 18/42] block: Use CAFs in bdrv_refresh_filename() Max Reitz
2019-08-10 16:22 ` Vladimir Sementsov-Ogievskiy
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 19/42] block: Use CAF in bdrv_co_rw_vmstate() Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 20/42] block/snapshot: Fix fallback Max Reitz
2019-08-10 16:34 ` Vladimir Sementsov-Ogievskiy
2019-08-12 13:06 ` Max Reitz
2019-09-10 11:56 ` Kevin Wolf
2019-09-10 12:04 ` Max Reitz
2019-09-10 12:49 ` Kevin Wolf
2019-09-10 13:06 ` Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 21/42] block: Use CAFs for debug breakpoints Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 22/42] block: Fix bdrv_get_allocated_file_size's fallback Max Reitz
2019-08-10 16:41 ` Vladimir Sementsov-Ogievskiy
2019-08-12 13:09 ` Max Reitz
2019-08-12 17:14 ` Vladimir Sementsov-Ogievskiy
2019-08-12 19:15 ` Max Reitz
2019-09-10 14:52 ` Kevin Wolf
2019-09-11 6:20 ` Max Reitz
2019-09-11 6:55 ` Kevin Wolf
2019-09-11 7:37 ` Max Reitz
2019-09-11 8:27 ` Kevin Wolf
2019-09-11 10:00 ` Max Reitz
2019-09-11 10:31 ` Kevin Wolf
2019-09-11 11:00 ` Max Reitz
2019-09-12 10:34 ` Kevin Wolf
2019-11-14 13:11 ` Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 23/42] blockdev: Use CAF in external_snapshot_prepare() Max Reitz
2019-09-10 15:02 ` Kevin Wolf
2019-09-11 6:21 ` Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 24/42] block: Use child access functions for QAPI queries Max Reitz
2019-08-10 16:57 ` Vladimir Sementsov-Ogievskiy
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 25/42] mirror: Deal with filters Max Reitz
2019-08-12 11:09 ` Vladimir Sementsov-Ogievskiy
2019-08-12 13:26 ` Max Reitz
2019-08-14 15:17 ` Vladimir Sementsov-Ogievskiy
2019-08-31 9:57 ` Vladimir Sementsov-Ogievskiy
2019-09-02 14:35 ` Max Reitz
2019-09-03 8:32 ` Vladimir Sementsov-Ogievskiy
2019-09-09 7:41 ` Max Reitz
2019-09-13 12:55 ` Kevin Wolf
2019-09-16 10:26 ` Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 26/42] backup: " Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 27/42] commit: " Max Reitz
2019-08-31 10:44 ` Vladimir Sementsov-Ogievskiy
2019-09-02 14:55 ` Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 28/42] stream: " Max Reitz
2019-08-12 11:55 ` Vladimir Sementsov-Ogievskiy
2019-09-13 14:16 ` Kevin Wolf
2019-09-16 9:52 ` Max Reitz
2019-09-16 14:47 ` Kevin Wolf
2019-12-11 12:52 ` Max Reitz
2019-12-11 15:52 ` Kevin Wolf
2019-12-11 16:12 ` Max Reitz
2019-12-11 16:35 ` Kevin Wolf
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 29/42] nbd: Use CAF when looking for dirty bitmap Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 30/42] qemu-img: Use child access functions Max Reitz
2019-08-12 12:14 ` Vladimir Sementsov-Ogievskiy
2019-08-12 13:28 ` Max Reitz
2019-08-14 16:04 ` Vladimir Sementsov-Ogievskiy
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 31/42] block: Drop backing_bs() Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 32/42] block: Make bdrv_get_cumulative_perm() public Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 33/42] blockdev: Fix active commit choice Max Reitz
2019-08-09 16:13 ` [Qemu-devel] [PATCH v6 34/42] block: Inline bdrv_co_block_status_from_*() Max Reitz
2019-08-09 16:14 ` [Qemu-devel] [PATCH v6 35/42] block: Fix check_to_replace_node() Max Reitz
2019-08-15 15:21 ` Vladimir Sementsov-Ogievskiy
2019-08-15 17:01 ` Max Reitz
2019-08-16 11:01 ` Vladimir Sementsov-Ogievskiy
2019-08-16 13:30 ` Max Reitz
2019-08-16 14:24 ` Vladimir Sementsov-Ogievskiy
2019-08-09 16:14 ` [Qemu-devel] [PATCH v6 36/42] iotests: Add tests for mirror @replaces loops Max Reitz
2019-08-09 16:14 ` [Qemu-devel] [PATCH v6 37/42] block: Leave BDS.backing_file constant Max Reitz
2019-08-16 16:16 ` Vladimir Sementsov-Ogievskiy
2019-08-09 16:14 ` [Qemu-devel] [PATCH v6 38/42] iotests: Let complete_and_wait() work with commit Max Reitz
2019-08-23 5:59 ` Vladimir Sementsov-Ogievskiy
2019-08-09 16:14 ` [Qemu-devel] [PATCH v6 39/42] iotests: Add filter commit test cases Max Reitz
2019-08-31 11:41 ` Vladimir Sementsov-Ogievskiy
2019-09-02 15:06 ` Max Reitz
2019-08-31 12:35 ` Vladimir Sementsov-Ogievskiy
2019-09-02 15:09 ` Max Reitz
2019-08-09 16:14 ` [Qemu-devel] [PATCH v6 40/42] iotests: Add filter mirror " Max Reitz
2019-08-31 12:35 ` Vladimir Sementsov-Ogievskiy
2019-08-09 16:14 ` [Qemu-devel] [PATCH v6 41/42] iotests: Add test for commit in sub directory Max Reitz
2019-08-09 16:14 ` [Qemu-devel] [PATCH v6 42/42] iotests: Test committing to overridden backing Max Reitz
2019-09-03 9:18 ` Vladimir Sementsov-Ogievskiy
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