[Qemu-devel] [PATCH v4 00/15] Don't pass flags to bdrv_reopen_queue()

[Qemu-devel] [PATCH v4 00/15] Don't pass flags to bdrv_reopen_queue()

[Alberto Garcia]

Hi all,

when reopening a BlockDriverState using bdrv_reopen() and friends the
new options can be specified either with a QDict or with flags. Both
methods overlap and that makes the semantics and the implementation
unnecessarily complicated.

This series removes the 'flags' parameter from these functions, so
from now on all option changes must be specified using a QDict. Apart
from simplifying the API, a few bugs are fixed along the way. See the
individual patches for more details.

This was tested with the current master (4de6bb0c02ad3f0ec48f0f84ba1).

Regards,

Berto

v4:
- Patch 14: Don't assert if BDRV_OPT_AUTO_READ_ONLY is missing, e.g.
  qemu-io -c 'reopen -o auto-read-only=foo' -f raw null-co://

v3: https://lists.gnu.org/archive/html/qemu-block/2018-10/msg00648.html
- Patch 1 [from v2] has been removed and all other patch numbers are
  shifted.
- Patches 10 and 13: Fixed rebase conflicts after the patch removal.
- Patch 14: Replacement for the removed patch using a different approach.
- Patch 15: Document a non-obvious call to update_flags_from_options()

v2: https://lists.gnu.org/archive/html/qemu-block/2018-10/msg00534.html
- Patches 4 and 9: Fixed trivial rebase conflict
- Patch 11: Update messages [Max]
- Patch 12: Add comment and use bdrv_is_read_only() instead of
            using the flags directly [Max]
- Patch 14: Remove inner block and move all variable declarations to
            the beginning of the function [Max]

v1: https://lists.gnu.org/archive/html/qemu-block/2018-09/msg00483.html
- Initial version

Output of backport-diff against v3:

Key:
[----] : patches are identical
[####] : number of functional differences between upstream/downstream patch
[down] : patch is downstream-only
The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively

001/15:[----] [--] 'block: Add bdrv_reopen_set_read_only()'
002/15:[----] [--] 'block: Use bdrv_reopen_set_read_only() in bdrv_backing_update_filename()'
003/15:[----] [--] 'block: Use bdrv_reopen_set_read_only() in commit_start/complete()'
004/15:[----] [--] 'block: Use bdrv_reopen_set_read_only() in bdrv_commit()'
005/15:[----] [--] 'block: Use bdrv_reopen_set_read_only() in stream_start/complete()'
006/15:[----] [--] 'block: Use bdrv_reopen_set_read_only() in qmp_change_backing_file()'
007/15:[----] [--] 'block: Use bdrv_reopen_set_read_only() in external_snapshot_commit()'
008/15:[----] [--] 'block: Use bdrv_reopen_set_read_only() in the mirror driver'
009/15:[----] [--] 'block: Drop bdrv_reopen()'
010/15:[----] [--] 'qemu-io: Put flag changes in the options QDict in reopen_f()'
011/15:[----] [--] 'block: Clean up reopen_backing_file() in block/replication.c'
012/15:[----] [--] 'block: Remove flags parameter from bdrv_reopen_queue()'
013/15:[----] [--] 'block: Stop passing flags to bdrv_reopen_queue_child()'
014/15:[0001] [FC] 'block: Remove assertions from update_flags_from_options()'
015/15:[----] [-C] 'block: Assert that flags are up-to-date in bdrv_reopen_prepare()'

Alberto Garcia (15):
  block: Add bdrv_reopen_set_read_only()
  block: Use bdrv_reopen_set_read_only() in
    bdrv_backing_update_filename()
  block: Use bdrv_reopen_set_read_only() in commit_start/complete()
  block: Use bdrv_reopen_set_read_only() in bdrv_commit()
  block: Use bdrv_reopen_set_read_only() in stream_start/complete()
  block: Use bdrv_reopen_set_read_only() in qmp_change_backing_file()
  block: Use bdrv_reopen_set_read_only() in external_snapshot_commit()
  block: Use bdrv_reopen_set_read_only() in the mirror driver
  block: Drop bdrv_reopen()
  qemu-io: Put flag changes in the options QDict in reopen_f()
  block: Clean up reopen_backing_file() in block/replication.c
  block: Remove flags parameter from bdrv_reopen_queue()
  block: Stop passing flags to bdrv_reopen_queue_child()
  block: Remove assertions from update_flags_from_options()
  block: Assert that flags are up-to-date in bdrv_reopen_prepare()

 block.c                    | 89 ++++++++++++++++++++--------------------------
 block/commit.c             | 23 +++++-------
 block/mirror.c             | 19 ++++++----
 block/replication.c        | 43 ++++++++++------------
 block/stream.c             | 20 +++++------
 blockdev.c                 | 11 ++----
 include/block/block.h      |  6 ++--
 qemu-io-cmds.c             | 29 +++++++++++++--
 tests/qemu-iotests/133     | 17 +++++++++
 tests/qemu-iotests/133.out | 14 ++++++++
 10 files changed, 153 insertions(+), 118 deletions(-)

-- 
2.11.0

[Qemu-devel] [PATCH v4 01/15] block: Add bdrv_reopen_set_read_only()

[Alberto Garcia]

Most callers of bdrv_reopen() only use it to switch a BlockDriverState
between read-only and read-write, so this patch adds a new function
that does just that.

We also want to get rid of the flags parameter in the bdrv_reopen()
API, so this function sets the "read-only" option and passes the
original flags (which will then be updated in bdrv_reopen_prepare()).

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block.c               | 17 +++++++++++++++++
 include/block/block.h |  2 ++
 2 files changed, 19 insertions(+)

diff --git a/block.c b/block.c
index fd67e14dfa..4e82c71ba4 100644
--- a/block.c
+++ b/block.c
@@ -3127,6 +3127,23 @@ int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp)
     return ret;
 }
 
+int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
+                              Error **errp)
+{
+    int ret;
+    BlockReopenQueue *queue;
+    QDict *opts = qdict_new();
+
+    qdict_put_bool(opts, BDRV_OPT_READ_ONLY, read_only);
+
+    bdrv_subtree_drained_begin(bs);
+    queue = bdrv_reopen_queue(NULL, bs, opts, bdrv_get_flags(bs));
+    ret = bdrv_reopen_multiple(bdrv_get_aio_context(bs), queue, errp);
+    bdrv_subtree_drained_end(bs);
+
+    return ret;
+}
+
 static BlockReopenQueueEntry *find_parent_in_reopen_queue(BlockReopenQueue *q,
                                                           BdrvChild *c)
 {
diff --git a/include/block/block.h b/include/block/block.h
index 7f5453b45b..382e6643fc 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -303,6 +303,8 @@ BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
                                     QDict *options, int flags);
 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp);
 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp);
+int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
+                              Error **errp);
 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
                         BlockReopenQueue *queue, Error **errp);
 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
-- 
2.11.0

[Qemu-devel] [PATCH v4 02/15] block: Use bdrv_reopen_set_read_only() in bdrv_backing_update_filename()

[Alberto Garcia]

This patch replaces the bdrv_reopen() calls that set and remove the
BDRV_O_RDWR flag with the new bdrv_reopen_set_read_only() function.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/block.c b/block.c
index 4e82c71ba4..cfa53f7114 100644
--- a/block.c
+++ b/block.c
@@ -1079,11 +1079,11 @@ static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
                                         const char *filename, Error **errp)
 {
     BlockDriverState *parent = c->opaque;
-    int orig_flags = bdrv_get_flags(parent);
+    bool read_only = bdrv_is_read_only(parent);
     int ret;
 
-    if (!(orig_flags & BDRV_O_RDWR)) {
-        ret = bdrv_reopen(parent, orig_flags | BDRV_O_RDWR, errp);
+    if (read_only) {
+        ret = bdrv_reopen_set_read_only(parent, false, errp);
         if (ret < 0) {
             return ret;
         }
@@ -1095,8 +1095,8 @@ static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
         error_setg_errno(errp, -ret, "Could not update backing file link");
     }
 
-    if (!(orig_flags & BDRV_O_RDWR)) {
-        bdrv_reopen(parent, orig_flags, NULL);
+    if (read_only) {
+        bdrv_reopen_set_read_only(parent, true, NULL);
     }
 
     return ret;
-- 
2.11.0

[Qemu-devel] [PATCH v4 03/15] block: Use bdrv_reopen_set_read_only() in commit_start/complete()

[Alberto Garcia]

This patch replaces the bdrv_reopen() calls that set and remove the
BDRV_O_RDWR flag with the new bdrv_reopen_set_read_only() function.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block/commit.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/block/commit.c b/block/commit.c
index a2da5740b0..a53c2d04b0 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -38,7 +38,7 @@ typedef struct CommitBlockJob {
     BlockBackend *base;
     BlockDriverState *base_bs;
     BlockdevOnError on_error;
-    int base_flags;
+    bool base_read_only;
     char *backing_file_str;
 } CommitBlockJob;
 
@@ -124,8 +124,8 @@ static void commit_clean(Job *job)
     /* restore base open flags here if appropriate (e.g., change the base back
      * to r/o). These reopens do not need to be atomic, since we won't abort
      * even on failure here */
-    if (s->base_flags != bdrv_get_flags(s->base_bs)) {
-        bdrv_reopen(s->base_bs, s->base_flags, NULL);
+    if (s->base_read_only) {
+        bdrv_reopen_set_read_only(s->base_bs, true, NULL);
     }
 
     g_free(s->backing_file_str);
@@ -264,7 +264,6 @@ void commit_start(const char *job_id, BlockDriverState *bs,
                   const char *filter_node_name, Error **errp)
 {
     CommitBlockJob *s;
-    int orig_base_flags;
     BlockDriverState *iter;
     BlockDriverState *commit_top_bs = NULL;
     Error *local_err = NULL;
@@ -283,11 +282,9 @@ void commit_start(const char *job_id, BlockDriverState *bs,
     }
 
     /* convert base to r/w, if necessary */
-    orig_base_flags = bdrv_get_flags(base);
-    if (!(orig_base_flags & BDRV_O_RDWR)) {
-        bdrv_reopen(base, orig_base_flags | BDRV_O_RDWR, &local_err);
-        if (local_err != NULL) {
-            error_propagate(errp, local_err);
+    s->base_read_only = bdrv_is_read_only(base);
+    if (s->base_read_only) {
+        if (bdrv_reopen_set_read_only(base, false, errp) != 0) {
             goto fail;
         }
     }
@@ -363,7 +360,6 @@ void commit_start(const char *job_id, BlockDriverState *bs,
         goto fail;
     }
 
-    s->base_flags = orig_base_flags;
     s->backing_file_str = g_strdup(backing_file_str);
     s->on_error = on_error;
 
-- 
2.11.0

[Qemu-devel] [PATCH v4 04/15] block: Use bdrv_reopen_set_read_only() in bdrv_commit()

[Alberto Garcia]

This patch replaces the bdrv_reopen() calls that set and remove the
BDRV_O_RDWR flag with the new bdrv_reopen_set_read_only() function.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block/commit.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/block/commit.c b/block/commit.c
index a53c2d04b0..53148e610b 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -391,7 +391,7 @@ int bdrv_commit(BlockDriverState *bs)
     BlockDriverState *commit_top_bs = NULL;
     BlockDriver *drv = bs->drv;
     int64_t offset, length, backing_length;
-    int ro, open_flags;
+    int ro;
     int64_t n;
     int ret = 0;
     uint8_t *buf = NULL;
@@ -410,10 +410,9 @@ int bdrv_commit(BlockDriverState *bs)
     }
 
     ro = bs->backing->bs->read_only;
-    open_flags =  bs->backing->bs->open_flags;
 
     if (ro) {
-        if (bdrv_reopen(bs->backing->bs, open_flags | BDRV_O_RDWR, NULL)) {
+        if (bdrv_reopen_set_read_only(bs->backing->bs, false, NULL)) {
             return -EACCES;
         }
     }
@@ -523,7 +522,7 @@ ro_cleanup:
 
     if (ro) {
         /* ignoring error return here */
-        bdrv_reopen(bs->backing->bs, open_flags & ~BDRV_O_RDWR, NULL);
+        bdrv_reopen_set_read_only(bs->backing->bs, true, NULL);
     }
 
     return ret;
-- 
2.11.0

[Qemu-devel] [PATCH v4 05/15] block: Use bdrv_reopen_set_read_only() in stream_start/complete()

[Alberto Garcia]

This patch replaces the bdrv_reopen() calls that set and remove the
BDRV_O_RDWR flag with the new bdrv_reopen_set_read_only() function.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block/stream.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/block/stream.c b/block/stream.c
index 81a7ec8ece..262d280ccd 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -34,7 +34,7 @@ typedef struct StreamBlockJob {
     BlockDriverState *base;
     BlockdevOnError on_error;
     char *backing_file_str;
-    int bs_flags;
+    bool bs_read_only;
 } StreamBlockJob;
 
 static int coroutine_fn stream_populate(BlockBackend *blk,
@@ -89,10 +89,10 @@ static void stream_clean(Job *job)
     BlockDriverState *bs = blk_bs(bjob->blk);
 
     /* Reopen the image back in read-only mode if necessary */
-    if (s->bs_flags != bdrv_get_flags(bs)) {
+    if (s->bs_read_only) {
         /* Give up write permissions before making it read-only */
         blk_set_perm(bjob->blk, 0, BLK_PERM_ALL, &error_abort);
-        bdrv_reopen(bs, s->bs_flags, NULL);
+        bdrv_reopen_set_read_only(bs, true, NULL);
     }
 
     g_free(s->backing_file_str);
@@ -226,12 +226,12 @@ void stream_start(const char *job_id, BlockDriverState *bs,
 {
     StreamBlockJob *s;
     BlockDriverState *iter;
-    int orig_bs_flags;
+    int bs_read_only;
 
     /* Make sure that the image is opened in read-write mode */
-    orig_bs_flags = bdrv_get_flags(bs);
-    if (!(orig_bs_flags & BDRV_O_RDWR)) {
-        if (bdrv_reopen(bs, orig_bs_flags | BDRV_O_RDWR, errp) != 0) {
+    bs_read_only = bdrv_is_read_only(bs);
+    if (bs_read_only) {
+        if (bdrv_reopen_set_read_only(bs, false, errp) != 0) {
             return;
         }
     }
@@ -261,7 +261,7 @@ void stream_start(const char *job_id, BlockDriverState *bs,
 
     s->base = base;
     s->backing_file_str = g_strdup(backing_file_str);
-    s->bs_flags = orig_bs_flags;
+    s->bs_read_only = bs_read_only;
 
     s->on_error = on_error;
     trace_stream_start(bs, base, s);
@@ -269,7 +269,7 @@ void stream_start(const char *job_id, BlockDriverState *bs,
     return;
 
 fail:
-    if (orig_bs_flags != bdrv_get_flags(bs)) {
-        bdrv_reopen(bs, orig_bs_flags, NULL);
+    if (bs_read_only) {
+        bdrv_reopen_set_read_only(bs, true, NULL);
     }
 }
-- 
2.11.0

[Qemu-devel] [PATCH v4 06/15] block: Use bdrv_reopen_set_read_only() in qmp_change_backing_file()

[Alberto Garcia]

This patch replaces the bdrv_reopen() calls that set and remove the
BDRV_O_RDWR flag with the new bdrv_reopen_set_read_only() function.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 blockdev.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index e5b5eb46e2..20d1d84bab 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -4100,7 +4100,6 @@ void qmp_change_backing_file(const char *device,
     BlockDriverState *image_bs = NULL;
     Error *local_err = NULL;
     bool ro;
-    int open_flags;
     int ret;
 
     bs = qmp_get_root_bs(device, errp);
@@ -4142,13 +4141,10 @@ void qmp_change_backing_file(const char *device,
     }
 
     /* if not r/w, reopen to make r/w */
-    open_flags = image_bs->open_flags;
     ro = bdrv_is_read_only(image_bs);
 
     if (ro) {
-        bdrv_reopen(image_bs, open_flags | BDRV_O_RDWR, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        if (bdrv_reopen_set_read_only(image_bs, false, errp) != 0) {
             goto out;
         }
     }
@@ -4164,7 +4160,7 @@ void qmp_change_backing_file(const char *device,
     }
 
     if (ro) {
-        bdrv_reopen(image_bs, open_flags, &local_err);
+        bdrv_reopen_set_read_only(image_bs, true, &local_err);
         error_propagate(errp, local_err);
     }
 
-- 
2.11.0

[Qemu-devel] [PATCH v4 07/15] block: Use bdrv_reopen_set_read_only() in external_snapshot_commit()

[Alberto Garcia]

This patch replaces the bdrv_reopen() call that set and remove the
BDRV_O_RDWR flag with the new bdrv_reopen_set_read_only() function.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 blockdev.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 20d1d84bab..112bc62ae5 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1703,8 +1703,7 @@ static void external_snapshot_commit(BlkActionState *common)
      * bdrv_reopen_multiple() across all the entries at once, because we
      * don't want to abort all of them if one of them fails the reopen */
     if (!atomic_read(&state->old_bs->copy_on_read)) {
-        bdrv_reopen(state->old_bs, state->old_bs->open_flags & ~BDRV_O_RDWR,
-                    NULL);
+        bdrv_reopen_set_read_only(state->old_bs, true, NULL);
     }
 
     aio_context_release(aio_context);
-- 
2.11.0

[Qemu-devel] [PATCH v4 08/15] block: Use bdrv_reopen_set_read_only() in the mirror driver

[Alberto Garcia]

The 'block-commit' QMP command is implemented internally using two
different drivers. If the source image is the active layer then the
mirror driver is used (commit_active_start()), otherwise the commit
driver is used (commit_start()).

In both cases the destination image must be put temporarily in
read-write mode. This is done correctly in the latter case, but what
commit_active_start() does is copy all flags instead.

This patch replaces the bdrv_reopen() calls in that function with
bdrv_reopen_set_read_only() so that only the read-only status is
changed.

A similar change is made in mirror_exit(), which is also used by the
'drive-mirror' and 'blockdev-mirror' commands.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block/mirror.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/block/mirror.c b/block/mirror.c
index 56d9ef7474..41b6cbaad6 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -672,9 +672,10 @@ static int mirror_exit_common(Job *job)
 
     if (s->should_complete && !abort) {
         BlockDriverState *to_replace = s->to_replace ?: src;
+        bool ro = bdrv_is_read_only(to_replace);
 
-        if (bdrv_get_flags(target_bs) != bdrv_get_flags(to_replace)) {
-            bdrv_reopen(target_bs, bdrv_get_flags(to_replace), NULL);
+        if (ro != bdrv_is_read_only(target_bs)) {
+            bdrv_reopen_set_read_only(target_bs, ro, NULL);
         }
 
         /* The mirror job has no requests in flight any more, but we need to
@@ -1692,13 +1693,15 @@ void commit_active_start(const char *job_id, BlockDriverState *bs,
                          BlockCompletionFunc *cb, void *opaque,
                          bool auto_complete, Error **errp)
 {
-    int orig_base_flags;
+    bool base_read_only;
     Error *local_err = NULL;
 
-    orig_base_flags = bdrv_get_flags(base);
+    base_read_only = bdrv_is_read_only(base);
 
-    if (bdrv_reopen(base, bs->open_flags, errp)) {
-        return;
+    if (base_read_only) {
+        if (bdrv_reopen_set_read_only(base, false, errp) < 0) {
+            return;
+        }
     }
 
     mirror_start_job(job_id, bs, creation_flags, base, NULL, speed, 0, 0,
@@ -1717,6 +1720,8 @@ void commit_active_start(const char *job_id, BlockDriverState *bs,
 error_restore_flags:
     /* ignore error and errp for bdrv_reopen, because we want to propagate
      * the original error */
-    bdrv_reopen(base, orig_base_flags, NULL);
+    if (base_read_only) {
+        bdrv_reopen_set_read_only(base, true, NULL);
+    }
     return;
 }
-- 
2.11.0

[Qemu-devel] [PATCH v4 09/15] block: Drop bdrv_reopen()

[Alberto Garcia]

No one is using this function anymore, so we can safely remove it.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block.c               | 21 ---------------------
 include/block/block.h |  1 -
 2 files changed, 22 deletions(-)

diff --git a/block.c b/block.c
index cfa53f7114..31de7b2299 100644
--- a/block.c
+++ b/block.c
@@ -3106,27 +3106,6 @@ cleanup:
     return ret;
 }
 
-
-/* Reopen a single BlockDriverState with the specified flags. */
-int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp)
-{
-    int ret = -1;
-    Error *local_err = NULL;
-    BlockReopenQueue *queue;
-
-    bdrv_subtree_drained_begin(bs);
-
-    queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags);
-    ret = bdrv_reopen_multiple(bdrv_get_aio_context(bs), queue, &local_err);
-    if (local_err != NULL) {
-        error_propagate(errp, local_err);
-    }
-
-    bdrv_subtree_drained_end(bs);
-
-    return ret;
-}
-
 int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
                               Error **errp)
 {
diff --git a/include/block/block.h b/include/block/block.h
index 382e6643fc..de72c7a093 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -302,7 +302,6 @@ BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
                                     BlockDriverState *bs,
                                     QDict *options, int flags);
 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp);
-int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp);
 int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
                               Error **errp);
 int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
-- 
2.11.0

[Qemu-devel] [PATCH v4 10/15] qemu-io: Put flag changes in the options QDict in reopen_f()

[Alberto Garcia]

When reopen_f() puts a block device in the reopen queue, some of the
new options are passed using a QDict, but others ("read-only" and the
cache options) are passed as flags.

This patch puts those flags in the QDict. This way the flags parameter
becomes redundant and we'll be able to get rid of it in a subsequent
patch.

Signed-off-by: Alberto Garcia <berto@igalia.com>
---
 qemu-io-cmds.c             | 27 ++++++++++++++++++++++++++-
 tests/qemu-iotests/133     |  9 +++++++++
 tests/qemu-iotests/133.out |  8 ++++++++
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index 5363482213..c9ae09d574 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -10,6 +10,7 @@
 
 #include "qemu/osdep.h"
 #include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
 #include "qemu-io.h"
 #include "sysemu/block-backend.h"
 #include "block/block.h"
@@ -1978,6 +1979,7 @@ static int reopen_f(BlockBackend *blk, int argc, char **argv)
     int flags = bs->open_flags;
     bool writethrough = !blk_enable_write_cache(blk);
     bool has_rw_option = false;
+    bool has_cache_option = false;
 
     BlockReopenQueue *brq;
     Error *local_err = NULL;
@@ -1989,6 +1991,7 @@ static int reopen_f(BlockBackend *blk, int argc, char **argv)
                 error_report("Invalid cache option: %s", optarg);
                 return -EINVAL;
             }
+            has_cache_option = true;
             break;
         case 'o':
             if (!qemu_opts_parse_noisily(&reopen_opts, optarg, 0)) {
@@ -2046,9 +2049,31 @@ static int reopen_f(BlockBackend *blk, int argc, char **argv)
     }
 
     qopts = qemu_opts_find(&reopen_opts, NULL);
-    opts = qopts ? qemu_opts_to_qdict(qopts, NULL) : NULL;
+    opts = qopts ? qemu_opts_to_qdict(qopts, NULL) : qdict_new();
     qemu_opts_reset(&reopen_opts);
 
+    if (qdict_haskey(opts, BDRV_OPT_READ_ONLY)) {
+        if (has_rw_option) {
+            error_report("Cannot set both -r/-w and '" BDRV_OPT_READ_ONLY "'");
+            qobject_unref(opts);
+            return -EINVAL;
+        }
+    } else {
+        qdict_put_bool(opts, BDRV_OPT_READ_ONLY, !(flags & BDRV_O_RDWR));
+    }
+
+    if (qdict_haskey(opts, BDRV_OPT_CACHE_DIRECT) ||
+        qdict_haskey(opts, BDRV_OPT_CACHE_NO_FLUSH)) {
+        if (has_cache_option) {
+            error_report("Cannot set both -c and the cache options");
+            qobject_unref(opts);
+            return -EINVAL;
+        }
+    } else {
+        qdict_put_bool(opts, BDRV_OPT_CACHE_DIRECT, flags & BDRV_O_NOCACHE);
+        qdict_put_bool(opts, BDRV_OPT_CACHE_NO_FLUSH, flags & BDRV_O_NO_FLUSH);
+    }
+
     bdrv_subtree_drained_begin(bs);
     brq = bdrv_reopen_queue(NULL, bs, opts, flags);
     bdrv_reopen_multiple(bdrv_get_aio_context(bs), brq, &local_err);
diff --git a/tests/qemu-iotests/133 b/tests/qemu-iotests/133
index af6b3e1dd4..14e6b3b972 100755
--- a/tests/qemu-iotests/133
+++ b/tests/qemu-iotests/133
@@ -92,6 +92,15 @@ echo
 IMGOPTSSYNTAX=false $QEMU_IO -f null-co -c 'reopen' -c 'info' \
     "json:{'driver': 'null-co', 'size': 65536}"
 
+echo
+echo "=== Check that mixing -c/-r/-w and their corresponding options is forbidden ==="
+echo
+
+$QEMU_IO -c 'reopen -r -o read-only=on' $TEST_IMG
+$QEMU_IO -c 'reopen -w -o read-only=on' $TEST_IMG
+$QEMU_IO -c 'reopen -c none -o cache.direct=on' $TEST_IMG
+$QEMU_IO -c 'reopen -c writeback -o cache.direct=on' $TEST_IMG
+$QEMU_IO -c 'reopen -c directsync -o cache.no-flush=on' $TEST_IMG
 # success, all done
 echo "*** done"
 rm -f $seq.full
diff --git a/tests/qemu-iotests/133.out b/tests/qemu-iotests/133.out
index f4a85aeb63..48a9d087f0 100644
--- a/tests/qemu-iotests/133.out
+++ b/tests/qemu-iotests/133.out
@@ -24,4 +24,12 @@ Cannot change the option 'driver'
 
 format name: null-co
 format name: null-co
+
+=== Check that mixing -c/-r/-w and their corresponding options is forbidden ===
+
+Cannot set both -r/-w and 'read-only'
+Cannot set both -r/-w and 'read-only'
+Cannot set both -c and the cache options
+Cannot set both -c and the cache options
+Cannot set both -c and the cache options
 *** done
-- 
2.11.0

Re: [Qemu-devel] [PATCH v4 10/15] qemu-io: Put flag changes in the options QDict in reopen_f()

[Max Reitz]

[-- Attachment #1: Type: text/plain, Size: 705 bytes --]

On 07.11.18 13:59, Alberto Garcia wrote:
> When reopen_f() puts a block device in the reopen queue, some of the
> new options are passed using a QDict, but others ("read-only" and the
> cache options) are passed as flags.
> 
> This patch puts those flags in the QDict. This way the flags parameter
> becomes redundant and we'll be able to get rid of it in a subsequent
> patch.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>  qemu-io-cmds.c             | 27 ++++++++++++++++++++++++++-
>  tests/qemu-iotests/133     |  9 +++++++++
>  tests/qemu-iotests/133.out |  8 ++++++++
>  3 files changed, 43 insertions(+), 1 deletion(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>


[-- Attachment #2: OpenPGP digital signature --]
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[Qemu-devel] [PATCH v4 11/15] block: Clean up reopen_backing_file() in block/replication.c

[Alberto Garcia]

This function is used to put the hidden and secondary disks in
read-write mode before launching the backup job, and back in read-only
mode afterwards.

This patch does the following changes:

  - Use an options QDict with the "read-only" option instead of
    passing the changes as flags only.

  - Simplify the code (it was unnecessarily complicated and verbose).

  - Fix a bug due to which the secondary disk was not being put back
    in read-only mode when writable=false (because in this case
    orig_secondary_flags always had the BDRV_O_RDWR flag set).

  - Stop clearing the BDRV_O_INACTIVE flag.

The flags parameter to bdrv_reopen_queue() becomes redundant and we'll
be able to get rid of it in a subsequent patch.

Signed-off-by: Alberto Garcia <berto@igalia.com>
---
 block/replication.c | 45 +++++++++++++++++++++------------------------
 1 file changed, 21 insertions(+), 24 deletions(-)

diff --git a/block/replication.c b/block/replication.c
index 6349d6958e..481a225924 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -20,6 +20,7 @@
 #include "block/block_backup.h"
 #include "sysemu/block-backend.h"
 #include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
 #include "replication.h"
 
 typedef enum {
@@ -39,8 +40,8 @@ typedef struct BDRVReplicationState {
     char *top_id;
     ReplicationState *rs;
     Error *blocker;
-    int orig_hidden_flags;
-    int orig_secondary_flags;
+    bool orig_hidden_read_only;
+    bool orig_secondary_read_only;
     int error;
 } BDRVReplicationState;
 
@@ -371,44 +372,40 @@ static void secondary_do_checkpoint(BDRVReplicationState *s, Error **errp)
     }
 }
 
+/* This function is supposed to be called twice:
+ * first with writable = true, then with writable = false.
+ * The first call puts s->hidden_disk and s->secondary_disk in
+ * r/w mode, and the second puts them back in their original state.
+ */
 static void reopen_backing_file(BlockDriverState *bs, bool writable,
                                 Error **errp)
 {
     BDRVReplicationState *s = bs->opaque;
     BlockReopenQueue *reopen_queue = NULL;
-    int orig_hidden_flags, orig_secondary_flags;
-    int new_hidden_flags, new_secondary_flags;
     Error *local_err = NULL;
 
     if (writable) {
-        orig_hidden_flags = s->orig_hidden_flags =
-                                bdrv_get_flags(s->hidden_disk->bs);
-        new_hidden_flags = (orig_hidden_flags | BDRV_O_RDWR) &
-                                                    ~BDRV_O_INACTIVE;
-        orig_secondary_flags = s->orig_secondary_flags =
-                                bdrv_get_flags(s->secondary_disk->bs);
-        new_secondary_flags = (orig_secondary_flags | BDRV_O_RDWR) &
-                                                     ~BDRV_O_INACTIVE;
-    } else {
-        orig_hidden_flags = (s->orig_hidden_flags | BDRV_O_RDWR) &
-                                                    ~BDRV_O_INACTIVE;
-        new_hidden_flags = s->orig_hidden_flags;
-        orig_secondary_flags = (s->orig_secondary_flags | BDRV_O_RDWR) &
-                                                    ~BDRV_O_INACTIVE;
-        new_secondary_flags = s->orig_secondary_flags;
+        s->orig_hidden_read_only = bdrv_is_read_only(s->hidden_disk->bs);
+        s->orig_secondary_read_only = bdrv_is_read_only(s->secondary_disk->bs);
     }
 
     bdrv_subtree_drained_begin(s->hidden_disk->bs);
     bdrv_subtree_drained_begin(s->secondary_disk->bs);
 
-    if (orig_hidden_flags != new_hidden_flags) {
-        reopen_queue = bdrv_reopen_queue(reopen_queue, s->hidden_disk->bs, NULL,
-                                         new_hidden_flags);
+    if (s->orig_hidden_read_only) {
+        int flags = bdrv_get_flags(s->hidden_disk->bs);
+        QDict *opts = qdict_new();
+        qdict_put_bool(opts, BDRV_OPT_READ_ONLY, !writable);
+        reopen_queue = bdrv_reopen_queue(reopen_queue, s->hidden_disk->bs,
+                                         opts, flags);
     }
 
-    if (!(orig_secondary_flags & BDRV_O_RDWR)) {
+    if (s->orig_secondary_read_only) {
+        int flags = bdrv_get_flags(s->secondary_disk->bs);
+        QDict *opts = qdict_new();
+        qdict_put_bool(opts, BDRV_OPT_READ_ONLY, !writable);
         reopen_queue = bdrv_reopen_queue(reopen_queue, s->secondary_disk->bs,
-                                         NULL, new_secondary_flags);
+                                         opts, flags);
     }
 
     if (reopen_queue) {
-- 
2.11.0

Re: [Qemu-devel] [PATCH v4 11/15] block: Clean up reopen_backing_file() in block/replication.c

[Max Reitz]

[-- Attachment #1: Type: text/plain, Size: 1067 bytes --]

On 07.11.18 13:59, Alberto Garcia wrote:
> This function is used to put the hidden and secondary disks in
> read-write mode before launching the backup job, and back in read-only
> mode afterwards.
> 
> This patch does the following changes:
> 
>   - Use an options QDict with the "read-only" option instead of
>     passing the changes as flags only.
> 
>   - Simplify the code (it was unnecessarily complicated and verbose).
> 
>   - Fix a bug due to which the secondary disk was not being put back
>     in read-only mode when writable=false (because in this case
>     orig_secondary_flags always had the BDRV_O_RDWR flag set).
> 
>   - Stop clearing the BDRV_O_INACTIVE flag.
> 
> The flags parameter to bdrv_reopen_queue() becomes redundant and we'll
> be able to get rid of it in a subsequent patch.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>  block/replication.c | 45 +++++++++++++++++++++------------------------
>  1 file changed, 21 insertions(+), 24 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>


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[Qemu-devel] [PATCH v4 12/15] block: Remove flags parameter from bdrv_reopen_queue()

[Alberto Garcia]

Now that all callers are passing all flag changes as QDict options,
the flags parameter is no longer necessary, so we can get rid of it.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block.c               | 5 +++--
 block/replication.c   | 6 ++----
 include/block/block.h | 3 +--
 qemu-io-cmds.c        | 2 +-
 4 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/block.c b/block.c
index 31de7b2299..8b401e1cf4 100644
--- a/block.c
+++ b/block.c
@@ -3041,8 +3041,9 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
 
 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
                                     BlockDriverState *bs,
-                                    QDict *options, int flags)
+                                    QDict *options)
 {
+    int flags = bdrv_get_flags(bs);
     return bdrv_reopen_queue_child(bs_queue, bs, options, flags,
                                    NULL, NULL, 0);
 }
@@ -3116,7 +3117,7 @@ int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
     qdict_put_bool(opts, BDRV_OPT_READ_ONLY, read_only);
 
     bdrv_subtree_drained_begin(bs);
-    queue = bdrv_reopen_queue(NULL, bs, opts, bdrv_get_flags(bs));
+    queue = bdrv_reopen_queue(NULL, bs, opts);
     ret = bdrv_reopen_multiple(bdrv_get_aio_context(bs), queue, errp);
     bdrv_subtree_drained_end(bs);
 
diff --git a/block/replication.c b/block/replication.c
index 481a225924..fdbfe47fa4 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -393,19 +393,17 @@ static void reopen_backing_file(BlockDriverState *bs, bool writable,
     bdrv_subtree_drained_begin(s->secondary_disk->bs);
 
     if (s->orig_hidden_read_only) {
-        int flags = bdrv_get_flags(s->hidden_disk->bs);
         QDict *opts = qdict_new();
         qdict_put_bool(opts, BDRV_OPT_READ_ONLY, !writable);
         reopen_queue = bdrv_reopen_queue(reopen_queue, s->hidden_disk->bs,
-                                         opts, flags);
+                                         opts);
     }
 
     if (s->orig_secondary_read_only) {
-        int flags = bdrv_get_flags(s->secondary_disk->bs);
         QDict *opts = qdict_new();
         qdict_put_bool(opts, BDRV_OPT_READ_ONLY, !writable);
         reopen_queue = bdrv_reopen_queue(reopen_queue, s->secondary_disk->bs,
-                                         opts, flags);
+                                         opts);
     }
 
     if (reopen_queue) {
diff --git a/include/block/block.h b/include/block/block.h
index de72c7a093..f70a843b72 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -299,8 +299,7 @@ BlockDriverState *bdrv_open(const char *filename, const char *reference,
 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name,
                                        int flags, Error **errp);
 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
-                                    BlockDriverState *bs,
-                                    QDict *options, int flags);
+                                    BlockDriverState *bs, QDict *options);
 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp);
 int bdrv_reopen_set_read_only(BlockDriverState *bs, bool read_only,
                               Error **errp);
diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index c9ae09d574..2c39124036 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -2075,7 +2075,7 @@ static int reopen_f(BlockBackend *blk, int argc, char **argv)
     }
 
     bdrv_subtree_drained_begin(bs);
-    brq = bdrv_reopen_queue(NULL, bs, opts, flags);
+    brq = bdrv_reopen_queue(NULL, bs, opts);
     bdrv_reopen_multiple(bdrv_get_aio_context(bs), brq, &local_err);
     bdrv_subtree_drained_end(bs);
 
-- 
2.11.0

[Qemu-devel] [PATCH v4 13/15] block: Stop passing flags to bdrv_reopen_queue_child()

[Alberto Garcia]

Now that all callers are passing the new options using the QDict we no
longer need the 'flags' parameter.

This patch makes the following changes:

   1) The update_options_from_flags() call is no longer necessary
      so it can be removed.

   2) The update_flags_from_options() call is now used in all cases,
      and is moved down a few lines so it happens after the options
      QDict contains the final set of values.

   3) The flags parameter is removed. Now the flags are initialized
      using the current value (for the top-level node) or the parent
      flags (after inherit_options()). In both cases the initial
      values are updated to reflect the new options in the QDict. This
      happens in bdrv_reopen_queue_child() (as explained above) and in
      bdrv_reopen_prepare().

Signed-off-by: Alberto Garcia <berto@igalia.com>
---
 block.c | 48 +++++++++++++++++++-----------------------------
 1 file changed, 19 insertions(+), 29 deletions(-)

diff --git a/block.c b/block.c
index 8b401e1cf4..8bc808d6f3 100644
--- a/block.c
+++ b/block.c
@@ -2912,7 +2912,6 @@ BlockDriverState *bdrv_open(const char *filename, const char *reference,
 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
                                                  BlockDriverState *bs,
                                                  QDict *options,
-                                                 int flags,
                                                  const BdrvChildRole *role,
                                                  QDict *parent_options,
                                                  int parent_flags)
@@ -2921,7 +2920,9 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
 
     BlockReopenQueueEntry *bs_entry;
     BdrvChild *child;
-    QDict *old_options, *explicit_options;
+    QDict *old_options, *explicit_options, *options_copy;
+    int flags;
+    QemuOpts *opts;
 
     /* Make sure that the caller remembered to use a drained section. This is
      * important to avoid graph changes between the recursive queuing here and
@@ -2947,22 +2948,11 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
     /*
      * Precedence of options:
      * 1. Explicitly passed in options (highest)
-     * 2. Set in flags (only for top level)
-     * 3. Retained from explicitly set options of bs
-     * 4. Inherited from parent node
-     * 5. Retained from effective options of bs
+     * 2. Retained from explicitly set options of bs
+     * 3. Inherited from parent node
+     * 4. Retained from effective options of bs
      */
 
-    if (!parent_options) {
-        /*
-         * Any setting represented by flags is always updated. If the
-         * corresponding QDict option is set, it takes precedence. Otherwise
-         * the flag is translated into a QDict option. The old setting of bs is
-         * not considered.
-         */
-        update_options_from_flags(options, flags);
-    }
-
     /* Old explicitly set values (don't overwrite by inherited value) */
     if (bs_entry) {
         old_options = qdict_clone_shallow(bs_entry->state.explicit_options);
@@ -2976,16 +2966,10 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
 
     /* Inherit from parent node */
     if (parent_options) {
-        QemuOpts *opts;
-        QDict *options_copy;
-        assert(!flags);
+        flags = 0;
         role->inherit_options(&flags, options, parent_flags, parent_options);
-        options_copy = qdict_clone_shallow(options);
-        opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
-        qemu_opts_absorb_qdict(opts, options_copy, NULL);
-        update_flags_from_options(&flags, opts);
-        qemu_opts_del(opts);
-        qobject_unref(options_copy);
+    } else {
+        flags = bdrv_get_flags(bs);
     }
 
     /* Old values are used for options that aren't set yet */
@@ -2993,6 +2977,14 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
     bdrv_join_options(bs, options, old_options);
     qobject_unref(old_options);
 
+    /* We have the final set of options so let's update the flags */
+    options_copy = qdict_clone_shallow(options);
+    opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort);
+    qemu_opts_absorb_qdict(opts, options_copy, NULL);
+    update_flags_from_options(&flags, opts);
+    qemu_opts_del(opts);
+    qobject_unref(options_copy);
+
     /* bdrv_open_inherit() sets and clears some additional flags internally */
     flags &= ~BDRV_O_PROTOCOL;
     if (flags & BDRV_O_RDWR) {
@@ -3032,7 +3024,7 @@ static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue,
         qdict_extract_subqdict(options, &new_child_options, child_key_dot);
         g_free(child_key_dot);
 
-        bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options, 0,
+        bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options,
                                 child->role, options, flags);
     }
 
@@ -3043,9 +3035,7 @@ BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
                                     BlockDriverState *bs,
                                     QDict *options)
 {
-    int flags = bdrv_get_flags(bs);
-    return bdrv_reopen_queue_child(bs_queue, bs, options, flags,
-                                   NULL, NULL, 0);
+    return bdrv_reopen_queue_child(bs_queue, bs, options, NULL, NULL, 0);
 }
 
 /*
-- 
2.11.0

Re: [Qemu-devel] [PATCH v4 13/15] block: Stop passing flags to bdrv_reopen_queue_child()

[Max Reitz]

[-- Attachment #1: Type: text/plain, Size: 1127 bytes --]

On 07.11.18 13:59, Alberto Garcia wrote:
> Now that all callers are passing the new options using the QDict we no
> longer need the 'flags' parameter.
> 
> This patch makes the following changes:
> 
>    1) The update_options_from_flags() call is no longer necessary
>       so it can be removed.
> 
>    2) The update_flags_from_options() call is now used in all cases,
>       and is moved down a few lines so it happens after the options
>       QDict contains the final set of values.
> 
>    3) The flags parameter is removed. Now the flags are initialized
>       using the current value (for the top-level node) or the parent
>       flags (after inherit_options()). In both cases the initial
>       values are updated to reflect the new options in the QDict. This
>       happens in bdrv_reopen_queue_child() (as explained above) and in
>       bdrv_reopen_prepare().
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>  block.c | 48 +++++++++++++++++++-----------------------------
>  1 file changed, 19 insertions(+), 29 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>


[-- Attachment #2: OpenPGP digital signature --]
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[Qemu-devel] [PATCH v4 14/15] block: Remove assertions from update_flags_from_options()

[Alberto Garcia]

This function takes three options (cache.direct, cache.no-flush and
read-only) from a QemuOpts object and updates the flags accordingly.

If any of those options is not set (because it was missing from the
original QDict or because it had an invalid value) then the function
aborts with a failed assertion:

   $ qemu-io -c 'reopen -o read-only=foo' hd.qcow2
   block.c:1126: update_flags_from_options: Assertion `qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT)' failed.
   Aborted

This assertion is unnecessary, and it forces any caller of
bdrv_reopen() to pass all the aforementioned three options. This may
have made sense in order to remove ambiguity when bdrv_reopen() was
taking both flags and options, but that's not the case anymore.

It's also unnecessary if we want to validate the option values,
because bdrv_reopen_prepare() already takes care of that, as we can
see if we remove the assertions:

   $ qemu-io -c 'reopen -o read-only=foo' hd.qcow2
   Parameter 'read-only' expects 'on' or 'off'

Signed-off-by: Alberto Garcia <berto@igalia.com>
---
 block.c                    | 4 ----
 tests/qemu-iotests/133     | 8 ++++++++
 tests/qemu-iotests/133.out | 6 ++++++
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/block.c b/block.c
index 8bc808d6f3..68f1e3b45e 100644
--- a/block.c
+++ b/block.c
@@ -1139,24 +1139,20 @@ static void update_flags_from_options(int *flags, QemuOpts *opts)
 {
     *flags &= ~BDRV_O_CACHE_MASK;
 
-    assert(qemu_opt_find(opts, BDRV_OPT_CACHE_NO_FLUSH));
     if (qemu_opt_get_bool_del(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
         *flags |= BDRV_O_NO_FLUSH;
     }
 
-    assert(qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT));
     if (qemu_opt_get_bool_del(opts, BDRV_OPT_CACHE_DIRECT, false)) {
         *flags |= BDRV_O_NOCACHE;
     }
 
     *flags &= ~BDRV_O_RDWR;
 
-    assert(qemu_opt_find(opts, BDRV_OPT_READ_ONLY));
     if (!qemu_opt_get_bool_del(opts, BDRV_OPT_READ_ONLY, false)) {
         *flags |= BDRV_O_RDWR;
     }
 
-    assert(qemu_opt_find(opts, BDRV_OPT_AUTO_READ_ONLY));
     if (qemu_opt_get_bool_del(opts, BDRV_OPT_AUTO_READ_ONLY, false)) {
         *flags |= BDRV_O_AUTO_RDONLY;
     }
diff --git a/tests/qemu-iotests/133 b/tests/qemu-iotests/133
index 14e6b3b972..59d5e2ea25 100755
--- a/tests/qemu-iotests/133
+++ b/tests/qemu-iotests/133
@@ -101,6 +101,14 @@ $QEMU_IO -c 'reopen -w -o read-only=on' $TEST_IMG
 $QEMU_IO -c 'reopen -c none -o cache.direct=on' $TEST_IMG
 $QEMU_IO -c 'reopen -c writeback -o cache.direct=on' $TEST_IMG
 $QEMU_IO -c 'reopen -c directsync -o cache.no-flush=on' $TEST_IMG
+
+echo
+echo "=== Check that invalid options are handled correctly ==="
+echo
+
+$QEMU_IO -c 'reopen -o read-only=foo' $TEST_IMG
+$QEMU_IO -c 'reopen -o cache.no-flush=bar' $TEST_IMG
+$QEMU_IO -c 'reopen -o cache.direct=baz' $TEST_IMG
 # success, all done
 echo "*** done"
 rm -f $seq.full
diff --git a/tests/qemu-iotests/133.out b/tests/qemu-iotests/133.out
index 48a9d087f0..551096a9c4 100644
--- a/tests/qemu-iotests/133.out
+++ b/tests/qemu-iotests/133.out
@@ -32,4 +32,10 @@ Cannot set both -r/-w and 'read-only'
 Cannot set both -c and the cache options
 Cannot set both -c and the cache options
 Cannot set both -c and the cache options
+
+=== Check that invalid options are handled correctly ===
+
+Parameter 'read-only' expects 'on' or 'off'
+Parameter 'cache.no-flush' expects 'on' or 'off'
+Parameter 'cache.direct' expects 'on' or 'off'
 *** done
-- 
2.11.0

Re: [Qemu-devel] [PATCH v4 14/15] block: Remove assertions from update_flags_from_options()

[Max Reitz]

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On 07.11.18 13:59, Alberto Garcia wrote:
> This function takes three options (cache.direct, cache.no-flush and
> read-only) from a QemuOpts object and updates the flags accordingly.

and auto-read-only now

> 
> If any of those options is not set (because it was missing from the
> original QDict or because it had an invalid value) then the function
> aborts with a failed assertion:
> 
>    $ qemu-io -c 'reopen -o read-only=foo' hd.qcow2
>    block.c:1126: update_flags_from_options: Assertion `qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT)' failed.
>    Aborted
> 
> This assertion is unnecessary, and it forces any caller of
> bdrv_reopen() to pass all the aforementioned three options. This may

*four

> have made sense in order to remove ambiguity when bdrv_reopen() was
> taking both flags and options, but that's not the case anymore.
> 
> It's also unnecessary if we want to validate the option values,
> because bdrv_reopen_prepare() already takes care of that, as we can
> see if we remove the assertions:
> 
>    $ qemu-io -c 'reopen -o read-only=foo' hd.qcow2
>    Parameter 'read-only' expects 'on' or 'off'
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>  block.c                    | 4 ----
>  tests/qemu-iotests/133     | 8 ++++++++
>  tests/qemu-iotests/133.out | 6 ++++++
>  3 files changed, 14 insertions(+), 4 deletions(-)

Hm, seems like one way to solve it and I can't really find issue with
it.  So, let's first give a

Reviewed-by: Max Reitz <mreitz@redhat.com>

However, I wonder why you dropped your patch from v1 for this.  It
seemed more reasonable to me.  You're basically trading half-updating
the flags for just not touching them at all (and the latter seems
better, even though it's all an error in the end anyway).

> diff --git a/block.c b/block.c
> index 8bc808d6f3..68f1e3b45e 100644
> --- a/block.c
> +++ b/block.c
> @@ -1139,24 +1139,20 @@ static void update_flags_from_options(int *flags, QemuOpts *opts)
>  {
>      *flags &= ~BDRV_O_CACHE_MASK;
>  
> -    assert(qemu_opt_find(opts, BDRV_OPT_CACHE_NO_FLUSH));
>      if (qemu_opt_get_bool_del(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
>          *flags |= BDRV_O_NO_FLUSH;
>      }
>  
> -    assert(qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT));
>      if (qemu_opt_get_bool_del(opts, BDRV_OPT_CACHE_DIRECT, false)) {
>          *flags |= BDRV_O_NOCACHE;
>      }
>  
>      *flags &= ~BDRV_O_RDWR;

Unrelated to this patch, but isn't BDRV_O_AUTO_RDONLY missing here?

Max

>  
> -    assert(qemu_opt_find(opts, BDRV_OPT_READ_ONLY));
>      if (!qemu_opt_get_bool_del(opts, BDRV_OPT_READ_ONLY, false)) {
>          *flags |= BDRV_O_RDWR;
>      }
>  
> -    assert(qemu_opt_find(opts, BDRV_OPT_AUTO_READ_ONLY));
>      if (qemu_opt_get_bool_del(opts, BDRV_OPT_AUTO_READ_ONLY, false)) {
>          *flags |= BDRV_O_AUTO_RDONLY;
>      }
> diff --git a/tests/qemu-iotests/133 b/tests/qemu-iotests/133
> index 14e6b3b972..59d5e2ea25 100755
> --- a/tests/qemu-iotests/133
> +++ b/tests/qemu-iotests/133
> @@ -101,6 +101,14 @@ $QEMU_IO -c 'reopen -w -o read-only=on' $TEST_IMG
>  $QEMU_IO -c 'reopen -c none -o cache.direct=on' $TEST_IMG
>  $QEMU_IO -c 'reopen -c writeback -o cache.direct=on' $TEST_IMG
>  $QEMU_IO -c 'reopen -c directsync -o cache.no-flush=on' $TEST_IMG
> +
> +echo
> +echo "=== Check that invalid options are handled correctly ==="
> +echo
> +
> +$QEMU_IO -c 'reopen -o read-only=foo' $TEST_IMG
> +$QEMU_IO -c 'reopen -o cache.no-flush=bar' $TEST_IMG
> +$QEMU_IO -c 'reopen -o cache.direct=baz' $TEST_IMG
>  # success, all done
>  echo "*** done"
>  rm -f $seq.full
> diff --git a/tests/qemu-iotests/133.out b/tests/qemu-iotests/133.out
> index 48a9d087f0..551096a9c4 100644
> --- a/tests/qemu-iotests/133.out
> +++ b/tests/qemu-iotests/133.out
> @@ -32,4 +32,10 @@ Cannot set both -r/-w and 'read-only'
>  Cannot set both -c and the cache options
>  Cannot set both -c and the cache options
>  Cannot set both -c and the cache options
> +
> +=== Check that invalid options are handled correctly ===
> +
> +Parameter 'read-only' expects 'on' or 'off'
> +Parameter 'cache.no-flush' expects 'on' or 'off'
> +Parameter 'cache.direct' expects 'on' or 'off'
>  *** done
> 



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Re: [Qemu-devel] [PATCH v4 14/15] block: Remove assertions from update_flags_from_options()

[Alberto Garcia]

On Sun 11 Nov 2018 10:01:05 PM CET, Max Reitz wrote:
> On 07.11.18 13:59, Alberto Garcia wrote:
>> This function takes three options (cache.direct, cache.no-flush and
>> read-only) from a QemuOpts object and updates the flags accordingly.
>
> and auto-read-only now

Oops, will update.

> Hm, seems like one way to solve it and I can't really find issue with
> it.  So, let's first give a
>
> Reviewed-by: Max Reitz <mreitz@redhat.com>
>
> However, I wonder why you dropped your patch from v1 for this.  It
> seemed more reasonable to me.  You're basically trading half-updating
> the flags for just not touching them at all (and the latter seems
> better, even though it's all an error in the end anyway).

The main reason why I'm doing this is because if we keep the assertions
then we're forced to have these four options always set, and I don't see
any reason why they would need to be.

It's not a problem now but it will be later on. Have a look at this
early implementation of qmp_x_blockdev_reopen():

   https://lists.gnu.org/archive/html/qemu-block/2018-06/msg00795.html

Here we need to explicitly set those options to false if they're
unset. 'false' is already the default value of all of them, so this
shouldn't be necessary, but if we don't do it we'd hit the assertions
that I'm removing in this patch.

Berto

Re: [Qemu-devel] [PATCH v4 14/15] block: Remove assertions from update_flags_from_options()

[Max Reitz]

[-- Attachment #1: Type: text/plain, Size: 1476 bytes --]

On 12.11.18 11:26, Alberto Garcia wrote:
> On Sun 11 Nov 2018 10:01:05 PM CET, Max Reitz wrote:
>> On 07.11.18 13:59, Alberto Garcia wrote:
>>> This function takes three options (cache.direct, cache.no-flush and
>>> read-only) from a QemuOpts object and updates the flags accordingly.
>>
>> and auto-read-only now
> 
> Oops, will update.
> 
>> Hm, seems like one way to solve it and I can't really find issue with
>> it.  So, let's first give a
>>
>> Reviewed-by: Max Reitz <mreitz@redhat.com>
>>
>> However, I wonder why you dropped your patch from v1 for this.  It
>> seemed more reasonable to me.  You're basically trading half-updating
>> the flags for just not touching them at all (and the latter seems
>> better, even though it's all an error in the end anyway).
> 
> The main reason why I'm doing this is because if we keep the assertions
> then we're forced to have these four options always set, and I don't see
> any reason why they would need to be.
> 
> It's not a problem now but it will be later on. Have a look at this
> early implementation of qmp_x_blockdev_reopen():
> 
>    https://lists.gnu.org/archive/html/qemu-block/2018-06/msg00795.html
> 
> Here we need to explicitly set those options to false if they're
> unset. 'false' is already the default value of all of them, so this
> shouldn't be necessary, but if we don't do it we'd hit the assertions
> that I'm removing in this patch.

OK, that makes sense.

Max


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Re: [Qemu-devel] [PATCH v4 14/15] block: Remove assertions from update_flags_from_options()

[Alberto Garcia]

On Sun 11 Nov 2018 10:01:05 PM CET, Max Reitz wrote:
>> -    assert(qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT));
>>      if (qemu_opt_get_bool_del(opts, BDRV_OPT_CACHE_DIRECT, false)) {
>>          *flags |= BDRV_O_NOCACHE;
>>      }
>>  
>>      *flags &= ~BDRV_O_RDWR;
>
> Unrelated to this patch, but isn't BDRV_O_AUTO_RDONLY missing here?

I forgot to mention, but I think you're right here. I'll include this
fix in the next version of the series.

Berto

[Qemu-devel] [PATCH v4 15/15] block: Assert that flags are up-to-date in bdrv_reopen_prepare()

[Alberto Garcia]

Towards the end of bdrv_reopen_queue_child(), before starting to
process the children, the update_flags_from_options() function is
called in order to have BDRVReopenState.flags in sync with the options
from the QDict.

This is necessary because during the reopen process flags must be
updated for all nodes in the queue so bdrv_is_writable_after_reopen()
and the permission checks work correctly.

Because of that, calling update_flags_from_options() again in
bdrv_reopen_prepare() doesn't really change the flags (they are
already up-to-date). But we need to call it in order to remove those
options from QemuOpts and that way indicate that they have been
processed.

Signed-off-by: Alberto Garcia <berto@igalia.com>
---
 block.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/block.c b/block.c
index 68f1e3b45e..03277b3d19 100644
--- a/block.c
+++ b/block.c
@@ -3178,6 +3178,7 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
                         Error **errp)
 {
     int ret = -1;
+    int old_flags;
     Error *local_err = NULL;
     BlockDriver *drv;
     QemuOpts *opts;
@@ -3203,7 +3204,12 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
         goto error;
     }
 
+    /* This was already called in bdrv_reopen_queue_child() so the flags
+     * are up-to-date. This time we simply want to remove the options from
+     * QemuOpts in order to indicate that they have been processed. */
+    old_flags = reopen_state->flags;
     update_flags_from_options(&reopen_state->flags, opts);
+    assert(old_flags == reopen_state->flags);
 
     discard = qemu_opt_get_del(opts, BDRV_OPT_DISCARD);
     if (discard != NULL) {
-- 
2.11.0

Re: [Qemu-devel] [PATCH v4 15/15] block: Assert that flags are up-to-date in bdrv_reopen_prepare()

[Max Reitz]

[-- Attachment #1: Type: text/plain, Size: 2217 bytes --]

On 07.11.18 13:59, Alberto Garcia wrote:
> Towards the end of bdrv_reopen_queue_child(), before starting to
> process the children, the update_flags_from_options() function is
> called in order to have BDRVReopenState.flags in sync with the options
> from the QDict.
> 
> This is necessary because during the reopen process flags must be
> updated for all nodes in the queue so bdrv_is_writable_after_reopen()
> and the permission checks work correctly.
> 
> Because of that, calling update_flags_from_options() again in
> bdrv_reopen_prepare() doesn't really change the flags (they are
> already up-to-date). But we need to call it in order to remove those
> options from QemuOpts and that way indicate that they have been
> processed.
> 
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> ---
>  block.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/block.c b/block.c
> index 68f1e3b45e..03277b3d19 100644
> --- a/block.c
> +++ b/block.c
> @@ -3178,6 +3178,7 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
>                          Error **errp)
>  {
>      int ret = -1;
> +    int old_flags;
>      Error *local_err = NULL;
>      BlockDriver *drv;
>      QemuOpts *opts;
> @@ -3203,7 +3204,12 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
>          goto error;
>      }
>  
> +    /* This was already called in bdrv_reopen_queue_child() so the flags
> +     * are up-to-date. This time we simply want to remove the options from
> +     * QemuOpts in order to indicate that they have been processed. */
> +    old_flags = reopen_state->flags;
>      update_flags_from_options(&reopen_state->flags, opts);
> +    assert(old_flags == reopen_state->flags);

Reviewed-by: Max Reitz <mreitz@redhat.com>

Although as my bike-shedding for today I'd like to say that I'd find it
more intuitive to store the "just remove the options" call result into
old_flags instead (or rather something renamed), i.e.

    flags_copy = reopen_state->flags;
    update_flags_from_options(&flags_copy, opts);
    assert(flags_copy == reopen_state->flags);

Not that it matters.

Max


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