block: consistently use bdrv_is_read_only()

It's better to use accessor function instead of bs->read_only directly.
In some places use bdrv_is_writable() instead of
checking both BDRV_O_RDWR set and BDRV_O_INACTIVE not set.

In bdrv_open_common() it's a bit strange to add one more variable, but
we are going to drop bs->read_only in the next patch, so new ro local
variable substitutes it here.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210527154056.70294-2-vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

@@ -1720,6 +1720,7 @@ static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file,
     QemuOpts *opts;
     BlockDriver *drv;
     Error *local_err = NULL;
+    bool ro;
 
     assert(bs->file == NULL);
     assert(options != NULL && bs->options != options);
@@ -1772,15 +1773,17 @@ static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file,
 
     bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
 
-    if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
-        if (!bs->read_only && bdrv_is_whitelisted(drv, true)) {
+    ro = bdrv_is_read_only(bs);
+
+    if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, ro)) {
+        if (!ro && bdrv_is_whitelisted(drv, true)) {
             ret = bdrv_apply_auto_read_only(bs, NULL, NULL);
         } else {
             ret = -ENOTSUP;
         }
         if (ret < 0) {
             error_setg(errp,
-                       !bs->read_only && bdrv_is_whitelisted(drv, true)
+                       !ro && bdrv_is_whitelisted(drv, true)
                        ? "Driver '%s' can only be used for read-only devices"
                        : "Driver '%s' is not whitelisted",
                        drv->format_name);
@@ -1792,7 +1795,7 @@ static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file,
     assert(qatomic_read(&bs->copy_on_read) == 0);
 
     if (bs->open_flags & BDRV_O_COPY_ON_READ) {
-        if (!bs->read_only) {
+        if (!ro) {
             bdrv_enable_copy_on_read(bs);
         } else {
             error_setg(errp, "Can't use copy-on-read on read-only device");

block/block-backend.c

@@ -2269,7 +2269,7 @@ void blk_update_root_state(BlockBackend *blk)
     assert(blk->root);
 
     blk->root_state.open_flags    = blk->root->bs->open_flags;
-    blk->root_state.read_only     = blk->root->bs->read_only;
+    blk->root_state.read_only     = bdrv_is_read_only(blk->root->bs);
     blk->root_state.detect_zeroes = blk->root->bs->detect_zeroes;
 }
 

block/commit.c

@@ -453,7 +453,7 @@ int bdrv_commit(BlockDriverState *bs)
         return -EBUSY;
     }
 
-    ro = backing_file_bs->read_only;
+    ro = bdrv_is_read_only(backing_file_bs);
 
     if (ro) {
         if (bdrv_reopen_set_read_only(backing_file_bs, false, NULL)) {

block/io.c

@@ -1973,7 +1973,7 @@ bdrv_co_write_req_prepare(BdrvChild *child, int64_t offset, int64_t bytes,
 
     bdrv_check_request(offset, bytes, &error_abort);
 
-    if (bs->read_only) {
+    if (bdrv_is_read_only(bs)) {
         return -EPERM;
     }
 
@@ -3406,7 +3406,7 @@ int coroutine_fn bdrv_co_truncate(BdrvChild *child, int64_t offset, bool exact,
     if (new_bytes) {
         bdrv_make_request_serialising(&req, 1);
     }
-    if (bs->read_only) {
+    if (bdrv_is_read_only(bs)) {
         error_setg(errp, "Image is read-only");
         ret = -EACCES;
         goto out;

block/qapi.c

@@ -59,7 +59,7 @@ BlockDeviceInfo *bdrv_block_device_info(BlockBackend *blk,
 
     info = g_malloc0(sizeof(*info));
     info->file                   = g_strdup(bs->filename);
-    info->ro                     = bs->read_only;
+    info->ro                     = bdrv_is_read_only(bs);
     info->drv                    = g_strdup(bs->drv->format_name);
     info->encrypted              = bs->encrypted;
 

block/qcow2-snapshot.c

@@ -1026,7 +1026,7 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs,
     int new_l1_bytes;
     int ret;
 
-    assert(bs->read_only);
+    assert(bdrv_is_read_only(bs));
 
     /* Search the snapshot */
     snapshot_index = find_snapshot_by_id_and_name(bs, snapshot_id, name);

block/qcow2.c

@@ -1723,8 +1723,7 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
 
     /* Clear unknown autoclear feature bits */
     update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK;
-    update_header =
-        update_header && !bs->read_only && !(flags & BDRV_O_INACTIVE);
+    update_header = update_header && bdrv_is_writable(bs);
     if (update_header) {
         s->autoclear_features &= QCOW2_AUTOCLEAR_MASK;
     }
@@ -1811,7 +1810,7 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
     bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE;
 
     /* Repair image if dirty */
-    if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only &&
+    if (!(flags & BDRV_O_CHECK) && bdrv_is_writable(bs) &&
         (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) {
         BdrvCheckResult result = {0};
 

block/snapshot.c

@@ -415,7 +415,7 @@ int bdrv_snapshot_load_tmp(BlockDriverState *bs,
         error_setg(errp, "snapshot_id and name are both NULL");
         return -EINVAL;
     }
-    if (!bs->read_only) {
+    if (!bdrv_is_read_only(bs)) {
         error_setg(errp, "Device is not readonly");
         return -EINVAL;
     }

block/vhdx-log.c

@@ -801,7 +801,7 @@ int vhdx_parse_log(BlockDriverState *bs, BDRVVHDXState *s, bool *flushed,
     }
 
     if (logs.valid) {
-        if (bs->read_only) {
+        if (bdrv_is_read_only(bs)) {
             bdrv_refresh_filename(bs);
             ret = -EPERM;
             error_setg(errp,