[Qemu-devel] [PATCH 08/20] block: Always set writeback mode in blk_new_open()

[Kevin Wolf <kwolf@redhat.com>]

All callers of blk_new_open() either don't rely on the WCE bit set after
blk_new_open() because they explicitly set it anyway, or they pass
BDRV_O_CACHE_WB unconditionally.

This patch changes blk_new_open() so that it always enables writeback
mode and asserts that BDRV_O_CACHE_WB is clear. For those callers that
used to pass BDRV_O_CACHE_WB unconditionally, the flag is removed now.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/block-backend.c | 4 ++++
 block/parallels.c     | 3 +--
 block/qcow.c          | 3 +--
 block/qcow2.c         | 9 +++------
 block/qed.c           | 3 +--
 block/sheepdog.c      | 5 ++---
 block/vdi.c           | 3 +--
 block/vhdx.c          | 3 +--
 block/vmdk.c          | 8 +++-----
 block/vpc.c           | 3 +--
 blockdev.c            | 1 +
 11 files changed, 19 insertions(+), 26 deletions(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index dca21d1..ffa5856 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -147,6 +147,8 @@ BlockBackend *blk_new_open(const char *filename, const char *reference,
     BlockBackend *blk;
     int ret;
 
+    assert((flags & BDRV_O_CACHE_WB) == 0);
+
     blk = blk_new_with_bs(errp);
     if (!blk) {
         QDECREF(options);
@@ -159,6 +161,8 @@ BlockBackend *blk_new_open(const char *filename, const char *reference,
         return NULL;
     }
 
+    blk_set_enable_write_cache(blk, true);
+
     return blk;
 }
 
diff --git a/block/parallels.c b/block/parallels.c
index b322d05..fc18bd7 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -479,8 +479,7 @@ static int parallels_create(const char *filename, QemuOpts *opts, Error **errp)
     }
 
     file = blk_new_open(filename, NULL, NULL,
-                        BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL,
-                        &local_err);
+                        BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
     if (file == NULL) {
         error_propagate(errp, local_err);
         return -EIO;
diff --git a/block/qcow.c b/block/qcow.c
index 73cf8a7..07dd867 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -794,8 +794,7 @@ static int qcow_create(const char *filename, QemuOpts *opts, Error **errp)
     }
 
     qcow_blk = blk_new_open(filename, NULL, NULL,
-                            BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL,
-                            &local_err);
+                            BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
     if (qcow_blk == NULL) {
         error_propagate(errp, local_err);
         ret = -EIO;
diff --git a/block/qcow2.c b/block/qcow2.c
index 5f4fea6..4363f78 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2160,8 +2160,7 @@ static int qcow2_create2(const char *filename, int64_t total_size,
     }
 
     blk = blk_new_open(filename, NULL, NULL,
-                       BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL,
-                       &local_err);
+                       BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
     if (blk == NULL) {
         error_propagate(errp, local_err);
         return -EIO;
@@ -2225,8 +2224,7 @@ static int qcow2_create2(const char *filename, int64_t total_size,
     options = qdict_new();
     qdict_put(options, "driver", qstring_from_str("qcow2"));
     blk = blk_new_open(filename, NULL, options,
-                       BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH,
-                       &local_err);
+                       BDRV_O_RDWR | BDRV_O_NO_FLUSH, &local_err);
     if (blk == NULL) {
         error_propagate(errp, local_err);
         ret = -EIO;
@@ -2287,8 +2285,7 @@ static int qcow2_create2(const char *filename, int64_t total_size,
     options = qdict_new();
     qdict_put(options, "driver", qstring_from_str("qcow2"));
     blk = blk_new_open(filename, NULL, options,
-                       BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_BACKING,
-                       &local_err);
+                       BDRV_O_RDWR | BDRV_O_NO_BACKING, &local_err);
     if (blk == NULL) {
         error_propagate(errp, local_err);
         ret = -EIO;
diff --git a/block/qed.c b/block/qed.c
index 5b24a97..091d207 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -575,8 +575,7 @@ static int qed_create(const char *filename, uint32_t cluster_size,
     }
 
     blk = blk_new_open(filename, NULL, NULL,
-                       BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL,
-                       &local_err);
+                       BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
     if (blk == NULL) {
         error_propagate(errp, local_err);
         return -EIO;
diff --git a/block/sheepdog.c b/block/sheepdog.c
index a3aeae4..4b1bfc9 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -1647,8 +1647,7 @@ static int sd_prealloc(const char *filename, Error **errp)
     int ret;
 
     blk = blk_new_open(filename, NULL, NULL,
-                       BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL,
-                       errp);
+                       BDRV_O_RDWR | BDRV_O_PROTOCOL, errp);
     if (blk == NULL) {
         ret = -EIO;
         goto out_with_err_set;
@@ -1844,7 +1843,7 @@ static int sd_create(const char *filename, QemuOpts *opts,
         }
 
         blk = blk_new_open(backing_file, NULL, NULL,
-                           BDRV_O_PROTOCOL | BDRV_O_CACHE_WB, errp);
+                           BDRV_O_PROTOCOL, errp);
         if (blk == NULL) {
             ret = -EIO;
             goto out;
diff --git a/block/vdi.c b/block/vdi.c
index df9fa47..1791f22 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -769,8 +769,7 @@ static int vdi_create(const char *filename, QemuOpts *opts, Error **errp)
     }
 
     blk = blk_new_open(filename, NULL, NULL,
-                       BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL,
-                       &local_err);
+                       BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
     if (blk == NULL) {
         error_propagate(errp, local_err);
         ret = -EIO;
diff --git a/block/vhdx.c b/block/vhdx.c
index 78fe56c..7d1bddc 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -1839,8 +1839,7 @@ static int vhdx_create(const char *filename, QemuOpts *opts, Error **errp)
     }
 
     blk = blk_new_open(filename, NULL, NULL,
-                       BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL,
-                       &local_err);
+                       BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
     if (blk == NULL) {
         error_propagate(errp, local_err);
         ret = -EIO;
diff --git a/block/vmdk.c b/block/vmdk.c
index 80f0338..60f4d79 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -1662,8 +1662,7 @@ static int vmdk_create_extent(const char *filename, int64_t filesize,
     }
 
     blk = blk_new_open(filename, NULL, NULL,
-                       BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL,
-                       &local_err);
+                       BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
     if (blk == NULL) {
         error_propagate(errp, local_err);
         ret = -EIO;
@@ -1947,7 +1946,7 @@ static int vmdk_create(const char *filename, QemuOpts *opts, Error **errp)
         }
 
         blk = blk_new_open(full_backing, NULL, NULL,
-                           BDRV_O_NO_BACKING | BDRV_O_CACHE_WB, errp);
+                           BDRV_O_NO_BACKING, errp);
         g_free(full_backing);
         if (blk == NULL) {
             ret = -EIO;
@@ -2019,8 +2018,7 @@ static int vmdk_create(const char *filename, QemuOpts *opts, Error **errp)
     }
 
     new_blk = blk_new_open(filename, NULL, NULL,
-                           BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL,
-                           &local_err);
+                           BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
     if (new_blk == NULL) {
         error_propagate(errp, local_err);
         ret = -EIO;
diff --git a/block/vpc.c b/block/vpc.c
index 8435205..0429528 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -889,8 +889,7 @@ static int vpc_create(const char *filename, QemuOpts *opts, Error **errp)
     }
 
     blk = blk_new_open(filename, NULL, NULL,
-                       BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL,
-                       &local_err);
+                       BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
     if (blk == NULL) {
         error_propagate(errp, local_err);
         ret = -EIO;
diff --git a/blockdev.c b/blockdev.c
index 70c3add..10eefda 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -596,6 +596,7 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
         qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_WB, writethrough ? "off" : "on");
         qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_DIRECT, "off");
         qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_NO_FLUSH, "off");
+        assert((bdrv_flags & BDRV_O_CACHE_MASK) == 0);
 
         if (runstate_check(RUN_STATE_INMIGRATE)) {
             bdrv_flags |= BDRV_O_INACTIVE;
-- 
1.8.3.1