block/dirty-bitmaps: add block_dirty_bitmap_check function

Instead of checking against busy, inconsistent, or read only directly,
use a check function with permissions bits that let us streamline the
checks without reproducing them in many places.

Included in this patch are permissions changes that simply add the
inconsistent check to existing permissions call spots, without
addressing existing bugs.

In general, this means that busy+readonly checks become BDRV_BITMAP_DEFAULT,
which checks against all three conditions. busy-only checks become
BDRV_BITMAP_ALLOW_RO.

Notably, remove allows inconsistent bitmaps, so it doesn't follow the pattern.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190301191545.8728-4-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

block/dirty-bitmap.c

@@ -174,7 +174,7 @@ bool bdrv_dirty_bitmap_has_successor(BdrvDirtyBitmap *bitmap)
     return bitmap->successor;
 }
 
-bool bdrv_dirty_bitmap_busy(BdrvDirtyBitmap *bitmap)
+static bool bdrv_dirty_bitmap_busy(const BdrvDirtyBitmap *bitmap)
 {
     return bitmap->busy;
 }
@@ -236,6 +236,33 @@ static bool bdrv_dirty_bitmap_recording(BdrvDirtyBitmap *bitmap)
                                  !bitmap->successor->disabled);
 }
 
+int bdrv_dirty_bitmap_check(const BdrvDirtyBitmap *bitmap, uint32_t flags,
+                            Error **errp)
+{
+    if ((flags & BDRV_BITMAP_BUSY) && bdrv_dirty_bitmap_busy(bitmap)) {
+        error_setg(errp, "Bitmap '%s' is currently in use by another"
+                   " operation and cannot be used", bitmap->name);
+        return -1;
+    }
+
+    if ((flags & BDRV_BITMAP_RO) && bdrv_dirty_bitmap_readonly(bitmap)) {
+        error_setg(errp, "Bitmap '%s' is readonly and cannot be modified",
+                   bitmap->name);
+        return -1;
+    }
+
+    if ((flags & BDRV_BITMAP_INCONSISTENT) &&
+        bdrv_dirty_bitmap_inconsistent(bitmap)) {
+        error_setg(errp, "Bitmap '%s' is inconsistent and cannot be used",
+                   bitmap->name);
+        error_append_hint(errp, "Try block-dirty-bitmap-remove to delete"
+                          " this bitmap from disk");
+        return -1;
+    }
+
+    return 0;
+}
+
 /**
  * Create a successor bitmap destined to replace this bitmap after an operation.
  * Requires that the bitmap is not marked busy and has no successor.
@@ -248,9 +275,7 @@ int bdrv_dirty_bitmap_create_successor(BlockDriverState *bs,
     uint64_t granularity;
     BdrvDirtyBitmap *child;
 
-    if (bdrv_dirty_bitmap_busy(bitmap)) {
+    if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_BUSY, errp)) {
-        error_setg(errp, "Cannot create a successor for a bitmap that is "
-                   "in-use by an operation");
         return -1;
     }
     if (bdrv_dirty_bitmap_has_successor(bitmap)) {
@@ -796,17 +821,10 @@ void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
 
     qemu_mutex_lock(dest->mutex);
 
-    if (bdrv_dirty_bitmap_busy(dest)) {
+    if (bdrv_dirty_bitmap_check(dest, BDRV_BITMAP_DEFAULT, errp)) {
-        error_setg(errp, "Bitmap '%s' is currently in use by another"
-        " operation and cannot be modified", dest->name);
         goto out;
     }
 
-    if (bdrv_dirty_bitmap_readonly(dest)) {
-        error_setg(errp, "Bitmap '%s' is readonly and cannot be modified",
-                   dest->name);
-        goto out;
-    }
 
     if (!hbitmap_can_merge(dest->bitmap, src->bitmap)) {
         error_setg(errp, "Bitmaps are incompatible and can't be merged");

blockdev.c

@@ -2010,11 +2010,7 @@ static void block_dirty_bitmap_clear_prepare(BlkActionState *common,
         return;
     }
 
-    if (bdrv_dirty_bitmap_busy(state->bitmap)) {
+    if (bdrv_dirty_bitmap_check(state->bitmap, BDRV_BITMAP_DEFAULT, errp)) {
-        error_setg(errp, "Cannot modify a bitmap in use by another operation");
-        return;
-    } else if (bdrv_dirty_bitmap_readonly(state->bitmap)) {
-        error_setg(errp, "Cannot clear a readonly bitmap");
         return;
     }
 
@@ -2059,10 +2055,7 @@ static void block_dirty_bitmap_enable_prepare(BlkActionState *common,
         return;
     }
 
-    if (bdrv_dirty_bitmap_busy(state->bitmap)) {
+    if (bdrv_dirty_bitmap_check(state->bitmap, BDRV_BITMAP_ALLOW_RO, errp)) {
-        error_setg(errp,
-                   "Bitmap '%s' is currently in use by another operation"
-                   " and cannot be enabled", action->name);
         return;
     }
 
@@ -2100,10 +2093,7 @@ static void block_dirty_bitmap_disable_prepare(BlkActionState *common,
         return;
     }
 
-    if (bdrv_dirty_bitmap_busy(state->bitmap)) {
+    if (bdrv_dirty_bitmap_check(state->bitmap, BDRV_BITMAP_ALLOW_RO, errp)) {
-        error_setg(errp,
-                   "Bitmap '%s' is currently in use by another operation"
-                   " and cannot be disabled", action->name);
         return;
     }
 
@@ -2894,10 +2884,7 @@ void qmp_block_dirty_bitmap_remove(const char *node, const char *name,
         return;
     }
 
-    if (bdrv_dirty_bitmap_busy(bitmap)) {
+    if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_BUSY, errp)) {
-        error_setg(errp,
-                   "Bitmap '%s' is currently in use by another operation and"
-                   " cannot be removed", name);
         return;
     }
 
@@ -2933,13 +2920,7 @@ void qmp_block_dirty_bitmap_clear(const char *node, const char *name,
         return;
     }
 
-    if (bdrv_dirty_bitmap_busy(bitmap)) {
+    if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_DEFAULT, errp)) {
-        error_setg(errp,
-                   "Bitmap '%s' is currently in use by another operation"
-                   " and cannot be cleared", name);
-        return;
-    } else if (bdrv_dirty_bitmap_readonly(bitmap)) {
-        error_setg(errp, "Bitmap '%s' is readonly and cannot be cleared", name);
         return;
     }
 
@@ -2957,10 +2938,7 @@ void qmp_block_dirty_bitmap_enable(const char *node, const char *name,
         return;
     }
 
-    if (bdrv_dirty_bitmap_busy(bitmap)) {
+    if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_ALLOW_RO, errp)) {
-        error_setg(errp,
-                   "Bitmap '%s' is currently in use by another operation"
-                   " and cannot be enabled", name);
         return;
     }
 
@@ -2978,10 +2956,7 @@ void qmp_block_dirty_bitmap_disable(const char *node, const char *name,
         return;
     }
 
-    if (bdrv_dirty_bitmap_busy(bitmap)) {
+    if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_ALLOW_RO, errp)) {
-        error_setg(errp,
-                   "Bitmap '%s' is currently in use by another operation"
-                   " and cannot be disabled", name);
         return;
     }
 
@@ -3560,10 +3535,7 @@ static BlockJob *do_drive_backup(DriveBackup *backup, JobTxn *txn,
             bdrv_unref(target_bs);
             goto out;
         }
-        if (bdrv_dirty_bitmap_busy(bmap)) {
+        if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_ALLOW_RO, errp)) {
-            error_setg(errp,
-                       "Bitmap '%s' is currently in use by another operation"
-                       " and cannot be used for backup", backup->bitmap);
             goto out;
         }
     }
@@ -3673,10 +3645,7 @@ BlockJob *do_blockdev_backup(BlockdevBackup *backup, JobTxn *txn,
             error_setg(errp, "Bitmap '%s' could not be found", backup->bitmap);
             goto out;
         }
-        if (bdrv_dirty_bitmap_busy(bmap)) {
+        if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_ALLOW_RO, errp)) {
-            error_setg(errp,
-                       "Bitmap '%s' is currently in use by another operation"
-                       " and cannot be used for backup", backup->bitmap);
             goto out;
         }
     }

include/block/dirty-bitmap.h

@@ -5,6 +5,16 @@
 #include "qapi/qapi-types-block-core.h"
 #include "qemu/hbitmap.h"
 
+typedef enum BitmapCheckFlags {
+    BDRV_BITMAP_BUSY = 1,
+    BDRV_BITMAP_RO = 2,
+    BDRV_BITMAP_INCONSISTENT = 4,
+} BitmapCheckFlags;
+
+#define BDRV_BITMAP_DEFAULT (BDRV_BITMAP_BUSY | BDRV_BITMAP_RO |        \
+                             BDRV_BITMAP_INCONSISTENT)
+#define BDRV_BITMAP_ALLOW_RO (BDRV_BITMAP_BUSY | BDRV_BITMAP_INCONSISTENT)
+
 BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
                                           uint32_t granularity,
                                           const char *name,
@@ -24,6 +34,8 @@ BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap(BlockDriverState *bs,
 void bdrv_dirty_bitmap_enable_successor(BdrvDirtyBitmap *bitmap);
 BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs,
                                         const char *name);
+int bdrv_dirty_bitmap_check(const BdrvDirtyBitmap *bitmap, uint32_t flags,
+                            Error **errp);
 void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
 void bdrv_release_named_dirty_bitmaps(BlockDriverState *bs);
 void bdrv_remove_persistent_dirty_bitmap(BlockDriverState *bs,
@@ -93,7 +105,6 @@ bool bdrv_has_readonly_bitmaps(BlockDriverState *bs);
 bool bdrv_dirty_bitmap_get_autoload(const BdrvDirtyBitmap *bitmap);
 bool bdrv_dirty_bitmap_get_persistance(BdrvDirtyBitmap *bitmap);
 bool bdrv_dirty_bitmap_inconsistent(const BdrvDirtyBitmap *bitmap);
-bool bdrv_dirty_bitmap_busy(BdrvDirtyBitmap *bitmap);
 bool bdrv_has_changed_persistent_bitmaps(BlockDriverState *bs);
 BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BlockDriverState *bs,
                                         BdrvDirtyBitmap *bitmap);

migration/block-dirty-bitmap.c

@@ -274,6 +274,7 @@ static int init_dirty_bitmap_migration(void)
     BdrvDirtyBitmap *bitmap;
     DirtyBitmapMigBitmapState *dbms;
     BdrvNextIterator it;
+    Error *local_err = NULL;
 
     dirty_bitmap_mig_state.bulk_completed = false;
     dirty_bitmap_mig_state.prev_bs = NULL;
@@ -301,15 +302,9 @@ static int init_dirty_bitmap_migration(void)
                 goto fail;
             }
 
-            if (bdrv_dirty_bitmap_busy(bitmap)) {
+            if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_DEFAULT,
-                error_report("Can't migrate a bitmap that is in use by another operation: '%s'",
+                                        &local_err)) {
-                             bdrv_dirty_bitmap_name(bitmap));
+                error_report_err(local_err);
-                goto fail;
-            }
-
-            if (bdrv_dirty_bitmap_readonly(bitmap)) {
-                error_report("Can't migrate read-only dirty bitmap: '%s",
-                             bdrv_dirty_bitmap_name(bitmap));
                 goto fail;
             }
 

nbd/server.c

@@ -1510,8 +1510,7 @@ NBDExport *nbd_export_new(BlockDriverState *bs, uint64_t dev_offset,
             goto fail;
         }
 
-        if (bdrv_dirty_bitmap_busy(bm)) {
+        if (bdrv_dirty_bitmap_check(bm, BDRV_BITMAP_ALLOW_RO, errp)) {
-            error_setg(errp, "Bitmap '%s' is in use", bitmap);
             goto fail;
         }