--- /dev/null
+/*
+ * Block Dirty Bitmap
+ *
+ * Copyright (c) 2016 Red Hat. Inc
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qemu-common.h"
+#include "trace.h"
+#include "block/block_int.h"
+#include "block/blockjob.h"
+
+/**
+ * A BdrvDirtyBitmap can be in three possible states:
+ * (1) successor is NULL and disabled is false: full r/w mode
+ * (2) successor is NULL and disabled is true: read only mode ("disabled")
+ * (3) successor is set: frozen mode.
+ * A frozen bitmap cannot be renamed, deleted, anonymized, cleared, set,
+ * or enabled. A frozen bitmap can only abdicate() or reclaim().
+ */
+struct BdrvDirtyBitmap {
+ HBitmap *bitmap; /* Dirty sector bitmap implementation */
+ BdrvDirtyBitmap *successor; /* Anonymous child; implies frozen status */
+ char *name; /* Optional non-empty unique ID */
+ int64_t size; /* Size of the bitmap (Number of sectors) */
+ bool disabled; /* Bitmap is read-only */
+ QLIST_ENTRY(BdrvDirtyBitmap) list;
+};
+
+BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs, const char *name)
+{
+ BdrvDirtyBitmap *bm;
+
+ assert(name);
+ QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) {
+ if (bm->name && !strcmp(name, bm->name)) {
+ return bm;
+ }
+ }
+ return NULL;
+}
+
+void bdrv_dirty_bitmap_make_anon(BdrvDirtyBitmap *bitmap)
+{
+ assert(!bdrv_dirty_bitmap_frozen(bitmap));
+ g_free(bitmap->name);
+ bitmap->name = NULL;
+}
+
+BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
+ uint32_t granularity,
+ const char *name,
+ Error **errp)
+{
+ int64_t bitmap_size;
+ BdrvDirtyBitmap *bitmap;
+ uint32_t sector_granularity;
+
+ assert((granularity & (granularity - 1)) == 0);
+
+ if (name && bdrv_find_dirty_bitmap(bs, name)) {
+ error_setg(errp, "Bitmap already exists: %s", name);
+ return NULL;
+ }
+ sector_granularity = granularity >> BDRV_SECTOR_BITS;
+ assert(sector_granularity);
+ bitmap_size = bdrv_nb_sectors(bs);
+ if (bitmap_size < 0) {
+ error_setg_errno(errp, -bitmap_size, "could not get length of device");
+ errno = -bitmap_size;
+ return NULL;
+ }
+ bitmap = g_new0(BdrvDirtyBitmap, 1);
+ bitmap->bitmap = hbitmap_alloc(bitmap_size, ctz32(sector_granularity));
+ bitmap->size = bitmap_size;
+ bitmap->name = g_strdup(name);
+ bitmap->disabled = false;
+ QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
+ return bitmap;
+}
+
+bool bdrv_dirty_bitmap_frozen(BdrvDirtyBitmap *bitmap)
+{
+ return bitmap->successor;
+}
+
+bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap)
+{
+ return !(bitmap->disabled || bitmap->successor);
+}
+
+DirtyBitmapStatus bdrv_dirty_bitmap_status(BdrvDirtyBitmap *bitmap)
+{
+ if (bdrv_dirty_bitmap_frozen(bitmap)) {
+ return DIRTY_BITMAP_STATUS_FROZEN;
+ } else if (!bdrv_dirty_bitmap_enabled(bitmap)) {
+ return DIRTY_BITMAP_STATUS_DISABLED;
+ } else {
+ return DIRTY_BITMAP_STATUS_ACTIVE;
+ }
+}
+
+/**
+ * Create a successor bitmap destined to replace this bitmap after an operation.
+ * Requires that the bitmap is not frozen and has no successor.
+ */
+int bdrv_dirty_bitmap_create_successor(BlockDriverState *bs,
+ BdrvDirtyBitmap *bitmap, Error **errp)
+{
+ uint64_t granularity;
+ BdrvDirtyBitmap *child;
+
+ if (bdrv_dirty_bitmap_frozen(bitmap)) {
+ error_setg(errp, "Cannot create a successor for a bitmap that is "
+ "currently frozen");
+ return -1;
+ }
+ assert(!bitmap->successor);
+
+ /* Create an anonymous successor */
+ granularity = bdrv_dirty_bitmap_granularity(bitmap);
+ child = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);
+ if (!child) {
+ return -1;
+ }
+
+ /* Successor will be on or off based on our current state. */
+ child->disabled = bitmap->disabled;
+
+ /* Install the successor and freeze the parent */
+ bitmap->successor = child;
+ return 0;
+}
+
+/**
+ * For a bitmap with a successor, yield our name to the successor,
+ * delete the old bitmap, and return a handle to the new bitmap.
+ */
+BdrvDirtyBitmap *bdrv_dirty_bitmap_abdicate(BlockDriverState *bs,
+ BdrvDirtyBitmap *bitmap,
+ Error **errp)
+{
+ char *name;
+ BdrvDirtyBitmap *successor = bitmap->successor;
+
+ if (successor == NULL) {
+ error_setg(errp, "Cannot relinquish control if "
+ "there's no successor present");
+ return NULL;
+ }
+
+ name = bitmap->name;
+ bitmap->name = NULL;
+ successor->name = name;
+ bitmap->successor = NULL;
+ bdrv_release_dirty_bitmap(bs, bitmap);
+
+ return successor;
+}
+
+/**
+ * In cases of failure where we can no longer safely delete the parent,
+ * we may wish to re-join the parent and child/successor.
+ * The merged parent will be un-frozen, but not explicitly re-enabled.
+ */
+BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap(BlockDriverState *bs,
+ BdrvDirtyBitmap *parent,
+ Error **errp)
+{
+ BdrvDirtyBitmap *successor = parent->successor;
+
+ if (!successor) {
+ error_setg(errp, "Cannot reclaim a successor when none is present");
+ return NULL;
+ }
+
+ if (!hbitmap_merge(parent->bitmap, successor->bitmap)) {
+ error_setg(errp, "Merging of parent and successor bitmap failed");
+ return NULL;
+ }
+ bdrv_release_dirty_bitmap(bs, successor);
+ parent->successor = NULL;
+
+ return parent;
+}
+
+/**
+ * Truncates _all_ bitmaps attached to a BDS.
+ */
+void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
+{
+ BdrvDirtyBitmap *bitmap;
+ uint64_t size = bdrv_nb_sectors(bs);
+
+ QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
+ assert(!bdrv_dirty_bitmap_frozen(bitmap));
+ hbitmap_truncate(bitmap->bitmap, size);
+ bitmap->size = size;
+ }
+}
+
+static void bdrv_do_release_matching_dirty_bitmap(BlockDriverState *bs,
+ BdrvDirtyBitmap *bitmap,
+ bool only_named)
+{
+ BdrvDirtyBitmap *bm, *next;
+ QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
+ if ((!bitmap || bm == bitmap) && (!only_named || bm->name)) {
+ assert(!bdrv_dirty_bitmap_frozen(bm));
+ QLIST_REMOVE(bm, list);
+ hbitmap_free(bm->bitmap);
+ g_free(bm->name);
+ g_free(bm);
+
+ if (bitmap) {
+ return;
+ }
+ }
+ }
+}
+
+void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
+{
+ bdrv_do_release_matching_dirty_bitmap(bs, bitmap, false);
+}
+
+/**
+ * Release all named dirty bitmaps attached to a BDS (for use in bdrv_close()).
+ * There must not be any frozen bitmaps attached.
+ */
+void bdrv_release_named_dirty_bitmaps(BlockDriverState *bs)
+{
+ bdrv_do_release_matching_dirty_bitmap(bs, NULL, true);
+}
+
+void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
+{
+ assert(!bdrv_dirty_bitmap_frozen(bitmap));
+ bitmap->disabled = true;
+}
+
+void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
+{
+ assert(!bdrv_dirty_bitmap_frozen(bitmap));
+ bitmap->disabled = false;
+}
+
+BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
+{
+ BdrvDirtyBitmap *bm;
+ BlockDirtyInfoList *list = NULL;
+ BlockDirtyInfoList **plist = &list;
+
+ QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) {
+ BlockDirtyInfo *info = g_new0(BlockDirtyInfo, 1);
+ BlockDirtyInfoList *entry = g_new0(BlockDirtyInfoList, 1);
+ info->count = bdrv_get_dirty_count(bm);
+ info->granularity = bdrv_dirty_bitmap_granularity(bm);
+ info->has_name = !!bm->name;
+ info->name = g_strdup(bm->name);
+ info->status = bdrv_dirty_bitmap_status(bm);
+ entry->value = info;
+ *plist = entry;
+ plist = &entry->next;
+ }
+
+ return list;
+}
+
+int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
+ int64_t sector)
+{
+ if (bitmap) {
+ return hbitmap_get(bitmap->bitmap, sector);
+ } else {
+ return 0;
+ }
+}
+
+/**
+ * Chooses a default granularity based on the existing cluster size,
+ * but clamped between [4K, 64K]. Defaults to 64K in the case that there
+ * is no cluster size information available.
+ */
+uint32_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs)
+{
+ BlockDriverInfo bdi;
+ uint32_t granularity;
+
+ if (bdrv_get_info(bs, &bdi) >= 0 && bdi.cluster_size > 0) {
+ granularity = MAX(4096, bdi.cluster_size);
+ granularity = MIN(65536, granularity);
+ } else {
+ granularity = 65536;
+ }
+
+ return granularity;
+}
+
+uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap)
+{
+ return BDRV_SECTOR_SIZE << hbitmap_granularity(bitmap->bitmap);
+}
+
+void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, HBitmapIter *hbi)
+{
+ hbitmap_iter_init(hbi, bitmap->bitmap, 0);
+}
+
+void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
+ int64_t cur_sector, int nr_sectors)
+{
+ assert(bdrv_dirty_bitmap_enabled(bitmap));
+ hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
+}
+
+void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
+ int64_t cur_sector, int nr_sectors)
+{
+ assert(bdrv_dirty_bitmap_enabled(bitmap));
+ hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
+}
+
+void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)
+{
+ assert(bdrv_dirty_bitmap_enabled(bitmap));
+ if (!out) {
+ hbitmap_reset_all(bitmap->bitmap);
+ } else {
+ HBitmap *backup = bitmap->bitmap;
+ bitmap->bitmap = hbitmap_alloc(bitmap->size,
+ hbitmap_granularity(backup));
+ *out = backup;
+ }
+}
+
+void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in)
+{
+ HBitmap *tmp = bitmap->bitmap;
+ assert(bdrv_dirty_bitmap_enabled(bitmap));
+ bitmap->bitmap = in;
+ hbitmap_free(tmp);
+}
+
+void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
+ int nr_sectors)
+{
+ BdrvDirtyBitmap *bitmap;
+ QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
+ if (!bdrv_dirty_bitmap_enabled(bitmap)) {
+ continue;
+ }
+ hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
+ }
+}
+
+/**
+ * Advance an HBitmapIter to an arbitrary offset.
+ */
+void bdrv_set_dirty_iter(HBitmapIter *hbi, int64_t offset)
+{
+ assert(hbi->hb);
+ hbitmap_iter_init(hbi, hbi->hb, offset);
+}
+
+int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap)
+{
+ return hbitmap_count(bitmap->bitmap);
+}
Code Review / kvmfornfv.git / blobdiff