[Qemu-devel] [PATCH v2 00/12] make dirty-bitmap byte-based

[Qemu-devel] [PATCH v2 00/12] make dirty-bitmap byte-based

[Eric Blake]

There are patches floating around to add NBD_CMD_BLOCK_STATUS,
but NBD wants to report status on byte granularity (even if the
reporting will probably be naturally aligned to sectors or even
much higher levels).  I've therefore started the task of
converting our block status code to report at a byte granularity
rather than sectors.

This is part two of that conversion: dirty-bitmap. Other parts
include bdrv_is_allocated (at v2 [1]) and replacing
bdrv_get_block_status with a byte based callback in all the
drivers (at v1, needs a rebase [2]).

Available as a tag at:
git fetch git://repo.or.cz/qemu/ericb.git nbd-byte-dirty-v2

No change to the code itself since v1 [3], just tweaking commit
messages and adding John's Reviewed-by tags, and making sure it
still rebases cleanly on top of Max's block branch.

[1] https://lists.gnu.org/archive/html/qemu-devel/2017-05/msg02573.html
[2] https://lists.gnu.org/archive/html/qemu-devel/2017-04/msg02642.html
[3] https://lists.gnu.org/archive/html/qemu-devel/2017-04/msg02163.html

Eric Blake (12):
  dirty-bitmap: Report BlockDirtyInfo.count in bytes, as documented
  migration: Don't lose errno across aio context changes
  dirty-bitmap: Drop unused functions
  dirty-bitmap: Track size in bytes
  dirty-bitmap: Set iterator start by offset, not sector
  dirty-bitmap: Change bdrv_dirty_iter_next() to report byte offset
  dirty-bitmap: Change bdrv_get_dirty_count() to report bytes
  dirty-bitmap: Change bdrv_get_dirty() to take bytes
  dirty-bitmap: Change bdrv_[re]set_dirty_bitmap() to use bytes
  mirror: Switch mirror_dirty_init() to byte-based iteration
  dirty-bitmap: Switch bdrv_set_dirty() to bytes
  dirty-bitmap: Convert internal hbitmap size/granularity

 include/block/block_int.h    |  2 +-
 include/block/dirty-bitmap.h | 21 ++++-------
 block/backup.c               |  7 ++--
 block/dirty-bitmap.c         | 83 ++++++++++++--------------------------------
 block/io.c                   |  6 ++--
 block/mirror.c               | 73 +++++++++++++++++---------------------
 migration/block.c            | 14 ++++----
 7 files changed, 74 insertions(+), 132 deletions(-)

-- 
2.9.4

[Qemu-devel] [PATCH v2 01/12] dirty-bitmap: Report BlockDirtyInfo.count in bytes, as documented

[Eric Blake]

We've been documenting the value in bytes since its introduction
in commit b9a9b3a4 (v1.3), where it was actually reported in bytes.

Commit e4654d2 (v2.0) then removed things from block/qapi.c, in
preparation for a rewrite to a list of dirty sectors in the next
commit 21b5683 in block.c, but the new code mistakenly started
reporting in sectors.

Fixes: https://bugzilla.redhat.com/1441460

CC: qemu-stable@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

---
Too late for 2.9, since the regression has been unnoticed for
nine releases. But worth putting in 2.9.1.

v2: no change
---
 block/dirty-bitmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 519737c..6d8ce5f 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -345,7 +345,7 @@ BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
     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->count = bdrv_get_dirty_count(bm) << BDRV_SECTOR_BITS;
         info->granularity = bdrv_dirty_bitmap_granularity(bm);
         info->has_name = !!bm->name;
         info->name = g_strdup(bm->name);
-- 
2.9.4

[Qemu-devel] [PATCH v2 02/12] migration: Don't lose errno across aio context changes

[Eric Blake]

set_dirty_tracking() was assuming that the errno value set by
bdrv_create_dirty_bitmap() would not be corrupted by either
blk_get_aio_context() or aio_context_release().  Rather than
audit whether this assumption is safe, rewrite the code to just
grab the value of errno sooner.

CC: qemu-stable@nongnu.org
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>

---
v2: fix commit message typo, no code change
---
 migration/block.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/migration/block.c b/migration/block.c
index 8d79d84..ecc838a 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -350,9 +350,9 @@ static int set_dirty_tracking(void)
         aio_context_acquire(blk_get_aio_context(bmds->blk));
         bmds->dirty_bitmap = bdrv_create_dirty_bitmap(blk_bs(bmds->blk),
                                                       BLOCK_SIZE, NULL, NULL);
+        ret = -errno;
         aio_context_release(blk_get_aio_context(bmds->blk));
         if (!bmds->dirty_bitmap) {
-            ret = -errno;
             goto fail;
         }
     }
-- 
2.9.4

Re: [Qemu-devel] [PATCH v2 02/12] migration: Don't lose errno across aio context changes

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 844 bytes --]

On 05/16/2017 03:47 PM, Eric Blake wrote:
> set_dirty_tracking() was assuming that the errno value set by
> bdrv_create_dirty_bitmap() would not be corrupted by either
> blk_get_aio_context() or aio_context_release().  Rather than
> audit whether this assumption is safe, rewrite the code to just
> grab the value of errno sooner.
> 
> CC: qemu-stable@nongnu.org
> Signed-off-by: Eric Blake <eblake@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>
> Reviewed-by: Juan Quintela <quintela@redhat.com>
> 

This may still be appropriate for 2.9.1, but is no longer needed on
master thanks to Paolo's work in commit 2119882c7e.

I'll have to rebase and re-send this series, one patch shorter.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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[Qemu-devel] [PATCH v2 03/12] dirty-bitmap: Drop unused functions

[Eric Blake]

We had several functions that no one is currently using, and which
use sector-based interfaces.  I'm trying to convert towards byte-based
interfaces, so it's easier to just drop the unused functions:

bdrv_dirty_bitmap_size
bdrv_dirty_bitmap_get_meta
bdrv_dirty_bitmap_reset_meta
bdrv_dirty_bitmap_meta_granularity

Vladimir may re-add bdrv_dirty_bitmap_size() for persistent
bitmaps, but has agreed to do so with byte rather than sector
access at the point where it is needed.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

---
v2: tweak commit message based on review, no code change
---
 include/block/dirty-bitmap.h |  8 --------
 block/dirty-bitmap.c         | 34 ----------------------------------
 2 files changed, 42 deletions(-)

diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
index 9dea14b..a83979d 100644
--- a/include/block/dirty-bitmap.h
+++ b/include/block/dirty-bitmap.h
@@ -30,11 +30,9 @@ void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap);
 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs);
 uint32_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs);
 uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap);
-uint32_t bdrv_dirty_bitmap_meta_granularity(BdrvDirtyBitmap *bitmap);
 bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap);
 bool bdrv_dirty_bitmap_frozen(BdrvDirtyBitmap *bitmap);
 const char *bdrv_dirty_bitmap_name(const BdrvDirtyBitmap *bitmap);
-int64_t bdrv_dirty_bitmap_size(const BdrvDirtyBitmap *bitmap);
 DirtyBitmapStatus bdrv_dirty_bitmap_status(BdrvDirtyBitmap *bitmap);
 int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                    int64_t sector);
@@ -42,12 +40,6 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
                            int64_t cur_sector, int64_t nr_sectors);
 void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
                              int64_t cur_sector, int64_t nr_sectors);
-int bdrv_dirty_bitmap_get_meta(BlockDriverState *bs,
-                               BdrvDirtyBitmap *bitmap, int64_t sector,
-                               int nb_sectors);
-void bdrv_dirty_bitmap_reset_meta(BlockDriverState *bs,
-                                  BdrvDirtyBitmap *bitmap, int64_t sector,
-                                  int nb_sectors);
 BdrvDirtyBitmapIter *bdrv_dirty_meta_iter_new(BdrvDirtyBitmap *bitmap);
 BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
                                          uint64_t first_sector);
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 6d8ce5f..32698d5 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -130,35 +130,6 @@ void bdrv_release_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap)
     bitmap->meta = NULL;
 }

-int bdrv_dirty_bitmap_get_meta(BlockDriverState *bs,
-                               BdrvDirtyBitmap *bitmap, int64_t sector,
-                               int nb_sectors)
-{
-    uint64_t i;
-    int sectors_per_bit = 1 << hbitmap_granularity(bitmap->meta);
-
-    /* To optimize: we can make hbitmap to internally check the range in a
-     * coarse level, or at least do it word by word. */
-    for (i = sector; i < sector + nb_sectors; i += sectors_per_bit) {
-        if (hbitmap_get(bitmap->meta, i)) {
-            return true;
-        }
-    }
-    return false;
-}
-
-void bdrv_dirty_bitmap_reset_meta(BlockDriverState *bs,
-                                  BdrvDirtyBitmap *bitmap, int64_t sector,
-                                  int nb_sectors)
-{
-    hbitmap_reset(bitmap->meta, sector, nb_sectors);
-}
-
-int64_t bdrv_dirty_bitmap_size(const BdrvDirtyBitmap *bitmap)
-{
-    return bitmap->size;
-}
-
 const char *bdrv_dirty_bitmap_name(const BdrvDirtyBitmap *bitmap)
 {
     return bitmap->name;
@@ -393,11 +364,6 @@ uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap)
     return BDRV_SECTOR_SIZE << hbitmap_granularity(bitmap->bitmap);
 }

-uint32_t bdrv_dirty_bitmap_meta_granularity(BdrvDirtyBitmap *bitmap)
-{
-    return BDRV_SECTOR_SIZE << hbitmap_granularity(bitmap->meta);
-}
-
 BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
                                          uint64_t first_sector)
 {
-- 
2.9.4

[Qemu-devel] [PATCH v2 04/12] dirty-bitmap: Track size in bytes

[Eric Blake]

We are still using an internal hbitmap that tracks a size in sectors,
with the granularity scaled down accordingly, because it lets us
use a shortcut for our iterators which are currently sector-based.
But there's no reason we can't track the dirty bitmap size in bytes,
since it is an internal-only variable.

Use is_power_of_2() while at it, instead of open-coding that.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

---
v2: tweak commit message, no code change
---
 block/dirty-bitmap.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 32698d5..a413df1 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -41,7 +41,7 @@ struct BdrvDirtyBitmap {
     HBitmap *meta;              /* Meta dirty bitmap */
     BdrvDirtyBitmap *successor; /* Anonymous child; implies frozen status */
     char *name;                 /* Optional non-empty unique ID */
-    int64_t size;               /* Size of the bitmap (Number of sectors) */
+    int64_t size;               /* Size of the bitmap, in bytes */
     bool disabled;              /* Bitmap is read-only */
     int active_iterators;       /* How many iterators are active */
     QLIST_ENTRY(BdrvDirtyBitmap) list;
@@ -79,24 +79,26 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
 {
     int64_t bitmap_size;
     BdrvDirtyBitmap *bitmap;
-    uint32_t sector_granularity;

-    assert((granularity & (granularity - 1)) == 0);
+    assert(is_power_of_2(granularity) && granularity >= BDRV_SECTOR_SIZE);

     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);
+    bitmap_size = bdrv_getlength(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));
+    /*
+     * TODO - let hbitmap track full granularity. For now, it is tracking
+     * only sector granularity, as a shortcut for our iterators.
+     */
+    bitmap->bitmap = hbitmap_alloc(bitmap_size >> BDRV_SECTOR_BITS,
+                                   ctz32(granularity) - BDRV_SECTOR_BITS);
     bitmap->size = bitmap_size;
     bitmap->name = g_strdup(name);
     bitmap->disabled = false;
@@ -246,12 +248,13 @@ BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap(BlockDriverState *bs,
 void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
 {
     BdrvDirtyBitmap *bitmap;
-    uint64_t size = bdrv_nb_sectors(bs);
+    int64_t size = bdrv_getlength(bs);

+    assert(size >= 0);
     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
         assert(!bdrv_dirty_bitmap_frozen(bitmap));
         assert(!bitmap->active_iterators);
-        hbitmap_truncate(bitmap->bitmap, size);
+        hbitmap_truncate(bitmap->bitmap, size >> BDRV_SECTOR_BITS);
         bitmap->size = size;
     }
 }
@@ -419,7 +422,7 @@ void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)
         hbitmap_reset_all(bitmap->bitmap);
     } else {
         HBitmap *backup = bitmap->bitmap;
-        bitmap->bitmap = hbitmap_alloc(bitmap->size,
+        bitmap->bitmap = hbitmap_alloc(bitmap->size >> BDRV_SECTOR_BITS,
                                        hbitmap_granularity(backup));
         *out = backup;
     }
-- 
2.9.4

[Qemu-devel] [PATCH v2 05/12] dirty-bitmap: Set iterator start by offset, not sector

[Eric Blake]

All callers to bdrv_dirty_iter_new() passed 0 for their initial
starting point, drop that parameter.

All callers to bdrv_set_dirty_iter() were scaling an offset to
a sector number; move the scaling to occur internally to dirty
bitmap code instead.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

---
v2: no change
---
 include/block/dirty-bitmap.h | 5 ++---
 block/backup.c               | 5 ++---
 block/dirty-bitmap.c         | 9 ++++-----
 block/mirror.c               | 4 ++--
 4 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
index a83979d..efcec60 100644
--- a/include/block/dirty-bitmap.h
+++ b/include/block/dirty-bitmap.h
@@ -41,11 +41,10 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
 void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
                              int64_t cur_sector, int64_t nr_sectors);
 BdrvDirtyBitmapIter *bdrv_dirty_meta_iter_new(BdrvDirtyBitmap *bitmap);
-BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
-                                         uint64_t first_sector);
+BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap);
 void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter);
 int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter);
-void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t sector_num);
+void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t offset);
 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
 int64_t bdrv_get_meta_dirty_count(BdrvDirtyBitmap *bitmap);
 void bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
diff --git a/block/backup.c b/block/backup.c
index b8b76e5..70126b8 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -372,7 +372,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)

     granularity = bdrv_dirty_bitmap_granularity(job->sync_bitmap);
     clusters_per_iter = MAX((granularity / job->cluster_size), 1);
-    dbi = bdrv_dirty_iter_new(job->sync_bitmap, 0);
+    dbi = bdrv_dirty_iter_new(job->sync_bitmap);

     /* Find the next dirty sector(s) */
     while ((offset = bdrv_dirty_iter_next(dbi) * BDRV_SECTOR_SIZE) >= 0) {
@@ -403,8 +403,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
         /* If the bitmap granularity is smaller than the backup granularity,
          * we need to advance the iterator pointer to the next cluster. */
         if (granularity < job->cluster_size) {
-            bdrv_set_dirty_iter(dbi,
-                                cluster * job->cluster_size / BDRV_SECTOR_SIZE);
+            bdrv_set_dirty_iter(dbi, cluster * job->cluster_size);
         }

         last_cluster = cluster - 1;
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index a413df1..3fb4871 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -367,11 +367,10 @@ uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap)
     return BDRV_SECTOR_SIZE << hbitmap_granularity(bitmap->bitmap);
 }

-BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
-                                         uint64_t first_sector)
+BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap)
 {
     BdrvDirtyBitmapIter *iter = g_new(BdrvDirtyBitmapIter, 1);
-    hbitmap_iter_init(&iter->hbi, bitmap->bitmap, first_sector);
+    hbitmap_iter_init(&iter->hbi, bitmap->bitmap, 0);
     iter->bitmap = bitmap;
     bitmap->active_iterators++;
     return iter;
@@ -488,9 +487,9 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
 /**
  * Advance a BdrvDirtyBitmapIter to an arbitrary offset.
  */
-void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *iter, int64_t sector_num)
+void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *iter, int64_t offset)
 {
-    hbitmap_iter_init(&iter->hbi, iter->hbi.hb, sector_num);
+    hbitmap_iter_init(&iter->hbi, iter->hbi.hb, offset >> BDRV_SECTOR_BITS);
 }

 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap)
diff --git a/block/mirror.c b/block/mirror.c
index 452d546..885cc29 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -370,7 +370,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
         next_dirty = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE;
         if (next_dirty > next_offset || next_dirty < 0) {
             /* The bitmap iterator's cache is stale, refresh it */
-            bdrv_set_dirty_iter(s->dbi, next_offset >> BDRV_SECTOR_BITS);
+            bdrv_set_dirty_iter(s->dbi, next_offset);
             next_dirty = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE;
         }
         assert(next_dirty == next_offset);
@@ -779,7 +779,7 @@ static void coroutine_fn mirror_run(void *opaque)
     }

     assert(!s->dbi);
-    s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap, 0);
+    s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap);
     for (;;) {
         uint64_t delay_ns = 0;
         int64_t cnt, delta;
-- 
2.9.4

[Qemu-devel] [PATCH v2 06/12] dirty-bitmap: Change bdrv_dirty_iter_next() to report byte offset

[Eric Blake]

Thanks to recent cleanups, all callers were scaling a return value
of sectors into bytes; do the scaling internally instead.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

---
v2: no change
---
 block/backup.c       | 2 +-
 block/dirty-bitmap.c | 2 +-
 block/mirror.c       | 8 ++++----
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/block/backup.c b/block/backup.c
index 70126b8..dc3c7f2 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -375,7 +375,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)
     dbi = bdrv_dirty_iter_new(job->sync_bitmap);

     /* Find the next dirty sector(s) */
-    while ((offset = bdrv_dirty_iter_next(dbi) * BDRV_SECTOR_SIZE) >= 0) {
+    while ((offset = bdrv_dirty_iter_next(dbi)) >= 0) {
         cluster = offset / job->cluster_size;

         /* Fake progress updates for any clusters we skipped */
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 3fb4871..2f9f554 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -397,7 +397,7 @@ void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)

 int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
 {
-    return hbitmap_iter_next(&iter->hbi);
+    return hbitmap_iter_next(&iter->hbi) * BDRV_SECTOR_SIZE;
 }

 void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
diff --git a/block/mirror.c b/block/mirror.c
index 885cc29..8428733 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -335,10 +335,10 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
     bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target));
     int max_io_bytes = MAX(s->buf_size / MAX_IN_FLIGHT, MAX_IO_BYTES);

-    offset = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE;
+    offset = bdrv_dirty_iter_next(s->dbi);
     if (offset < 0) {
         bdrv_set_dirty_iter(s->dbi, 0);
-        offset = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE;
+        offset = bdrv_dirty_iter_next(s->dbi);
         trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap) *
                                   BDRV_SECTOR_SIZE);
         assert(offset >= 0);
@@ -367,11 +367,11 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
             break;
         }

-        next_dirty = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE;
+        next_dirty = bdrv_dirty_iter_next(s->dbi);
         if (next_dirty > next_offset || next_dirty < 0) {
             /* The bitmap iterator's cache is stale, refresh it */
             bdrv_set_dirty_iter(s->dbi, next_offset);
-            next_dirty = bdrv_dirty_iter_next(s->dbi) * BDRV_SECTOR_SIZE;
+            next_dirty = bdrv_dirty_iter_next(s->dbi);
         }
         assert(next_dirty == next_offset);
         nb_chunks++;
-- 
2.9.4

[Qemu-devel] [PATCH v2 07/12] dirty-bitmap: Change bdrv_get_dirty_count() to report bytes

[Eric Blake]

Thanks to recent cleanups, all callers were scaling a return value
of sectors into bytes; do the scaling internally instead.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

---
v2: no change
---
 block/dirty-bitmap.c |  4 ++--
 block/mirror.c       | 13 +++++--------
 migration/block.c    |  2 +-
 3 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 2f9f554..e3c2e34 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -319,7 +319,7 @@ BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
     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) << BDRV_SECTOR_BITS;
+        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);
@@ -494,7 +494,7 @@ void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *iter, int64_t offset)

 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap)
 {
-    return hbitmap_count(bitmap->bitmap);
+    return hbitmap_count(bitmap->bitmap) << BDRV_SECTOR_BITS;
 }

 int64_t bdrv_get_meta_dirty_count(BdrvDirtyBitmap *bitmap)
diff --git a/block/mirror.c b/block/mirror.c
index 8428733..b82bdce 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -794,11 +794,10 @@ static void coroutine_fn mirror_run(void *opaque)

         cnt = bdrv_get_dirty_count(s->dirty_bitmap);
         /* s->common.offset contains the number of bytes already processed so
-         * far, cnt is the number of dirty sectors remaining and
+         * far, cnt is the number of dirty bytes remaining and
          * s->bytes_in_flight is the number of bytes currently being
          * processed; together those are the current total operation length */
-        s->common.len = s->common.offset + s->bytes_in_flight +
-            cnt * BDRV_SECTOR_SIZE;
+        s->common.len = s->common.offset + s->bytes_in_flight + cnt;

         /* Note that even when no rate limit is applied we need to yield
          * periodically with no pending I/O so that bdrv_drain_all() returns.
@@ -810,8 +809,7 @@ static void coroutine_fn mirror_run(void *opaque)
             s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
             if (s->in_flight >= MAX_IN_FLIGHT || s->buf_free_count == 0 ||
                 (cnt == 0 && s->in_flight > 0)) {
-                trace_mirror_yield(s, cnt * BDRV_SECTOR_SIZE,
-                                   s->buf_free_count, s->in_flight);
+                trace_mirror_yield(s, cnt, s->buf_free_count, s->in_flight);
                 mirror_wait_for_io(s);
                 continue;
             } else if (cnt != 0) {
@@ -852,7 +850,7 @@ static void coroutine_fn mirror_run(void *opaque)
              * whether to switch to target check one last time if I/O has
              * come in the meanwhile, and if not flush the data to disk.
              */
-            trace_mirror_before_drain(s, cnt * BDRV_SECTOR_SIZE);
+            trace_mirror_before_drain(s, cnt);

             bdrv_drained_begin(bs);
             cnt = bdrv_get_dirty_count(s->dirty_bitmap);
@@ -871,8 +869,7 @@ static void coroutine_fn mirror_run(void *opaque)
         }

         ret = 0;
-        trace_mirror_before_sleep(s, cnt * BDRV_SECTOR_SIZE,
-                                  s->synced, delay_ns);
+        trace_mirror_before_sleep(s, cnt, s->synced, delay_ns);
         if (!s->synced) {
             block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
             if (block_job_is_cancelled(&s->common)) {
diff --git a/migration/block.c b/migration/block.c
index ecc838a..5a545cf 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -672,7 +672,7 @@ static int64_t get_remaining_dirty(void)
         aio_context_release(blk_get_aio_context(bmds->blk));
     }

-    return dirty << BDRV_SECTOR_BITS;
+    return dirty;
 }

 /* Called with iothread lock taken.  */
-- 
2.9.4

Re: [Qemu-devel] [PATCH v2 07/12] dirty-bitmap: Change bdrv_get_dirty_count() to report bytes

[Juan Quintela]

Eric Blake <eblake@redhat.com> wrote:
> Thanks to recent cleanups, all callers were scaling a return value
> of sectors into bytes; do the scaling internally instead.
>
> Signed-off-by: Eric Blake <eblake@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>
>

Reviewed-by: Juan Quintela <quintela@redhat.com>

[Qemu-devel] [PATCH v2 08/12] dirty-bitmap: Change bdrv_get_dirty() to take bytes

[Eric Blake]

Half the callers were already scaling bytes to sectors; the other
half can eventually be simplified to use byte iteration.  Both
callers were already using the result as a bool, so make that
explicit.  Making the change also makes it easier for a future
dirty-bitmap patch to offload scaling over to the internal hbitmap.

Remember, asking whether a byte is dirty is effectively asking
whether the entire granularity containing the byte is dirty, since
we only track dirtiness by granularity.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

---
v2: tweak commit message, no code change
---
 include/block/dirty-bitmap.h | 4 ++--
 block/dirty-bitmap.c         | 8 ++++----
 block/mirror.c               | 3 +--
 migration/block.c            | 3 +--
 4 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
index efcec60..b8434e5 100644
--- a/include/block/dirty-bitmap.h
+++ b/include/block/dirty-bitmap.h
@@ -34,8 +34,8 @@ bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap);
 bool bdrv_dirty_bitmap_frozen(BdrvDirtyBitmap *bitmap);
 const char *bdrv_dirty_bitmap_name(const BdrvDirtyBitmap *bitmap);
 DirtyBitmapStatus bdrv_dirty_bitmap_status(BdrvDirtyBitmap *bitmap);
-int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
-                   int64_t sector);
+bool bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
+                    int64_t offset);
 void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
                            int64_t cur_sector, int64_t nr_sectors);
 void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index e3c2e34..c8100d2 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -332,13 +332,13 @@ BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
     return list;
 }

-int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
-                   int64_t sector)
+bool bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
+                    int64_t offset)
 {
     if (bitmap) {
-        return hbitmap_get(bitmap->bitmap, sector);
+        return hbitmap_get(bitmap->bitmap, offset >> BDRV_SECTOR_BITS);
     } else {
-        return 0;
+        return false;
     }
 }

diff --git a/block/mirror.c b/block/mirror.c
index b82bdce..8b36ec2 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -359,8 +359,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
         int64_t next_offset = offset + nb_chunks * s->granularity;
         int64_t next_chunk = next_offset / s->granularity;
         if (next_offset >= s->bdev_length ||
-            !bdrv_get_dirty(source, s->dirty_bitmap,
-                            next_offset >> BDRV_SECTOR_BITS)) {
+            !bdrv_get_dirty(source, s->dirty_bitmap, next_offset)) {
             break;
         }
         if (test_bit(next_chunk, s->in_flight_bitmap)) {
diff --git a/migration/block.c b/migration/block.c
index 5a545cf..3e3dec9 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -537,8 +537,7 @@ static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds,
         } else {
             blk_mig_unlock();
         }
-        if (bdrv_get_dirty(bs, bmds->dirty_bitmap, sector)) {
-
+        if (bdrv_get_dirty(bs, bmds->dirty_bitmap, sector * BDRV_SECTOR_SIZE)) {
             if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
                 nr_sectors = total_sectors - sector;
             } else {
-- 
2.9.4

Re: [Qemu-devel] [PATCH v2 08/12] dirty-bitmap: Change bdrv_get_dirty() to take bytes

[Juan Quintela]

Eric Blake <eblake@redhat.com> wrote:
> Half the callers were already scaling bytes to sectors; the other
> half can eventually be simplified to use byte iteration.  Both
> callers were already using the result as a bool, so make that
> explicit.  Making the change also makes it easier for a future
> dirty-bitmap patch to offload scaling over to the internal hbitmap.
>
> Remember, asking whether a byte is dirty is effectively asking
> whether the entire granularity containing the byte is dirty, since
> we only track dirtiness by granularity.
>
> Signed-off-by: Eric Blake <eblake@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>

[Qemu-devel] [PATCH v2 09/12] dirty-bitmap: Change bdrv_[re]set_dirty_bitmap() to use bytes

[Eric Blake]

Some of the callers were already scaling bytes to sectors; others
can be easily converted to pass byte offsets, all in our shift
towards a consistent byte interface everywhere.  Making the change
will also make it easier to write the hold-out callers to use byte
rather than sectors for their iterations; it also makes it easier
for a future dirty-bitmap patch to offload scaling over to the
internal hbitmap.  Although all callers happen to pass
sector-aligned values, make the internal scaling robust to any
sub-sector requests.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

---
v2: no change
---
 include/block/dirty-bitmap.h |  4 ++--
 block/dirty-bitmap.c         | 14 ++++++++++----
 block/mirror.c               | 16 ++++++++--------
 migration/block.c            |  7 +++++--
 4 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
index b8434e5..fdff1e2 100644
--- a/include/block/dirty-bitmap.h
+++ b/include/block/dirty-bitmap.h
@@ -37,9 +37,9 @@ DirtyBitmapStatus bdrv_dirty_bitmap_status(BdrvDirtyBitmap *bitmap);
 bool bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                     int64_t offset);
 void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
-                           int64_t cur_sector, int64_t nr_sectors);
+                           int64_t offset, int64_t bytes);
 void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
-                             int64_t cur_sector, int64_t nr_sectors);
+                             int64_t offset, int64_t bytes);
 BdrvDirtyBitmapIter *bdrv_dirty_meta_iter_new(BdrvDirtyBitmap *bitmap);
 BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap);
 void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter);
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index c8100d2..8e7822c 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -401,17 +401,23 @@ int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
 }

 void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
-                           int64_t cur_sector, int64_t nr_sectors)
+                           int64_t offset, int64_t bytes)
 {
+    int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
+
     assert(bdrv_dirty_bitmap_enabled(bitmap));
-    hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
+    hbitmap_set(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
+                end_sector - (offset >> BDRV_SECTOR_BITS));
 }

 void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
-                             int64_t cur_sector, int64_t nr_sectors)
+                             int64_t offset, int64_t bytes)
 {
+    int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
+
     assert(bdrv_dirty_bitmap_enabled(bitmap));
-    hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
+    hbitmap_reset(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
+                  end_sector - (offset >> BDRV_SECTOR_BITS));
 }

 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)
diff --git a/block/mirror.c b/block/mirror.c
index 8b36ec2..b4fe259 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -141,8 +141,7 @@ static void mirror_write_complete(void *opaque, int ret)
     if (ret < 0) {
         BlockErrorAction action;

-        bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset >> BDRV_SECTOR_BITS,
-                              op->bytes >> BDRV_SECTOR_BITS);
+        bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset, op->bytes);
         action = mirror_error_action(s, false, -ret);
         if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
             s->ret = ret;
@@ -161,8 +160,7 @@ static void mirror_read_complete(void *opaque, int ret)
     if (ret < 0) {
         BlockErrorAction action;

-        bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset >> BDRV_SECTOR_BITS,
-                              op->bytes >> BDRV_SECTOR_BITS);
+        bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset, op->bytes);
         action = mirror_error_action(s, true, -ret);
         if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
             s->ret = ret;
@@ -380,8 +378,8 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
      * calling bdrv_get_block_status_above could yield - if some blocks are
      * marked dirty in this window, we need to know.
      */
-    bdrv_reset_dirty_bitmap(s->dirty_bitmap, offset >> BDRV_SECTOR_BITS,
-                            nb_chunks * sectors_per_chunk);
+    bdrv_reset_dirty_bitmap(s->dirty_bitmap, offset,
+                            nb_chunks * s->granularity);
     bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks);
     while (nb_chunks > 0 && offset < s->bdev_length) {
         int64_t ret;
@@ -614,7 +612,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)

     if (base == NULL && !bdrv_has_zero_init(target_bs)) {
         if (!bdrv_can_write_zeroes_with_unmap(target_bs)) {
-            bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, end);
+            bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, s->bdev_length);
             return 0;
         }

@@ -667,7 +665,9 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
         n = DIV_ROUND_UP(count, BDRV_SECTOR_SIZE);
         assert(n > 0);
         if (ret == 1) {
-            bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n);
+            bdrv_set_dirty_bitmap(s->dirty_bitmap,
+                                  sector_num * BDRV_SECTOR_SIZE,
+                                  n * BDRV_SECTOR_SIZE);
         }
         sector_num += n;
     }
diff --git a/migration/block.c b/migration/block.c
index 3e3dec9..5b1b53c 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -331,7 +331,8 @@ static int mig_save_device_bulk(QEMUFile *f, BlkMigDevState *bmds)
     blk->aiocb = blk_aio_preadv(bb, cur_sector * BDRV_SECTOR_SIZE, &blk->qiov,
                                 0, blk_mig_read_cb, blk);

-    bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, cur_sector, nr_sectors);
+    bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, cur_sector * BDRV_SECTOR_SIZE,
+                            nr_sectors * BDRV_SECTOR_SIZE);
     aio_context_release(blk_get_aio_context(bmds->blk));
     qemu_mutex_unlock_iothread();

@@ -575,7 +576,9 @@ static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds,
                 g_free(blk);
             }

-            bdrv_reset_dirty_bitmap(bmds->dirty_bitmap, sector, nr_sectors);
+            bdrv_reset_dirty_bitmap(bmds->dirty_bitmap,
+                                    sector * BDRV_SECTOR_SIZE,
+                                    nr_sectors * BDRV_SECTOR_SIZE);
             sector += nr_sectors;
             bmds->cur_dirty = sector;

-- 
2.9.4

Re: [Qemu-devel] [PATCH v2 09/12] dirty-bitmap: Change bdrv_[re]set_dirty_bitmap() to use bytes

[Juan Quintela]

Eric Blake <eblake@redhat.com> wrote:
> Some of the callers were already scaling bytes to sectors; others
> can be easily converted to pass byte offsets, all in our shift
> towards a consistent byte interface everywhere.  Making the change
> will also make it easier to write the hold-out callers to use byte
> rather than sectors for their iterations; it also makes it easier
> for a future dirty-bitmap patch to offload scaling over to the
> internal hbitmap.  Although all callers happen to pass
> sector-aligned values, make the internal scaling robust to any
> sub-sector requests.
>
> Signed-off-by: Eric Blake <eblake@redhat.com>
> Reviewed-by: John Snow <jsnow@redhat.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>


> +
>      assert(bdrv_dirty_bitmap_enabled(bitmap));
> -    hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
> +    hbitmap_set(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
> +                end_sector - (offset >> BDRV_SECTOR_BITS));

It is just me, or we use:

bytes = sectors * BDRV_SECTOR_SIZE
or
bytes = sectors << BDRV_SECTOR_BITS

and the same from bytes to sectors (no, this patch is consistent,
but just looking at the file ....)

Later, Juan.

Re: [Qemu-devel] [PATCH v2 09/12] dirty-bitmap: Change bdrv_[re]set_dirty_bitmap() to use bytes

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 2329 bytes --]

On 05/17/2017 06:59 AM, Juan Quintela wrote:
> Eric Blake <eblake@redhat.com> wrote:
>> Some of the callers were already scaling bytes to sectors; others
>> can be easily converted to pass byte offsets, all in our shift
>> towards a consistent byte interface everywhere.  Making the change
>> will also make it easier to write the hold-out callers to use byte
>> rather than sectors for their iterations; it also makes it easier
>> for a future dirty-bitmap patch to offload scaling over to the
>> internal hbitmap.  Although all callers happen to pass
>> sector-aligned values, make the internal scaling robust to any
>> sub-sector requests.
>>
>> Signed-off-by: Eric Blake <eblake@redhat.com>
>> Reviewed-by: John Snow <jsnow@redhat.com>
> 
> Reviewed-by: Juan Quintela <quintela@redhat.com>
> 
> 
>> +
>>      assert(bdrv_dirty_bitmap_enabled(bitmap));
>> -    hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
>> +    hbitmap_set(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
>> +                end_sector - (offset >> BDRV_SECTOR_BITS));
> 
> It is just me, or we use:
> 
> bytes = sectors * BDRV_SECTOR_SIZE
> or
> bytes = sectors << BDRV_SECTOR_BITS

BDRV_SECTOR_SIZE is ULL, while BDRV_SECTOR_BITS is not. Multiplying by
SIZE guarantees a 64-bit answer, but shifting by bits will give only a
32-bit answer if the left hand side of << is not already 64 bits (I've
had bugs in earlier conversion patches where I used << but should have
used *).  So for scaling up, my recent round of patches have been
favoring * (ideally, since BDRV_SECTOR_SIZE is a power-of-2 constant,
the compiler optimizes it into a shift anyways instead of wasting time
on a multiply).

For scaling down, '/ SIZE' and '>> BITS' are equivalent, but I prefer
the >> form.

> 
> and the same from bytes to sectors (no, this patch is consistent,
> but just looking at the file ....)

The real end-goal is to update the file to track the entire process with
bytes everywhere (and skip the intermediate representation in sectors),
which will reduce the number of scaling operations needed in the first
place.  migration/block.c isn't quite there yet, but we'll get there.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 604 bytes --]

[Qemu-devel] [PATCH v2 10/12] mirror: Switch mirror_dirty_init() to byte-based iteration

[Eric Blake]

Now that we have adjusted the majority of the calls this function
makes to be byte-based, it is easier to read the code if it makes
passes over the image using bytes rather than sectors.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

---
v2: no change
---
 block/mirror.c | 35 ++++++++++++++---------------------
 1 file changed, 14 insertions(+), 21 deletions(-)

diff --git a/block/mirror.c b/block/mirror.c
index b4fe259..6cfa57c 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -601,15 +601,13 @@ static void mirror_throttle(MirrorBlockJob *s)

 static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
 {
-    int64_t sector_num, end;
+    int64_t offset;
     BlockDriverState *base = s->base;
     BlockDriverState *bs = s->source;
     BlockDriverState *target_bs = blk_bs(s->target);
-    int ret, n;
+    int ret;
     int64_t count;

-    end = s->bdev_length / BDRV_SECTOR_SIZE;
-
     if (base == NULL && !bdrv_has_zero_init(target_bs)) {
         if (!bdrv_can_write_zeroes_with_unmap(target_bs)) {
             bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, s->bdev_length);
@@ -617,9 +615,9 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
         }

         s->initial_zeroing_ongoing = true;
-        for (sector_num = 0; sector_num < end; ) {
-            int nb_sectors = MIN(end - sector_num,
-                QEMU_ALIGN_DOWN(INT_MAX, s->granularity) >> BDRV_SECTOR_BITS);
+        for (offset = 0; offset < s->bdev_length; ) {
+            int bytes = MIN(s->bdev_length - offset,
+                            QEMU_ALIGN_DOWN(INT_MAX, s->granularity));

             mirror_throttle(s);

@@ -635,9 +633,8 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
                 continue;
             }

-            mirror_do_zero_or_discard(s, sector_num * BDRV_SECTOR_SIZE,
-                                      nb_sectors * BDRV_SECTOR_SIZE, false);
-            sector_num += nb_sectors;
+            mirror_do_zero_or_discard(s, offset, bytes, false);
+            offset += bytes;
         }

         mirror_wait_for_all_io(s);
@@ -645,10 +642,10 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
     }

     /* First part, loop on the sectors and initialize the dirty bitmap.  */
-    for (sector_num = 0; sector_num < end; ) {
+    for (offset = 0; offset < s->bdev_length; ) {
         /* Just to make sure we are not exceeding int limit. */
-        int nb_sectors = MIN(INT_MAX >> BDRV_SECTOR_BITS,
-                             end - sector_num);
+        int bytes = MIN(s->bdev_length - offset,
+                        QEMU_ALIGN_DOWN(INT_MAX, s->granularity));

         mirror_throttle(s);

@@ -656,20 +653,16 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
             return 0;
         }

-        ret = bdrv_is_allocated_above(bs, base, sector_num * BDRV_SECTOR_SIZE,
-                                      nb_sectors * BDRV_SECTOR_SIZE, &count);
+        ret = bdrv_is_allocated_above(bs, base, offset, bytes, &count);
         if (ret < 0) {
             return ret;
         }

-        n = DIV_ROUND_UP(count, BDRV_SECTOR_SIZE);
-        assert(n > 0);
+        count = QEMU_ALIGN_UP(count, BDRV_SECTOR_SIZE);
         if (ret == 1) {
-            bdrv_set_dirty_bitmap(s->dirty_bitmap,
-                                  sector_num * BDRV_SECTOR_SIZE,
-                                  n * BDRV_SECTOR_SIZE);
+            bdrv_set_dirty_bitmap(s->dirty_bitmap, offset, count);
         }
-        sector_num += n;
+        offset += count;
     }
     return 0;
 }
-- 
2.9.4

[Qemu-devel] [PATCH v2 11/12] dirty-bitmap: Switch bdrv_set_dirty() to bytes

[Eric Blake]

Both callers already had bytes available, but were scaling to
sectors.  Move the scaling to internal code.  In the case of
bdrv_aligned_pwritev(), we are now passing the exact offset
rather than a rounded sector-aligned value, but that's okay
as long as dirty bitmap widens start/bytes to granularity
boundaries.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

---
v2: no change
---
 include/block/block_int.h | 2 +-
 block/dirty-bitmap.c      | 8 +++++---
 block/io.c                | 6 ++----
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 8d3724c..eec9835 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -931,7 +931,7 @@ void blk_dev_eject_request(BlockBackend *blk, bool force);
 bool blk_dev_is_tray_open(BlockBackend *blk);
 bool blk_dev_is_medium_locked(BlockBackend *blk);

-void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector, int64_t nr_sect);
+void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes);
 bool bdrv_requests_pending(BlockDriverState *bs);

 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out);
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 8e7822c..ef165eb 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -478,15 +478,17 @@ void bdrv_dirty_bitmap_deserialize_finish(BdrvDirtyBitmap *bitmap)
     hbitmap_deserialize_finish(bitmap->bitmap);
 }

-void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
-                    int64_t nr_sectors)
+void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes)
 {
     BdrvDirtyBitmap *bitmap;
+    int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
+
     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
         if (!bdrv_dirty_bitmap_enabled(bitmap)) {
             continue;
         }
-        hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
+        hbitmap_set(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
+                    end_sector - (offset >> BDRV_SECTOR_BITS));
     }
 }

diff --git a/block/io.c b/block/io.c
index d4f1925..e86a546 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1324,7 +1324,6 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
     bool waited;
     int ret;

-    int64_t start_sector = offset >> BDRV_SECTOR_BITS;
     int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
     uint64_t bytes_remaining = bytes;
     int max_transfer;
@@ -1395,7 +1394,7 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
     bdrv_debug_event(bs, BLKDBG_PWRITEV_DONE);

     ++bs->write_gen;
-    bdrv_set_dirty(bs, start_sector, end_sector - start_sector);
+    bdrv_set_dirty(bs, offset, bytes);

     if (bs->wr_highest_offset < offset + bytes) {
         bs->wr_highest_offset = offset + bytes;
@@ -2529,8 +2528,7 @@ int coroutine_fn bdrv_co_pdiscard(BlockDriverState *bs, int64_t offset,
     ret = 0;
 out:
     ++bs->write_gen;
-    bdrv_set_dirty(bs, req.offset >> BDRV_SECTOR_BITS,
-                   req.bytes >> BDRV_SECTOR_BITS);
+    bdrv_set_dirty(bs, req.offset, req.bytes);
     tracked_request_end(&req);
     bdrv_dec_in_flight(bs);
     return ret;
-- 
2.9.4

[Qemu-devel] [PATCH v2 12/12] dirty-bitmap: Convert internal hbitmap size/granularity

[Eric Blake]

Now that all callers are using byte-based interfaces, there's no
reason for our internal hbitmap to remain with sector-based
granularity.  It also simplifies our internal scaling, since we
already know that hbitmap widens requests out to granularity
boundaries.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>

---
v2: no change
---
 block/dirty-bitmap.c | 37 ++++++++++++-------------------------
 1 file changed, 12 insertions(+), 25 deletions(-)

diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index ef165eb..26ca084 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -37,7 +37,7 @@
  *     or enabled. A frozen bitmap can only abdicate() or reclaim().
  */
 struct BdrvDirtyBitmap {
-    HBitmap *bitmap;            /* Dirty sector bitmap implementation */
+    HBitmap *bitmap;            /* Dirty bitmap implementation */
     HBitmap *meta;              /* Meta dirty bitmap */
     BdrvDirtyBitmap *successor; /* Anonymous child; implies frozen status */
     char *name;                 /* Optional non-empty unique ID */
@@ -93,12 +93,7 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
         return NULL;
     }
     bitmap = g_new0(BdrvDirtyBitmap, 1);
-    /*
-     * TODO - let hbitmap track full granularity. For now, it is tracking
-     * only sector granularity, as a shortcut for our iterators.
-     */
-    bitmap->bitmap = hbitmap_alloc(bitmap_size >> BDRV_SECTOR_BITS,
-                                   ctz32(granularity) - BDRV_SECTOR_BITS);
+    bitmap->bitmap = hbitmap_alloc(bitmap_size, ctz32(granularity));
     bitmap->size = bitmap_size;
     bitmap->name = g_strdup(name);
     bitmap->disabled = false;
@@ -254,7 +249,7 @@ void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
         assert(!bdrv_dirty_bitmap_frozen(bitmap));
         assert(!bitmap->active_iterators);
-        hbitmap_truncate(bitmap->bitmap, size >> BDRV_SECTOR_BITS);
+        hbitmap_truncate(bitmap->bitmap, size);
         bitmap->size = size;
     }
 }
@@ -336,7 +331,7 @@ bool bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                     int64_t offset)
 {
     if (bitmap) {
-        return hbitmap_get(bitmap->bitmap, offset >> BDRV_SECTOR_BITS);
+        return hbitmap_get(bitmap->bitmap, offset);
     } else {
         return false;
     }
@@ -364,7 +359,7 @@ uint32_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs)

 uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap)
 {
-    return BDRV_SECTOR_SIZE << hbitmap_granularity(bitmap->bitmap);
+    return 1U << hbitmap_granularity(bitmap->bitmap);
 }

 BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap)
@@ -397,27 +392,21 @@ void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)

 int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
 {
-    return hbitmap_iter_next(&iter->hbi) * BDRV_SECTOR_SIZE;
+    return hbitmap_iter_next(&iter->hbi);
 }

 void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
                            int64_t offset, int64_t bytes)
 {
-    int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
-
     assert(bdrv_dirty_bitmap_enabled(bitmap));
-    hbitmap_set(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
-                end_sector - (offset >> BDRV_SECTOR_BITS));
+    hbitmap_set(bitmap->bitmap, offset, bytes);
 }

 void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
                              int64_t offset, int64_t bytes)
 {
-    int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
-
     assert(bdrv_dirty_bitmap_enabled(bitmap));
-    hbitmap_reset(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
-                  end_sector - (offset >> BDRV_SECTOR_BITS));
+    hbitmap_reset(bitmap->bitmap, offset, bytes);
 }

 void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)
@@ -427,7 +416,7 @@ void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)
         hbitmap_reset_all(bitmap->bitmap);
     } else {
         HBitmap *backup = bitmap->bitmap;
-        bitmap->bitmap = hbitmap_alloc(bitmap->size >> BDRV_SECTOR_BITS,
+        bitmap->bitmap = hbitmap_alloc(bitmap->size,
                                        hbitmap_granularity(backup));
         *out = backup;
     }
@@ -481,14 +470,12 @@ void bdrv_dirty_bitmap_deserialize_finish(BdrvDirtyBitmap *bitmap)
 void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes)
 {
     BdrvDirtyBitmap *bitmap;
-    int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);

     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
         if (!bdrv_dirty_bitmap_enabled(bitmap)) {
             continue;
         }
-        hbitmap_set(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
-                    end_sector - (offset >> BDRV_SECTOR_BITS));
+        hbitmap_set(bitmap->bitmap, offset, bytes);
     }
 }

@@ -497,12 +484,12 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes)
  */
 void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *iter, int64_t offset)
 {
-    hbitmap_iter_init(&iter->hbi, iter->hbi.hb, offset >> BDRV_SECTOR_BITS);
+    hbitmap_iter_init(&iter->hbi, iter->hbi.hb, offset);
 }

 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap)
 {
-    return hbitmap_count(bitmap->bitmap) << BDRV_SECTOR_BITS;
+    return hbitmap_count(bitmap->bitmap);
 }

 int64_t bdrv_get_meta_dirty_count(BdrvDirtyBitmap *bitmap)
-- 
2.9.4