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make dirty-bitmap byte-based

PATCH Superseded Eric Blake 2 participants 29 messages Sep 12, 2017 – Sep 14, 2017 Block layer

v7 of 10 Superseded Latest is v10 →

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Eric Blake

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#0 lore raw

v7 cover make dirty-bitmap byte-based

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.

Now that 2.11 is open, I'm rebasing/reposting the remaining patches.

The overall conversion currently looks like:
part 1: bdrv_is_allocated (merged in 2.10, commit 51b0a488) part 2: dirty-bitmap (this series, v6 was here [1])
part 3: bdrv_get_block_status (v3 is posted [2] and is mostly reviewed, but needs a rebase)
part 4: .bdrv_co_block_status (v2 is posted [3], but needs a rebase)

Available as a tag at:
git fetch git://repo.or.cz/qemu/ericb.git nbd-byte-dirty-v7

[1] https://lists.gnu.org/archive/html/qemu-devel/2017-08/msg06247.html
[2] https://lists.gnu.org/archive/html/qemu-devel/2017-07/msg03853.html
[3] https://lists.gnu.org/archive/html/qemu-devel/2017-07/msg04370.html

Diff from v6:
- split v6 patch 5/18 into 3 parts in 5-7/20 [Kevin]
- improve bdrv_dirty_iter_next() interface in 11/20 [Kevin]
- fix missing trace conversion in 12/20 [Kevin]
- stricter conversions in 16/20, 18/20 [Kevin]
- rebase to above in 20/20

001/20:[----] [--] 'block: Make bdrv_img_create() size selection easier to read' 002/20:[----] [--] 'hbitmap: Rename serialization_granularity to serialization_align' 003/20:[----] [--] 'qcow2: Ensure bitmap serialization is aligned' 004/20:[----] [--] 'dirty-bitmap: Drop unused functions'
005/20:[down] 'dirty-bitmap: Check for size query failure during truncate' 006/20:[0028] [FC] 'dirty-bitmap: Change bdrv_dirty_bitmap_size() to report bytes' 007/20:[down] 'dirty-bitmap: Track bitmap size by bytes'
008/20:[----] [--] 'dirty-bitmap: Change bdrv_dirty_bitmap_*serialize*() to take bytes' 009/20:[----] [--] 'qcow2: Switch sectors_covered_by_bitmap_cluster() to byte-based' 010/20:[----] [-C] 'dirty-bitmap: Set iterator start by offset, not sector' 011/20:[0005] [FC] 'dirty-bitmap: Change bdrv_dirty_iter_next() to report byte offset' 012/20:[0003] [FC] 'dirty-bitmap: Change bdrv_get_dirty_count() to report bytes' 013/20:[----] [--] 'dirty-bitmap: Change bdrv_get_dirty_locked() to take bytes' 014/20:[----] [--] 'dirty-bitmap: Change bdrv_[re]set_dirty_bitmap() to use bytes' 015/20:[----] [--] 'mirror: Switch mirror_dirty_init() to byte-based iteration' 016/20:[0002] [FC] 'qcow2: Switch qcow2_measure() to byte-based iteration' 017/20:[----] [--] 'qcow2: Switch load_bitmap_data() to byte-based iteration' 018/20:[0006] [FC] 'qcow2: Switch store_bitmap_data() to byte-based iteration' 019/20:[----] [--] 'dirty-bitmap: Switch bdrv_set_dirty() to bytes' 020/20:[0003] [FC] 'dirty-bitmap: Convert internal hbitmap size/granularity'

Eric Blake (20):
block: Make bdrv_img_create() size selection easier to read
hbitmap: Rename serialization_granularity to serialization_align
qcow2: Ensure bitmap serialization is aligned
dirty-bitmap: Drop unused functions
dirty-bitmap: Check for size query failure during truncate
dirty-bitmap: Change bdrv_dirty_bitmap_size() to report bytes
dirty-bitmap: Track bitmap size by bytes
dirty-bitmap: Change bdrv_dirty_bitmap_*serialize*() to take bytes
qcow2: Switch sectors_covered_by_bitmap_cluster() to byte-based
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_locked() to take bytes
dirty-bitmap: Change bdrv_[re]set_dirty_bitmap() to use bytes
mirror: Switch mirror_dirty_init() to byte-based iteration
qcow2: Switch qcow2_measure() to byte-based iteration
qcow2: Switch load_bitmap_data() to byte-based iteration
qcow2: Switch store_bitmap_data() 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 |  43 +++++---------
 include/qemu/hbitmap.h       |   8 +--
 block/io.c                   |   6 +-
 block.c                      |  21 +++++--
 block/backup.c               |   7 +--
 block/dirty-bitmap.c         | 137 +++++++++++++++----------------------------
 block/mirror.c               |  79 ++++++++++---------------
 block/qcow2-bitmap.c         |  57 +++++++++---------
 block/qcow2.c                |  22 ++++---
 migration/block.c            |  12 ++--
 tests/test-hbitmap.c         |  10 ++--
 util/hbitmap.c               |   8 +--
 13 files changed, 175 insertions(+), 237 deletions(-)
Signature · 1 line
2.13.5
author
#1 lore raw

PATCH v7 1/20 block: Make bdrv_img_create() size selection easier to read

All callers of bdrv_img_create() pass in a size, or -1 to read the size from the backing file. We then set that size as the QemuOpt default, which means we will reuse that default rather than the final parameter to qemu_opt_get_size() several lines later. But it is rather confusing to read subsequent checks of 'size == -1' when it looks (without seeing the full context) like size defaults to 0; it also doesn't help that a size of 0 is valid (for some formats).

Rework the logic to make things more legible.

---
v6: Combine into a series rather than being a standalone patch (more for ease of tracking than for being on topic)

---
 block.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
block.c +1 -1
index 6dd47e414e..ee6a48976e 100644
@@ -4393,7 +4393,7 @@ void bdrv_img_create(const char *filename, const char *fmt,
 
     /* The size for the image must always be specified, unless we have a backing
      * file and we have not been forbidden from opening it. */
-    size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
+    size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, img_size);
     if (backing_file && !(flags & BDRV_O_NO_BACKING)) {
         BlockDriverState *bs;
         char *full_backing = g_new0(char, PATH_MAX);
Signature · 1 line
2.13.5
author
#2 lore raw

PATCH v7 2/20 hbitmap: Rename serialization_granularity to serialization_align

In reply to Eric Blake

The only client of hbitmap_serialization_granularity() is dirty-bitmap's bdrv_dirty_bitmap_serialization_align(). Keeping the two names consistent is worthwhile, and the shorter name is more representative of what the function returns (the required alignment to be used for start/count of other serialization functions, where violating the alignment causes assertion failures).

---
v5: no change
v4: new patch

---
 include/qemu/hbitmap.h |  8 ++++----
 block/dirty-bitmap.c   |  2 +-
 tests/test-hbitmap.c   | 10 +++++-----
 util/hbitmap.c         |  8 ++++----
 4 files changed, 14 insertions(+), 14 deletions(-)
include/qemu/hbitmap.h +4 -4
index d3a74a21fc..81e78043d1 100644
@@ -159,16 +159,16 @@ bool hbitmap_get(const HBitmap *hb, uint64_t item);
 bool hbitmap_is_serializable(const HBitmap *hb);
 
 /**
- * hbitmap_serialization_granularity:
+ * hbitmap_serialization_align:
  * @hb: HBitmap to operate on.
  *
- * Granularity of serialization chunks, used by other serialization functions.
- * For every chunk:
+ * Required alignment of serialization chunks, used by other serialization
+ * functions. For every chunk:
  * 1. Chunk start should be aligned to this granularity.
  * 2. Chunk size should be aligned too, except for last chunk (for which
  *      start + count == hb->size)
  */
-uint64_t hbitmap_serialization_granularity(const HBitmap *hb);
+uint64_t hbitmap_serialization_align(const HBitmap *hb);
 
 /**
  * hbitmap_serialization_size:
block/dirty-bitmap.c +1 -1
index 30462d4f9a..0490ca3aff 100644
@@ -617,7 +617,7 @@ uint64_t bdrv_dirty_bitmap_serialization_size(const BdrvDirtyBitmap *bitmap,
 
 uint64_t bdrv_dirty_bitmap_serialization_align(const BdrvDirtyBitmap *bitmap)
 {
-    return hbitmap_serialization_granularity(bitmap->bitmap);
+    return hbitmap_serialization_align(bitmap->bitmap);
 }
 
 void bdrv_dirty_bitmap_serialize_part(const BdrvDirtyBitmap *bitmap,
tests/test-hbitmap.c +5 -5
index 1acb353889..af41642346 100644
@@ -738,15 +738,15 @@ static void test_hbitmap_meta_one(TestHBitmapData *data, const void *unused)
     }
 }
 
-static void test_hbitmap_serialize_granularity(TestHBitmapData *data,
-                                               const void *unused)
+static void test_hbitmap_serialize_align(TestHBitmapData *data,
+                                         const void *unused)
 {
     int r;
 
     hbitmap_test_init(data, L3 * 2, 3);
     g_assert(hbitmap_is_serializable(data->hb));
 
-    r = hbitmap_serialization_granularity(data->hb);
+    r = hbitmap_serialization_align(data->hb);
     g_assert_cmpint(r, ==, 64 << 3);
 }
 
@@ -974,8 +974,8 @@ int main(int argc, char **argv)
     hbitmap_test_add("/hbitmap/meta/word", test_hbitmap_meta_word);
     hbitmap_test_add("/hbitmap/meta/sector", test_hbitmap_meta_sector);
 
-    hbitmap_test_add("/hbitmap/serialize/granularity",
-                     test_hbitmap_serialize_granularity);
+    hbitmap_test_add("/hbitmap/serialize/align",
+                     test_hbitmap_serialize_align);
     hbitmap_test_add("/hbitmap/serialize/basic",
                      test_hbitmap_serialize_basic);
     hbitmap_test_add("/hbitmap/serialize/part",
util/hbitmap.c +4 -4
index 21535cc90b..2f9d0fdbd0 100644
@@ -413,14 +413,14 @@ bool hbitmap_is_serializable(const HBitmap *hb)
 {
     /* Every serialized chunk must be aligned to 64 bits so that endianness
      * requirements can be fulfilled on both 64 bit and 32 bit hosts.
-     * We have hbitmap_serialization_granularity() which converts this
+     * We have hbitmap_serialization_align() which converts this
      * alignment requirement from bitmap bits to items covered (e.g. sectors).
      * That value is:
      *    64 << hb->granularity
      * Since this value must not exceed UINT64_MAX, hb->granularity must be
      * less than 58 (== 64 - 6, where 6 is ld(64), i.e. 1 << 6 == 64).
      *
-     * In order for hbitmap_serialization_granularity() to always return a
+     * In order for hbitmap_serialization_align() to always return a
      * meaningful value, bitmaps that are to be serialized must have a
      * granularity of less than 58. */
 
@@ -437,7 +437,7 @@ bool hbitmap_get(const HBitmap *hb, uint64_t item)
     return (hb->levels[HBITMAP_LEVELS - 1][pos >> BITS_PER_LEVEL] & bit) != 0;
 }
 
-uint64_t hbitmap_serialization_granularity(const HBitmap *hb)
+uint64_t hbitmap_serialization_align(const HBitmap *hb)
 {
     assert(hbitmap_is_serializable(hb));
 
@@ -454,7 +454,7 @@ static void serialization_chunk(const HBitmap *hb,
                                 unsigned long **first_el, uint64_t *el_count)
 {
     uint64_t last = start + count - 1;
-    uint64_t gran = hbitmap_serialization_granularity(hb);
+    uint64_t gran = hbitmap_serialization_align(hb);
 
     assert((start & (gran - 1)) == 0);
     assert((last >> hb->granularity) < hb->size);
Signature · 1 line
2.13.5
author
#3 lore raw

PATCH v7 3/20 qcow2: Ensure bitmap serialization is aligned

In reply to Eric Blake

When subdividing a bitmap serialization, the code in hbitmap.c enforces that start/count parameters are aligned (except that count can end early at end-of-bitmap). We exposed this required alignment through bdrv_dirty_bitmap_serialization_align(), but forgot to actually check that we comply with it.

Fortunately, qcow2 is never dividing bitmap serialization smaller than one cluster (which is a minimum of 512 bytes); so we are always compliant with the serialization alignment (which insists that we partition at least 64 bits per chunk) because we are doing at least 4k bits per chunk.

Still, it's safer to add an assertion (for the unlikely case that we'd ever support a cluster smaller than 512 bytes, or if the hbitmap implementation changes what it considers to be aligned), rather than leaving bdrv_dirty_bitmap_serialization_align() without a caller.

---
v5: no change
v4: new patch

---
 block/qcow2-bitmap.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
block/qcow2-bitmap.c +5 -2
index e8d3bdbd6e..b3ee4c794a 100644
@@ -274,10 +274,13 @@ static int free_bitmap_clusters(BlockDriverState *bs, Qcow2BitmapTable *tb)
 static uint64_t sectors_covered_by_bitmap_cluster(const BDRVQcow2State *s,
                                                   const BdrvDirtyBitmap *bitmap)
 {
-    uint32_t sector_granularity =
+    uint64_t sector_granularity =
             bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS;
+    uint64_t sbc = sector_granularity * (s->cluster_size << 3);
 
-    return (uint64_t)sector_granularity * (s->cluster_size << 3);
+    assert(QEMU_IS_ALIGNED(sbc,
+                           bdrv_dirty_bitmap_serialization_align(bitmap)));
+    return sbc;
 }
 
 /* load_bitmap_data
Signature · 1 line
2.13.5
author
#4 lore raw

PATCH v7 4/20 dirty-bitmap: Drop unused functions

In reply to 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_get_meta
bdrv_dirty_bitmap_get_meta_locked
bdrv_dirty_bitmap_reset_meta
bdrv_dirty_bitmap_meta_granularity

---
v5: no change
v4: rebase to Vladimir's persistent bitmaps (bdrv_dirty_bitmap_size now in use), dropped R-b
v3: rebase to upstream changes (bdrv_dirty_bitmap_get_meta_locked was added in b64bd51e with no clients), kept R-b
v2: tweak commit message based on review, no code change

---
 include/block/dirty-bitmap.h | 10 ----------
 block/dirty-bitmap.c         | 44 --------------------------------------------
 2 files changed, 54 deletions(-)
include/block/dirty-bitmap.h +0 -10
index a79a58d2c3..8fd842eac9 100644
@@ -34,7 +34,6 @@ 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(const 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);
@@ -44,15 +43,6 @@ 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);
-int bdrv_dirty_bitmap_get_meta_locked(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);
block/dirty-bitmap.c +0 -44

56 lines not on this page · raw message

Signature · 1 line
2.13.5
author
#5 lore raw

PATCH v7 5/20 dirty-bitmap: Check for size query failure during truncate

In reply to Eric Blake

We've previously fixed several places where we failed to account for possible errors from bdrv_nb_sectors(). Fix another one by making bdrv_dirty_bitmap_truncate() report the error rather then silently resizing bitmaps to -1. Then adjust the sole caller bdrv_truncate() to both reduce the likelihood of failure (blindly calling bdrv_dirty_bitmap_truncate() after refresh_total_sectors() fails was not nice) as well as propagate any actual failures.

---
v7: new patch [Kevin]

---
 include/block/dirty-bitmap.h |  2 +-
 block.c                      | 19 ++++++++++++++-----
 block/dirty-bitmap.c         | 12 ++++++++----
 3 files changed, 23 insertions(+), 10 deletions(-)
include/block/dirty-bitmap.h +1 -1
index 8fd842eac9..15101b59d5 100644
@@ -83,7 +83,7 @@ int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter);
 void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t sector_num);
 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
 int64_t bdrv_get_meta_dirty_count(BdrvDirtyBitmap *bitmap);
-void bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
+int bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
 bool bdrv_dirty_bitmap_readonly(const BdrvDirtyBitmap *bitmap);
 bool bdrv_has_readonly_bitmaps(BlockDriverState *bs);
 bool bdrv_dirty_bitmap_get_autoload(const BdrvDirtyBitmap *bitmap);
block.c +14 -5
index ee6a48976e..790dcce360 100644
@@ -3450,12 +3450,21 @@ int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc,
     assert(!(bs->open_flags & BDRV_O_INACTIVE));
 
     ret = drv->bdrv_truncate(bs, offset, prealloc, errp);
-    if (ret == 0) {
-        ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
-        bdrv_dirty_bitmap_truncate(bs);
-        bdrv_parent_cb_resize(bs);
-        atomic_inc(&bs->write_gen);
+    if (ret < 0) {
+        return ret;
     }
+    ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "Could not refresh total sector count");
+        return ret;
+    }
+    ret = bdrv_dirty_bitmap_truncate(bs);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "Could not refresh total sector count");
+        return ret;
+    }
+    bdrv_parent_cb_resize(bs);
+    atomic_inc(&bs->write_gen);
     return ret;
 }
 
block/dirty-bitmap.c +8 -4
index 42a55e4a4b..52f7a399b2 100644
@@ -1,7 +1,7 @@
 /*
  * Block Dirty Bitmap
  *
- * Copyright (c) 2016 Red Hat. Inc
+ * Copyright (c) 2016-2017 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
@@ -300,13 +300,16 @@ BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap(BlockDriverState *bs,
 
 /**
  * Truncates _all_ bitmaps attached to a BDS.
- * Called with BQL taken.
+ * Called with BQL taken, returns -errno on failure.
  */
-void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
+int bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
 {
     BdrvDirtyBitmap *bitmap;
-    uint64_t size = bdrv_nb_sectors(bs);
+    int64_t size = bdrv_nb_sectors(bs);
 
+    if (size < 0) {
+        return size;
+    }
     bdrv_dirty_bitmaps_lock(bs);
     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
         assert(!bdrv_dirty_bitmap_frozen(bitmap));
@@ -315,6 +318,7 @@ void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
         bitmap->size = size;
     }
     bdrv_dirty_bitmaps_unlock(bs);
+    return 0;
 }
 
 static bool bdrv_dirty_bitmap_has_name(BdrvDirtyBitmap *bitmap)
Signature · 1 line
2.13.5
#6 lore raw

Re: [Qemu-devel] [PATCH v7 05/20] dirty-bitmap: Check for size query failure during truncate

Quoted 4 lines · Eric Blake

We've previously fixed several places where we failed to account for possible errors from bdrv_nb_sectors(). Fix another one by making bdrv_dirty_bitmap_truncate() report the error rather then silently resizing bitmaps to -1. Then adjust the sole caller

Nice failure mode. It was not immediately obvious to me that this could fail, but here we all are.

Quoted 41 lines

bdrv_truncate() to both reduce the likelihood of failure (blindly calling bdrv_dirty_bitmap_truncate() after refresh_total_sectors() fails was not nice) as well as propagate any actual failures.

---
v7: new patch [Kevin]

---
 include/block/dirty-bitmap.h |  2 +-
 block.c                      | 19 ++++++++++++++-----
 block/dirty-bitmap.c         | 12 ++++++++----
 3 files changed, 23 insertions(+), 10 deletions(-)
include/block/dirty-bitmap.h +1 -1
index 8fd842eac9..15101b59d5 100644
@@ -83,7 +83,7 @@ int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter);
 void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t sector_num);
 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
 int64_t bdrv_get_meta_dirty_count(BdrvDirtyBitmap *bitmap);
-void bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
+int bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
 bool bdrv_dirty_bitmap_readonly(const BdrvDirtyBitmap *bitmap);
 bool bdrv_has_readonly_bitmaps(BlockDriverState *bs);
 bool bdrv_dirty_bitmap_get_autoload(const BdrvDirtyBitmap *bitmap);
block.c +1 -5
index ee6a48976e..790dcce360 100644
@@ -3450,12 +3450,21 @@ int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc,
     assert(!(bs->open_flags & BDRV_O_INACTIVE));
 
     ret = drv->bdrv_truncate(bs, offset, prealloc, errp);
-    if (ret == 0) {
-        ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
-        bdrv_dirty_bitmap_truncate(bs);
-        bdrv_parent_cb_resize(bs);
-        atomic_inc(&bs->write_gen);
+    if (ret < 0) {

block.c int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc, · line 3463

Quoted 10 lines
block.c +9 -0
+        return ret;
     }
+    ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "Could not refresh total sector count");
+        return ret;
+    }
+    ret = bdrv_dirty_bitmap_truncate(bs);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "Could not refresh total sector count");

You probably meant to write a different error message here.

Also, what happens if the actual truncate call works, but the bitmap resizing fails? What state does that leave us in?

author
#7 lore raw

Re: [Qemu-devel] [PATCH v7 05/20] dirty-bitmap: Check for size query failure during truncate

Quoted 36 lines · John Snow
Quoted 4 lines · Eric Blake

We've previously fixed several places where we failed to account for possible errors from bdrv_nb_sectors(). Fix another one by making bdrv_dirty_bitmap_truncate() report the error rather then silently resizing bitmaps to -1. Then adjust the sole caller

Nice failure mode. It was not immediately obvious to me that this could fail, but here we all are.

Quoted 14 lines

bdrv_truncate() to both reduce the likelihood of failure (blindly calling bdrv_dirty_bitmap_truncate() after refresh_total_sectors() fails was not nice) as well as propagate any actual failures.

     ret = drv->bdrv_truncate(bs, offset, prealloc, errp);
block.c +1 -5
-    if (ret == 0) {
-        ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
-        bdrv_dirty_bitmap_truncate(bs);
-        bdrv_parent_cb_resize(bs);
-        atomic_inc(&bs->write_gen);
+    if (ret < 0) {

block.c int bdrv_truncate(BdrvChild *child, int64_t offset, PreallocMode prealloc, · line 3463

Quoted 10 lines
block.c +9 -0
+        return ret;
     }
+    ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "Could not refresh total sector count");
+        return ret;
+    }
+    ret = bdrv_dirty_bitmap_truncate(bs);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "Could not refresh total sector count");
Quoted 4 lines

You probably meant to write a different error message here.

Also, what happens if the actual truncate call works, but the bitmap resizing fails? What state does that leave us in?

Another option: bdrv_dirty_bitmap_truncate() can only fail if bdrv_nb_sectors() can fail. We WANT to use the actual size of the device (which might be slightly different than the requested size passed to bdrv_truncate in the first place), but we could change bdrv_dirty_bitmap_truncate() to take an actual size as a parameter instead of having to query bdrv_nb_sectors() for the size; and we can change the contract of refresh_total_sectors() to query the actual size before returning (remember, offset >> BDRV_SECTOR_BITS is only the hint size, and may differ from the actual size). That way, if refresh_total_sectors() succeeds, then bdrv_dirty_bitmap_truncate() cannot fail.

I'm not sure, however, how invasive it will be to make refresh_total_sectors() guarantee that it can return the actual size that was set even when that size differs from the hint. Still, it sounds like the right approach to take, so I'll play with it.

Signature · 3 lines
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org
author
#8 lore raw

PATCH v7 6/20 dirty-bitmap: Change bdrv_dirty_bitmap_size() to report bytes

In reply to Eric Blake

We're already reporting bytes for bdrv_dirty_bitmap_granularity(); mixing bytes and sectors in our return values is a recipe for confusion. A later cleanup will convert dirty bitmap internals to be entirely byte-based, but in the meantime, we should report the bitmap size in bytes.

The only external caller in qcow2-bitmap.c is temporarily more verbose (because it is still using sector-based math), but will later be switched to track progress by bytes instead of sectors.

---
v7: split external from internal change [Kevin], drop R-b
v6: no change
v5: fix bdrv_dirty_bitmap_truncate [John], drop R-b
v4: retitle from "Track size in bytes", rebase to persistent bitmaps, round up when converting bytes to sectors
v3: no change
v2: tweak commit message, no code change

---
 block/dirty-bitmap.c |  2 +-
 block/qcow2-bitmap.c | 14 ++++++++------
 2 files changed, 9 insertions(+), 7 deletions(-)
block/dirty-bitmap.c +1 -1
index 52f7a399b2..56a01699e9 100644
@@ -175,7 +175,7 @@ void bdrv_release_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap)
 
 int64_t bdrv_dirty_bitmap_size(const BdrvDirtyBitmap *bitmap)
 {
-    return bitmap->size;
+    return bitmap->size * BDRV_SECTOR_SIZE;
 }
 
 const char *bdrv_dirty_bitmap_name(const BdrvDirtyBitmap *bitmap)
block/qcow2-bitmap.c +8 -6
index b3ee4c794a..65122e9ae1 100644
@@ -295,10 +295,11 @@ static int load_bitmap_data(BlockDriverState *bs,
     BDRVQcow2State *s = bs->opaque;
     uint64_t sector, sbc;
     uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
+    uint64_t bm_sectors = DIV_ROUND_UP(bm_size, BDRV_SECTOR_SIZE);
     uint8_t *buf = NULL;
     uint64_t i, tab_size =
             size_to_clusters(s,
-                bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
+                bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_sectors));
 
     if (tab_size != bitmap_table_size || tab_size > BME_MAX_TABLE_SIZE) {
         return -EINVAL;
@@ -307,7 +308,7 @@ static int load_bitmap_data(BlockDriverState *bs,
     buf = g_malloc(s->cluster_size);
     sbc = sectors_covered_by_bitmap_cluster(s, bitmap);
     for (i = 0, sector = 0; i < tab_size; ++i, sector += sbc) {
-        uint64_t count = MIN(bm_size - sector, sbc);
+        uint64_t count = MIN(bm_sectors - sector, sbc);
         uint64_t entry = bitmap_table[i];
         uint64_t offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
 
@@ -1077,13 +1078,14 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
     int64_t sector;
     uint64_t sbc;
     uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
+    uint64_t bm_sectors = DIV_ROUND_UP(bm_size, BDRV_SECTOR_SIZE);
     const char *bm_name = bdrv_dirty_bitmap_name(bitmap);
     uint8_t *buf = NULL;
     BdrvDirtyBitmapIter *dbi;
     uint64_t *tb;
     uint64_t tb_size =
             size_to_clusters(s,
-                bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
+                bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_sectors));
 
     if (tb_size > BME_MAX_TABLE_SIZE ||
         tb_size * s->cluster_size > BME_MAX_PHYS_SIZE)
@@ -1101,7 +1103,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
     dbi = bdrv_dirty_iter_new(bitmap, 0);
     buf = g_malloc(s->cluster_size);
     sbc = sectors_covered_by_bitmap_cluster(s, bitmap);
-    assert(DIV_ROUND_UP(bm_size, sbc) == tb_size);
+    assert(DIV_ROUND_UP(bm_sectors, sbc) == tb_size);
 
     while ((sector = bdrv_dirty_iter_next(dbi)) != -1) {
         uint64_t cluster = sector / sbc;
@@ -1109,7 +1111,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
         int64_t off;
 
         sector = cluster * sbc;
-        end = MIN(bm_size, sector + sbc);
+        end = MIN(bm_sectors, sector + sbc);
         write_size =
             bdrv_dirty_bitmap_serialization_size(bitmap, sector, end - sector);
         assert(write_size <= s->cluster_size);
@@ -1141,7 +1143,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
             goto fail;
         }
 
-        if (end >= bm_size) {
+        if (end >= bm_sectors) {
             break;
         }
 
Signature · 1 line
2.13.5
Reviewed-by on v7 6/20
#9 lore raw

Re: [Qemu-devel] [PATCH v7 06/20] dirty-bitmap: Change bdrv_dirty_bitmap_size() to report bytes

Quoted 6 lines · Eric Blake

We're already reporting bytes for bdrv_dirty_bitmap_granularity(); mixing bytes and sectors in our return values is a recipe for confusion. A later cleanup will convert dirty bitmap internals to be entirely byte-based, but in the meantime, we should report the bitmap size in bytes.

Quoted 6 lines

The only external caller in qcow2-bitmap.c is temporarily more verbose (because it is still using sector-based math), but will later be switched to track progress by bytes instead of sectors.

author
#10 lore raw

PATCH v7 7/20 dirty-bitmap: Track bitmap size by bytes

In reply to 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 (mostly) an internal-only variable (remember, the size is how many bytes are covered by the bitmap, not how many bytes the bitmap occupies). A later cleanup will convert dirty bitmap internals to be entirely byte-based, eliminating the intermediate sector rounding added here; and technically, since bdrv_getlength() already rounds up to sectors, our use of DIV_ROUND_UP is more for theoretical completeness than for any actual rounding.

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

---
v7: split external from internal [Kevin], drop R-b
v6: no change
v5: fix bdrv_dirty_bitmap_truncate [John], drop R-b
v4: retitle from "Track size in bytes", rebase to persistent bitmaps, round up when converting bytes to sectors
v3: no change
v2: tweak commit message, no code change

---
 block/dirty-bitmap.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)
block/dirty-bitmap.c +14 -11
index 56a01699e9..ec4fc0e1ad 100644
@@ -42,7 +42,7 @@ 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 disabled. It ignores all writes to
                                    the device */
     int active_iterators;       /* How many iterators are active */
@@ -115,17 +115,14 @@ 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;
@@ -133,7 +130,12 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
     }
     bitmap = g_new0(BdrvDirtyBitmap, 1);
     bitmap->mutex = &bs->dirty_bitmap_mutex;
-    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(DIV_ROUND_UP(bitmap_size, BDRV_SECTOR_SIZE),
+                                   ctz32(granularity) - BDRV_SECTOR_BITS);
     bitmap->size = bitmap_size;
     bitmap->name = g_strdup(name);
     bitmap->disabled = false;
@@ -175,7 +177,7 @@ void bdrv_release_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap)
 
 int64_t bdrv_dirty_bitmap_size(const BdrvDirtyBitmap *bitmap)
 {
-    return bitmap->size * BDRV_SECTOR_SIZE;
+    return bitmap->size;
 }
 
 const char *bdrv_dirty_bitmap_name(const BdrvDirtyBitmap *bitmap)
@@ -305,7 +307,7 @@ BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap(BlockDriverState *bs,
 int bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
 {
     BdrvDirtyBitmap *bitmap;
-    int64_t size = bdrv_nb_sectors(bs);
+    int64_t size = bdrv_getlength(bs);
 
     if (size < 0) {
         return size;
@@ -314,7 +316,7 @@ int 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);
+        hbitmap_truncate(bitmap->bitmap, DIV_ROUND_UP(size, BDRV_SECTOR_SIZE));
         bitmap->size = size;
     }
     bdrv_dirty_bitmaps_unlock(bs);
@@ -553,7 +555,8 @@ 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(DIV_ROUND_UP(bitmap->size,
+                                                    BDRV_SECTOR_SIZE),
                                        hbitmap_granularity(backup));
         *out = backup;
     }
Signature · 1 line
2.13.5
Reviewed-by on v7 7/20
#11 lore raw

Re: [Qemu-devel] [PATCH v7 07/20] dirty-bitmap: Track bitmap size by bytes

Quoted 12 lines · 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 (mostly) an internal-only variable (remember, the size is how many bytes are covered by the bitmap, not how many bytes the bitmap occupies). A later cleanup will convert dirty bitmap internals to be entirely byte-based, eliminating the intermediate sector rounding added here; and technically, since bdrv_getlength() already rounds up to sectors, our use of DIV_ROUND_UP is more for theoretical completeness than for any actual rounding.

Quoted 4 lines

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

author
#12 lore raw

PATCH v7 8/20 dirty-bitmap: Change bdrv_dirty_bitmap_*serialize*() to take bytes

In reply to Eric Blake

Right now, the dirty-bitmap code exposes the fact that we use a scale of sector granularity in the underlying hbitmap to anything that wants to serialize a dirty bitmap. It's nicer to uniformly expose bytes as our dirty-bitmap interface, matching the previous change to bitmap size. The only caller to serialization is currently qcow2-cluster.c, which becomes a bit more verbose because it is still tracking sectors for other reasons, but a later patch will fix that to more uniformly use byte offsets everywhere. Likewise, within dirty-bitmap, we have to add more assertions that we are not truncating incorrectly, which can go away once the internal hbitmap is byte-based rather than sector-based.

---
v5: no change
v4: new patch

---
 include/block/dirty-bitmap.h | 14 +++++++-------
 block/dirty-bitmap.c         | 37 ++++++++++++++++++++++++-------------
 block/qcow2-bitmap.c         | 22 ++++++++++++++--------
 3 files changed, 45 insertions(+), 28 deletions(-)
include/block/dirty-bitmap.h +7 -7
index 15101b59d5..cd32149db6 100644
@@ -49,19 +49,19 @@ BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
 void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter);
 
 uint64_t bdrv_dirty_bitmap_serialization_size(const BdrvDirtyBitmap *bitmap,
-                                              uint64_t start, uint64_t count);
+                                              uint64_t offset, uint64_t bytes);
 uint64_t bdrv_dirty_bitmap_serialization_align(const BdrvDirtyBitmap *bitmap);
 void bdrv_dirty_bitmap_serialize_part(const BdrvDirtyBitmap *bitmap,
-                                      uint8_t *buf, uint64_t start,
-                                      uint64_t count);
+                                      uint8_t *buf, uint64_t offset,
+                                      uint64_t bytes);
 void bdrv_dirty_bitmap_deserialize_part(BdrvDirtyBitmap *bitmap,
-                                        uint8_t *buf, uint64_t start,
-                                        uint64_t count, bool finish);
+                                        uint8_t *buf, uint64_t offset,
+                                        uint64_t bytes, bool finish);
 void bdrv_dirty_bitmap_deserialize_zeroes(BdrvDirtyBitmap *bitmap,
-                                          uint64_t start, uint64_t count,
+                                          uint64_t offset, uint64_t bytes,
                                           bool finish);
 void bdrv_dirty_bitmap_deserialize_ones(BdrvDirtyBitmap *bitmap,
-                                        uint64_t start, uint64_t count,
+                                        uint64_t offset, uint64_t bytes,
                                         bool finish);
 void bdrv_dirty_bitmap_deserialize_finish(BdrvDirtyBitmap *bitmap);
 
block/dirty-bitmap.c +24 -13
index ec4fc0e1ad..dbf5a53044 100644
@@ -573,42 +573,53 @@ void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in)
 }
 
 uint64_t bdrv_dirty_bitmap_serialization_size(const BdrvDirtyBitmap *bitmap,
-                                              uint64_t start, uint64_t count)
+                                              uint64_t offset, uint64_t bytes)
 {
-    return hbitmap_serialization_size(bitmap->bitmap, start, count);
+    assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));
+    return hbitmap_serialization_size(bitmap->bitmap,
+                                      offset >> BDRV_SECTOR_BITS,
+                                      bytes >> BDRV_SECTOR_BITS);
 }
 
 uint64_t bdrv_dirty_bitmap_serialization_align(const BdrvDirtyBitmap *bitmap)
 {
-    return hbitmap_serialization_align(bitmap->bitmap);
+    return hbitmap_serialization_align(bitmap->bitmap) * BDRV_SECTOR_SIZE;
 }
 
 void bdrv_dirty_bitmap_serialize_part(const BdrvDirtyBitmap *bitmap,
-                                      uint8_t *buf, uint64_t start,
-                                      uint64_t count)
+                                      uint8_t *buf, uint64_t offset,
+                                      uint64_t bytes)
 {
-    hbitmap_serialize_part(bitmap->bitmap, buf, start, count);
+    assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));
+    hbitmap_serialize_part(bitmap->bitmap, buf, offset >> BDRV_SECTOR_BITS,
+                           bytes >> BDRV_SECTOR_BITS);
 }
 
 void bdrv_dirty_bitmap_deserialize_part(BdrvDirtyBitmap *bitmap,
-                                        uint8_t *buf, uint64_t start,
-                                        uint64_t count, bool finish)
+                                        uint8_t *buf, uint64_t offset,
+                                        uint64_t bytes, bool finish)
 {
-    hbitmap_deserialize_part(bitmap->bitmap, buf, start, count, finish);
+    assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));
+    hbitmap_deserialize_part(bitmap->bitmap, buf, offset >> BDRV_SECTOR_BITS,
+                             bytes >> BDRV_SECTOR_BITS, finish);
 }
 
 void bdrv_dirty_bitmap_deserialize_zeroes(BdrvDirtyBitmap *bitmap,
-                                          uint64_t start, uint64_t count,
+                                          uint64_t offset, uint64_t bytes,
                                           bool finish)
 {
-    hbitmap_deserialize_zeroes(bitmap->bitmap, start, count, finish);
+    assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));
+    hbitmap_deserialize_zeroes(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
+                               bytes >> BDRV_SECTOR_BITS, finish);
 }
 
 void bdrv_dirty_bitmap_deserialize_ones(BdrvDirtyBitmap *bitmap,
-                                        uint64_t start, uint64_t count,
+                                        uint64_t offset, uint64_t bytes,
                                         bool finish)
 {
-    hbitmap_deserialize_ones(bitmap->bitmap, start, count, finish);
+    assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));
+    hbitmap_deserialize_ones(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
+                             bytes >> BDRV_SECTOR_BITS, finish);
 }
 
 void bdrv_dirty_bitmap_deserialize_finish(BdrvDirtyBitmap *bitmap)
block/qcow2-bitmap.c +14 -8
index 65122e9ae1..92098bfa49 100644
@@ -278,7 +278,7 @@ static uint64_t sectors_covered_by_bitmap_cluster(const BDRVQcow2State *s,
             bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS;
     uint64_t sbc = sector_granularity * (s->cluster_size << 3);
 
-    assert(QEMU_IS_ALIGNED(sbc,
+    assert(QEMU_IS_ALIGNED(sbc << BDRV_SECTOR_BITS,
                            bdrv_dirty_bitmap_serialization_align(bitmap)));
     return sbc;
 }
@@ -299,7 +299,7 @@ static int load_bitmap_data(BlockDriverState *bs,
     uint8_t *buf = NULL;
     uint64_t i, tab_size =
             size_to_clusters(s,
-                bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_sectors));
+                bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
 
     if (tab_size != bitmap_table_size || tab_size > BME_MAX_TABLE_SIZE) {
         return -EINVAL;
@@ -316,7 +316,9 @@ static int load_bitmap_data(BlockDriverState *bs,
 
         if (offset == 0) {
             if (entry & BME_TABLE_ENTRY_FLAG_ALL_ONES) {
-                bdrv_dirty_bitmap_deserialize_ones(bitmap, sector, count,
+                bdrv_dirty_bitmap_deserialize_ones(bitmap,
+                                                   sector * BDRV_SECTOR_SIZE,
+                                                   count * BDRV_SECTOR_SIZE,
                                                    false);
             } else {
                 /* No need to deserialize zeros because the dirty bitmap is
@@ -327,7 +329,9 @@ static int load_bitmap_data(BlockDriverState *bs,
             if (ret < 0) {
                 goto finish;
             }
-            bdrv_dirty_bitmap_deserialize_part(bitmap, buf, sector, count,
+            bdrv_dirty_bitmap_deserialize_part(bitmap, buf,
+                                               sector * BDRV_SECTOR_SIZE,
+                                               count * BDRV_SECTOR_SIZE,
                                                false);
         }
     }
@@ -1085,7 +1089,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
     uint64_t *tb;
     uint64_t tb_size =
             size_to_clusters(s,
-                bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_sectors));
+                bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
 
     if (tb_size > BME_MAX_TABLE_SIZE ||
         tb_size * s->cluster_size > BME_MAX_PHYS_SIZE)
@@ -1112,8 +1116,8 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
 
         sector = cluster * sbc;
         end = MIN(bm_sectors, sector + sbc);
-        write_size =
-            bdrv_dirty_bitmap_serialization_size(bitmap, sector, end - sector);
+        write_size = bdrv_dirty_bitmap_serialization_size(bitmap,
+            sector * BDRV_SECTOR_SIZE, (end - sector) * BDRV_SECTOR_SIZE);
         assert(write_size <= s->cluster_size);
 
         off = qcow2_alloc_clusters(bs, s->cluster_size);
@@ -1125,7 +1129,9 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
         }
         tb[cluster] = off;
 
-        bdrv_dirty_bitmap_serialize_part(bitmap, buf, sector, end - sector);
+        bdrv_dirty_bitmap_serialize_part(bitmap, buf,
+                                         sector * BDRV_SECTOR_SIZE,
+                                         (end - sector) * BDRV_SECTOR_SIZE);
         if (write_size < s->cluster_size) {
             memset(buf + write_size, 0, s->cluster_size - write_size);
         }
Signature · 1 line
2.13.5
author
#13 lore raw

PATCH v7 9/20 qcow2: Switch sectors_covered_by_bitmap_cluster() to byte-based

In reply to Eric Blake

We are gradually converting to byte-based interfaces, as they are easier to reason about than sector-based. Change the qcow2 bitmap helper function sectors_covered_by_bitmap_cluster(), renaming it to bytes_covered_by_bitmap_cluster() in the process.

---
v5: no change
v4: new patch

---
 block/qcow2-bitmap.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)
block/qcow2-bitmap.c +14 -14
index 92098bfa49..4475273d8c 100644
@@ -269,18 +269,16 @@ static int free_bitmap_clusters(BlockDriverState *bs, Qcow2BitmapTable *tb)
     return 0;
 }
 
-/* This function returns the number of disk sectors covered by a single qcow2
- * cluster of bitmap data. */
-static uint64_t sectors_covered_by_bitmap_cluster(const BDRVQcow2State *s,
-                                                  const BdrvDirtyBitmap *bitmap)
+/* Return the disk size covered by a single qcow2 cluster of bitmap data. */
+static uint64_t bytes_covered_by_bitmap_cluster(const BDRVQcow2State *s,
+                                                const BdrvDirtyBitmap *bitmap)
 {
-    uint64_t sector_granularity =
-            bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS;
-    uint64_t sbc = sector_granularity * (s->cluster_size << 3);
+    uint64_t granularity = bdrv_dirty_bitmap_granularity(bitmap);
+    uint64_t limit = granularity * (s->cluster_size << 3);
 
-    assert(QEMU_IS_ALIGNED(sbc << BDRV_SECTOR_BITS,
+    assert(QEMU_IS_ALIGNED(limit,
                            bdrv_dirty_bitmap_serialization_align(bitmap)));
-    return sbc;
+    return limit;
 }
 
 /* load_bitmap_data
@@ -293,7 +291,7 @@ static int load_bitmap_data(BlockDriverState *bs,
 {
     int ret = 0;
     BDRVQcow2State *s = bs->opaque;
-    uint64_t sector, sbc;
+    uint64_t sector, limit, sbc;
     uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
     uint64_t bm_sectors = DIV_ROUND_UP(bm_size, BDRV_SECTOR_SIZE);
     uint8_t *buf = NULL;
@@ -306,7 +304,8 @@ static int load_bitmap_data(BlockDriverState *bs,
     }
 
     buf = g_malloc(s->cluster_size);
-    sbc = sectors_covered_by_bitmap_cluster(s, bitmap);
+    limit = bytes_covered_by_bitmap_cluster(s, bitmap);
+    sbc = limit >> BDRV_SECTOR_BITS;
     for (i = 0, sector = 0; i < tab_size; ++i, sector += sbc) {
         uint64_t count = MIN(bm_sectors - sector, sbc);
         uint64_t entry = bitmap_table[i];
@@ -1080,7 +1079,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
     int ret;
     BDRVQcow2State *s = bs->opaque;
     int64_t sector;
-    uint64_t sbc;
+    uint64_t limit, sbc;
     uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
     uint64_t bm_sectors = DIV_ROUND_UP(bm_size, BDRV_SECTOR_SIZE);
     const char *bm_name = bdrv_dirty_bitmap_name(bitmap);
@@ -1106,8 +1105,9 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
 
     dbi = bdrv_dirty_iter_new(bitmap, 0);
     buf = g_malloc(s->cluster_size);
-    sbc = sectors_covered_by_bitmap_cluster(s, bitmap);
-    assert(DIV_ROUND_UP(bm_sectors, sbc) == tb_size);
+    limit = bytes_covered_by_bitmap_cluster(s, bitmap);
+    sbc = limit >> BDRV_SECTOR_BITS;
+    assert(DIV_ROUND_UP(bm_size, limit) == tb_size);
 
     while ((sector = bdrv_dirty_iter_next(dbi)) != -1) {
         uint64_t cluster = sector / sbc;
Signature · 1 line
2.13.5
author
#14 lore raw

PATCH v7 10/20 dirty-bitmap: Set iterator start by offset, not sector

In reply to Eric Blake

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

Most callers to bdrv_set_dirty_iter() were scaling a byte offset to a sector number; the exception qcow2-bitmap will be converted later to use byte rather than sector iteration. Move the scaling to occur internally to dirty bitmap code instead, so that callers now pass in bytes.

---
v5: no change
v4: rebase to persistent bitmaps
v3: no change
v2: no change

---
 include/block/dirty-bitmap.h | 5 ++---
 block/backup.c               | 5 ++---
 block/dirty-bitmap.c         | 9 ++++-----
 block/mirror.c               | 4 ++--
 block/qcow2-bitmap.c         | 4 ++--
 5 files changed, 12 insertions(+), 15 deletions(-)
include/block/dirty-bitmap.h +2 -3
index cd32149db6..842e57416c 100644
@@ -44,8 +44,7 @@ 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);
 
 uint64_t bdrv_dirty_bitmap_serialization_size(const BdrvDirtyBitmap *bitmap,
@@ -80,7 +79,7 @@ void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
 void bdrv_reset_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
                                     int64_t cur_sector, int64_t nr_sectors);
 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);
 int bdrv_dirty_bitmap_truncate(BlockDriverState *bs);
block/backup.c +2 -3
index 517c300a49..ac9c018717 100644
@@ -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;
block/dirty-bitmap.c +4 -5
index dbf5a53044..d50c46621d 100644
@@ -478,11 +478,10 @@ uint32_t bdrv_dirty_bitmap_granularity(const 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;
@@ -650,9 +649,9 @@ 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)
block/mirror.c +2 -2
index 6531652d73..0b063b3c20 100644
@@ -373,7 +373,7 @@ 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);
@@ -796,7 +796,7 @@ 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;
block/qcow2-bitmap.c +2 -2
index 4475273d8c..44329fc74f 100644
@@ -1103,7 +1103,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
         return NULL;
     }
 
-    dbi = bdrv_dirty_iter_new(bitmap, 0);
+    dbi = bdrv_dirty_iter_new(bitmap);
     buf = g_malloc(s->cluster_size);
     limit = bytes_covered_by_bitmap_cluster(s, bitmap);
     sbc = limit >> BDRV_SECTOR_BITS;
@@ -1153,7 +1153,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
             break;
         }
 
-        bdrv_set_dirty_iter(dbi, end);
+        bdrv_set_dirty_iter(dbi, end * BDRV_SECTOR_SIZE);
     }
 
     *bitmap_table_size = tb_size;
Signature · 1 line
2.13.5
author
#15 lore raw

PATCH v7 11/20 dirty-bitmap: Change bdrv_dirty_iter_next() to report byte offset

In reply to Eric Blake

Thanks to recent cleanups, most callers were scaling a return value of sectors into bytes (the exception, in qcow2-bitmap, will be converted to byte-based iteration later). Update the interface to do the scaling internally instead.

In qcow2-bitmap, the code was specifically checking for an error to be -1; it is more robust to treat all negative values as an error, but at the same time it is also easy enough to ensure we return -1 (and not -512) on error.

---
v7: return -1, not -512; and fix qcow2-bitmap to check all negatives [Kevin]
v5-v6: no change
v4: rebase to persistent bitmap
v3: no change
v2: no change

---
 block/backup.c       | 2 +-
 block/dirty-bitmap.c | 3 ++-
 block/mirror.c       | 8 ++++----
 block/qcow2-bitmap.c | 2 +-
 4 files changed, 8 insertions(+), 7 deletions(-)
block/backup.c +1 -1
index ac9c018717..06ddbfd03d 100644
@@ -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 */
block/dirty-bitmap.c +2 -1
index d50c46621d..49229fd501 100644
@@ -508,7 +508,8 @@ void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)
 
 int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
 {
-    return hbitmap_iter_next(&iter->hbi);
+    int64_t ret = hbitmap_iter_next(&iter->hbi);
+    return ret < 0 ? -1 : ret * BDRV_SECTOR_SIZE;
 }
 
 /* Called within bdrv_dirty_bitmap_lock..unlock */
block/mirror.c +4 -4
index 0b063b3c20..77bf5aa3a4 100644
@@ -336,10 +336,10 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
     int max_io_bytes = MAX(s->buf_size / MAX_IN_FLIGHT, MAX_IO_BYTES);
 
     bdrv_dirty_bitmap_lock(s->dirty_bitmap);
-    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);
@@ -370,11 +370,11 @@ 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++;
block/qcow2-bitmap.c +1 -1
index 44329fc74f..b09010b1d3 100644
@@ -1109,7 +1109,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
     sbc = limit >> BDRV_SECTOR_BITS;
     assert(DIV_ROUND_UP(bm_size, limit) == tb_size);
 
-    while ((sector = bdrv_dirty_iter_next(dbi)) != -1) {
+    while ((sector = bdrv_dirty_iter_next(dbi) >> BDRV_SECTOR_BITS) >= 0) {
         uint64_t cluster = sector / sbc;
         uint64_t end, write_size;
         int64_t off;
Signature · 1 line
2.13.5
Reviewed-by on v7 11/20
#16 lore raw

Re: [Qemu-devel] [PATCH v7 11/20] dirty-bitmap: Change bdrv_dirty_iter_next() to report byte offset

Quoted 5 lines · Eric Blake

Thanks to recent cleanups, most callers were scaling a return value of sectors into bytes (the exception, in qcow2-bitmap, will be converted to byte-based iteration later). Update the interface to do the scaling internally instead.

Quoted 7 lines

In qcow2-bitmap, the code was specifically checking for an error to be -1; it is more robust to treat all negative values as an error, but at the same time it is also easy enough to ensure we return -1 (and not -512) on error.

This patch now smells like a bugfix and a separate incremental feature enhancement.

Do we need to backport the error-checking to a possible 2.10.1?

If no:

author
#17 lore raw

Re: [Qemu-devel] [PATCH v7 11/20] dirty-bitmap: Change bdrv_dirty_iter_next() to report byte offset

Quoted 13 lines · John Snow
Quoted 10 lines · Eric Blake

Thanks to recent cleanups, most callers were scaling a return value of sectors into bytes (the exception, in qcow2-bitmap, will be converted to byte-based iteration later). Update the interface to do the scaling internally instead.

In qcow2-bitmap, the code was specifically checking for an error to be -1; it is more robust to treat all negative values as an error, but at the same time it is also easy enough to ensure we return -1 (and not -512) on error.

Quoted 5 lines
Quoted 2 lines

This patch now smells like a bugfix and a separate incremental feature enhancement.

There is no bug without this patch; more of a fix to avoid a latent regression from happening in further changes. In v6, I (accidentally) had bdrv_dirty_iter_next() temporarily returning -512 instead of -1 on failure; changing the qcow2 code to treat all negatives instead of precisely -1 as error is enough to avoid that regression, but so also is fixing bdrv_dirty_iter_next() to always return -1 on failure. This patch does both, rather than either fix in isolation, but that means we don't need a backport.

Quoted 7 lines

Do we need to backport the error-checking to a possible 2.10.1?

If no:

Signature · 3 lines
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org
#18 lore raw

Re: [Qemu-devel] [PATCH v7 11/20] dirty-bitmap: Change bdrv_dirty_iter_next() to report byte offset

Quoted 14 lines · Eric Blake
Quoted 13 lines · John Snow
Quoted 10 lines · Eric Blake

Thanks to recent cleanups, most callers were scaling a return value of sectors into bytes (the exception, in qcow2-bitmap, will be converted to byte-based iteration later). Update the interface to do the scaling internally instead.

In qcow2-bitmap, the code was specifically checking for an error to be -1; it is more robust to treat all negative values as an error, but at the same time it is also easy enough to ensure we return -1 (and not -512) on error.

Quoted 7 lines
Quoted 5 lines
Quoted 2 lines

This patch now smells like a bugfix and a separate incremental feature enhancement.

There is no bug without this patch; more of a fix to avoid a latent

Ah, you're right, I see. Please take the RB.

Quoted 16 lines

regression from happening in further changes. In v6, I (accidentally) had bdrv_dirty_iter_next() temporarily returning -512 instead of -1 on failure; changing the qcow2 code to treat all negatives instead of precisely -1 as error is enough to avoid that regression, but so also is fixing bdrv_dirty_iter_next() to always return -1 on failure. This patch does both, rather than either fix in isolation, but that means we don't need a backport.

Quoted 7 lines

Do we need to backport the error-checking to a possible 2.10.1?

If no:

author
#19 lore raw

PATCH v7 12/20 dirty-bitmap: Change bdrv_get_dirty_count() to report bytes

In reply to Eric Blake

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

---
v7: fix one more trace caller [Kevin]
v4-v6: no change
v3: no change, add R-b
v2: no change

---
 block/dirty-bitmap.c |  4 ++--
 block/mirror.c       | 16 ++++++----------
 migration/block.c    |  2 +-
 3 files changed, 9 insertions(+), 13 deletions(-)
block/dirty-bitmap.c +2 -2
index 49229fd501..ee0afb5e1a 100644
@@ -428,7 +428,7 @@ 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);
@@ -657,7 +657,7 @@ 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)
block/mirror.c +6 -10
index 77bf5aa3a4..7113d47db4 100644
@@ -340,8 +340,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
     if (offset < 0) {
         bdrv_set_dirty_iter(s->dbi, 0);
         offset = bdrv_dirty_iter_next(s->dbi);
-        trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap) *
-                                  BDRV_SECTOR_SIZE);
+        trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap));
         assert(offset >= 0);
     }
     bdrv_dirty_bitmap_unlock(s->dirty_bitmap);
@@ -811,11 +810,10 @@ 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.
@@ -827,8 +825,7 @@ 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) {
@@ -869,7 +866,7 @@ 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);
@@ -888,8 +885,7 @@ 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)) {
migration/block.c +1 -1
index 9171f60028..a3512945da 100644
@@ -667,7 +667,7 @@ static int64_t get_remaining_dirty(void)
         aio_context_release(blk_get_aio_context(bmds->blk));
     }
 
-    return dirty << BDRV_SECTOR_BITS;
+    return dirty;
 }
 
 
Signature · 1 line
2.13.5
Reviewed-by on v7 12/20
#20 lore raw

Re: [Qemu-devel] [PATCH v7 12/20] dirty-bitmap: Change bdrv_get_dirty_count() to report bytes

Quoted 5 lines · Eric Blake

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

author
#21 lore raw

PATCH v7 13/20 dirty-bitmap: Change bdrv_get_dirty_locked() to take bytes

In reply to 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.

---
v4: only context change
v3: rebase to _locked rename was straightforward enough that R-b kept
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, 9 insertions(+), 9 deletions(-)
include/block/dirty-bitmap.h +2 -2
index 842e57416c..94a8d76f26 100644
@@ -72,8 +72,8 @@ void bdrv_dirty_bitmap_set_persistance(BdrvDirtyBitmap *bitmap,
 /* Functions that require manual locking.  */
 void bdrv_dirty_bitmap_lock(BdrvDirtyBitmap *bitmap);
 void bdrv_dirty_bitmap_unlock(BdrvDirtyBitmap *bitmap);
-int bdrv_get_dirty_locked(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
-                          int64_t sector);
+bool bdrv_get_dirty_locked(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
+                           int64_t offset);
 void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
                                   int64_t cur_sector, int64_t nr_sectors);
 void bdrv_reset_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
block/dirty-bitmap.c +4 -4
index ee0afb5e1a..96b15d232a 100644
@@ -443,13 +443,13 @@ BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
 }
 
 /* Called within bdrv_dirty_bitmap_lock..unlock */
-int bdrv_get_dirty_locked(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
-                          int64_t sector)
+bool bdrv_get_dirty_locked(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;
     }
 }
 
block/mirror.c +1 -2
index 7113d47db4..e36fc81df3 100644
@@ -361,8 +361,7 @@ 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_locked(source, s->dirty_bitmap,
-                                   next_offset >> BDRV_SECTOR_BITS)) {
+            !bdrv_get_dirty_locked(source, s->dirty_bitmap, next_offset)) {
             break;
         }
         if (test_bit(next_chunk, s->in_flight_bitmap)) {
migration/block.c +2 -1
index a3512945da..b618869661 100644
@@ -530,7 +530,8 @@ static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds,
             blk_mig_unlock();
         }
         bdrv_dirty_bitmap_lock(bmds->dirty_bitmap);
-        if (bdrv_get_dirty_locked(bs, bmds->dirty_bitmap, sector)) {
+        if (bdrv_get_dirty_locked(bs, bmds->dirty_bitmap,
+                                  sector * BDRV_SECTOR_SIZE)) {
             if (total_sectors - sector < BDRV_SECTORS_PER_DIRTY_CHUNK) {
                 nr_sectors = total_sectors - sector;
             } else {
Signature · 1 line
2.13.5
author
#22 lore raw

PATCH v7 14/20 dirty-bitmap: Change bdrv_[re]set_dirty_bitmap() to use bytes

In reply to 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.

---
v5: only context change
v4: only context change, due to rebasing to persistent bitmaps
v3: rebase to addition of _locked interfaces; complex enough that I dropped R-b
v2: no change

---
 include/block/dirty-bitmap.h |  8 ++++----
 block/dirty-bitmap.c         | 22 ++++++++++++++--------
 block/mirror.c               | 16 ++++++++--------
 migration/block.c            |  7 +++++--
 4 files changed, 31 insertions(+), 22 deletions(-)
include/block/dirty-bitmap.h +4 -4
index 94a8d76f26..252bb25c8e 100644
@@ -40,9 +40,9 @@ 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);
 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);
@@ -75,9 +75,9 @@ void bdrv_dirty_bitmap_unlock(BdrvDirtyBitmap *bitmap);
 bool bdrv_get_dirty_locked(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                            int64_t offset);
 void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
-                                  int64_t cur_sector, int64_t nr_sectors);
+                                  int64_t offset, int64_t bytes);
 void bdrv_reset_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
-                                    int64_t cur_sector, int64_t nr_sectors);
+                                    int64_t offset, int64_t bytes);
 int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter);
 void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t offset);
 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
block/dirty-bitmap.c +14 -8
index 96b15d232a..b1bbb98653 100644
@@ -514,35 +514,41 @@ int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
 
 /* Called within bdrv_dirty_bitmap_lock..unlock */
 void bdrv_set_dirty_bitmap_locked(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));
     assert(!bdrv_dirty_bitmap_readonly(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_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
-                           int64_t cur_sector, int64_t nr_sectors)
+                           int64_t offset, int64_t bytes)
 {
     bdrv_dirty_bitmap_lock(bitmap);
-    bdrv_set_dirty_bitmap_locked(bitmap, cur_sector, nr_sectors);
+    bdrv_set_dirty_bitmap_locked(bitmap, offset, bytes);
     bdrv_dirty_bitmap_unlock(bitmap);
 }
 
 /* Called within bdrv_dirty_bitmap_lock..unlock */
 void bdrv_reset_dirty_bitmap_locked(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));
     assert(!bdrv_dirty_bitmap_readonly(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_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
-                             int64_t cur_sector, int64_t nr_sectors)
+                             int64_t offset, int64_t bytes)
 {
     bdrv_dirty_bitmap_lock(bitmap);
-    bdrv_reset_dirty_bitmap_locked(bitmap, cur_sector, nr_sectors);
+    bdrv_reset_dirty_bitmap_locked(bitmap, offset, bytes);
     bdrv_dirty_bitmap_unlock(bitmap);
 }
 
block/mirror.c +8 -8
index e36fc81df3..c2f73c91c5 100644
@@ -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;
@@ -382,8 +380,8 @@ 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_locked(s->dirty_bitmap, offset >> BDRV_SECTOR_BITS,
-                                   nb_chunks * sectors_per_chunk);
+    bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, offset,
+                                   nb_chunks * s->granularity);
     bdrv_dirty_bitmap_unlock(s->dirty_bitmap);
 
     bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks);
@@ -625,7 +623,7 @@ 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;
         }
 
@@ -681,7 +679,9 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s)
         n = count >> BDRV_SECTOR_BITS;
         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;
     }
migration/block.c +5 -2
index b618869661..725f1974c3 100644
@@ -329,7 +329,8 @@ 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();
 
@@ -537,7 +538,9 @@ static int mig_save_device_dirty(QEMUFile *f, BlkMigDevState *bmds,
             } else {
                 nr_sectors = BDRV_SECTORS_PER_DIRTY_CHUNK;
             }
-            bdrv_reset_dirty_bitmap_locked(bmds->dirty_bitmap, sector, nr_sectors);
+            bdrv_reset_dirty_bitmap_locked(bmds->dirty_bitmap,
+                                           sector * BDRV_SECTOR_SIZE,
+                                           nr_sectors * BDRV_SECTOR_SIZE);
             bdrv_dirty_bitmap_unlock(bmds->dirty_bitmap);
 
             blk = g_new(BlkMigBlock, 1);
Signature · 1 line
2.13.5
author
#23 lore raw

PATCH v7 15/20 mirror: Switch mirror_dirty_init() to byte-based iteration

In reply to 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.

---
v6: no change
v5: rebase to earlier changes
v2-v4: no change

---
 block/mirror.c | 38 ++++++++++++++------------------------
 1 file changed, 14 insertions(+), 24 deletions(-)
block/mirror.c +14 -24
index c2f73c91c5..5cdaaed7be 100644
@@ -612,15 +612,13 @@ 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);
@@ -628,9 +626,9 @@ 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);
 
@@ -646,9 +644,8 @@ 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);
@@ -656,10 +653,10 @@ 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);
 
@@ -667,23 +664,16 @@ 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;
         }
 
-        /* TODO: Relax this once bdrv_is_allocated_above and dirty
-         * bitmaps no longer require sector alignment. */
-        assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
-        n = count >> BDRV_SECTOR_BITS;
-        assert(n > 0);
+        assert(count);
         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;
 }
Signature · 1 line
2.13.5
author
#24 lore raw

PATCH v7 16/20 qcow2: Switch qcow2_measure() to byte-based iteration

In reply to Eric Blake

This is new code, but it is easier to read if it makes passes over the image using bytes rather than sectors (and will get easier in the future when bdrv_get_block_status is converted to byte-based).

---
v7: tweak constant given to MIN (no semantic change, R-b kept) [Kevin]
v6: separate bug fix to earlier patch
v5: new patch

---
 block/qcow2.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)
block/qcow2.c +10 -12
index bae5893327..64dcd98a91 100644
@@ -3647,20 +3647,19 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,
              */
             required = virtual_size;
         } else {
-            int cluster_sectors = cluster_size / BDRV_SECTOR_SIZE;
-            int64_t sector_num;
+            int64_t offset;
             int pnum = 0;
 
-            for (sector_num = 0;
-                 sector_num < ssize / BDRV_SECTOR_SIZE;
-                 sector_num += pnum) {
-                int nb_sectors = MIN(ssize / BDRV_SECTOR_SIZE - sector_num,
-                                     BDRV_REQUEST_MAX_SECTORS);
+            for (offset = 0; offset < ssize;
+                 offset += pnum * BDRV_SECTOR_SIZE) {
+                int nb_sectors = MIN(ssize - offset,
+                                     BDRV_REQUEST_MAX_BYTES) / BDRV_SECTOR_SIZE;
                 BlockDriverState *file;
                 int64_t ret;
 
                 ret = bdrv_get_block_status_above(in_bs, NULL,
-                                                  sector_num, nb_sectors,
+                                                  offset >> BDRV_SECTOR_BITS,
+                                                  nb_sectors,
                                                   &pnum, &file);
                 if (ret < 0) {
                     error_setg_errno(&local_err, -ret,
@@ -3673,12 +3672,11 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,
                 } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) ==
                            (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) {
                     /* Extend pnum to end of cluster for next iteration */
-                    pnum = ROUND_UP(sector_num + pnum, cluster_sectors) -
-                           sector_num;
+                    pnum = (ROUND_UP(offset + pnum * BDRV_SECTOR_SIZE,
+                                 cluster_size) - offset) >> BDRV_SECTOR_BITS;
 
                     /* Count clusters we've seen */
-                    required += (sector_num % cluster_sectors + pnum) *
-                                BDRV_SECTOR_SIZE;
+                    required += offset % cluster_size + pnum * BDRV_SECTOR_SIZE;
                 }
             }
         }
Signature · 1 line
2.13.5
author
#25 lore raw

PATCH v7 17/20 qcow2: Switch load_bitmap_data() to byte-based iteration

In reply to 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.

---
v5: no change
v4: new patch

---
 block/qcow2-bitmap.c | 22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)
block/qcow2-bitmap.c +8 -14
index b09010b1d3..692ce0de88 100644
@@ -291,9 +291,8 @@ static int load_bitmap_data(BlockDriverState *bs,
 {
     int ret = 0;
     BDRVQcow2State *s = bs->opaque;
-    uint64_t sector, limit, sbc;
+    uint64_t offset, limit;
     uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
-    uint64_t bm_sectors = DIV_ROUND_UP(bm_size, BDRV_SECTOR_SIZE);
     uint8_t *buf = NULL;
     uint64_t i, tab_size =
             size_to_clusters(s,
@@ -305,32 +304,27 @@ static int load_bitmap_data(BlockDriverState *bs,
 
     buf = g_malloc(s->cluster_size);
     limit = bytes_covered_by_bitmap_cluster(s, bitmap);
-    sbc = limit >> BDRV_SECTOR_BITS;
-    for (i = 0, sector = 0; i < tab_size; ++i, sector += sbc) {
-        uint64_t count = MIN(bm_sectors - sector, sbc);
+    for (i = 0, offset = 0; i < tab_size; ++i, offset += limit) {
+        uint64_t count = MIN(bm_size - offset, limit);
         uint64_t entry = bitmap_table[i];
-        uint64_t offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
+        uint64_t data_offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
 
         assert(check_table_entry(entry, s->cluster_size) == 0);
 
-        if (offset == 0) {
+        if (data_offset == 0) {
             if (entry & BME_TABLE_ENTRY_FLAG_ALL_ONES) {
-                bdrv_dirty_bitmap_deserialize_ones(bitmap,
-                                                   sector * BDRV_SECTOR_SIZE,
-                                                   count * BDRV_SECTOR_SIZE,
+                bdrv_dirty_bitmap_deserialize_ones(bitmap, offset, count,
                                                    false);
             } else {
                 /* No need to deserialize zeros because the dirty bitmap is
                  * already cleared */
             }
         } else {
-            ret = bdrv_pread(bs->file, offset, buf, s->cluster_size);
+            ret = bdrv_pread(bs->file, data_offset, buf, s->cluster_size);
             if (ret < 0) {
                 goto finish;
             }
-            bdrv_dirty_bitmap_deserialize_part(bitmap, buf,
-                                               sector * BDRV_SECTOR_SIZE,
-                                               count * BDRV_SECTOR_SIZE,
+            bdrv_dirty_bitmap_deserialize_part(bitmap, buf, offset, count,
                                                false);
         }
     }
Signature · 1 line
2.13.5
author
#26 lore raw

PATCH v7 18/20 qcow2: Switch store_bitmap_data() to byte-based iteration

In reply to 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.

---
v7: rebase to earlier change, make rounding of offset obvious (no semantic change, so R-b kept) [Kevin]
v5-v6: no change
v4: new patch

---
 block/qcow2-bitmap.c | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)
block/qcow2-bitmap.c +11 -15
index 692ce0de88..302fffd6e1 100644
@@ -1072,10 +1072,9 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
 {
     int ret;
     BDRVQcow2State *s = bs->opaque;
-    int64_t sector;
-    uint64_t limit, sbc;
+    int64_t offset;
+    uint64_t limit;
     uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
-    uint64_t bm_sectors = DIV_ROUND_UP(bm_size, BDRV_SECTOR_SIZE);
     const char *bm_name = bdrv_dirty_bitmap_name(bitmap);
     uint8_t *buf = NULL;
     BdrvDirtyBitmapIter *dbi;
@@ -1100,18 +1099,17 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
     dbi = bdrv_dirty_iter_new(bitmap);
     buf = g_malloc(s->cluster_size);
     limit = bytes_covered_by_bitmap_cluster(s, bitmap);
-    sbc = limit >> BDRV_SECTOR_BITS;
     assert(DIV_ROUND_UP(bm_size, limit) == tb_size);
 
-    while ((sector = bdrv_dirty_iter_next(dbi) >> BDRV_SECTOR_BITS) >= 0) {
-        uint64_t cluster = sector / sbc;
+    while ((offset = bdrv_dirty_iter_next(dbi)) >= 0) {
+        uint64_t cluster = offset / limit;
         uint64_t end, write_size;
         int64_t off;
 
-        sector = cluster * sbc;
-        end = MIN(bm_sectors, sector + sbc);
-        write_size = bdrv_dirty_bitmap_serialization_size(bitmap,
-            sector * BDRV_SECTOR_SIZE, (end - sector) * BDRV_SECTOR_SIZE);
+        offset = QEMU_ALIGN_DOWN(offset, limit);
+        end = MIN(bm_size, offset + limit);
+        write_size = bdrv_dirty_bitmap_serialization_size(bitmap, offset,
+                                                          end - offset);
         assert(write_size <= s->cluster_size);
 
         off = qcow2_alloc_clusters(bs, s->cluster_size);
@@ -1123,9 +1121,7 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
         }
         tb[cluster] = off;
 
-        bdrv_dirty_bitmap_serialize_part(bitmap, buf,
-                                         sector * BDRV_SECTOR_SIZE,
-                                         (end - sector) * BDRV_SECTOR_SIZE);
+        bdrv_dirty_bitmap_serialize_part(bitmap, buf, offset, end - offset);
         if (write_size < s->cluster_size) {
             memset(buf + write_size, 0, s->cluster_size - write_size);
         }
@@ -1143,11 +1139,11 @@ static uint64_t *store_bitmap_data(BlockDriverState *bs,
             goto fail;
         }
 
-        if (end >= bm_sectors) {
+        if (end >= bm_size) {
             break;
         }
 
-        bdrv_set_dirty_iter(dbi, end * BDRV_SECTOR_SIZE);
+        bdrv_set_dirty_iter(dbi, end);
     }
 
     *bitmap_table_size = tb_size;
Signature · 1 line
2.13.5
author
#27 lore raw

PATCH v7 19/20 dirty-bitmap: Switch bdrv_set_dirty() to bytes

In reply to 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.

---
v4: only context changes
v3: rebase to lock context changes, R-b kept
v2: no change

---
 include/block/block_int.h | 2 +-
 block/io.c                | 6 ++----
 block/dirty-bitmap.c      | 7 ++++---
 3 files changed, 7 insertions(+), 8 deletions(-)
include/block/block_int.h +1 -1
index ba4c383393..55c5d573d4 100644
@@ -1021,7 +1021,7 @@ 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);
block/io.c +2 -4
index 4378ae4c7d..8a0cd8835a 100644
@@ -1334,7 +1334,6 @@ 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;
@@ -1409,7 +1408,7 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
     bdrv_debug_event(bs, BLKDBG_PWRITEV_DONE);
 
     atomic_inc(&bs->write_gen);
-    bdrv_set_dirty(bs, start_sector, end_sector - start_sector);
+    bdrv_set_dirty(bs, offset, bytes);
 
     stat64_max(&bs->wr_highest_offset, offset + bytes);
 
@@ -2438,8 +2437,7 @@ int coroutine_fn bdrv_co_pdiscard(BlockDriverState *bs, int64_t offset,
     ret = 0;
 out:
     atomic_inc(&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;
block/dirty-bitmap.c +4 -3
index b1bbb98653..dd91f56b94 100644
@@ -633,10 +633,10 @@ 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);
 
     if (QLIST_EMPTY(&bs->dirty_bitmaps)) {
         return;
@@ -648,7 +648,8 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
             continue;
         }
         assert(!bdrv_dirty_bitmap_readonly(bitmap));
-        hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
+        hbitmap_set(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
+                    end_sector - (offset >> BDRV_SECTOR_BITS));
     }
     bdrv_dirty_bitmaps_unlock(bs);
 }
Signature · 1 line
2.13.5
author
#28 lore raw

PATCH v7 20/20 dirty-bitmap: Convert internal hbitmap size/granularity

In reply to 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.

---
v7: rebase to dirty_iter_next cleanup (no semantic change, R-b kept)
v6: no change
v5: fix bdrv_dirty_bitmap_truncate [John]
v4: rebase to earlier changes, include serialization, R-b dropped
v3: no change
v2: no change

---
 block/dirty-bitmap.c | 62 +++++++++++++++-------------------------------------
 1 file changed, 18 insertions(+), 44 deletions(-)
block/dirty-bitmap.c +18 -44
index dd91f56b94..c2322c2619 100644
@@ -38,7 +38,7 @@
  */
 struct BdrvDirtyBitmap {
     QemuMutex *mutex;
-    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 */
@@ -130,12 +130,7 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
     }
     bitmap = g_new0(BdrvDirtyBitmap, 1);
     bitmap->mutex = &bs->dirty_bitmap_mutex;
-    /*
-     * TODO - let hbitmap track full granularity. For now, it is tracking
-     * only sector granularity, as a shortcut for our iterators.
-     */
-    bitmap->bitmap = hbitmap_alloc(DIV_ROUND_UP(bitmap_size, BDRV_SECTOR_SIZE),
-                                   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;
@@ -316,7 +311,7 @@ int 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, DIV_ROUND_UP(size, BDRV_SECTOR_SIZE));
+        hbitmap_truncate(bitmap->bitmap, size);
         bitmap->size = size;
     }
     bdrv_dirty_bitmaps_unlock(bs);
@@ -447,7 +442,7 @@ bool bdrv_get_dirty_locked(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;
     }
@@ -475,7 +470,7 @@ uint32_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs)
 
 uint32_t bdrv_dirty_bitmap_granularity(const BdrvDirtyBitmap *bitmap)
 {
-    return BDRV_SECTOR_SIZE << hbitmap_granularity(bitmap->bitmap);
+    return 1U << hbitmap_granularity(bitmap->bitmap);
 }
 
 BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap)
@@ -508,20 +503,16 @@ void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)
 
 int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)
 {
-    int64_t ret = hbitmap_iter_next(&iter->hbi);
-    return ret < 0 ? -1 : ret * BDRV_SECTOR_SIZE;
+    return hbitmap_iter_next(&iter->hbi);
 }
 
 /* Called within bdrv_dirty_bitmap_lock..unlock */
 void bdrv_set_dirty_bitmap_locked(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));
     assert(!bdrv_dirty_bitmap_readonly(bitmap));
-    hbitmap_set(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
-                end_sector - (offset >> BDRV_SECTOR_BITS));
+    hbitmap_set(bitmap->bitmap, offset, bytes);
 }
 
 void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
@@ -536,12 +527,9 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
 void bdrv_reset_dirty_bitmap_locked(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));
     assert(!bdrv_dirty_bitmap_readonly(bitmap));
-    hbitmap_reset(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
-                  end_sector - (offset >> BDRV_SECTOR_BITS));
+    hbitmap_reset(bitmap->bitmap, offset, bytes);
 }
 
 void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
@@ -561,8 +549,7 @@ void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out)
         hbitmap_reset_all(bitmap->bitmap);
     } else {
         HBitmap *backup = bitmap->bitmap;
-        bitmap->bitmap = hbitmap_alloc(DIV_ROUND_UP(bitmap->size,
-                                                    BDRV_SECTOR_SIZE),
+        bitmap->bitmap = hbitmap_alloc(bitmap->size,
                                        hbitmap_granularity(backup));
         *out = backup;
     }
@@ -581,51 +568,40 @@ void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in)
 uint64_t bdrv_dirty_bitmap_serialization_size(const BdrvDirtyBitmap *bitmap,
                                               uint64_t offset, uint64_t bytes)
 {
-    assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));
-    return hbitmap_serialization_size(bitmap->bitmap,
-                                      offset >> BDRV_SECTOR_BITS,
-                                      bytes >> BDRV_SECTOR_BITS);
+    return hbitmap_serialization_size(bitmap->bitmap, offset, bytes);
 }
 
 uint64_t bdrv_dirty_bitmap_serialization_align(const BdrvDirtyBitmap *bitmap)
 {
-    return hbitmap_serialization_align(bitmap->bitmap) * BDRV_SECTOR_SIZE;
+    return hbitmap_serialization_align(bitmap->bitmap);
 }
 
 void bdrv_dirty_bitmap_serialize_part(const BdrvDirtyBitmap *bitmap,
                                       uint8_t *buf, uint64_t offset,
                                       uint64_t bytes)
 {
-    assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));
-    hbitmap_serialize_part(bitmap->bitmap, buf, offset >> BDRV_SECTOR_BITS,
-                           bytes >> BDRV_SECTOR_BITS);
+    hbitmap_serialize_part(bitmap->bitmap, buf, offset, bytes);
 }
 
 void bdrv_dirty_bitmap_deserialize_part(BdrvDirtyBitmap *bitmap,
                                         uint8_t *buf, uint64_t offset,
                                         uint64_t bytes, bool finish)
 {
-    assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));
-    hbitmap_deserialize_part(bitmap->bitmap, buf, offset >> BDRV_SECTOR_BITS,
-                             bytes >> BDRV_SECTOR_BITS, finish);
+    hbitmap_deserialize_part(bitmap->bitmap, buf, offset, bytes, finish);
 }
 
 void bdrv_dirty_bitmap_deserialize_zeroes(BdrvDirtyBitmap *bitmap,
                                           uint64_t offset, uint64_t bytes,
                                           bool finish)
 {
-    assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));
-    hbitmap_deserialize_zeroes(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
-                               bytes >> BDRV_SECTOR_BITS, finish);
+    hbitmap_deserialize_zeroes(bitmap->bitmap, offset, bytes, finish);
 }
 
 void bdrv_dirty_bitmap_deserialize_ones(BdrvDirtyBitmap *bitmap,
                                         uint64_t offset, uint64_t bytes,
                                         bool finish)
 {
-    assert(QEMU_IS_ALIGNED(offset | bytes, BDRV_SECTOR_SIZE));
-    hbitmap_deserialize_ones(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
-                             bytes >> BDRV_SECTOR_BITS, finish);
+    hbitmap_deserialize_ones(bitmap->bitmap, offset, bytes, finish);
 }
 
 void bdrv_dirty_bitmap_deserialize_finish(BdrvDirtyBitmap *bitmap)
@@ -636,7 +612,6 @@ 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);
 
     if (QLIST_EMPTY(&bs->dirty_bitmaps)) {
         return;
@@ -648,8 +623,7 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes)
             continue;
         }
         assert(!bdrv_dirty_bitmap_readonly(bitmap));
-        hbitmap_set(bitmap->bitmap, offset >> BDRV_SECTOR_BITS,
-                    end_sector - (offset >> BDRV_SECTOR_BITS));
+        hbitmap_set(bitmap->bitmap, offset, bytes);
     }
     bdrv_dirty_bitmaps_unlock(bs);
 }
@@ -659,12 +633,12 @@ 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)
Signature · 1 line
2.13.5