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[Qemu-devel] [PATCH 16/31] qcow2: Update l2_allocate() to support L2 sli
From: |
Alberto Garcia |
Subject: |
[Qemu-devel] [PATCH 16/31] qcow2: Update l2_allocate() to support L2 slices |
Date: |
Thu, 12 Oct 2017 16:05:30 +0300 |
This patch updates l2_allocate() to support the qcow2 cache returning
L2 slices instead of full L2 tables.
The old code simply gets an L2 table from the cache and initializes it
with zeroes or with the contents of an existing table. With a cache
that returns slices instead of tables the idea remains the same, but
the code must now iterate over all the slices that are contained in an
L2 table.
Since now we're operating with slices the function can no longer
return the newly-allocated table, so it's up to the caller to retrieve
the appropriate L2 slice after calling l2_allocate() (note that with
this patch the caller is still loading full L2 tables, but we'll deal
with that in a separate patch).
Signed-off-by: Alberto Garcia <address@hidden>
---
block/qcow2-cluster.c | 86 +++++++++++++++++++++++++++++++--------------------
1 file changed, 52 insertions(+), 34 deletions(-)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index aafc19a21b..d3548cc667 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -264,11 +264,12 @@ int qcow2_write_l1_entry(BlockDriverState *bs, int
l1_index)
*
*/
-static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table)
+static int l2_allocate(BlockDriverState *bs, int l1_index)
{
BDRVQcow2State *s = bs->opaque;
uint64_t old_l2_offset;
- uint64_t *l2_table = NULL;
+ uint64_t *l2_slice = NULL;
+ unsigned slice, slice_size, n_slices;
int64_t l2_offset;
int ret;
@@ -291,42 +292,50 @@ static int l2_allocate(BlockDriverState *bs, int
l1_index, uint64_t **table)
/* allocate a new entry in the l2 cache */
+ slice_size = s->l2_slice_size * sizeof(uint64_t);
+ n_slices = s->cluster_size / slice_size;
+
trace_qcow2_l2_allocate_get_empty(bs, l1_index);
- ret = qcow2_cache_get_empty(bs, s->l2_table_cache, l2_offset, (void**)
table);
- if (ret < 0) {
- goto fail;
- }
-
- l2_table = *table;
-
- if ((old_l2_offset & L1E_OFFSET_MASK) == 0) {
- /* if there was no old l2 table, clear the new table */
- memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
- } else {
- uint64_t* old_table;
-
- /* if there was an old l2 table, read it from the disk */
- BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ);
- ret = qcow2_cache_get(bs, s->l2_table_cache,
- old_l2_offset & L1E_OFFSET_MASK,
- (void**) &old_table);
+ for (slice = 0; slice < n_slices; slice++) {
+ ret = qcow2_cache_get_empty(bs, s->l2_table_cache,
+ l2_offset + slice * slice_size,
+ (void **) &l2_slice);
if (ret < 0) {
goto fail;
}
- memcpy(l2_table, old_table, s->cluster_size);
+ if ((old_l2_offset & L1E_OFFSET_MASK) == 0) {
+ /* if there was no old l2 table, clear the new slice */
+ memset(l2_slice, 0, slice_size);
+ } else {
+ uint64_t *old_slice;
+ uint64_t old_l2_slice_offset =
+ (old_l2_offset & L1E_OFFSET_MASK) + slice * slice_size;
+
+ /* if there was an old l2 table, read an slice from the disk */
+ BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ);
+ ret = qcow2_cache_get(bs, s->l2_table_cache, old_l2_slice_offset,
+ (void **) &old_slice);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ memcpy(l2_slice, old_slice, slice_size);
- qcow2_cache_put(s->l2_table_cache, (void **) &old_table);
- }
+ qcow2_cache_put(s->l2_table_cache, (void **) &old_slice);
+ }
+
+ /* write the l2 slice to the file */
+ BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE);
- /* write the l2 table to the file */
- BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE);
+ trace_qcow2_l2_allocate_write_l2(bs, l1_index);
+ qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
+ ret = qcow2_cache_flush(bs, s->l2_table_cache);
+ if (ret < 0) {
+ goto fail;
+ }
- trace_qcow2_l2_allocate_write_l2(bs, l1_index);
- qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
- ret = qcow2_cache_flush(bs, s->l2_table_cache);
- if (ret < 0) {
- goto fail;
+ qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
}
/* update the L1 entry */
@@ -337,14 +346,13 @@ static int l2_allocate(BlockDriverState *bs, int
l1_index, uint64_t **table)
goto fail;
}
- *table = l2_table;
trace_qcow2_l2_allocate_done(bs, l1_index, 0);
return 0;
fail:
trace_qcow2_l2_allocate_done(bs, l1_index, ret);
- if (l2_table != NULL) {
- qcow2_cache_put(s->l2_table_cache, (void **) table);
+ if (l2_slice != NULL) {
+ qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
}
s->l1_table[l1_index] = old_l2_offset;
if (l2_offset > 0) {
@@ -688,8 +696,18 @@ static int get_cluster_table(BlockDriverState *bs,
uint64_t offset,
return ret;
}
} else {
+ uint64_t new_l2_offset;
/* First allocate a new L2 table (and do COW if needed) */
- ret = l2_allocate(bs, l1_index, &l2_table);
+ ret = l2_allocate(bs, l1_index);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /* Get the offset of the newly-allocated l2 table */
+ new_l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK;
+ assert(offset_into_cluster(s, new_l2_offset) == 0);
+ /* Load the l2 table in memory */
+ ret = l2_load(bs, offset, new_l2_offset, &l2_table);
if (ret < 0) {
return ret;
}
--
2.11.0
- [Qemu-devel] [PATCH 23/31] qcow2: Update zero_single_l2() to support L2 slices, (continued)
- [Qemu-devel] [PATCH 23/31] qcow2: Update zero_single_l2() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 22/31] qcow2: Update discard_single_l2() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 21/31] qcow2: Update handle_alloc() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 20/31] qcow2: Update handle_copied() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 19/31] qcow2: Update qcow2_alloc_cluster_link_l2() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 18/31] qcow2: Update qcow2_get_cluster_offset() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 08/31] qcow2: Remove BDS parameter from qcow2_cache_destroy(), Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 10/31] qcow2: Remove BDS parameter from qcow2_cache_discard(), Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 12/31] qcow2: Add offset_to_l1_index(), Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 07/31] qcow2: Remove BDS parameter from qcow2_cache_put(), Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 16/31] qcow2: Update l2_allocate() to support L2 slices,
Alberto Garcia <=
- [Qemu-devel] [PATCH 11/31] qcow2: Remove BDS parameter from qcow2_cache_is_table_offset(), Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 06/31] qcow2: Remove BDS parameter from qcow2_cache_entry_mark_dirty(), Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 15/31] qcow2: Update l2_load() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 05/31] qcow2: Remove BDS parameter from qcow2_cache_table_release(), Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 14/31] qcow2: Add offset_to_l2_slice_index(), Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 09/31] qcow2: Remove BDS parameter from qcow2_cache_clean_unused(), Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 17/31] qcow2: Update get_cluster_table() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 04/31] qcow2: Remove BDS parameter from qcow2_cache_get_table_idx(), Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 13/31] qcow2: Add l2_slice_size field to BDRVQcow2State, Alberto Garcia, 2017/10/12
- [Qemu-devel] [PATCH 03/31] qcow2: Remove BDS parameter from qcow2_cache_get_table_addr(), Alberto Garcia, 2017/10/12