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[Qemu-devel] [RFC][PATCH 2/2] qcow2: Use QcowCache
|
From: |
Kevin Wolf |
|
Subject: |
[Qemu-devel] [RFC][PATCH 2/2] qcow2: Use QcowCache |
|
Date: |
Mon, 10 Jan 2011 17:53:48 +0100 |
Use the new functions of qcow2-cache.c for everything that works on refcount
block and L2 tables.
Signed-off-by: Kevin Wolf <address@hidden>
---
block/qcow2-cluster.c | 206 ++++++++++++++--------------------------
block/qcow2-refcount.c | 249 +++++++++++++++++++-----------------------------
block/qcow2.c | 43 ++++++++-
block/qcow2.h | 12 ++-
4 files changed, 216 insertions(+), 294 deletions(-)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 6928c63..626a331 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -67,7 +67,11 @@ int qcow2_grow_l1_table(BlockDriverState *bs, int min_size,
bool exact_size)
qemu_free(new_l1_table);
return new_l1_table_offset;
}
- bdrv_flush(bs->file);
+
+ ret = qcow2_cache_flush(bs, s->refcount_block_cache);
+ if (ret < 0) {
+ return ret;
+ }
BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_WRITE_TABLE);
for(i = 0; i < s->l1_size; i++)
@@ -98,63 +102,6 @@ int qcow2_grow_l1_table(BlockDriverState *bs, int min_size,
bool exact_size)
return ret;
}
-void qcow2_l2_cache_reset(BlockDriverState *bs)
-{
- BDRVQcowState *s = bs->opaque;
-
- memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
- memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
- memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
-}
-
-static inline int l2_cache_new_entry(BlockDriverState *bs)
-{
- BDRVQcowState *s = bs->opaque;
- uint32_t min_count;
- int min_index, i;
-
- /* find a new entry in the least used one */
- min_index = 0;
- min_count = 0xffffffff;
- for(i = 0; i < L2_CACHE_SIZE; i++) {
- if (s->l2_cache_counts[i] < min_count) {
- min_count = s->l2_cache_counts[i];
- min_index = i;
- }
- }
- return min_index;
-}
-
-/*
- * seek_l2_table
- *
- * seek l2_offset in the l2_cache table
- * if not found, return NULL,
- * if found,
- * increments the l2 cache hit count of the entry,
- * if counter overflow, divide by two all counters
- * return the pointer to the l2 cache entry
- *
- */
-
-static uint64_t *seek_l2_table(BDRVQcowState *s, uint64_t l2_offset)
-{
- int i, j;
-
- for(i = 0; i < L2_CACHE_SIZE; i++) {
- if (l2_offset == s->l2_cache_offsets[i]) {
- /* increment the hit count */
- if (++s->l2_cache_counts[i] == 0xffffffff) {
- for(j = 0; j < L2_CACHE_SIZE; j++) {
- s->l2_cache_counts[j] >>= 1;
- }
- }
- return s->l2_cache + (i << s->l2_bits);
- }
- }
- return NULL;
-}
-
/*
* l2_load
*
@@ -169,33 +116,12 @@ static int l2_load(BlockDriverState *bs, uint64_t
l2_offset,
uint64_t **l2_table)
{
BDRVQcowState *s = bs->opaque;
- int min_index;
int ret;
- /* seek if the table for the given offset is in the cache */
-
- *l2_table = seek_l2_table(s, l2_offset);
- if (*l2_table != NULL) {
- return 0;
- }
-
- /* not found: load a new entry in the least used one */
-
- min_index = l2_cache_new_entry(bs);
- *l2_table = s->l2_cache + (min_index << s->l2_bits);
-
BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD);
- ret = bdrv_pread(bs->file, l2_offset, *l2_table,
- s->l2_size * sizeof(uint64_t));
- if (ret < 0) {
- qcow2_l2_cache_reset(bs);
- return ret;
- }
+ ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, (void**) l2_table);
- s->l2_cache_offsets[min_index] = l2_offset;
- s->l2_cache_counts[min_index] = 1;
-
- return 0;
+ return ret;
}
/*
@@ -238,7 +164,6 @@ static int write_l1_entry(BlockDriverState *bs, int
l1_index)
static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table)
{
BDRVQcowState *s = bs->opaque;
- int min_index;
uint64_t old_l2_offset;
uint64_t *l2_table;
int64_t l2_offset;
@@ -252,29 +177,48 @@ static int l2_allocate(BlockDriverState *bs, int
l1_index, uint64_t **table)
if (l2_offset < 0) {
return l2_offset;
}
- bdrv_flush(bs->file);
+
+ ret = qcow2_cache_flush(bs, s->refcount_block_cache);
+ if (ret < 0) {
+ goto fail;
+ }
/* allocate a new entry in the l2 cache */
- min_index = l2_cache_new_entry(bs);
- l2_table = s->l2_cache + (min_index << s->l2_bits);
+ ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, (void**) table);
+ if (ret < 0) {
+ return ret;
+ }
+
+ l2_table = *table;
if (old_l2_offset == 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 = bdrv_pread(bs->file, old_l2_offset, l2_table,
- s->l2_size * sizeof(uint64_t));
+ ret = qcow2_cache_get(bs, s->l2_table_cache, old_l2_offset,
+ (void**) &old_table);
+ if (ret < 0) {
+ goto fail;
+ }
+
+ memcpy(l2_table, old_table, s->cluster_size);
+
+ ret = qcow2_cache_put(bs, s->l2_table_cache, old_table);
if (ret < 0) {
goto fail;
}
}
+
/* write the l2 table to the file */
BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE);
- ret = bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
- s->l2_size * sizeof(uint64_t));
+
+ 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;
}
@@ -286,17 +230,12 @@ static int l2_allocate(BlockDriverState *bs, int
l1_index, uint64_t **table)
goto fail;
}
- /* update the l2 cache entry */
-
- s->l2_cache_offsets[min_index] = l2_offset;
- s->l2_cache_counts[min_index] = 1;
-
*table = l2_table;
return 0;
fail:
+ qcow2_cache_put(bs, s->l2_table_cache, *table);
s->l1_table[l1_index] = old_l2_offset;
- qcow2_l2_cache_reset(bs);
return ret;
}
@@ -521,6 +460,8 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t
offset,
&l2_table[l2_index], 0, QCOW_OFLAG_COPIED);
}
+ qcow2_cache_put(bs, s->l2_table_cache, l2_table);
+
nb_available = (c * s->cluster_sectors);
out:
if (nb_available > nb_needed)
@@ -575,6 +516,7 @@ static int get_cluster_table(BlockDriverState *bs, uint64_t
offset,
return ret;
}
} else {
+ /* FIXME Order */
if (l2_offset)
qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
ret = l2_allocate(bs, l1_index, &l2_table);
@@ -632,6 +574,7 @@ uint64_t
qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
cluster_offset = qcow2_alloc_bytes(bs, compressed_size);
if (cluster_offset < 0) {
+ qcow2_cache_put(bs, s->l2_table_cache, l2_table);
return 0;
}
@@ -646,38 +589,14 @@ uint64_t
qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
/* compressed clusters never have the copied flag */
BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
+ qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
l2_table[l2_index] = cpu_to_be64(cluster_offset);
- if (bdrv_pwrite_sync(bs->file,
- l2_offset + l2_index * sizeof(uint64_t),
- l2_table + l2_index,
- sizeof(uint64_t)) < 0)
- return 0;
-
- return cluster_offset;
-}
-
-/*
- * Write L2 table updates to disk, writing whole sectors to avoid a
- * read-modify-write in bdrv_pwrite
- */
-#define L2_ENTRIES_PER_SECTOR (512 / 8)
-static int write_l2_entries(BlockDriverState *bs, uint64_t *l2_table,
- uint64_t l2_offset, int l2_index, int num)
-{
- int l2_start_index = l2_index & ~(L1_ENTRIES_PER_SECTOR - 1);
- int start_offset = (8 * l2_index) & ~511;
- int end_offset = (8 * (l2_index + num) + 511) & ~511;
- size_t len = end_offset - start_offset;
- int ret;
-
- BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE);
- ret = bdrv_pwrite(bs->file, l2_offset + start_offset,
- &l2_table[l2_start_index], len);
+ ret = qcow2_cache_put(bs, s->l2_table_cache, l2_table);
if (ret < 0) {
- return ret;
+ return 0;
}
- return 0;
+ return cluster_offset;
}
int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
@@ -686,6 +605,7 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs,
QCowL2Meta *m)
int i, j = 0, l2_index, ret;
uint64_t *old_cluster, start_sect, l2_offset, *l2_table;
uint64_t cluster_offset = m->cluster_offset;
+ bool cow = false;
if (m->nb_clusters == 0)
return 0;
@@ -695,6 +615,7 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs,
QCowL2Meta *m)
/* copy content of unmodified sectors */
start_sect = (m->offset & ~(s->cluster_size - 1)) >> 9;
if (m->n_start) {
+ cow = true;
ret = copy_sectors(bs, start_sect, cluster_offset, 0, m->n_start);
if (ret < 0)
goto err;
@@ -702,17 +623,30 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs,
QCowL2Meta *m)
if (m->nb_available & (s->cluster_sectors - 1)) {
uint64_t end = m->nb_available & ~(uint64_t)(s->cluster_sectors - 1);
+ cow = true;
ret = copy_sectors(bs, start_sect + end, cluster_offset + (end << 9),
m->nb_available - end, s->cluster_sectors);
if (ret < 0)
goto err;
}
- /* update L2 table */
+ /*
+ * Update L2 table.
+ *
+ * Before we update the L2 table to actually point to the new cluster, we
+ * need to be sure that the refcounts have been increased and COW was
+ * handled.
+ */
+ if (cow) {
+ bdrv_flush(bs->file);
+ }
+
+ qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache);
ret = get_cluster_table(bs, m->offset, &l2_table, &l2_offset, &l2_index);
if (ret < 0) {
goto err;
}
+ qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
for (i = 0; i < m->nb_clusters; i++) {
/* if two concurrent writes happen to the same unallocated cluster
@@ -728,16 +662,9 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs,
QCowL2Meta *m)
(i << s->cluster_bits)) | QCOW_OFLAG_COPIED);
}
- /*
- * Before we update the L2 table to actually point to the new cluster, we
- * need to be sure that the refcounts have been increased and COW was
- * handled.
- */
- bdrv_flush(bs->file);
- ret = write_l2_entries(bs, l2_table, l2_offset, l2_index, m->nb_clusters);
+ ret = qcow2_cache_put(bs, s->l2_table_cache, l2_table);
if (ret < 0) {
- qcow2_l2_cache_reset(bs);
goto err;
}
@@ -868,7 +795,8 @@ int qcow2_alloc_cluster_offset(BlockDriverState *bs,
uint64_t offset,
m->depends_on = old_alloc;
m->nb_clusters = 0;
*num = 0;
- return 0;
+ ret = 0;
+ goto fail;
}
}
}
@@ -884,7 +812,8 @@ int qcow2_alloc_cluster_offset(BlockDriverState *bs,
uint64_t offset,
cluster_offset = qcow2_alloc_clusters(bs, nb_clusters * s->cluster_size);
if (cluster_offset < 0) {
QLIST_REMOVE(m, next_in_flight);
- return cluster_offset;
+ ret = cluster_offset;
+ goto fail;
}
/* save info needed for meta data update */
@@ -893,12 +822,21 @@ int qcow2_alloc_cluster_offset(BlockDriverState *bs,
uint64_t offset,
m->nb_clusters = nb_clusters;
out:
+ ret = qcow2_cache_put(bs, s->l2_table_cache, l2_table);
+ if (ret < 0) {
+ return ret;
+ }
+
m->nb_available = MIN(nb_clusters << (s->cluster_bits - 9), n_end);
m->cluster_offset = cluster_offset;
*num = m->nb_available - n_start;
return 0;
+
+fail:
+ qcow2_cache_put(bs, s->l2_table_cache, l2_table);
+ return ret;
}
static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index a10453c..23c6d79 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -32,27 +32,6 @@ static int QEMU_WARN_UNUSED_RESULT
update_refcount(BlockDriverState *bs,
int addend);
-static int cache_refcount_updates = 0;
-
-static int write_refcount_block(BlockDriverState *bs)
-{
- BDRVQcowState *s = bs->opaque;
- size_t size = s->cluster_size;
-
- if (s->refcount_block_cache_offset == 0) {
- return 0;
- }
-
- BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE);
- if (bdrv_pwrite_sync(bs->file, s->refcount_block_cache_offset,
- s->refcount_block_cache, size) < 0)
- {
- return -EIO;
- }
-
- return 0;
-}
-
/*********************************************************/
/* refcount handling */
@@ -61,7 +40,6 @@ int qcow2_refcount_init(BlockDriverState *bs)
BDRVQcowState *s = bs->opaque;
int ret, refcount_table_size2, i;
- s->refcount_block_cache = qemu_malloc(s->cluster_size);
refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t);
s->refcount_table = qemu_malloc(refcount_table_size2);
if (s->refcount_table_size > 0) {
@@ -81,34 +59,22 @@ int qcow2_refcount_init(BlockDriverState *bs)
void qcow2_refcount_close(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
- qemu_free(s->refcount_block_cache);
qemu_free(s->refcount_table);
}
static int load_refcount_block(BlockDriverState *bs,
- int64_t refcount_block_offset)
+ int64_t refcount_block_offset,
+ void **refcount_block)
{
BDRVQcowState *s = bs->opaque;
int ret;
- if (cache_refcount_updates) {
- ret = write_refcount_block(bs);
- if (ret < 0) {
- return ret;
- }
- }
-
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_LOAD);
- ret = bdrv_pread(bs->file, refcount_block_offset, s->refcount_block_cache,
- s->cluster_size);
- if (ret < 0) {
- s->refcount_block_cache_offset = 0;
- return ret;
- }
+ ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset,
+ refcount_block);
- s->refcount_block_cache_offset = refcount_block_offset;
- return 0;
+ return ret;
}
/*
@@ -122,6 +88,8 @@ static int get_refcount(BlockDriverState *bs, int64_t
cluster_index)
int refcount_table_index, block_index;
int64_t refcount_block_offset;
int ret;
+ uint16_t *refcount_block;
+ uint16_t refcount;
refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
if (refcount_table_index >= s->refcount_table_size)
@@ -129,16 +97,23 @@ static int get_refcount(BlockDriverState *bs, int64_t
cluster_index)
refcount_block_offset = s->refcount_table[refcount_table_index];
if (!refcount_block_offset)
return 0;
- if (refcount_block_offset != s->refcount_block_cache_offset) {
- /* better than nothing: return allocated if read error */
- ret = load_refcount_block(bs, refcount_block_offset);
- if (ret < 0) {
- return ret;
- }
+
+ ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset,
+ (void**) &refcount_block);
+ if (ret < 0) {
+ return ret;
}
+
block_index = cluster_index &
((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
- return be16_to_cpu(s->refcount_block_cache[block_index]);
+ refcount = be16_to_cpu(refcount_block[block_index]);
+
+ ret = qcow2_cache_put(bs, s->refcount_block_cache, refcount_block);
+ if (ret < 0) {
+ return ret;
+ }
+
+ return refcount;
}
/*
@@ -174,9 +149,10 @@ static int in_same_refcount_block(BDRVQcowState *s,
uint64_t offset_a,
* Loads a refcount block. If it doesn't exist yet, it is allocated first
* (including growing the refcount table if needed).
*
- * Returns the offset of the refcount block on success or -errno in error case
+ * Returns 0 on success or -errno in error case
*/
-static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t
cluster_index)
+static int alloc_refcount_block(BlockDriverState *bs,
+ int64_t cluster_index, uint16_t **refcount_block)
{
BDRVQcowState *s = bs->opaque;
unsigned int refcount_table_index;
@@ -194,13 +170,8 @@ static int64_t alloc_refcount_block(BlockDriverState *bs,
int64_t cluster_index)
/* If it's already there, we're done */
if (refcount_block_offset) {
- if (refcount_block_offset != s->refcount_block_cache_offset) {
- ret = load_refcount_block(bs, refcount_block_offset);
- if (ret < 0) {
- return ret;
- }
- }
- return refcount_block_offset;
+ return load_refcount_block(bs, refcount_block_offset,
+ (void**) refcount_block);
}
}
@@ -226,12 +197,10 @@ static int64_t alloc_refcount_block(BlockDriverState *bs,
int64_t cluster_index)
* refcount block into the cache
*/
- if (cache_refcount_updates) {
- ret = write_refcount_block(bs);
- if (ret < 0) {
- return ret;
- }
- }
+ *refcount_block = NULL;
+
+ /* We write to the refcount table, so we might depend on L2 tables */
+ qcow2_cache_flush(bs, s->l2_table_cache);
/* Allocate the refcount block itself and mark it as used */
int64_t new_block = alloc_clusters_noref(bs, s->cluster_size);
@@ -247,13 +216,18 @@ static int64_t alloc_refcount_block(BlockDriverState *bs,
int64_t cluster_index)
if (in_same_refcount_block(s, new_block, cluster_index <<
s->cluster_bits)) {
/* Zero the new refcount block before updating it */
- memset(s->refcount_block_cache, 0, s->cluster_size);
- s->refcount_block_cache_offset = new_block;
+ ret = qcow2_cache_get(bs, s->refcount_block_cache, new_block,
+ (void**) refcount_block);
+ if (ret < 0) {
+ goto fail_block;
+ }
+
+ memset(*refcount_block, 0, s->cluster_size);
/* The block describes itself, need to update the cache */
int block_index = (new_block >> s->cluster_bits) &
((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
- s->refcount_block_cache[block_index] = cpu_to_be16(1);
+ (*refcount_block)[block_index] = cpu_to_be16(1);
} else {
/* Described somewhere else. This can recurse at most twice before we
* arrive at a block that describes itself. */
@@ -266,14 +240,19 @@ static int64_t alloc_refcount_block(BlockDriverState *bs,
int64_t cluster_index)
/* Initialize the new refcount block only after updating its refcount,
* update_refcount uses the refcount cache itself */
- memset(s->refcount_block_cache, 0, s->cluster_size);
- s->refcount_block_cache_offset = new_block;
+ ret = qcow2_cache_get(bs, s->refcount_block_cache, new_block,
+ (void**) refcount_block);
+ if (ret < 0) {
+ goto fail_block;
+ }
+
+ memset(*refcount_block, 0, s->cluster_size);
}
/* Now the new refcount block needs to be written to disk */
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE);
- ret = bdrv_pwrite_sync(bs->file, new_block, s->refcount_block_cache,
- s->cluster_size);
+ qcow2_cache_entry_mark_dirty(s->refcount_block_cache, *refcount_block);
+ ret = qcow2_cache_flush(bs, s->refcount_block_cache);
if (ret < 0) {
goto fail_block;
}
@@ -293,6 +272,12 @@ static int64_t alloc_refcount_block(BlockDriverState *bs,
int64_t cluster_index)
return new_block;
}
+ ret = qcow2_cache_put(bs, s->refcount_block_cache, *refcount_block);
+ if (ret < 0) {
+ goto fail_block;
+ }
+ *refcount_block = NULL;
+
/*
* If we come here, we need to grow the refcount table. Again, a new
* refcount table needs some space and we can't simply allocate to avoid
@@ -410,9 +395,9 @@ static int64_t alloc_refcount_block(BlockDriverState *bs,
int64_t cluster_index)
qcow2_free_clusters(bs, old_table_offset, old_table_size *
sizeof(uint64_t));
s->free_cluster_index = old_free_cluster_index;
- ret = load_refcount_block(bs, new_block);
+ ret = load_refcount_block(bs, new_block, (void**) refcount_block);
if (ret < 0) {
- goto fail_block;
+ return ret;
}
return new_block;
@@ -420,41 +405,11 @@ static int64_t alloc_refcount_block(BlockDriverState *bs,
int64_t cluster_index)
fail_table:
qemu_free(new_table);
fail_block:
- s->refcount_block_cache_offset = 0;
- return ret;
-}
-
-#define REFCOUNTS_PER_SECTOR (512 >> REFCOUNT_SHIFT)
-static int write_refcount_block_entries(BlockDriverState *bs,
- int64_t refcount_block_offset, int first_index, int last_index)
-{
- BDRVQcowState *s = bs->opaque;
- size_t size;
- int ret;
-
- if (cache_refcount_updates) {
- return 0;
- }
-
- if (first_index < 0) {
- return 0;
+ if (*refcount_block != NULL) {
+ qcow2_cache_put(bs, s->refcount_block_cache, *refcount_block);
+ *refcount_block = NULL;
}
-
- first_index &= ~(REFCOUNTS_PER_SECTOR - 1);
- last_index = (last_index + REFCOUNTS_PER_SECTOR)
- & ~(REFCOUNTS_PER_SECTOR - 1);
-
- size = (last_index - first_index) << REFCOUNT_SHIFT;
-
- BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE_PART);
- ret = bdrv_pwrite(bs->file,
- refcount_block_offset + (first_index << REFCOUNT_SHIFT),
- &s->refcount_block_cache[first_index], size);
- if (ret < 0) {
- return ret;
- }
-
- return 0;
+ return ret;
}
/* XXX: cache several refcount block clusters ? */
@@ -463,9 +418,7 @@ static int QEMU_WARN_UNUSED_RESULT
update_refcount(BlockDriverState *bs,
{
BDRVQcowState *s = bs->opaque;
int64_t start, last, cluster_offset;
- int64_t refcount_block_offset = 0;
- int64_t table_index = -1, old_table_index;
- int first_index = -1, last_index = -1;
+ uint16_t *refcount_block = NULL;
int ret;
#ifdef DEBUG_ALLOC2
@@ -478,6 +431,11 @@ static int QEMU_WARN_UNUSED_RESULT
update_refcount(BlockDriverState *bs,
return 0;
}
+ if (addend < 0) {
+ qcow2_cache_set_dependency(bs, s->refcount_block_cache,
+ s->l2_table_cache);
+ }
+
start = offset & ~(s->cluster_size - 1);
last = (offset + length - 1) & ~(s->cluster_size - 1);
for(cluster_offset = start; cluster_offset <= last;
@@ -485,42 +443,26 @@ static int QEMU_WARN_UNUSED_RESULT
update_refcount(BlockDriverState *bs,
{
int block_index, refcount;
int64_t cluster_index = cluster_offset >> s->cluster_bits;
- int64_t new_block;
- /* Only write refcount block to disk when we are done with it */
- old_table_index = table_index;
- table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
- if ((old_table_index >= 0) && (table_index != old_table_index)) {
-
- ret = write_refcount_block_entries(bs, refcount_block_offset,
- first_index, last_index);
+ /* Load the refcount block and allocate it if needed */
+ if (refcount_block) {
+ ret = qcow2_cache_put(bs, s->refcount_block_cache, refcount_block);
if (ret < 0) {
- return ret;
+ goto fail;
}
-
- first_index = -1;
- last_index = -1;
}
- /* Load the refcount block and allocate it if needed */
- new_block = alloc_refcount_block(bs, cluster_index);
- if (new_block < 0) {
- ret = new_block;
+ ret = alloc_refcount_block(bs, cluster_index, &refcount_block);
+ if (ret < 0) {
goto fail;
}
- refcount_block_offset = new_block;
+ qcow2_cache_entry_mark_dirty(s->refcount_block_cache, refcount_block);
/* we can update the count and save it */
block_index = cluster_index &
((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
- if (first_index == -1 || block_index < first_index) {
- first_index = block_index;
- }
- if (block_index > last_index) {
- last_index = block_index;
- }
- refcount = be16_to_cpu(s->refcount_block_cache[block_index]);
+ refcount = be16_to_cpu(refcount_block[block_index]);
refcount += addend;
if (refcount < 0 || refcount > 0xffff) {
ret = -EINVAL;
@@ -529,17 +471,15 @@ static int QEMU_WARN_UNUSED_RESULT
update_refcount(BlockDriverState *bs,
if (refcount == 0 && cluster_index < s->free_cluster_index) {
s->free_cluster_index = cluster_index;
}
- s->refcount_block_cache[block_index] = cpu_to_be16(refcount);
+ refcount_block[block_index] = cpu_to_be16(refcount);
}
ret = 0;
fail:
-
/* Write last changed block to disk */
- if (refcount_block_offset != 0) {
+ if (refcount_block) {
int wret;
- wret = write_refcount_block_entries(bs, refcount_block_offset,
- first_index, last_index);
+ wret = qcow2_cache_put(bs, s->refcount_block_cache, refcount_block);
if (wret < 0) {
return ret < 0 ? ret : wret;
}
@@ -758,9 +698,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated;
int64_t old_offset, old_l2_offset;
int l2_size, i, j, l1_modified, l2_modified, nb_csectors, refcount;
-
- qcow2_l2_cache_reset(bs);
- cache_refcount_updates = 1;
+ int ret;
l2_table = NULL;
l1_table = NULL;
@@ -784,7 +722,6 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
}
l2_size = s->l2_size * sizeof(uint64_t);
- l2_table = qemu_malloc(l2_size);
l1_modified = 0;
for(i = 0; i < l1_size; i++) {
l2_offset = l1_table[i];
@@ -792,8 +729,13 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
old_l2_offset = l2_offset;
l2_offset &= ~QCOW_OFLAG_COPIED;
l2_modified = 0;
- if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size)
+
+ ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset,
+ (void**) &l2_table);
+ if (ret < 0) {
goto fail;
+ }
+
for(j = 0; j < s->l2_size; j++) {
offset = be64_to_cpu(l2_table[j]);
if (offset != 0) {
@@ -833,17 +775,24 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
offset |= QCOW_OFLAG_COPIED;
}
if (offset != old_offset) {
+ if (addend > 0) {
+ qcow2_cache_set_dependency(bs, s->l2_table_cache,
+ s->refcount_block_cache);
+ }
l2_table[j] = cpu_to_be64(offset);
l2_modified = 1;
+ qcow2_cache_entry_mark_dirty(s->l2_table_cache,
l2_table);
}
}
}
- if (l2_modified) {
- if (bdrv_pwrite_sync(bs->file,
- l2_offset, l2_table, l2_size) < 0)
- goto fail;
+
+ ret = qcow2_cache_put(bs, s->l2_table_cache, l2_table);
+ if (ret < 0) {
+ goto fail;
}
+ l2_table = NULL;
+
if (addend != 0) {
refcount = update_cluster_refcount(bs, l2_offset >>
s->cluster_bits, addend);
} else {
@@ -871,16 +820,14 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
}
if (l1_allocated)
qemu_free(l1_table);
- qemu_free(l2_table);
- cache_refcount_updates = 0;
- write_refcount_block(bs);
return 0;
fail:
+ if (l2_table) {
+ qcow2_cache_put(bs, s->l2_table_cache, l2_table);
+ }
+
if (l1_allocated)
qemu_free(l1_table);
- qemu_free(l2_table);
- cache_refcount_updates = 0;
- write_refcount_block(bs);
return -EIO;
}
diff --git a/block/qcow2.c b/block/qcow2.c
index b6b094c..299ef38 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -143,6 +143,7 @@ static int qcow2_open(BlockDriverState *bs, int flags)
int len, i, ret = 0;
QCowHeader header;
uint64_t ext_end;
+ bool writethrough;
ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
if (ret < 0) {
@@ -217,8 +218,13 @@ static int qcow2_open(BlockDriverState *bs, int flags)
be64_to_cpus(&s->l1_table[i]);
}
}
- /* alloc L2 cache */
- s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
+
+ /* alloc L2 table/refcount block cache */
+ writethrough = ((flags & BDRV_O_CACHE_MASK) == 0);
+ s->l2_table_cache = qcow2_cache_create(bs, L2_CACHE_SIZE, writethrough);
+ s->refcount_block_cache = qcow2_cache_create(bs, REFCOUNT_CACHE_SIZE,
+ writethrough);
+
s->cluster_cache = qemu_malloc(s->cluster_size);
/* one more sector for decompressed data alignment */
s->cluster_data = qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
@@ -270,7 +276,9 @@ static int qcow2_open(BlockDriverState *bs, int flags)
qcow2_free_snapshots(bs);
qcow2_refcount_close(bs);
qemu_free(s->l1_table);
- qemu_free(s->l2_cache);
+ if (s->l2_table_cache) {
+ qcow2_cache_destroy(bs, s->l2_table_cache);
+ }
qemu_free(s->cluster_cache);
qemu_free(s->cluster_data);
return ret;
@@ -719,7 +727,8 @@ static void qcow2_close(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
qemu_free(s->l1_table);
- qemu_free(s->l2_cache);
+ qcow2_cache_destroy(bs, s->l2_table_cache);
+ qcow2_cache_destroy(bs, s->refcount_block_cache);
qemu_free(s->cluster_cache);
qemu_free(s->cluster_data);
qcow2_refcount_close(bs);
@@ -1179,6 +1188,19 @@ static int qcow2_write_compressed(BlockDriverState *bs,
int64_t sector_num,
static int qcow2_flush(BlockDriverState *bs)
{
+ BDRVQcowState *s = bs->opaque;
+ int ret;
+
+ ret = qcow2_cache_flush(bs, s->l2_table_cache);
+ if (ret < 0) {
+ return ret;
+ }
+
+ ret = qcow2_cache_flush(bs, s->refcount_block_cache);
+ if (ret < 0) {
+ return ret;
+ }
+
return bdrv_flush(bs->file);
}
@@ -1186,6 +1208,19 @@ static BlockDriverAIOCB
*qcow2_aio_flush(BlockDriverState *bs,
BlockDriverCompletionFunc *cb,
void *opaque)
{
+ BDRVQcowState *s = bs->opaque;
+ int ret;
+
+ ret = qcow2_cache_flush(bs, s->l2_table_cache);
+ if (ret < 0) {
+ return NULL;
+ }
+
+ ret = qcow2_cache_flush(bs, s->refcount_block_cache);
+ if (ret < 0) {
+ return NULL;
+ }
+
return bdrv_aio_flush(bs->file, cb, opaque);
}
diff --git a/block/qcow2.h b/block/qcow2.h
index 81d4853..fc6a96b 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -51,6 +51,9 @@
#define L2_CACHE_SIZE 16
+/* Must be at least 4 to cover all cases of refcount table growth */
+#define REFCOUNT_CACHE_SIZE 4
+
typedef struct QCowHeader {
uint32_t magic;
uint32_t version;
@@ -94,9 +97,10 @@ typedef struct BDRVQcowState {
uint64_t cluster_offset_mask;
uint64_t l1_table_offset;
uint64_t *l1_table;
- uint64_t *l2_cache;
- uint64_t l2_cache_offsets[L2_CACHE_SIZE];
- uint32_t l2_cache_counts[L2_CACHE_SIZE];
+
+ QcowCache* l2_table_cache;
+ QcowCache* refcount_block_cache;
+
uint8_t *cluster_cache;
uint8_t *cluster_data;
uint64_t cluster_cache_offset;
@@ -105,8 +109,6 @@ typedef struct BDRVQcowState {
uint64_t *refcount_table;
uint64_t refcount_table_offset;
uint32_t refcount_table_size;
- uint64_t refcount_block_cache_offset;
- uint16_t *refcount_block_cache;
int64_t free_cluster_index;
int64_t free_byte_offset;
--
1.7.2.3