diff options
author | Paolo Bonzini <pbonzini@redhat.com> | 2012-06-06 00:04:55 +0200 |
---|---|---|
committer | Kevin Wolf <kwolf@redhat.com> | 2012-06-15 14:03:43 +0200 |
commit | 6af4e9ead4ec9491259c9861b1b35f9abee24a66 (patch) | |
tree | e73675471adb5001272bbfcbab116da8d8acf829 /block | |
parent | 7cdd481cdf15d610f83e38f15c7e7979420c6ac0 (diff) | |
download | hqemu-6af4e9ead4ec9491259c9861b1b35f9abee24a66.zip hqemu-6af4e9ead4ec9491259c9861b1b35f9abee24a66.tar.gz |
qcow2: always operate caches in writeback mode
Writethrough does not need special-casing anymore in the qcow2 caches.
The block layer adds flushes after every guest-initiated data write,
and these will also flush the qcow2 caches to the OS.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block')
-rw-r--r-- | block/qcow2-cache.c | 25 | ||||
-rw-r--r-- | block/qcow2-refcount.c | 12 | ||||
-rw-r--r-- | block/qcow2.c | 7 | ||||
-rw-r--r-- | block/qcow2.h | 5 |
4 files changed, 5 insertions, 44 deletions
diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c index 710d4b1..2d4322a 100644 --- a/block/qcow2-cache.c +++ b/block/qcow2-cache.c @@ -40,11 +40,9 @@ struct Qcow2Cache { struct Qcow2Cache* depends; int size; bool depends_on_flush; - bool writethrough; }; -Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables, - bool writethrough) +Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables) { BDRVQcowState *s = bs->opaque; Qcow2Cache *c; @@ -53,7 +51,6 @@ Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables, c = g_malloc0(sizeof(*c)); c->size = num_tables; c->entries = g_malloc0(sizeof(*c->entries) * num_tables); - c->writethrough = writethrough; for (i = 0; i < c->size; i++) { c->entries[i].table = qemu_blockalign(bs, s->cluster_size); @@ -307,12 +304,7 @@ found: *table = NULL; assert(c->entries[i].ref >= 0); - - if (c->writethrough) { - return qcow2_cache_entry_flush(bs, c, i); - } else { - return 0; - } + return 0; } void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table) @@ -329,16 +321,3 @@ void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table) found: c->entries[i].dirty = true; } - -bool qcow2_cache_set_writethrough(BlockDriverState *bs, Qcow2Cache *c, - bool enable) -{ - bool old = c->writethrough; - - if (!old && enable) { - qcow2_cache_flush(bs, c); - } - - c->writethrough = enable; - return old; -} diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 5d6ea72..66f3915 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -726,13 +726,6 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, int64_t old_offset, old_l2_offset; int i, j, l1_modified = 0, nb_csectors, refcount; int ret; - bool old_l2_writethrough, old_refcount_writethrough; - - /* Switch caches to writeback mode during update */ - old_l2_writethrough = - qcow2_cache_set_writethrough(bs, s->l2_table_cache, false); - old_refcount_writethrough = - qcow2_cache_set_writethrough(bs, s->refcount_block_cache, false); l2_table = NULL; l1_table = NULL; @@ -856,11 +849,6 @@ fail: qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); } - /* Enable writethrough cache mode again */ - qcow2_cache_set_writethrough(bs, s->l2_table_cache, old_l2_writethrough); - qcow2_cache_set_writethrough(bs, s->refcount_block_cache, - old_refcount_writethrough); - /* Update L1 only if it isn't deleted anyway (addend = -1) */ if (addend >= 0 && l1_modified) { for(i = 0; i < l1_size; i++) diff --git a/block/qcow2.c b/block/qcow2.c index d66de58..57fd43d 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -220,7 +220,6 @@ 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) { @@ -367,10 +366,8 @@ static int qcow2_open(BlockDriverState *bs, int flags) } /* alloc L2 table/refcount block cache */ - writethrough = ((flags & BDRV_O_CACHE_WB) == 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->l2_table_cache = qcow2_cache_create(bs, L2_CACHE_SIZE); + s->refcount_block_cache = qcow2_cache_create(bs, REFCOUNT_CACHE_SIZE); s->cluster_cache = g_malloc(s->cluster_size); /* one more sector for decompressed data alignment */ diff --git a/block/qcow2.h b/block/qcow2.h index c6e7237..455b6d7 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -297,11 +297,8 @@ void qcow2_free_snapshots(BlockDriverState *bs); int qcow2_read_snapshots(BlockDriverState *bs); /* qcow2-cache.c functions */ -Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables, - bool writethrough); +Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables); int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c); -bool qcow2_cache_set_writethrough(BlockDriverState *bs, Qcow2Cache *c, - bool enable); void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table); int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c); |