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[Qemu-devel] [PATCH 08/26] qcow2: Fix creation of large images
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 08/26] qcow2: Fix creation of large images |
Date: |
Fri, 23 Apr 2010 17:30:40 +0200 |
qcow_create2 assumes that the new image will only need one cluster for its
refcount table initially. Obviously that's not true any more when the image is
big enough (exact value depends on the cluster size).
This patch calculates the refcount table size dynamically.
Signed-off-by: Kevin Wolf <address@hidden>
---
block/qcow2.c | 43 +++++++++++++++++++++++++++++++++----------
1 files changed, 33 insertions(+), 10 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 80c99af..67affa6 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -850,10 +850,11 @@ static int qcow_create2(const char *filename, int64_t
total_size,
{
int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits;
- int ref_clusters, backing_format_len = 0;
+ int ref_clusters, reftable_clusters, backing_format_len = 0;
int rounded_ext_bf_len = 0;
QCowHeader header;
uint64_t tmp, offset;
+ uint64_t old_ref_clusters;
QCowCreateState s1, *s = &s1;
QCowExtension ext_bf = {0, 0};
int ret;
@@ -912,17 +913,37 @@ static int qcow_create2(const char *filename, int64_t
total_size,
header.l1_size = cpu_to_be32(l1_size);
offset += align_offset(l1_size * sizeof(uint64_t), s->cluster_size);
- s->refcount_table = qemu_mallocz(s->cluster_size);
+ /* count how many refcount blocks needed */
+
+#define NUM_CLUSTERS(bytes) \
+ (((bytes) + (s->cluster_size) - 1) / (s->cluster_size))
+
+ ref_clusters = NUM_CLUSTERS(NUM_CLUSTERS(offset) * sizeof(uint16_t));
+
+ do {
+ uint64_t image_clusters;
+ old_ref_clusters = ref_clusters;
+
+ /* Number of clusters used for the refcount table */
+ reftable_clusters = NUM_CLUSTERS(ref_clusters * sizeof(uint64_t));
+
+ /* Number of clusters that the whole image will have */
+ image_clusters = NUM_CLUSTERS(offset) + ref_clusters
+ + reftable_clusters;
+
+ /* Number of refcount blocks needed for the image */
+ ref_clusters = NUM_CLUSTERS(image_clusters * sizeof(uint16_t));
+
+ } while (ref_clusters != old_ref_clusters);
+
+ s->refcount_table = qemu_mallocz(reftable_clusters * s->cluster_size);
s->refcount_table_offset = offset;
header.refcount_table_offset = cpu_to_be64(offset);
- header.refcount_table_clusters = cpu_to_be32(1);
- offset += s->cluster_size;
+ header.refcount_table_clusters = cpu_to_be32(reftable_clusters);
+ offset += (reftable_clusters * s->cluster_size);
s->refcount_block_offset = offset;
- /* count how many refcount blocks needed */
- tmp = offset >> s->cluster_bits;
- ref_clusters = (tmp >> (s->cluster_bits - REFCOUNT_SHIFT)) + 1;
for (i=0; i < ref_clusters; i++) {
s->refcount_table[i] = cpu_to_be64(offset);
offset += s->cluster_size;
@@ -934,7 +955,8 @@ static int qcow_create2(const char *filename, int64_t
total_size,
qcow2_create_refcount_update(s, 0, header_size);
qcow2_create_refcount_update(s, s->l1_table_offset,
l1_size * sizeof(uint64_t));
- qcow2_create_refcount_update(s, s->refcount_table_offset, s->cluster_size);
+ qcow2_create_refcount_update(s, s->refcount_table_offset,
+ reftable_clusters * s->cluster_size);
qcow2_create_refcount_update(s, s->refcount_block_offset,
ref_clusters * s->cluster_size);
@@ -986,8 +1008,9 @@ static int qcow_create2(const char *filename, int64_t
total_size,
}
}
lseek(fd, s->refcount_table_offset, SEEK_SET);
- ret = qemu_write_full(fd, s->refcount_table, s->cluster_size);
- if (ret != s->cluster_size) {
+ ret = qemu_write_full(fd, s->refcount_table,
+ reftable_clusters * s->cluster_size);
+ if (ret != reftable_clusters * s->cluster_size) {
ret = -errno;
goto exit;
}
--
1.6.6.1
- [Qemu-devel] [PULL 00/26] Block patches, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 01/26] qemu-config: qemu_read_config_file() reads the normal config file, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 02/26] qemu-config: Make qemu_config_parse more generic, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 04/26] blkdebug: Inject errors, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 03/26] blkdebug: Basic request passthrough, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 05/26] Make qemu-config available for tools, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 06/26] blkdebug: Add events and rules, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 08/26] qcow2: Fix creation of large images,
Kevin Wolf <=
- [Qemu-devel] [PATCH 09/26] Replace calls of old bdrv_open, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 13/26] qcow2: Fix error return code in qcow2_alloc_cluster_link_l2, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 10/26] block: get rid of the BDRV_O_FILE flag, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 12/26] qcow2: Return 0/-errno in write_l2_entries, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 07/26] qcow2: Trigger blkdebug events, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 11/26] block: split raw_getlength, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 15/26] qcow2: Return 0/-errno in l2_allocate, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 14/26] qcow2: Return 0/-errno in write_l1_entry, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 17/26] block: Do not export bdrv_first, Kevin Wolf, 2010/04/23
- [Qemu-devel] [PATCH 16/26] cleanup block driver option handling in vl.c, Kevin Wolf, 2010/04/23