From e9029068354e2c9dbfe7e7deaa6a96344a8b4d46 Mon Sep 17 00:00:00 2001
From: Jeffrey Cody <jcody@redhat.com>
Date: Wed, 20 Nov 2013 19:44:03 +0100
Subject: [PATCH 20/25] block: vhdx - break out code operations to functions
RH-Author: Jeffrey Cody <jcody@redhat.com>
Message-id: <7f3a67c6c0988ecccac88cc5a8985058611e4cfa.1384975172.git.jcody@redhat.com>
Patchwork-id: 55815
O-Subject: [RHEL7 qemu-kvm PATCH 20/26] block: vhdx - break out code operations to functions
Bugzilla: 879234
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>
This is preperation for vhdx_create(). The ability to write headers,
and calculate the number of BAT entries will be needed within the
create() functions, so move this relevant code into helper functions.
Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 1e74a971cb3229813112c74dca81e599812b66f3)
---
block/vhdx.c | 121 +++++++++++++++++++++++++++++++++++++++--------------------
1 file changed, 80 insertions(+), 41 deletions(-)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
block/vhdx.c | 121 ++++++++++++++++++++++++++++++++++++++--------------------
1 files changed, 80 insertions(+), 41 deletions(-)
diff --git a/block/vhdx.c b/block/vhdx.c
index 9d51176..5a112e8 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -248,6 +248,14 @@ static void vhdx_region_unregister_all(BDRVVHDXState *s)
}
}
+static void vhdx_set_shift_bits(BDRVVHDXState *s)
+{
+ s->logical_sector_size_bits = 31 - clz32(s->logical_sector_size);
+ s->sectors_per_block_bits = 31 - clz32(s->sectors_per_block);
+ s->chunk_ratio_bits = 63 - clz64(s->chunk_ratio);
+ s->block_size_bits = 31 - clz32(s->block_size);
+}
+
/*
* Per the MS VHDX Specification, for every VHDX file:
* - The header section is fixed size - 1 MB
@@ -267,6 +275,50 @@ static int vhdx_probe(const uint8_t *buf, int buf_size, const char *filename)
return 0;
}
+/*
+ * Writes the header to the specified offset.
+ *
+ * This will optionally read in buffer data from disk (otherwise zero-fill),
+ * and then update the header checksum. Header is converted to proper
+ * endianness before being written to the specified file offset
+ */
+static int vhdx_write_header(BlockDriverState *bs_file, VHDXHeader *hdr,
+ uint64_t offset, bool read)
+{
+ uint8_t *buffer = NULL;
+ int ret;
+ VHDXHeader header_le;
+
+ assert(bs_file != NULL);
+ assert(hdr != NULL);
+
+ /* the header checksum is not over just the packed size of VHDXHeader,
+ * but rather over the entire 'reserved' range for the header, which is
+ * 4KB (VHDX_HEADER_SIZE). */
+
+ buffer = qemu_blockalign(bs_file, VHDX_HEADER_SIZE);
+ if (read) {
+ /* if true, we can't assume the extra reserved bytes are 0 */
+ ret = bdrv_pread(bs_file, offset, buffer, VHDX_HEADER_SIZE);
+ if (ret < 0) {
+ goto exit;
+ }
+ } else {
+ memset(buffer, 0, VHDX_HEADER_SIZE);
+ }
+
+ /* overwrite the actual VHDXHeader portion */
+ memcpy(buffer, hdr, sizeof(VHDXHeader));
+ hdr->checksum = vhdx_update_checksum(buffer, VHDX_HEADER_SIZE,
+ offsetof(VHDXHeader, checksum));
+ vhdx_header_le_export(hdr, &header_le);
+ ret = bdrv_pwrite_sync(bs_file, offset, &header_le, sizeof(VHDXHeader));
+
+exit:
+ qemu_vfree(buffer);
+ return ret;
+}
+
/* Update the VHDX headers
*
* This follows the VHDX spec procedures for header updates.
@@ -282,8 +334,6 @@ static int vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s,
VHDXHeader *active_header;
VHDXHeader *inactive_header;
- VHDXHeader header_le;
- uint8_t *buffer;
/* operate on the non-current header */
if (s->curr_header == 0) {
@@ -311,31 +361,13 @@ static int vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s,
inactive_header->log_guid = *log_guid;
}
- /* the header checksum is not over just the packed size of VHDXHeader,
- * but rather over the entire 'reserved' range for the header, which is
- * 4KB (VHDX_HEADER_SIZE). */
-
- buffer = qemu_blockalign(bs, VHDX_HEADER_SIZE);
- /* we can't assume the extra reserved bytes are 0 */
- ret = bdrv_pread(bs->file, header_offset, buffer, VHDX_HEADER_SIZE);
- if (ret < 0) {
- goto exit;
- }
- /* overwrite the actual VHDXHeader portion */
- memcpy(buffer, inactive_header, sizeof(VHDXHeader));
- inactive_header->checksum =
- vhdx_update_checksum(buffer, VHDX_HEADER_SIZE,
- offsetof(VHDXHeader, checksum));
- vhdx_header_le_export(inactive_header, &header_le);
- ret = bdrv_pwrite_sync(bs->file, header_offset, &header_le,
- sizeof(VHDXHeader));
+ vhdx_write_header(bs->file, inactive_header, header_offset, true);
if (ret < 0) {
goto exit;
}
s->curr_header = hdr_idx;
exit:
- qemu_vfree(buffer);
return ret;
}
@@ -773,10 +805,7 @@ static int vhdx_parse_metadata(BlockDriverState *bs, BDRVVHDXState *s)
goto exit;
}
- s->logical_sector_size_bits = 31 - clz32(s->logical_sector_size);
- s->sectors_per_block_bits = 31 - clz32(s->sectors_per_block);
- s->chunk_ratio_bits = 63 - clz64(s->chunk_ratio);
- s->block_size_bits = 31 - clz32(s->block_size);
+ vhdx_set_shift_bits(s);
ret = 0;
@@ -785,6 +814,31 @@ exit:
return ret;
}
+/*
+ * Calculate the number of BAT entries, including sector
+ * bitmap entries.
+ */
+static void vhdx_calc_bat_entries(BDRVVHDXState *s)
+{
+ uint32_t data_blocks_cnt, bitmap_blocks_cnt;
+
+ data_blocks_cnt = s->virtual_disk_size >> s->block_size_bits;
+ if (s->virtual_disk_size - (data_blocks_cnt << s->block_size_bits)) {
+ data_blocks_cnt++;
+ }
+ bitmap_blocks_cnt = data_blocks_cnt >> s->chunk_ratio_bits;
+ if (data_blocks_cnt - (bitmap_blocks_cnt << s->chunk_ratio_bits)) {
+ bitmap_blocks_cnt++;
+ }
+
+ if (s->parent_entries) {
+ s->bat_entries = bitmap_blocks_cnt * (s->chunk_ratio + 1);
+ } else {
+ s->bat_entries = data_blocks_cnt +
+ ((data_blocks_cnt - 1) >> s->chunk_ratio_bits);
+ }
+
+}
static void vhdx_close(BlockDriverState *bs)
{
@@ -811,7 +865,6 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
int ret = 0;
uint32_t i;
uint64_t signature;
- uint32_t data_blocks_cnt, bitmap_blocks_cnt;
bool log_flushed = false;
@@ -862,21 +915,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
* logical_sector_size */
bs->total_sectors = s->virtual_disk_size >> s->logical_sector_size_bits;
- data_blocks_cnt = s->virtual_disk_size >> s->block_size_bits;
- if (s->virtual_disk_size - (data_blocks_cnt << s->block_size_bits)) {
- data_blocks_cnt++;
- }
- bitmap_blocks_cnt = data_blocks_cnt >> s->chunk_ratio_bits;
- if (data_blocks_cnt - (bitmap_blocks_cnt << s->chunk_ratio_bits)) {
- bitmap_blocks_cnt++;
- }
-
- if (s->parent_entries) {
- s->bat_entries = bitmap_blocks_cnt * (s->chunk_ratio + 1);
- } else {
- s->bat_entries = data_blocks_cnt +
- ((data_blocks_cnt - 1) >> s->chunk_ratio_bits);
- }
+ vhdx_calc_bat_entries(s);
s->bat_offset = s->bat_rt.file_offset;
--
1.7.1