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qed: add bdrv_qed_copy_header()

PATCH In review Devin Nakamura 2 participants 2 messages Sep 12, 2011 – Sep 20, 2011 Block layer

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Devin Nakamura

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#0 lore raw

PATCH 6/6 qed: add bdrv_qed_copy_header()

Signed-off-by Devin Nakamura <[email protected]>
---
 block/qed.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)
block/qed.c +15 -0
index 341cf9d..caecdff 100644
@@ -1586,6 +1586,20 @@ static int bdrv_qed_map(BlockDriverState *bs, uint64_t guest_offset,
     return 0;
 }
 
+static int bdrv_qed_copy_header(BlockDriverState *bs, char* filename)
+{
+    BlockDriverState *backup;
+    uint8_t buffer[512];
+    bdrv_create_file(filename, NULL);
+    bdrv_file_open(&backup, filename, BDRV_O_RDWR);
+    bdrv_read(bs->file, 0, buffer, 1); /*TODO: check return code*/
+    bdrv_write(backup, 0, buffer, 1); /*TODO: check return code*/
+    bdrv_close(backup);
+
+    qed_write_header_sync(bs->opaque);
+    return 0;
+}
+
 static QEMUOptionParameter qed_create_options[] = {
     {
         .name = BLOCK_OPT_SIZE,

@@ -1636,6 +1650,7 @@ static BlockDriver bdrv_qed = {
     .bdrv_open_conversion_target = bdrv_qed_open_conversion_target,
     .bdrv_get_mapping         = bdrv_qed_get_mapping,
     .bdrv_map                 = bdrv_qed_map,
+    .bdrv_copy_header            = bdrv_qed_copy_header,
 };
 
 static void bdrv_qed_init(void)
Signature · 1 line
1.7.6.rc1
#1 lore raw

Am 12.09.2011 16:59, schrieb Devin Nakamura:

Quoted 11 lines
Signed-off-by Devin Nakamura <[email protected]>
---
 block/qed.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)
block/qed.c +0 -0
index 341cf9d..caecdff 100644
@@ -1586,6 +1586,20 @@ static int bdrv_qed_map(BlockDriverState *bs, uint64_t guest_offset,
     return 0;

block/qed.c static int bdrv_qed_map(BlockDriverState *bs, uint64_t guest_offset, · line 1596

Quoted 10 lines
block/qed.c +8 -0
 }
 
+static int bdrv_qed_copy_header(BlockDriverState *bs, char* filename)
+{
+    BlockDriverState *backup;
+    uint8_t buffer[512];
+    bdrv_create_file(filename, NULL);
+    bdrv_file_open(&backup, filename, BDRV_O_RDWR);
+    bdrv_read(bs->file, 0, buffer, 1); /*TODO: check return code*/
+    bdrv_write(backup, 0, buffer, 1); /*TODO: check return code*/

Come on, checking return values isn't much more work than adding a TODO comment.

block/qed.c static int bdrv_qed_map(BlockDriverState *bs, uint64_t guest_offset, · line 1601

Quoted 5 lines
block/qed.c +5 -0
+    bdrv_close(backup);
+
+    qed_write_header_sync(bs->opaque);
+    return 0;
+}

This is probably right, but it makes me wonder if we are sure that QED never tries to write out the header before bdrv_qed_copy_header() is called? In that case we would have destroyed the original format before completing the conversion.

I would feel more comfortable if BDRVQEDState had a field header_offset that would be set to a temporary location by bdrv_qed_open_conversion_target and reset to 0 by bdrv_qed_copy_header.

Kevin