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[Qemu-devel] [PATCH 2/5] block/vpc: simplify vpc_read
From: |
Peter Lieven |
Subject: |
[Qemu-devel] [PATCH 2/5] block/vpc: simplify vpc_read |
Date: |
Mon, 23 Feb 2015 15:27:38 +0100 |
Signed-off-by: Peter Lieven <address@hidden>
---
block/vpc.c | 116 +++++++++++++++++++++++++++--------------------------------
1 file changed, 52 insertions(+), 64 deletions(-)
diff --git a/block/vpc.c b/block/vpc.c
index 326c2bb..4e5ba85 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -497,40 +497,70 @@ static int vpc_get_info(BlockDriverState *bs,
BlockDriverInfo *bdi)
return 0;
}
-static int vpc_read(BlockDriverState *bs, int64_t sector_num,
- uint8_t *buf, int nb_sectors)
+static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, int *pnum)
{
BDRVVPCState *s = bs->opaque;
- int ret;
- int64_t offset;
- int64_t sectors, sectors_per_block;
- VHDFooter *footer = (VHDFooter *) s->footer_buf;
+ VHDFooter *footer = (VHDFooter*) s->footer_buf;
+ int64_t start, offset;
+ bool allocated;
+ int n;
if (be32_to_cpu(footer->type) == VHD_FIXED) {
- return bdrv_read(bs->file, sector_num, buf, nb_sectors);
+ *pnum = nb_sectors;
+ return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
+ (sector_num << BDRV_SECTOR_BITS);
}
- while (nb_sectors > 0) {
- offset = get_sector_offset(bs, sector_num, 0);
- sectors_per_block = s->block_size >> BDRV_SECTOR_BITS;
- sectors = sectors_per_block - (sector_num % sectors_per_block);
- if (sectors > nb_sectors) {
- sectors = nb_sectors;
+ offset = get_sector_offset(bs, sector_num, 0);
+ start = offset;
+ allocated = (offset != -1);
+ *pnum = 0;
+
+ do {
+ /* All sectors in a block are contiguous (without using the bitmap) */
+ n = ROUND_UP(sector_num + 1, s->block_size / BDRV_SECTOR_SIZE)
+ - sector_num;
+ n = MIN(n, nb_sectors);
+
+ *pnum += n;
+ sector_num += n;
+ nb_sectors -= n;
+
+ if (allocated) {
+ return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | start;
}
+ if (nb_sectors == 0) {
+ break;
+ }
+ offset = get_sector_offset(bs, sector_num, 0);
+ } while (offset == -1);
- if (offset == -1) {
- memset(buf, 0, sectors * BDRV_SECTOR_SIZE);
- } else {
- ret = bdrv_pread(bs->file, offset, buf,
- sectors * BDRV_SECTOR_SIZE);
- if (ret != sectors * BDRV_SECTOR_SIZE) {
+ return 0;
+}
+
+static int vpc_read(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
+{
+ int ret, n;
+ int64_t ret2;
+
+ while (nb_sectors > 0) {
+ ret2 = vpc_co_get_block_status(bs, sector_num, nb_sectors, &n);
+
+ if (ret2 & BDRV_BLOCK_OFFSET_VALID) {
+ ret = bdrv_pread(bs->file, ret2 & BDRV_SECTOR_MASK, buf,
+ n * BDRV_SECTOR_SIZE);
+ if (ret != n * BDRV_SECTOR_SIZE) {
return -1;
}
+ } else {
+ memset(buf, 0x00, n * BDRV_SECTOR_SIZE);
}
- nb_sectors -= sectors;
- sector_num += sectors;
- buf += sectors * BDRV_SECTOR_SIZE;
+ sector_num += n;
+ nb_sectors -= n;
+ buf += n * BDRV_SECTOR_SIZE;
}
return 0;
}
@@ -597,48 +627,6 @@ static coroutine_fn int vpc_co_write(BlockDriverState *bs,
int64_t sector_num,
return ret;
}
-static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
- int64_t sector_num, int nb_sectors, int *pnum)
-{
- BDRVVPCState *s = bs->opaque;
- VHDFooter *footer = (VHDFooter*) s->footer_buf;
- int64_t start, offset;
- bool allocated;
- int n;
-
- if (be32_to_cpu(footer->type) == VHD_FIXED) {
- *pnum = nb_sectors;
- return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
- (sector_num << BDRV_SECTOR_BITS);
- }
-
- offset = get_sector_offset(bs, sector_num, 0);
- start = offset;
- allocated = (offset != -1);
- *pnum = 0;
-
- do {
- /* All sectors in a block are contiguous (without using the bitmap) */
- n = ROUND_UP(sector_num + 1, s->block_size / BDRV_SECTOR_SIZE)
- - sector_num;
- n = MIN(n, nb_sectors);
-
- *pnum += n;
- sector_num += n;
- nb_sectors -= n;
-
- if (allocated) {
- return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | start;
- }
- if (nb_sectors == 0) {
- break;
- }
- offset = get_sector_offset(bs, sector_num, 0);
- } while (offset == -1);
-
- return 0;
-}
-
/*
* Calculates the number of cylinders, heads and sectors per cylinder
* based on a given number of sectors. This is the algorithm described
--
1.7.9.5