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Re: [Qemu-devel] [PATCH] block: Add support for vpc Fixed Disk type
|
From: |
Andreas Färber |
|
Subject: |
Re: [Qemu-devel] [PATCH] block: Add support for vpc Fixed Disk type |
|
Date: |
Tue, 31 Jan 2012 23:08:25 +0100 |
|
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111220 Thunderbird/9.0 |
Hello Charles,
Am 31.01.2012 20:03, schrieb Charles Arnold:
> The Virtual Hard Disk Image Format Specification allows for three
> types of hard disk formats, Fixed, Dynamic, and Differencing. Qemu
> currently only supports Dynamic disks. This patch adds support for
> the Fixed Disk format.
>
> Usage:
> Example 1: qemu-img create -f vpc -o type=fixed <filename> [size]
> Example 2: qemu-img convert -O vpc -o type=fixed <input filename> <output
> filename>
>
> While it is also allowed to specify '-o type=dynamic', the default disk type
> remains Dynamic and is what is used when the type is left unspecified.
>
> Signed-off-by: Charles Arnold <address@hidden>
Please cc the block maintainer. If --cc-cmd=scripts/get_maintainer.pl
doesn't pick him up please let us know so that we can fix that.
Many Coding Style issues (most probably from the duplicated code?), two
32-bit issues, otherwise looks okay.
The patch itself arrived with lots of trailing whitespace in some places
though.
Please run scripts/checkpatch.pl. That should notify you of most issues
noted below before submitting, see for instance:
http://blog.vmsplice.net/2011/03/how-to-automatically-run-checkpatchpl.html
> diff --git a/block/vpc.c b/block/vpc.c
> index 89a5ee2..bfe5f7b 100644
> --- a/block/vpc.c
> +++ b/block/vpc.c
> @@ -160,6 +160,7 @@ static int vpc_open(BlockDriverState *bs, int flags)
> struct vhd_dyndisk_header* dyndisk_header;
> uint8_t buf[HEADER_SIZE];
> uint32_t checksum;
> + int disk_type = VHD_DYNAMIC;
> int err = -1;
>
> if (bdrv_pread(bs->file, 0, s->footer_buf, HEADER_SIZE) != HEADER_SIZE)
> @@ -167,7 +168,16 @@ static int vpc_open(BlockDriverState *bs, int flags)
>
> footer = (struct vhd_footer*) s->footer_buf;
> if (strncmp(footer->creator, "conectix", 8))
> - goto fail;
> + {
Brace on the previous line please.
> + int64_t offset = bdrv_getlength(bs->file);
> + // If a fixed disk, the footer is found only at the end of the file
Please use ANSI C comments /* ... */ exclusively.
> + if (bdrv_pread(bs->file, offset-HEADER_SIZE, s->footer_buf,
> HEADER_SIZE)
> + != HEADER_SIZE)
>
> + goto fail;
>
Always braces for if.
> + if (strncmp(footer->creator, "conectix", 8))
>
> + goto fail;
>
Dito.
> + disk_type = VHD_FIXED;
>
> + }
>
>
>
> checksum = be32_to_cpu(footer->checksum);
>
> footer->checksum = 0;
>
> @@ -186,6 +196,14 @@ static int vpc_open(BlockDriverState *bs, int flags)
>
> goto fail;
>
> }
>
>
>
> + // The footer is all that is needed for fixed disks.
>
/* ... */
> + if (disk_type == VHD_FIXED) {
>
> + // The fixed disk format doesn't use footer->data_offset but it
>
> + // should be initialized
>
/* ... */
> + footer->data_offset = be64_to_cpu(0xFFFFFFFFFFFFFFFF);
>
For 32-bit hosts 64-bit constants need ULL suffix.
> + return 0;
>
> + }
>
> +
>
> if (bdrv_pread(bs->file, be64_to_cpu(footer->data_offset), buf,
> HEADER_SIZE)
> != HEADER_SIZE)
>
> goto fail;
>
> @@ -533,7 +551,7 @@ static int calculate_geometry(int64_t total_sectors,
> uint16_t* cyls,
> return 0;
>
> }
>
>
>
> -static int vpc_create(const char *filename, QEMUOptionParameter *options)
>
> +static int vpc_create_dynamic_disk(const char *filename, int64_t total_size)
>
> {
>
> uint8_t buf[1024];
>
> struct vhd_footer* footer = (struct vhd_footer*) buf;
>
> @@ -544,13 +562,9 @@ static int vpc_create(const char *filename,
> QEMUOptionParameter *options)
> uint8_t heads = 0;
>
> uint8_t secs_per_cyl = 0;
>
> size_t block_size, num_bat_entries;
>
> - int64_t total_sectors = 0;
>
> + int64_t total_sectors = total_size / BDRV_SECTOR_SIZE;
>
> int ret = -EIO;
>
>
>
> - // Read out options
>
> - total_sectors = get_option_parameter(options, BLOCK_OPT_SIZE)->value.n /
>
> - BDRV_SECTOR_SIZE;
>
> -
>
> // Create the file
>
> fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
>
> if (fd < 0)
>
> @@ -657,6 +671,101 @@ static int vpc_create(const char *filename,
> QEMUOptionParameter *options)
> return ret;
>
> }
>
>
>
> +static int vpc_create_fixed_disk(const char *filename, int64_t total_size)
>
> +{
>
> + uint8_t buf[1024];
>
> + struct vhd_footer* footer = (struct vhd_footer*) buf;
>
> + int fd;
>
> + uint16_t cyls = 0;
>
> + uint8_t heads = 0;
>
> + uint8_t secs_per_cyl = 0;
>
> + int64_t total_sectors = total_size / BDRV_SECTOR_SIZE;
>
> + int ret = -EIO;
>
> +
>
> + // Create the file
>
/* ... */
> + fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
>
> + if (fd < 0)
>
Braces. I'll stop here.
> + return -EIO;
>
> +
>
> + /* Calculate matching total_size and geometry. */
>
> + if (calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl)) {
>
> + ret = -EFBIG;
>
> + goto fail;
>
> + }
>
> + total_sectors = (int64_t) cyls * heads * secs_per_cyl;
>
> +
>
> + // Prepare the Hard Disk Footer
>
> + memset(buf, 0, 1024);
>
> +
>
> + memcpy(footer->creator, "conectix", 8);
>
> + // TODO Check if "qemu" creator_app is ok for VPC
>
> + memcpy(footer->creator_app, "qemu", 4);
>
> + memcpy(footer->creator_os, "Wi2k", 4);
>
> +
>
> + footer->features = be32_to_cpu(0x02);
>
> + footer->version = be32_to_cpu(0x00010000);
>
> + footer->data_offset = be64_to_cpu(0xFFFFFFFFFFFFFFFF);
>
ULL
> + footer->timestamp = be32_to_cpu(time(NULL) - VHD_TIMESTAMP_BASE);
>
> +
>
> + // Version of Virtual PC 2007
>
> + footer->major = be16_to_cpu(0x0005);
>
> + footer->minor =be16_to_cpu(0x0003);
>
Space after = please.
> + footer->orig_size = be64_to_cpu(total_size);
>
> + footer->size = be64_to_cpu(total_size);
>
> + footer->cyls = be16_to_cpu(cyls);
>
> + footer->heads = heads;
>
> + footer->secs_per_cyl = secs_per_cyl;
>
> +
>
> + footer->type = be32_to_cpu(VHD_FIXED);
>
> +
>
> + // TODO uuid is missing
>
Do you know what exactly it means, or did you just copy it?
> +
>
> + footer->checksum = be32_to_cpu(vpc_checksum(buf, HEADER_SIZE));
>
> +
>
> + total_size += 512;
>
> + if (ftruncate(fd, total_size) != 0) {
>
> + ret = -errno;
>
> + goto fail;
>
> + }
>
> + if (lseek(fd, -512, SEEK_END) < 0) {
>
> + goto fail;
>
> + }
>
> + if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE) {
>
> + goto fail;
> + }
> +
> + ret = 0;
> +
> + fail:
> + close(fd);
> + return ret;
> +}
> +
> +static int vpc_create(const char *filename, QEMUOptionParameter *options)
> +{
> + int64_t total_size = 0;
> + QEMUOptionParameter *disk_type_param;
> + int ret = -EIO;
> +
> + // Read out options
> + total_size = get_option_parameter(options, BLOCK_OPT_SIZE)->value.n;
> +
> + disk_type_param = get_option_parameter(options, BLOCK_OPT_TYPE);
> + if (disk_type_param && disk_type_param->value.s) {
> + if (!strcmp(disk_type_param->value.s, "dynamic") ) {
> + ret = vpc_create_dynamic_disk(filename, total_size);
> + }
> + else if (!strcmp(disk_type_param->value.s, "fixed") ) {
else on same line as } please. Also superfluous spaces after "dynamic")
and "fixed").
> + ret = vpc_create_fixed_disk(filename, total_size);
> + }
> + else
> + ret = -EINVAL;
> + } else {
> + ret = vpc_create_dynamic_disk(filename, total_size);
> + }
> + return ret;
> +}
> +
> static void vpc_close(BlockDriverState *bs)
> {
> BDRVVPCState *s = bs->opaque;
> @@ -675,6 +784,13 @@ static QEMUOptionParameter vpc_create_options[] = {
> .type = OPT_SIZE,
> .help = "Virtual disk size"
> },
> + {
> + .name = BLOCK_OPT_TYPE,
> + .type = OPT_STRING,
> + .help =
> + "Type of virtual hard disk format. Supported formats are "
> + "{dynamic (default) | fixed} "
> + },
> { NULL }
> };
>
> diff --git a/block_int.h b/block_int.h
> index 311bd2a..6d6cc96 100644
> --- a/block_int.h
> +++ b/block_int.h
> @@ -50,6 +50,7 @@
> #define BLOCK_OPT_TABLE_SIZE "table_size"
> #define BLOCK_OPT_PREALLOC "preallocation"
> #define BLOCK_OPT_SUBFMT "subformat"
> +#define BLOCK_OPT_TYPE "type"
>
> typedef struct BdrvTrackedRequest BdrvTrackedRequest;
>
Regards,
Andreas
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