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refactor dev-md.c, separating out the magic number detection

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This commit is contained in:
Alasdair Kergon 2007-10-24 00:30:30 +00:00
parent 0f8387c2d6
commit 951e1064c9
1 changed files with 24 additions and 7 deletions
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31
lib/device/dev-md.c
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@ -17,6 +17,8 @@
#include "metadata.h" #include "metadata.h"
#include "xlate.h" #include "xlate.h"
#ifdef linux
/* Lifted from <linux/raid/md_p.h> because of difficulty including it */ /* Lifted from <linux/raid/md_p.h> because of difficulty including it */
#define MD_SB_MAGIC 0xa92b4efc #define MD_SB_MAGIC 0xa92b4efc
@ -25,6 +27,19 @@
#define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) \ #define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) \
- MD_RESERVED_SECTORS) - MD_RESERVED_SECTORS)
static int _dev_has_md_magic(struct device *dev, uint64_t sb_offset)
{
uint32_t md_magic;
/* Version 1 is little endian; version 0.90.0 is machine endian */
if (dev_read(dev, sb_offset, sizeof(uint32_t), &md_magic) &&
((md_magic == xlate32(MD_SB_MAGIC)) ||
(md_magic == MD_SB_MAGIC)))
return 1;
return 0;
}
/* /*
* Returns -1 on error * Returns -1 on error
*/ */
@ -32,8 +47,6 @@ int dev_is_md(struct device *dev, uint64_t *sb)
{ {
int ret = 0; int ret = 0;
#ifdef linux
uint64_t size, sb_offset; uint64_t size, sb_offset;
uint32_t md_magic; uint32_t md_magic;
@ -53,10 +66,7 @@ int dev_is_md(struct device *dev, uint64_t *sb)
sb_offset = MD_NEW_SIZE_SECTORS(size) << SECTOR_SHIFT; sb_offset = MD_NEW_SIZE_SECTORS(size) << SECTOR_SHIFT;
/* Check if it is an md component device. */ /* Check if it is an md component device. */
/* Version 1 is little endian; version 0.90.0 is machine endian */ if (_dev_has_md_magic(dev, sb_offset)) {
if (dev_read(dev, sb_offset, sizeof(uint32_t), &md_magic) &&
((md_magic == xlate32(MD_SB_MAGIC)) ||
(md_magic == MD_SB_MAGIC))) {
if (sb) if (sb)
*sb = sb_offset; *sb = sb_offset;
ret = 1; ret = 1;
@ -65,7 +75,14 @@ int dev_is_md(struct device *dev, uint64_t *sb)
if (!dev_close(dev)) if (!dev_close(dev))
stack; stack;
#endif
return ret; return ret;
} }
#else
int dev_is_md(struct device *dev __attribute((unused)), uint64_t *sb __attribute((unused)))
{
return 0;
}
#endif