[lvm-devel] master - devices: simplify md superblock checking code
David Teigland
teigland at sourceware.org
Thu Jul 9 15:50:13 UTC 2020
Gitweb: https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=00c9a788cc617e5e40746dee2e17287d61ee5c81
Commit: 00c9a788cc617e5e40746dee2e17287d61ee5c81
Parent: 23774f997ea077f2cbe8a32bd8bccdd7f4560cca
Author: David Teigland <teigland at redhat.com>
AuthorDate: Thu Sep 19 12:17:36 2019 -0500
Committer: David Teigland <teigland at redhat.com>
CommitterDate: Thu Jul 9 10:48:34 2020 -0500
devices: simplify md superblock checking code
---
lib/device/dev-md.c | 135 ++++++++++++++++++++++------------------------------
1 file changed, 58 insertions(+), 77 deletions(-)
diff --git a/lib/device/dev-md.c b/lib/device/dev-md.c
index 13a3c168a..23ce41af1 100644
--- a/lib/device/dev-md.c
+++ b/lib/device/dev-md.c
@@ -75,7 +75,7 @@ struct ddf_header {
char padding[472];
};
-static int _dev_has_ddf_magic(struct device *dev, uint64_t devsize_sectors)
+static int _dev_has_ddf_magic(struct device *dev, uint64_t devsize_sectors, uint64_t *sb_offset)
{
struct ddf_header hdr;
uint32_t crc, our_crc;
@@ -99,8 +99,7 @@ static int _dev_has_ddf_magic(struct device *dev, uint64_t devsize_sectors)
if ((cpu_to_be32(our_crc) == crc) ||
(cpu_to_le32(our_crc) == crc)) {
- log_debug_devs("Found md ddf magic at %llu crc %x %s",
- (unsigned long long)off, crc, dev_name(dev));
+ *sb_offset = off;
return 1;
} else {
log_debug_devs("Found md ddf magic at %llu wrong crc %x disk %x %s",
@@ -123,8 +122,7 @@ static int _dev_has_ddf_magic(struct device *dev, uint64_t devsize_sectors)
if ((cpu_to_be32(our_crc) == crc) ||
(cpu_to_le32(our_crc) == crc)) {
- log_debug_devs("Found md ddf magic at %llu crc %x %s",
- (unsigned long long)off, crc, dev_name(dev));
+ *sb_offset = off;
return 1;
} else {
log_debug_devs("Found md ddf magic at %llu wrong crc %x disk %x %s",
@@ -136,46 +134,6 @@ static int _dev_has_ddf_magic(struct device *dev, uint64_t devsize_sectors)
return 0;
}
-/*
- * Calculate the position of the superblock.
- * It is always aligned to a 4K boundary and
- * depending on minor_version, it can be:
- * 0: At least 8K, but less than 12K, from end of device
- * 1: At start of device
- * 2: 4K from start of device.
- */
-typedef enum {
- MD_MINOR_VERSION_MIN,
- MD_MINOR_V0 = MD_MINOR_VERSION_MIN,
- MD_MINOR_V1,
- MD_MINOR_V2,
- MD_MINOR_VERSION_MAX = MD_MINOR_V2
-} md_minor_version_t;
-
-static uint64_t _v1_sb_offset(uint64_t size, md_minor_version_t minor_version)
-{
- uint64_t sb_offset;
-
- switch(minor_version) {
- case MD_MINOR_V0:
- sb_offset = (size - 8 * 2) & ~(4 * 2 - 1ULL);
- break;
- case MD_MINOR_V1:
- sb_offset = 0;
- break;
- case MD_MINOR_V2:
- sb_offset = 4 * 2;
- break;
- default:
- log_warn(INTERNAL_ERROR "WARNING: Unknown minor version %d.",
- minor_version);
- return 0;
- }
- sb_offset <<= SECTOR_SHIFT;
-
- return sb_offset;
-}
-
/*
* _udev_dev_is_md_component() only works if
* external_device_info_source="udev"
@@ -218,7 +176,6 @@ static int _udev_dev_is_md_component(struct device *dev)
*/
static int _native_dev_is_md_component(struct device *dev, uint64_t *offset_found, int full)
{
- md_minor_version_t minor;
uint64_t size, sb_offset;
int ret;
@@ -234,9 +191,9 @@ static int _native_dev_is_md_component(struct device *dev, uint64_t *offset_foun
return 0;
/*
- * Old md versions locate the magic number at the end of the device.
- * Those checks can't be satisfied with the initial bcache data, and
- * would require an extra read i/o at the end of every device. Issuing
+ * Some md versions locate the magic number at the end of the device.
+ * Those checks can't be satisfied with the initial scan data, and
+ * require an extra read i/o at the end of every device. Issuing
* an extra read to every device in every command, just to check for
* the old md format is a bad tradeoff.
*
@@ -247,54 +204,78 @@ static int _native_dev_is_md_component(struct device *dev, uint64_t *offset_foun
* and set it for commands that could possibly write to an md dev
* (pvcreate/vgcreate/vgextend).
*/
- if (!full) {
- sb_offset = 0;
- if (_dev_has_md_magic(dev, sb_offset)) {
- log_debug_devs("Found md magic number at offset 0 of %s.", dev_name(dev));
- ret = 1;
- goto out;
- }
- sb_offset = 8 << SECTOR_SHIFT;
- if (_dev_has_md_magic(dev, sb_offset)) {
- log_debug_devs("Found md magic number at offset %d of %s.", (int)sb_offset, dev_name(dev));
- ret = 1;
- goto out;
- }
+ /*
+ * md superblock version 1.1 at offset 0 from start
+ */
+
+ if (_dev_has_md_magic(dev, 0)) {
+ log_debug_devs("Found md magic number at offset 0 of %s.", dev_name(dev));
+ ret = 1;
+ goto out;
+ }
+
+ /*
+ * md superblock version 1.2 at offset 4KB from start
+ */
+ if (_dev_has_md_magic(dev, 4096)) {
+ log_debug_devs("Found md magic number at offset 4096 of %s.", dev_name(dev));
+ ret = 1;
+ goto out;
+ }
+
+ if (!full) {
ret = 0;
goto out;
}
- /* Version 0.90.0 */
- /* superblock at 64KB from end of device */
+ /*
+ * Handle superblocks at the end of the device.
+ */
+
+ /*
+ * md superblock version 0 at 64KB from end of device
+ * (after end is aligned to 64KB)
+ */
+
sb_offset = MD_NEW_SIZE_SECTORS(size) << SECTOR_SHIFT;
+
if (_dev_has_md_magic(dev, sb_offset)) {
+ log_debug_devs("Found md magic number at offset %llu of %s.", (unsigned long long)sb_offset, dev_name(dev));
ret = 1;
goto out;
}
- minor = MD_MINOR_VERSION_MIN;
+ /*
+ * md superblock version 1.0 at 8KB from end of device
+ */
- /* Version 1, try v1.0 -> v1.2 */
+ sb_offset = ((size - 8 * 2) & ~(4 * 2 - 1ULL)) << SECTOR_SHIFT;
- do {
- /* superblock at start or 4K from start */
- sb_offset = _v1_sb_offset(size, minor);
- if (_dev_has_md_magic(dev, sb_offset)) {
- ret = 1;
- goto out;
- }
- } while (++minor <= MD_MINOR_VERSION_MAX);
+ if (_dev_has_md_magic(dev, sb_offset)) {
+ log_debug_devs("Found md magic number at offset %llu of %s.", (unsigned long long)sb_offset, dev_name(dev));
+ ret = 1;
+ goto out;
+ }
+
+ /*
+ * md imsm superblock 1K from end of device
+ */
- /* superblock 1K from end of device */
if (_dev_has_imsm_magic(dev, size)) {
+ log_debug_devs("Found md imsm magic number at offset %llu of %s.", (unsigned long long)sb_offset, dev_name(dev));
+ sb_offset = 1024;
ret = 1;
goto out;
}
- /* superblock 512 bytes from end, or 128KB from end */
- if (_dev_has_ddf_magic(dev, size)) {
+ /*
+ * md ddf superblock 512 bytes from end, or 128KB from end
+ */
+
+ if (_dev_has_ddf_magic(dev, size, &sb_offset)) {
+ log_debug_devs("Found md ddf magic number at offset %llu of %s.", (unsigned long long)sb_offset, dev_name(dev));
ret = 1;
goto out;
}
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