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MDRAID: refactored to use parse() and setup(), rendamed "inherit" to …
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…"parent"

Signed-off-by: Tomas Mudrunka <[email protected]>
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@Harvie
Harvie committed Dec 31, 2024
1 parent 1bca566 commit d3202a2
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13 changes: 7 additions & 6 deletions README.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -487,15 +487,16 @@ Generates MD RAID images.

Options:

:label: Text name of array, eg: localhost:42
:label: Text name of array (optional) eg: localhost:42
:level: RAID level, currently only level 1 (default) is supported
:devices: Number of devices in array (default 1)
:role: 0 based index of this image in whole array. (autoassigned by default)
:timestamp: Unix timestamp of array creation (current time by default)
:timestamp: Unix timestamp of array creation (current time by default, has to match across array devices)
:raid-uuid: UUID of whole array (has to be identical across all disks in array, random by default)
:disk-uuid: UUID of disk (has to be unique for each array member disk, random by default)
:image: Image of data to be preloaded into array (optional)
:inherit: Image to inherit array identity/config from (when creating extra members of existing array)
:parent: Image to inherit array identity/config from (when creating extra members of existing array).
Effectively overrides all array-wide options mentioned here and replaces them with values from parent.

For example here only the first image has configuration and the UUID/timestamp is generated on demand::

Expand All @@ -507,15 +508,15 @@ For example here only the first image has configuration and the UUID/timestamp i
}
}

Then to create second member to that array we just inherit config from the first member::
Then to create second member to that array we just inherit config from the parent member::

image mdraid-b.img {
mdraid {
inherit = "mdraid-a.img"
parent = "mdraid-a.img"
}
}

Role number is 0 for the master image and when other images inherit configuration from it, they are assigned roles from autoincrementing counter.
Default role number is 0 for the parent image and when other images inherit configuration from it, they are assigned roles from autoincrementing counter.


qemu
Expand Down
145 changes: 78 additions & 67 deletions image-mdraid.c
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Original file line number Diff line number Diff line change
Expand Up @@ -50,10 +50,10 @@ static time_t mdraid_time = 0; //Array creation timestamp has to be identical ac
/*
* bitmap structures:
* Taken from Linux kernel drivers/md/md-bitmap.h
* (Currently it's missing from linux-libc-dev debian package, so cannot be included)
* (Currently it's missing from linux-libc-dev debian package, so cannot be simply included)
*/

#define BITMAP_MAGIC 0x6d746962
#define BITMAP_MAGIC 0x6d746962 /* This is actualy just char string saying "bitm" :-) */

/* use these for bitmap->flags and bitmap->sb->state bit-fields */
enum bitmap_state {
Expand Down Expand Up @@ -95,11 +95,15 @@ typedef struct bitmap_super_s {
* devices. For raid10 it is the size of the array.
*/


//This structure is used to store mdraid state data in handler_priv
typedef struct mdraid_img_s {
struct image *img_data;
struct image *img_inherit;
struct mdp_superblock_1 *sb;
bitmap_super_t bsb;
struct partition img_data_part; //Partition of data to be imported to raid
struct partition img_parent_part; //Partition of parent raid image (we can inherit config from it)
struct image *img_data; //Images for aforementioned partitions
struct image *img_parent; //Dtto
struct mdp_superblock_1 *sb; //Actual mdraid superblock that is gonna be stored on disk
bitmap_super_t bsb; //Actual bitmap superblock that is gonna be stored on disk
__le16 last_role; //This is counter used by slave devices to take roles
} mdraid_img_t;

Expand All @@ -120,6 +124,7 @@ static unsigned int calc_sb_1_csum(struct mdp_superblock_1 * sb)
}
*/

//Temporarily set checksum in struct to 0 while remembering original value
disk_csum = sb->sb_csum;
sb->sb_csum = 0;
newcsum = 0;
Expand All @@ -132,26 +137,28 @@ static unsigned int calc_sb_1_csum(struct mdp_superblock_1 * sb)
newcsum += __le16_to_cpu(*(unsigned short*) isuper);

csum = (newcsum & 0xffffffff) + (newcsum >> 32);
sb->sb_csum = disk_csum;
sb->sb_csum = disk_csum; //Set checksum in struct back to original value
return __cpu_to_le32(csum);
}

static int mdraid_generate(struct image *image) {
mdraid_img_t *md = image->handler_priv;
mdraid_img_t *mdi = NULL; //Inheriting from this if not NULL
mdraid_img_t *mdp = NULL; //Inheriting from this parent if not NULL
__le16 max_devices;

if (md->img_inherit) {
mdi = md->img_inherit->handler_priv;
max_devices = mdi->sb->raid_disks;
//Determine max_devices while considering possibility of inheritance from other image
if (md->img_parent) {
mdp = md->img_parent->handler_priv;
max_devices = mdp->sb->raid_disks;
} else {
max_devices = cfg_getint(image->imagesec, "devices");
}

//Determine role of this device in array
__le16 role = cfg_getint(image->imagesec, "role");
if (cfg_getint(image->imagesec, "role") == -1) { //If role is -1 it should be autoassigned to inheriting devices
if (mdi) {
role = ++mdi->last_role; //Take role from master and increment its counter
if (cfg_getint(image->imagesec, "role") == -1) { //If role is -1 it should be autoassigned to parenting devices
if (mdp) {
role = ++mdp->last_role; //Take role from master and increment its counter
} else {
role = 0; //Master has role of 0
}
Expand All @@ -173,14 +180,17 @@ static int mdraid_generate(struct image *image) {
struct mdp_superblock_1 *sb = md->sb = xzalloc(superblock_size);
bitmap_super_t *bsb = &md->bsb;

if (mdi) {
memcpy(md->sb, mdi->sb, superblock_size);
//memcpy(&md->bsb, &mdi->bsb, sizeof(bitmap_super_t));
if (mdp) {
//We are inheriting the superblock in this case
memcpy(md->sb, mdp->sb, superblock_size);
//memcpy(&md->bsb, &mdp->bsb, sizeof(bitmap_super_t));
} else {
//We are not inheriting superblock, therefore we need to fully initialize the array

char *name = cfg_getstr(image->imagesec, "label");

/* constant array information - 128 bytes */
sb->magic = MD_SB_MAGIC; /* MD_SB_MAGIC: 0xa92b4efc - little endian. This is actualy just char string saying "bitm" :-) */
sb->magic = MD_SB_MAGIC; /* MD_SB_MAGIC: 0xa92b4efc - little endian. */
sb->major_version = 1; /* 1 */
sb->feature_map = MD_FEATURE_BITMAP_OFFSET; /* bit 0 set if 'bitmap_offset' is meaningful */
sb->pad0 = 0; /* always set to 0 when writing */
Expand Down Expand Up @@ -229,10 +239,10 @@ static int mdraid_generate(struct image *image) {
//#define WriteMostly1 1 /* mask for writemostly flag in above */
//#define FailFast1 2 /* Should avoid retries and fixups and just fail */

/* Bad block log. If there are any bad blocks the feature flag is set.
* If offset and size are non-zero, that space is reserved and available
*/
sb->bblog_shift = 9; /* shift from sectors to block size */ //TODO: not sure why this is 9
/* Bad block log. If there are any bad blocks the feature flag is set.
* If offset and size are non-zero, that space is reserved and available
*/
sb->bblog_shift = 9; /* shift from sectors to badblock size, typicaly 9-12 (shift by 9 is equal to 512 sectors per badblock) */
sb->bblog_size = 8; /* number of sectors reserved for list */
sb->bblog_offset = sb->bitmap_offset+BITMAP_SECTORS_MAX+8; /* sector offset from superblock to bblog, signed - not unsigned */

Expand All @@ -259,7 +269,7 @@ static int mdraid_generate(struct image *image) {
sb->sb_csum = calc_sb_1_csum(sb);

//Prepare bitmap superblock (bitmaps don't have checksums for performance reasons)
bsb->magic = BITMAP_MAGIC; /* 0 BITMAP_MAGIC */
bsb->magic = BITMAP_MAGIC; /* 0 BITMAP_MAGIC - This is actualy just char string saying "bitm" :-) */
bsb->version = 4; /* v4 is compatible with mdraid v1.2, 4 the bitmap major for now, could change... */
memcpy(bsb->uuid, sb->set_uuid, sizeof(bsb->uuid)); /* 8 128 bit uuid - must match md device uuid */
//bsb->events = 0; /* 24 event counter for the bitmap (1)*/
Expand Down Expand Up @@ -301,7 +311,7 @@ static int mdraid_generate(struct image *image) {
return 0;
}

static int mdraid_setup(struct image *image, cfg_t *cfg) {
static int mdraid_parse(struct image *image, cfg_t *cfg) {
mdraid_img_t *md = xzalloc(sizeof(mdraid_img_t));
image->handler_priv = md;

Expand All @@ -316,55 +326,55 @@ static int mdraid_setup(struct image *image, cfg_t *cfg) {
return 1;
}

//Inherit config from master
char *inherit = cfg_getstr(image->imagesec, "inherit");
if (inherit) {
//Add inherit image as dependency (so it's built first)
struct partition *part;
part = xzalloc(sizeof *part);
part->image = inherit;
list_add_tail(&part->list, &image->partitions);

md->img_inherit = image_get(part->image);
//Inherit config from parent
md->img_parent_part.image = cfg_getstr(image->imagesec, "parent");
if (md->img_parent_part.image) {
//Add parent partition as dependency (so it's built first)
list_add_tail(&md->img_parent_part.list, &image->partitions);

if (md->img_inherit) {
image_info(image, "MDRAID will inherit array metadata config from: %s\n", part->image);
} else {
image_error(image, "MDRAID cannot find image config to inherit metadata from: %s\n", part->image);
//Find parent image
md->img_parent = image_get(md->img_parent_part.image);
if (!md->img_parent) {
image_error(image, "MDRAID cannot find parent image to inherit metadata config from: %s\n", md->img_parent_part.image);
return 9;
}

image->size = md->img_inherit->size;
//Inherit image size from parent
image_info(image, "MDRAID will inherit array metadata config from parent: %s\n", md->img_parent->file);
image->size = md->img_parent->size;
}

//Find data image to be put inside the array
md->img_data = NULL;
char *img_data_path;
if (md->img_inherit) {
img_data_path = cfg_getstr(md->img_inherit->imagesec, "image");
//Find data partition to be put inside the array
if (md->img_parent) {
md->img_data_part.image = cfg_getstr(md->img_parent->imagesec, "image");
} else {
img_data_path = cfg_getstr(image->imagesec, "image");
md->img_data_part.image = cfg_getstr(image->imagesec, "image");
}

//Add data partition as dependency (so it's built first)
if (md->img_data_part.image) {
list_add_tail(&md->img_data_part.list, &image->partitions);
}
if (img_data_path) {
//Add data image as dependency (so it's built first)
struct partition *part;
part = xzalloc(sizeof *part);
part->image = img_data_path;
list_add_tail(&part->list, &image->partitions);

if (part->image) {
image_info(image, "MDRAID using data from: %s\n", part->image);
md->img_data = image_get(part->image); //TODO: will this work for pre-existing images not generated by genimage???
if (!md->img_data) {
image_error(image, "MDRAID cannot get image definition: %s\n", part->image);
return 8;
}
if (image->size == 0)
image->size = roundup(md->img_data->size + DATA_OFFSET_BYTES, MDRAID_ALIGN_BYTES);
if (image->size < (md->img_data->size + DATA_OFFSET_BYTES)) {
image_error(image, "MDRAID image too small to fit %s\n", part->image);
return 3;
}

return 0;
}

static int mdraid_setup(struct image *image, cfg_t *cfg) {
mdraid_img_t *md = image->handler_priv;

//Find data image and its metadata if data partition exists
if (md->img_data_part.image) {
image_info(image, "MDRAID using data from: %s\n", md->img_data_part.image);
md->img_data = image_get(md->img_data_part.image);
if (!md->img_data) {
image_error(image, "MDRAID cannot get image definition: %s\n", md->img_data_part.image);
return 8;
}
if (image->size == 0)
image->size = roundup(md->img_data->size + DATA_OFFSET_BYTES, MDRAID_ALIGN_BYTES);
if (image->size < (md->img_data->size + DATA_OFFSET_BYTES)) {
image_error(image, "MDRAID image too small to fit %s\n", md->img_data->file);
return 3;
}
} else {
image_info(image, "MDRAID is created without data.\n");
Expand All @@ -388,14 +398,15 @@ static cfg_opt_t mdraid_opts[] = {
CFG_STR("raid-uuid", NULL, CFGF_NONE),
CFG_STR("disk-uuid", NULL, CFGF_NONE),
CFG_STR("image", NULL, CFGF_NONE),
CFG_STR("inherit", NULL, CFGF_NONE),
CFG_STR("parent", NULL, CFGF_NONE),
CFG_END()
};

struct image_handler mdraid_handler = {
.type = "mdraid",
.no_rootpath = cfg_true,
.generate = mdraid_generate,
.parse = mdraid_parse,
.setup = mdraid_setup,
.generate = mdraid_generate,
.opts = mdraid_opts,
};
2 changes: 1 addition & 1 deletion test/mdraid.config
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,6 @@ image test.mdraid-a {

image test.mdraid-b {
mdraid {
inherit = "test.mdraid-a"
parent = "test.mdraid-a"
}
}

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