Btrfs: Implement raid0 when multiple devices are present
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 263f01c..d8fce32 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -18,6 +18,7 @@
#include <linux/sched.h>
#include <linux/bio.h>
#include <linux/buffer_head.h>
+#include <asm/div64.h>
#include "ctree.h"
#include "extent_map.h"
#include "disk-io.h"
@@ -25,10 +26,24 @@
#include "print-tree.h"
#include "volumes.h"
-struct map_lookup {
+struct stripe {
struct btrfs_device *dev;
u64 physical;
};
+
+struct map_lookup {
+ u64 type;
+ int io_align;
+ int io_width;
+ int stripe_len;
+ int sector_size;
+ int num_stripes;
+ struct stripe stripes[];
+};
+
+#define map_lookup_size(n) (sizeof(struct map_lookup) + \
+ (sizeof(struct stripe) * (n)))
+
static DEFINE_MUTEX(uuid_mutex);
static LIST_HEAD(fs_uuids);
@@ -592,6 +607,7 @@
u64 *num_bytes, u64 type)
{
u64 dev_offset;
+ struct btrfs_fs_info *info = extent_root->fs_info;
struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
struct btrfs_stripe *stripes;
struct btrfs_device *device = NULL;
@@ -610,10 +626,18 @@
int looped = 0;
int ret;
int index;
+ int stripe_len = 64 * 1024;
struct btrfs_key key;
if (list_empty(dev_list))
return -ENOSPC;
+
+ if (type & BTRFS_BLOCK_GROUP_RAID0)
+ num_stripes = btrfs_super_num_devices(&info->super_copy);
+ if (type & BTRFS_BLOCK_GROUP_DATA)
+ stripe_len = 64 * 1024;
+ if (type & (BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_SYSTEM))
+ stripe_len = 32 * 1024;
again:
INIT_LIST_HEAD(&private_devs);
cur = dev_list->next;
@@ -650,9 +674,15 @@
if (!chunk)
return -ENOMEM;
+ map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
+ if (!map) {
+ kfree(chunk);
+ return -ENOMEM;
+ }
+
stripes = &chunk->stripe;
- *num_bytes = calc_size;
+ *num_bytes = calc_size * num_stripes;
index = 0;
while(index < num_stripes) {
BUG_ON(list_empty(&private_devs));
@@ -669,6 +699,8 @@
ret = btrfs_update_device(trans, device);
BUG_ON(ret);
+ map->stripes[index].dev = device;
+ map->stripes[index].physical = dev_offset;
btrfs_set_stack_stripe_devid(stripes + index, device->devid);
btrfs_set_stack_stripe_offset(stripes + index, dev_offset);
physical = dev_offset;
@@ -680,12 +712,18 @@
key.offset = *num_bytes;
key.type = BTRFS_CHUNK_ITEM_KEY;
btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
- btrfs_set_stack_chunk_stripe_len(chunk, 64 * 1024);
+ btrfs_set_stack_chunk_stripe_len(chunk, stripe_len);
btrfs_set_stack_chunk_type(chunk, type);
btrfs_set_stack_chunk_num_stripes(chunk, num_stripes);
- btrfs_set_stack_chunk_io_align(chunk, extent_root->sectorsize);
- btrfs_set_stack_chunk_io_width(chunk, extent_root->sectorsize);
+ btrfs_set_stack_chunk_io_align(chunk, stripe_len);
+ btrfs_set_stack_chunk_io_width(chunk, stripe_len);
btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
+ map->sector_size = extent_root->sectorsize;
+ map->stripe_len = stripe_len;
+ map->io_align = stripe_len;
+ map->io_width = stripe_len;
+ map->type = type;
+ map->num_stripes = num_stripes;
ret = btrfs_insert_item(trans, chunk_root, &key, chunk,
btrfs_chunk_item_size(num_stripes));
@@ -695,25 +733,11 @@
em = alloc_extent_map(GFP_NOFS);
if (!em)
return -ENOMEM;
- map = kmalloc(sizeof(*map), GFP_NOFS);
- if (!map) {
- free_extent_map(em);
- return -ENOMEM;
- }
-
em->bdev = (struct block_device *)map;
em->start = key.objectid;
em->len = key.offset;
em->block_start = 0;
- map->physical = physical;
- map->dev = device;
-
- if (!map->dev) {
- kfree(map);
- free_extent_map(em);
- return -EIO;
- }
kfree(chunk);
em_tree = &extent_root->fs_info->mapping_tree.map_tree;
@@ -758,6 +782,9 @@
struct map_lookup *map;
struct extent_map_tree *em_tree = &map_tree->map_tree;
u64 offset;
+ u64 stripe_offset;
+ u64 stripe_nr;
+ int stripe_index;
spin_lock(&em_tree->lock);
@@ -767,9 +794,40 @@
BUG_ON(em->start > logical || em->start + em->len < logical);
map = (struct map_lookup *)em->bdev;
offset = logical - em->start;
- *phys = map->physical + offset;
- *length = em->len - offset;
- *dev = map->dev;
+
+ stripe_nr = offset;
+ /*
+ * stripe_nr counts the total number of stripes we have to stride
+ * to get to this block
+ */
+ do_div(stripe_nr, map->stripe_len);
+
+ stripe_offset = stripe_nr * map->stripe_len;
+ BUG_ON(offset < stripe_offset);
+
+ /* stripe_offset is the offset of this block in its stripe*/
+ stripe_offset = offset - stripe_offset;
+
+ /*
+ * after this do_div call, stripe_nr is the number of stripes
+ * on this device we have to walk to find the data, and
+ * stripe_index is the number of our device in the stripe array
+ */
+ stripe_index = do_div(stripe_nr, map->num_stripes);
+
+ BUG_ON(stripe_index >= map->num_stripes);
+
+ *phys = map->stripes[stripe_index].physical + stripe_offset +
+ stripe_nr * map->stripe_len;
+
+ if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
+ /* we limit the length of each bio to what fits in a stripe */
+ *length = min_t(u64, em->len - offset,
+ map->stripe_len - stripe_offset);
+ } else {
+ *length = em->len - offset;
+ }
+ *dev = map->stripes[stripe_index].dev;
free_extent_map(em);
spin_unlock(&em_tree->lock);
return 0;
@@ -822,7 +880,9 @@
u64 logical;
u64 length;
u64 devid;
+ int num_stripes;
int ret;
+ int i;
logical = key->objectid;
length = key->offset;
@@ -846,7 +906,8 @@
em = alloc_extent_map(GFP_NOFS);
if (!em)
return -ENOMEM;
- map = kmalloc(sizeof(*map), GFP_NOFS);
+ num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
+ map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
if (!map) {
free_extent_map(em);
return -ENOMEM;
@@ -857,13 +918,22 @@
em->len = length;
em->block_start = 0;
- map->physical = btrfs_stripe_offset_nr(leaf, chunk, 0);
- devid = btrfs_stripe_devid_nr(leaf, chunk, 0);
- map->dev = btrfs_find_device(root, devid);
- if (!map->dev) {
- kfree(map);
- free_extent_map(em);
- return -EIO;
+ map->num_stripes = num_stripes;
+ map->io_width = btrfs_chunk_io_width(leaf, chunk);
+ map->io_align = btrfs_chunk_io_align(leaf, chunk);
+ map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
+ map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
+ map->type = btrfs_chunk_type(leaf, chunk);
+ for (i = 0; i < num_stripes; i++) {
+ map->stripes[i].physical =
+ btrfs_stripe_offset_nr(leaf, chunk, i);
+ devid = btrfs_stripe_devid_nr(leaf, chunk, i);
+ map->stripes[i].dev = btrfs_find_device(root, devid);
+ if (!map->stripes[i].dev) {
+ kfree(map);
+ free_extent_map(em);
+ return -EIO;
+ }
}
spin_lock(&map_tree->map_tree.lock);