Btrfs: Make an unplug function that doesn't unplug every spindle
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 4fc92cf..4602407 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 <linux/blkdev.h>
#include <asm/div64.h>
#include "ctree.h"
#include "extent_map.h"
@@ -930,9 +931,10 @@
return ret;
}
-int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
- u64 logical, u64 *length,
- struct btrfs_multi_bio **multi_ret, int mirror_num)
+static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
+ u64 logical, u64 *length,
+ struct btrfs_multi_bio **multi_ret,
+ int mirror_num, struct page *unplug_page)
{
struct extent_map *em;
struct map_lookup *map;
@@ -944,6 +946,7 @@
int stripes_required = 1;
int stripe_index;
int i;
+ int num_stripes;
struct btrfs_multi_bio *multi = NULL;
if (multi_ret && !(rw & (1 << BIO_RW))) {
@@ -960,10 +963,14 @@
spin_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, logical, *length);
spin_unlock(&em_tree->lock);
+
+ if (!em && unplug_page)
+ return 0;
+
if (!em) {
printk("unable to find logical %Lu\n", logical);
+ BUG();
}
- BUG_ON(!em);
BUG_ON(em->start > logical || em->start + em->len < logical);
map = (struct map_lookup *)em->bdev;
@@ -1010,14 +1017,15 @@
} else {
*length = em->len - offset;
}
- if (!multi_ret)
+
+ if (!multi_ret && !unplug_page)
goto out;
- multi->num_stripes = 1;
+ num_stripes = 1;
stripe_index = 0;
if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
- if (rw & (1 << BIO_RW))
- multi->num_stripes = map->num_stripes;
+ if (unplug_page || (rw & (1 << BIO_RW)))
+ num_stripes = map->num_stripes;
else if (mirror_num) {
stripe_index = mirror_num - 1;
} else {
@@ -1037,7 +1045,7 @@
}
} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
if (rw & (1 << BIO_RW))
- multi->num_stripes = map->num_stripes;
+ num_stripes = map->num_stripes;
else if (mirror_num)
stripe_index = mirror_num - 1;
} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
@@ -1047,8 +1055,8 @@
stripe_index = do_div(stripe_nr, factor);
stripe_index *= map->sub_stripes;
- if (rw & (1 << BIO_RW))
- multi->num_stripes = map->sub_stripes;
+ if (unplug_page || (rw & (1 << BIO_RW)))
+ num_stripes = map->sub_stripes;
else if (mirror_num)
stripe_index += mirror_num - 1;
else
@@ -1063,19 +1071,50 @@
}
BUG_ON(stripe_index >= map->num_stripes);
- for (i = 0; i < multi->num_stripes; i++) {
- multi->stripes[i].physical =
- map->stripes[stripe_index].physical + stripe_offset +
- stripe_nr * map->stripe_len;
- multi->stripes[i].dev = map->stripes[stripe_index].dev;
+ for (i = 0; i < num_stripes; i++) {
+ if (unplug_page) {
+ struct btrfs_device *device;
+ struct backing_dev_info *bdi;
+
+ device = map->stripes[stripe_index].dev;
+ bdi = blk_get_backing_dev_info(device->bdev);
+ if (bdi->unplug_io_fn) {
+ bdi->unplug_io_fn(bdi, unplug_page);
+ }
+ } else {
+ multi->stripes[i].physical =
+ map->stripes[stripe_index].physical +
+ stripe_offset + stripe_nr * map->stripe_len;
+ multi->stripes[i].dev = map->stripes[stripe_index].dev;
+ }
stripe_index++;
}
- *multi_ret = multi;
+ if (multi_ret) {
+ *multi_ret = multi;
+ multi->num_stripes = num_stripes;
+ }
out:
free_extent_map(em);
return 0;
}
+int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
+ u64 logical, u64 *length,
+ struct btrfs_multi_bio **multi_ret, int mirror_num)
+{
+ return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
+ mirror_num, NULL);
+}
+
+int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
+ u64 logical, struct page *page)
+{
+ u64 length = PAGE_CACHE_SIZE;
+ return __btrfs_map_block(map_tree, READ, logical, &length,
+ NULL, 0, page);
+}
+
+
#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
static void end_bio_multi_stripe(struct bio *bio, int err)
#else
@@ -1122,16 +1161,12 @@
u64 logical = bio->bi_sector << 9;
u64 length = 0;
u64 map_length;
- struct bio_vec *bvec;
struct btrfs_multi_bio *multi = NULL;
- int i;
int ret;
int dev_nr = 0;
int total_devs = 1;
- bio_for_each_segment(bvec, bio, i) {
- length += bvec->bv_len;
- }
+ length = bio->bi_size;
map_tree = &root->fs_info->mapping_tree;
map_length = length;