Btrfs: create a logical->phsyical block number mapping scheme
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e092332..c872a7e 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -10,10 +10,30 @@
#include "transaction.h"
#include "btrfs_inode.h"
+struct dev_lookup {
+ u64 block_start;
+ u64 num_blocks;
+ struct block_device *bdev;
+};
+
+u64 bh_blocknr(struct buffer_head *bh)
+{
+ int blkbits = bh->b_page->mapping->host->i_blkbits;
+ u64 blocknr = bh->b_page->index << (PAGE_CACHE_SHIFT - blkbits);
+ unsigned long offset;
+
+ if (PageHighMem(bh->b_page))
+ offset = (unsigned long)bh->b_data;
+ else
+ offset = bh->b_data - (char *)page_address(bh->b_page);
+ blocknr += offset >> (PAGE_CACHE_SHIFT - blkbits);
+ return blocknr;
+}
+
static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf)
{
struct btrfs_node *node = btrfs_buffer_node(buf);
- if (buf->b_blocknr != btrfs_header_blocknr(&node->header)) {
+ if (bh_blocknr(buf) != btrfs_header_blocknr(&node->header)) {
BUG();
}
return 0;
@@ -40,7 +60,7 @@
head = page_buffers(page);
bh = head;
do {
- if (buffer_mapped(bh) && bh->b_blocknr == blocknr) {
+ if (buffer_mapped(bh) && bh_blocknr(bh) == blocknr) {
ret = bh;
get_bh(bh);
goto out_unlock;
@@ -56,6 +76,33 @@
return ret;
}
+static int map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh,
+ u64 logical)
+{
+ struct dev_lookup *lookup[2];
+ char b[BDEVNAME_SIZE];
+
+ int ret;
+
+ root = root->fs_info->dev_root;
+ ret = radix_tree_gang_lookup(&root->fs_info->dev_radix,
+ (void **)lookup,
+ (unsigned long)logical,
+ ARRAY_SIZE(lookup));
+ if (ret == 0 || lookup[0]->block_start > logical ||
+ lookup[0]->block_start + lookup[0]->num_blocks <= logical) {
+ ret = -ENOENT;
+ goto out;
+ }
+ bh->b_bdev = lookup[0]->bdev;
+ bh->b_blocknr = logical - lookup[0]->block_start;
+printk("logical mapping %Lu to %lu bdev %s\n", logical, bh->b_blocknr, bdevname(bh->b_bdev, b));
+ set_buffer_mapped(bh);
+ ret = 0;
+out:
+ return ret;
+}
+
struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root,
u64 blocknr)
{
@@ -66,6 +113,7 @@
struct buffer_head *bh;
struct buffer_head *head;
struct buffer_head *ret = NULL;
+ int err;
u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits);
page = grab_cache_page(mapping, index);
@@ -78,11 +126,10 @@
bh = head;
do {
if (!buffer_mapped(bh)) {
- bh->b_bdev = root->fs_info->sb->s_bdev;
- bh->b_blocknr = first_block;
- set_buffer_mapped(bh);
+ err = map_bh_to_logical(root, bh, first_block);
+ BUG_ON(err);
}
- if (bh->b_blocknr == blocknr) {
+ if (bh_blocknr(bh) == blocknr) {
ret = bh;
get_bh(bh);
goto out_unlock;
@@ -98,38 +145,13 @@
return ret;
}
-static sector_t max_block(struct block_device *bdev)
-{
- sector_t retval = ~((sector_t)0);
- loff_t sz = i_size_read(bdev->bd_inode);
-
- if (sz) {
- unsigned int size = block_size(bdev);
- unsigned int sizebits = blksize_bits(size);
- retval = (sz >> sizebits);
- }
- return retval;
-}
-
static int btree_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh, int create)
{
- if (iblock >= max_block(inode->i_sb->s_bdev)) {
- if (create)
- return -EIO;
-
- /*
- * for reads, we're just trying to fill a partial page.
- * return a hole, they will have to call get_block again
- * before they can fill it, and they will get -EIO at that
- * time
- */
- return 0;
- }
- bh->b_bdev = inode->i_sb->s_bdev;
- bh->b_blocknr = iblock;
- set_buffer_mapped(bh);
- return 0;
+ int err;
+ struct btrfs_root *root = BTRFS_I(bh->b_page->mapping->host)->root;
+ err = map_bh_to_logical(root, bh, iblock);
+ return err;
}
int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
@@ -164,8 +186,8 @@
return ret;
if (verify) {
if (memcmp(bh->b_data, result, BTRFS_CSUM_SIZE)) {
- printk("checksum verify failed on %lu\n",
- bh->b_blocknr);
+ printk("checksum verify failed on %Lu\n",
+ bh_blocknr(bh));
return 1;
}
} else {
@@ -386,10 +408,12 @@
GFP_NOFS);
int ret;
struct btrfs_super_block *disk_super;
+ struct dev_lookup *dev_lookup;
init_bit_radix(&fs_info->pinned_radix);
init_bit_radix(&fs_info->pending_del_radix);
INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
+ INIT_RADIX_TREE(&fs_info->dev_radix, GFP_NOFS);
sb_set_blocksize(sb, 4096);
fs_info->running_transaction = NULL;
fs_info->tree_root = tree_root;
@@ -422,6 +446,13 @@
__setup_root(sb->s_blocksize, tree_root,
fs_info, BTRFS_ROOT_TREE_OBJECTID);
+
+ dev_lookup = kmalloc(sizeof(*dev_lookup), GFP_NOFS);
+ dev_lookup->block_start = 0;
+ dev_lookup->num_blocks = (u32)-2;
+ dev_lookup->bdev = sb->s_bdev;
+ ret = radix_tree_insert(&fs_info->dev_radix, (u32)-2, dev_lookup);
+ BUG_ON(ret);
fs_info->sb_buffer = read_tree_block(tree_root,
BTRFS_SUPER_INFO_OFFSET /
sb->s_blocksize);
@@ -432,6 +463,14 @@
if (!btrfs_super_root(disk_super))
return NULL;
+ radix_tree_delete(&fs_info->dev_radix, (u32)-2);
+ dev_lookup->block_start = btrfs_super_device_block_start(disk_super);
+ dev_lookup->num_blocks = btrfs_super_device_num_blocks(disk_super);
+ ret = radix_tree_insert(&fs_info->dev_radix,
+ dev_lookup->block_start +
+ dev_lookup->num_blocks, dev_lookup);
+ BUG_ON(ret);
+
fs_info->disk_super = disk_super;
dev_root->node = read_tree_block(tree_root,
btrfs_super_device_root(disk_super));
@@ -459,7 +498,7 @@
struct buffer_head *bh = root->fs_info->sb_buffer;
btrfs_set_super_root(root->fs_info->disk_super,
- root->fs_info->tree_root->node->b_blocknr);
+ bh_blocknr(root->fs_info->tree_root->node));
lock_buffer(bh);
WARN_ON(atomic_read(&bh->b_count) < 1);
clear_buffer_dirty(bh);
@@ -506,6 +545,29 @@
}
return 0;
}
+static int free_dev_radix(struct btrfs_fs_info *fs_info)
+{
+ struct dev_lookup *lookup[8];
+ struct block_device *super_bdev = fs_info->sb->s_bdev;
+ int ret;
+ int i;
+ while(1) {
+ ret = radix_tree_gang_lookup(&fs_info->dev_radix,
+ (void **)lookup, 0,
+ ARRAY_SIZE(lookup));
+ if (!ret)
+ break;
+ for (i = 0; i < ret; i++) {
+ if (lookup[i]->bdev != super_bdev)
+ close_bdev_excl(lookup[i]->bdev);
+ radix_tree_delete(&fs_info->dev_radix,
+ lookup[i]->block_start +
+ lookup[i]->num_blocks);
+ kfree(lookup[i]);
+ }
+ }
+ return 0;
+}
int close_ctree(struct btrfs_root *root)
{
@@ -537,6 +599,8 @@
crypto_free_hash(fs_info->hash_tfm);
truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
iput(fs_info->btree_inode);
+
+ free_dev_radix(fs_info);
del_fs_roots(fs_info);
kfree(fs_info->extent_root);
kfree(fs_info->tree_root);