diff options
Diffstat (limited to 'fs/btrfs/disk-io.c')
-rw-r--r-- | fs/btrfs/disk-io.c | 174 |
1 files changed, 161 insertions, 13 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 758a62aba06..970103f2cac 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1,14 +1,17 @@ #include <linux/module.h> #include <linux/fs.h> +#include <linux/blkdev.h> #include "ctree.h" #include "disk-io.h" #include "transaction.h" + 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 (buf->b_blocknr != btrfs_header_blocknr(&node->header)) { BUG(); + } if (root->node && btrfs_header_parentid(&node->header) != btrfs_header_parentid(btrfs_buffer_header(root->node))) { BUG(); @@ -16,25 +19,154 @@ static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf) return 0; } -struct buffer_head *alloc_tree_block(struct btrfs_root *root, u64 blocknr) +struct buffer_head *btrfs_find_tree_block(struct btrfs_root *root, u64 blocknr) +{ + struct address_space *mapping = root->fs_info->btree_inode->i_mapping; + int blockbits = root->fs_info->sb->s_blocksize_bits; + unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits); + struct page *page; + struct buffer_head *bh; + struct buffer_head *head; + struct buffer_head *ret = NULL; + + page = find_lock_page(mapping, index); + if (!page) + return NULL; + + if (!page_has_buffers(page)) + goto out_unlock; + + head = page_buffers(page); + bh = head; + do { + if (buffer_mapped(bh) && bh->b_blocknr == blocknr) { + ret = bh; + get_bh(bh); + goto out_unlock; + } + bh = bh->b_this_page; + } while (bh != head); +out_unlock: + unlock_page(page); + page_cache_release(page); + return ret; +} + +struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root, + u64 blocknr) +{ + struct address_space *mapping = root->fs_info->btree_inode->i_mapping; + int blockbits = root->fs_info->sb->s_blocksize_bits; + unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits); + struct page *page; + struct buffer_head *bh; + struct buffer_head *head; + struct buffer_head *ret = NULL; + u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits); + page = grab_cache_page(mapping, index); + if (!page) + return NULL; + + wait_on_page_writeback(page); + if (!page_has_buffers(page)) + create_empty_buffers(page, root->fs_info->sb->s_blocksize, 0); + head = page_buffers(page); + 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); + } + if (bh->b_blocknr == blocknr) { + ret = bh; + get_bh(bh); + goto out_unlock; + } + bh = bh->b_this_page; + first_block++; + } while (bh != head); +out_unlock: + unlock_page(page); + page_cache_release(page); + 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; +} + +static int btree_writepage(struct page *page, struct writeback_control *wbc) { - return sb_getblk(root->fs_info->sb, blocknr); + return block_write_full_page(page, btree_get_block, wbc); } -struct buffer_head *find_tree_block(struct btrfs_root *root, u64 blocknr) +static int btree_readpage(struct file * file, struct page * page) { - return sb_getblk(root->fs_info->sb, blocknr); + return block_read_full_page(page, btree_get_block); } +static struct address_space_operations btree_aops = { + .readpage = btree_readpage, + .writepage = btree_writepage, + .sync_page = block_sync_page, +}; + struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr) { - struct buffer_head *buf = sb_bread(root->fs_info->sb, blocknr); + struct buffer_head *bh = NULL; - if (!buf) - return buf; - if (check_tree_block(root, buf)) + bh = btrfs_find_create_tree_block(root, blocknr); + if (!bh) + return bh; + lock_buffer(bh); + if (!buffer_uptodate(bh)) { + get_bh(bh); + bh->b_end_io = end_buffer_read_sync; + submit_bh(READ, bh); + wait_on_buffer(bh); + if (!buffer_uptodate(bh)) + goto fail; + } else { + unlock_buffer(bh); + } + if (check_tree_block(root, bh)) BUG(); - return buf; + return bh; +fail: + brelse(bh); + return NULL; + } int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, @@ -101,11 +233,11 @@ struct btrfs_root *open_ctree(struct super_block *sb, GFP_NOFS); int ret; - /* FIXME: don't be stupid */ if (!btrfs_super_root(disk_super)) return NULL; init_bit_radix(&fs_info->pinned_radix); init_bit_radix(&fs_info->pending_del_radix); + sb_set_blocksize(sb, sb_buffer->b_size); fs_info->running_transaction = NULL; fs_info->fs_root = root; fs_info->tree_root = tree_root; @@ -114,14 +246,30 @@ struct btrfs_root *open_ctree(struct super_block *sb, fs_info->last_inode_alloc = 0; fs_info->last_inode_alloc_dirid = 0; fs_info->disk_super = disk_super; - fs_info->sb_buffer = sb_buffer; fs_info->sb = sb; + fs_info->btree_inode = new_inode(sb); + fs_info->btree_inode->i_ino = 1; + fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size; + fs_info->btree_inode->i_mapping->a_ops = &btree_aops; + mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS); + mutex_init(&fs_info->trans_mutex); mutex_init(&fs_info->fs_mutex); memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert)); memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert)); __setup_root(disk_super, tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID); + + fs_info->sb_buffer = read_tree_block(tree_root, sb_buffer->b_blocknr); + + if (!fs_info->sb_buffer) + return NULL; + + brelse(sb_buffer); + sb_buffer = NULL; + disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data; + fs_info->disk_super = disk_super; + tree_root->node = read_tree_block(tree_root, btrfs_super_root(disk_super)); BUG_ON(!tree_root->node); @@ -137,7 +285,6 @@ struct btrfs_root *open_ctree(struct super_block *sb, ret = find_and_setup_root(disk_super, tree_root, fs_info, BTRFS_FS_TREE_OBJECTID, root); BUG_ON(ret); - root->commit_root = root->node; get_bh(root->node); root->ref_cows = 1; @@ -191,6 +338,7 @@ int close_ctree(struct btrfs_root *root) root->fs_info->tree_root->node); btrfs_block_release(root, root->commit_root); btrfs_block_release(root, root->fs_info->sb_buffer); + iput(root->fs_info->btree_inode); kfree(root->fs_info->extent_root); kfree(root->fs_info->inode_root); kfree(root->fs_info->tree_root); |