Btrfs: use a btree inode instead of sb_getblk

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 1897f3a65b4fd5846c0bd55212bc1a5069e48eea..b2ebed756c13ddd77ff2f73df4c975820356ca4e 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -233,6 +233,7 @@ struct btrfs_fs_info {
        struct btrfs_super_block *disk_super;
        struct buffer_head *sb_buffer;
        struct super_block *sb;
+       struct inode *btree_inode;
        struct mutex trans_mutex;
        struct mutex fs_mutex;
 };

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 758a62aba063d3f00102e88c8f674140b6ac5b66..970103f2cacd90d17fe02b6dcd7bc115db3beb2f 100644 (file)
--- 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);

diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 099f7eea0ec791cc3967765cda9857e1fd9050f5..c2c38bda704d88129e1a3d6d6d4753d7cb36e9cc 100644 (file)
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -21,7 +21,8 @@ static inline struct btrfs_header *btrfs_buffer_header(struct buffer_head *bh)
 }
 
 struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr);
-struct buffer_head *find_tree_block(struct btrfs_root *root, u64 blocknr);
+struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root,
+                                                u64 blocknr);
 int write_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                     struct buffer_head *buf);
 int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
@@ -37,5 +38,5 @@ int close_ctree(struct btrfs_root *root);
 void btrfs_block_release(struct btrfs_root *root, struct buffer_head *buf);
 int write_ctree_super(struct btrfs_trans_handle *trans,
                      struct btrfs_root *root);
-int mkfs(int fd, u64 num_blocks, u32 blocksize);
+struct buffer_head *btrfs_find_tree_block(struct btrfs_root *root, u64 blocknr);
 #endif

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 176c6dc534ba8adcbe9cdab5e8e96dd2e67cb990..b2ae8e768b6c4f90a7fc2ae1408c770ec4e65507 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -172,8 +172,8 @@ static int pin_down_block(struct btrfs_root *root, u64 blocknr, int pending)
        struct buffer_head *bh;
 
        if (!pending) {
-               bh = sb_find_get_block(root->fs_info->sb, blocknr);
-               if (bh) {
+               bh = btrfs_find_tree_block(root, blocknr);
+               if (bh && buffer_uptodate(bh)) {
                        header = btrfs_buffer_header(bh);
                        if (btrfs_header_generation(header) ==
                            root->fs_info->running_transaction->transid) {
@@ -291,12 +291,10 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                      *root, u64 blocknr, u64 num_blocks, int pin)
 {
        struct btrfs_root *extent_root = root->fs_info->extent_root;
-       struct buffer_head *t;
        int pending_ret;
        int ret;
 
        if (root == extent_root) {
-               t = find_tree_block(root, blocknr);
                pin_down_block(root, blocknr, 1);
                return 0;
        }
@@ -482,7 +480,7 @@ struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
                BUG();
                return NULL;
        }
-       buf = find_tree_block(root, ins.objectid);
+       buf = btrfs_find_create_tree_block(root, ins.objectid);
        set_buffer_uptodate(buf);
        return buf;
 }

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 67659b6ce96283f87efbd78d7c2aca9ea87fbcf6..8f07f462236a40d80f642ca77217ef812f01da32 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -474,6 +474,8 @@ static int btrfs_fill_super(struct super_block * sb, void * data, int silent)
        disk_super = (struct btrfs_super_block *)bh->b_data;
        root = open_ctree(sb, bh, disk_super);
        sb->s_fs_info = root;
+       disk_super = root->fs_info->disk_super;
+
        if (!root) {
                printk("btrfs: open_ctree failed\n");
                return -EIO;
@@ -734,15 +736,15 @@ static int btrfs_sync_fs(struct super_block *sb, int wait)
        struct btrfs_trans_handle *trans;
        struct btrfs_root *root;
        int ret;
+       root = btrfs_sb(sb);
 
        sb->s_dirt = 0;
        if (!wait) {
-               filemap_flush(sb->s_bdev->bd_inode->i_mapping);
+               filemap_flush(root->fs_info->btree_inode->i_mapping);
                return 0;
        }
-       filemap_write_and_wait(sb->s_bdev->bd_inode->i_mapping);
+       filemap_write_and_wait(root->fs_info->btree_inode->i_mapping);
 
-       root = btrfs_sb(sb);
        mutex_lock(&root->fs_info->fs_mutex);
        trans = btrfs_start_transaction(root, 1);
        ret = btrfs_commit_transaction(trans, root);

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 46a596e345f0fd01bb5124dd2c3d42749f5c99dd..b20fb53a0d273c54b0c5f50cb82388421d7f9865 100644 (file)
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -74,7 +74,7 @@ int btrfs_end_transaction(struct btrfs_trans_handle *trans,
 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
                                     struct btrfs_root *root)
 {
-       filemap_write_and_wait(root->fs_info->sb->s_bdev->bd_inode->i_mapping);
+       filemap_write_and_wait(root->fs_info->btree_inode->i_mapping);
        return 0;
 }