Btrfs: Limit btree writeback to prevent seeks

[deliverable/linux.git] / fs / btrfs / disk-io.c

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 5a7e60d7f443044cb457ec637dadabdad96c36e9..28e9ef8a3253db0e8443d26cb0c752577b380625 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -43,6 +43,8 @@ static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
 }
 #endif
 
+static struct extent_map_ops btree_extent_map_ops;
+
 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
                                            u64 bytenr, u32 blocksize)
 {
@@ -159,7 +161,7 @@ static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 {
        struct extent_map_tree *tree;
-       u64 start = page->index << PAGE_CACHE_SHIFT;
+       u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
        u64 found_start;
        int found_level;
        unsigned long len;
@@ -188,15 +190,38 @@ out:
        return 0;
 }
 
-static int btree_writepage(struct page *page, struct writeback_control *wbc)
+static int btree_writepage_io_hook(struct page *page, u64 start, u64 end)
 {
-       struct extent_map_tree *tree;
        struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
-       tree = &BTRFS_I(page->mapping->host)->extent_tree;
 
        csum_dirty_buffer(root, page);
+       return 0;
+}
+
+static int btree_writepage(struct page *page, struct writeback_control *wbc)
+{
+       struct extent_map_tree *tree;
+       tree = &BTRFS_I(page->mapping->host)->extent_tree;
        return extent_write_full_page(tree, page, btree_get_extent, wbc);
 }
+
+static int btree_writepages(struct address_space *mapping,
+                           struct writeback_control *wbc)
+{
+       struct extent_map_tree *tree;
+       tree = &BTRFS_I(mapping->host)->extent_tree;
+       if (wbc->sync_mode == WB_SYNC_NONE) {
+               u64 num_dirty;
+               u64 start = 0;
+               unsigned long thresh = 96 * 1024 * 1024;
+               num_dirty = count_range_bits(tree, &start, thresh, EXTENT_DIRTY);
+               if (num_dirty < thresh) {
+                       return 0;
+               }
+       }
+       return extent_writepages(tree, mapping, btree_get_extent, wbc);
+}
+
 int btree_readpage(struct file *file, struct page *page)
 {
        struct extent_map_tree *tree;
@@ -251,6 +276,7 @@ static int btree_writepage(struct page *page, struct writeback_control *wbc)
 static struct address_space_operations btree_aops = {
        .readpage       = btree_readpage,
        .writepage      = btree_writepage,
+       .writepages     = btree_writepages,
        .releasepage    = btree_releasepage,
        .invalidatepage = btree_invalidatepage,
        .sync_page      = block_sync_page,
@@ -538,6 +564,8 @@ struct btrfs_root *open_ctree(struct super_block *sb)
        extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
                             fs_info->btree_inode->i_mapping,
                             GFP_NOFS);
+       BTRFS_I(fs_info->btree_inode)->extent_tree.ops = &btree_extent_map_ops;
+
        extent_map_tree_init(&fs_info->free_space_cache,
                             fs_info->btree_inode->i_mapping, GFP_NOFS);
        extent_map_tree_init(&fs_info->block_group_cache,
@@ -550,6 +578,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
                             fs_info->btree_inode->i_mapping, GFP_NOFS);
        fs_info->do_barriers = 1;
        fs_info->closing = 0;
+       fs_info->total_pinned = 0;
 
        INIT_DELAYED_WORK(&fs_info->trans_work, btrfs_transaction_cleaner);
        BTRFS_I(fs_info->btree_inode)->root = tree_root;
@@ -832,3 +861,7 @@ int btrfs_read_buffer(struct extent_buffer *buf)
        return read_extent_buffer_pages(&BTRFS_I(btree_inode)->extent_tree,
                                        buf, 0, 1);
 }
+
+static struct extent_map_ops btree_extent_map_ops = {
+       .writepage_io_hook = btree_writepage_io_hook,
+};