Btrfs: leave btree locks spinning more often

[linux-2.6-block.git] / fs / btrfs / disk-io.c

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 1f1d89b188189ab5db429ba88457412b2d6503f6..9244cd7313d451f69ebac1df57fb6a16aff548af 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -668,14 +668,31 @@ static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 {
        struct extent_io_tree *tree;
+       struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
+       struct extent_buffer *eb;
+       int was_dirty;
+
        tree = &BTRFS_I(page->mapping->host)->io_tree;
+       if (!(current->flags & PF_MEMALLOC)) {
+               return extent_write_full_page(tree, page,
+                                             btree_get_extent, wbc);
+       }
 
-       if (current->flags & PF_MEMALLOC) {
-               redirty_page_for_writepage(wbc, page);
-               unlock_page(page);
-               return 0;
+       redirty_page_for_writepage(wbc, page);
+       eb = btrfs_find_tree_block(root, page_offset(page),
+                                     PAGE_CACHE_SIZE);
+       WARN_ON(!eb);
+
+       was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
+       if (!was_dirty) {
+               spin_lock(&root->fs_info->delalloc_lock);
+               root->fs_info->dirty_metadata_bytes += PAGE_CACHE_SIZE;
+               spin_unlock(&root->fs_info->delalloc_lock);
        }
-       return extent_write_full_page(tree, page, btree_get_extent, wbc);
+       free_extent_buffer(eb);
+
+       unlock_page(page);
+       return 0;
 }
 
 static int btree_writepages(struct address_space *mapping,
@@ -684,15 +701,15 @@ static int btree_writepages(struct address_space *mapping,
        struct extent_io_tree *tree;
        tree = &BTRFS_I(mapping->host)->io_tree;
        if (wbc->sync_mode == WB_SYNC_NONE) {
+               struct btrfs_root *root = BTRFS_I(mapping->host)->root;
                u64 num_dirty;
-               u64 start = 0;
                unsigned long thresh = 32 * 1024 * 1024;
 
                if (wbc->for_kupdate)
                        return 0;
 
-               num_dirty = count_range_bits(tree, &start, (u64)-1,
-                                            thresh, EXTENT_DIRTY);
+               /* this is a bit racy, but that's ok */
+               num_dirty = root->fs_info->dirty_metadata_bytes;
                if (num_dirty < thresh)
                        return 0;
        }
@@ -859,9 +876,17 @@ int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
            root->fs_info->running_transaction->transid) {
                btrfs_assert_tree_locked(buf);
 
-               /* ugh, clear_extent_buffer_dirty can be expensive */
-               btrfs_set_lock_blocking(buf);
+               if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
+                       spin_lock(&root->fs_info->delalloc_lock);
+                       if (root->fs_info->dirty_metadata_bytes >= buf->len)
+                               root->fs_info->dirty_metadata_bytes -= buf->len;
+                       else
+                               WARN_ON(1);
+                       spin_unlock(&root->fs_info->delalloc_lock);
+               }
 
+               /* ugh, clear_extent_buffer_dirty needs to lock the page */
+               btrfs_set_lock_blocking(buf);
                clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
                                          buf);
        }
@@ -2348,8 +2373,7 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
        struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
        u64 transid = btrfs_header_generation(buf);
        struct inode *btree_inode = root->fs_info->btree_inode;
-
-       btrfs_set_lock_blocking(buf);
+       int was_dirty;
 
        btrfs_assert_tree_locked(buf);
        if (transid != root->fs_info->generation) {
@@ -2360,7 +2384,13 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
                        (unsigned long long)root->fs_info->generation);
                WARN_ON(1);
        }
-       set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree, buf);
+       was_dirty = set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
+                                           buf);
+       if (!was_dirty) {
+               spin_lock(&root->fs_info->delalloc_lock);
+               root->fs_info->dirty_metadata_bytes += buf->len;
+               spin_unlock(&root->fs_info->delalloc_lock);
+       }
 }
 
 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
@@ -2400,6 +2430,7 @@ int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
 int btree_lock_page_hook(struct page *page)
 {
        struct inode *inode = page->mapping->host;
+       struct btrfs_root *root = BTRFS_I(inode)->root;
        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
        struct extent_buffer *eb;
        unsigned long len;
@@ -2415,6 +2446,16 @@ int btree_lock_page_hook(struct page *page)
 
        btrfs_tree_lock(eb);
        btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
+
+       if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
+               spin_lock(&root->fs_info->delalloc_lock);
+               if (root->fs_info->dirty_metadata_bytes >= eb->len)
+                       root->fs_info->dirty_metadata_bytes -= eb->len;
+               else
+                       WARN_ON(1);
+               spin_unlock(&root->fs_info->delalloc_lock);
+       }
+
        btrfs_tree_unlock(eb);
        free_extent_buffer(eb);
 out: