Btrfs: New data=ordered implementation

The old data=ordered code would force commit to wait until all the data extents from the transaction were fully on disk. This introduced large latencies into the commit and stalled new writers in the transaction for a long time. The new code changes the way data allocations and extents work: * When delayed allocation is filled, data extents are reserved, and the extent bit EXTENT_ORDERED is set on the entire range of the extent. A struct btrfs_ordered_extent is allocated an inserted into a per-inode rbtree to track the pending extents. * As each page is written EXTENT_ORDERED is cleared on the bytes corresponding to that page. * When all of the bytes corresponding to a single struct btrfs_ordered_extent are written, The previously reserved extent is inserted into the FS btree and into the extent allocation trees. The checksums for the file data are also updated. Signed-off-by: Chris Mason <chris.mason@oracle.com>
mariux64 · Sep 25, 2008 · e6dcd2d · e6dcd2d
1 parent 77a41af
commit e6dcd2d
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Showing 14 changed files with 910 additions and 502 deletions.
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
@@ -21,6 +21,7 @@
 
 #include "extent_map.h"
 #include "extent_io.h"
+#include "ordered-data.h"
 
 /* in memory btrfs inode */
 struct btrfs_inode {
@@ -32,9 +33,8 @@ struct btrfs_inode {
 	struct extent_io_tree io_failure_tree;
 	struct mutex csum_mutex;
 	struct inode vfs_inode;
-	atomic_t ordered_writeback;
+	struct btrfs_ordered_inode_tree ordered_tree;
 
-	u64 ordered_trans;
 	/*
 	 * transid of the trans_handle that last modified this inode
 	 */

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
@@ -25,6 +25,7 @@
 #include <linux/fs.h>
 #include <linux/completion.h>
 #include <linux/backing-dev.h>
+#include <linux/wait.h>
 #include <asm/kmap_types.h>
 #include "bit-radix.h"
 #include "extent_io.h"
@@ -37,6 +38,7 @@ extern struct kmem_cache *btrfs_trans_handle_cachep;
 extern struct kmem_cache *btrfs_transaction_cachep;
 extern struct kmem_cache *btrfs_bit_radix_cachep;
 extern struct kmem_cache *btrfs_path_cachep;
+struct btrfs_ordered_sum;
 
 #define BTRFS_MAGIC "_B5RfS_M"
 
@@ -510,6 +512,7 @@ struct btrfs_fs_info {
 	u64 max_inline;
 	u64 alloc_start;
 	struct btrfs_transaction *running_transaction;
+	wait_queue_head_t transaction_throttle;
 	struct btrfs_super_block super_copy;
 	struct btrfs_super_block super_for_commit;
 	struct block_device *__bdev;
@@ -541,6 +544,7 @@ struct btrfs_fs_info {
 	 */
 	struct btrfs_workers workers;
 	struct btrfs_workers endio_workers;
+	struct btrfs_workers endio_write_workers;
 	struct btrfs_workers submit_workers;
 	struct task_struct *transaction_kthread;
 	struct task_struct *cleaner_kthread;
@@ -1384,6 +1388,17 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
 		       u64 owner, u64 owner_offset,
 		       u64 empty_size, u64 hint_byte,
 		       u64 search_end, struct btrfs_key *ins, u64 data);
+int btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
+				struct btrfs_root *root,
+				u64 root_objectid, u64 ref_generation,
+				u64 owner, u64 owner_offset,
+				struct btrfs_key *ins);
+int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
+				  struct btrfs_root *root,
+				  u64 num_bytes, u64 min_alloc_size,
+				  u64 empty_size, u64 hint_byte,
+				  u64 search_end, struct btrfs_key *ins,
+				  u64 data);
 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 		  struct extent_buffer *buf);
 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
@@ -1556,9 +1571,9 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
 			     u64 bytenr, int mod);
 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
 			   struct btrfs_root *root, struct inode *inode,
-			   struct bio *bio, char *sums);
+			   struct btrfs_ordered_sum *sums);
 int btrfs_csum_one_bio(struct btrfs_root *root,
-		       struct bio *bio, char **sums_ret);
+		       struct bio *bio, struct btrfs_ordered_sum **sums_ret);
 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
 					  struct btrfs_root *root,
 					  struct btrfs_path *path,

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
@@ -407,7 +407,11 @@ static int end_workqueue_bio(struct bio *bio,
 	end_io_wq->error = err;
 	end_io_wq->work.func = end_workqueue_fn;
 	end_io_wq->work.flags = 0;
-	btrfs_queue_worker(&fs_info->endio_workers, &end_io_wq->work);
+	if (bio->bi_rw & (1 << BIO_RW))
+		btrfs_queue_worker(&fs_info->endio_write_workers,
+				   &end_io_wq->work);
+	else
+		btrfs_queue_worker(&fs_info->endio_workers, &end_io_wq->work);
 
 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
 	return 0;
@@ -1286,6 +1290,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	mutex_init(&fs_info->transaction_kthread_mutex);
 	mutex_init(&fs_info->cleaner_mutex);
 	mutex_init(&fs_info->volume_mutex);
+	init_waitqueue_head(&fs_info->transaction_throttle);
 
 #if 0
 	ret = add_hasher(fs_info, "crc32c");
@@ -1325,9 +1330,13 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	btrfs_init_workers(&fs_info->workers, fs_info->thread_pool_size);
 	btrfs_init_workers(&fs_info->submit_workers, fs_info->thread_pool_size);
 	btrfs_init_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
+	btrfs_init_workers(&fs_info->endio_write_workers,
+			   fs_info->thread_pool_size);
 	btrfs_start_workers(&fs_info->workers, 1);
 	btrfs_start_workers(&fs_info->submit_workers, 1);
 	btrfs_start_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
+	btrfs_start_workers(&fs_info->endio_write_workers,
+			    fs_info->thread_pool_size);
 
 	err = -EINVAL;
 	if (btrfs_super_num_devices(disk_super) > fs_devices->open_devices) {
@@ -1447,6 +1456,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 	extent_io_tree_empty_lru(&BTRFS_I(fs_info->btree_inode)->io_tree);
 	btrfs_stop_workers(&fs_info->workers);
 	btrfs_stop_workers(&fs_info->endio_workers);
+	btrfs_stop_workers(&fs_info->endio_write_workers);
 	btrfs_stop_workers(&fs_info->submit_workers);
 fail_iput:
 	iput(fs_info->btree_inode);
@@ -1702,6 +1712,7 @@ int close_ctree(struct btrfs_root *root)
 
 	btrfs_stop_workers(&fs_info->workers);
 	btrfs_stop_workers(&fs_info->endio_workers);
+	btrfs_stop_workers(&fs_info->endio_write_workers);
 	btrfs_stop_workers(&fs_info->submit_workers);
 
 	iput(fs_info->btree_inode);

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
@@ -1895,36 +1895,17 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
-/*
- * finds a free extent and does all the dirty work required for allocation
- * returns the key for the extent through ins, and a tree buffer for
- * the first block of the extent through buf.
- *
- * returns 0 if everything worked, non-zero otherwise.
- */
-int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
-		       struct btrfs_root *root,
-		       u64 num_bytes, u64 min_alloc_size,
-		       u64 root_objectid, u64 ref_generation,
-		       u64 owner, u64 owner_offset,
-		       u64 empty_size, u64 hint_byte,
-		       u64 search_end, struct btrfs_key *ins, u64 data)
+static int __btrfs_reserve_extent(struct btrfs_trans_handle *trans,
+				  struct btrfs_root *root,
+				  u64 num_bytes, u64 min_alloc_size,
+				  u64 empty_size, u64 hint_byte,
+				  u64 search_end, struct btrfs_key *ins,
+				  u64 data)
 {
 	int ret;
-	int pending_ret;
-	u64 super_used;
-	u64 root_used;
 	u64 search_start = 0;
 	u64 alloc_profile;
-	u32 sizes[2];
 	struct btrfs_fs_info *info = root->fs_info;
-	struct btrfs_root *extent_root = info->extent_root;
-	struct btrfs_extent_item *extent_item;
-	struct btrfs_extent_ref *ref;
-	struct btrfs_path *path;
-	struct btrfs_key keys[2];
-
-	maybe_lock_mutex(root);
 
 	if (data) {
 		alloc_profile = info->avail_data_alloc_bits &
@@ -1974,11 +1955,48 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
 	}
 	if (ret) {
 		printk("allocation failed flags %Lu\n", data);
-	}
-	if (ret) {
 		BUG();
-		goto out;
 	}
+	clear_extent_dirty(&root->fs_info->free_space_cache,
+			   ins->objectid, ins->objectid + ins->offset - 1,
+			   GFP_NOFS);
+	return 0;
+}
+
+int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
+				  struct btrfs_root *root,
+				  u64 num_bytes, u64 min_alloc_size,
+				  u64 empty_size, u64 hint_byte,
+				  u64 search_end, struct btrfs_key *ins,
+				  u64 data)
+{
+	int ret;
+	maybe_lock_mutex(root);
+	ret = __btrfs_reserve_extent(trans, root, num_bytes, min_alloc_size,
+				     empty_size, hint_byte, search_end, ins,
+				     data);
+	maybe_unlock_mutex(root);
+	return ret;
+}
+
+static int __btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
+					 struct btrfs_root *root,
+					 u64 root_objectid, u64 ref_generation,
+					 u64 owner, u64 owner_offset,
+					 struct btrfs_key *ins)
+{
+	int ret;
+	int pending_ret;
+	u64 super_used;
+	u64 root_used;
+	u64 num_bytes = ins->offset;
+	u32 sizes[2];
+	struct btrfs_fs_info *info = root->fs_info;
+	struct btrfs_root *extent_root = info->extent_root;
+	struct btrfs_extent_item *extent_item;
+	struct btrfs_extent_ref *ref;
+	struct btrfs_path *path;
+	struct btrfs_key keys[2];
 
 	/* block accounting for super block */
 	spin_lock_irq(&info->delalloc_lock);
@@ -1990,21 +2008,13 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
 	root_used = btrfs_root_used(&root->root_item);
 	btrfs_set_root_used(&root->root_item, root_used + num_bytes);
 
-	clear_extent_dirty(&root->fs_info->free_space_cache,
-			   ins->objectid, ins->objectid + ins->offset - 1,
-			   GFP_NOFS);
-
 	if (root == extent_root) {
 		set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
 				ins->objectid + ins->offset - 1,
 				EXTENT_LOCKED, GFP_NOFS);
 		goto update_block;
 	}
 
-	WARN_ON(trans->alloc_exclude_nr);
-	trans->alloc_exclude_start = ins->objectid;
-	trans->alloc_exclude_nr = ins->offset;
-
 	memcpy(&keys[0], ins, sizeof(*ins));
 	keys[1].offset = hash_extent_ref(root_objectid, ref_generation,
 					 owner, owner_offset);
@@ -2054,6 +2064,51 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
 		BUG();
 	}
 out:
+	return ret;
+}
+
+int btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
+				struct btrfs_root *root,
+				u64 root_objectid, u64 ref_generation,
+				u64 owner, u64 owner_offset,
+				struct btrfs_key *ins)
+{
+	int ret;
+	maybe_lock_mutex(root);
+	ret = __btrfs_alloc_reserved_extent(trans, root, root_objectid,
+					    ref_generation, owner,
+					    owner_offset, ins);
+	maybe_unlock_mutex(root);
+	return ret;
+}
+/*
+ * finds a free extent and does all the dirty work required for allocation
+ * returns the key for the extent through ins, and a tree buffer for
+ * the first block of the extent through buf.
+ *
+ * returns 0 if everything worked, non-zero otherwise.
+ */
+int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
+		       struct btrfs_root *root,
+		       u64 num_bytes, u64 min_alloc_size,
+		       u64 root_objectid, u64 ref_generation,
+		       u64 owner, u64 owner_offset,
+		       u64 empty_size, u64 hint_byte,
+		       u64 search_end, struct btrfs_key *ins, u64 data)
+{
+	int ret;
+
+	maybe_lock_mutex(root);
+
+	ret = __btrfs_reserve_extent(trans, root, num_bytes,
+				     min_alloc_size, empty_size, hint_byte,
+				     search_end, ins, data);
+	BUG_ON(ret);
+	ret = __btrfs_alloc_reserved_extent(trans, root, root_objectid,
+					    ref_generation, owner,
+					    owner_offset, ins);
+	BUG_ON(ret);
+
 	maybe_unlock_mutex(root);
 	return ret;
 }
@@ -2288,8 +2343,8 @@ static int noinline walk_down_tree(struct btrfs_trans_handle *trans,
 			mutex_lock(&root->fs_info->alloc_mutex);
 
 			/* we've dropped the lock, double check */
-			ret = drop_snap_lookup_refcount(root, bytenr,
-						blocksize, &refs);
+			ret = lookup_extent_ref(NULL, root, bytenr, blocksize,
+						&refs);
 			BUG_ON(ret);
 			if (refs != 1) {
 				parent = path->nodes[*level];
@@ -2584,7 +2639,6 @@ static int noinline relocate_inode_pages(struct inode *inode, u64 start,
 	kfree(ra);
 	trans = btrfs_start_transaction(BTRFS_I(inode)->root, 1);
 	if (trans) {
-		btrfs_add_ordered_inode(inode);
 		btrfs_end_transaction(trans, BTRFS_I(inode)->root);
 		mark_inode_dirty(inode);
 	}