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>

1 files changed, 13 insertions, 1 deletions

diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index f1960dafaa19..2268a7995896 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -13,6 +13,8 @@
 #define EXTENT_DEFRAG (1 << 6)
 #define EXTENT_DEFRAG_DONE (1 << 7)
 #define EXTENT_BUFFER_FILLED (1 << 8)
+#define EXTENT_ORDERED (1 << 9)
+#define EXTENT_ORDERED_METADATA (1 << 10)
 #define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)
 
 /*
@@ -42,7 +44,7 @@ struct extent_io_ops {
         int (*readpage_end_io_hook)(struct page *page, u64 start, u64 end,
                                     struct extent_state *state);
         int (*writepage_end_io_hook)(struct page *page, u64 start, u64 end,
-                                      struct extent_state *state);
+                                      struct extent_state *state, int uptodate);
         int (*set_bit_hook)(struct inode *inode, u64 start, u64 end,
                             unsigned long old, unsigned long bits);
         int (*clear_bit_hook)(struct inode *inode, u64 start, u64 end,
@@ -131,6 +133,8 @@ int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
                    int bits, int filled);
 int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
                       int bits, gfp_t mask);
+int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
+                     int bits, int wake, int delete, gfp_t mask);
 int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
                     int bits, gfp_t mask);
 int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
@@ -141,8 +145,14 @@ int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
                      gfp_t mask);
 int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
                        gfp_t mask);
+int clear_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
+                       gfp_t mask);
+int clear_extent_ordered_metadata(struct extent_io_tree *tree, u64 start,
+                                  u64 end, gfp_t mask);
 int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
                      gfp_t mask);
+int set_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
+                     gfp_t mask);
 int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
                           u64 *start_ret, u64 *end_ret, int bits);
 struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,
@@ -209,6 +219,8 @@ void memset_extent_buffer(struct extent_buffer *eb, char c,
                           unsigned long start, unsigned long len);
 int wait_on_extent_buffer_writeback(struct extent_io_tree *tree,
                                     struct extent_buffer *eb);
+int wait_on_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end);
+int wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int bits);
 int clear_extent_buffer_dirty(struct extent_io_tree *tree,
                               struct extent_buffer *eb);
 int set_extent_buffer_dirty(struct extent_io_tree *tree,