Btrfs: Split the extent_map code into two parts

There is now extent_map for mapping offsets in the file to disk and
extent_io for state tracking, IO submission and extent_bufers.

The new extent_map code shifts from [start,end] pairs to [start,len], and
pushes the locking out into the caller.  This allows a few performance
optimizations and is easier to use.

A number of extent_map usage bugs were fixed, mostly with failing
to remove extent_map entries when changing the file.

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

1 files changed, 21 insertions, 22 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index b69a46691a96..1cf125ab7822 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -63,7 +63,7 @@ static int cache_block_group(struct btrfs_root *root,
         int ret;
         struct btrfs_key key;
         struct extent_buffer *leaf;
-        struct extent_map_tree *free_space_cache;
+        struct extent_io_tree *free_space_cache;
         int slot;
         u64 last = 0;
         u64 hole_size;
@@ -158,7 +158,7 @@ struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
                                                          btrfs_fs_info *info,
                                                          u64 bytenr)
 {
-        struct extent_map_tree *block_group_cache;
+        struct extent_io_tree *block_group_cache;
         struct btrfs_block_group_cache *block_group = NULL;
         u64 ptr;
         u64 start;
@@ -281,7 +281,7 @@ struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
                                                  int data, int owner)
 {
         struct btrfs_block_group_cache *cache;
-        struct extent_map_tree *block_group_cache;
+        struct extent_io_tree *block_group_cache;
         struct btrfs_block_group_cache *found_group = NULL;
         struct btrfs_fs_info *info = root->fs_info;
         u64 used;
@@ -951,7 +951,7 @@ fail:
 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
                                    struct btrfs_root *root)
 {
-        struct extent_map_tree *block_group_cache;
+        struct extent_io_tree *block_group_cache;
         struct btrfs_block_group_cache *cache;
         int ret;
         int err = 0;
@@ -1107,12 +1107,12 @@ static int update_pinned_extents(struct btrfs_root *root,
         return 0;
 }
 
-int btrfs_copy_pinned(struct btrfs_root *root, struct extent_map_tree *copy)
+int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
 {
         u64 last = 0;
         u64 start;
         u64 end;
-        struct extent_map_tree *pinned_extents = &root->fs_info->pinned_extents;
+        struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
         int ret;
 
         while(1) {
@@ -1128,12 +1128,12 @@ int btrfs_copy_pinned(struct btrfs_root *root, struct extent_map_tree *copy)
 
 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
                                struct btrfs_root *root,
-                               struct extent_map_tree *unpin)
+                               struct extent_io_tree *unpin)
 {
         u64 start;
         u64 end;
         int ret;
-        struct extent_map_tree *free_space_cache;
+        struct extent_io_tree *free_space_cache;
         free_space_cache = &root->fs_info->free_space_cache;
 
         while(1) {
@@ -1329,8 +1329,8 @@ static int del_pending_extents(struct btrfs_trans_handle *trans, struct
         int err = 0;
         u64 start;
         u64 end;
-        struct extent_map_tree *pending_del;
-        struct extent_map_tree *pinned_extents;
+        struct extent_io_tree *pending_del;
+        struct extent_io_tree *pinned_extents;
 
         pending_del = &extent_root->fs_info->pending_del;
         pinned_extents = &extent_root->fs_info->pinned_extents;
@@ -1802,7 +1802,7 @@ struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
 
         set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
                          buf->start + buf->len - 1, GFP_NOFS);
-        set_extent_bits(&BTRFS_I(root->fs_info->btree_inode)->extent_tree,
+        set_extent_bits(&BTRFS_I(root->fs_info->btree_inode)->io_tree,
                         buf->start, buf->start + buf->len - 1,
                         EXTENT_CSUM, GFP_NOFS);
         buf->flags |= EXTENT_CSUM;
@@ -2166,7 +2166,7 @@ static int noinline relocate_inode_pages(struct inode *inode, u64 start,
         unsigned long i;
         struct page *page;
         struct btrfs_root *root = BTRFS_I(inode)->root;
-        struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
         struct file_ra_state *ra;
 
         ra = kzalloc(sizeof(*ra), GFP_NOFS);
@@ -2195,15 +2195,14 @@ static int noinline relocate_inode_pages(struct inode *inode, u64 start,
                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
                 page_end = page_start + PAGE_CACHE_SIZE - 1;
 
-                lock_extent(em_tree, page_start, page_end, GFP_NOFS);
+                lock_extent(io_tree, page_start, page_end, GFP_NOFS);
 
                 delalloc_start = page_start;
-                existing_delalloc =
-                        count_range_bits(&BTRFS_I(inode)->extent_tree,
-                                         &delalloc_start, page_end,
-                                         PAGE_CACHE_SIZE, EXTENT_DELALLOC);
+                existing_delalloc = count_range_bits(io_tree,
+                                             &delalloc_start, page_end,
+                                             PAGE_CACHE_SIZE, EXTENT_DELALLOC);
 
-                set_extent_delalloc(em_tree, page_start,
+                set_extent_delalloc(io_tree, page_start,
                                     page_end, GFP_NOFS);
 
                 spin_lock(&root->fs_info->delalloc_lock);
@@ -2211,7 +2210,7 @@ static int noinline relocate_inode_pages(struct inode *inode, u64 start,
                                                  existing_delalloc;
                 spin_unlock(&root->fs_info->delalloc_lock);
 
-                unlock_extent(em_tree, page_start, page_end, GFP_NOFS);
+                unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
                 set_page_dirty(page);
                 unlock_page(page);
                 page_cache_release(page);
@@ -2379,7 +2378,7 @@ int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size)
         u64 cur_byte;
         u64 total_found;
         struct btrfs_fs_info *info = root->fs_info;
-        struct extent_map_tree *block_group_cache;
+        struct extent_io_tree *block_group_cache;
         struct btrfs_key key;
         struct btrfs_key found_key;
         struct extent_buffer *leaf;
@@ -2561,7 +2560,7 @@ int btrfs_grow_extent_tree(struct btrfs_trans_handle *trans,
         struct btrfs_block_group_cache *cache;
         struct btrfs_block_group_item *item;
         struct btrfs_fs_info *info = root->fs_info;
-        struct extent_map_tree *block_group_cache;
+        struct extent_io_tree *block_group_cache;
         struct btrfs_key key;
         struct extent_buffer *leaf;
         int ret;
@@ -2645,7 +2644,7 @@ int btrfs_read_block_groups(struct btrfs_root *root)
         int bit;
         struct btrfs_block_group_cache *cache;
         struct btrfs_fs_info *info = root->fs_info;
-        struct extent_map_tree *block_group_cache;
+        struct extent_io_tree *block_group_cache;
         struct btrfs_key key;
         struct btrfs_key found_key;
         struct extent_buffer *leaf;