Btrfs: extent_map optimizations to cut down on CPU usage
[deliverable/linux.git] / fs / btrfs / file.c
index 844d8807e44a6aee49c9b9b1ec5d31dfb6875b96..fe28404ae7f4c4ca68ec516a19bb3008b7e346e3 100644 (file)
@@ -82,8 +82,9 @@ static void btrfs_drop_pages(struct page **pages, size_t num_pages)
 
 static int insert_inline_extent(struct btrfs_trans_handle *trans,
                                struct btrfs_root *root, struct inode *inode,
-                               u64 offset, ssize_t size,
-                               struct page *page, size_t page_offset)
+                               u64 offset, size_t size,
+                               struct page **pages, size_t page_offset,
+                               int num_pages)
 {
        struct btrfs_key key;
        struct btrfs_path *path;
@@ -91,9 +92,12 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
        char *kaddr;
        unsigned long ptr;
        struct btrfs_file_extent_item *ei;
+       struct page *page;
        u32 datasize;
        int err = 0;
        int ret;
+       int i;
+       ssize_t cur_size;
 
        path = btrfs_alloc_path();
        if (!path)
@@ -104,25 +108,97 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
        key.objectid = inode->i_ino;
        key.offset = offset;
        btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
-       BUG_ON(size >= PAGE_CACHE_SIZE);
-       datasize = btrfs_file_extent_calc_inline_size(size);
+       datasize = btrfs_file_extent_calc_inline_size(offset + size);
 
-       ret = btrfs_insert_empty_item(trans, root, path, &key,
-                                     datasize);
-       if (ret) {
+       ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+       if (ret < 0) {
                err = ret;
                goto fail;
        }
-       leaf = path->nodes[0];
-       ei = btrfs_item_ptr(leaf, path->slots[0],
-                           struct btrfs_file_extent_item);
-       btrfs_set_file_extent_generation(leaf, ei, trans->transid);
-       btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
-       ptr = btrfs_file_extent_inline_start(ei);
-
-       kaddr = kmap_atomic(page, KM_USER1);
-       write_extent_buffer(leaf, kaddr + page_offset, ptr, size);
-       kunmap_atomic(kaddr, KM_USER1);
+       if (ret == 1) {
+               path->slots[0]--;
+               leaf = path->nodes[0];
+               ei = btrfs_item_ptr(leaf, path->slots[0],
+                                   struct btrfs_file_extent_item);
+
+               if (btrfs_file_extent_type(leaf, ei) !=
+                   BTRFS_FILE_EXTENT_INLINE) {
+                       goto insert;
+               }
+               btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+               ret = 0;
+       }
+       if (ret == 0) {
+               u32 found_size;
+               u64 found_start;
+
+               leaf = path->nodes[0];
+               ei = btrfs_item_ptr(leaf, path->slots[0],
+                                   struct btrfs_file_extent_item);
+
+               if (btrfs_file_extent_type(leaf, ei) !=
+                   BTRFS_FILE_EXTENT_INLINE) {
+                       err = ret;
+                       btrfs_print_leaf(root, leaf);
+                       printk("found wasn't inline offset %Lu inode %lu\n",
+                              offset, inode->i_ino);
+                       goto fail;
+               }
+               found_start = key.offset;
+               found_size = btrfs_file_extent_inline_len(leaf,
+                                         btrfs_item_nr(leaf, path->slots[0]));
+
+               if (found_size < offset + size) {
+                       btrfs_release_path(root, path);
+                       ret = btrfs_search_slot(trans, root, &key, path,
+                                               offset + size - found_size -
+                                               found_start, 1);
+                       BUG_ON(ret != 0);
+                       ret = btrfs_extend_item(trans, root, path,
+                                               offset + size - found_size -
+                                               found_start);
+                       if (ret) {
+                               err = ret;
+                               goto fail;
+                       }
+                       leaf = path->nodes[0];
+                       ei = btrfs_item_ptr(leaf, path->slots[0],
+                                           struct btrfs_file_extent_item);
+               }
+       } else {
+insert:
+               btrfs_release_path(root, path);
+               ret = btrfs_insert_empty_item(trans, root, path, &key,
+                                             datasize);
+               if (ret) {
+                       err = ret;
+                       printk("got bad ret %d\n", ret);
+                       goto fail;
+               }
+               leaf = path->nodes[0];
+               ei = btrfs_item_ptr(leaf, path->slots[0],
+                                   struct btrfs_file_extent_item);
+               btrfs_set_file_extent_generation(leaf, ei, trans->transid);
+               btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
+       }
+       ptr = btrfs_file_extent_inline_start(ei) + offset;
+
+       cur_size = size;
+       i = 0;
+       while (size > 0) {
+               page = pages[i];
+               kaddr = kmap_atomic(page, KM_USER0);
+               cur_size = min(PAGE_CACHE_SIZE - page_offset, size);
+               write_extent_buffer(leaf, kaddr + page_offset, ptr, cur_size);
+               kunmap_atomic(kaddr, KM_USER0);
+               page_offset = 0;
+               ptr += cur_size;
+               size -= cur_size;
+               if (i >= num_pages) {
+                       printk("i %d num_pages %d\n", i, num_pages);
+               }
+               i++;
+       }
        btrfs_mark_buffer_dirty(leaf);
 fail:
        btrfs_free_path(path);
@@ -193,6 +269,7 @@ static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
                        err = btrfs_drop_extents(trans, root, inode,
                                                 last_pos_in_file,
                                                 last_pos_in_file + hole_size,
+                                                last_pos_in_file,
                                                 &hint_byte);
                        if (err)
                                goto failed;
@@ -210,11 +287,11 @@ static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
         * either allocate an extent for the new bytes or setup the key
         * to show we are doing inline data in the extent
         */
-       inline_size = end_pos - start_pos;
-       if (isize >= PAGE_CACHE_SIZE || pos + write_bytes < inode->i_size ||
-           inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
-           inline_size >= PAGE_CACHE_SIZE) {
+       inline_size = end_pos;
+       if (isize >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
+           inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root)) {
                u64 last_end;
+
                for (i = 0; i < num_pages; i++) {
                        struct page *p = pages[i];
                        SetPageUptodate(p);
@@ -225,22 +302,18 @@ static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
                set_extent_delalloc(em_tree, start_pos, end_of_last_block,
                                 GFP_NOFS);
        } else {
-               struct page *p = pages[0];
+               u64 aligned_end;
                /* step one, delete the existing extents in this range */
+               aligned_end = (pos + write_bytes + root->sectorsize - 1) &
+                       ~((u64)root->sectorsize - 1);
                err = btrfs_drop_extents(trans, root, inode, start_pos,
-                        (pos + write_bytes + root->sectorsize -1) &
-                        ~((u64)root->sectorsize - 1), &hint_byte);
+                                        aligned_end, end_pos, &hint_byte);
                if (err)
                        goto failed;
-
                err = insert_inline_extent(trans, root, inode, start_pos,
-                                          end_pos - start_pos, p, 0);
+                                          end_pos - start_pos, pages, 0,
+                                          num_pages);
                BUG_ON(err);
-               em->start = start_pos;
-               em->end = end_pos - 1;
-               em->block_start = EXTENT_MAP_INLINE;
-               em->block_end = EXTENT_MAP_INLINE;
-               add_extent_mapping(em_tree, em);
        }
        if (end_pos > isize) {
                i_size_write(inode, end_pos);
@@ -285,7 +358,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
  */
 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
                       struct btrfs_root *root, struct inode *inode,
-                      u64 start, u64 end, u64 *hint_byte)
+                      u64 start, u64 end, u64 inline_end, u64 *hint_byte)
 {
        int ret;
        struct btrfs_key key;
@@ -401,8 +474,8 @@ next_slot:
                                        BUG_ON(ret);
                                }
                        }
-                       WARN_ON(found_inline);
-                       bookend = 1;
+                       if (!found_inline)
+                               bookend = 1;
                }
                /* truncate existing extent */
                if (start > key.offset) {
@@ -425,8 +498,14 @@ next_slot:
                                btrfs_set_file_extent_num_bytes(leaf, extent,
                                                                new_num);
                                btrfs_mark_buffer_dirty(leaf);
-                       } else {
-                               WARN_ON(1);
+                       } else if (end > extent_end &&
+                                  key.offset < inline_end &&
+                                  inline_end < extent_end) {
+                               u32 new_size;
+                               new_size = btrfs_file_extent_calc_inline_size(
+                                                  inline_end - key.offset);
+                               btrfs_truncate_item(trans, root, path,
+                                                   new_size);
                        }
                }
                /* delete the entire extent */
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