Btrfs: Add fallocate support v2
[pandora-kernel.git] / fs / btrfs / file.c
index 1a0510a..238a8e2 100644 (file)
@@ -381,7 +381,7 @@ int noinline btrfs_drop_extents(struct btrfs_trans_handle *trans,
        int keep;
        int slot;
        int bookend;
-       int found_type;
+       int found_type = 0;
        int found_extent;
        int found_inline;
        int recow;
@@ -442,7 +442,8 @@ next_slot:
                                                                  extent);
                        other_encoding = btrfs_file_extent_other_encoding(leaf,
                                                                  extent);
-                       if (found_type == BTRFS_FILE_EXTENT_REG) {
+                       if (found_type == BTRFS_FILE_EXTENT_REG ||
+                           found_type == BTRFS_FILE_EXTENT_PREALLOC) {
                                extent_end =
                                     btrfs_file_extent_disk_bytenr(leaf,
                                                                   extent);
@@ -609,8 +610,7 @@ next_slot:
                         */
                        btrfs_set_file_extent_ram_bytes(leaf, extent,
                                                        ram_bytes);
-                       btrfs_set_file_extent_type(leaf, extent,
-                                                  BTRFS_FILE_EXTENT_REG);
+                       btrfs_set_file_extent_type(leaf, extent, found_type);
 
                        btrfs_mark_buffer_dirty(path->nodes[0]);
 
@@ -661,6 +661,243 @@ out:
        return ret;
 }
 
+static int extent_mergeable(struct extent_buffer *leaf, int slot,
+                           u64 objectid, u64 bytenr, u64 *start, u64 *end)
+{
+       struct btrfs_file_extent_item *fi;
+       struct btrfs_key key;
+       u64 extent_end;
+
+       if (slot < 0 || slot >= btrfs_header_nritems(leaf))
+               return 0;
+
+       btrfs_item_key_to_cpu(leaf, &key, slot);
+       if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
+               return 0;
+
+       fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
+       if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
+           btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
+           btrfs_file_extent_compression(leaf, fi) ||
+           btrfs_file_extent_encryption(leaf, fi) ||
+           btrfs_file_extent_other_encoding(leaf, fi))
+               return 0;
+
+       extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
+       if ((*start && *start != key.offset) || (*end && *end != extent_end))
+               return 0;
+
+       *start = key.offset;
+       *end = extent_end;
+       return 1;
+}
+
+/*
+ * Mark extent in the range start - end as written.
+ *
+ * This changes extent type from 'pre-allocated' to 'regular'. If only
+ * part of extent is marked as written, the extent will be split into
+ * two or three.
+ */
+int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
+                             struct btrfs_root *root,
+                             struct inode *inode, u64 start, u64 end)
+{
+       struct extent_buffer *leaf;
+       struct btrfs_path *path;
+       struct btrfs_file_extent_item *fi;
+       struct btrfs_key key;
+       u64 bytenr;
+       u64 num_bytes;
+       u64 extent_end;
+       u64 extent_offset;
+       u64 other_start;
+       u64 other_end;
+       u64 split = start;
+       u64 locked_end = end;
+       int extent_type;
+       int split_end = 1;
+       int ret;
+
+       btrfs_drop_extent_cache(inode, start, end - 1, 0);
+
+       path = btrfs_alloc_path();
+       BUG_ON(!path);
+again:
+       key.objectid = inode->i_ino;
+       key.type = BTRFS_EXTENT_DATA_KEY;
+       if (split == start)
+               key.offset = split;
+       else
+               key.offset = split - 1;
+
+       ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+       if (ret > 0 && path->slots[0] > 0)
+               path->slots[0]--;
+
+       leaf = path->nodes[0];
+       btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+       BUG_ON(key.objectid != inode->i_ino ||
+              key.type != BTRFS_EXTENT_DATA_KEY);
+       fi = btrfs_item_ptr(leaf, path->slots[0],
+                           struct btrfs_file_extent_item);
+       extent_type = btrfs_file_extent_type(leaf, fi);
+       BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
+       extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
+       BUG_ON(key.offset > start || extent_end < end);
+
+       bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+       num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
+       extent_offset = btrfs_file_extent_offset(leaf, fi);
+
+       if (key.offset == start)
+               split = end;
+
+       if (key.offset == start && extent_end == end) {
+               int del_nr = 0;
+               int del_slot = 0;
+               u64 leaf_owner = btrfs_header_owner(leaf);
+               u64 leaf_gen = btrfs_header_generation(leaf);
+               other_start = end;
+               other_end = 0;
+               if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
+                                    bytenr, &other_start, &other_end)) {
+                       extent_end = other_end;
+                       del_slot = path->slots[0] + 1;
+                       del_nr++;
+                       ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
+                                               leaf->start, leaf_owner,
+                                               leaf_gen, inode->i_ino, 0);
+                       BUG_ON(ret);
+               }
+               other_start = 0;
+               other_end = start;
+               if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
+                                    bytenr, &other_start, &other_end)) {
+                       key.offset = other_start;
+                       del_slot = path->slots[0];
+                       del_nr++;
+                       ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
+                                               leaf->start, leaf_owner,
+                                               leaf_gen, inode->i_ino, 0);
+                       BUG_ON(ret);
+               }
+               split_end = 0;
+               if (del_nr == 0) {
+                       btrfs_set_file_extent_type(leaf, fi,
+                                                  BTRFS_FILE_EXTENT_REG);
+                       goto done;
+               }
+
+               fi = btrfs_item_ptr(leaf, del_slot - 1,
+                                   struct btrfs_file_extent_item);
+               btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
+               btrfs_set_file_extent_num_bytes(leaf, fi,
+                                               extent_end - key.offset);
+               btrfs_mark_buffer_dirty(leaf);
+
+               ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
+               BUG_ON(ret);
+               goto done;
+       } else if (split == start) {
+               if (locked_end < extent_end) {
+                       ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
+                                       locked_end, extent_end - 1, GFP_NOFS);
+                       if (!ret) {
+                               btrfs_release_path(root, path);
+                               lock_extent(&BTRFS_I(inode)->io_tree,
+                                       locked_end, extent_end - 1, GFP_NOFS);
+                               locked_end = extent_end;
+                               goto again;
+                       }
+                       locked_end = extent_end;
+               }
+               btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
+               extent_offset += split - key.offset;
+       } else  {
+               BUG_ON(key.offset != start);
+               btrfs_set_file_extent_offset(leaf, fi, extent_offset +
+                                            split - key.offset);
+               btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
+               key.offset = split;
+               btrfs_set_item_key_safe(trans, root, path, &key);
+               extent_end = split;
+       }
+
+       if (extent_end == end) {
+               split_end = 0;
+               extent_type = BTRFS_FILE_EXTENT_REG;
+       }
+       if (extent_end == end && split == start) {
+               other_start = end;
+               other_end = 0;
+               if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
+                                    bytenr, &other_start, &other_end)) {
+                       path->slots[0]++;
+                       fi = btrfs_item_ptr(leaf, path->slots[0],
+                                           struct btrfs_file_extent_item);
+                       key.offset = split;
+                       btrfs_set_item_key_safe(trans, root, path, &key);
+                       btrfs_set_file_extent_offset(leaf, fi, extent_offset);
+                       btrfs_set_file_extent_num_bytes(leaf, fi,
+                                                       other_end - split);
+                       goto done;
+               }
+       }
+       if (extent_end == end && split == end) {
+               other_start = 0;
+               other_end = start;
+               if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
+                                    bytenr, &other_start, &other_end)) {
+                       path->slots[0]--;
+                       fi = btrfs_item_ptr(leaf, path->slots[0],
+                                           struct btrfs_file_extent_item);
+                       btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
+                                                       other_start);
+                       goto done;
+               }
+       }
+
+       btrfs_mark_buffer_dirty(leaf);
+       btrfs_release_path(root, path);
+
+       key.offset = start;
+       ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
+       BUG_ON(ret);
+
+       leaf = path->nodes[0];
+       fi = btrfs_item_ptr(leaf, path->slots[0],
+                           struct btrfs_file_extent_item);
+       btrfs_set_file_extent_generation(leaf, fi, trans->transid);
+       btrfs_set_file_extent_type(leaf, fi, extent_type);
+       btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
+       btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
+       btrfs_set_file_extent_offset(leaf, fi, extent_offset);
+       btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
+       btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
+       btrfs_set_file_extent_compression(leaf, fi, 0);
+       btrfs_set_file_extent_encryption(leaf, fi, 0);
+       btrfs_set_file_extent_other_encoding(leaf, fi, 0);
+
+       ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
+                                  leaf->start, root->root_key.objectid,
+                                  trans->transid, inode->i_ino);
+       BUG_ON(ret);
+done:
+       btrfs_mark_buffer_dirty(leaf);
+       btrfs_release_path(root, path);
+       if (split_end && split == start) {
+               split = end;
+               goto again;
+       }
+       if (locked_end > end) {
+               unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
+                             GFP_NOFS);
+       }
+       btrfs_free_path(path);
+       return 0;
+}
+
 /*
  * this gets pages into the page cache and locks them down, it also properly
  * waits for data=ordered extents to finish before allowing the pages to be