static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb, struct btrfs_file_extent_item *fi, u64 extent_item_pos, struct extent_inode_elem **eie) { u64 offset = 0; struct extent_inode_elem *e; if (!btrfs_file_extent_compression(eb, fi) && !btrfs_file_extent_encryption(eb, fi) && !btrfs_file_extent_other_encoding(eb, fi)) { u64 data_offset; u64 data_len; data_offset = btrfs_file_extent_offset(eb, fi); data_len = btrfs_file_extent_num_bytes(eb, fi); if (extent_item_pos < data_offset || extent_item_pos >= data_offset + data_len) return 1; offset = extent_item_pos - data_offset; } e = kmalloc(sizeof(*e), GFP_NOFS); if (!e) return -ENOMEM; e->next = *eie; e->inum = key->objectid; e->offset = key->offset + offset; *eie = e; return 0; }
/* * this is very complex, but the basic idea is to drop all extents * in the range start - end. hint_block is filled in with a block number * that would be a good hint to the block allocator for this file. * * If an extent intersects the range but is not entirely inside the range * it is either truncated or split. Anything entirely inside the range * is deleted from the tree. * * inline_limit is used to tell this code which offsets in the file to keep * if they contain inline extents. */ noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct inode *inode, u64 start, u64 end, u64 inline_limit, u64 *hint_byte) { u64 extent_end = 0; u64 locked_end = end; u64 search_start = start; u64 leaf_start; u64 ram_bytes = 0; u64 orig_parent = 0; u64 disk_bytenr = 0; u8 compression; u8 encryption; u16 other_encoding = 0; u64 root_gen; u64 root_owner; struct extent_buffer *leaf; struct btrfs_file_extent_item *extent; struct btrfs_path *path; struct btrfs_key key; struct btrfs_file_extent_item old; int keep; int slot; int bookend; int found_type = 0; int found_extent; int found_inline; int recow; int ret; inline_limit = 0; btrfs_drop_extent_cache(inode, start, end - 1, 0); path = btrfs_alloc_path(); if (!path) return -ENOMEM; while (1) { recow = 0; btrfs_release_path(root, path); ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino, search_start, -1); if (ret < 0) goto out; if (ret > 0) { if (path->slots[0] == 0) { ret = 0; goto out; } path->slots[0]--; } next_slot: keep = 0; bookend = 0; found_extent = 0; found_inline = 0; leaf_start = 0; root_gen = 0; root_owner = 0; compression = 0; encryption = 0; extent = NULL; leaf = path->nodes[0]; slot = path->slots[0]; ret = 0; btrfs_item_key_to_cpu(leaf, &key, slot); if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY && key.offset >= end) { goto out; } if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY || key.objectid != inode->i_ino) { goto out; } if (recow) { search_start = max(key.offset, start); continue; } if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) { extent = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); found_type = btrfs_file_extent_type(leaf, extent); compression = btrfs_file_extent_compression(leaf, extent); encryption = btrfs_file_extent_encryption(leaf, extent); other_encoding = btrfs_file_extent_other_encoding(leaf, extent); if (found_type == BTRFS_FILE_EXTENT_REG || found_type == BTRFS_FILE_EXTENT_PREALLOC) { extent_end = btrfs_file_extent_disk_bytenr(leaf, extent); if (extent_end) *hint_byte = extent_end; extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, extent); ram_bytes = btrfs_file_extent_ram_bytes(leaf, extent); found_extent = 1; } else if (found_type == BTRFS_FILE_EXTENT_INLINE) { found_inline = 1; extent_end = key.offset + btrfs_file_extent_inline_len(leaf, extent); } } else {