diff options
| -rw-r--r-- | fs/btrfs/ioctl.c | 150 |
1 files changed, 140 insertions, 10 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 7875a75315d..3a89cd77f30 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -475,6 +475,73 @@ out_unlock: return error; } +static int should_defrag_range(struct inode *inode, u64 start, u64 len, + u64 *last_len, u64 *skip, u64 *defrag_end) +{ + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; + struct extent_map *em = NULL; + struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; + int ret = 1; + + /* + * make sure that once we start defragging and extent, we keep on + * defragging it + */ + if (start < *defrag_end) + return 1; + + *skip = 0; + + /* + * hopefully we have this extent in the tree already, try without + * the full extent lock + */ + read_lock(&em_tree->lock); + em = lookup_extent_mapping(em_tree, start, len); + read_unlock(&em_tree->lock); + + if (!em) { + /* get the big lock and read metadata off disk */ + lock_extent(io_tree, start, start + len - 1, GFP_NOFS); + em = btrfs_get_extent(inode, NULL, 0, start, len, 0); + unlock_extent(io_tree, start, start + len - 1, GFP_NOFS); + + if (!em) + return 0; + } + + /* this will cover holes, and inline extents */ + if (em->block_start >= EXTENT_MAP_LAST_BYTE) + ret = 0; + + /* + * we hit a real extent, if it is big don't bother defragging it again + */ + if ((*last_len == 0 || *last_len >= 256 * 1024) && + em->len >= 256 * 1024) + ret = 0; + + /* + * last_len ends up being a counter of how many bytes we've defragged. + * every time we choose not to defrag an extent, we reset *last_len + * so that the next tiny extent will force a defrag. + * + * The end result of this is that tiny extents before a single big + * extent will force at least part of that big extent to be defragged. + */ + if (ret) { + *last_len += len; + *defrag_end = extent_map_end(em); + } else { + *last_len = 0; + *skip = extent_map_end(em); + *defrag_end = 0; + } + + free_extent_map(em); + return ret; +} + static int btrfs_defrag_file(struct file *file) { struct inode *inode = fdentry(file)->d_inode; @@ -487,37 +554,86 @@ static int btrfs_defrag_file(struct file *file) unsigned long total_read = 0; u64 page_start; u64 page_end; + u64 last_len = 0; + u64 skip = 0; + u64 defrag_end = 0; unsigned long i; int ret; - ret = btrfs_check_data_free_space(root, inode, inode->i_size); - if (ret) - return -ENOSPC; + if (inode->i_size == 0) + return 0; + + last_index = (inode->i_size - 1) >> PAGE_CACHE_SHIFT; + i = 0; + while (i <= last_index) { + if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT, + PAGE_CACHE_SIZE, &last_len, &skip, + &defrag_end)) { + unsigned long next; + /* + * the should_defrag function tells us how much to skip + * bump our counter by the suggested amount + */ + next = (skip + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; + i = max(i + 1, next); + continue; + } - mutex_lock(&inode->i_mutex); - last_index = inode->i_size >> PAGE_CACHE_SHIFT; - for (i = 0; i <= last_index; i++) { if (total_read % ra_pages == 0) { btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i, min(last_index, i + ra_pages - 1)); } total_read++; + mutex_lock(&inode->i_mutex); + + ret = btrfs_check_data_free_space(root, inode, PAGE_CACHE_SIZE); + if (ret) { + ret = -ENOSPC; + break; + } + + ret = btrfs_reserve_metadata_for_delalloc(root, inode, 1); + if (ret) { + btrfs_free_reserved_data_space(root, inode, + PAGE_CACHE_SIZE); + ret = -ENOSPC; + break; + } again: + if (inode->i_size == 0 || + i > ((inode->i_size - 1) >> PAGE_CACHE_SHIFT)) { + ret = 0; + goto err_reservations; + } + page = grab_cache_page(inode->i_mapping, i); if (!page) - goto out_unlock; + goto err_reservations; + if (!PageUptodate(page)) { btrfs_readpage(NULL, page); lock_page(page); if (!PageUptodate(page)) { unlock_page(page); page_cache_release(page); - goto out_unlock; + goto err_reservations; } } + if (page->mapping != inode->i_mapping) { + unlock_page(page); + page_cache_release(page); + goto again; + } + wait_on_page_writeback(page); + if (PageDirty(page)) { + btrfs_free_reserved_data_space(root, inode, + PAGE_CACHE_SIZE); + goto loop_unlock; + } + page_start = (u64)page->index << PAGE_CACHE_SHIFT; page_end = page_start + PAGE_CACHE_SIZE - 1; lock_extent(io_tree, page_start, page_end, GFP_NOFS); @@ -538,18 +654,32 @@ again: * page if it is dirtied again later */ clear_page_dirty_for_io(page); + clear_extent_bits(&BTRFS_I(inode)->io_tree, page_start, + page_end, EXTENT_DIRTY | EXTENT_DELALLOC | + EXTENT_DO_ACCOUNTING, GFP_NOFS); btrfs_set_extent_delalloc(inode, page_start, page_end); + ClearPageChecked(page); set_page_dirty(page); unlock_extent(io_tree, page_start, page_end, GFP_NOFS); + +loop_unlock: unlock_page(page); page_cache_release(page); + mutex_unlock(&inode->i_mutex); + + btrfs_unreserve_metadata_for_delalloc(root, inode, 1); balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1); + i++; } -out_unlock: - mutex_unlock(&inode->i_mutex); return 0; + +err_reservations: + mutex_unlock(&inode->i_mutex); + btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE); + btrfs_unreserve_metadata_for_delalloc(root, inode, 1); + return ret; } static noinline int btrfs_ioctl_resize(struct btrfs_root *root, |