return ret < 0 ? ret : can_nocow;
}
+/*
+ * Cleanup the dirty folios which will never be submitted due to error.
+ *
+ * When running a delalloc range, we may need to split the ranges (due to
+ * fragmentation or NOCOW). If we hit an error in the later part, we will error
+ * out and previously successfully executed range will never be submitted, thus
+ * we have to cleanup those folios by clearing their dirty flag, starting and
+ * finishing the writeback.
+ */
+static void cleanup_dirty_folios(struct btrfs_inode *inode,
+ struct folio *locked_folio,
+ u64 start, u64 end, int error)
+{
+ struct btrfs_fs_info *fs_info = inode->root->fs_info;
+ struct address_space *mapping = inode->vfs_inode.i_mapping;
+ pgoff_t start_index = start >> PAGE_SHIFT;
+ pgoff_t end_index = end >> PAGE_SHIFT;
+ u32 len;
+
+ ASSERT(end + 1 - start < U32_MAX);
+ ASSERT(IS_ALIGNED(start, fs_info->sectorsize) &&
+ IS_ALIGNED(end + 1, fs_info->sectorsize));
+ len = end + 1 - start;
+
+ /*
+ * Handle the locked folio first.
+ * The btrfs_folio_clamp_*() helpers can handle range out of the folio case.
+ */
+ btrfs_folio_clamp_finish_io(fs_info, locked_folio, start, len);
+
+ for (pgoff_t index = start_index; index <= end_index; index++) {
+ struct folio *folio;
+
+ /* Already handled at the beginning. */
+ if (index == locked_folio->index)
+ continue;
+ folio = __filemap_get_folio(mapping, index, FGP_LOCK, GFP_NOFS);
+ /* Cache already dropped, no need to do any cleanup. */
+ if (IS_ERR(folio))
+ continue;
+ btrfs_folio_clamp_finish_io(fs_info, locked_folio, start, len);
+ folio_unlock(folio);
+ folio_put(folio);
+ }
+ mapping_set_error(mapping, error);
+}
+
/*
* when nowcow writeback call back. This checks for snapshots or COW copies
* of the extents that exist in the file, and COWs the file as required.
struct btrfs_root *root = inode->root;
struct btrfs_path *path;
u64 cow_start = (u64)-1;
+ /*
+ * If not 0, represents the inclusive end of the last fallback_to_cow()
+ * range. Only for error handling.
+ */
+ u64 cow_end = 0;
u64 cur_offset = start;
int ret;
bool check_prev = true;
found_key.offset - 1);
cow_start = (u64)-1;
if (ret) {
+ cow_end = found_key.offset - 1;
btrfs_dec_nocow_writers(nocow_bg);
goto error;
}
cow_start = cur_offset;
if (cow_start != (u64)-1) {
- cur_offset = end;
ret = fallback_to_cow(inode, locked_folio, cow_start, end);
cow_start = (u64)-1;
- if (ret)
+ if (ret) {
+ cow_end = end;
goto error;
+ }
}
btrfs_free_path(path);
return 0;
error:
+ /*
+ * There are several error cases:
+ *
+ * 1) Failed without falling back to COW
+ * start cur_offset end
+ * |/////////////| |
+ *
+ * For range [start, cur_offset) the folios are already unlocked (except
+ * @locked_folio), EXTENT_DELALLOC already removed.
+ * Only need to clear the dirty flag as they will never be submitted.
+ * Ordered extent and extent maps are handled by
+ * btrfs_mark_ordered_io_finished() inside run_delalloc_range().
+ *
+ * 2) Failed with error from fallback_to_cow()
+ * start cur_offset cow_end end
+ * |/////////////|-----------| |
+ *
+ * For range [start, cur_offset) it's the same as case 1).
+ * But for range [cur_offset, cow_end), the folios have dirty flag
+ * cleared and unlocked, EXTENT_DEALLLOC cleared by cow_file_range().
+ *
+ * Thus we should not call extent_clear_unlock_delalloc() on range
+ * [cur_offset, cow_end), as the folios are already unlocked.
+ *
+ * So clear the folio dirty flags for [start, cur_offset) first.
+ */
+ if (cur_offset > start)
+ cleanup_dirty_folios(inode, locked_folio, start, cur_offset - 1, ret);
+
/*
* If an error happened while a COW region is outstanding, cur_offset
- * needs to be reset to cow_start to ensure the COW region is unlocked
- * as well.
+ * needs to be reset to @cow_end + 1 to skip the COW range, as
+ * cow_file_range() will do the proper cleanup at error.
*/
- if (cow_start != (u64)-1)
- cur_offset = cow_start;
+ if (cow_end)
+ cur_offset = cow_end + 1;
/*
* We need to lock the extent here because we're clearing DELALLOC and
DECLARE_BTRFS_SUBPAGE_OPS(ordered);
DECLARE_BTRFS_SUBPAGE_OPS(checked);
+/*
+ * Helper for error cleanup, where a folio will have its dirty flag cleared,
+ * with writeback started and finished.
+ */
+static inline void btrfs_folio_clamp_finish_io(struct btrfs_fs_info *fs_info,
+ struct folio *locked_folio,
+ u64 start, u32 len)
+{
+ btrfs_folio_clamp_clear_dirty(fs_info, locked_folio, start, len);
+ btrfs_folio_clamp_set_writeback(fs_info, locked_folio, start, len);
+ btrfs_folio_clamp_clear_writeback(fs_info, locked_folio, start, len);
+}
+
bool btrfs_subpage_clear_and_test_dirty(const struct btrfs_fs_info *fs_info,
struct folio *folio, u64 start, u32 len);
projects / linux-block.git / commitdiff