From: Qu Wenruo Date: Mon, 13 Jan 2025 03:39:24 +0000 (+1030) Subject: btrfs: move ordered extent cleanup to where they are allocated X-Git-Tag: v6.15-rc1~152^2~154 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=94f6c5c17e52a1483aa9197bbdc18730580a6293;p=thirdparty%2Fkernel%2Flinux.git btrfs: move ordered extent cleanup to where they are allocated The ordered extent cleanup is hard to grasp because it doesn't follow the common cleanup-asap pattern. E.g. run_delalloc_nocow() and cow_file_range() allocate one or more ordered extent, but if any error is hit, the cleanup is done later inside btrfs_run_delalloc_range(). To change the existing delayed cleanup: - Update the comment on error handling of run_delalloc_nocow() There are in fact 3 different cases other than 2 if we are doing ordered extents cleanup inside run_delalloc_nocow(): 1) @cow_start and @cow_end not set No fallback to COW at all. Before @cur_offset we need to cleanup the OE and page dirty. After @cur_offset just clear all involved page and extent flags. 2) @cow_start set but @cow_end not set. This means we failed before even calling fallback_to_cow(). It's just a variant of case 1), where it's @cow_start splitting the two parts (and we should just ignore @cur_offset since it's advanced without any new ordered extent). 3) @cow_start and @cow_end both set This means fallback_to_cow() failed, meaning [start, cow_start) needs the regular OE and dirty folio cleanup, and skip range [cow_start, cow_end) as cow_file_range() has done the cleanup, and eventually cleanup [cow_end, end) range. - Only reset @cow_start after fallback_to_cow() succeeded As above case 2) and 3) are both relying on @cow_start to determine the cleanup range. - Move btrfs_cleanup_ordered_extents() into run_delalloc_nocow(), cow_file_range() and nocow_one_range() For cow_file_range() it's pretty straightforward and easy. For run_delalloc_nocow() refer to the above 3 different error cases. For nocow_one_range() if we hit an error, we need to cleanup the ordered extents by ourselves. And then it will fallback to case 1), since @cur_offset is not yet advanced, the existing cleanup will co-operate with nocow_one_range() well. - Remove the btrfs_cleanup_ordered_extents() inside submit_uncompressed_range() As failed cow_file_range() will do all the proper cleanup now. Reviewed-by: Boris Burkov Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 48e5944900c35..f51451402b96f 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1090,7 +1090,6 @@ static void submit_uncompressed_range(struct btrfs_inode *inode, &wbc, false); wbc_detach_inode(&wbc); if (ret < 0) { - btrfs_cleanup_ordered_extents(inode, start, end - start + 1); if (locked_folio) btrfs_folio_end_lock(inode->root->fs_info, locked_folio, start, async_extent->ram_size); @@ -1272,10 +1271,7 @@ u64 btrfs_get_extent_allocation_hint(struct btrfs_inode *inode, u64 start, * - Else all pages except for @locked_folio are unlocked. * * When a failure happens in the second or later iteration of the - * while-loop, the ordered extents created in previous iterations are kept - * intact. So, the caller must clean them up by calling - * btrfs_cleanup_ordered_extents(). See btrfs_run_delalloc_range() for - * example. + * while-loop, the ordered extents created in previous iterations are cleaned up. */ static noinline int cow_file_range(struct btrfs_inode *inode, struct folio *locked_folio, u64 start, @@ -1492,11 +1488,9 @@ out_unlock: /* * For the range (1). We have already instantiated the ordered extents - * for this region. They are cleaned up by - * btrfs_cleanup_ordered_extents() in e.g, - * btrfs_run_delalloc_range(). + * for this region, thus we need to cleanup those ordered extents. * EXTENT_DELALLOC_NEW | EXTENT_DEFRAG | EXTENT_CLEAR_META_RESV - * are also handled by the cleanup function. + * are also handled by the ordered extents cleanup. * * So here we only clear EXTENT_LOCKED and EXTENT_DELALLOC flag, and * finish the writeback of the involved folios, which will be never submitted. @@ -1507,6 +1501,8 @@ out_unlock: if (!locked_folio) mapping_set_error(inode->vfs_inode.i_mapping, ret); + + btrfs_cleanup_ordered_extents(inode, orig_start, start - orig_start); extent_clear_unlock_delalloc(inode, orig_start, start - 1, locked_folio, NULL, clear_bits, page_ops); } @@ -2024,12 +2020,14 @@ static int nocow_one_range(struct btrfs_inode *inode, struct folio *locked_folio EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_CLEAR_DATA_RESV, PAGE_UNLOCK | PAGE_SET_ORDERED); - /* - * btrfs_reloc_clone_csums() error, now we're OK to call error handler, - * as metadata for created ordered extent will only be freed by - * btrfs_finish_ordered_io(). + * On error, we need to cleanup the ordered extents we created. + * + * We do not clear the folio Dirty flags because they are set and + * cleaered by the caller. */ + if (ret < 0) + btrfs_cleanup_ordered_extents(inode, file_pos, end); return ret; } @@ -2208,12 +2206,12 @@ must_cow: if (cow_start != (u64)-1) { ret = fallback_to_cow(inode, locked_folio, cow_start, 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 = (u64)-1; } ret = nocow_one_range(inode, locked_folio, &cached_state, @@ -2231,11 +2229,11 @@ must_cow: if (cow_start != (u64)-1) { ret = fallback_to_cow(inode, locked_folio, cow_start, end); - cow_start = (u64)-1; if (ret) { cow_end = end; goto error; } + cow_start = (u64)-1; } btrfs_free_path(path); @@ -2249,27 +2247,44 @@ error: * start cur_offset end * |/////////////| | * + * In this case, cow_start should be (u64)-1. + * * 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(). + * Need to clear the dirty flags and finish the ordered extents. + * + * 2) Failed with error before calling fallback_to_cow() + * + * start cow_start end + * |/////////////| | + * + * In this case, only @cow_start is set, @cur_offset is between + * [cow_start, end) + * + * It's mostly the same as case 1), just replace @cur_offset with + * @cow_start. * - * 2) Failed with error from fallback_to_cow() - * start cur_offset cow_end end + * 3) Failed with error from fallback_to_cow() + * + * start cow_start 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(). + * In this case, both @cow_start and @cow_end is set. * - * Thus we should not call extent_clear_unlock_delalloc() on range - * [cur_offset, cow_end), as the folios are already unlocked. + * For range [start, cow_start) it's the same as case 1). + * But for range [cow_start, cow_end), all the cleanup is handled by + * cow_file_range(), we should not touch anything in that range. * - * So clear the folio dirty flags for [start, cur_offset) first. + * So for all above cases, if @cow_start is set, cleanup ordered extents + * for range [start, @cow_start), other wise cleanup range [start, @cur_offset). */ - if (cur_offset > start) + if (cow_start != (u64)-1) + cur_offset = cow_start; + + if (cur_offset > start) { + btrfs_cleanup_ordered_extents(inode, start, 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 @@ -2334,7 +2349,7 @@ int btrfs_run_delalloc_range(struct btrfs_inode *inode, struct folio *locked_fol if (should_nocow(inode, start, end)) { ret = run_delalloc_nocow(inode, locked_folio, start, end); - goto out; + return ret; } if (btrfs_inode_can_compress(inode) && @@ -2348,10 +2363,6 @@ int btrfs_run_delalloc_range(struct btrfs_inode *inode, struct folio *locked_fol else ret = cow_file_range(inode, locked_folio, start, end, NULL, false, false); - -out: - if (ret < 0) - btrfs_cleanup_ordered_extents(inode, start, end - start + 1); return ret; }