btrfs: make nodesize >= PAGE_SIZE case to reuse the non-subpage routine

The reason why we only support 64K page size for subpage is, for 64K
page size we can ensure no matter what the nodesize is, we can fit it
into one page.

When other page size come, especially like 16K, the limitation is a bit
limiting.

To remove such limitation, we allow nodesize >= PAGE_SIZE case to go the
non-subpage routine.  By this, we can allow 4K sectorsize on 16K page
size.

Although this introduces another smaller limitation, the metadata can
not cross page boundary, which is already met by most recent mkfs.

Another small improvement is, we can avoid the overhead for metadata if
nodesize >= PAGE_SIZE.
For 4K sector size and 64K page size/node size, or 4K sector size and
16K page size/node size, we don't need to allocate extra memory for the
metadata pages.

Please note that, this patch will not yet enable other page size support
yet.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 67 insertions, 35 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 0dbd59a362c6..f28f059d16b7 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2711,7 +2711,7 @@ static void end_page_read(struct page *page, bool uptodate, u64 start, u32 len)
 		btrfs_page_set_error(fs_info, page, start, len);
 	}
 
-	if (fs_info->sectorsize == PAGE_SIZE)
+	if (!btrfs_is_subpage(fs_info, page))
 		unlock_page(page);
 	else
 		btrfs_subpage_end_reader(fs_info, page, start, len);
@@ -2944,7 +2944,7 @@ update:
 static void begin_page_read(struct btrfs_fs_info *fs_info, struct page *page)
 {
 	ASSERT(PageLocked(page));
-	if (fs_info->sectorsize == PAGE_SIZE)
+	if (!btrfs_is_subpage(fs_info, page))
 		return;
 
 	ASSERT(PagePrivate(page));
@@ -2966,7 +2966,7 @@ static struct extent_buffer *find_extent_buffer_readpage(
 	 * For regular sectorsize, we can use page->private to grab extent
 	 * buffer
 	 */
-	if (fs_info->sectorsize == PAGE_SIZE) {
+	if (fs_info->nodesize >= PAGE_SIZE) {
 		ASSERT(PagePrivate(page) && page->private);
 		return (struct extent_buffer *)page->private;
 	}
@@ -3479,7 +3479,7 @@ static int attach_extent_buffer_page(struct extent_buffer *eb,
 	if (page->mapping)
 		lockdep_assert_held(&page->mapping->private_lock);
 
-	if (fs_info->sectorsize == PAGE_SIZE) {
+	if (fs_info->nodesize >= PAGE_SIZE) {
 		if (!PagePrivate(page))
 			attach_page_private(page, eb);
 		else
@@ -3514,7 +3514,7 @@ int set_page_extent_mapped(struct page *page)
 
 	fs_info = btrfs_sb(page->mapping->host->i_sb);
 
-	if (fs_info->sectorsize < PAGE_SIZE)
+	if (btrfs_is_subpage(fs_info, page))
 		return btrfs_attach_subpage(fs_info, page, BTRFS_SUBPAGE_DATA);
 
 	attach_page_private(page, (void *)EXTENT_PAGE_PRIVATE);
@@ -3531,7 +3531,7 @@ void clear_page_extent_mapped(struct page *page)
 		return;
 
 	fs_info = btrfs_sb(page->mapping->host->i_sb);
-	if (fs_info->sectorsize < PAGE_SIZE)
+	if (btrfs_is_subpage(fs_info, page))
 		return btrfs_detach_subpage(fs_info, page);
 
 	detach_page_private(page);
@@ -3878,7 +3878,7 @@ static void find_next_dirty_byte(struct btrfs_fs_info *fs_info,
 	 * For regular sector size == page size case, since one page only
 	 * contains one sector, we return the page offset directly.
 	 */
-	if (fs_info->sectorsize == PAGE_SIZE) {
+	if (!btrfs_is_subpage(fs_info, page)) {
 		*start = page_offset(page);
 		*end = page_offset(page) + PAGE_SIZE;
 		return;
@@ -4261,7 +4261,7 @@ static noinline_for_stack int lock_extent_buffer_for_io(struct extent_buffer *eb
 	 * Subpage metadata doesn't use page locking at all, so we can skip
 	 * the page locking.
 	 */
-	if (!ret || fs_info->sectorsize < PAGE_SIZE)
+	if (!ret || fs_info->nodesize < PAGE_SIZE)
 		return ret;
 
 	num_pages = num_extent_pages(eb);
@@ -4421,7 +4421,7 @@ static void end_bio_subpage_eb_writepage(struct bio *bio)
 	struct bvec_iter_all iter_all;
 
 	fs_info = btrfs_sb(bio_first_page_all(bio)->mapping->host->i_sb);
-	ASSERT(fs_info->sectorsize < PAGE_SIZE);
+	ASSERT(fs_info->nodesize < PAGE_SIZE);
 
 	ASSERT(!bio_flagged(bio, BIO_CLONED));
 	bio_for_each_segment_all(bvec, bio, iter_all) {
@@ -4748,7 +4748,7 @@ static int submit_eb_page(struct page *page, struct writeback_control *wbc,
 	if (!PagePrivate(page))
 		return 0;
 
-	if (btrfs_sb(page->mapping->host->i_sb)->sectorsize < PAGE_SIZE)
+	if (btrfs_sb(page->mapping->host->i_sb)->nodesize < PAGE_SIZE)
 		return submit_eb_subpage(page, wbc, epd);
 
 	spin_lock(&mapping->private_lock);
@@ -5805,7 +5805,7 @@ static void detach_extent_buffer_page(struct extent_buffer *eb, struct page *pag
 		return;
 	}
 
-	if (fs_info->sectorsize == PAGE_SIZE) {
+	if (fs_info->nodesize >= PAGE_SIZE) {
 		/*
 		 * We do this since we'll remove the pages after we've
 		 * removed the eb from the radix tree, so we could race
@@ -6125,7 +6125,7 @@ static struct extent_buffer *grab_extent_buffer(
 	 * don't try to insert two ebs for the same bytenr.  So here we always
 	 * return NULL and just continue.
 	 */
-	if (fs_info->sectorsize < PAGE_SIZE)
+	if (fs_info->nodesize < PAGE_SIZE)
 		return NULL;
 
 	/* Page not yet attached to an extent buffer */
@@ -6147,6 +6147,30 @@ static struct extent_buffer *grab_extent_buffer(
 	return NULL;
 }
 
+static int check_eb_alignment(struct btrfs_fs_info *fs_info, u64 start)
+{
+	if (!IS_ALIGNED(start, fs_info->sectorsize)) {
+		btrfs_err(fs_info, "bad tree block start %llu", start);
+		return -EINVAL;
+	}
+
+	if (fs_info->nodesize < PAGE_SIZE &&
+	    offset_in_page(start) + fs_info->nodesize > PAGE_SIZE) {
+		btrfs_err(fs_info,
+		"tree block crosses page boundary, start %llu nodesize %u",
+			  start, fs_info->nodesize);
+		return -EINVAL;
+	}
+	if (fs_info->nodesize >= PAGE_SIZE &&
+	    !IS_ALIGNED(start, PAGE_SIZE)) {
+		btrfs_err(fs_info,
+		"tree block is not page aligned, start %llu nodesize %u",
+			  start, fs_info->nodesize);
+		return -EINVAL;
+	}
+	return 0;
+}
+
 struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 					  u64 start, u64 owner_root, int level)
 {
@@ -6161,10 +6185,8 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 	int uptodate = 1;
 	int ret;
 
-	if (!IS_ALIGNED(start, fs_info->sectorsize)) {
-		btrfs_err(fs_info, "bad tree block start %llu", start);
+	if (check_eb_alignment(fs_info, start))
 		return ERR_PTR(-EINVAL);
-	}
 
 #if BITS_PER_LONG == 32
 	if (start >= MAX_LFS_FILESIZE) {
@@ -6177,14 +6199,6 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 		btrfs_warn_32bit_limit(fs_info);
 #endif
 
-	if (fs_info->sectorsize < PAGE_SIZE &&
-	    offset_in_page(start) + len > PAGE_SIZE) {
-		btrfs_err(fs_info,
-		"tree block crosses page boundary, start %llu nodesize %lu",
-			  start, len);
-		return ERR_PTR(-EINVAL);
-	}
-
 	eb = find_extent_buffer(fs_info, start);
 	if (eb)
 		return eb;
@@ -6214,7 +6228,7 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
 		 * page, but it may change in the future for 16K page size
 		 * support, so we still preallocate the memory in the loop.
 		 */
-		if (fs_info->sectorsize < PAGE_SIZE) {
+		if (fs_info->nodesize < PAGE_SIZE) {
 			prealloc = btrfs_alloc_subpage(fs_info, BTRFS_SUBPAGE_METADATA);
 			if (IS_ERR(prealloc)) {
 				ret = PTR_ERR(prealloc);
@@ -6433,7 +6447,7 @@ void clear_extent_buffer_dirty(const struct extent_buffer *eb)
 	int num_pages;
 	struct page *page;
 
-	if (eb->fs_info->sectorsize < PAGE_SIZE)
+	if (eb->fs_info->nodesize < PAGE_SIZE)
 		return clear_subpage_extent_buffer_dirty(eb);
 
 	num_pages = num_extent_pages(eb);
@@ -6465,7 +6479,7 @@ bool set_extent_buffer_dirty(struct extent_buffer *eb)
 	WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
 
 	if (!was_dirty) {
-		bool subpage = eb->fs_info->sectorsize < PAGE_SIZE;
+		bool subpage = eb->fs_info->nodesize < PAGE_SIZE;
 
 		/*
 		 * For subpage case, we can have other extent buffers in the
@@ -6505,9 +6519,18 @@ void clear_extent_buffer_uptodate(struct extent_buffer *eb)
 	num_pages = num_extent_pages(eb);
 	for (i = 0; i < num_pages; i++) {
 		page = eb->pages[i];
-		if (page)
-			btrfs_page_clear_uptodate(fs_info, page,
-						  eb->start, eb->len);
+		if (!page)
+			continue;
+
+		/*
+		 * This is special handling for metadata subpage, as regular
+		 * btrfs_is_subpage() can not handle cloned/dummy metadata.
+		 */
+		if (fs_info->nodesize >= PAGE_SIZE)
+			ClearPageUptodate(page);
+		else
+			btrfs_subpage_clear_uptodate(fs_info, page, eb->start,
+						     eb->len);
 	}
 }
 
@@ -6522,7 +6545,16 @@ void set_extent_buffer_uptodate(struct extent_buffer *eb)
 	num_pages = num_extent_pages(eb);
 	for (i = 0; i < num_pages; i++) {
 		page = eb->pages[i];
-		btrfs_page_set_uptodate(fs_info, page, eb->start, eb->len);
+
+		/*
+		 * This is special handling for metadata subpage, as regular
+		 * btrfs_is_subpage() can not handle cloned/dummy metadata.
+		 */
+		if (fs_info->nodesize >= PAGE_SIZE)
+			SetPageUptodate(page);
+		else
+			btrfs_subpage_set_uptodate(fs_info, page, eb->start,
+						   eb->len);
 	}
 }
 
@@ -6617,7 +6649,7 @@ int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num)
 	if (unlikely(test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)))
 		return -EIO;
 
-	if (eb->fs_info->sectorsize < PAGE_SIZE)
+	if (eb->fs_info->nodesize < PAGE_SIZE)
 		return read_extent_buffer_subpage(eb, wait, mirror_num);
 
 	num_pages = num_extent_pages(eb);
@@ -6872,7 +6904,7 @@ static void assert_eb_page_uptodate(const struct extent_buffer *eb,
 	 * would have !PageUptodate && !PageError, as we clear PageError before
 	 * reading.
 	 */
-	if (fs_info->sectorsize < PAGE_SIZE) {
+	if (fs_info->nodesize < PAGE_SIZE) {
 		bool uptodate, error;
 
 		uptodate = btrfs_subpage_test_uptodate(fs_info, page,
@@ -6974,7 +7006,7 @@ void copy_extent_buffer_full(const struct extent_buffer *dst,
 
 	ASSERT(dst->len == src->len);
 
-	if (dst->fs_info->sectorsize == PAGE_SIZE) {
+	if (dst->fs_info->nodesize >= PAGE_SIZE) {
 		num_pages = num_extent_pages(dst);
 		for (i = 0; i < num_pages; i++)
 			copy_page(page_address(dst->pages[i]),
@@ -6983,7 +7015,7 @@ void copy_extent_buffer_full(const struct extent_buffer *dst,
 		size_t src_offset = get_eb_offset_in_page(src, 0);
 		size_t dst_offset = get_eb_offset_in_page(dst, 0);
 
-		ASSERT(src->fs_info->sectorsize < PAGE_SIZE);
+		ASSERT(src->fs_info->nodesize < PAGE_SIZE);
 		memcpy(page_address(dst->pages[0]) + dst_offset,
 		       page_address(src->pages[0]) + src_offset,
 		       src->len);
@@ -7376,7 +7408,7 @@ int try_release_extent_buffer(struct page *page)
 {
 	struct extent_buffer *eb;
 
-	if (btrfs_sb(page->mapping->host->i_sb)->sectorsize < PAGE_SIZE)
+	if (btrfs_sb(page->mapping->host->i_sb)->nodesize < PAGE_SIZE)
 		return try_release_subpage_extent_buffer(page);
 
 	/*