btrfs: require strict data/metadata split for subpage checks

Since we have btrfs_meta_is_subpage(), we should make btrfs_is_subpage()
to be data inode specific.

This change involves:

- Simplify btrfs_is_subpage()
  Now we only need to do a very simple sectorsize check against
  PAGE_SIZE.
  And since the function is pretty simple now, just make it an inline
  function.

- Add an extra ASSERT() to make sure btrfs_is_subpage() is only called
  on data inode mapping

- Migrate btree_csum_one_bio() to use btrfs_meta_folio_*() helpers
- Migrate alloc_extent_buffer() to use btrfs_meta_folio_*() helpers
- Migrate end_bbio_meta_write() to use btrfs_meta_folio_*() helpers
  Or we will trigger the ASSERT() due to calling btrfs_folio_*() on
  metadata folios.

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

fs/btrfs/disk-io.c

@@ -284,8 +284,8 @@ blk_status_t btree_csum_one_bio(struct btrfs_bio *bbio)
 
 	if (WARN_ON_ONCE(found_start != eb->start))
 		return BLK_STS_IOERR;
-	if (WARN_ON(!btrfs_folio_test_uptodate(fs_info, eb->folios[0],
-					       eb->start, eb->len)))
+	if (WARN_ON(!btrfs_meta_folio_test_uptodate(fs_info, eb->folios[0],
+						    eb->start, eb->len)))
 		return BLK_STS_IOERR;
 
 	ASSERT(memcmp_extent_buffer(eb, fs_info->fs_devices->metadata_uuid,

fs/btrfs/extent_io.c

@@ -1732,18 +1732,14 @@ static void end_bbio_meta_write(struct btrfs_bio *bbio)
 	struct extent_buffer *eb = bbio->private;
 	struct btrfs_fs_info *fs_info = eb->fs_info;
 	struct folio_iter fi;
-	u32 bio_offset = 0;
 
 	if (bbio->bio.bi_status != BLK_STS_OK)
 		set_btree_ioerr(eb);
 
 	bio_for_each_folio_all(fi, &bbio->bio) {
-		u64 start = eb->start + bio_offset;
 		struct folio *folio = fi.folio;
-		u32 len = fi.length;
 
-		btrfs_folio_clear_writeback(fs_info, folio, start, len);
-		bio_offset += len;
+		btrfs_meta_folio_clear_writeback(fs_info, folio, eb->start, eb->len);
 	}
 
 	clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
@@ -3136,7 +3132,7 @@ reallocate:
 		 * and free the allocated page.
 		 */
 		folio = eb->folios[i];
-		WARN_ON(btrfs_folio_test_dirty(fs_info, folio, eb->start, eb->len));
+		WARN_ON(btrfs_meta_folio_test_dirty(fs_info, folio, eb->start, eb->len));
 
 		/*
 		 * Check if the current page is physically contiguous with previous eb
@@ -3147,7 +3143,7 @@ reallocate:
 		if (i && folio_page(eb->folios[i - 1], 0) + 1 != folio_page(folio, 0))
 			page_contig = false;
 
-		if (!btrfs_folio_test_uptodate(fs_info, folio, eb->start, eb->len))
+		if (!btrfs_meta_folio_test_uptodate(fs_info, folio, eb->start, eb->len))
 			uptodate = 0;
 
 		/*

fs/btrfs/subpage.c

@@ -64,30 +64,6 @@
  *   This means a slightly higher tree locking latency.
  */
 
-#if PAGE_SIZE > SZ_4K
-bool btrfs_is_subpage(const struct btrfs_fs_info *fs_info, struct address_space *mapping)
-{
-	if (fs_info->sectorsize >= PAGE_SIZE)
-		return false;
-
-	/*
-	 * Only data pages (either through DIO or compression) can have no
-	 * mapping. And if mapping->host is data inode, it's subpage.
-	 * As we have ruled our sectorsize >= PAGE_SIZE case already.
-	 */
-	if (!mapping || !mapping->host || is_data_inode(BTRFS_I(mapping->host)))
-		return true;
-
-	/*
-	 * Now the only remaining case is metadata, which we only go subpage
-	 * routine if nodesize < PAGE_SIZE.
-	 */
-	if (fs_info->nodesize < PAGE_SIZE)
-		return true;
-	return false;
-}
-#endif
-
 int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info,
 			 struct folio *folio, enum btrfs_subpage_type type)
 {

fs/btrfs/subpage.h

@@ -6,6 +6,7 @@
 #include <linux/spinlock.h>
 #include <linux/atomic.h>
 #include <linux/sizes.h>
+#include "btrfs_inode.h"
 #include "fs.h"
 
 struct address_space;
@@ -83,7 +84,13 @@ static inline bool btrfs_meta_is_subpage(const struct btrfs_fs_info *fs_info)
 {
 	return fs_info->nodesize < PAGE_SIZE;
 }
-bool btrfs_is_subpage(const struct btrfs_fs_info *fs_info, struct address_space *mapping);
+static inline bool btrfs_is_subpage(const struct btrfs_fs_info *fs_info,
+				    struct address_space *mapping)
+{
+	if (mapping && mapping->host)
+		ASSERT(is_data_inode(BTRFS_I(mapping->host)));
+	return fs_info->sectorsize < PAGE_SIZE;
+}
 #else
 static inline bool btrfs_meta_is_subpage(const struct btrfs_fs_info *fs_info)
 {
@@ -92,6 +99,8 @@ static inline bool btrfs_meta_is_subpage(const struct btrfs_fs_info *fs_info)
 static inline bool btrfs_is_subpage(const struct btrfs_fs_info *fs_info,
 				    struct address_space *mapping)
 {
+	if (mapping && mapping->host)
+		ASSERT(is_data_inode(BTRFS_I(mapping->host)));
 	return false;
 }
 #endif