From: Qu Wenruo <wqu@suse.com>
Date: Tue, 28 Jan 2025 05:24:40 +0000 (+1030)
Subject: btrfs: make subpage attach and detach handle metadata properly
X-Git-Tag: v6.15-rc1~152^2~150
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=57a3212674f40c6700f3a50d16432239a7c8e617;p=thirdparty%2Fkernel%2Flinux.git

btrfs: make subpage attach and detach handle metadata properly

Currently subpage attach/detach is not doing proper dummy extent buffer
subpage check, as btrfs_is_subpage() is not reliable for dummy extent
buffer folios.

Since we have a metadata specific check now, use that for
btrfs_attach_subpage() first.

Then enhance btrfs_detach_subpage() to accept a type parameter, so that
we can do extra checks for dummy extent buffers properly.

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

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index c1afd8aab77c2..089fb6cecbba5 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -888,7 +888,7 @@ void clear_folio_extent_mapped(struct folio *folio)
 
 	fs_info = folio_to_fs_info(folio);
 	if (btrfs_is_subpage(fs_info, folio->mapping))
-		return btrfs_detach_subpage(fs_info, folio);
+		return btrfs_detach_subpage(fs_info, folio, BTRFS_SUBPAGE_DATA);
 
 	folio_detach_private(folio);
 }
@@ -2622,7 +2622,7 @@ static void detach_extent_buffer_folio(const struct extent_buffer *eb, struct fo
 	 * attached to one dummy eb, no sharing.
 	 */
 	if (!mapped) {
-		btrfs_detach_subpage(fs_info, folio);
+		btrfs_detach_subpage(fs_info, folio, BTRFS_SUBPAGE_METADATA);
 		return;
 	}
 
@@ -2633,7 +2633,7 @@ static void detach_extent_buffer_folio(const struct extent_buffer *eb, struct fo
 	 * page range and no unfinished IO.
 	 */
 	if (!folio_range_has_eb(folio))
-		btrfs_detach_subpage(fs_info, folio);
+		btrfs_detach_subpage(fs_info, folio, BTRFS_SUBPAGE_METADATA);
 
 	spin_unlock(&folio->mapping->i_private_lock);
 }
diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c
index e34694f0cdcc9..073eca132292f 100644
--- a/fs/btrfs/subpage.c
+++ b/fs/btrfs/subpage.c
@@ -104,7 +104,11 @@ int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info,
 		ASSERT(folio_test_locked(folio));
 
 	/* Either not subpage, or the folio already has private attached. */
-	if (!btrfs_is_subpage(fs_info, folio->mapping) || folio_test_private(folio))
+	if (folio_test_private(folio))
+		return 0;
+	if (type == BTRFS_SUBPAGE_METADATA && !btrfs_meta_is_subpage(fs_info))
+		return 0;
+	if (type == BTRFS_SUBPAGE_DATA && !btrfs_is_subpage(fs_info, folio->mapping))
 		return 0;
 
 	subpage = btrfs_alloc_subpage(fs_info, type);
@@ -115,12 +119,17 @@ int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info,
 	return 0;
 }
 
-void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info, struct folio *folio)
+void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info, struct folio *folio,
+			  enum btrfs_subpage_type type)
 {
 	struct btrfs_subpage *subpage;
 
 	/* Either not subpage, or the folio already has private attached. */
-	if (!btrfs_is_subpage(fs_info, folio->mapping) || !folio_test_private(folio))
+	if (!folio_test_private(folio))
+		return;
+	if (type == BTRFS_SUBPAGE_METADATA && !btrfs_meta_is_subpage(fs_info))
+		return;
+	if (type == BTRFS_SUBPAGE_DATA && !btrfs_is_subpage(fs_info, folio->mapping))
 		return;
 
 	subpage = folio_detach_private(folio);
diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h
index 7aacf5ff02969..4de61ee938592 100644
--- a/fs/btrfs/subpage.h
+++ b/fs/btrfs/subpage.h
@@ -98,7 +98,8 @@ static inline bool btrfs_is_subpage(const struct btrfs_fs_info *fs_info,
 
 int btrfs_attach_subpage(const struct btrfs_fs_info *fs_info,
 			 struct folio *folio, enum btrfs_subpage_type type);
-void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info, struct folio *folio);
+void btrfs_detach_subpage(const struct btrfs_fs_info *fs_info, struct folio *folio,
+			  enum btrfs_subpage_type type);
 
 /* Allocate additional data where page represents more than one sector */
 struct btrfs_subpage *btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info,