btrfs: fix dirty_metadata_bytes for redirtied buffers

dirty_metadata_bytes is decremented in both places that clear the dirty
bit in a buffer, but only incremented in btrfs_mark_buffer_dirty, which
means that a buffer that is redirtied using btrfs_redirty_list_add won't
be added to dirty_metadata_bytes, but it will be subtracted when written
out, leading an inconsistency in the counter.

Move the dirty_metadata_bytes from btrfs_mark_buffer_dirty into
set_extent_buffer_dirty to also account for the redirty case, and remove
the now unused set_extent_buffer_dirty return value.

Fixes: d3575156 ("btrfs: zoned: redirty released extent buffers")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

@@ -4621,7 +4621,6 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
 {
 	struct btrfs_fs_info *fs_info = buf->fs_info;
 	u64 transid = btrfs_header_generation(buf);
-	int was_dirty;
 
 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 	/*
@@ -4636,11 +4635,7 @@ void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
 	if (transid != fs_info->generation)
 		WARN(1, KERN_CRIT "btrfs transid mismatch buffer %llu, found %llu running %llu\n",
 			buf->start, transid, fs_info->generation);
-	was_dirty = set_extent_buffer_dirty(buf);
-	if (!was_dirty)
-		percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
-					 buf->len,
-					 fs_info->dirty_metadata_batch);
+	set_extent_buffer_dirty(buf);
 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
 	/*
 	 * btrfs_check_leaf() won't check item data if we don't have WRITTEN

fs/btrfs/extent_io.c

@@ -4148,7 +4148,7 @@ void btrfs_clear_buffer_dirty(struct btrfs_trans_handle *trans,
 	WARN_ON(atomic_read(&eb->refs) == 0);
 }
 
-bool set_extent_buffer_dirty(struct extent_buffer *eb)
+void set_extent_buffer_dirty(struct extent_buffer *eb)
 {
 	int i;
 	int num_pages;
@@ -4183,13 +4183,14 @@ bool set_extent_buffer_dirty(struct extent_buffer *eb)
 					     eb->start, eb->len);
 		if (subpage)
 			unlock_page(eb->pages[0]);
+		percpu_counter_add_batch(&eb->fs_info->dirty_metadata_bytes,
+					 eb->len,
+					 eb->fs_info->dirty_metadata_batch);
 	}
 #ifdef CONFIG_BTRFS_DEBUG
 	for (i = 0; i < num_pages; i++)
 		ASSERT(PageDirty(eb->pages[i]));
 #endif
-
-	return was_dirty;
 }
 
 void clear_extent_buffer_uptodate(struct extent_buffer *eb)

fs/btrfs/extent_io.h

@@ -262,7 +262,7 @@ void extent_buffer_bitmap_set(const struct extent_buffer *eb, unsigned long star
 void extent_buffer_bitmap_clear(const struct extent_buffer *eb,
 				unsigned long start, unsigned long pos,
 				unsigned long len);
-bool set_extent_buffer_dirty(struct extent_buffer *eb);
+void set_extent_buffer_dirty(struct extent_buffer *eb);
 void set_extent_buffer_uptodate(struct extent_buffer *eb);
 void clear_extent_buffer_uptodate(struct extent_buffer *eb);
 int extent_buffer_under_io(const struct extent_buffer *eb);