From b9967834ab727f4075b28d79cab881f0db8c3e5d Mon Sep 17 00:00:00 2001
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Date: Tue, 21 Jan 2025 05:40:50 +0000
Subject: [PATCH] btrfs: update some folio related comments
Remove references to the page lock and page->mapping. Also btrfs folios
can never be swizzled into swap (mentioned in extent_write_cache_pages()).
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/extent_io.c | 8 +++-----
fs/btrfs/inode.c | 2 +-
fs/btrfs/subpage.c | 2 +-
3 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index b2fae67f8fa34..112bf48c218c4 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2192,10 +2192,8 @@ static int extent_write_cache_pages(struct address_space *mapping,
done_index = folio_next_index(folio);
/*
* At this point we hold neither the i_pages lock nor
- * the page lock: the page may be truncated or
- * invalidated (changing page->mapping to NULL),
- * or even swizzled back from swapper_space to
- * tmpfs file mapping
+ * the folio lock: the folio may be truncated or
+ * invalidated (changing folio->mapping to NULL).
*/
if (!folio_trylock(folio)) {
submit_write_bio(bio_ctrl, 0);
@@ -3233,7 +3231,7 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
}
/*
* Now all pages of that extent buffer is unmapped, set UNMAPPED flag,
- * so it can be cleaned up without utilizing page->mapping.
+ * so it can be cleaned up without utilizing folio->mapping.
*/
set_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 2a6cddabdd86f..b32112c507070 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2896,7 +2896,7 @@ int btrfs_writepage_cow_fixup(struct folio *folio)
* We are already holding a reference to this inode from
* write_cache_pages. We need to hold it because the space reservation
* takes place outside of the folio lock, and we can't trust
- * page->mapping outside of the folio lock.
+ * folio->mapping outside of the folio lock.
*/
ihold(inode);
btrfs_folio_set_checked(fs_info, folio, folio_pos(folio), folio_size(folio));
diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c
index 722acf768396e..6a8636c0ffed5 100644
--- a/fs/btrfs/subpage.c
+++ b/fs/btrfs/subpage.c
@@ -72,7 +72,7 @@ bool btrfs_is_subpage(const struct btrfs_fs_info *fs_info, struct address_space
/*
* Only data pages (either through DIO or compression) can have no
- * mapping. And if page->mapping->host is data inode, it's subpage.
+ * 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)))