[PATCH 07/15] ubifs: Convert write_begin_slow() to use a folio

Matthew Wilcox (Oracle)
2024-01-20T23:08:46Z

Update to new APIs, removing several calls to compound_head() and
including support for large folios.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
fs/ubifs/file.c | 48 ++++++++++++++++++++++++------------------------
1 file changed, 24 insertions(+), 24 deletions(-)

diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 9dfedd91b576..6302ce65e0b3 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -222,16 +222,16 @@ static int write_begin_slow(struct address_space *mapping,
pgoff_t index = pos >> PAGE_SHIFT;
struct ubifs_budget_req req = { .new_page = 1 };
int err, appending = !!(pos + len > inode->i_size);
- struct page *page;
+ struct folio *folio;

dbg_gen("ino %lu, pos %llu, len %u, i_size %lld",
inode->i_ino, pos, len, inode->i_size);

/*
- * At the slow path we have to budget before locking the page, because
- * budgeting may force write-back, which would wait on locked pages and
- * deadlock if we had the page locked. At this point we do not know
- * anything about the page, so assume that this is a new page which is
+ * At the slow path we have to budget before locking the folio, because
+ * budgeting may force write-back, which would wait on locked folios and
+ * deadlock if we had the folio locked. At this point we do not know
+ * anything about the folio, so assume that this is a new folio which is
* written to a hole. This corresponds to largest budget. Later the
* budget will be amended if this is not true.
*/
@@ -243,45 +243,45 @@ static int write_begin_slow(struct address_space *mapping,
if (unlikely(err))
return err;

- page = grab_cache_page_write_begin(mapping, index);
- if (unlikely(!page)) {
+ folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
+ mapping_gfp_mask(mapping));
+ if (IS_ERR(folio)) {
ubifs_release_budget(c, &req);
- return -ENOMEM;
+ return PTR_ERR(folio);
}

- if (!PageUptodate(page)) {
- if (!(pos & ~PAGE_MASK) && len == PAGE_SIZE)
- SetPageChecked(page);
+ if (!folio_test_uptodate(folio)) {
+ if (pos == folio_pos(folio) && len >= folio_size(folio))
+ folio_set_checked(folio);
else {
- err = do_readpage(page);
+ err = do_readpage(&folio->page);
if (err) {
- unlock_page(page);
- put_page(page);
+ folio_unlock(folio);
+ folio_put(folio);
ubifs_release_budget(c, &req);
return err;
}
}

- SetPageUptodate(page);
- ClearPageError(page);
+ folio_mark_uptodate(folio);
}

- if (PagePrivate(page))
+ if (folio->private)
/*
- * The page is dirty, which means it was budgeted twice:
+ * The folio is dirty, which means it was budgeted twice:
* o first time the budget was allocated by the task which
- * made the page dirty and set the PG_private flag;
+ * made the folio dirty and set the private field;
* o and then we budgeted for it for the second time at the
* very beginning of this function.
*
- * So what we have to do is to release the page budget we
+ * So what we have to do is to release the folio budget we
* allocated.
*/
release_new_page_budget(c);
- else if (!PageChecked(page))
+ else if (!folio_test_checked(folio))
/*
- * We are changing a page which already exists on the media.
- * This means that changing the page does not make the amount
+ * We are changing a folio which already exists on the media.
+ * This means that changing the folio does not make the amount
* of indexing information larger, and this part of the budget
* which we have already acquired may be released.
*/
@@ -304,7 +304,7 @@ static int write_begin_slow(struct address_space *mapping,
ubifs_release_dirty_inode_budget(c, ui);
}

- *pagep = page;
+ *pagep = &folio->page;
return 0;
}

--
2.43.0