[PATCH 12/12] iomap: build the writeback code without CONFIG_BLOCK

Christoph Hellwig
2025-06-27T07:04:08Z

Allow fuse to use the iomap writeback code even when CONFIG_BLOCK is
not enabled. Do this with an ifdef instead of a separate file to keep
the iomap_folio_state local to buffered-io.c.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/iomap/Makefile | 6 +--
fs/iomap/buffered-io.c | 113 ++++++++++++++++++++++-------------------
2 files changed, 64 insertions(+), 55 deletions(-)

diff --git a/fs/iomap/Makefile b/fs/iomap/Makefile
index 69e8ebb41302..f7e1c8534c46 100644
--- a/fs/iomap/Makefile
+++ b/fs/iomap/Makefile
@@ -9,9 +9,9 @@ ccflags-y += -I $(src) # needed for trace events
obj-$(CONFIG_FS_IOMAP) += iomap.o

iomap-y += trace.o \
- iter.o
-iomap-$(CONFIG_BLOCK) += buffered-io.o \
- direct-io.o \
+ iter.o \
+ buffered-io.o
+iomap-$(CONFIG_BLOCK) += direct-io.o \
ioend.o \
fiemap.o \
seek.o
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 1a9ade77aeeb..6ceeb0e2fc13 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -284,6 +284,46 @@ static void iomap_adjust_read_range(struct inode *inode, struct folio *folio,
*lenp = plen;
}

+static inline bool iomap_block_needs_zeroing(const struct iomap_iter *iter,
+ loff_t pos)
+{
+ const struct iomap *srcmap = iomap_iter_srcmap(iter);
+
+ return srcmap->type != IOMAP_MAPPED ||
+ (srcmap->flags & IOMAP_F_NEW) ||
+ pos >= i_size_read(iter->inode);
+}
+
+/**
+ * iomap_read_inline_data - copy inline data into the page cache
+ * @iter: iteration structure
+ * @folio: folio to copy to
+ *
+ * Copy the inline data in @iter into @folio and zero out the rest of the folio.
+ * Only a single IOMAP_INLINE extent is allowed at the end of each file.
+ * Returns zero for success to complete the read, or the usual negative errno.
+ */
+static int iomap_read_inline_data(const struct iomap_iter *iter,
+ struct folio *folio)
+{
+ const struct iomap *iomap = iomap_iter_srcmap(iter);
+ size_t size = i_size_read(iter->inode) - iomap->offset;
+ size_t offset = offset_in_folio(folio, iomap->offset);
+
+ if (folio_test_uptodate(folio))
+ return 0;
+
+ if (WARN_ON_ONCE(size > iomap->length))
+ return -EIO;
+ if (offset > 0)
+ ifs_alloc(iter->inode, folio, iter->flags);
+
+ folio_fill_tail(folio, offset, iomap->inline_data, size);
+ iomap_set_range_uptodate(folio, offset, folio_size(folio) - offset);
+ return 0;
+}
+
+#ifdef CONFIG_BLOCK
static void iomap_finish_folio_read(struct folio *folio, size_t off,
size_t len, int error)
{
@@ -323,45 +363,6 @@ struct iomap_readpage_ctx {
struct readahead_control *rac;
};

-/**
- * iomap_read_inline_data - copy inline data into the page cache
- * @iter: iteration structure
- * @folio: folio to copy to
- *
- * Copy the inline data in @iter into @folio and zero out the rest of the folio.
- * Only a single IOMAP_INLINE extent is allowed at the end of each file.
- * Returns zero for success to complete the read, or the usual negative errno.
- */
-static int iomap_read_inline_data(const struct iomap_iter *iter,
- struct folio *folio)
-{
- const struct iomap *iomap = iomap_iter_srcmap(iter);
- size_t size = i_size_read(iter->inode) - iomap->offset;
- size_t offset = offset_in_folio(folio, iomap->offset);
-
- if (folio_test_uptodate(folio))
- return 0;
-
- if (WARN_ON_ONCE(size > iomap->length))
- return -EIO;
- if (offset > 0)
- ifs_alloc(iter->inode, folio, iter->flags);
-
- folio_fill_tail(folio, offset, iomap->inline_data, size);
- iomap_set_range_uptodate(folio, offset, folio_size(folio) - offset);
- return 0;
-}
-
-static inline bool iomap_block_needs_zeroing(const struct iomap_iter *iter,
- loff_t pos)
-{
- const struct iomap *srcmap = iomap_iter_srcmap(iter);
-
- return srcmap->type != IOMAP_MAPPED ||
- (srcmap->flags & IOMAP_F_NEW) ||
- pos >= i_size_read(iter->inode);
-}
-
static int iomap_readpage_iter(struct iomap_iter *iter,
struct iomap_readpage_ctx *ctx)
{
@@ -554,6 +555,27 @@ void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops)
}
EXPORT_SYMBOL_GPL(iomap_readahead);

+static int iomap_read_folio_range(const struct iomap_iter *iter,
+ struct folio *folio, loff_t pos, size_t len)
+{
+ const struct iomap *srcmap = iomap_iter_srcmap(iter);
+ struct bio_vec bvec;
+ struct bio bio;
+
+ bio_init(&bio, srcmap->bdev, &bvec, 1, REQ_OP_READ);
+ bio.bi_iter.bi_sector = iomap_sector(srcmap, pos);
+ bio_add_folio_nofail(&bio, folio, len, offset_in_folio(folio, pos));
+ return submit_bio_wait(&bio);
+}
+#else
+static int iomap_read_folio_range(const struct iomap_iter *iter,
+ struct folio *folio, loff_t pos, size_t len)
+{
+ WARN_ON_ONCE(1);
+ return -EIO;
+}
+#endif /* CONFIG_BLOCK */
+
/*
* iomap_is_partially_uptodate checks whether blocks within a folio are
* uptodate or not.
@@ -667,19 +689,6 @@ iomap_write_failed(struct inode *inode, loff_t pos, unsigned len)
pos + len - 1);
}

-static int iomap_read_folio_range(const struct iomap_iter *iter,
- struct folio *folio, loff_t pos, size_t len)
-{
- const struct iomap *srcmap = iomap_iter_srcmap(iter);
- struct bio_vec bvec;
- struct bio bio;
-
- bio_init(&bio, srcmap->bdev, &bvec, 1, REQ_OP_READ);
- bio.bi_iter.bi_sector = iomap_sector(srcmap, pos);
- bio_add_folio_nofail(&bio, folio, len, offset_in_folio(folio, pos));
- return submit_bio_wait(&bio);
-}
-
static int __iomap_write_begin(const struct iomap_iter *iter,
const struct iomap_write_ops *write_ops, size_t len,
struct folio *folio)
--
2.47.2