[PATCH v7 06/15] iomap: Return error code from iomap_write_iter()

[Stefan Roesch <shr@fb.com>]

Change the signature of iomap_write_iter() to return an error code. In
case we cannot allocate a page in iomap_write_begin(), we will not retry
the memory alloction in iomap_write_begin().

Signed-off-by: Stefan Roesch <shr@fb.com>
---
 fs/iomap/buffered-io.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index b06a5c24a4db..e96ab9a3072c 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -754,12 +754,13 @@ static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
 	return ret;
 }
 
-static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
+static int iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i, loff_t *processed)
 {
 	loff_t length = iomap_length(iter);
 	loff_t pos = iter->pos;
 	ssize_t written = 0;
 	long status = 0;
+	int error = 0;
 	struct address_space *mapping = iter->inode->i_mapping;
 	unsigned int bdp_flags = (iter->flags & IOMAP_NOWAIT) ? BDP_ASYNC : 0;
 
@@ -774,9 +775,9 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
 		bytes = min_t(unsigned long, PAGE_SIZE - offset,
 						iov_iter_count(i));
 again:
-		status = balance_dirty_pages_ratelimited_flags(mapping,
+		error = balance_dirty_pages_ratelimited_flags(mapping,
 							       bdp_flags);
-		if (unlikely(status))
+		if (unlikely(error))
 			break;
 
 		if (bytes > length)
@@ -793,12 +794,12 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
 		 * faulting the user page.
 		 */
 		if (unlikely(fault_in_iov_iter_readable(i, bytes) == bytes)) {
-			status = -EFAULT;
+			error = -EFAULT;
 			break;
 		}
 
-		status = iomap_write_begin(iter, pos, bytes, &folio);
-		if (unlikely(status))
+		error = iomap_write_begin(iter, pos, bytes, &folio);
+		if (unlikely(error))
 			break;
 
 		page = folio_file_page(folio, pos >> PAGE_SHIFT);
@@ -829,7 +830,8 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
 		length -= status;
 	} while (iov_iter_count(i) && length);
 
-	return written ? written : status;
+	*processed = written ? written : error;
+	return error;
 }
 
 ssize_t
@@ -843,12 +845,15 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i,
 		.flags		= IOMAP_WRITE,
 	};
 	int ret;
+	int error = 0;
 
 	if (iocb->ki_flags & IOCB_NOWAIT)
 		iter.flags |= IOMAP_NOWAIT;
 
-	while ((ret = iomap_iter(&iter, ops)) > 0)
-		iter.processed = iomap_write_iter(&iter, i);
+	while ((ret = iomap_iter(&iter, ops)) > 0) {
+		if (error != -EAGAIN)
+			error = iomap_write_iter(&iter, i, &iter.processed);
+	}
 	if (iter.pos == iocb->ki_pos)
 		return ret;
 	return iter.pos - iocb->ki_pos;
-- 
2.30.2