From: Qu Wenruo <wqu@suse.com>
Date: Mon, 17 Mar 2025 07:10:47 +0000 (+1030)
Subject: btrfs: send: prepare put_file_data() for large data folios
X-Git-Tag: v6.16-rc1~214^2~159
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a4a636a43741c2706868fb97dff9a83d398ac9e3;p=thirdparty%2Flinux.git

btrfs: send: prepare put_file_data() for large data folios

Currently put_file_data() can only accept a page sized folio.  However
the function itself is not that complex, it's just copying data from
filemap folio into the send buffer.

Make it support large data folios:

- Change the loop to use file offset instead of page index

- Calculate @pg_offset and @cur_len after getting the folio

- Remove the "WARN_ON(folio_order(folio));" line

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 43c29295f477e..116d67ab93dcd 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -5263,10 +5263,9 @@ static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len)
 {
 	struct btrfs_root *root = sctx->send_root;
 	struct btrfs_fs_info *fs_info = root->fs_info;
-	struct folio *folio;
-	pgoff_t index = offset >> PAGE_SHIFT;
-	pgoff_t last_index;
-	unsigned pg_offset = offset_in_page(offset);
+	u64 cur = offset;
+	const u64 end = offset + len;
+	const pgoff_t last_index = ((end - 1) >> PAGE_SHIFT);
 	struct address_space *mapping = sctx->cur_inode->i_mapping;
 	int ret;
 
@@ -5274,11 +5273,11 @@ static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len)
 	if (ret)
 		return ret;
 
-	last_index = (offset + len - 1) >> PAGE_SHIFT;
-
-	while (index <= last_index) {
-		unsigned cur_len = min_t(unsigned, len,
-					 PAGE_SIZE - pg_offset);
+	while (cur < end) {
+		pgoff_t index = (cur >> PAGE_SHIFT);
+		unsigned int cur_len;
+		unsigned int pg_offset;
+		struct folio *folio;
 
 		folio = filemap_lock_folio(mapping, index);
 		if (IS_ERR(folio)) {
@@ -5292,8 +5291,8 @@ static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len)
 				break;
 			}
 		}
-
-		WARN_ON(folio_order(folio));
+		pg_offset = offset_in_folio(folio, cur);
+		cur_len = min_t(unsigned int, end - cur, folio_size(folio) - pg_offset);
 
 		if (folio_test_readahead(folio))
 			page_cache_async_readahead(mapping, &sctx->ra, NULL, folio,
@@ -5323,9 +5322,7 @@ static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len)
 				  pg_offset, cur_len);
 		folio_unlock(folio);
 		folio_put(folio);
-		index++;
-		pg_offset = 0;
-		len -= cur_len;
+		cur += cur_len;
 		sctx->send_size += cur_len;
 	}