1 files changed, 37 insertions, 3 deletions

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 86e36c630f09..8059ece82468 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -28,6 +28,7 @@
 #include <linux/mm.h>
 #include <linux/pagemap.h>
 #include <linux/gfp.h>
+#include <linux/rmap.h>
 #include <linux/swap.h>
 #include <linux/compaction.h>
 
@@ -280,6 +281,37 @@ nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 }
 EXPORT_SYMBOL_GPL(nfs_file_fsync);
 
+void nfs_truncate_last_folio(struct address_space *mapping, loff_t from,
+			     loff_t to)
+{
+	struct folio *folio;
+
+	if (from >= to)
+		return;
+
+	folio = filemap_lock_folio(mapping, from >> PAGE_SHIFT);
+	if (IS_ERR(folio))
+		return;
+
+	if (folio_mkclean(folio))
+		folio_mark_dirty(folio);
+
+	if (folio_test_uptodate(folio)) {
+		loff_t fpos = folio_pos(folio);
+		size_t offset = from - fpos;
+		size_t end = folio_size(folio);
+
+		if (to - fpos < end)
+			end = to - fpos;
+		folio_zero_segment(folio, offset, end);
+		trace_nfs_size_truncate_folio(mapping->host, to);
+	}
+
+	folio_unlock(folio);
+	folio_put(folio);
+}
+EXPORT_SYMBOL_GPL(nfs_truncate_last_folio);
+
 /*
  * Decide whether a read/modify/write cycle may be more efficient
  * then a modify/write/read cycle when writing to a page in the
@@ -356,6 +388,7 @@ static int nfs_write_begin(const struct kiocb *iocb,
 
 	dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n",
 		file, mapping->host->i_ino, len, (long long) pos);
+	nfs_truncate_last_folio(mapping, i_size_read(mapping->host), pos);
 
 	fgp |= fgf_set_order(len);
 start:
@@ -442,10 +475,11 @@ static void nfs_invalidate_folio(struct folio *folio, size_t offset,
 	dfprintk(PAGECACHE, "NFS: invalidate_folio(%lu, %zu, %zu)\n",
 		 folio->index, offset, length);
 
-	if (offset != 0 || length < folio_size(folio))
-		return;
 	/* Cancel any unstarted writes on this page */
-	nfs_wb_folio_cancel(inode, folio);
+	if (offset != 0 || length < folio_size(folio))
+		nfs_wb_folio(inode, folio);
+	else
+		nfs_wb_folio_cancel(inode, folio);
 	folio_wait_private_2(folio); /* [DEPRECATED] */
 	trace_nfs_invalidate_folio(inode, folio_pos(folio) + offset, length);
 }