X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=fs%2Fext4%2Fpage-io.c;h=b12a4427aedc41f71bbbf697cbc61e17e30963cf;hb=ebb1d078e4a8f9f2e9d1c822823671d5131fc42f;hp=4acf1f78881b6c4c61aa10377a62ea4368106593;hpb=3d0d8b9155b2a60e3d2498e7d928051043d2d546;p=firefly-linux-kernel-4.4.55.git

diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 4acf1f78881b..b12a4427aedc 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -383,6 +383,17 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
 	set_page_writeback(page);
 	ClearPageError(page);
 
+	/*
+	 * Comments copied from block_write_full_page_endio:
+	 *
+	 * The page straddles i_size.  It must be zeroed out on each and every
+	 * writepage invocation because it may be mmapped.  "A file is mapped
+	 * in multiples of the page size.  For a file that is not a multiple of
+	 * the page size, the remaining memory is zeroed when mapped, and
+	 * writes to that region are not written out to the file."
+	 */
+	if (len < PAGE_CACHE_SIZE)
+		zero_user_segment(page, len, PAGE_CACHE_SIZE);
 	/*
 	 * In the first loop we prepare and mark buffers to submit. We have to
 	 * mark all buffers in the page before submitting so that
@@ -394,19 +405,6 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
 	do {
 		block_start = bh_offset(bh);
 		if (block_start >= len) {
-			/*
-			 * Comments copied from block_write_full_page_endio:
-			 *
-			 * The page straddles i_size.  It must be zeroed out on
-			 * each and every writepage invocation because it may
-			 * be mmapped.  "A file is mapped in multiples of the
-			 * page size.  For a file that is not a multiple of
-			 * the  page size, the remaining memory is zeroed when
-			 * mapped, and writes to that region are not written
-			 * out to the file."
-			 */
-			zero_user_segment(page, block_start,
-					  block_start + blocksize);
 			clear_buffer_dirty(bh);
 			set_buffer_uptodate(bh);
 			continue;