ext4: avoid potential hang in mpage_submit_io() when blocksize < pagesize
If there is an unwritten but clean buffer in a page and there is a
dirty buffer after the buffer, then mpage_submit_io does not write the
dirty buffer out. As a result, da_writepages loops forever.
This patch fixes the problem by checking dirty flag.
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index b5edc6e..cf20e1f 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1339,8 +1339,11 @@
clear_buffer_unwritten(bh);
}
- /* skip page if block allocation undone */
- if (buffer_delay(bh) || buffer_unwritten(bh))
+ /*
+ * skip page if block allocation undone and
+ * block is dirty
+ */
+ if (ext4_bh_delay_or_unwritten(NULL, bh))
skip_page = 1;
bh = bh->b_this_page;
block_start += bh->b_size;