Currently we capture a NULL data exposure problem after a crash or
poweroff when append writing a file in the data=ordered mode. The
problem is that we were not add inode to the transaction's order data
list when updating i_disksize without new block allocation no matter
the delay allocated block feature is enabled or not.
write jbd2 writeback
append write in allocated block
mark buffer dirty
update i_disksize
mark inode dirty
commit transaction
write inode
(data exposure after a crash)
write dirty buffer
It's fine in the case of new block allocation because we do this job in
ext4_map_blocks(). To fix this problem, this patch add inode to current
transaction's order data list after new data is copied and needing
update i_disksize in the case of no block allocation.
Fixes: 06bd3c36a733ac ("ext4: fix data exposure after a crash")
Fixes: f3b59291a69d0b ("ext4: remove calls to ext4_jbd2_file_inode() from delalloc write path")
Signed-off-by: zhangyi (F) <yi.zhang@xxxxxxxxxx>
---
fs/ext4/inode.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index b32a57b..5cfa066 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1419,6 +1419,16 @@ static int ext4_write_end(struct file *file,
if (i_size_changed || inline_data)
ext4_mark_inode_dirty(handle, inode);
+ /*
+ * Updating i_disksize when extending file without block
+ * allocation, the newly written data where should be visible
+ * after transaction commit must be on transaction's ordered
+ * data list.
+ */
+ if (copied && (i_size_changed & 0x2) &&
+ ext4_should_order_data(inode))
+ ext4_jbd2_inode_add_write(handle, inode);
+
if (pos + len > inode->i_size && ext4_can_truncate(inode))
/* if we have allocated more blocks and copied
* less. We will have blocks allocated outside
@@ -3185,6 +3195,15 @@ static int ext4_da_write_end(struct file *file,
* bu greater than i_disksize.(hint delalloc)
*/
ext4_mark_inode_dirty(handle, inode);
+
+ /*
+ * Updating i_disksize when extending file without
+ * block allocation, the newly written data where
+ * should be visible after transaction commit must
+ * be on transaction's ordered data list.
+ */
+ if (ext4_should_order_data(inode))
+ ext4_jbd2_inode_add_write(handle, inode);
}
}
--
2.7.4
