@@ -1385,7 +1385,9 @@ static int ext4_write_end(struct file *file,
* set the buffer to be dirty, since in data=journalled mode we need
* to call ext4_handle_dirty_metadata() instead.
*/
-static void zero_new_buffers(struct page *page, unsigned from, unsigned to)
+static void ext4_journalled_zero_new_buffers(handle_t *handle,
+ struct page *page,
+ unsigned from, unsigned to)
{
unsigned int block_start = 0, block_end;
struct buffer_head *head, *bh;
@@ -1402,7 +1404,7 @@ static void zero_new_buffers(struct page *page, unsigned from, unsigned to)
size = min(to, block_end) - start;
zero_user(page, start, size);
- set_buffer_uptodate(bh);
+ write_end_fn(handle, bh);
}
clear_buffer_new(bh);
}
@@ -1434,15 +1436,16 @@ static int ext4_journalled_write_end(struct file *file,
if (ext4_has_inline_data(inode))
copied = ext4_write_inline_data_end(inode, pos, len,
copied, page);
- else {
- if (copied < len) {
- if (!PageUptodate(page))
- copied = 0;
- zero_new_buffers(page, from+copied, to);
- }
-
+ else if (unlikely(copied < len) && !PageUptodate(page)) {
+ copied = 0;
+ ext4_journalled_zero_new_buffers(handle, page, from, to);
+ } else {
+ if (unlikely(copied < len))
+ ext4_journalled_zero_new_buffers(handle, page,
+ from + copied, to);
ret = ext4_walk_page_buffers(handle, page_buffers(page), from,
- to, &partial, write_end_fn);
+ from + copied, &partial,
+ write_end_fn);
if (!partial)
SetPageUptodate(page);
}
ext4_journalled_write_end() did not propely handle all the cases when generic_perform_write() did not copy all the data into the target page and could mark buffers with uninitialized contents as uptodate and dirty leading to possible data corruption (which would be quickly fixed by generic_perform_write() retrying the write but still). Fix the problem by carefully handling the case when the page that is written to is not uptodate. CC: stable@vger.kernel.org Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Jan Kara <jack@suse.cz> --- fs/ext4/inode.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-)