summaryrefslogtreecommitdiff
path: root/fs/ext4
diff options
context:
space:
mode:
authorJan Kara <jack@suse.cz>2017-01-27 22:35:38 +0300
committerTheodore Ts'o <tytso@mit.edu>2017-01-27 22:35:38 +0300
commit3b136499e906460919f0d21a49db1aaccf0ae963 (patch)
tree9da71e2dcd4f4d90b21ed5ec7a4c9cb44c0b0194 /fs/ext4
parentcd648b8a8fd5071d232242d5ee7ee3c0815776af (diff)
downloadlinux-3b136499e906460919f0d21a49db1aaccf0ae963.tar.xz
ext4: fix data corruption in data=journal mode
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> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/inode.c23
1 files changed, 13 insertions, 10 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 1e2c881f102d..918d351d5b94 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1385,7 +1385,9 @@ errout:
* 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);
}