simple_write_end(): don't zero in short copy into uptodate
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/libfs.c b/fs/libfs.c
index 48826d4..7604870 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -465,6 +465,8 @@
* is not called, so a filesystem that actually does store data in .write_inode
* should extend on what's done here with a call to mark_inode_dirty() in the
* case that i_size has changed.
+ *
+ * Use *ONLY* with simple_readpage()
*/
int simple_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
@@ -474,14 +476,14 @@
loff_t last_pos = pos + copied;
/* zero the stale part of the page if we did a short copy */
- if (copied < len) {
- unsigned from = pos & (PAGE_SIZE - 1);
+ if (!PageUptodate(page)) {
+ if (copied < len) {
+ unsigned from = pos & (PAGE_SIZE - 1);
- zero_user(page, from + copied, len - copied);
- }
-
- if (!PageUptodate(page))
+ zero_user(page, from + copied, len - copied);
+ }
SetPageUptodate(page);
+ }
/*
* No need to use i_size_read() here, the i_size
* cannot change under us because we hold the i_mutex.