simple_write_end(): don't zero in short copy into uptodate

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2016-08-29 22:39:56 -04:00
parent 92e50d2d42
commit 04fff6416c
1 changed files with 8 additions and 6 deletions

View File

@ -465,6 +465,8 @@ EXPORT_SYMBOL(simple_write_begin);
* 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 @@ int simple_write_end(struct file *file, struct address_space *mapping,
loff_t last_pos = pos + copied;
/* zero the stale part of the page if we did a short copy */
if (!PageUptodate(page)) {
if (copied < len) {
unsigned from = pos & (PAGE_SIZE - 1);
zero_user(page, from + copied, len - copied);
}
if (!PageUptodate(page))
SetPageUptodate(page);
}
/*
* No need to use i_size_read() here, the i_size
* cannot change under us because we hold the i_mutex.