9p: saner ->write_end() on failing copy into non-uptodate page
If we had a short copy into an uptodate page, there's no reason
whatsoever to zero anything; OTOH, if that page had _not_ been
uptodate, we must have been trying to overwrite it completely
and got a short copy. In that case, overwriting the end with
zeroes, marking uptodate and sending to server is just plain
wrong. Just unlock, keep it non-uptodate and return 0.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 6181ad7..ff8ece8 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -309,18 +309,10 @@
p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
- if (unlikely(copied < len)) {
- /*
- * zero out the rest of the area
- */
- unsigned from = pos & (PAGE_SIZE - 1);
-
- zero_user(page, from + copied, len - copied);
- flush_dcache_page(page);
+ if (unlikely(copied < len && !PageUptodate(page))) {
+ copied = 0;
+ goto out;
}
-
- 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.
@@ -330,6 +322,7 @@
i_size_write(inode, last_pos);
}
set_page_dirty(page);
+out:
unlock_page(page);
put_page(page);