POSIX requires that "If the file size is increased, the extended area
shall appear as if it were zero-filled". It is possible to use mmap to
write past EOF and that data will become visible instead of zeroes.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
fs/ext4/inode.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9d9f414f99fe..14e3fa99f733 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5604,6 +5604,7 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
if (!shrink) {
pagecache_isize_extended(inode, oldsize,
inode->i_size);
+ truncate_pagecache(inode, oldsize);
} else if (ext4_should_journal_data(inode)) {
ext4_wait_for_tail_page_commit(inode);
}
--
2.35.1
