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Message-Id: <20230202204428.3267832-3-willy@infradead.org> Date: Thu, 2 Feb 2023 20:44:24 +0000 From: "Matthew Wilcox (Oracle)" <willy@...radead.org> To: linux-fsdevel@...r.kernel.org Cc: "Matthew Wilcox (Oracle)" <willy@...radead.org>, linux-afs@...ts.infradead.org, linux-btrfs@...r.kernel.org, linux-ext4@...r.kernel.org, linux-mm@...ck.org, Hugh Dickins <hughd@...gle.com>, linux-kernel@...r.kernel.org, fstests@...r.kernel.org Subject: [PATCH 2/5] ext4: Zero bytes after 'oldsize' if we're expanding the file 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@...radead.org> --- 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
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