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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pNgRb-00Di7j-LB; Thu, 02 Feb 2023 20:44:31 +0000 From: "Matthew Wilcox (Oracle)" To: linux-fsdevel@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" , linux-afs@lists.infradead.org, linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-mm@kvack.org, Hugh Dickins , linux-kernel@vger.kernel.org, fstests@vger.kernel.org Subject: [PATCH 5/5] btrfs: Zero bytes after 'oldsize' if we're expanding the file Date: Thu, 2 Feb 2023 20:44:27 +0000 Message-Id: <20230202204428.3267832-6-willy@infradead.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230202204428.3267832-1-willy@infradead.org> References: <20230202204428.3267832-1-willy@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: CA5E64001A X-Rspamd-Server: rspam01 X-Stat-Signature: 3isoab3yptweu6znz34iwe3if3t1uw77 X-HE-Tag: 1675370676-714794 X-HE-Meta: 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 RavfKnj0 PFwVPqKYCAhYYJdJcjr3+TvJWlVA2dByNNtTLhaB6ytuvj8Fls3PD0sBH2XgVlrODNgoDMzbjq1BbCE5oYGxQznBiRmSht5B2b33dej8cgr8j8GS+uJqN5W8DvLrYhksQ+lJeNiTUERhBJ5upCPIltW/JuS7jAkJD/Mqpqh6ubg58au9FI+UCqbflxXaaU71uGVnH X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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) --- fs/btrfs/inode.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 98a800b8bd43..b61ec4bb9cf0 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -5234,6 +5234,7 @@ static int btrfs_setsize(struct inode *inode, struct iattr *attr) i_size_write(inode, newsize); btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0); pagecache_isize_extended(inode, oldsize, newsize); + truncate_pagecache(inode, oldsize); ret = btrfs_update_inode(trans, root, BTRFS_I(inode)); btrfs_drew_write_unlock(&root->snapshot_lock); btrfs_end_transaction(trans); -- 2.35.1