From b419470930fbb75deb48706a23aa3a8878e8b85c Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Wed, 8 Nov 2017 09:39:46 +0200 Subject: [PATCH] ovl: fix failure to fsync lower dir MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit d796e77f1dd541fe34481af2eee6454688d13982 upstream. As a writable mount, it is not expected for overlayfs to return EINVAL/EROFS for fsync, even if dir/file is not changed. This commit fixes the case of fsync of directory, which is easier to address, because overlayfs already implements fsync file operation for directories. The problem reported by Raphael is that new PostgreSQL 10.0 with a database in overlayfs where lower layer in squashfs fails to start. The failure is due to fsync error, when PostgreSQL does fsync on all existing db directories on startup and a specific directory exists lower layer with no changes. Reported-by: Raphael Hertzog Signed-off-by: Amir Goldstein Tested-by: Raphaël Hertzog Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman [sw0312.kim: cherry-pick linux-4.4.y commit 3b0104f9e21a to fix smack deny issue on overlayfs] Signed-off-by: Seung-Woo Kim Change-Id: Ieda49c00978f4f26f062a72e83d986d5f97d7f1f --- fs/overlayfs/readdir.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index adcb1398c481..299a6e1d6b77 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -441,10 +441,14 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end, struct dentry *dentry = file->f_path.dentry; struct file *realfile = od->realfile; + /* Nothing to sync for lower */ + if (!OVL_TYPE_UPPER(ovl_path_type(dentry))) + return 0; + /* * Need to check if we started out being a lower dir, but got copied up */ - if (!od->is_upper && OVL_TYPE_UPPER(ovl_path_type(dentry))) { + if (!od->is_upper) { struct inode *inode = file_inode(file); realfile = lockless_dereference(od->upperfile); -- 2.34.1