From de30dfd629e2e07e2e9d672b2931bcd60f9a34c0 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Wed, 18 Jul 2018 15:44:42 +0200 Subject: [PATCH] ovl: add ovl_fsync() Implement stacked fsync(). Don't sync if lower (noticed by Amir Goldstein). Signed-off-by: Miklos Szeredi --- fs/overlayfs/file.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 53d95c9d976a..8adddee93418 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -233,10 +233,33 @@ out_unlock: return ret; } +static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync) +{ + struct fd real; + const struct cred *old_cred; + int ret; + + ret = ovl_real_fdget(file, &real); + if (ret) + return ret; + + /* Don't sync lower file for fear of receiving EROFS error */ + if (file_inode(real.file) == ovl_inode_upper(file_inode(file))) { + old_cred = ovl_override_creds(file_inode(file)->i_sb); + ret = vfs_fsync_range(real.file, start, end, datasync); + revert_creds(old_cred); + } + + fdput(real); + + return ret; +} + const struct file_operations ovl_file_operations = { .open = ovl_open, .release = ovl_release, .llseek = ovl_llseek, .read_iter = ovl_read_iter, .write_iter = ovl_write_iter, + .fsync = ovl_fsync, }; -- 2.30.2