From 24b33ee104ecd5a4e1e71412f8966199d6a0bf02 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Tue, 26 Sep 2017 07:55:26 +0300 Subject: ovl: create ovl_need_index() helper The helper determines which lower file needs to be indexed on copy up and before nlink changes. For index=on, the helper evaluates to true for lower hardlinks. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi --- fs/overlayfs/util.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) (limited to 'fs/overlayfs/util.c') diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index ae81d878248e..55ab99131a72 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -463,6 +463,23 @@ void ovl_inuse_unlock(struct dentry *dentry) } } +/* + * Does this overlay dentry need to be indexed on copy up? + */ +bool ovl_need_index(struct dentry *dentry) +{ + struct dentry *lower = ovl_dentry_lower(dentry); + + if (!lower || !ovl_indexdir(dentry->d_sb)) + return false; + + /* Index only lower hardlinks on copy up */ + if (!d_is_dir(lower) && d_inode(lower)->i_nlink > 1) + return true; + + return false; +} + /* Caller must hold OVL_I(inode)->lock */ static void ovl_cleanup_index(struct dentry *dentry) { @@ -533,11 +550,11 @@ int ovl_nlink_start(struct dentry *dentry, bool *locked) /* * With inodes index is enabled, we store the union overlay nlink - * in an xattr on the index inode. When whiting out lower hardlinks + * in an xattr on the index inode. When whiting out an indexed lower, * we need to decrement the overlay persistent nlink, but before the * first copy up, we have no upper index inode to store the xattr. * - * As a workaround, before whiteout/rename over of a lower hardlink, + * As a workaround, before whiteout/rename over an indexed lower, * copy up to create the upper index. Creating the upper index will * initialize the overlay nlink, so it could be dropped if unlink * or rename succeeds. @@ -545,8 +562,7 @@ int ovl_nlink_start(struct dentry *dentry, bool *locked) * TODO: implement metadata only index copy up when called with * ovl_copy_up_flags(dentry, O_PATH). */ - if (ovl_indexdir(dentry->d_sb) && !ovl_dentry_has_upper_alias(dentry) && - d_inode(ovl_dentry_lower(dentry))->i_nlink > 1) { + if (ovl_need_index(dentry) && !ovl_dentry_has_upper_alias(dentry)) { err = ovl_copy_up(dentry); if (err) return err; -- cgit v1.2.2