From 24b33ee104ecd5a4e1e71412f8966199d6a0bf02 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Tue, 26 Sep 2017 07:55:26 +0300 Subject: [PATCH] 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/copy_up.c | 6 +----- fs/overlayfs/overlayfs.h | 1 + fs/overlayfs/util.c | 24 ++++++++++++++++++++---- 3 files changed, 22 insertions(+), 9 deletions(-) diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index 503c924..103e62d 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -536,11 +536,7 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) { int err; struct ovl_fs *ofs = c->dentry->d_sb->s_fs_info; - bool indexed = false; - - if (ovl_indexdir(c->dentry->d_sb) && !S_ISDIR(c->stat.mode) && - c->stat.nlink > 1) - indexed = true; + bool indexed = ovl_need_index(c->dentry); if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || indexed) c->origin = true; diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 25794a3..d7e6528 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -241,6 +241,7 @@ void ovl_clear_flag(unsigned long flag, struct inode *inode); bool ovl_test_flag(unsigned long flag, struct inode *inode); bool ovl_inuse_trylock(struct dentry *dentry); void ovl_inuse_unlock(struct dentry *dentry); +bool ovl_need_index(struct dentry *dentry); int ovl_nlink_start(struct dentry *dentry, bool *locked); void ovl_nlink_end(struct dentry *dentry, bool locked); int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir); diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index ae81d87..55ab991 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; -- 2.7.4