From: Zhihao Cheng chengzhihao1@huawei.com
[ Upstream commit b2dd05f107b11966e26fe52a313b418364cf497b ]
Let helper ovl_i_path_real() return the realinode to prepare for checking non-null realinode in RCU walking path.
[msz] Use d_inode_rcu() since we are depending on the consitency between dentry and inode being non-NULL in an RCU setting.
There are some changes from upstream commit: 1. Context conflicts caused by 73db6a063c785bc ("ovl: port to vfs{g,u}id_t and associated helpers") is handled.
Signed-off-by: Zhihao Cheng chengzhihao1@huawei.com Signed-off-by: Amir Goldstein amir73il@gmail.com Fixes: ffa5723c6d25 ("ovl: store lower path in ovl_inode") Cc: stable@vger.kernel.org # v5.19 Signed-off-by: Miklos Szeredi mszeredi@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/overlayfs/overlayfs.h | 2 +- fs/overlayfs/util.c | 7 ++++--- 2 files changed, 5 insertions(+), 4 deletions(-)
--- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -369,7 +369,7 @@ enum ovl_path_type ovl_path_type(struct void ovl_path_upper(struct dentry *dentry, struct path *path); void ovl_path_lower(struct dentry *dentry, struct path *path); void ovl_path_lowerdata(struct dentry *dentry, struct path *path); -void ovl_i_path_real(struct inode *inode, struct path *path); +struct inode *ovl_i_path_real(struct inode *inode, struct path *path); enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path); struct dentry *ovl_dentry_upper(struct dentry *dentry); --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -266,7 +266,7 @@ struct dentry *ovl_i_dentry_upper(struct return ovl_upperdentry_dereference(OVL_I(inode)); }
-void ovl_i_path_real(struct inode *inode, struct path *path) +struct inode *ovl_i_path_real(struct inode *inode, struct path *path) { path->dentry = ovl_i_dentry_upper(inode); if (!path->dentry) { @@ -275,6 +275,8 @@ void ovl_i_path_real(struct inode *inode } else { path->mnt = ovl_upper_mnt(OVL_FS(inode->i_sb)); } + + return path->dentry ? d_inode_rcu(path->dentry) : NULL; }
struct inode *ovl_inode_upper(struct inode *inode) @@ -1121,8 +1123,7 @@ void ovl_copyattr(struct inode *inode) struct inode *realinode; struct user_namespace *real_mnt_userns;
- ovl_i_path_real(inode, &realpath); - realinode = d_inode(realpath.dentry); + realinode = ovl_i_path_real(inode, &realpath); real_mnt_userns = mnt_user_ns(realpath.mnt);
inode->i_uid = i_uid_into_mnt(real_mnt_userns, realinode);