From b2dd05f107b11966e26fe52a313b418364cf497b Mon Sep 17 00:00:00 2001 From: Zhihao Cheng Date: Tue, 16 May 2023 22:16:17 +0800 Subject: [PATCH] ovl: let helper ovl_i_path_real() return the realinode 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. Signed-off-by: Zhihao Cheng Signed-off-by: Amir Goldstein Fixes: ffa5723c6d25 ("ovl: store lower path in ovl_inode") Cc: # v5.19 Signed-off-by: Miklos Szeredi --- fs/overlayfs/overlayfs.h | 2 +- fs/overlayfs/util.c | 7 ++++--- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 4d0b278..7398de3 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -382,7 +382,7 @@ enum ovl_path_type ovl_path_type(struct dentry *dentry); 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); diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index 923d66d..5a6f34c 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -250,7 +250,7 @@ struct dentry *ovl_i_dentry_upper(struct inode *inode) 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) { @@ -259,6 +259,8 @@ void ovl_i_path_real(struct inode *inode, struct path *path) } 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) @@ -1105,8 +1107,7 @@ void ovl_copyattr(struct inode *inode) vfsuid_t vfsuid; vfsgid_t vfsgid; - ovl_i_path_real(inode, &realpath); - realinode = d_inode(realpath.dentry); + realinode = ovl_i_path_real(inode, &realpath); real_idmap = mnt_idmap(realpath.mnt); vfsuid = i_uid_into_vfsuid(real_idmap, realinode); -- 2.7.4