From: Amir Goldstein amir73il@gmail.com
[ Upstream commit ffa5723c6d259b3191f851a50a98d0352b345b39 ]
Create some ovl_i_* helpers to get real path from ovl inode. Instead of just stashing struct inode for the lower layer we stash struct path for the lower layer. The helpers allow to retrieve a struct path for the relevant upper or lower layer. This will be used when retrieving information based on struct inode when copying up inode attributes from upper or lower inodes to ovl inodes and when checking permissions in ovl_permission() in following patches. This is needed to support idmapped base layers with overlay.
Cc: linux-unionfs@vger.kernel.org Tested-by: Giuseppe Scrivano gscrivan@redhat.com Reviewed-by: Christian Brauner (Microsoft) brauner@kernel.org Signed-off-by: Amir Goldstein amir73il@gmail.com Signed-off-by: Christian Brauner (Microsoft) brauner@kernel.org Signed-off-by: Miklos Szeredi mszeredi@redhat.com Stable-dep-of: b306e90ffabd ("ovl: remove privs in ovl_copyfile()") Signed-off-by: Sasha Levin sashal@kernel.org --- fs/overlayfs/inode.c | 11 +++++++---- fs/overlayfs/overlayfs.h | 2 ++ fs/overlayfs/ovl_entry.h | 2 +- fs/overlayfs/super.c | 5 +++-- fs/overlayfs/util.c | 15 ++++++++++++++- 5 files changed, 27 insertions(+), 8 deletions(-)
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 1f36158c7dbe..06479bc88b7e 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -777,13 +777,16 @@ void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip, unsigned long ino, int fsid) { struct inode *realinode; + struct ovl_inode *oi = OVL_I(inode);
if (oip->upperdentry) - OVL_I(inode)->__upperdentry = oip->upperdentry; - if (oip->lowerpath && oip->lowerpath->dentry) - OVL_I(inode)->lower = igrab(d_inode(oip->lowerpath->dentry)); + oi->__upperdentry = oip->upperdentry; + if (oip->lowerpath && oip->lowerpath->dentry) { + oi->lowerpath.dentry = dget(oip->lowerpath->dentry); + oi->lowerpath.layer = oip->lowerpath->layer; + } if (oip->lowerdata) - OVL_I(inode)->lowerdata = igrab(d_inode(oip->lowerdata)); + oi->lowerdata = igrab(d_inode(oip->lowerdata));
realinode = ovl_inode_real(inode); ovl_copyattr(realinode, inode); diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 2cd5741c873b..27f221962665 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -293,10 +293,12 @@ 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); enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); struct dentry *ovl_dentry_upper(struct dentry *dentry); struct dentry *ovl_dentry_lower(struct dentry *dentry); struct dentry *ovl_dentry_lowerdata(struct dentry *dentry); +const struct ovl_layer *ovl_i_layer_lower(struct inode *inode); const struct ovl_layer *ovl_layer_lower(struct dentry *dentry); struct dentry *ovl_dentry_real(struct dentry *dentry); struct dentry *ovl_i_dentry_upper(struct inode *inode); diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h index 63efee554f69..b2d64f3c974b 100644 --- a/fs/overlayfs/ovl_entry.h +++ b/fs/overlayfs/ovl_entry.h @@ -129,7 +129,7 @@ struct ovl_inode { unsigned long flags; struct inode vfs_inode; struct dentry *__upperdentry; - struct inode *lower; + struct ovl_path lowerpath;
/* synchronize copy up and more */ struct mutex lock; diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 9837aaf9caf1..e2ed38c5f721 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -184,7 +184,8 @@ static struct inode *ovl_alloc_inode(struct super_block *sb) oi->version = 0; oi->flags = 0; oi->__upperdentry = NULL; - oi->lower = NULL; + oi->lowerpath.dentry = NULL; + oi->lowerpath.layer = NULL; oi->lowerdata = NULL; mutex_init(&oi->lock);
@@ -205,7 +206,7 @@ static void ovl_destroy_inode(struct inode *inode) struct ovl_inode *oi = OVL_I(inode);
dput(oi->__upperdentry); - iput(oi->lower); + dput(oi->lowerpath.dentry); if (S_ISDIR(inode->i_mode)) ovl_dir_cache_free(inode); else diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index f48284a2a896..2567918dc684 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -236,6 +236,17 @@ 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) +{ + path->dentry = ovl_i_dentry_upper(inode); + if (!path->dentry) { + path->dentry = OVL_I(inode)->lowerpath.dentry; + path->mnt = OVL_I(inode)->lowerpath.layer->mnt; + } else { + path->mnt = ovl_upper_mnt(OVL_FS(inode->i_sb)); + } +} + struct inode *ovl_inode_upper(struct inode *inode) { struct dentry *upperdentry = ovl_i_dentry_upper(inode); @@ -245,7 +256,9 @@ struct inode *ovl_inode_upper(struct inode *inode)
struct inode *ovl_inode_lower(struct inode *inode) { - return OVL_I(inode)->lower; + struct dentry *lowerdentry = OVL_I(inode)->lowerpath.dentry; + + return lowerdentry ? d_inode(lowerdentry) : NULL; }
struct inode *ovl_inode_real(struct inode *inode)