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From: Christian Brauner <brauner@kernel.org>
To: Amir Goldstein <amir73il@gmail.com>,
	Miklos Szeredi <mszeredi@redhat.com>
Cc: "Christoph Hellwig" <hch@lst.de>,
	linux-unionfs@vger.kernel.org, "Aleksa Sarai" <cyphar@cyphar.com>,
	"Giuseppe Scrivano" <gscrivan@redhat.com>,
	"Rodrigo Campos Catelin" <rodrigo@sdfg.com.ar>,
	"Seth Forshee" <sforshee@digitalocean.com>,
	"Luca Bocassi" <luca.boccassi@microsoft.com>,
	"Lennart Poettering" <mzxreary@0pointer.de>,
	"Stéphane Graber" <stgraber@ubuntu.com>,
	"Christian Brauner" <brauner@kernel.org>
Subject: [PATCH v3 14/19] ovl: store lower path in ovl_inode
Date: Thu, 31 Mar 2022 13:23:12 +0200	[thread overview]
Message-ID: <20220331112318.1377494-15-brauner@kernel.org> (raw)
In-Reply-To: <20220331112318.1377494-1-brauner@kernel.org>

From: Amir Goldstein <amir73il@gmail.com>

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>
---
/* v2 */
unchanged

/* v3 */
unchanged
---
 fs/overlayfs/inode.c     | 11 +++++---
 fs/overlayfs/overlayfs.h |  6 ++++
 fs/overlayfs/ovl_entry.h |  2 +-
 fs/overlayfs/super.c     |  5 ++--
 fs/overlayfs/util.c      | 61 ++++++++++++++++++++++++++++++++++------
 5 files changed, 69 insertions(+), 16 deletions(-)

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index f18b02b9dd53..e28b7ed755b3 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -779,13 +779,16 @@ 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 347096a3d4a3..6bae54d2ba78 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -361,18 +361,24 @@ bool ovl_dentry_remote(struct dentry *dentry);
 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry,
 			     unsigned int mask);
 bool ovl_dentry_weird(struct dentry *dentry);
+enum ovl_path_type ovl_i_path_type(struct inode *inode, bool is_dir,
+				   int numlower);
 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);
+enum ovl_path_type 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);
 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_real(struct inode *inode);
 struct dentry *ovl_i_dentry_upper(struct inode *inode);
+struct dentry *ovl_i_dentry_lower(struct inode *inode);
 struct inode *ovl_inode_upper(struct inode *inode);
 struct inode *ovl_inode_lower(struct inode *inode);
 struct inode *ovl_inode_lowerdata(struct inode *inode);
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 22ce60426de2..79b612cfbe52 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -134,7 +134,7 @@ 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 1ed230c7baf1..9a656a24f7b1 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 3065393d143e..7dd9901c9d17 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -125,31 +125,37 @@ bool ovl_dentry_weird(struct dentry *dentry)
 				  DCACHE_OP_COMPARE);
 }
 
-enum ovl_path_type ovl_path_type(struct dentry *dentry)
+enum ovl_path_type ovl_i_path_type(struct inode *inode, bool is_dir,
+				   int numlower)
 {
-	struct ovl_entry *oe = dentry->d_fsdata;
 	enum ovl_path_type type = 0;
 
-	if (ovl_dentry_upper(dentry)) {
+	if (ovl_i_dentry_upper(inode)) {
 		type = __OVL_PATH_UPPER;
 
 		/*
 		 * Non-dir dentry can hold lower dentry of its copy up origin.
 		 */
-		if (oe->numlower) {
-			if (ovl_test_flag(OVL_CONST_INO, d_inode(dentry)))
+		if (numlower) {
+			if (ovl_test_flag(OVL_CONST_INO, inode))
 				type |= __OVL_PATH_ORIGIN;
-			if (d_is_dir(dentry) ||
-			    !ovl_has_upperdata(d_inode(dentry)))
+			if (is_dir || !ovl_has_upperdata(inode))
 				type |= __OVL_PATH_MERGE;
 		}
 	} else {
-		if (oe->numlower > 1)
+		if (numlower > 1)
 			type |= __OVL_PATH_MERGE;
 	}
 	return type;
 }
 
+enum ovl_path_type ovl_path_type(struct dentry *dentry)
+{
+	struct ovl_entry *oe = dentry->d_fsdata;
+
+	return ovl_i_path_type(d_inode(dentry), d_is_dir(dentry), oe->numlower);
+}
+
 void ovl_path_upper(struct dentry *dentry, struct path *path)
 {
 	struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
@@ -250,6 +256,41 @@ struct dentry *ovl_i_dentry_upper(struct inode *inode)
 	return ovl_upperdentry_dereference(OVL_I(inode));
 }
 
+struct dentry *ovl_i_dentry_lower(struct inode *inode)
+{
+	return OVL_I(inode)->lowerpath.dentry;
+}
+
+struct dentry *ovl_i_dentry_real(struct inode *inode)
+{
+	return ovl_i_dentry_upper(inode) ?: ovl_i_dentry_lower(inode);
+}
+
+const struct ovl_layer *ovl_i_layer_lower(struct inode *inode)
+{
+	return OVL_I(inode)->lowerpath.layer;
+}
+
+enum ovl_path_type ovl_i_path_real(struct inode *inode, struct path *path)
+{
+	struct dentry *lowerdentry = ovl_i_dentry_lower(inode);
+	/* Will not set the __OVL_PATH_MERGE bit for merge lowers dir */
+	enum ovl_path_type type = ovl_i_path_type(inode, S_ISDIR(inode->i_mode),
+						  !!lowerdentry);
+
+	if (OVL_TYPE_UPPER(type)) {
+		path->dentry = ovl_i_dentry_upper(inode);
+		path->mnt = ovl_upper_mnt(OVL_FS(inode->i_sb));
+	} else if (lowerdentry) {
+		path->dentry = lowerdentry;
+		path->mnt = ovl_i_layer_lower(inode)->mnt;
+	} else {
+		*path = (struct path) { };
+	}
+
+	return type;
+}
+
 struct inode *ovl_inode_upper(struct inode *inode)
 {
 	struct dentry *upperdentry = ovl_i_dentry_upper(inode);
@@ -259,7 +300,9 @@ 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_dentry_lower(inode);
+
+	return lowerdentry ? d_inode(lowerdentry) : NULL;
 }
 
 struct inode *ovl_inode_real(struct inode *inode)
-- 
2.32.0


  parent reply	other threads:[~2022-03-31 11:24 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-31 11:22 [PATCH v3 00/19] overlay: support idmapped layers Christian Brauner
2022-03-31 11:22 ` [PATCH v3 01/19] fs: add two trivial lookup helpers Christian Brauner
2022-03-31 11:23 ` [PATCH v3 02/19] exportfs: support idmapped mounts Christian Brauner
2022-03-31 11:23 ` [PATCH v3 03/19] ovl: use wrappers to all vfs_*xattr() calls Christian Brauner
2022-03-31 11:23 ` [PATCH v3 04/19] ovl: pass ofs to creation operations Christian Brauner
2022-03-31 11:23 ` [PATCH v3 05/19] ovl: add ovl_upper_idmap() wrapper Christian Brauner
2022-03-31 11:23 ` [PATCH v3 06/19] ovl: handle idmappings in creation operations Christian Brauner
2022-03-31 11:23 ` [PATCH v3 07/19] ovl: pass ofs to setattr operations Christian Brauner
2022-03-31 11:23 ` [PATCH v3 08/19] ovl: pass layer mnt to ovl_open_realfile() Christian Brauner
2022-03-31 11:23 ` [PATCH v3 09/19] ovl: use ovl_do_notify_change() wrapper Christian Brauner
2022-04-01 18:49   ` Vivek Goyal
2022-04-02 12:03     ` Christian Brauner
2022-04-06 16:47       ` Vivek Goyal
2022-04-07  9:29         ` Christian Brauner
2022-03-31 11:23 ` [PATCH v3 10/19] ovl: use ovl_lookup_upper() wrapper Christian Brauner
2022-03-31 11:23 ` [PATCH v3 11/19] ovl: use ovl_path_getxattr() wrapper Christian Brauner
2022-03-31 11:23 ` [PATCH v3 12/19] ovl: handle idmappings for layer fileattrs Christian Brauner
2022-03-31 11:23 ` [PATCH v3 13/19] ovl: handle idmappings for layer lookup Christian Brauner
2022-03-31 11:23 ` Christian Brauner [this message]
2022-03-31 11:23 ` [PATCH v3 15/19] ovl: use ovl_copy_{real,upper}attr() wrappers Christian Brauner
2022-03-31 11:23 ` [PATCH v3 16/19] ovl: handle idmappings in ovl_permission() Christian Brauner
2022-03-31 11:23 ` [PATCH v3 17/19] ovl: handle idmappings in layer open helpers Christian Brauner
2022-04-01 20:11   ` Vivek Goyal
2022-03-31 11:23 ` [PATCH v3 18/19] ovl: handle idmappings in ovl_xattr_{g,s}et() Christian Brauner
2022-03-31 11:23 ` [PATCH v3 19/19] ovl: support idmapped layers Christian Brauner
2022-04-01 20:17   ` Vivek Goyal
2022-04-02  6:19     ` Christian Brauner
2022-03-31 11:23 ` [PATCH v3] common: allow to run all tests on idmapped mounts Christian Brauner
2022-03-31 11:35   ` Amir Goldstein
2022-03-31 11:41     ` Christian Brauner
2022-04-01  7:16       ` Amir Goldstein
2022-03-31 19:05 ` [PATCH v3 00/19] overlay: support idmapped layers Vivek Goyal
2022-04-01  6:54   ` Christian Brauner

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