[SRU][Zesty][PATCH 08/10] ovl: merge getattr for dir and nondir

[Daniel Axtens]

From: Miklos Szeredi <mszeredi at redhat.com>

BugLink: https://bugs.launchpad.net/bugs/1728489

Signed-off-by: Miklos Szeredi <mszeredi at redhat.com>
(backported from commit 5b712091a3a3904b0ae8311e18e6b540a070d464)
Signed-off-by: Daniel Axtens <daniel.axtens at canonical.com>

---
This patch also has no description in upstream.
---
 fs/overlayfs/dir.c       | 59 +-----------------------------------------------
 fs/overlayfs/inode.c     | 28 ++++++++++++++++++++---
 fs/overlayfs/overlayfs.h |  2 ++
 3 files changed, 28 insertions(+), 61 deletions(-)

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 94d9ee8aa837..0f57a42426ef 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -138,63 +138,6 @@ static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
 	return err;
 }
 
-static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
-			 struct kstat *stat)
-{
-	int err;
-	enum ovl_path_type type;
-	struct path realpath;
-	const struct cred *old_cred;
-
-	type = ovl_path_real(dentry, &realpath);
-	old_cred = ovl_override_creds(dentry->d_sb);
-	err = vfs_getattr(&realpath, stat);
-	if (err)
-		goto out;
-
-	/*
-	 * When all layers are on the same fs, use the copy-up-origin st_ino,
-	 * which is persistent, unique and constant across copy up.
-	 *
-	 * Otherwise the pair {real st_ino; overlay st_dev} is not unique, so
-	 * use the non persistent overlay st_ino.
-	 */
-	if (ovl_same_sb(dentry->d_sb)) {
-		if (OVL_TYPE_ORIGIN(type)) {
-			struct kstat lowerstat;
-
-			ovl_path_lower(dentry, &realpath);
-			err = vfs_getattr(&realpath, &lowerstat);
-			if (err)
-				goto out;
-
-			WARN_ON_ONCE(stat->dev != lowerstat.dev);
-			stat->ino = lowerstat.ino;
-		}
-	} else {
-		stat->ino = dentry->d_inode->i_ino;
-	}
-
-	/*
-	 * Always use the overlay st_dev for directories, so 'find -xdev' will
-	 * scan the entire overlay mount and won't cross the overlay mount
-	 * boundaries.
-	 */
-	stat->dev = dentry->d_sb->s_dev;
-
-	/*
-	 * It's probably not worth it to count subdirs to get the
-	 * correct link count.  nlink=1 seems to pacify 'find' and
-	 * other utilities.
-	 */
-	if (OVL_TYPE_MERGE(type))
-		stat->nlink = 1;
-out:
-	revert_creds(old_cred);
-
-	return err;
-}
-
 /* Common operations required to be done after creation of file on upper */
 static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
 			    struct dentry *newdentry, bool hardlink)
@@ -1096,7 +1039,7 @@ const struct inode_operations ovl_dir_inode_operations = {
 	.create		= ovl_create,
 	.mknod		= ovl_mknod,
 	.permission	= ovl_permission,
-	.getattr	= ovl_dir_getattr,
+	.getattr	= ovl_getattr,
 	.listxattr	= ovl_listxattr,
 	.get_acl	= ovl_get_acl,
 	.update_time	= ovl_update_time,
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index c9eb9193f4ef..c80109b340a4 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -56,12 +56,13 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr)
 	return err;
 }
 
-static int ovl_getattr(struct vfsmount *mnt, struct dentry *dentry,
-			 struct kstat *stat)
+int ovl_getattr(struct vfsmount *mnt, struct dentry *dentry,
+		struct kstat *stat)
 {
 	enum ovl_path_type type;
 	struct path realpath;
 	const struct cred *old_cred;
+	bool is_dir = S_ISDIR(dentry->d_inode->i_mode);
 	int err;
 
 	type = ovl_path_real(dentry, &realpath);
@@ -95,11 +96,32 @@ static int ovl_getattr(struct vfsmount *mnt, struct dentry *dentry,
 			 * upper files, so we cannot use the lower origin st_ino
 			 * for those different files, even for the same fs case.
 			 */
-			if (lowerstat.nlink == 1)
+			if (is_dir || lowerstat.nlink == 1)
 				stat->ino = lowerstat.ino;
 		}
 		stat->dev = dentry->d_sb->s_dev;
+	} else if (is_dir) {
+		/*
+		 * If not all layers are on the same fs the pair {real st_ino;
+		 * overlay st_dev} is not unique, so use the non persistent
+		 * overlay st_ino.
+		 *
+		 * Always use the overlay st_dev for directories, so 'find
+		 * -xdev' will scan the entire overlay mount and won't cross the
+		 * overlay mount boundaries.
+		 */
+		stat->dev = dentry->d_sb->s_dev;
+		stat->ino = dentry->d_inode->i_ino;
 	}
+
+	/*
+	 * It's probably not worth it to count subdirs to get the
+	 * correct link count.  nlink=1 seems to pacify 'find' and
+	 * other utilities.
+	 */
+	if (is_dir && OVL_TYPE_MERGE(type))
+		stat->nlink = 1;
+
 out:
 	revert_creds(old_cred);
 
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 883a77b0636c..929165460f28 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -237,6 +237,8 @@ void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
 
 /* inode.c */
 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
+int ovl_getattr(struct vfsmount *mnt, struct dentry *dentry,
+		struct kstat *stat);
 int ovl_permission(struct inode *inode, int mask);
 int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
 		  size_t size, int flags);
-- 
2.11.0