[PATCH 1/2] ovl: use kernel facility for copying attributes

[PATCH 1/2] ovl: use kernel facility for copying attributes

[Quorum Laval]

Replace ovl_copyattr() by fsstack_copy_attr_all() and drop the definition of
the former.

Signed-off-by: Quorum Laval <quorum.laval@gmail.com>
---
 fs/overlayfs/dir.c       | 3 ++-
 fs/overlayfs/inode.c     | 3 ++-
 fs/overlayfs/overlayfs.h | 9 ---------
 fs/overlayfs/super.c     | 7 ++++---
 4 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 306b6c1..dbe0153 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -15,6 +15,7 @@
 #include <linux/posix_acl.h>
 #include <linux/posix_acl_xattr.h>
 #include <linux/atomic.h>
+#include <linux/fs_stack.h>
 #include "overlayfs.h"
 
 void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
@@ -174,7 +175,7 @@ static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
 	ovl_dentry_update(dentry, newdentry);
 	if (!hardlink) {
 		ovl_inode_update(inode, d_inode(newdentry));
-		ovl_copyattr(newdentry->d_inode, inode);
+		fsstack_copy_attr_all(inode, newdentry->d_inode);
 	} else {
 		WARN_ON(ovl_inode_real(inode, NULL) != d_inode(newdentry));
 		inc_nlink(inode);
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 7fb53d0..540caa6 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -11,6 +11,7 @@
 #include <linux/slab.h>
 #include <linux/xattr.h>
 #include <linux/posix_acl.h>
+#include <linux/fs_stack.h>
 #include "overlayfs.h"
 
 static int ovl_copy_up_truncate(struct dentry *dentry)
@@ -93,7 +94,7 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr)
 		err = notify_change(upperdentry, attr, NULL);
 		revert_creds(old_cred);
 		if (!err)
-			ovl_copyattr(upperdentry->d_inode, dentry->d_inode);
+			fsstack_copy_attr_all(dentry->d_inode, upperdentry->d_inode);
 		inode_unlock(upperdentry->d_inode);
 
 		if (winode)
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index e218e74..9f15785 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -197,15 +197,6 @@ bool ovl_is_private_xattr(const char *name);
 
 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode);
 struct inode *ovl_get_inode(struct super_block *sb, struct inode *realinode);
-static inline void ovl_copyattr(struct inode *from, struct inode *to)
-{
-	to->i_uid = from->i_uid;
-	to->i_gid = from->i_gid;
-	to->i_mode = from->i_mode;
-	to->i_atime = from->i_atime;
-	to->i_mtime = from->i_mtime;
-	to->i_ctime = from->i_ctime;
-}
 
 /* dir.c */
 extern const struct inode_operations ovl_dir_inode_operations;
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index edd46a0..91a3a60 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -20,6 +20,7 @@
 #include <linux/statfs.h>
 #include <linux/seq_file.h>
 #include <linux/posix_acl_xattr.h>
+#include <linux/fs_stack.h>
 #include "overlayfs.h"
 
 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
@@ -581,7 +582,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 		}
 		if (!inode)
 			goto out_free_oe;
-		ovl_copyattr(realdentry->d_inode, inode);
+		fsstack_copy_attr_all(inode, realdentry->d_inode);
 	}
 
 	revert_creds(old_cred);
@@ -1054,7 +1055,7 @@ ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
 
 	err = ovl_xattr_set(dentry, handler->name, value, size, flags);
 	if (!err)
-		ovl_copyattr(ovl_inode_real(inode, NULL), inode);
+		fsstack_copy_attr_all(inode, ovl_inode_real(inode, NULL));
 
 	return err;
 
@@ -1345,7 +1346,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 
 	realinode = d_inode(ovl_dentry_real(root_dentry));
 	ovl_inode_init(d_inode(root_dentry), realinode, !!upperpath.dentry);
-	ovl_copyattr(realinode, d_inode(root_dentry));
+	fsstack_copy_attr_all(d_inode(root_dentry), realinode);
 
 	sb->s_root = root_dentry;
 
-- 
2.7.4

[PATCH 2/2] ovl: use kernel facility for updating access time

[Quorum Laval]

Use fsstack_copy_attr_atime() instead of direct assignement.

Signed-off-by: Quorum Laval <quorum.laval@gmail.com>
---
 fs/overlayfs/inode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 540caa6..083cbdb 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -329,7 +329,7 @@ int ovl_update_time(struct inode *inode, struct timespec *ts, int flags)
 	ovl_path_upper(alias, &upperpath);
 	if (upperpath.dentry) {
 		touch_atime(&upperpath);
-		inode->i_atime = d_inode(upperpath.dentry)->i_atime;
+		fsstack_copy_attr_atime(inode, d_inode(upperpath.dentry));
 	}
 
 	dput(alias);
-- 
2.7.4

Re: [PATCH 1/2] ovl: use kernel facility for copying attributes

[Miklos Szeredi]

On Tue, Nov 15, 2016 at 5:54 PM, Quorum Laval <quorum.laval@gmail.com> wrote:
> Replace ovl_copyattr() by fsstack_copy_attr_all() and drop the definition of
> the former.

This isn't trivially correct, fsstack_copy_attr_all() copies more than
ovl_copyattr().   We need a better explanation for why it is correct
to copy all the other attributes as well.

Thanks,
Miklos

Re: [PATCH 2/2] ovl: use kernel facility for updating access time

[Miklos Szeredi]

On Tue, Nov 15, 2016 at 5:54 PM, Quorum Laval <quorum.laval@gmail.com> wrote:
> Use fsstack_copy_attr_atime() instead of direct assignement.

This one's correct, but what's the point?

Thanks,
Miklos