From 235ce9ed96bc624fe929f724883cc04b7a714ac2 Mon Sep 17 00:00:00 2001
From: Amir Goldstein <amir73il@gmail.com>
Date: Sun, 30 Aug 2020 23:28:03 +0300
Subject: [PATCH 01/13] ovl: check for incompatible features in work dir

An incompatible feature is marked by a non-empty directory nested
2 levels deep under "work" dir, e.g.:
workdir/work/incompat/volatile.

This commit checks for marked incompat features, warns about them
and fails to mount the overlay, for example:
  overlayfs: overlay with incompat feature 'volatile' cannot be mounted

Very old kernels (i.e. v3.18) will fail to remove a non-empty "work"
dir and fail the mount.  Newer kernels will fail to remove a "work"
dir with entries nested 3 levels and fall back to read-only mount.

User mounting with old kernel will see a warning like these in dmesg:
  overlayfs: cleanup of 'incompat/...' failed (-39)
  overlayfs: cleanup of 'work/incompat' failed (-39)
  overlayfs: cleanup of 'ovl-work/work' failed (-39)
  overlayfs: failed to create directory /vdf/ovl-work/work (errno: 17);
             mounting read-only

These warnings should give the hint to the user that:
1. mount failure is caused by backward incompatible features
2. mount failure can be resolved by manually removing the "work" directory

There is nothing preventing users on old kernels from manually removing
workdir entirely or mounting overlay with a new workdir, so this is in
no way a full proof backward compatibility enforcement, but only a best
effort.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/readdir.c | 32 ++++++++++++++++++++++++++++----
 fs/overlayfs/super.c   | 25 ++++++++++++++++++-------
 2 files changed, 46 insertions(+), 11 deletions(-)

diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 6918b98faeb6..9b0078aabaf9 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -1051,7 +1051,9 @@ int ovl_check_d_type_supported(struct path *realpath)
 	return rdd.d_type_supported;
 }
 
-static void ovl_workdir_cleanup_recurse(struct path *path, int level)
+#define OVL_INCOMPATDIR_NAME "incompat"
+
+static int ovl_workdir_cleanup_recurse(struct path *path, int level)
 {
 	int err;
 	struct inode *dir = path->dentry->d_inode;
@@ -1065,6 +1067,19 @@ static void ovl_workdir_cleanup_recurse(struct path *path, int level)
 		.root = &root,
 		.is_lowest = false,
 	};
+	bool incompat = false;
+
+	/*
+	 * The "work/incompat" directory is treated specially - if it is not
+	 * empty, instead of printing a generic error and mounting read-only,
+	 * we will error about incompat features and fail the mount.
+	 *
+	 * When called from ovl_indexdir_cleanup(), path->dentry->d_name.name
+	 * starts with '#'.
+	 */
+	if (level == 2 &&
+	    !strcmp(path->dentry->d_name.name, OVL_INCOMPATDIR_NAME))
+		incompat = true;
 
 	err = ovl_dir_read(path, &rdd);
 	if (err)
@@ -1079,17 +1094,25 @@ static void ovl_workdir_cleanup_recurse(struct path *path, int level)
 				continue;
 			if (p->len == 2 && p->name[1] == '.')
 				continue;
+		} else if (incompat) {
+			pr_err("overlay with incompat feature '%s' cannot be mounted\n",
+				p->name);
+			err = -EINVAL;
+			break;
 		}
 		dentry = lookup_one_len(p->name, path->dentry, p->len);
 		if (IS_ERR(dentry))
 			continue;
 		if (dentry->d_inode)
-			ovl_workdir_cleanup(dir, path->mnt, dentry, level);
+			err = ovl_workdir_cleanup(dir, path->mnt, dentry, level);
 		dput(dentry);
+		if (err)
+			break;
 	}
 	inode_unlock(dir);
 out:
 	ovl_cache_free(&list);
+	return err;
 }
 
 int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
@@ -1106,9 +1129,10 @@ int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
 		struct path path = { .mnt = mnt, .dentry = dentry };
 
 		inode_unlock(dir);
-		ovl_workdir_cleanup_recurse(&path, level + 1);
+		err = ovl_workdir_cleanup_recurse(&path, level + 1);
 		inode_lock_nested(dir, I_MUTEX_PARENT);
-		err = ovl_cleanup(dir, dentry);
+		if (!err)
+			err = ovl_cleanup(dir, dentry);
 	}
 
 	return err;
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 4b38141c2985..f82defec02c1 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -705,8 +705,12 @@ retry:
 				goto out_unlock;
 
 			retried = true;
-			ovl_workdir_cleanup(dir, mnt, work, 0);
+			err = ovl_workdir_cleanup(dir, mnt, work, 0);
 			dput(work);
+			if (err == -EINVAL) {
+				work = ERR_PTR(err);
+				goto out_unlock;
+			}
 			goto retry;
 		}
 
@@ -1203,7 +1207,7 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 			    struct path *workpath)
 {
 	struct vfsmount *mnt = ovl_upper_mnt(ofs);
-	struct dentry *temp;
+	struct dentry *temp, *workdir;
 	bool rename_whiteout;
 	bool d_type;
 	int fh_type;
@@ -1213,10 +1217,13 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 	if (err)
 		return err;
 
-	ofs->workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false);
-	if (!ofs->workdir)
+	workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false);
+	err = PTR_ERR(workdir);
+	if (IS_ERR_OR_NULL(workdir))
 		goto out;
 
+	ofs->workdir = workdir;
+
 	err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir");
 	if (err)
 		goto out;
@@ -1347,6 +1354,7 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
 			    struct ovl_entry *oe, struct path *upperpath)
 {
 	struct vfsmount *mnt = ovl_upper_mnt(ofs);
+	struct dentry *indexdir;
 	int err;
 
 	err = mnt_want_write(mnt);
@@ -1366,9 +1374,12 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
 	ofs->workdir_trap = NULL;
 	dput(ofs->workdir);
 	ofs->workdir = NULL;
-	ofs->indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true);
-	if (ofs->indexdir) {
-		ofs->workdir = dget(ofs->indexdir);
+	indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true);
+	if (IS_ERR(indexdir)) {
+		err = PTR_ERR(indexdir);
+	} else if (indexdir) {
+		ofs->indexdir = indexdir;
+		ofs->workdir = dget(indexdir);
 
 		err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap,
 				     "indexdir");

From c86243b090bc25f81abe33ddfa9fe833e02c4d64 Mon Sep 17 00:00:00 2001
From: Vivek Goyal <vgoyal@redhat.com>
Date: Mon, 31 Aug 2020 14:15:29 -0400
Subject: [PATCH 02/13] ovl: provide a mount option "volatile"

Container folks are complaining that dnf/yum issues too many sync while
installing packages and this slows down the image build. Build requirement
is such that they don't care if a node goes down while build was still
going on. In that case, they will simply throw away unfinished layer and
start new build. So they don't care about syncing intermediate state to the
disk and hence don't want to pay the price associated with sync.

So they are asking for mount options where they can disable sync on overlay
mount point.

They primarily seem to have two use cases.

- For building images, they will mount overlay with nosync and then sync
  upper layer after unmounting overlay and reuse upper as lower for next
  layer.

- For running containers, they don't seem to care about syncing upper layer
  because if node goes down, they will simply throw away upper layer and
  create a fresh one.

So this patch provides a mount option "volatile" which disables all forms
of sync. Now it is caller's responsibility to throw away upper if system
crashes or shuts down and start fresh.

With "volatile", I am seeing roughly 20% speed up in my VM where I am just
installing emacs in an image. Installation time drops from 31 seconds to 25
seconds when nosync option is used. This is for the case of building on top
of an image where all packages are already cached. That way I take out the
network operations latency out of the measurement.

Giuseppe is also looking to cut down on number of iops done on the disk. He
is complaining that often in cloud their VMs are throttled if they cross
the limit. This option can help them where they reduce number of iops (by
cutting down on frequent sync and writebacks).

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 Documentation/filesystems/overlayfs.rst | 19 +++++++
 fs/overlayfs/copy_up.c                  | 12 ++--
 fs/overlayfs/file.c                     | 10 +++-
 fs/overlayfs/ovl_entry.h                |  6 ++
 fs/overlayfs/readdir.c                  |  3 +
 fs/overlayfs/super.c                    | 74 ++++++++++++++++++++++++-
 6 files changed, 116 insertions(+), 8 deletions(-)

diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst
index 8ea83a51c266..580ab9a0fe31 100644
--- a/Documentation/filesystems/overlayfs.rst
+++ b/Documentation/filesystems/overlayfs.rst
@@ -564,6 +564,25 @@ Note: the mount options index=off,nfs_export=on are conflicting for a
 read-write mount and will result in an error.
 
 
+Volatile mount
+--------------
+
+This is enabled with the "volatile" mount option.  Volatile mounts are not
+guaranteed to survive a crash.  It is strongly recommended that volatile
+mounts are only used if data written to the overlay can be recreated
+without significant effort.
+
+The advantage of mounting with the "volatile" option is that all forms of
+sync calls to the upper filesystem are omitted.
+
+When overlay is mounted with "volatile" option, the directory
+"$workdir/work/incompat/volatile" is created.  During next mount, overlay
+checks for this directory and refuses to mount if present. This is a strong
+indicator that user should throw away upper and work directories and create
+fresh one. In very limited cases where the user knows that the system has
+not crashed and contents of upperdir are intact, The "volatile" directory
+can be removed.
+
 Testsuite
 ---------
 
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index d07fb92b7253..9d17e42d184b 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -128,7 +128,8 @@ out:
 	return error;
 }
 
-static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
+static int ovl_copy_up_data(struct ovl_fs *ofs, struct path *old,
+			    struct path *new, loff_t len)
 {
 	struct file *old_file;
 	struct file *new_file;
@@ -218,7 +219,7 @@ static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
 		len -= bytes;
 	}
 out:
-	if (!error)
+	if (!error && ovl_should_sync(ofs))
 		error = vfs_fsync(new_file, 0);
 	fput(new_file);
 out_fput:
@@ -484,6 +485,7 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c)
 
 static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
 {
+	struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
 	int err;
 
 	/*
@@ -499,7 +501,8 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
 		upperpath.dentry = temp;
 
 		ovl_path_lowerdata(c->dentry, &datapath);
-		err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
+		err = ovl_copy_up_data(ofs, &datapath, &upperpath,
+				       c->stat.size);
 		if (err)
 			return err;
 	}
@@ -784,6 +787,7 @@ static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
 /* Copy up data of an inode which was copied up metadata only in the past. */
 static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
 {
+	struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
 	struct path upperpath, datapath;
 	int err;
 	char *capability = NULL;
@@ -804,7 +808,7 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
 			goto out;
 	}
 
-	err = ovl_copy_up_data(&datapath, &upperpath, c->stat.size);
+	err = ovl_copy_up_data(ofs, &datapath, &upperpath, c->stat.size);
 	if (err)
 		goto out_free;
 
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 0d940e29d62b..3582c3ae819c 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -331,6 +331,7 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
 	struct fd real;
 	const struct cred *old_cred;
 	ssize_t ret;
+	int ifl = iocb->ki_flags;
 
 	if (!iov_iter_count(iter))
 		return 0;
@@ -346,11 +347,14 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
 	if (ret)
 		goto out_unlock;
 
+	if (!ovl_should_sync(OVL_FS(inode->i_sb)))
+		ifl &= ~(IOCB_DSYNC | IOCB_SYNC);
+
 	old_cred = ovl_override_creds(file_inode(file)->i_sb);
 	if (is_sync_kiocb(iocb)) {
 		file_start_write(real.file);
 		ret = vfs_iter_write(real.file, iter, &iocb->ki_pos,
-				     ovl_iocb_to_rwf(iocb->ki_flags));
+				     ovl_iocb_to_rwf(ifl));
 		file_end_write(real.file);
 		/* Update size */
 		ovl_copyattr(ovl_inode_real(inode), inode);
@@ -370,6 +374,7 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
 		real.flags = 0;
 		aio_req->orig_iocb = iocb;
 		kiocb_clone(&aio_req->iocb, iocb, real.file);
+		aio_req->iocb.ki_flags = ifl;
 		aio_req->iocb.ki_complete = ovl_aio_rw_complete;
 		ret = vfs_iocb_iter_write(real.file, &aio_req->iocb, iter);
 		if (ret != -EIOCBQUEUED)
@@ -433,6 +438,9 @@ static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 	const struct cred *old_cred;
 	int ret;
 
+	if (!ovl_should_sync(OVL_FS(file_inode(file)->i_sb)))
+		return 0;
+
 	ret = ovl_real_fdget_meta(file, &real, !datasync);
 	if (ret)
 		return ret;
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index b429c80879ee..1b5a2094df8e 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -17,6 +17,7 @@ struct ovl_config {
 	bool nfs_export;
 	int xino;
 	bool metacopy;
+	bool ovl_volatile;
 };
 
 struct ovl_sb {
@@ -90,6 +91,11 @@ static inline struct ovl_fs *OVL_FS(struct super_block *sb)
 	return (struct ovl_fs *)sb->s_fs_info;
 }
 
+static inline bool ovl_should_sync(struct ovl_fs *ofs)
+{
+	return !ofs->config.ovl_volatile;
+}
+
 /* private information held for every overlayfs dentry */
 struct ovl_entry {
 	union {
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 9b0078aabaf9..f8cc15533afa 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -863,6 +863,9 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
 	if (!OVL_TYPE_UPPER(ovl_path_type(dentry)))
 		return 0;
 
+	if (!ovl_should_sync(OVL_FS(dentry->d_sb)))
+		return 0;
+
 	/*
 	 * Need to check if we started out being a lower dir, but got copied up
 	 */
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index f82defec02c1..8b419ef78502 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -264,6 +264,8 @@ static int ovl_sync_fs(struct super_block *sb, int wait)
 	if (!ovl_upper_mnt(ofs))
 		return 0;
 
+	if (!ovl_should_sync(ofs))
+		return 0;
 	/*
 	 * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC).
 	 * All the super blocks will be iterated, including upper_sb.
@@ -362,6 +364,8 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
 	if (ofs->config.metacopy != ovl_metacopy_def)
 		seq_printf(m, ",metacopy=%s",
 			   ofs->config.metacopy ? "on" : "off");
+	if (ofs->config.ovl_volatile)
+		seq_puts(m, ",volatile");
 	return 0;
 }
 
@@ -376,9 +380,11 @@ static int ovl_remount(struct super_block *sb, int *flags, char *data)
 
 	if (*flags & SB_RDONLY && !sb_rdonly(sb)) {
 		upper_sb = ovl_upper_mnt(ofs)->mnt_sb;
-		down_read(&upper_sb->s_umount);
-		ret = sync_filesystem(upper_sb);
-		up_read(&upper_sb->s_umount);
+		if (ovl_should_sync(ofs)) {
+			down_read(&upper_sb->s_umount);
+			ret = sync_filesystem(upper_sb);
+			up_read(&upper_sb->s_umount);
+		}
 	}
 
 	return ret;
@@ -411,6 +417,7 @@ enum {
 	OPT_XINO_AUTO,
 	OPT_METACOPY_ON,
 	OPT_METACOPY_OFF,
+	OPT_VOLATILE,
 	OPT_ERR,
 };
 
@@ -429,6 +436,7 @@ static const match_table_t ovl_tokens = {
 	{OPT_XINO_AUTO,			"xino=auto"},
 	{OPT_METACOPY_ON,		"metacopy=on"},
 	{OPT_METACOPY_OFF,		"metacopy=off"},
+	{OPT_VOLATILE,			"volatile"},
 	{OPT_ERR,			NULL}
 };
 
@@ -573,6 +581,10 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
 			metacopy_opt = true;
 			break;
 
+		case OPT_VOLATILE:
+			config->ovl_volatile = true;
+			break;
+
 		default:
 			pr_err("unrecognized mount option \"%s\" or missing value\n",
 					p);
@@ -595,6 +607,11 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config)
 		config->index = false;
 	}
 
+	if (!config->upperdir && config->ovl_volatile) {
+		pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n");
+		config->ovl_volatile = false;
+	}
+
 	err = ovl_parse_redirect_mode(config, config->redirect_mode);
 	if (err)
 		return err;
@@ -1203,6 +1220,45 @@ out_unlock:
 	return err;
 }
 
+static struct dentry *ovl_lookup_or_create(struct dentry *parent,
+					   const char *name, umode_t mode)
+{
+	size_t len = strlen(name);
+	struct dentry *child;
+
+	inode_lock_nested(parent->d_inode, I_MUTEX_PARENT);
+	child = lookup_one_len(name, parent, len);
+	if (!IS_ERR(child) && !child->d_inode)
+		child = ovl_create_real(parent->d_inode, child,
+					OVL_CATTR(mode));
+	inode_unlock(parent->d_inode);
+	dput(parent);
+
+	return child;
+}
+
+/*
+ * Creates $workdir/work/incompat/volatile/dirty file if it is not already
+ * present.
+ */
+static int ovl_create_volatile_dirty(struct ovl_fs *ofs)
+{
+	unsigned int ctr;
+	struct dentry *d = dget(ofs->workbasedir);
+	static const char *const volatile_path[] = {
+		OVL_WORKDIR_NAME, "incompat", "volatile", "dirty"
+	};
+	const char *const *name = volatile_path;
+
+	for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) {
+		d = ovl_lookup_or_create(d, *name, ctr > 1 ? S_IFDIR : S_IFREG);
+		if (IS_ERR(d))
+			return PTR_ERR(d);
+	}
+	dput(d);
+	return 0;
+}
+
 static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 			    struct path *workpath)
 {
@@ -1286,6 +1342,18 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 		goto out;
 	}
 
+	/*
+	 * For volatile mount, create a incompat/volatile/dirty file to keep
+	 * track of it.
+	 */
+	if (ofs->config.ovl_volatile) {
+		err = ovl_create_volatile_dirty(ofs);
+		if (err < 0) {
+			pr_err("Failed to create volatile/dirty file.\n");
+			goto out;
+		}
+	}
+
 	/* Check if upper/work fs supports file handles */
 	fh_type = ovl_can_decode_fh(ofs->workdir->d_sb);
 	if (ofs->config.index && !fh_type) {

From fee0f2980a2e89f9929ae0355464064cdc47e8f0 Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@redhat.com>
Date: Wed, 2 Sep 2020 10:58:48 +0200
Subject: [PATCH 03/13] duplicate ovl_getxattr()

ovl_getattr() returns the value of an xattr in a kmalloced buffer.  There
are two callers:

 ovl_copy_up_meta_inode_data()	(copy_up.c)
 ovl_get_redirect_xattr()	(util.c)

This patch just copies ovl_getxattr() to copy_up.c, the following patches
will deal with the differences in idividual callers.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/copy_up.c   | 33 +++++++++++++++++++++++++++++++++
 fs/overlayfs/overlayfs.h |  2 --
 fs/overlayfs/util.c      |  4 ++--
 3 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 9d17e42d184b..6a471da0284f 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -784,6 +784,39 @@ static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
 	return true;
 }
 
+static ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
+			    size_t padding)
+{
+	ssize_t res;
+	char *buf = NULL;
+
+	res = vfs_getxattr(dentry, name, NULL, 0);
+	if (res < 0) {
+		if (res == -ENODATA || res == -EOPNOTSUPP)
+			return -ENODATA;
+		goto fail;
+	}
+
+	if (res != 0) {
+		buf = kzalloc(res + padding, GFP_KERNEL);
+		if (!buf)
+			return -ENOMEM;
+
+		res = vfs_getxattr(dentry, name, buf, res);
+		if (res < 0)
+			goto fail;
+	}
+	*value = buf;
+
+	return res;
+
+fail:
+	pr_warn_ratelimited("failed to get xattr %s: err=%zi)\n",
+			    name, res);
+	kfree(buf);
+	return res;
+}
+
 /* Copy up data of an inode which was copied up metadata only in the past. */
 static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
 {
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 29bc1ec699e7..ebc03e086300 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -299,8 +299,6 @@ int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
 int ovl_check_metacopy_xattr(struct dentry *dentry);
 bool ovl_is_metacopy_dentry(struct dentry *dentry);
 char *ovl_get_redirect_xattr(struct dentry *dentry, int padding);
-ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
-		     size_t padding);
 
 static inline bool ovl_is_impuredir(struct dentry *dentry)
 {
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 56c1f89f20c9..feca16a47f57 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -882,8 +882,8 @@ bool ovl_is_metacopy_dentry(struct dentry *dentry)
 	return (oe->numlower > 1);
 }
 
-ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
-		     size_t padding)
+static ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
+			    size_t padding)
 {
 	ssize_t res;
 	char *buf = NULL;

From de7a52c9c60b4763f43f862bb60f657f7fa1cfcc Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@redhat.com>
Date: Wed, 2 Sep 2020 10:58:48 +0200
Subject: [PATCH 04/13] ovl: clean up ovl_getxattr() in copy_up.c

Lose the padding and the failure message (in line with other parts of the
copy up process).  Return zero for both nonexistent or empty xattr.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/copy_up.c | 32 +++++++++++---------------------
 1 file changed, 11 insertions(+), 21 deletions(-)

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 6a471da0284f..cf0b6406748d 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -784,36 +784,26 @@ static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
 	return true;
 }
 
-static ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
-			    size_t padding)
+static ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value)
 {
 	ssize_t res;
-	char *buf = NULL;
+	char *buf;
 
 	res = vfs_getxattr(dentry, name, NULL, 0);
-	if (res < 0) {
-		if (res == -ENODATA || res == -EOPNOTSUPP)
-			return -ENODATA;
-		goto fail;
-	}
+	if (res == -ENODATA || res == -EOPNOTSUPP)
+		res = 0;
 
-	if (res != 0) {
-		buf = kzalloc(res + padding, GFP_KERNEL);
+	if (res > 0) {
+		buf = kzalloc(res, GFP_KERNEL);
 		if (!buf)
 			return -ENOMEM;
 
 		res = vfs_getxattr(dentry, name, buf, res);
 		if (res < 0)
-			goto fail;
+			kfree(buf);
+		else
+			*value = buf;
 	}
-	*value = buf;
-
-	return res;
-
-fail:
-	pr_warn_ratelimited("failed to get xattr %s: err=%zi)\n",
-			    name, res);
-	kfree(buf);
 	return res;
 }
 
@@ -836,8 +826,8 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
 
 	if (c->stat.size) {
 		err = cap_size = ovl_getxattr(upperpath.dentry, XATTR_NAME_CAPS,
-					      &capability, 0);
-		if (err < 0 && err != -ENODATA)
+					      &capability);
+		if (cap_size < 0)
 			goto out;
 	}
 

From 92f0d6c9cfcf1f1fa54251353a9c4cd63fa30544 Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@redhat.com>
Date: Wed, 2 Sep 2020 10:58:48 +0200
Subject: [PATCH 05/13] ovl: fold ovl_getxattr() into ovl_get_redirect_xattr()

This is a partial revert (with some cleanups) of commit 993a0b2aec52 ("ovl:
Do not lose security.capability xattr over metadata file copy-up"), which
introduced ovl_getxattr() in the first place.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/util.c | 53 +++++++++++++++------------------------------
 1 file changed, 17 insertions(+), 36 deletions(-)

diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index feca16a47f57..4cc1366c96a6 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -882,49 +882,26 @@ bool ovl_is_metacopy_dentry(struct dentry *dentry)
 	return (oe->numlower > 1);
 }
 
-static ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value,
-			    size_t padding)
-{
-	ssize_t res;
-	char *buf = NULL;
-
-	res = vfs_getxattr(dentry, name, NULL, 0);
-	if (res < 0) {
-		if (res == -ENODATA || res == -EOPNOTSUPP)
-			return -ENODATA;
-		goto fail;
-	}
-
-	if (res != 0) {
-		buf = kzalloc(res + padding, GFP_KERNEL);
-		if (!buf)
-			return -ENOMEM;
-
-		res = vfs_getxattr(dentry, name, buf, res);
-		if (res < 0)
-			goto fail;
-	}
-	*value = buf;
-
-	return res;
-
-fail:
-	pr_warn_ratelimited("failed to get xattr %s: err=%zi)\n",
-			    name, res);
-	kfree(buf);
-	return res;
-}
-
 char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
 {
 	int res;
 	char *s, *next, *buf = NULL;
 
-	res = ovl_getxattr(dentry, OVL_XATTR_REDIRECT, &buf, padding + 1);
-	if (res == -ENODATA)
+	res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, NULL, 0);
+	if (res == -ENODATA || res == -EOPNOTSUPP)
 		return NULL;
 	if (res < 0)
-		return ERR_PTR(res);
+		goto fail;
+	if (res == 0)
+		goto invalid;
+
+	buf = kzalloc(res + padding + 1, GFP_KERNEL);
+	if (!buf)
+		return ERR_PTR(-ENOMEM);
+
+	res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, buf, res);
+	if (res < 0)
+		goto fail;
 	if (res == 0)
 		goto invalid;
 
@@ -943,6 +920,10 @@ char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
 invalid:
 	pr_warn_ratelimited("invalid redirect (%s)\n", buf);
 	res = -EINVAL;
+	goto err_free;
+fail:
+	pr_warn_ratelimited("failed to get redirect (%i)\n", res);
+err_free:
 	kfree(buf);
 	return ERR_PTR(res);
 }

From d5dc7486e8c6dd860b81842cd5d999e3782d5795 Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@redhat.com>
Date: Wed, 2 Sep 2020 10:58:48 +0200
Subject: [PATCH 06/13] ovl: use ovl_do_getxattr() for private xattr

Use the convention of calling ovl_do_foo() for operations which are overlay
specific.

This patch is a no-op, and will have significance for supporting
"user.overlay." xattr namespace.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/inode.c     |  3 ++-
 fs/overlayfs/namei.c     |  4 ++--
 fs/overlayfs/overlayfs.h |  6 ++++++
 fs/overlayfs/util.c      | 10 +++++-----
 4 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 8be6cd264f66..3297a5dbaac1 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -748,7 +748,8 @@ unsigned int ovl_get_nlink(struct dentry *lowerdentry,
 	if (!lowerdentry || !upperdentry || d_inode(lowerdentry)->i_nlink == 1)
 		return fallback;
 
-	err = vfs_getxattr(upperdentry, OVL_XATTR_NLINK, &buf, sizeof(buf) - 1);
+	err = ovl_do_getxattr(upperdentry, OVL_XATTR_NLINK,
+			      &buf, sizeof(buf) - 1);
 	if (err < 0)
 		goto fail;
 
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index f7d4358db637..7b5ee84b5440 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -109,7 +109,7 @@ static struct ovl_fh *ovl_get_fh(struct dentry *dentry, const char *name)
 	int res, err;
 	struct ovl_fh *fh = NULL;
 
-	res = vfs_getxattr(dentry, name, NULL, 0);
+	res = ovl_do_getxattr(dentry, name, NULL, 0);
 	if (res < 0) {
 		if (res == -ENODATA || res == -EOPNOTSUPP)
 			return NULL;
@@ -123,7 +123,7 @@ static struct ovl_fh *ovl_get_fh(struct dentry *dentry, const char *name)
 	if (!fh)
 		return ERR_PTR(-ENOMEM);
 
-	res = vfs_getxattr(dentry, name, fh->buf, res);
+	res = ovl_do_getxattr(dentry, name, fh->buf, res);
 	if (res < 0)
 		goto fail;
 
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index ebc03e086300..a5a7c192819c 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -170,6 +170,12 @@ static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
 	return err;
 }
 
+static inline ssize_t ovl_do_getxattr(struct dentry *dentry, const char *name,
+				      void *value, size_t size)
+{
+	return vfs_getxattr(dentry, name, value, size);
+}
+
 static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
 				  const void *value, size_t size, int flags)
 {
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 4cc1366c96a6..d2a77659e883 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -548,7 +548,7 @@ bool ovl_check_origin_xattr(struct dentry *dentry)
 {
 	int res;
 
-	res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0);
+	res = ovl_do_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0);
 
 	/* Zero size value means "copied up but origin unknown" */
 	if (res >= 0)
@@ -565,7 +565,7 @@ bool ovl_check_dir_xattr(struct dentry *dentry, const char *name)
 	if (!d_is_dir(dentry))
 		return false;
 
-	res = vfs_getxattr(dentry, name, &val, 1);
+	res = ovl_do_getxattr(dentry, name, &val, 1);
 	if (res == 1 && val == 'y')
 		return true;
 
@@ -853,7 +853,7 @@ int ovl_check_metacopy_xattr(struct dentry *dentry)
 	if (!S_ISREG(d_inode(dentry)->i_mode))
 		return 0;
 
-	res = vfs_getxattr(dentry, OVL_XATTR_METACOPY, NULL, 0);
+	res = ovl_do_getxattr(dentry, OVL_XATTR_METACOPY, NULL, 0);
 	if (res < 0) {
 		if (res == -ENODATA || res == -EOPNOTSUPP)
 			return 0;
@@ -887,7 +887,7 @@ char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
 	int res;
 	char *s, *next, *buf = NULL;
 
-	res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, NULL, 0);
+	res = ovl_do_getxattr(dentry, OVL_XATTR_REDIRECT, NULL, 0);
 	if (res == -ENODATA || res == -EOPNOTSUPP)
 		return NULL;
 	if (res < 0)
@@ -899,7 +899,7 @@ char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
 	if (!buf)
 		return ERR_PTR(-ENOMEM);
 
-	res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, buf, res);
+	res = ovl_do_getxattr(dentry, OVL_XATTR_REDIRECT, buf, res);
 	if (res < 0)
 		goto fail;
 	if (res == 0)

From 7109704705a4d80516de00779bba38b3844bff13 Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@redhat.com>
Date: Wed, 2 Sep 2020 10:58:48 +0200
Subject: [PATCH 07/13] ovl: adhere to the vfs_ vs. ovl_do_ conventions for
 xattrs

Call ovl_do_*xattr() when accessing an overlay private xattr, vfs_*xattr()
otherwise.

This has an effect on debug output, which is made more consistent by this
patch.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/copy_up.c | 6 +++---
 fs/overlayfs/super.c   | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index cf0b6406748d..ebce234f092b 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -840,14 +840,14 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
 	 * don't want that to happen for normal copy-up operation.
 	 */
 	if (capability) {
-		err = ovl_do_setxattr(upperpath.dentry, XATTR_NAME_CAPS,
-				      capability, cap_size, 0);
+		err = vfs_setxattr(upperpath.dentry, XATTR_NAME_CAPS,
+				   capability, cap_size, 0);
 		if (err)
 			goto out_free;
 	}
 
 
-	err = vfs_removexattr(upperpath.dentry, OVL_XATTR_METACOPY);
+	err = ovl_do_removexattr(upperpath.dentry, OVL_XATTR_METACOPY);
 	if (err)
 		goto out_free;
 
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 8b419ef78502..9e4c6ce3ce57 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1327,7 +1327,7 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 		pr_warn("upper fs does not support xattr, falling back to index=off and metacopy=off.\n");
 		err = 0;
 	} else {
-		vfs_removexattr(ofs->workdir, OVL_XATTR_OPAQUE);
+		ovl_do_removexattr(ofs->workdir, OVL_XATTR_OPAQUE);
 	}
 
 	/*

From 26150ab5eae16cef151d5e6ad5b5b38544dbf88a Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@redhat.com>
Date: Wed, 2 Sep 2020 10:58:48 +0200
Subject: [PATCH 08/13] ovl: drop flags argument from ovl_do_setxattr()

All callers pass zero flags to ovl_do_setxattr().  So drop this argument.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/copy_up.c   | 2 +-
 fs/overlayfs/inode.c     | 2 +-
 fs/overlayfs/namei.c     | 2 +-
 fs/overlayfs/overlayfs.h | 8 ++++----
 fs/overlayfs/super.c     | 2 +-
 fs/overlayfs/util.c      | 2 +-
 6 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index ebce234f092b..4dd5a1bc716b 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -364,7 +364,7 @@ static int ovl_set_upper_fh(struct dentry *upper, struct dentry *index)
 	if (IS_ERR(fh))
 		return PTR_ERR(fh);
 
-	err = ovl_do_setxattr(index, OVL_XATTR_UPPER, fh->buf, fh->fb.len, 0);
+	err = ovl_do_setxattr(index, OVL_XATTR_UPPER, fh->buf, fh->fb.len);
 
 	kfree(fh);
 	return err;
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 3297a5dbaac1..3b7ed7cd2338 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -723,7 +723,7 @@ static int ovl_set_nlink_common(struct dentry *dentry,
 		return -EIO;
 
 	return ovl_do_setxattr(ovl_dentry_upper(dentry),
-			       OVL_XATTR_NLINK, buf, len, 0);
+			       OVL_XATTR_NLINK, buf, len);
 }
 
 int ovl_set_nlink_upper(struct dentry *dentry)
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 7b5ee84b5440..18ccf7450603 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -456,7 +456,7 @@ int ovl_verify_set_fh(struct dentry *dentry, const char *name,
 
 	err = ovl_verify_fh(dentry, name, fh);
 	if (set && err == -ENODATA)
-		err = ovl_do_setxattr(dentry, name, fh->buf, fh->fb.len, 0);
+		err = ovl_do_setxattr(dentry, name, fh->buf, fh->fb.len);
 	if (err)
 		goto fail;
 
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index a5a7c192819c..5f108233f03b 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -177,11 +177,11 @@ static inline ssize_t ovl_do_getxattr(struct dentry *dentry, const char *name,
 }
 
 static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
-				  const void *value, size_t size, int flags)
+				  const void *value, size_t size)
 {
-	int err = vfs_setxattr(dentry, name, value, size, flags);
-	pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0x%x) = %i\n",
-		 dentry, name, min((int)size, 48), value, size, flags, err);
+	int err = vfs_setxattr(dentry, name, value, size, 0);
+	pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
+		 dentry, name, min((int)size, 48), value, size, err);
 	return err;
 }
 
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 9e4c6ce3ce57..fcfb32aaca9a 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1319,7 +1319,7 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 	/*
 	 * Check if upper/work fs supports trusted.overlay.* xattr
 	 */
-	err = ovl_do_setxattr(ofs->workdir, OVL_XATTR_OPAQUE, "0", 1, 0);
+	err = ovl_do_setxattr(ofs->workdir, OVL_XATTR_OPAQUE, "0", 1);
 	if (err) {
 		ofs->noxattr = true;
 		ofs->config.index = false;
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index d2a77659e883..7d86dba0db68 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -582,7 +582,7 @@ int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
 	if (ofs->noxattr)
 		return xerr;
 
-	err = ovl_do_setxattr(upperdentry, name, value, size, 0);
+	err = ovl_do_setxattr(upperdentry, name, value, size);
 
 	if (err == -EOPNOTSUPP) {
 		pr_warn("cannot set %s xattr on upper\n", name);

From 610afc0bd40882181718be2ae1e0264466bba2c7 Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@redhat.com>
Date: Wed, 2 Sep 2020 10:58:49 +0200
Subject: [PATCH 09/13] ovl: pass ovl_fs down to functions accessing private
 xattrs

This paves the way for optionally using the "user.overlay." xattr
namespace.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/copy_up.c   | 16 ++++++-----
 fs/overlayfs/dir.c       |  2 +-
 fs/overlayfs/export.c    |  2 +-
 fs/overlayfs/inode.c     | 22 +++++++++-------
 fs/overlayfs/namei.c     | 57 +++++++++++++++++++++-------------------
 fs/overlayfs/overlayfs.h | 51 ++++++++++++++++++++---------------
 fs/overlayfs/readdir.c   |  3 ++-
 fs/overlayfs/super.c     | 18 +++++++------
 fs/overlayfs/util.c      | 22 +++++++++-------
 9 files changed, 107 insertions(+), 86 deletions(-)

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 4dd5a1bc716b..955ecd4030f0 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -43,7 +43,8 @@ static bool ovl_must_copy_xattr(const char *name)
 	       !strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN);
 }
 
-int ovl_copy_xattr(struct dentry *old, struct dentry *new)
+int ovl_copy_xattr(struct super_block *sb, struct dentry *old,
+		   struct dentry *new)
 {
 	ssize_t list_size, size, value_size = 0;
 	char *buf, *name, *value = NULL;
@@ -81,7 +82,7 @@ int ovl_copy_xattr(struct dentry *old, struct dentry *new)
 		}
 		list_size -= slen;
 
-		if (ovl_is_private_xattr(name))
+		if (ovl_is_private_xattr(sb, name))
 			continue;
 retry:
 		size = vfs_getxattr(old, name, value, value_size);
@@ -355,7 +356,8 @@ int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
 }
 
 /* Store file handle of @upper dir in @index dir entry */
-static int ovl_set_upper_fh(struct dentry *upper, struct dentry *index)
+static int ovl_set_upper_fh(struct ovl_fs *ofs, struct dentry *upper,
+			    struct dentry *index)
 {
 	const struct ovl_fh *fh;
 	int err;
@@ -364,7 +366,7 @@ static int ovl_set_upper_fh(struct dentry *upper, struct dentry *index)
 	if (IS_ERR(fh))
 		return PTR_ERR(fh);
 
-	err = ovl_do_setxattr(index, OVL_XATTR_UPPER, fh->buf, fh->fb.len);
+	err = ovl_do_setxattr(ofs, index, OVL_XATTR_UPPER, fh->buf, fh->fb.len);
 
 	kfree(fh);
 	return err;
@@ -409,7 +411,7 @@ static int ovl_create_index(struct dentry *dentry, struct dentry *origin,
 	if (IS_ERR(temp))
 		goto free_name;
 
-	err = ovl_set_upper_fh(upper, temp);
+	err = ovl_set_upper_fh(OVL_FS(dentry->d_sb), upper, temp);
 	if (err)
 		goto out;
 
@@ -507,7 +509,7 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
 			return err;
 	}
 
-	err = ovl_copy_xattr(c->lowerpath.dentry, temp);
+	err = ovl_copy_xattr(c->dentry->d_sb, c->lowerpath.dentry, temp);
 	if (err)
 		return err;
 
@@ -847,7 +849,7 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
 	}
 
 
-	err = ovl_do_removexattr(upperpath.dentry, OVL_XATTR_METACOPY);
+	err = ovl_do_removexattr(ofs, upperpath.dentry, OVL_XATTR_METACOPY);
 	if (err)
 		goto out_free;
 
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 1bba4813f9cb..28a075b5f5b2 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -394,7 +394,7 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
 	if (IS_ERR(opaquedir))
 		goto out_unlock;
 
-	err = ovl_copy_xattr(upper, opaquedir);
+	err = ovl_copy_xattr(dentry->d_sb, upper, opaquedir);
 	if (err)
 		goto out_cleanup;
 
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index 0e696f72cf65..ed35be3fafc6 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -752,7 +752,7 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb,
 			goto out_err;
 	}
 	if (index) {
-		err = ovl_verify_origin(index, origin.dentry, false);
+		err = ovl_verify_origin(ofs, index, origin.dentry, false);
 		if (err)
 			goto out_err;
 	}
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 3b7ed7cd2338..96666fe327de 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -327,7 +327,7 @@ static const char *ovl_get_link(struct dentry *dentry,
 	return p;
 }
 
-bool ovl_is_private_xattr(const char *name)
+bool ovl_is_private_xattr(struct super_block *sb, const char *name)
 {
 	return strncmp(name, OVL_XATTR_PREFIX,
 		       sizeof(OVL_XATTR_PREFIX) - 1) == 0;
@@ -391,14 +391,14 @@ int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
 	return res;
 }
 
-static bool ovl_can_list(const char *s)
+static bool ovl_can_list(struct super_block *sb, const char *s)
 {
 	/* List all non-trusted xatts */
 	if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0)
 		return true;
 
 	/* Never list trusted.overlay, list other trusted for superuser only */
-	return !ovl_is_private_xattr(s) &&
+	return !ovl_is_private_xattr(sb, s) &&
 	       ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN);
 }
 
@@ -425,7 +425,7 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
 			return -EIO;
 
 		len -= slen;
-		if (!ovl_can_list(s)) {
+		if (!ovl_can_list(dentry->d_sb, s)) {
 			res -= slen;
 			memmove(s, s + slen, len);
 		} else {
@@ -722,7 +722,7 @@ static int ovl_set_nlink_common(struct dentry *dentry,
 	if (WARN_ON(len >= sizeof(buf)))
 		return -EIO;
 
-	return ovl_do_setxattr(ovl_dentry_upper(dentry),
+	return ovl_do_setxattr(OVL_FS(inode->i_sb), ovl_dentry_upper(dentry),
 			       OVL_XATTR_NLINK, buf, len);
 }
 
@@ -736,7 +736,7 @@ int ovl_set_nlink_lower(struct dentry *dentry)
 	return ovl_set_nlink_common(dentry, ovl_dentry_lower(dentry), "L%+i");
 }
 
-unsigned int ovl_get_nlink(struct dentry *lowerdentry,
+unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
 			   struct dentry *upperdentry,
 			   unsigned int fallback)
 {
@@ -748,7 +748,7 @@ unsigned int ovl_get_nlink(struct dentry *lowerdentry,
 	if (!lowerdentry || !upperdentry || d_inode(lowerdentry)->i_nlink == 1)
 		return fallback;
 
-	err = ovl_do_getxattr(upperdentry, OVL_XATTR_NLINK,
+	err = ovl_do_getxattr(ofs, upperdentry, OVL_XATTR_NLINK,
 			      &buf, sizeof(buf) - 1);
 	if (err < 0)
 		goto fail;
@@ -947,6 +947,7 @@ static struct inode *ovl_iget5(struct super_block *sb, struct inode *newinode,
 struct inode *ovl_get_inode(struct super_block *sb,
 			    struct ovl_inode_params *oip)
 {
+	struct ovl_fs *ofs = OVL_FS(sb);
 	struct dentry *upperdentry = oip->upperdentry;
 	struct ovl_path *lowerpath = oip->lowerpath;
 	struct inode *realinode = upperdentry ? d_inode(upperdentry) : NULL;
@@ -994,7 +995,8 @@ struct inode *ovl_get_inode(struct super_block *sb,
 
 		/* Recalculate nlink for non-dir due to indexing */
 		if (!is_dir)
-			nlink = ovl_get_nlink(lowerdentry, upperdentry, nlink);
+			nlink = ovl_get_nlink(ofs, lowerdentry, upperdentry,
+					      nlink);
 		set_nlink(inode, nlink);
 		ino = key->i_ino;
 	} else {
@@ -1010,7 +1012,7 @@ struct inode *ovl_get_inode(struct super_block *sb,
 	ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev);
 	ovl_inode_init(inode, oip, ino, fsid);
 
-	if (upperdentry && ovl_is_impuredir(upperdentry))
+	if (upperdentry && ovl_is_impuredir(sb, upperdentry))
 		ovl_set_flag(OVL_IMPURE, inode);
 
 	if (oip->index)
@@ -1024,7 +1026,7 @@ struct inode *ovl_get_inode(struct super_block *sb,
 	/* Check for non-merge dir that may have whiteouts */
 	if (is_dir) {
 		if (((upperdentry && lowerdentry) || oip->numlower > 1) ||
-		    ovl_check_origin_xattr(upperdentry ?: lowerdentry)) {
+		    ovl_check_origin_xattr(ofs, upperdentry ?: lowerdentry)) {
 			ovl_set_flag(OVL_WHITEOUTS, inode);
 		}
 	}
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 18ccf7450603..56b8d3afa1f2 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -30,8 +30,9 @@ static int ovl_check_redirect(struct dentry *dentry, struct ovl_lookup_data *d,
 {
 	int res;
 	char *buf;
+	struct ovl_fs *ofs = OVL_FS(d->sb);
 
-	buf = ovl_get_redirect_xattr(dentry, prelen + strlen(post));
+	buf = ovl_get_redirect_xattr(ofs, dentry, prelen + strlen(post));
 	if (IS_ERR_OR_NULL(buf))
 		return PTR_ERR(buf);
 
@@ -104,12 +105,13 @@ int ovl_check_fb_len(struct ovl_fb *fb, int fb_len)
 	return 0;
 }
 
-static struct ovl_fh *ovl_get_fh(struct dentry *dentry, const char *name)
+static struct ovl_fh *ovl_get_fh(struct ovl_fs *ofs, struct dentry *dentry,
+				 const char *name)
 {
 	int res, err;
 	struct ovl_fh *fh = NULL;
 
-	res = ovl_do_getxattr(dentry, name, NULL, 0);
+	res = ovl_do_getxattr(ofs, dentry, name, NULL, 0);
 	if (res < 0) {
 		if (res == -ENODATA || res == -EOPNOTSUPP)
 			return NULL;
@@ -123,7 +125,7 @@ static struct ovl_fh *ovl_get_fh(struct dentry *dentry, const char *name)
 	if (!fh)
 		return ERR_PTR(-ENOMEM);
 
-	res = ovl_do_getxattr(dentry, name, fh->buf, res);
+	res = ovl_do_getxattr(ofs, dentry, name, fh->buf, res);
 	if (res < 0)
 		goto fail;
 
@@ -186,9 +188,9 @@ struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
 	return real;
 }
 
-static bool ovl_is_opaquedir(struct dentry *dentry)
+static bool ovl_is_opaquedir(struct super_block *sb, struct dentry *dentry)
 {
-	return ovl_check_dir_xattr(dentry, OVL_XATTR_OPAQUE);
+	return ovl_check_dir_xattr(sb, dentry, OVL_XATTR_OPAQUE);
 }
 
 static struct dentry *ovl_lookup_positive_unlocked(const char *name,
@@ -251,7 +253,7 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
 			d->stop = true;
 			goto put_and_out;
 		}
-		err = ovl_check_metacopy_xattr(this);
+		err = ovl_check_metacopy_xattr(OVL_FS(d->sb), this);
 		if (err < 0)
 			goto out_err;
 
@@ -271,7 +273,7 @@ static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d,
 		if (d->last)
 			goto out;
 
-		if (ovl_is_opaquedir(this)) {
+		if (ovl_is_opaquedir(d->sb, this)) {
 			d->stop = true;
 			if (last_element)
 				d->opaque = true;
@@ -391,7 +393,7 @@ invalid:
 static int ovl_check_origin(struct ovl_fs *ofs, struct dentry *upperdentry,
 			    struct ovl_path **stackp)
 {
-	struct ovl_fh *fh = ovl_get_fh(upperdentry, OVL_XATTR_ORIGIN);
+	struct ovl_fh *fh = ovl_get_fh(ofs, upperdentry, OVL_XATTR_ORIGIN);
 	int err;
 
 	if (IS_ERR_OR_NULL(fh))
@@ -413,10 +415,10 @@ static int ovl_check_origin(struct ovl_fs *ofs, struct dentry *upperdentry,
  * Verify that @fh matches the file handle stored in xattr @name.
  * Return 0 on match, -ESTALE on mismatch, < 0 on error.
  */
-static int ovl_verify_fh(struct dentry *dentry, const char *name,
-			 const struct ovl_fh *fh)
+static int ovl_verify_fh(struct ovl_fs *ofs, struct dentry *dentry,
+			 const char *name, const struct ovl_fh *fh)
 {
-	struct ovl_fh *ofh = ovl_get_fh(dentry, name);
+	struct ovl_fh *ofh = ovl_get_fh(ofs, dentry, name);
 	int err = 0;
 
 	if (!ofh)
@@ -440,8 +442,9 @@ static int ovl_verify_fh(struct dentry *dentry, const char *name,
  *
  * Return 0 on match, -ESTALE on mismatch, -ENODATA on no xattr, < 0 on error.
  */
-int ovl_verify_set_fh(struct dentry *dentry, const char *name,
-		      struct dentry *real, bool is_upper, bool set)
+int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
+		      const char *name, struct dentry *real, bool is_upper,
+		      bool set)
 {
 	struct inode *inode;
 	struct ovl_fh *fh;
@@ -454,9 +457,9 @@ int ovl_verify_set_fh(struct dentry *dentry, const char *name,
 		goto fail;
 	}
 
-	err = ovl_verify_fh(dentry, name, fh);
+	err = ovl_verify_fh(ofs, dentry, name, fh);
 	if (set && err == -ENODATA)
-		err = ovl_do_setxattr(dentry, name, fh->buf, fh->fb.len);
+		err = ovl_do_setxattr(ofs, dentry, name, fh->buf, fh->fb.len);
 	if (err)
 		goto fail;
 
@@ -481,7 +484,7 @@ struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index)
 	if (!d_is_dir(index))
 		return dget(index);
 
-	fh = ovl_get_fh(index, OVL_XATTR_UPPER);
+	fh = ovl_get_fh(ofs, index, OVL_XATTR_UPPER);
 	if (IS_ERR_OR_NULL(fh))
 		return ERR_CAST(fh);
 
@@ -574,7 +577,7 @@ int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index)
 		goto fail;
 	}
 
-	err = ovl_verify_fh(upper, OVL_XATTR_ORIGIN, fh);
+	err = ovl_verify_fh(ofs, upper, OVL_XATTR_ORIGIN, fh);
 	dput(upper);
 	if (err)
 		goto fail;
@@ -585,7 +588,7 @@ int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index)
 		if (err)
 			goto fail;
 
-		if (ovl_get_nlink(origin.dentry, index, 0) == 0)
+		if (ovl_get_nlink(ofs, origin.dentry, index, 0) == 0)
 			goto orphan;
 	}
 
@@ -741,7 +744,7 @@ struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
 		}
 
 		/* Verify that dir index 'upper' xattr points to upper dir */
-		err = ovl_verify_upper(index, upper, false);
+		err = ovl_verify_upper(ofs, index, upper, false);
 		if (err) {
 			if (err == -ESTALE) {
 				pr_warn_ratelimited("suspected multiply redirected dir found (upper=%pd2, origin=%pd2, index=%pd2).\n",
@@ -790,12 +793,12 @@ int ovl_path_next(int idx, struct dentry *dentry, struct path *path)
 }
 
 /* Fix missing 'origin' xattr */
-static int ovl_fix_origin(struct dentry *dentry, struct dentry *lower,
-			  struct dentry *upper)
+static int ovl_fix_origin(struct ovl_fs *ofs, struct dentry *dentry,
+			  struct dentry *lower, struct dentry *upper)
 {
 	int err;
 
-	if (ovl_check_origin_xattr(upper))
+	if (ovl_check_origin_xattr(ofs, upper))
 		return 0;
 
 	err = ovl_want_write(dentry);
@@ -920,7 +923,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 		 * of lower dir and set upper parent "impure".
 		 */
 		if (upperdentry && !ctr && !ofs->noxattr && d.is_dir) {
-			err = ovl_fix_origin(dentry, this, upperdentry);
+			err = ovl_fix_origin(ofs, dentry, this, upperdentry);
 			if (err) {
 				dput(this);
 				goto out_put;
@@ -939,7 +942,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 		if (upperdentry && !ctr &&
 		    ((d.is_dir && ovl_verify_lower(dentry->d_sb)) ||
 		     (!d.is_dir && ofs->config.index && origin_path))) {
-			err = ovl_verify_origin(upperdentry, this, false);
+			err = ovl_verify_origin(ofs, upperdentry, this, false);
 			if (err) {
 				dput(this);
 				if (d.is_dir)
@@ -1060,13 +1063,13 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 		ovl_dentry_set_upper_alias(dentry);
 	else if (index) {
 		upperdentry = dget(index);
-		upperredirect = ovl_get_redirect_xattr(upperdentry, 0);
+		upperredirect = ovl_get_redirect_xattr(ofs, upperdentry, 0);
 		if (IS_ERR(upperredirect)) {
 			err = PTR_ERR(upperredirect);
 			upperredirect = NULL;
 			goto out_free_oe;
 		}
-		err = ovl_check_metacopy_xattr(upperdentry);
+		err = ovl_check_metacopy_xattr(ofs, upperdentry);
 		if (err < 0)
 			goto out_free_oe;
 		uppermetacopy = err;
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 5f108233f03b..feef0eadc5b3 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -170,14 +170,16 @@ static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
 	return err;
 }
 
-static inline ssize_t ovl_do_getxattr(struct dentry *dentry, const char *name,
-				      void *value, size_t size)
+static inline ssize_t ovl_do_getxattr(struct ovl_fs *ofs, struct dentry *dentry,
+				      const char *name, void *value,
+				      size_t size)
 {
 	return vfs_getxattr(dentry, name, value, size);
 }
 
-static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
-				  const void *value, size_t size)
+static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
+				  const char *name, const void *value,
+				  size_t size)
 {
 	int err = vfs_setxattr(dentry, name, value, size, 0);
 	pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
@@ -185,7 +187,8 @@ static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
 	return err;
 }
 
-static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
+static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
+				     const char *name)
 {
 	int err = vfs_removexattr(dentry, name);
 	pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
@@ -286,8 +289,9 @@ struct file *ovl_path_open(struct path *path, int flags);
 int ovl_copy_up_start(struct dentry *dentry, int flags);
 void ovl_copy_up_end(struct dentry *dentry);
 bool ovl_already_copied_up(struct dentry *dentry, int flags);
-bool ovl_check_origin_xattr(struct dentry *dentry);
-bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
+bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry);
+bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry,
+			 const char *name);
 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
 		       const char *name, const void *value, size_t size,
 		       int xerr);
@@ -302,13 +306,15 @@ bool ovl_need_index(struct dentry *dentry);
 int ovl_nlink_start(struct dentry *dentry);
 void ovl_nlink_end(struct dentry *dentry);
 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
-int ovl_check_metacopy_xattr(struct dentry *dentry);
+int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry);
 bool ovl_is_metacopy_dentry(struct dentry *dentry);
-char *ovl_get_redirect_xattr(struct dentry *dentry, int padding);
+char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry,
+			     int padding);
 
-static inline bool ovl_is_impuredir(struct dentry *dentry)
+static inline bool ovl_is_impuredir(struct super_block *sb,
+				    struct dentry *dentry)
 {
-	return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE);
+	return ovl_check_dir_xattr(sb, dentry, OVL_XATTR_IMPURE);
 }
 
 /*
@@ -369,8 +375,9 @@ struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
 				  bool connected);
 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
 			struct dentry *upperdentry, struct ovl_path **stackp);
-int ovl_verify_set_fh(struct dentry *dentry, const char *name,
-		      struct dentry *real, bool is_upper, bool set);
+int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
+		      const char *name, struct dentry *real, bool is_upper,
+		      bool set);
 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
 int ovl_get_index_name(struct dentry *origin, struct qstr *name);
@@ -382,16 +389,17 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 			  unsigned int flags);
 bool ovl_lower_positive(struct dentry *dentry);
 
-static inline int ovl_verify_origin(struct dentry *upper,
+static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
 				    struct dentry *origin, bool set)
 {
-	return ovl_verify_set_fh(upper, OVL_XATTR_ORIGIN, origin, false, set);
+	return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin,
+				 false, set);
 }
 
-static inline int ovl_verify_upper(struct dentry *index,
-				    struct dentry *upper, bool set)
+static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
+				   struct dentry *upper, bool set)
 {
-	return ovl_verify_set_fh(index, OVL_XATTR_UPPER, upper, true, set);
+	return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set);
 }
 
 /* readdir.c */
@@ -408,7 +416,7 @@ int ovl_indexdir_cleanup(struct ovl_fs *ofs);
 /* inode.c */
 int ovl_set_nlink_upper(struct dentry *dentry);
 int ovl_set_nlink_lower(struct dentry *dentry);
-unsigned int ovl_get_nlink(struct dentry *lowerdentry,
+unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
 			   struct dentry *upperdentry,
 			   unsigned int fallback);
 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
@@ -422,7 +430,7 @@ int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
-bool ovl_is_private_xattr(const char *name);
+bool ovl_is_private_xattr(struct super_block *sb, const char *name);
 
 struct ovl_inode_params {
 	struct inode *newinode;
@@ -488,7 +496,8 @@ void ovl_aio_request_cache_destroy(void);
 int ovl_copy_up(struct dentry *dentry);
 int ovl_copy_up_with_data(struct dentry *dentry);
 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
-int ovl_copy_xattr(struct dentry *old, struct dentry *new);
+int ovl_copy_xattr(struct super_block *sb, struct dentry *old,
+		   struct dentry *new);
 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
 struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper);
 int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index f8cc15533afa..596002054ac6 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -606,6 +606,7 @@ static struct ovl_dir_cache *ovl_cache_get_impure(struct path *path)
 {
 	int res;
 	struct dentry *dentry = path->dentry;
+	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
 	struct ovl_dir_cache *cache;
 
 	cache = ovl_dir_cache(d_inode(dentry));
@@ -632,7 +633,7 @@ static struct ovl_dir_cache *ovl_cache_get_impure(struct path *path)
 		 * Removing the "impure" xattr is best effort.
 		 */
 		if (!ovl_want_write(dentry)) {
-			ovl_do_removexattr(ovl_dentry_upper(dentry),
+			ovl_do_removexattr(ofs, ovl_dentry_upper(dentry),
 					   OVL_XATTR_IMPURE);
 			ovl_drop_write(dentry);
 		}
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index fcfb32aaca9a..290983bcfbb3 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1319,7 +1319,7 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 	/*
 	 * Check if upper/work fs supports trusted.overlay.* xattr
 	 */
-	err = ovl_do_setxattr(ofs->workdir, OVL_XATTR_OPAQUE, "0", 1);
+	err = ovl_do_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1);
 	if (err) {
 		ofs->noxattr = true;
 		ofs->config.index = false;
@@ -1327,7 +1327,7 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 		pr_warn("upper fs does not support xattr, falling back to index=off and metacopy=off.\n");
 		err = 0;
 	} else {
-		ovl_do_removexattr(ofs->workdir, OVL_XATTR_OPAQUE);
+		ovl_do_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE);
 	}
 
 	/*
@@ -1430,8 +1430,8 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
 		return err;
 
 	/* Verify lower root is upper root origin */
-	err = ovl_verify_origin(upperpath->dentry, oe->lowerstack[0].dentry,
-				true);
+	err = ovl_verify_origin(ofs, upperpath->dentry,
+				oe->lowerstack[0].dentry, true);
 	if (err) {
 		pr_err("failed to verify upper root origin\n");
 		goto out;
@@ -1462,13 +1462,15 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
 		 * "trusted.overlay.upper" to indicate that index may have
 		 * directory entries.
 		 */
-		if (ovl_check_origin_xattr(ofs->indexdir)) {
-			err = ovl_verify_set_fh(ofs->indexdir, OVL_XATTR_ORIGIN,
+		if (ovl_check_origin_xattr(ofs, ofs->indexdir)) {
+			err = ovl_verify_set_fh(ofs, ofs->indexdir,
+						OVL_XATTR_ORIGIN,
 						upperpath->dentry, true, false);
 			if (err)
 				pr_err("failed to verify index dir 'origin' xattr\n");
 		}
-		err = ovl_verify_upper(ofs->indexdir, upperpath->dentry, true);
+		err = ovl_verify_upper(ofs, ofs->indexdir, upperpath->dentry,
+				       true);
 		if (err)
 			pr_err("failed to verify index dir 'upper' xattr\n");
 
@@ -1834,7 +1836,7 @@ static struct dentry *ovl_get_root(struct super_block *sb,
 		ino = d_inode(upperdentry)->i_ino;
 		fsid = 0;
 		ovl_dentry_set_upper_alias(root);
-		if (ovl_is_impuredir(upperdentry))
+		if (ovl_is_impuredir(sb, upperdentry))
 			ovl_set_flag(OVL_IMPURE, d_inode(root));
 	}
 
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 7d86dba0db68..17bfc19625d0 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -544,11 +544,11 @@ void ovl_copy_up_end(struct dentry *dentry)
 	ovl_inode_unlock(d_inode(dentry));
 }
 
-bool ovl_check_origin_xattr(struct dentry *dentry)
+bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry)
 {
 	int res;
 
-	res = ovl_do_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0);
+	res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_ORIGIN, NULL, 0);
 
 	/* Zero size value means "copied up but origin unknown" */
 	if (res >= 0)
@@ -557,7 +557,8 @@ bool ovl_check_origin_xattr(struct dentry *dentry)
 	return false;
 }
 
-bool ovl_check_dir_xattr(struct dentry *dentry, const char *name)
+bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry,
+			 const char *name)
 {
 	int res;
 	char val;
@@ -565,7 +566,7 @@ bool ovl_check_dir_xattr(struct dentry *dentry, const char *name)
 	if (!d_is_dir(dentry))
 		return false;
 
-	res = ovl_do_getxattr(dentry, name, &val, 1);
+	res = ovl_do_getxattr(OVL_FS(sb), dentry, name, &val, 1);
 	if (res == 1 && val == 'y')
 		return true;
 
@@ -582,7 +583,7 @@ int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
 	if (ofs->noxattr)
 		return xerr;
 
-	err = ovl_do_setxattr(upperdentry, name, value, size);
+	err = ovl_do_setxattr(ofs, upperdentry, name, value, size);
 
 	if (err == -EOPNOTSUPP) {
 		pr_warn("cannot set %s xattr on upper\n", name);
@@ -845,7 +846,7 @@ err:
 }
 
 /* err < 0, 0 if no metacopy xattr, 1 if metacopy xattr found */
-int ovl_check_metacopy_xattr(struct dentry *dentry)
+int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry)
 {
 	int res;
 
@@ -853,7 +854,7 @@ int ovl_check_metacopy_xattr(struct dentry *dentry)
 	if (!S_ISREG(d_inode(dentry)->i_mode))
 		return 0;
 
-	res = ovl_do_getxattr(dentry, OVL_XATTR_METACOPY, NULL, 0);
+	res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_METACOPY, NULL, 0);
 	if (res < 0) {
 		if (res == -ENODATA || res == -EOPNOTSUPP)
 			return 0;
@@ -882,12 +883,13 @@ bool ovl_is_metacopy_dentry(struct dentry *dentry)
 	return (oe->numlower > 1);
 }
 
-char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
+char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry,
+			     int padding)
 {
 	int res;
 	char *s, *next, *buf = NULL;
 
-	res = ovl_do_getxattr(dentry, OVL_XATTR_REDIRECT, NULL, 0);
+	res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_REDIRECT, NULL, 0);
 	if (res == -ENODATA || res == -EOPNOTSUPP)
 		return NULL;
 	if (res < 0)
@@ -899,7 +901,7 @@ char *ovl_get_redirect_xattr(struct dentry *dentry, int padding)
 	if (!buf)
 		return ERR_PTR(-ENOMEM);
 
-	res = ovl_do_getxattr(dentry, OVL_XATTR_REDIRECT, buf, res);
+	res = ovl_do_getxattr(ofs, dentry, OVL_XATTR_REDIRECT, buf, res);
 	if (res < 0)
 		goto fail;
 	if (res == 0)

From 43d193f8440d67f0dddd93ae973eb94174039e83 Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@redhat.com>
Date: Wed, 2 Sep 2020 10:58:49 +0200
Subject: [PATCH 10/13] ovl: enumerate private xattrs

Instead of passing the xattr name down to the ovl_do_*xattr() accessor
functions, pass an enumerated value.  The enum can use the same names as
the the previous #define for each xattr name.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/namei.c     | 16 ++++++++--------
 fs/overlayfs/overlayfs.h | 38 +++++++++++++++++++++++++-------------
 fs/overlayfs/util.c      | 31 ++++++++++++++++++++++++++-----
 3 files changed, 59 insertions(+), 26 deletions(-)

diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 56b8d3afa1f2..a6162c4076db 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -106,12 +106,12 @@ int ovl_check_fb_len(struct ovl_fb *fb, int fb_len)
 }
 
 static struct ovl_fh *ovl_get_fh(struct ovl_fs *ofs, struct dentry *dentry,
-				 const char *name)
+				 enum ovl_xattr ox)
 {
 	int res, err;
 	struct ovl_fh *fh = NULL;
 
-	res = ovl_do_getxattr(ofs, dentry, name, NULL, 0);
+	res = ovl_do_getxattr(ofs, dentry, ox, NULL, 0);
 	if (res < 0) {
 		if (res == -ENODATA || res == -EOPNOTSUPP)
 			return NULL;
@@ -125,7 +125,7 @@ static struct ovl_fh *ovl_get_fh(struct ovl_fs *ofs, struct dentry *dentry,
 	if (!fh)
 		return ERR_PTR(-ENOMEM);
 
-	res = ovl_do_getxattr(ofs, dentry, name, fh->buf, res);
+	res = ovl_do_getxattr(ofs, dentry, ox, fh->buf, res);
 	if (res < 0)
 		goto fail;
 
@@ -416,9 +416,9 @@ static int ovl_check_origin(struct ovl_fs *ofs, struct dentry *upperdentry,
  * Return 0 on match, -ESTALE on mismatch, < 0 on error.
  */
 static int ovl_verify_fh(struct ovl_fs *ofs, struct dentry *dentry,
-			 const char *name, const struct ovl_fh *fh)
+			 enum ovl_xattr ox, const struct ovl_fh *fh)
 {
-	struct ovl_fh *ofh = ovl_get_fh(ofs, dentry, name);
+	struct ovl_fh *ofh = ovl_get_fh(ofs, dentry, ox);
 	int err = 0;
 
 	if (!ofh)
@@ -443,7 +443,7 @@ static int ovl_verify_fh(struct ovl_fs *ofs, struct dentry *dentry,
  * Return 0 on match, -ESTALE on mismatch, -ENODATA on no xattr, < 0 on error.
  */
 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
-		      const char *name, struct dentry *real, bool is_upper,
+		      enum ovl_xattr ox, struct dentry *real, bool is_upper,
 		      bool set)
 {
 	struct inode *inode;
@@ -457,9 +457,9 @@ int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
 		goto fail;
 	}
 
-	err = ovl_verify_fh(ofs, dentry, name, fh);
+	err = ovl_verify_fh(ofs, dentry, ox, fh);
 	if (set && err == -ENODATA)
-		err = ovl_do_setxattr(ofs, dentry, name, fh->buf, fh->fb.len);
+		err = ovl_do_setxattr(ofs, dentry, ox, fh->buf, fh->fb.len);
 	if (err)
 		goto fail;
 
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index feef0eadc5b3..7bce2469fe55 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -23,13 +23,16 @@ enum ovl_path_type {
 #define OVL_TYPE_ORIGIN(type)	((type) & __OVL_PATH_ORIGIN)
 
 #define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay."
-#define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque"
-#define OVL_XATTR_REDIRECT OVL_XATTR_PREFIX "redirect"
-#define OVL_XATTR_ORIGIN OVL_XATTR_PREFIX "origin"
-#define OVL_XATTR_IMPURE OVL_XATTR_PREFIX "impure"
-#define OVL_XATTR_NLINK OVL_XATTR_PREFIX "nlink"
-#define OVL_XATTR_UPPER OVL_XATTR_PREFIX "upper"
-#define OVL_XATTR_METACOPY OVL_XATTR_PREFIX "metacopy"
+
+enum ovl_xattr {
+	OVL_XATTR_OPAQUE,
+	OVL_XATTR_REDIRECT,
+	OVL_XATTR_ORIGIN,
+	OVL_XATTR_IMPURE,
+	OVL_XATTR_NLINK,
+	OVL_XATTR_UPPER,
+	OVL_XATTR_METACOPY,
+};
 
 enum ovl_inode_flag {
 	/* Pure upper dir that may contain non pure upper entries */
@@ -110,6 +113,12 @@ struct ovl_fh {
 #define OVL_FH_FID_OFFSET	(OVL_FH_WIRE_OFFSET + \
 				 offsetof(struct ovl_fb, fid))
 
+extern const char *ovl_xattr_table[];
+static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
+{
+	return ovl_xattr_table[ox];
+}
+
 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
 {
 	int err = vfs_rmdir(dir, dentry);
@@ -171,16 +180,18 @@ static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
 }
 
 static inline ssize_t ovl_do_getxattr(struct ovl_fs *ofs, struct dentry *dentry,
-				      const char *name, void *value,
+				      enum ovl_xattr ox, void *value,
 				      size_t size)
 {
+	const char *name = ovl_xattr(ofs, ox);
 	return vfs_getxattr(dentry, name, value, size);
 }
 
 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
-				  const char *name, const void *value,
+				  enum ovl_xattr ox, const void *value,
 				  size_t size)
 {
+	const char *name = ovl_xattr(ofs, ox);
 	int err = vfs_setxattr(dentry, name, value, size, 0);
 	pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
 		 dentry, name, min((int)size, 48), value, size, err);
@@ -188,8 +199,9 @@ static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
 }
 
 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
-				     const char *name)
+				     enum ovl_xattr ox)
 {
+	const char *name = ovl_xattr(ofs, ox);
 	int err = vfs_removexattr(dentry, name);
 	pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
 	return err;
@@ -291,9 +303,9 @@ void ovl_copy_up_end(struct dentry *dentry);
 bool ovl_already_copied_up(struct dentry *dentry, int flags);
 bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry);
 bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry,
-			 const char *name);
+			 enum ovl_xattr ox);
 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
-		       const char *name, const void *value, size_t size,
+		       enum ovl_xattr ox, const void *value, size_t size,
 		       int xerr);
 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
 void ovl_set_flag(unsigned long flag, struct inode *inode);
@@ -376,7 +388,7 @@ struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
 			struct dentry *upperdentry, struct ovl_path **stackp);
 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
-		      const char *name, struct dentry *real, bool is_upper,
+		      enum ovl_xattr ox, struct dentry *real, bool is_upper,
 		      bool set);
 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 17bfc19625d0..23f475627d07 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -558,7 +558,7 @@ bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry)
 }
 
 bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry,
-			 const char *name)
+			 enum ovl_xattr ox)
 {
 	int res;
 	char val;
@@ -566,15 +566,36 @@ bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry,
 	if (!d_is_dir(dentry))
 		return false;
 
-	res = ovl_do_getxattr(OVL_FS(sb), dentry, name, &val, 1);
+	res = ovl_do_getxattr(OVL_FS(sb), dentry, ox, &val, 1);
 	if (res == 1 && val == 'y')
 		return true;
 
 	return false;
 }
 
+#define OVL_XATTR_OPAQUE_POSTFIX	"opaque"
+#define OVL_XATTR_REDIRECT_POSTFIX	"redirect"
+#define OVL_XATTR_ORIGIN_POSTFIX	"origin"
+#define OVL_XATTR_IMPURE_POSTFIX	"impure"
+#define OVL_XATTR_NLINK_POSTFIX		"nlink"
+#define OVL_XATTR_UPPER_POSTFIX		"upper"
+#define OVL_XATTR_METACOPY_POSTFIX	"metacopy"
+
+#define OVL_XATTR_TAB_ENTRY(x) \
+	[x] = OVL_XATTR_PREFIX x ## _POSTFIX
+
+const char *ovl_xattr_table[] = {
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_OPAQUE),
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_REDIRECT),
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_ORIGIN),
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_IMPURE),
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_NLINK),
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_UPPER),
+	OVL_XATTR_TAB_ENTRY(OVL_XATTR_METACOPY),
+};
+
 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
-		       const char *name, const void *value, size_t size,
+		       enum ovl_xattr ox, const void *value, size_t size,
 		       int xerr)
 {
 	int err;
@@ -583,10 +604,10 @@ int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
 	if (ofs->noxattr)
 		return xerr;
 
-	err = ovl_do_setxattr(ofs, upperdentry, name, value, size);
+	err = ovl_do_setxattr(ofs, upperdentry, ox, value, size);
 
 	if (err == -EOPNOTSUPP) {
-		pr_warn("cannot set %s xattr on upper\n", name);
+		pr_warn("cannot set %s xattr on upper\n", ovl_xattr(ofs, ox));
 		ofs->noxattr = true;
 		return xerr;
 	}

From 8f6ee74c27860d4a4c6e0f8cf772bb2afc184bcb Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <mszeredi@redhat.com>
Date: Wed, 2 Sep 2020 10:58:49 +0200
Subject: [PATCH 11/13] ovl: rearrange ovl_can_list()

ovl_can_list() should return false for overlay private xattrs.  Since
currently these use the "trusted.overlay." prefix, they will always match
the "trusted." prefix as well, hence the test for being non-trusted will
not trigger.

Prepare for using the "user.overlay." namespace by moving the test for
private xattr before the test for non-trusted.

This patch doesn't change behavior.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/inode.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 96666fe327de..b584dca845ba 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -393,13 +393,16 @@ int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
 
 static bool ovl_can_list(struct super_block *sb, const char *s)
 {
+	/* Never list private (.overlay) */
+	if (ovl_is_private_xattr(sb, s))
+		return false;
+
 	/* List all non-trusted xatts */
 	if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0)
 		return true;
 
-	/* Never list trusted.overlay, list other trusted for superuser only */
-	return !ovl_is_private_xattr(sb, s) &&
-	       ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN);
+	/* list other trusted for superuser only */
+	return ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN);
 }
 
 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)

From 61536bed2149b082748f8a38c593d915ff3e5957 Mon Sep 17 00:00:00 2001
From: Amir Goldstein <amir73il@gmail.com>
Date: Tue, 29 Sep 2020 15:28:47 +0800
Subject: [PATCH 12/13] ovl: support [S|G]ETFLAGS and FS[S|G]ETXATTR ioctls for
 directories

[S|G]ETFLAGS and FS[S|G]ETXATTR ioctls are applicable to both files and
directories, so add ioctl operations to dir as well.

We teach ovl_real_fdget() to get the realfile of directories which use
a different type of file->private_data.

Ifdef away compat ioctl implementation to conform to standard practice.

With this change, xfstest generic/079 which tests these ioctls on files
and directories passes.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/file.c      | 16 ++++++++++++---
 fs/overlayfs/overlayfs.h |  3 +++
 fs/overlayfs/readdir.c   | 44 ++++++++++++++++++++++++++++++++--------
 3 files changed, 51 insertions(+), 12 deletions(-)

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 3582c3ae819c..443986ca564b 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -136,6 +136,13 @@ static int ovl_real_fdget_meta(const struct file *file, struct fd *real,
 
 static int ovl_real_fdget(const struct file *file, struct fd *real)
 {
+	if (d_is_dir(file_dentry(file))) {
+		real->flags = 0;
+		real->file = ovl_dir_real_file(file, false);
+
+		return PTR_ERR_OR_ZERO(real->file);
+	}
+
 	return ovl_real_fdget_meta(file, real, false);
 }
 
@@ -648,7 +655,7 @@ static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
 				   ovl_fsxflags_to_iflags(fa.fsx_xflags));
 }
 
-static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	long ret;
 
@@ -673,8 +680,8 @@ static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	return ret;
 }
 
-static long ovl_compat_ioctl(struct file *file, unsigned int cmd,
-			     unsigned long arg)
+#ifdef CONFIG_COMPAT
+long ovl_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	switch (cmd) {
 	case FS_IOC32_GETFLAGS:
@@ -691,6 +698,7 @@ static long ovl_compat_ioctl(struct file *file, unsigned int cmd,
 
 	return ovl_ioctl(file, cmd, arg);
 }
+#endif
 
 enum ovl_copyop {
 	OVL_COPY,
@@ -792,7 +800,9 @@ const struct file_operations ovl_file_operations = {
 	.fallocate	= ovl_fallocate,
 	.fadvise	= ovl_fadvise,
 	.unlocked_ioctl	= ovl_ioctl,
+#ifdef CONFIG_COMPAT
 	.compat_ioctl	= ovl_compat_ioctl,
+#endif
 	.splice_read    = ovl_splice_read,
 	.splice_write   = ovl_splice_write,
 
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 7bce2469fe55..f8880aa2ba0e 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -416,6 +416,7 @@ static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
 
 /* readdir.c */
 extern const struct file_operations ovl_dir_operations;
+struct file *ovl_dir_real_file(const struct file *file, bool want_upper);
 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
 void ovl_cache_free(struct list_head *list);
@@ -503,6 +504,8 @@ struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr);
 extern const struct file_operations ovl_file_operations;
 int __init ovl_aio_request_cache_init(void);
 void ovl_aio_request_cache_destroy(void);
+long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
+long ovl_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 
 /* copy_up.c */
 int ovl_copy_up(struct dentry *dentry);
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 596002054ac6..01620ebae1bd 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -840,7 +840,7 @@ out_unlock:
 	return res;
 }
 
-static struct file *ovl_dir_open_realfile(struct file *file,
+static struct file *ovl_dir_open_realfile(const struct file *file,
 					  struct path *realpath)
 {
 	struct file *res;
@@ -853,19 +853,22 @@ static struct file *ovl_dir_open_realfile(struct file *file,
 	return res;
 }
 
-static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
-			 int datasync)
+/*
+ * Like ovl_real_fdget(), returns upperfile if dir was copied up since open.
+ * Unlike ovl_real_fdget(), this caches upperfile in file->private_data.
+ *
+ * TODO: use same abstract type for file->private_data of dir and file so
+ * upperfile could also be cached for files as well.
+ */
+struct file *ovl_dir_real_file(const struct file *file, bool want_upper)
 {
+
 	struct ovl_dir_file *od = file->private_data;
 	struct dentry *dentry = file->f_path.dentry;
 	struct file *realfile = od->realfile;
 
-	/* Nothing to sync for lower */
 	if (!OVL_TYPE_UPPER(ovl_path_type(dentry)))
-		return 0;
-
-	if (!ovl_should_sync(OVL_FS(dentry->d_sb)))
-		return 0;
+		return want_upper ? NULL : realfile;
 
 	/*
 	 * Need to check if we started out being a lower dir, but got copied up
@@ -884,7 +887,7 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
 			if (!od->upperfile) {
 				if (IS_ERR(realfile)) {
 					inode_unlock(inode);
-					return PTR_ERR(realfile);
+					return realfile;
 				}
 				smp_store_release(&od->upperfile, realfile);
 			} else {
@@ -897,6 +900,25 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
 		}
 	}
 
+	return realfile;
+}
+
+static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
+			 int datasync)
+{
+	struct file *realfile;
+	int err;
+
+	if (!ovl_should_sync(OVL_FS(file->f_path.dentry->d_sb)))
+		return 0;
+
+	realfile = ovl_dir_real_file(file, true);
+	err = PTR_ERR_OR_ZERO(realfile);
+
+	/* Nothing to sync for lower */
+	if (!realfile || err)
+		return err;
+
 	return vfs_fsync_range(realfile, start, end, datasync);
 }
 
@@ -949,6 +971,10 @@ const struct file_operations ovl_dir_operations = {
 	.llseek		= ovl_dir_llseek,
 	.fsync		= ovl_dir_fsync,
 	.release	= ovl_dir_release,
+	.unlocked_ioctl	= ovl_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ovl_compat_ioctl,
+#endif
 };
 
 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list)

From be4df0cea08a8b59eb38d73de988b7ba8022df41 Mon Sep 17 00:00:00 2001
From: Amir Goldstein <amir73il@gmail.com>
Date: Tue, 29 Sep 2020 15:28:48 +0800
Subject: [PATCH 13/13] ovl: use generic vfs_ioc_setflags_prepare() helper

Canonalize to ioctl FS_* flags instead of inode S_* flags.

Note that we do not call the helper vfs_ioc_fssetxattr_check()
for FS_IOC_FSSETXATTR ioctl. The reason is that underlying filesystem
will perform all the checks. We only need to perform the capability
check before overriding credentials.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/file.c | 62 ++++++++++++++++++++++-----------------------
 1 file changed, 30 insertions(+), 32 deletions(-)

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 443986ca564b..efccb7c1f9bc 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -559,12 +559,28 @@ static long ovl_real_ioctl(struct file *file, unsigned int cmd,
 	return ret;
 }
 
+static unsigned int ovl_iflags_to_fsflags(unsigned int iflags)
+{
+	unsigned int flags = 0;
+
+	if (iflags & S_SYNC)
+		flags |= FS_SYNC_FL;
+	if (iflags & S_APPEND)
+		flags |= FS_APPEND_FL;
+	if (iflags & S_IMMUTABLE)
+		flags |= FS_IMMUTABLE_FL;
+	if (iflags & S_NOATIME)
+		flags |= FS_NOATIME_FL;
+
+	return flags;
+}
+
 static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
-				unsigned long arg, unsigned int iflags)
+				unsigned long arg, unsigned int flags)
 {
 	long ret;
 	struct inode *inode = file_inode(file);
-	unsigned int old_iflags;
+	unsigned int oldflags;
 
 	if (!inode_owner_or_capable(inode))
 		return -EACCES;
@@ -576,10 +592,9 @@ static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
 	inode_lock(inode);
 
 	/* Check the capability before cred override */
-	ret = -EPERM;
-	old_iflags = READ_ONCE(inode->i_flags);
-	if (((iflags ^ old_iflags) & (S_APPEND | S_IMMUTABLE)) &&
-	    !capable(CAP_LINUX_IMMUTABLE))
+	oldflags = ovl_iflags_to_fsflags(READ_ONCE(inode->i_flags));
+	ret = vfs_ioc_setflags_prepare(inode, oldflags, flags);
+	if (ret)
 		goto unlock;
 
 	ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY);
@@ -598,22 +613,6 @@ unlock:
 
 }
 
-static unsigned int ovl_fsflags_to_iflags(unsigned int flags)
-{
-	unsigned int iflags = 0;
-
-	if (flags & FS_SYNC_FL)
-		iflags |= S_SYNC;
-	if (flags & FS_APPEND_FL)
-		iflags |= S_APPEND;
-	if (flags & FS_IMMUTABLE_FL)
-		iflags |= S_IMMUTABLE;
-	if (flags & FS_NOATIME_FL)
-		iflags |= S_NOATIME;
-
-	return iflags;
-}
-
 static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd,
 				  unsigned long arg)
 {
@@ -622,24 +621,23 @@ static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd,
 	if (get_user(flags, (int __user *) arg))
 		return -EFAULT;
 
-	return ovl_ioctl_set_flags(file, cmd, arg,
-				   ovl_fsflags_to_iflags(flags));
+	return ovl_ioctl_set_flags(file, cmd, arg, flags);
 }
 
-static unsigned int ovl_fsxflags_to_iflags(unsigned int xflags)
+static unsigned int ovl_fsxflags_to_fsflags(unsigned int xflags)
 {
-	unsigned int iflags = 0;
+	unsigned int flags = 0;
 
 	if (xflags & FS_XFLAG_SYNC)
-		iflags |= S_SYNC;
+		flags |= FS_SYNC_FL;
 	if (xflags & FS_XFLAG_APPEND)
-		iflags |= S_APPEND;
+		flags |= FS_APPEND_FL;
 	if (xflags & FS_XFLAG_IMMUTABLE)
-		iflags |= S_IMMUTABLE;
+		flags |= FS_IMMUTABLE_FL;
 	if (xflags & FS_XFLAG_NOATIME)
-		iflags |= S_NOATIME;
+		flags |= FS_NOATIME_FL;
 
-	return iflags;
+	return flags;
 }
 
 static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
@@ -652,7 +650,7 @@ static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
 		return -EFAULT;
 
 	return ovl_ioctl_set_flags(file, cmd, arg,
-				   ovl_fsxflags_to_iflags(fa.fsx_xflags));
+				   ovl_fsxflags_to_fsflags(fa.fsx_xflags));
 }
 
 long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)