Linux 5.12 compat: idmapped mounts

In Linux 5.12, the filesystem API was modified to support ipmapped
mounts by adding a "struct user_namespace *" parameter to a number
functions and VFS handlers. This change adds the needed autoconf
macros to detect the new interfaces and updates the code appropriately.
This change does not add support for idmapped mounts, instead it
preserves the existing behavior by passing the initial user namespace
where needed.  A subsequent commit will be required to add support
for idmapped mounted.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Coleman Kane <ckane@colemankane.org>
Closes #11712
(cherry picked from commit e2a8296131)
Signed-off-by: Jonathon Fernyhough <jonathon@m2x.dev>

module/os/linux/zfs/policy.c

@@ -124,7 +124,7 @@ secpolicy_vnode_any_access(const cred_t *cr, struct inode *ip, uid_t owner)
 	if (crgetfsuid(cr) == owner)
 		return (0);
 
-	if (inode_owner_or_capable(ip))
+	if (zpl_inode_owner_or_capable(kcred->user_ns, ip))
 		return (0);
 
 #if defined(CONFIG_USER_NS)

module/os/linux/zfs/zfs_vnops_os.c

@@ -1907,7 +1907,8 @@ out:
  */
 /* ARGSUSED */
 int
-zfs_getattr_fast(struct inode *ip, struct kstat *sp)
+zfs_getattr_fast(struct user_namespace *user_ns, struct inode *ip,
+    struct kstat *sp)
 {
 	znode_t *zp = ITOZ(ip);
 	zfsvfs_t *zfsvfs = ITOZSB(ip);
@@ -1919,7 +1920,7 @@ zfs_getattr_fast(struct inode *ip, struct kstat *sp)
 
 	mutex_enter(&zp->z_lock);
 
-	generic_fillattr(ip, sp);
+	zpl_generic_fillattr(user_ns, ip, sp);
 	/*
 	 * +1 link count for root inode with visible '.zfs' directory.
 	 */

module/os/linux/zfs/zpl_ctldir.c

@@ -101,12 +101,22 @@ zpl_root_readdir(struct file *filp, void *dirent, filldir_t filldir)
  */
 /* ARGSUSED */
 static int
+#ifdef HAVE_USERNS_IOPS_GETATTR
+zpl_root_getattr_impl(struct user_namespace *user_ns,
+    const struct path *path, struct kstat *stat, u32 request_mask,
+    unsigned int query_flags)
+#else
 zpl_root_getattr_impl(const struct path *path, struct kstat *stat,
     u32 request_mask, unsigned int query_flags)
+#endif
 {
 	struct inode *ip = path->dentry->d_inode;
 
+#if defined(HAVE_GENERIC_FILLATTR_USERNS) && defined(HAVE_USERNS_IOPS_GETATTR)
+	generic_fillattr(user_ns, ip, stat);
+#else
 	generic_fillattr(ip, stat);
+#endif
 	stat->atime = current_time(ip);
 
 	return (0);
@@ -290,8 +300,14 @@ zpl_snapdir_readdir(struct file *filp, void *dirent, filldir_t filldir)
 #endif /* !HAVE_VFS_ITERATE && !HAVE_VFS_ITERATE_SHARED */
 
 static int
+#ifdef HAVE_IOPS_RENAME_USERNS
+zpl_snapdir_rename2(struct user_namespace *user_ns, struct inode *sdip,
+    struct dentry *sdentry, struct inode *tdip, struct dentry *tdentry,
+    unsigned int flags)
+#else
 zpl_snapdir_rename2(struct inode *sdip, struct dentry *sdentry,
     struct inode *tdip, struct dentry *tdentry, unsigned int flags)
+#endif
 {
 	cred_t *cr = CRED();
 	int error;
@@ -309,7 +325,7 @@ zpl_snapdir_rename2(struct inode *sdip, struct dentry *sdentry,
 	return (error);
 }
 
-#ifndef HAVE_RENAME_WANTS_FLAGS
+#if !defined(HAVE_RENAME_WANTS_FLAGS) && !defined(HAVE_IOPS_RENAME_USERNS)
 static int
 zpl_snapdir_rename(struct inode *sdip, struct dentry *sdentry,
     struct inode *tdip, struct dentry *tdentry)
@@ -333,7 +349,12 @@ zpl_snapdir_rmdir(struct inode *dip, struct dentry *dentry)
 }
 
 static int
+#ifdef HAVE_IOPS_MKDIR_USERNS
+zpl_snapdir_mkdir(struct user_namespace *user_ns, struct inode *dip,
+    struct dentry *dentry, umode_t mode)
+#else
 zpl_snapdir_mkdir(struct inode *dip, struct dentry *dentry, umode_t mode)
+#endif
 {
 	cred_t *cr = CRED();
 	vattr_t *vap;
@@ -363,14 +384,24 @@ zpl_snapdir_mkdir(struct inode *dip, struct dentry *dentry, umode_t mode)
  */
 /* ARGSUSED */
 static int
+#ifdef HAVE_USERNS_IOPS_GETATTR
+zpl_snapdir_getattr_impl(struct user_namespace *user_ns,
+    const struct path *path, struct kstat *stat, u32 request_mask,
+    unsigned int query_flags)
+#else
 zpl_snapdir_getattr_impl(const struct path *path, struct kstat *stat,
     u32 request_mask, unsigned int query_flags)
+#endif
 {
 	struct inode *ip = path->dentry->d_inode;
 	zfsvfs_t *zfsvfs = ITOZSB(ip);
 
 	ZPL_ENTER(zfsvfs);
+#if defined(HAVE_GENERIC_FILLATTR_USERNS) && defined(HAVE_USERNS_IOPS_GETATTR)
+	generic_fillattr(user_ns, ip, stat);
+#else
 	generic_fillattr(ip, stat);
+#endif
 
 	stat->nlink = stat->size = 2;
 	stat->ctime = stat->mtime = dmu_objset_snap_cmtime(zfsvfs->z_os);
@@ -408,7 +439,7 @@ const struct file_operations zpl_fops_snapdir = {
 const struct inode_operations zpl_ops_snapdir = {
 	.lookup		= zpl_snapdir_lookup,
 	.getattr	= zpl_snapdir_getattr,
-#ifdef HAVE_RENAME_WANTS_FLAGS
+#if defined(HAVE_RENAME_WANTS_FLAGS) || defined(HAVE_IOPS_RENAME_USERNS)
 	.rename		= zpl_snapdir_rename2,
 #else
 	.rename		= zpl_snapdir_rename,
@@ -495,8 +526,14 @@ zpl_shares_readdir(struct file *filp, void *dirent, filldir_t filldir)
 
 /* ARGSUSED */
 static int
+#ifdef HAVE_USERNS_IOPS_GETATTR
+zpl_shares_getattr_impl(struct user_namespace *user_ns,
+    const struct path *path, struct kstat *stat, u32 request_mask,
+    unsigned int query_flags)
+#else
 zpl_shares_getattr_impl(const struct path *path, struct kstat *stat,
     u32 request_mask, unsigned int query_flags)
+#endif
 {
 	struct inode *ip = path->dentry->d_inode;
 	zfsvfs_t *zfsvfs = ITOZSB(ip);
@@ -506,7 +543,11 @@ zpl_shares_getattr_impl(const struct path *path, struct kstat *stat,
 	ZPL_ENTER(zfsvfs);
 
 	if (zfsvfs->z_shares_dir == 0) {
+#if defined(HAVE_GENERIC_FILLATTR_USERNS) && defined(HAVE_USERNS_IOPS_GETATTR)
+		generic_fillattr(user_ns, path->dentry->d_inode, stat);
+#else
 		generic_fillattr(path->dentry->d_inode, stat);
+#endif
 		stat->nlink = stat->size = 2;
 		stat->atime = current_time(ip);
 		ZPL_EXIT(zfsvfs);
@@ -515,7 +556,11 @@ zpl_shares_getattr_impl(const struct path *path, struct kstat *stat,
 
 	error = -zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp);
 	if (error == 0) {
-		error = -zfs_getattr_fast(ZTOI(dzp), stat);
+#if defined(HAVE_GENERIC_FILLATTR_USERNS) && defined(HAVE_USERNS_IOPS_GETATTR)
+		error = -zfs_getattr_fast(user_ns, ZTOI(dzp), stat);
+#else
+		error = -zfs_getattr_fast(kcred->user_ns, ZTOI(dzp), stat);
+#endif
 		iput(ZTOI(dzp));
 	}
 

module/os/linux/zfs/zpl_file.c

@@ -869,7 +869,7 @@ __zpl_ioctl_setflags(struct inode *ip, uint32_t ioctl_flags, xvattr_t *xva)
 	    !capable(CAP_LINUX_IMMUTABLE))
 		return (-EACCES);
 
-	if (!inode_owner_or_capable(ip))
+	if (!zpl_inode_owner_or_capable(kcred->user_ns, ip))
 		return (-EACCES);
 
 	xva_init(xva);

module/os/linux/zfs/zpl_inode.c

@@ -128,7 +128,12 @@ zpl_vap_init(vattr_t *vap, struct inode *dir, umode_t mode, cred_t *cr)
 }
 
 static int
+#ifdef HAVE_IOPS_CREATE_USERNS
+zpl_create(struct user_namespace *user_ns, struct inode *dir,
+    struct dentry *dentry, umode_t mode, bool flag)
+#else
 zpl_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool flag)
+#endif
 {
 	cred_t *cr = CRED();
 	znode_t *zp;
@@ -163,7 +168,12 @@ zpl_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool flag)
 }
 
 static int
+#ifdef HAVE_IOPS_MKNOD_USERNS
+zpl_mknod(struct user_namespace *user_ns, struct inode *dir,
+    struct dentry *dentry, umode_t mode,
+#else
 zpl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
+#endif
     dev_t rdev)
 {
 	cred_t *cr = CRED();
@@ -278,7 +288,12 @@ zpl_unlink(struct inode *dir, struct dentry *dentry)
 }
 
 static int
+#ifdef HAVE_IOPS_MKDIR_USERNS
+zpl_mkdir(struct user_namespace *user_ns, struct inode *dir,
+    struct dentry *dentry, umode_t mode)
+#else
 zpl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+#endif
 {
 	cred_t *cr = CRED();
 	vattr_t *vap;
@@ -338,8 +353,14 @@ zpl_rmdir(struct inode *dir, struct dentry *dentry)
 }
 
 static int
+#ifdef HAVE_USERNS_IOPS_GETATTR
+zpl_getattr_impl(struct user_namespace *user_ns,
+    const struct path *path, struct kstat *stat, u32 request_mask,
+    unsigned int query_flags)
+#else
 zpl_getattr_impl(const struct path *path, struct kstat *stat, u32 request_mask,
     unsigned int query_flags)
+#endif
 {
 	int error;
 	fstrans_cookie_t cookie;
@@ -350,7 +371,11 @@ zpl_getattr_impl(const struct path *path, struct kstat *stat, u32 request_mask,
 	 * XXX request_mask and query_flags currently ignored.
 	 */
 
-	error = -zfs_getattr_fast(path->dentry->d_inode, stat);
+#ifdef HAVE_USERNS_IOPS_GETATTR
+	error = -zfs_getattr_fast(user_ns, path->dentry->d_inode, stat);
+#else
+	error = -zfs_getattr_fast(kcred->user_ns, path->dentry->d_inode, stat);
+#endif
 	spl_fstrans_unmark(cookie);
 	ASSERT3S(error, <=, 0);
 
@@ -359,7 +384,12 @@ zpl_getattr_impl(const struct path *path, struct kstat *stat, u32 request_mask,
 ZPL_GETATTR_WRAPPER(zpl_getattr);
 
 static int
+#ifdef HAVE_SETATTR_PREPARE_USERNS
+zpl_setattr(struct user_namespace *user_ns, struct dentry *dentry,
+    struct iattr *ia)
+#else
 zpl_setattr(struct dentry *dentry, struct iattr *ia)
+#endif
 {
 	struct inode *ip = dentry->d_inode;
 	cred_t *cr = CRED();
@@ -367,7 +397,7 @@ zpl_setattr(struct dentry *dentry, struct iattr *ia)
 	int error;
 	fstrans_cookie_t cookie;
 
-	error = setattr_prepare(dentry, ia);
+	error = zpl_setattr_prepare(kcred->user_ns, dentry, ia);
 	if (error)
 		return (error);
 
@@ -399,8 +429,14 @@ zpl_setattr(struct dentry *dentry, struct iattr *ia)
 }
 
 static int
+#ifdef HAVE_IOPS_RENAME_USERNS
+zpl_rename2(struct user_namespace *user_ns, struct inode *sdip,
+    struct dentry *sdentry, struct inode *tdip, struct dentry *tdentry,
+    unsigned int flags)
+#else
 zpl_rename2(struct inode *sdip, struct dentry *sdentry,
     struct inode *tdip, struct dentry *tdentry, unsigned int flags)
+#endif
 {
 	cred_t *cr = CRED();
 	int error;
@@ -421,7 +457,7 @@ zpl_rename2(struct inode *sdip, struct dentry *sdentry,
 	return (error);
 }
 
-#ifndef HAVE_RENAME_WANTS_FLAGS
+#if !defined(HAVE_RENAME_WANTS_FLAGS) && !defined(HAVE_IOPS_RENAME_USERNS)
 static int
 zpl_rename(struct inode *sdip, struct dentry *sdentry,
     struct inode *tdip, struct dentry *tdentry)
@@ -431,7 +467,12 @@ zpl_rename(struct inode *sdip, struct dentry *sdentry,
 #endif
 
 static int
+#ifdef HAVE_IOPS_SYMLINK_USERNS
+zpl_symlink(struct user_namespace *user_ns, struct inode *dir,
+    struct dentry *dentry, const char *name)
+#else
 zpl_symlink(struct inode *dir, struct dentry *dentry, const char *name)
+#endif
 {
 	cred_t *cr = CRED();
 	vattr_t *vap;
@@ -677,7 +718,7 @@ const struct inode_operations zpl_dir_inode_operations = {
 	.mkdir		= zpl_mkdir,
 	.rmdir		= zpl_rmdir,
 	.mknod		= zpl_mknod,
-#ifdef HAVE_RENAME_WANTS_FLAGS
+#if defined(HAVE_RENAME_WANTS_FLAGS) || defined(HAVE_IOPS_RENAME_USERNS)
 	.rename		= zpl_rename2,
 #else
 	.rename		= zpl_rename,

module/os/linux/zfs/zpl_xattr.c

@@ -1233,7 +1233,7 @@ __zpl_xattr_acl_set_access(struct inode *ip, const char *name,
 	if (ITOZSB(ip)->z_acl_type != ZFS_ACLTYPE_POSIX)
 		return (-EOPNOTSUPP);
 
-	if (!inode_owner_or_capable(ip))
+	if (!zpl_inode_owner_or_capable(kcred->user_ns, ip))
 		return (-EPERM);
 
 	if (value) {
@@ -1273,7 +1273,7 @@ __zpl_xattr_acl_set_default(struct inode *ip, const char *name,
 	if (ITOZSB(ip)->z_acl_type != ZFS_ACLTYPE_POSIX)
 		return (-EOPNOTSUPP);
 
-	if (!inode_owner_or_capable(ip))
+	if (!zpl_inode_owner_or_capable(kcred->user_ns, ip))
 		return (-EPERM);
 
 	if (value) {