Linux 5.12: struct user_namespace* in fs operations arguments

config/kernel-generic_fillattr.m4

@@ -0,0 +1,28 @@
+dnl #
+dnl # 5.12 API
+dnl #
+dnl # generic_fillattr in linux/fs.h now requires a struct user_namespace*
+dnl # as the first arg, to support idmapped mounts.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_SRC_GENERIC_FILLATTR_USERNS], [
+	ZFS_LINUX_TEST_SRC([generic_fillattr_userns], [
+		#include <linux/fs.h>
+	],[
+		struct user_namespace *userns = NULL;
+		struct inode *in = NULL;
+		struct kstat *k = NULL;
+		generic_fillattr(userns, in, k);
+	])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_GENERIC_FILLATTR_USERNS], [
+	AC_MSG_CHECKING([whether generic_fillattr requres struct user_namespace*])
+	ZFS_LINUX_TEST_RESULT([generic_fillattr_userns], [
+		AC_MSG_RESULT([yes])
+		AC_DEFINE(HAVE_GENERIC_FILLATTR_USERNS, 1,
+		    [generic_fillattr requires struct user_namespace*])
+	],[
+		AC_MSG_RESULT([no])
+	])
+])
+

config/kernel-inode-create.m4

@@ -1,7 +1,25 @@
-dnl #
-dnl # 3.6 API change
-dnl #
-AC_DEFUN([ZFS_AC_KERNEL_SRC_CREATE_FLAGS], [
+AC_DEFUN([ZFS_AC_KERNEL_SRC_CREATE], [
+	dnl #
+	dnl # 5.12 API change that added the struct user_namespace* arg
+	dnl # to the front of this function type's arg list.
+	dnl #
+	ZFS_LINUX_TEST_SRC([create_userns], [
+		#include <linux/fs.h>
+		#include <linux/sched.h>
+
+		int inode_create(struct user_namespace *userns,
+		    struct inode *inode ,struct dentry *dentry,
+		    umode_t umode, bool flag) { return 0; }
+
+		static const struct inode_operations
+			iops __attribute__ ((unused)) = {
+			.create		= inode_create,
+		};
+	],[])
+
+	dnl #
+	dnl # 3.6 API change
+	dnl #
 	ZFS_LINUX_TEST_SRC([create_flags], [
 		#include <linux/fs.h>
 		#include <linux/sched.h>
@@ -16,11 +34,20 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_CREATE_FLAGS], [
 	],[])
 ])
 
-AC_DEFUN([ZFS_AC_KERNEL_CREATE_FLAGS], [
-	AC_MSG_CHECKING([whether iops->create() passes flags])
-	ZFS_LINUX_TEST_RESULT([create_flags], [
+AC_DEFUN([ZFS_AC_KERNEL_CREATE], [
+	AC_MSG_CHECKING([whether iops->create() takes struct user_namespace*])
+	ZFS_LINUX_TEST_RESULT([create_userns], [
 		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_IOPS_CREATE_USERNS, 1,
+		   [iops->create() takes struct user_namespace*])
 	],[
-		ZFS_LINUX_TEST_ERROR([iops->create()])
+		AC_MSG_RESULT(no)
+
+		AC_MSG_CHECKING([whether iops->create() passes flags])
+		ZFS_LINUX_TEST_RESULT([create_flags], [
+			AC_MSG_RESULT(yes)
+		],[
+			ZFS_LINUX_TEST_ERROR([iops->create()])
+		])
 	])
 ])

config/kernel-inode-getattr.m4

@@ -1,8 +1,29 @@
-dnl #
-dnl # Linux 4.11 API
-dnl # See torvalds/linux@a528d35
-dnl #
 AC_DEFUN([ZFS_AC_KERNEL_SRC_INODE_GETATTR], [
+	dnl #
+	dnl # Linux 5.12 API
+	dnl # The getattr I/O operations handler type was extended to require
+	dnl # a struct user_namespace* as its first arg, to support idmapped
+	dnl # mounts.
+	dnl #
+	ZFS_LINUX_TEST_SRC([inode_operations_getattr_userns], [
+		#include <linux/fs.h>
+
+		int test_getattr(
+			struct user_namespace *userns,
+		    const struct path *p, struct kstat *k,
+		    u32 request_mask, unsigned int query_flags)
+		    { return 0; }
+
+		static const struct inode_operations
+		    iops __attribute__ ((unused)) = {
+			.getattr = test_getattr,
+		};
+	],[])
+
+	dnl #
+	dnl # Linux 4.11 API
+	dnl # See torvalds/linux@a528d35
+	dnl #
 	ZFS_LINUX_TEST_SRC([inode_operations_getattr_path], [
 		#include <linux/fs.h>
 
@@ -33,21 +54,39 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_INODE_GETATTR], [
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_INODE_GETATTR], [
-	AC_MSG_CHECKING([whether iops->getattr() takes a path])
-	ZFS_LINUX_TEST_RESULT([inode_operations_getattr_path], [
+	dnl #
+	dnl # Kernel 5.12 test
+	dnl #
+	AC_MSG_CHECKING([whether iops->getattr() takes user_namespace])
+	ZFS_LINUX_TEST_RESULT([inode_operations_getattr_userns], [
 		AC_MSG_RESULT(yes)
-		AC_DEFINE(HAVE_PATH_IOPS_GETATTR, 1,
-		    [iops->getattr() takes a path])
+		AC_DEFINE(HAVE_USERNS_IOPS_GETATTR, 1,
+		    [iops->getattr() takes struct user_namespace*])
 	],[
 		AC_MSG_RESULT(no)
 
-		AC_MSG_CHECKING([whether iops->getattr() takes a vfsmount])
-		ZFS_LINUX_TEST_RESULT([inode_operations_getattr_vfsmount], [
+		dnl #
+		dnl # Kernel 4.11 test
+		dnl #
+		AC_MSG_CHECKING([whether iops->getattr() takes a path])
+		ZFS_LINUX_TEST_RESULT([inode_operations_getattr_path], [
 			AC_MSG_RESULT(yes)
-			AC_DEFINE(HAVE_VFSMOUNT_IOPS_GETATTR, 1,
-			    [iops->getattr() takes a vfsmount])
+			AC_DEFINE(HAVE_PATH_IOPS_GETATTR, 1,
+				[iops->getattr() takes a path])
 		],[
 			AC_MSG_RESULT(no)
+
+			dnl #
+			dnl # Kernel < 4.11 test
+			dnl #
+			AC_MSG_CHECKING([whether iops->getattr() takes a vfsmount])
+			ZFS_LINUX_TEST_RESULT([inode_operations_getattr_vfsmount], [
+				AC_MSG_RESULT(yes)
+				AC_DEFINE(HAVE_VFSMOUNT_IOPS_GETATTR, 1,
+					[iops->getattr() takes a vfsmount])
+			],[
+				AC_MSG_RESULT(no)
+			])
 		])
 	])
 ])

config/kernel-is_owner_or_cap.m4

@@ -11,13 +11,32 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_INODE_OWNER_OR_CAPABLE], [
 		struct inode *ip = NULL;
 		(void) inode_owner_or_capable(ip);
 	])
+
+	ZFS_LINUX_TEST_SRC([inode_owner_or_capable_idmapped], [
+		#include <linux/fs.h>
+	],[
+		struct inode *ip = NULL;
+		(void) inode_owner_or_capable(&init_user_ns, ip);
+	])
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_INODE_OWNER_OR_CAPABLE], [
 	AC_MSG_CHECKING([whether inode_owner_or_capable() exists])
 	ZFS_LINUX_TEST_RESULT([inode_owner_or_capable], [
 		AC_MSG_RESULT(yes)
-	],[
-		ZFS_LINUX_TEST_ERROR([capability])
+		AC_DEFINE(HAVE_INODE_OWNER_OR_CAPABLE, 1,
+		    [inode_owner_or_capable() exists])
+	], [
+		AC_MSG_RESULT(no)
+
+		AC_MSG_CHECKING(
+		    [whether inode_owner_or_capable() takes user_ns])
+		ZFS_LINUX_TEST_RESULT([inode_owner_or_capable_idmapped], [
+			AC_MSG_RESULT(yes)
+			AC_DEFINE(HAVE_INODE_OWNER_OR_CAPABLE_IDMAPPED, 1,
+			    [inode_owner_or_capable() takes user_ns])
+		],[
+			ZFS_LINUX_TEST_ERROR([capability])
+		])
 	])
 ])

config/kernel-mkdir.m4

@@ -0,0 +1,65 @@
+dnl #
+dnl # Supported mkdir() interfaces checked newest to oldest.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_SRC_MKDIR], [
+	dnl #
+	dnl # 5.12 API change
+	dnl # The struct user_namespace arg was added as the first argument to
+	dnl # mkdir()
+	dnl #
+	ZFS_LINUX_TEST_SRC([mkdir_user_namespace], [
+		#include <linux/fs.h>
+
+		int mkdir(struct user_namespace *userns,
+			struct inode *inode, struct dentry *dentry,
+		    umode_t umode) { return 0; }
+
+		static const struct inode_operations
+		    iops __attribute__ ((unused)) = {
+			.mkdir = mkdir,
+		};
+	],[])
+
+	dnl #
+	dnl # 3.3 API change
+	dnl # The VFS .create, .mkdir and .mknod callbacks were updated to take a
+	dnl # umode_t type rather than an int.  The expectation is that any backport
+	dnl # would also change all three prototypes.  However, if it turns out that
+	dnl # some distribution doesn't backport the whole thing this could be
+	dnl # broken apart into three separate checks.
+	dnl #
+	ZFS_LINUX_TEST_SRC([inode_operations_mkdir], [
+		#include <linux/fs.h>
+
+		int mkdir(struct inode *inode, struct dentry *dentry,
+		    umode_t umode) { return 0; }
+
+		static const struct inode_operations
+		    iops __attribute__ ((unused)) = {
+			.mkdir = mkdir,
+		};
+	],[])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_MKDIR], [
+	dnl #
+	dnl # 5.12 API change
+	dnl # The struct user_namespace arg was added as the first argument to
+	dnl # mkdir() of the iops structure.
+	dnl #
+	AC_MSG_CHECKING([whether iops->mkdir() takes struct user_namespace*])
+	ZFS_LINUX_TEST_RESULT([mkdir_user_namespace], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_IOPS_MKDIR_USERNS, 1,
+		    [iops->mkdir() takes struct user_namespace*])
+	],[
+		AC_MSG_CHECKING([whether iops->mkdir() takes umode_t])
+		ZFS_LINUX_TEST_RESULT([inode_operations_mkdir], [
+			AC_MSG_RESULT(yes)
+			AC_DEFINE(HAVE_MKDIR_UMODE_T, 1,
+			    [iops->mkdir() takes umode_t])
+		],[
+			ZFS_LINUX_TEST_ERROR([mkdir()])
+		])
+	])
+])

config/kernel-mknod.m4

@@ -0,0 +1,30 @@
+AC_DEFUN([ZFS_AC_KERNEL_SRC_MKNOD], [
+	dnl #
+	dnl # 5.12 API change that added the struct user_namespace* arg
+	dnl # to the front of this function type's arg list.
+	dnl #
+	ZFS_LINUX_TEST_SRC([mknod_userns], [
+		#include <linux/fs.h>
+		#include <linux/sched.h>
+
+		int tmp_mknod(struct user_namespace *userns,
+		    struct inode *inode ,struct dentry *dentry,
+		    umode_t u, dev_t d) { return 0; }
+
+		static const struct inode_operations
+			iops __attribute__ ((unused)) = {
+			.mknod		= tmp_mknod,
+		};
+	],[])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_MKNOD], [
+	AC_MSG_CHECKING([whether iops->mknod() takes struct user_namespace*])
+	ZFS_LINUX_TEST_RESULT([mknod_userns], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_IOPS_MKNOD_USERNS, 1,
+		    [iops->mknod() takes struct user_namespace*])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])

config/kernel-rename.m4

@@ -1,10 +1,10 @@
-dnl #
-dnl # 4.9 API change,
-dnl # iops->rename2() merged into iops->rename(), and iops->rename() now wants
-dnl # flags.
-dnl #
-AC_DEFUN([ZFS_AC_KERNEL_SRC_RENAME_WANTS_FLAGS], [
-	ZFS_LINUX_TEST_SRC([inode_operations_rename], [
+AC_DEFUN([ZFS_AC_KERNEL_SRC_RENAME], [
+	dnl #
+	dnl # 4.9 API change,
+	dnl # iops->rename2() merged into iops->rename(), and iops->rename() now wants
+	dnl # flags.
+	dnl #
+	ZFS_LINUX_TEST_SRC([inode_operations_rename_flags], [
 		#include <linux/fs.h>
 		int rename_fn(struct inode *sip, struct dentry *sdp,
 			struct inode *tip, struct dentry *tdp,
@@ -15,15 +15,41 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_RENAME_WANTS_FLAGS], [
 			.rename = rename_fn,
 		};
 	],[])
+
+	dnl #
+	dnl # 5.12 API change,
+	dnl #
+	dnl # Linux 5.12 introduced passing struct user_namespace* as the first argument
+	dnl # of the rename() and other inode_operations members.
+	dnl #
+	ZFS_LINUX_TEST_SRC([inode_operations_rename_userns], [
+		#include <linux/fs.h>
+		int rename_fn(struct user_namespace *user_ns, struct inode *sip,
+			struct dentry *sdp, struct inode *tip, struct dentry *tdp,
+			unsigned int flags) { return 0; }
+
+		static const struct inode_operations
+		    iops __attribute__ ((unused)) = {
+			.rename = rename_fn,
+		};
+	],[])
 ])
 
-AC_DEFUN([ZFS_AC_KERNEL_RENAME_WANTS_FLAGS], [
-	AC_MSG_CHECKING([whether iops->rename() wants flags])
-	ZFS_LINUX_TEST_RESULT([inode_operations_rename], [
+AC_DEFUN([ZFS_AC_KERNEL_RENAME], [
+	AC_MSG_CHECKING([whether iops->rename() takes struct user_namespace*])
+	ZFS_LINUX_TEST_RESULT([inode_operations_rename_userns], [
 		AC_MSG_RESULT(yes)
-		AC_DEFINE(HAVE_RENAME_WANTS_FLAGS, 1,
-		    [iops->rename() wants flags])
+		AC_DEFINE(HAVE_IOPS_RENAME_USERNS, 1,
+		    [iops->rename() takes struct user_namespace*])
 	],[
 		AC_MSG_RESULT(no)
+
+		ZFS_LINUX_TEST_RESULT([inode_operations_rename_flags], [
+			AC_MSG_RESULT(yes)
+			AC_DEFINE(HAVE_RENAME_WANTS_FLAGS, 1,
+				[iops->rename() wants flags])
+		],[
+			AC_MSG_RESULT(no)
+		])
 	])
 ])