[RFC PATCH 00/68] VFS: Convert a bunch of filesystems to the new mount API

Hi Al,

Here's a set of patches that converts a bunch (but not yet all!) to the new
mount API.  To this end, it makes the following changes:

 (1) Provides a convenience member in struct fs_context that is OR'd into
     sb->s_iflags by sget_fc().

 (2) Provides a convenience helper function, vfs_init_pseudo_fs_context(),
     for doing most of the work in mounting a pseudo filesystem.

 (3) Provides a convenience helper function, vfs_get_block_super(), for
     doing the work in setting up a block-based superblock.

 (4) Improves the handling of fd-type parameters.

 (5) Moves some of the subtype handling int fuse.

 (6) Provides a convenience helper function, vfs_get_mtd_super(), for
     doing the work in setting up an MTD device-based superblock.

 (7) Kills off mount_pseudo(), mount_pseudo_xattr(), mount_ns(),
     sget_userns(), mount_mtd(), mount_single().

 (8) Converts a slew of filesystems to use the mount API.

 (9) Fixes a bug in hypfs.

The patches can be found here also:

	https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git

on branch:

	mount-api-viro

David
---
Andrew Price (1):
      gfs2: Convert gfs2 to fs_context

David Howells (66):
      vfs: Update mount API docs
      vfs: Fix refcounting of filenames in fs_parser
      vfs: Provide sb->s_iflags settings in fs_context struct
      vfs: Provide a mount_pseudo-replacement for the new mount API
      vfs: Convert aio to use the new mount API
      vfs: Convert anon_inodes to use the new mount API
      vfs: Convert bdev to use the new mount API
      vfs: Convert nsfs to use the new mount API
      vfs: Convert pipe to use the new mount API
      vfs: Convert zsmalloc to use the new mount API
      vfs: Convert sockfs to use the new mount API
      vfs: Convert dax to use the new mount API
      vfs: Convert drm to use the new mount API
      vfs: Convert ia64 perfmon to use the new mount API
      vfs: Convert cxl to use the new mount API
      vfs: Convert ocxlflash to use the new mount API
      vfs: Convert virtio_balloon to use the new mount API
      vfs: Convert btrfs_test to use the new mount API
      vfs: Kill off mount_pseudo() and mount_pseudo_xattr()
      vfs: Use sget_fc() for pseudo-filesystems
      vfs: Convert binderfs to use the new mount API
      vfs: Convert nfsctl to use the new mount API
      vfs: Convert rpc_pipefs to use the new mount API
      vfs: Kill mount_ns()
      vfs: Kill sget_userns()
      vfs: Convert binfmt_misc to use the new mount API
      vfs: Convert configfs to use the new mount API
      vfs: Convert efivarfs to use the new mount API
      vfs: Convert fusectl to use the new mount API
      vfs: Convert qib_fs/ipathfs to use the new mount API
      vfs: Convert ibmasmfs to use the new mount API
      vfs: Convert oprofilefs to use the new mount API
      vfs: Convert gadgetfs to use the new mount API
      vfs: Convert xenfs to use the new mount API
      vfs: Convert openpromfs to use the new mount API
      vfs: Convert apparmorfs to use the new mount API
      vfs: Convert securityfs to use the new mount API
      vfs: Convert selinuxfs to use the new mount API
      vfs: Convert smackfs to use the new mount API
      vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API
      vfs: Create fs_context-aware mount_bdev() replacement
      vfs: Make fs_parse() handle fs_param_is_fd-type params better
      vfs: Convert fuse to use the new mount API
      vfs: Move the subtype parameter into fuse
      mtd: Provide fs_context-aware mount_mtd() replacement
      vfs: Convert romfs to use the new mount API
      vfs: Convert cramfs to use the new mount API
      vfs: Convert jffs2 to use the new mount API
      mtd: Kill mount_mtd()
      vfs: Convert squashfs to use the new mount API
      vfs: Convert ceph to use the new mount API
      vfs: Convert functionfs to use the new mount API
      vfs: Add a single-or-reconfig keying to vfs_get_super()
      vfs: Convert debugfs to use the new mount API
      vfs: Convert tracefs to use the new mount API
      vfs: Convert pstore to use the new mount API
      hypfs: Fix error number left in struct pointer member
      vfs: Convert hypfs to use the new mount API
      vfs: Convert spufs to use the new mount API
      vfs: Kill mount_single()
      vfs: Convert coda to use the new mount API
      vfs: Convert autofs to use the new mount API
      vfs: Convert devpts to use the new mount API
      vfs: Convert bpf to use the new mount API
      vfs: Convert ubifs to use the new mount API
      vfs: Convert orangefs to use the new mount API

Masahiro Yamada (1):
      kbuild: skip sub-make for in-tree build with GNU Make 4.x


 Documentation/filesystems/mount_api.txt   |  367 ++++++++-------
 Documentation/filesystems/vfs.txt         |    4 
 Makefile                                  |   31 +
 arch/ia64/kernel/perfmon.c                |   14 -
 arch/powerpc/platforms/cell/spufs/inode.c |  207 +++++----
 arch/s390/hypfs/inode.c                   |  137 +++---
 drivers/android/binderfs.c                |  173 ++++---
 drivers/base/devtmpfs.c                   |   16 -
 drivers/block/rbd.c                       |  363 ++++++++-------
 drivers/dax/super.c                       |   13 -
 drivers/gpu/drm/drm_drv.c                 |   14 -
 drivers/infiniband/hw/qib/qib_fs.c        |   26 +
 drivers/misc/cxl/api.c                    |   10 
 drivers/misc/ibmasm/ibmasmfs.c            |   21 +
 drivers/mtd/mtdcore.h                     |    1 
 drivers/mtd/mtdsuper.c                    |  181 ++++----
 drivers/oprofile/oprofilefs.c             |   20 +
 drivers/scsi/cxlflash/ocxl_hw.c           |   21 -
 drivers/usb/gadget/function/f_fs.c        |  233 +++++-----
 drivers/usb/gadget/legacy/inode.c         |   21 +
 drivers/virtio/virtio_balloon.c           |   19 -
 drivers/xen/xenfs/super.c                 |   21 +
 fs/aio.c                                  |   15 -
 fs/anon_inodes.c                          |   12 
 fs/autofs/autofs_i.h                      |   13 -
 fs/autofs/init.c                          |    9 
 fs/autofs/inode.c                         |  429 ++++++++++--------
 fs/binfmt_misc.c                          |   20 +
 fs/block_dev.c                            |   14 -
 fs/btrfs/tests/btrfs-tests.c              |   13 -
 fs/ceph/cache.c                           |    9 
 fs/ceph/cache.h                           |    5 
 fs/ceph/super.c                           |  697 ++++++++++++++---------------
 fs/ceph/super.h                           |    1 
 fs/coda/inode.c                           |  171 +++++--
 fs/configfs/mount.c                       |   20 +
 fs/cramfs/inode.c                         |   69 ++-
 fs/debugfs/inode.c                        |  186 ++++----
 fs/devpts/inode.c                         |  265 +++++------
 fs/efivarfs/super.c                       |   20 +
 fs/fs_context.c                           |   16 -
 fs/fs_parser.c                            |   18 +
 fs/fuse/control.c                         |   20 +
 fs/fuse/inode.c                           |  291 +++++++-----
 fs/gfs2/incore.h                          |    8 
 fs/gfs2/ops_fstype.c                      |  495 ++++++++++++++++-----
 fs/gfs2/super.c                           |  335 --------------
 fs/gfs2/super.h                           |    3 
 fs/jffs2/fs.c                             |   21 -
 fs/jffs2/os-linux.h                       |    4 
 fs/jffs2/super.c                          |  172 +++----
 fs/libfs.c                                |   91 +++-
 fs/nfsd/nfsctl.c                          |   33 +
 fs/nsfs.c                                 |   13 -
 fs/openpromfs/inode.c                     |   20 +
 fs/orangefs/orangefs-kernel.h             |    8 
 fs/orangefs/orangefs-mod.c                |    3 
 fs/orangefs/super.c                       |  186 ++++----
 fs/pipe.c                                 |   12 
 fs/pstore/inode.c                         |  109 +++--
 fs/ramfs/inode.c                          |  104 +++-
 fs/romfs/super.c                          |   46 +-
 fs/squashfs/super.c                       |  100 ++--
 fs/super.c                                |  301 ++++++-------
 fs/tracefs/inode.c                        |  180 +++----
 fs/ubifs/super.c                          |  447 ++++++++-----------
 include/linux/ceph/ceph_debug.h           |    1 
 include/linux/ceph/libceph.h              |   17 +
 include/linux/fs.h                        |   24 -
 include/linux/fs_context.h                |   20 +
 include/linux/mtd/super.h                 |    6 
 include/linux/ramfs.h                     |    6 
 include/linux/shmem_fs.h                  |    4 
 init/do_mounts.c                          |   12 
 kernel/bpf/inode.c                        |   92 ++--
 mm/shmem.c                                |  396 +++++++++++-----
 mm/zsmalloc.c                             |   19 -
 net/ceph/ceph_common.c                    |  410 +++++++----------
 net/socket.c                              |   14 -
 net/sunrpc/rpc_pipe.c                     |   34 +
 security/apparmor/apparmorfs.c            |   20 +
 security/inode.c                          |   21 +
 security/selinux/selinuxfs.c              |   20 +
 security/smack/smackfs.c                  |   34 +
 84 files changed, 4257 insertions(+), 3810 deletions(-)

Convert the cxl filesystem to the new internal mount API as the old
one will be obsoleted and removed.  This allows greater flexibility in
communication of mount parameters between userspace, the VFS and the
filesystem.

See Documentation/filesystems/mount_api.txt for more information.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Andrew Donnellan <redacted>
Acked-by: Frederic Barrat <redacted>
cc: linuxppc-dev@lists.ozlabs.org
---

 drivers/misc/cxl/api.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
index 750470ef2049..395e9a88e6ba 100644
--- a/drivers/misc/cxl/api.c
+++ b/drivers/misc/cxl/api.c

@@ -13,6 +13,7 @@
 #include <misc/cxl.h>
 #include <linux/module.h>
 #include <linux/mount.h>
+#include <linux/fs_context.h>
 #include <linux/sched/mm.h>
 #include <linux/mmu_context.h>
 

@@ -41,17 +42,16 @@ static const struct dentry_operations cxl_fs_dops = {
 	.d_dname	= simple_dname,
 };
 
-static struct dentry *cxl_fs_mount(struct file_system_type *fs_type, int flags,
-				const char *dev_name, void *data)
+static int cxl_fs_init_fs_context(struct fs_context *fc)
 {
-	return mount_pseudo(fs_type, "cxl:", NULL, &cxl_fs_dops,
-			CXL_PSEUDO_FS_MAGIC);
+	return vfs_init_pseudo_fs_context(fc, "cxl:", NULL, NULL,
+					  &cxl_fs_dops, CXL_PSEUDO_FS_MAGIC);
 }
 
 static struct file_system_type cxl_fs_type = {
 	.name		= "cxl",
 	.owner		= THIS_MODULE,
-	.mount		= cxl_fs_mount,
+	.init_fs_context = cxl_fs_init_fs_context,
 	.kill_sb	= kill_anon_super,
 };
 

Convert the spufs filesystem to the new internal mount API as the old
one will be obsoleted and removed.  This allows greater flexibility in
communication of mount parameters between userspace, the VFS and the
filesystem.

See Documentation/filesystems/mount_api.txt for more information.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeremy Kerr <jk@ozlabs.org>
cc: Arnd Bergmann <arnd@arndb.de>
cc: linuxppc-dev@lists.ozlabs.org
---

 arch/powerpc/platforms/cell/spufs/inode.c |  207 ++++++++++++++++-------------
 1 file changed, 116 insertions(+), 91 deletions(-)

diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c
index db329d4bf1c3..f951a7fe4e3c 100644
--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c

@@ -23,6 +23,8 @@
 
 #include <linux/file.h>
 #include <linux/fs.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
 #include <linux/fsnotify.h>
 #include <linux/backing-dev.h>
 #include <linux/init.h>

@@ -33,7 +35,6 @@
 #include <linux/pagemap.h>
 #include <linux/poll.h>
 #include <linux/slab.h>
-#include <linux/parser.h>
 
 #include <asm/prom.h>
 #include <asm/spu.h>

@@ -43,7 +44,7 @@
 #include "spufs.h"
 
 struct spufs_sb_info {
-	int debug;
+	bool debug;
 };
 
 static struct kmem_cache *spufs_inode_cache;

@@ -593,16 +594,27 @@ long spufs_create(struct path *path, struct dentry *dentry,
 }
 
 /* File system initialization */
+struct spufs_fs_context {
+	kuid_t	uid;
+	kgid_t	gid;
+	umode_t	mode;
+};
+
 enum {
-	Opt_uid, Opt_gid, Opt_mode, Opt_debug, Opt_err,
+	Opt_uid, Opt_gid, Opt_mode, Opt_debug,
+};
+
+static const struct fs_parameter_spec spufs_param_specs[] = {
+	fsparam_u32	("gid",				Opt_gid),
+	fsparam_u32oct	("mode",			Opt_mode),
+	fsparam_u32	("uid",				Opt_uid),
+	fsparam_flag	("debug",			Opt_debug),
+	{}
 };
 
-static const match_table_t spufs_tokens = {
-	{ Opt_uid,   "uid=%d" },
-	{ Opt_gid,   "gid=%d" },
-	{ Opt_mode,  "mode=%o" },
-	{ Opt_debug, "debug" },
-	{ Opt_err,    NULL  },
+static const struct fs_parameter_description spufs_fs_parameters = {
+	.name		= "spufs",
+	.specs		= spufs_param_specs,
 };
 
 static int spufs_show_options(struct seq_file *m, struct dentry *root)

@@ -623,47 +635,41 @@ static int spufs_show_options(struct seq_file *m, struct dentry *root)
 	return 0;
 }
 
-static int
-spufs_parse_options(struct super_block *sb, char *options, struct inode *root)
-{
-	char *p;
-	substring_t args[MAX_OPT_ARGS];
-
-	while ((p = strsep(&options, ",")) != NULL) {
-		int token, option;
-
-		if (!*p)
-			continue;
-
-		token = match_token(p, spufs_tokens, args);
-		switch (token) {
-		case Opt_uid:
-			if (match_int(&args[0], &option))
-				return 0;
-			root->i_uid = make_kuid(current_user_ns(), option);
-			if (!uid_valid(root->i_uid))
-				return 0;
-			break;
-		case Opt_gid:
-			if (match_int(&args[0], &option))
-				return 0;
-			root->i_gid = make_kgid(current_user_ns(), option);
-			if (!gid_valid(root->i_gid))
-				return 0;
-			break;
-		case Opt_mode:
-			if (match_octal(&args[0], &option))
-				return 0;
-			root->i_mode = option | S_IFDIR;
-			break;
-		case Opt_debug:
-			spufs_get_sb_info(sb)->debug = 1;
-			break;
-		default:
-			return 0;
-		}
+static int spufs_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct spufs_fs_context *ctx = fc->fs_private;
+	struct spufs_sb_info *sbi = fc->s_fs_info;
+	struct fs_parse_result result;
+	kuid_t uid;
+	kgid_t gid;
+	int opt;
+
+	opt = fs_parse(fc, &spufs_fs_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_uid:
+		uid = make_kuid(current_user_ns(), result.uint_32);
+		if (!uid_valid(uid))
+			return invalf(fc, "Unknown uid");
+		ctx->uid = uid;
+		break;
+	case Opt_gid:
+		gid = make_kgid(current_user_ns(), result.uint_32);
+		if (!gid_valid(gid))
+			return invalf(fc, "Unknown gid");
+		ctx->gid = gid;
+		break;
+	case Opt_mode:
+		ctx->mode = result.uint_32 & S_IALLUGO;
+		break;
+	case Opt_debug:
+		sbi->debug = true;
+		break;
 	}
-	return 1;
+
+	return 0;
 }
 
 static void spufs_exit_isolated_loader(void)

@@ -697,79 +703,98 @@ spufs_init_isolated_loader(void)
 	printk(KERN_INFO "spufs: SPU isolation mode enabled\n");
 }
 
-static int
-spufs_create_root(struct super_block *sb, void *data)
+static int spufs_create_root(struct super_block *sb, struct fs_context *fc)
 {
+	struct spufs_fs_context *ctx = fc->fs_private;
 	struct inode *inode;
-	int ret;
 
-	ret = -ENODEV;
 	if (!spu_management_ops)
-		goto out;
+		return -ENODEV;
 
-	ret = -ENOMEM;
-	inode = spufs_new_inode(sb, S_IFDIR | 0775);
+	inode = spufs_new_inode(sb, S_IFDIR | ctx->mode);
 	if (!inode)
-		goto out;
+		return -ENOMEM;
 
+	inode->i_uid = ctx->uid;
+	inode->i_gid = ctx->gid;
 	inode->i_op = &simple_dir_inode_operations;
 	inode->i_fop = &simple_dir_operations;
 	SPUFS_I(inode)->i_ctx = NULL;
 	inc_nlink(inode);
 
-	ret = -EINVAL;
-	if (!spufs_parse_options(sb, data, inode))
-		goto out_iput;
-
-	ret = -ENOMEM;
 	sb->s_root = d_make_root(inode);
 	if (!sb->s_root)
-		goto out;
-
+		return -ENOMEM;
 	return 0;
-out_iput:
-	iput(inode);
-out:
-	return ret;
 }
 
-static int
-spufs_fill_super(struct super_block *sb, void *data, int silent)
-{
-	struct spufs_sb_info *info;
-	static const struct super_operations s_ops = {
-		.alloc_inode = spufs_alloc_inode,
-		.destroy_inode = spufs_destroy_inode,
-		.statfs = simple_statfs,
-		.evict_inode = spufs_evict_inode,
-		.show_options = spufs_show_options,
-	};
-
-	info = kzalloc(sizeof(*info), GFP_KERNEL);
-	if (!info)
-		return -ENOMEM;
+static const struct super_operations spufs_ops = {
+	.alloc_inode	= spufs_alloc_inode,
+	.destroy_inode	= spufs_destroy_inode,
+	.statfs		= simple_statfs,
+	.evict_inode	= spufs_evict_inode,
+	.show_options	= spufs_show_options,
+};
 
+static int spufs_fill_super(struct super_block *sb, struct fs_context *fc)
+{
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
 	sb->s_blocksize = PAGE_SIZE;
 	sb->s_blocksize_bits = PAGE_SHIFT;
 	sb->s_magic = SPUFS_MAGIC;
-	sb->s_op = &s_ops;
-	sb->s_fs_info = info;
+	sb->s_op = &spufs_ops;
 
-	return spufs_create_root(sb, data);
+	return spufs_create_root(sb, fc);
+}
+
+static int spufs_get_tree(struct fs_context *fc)
+{
+	return vfs_get_super(fc, vfs_get_single_super, spufs_fill_super);
 }
 
-static struct dentry *
-spufs_mount(struct file_system_type *fstype, int flags,
-		const char *name, void *data)
+static void spufs_free_fc(struct fs_context *fc)
 {
-	return mount_single(fstype, flags, data, spufs_fill_super);
+	kfree(fc->s_fs_info);
+}
+
+static const struct fs_context_operations spufs_context_ops = {
+	.free		= spufs_free_fc,
+	.parse_param	= spufs_parse_param,
+	.get_tree	= spufs_get_tree,
+};
+
+static int spufs_init_fs_context(struct fs_context *fc)
+{
+	struct spufs_fs_context *ctx;
+	struct spufs_sb_info *sbi;
+
+	ctx = kzalloc(sizeof(struct spufs_fs_context), GFP_KERNEL);
+	if (!ctx)
+		goto nomem;
+
+	sbi = kzalloc(sizeof(struct spufs_sb_info), GFP_KERNEL);
+	if (!sbi)
+		goto nomem_ctx;
+
+	ctx->uid = current_uid();
+	ctx->gid = current_gid();
+	ctx->mode = 0755;
+
+	fc->s_fs_info = sbi;
+	fc->ops = &spufs_context_ops;
+	return 0;
+
+nomem_ctx:
+	kfree(ctx);
+nomem:
+	return -ENOMEM;
 }
 
 static struct file_system_type spufs_type = {
 	.owner = THIS_MODULE,
 	.name = "spufs",
-	.mount = spufs_mount,
+	.init_fs_context = spufs_init_fs_context,
+	.parameters	= &spufs_fs_parameters,
 	.kill_sb = kill_litter_super,
 };
 MODULE_ALIAS_FS("spufs");