kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted

Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit
`objtool` errors such as:

    vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a:
    can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd

The reason is that in such builds, the Clang invocation that compiles
the combined Rust plus helpers bitcode emits LLVM bitcode (again) --
the final code generation happens in the linker's LTO step, which the
`-mllvm` trap options passed to Clang do not reach.

This, in turn, means that unreachable traps are missing, and the
impossible paths do not merely fallthrough to the next symbol, but past
the end of their own section, since LTO builds place each function in
its own section.

Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always
emits machine code directly, with the traps in place.

Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 684 insertions, 0 deletions

diff --git a/fs/affs/super.c b/fs/affs/super.c
new file mode 100644
index 000000000..ed8225b3c
--- /dev/null
+++ b/fs/affs/super.c
@@ -0,0 +1,684 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/fs/affs/inode.c
+ *
+ *  (c) 1996  Hans-Joachim Widmaier - Rewritten
+ *
+ *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
+ *
+ *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
+ *
+ *  (C) 1991  Linus Torvalds - minix filesystem
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/statfs.h>
+#include <linux/fs_parser.h>
+#include <linux/fs_context.h>
+#include <linux/magic.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/slab.h>
+#include <linux/writeback.h>
+#include <linux/blkdev.h>
+#include <linux/seq_file.h>
+#include <linux/iversion.h>
+#include "affs.h"
+
+static int affs_statfs(struct dentry *dentry, struct kstatfs *buf);
+static int affs_show_options(struct seq_file *m, struct dentry *root);
+
+static void
+affs_commit_super(struct super_block *sb, int wait)
+{
+	struct affs_sb_info *sbi = AFFS_SB(sb);
+	struct buffer_head *bh = sbi->s_root_bh;
+	struct affs_root_tail *tail = AFFS_ROOT_TAIL(sb, bh);
+
+	lock_buffer(bh);
+	affs_secs_to_datestamp(ktime_get_real_seconds(), &tail->disk_change);
+	affs_fix_checksum(sb, bh);
+	unlock_buffer(bh);
+
+	mark_buffer_dirty(bh);
+	if (wait)
+		sync_dirty_buffer(bh);
+}
+
+static void
+affs_put_super(struct super_block *sb)
+{
+	struct affs_sb_info *sbi = AFFS_SB(sb);
+	pr_debug("%s()\n", __func__);
+
+	cancel_delayed_work_sync(&sbi->sb_work);
+}
+
+static int
+affs_sync_fs(struct super_block *sb, int wait)
+{
+	affs_commit_super(sb, wait);
+	return 0;
+}
+
+static void flush_superblock(struct work_struct *work)
+{
+	struct affs_sb_info *sbi;
+	struct super_block *sb;
+
+	sbi = container_of(work, struct affs_sb_info, sb_work.work);
+	sb = sbi->sb;
+
+	spin_lock(&sbi->work_lock);
+	sbi->work_queued = 0;
+	spin_unlock(&sbi->work_lock);
+
+	affs_commit_super(sb, 1);
+}
+
+void affs_mark_sb_dirty(struct super_block *sb)
+{
+	struct affs_sb_info *sbi = AFFS_SB(sb);
+	unsigned long delay;
+
+	if (sb_rdonly(sb))
+	       return;
+
+	spin_lock(&sbi->work_lock);
+	if (!sbi->work_queued) {
+	       delay = msecs_to_jiffies(dirty_writeback_interval * 10);
+	       queue_delayed_work(system_dfl_long_wq, &sbi->sb_work, delay);
+	       sbi->work_queued = 1;
+	}
+	spin_unlock(&sbi->work_lock);
+}
+
+static struct kmem_cache * affs_inode_cachep;
+
+static struct inode *affs_alloc_inode(struct super_block *sb)
+{
+	struct affs_inode_info *i;
+
+	i = alloc_inode_sb(sb, affs_inode_cachep, GFP_KERNEL);
+	if (!i)
+		return NULL;
+
+	inode_set_iversion(&i->vfs_inode, 1);
+	i->i_lc = NULL;
+	i->i_ext_bh = NULL;
+	i->i_pa_cnt = 0;
+
+	return &i->vfs_inode;
+}
+
+static void affs_free_inode(struct inode *inode)
+{
+	kmem_cache_free(affs_inode_cachep, AFFS_I(inode));
+}
+
+static void init_once(void *foo)
+{
+	struct affs_inode_info *ei = (struct affs_inode_info *) foo;
+
+	mutex_init(&ei->i_link_lock);
+	mutex_init(&ei->i_ext_lock);
+	inode_init_once(&ei->vfs_inode);
+}
+
+static int __init init_inodecache(void)
+{
+	affs_inode_cachep = kmem_cache_create("affs_inode_cache",
+					     sizeof(struct affs_inode_info),
+					     0, (SLAB_RECLAIM_ACCOUNT | SLAB_ACCOUNT),
+					     init_once);
+	if (affs_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+static void destroy_inodecache(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(affs_inode_cachep);
+}
+
+static const struct super_operations affs_sops = {
+	.alloc_inode	= affs_alloc_inode,
+	.free_inode	= affs_free_inode,
+	.write_inode	= affs_write_inode,
+	.evict_inode	= affs_evict_inode,
+	.put_super	= affs_put_super,
+	.sync_fs	= affs_sync_fs,
+	.statfs		= affs_statfs,
+	.show_options	= affs_show_options,
+};
+
+enum {
+	Opt_bs, Opt_mode, Opt_mufs, Opt_notruncate, Opt_prefix, Opt_protect,
+	Opt_reserved, Opt_root, Opt_setgid, Opt_setuid,
+	Opt_verbose, Opt_volume, Opt_ignore,
+};
+
+struct affs_context {
+	kuid_t		uid;		/* uid to override */
+	kgid_t		gid;		/* gid to override */
+	unsigned int	mode;		/* mode to override */
+	unsigned int	reserved;	/* Number of reserved blocks */
+	int		root_block;	/* FFS root block number */
+	int		blocksize;	/* Initial device blksize */
+	char		*prefix;	/* Prefix for volumes and assigns */
+	char		volume[32];	/* Vol. prefix for absolute symlinks */
+	unsigned long	mount_flags;	/* Options */
+};
+
+static const struct fs_parameter_spec affs_param_spec[] = {
+	fsparam_u32	("bs",		Opt_bs),
+	fsparam_u32oct	("mode",	Opt_mode),
+	fsparam_flag	("mufs",	Opt_mufs),
+	fsparam_flag	("nofilenametruncate",	Opt_notruncate),
+	fsparam_string	("prefix",	Opt_prefix),
+	fsparam_flag	("protect",	Opt_protect),
+	fsparam_u32	("reserved",	Opt_reserved),
+	fsparam_u32	("root",	Opt_root),
+	fsparam_gid	("setgid",	Opt_setgid),
+	fsparam_uid	("setuid",	Opt_setuid),
+	fsparam_flag	("verbose",	Opt_verbose),
+	fsparam_string	("volume",	Opt_volume),
+	fsparam_flag	("grpquota",	Opt_ignore),
+	fsparam_flag	("noquota",	Opt_ignore),
+	fsparam_flag	("quota",	Opt_ignore),
+	fsparam_flag	("usrquota",	Opt_ignore),
+	{},
+};
+
+static int affs_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct affs_context *ctx = fc->fs_private;
+	struct fs_parse_result result;
+	int n;
+	int opt;
+
+	opt = fs_parse(fc, affs_param_spec, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_bs:
+		n = result.uint_32;
+		if (n != 512 && n != 1024 && n != 2048
+		    && n != 4096) {
+			pr_warn("Invalid blocksize (512, 1024, 2048, 4096 allowed)\n");
+			return -EINVAL;
+		}
+		ctx->blocksize = n;
+		break;
+	case Opt_mode:
+		ctx->mode = result.uint_32 & 0777;
+		affs_set_opt(ctx->mount_flags, SF_SETMODE);
+		break;
+	case Opt_mufs:
+		affs_set_opt(ctx->mount_flags, SF_MUFS);
+		break;
+	case Opt_notruncate:
+		affs_set_opt(ctx->mount_flags, SF_NO_TRUNCATE);
+		break;
+	case Opt_prefix:
+		kfree(ctx->prefix);
+		ctx->prefix = param->string;
+		param->string = NULL;
+		affs_set_opt(ctx->mount_flags, SF_PREFIX);
+		break;
+	case Opt_protect:
+		affs_set_opt(ctx->mount_flags, SF_IMMUTABLE);
+		break;
+	case Opt_reserved:
+		ctx->reserved = result.uint_32;
+		break;
+	case Opt_root:
+		ctx->root_block = result.uint_32;
+		break;
+	case Opt_setgid:
+		ctx->gid = result.gid;
+		affs_set_opt(ctx->mount_flags, SF_SETGID);
+		break;
+	case Opt_setuid:
+		ctx->uid = result.uid;
+		affs_set_opt(ctx->mount_flags, SF_SETUID);
+		break;
+	case Opt_verbose:
+		affs_set_opt(ctx->mount_flags, SF_VERBOSE);
+		break;
+	case Opt_volume:
+		strscpy(ctx->volume, param->string, 32);
+		break;
+	case Opt_ignore:
+		/* Silently ignore the quota options */
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int affs_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct super_block *sb = root->d_sb;
+	struct affs_sb_info *sbi = AFFS_SB(sb);
+
+	if (sb->s_blocksize)
+		seq_printf(m, ",bs=%lu", sb->s_blocksize);
+	if (affs_test_opt(sbi->s_flags, SF_SETMODE))
+		seq_printf(m, ",mode=%o", sbi->s_mode);
+	if (affs_test_opt(sbi->s_flags, SF_MUFS))
+		seq_puts(m, ",mufs");
+	if (affs_test_opt(sbi->s_flags, SF_NO_TRUNCATE))
+		seq_puts(m, ",nofilenametruncate");
+	if (affs_test_opt(sbi->s_flags, SF_PREFIX))
+		seq_printf(m, ",prefix=%s", sbi->s_prefix);
+	if (affs_test_opt(sbi->s_flags, SF_IMMUTABLE))
+		seq_puts(m, ",protect");
+	if (sbi->s_reserved != 2)
+		seq_printf(m, ",reserved=%u", sbi->s_reserved);
+	if (sbi->s_root_block != (sbi->s_reserved + sbi->s_partition_size - 1) / 2)
+		seq_printf(m, ",root=%u", sbi->s_root_block);
+	if (affs_test_opt(sbi->s_flags, SF_SETGID))
+		seq_printf(m, ",setgid=%u",
+			   from_kgid_munged(&init_user_ns, sbi->s_gid));
+	if (affs_test_opt(sbi->s_flags, SF_SETUID))
+		seq_printf(m, ",setuid=%u",
+			   from_kuid_munged(&init_user_ns, sbi->s_uid));
+	if (affs_test_opt(sbi->s_flags, SF_VERBOSE))
+		seq_puts(m, ",verbose");
+	if (sbi->s_volume[0])
+		seq_printf(m, ",volume=%s", sbi->s_volume);
+	return 0;
+}
+
+/* This function definitely needs to be split up. Some fine day I'll
+ * hopefully have the guts to do so. Until then: sorry for the mess.
+ */
+
+static int affs_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+	struct affs_sb_info	*sbi;
+	struct affs_context	*ctx = fc->fs_private;
+	struct buffer_head	*root_bh = NULL;
+	struct buffer_head	*boot_bh;
+	struct inode		*root_inode = NULL;
+	int			 silent = fc->sb_flags & SB_SILENT;
+	int			 size, blocksize;
+	u32			 chksum;
+	int			 num_bm;
+	int			 i, j;
+	int			 tmp_flags;	/* fix remount prototype... */
+	u8			 sig[4];
+	int			 ret;
+
+	sb->s_magic             = AFFS_SUPER_MAGIC;
+	sb->s_op                = &affs_sops;
+	sb->s_flags |= SB_NODIRATIME;
+
+	sb->s_time_gran = NSEC_PER_SEC;
+	sb->s_time_min = sys_tz.tz_minuteswest * 60 + AFFS_EPOCH_DELTA;
+	sb->s_time_max = 86400LL * U32_MAX + 86400 + sb->s_time_min;
+
+	sbi = kzalloc_obj(struct affs_sb_info);
+	if (!sbi)
+		return -ENOMEM;
+
+	sb->s_fs_info = sbi;
+	sbi->sb = sb;
+	mutex_init(&sbi->s_bmlock);
+	spin_lock_init(&sbi->symlink_lock);
+	spin_lock_init(&sbi->work_lock);
+	INIT_DELAYED_WORK(&sbi->sb_work, flush_superblock);
+
+	sbi->s_flags	= ctx->mount_flags;
+	sbi->s_mode	= ctx->mode;
+	sbi->s_uid	= ctx->uid;
+	sbi->s_gid	= ctx->gid;
+	sbi->s_reserved	= ctx->reserved;
+	sbi->s_prefix	= ctx->prefix;
+	ctx->prefix	= NULL;
+	memcpy(sbi->s_volume, ctx->volume, 32);
+
+	/* N.B. after this point s_prefix must be released */
+
+	/* Get the size of the device in 512-byte blocks.
+	 * If we later see that the partition uses bigger
+	 * blocks, we will have to change it.
+	 */
+
+	size = bdev_nr_sectors(sb->s_bdev);
+	pr_debug("initial blocksize=%d, #blocks=%d\n", 512, size);
+
+	if (!sb_set_blocksize(sb, PAGE_SIZE))
+		return -EINVAL;
+	/* Try to find root block. Its location depends on the block size. */
+
+	i = bdev_logical_block_size(sb->s_bdev);
+	j = PAGE_SIZE;
+	blocksize = ctx->blocksize;
+	if (blocksize > 0) {
+		i = j = blocksize;
+		size = size / (blocksize / 512);
+	}
+
+	for (blocksize = i; blocksize <= j; blocksize <<= 1, size >>= 1) {
+		sbi->s_root_block = ctx->root_block;
+		if (ctx->root_block < 0)
+			sbi->s_root_block = (ctx->reserved + size - 1) / 2;
+		pr_debug("setting blocksize to %d\n", blocksize);
+		if (!sb_set_blocksize(sb, blocksize))
+			return -EINVAL;
+		sbi->s_partition_size = size;
+
+		/* The root block location that was calculated above is not
+		 * correct if the partition size is an odd number of 512-
+		 * byte blocks, which will be rounded down to a number of
+		 * 1024-byte blocks, and if there were an even number of
+		 * reserved blocks. Ideally, all partition checkers should
+		 * report the real number of blocks of the real blocksize,
+		 * but since this just cannot be done, we have to try to
+		 * find the root block anyways. In the above case, it is one
+		 * block behind the calculated one. So we check this one, too.
+		 */
+		for (num_bm = 0; num_bm < 2; num_bm++) {
+			pr_debug("Dev %s, trying root=%u, bs=%d, "
+				"size=%d, reserved=%d\n",
+				sb->s_id,
+				sbi->s_root_block + num_bm,
+				ctx->blocksize, size, ctx->reserved);
+			root_bh = affs_bread(sb, sbi->s_root_block + num_bm);
+			if (!root_bh)
+				continue;
+			if (!affs_checksum_block(sb, root_bh) &&
+			    be32_to_cpu(AFFS_ROOT_HEAD(root_bh)->ptype) == T_SHORT &&
+			    be32_to_cpu(AFFS_ROOT_TAIL(sb, root_bh)->stype) == ST_ROOT) {
+				sbi->s_hashsize    = blocksize / 4 - 56;
+				sbi->s_root_block += num_bm;
+				goto got_root;
+			}
+			affs_brelse(root_bh);
+			root_bh = NULL;
+		}
+	}
+	if (!silent)
+		pr_err("No valid root block on device %s\n", sb->s_id);
+	return -EINVAL;
+
+	/* N.B. after this point bh must be released */
+got_root:
+	/* Keep super block in cache */
+	sbi->s_root_bh = root_bh;
+	ctx->root_block = sbi->s_root_block;
+
+	/* Find out which kind of FS we have */
+	boot_bh = sb_bread(sb, 0);
+	if (!boot_bh) {
+		pr_err("Cannot read boot block\n");
+		return -EINVAL;
+	}
+	memcpy(sig, boot_bh->b_data, 4);
+	brelse(boot_bh);
+	chksum = be32_to_cpu(*(__be32 *)sig);
+
+	/* Dircache filesystems are compatible with non-dircache ones
+	 * when reading. As long as they aren't supported, writing is
+	 * not recommended.
+	 */
+	if ((chksum == FS_DCFFS || chksum == MUFS_DCFFS || chksum == FS_DCOFS
+	     || chksum == MUFS_DCOFS) && !sb_rdonly(sb)) {
+		pr_notice("Dircache FS - mounting %s read only\n", sb->s_id);
+		sb->s_flags |= SB_RDONLY;
+	}
+	switch (chksum) {
+	case MUFS_FS:
+	case MUFS_INTLFFS:
+	case MUFS_DCFFS:
+		affs_set_opt(sbi->s_flags, SF_MUFS);
+		fallthrough;
+	case FS_INTLFFS:
+	case FS_DCFFS:
+		affs_set_opt(sbi->s_flags, SF_INTL);
+		break;
+	case MUFS_FFS:
+		affs_set_opt(sbi->s_flags, SF_MUFS);
+		break;
+	case FS_FFS:
+		break;
+	case MUFS_OFS:
+		affs_set_opt(sbi->s_flags, SF_MUFS);
+		fallthrough;
+	case FS_OFS:
+		affs_set_opt(sbi->s_flags, SF_OFS);
+		sb->s_flags |= SB_NOEXEC;
+		break;
+	case MUFS_DCOFS:
+	case MUFS_INTLOFS:
+		affs_set_opt(sbi->s_flags, SF_MUFS);
+		fallthrough;
+	case FS_DCOFS:
+	case FS_INTLOFS:
+		affs_set_opt(sbi->s_flags, SF_INTL);
+		affs_set_opt(sbi->s_flags, SF_OFS);
+		sb->s_flags |= SB_NOEXEC;
+		break;
+	default:
+		pr_err("Unknown filesystem on device %s: %08X\n",
+		       sb->s_id, chksum);
+		return -EINVAL;
+	}
+
+	if (affs_test_opt(ctx->mount_flags, SF_VERBOSE)) {
+		u8 len = AFFS_ROOT_TAIL(sb, root_bh)->disk_name[0];
+		pr_notice("Mounting volume \"%.*s\": Type=%.3s\\%c, Blocksize=%d\n",
+			len > 31 ? 31 : len,
+			AFFS_ROOT_TAIL(sb, root_bh)->disk_name + 1,
+			sig, sig[3] + '0', blocksize);
+	}
+
+	sb->s_flags |= SB_NODEV | SB_NOSUID;
+
+	sbi->s_data_blksize = sb->s_blocksize;
+	if (affs_test_opt(sbi->s_flags, SF_OFS))
+		sbi->s_data_blksize -= 24;
+
+	tmp_flags = sb->s_flags;
+	ret = affs_init_bitmap(sb, &tmp_flags);
+	if (ret)
+		return ret;
+	sb->s_flags = tmp_flags;
+
+	/* set up enough so that it can read an inode */
+
+	root_inode = affs_iget(sb, ctx->root_block);
+	if (IS_ERR(root_inode))
+		return PTR_ERR(root_inode);
+
+	if (affs_test_opt(AFFS_SB(sb)->s_flags, SF_INTL))
+		set_default_d_op(sb, &affs_intl_dentry_operations);
+	else
+		set_default_d_op(sb, &affs_dentry_operations);
+
+	sb->s_root = d_make_root(root_inode);
+	if (!sb->s_root) {
+		pr_err("AFFS: Get root inode failed\n");
+		return -ENOMEM;
+	}
+
+	sb->s_export_op = &affs_export_ops;
+	pr_debug("s_flags=%lX\n", sb->s_flags);
+	return 0;
+}
+
+static int affs_reconfigure(struct fs_context *fc)
+{
+	struct super_block	*sb = fc->root->d_sb;
+	struct affs_context	*ctx = fc->fs_private;
+	struct affs_sb_info	*sbi = AFFS_SB(sb);
+	int			 res = 0;
+
+	sync_filesystem(sb);
+	fc->sb_flags |= SB_NODIRATIME;
+
+	flush_delayed_work(&sbi->sb_work);
+
+	/*
+	 * NB: Historically, only mount_flags, mode, uid, gic, prefix,
+	 * and volume are accepted during remount.
+	 */
+	sbi->s_flags = ctx->mount_flags;
+	sbi->s_mode  = ctx->mode;
+	sbi->s_uid   = ctx->uid;
+	sbi->s_gid   = ctx->gid;
+	/* protect against readers */
+	spin_lock(&sbi->symlink_lock);
+	if (ctx->prefix) {
+		kfree(sbi->s_prefix);
+		sbi->s_prefix = ctx->prefix;
+		ctx->prefix = NULL;
+	}
+	memcpy(sbi->s_volume, ctx->volume, 32);
+	spin_unlock(&sbi->symlink_lock);
+
+	if ((bool)(fc->sb_flags & SB_RDONLY) == sb_rdonly(sb))
+		return 0;
+
+	if (fc->sb_flags & SB_RDONLY)
+		affs_free_bitmap(sb);
+	else
+		res = affs_init_bitmap(sb, &fc->sb_flags);
+
+	return res;
+}
+
+static int
+affs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	int		 free;
+	u64		 id = huge_encode_dev(sb->s_bdev->bd_dev);
+
+	pr_debug("%s() partsize=%d, reserved=%d\n",
+		 __func__, AFFS_SB(sb)->s_partition_size,
+		 AFFS_SB(sb)->s_reserved);
+
+	free          = affs_count_free_blocks(sb);
+	buf->f_type    = AFFS_SUPER_MAGIC;
+	buf->f_bsize   = sb->s_blocksize;
+	buf->f_blocks  = AFFS_SB(sb)->s_partition_size - AFFS_SB(sb)->s_reserved;
+	buf->f_bfree   = free;
+	buf->f_bavail  = free;
+	buf->f_fsid    = u64_to_fsid(id);
+	buf->f_namelen = AFFSNAMEMAX;
+	return 0;
+}
+
+static int affs_get_tree(struct fs_context *fc)
+{
+	return get_tree_bdev(fc, affs_fill_super);
+}
+
+static void affs_kill_sb(struct super_block *sb)
+{
+	struct affs_sb_info *sbi = AFFS_SB(sb);
+	kill_block_super(sb);
+	if (sbi) {
+		affs_free_bitmap(sb);
+		affs_brelse(sbi->s_root_bh);
+		kfree(sbi->s_prefix);
+		mutex_destroy(&sbi->s_bmlock);
+		kfree_rcu(sbi, rcu);
+	}
+}
+
+static void affs_free_fc(struct fs_context *fc)
+{
+	struct affs_context *ctx = fc->fs_private;
+
+	kfree(ctx->prefix);
+	kfree(ctx);
+}
+
+static const struct fs_context_operations affs_context_ops = {
+	.parse_param	= affs_parse_param,
+	.get_tree	= affs_get_tree,
+	.reconfigure	= affs_reconfigure,
+	.free		= affs_free_fc,
+};
+
+static int affs_init_fs_context(struct fs_context *fc)
+{
+	struct affs_context *ctx;
+
+	ctx = kzalloc_obj(struct affs_context);
+	if (!ctx)
+		return -ENOMEM;
+
+	if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
+		struct super_block *sb = fc->root->d_sb;
+		struct affs_sb_info *sbi = AFFS_SB(sb);
+
+		/*
+		 * NB: historically, no options other than volume were
+		 * preserved across a remount unless they were explicitly
+		 * passed in.
+		 */
+		memcpy(ctx->volume, sbi->s_volume, 32);
+	} else {
+		ctx->uid	= current_uid();
+		ctx->gid	= current_gid();
+		ctx->reserved	= 2;
+		ctx->root_block	= -1;
+		ctx->blocksize	= -1;
+		ctx->volume[0]	= ':';
+	}
+
+	fc->ops = &affs_context_ops;
+	fc->fs_private = ctx;
+
+	return 0;
+}
+
+static struct file_system_type affs_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "affs",
+	.kill_sb	= affs_kill_sb,
+	.fs_flags	= FS_REQUIRES_DEV,
+	.init_fs_context = affs_init_fs_context,
+	.parameters	= affs_param_spec,
+};
+MODULE_ALIAS_FS("affs");
+
+static int __init init_affs_fs(void)
+{
+	int err = init_inodecache();
+	if (err)
+		goto out1;
+	err = register_filesystem(&affs_fs_type);
+	if (err)
+		goto out;
+	return 0;
+out:
+	destroy_inodecache();
+out1:
+	return err;
+}
+
+static void __exit exit_affs_fs(void)
+{
+	unregister_filesystem(&affs_fs_type);
+	destroy_inodecache();
+}
+
+MODULE_DESCRIPTION("Amiga filesystem support for Linux");
+MODULE_LICENSE("GPL");
+
+module_init(init_affs_fs)
+module_exit(exit_affs_fs)