x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 803 insertions, 0 deletions

diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
new file mode 100644
index 000000000..ff7d6b333
--- /dev/null
+++ b/fs/hfsplus/super.c
@@ -0,0 +1,803 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/fs/hfsplus/super.c
+ *
+ * Copyright (C) 2001
+ * Brad Boyer (flar@allandria.com)
+ * (C) 2003 Ardis Technologies <roman@ardistech.com>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/pagemap.h>
+#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
+#include <linux/fs.h>
+#include <linux/fs_context.h>
+#include <linux/slab.h>
+#include <linux/vfs.h>
+#include <linux/nls.h>
+
+static struct inode *hfsplus_alloc_inode(struct super_block *sb);
+static void hfsplus_free_inode(struct inode *inode);
+
+#include "hfsplus_fs.h"
+#include "xattr.h"
+
+static int hfsplus_system_read_inode(struct inode *inode)
+{
+	struct hfsplus_vh *vhdr = HFSPLUS_SB(inode->i_sb)->s_vhdr;
+
+	switch (inode->i_ino) {
+	case HFSPLUS_EXT_CNID:
+		hfsplus_inode_read_fork(inode, &vhdr->ext_file);
+		inode->i_mapping->a_ops = &hfsplus_btree_aops;
+		break;
+	case HFSPLUS_CAT_CNID:
+		hfsplus_inode_read_fork(inode, &vhdr->cat_file);
+		inode->i_mapping->a_ops = &hfsplus_btree_aops;
+		break;
+	case HFSPLUS_ALLOC_CNID:
+		hfsplus_inode_read_fork(inode, &vhdr->alloc_file);
+		inode->i_mapping->a_ops = &hfsplus_aops;
+		break;
+	case HFSPLUS_START_CNID:
+		hfsplus_inode_read_fork(inode, &vhdr->start_file);
+		break;
+	case HFSPLUS_ATTR_CNID:
+		hfsplus_inode_read_fork(inode, &vhdr->attr_file);
+		inode->i_mapping->a_ops = &hfsplus_btree_aops;
+		break;
+	default:
+		return -EIO;
+	}
+
+	/*
+	 * Assign a dummy file type, for may_open() requires that
+	 * an inode has a valid file type.
+	 */
+	inode->i_mode = S_IFREG;
+
+	return 0;
+}
+
+struct inode *hfsplus_iget(struct super_block *sb, unsigned long ino)
+{
+	struct hfs_find_data fd;
+	struct inode *inode;
+	int err;
+
+	inode = iget_locked(sb, ino);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode_state_read_once(inode) & I_NEW))
+		return inode;
+
+	atomic_set(&HFSPLUS_I(inode)->opencnt, 0);
+	HFSPLUS_I(inode)->first_blocks = 0;
+	HFSPLUS_I(inode)->clump_blocks = 0;
+	HFSPLUS_I(inode)->alloc_blocks = 0;
+	HFSPLUS_I(inode)->cached_start = U32_MAX;
+	HFSPLUS_I(inode)->cached_blocks = 0;
+	memset(HFSPLUS_I(inode)->first_extents, 0, sizeof(hfsplus_extent_rec));
+	memset(HFSPLUS_I(inode)->cached_extents, 0, sizeof(hfsplus_extent_rec));
+	HFSPLUS_I(inode)->extent_state = 0;
+	mutex_init(&HFSPLUS_I(inode)->extents_lock);
+	HFSPLUS_I(inode)->rsrc_inode = NULL;
+	HFSPLUS_I(inode)->create_date = 0;
+	HFSPLUS_I(inode)->linkid = 0;
+	HFSPLUS_I(inode)->flags = 0;
+	HFSPLUS_I(inode)->fs_blocks = 0;
+	HFSPLUS_I(inode)->userflags = 0;
+	HFSPLUS_I(inode)->subfolders = 0;
+	HFSPLUS_I(inode)->phys_size = 0;
+
+	if (inode->i_ino >= HFSPLUS_FIRSTUSER_CNID ||
+	    inode->i_ino == HFSPLUS_ROOT_CNID) {
+		err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
+		if (!err) {
+			err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
+			if (!err)
+				err = hfsplus_cat_read_inode(inode, &fd);
+			hfs_find_exit(&fd);
+		}
+	} else {
+		err = hfsplus_system_read_inode(inode);
+	}
+
+	if (err) {
+		iget_failed(inode);
+		return ERR_PTR(err);
+	}
+
+	unlock_new_inode(inode);
+	return inode;
+}
+
+static int hfsplus_system_write_inode(struct inode *inode)
+{
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(inode->i_sb);
+	struct hfsplus_vh *vhdr = sbi->s_vhdr;
+	struct hfsplus_fork_raw *fork;
+	struct hfs_btree *tree = NULL;
+
+	switch (inode->i_ino) {
+	case HFSPLUS_EXT_CNID:
+		fork = &vhdr->ext_file;
+		tree = sbi->ext_tree;
+		break;
+	case HFSPLUS_CAT_CNID:
+		fork = &vhdr->cat_file;
+		tree = sbi->cat_tree;
+		break;
+	case HFSPLUS_ALLOC_CNID:
+		fork = &vhdr->alloc_file;
+		break;
+	case HFSPLUS_START_CNID:
+		fork = &vhdr->start_file;
+		break;
+	case HFSPLUS_ATTR_CNID:
+		fork = &vhdr->attr_file;
+		tree = sbi->attr_tree;
+		break;
+	default:
+		return -EIO;
+	}
+
+	if (fork->total_size != cpu_to_be64(inode->i_size)) {
+		set_bit(HFSPLUS_SB_WRITEBACKUP, &sbi->flags);
+		hfsplus_mark_mdb_dirty(inode->i_sb);
+	}
+	hfsplus_inode_write_fork(inode, fork);
+	if (tree) {
+		mutex_lock_nested(&tree->tree_lock,
+				  hfsplus_btree_lock_class(tree));
+		int err = hfs_btree_write(tree);
+		mutex_unlock(&tree->tree_lock);
+
+		if (err) {
+			pr_err("b-tree write err: %d, ino %llu\n",
+			       err, inode->i_ino);
+			return err;
+		}
+	}
+	return 0;
+}
+
+static int hfsplus_write_inode(struct inode *inode,
+		struct writeback_control *wbc)
+{
+	int err;
+
+	hfs_dbg("ino %llu\n", inode->i_ino);
+
+	err = hfsplus_ext_write_extent(inode);
+	if (err)
+		return err;
+
+	if (inode->i_ino >= HFSPLUS_FIRSTUSER_CNID ||
+	    inode->i_ino == HFSPLUS_ROOT_CNID)
+		return hfsplus_cat_write_inode(inode);
+	else
+		return hfsplus_system_write_inode(inode);
+}
+
+static void hfsplus_evict_inode(struct inode *inode)
+{
+	hfs_dbg("ino %llu\n", inode->i_ino);
+	truncate_inode_pages_final(&inode->i_data);
+	clear_inode(inode);
+	if (HFSPLUS_IS_RSRC(inode)) {
+		HFSPLUS_I(HFSPLUS_I(inode)->rsrc_inode)->rsrc_inode = NULL;
+		iput(HFSPLUS_I(inode)->rsrc_inode);
+	}
+}
+
+int hfsplus_commit_superblock(struct super_block *sb)
+{
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+	struct hfsplus_vh *vhdr = sbi->s_vhdr;
+	int write_backup = 0;
+	int error = 0, error2;
+
+	hfs_dbg("starting...\n");
+
+	mutex_lock(&sbi->vh_mutex);
+	mutex_lock(&sbi->alloc_mutex);
+	vhdr->free_blocks = cpu_to_be32(sbi->free_blocks);
+	vhdr->next_cnid = cpu_to_be32(sbi->next_cnid);
+	vhdr->folder_count = cpu_to_be32(sbi->folder_count);
+	vhdr->file_count = cpu_to_be32(sbi->file_count);
+
+	hfs_dbg("free_blocks %u, next_cnid %u, folder_count %u, file_count %u\n",
+		sbi->free_blocks, sbi->next_cnid,
+		sbi->folder_count, sbi->file_count);
+
+	if (test_and_clear_bit(HFSPLUS_SB_WRITEBACKUP, &sbi->flags)) {
+		memcpy(sbi->s_backup_vhdr, sbi->s_vhdr, sizeof(*sbi->s_vhdr));
+		write_backup = 1;
+	}
+
+	error2 = hfsplus_submit_bio(sb,
+				   sbi->part_start + HFSPLUS_VOLHEAD_SECTOR,
+				   sbi->s_vhdr_buf, NULL, REQ_OP_WRITE);
+	if (!error)
+		error = error2;
+	if (!write_backup)
+		goto out;
+
+	error2 = hfsplus_submit_bio(sb,
+				  sbi->part_start + sbi->sect_count - 2,
+				  sbi->s_backup_vhdr_buf, NULL, REQ_OP_WRITE);
+	if (!error)
+		error = error2;
+out:
+	mutex_unlock(&sbi->alloc_mutex);
+	mutex_unlock(&sbi->vh_mutex);
+
+	hfs_dbg("finished: err %d\n", error);
+
+	return error;
+}
+
+static int hfsplus_sync_fs(struct super_block *sb, int wait)
+{
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+	int error, error2;
+
+	if (!wait)
+		return 0;
+
+	hfs_dbg("starting...\n");
+
+	/*
+	 * Explicitly write out the special metadata inodes.
+	 *
+	 * While these special inodes are marked as hashed and written
+	 * out peridocically by the flusher threads we redirty them
+	 * during writeout of normal inodes, and thus the life lock
+	 * prevents us from getting the latest state to disk.
+	 */
+	error = filemap_write_and_wait(sbi->cat_tree->inode->i_mapping);
+	error2 = filemap_write_and_wait(sbi->ext_tree->inode->i_mapping);
+	if (!error)
+		error = error2;
+	if (sbi->attr_tree) {
+		error2 =
+		    filemap_write_and_wait(sbi->attr_tree->inode->i_mapping);
+		if (!error)
+			error = error2;
+	}
+	error2 = filemap_write_and_wait(sbi->alloc_file->i_mapping);
+	if (!error)
+		error = error2;
+
+	error2 = hfsplus_commit_superblock(sb);
+	if (!error)
+		error = error2;
+
+	if (!test_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags))
+		blkdev_issue_flush(sb->s_bdev);
+
+	hfs_dbg("finished: err %d\n", error);
+
+	return error;
+}
+
+static void delayed_sync_fs(struct work_struct *work)
+{
+	int err;
+	struct hfsplus_sb_info *sbi;
+
+	sbi = container_of(work, struct hfsplus_sb_info, sync_work.work);
+
+	spin_lock(&sbi->work_lock);
+	sbi->work_queued = 0;
+	spin_unlock(&sbi->work_lock);
+
+	err = hfsplus_sync_fs(sbi->alloc_file->i_sb, 1);
+	if (err)
+		pr_err("delayed sync fs err %d\n", err);
+}
+
+void hfsplus_mark_mdb_dirty(struct super_block *sb)
+{
+	struct hfsplus_sb_info *sbi = HFSPLUS_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->sync_work, delay);
+		sbi->work_queued = 1;
+	}
+	spin_unlock(&sbi->work_lock);
+}
+
+static void delayed_free(struct rcu_head *p)
+{
+	struct hfsplus_sb_info *sbi = container_of(p, struct hfsplus_sb_info, rcu);
+
+	unload_nls(sbi->nls);
+	kfree(sbi);
+}
+
+static void hfsplus_put_super(struct super_block *sb)
+{
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+
+	hfs_dbg("starting...\n");
+
+	cancel_delayed_work_sync(&sbi->sync_work);
+
+	if (!sb_rdonly(sb) && sbi->s_vhdr) {
+		struct hfsplus_vh *vhdr = sbi->s_vhdr;
+
+		vhdr->modify_date = hfsp_now2mt();
+		vhdr->attributes |= cpu_to_be32(HFSPLUS_VOL_UNMNT);
+		vhdr->attributes &= cpu_to_be32(~HFSPLUS_VOL_INCNSTNT);
+
+		hfsplus_sync_fs(sb, 1);
+	}
+
+	iput(sbi->alloc_file);
+	iput(sbi->hidden_dir);
+	hfs_btree_close(sbi->attr_tree);
+	hfs_btree_close(sbi->cat_tree);
+	hfs_btree_close(sbi->ext_tree);
+	kfree(sbi->s_vhdr_buf);
+	kfree(sbi->s_backup_vhdr_buf);
+	hfs_dbg("finished\n");
+}
+
+static int hfsplus_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
+
+	buf->f_type = HFSPLUS_SUPER_MAGIC;
+	buf->f_bsize = sb->s_blocksize;
+	buf->f_blocks = sbi->total_blocks << sbi->fs_shift;
+	buf->f_bfree = sbi->free_blocks << sbi->fs_shift;
+	buf->f_bavail = buf->f_bfree;
+	buf->f_files = 0xFFFFFFFF;
+	buf->f_ffree = 0xFFFFFFFF - sbi->next_cnid;
+	buf->f_fsid = u64_to_fsid(id);
+	buf->f_namelen = HFSPLUS_MAX_STRLEN;
+
+	return 0;
+}
+
+static int hfsplus_reconfigure(struct fs_context *fc)
+{
+	struct super_block *sb = fc->root->d_sb;
+
+	sync_filesystem(sb);
+	if ((bool)(fc->sb_flags & SB_RDONLY) == sb_rdonly(sb))
+		return 0;
+	if (!(fc->sb_flags & SB_RDONLY)) {
+		struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+		struct hfsplus_vh *vhdr = sbi->s_vhdr;
+
+		if (!(vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_UNMNT))) {
+			pr_warn("filesystem was not cleanly unmounted, running fsck.hfsplus is recommended.  leaving read-only.\n");
+			sb->s_flags |= SB_RDONLY;
+			fc->sb_flags |= SB_RDONLY;
+		} else if (test_bit(HFSPLUS_SB_FORCE, &sbi->flags)) {
+			/* nothing */
+		} else if (vhdr->attributes &
+				cpu_to_be32(HFSPLUS_VOL_SOFTLOCK)) {
+			pr_warn("filesystem is marked locked, leaving read-only.\n");
+			sb->s_flags |= SB_RDONLY;
+			fc->sb_flags |= SB_RDONLY;
+		} else if (vhdr->attributes &
+				cpu_to_be32(HFSPLUS_VOL_JOURNALED)) {
+			pr_warn("filesystem is marked journaled, leaving read-only.\n");
+			sb->s_flags |= SB_RDONLY;
+			fc->sb_flags |= SB_RDONLY;
+		}
+	}
+	return 0;
+}
+
+static const struct super_operations hfsplus_sops = {
+	.alloc_inode	= hfsplus_alloc_inode,
+	.free_inode	= hfsplus_free_inode,
+	.write_inode	= hfsplus_write_inode,
+	.evict_inode	= hfsplus_evict_inode,
+	.put_super	= hfsplus_put_super,
+	.sync_fs	= hfsplus_sync_fs,
+	.statfs		= hfsplus_statfs,
+	.show_options	= hfsplus_show_options,
+};
+
+void hfsplus_prepare_volume_header_for_commit(struct hfsplus_vh *vhdr)
+{
+	vhdr->last_mount_vers = cpu_to_be32(HFSP_MOUNT_VERSION);
+	vhdr->modify_date = hfsp_now2mt();
+	be32_add_cpu(&vhdr->write_count, 1);
+	vhdr->attributes &= cpu_to_be32(~HFSPLUS_VOL_UNMNT);
+	vhdr->attributes |= cpu_to_be32(HFSPLUS_VOL_INCNSTNT);
+}
+
+static inline int hfsplus_get_hidden_dir_entry(struct super_block *sb,
+					       const struct qstr *str,
+					       hfsplus_cat_entry *entry)
+{
+	struct hfs_find_data fd;
+	int err;
+
+	err = hfs_find_init(HFSPLUS_SB(sb)->cat_tree, &fd);
+	if (unlikely(err))
+		return err;
+
+	err = hfsplus_cat_build_key(sb, fd.search_key, HFSPLUS_ROOT_CNID, str);
+	if (unlikely(err))
+		goto free_fd;
+
+	err = hfsplus_brec_read_cat(&fd, entry);
+	if (err)
+		err = -ENOENT;
+
+free_fd:
+	hfs_find_exit(&fd);
+	return err;
+}
+
+static int hfsplus_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+	struct hfsplus_vh *vhdr;
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+	hfsplus_cat_entry entry;
+	struct inode *root, *inode;
+	struct qstr str;
+	struct nls_table *nls;
+	u64 last_fs_block, last_fs_page;
+	int silent = fc->sb_flags & SB_SILENT;
+	int err;
+
+	mutex_init(&sbi->alloc_mutex);
+	mutex_init(&sbi->vh_mutex);
+	spin_lock_init(&sbi->work_lock);
+	INIT_DELAYED_WORK(&sbi->sync_work, delayed_sync_fs);
+
+	err = -EINVAL;
+	if (!sbi->nls) {
+		/* try utf8 first, as this is the old default behaviour */
+		sbi->nls = load_nls("utf8");
+		if (!sbi->nls)
+			sbi->nls = load_nls_default();
+	}
+
+	/* temporarily use utf8 to correctly find the hidden dir below */
+	nls = sbi->nls;
+	sbi->nls = load_nls("utf8");
+	if (!sbi->nls) {
+		pr_err("unable to load nls for utf8\n");
+		goto out_unload_nls;
+	}
+
+	/* Grab the volume header */
+	if (hfsplus_read_wrapper(sb)) {
+		if (!silent)
+			pr_warn("unable to find HFS+ superblock\n");
+		goto out_unload_nls;
+	}
+	vhdr = sbi->s_vhdr;
+
+	/* Copy parts of the volume header into the superblock */
+	sb->s_magic = HFSPLUS_VOLHEAD_SIG;
+	if (be16_to_cpu(vhdr->version) < HFSPLUS_MIN_VERSION ||
+	    be16_to_cpu(vhdr->version) > HFSPLUS_CURRENT_VERSION) {
+		pr_err("wrong filesystem version\n");
+		goto out_free_vhdr;
+	}
+	sbi->total_blocks = be32_to_cpu(vhdr->total_blocks);
+	sbi->free_blocks = be32_to_cpu(vhdr->free_blocks);
+	sbi->next_cnid = be32_to_cpu(vhdr->next_cnid);
+	sbi->file_count = be32_to_cpu(vhdr->file_count);
+	sbi->folder_count = be32_to_cpu(vhdr->folder_count);
+	sbi->data_clump_blocks =
+		be32_to_cpu(vhdr->data_clump_sz) >> sbi->alloc_blksz_shift;
+	if (!sbi->data_clump_blocks)
+		sbi->data_clump_blocks = 1;
+	sbi->rsrc_clump_blocks =
+		be32_to_cpu(vhdr->rsrc_clump_sz) >> sbi->alloc_blksz_shift;
+	if (!sbi->rsrc_clump_blocks)
+		sbi->rsrc_clump_blocks = 1;
+
+	err = -EFBIG;
+	last_fs_block = sbi->total_blocks - 1;
+	last_fs_page = (last_fs_block << sbi->alloc_blksz_shift) >>
+			PAGE_SHIFT;
+
+	if ((last_fs_block > (sector_t)(~0ULL) >> (sbi->alloc_blksz_shift - 9)) ||
+	    (last_fs_page > (pgoff_t)(~0ULL))) {
+		pr_err("filesystem size too large\n");
+		goto out_free_vhdr;
+	}
+
+	/* Set up operations so we can load metadata */
+	sb->s_op = &hfsplus_sops;
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+
+	if (!(vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_UNMNT))) {
+		pr_warn("Filesystem was not cleanly unmounted, running fsck.hfsplus is recommended.  mounting read-only.\n");
+		sb->s_flags |= SB_RDONLY;
+	} else if (test_and_clear_bit(HFSPLUS_SB_FORCE, &sbi->flags)) {
+		/* nothing */
+	} else if (vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_SOFTLOCK)) {
+		pr_warn("Filesystem is marked locked, mounting read-only.\n");
+		sb->s_flags |= SB_RDONLY;
+	} else if ((vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_JOURNALED)) &&
+			!sb_rdonly(sb)) {
+		pr_warn("write access to a journaled filesystem is not supported, use the force option at your own risk, mounting read-only.\n");
+		sb->s_flags |= SB_RDONLY;
+	}
+
+	err = -EINVAL;
+
+	/* Load metadata objects (B*Trees) */
+	sbi->ext_tree = hfs_btree_open(sb, HFSPLUS_EXT_CNID);
+	if (!sbi->ext_tree) {
+		pr_err("failed to load extents file\n");
+		goto out_free_vhdr;
+	}
+	sbi->cat_tree = hfs_btree_open(sb, HFSPLUS_CAT_CNID);
+	if (!sbi->cat_tree) {
+		pr_err("failed to load catalog file\n");
+		goto out_close_ext_tree;
+	}
+	atomic_set(&sbi->attr_tree_state, HFSPLUS_EMPTY_ATTR_TREE);
+	if (vhdr->attr_file.total_blocks != 0) {
+		sbi->attr_tree = hfs_btree_open(sb, HFSPLUS_ATTR_CNID);
+		if (!sbi->attr_tree) {
+			pr_err("failed to load attributes file\n");
+			goto out_close_cat_tree;
+		}
+		atomic_set(&sbi->attr_tree_state, HFSPLUS_VALID_ATTR_TREE);
+	}
+	sb->s_xattr = hfsplus_xattr_handlers;
+
+	inode = hfsplus_iget(sb, HFSPLUS_ALLOC_CNID);
+	if (IS_ERR(inode)) {
+		pr_err("failed to load allocation file\n");
+		err = PTR_ERR(inode);
+		goto out_close_attr_tree;
+	}
+	sbi->alloc_file = inode;
+
+	/* Load the root directory */
+	root = hfsplus_iget(sb, HFSPLUS_ROOT_CNID);
+	if (IS_ERR(root)) {
+		pr_err("failed to load root directory\n");
+		err = PTR_ERR(root);
+		goto out_put_alloc_file;
+	}
+
+	set_default_d_op(sb, &hfsplus_dentry_operations);
+	sb->s_root = d_make_root(root);
+	if (!sb->s_root) {
+		err = -ENOMEM;
+		goto out_put_alloc_file;
+	}
+
+	str.len = sizeof(HFSP_HIDDENDIR_NAME) - 1;
+	str.name = HFSP_HIDDENDIR_NAME;
+	err = hfsplus_get_hidden_dir_entry(sb, &str, &entry);
+	if (err == -ENOENT) {
+		/*
+		 * Hidden directory is absent or it cannot be read.
+		 */
+	} else if (unlikely(err)) {
+		goto out_put_root;
+	} else {
+		if (entry.type != cpu_to_be16(HFSPLUS_FOLDER)) {
+			err = -EIO;
+			goto out_put_root;
+		}
+		inode = hfsplus_iget(sb, be32_to_cpu(entry.folder.id));
+		if (IS_ERR(inode)) {
+			err = PTR_ERR(inode);
+			goto out_put_root;
+		}
+		sbi->hidden_dir = inode;
+	}
+
+	if (!sb_rdonly(sb)) {
+		/*
+		 * H+LX == hfsplusutils, H+Lx == this driver, H+lx is unused
+		 * all three are registered with Apple for our use
+		 */
+		hfsplus_prepare_volume_header_for_commit(vhdr);
+		hfsplus_sync_fs(sb, 1);
+
+		if (!sbi->hidden_dir) {
+			mutex_lock(&sbi->vh_mutex);
+			sbi->hidden_dir = hfsplus_new_inode(sb, root, S_IFDIR);
+			if (!sbi->hidden_dir) {
+				mutex_unlock(&sbi->vh_mutex);
+				err = -ENOMEM;
+				goto out_put_root;
+			}
+			err = hfsplus_create_cat(sbi->hidden_dir->i_ino, root,
+						 &str, sbi->hidden_dir);
+			if (err) {
+				mutex_unlock(&sbi->vh_mutex);
+				goto out_put_hidden_dir;
+			}
+
+			err = hfsplus_init_security(sbi->hidden_dir,
+							root, &str);
+			if (err == -EOPNOTSUPP)
+				err = 0; /* Operation is not supported. */
+			else if (err) {
+				/*
+				 * Try to delete anyway without
+				 * error analysis.
+				 */
+				hfsplus_delete_cat(sbi->hidden_dir->i_ino,
+							root, &str);
+				mutex_unlock(&sbi->vh_mutex);
+				goto out_put_hidden_dir;
+			}
+
+			mutex_unlock(&sbi->vh_mutex);
+			hfsplus_mark_inode_dirty(HFSPLUS_CAT_TREE_I(sb),
+						 HFSPLUS_I_CAT_DIRTY);
+			hfsplus_mark_inode_dirty(sbi->hidden_dir,
+						 HFSPLUS_I_CAT_DIRTY);
+		}
+	}
+
+	unload_nls(sbi->nls);
+	sbi->nls = nls;
+	return 0;
+
+out_put_hidden_dir:
+	cancel_delayed_work_sync(&sbi->sync_work);
+	iput(sbi->hidden_dir);
+out_put_root:
+	dput(sb->s_root);
+	sb->s_root = NULL;
+out_put_alloc_file:
+	iput(sbi->alloc_file);
+out_close_attr_tree:
+	hfs_btree_close(sbi->attr_tree);
+out_close_cat_tree:
+	hfs_btree_close(sbi->cat_tree);
+out_close_ext_tree:
+	hfs_btree_close(sbi->ext_tree);
+out_free_vhdr:
+	kfree(sbi->s_vhdr_buf);
+	kfree(sbi->s_backup_vhdr_buf);
+out_unload_nls:
+	unload_nls(nls);
+	return err;
+}
+
+MODULE_AUTHOR("Brad Boyer");
+MODULE_DESCRIPTION("Extended Macintosh Filesystem");
+MODULE_LICENSE("GPL");
+
+static struct kmem_cache *hfsplus_inode_cachep;
+
+static struct inode *hfsplus_alloc_inode(struct super_block *sb)
+{
+	struct hfsplus_inode_info *i;
+
+	i = alloc_inode_sb(sb, hfsplus_inode_cachep, GFP_KERNEL);
+	return i ? &i->vfs_inode : NULL;
+}
+
+static void hfsplus_free_inode(struct inode *inode)
+{
+	kmem_cache_free(hfsplus_inode_cachep, HFSPLUS_I(inode));
+}
+
+#define HFSPLUS_INODE_SIZE	sizeof(struct hfsplus_inode_info)
+
+static int hfsplus_get_tree(struct fs_context *fc)
+{
+	return get_tree_bdev(fc, hfsplus_fill_super);
+}
+
+static void hfsplus_free_fc(struct fs_context *fc)
+{
+	kfree(fc->s_fs_info);
+}
+
+static const struct fs_context_operations hfsplus_context_ops = {
+	.parse_param	= hfsplus_parse_param,
+	.get_tree	= hfsplus_get_tree,
+	.reconfigure	= hfsplus_reconfigure,
+	.free		= hfsplus_free_fc,
+};
+
+static int hfsplus_init_fs_context(struct fs_context *fc)
+{
+	struct hfsplus_sb_info *sbi;
+
+	sbi = kzalloc_obj(struct hfsplus_sb_info);
+	if (!sbi)
+		return -ENOMEM;
+
+	if (fc->purpose != FS_CONTEXT_FOR_RECONFIGURE)
+		hfsplus_fill_defaults(sbi);
+
+	fc->s_fs_info = sbi;
+	fc->ops = &hfsplus_context_ops;
+
+	return 0;
+}
+
+static void hfsplus_kill_super(struct super_block *sb)
+{
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+
+	kill_block_super(sb);
+	call_rcu(&sbi->rcu, delayed_free);
+}
+
+static struct file_system_type hfsplus_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "hfsplus",
+	.kill_sb	= hfsplus_kill_super,
+	.fs_flags	= FS_REQUIRES_DEV,
+	.init_fs_context = hfsplus_init_fs_context,
+};
+MODULE_ALIAS_FS("hfsplus");
+
+static void hfsplus_init_once(void *p)
+{
+	struct hfsplus_inode_info *i = p;
+
+	inode_init_once(&i->vfs_inode);
+}
+
+static int __init init_hfsplus_fs(void)
+{
+	int err;
+
+	hfsplus_inode_cachep = kmem_cache_create("hfsplus_icache",
+		HFSPLUS_INODE_SIZE, 0, SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT,
+		hfsplus_init_once);
+	if (!hfsplus_inode_cachep)
+		return -ENOMEM;
+	err = hfsplus_create_attr_tree_cache();
+	if (err)
+		goto destroy_inode_cache;
+	err = register_filesystem(&hfsplus_fs_type);
+	if (err)
+		goto destroy_attr_tree_cache;
+	return 0;
+
+destroy_attr_tree_cache:
+	hfsplus_destroy_attr_tree_cache();
+
+destroy_inode_cache:
+	kmem_cache_destroy(hfsplus_inode_cachep);
+
+	return err;
+}
+
+static void __exit exit_hfsplus_fs(void)
+{
+	unregister_filesystem(&hfsplus_fs_type);
+
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	hfsplus_destroy_attr_tree_cache();
+	kmem_cache_destroy(hfsplus_inode_cachep);
+}
+
+module_init(init_hfsplus_fs)
+module_exit(exit_hfsplus_fs)