Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

6 files changed, 1195 insertions, 0 deletions

diff --git a/fs/bfs/Kconfig b/fs/bfs/Kconfig
new file mode 100644
index 000000000..8e7ef866b
--- /dev/null
+++ b/fs/bfs/Kconfig
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config BFS_FS
+	tristate "BFS file system support"
+	depends on BLOCK
+	select BUFFER_HEAD
+	help
+	  Boot File System (BFS) is a file system used under SCO UnixWare to
+	  allow the bootloader access to the kernel image and other important
+	  files during the boot process.  It is usually mounted under /stand
+	  and corresponds to the slice marked as "STAND" in the UnixWare
+	  partition.  You should say Y if you want to read or write the files
+	  on your /stand slice from within Linux.  You then also need to say Y
+	  to "UnixWare slices support", below.  More information about the BFS
+	  file system is contained in the file
+	  <file:Documentation/filesystems/bfs.rst>.
+
+	  If you don't know what this is about, say N.
+
+	  To compile this as a module, choose M here: the module will be called
+	  bfs.  Note that the file system of your root partition (the one
+	  containing the directory /) cannot be compiled as a module.
diff --git a/fs/bfs/Makefile b/fs/bfs/Makefile
new file mode 100644
index 000000000..2b6bc5eb4
--- /dev/null
+++ b/fs/bfs/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for BFS filesystem.
+#
+
+obj-$(CONFIG_BFS_FS) += bfs.o
+
+bfs-objs := inode.o file.o dir.o
diff --git a/fs/bfs/bfs.h b/fs/bfs/bfs.h
new file mode 100644
index 000000000..b08afe733
--- /dev/null
+++ b/fs/bfs/bfs.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *	fs/bfs/bfs.h
+ *	Copyright (C) 1999-2018 Tigran Aivazian <aivazian.tigran@gmail.com>
+ */
+#ifndef _FS_BFS_BFS_H
+#define _FS_BFS_BFS_H
+
+#include <linux/bfs_fs.h>
+
+/* In theory BFS supports up to 512 inodes, numbered from 2 (for /) up to 513 inclusive.
+   In actual fact, attempting to create the 512th inode (i.e. inode No. 513 or file No. 511)
+   will fail with ENOSPC in bfs_add_entry(): the root directory cannot contain so many entries, counting '..'.
+   So, mkfs.bfs(8) should really limit its -N option to 511 and not 512. For now, we just print a warning
+   if a filesystem is mounted with such "impossible to fill up" number of inodes */
+#define BFS_MAX_LASTI	513
+
+/*
+ * BFS file system in-core superblock info
+ */
+struct bfs_sb_info {
+	unsigned long si_blocks;
+	unsigned long si_freeb;
+	unsigned long si_freei;
+	unsigned long si_lf_eblk;
+	unsigned long si_lasti;
+	DECLARE_BITMAP(si_imap, BFS_MAX_LASTI+1);
+	struct mutex bfs_lock;
+};
+
+/*
+ * BFS file system in-core inode info
+ */
+struct bfs_inode_info {
+	unsigned long i_dsk_ino; /* inode number from the disk, can be 0 */
+	unsigned long i_sblock;
+	unsigned long i_eblock;
+	struct mapping_metadata_bhs i_metadata_bhs;
+	struct inode vfs_inode;
+};
+
+static inline struct bfs_sb_info *BFS_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+static inline struct bfs_inode_info *BFS_I(struct inode *inode)
+{
+	return container_of(inode, struct bfs_inode_info, vfs_inode);
+}
+
+
+#define printf(format, args...) \
+	printk(KERN_ERR "BFS-fs: %s(): " format, __func__, ## args)
+
+/* inode.c */
+extern struct inode *bfs_iget(struct super_block *sb, unsigned long ino);
+extern void bfs_dump_imap(const char *, struct super_block *);
+
+/* file.c */
+extern const struct inode_operations bfs_file_inops;
+extern const struct file_operations bfs_file_operations;
+extern const struct address_space_operations bfs_aops;
+
+/* dir.c */
+extern const struct inode_operations bfs_dir_inops;
+extern const struct file_operations bfs_dir_operations;
+
+#endif /* _FS_BFS_BFS_H */
diff --git a/fs/bfs/dir.c b/fs/bfs/dir.c
new file mode 100644
index 000000000..91a4871fa
--- /dev/null
+++ b/fs/bfs/dir.c
@@ -0,0 +1,356 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *	fs/bfs/dir.c
+ *	BFS directory operations.
+ *	Copyright (C) 1999-2018  Tigran Aivazian <aivazian.tigran@gmail.com>
+ *  Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005
+ */
+
+#include <linux/time.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/sched.h>
+#include "bfs.h"
+
+#undef DEBUG
+
+#ifdef DEBUG
+#define dprintf(x...)	printf(x)
+#else
+#define dprintf(x...)
+#endif
+
+static int bfs_add_entry(struct inode *dir, const struct qstr *child, int ino);
+static struct buffer_head *bfs_find_entry(struct inode *dir,
+				const struct qstr *child,
+				struct bfs_dirent **res_dir);
+
+static int bfs_readdir(struct file *f, struct dir_context *ctx)
+{
+	struct inode *dir = file_inode(f);
+	struct buffer_head *bh;
+	struct bfs_dirent *de;
+	unsigned int offset;
+	int block;
+
+	if (ctx->pos & (BFS_DIRENT_SIZE - 1)) {
+		printf("Bad f_pos=%08lx for %s:%08llx\n",
+					(unsigned long)ctx->pos,
+					dir->i_sb->s_id, dir->i_ino);
+		return -EINVAL;
+	}
+
+	while (ctx->pos < dir->i_size) {
+		offset = ctx->pos & (BFS_BSIZE - 1);
+		block = BFS_I(dir)->i_sblock + (ctx->pos >> BFS_BSIZE_BITS);
+		bh = sb_bread(dir->i_sb, block);
+		if (!bh) {
+			ctx->pos += BFS_BSIZE - offset;
+			continue;
+		}
+		do {
+			de = (struct bfs_dirent *)(bh->b_data + offset);
+			if (de->ino) {
+				int size = strnlen(de->name, BFS_NAMELEN);
+				if (!dir_emit(ctx, de->name, size,
+						le16_to_cpu(de->ino),
+						DT_UNKNOWN)) {
+					brelse(bh);
+					return 0;
+				}
+			}
+			offset += BFS_DIRENT_SIZE;
+			ctx->pos += BFS_DIRENT_SIZE;
+		} while ((offset < BFS_BSIZE) && (ctx->pos < dir->i_size));
+		brelse(bh);
+	}
+	return 0;
+}
+
+const struct file_operations bfs_dir_operations = {
+	.read		= generic_read_dir,
+	.iterate_shared	= bfs_readdir,
+	.fsync		= simple_fsync,
+	.llseek		= generic_file_llseek,
+};
+
+static int bfs_create(struct mnt_idmap *idmap, struct inode *dir,
+		      struct dentry *dentry, umode_t mode)
+{
+	int err;
+	struct inode *inode;
+	struct super_block *s = dir->i_sb;
+	struct bfs_sb_info *info = BFS_SB(s);
+	unsigned long ino;
+
+	inode = new_inode(s);
+	if (!inode)
+		return -ENOMEM;
+	mutex_lock(&info->bfs_lock);
+	ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1);
+	if (ino > info->si_lasti) {
+		mutex_unlock(&info->bfs_lock);
+		iput(inode);
+		return -ENOSPC;
+	}
+	set_bit(ino, info->si_imap);
+	info->si_freei--;
+	inode_init_owner(&nop_mnt_idmap, inode, dir, mode);
+	simple_inode_init_ts(inode);
+	inode->i_blocks = 0;
+	inode->i_op = &bfs_file_inops;
+	inode->i_fop = &bfs_file_operations;
+	inode->i_mapping->a_ops = &bfs_aops;
+	inode->i_ino = ino;
+	BFS_I(inode)->i_dsk_ino = ino;
+	BFS_I(inode)->i_sblock = 0;
+	BFS_I(inode)->i_eblock = 0;
+	insert_inode_hash(inode);
+        mark_inode_dirty(inode);
+	bfs_dump_imap("create", s);
+
+	err = bfs_add_entry(dir, &dentry->d_name, inode->i_ino);
+	if (err) {
+		inode_dec_link_count(inode);
+		mutex_unlock(&info->bfs_lock);
+		iput(inode);
+		return err;
+	}
+	mutex_unlock(&info->bfs_lock);
+	d_instantiate(dentry, inode);
+	return 0;
+}
+
+static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
+						unsigned int flags)
+{
+	struct inode *inode = NULL;
+	struct buffer_head *bh;
+	struct bfs_dirent *de;
+	struct bfs_sb_info *info = BFS_SB(dir->i_sb);
+
+	if (dentry->d_name.len > BFS_NAMELEN)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	mutex_lock(&info->bfs_lock);
+	bh = bfs_find_entry(dir, &dentry->d_name, &de);
+	if (bh) {
+		unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
+		brelse(bh);
+		inode = bfs_iget(dir->i_sb, ino);
+	}
+	mutex_unlock(&info->bfs_lock);
+	return d_splice_alias(inode, dentry);
+}
+
+static int bfs_link(struct dentry *old, struct inode *dir,
+						struct dentry *new)
+{
+	struct inode *inode = d_inode(old);
+	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
+	int err;
+
+	mutex_lock(&info->bfs_lock);
+	err = bfs_add_entry(dir, &new->d_name, inode->i_ino);
+	if (err) {
+		mutex_unlock(&info->bfs_lock);
+		return err;
+	}
+	inc_nlink(inode);
+	inode_set_ctime_current(inode);
+	mark_inode_dirty(inode);
+	ihold(inode);
+	d_instantiate(new, inode);
+	mutex_unlock(&info->bfs_lock);
+	return 0;
+}
+
+static int bfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+	int error = -ENOENT;
+	struct inode *inode = d_inode(dentry);
+	struct buffer_head *bh;
+	struct bfs_dirent *de;
+	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
+
+	mutex_lock(&info->bfs_lock);
+	bh = bfs_find_entry(dir, &dentry->d_name, &de);
+	if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
+		goto out_brelse;
+
+	if (!inode->i_nlink) {
+		printf("unlinking non-existent file %s:%llu (nlink=%d)\n",
+					inode->i_sb->s_id, inode->i_ino,
+					inode->i_nlink);
+		set_nlink(inode, 1);
+	}
+	de->ino = 0;
+	mmb_mark_buffer_dirty(bh, &BFS_I(dir)->i_metadata_bhs);
+	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
+	mark_inode_dirty(dir);
+	inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
+	inode_dec_link_count(inode);
+	error = 0;
+
+out_brelse:
+	brelse(bh);
+	mutex_unlock(&info->bfs_lock);
+	return error;
+}
+
+static int bfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
+		      struct dentry *old_dentry, struct inode *new_dir,
+		      struct dentry *new_dentry, unsigned int flags)
+{
+	struct inode *old_inode, *new_inode;
+	struct buffer_head *old_bh, *new_bh;
+	struct bfs_dirent *old_de, *new_de;
+	struct bfs_sb_info *info;
+	int error = -ENOENT;
+
+	if (flags & ~RENAME_NOREPLACE)
+		return -EINVAL;
+
+	old_bh = new_bh = NULL;
+	old_inode = d_inode(old_dentry);
+	if (S_ISDIR(old_inode->i_mode))
+		return -EINVAL;
+
+	info = BFS_SB(old_inode->i_sb);
+
+	mutex_lock(&info->bfs_lock);
+	old_bh = bfs_find_entry(old_dir, &old_dentry->d_name, &old_de);
+
+	if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
+		goto end_rename;
+
+	error = -EPERM;
+	new_inode = d_inode(new_dentry);
+	new_bh = bfs_find_entry(new_dir, &new_dentry->d_name, &new_de);
+
+	if (new_bh && !new_inode) {
+		brelse(new_bh);
+		new_bh = NULL;
+	}
+	if (!new_bh) {
+		error = bfs_add_entry(new_dir, &new_dentry->d_name,
+					old_inode->i_ino);
+		if (error)
+			goto end_rename;
+	}
+	old_de->ino = 0;
+	inode_set_mtime_to_ts(old_dir, inode_set_ctime_current(old_dir));
+	mark_inode_dirty(old_dir);
+	if (new_inode) {
+		inode_set_ctime_current(new_inode);
+		inode_dec_link_count(new_inode);
+	}
+	mmb_mark_buffer_dirty(old_bh, &BFS_I(old_dir)->i_metadata_bhs);
+	error = 0;
+
+end_rename:
+	mutex_unlock(&info->bfs_lock);
+	brelse(old_bh);
+	brelse(new_bh);
+	return error;
+}
+
+const struct inode_operations bfs_dir_inops = {
+	.create			= bfs_create,
+	.lookup			= bfs_lookup,
+	.link			= bfs_link,
+	.unlink			= bfs_unlink,
+	.rename			= bfs_rename,
+};
+
+static int bfs_add_entry(struct inode *dir, const struct qstr *child, int ino)
+{
+	const unsigned char *name = child->name;
+	int namelen = child->len;
+	struct buffer_head *bh;
+	struct bfs_dirent *de;
+	int block, sblock, eblock, off, pos;
+	int i;
+
+	dprintf("name=%s, namelen=%d\n", name, namelen);
+
+	sblock = BFS_I(dir)->i_sblock;
+	eblock = BFS_I(dir)->i_eblock;
+	for (block = sblock; block <= eblock; block++) {
+		bh = sb_bread(dir->i_sb, block);
+		if (!bh)
+			return -EIO;
+		for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
+			de = (struct bfs_dirent *)(bh->b_data + off);
+			if (!de->ino) {
+				pos = (block - sblock) * BFS_BSIZE + off;
+				if (pos >= dir->i_size) {
+					dir->i_size += BFS_DIRENT_SIZE;
+					inode_set_ctime_current(dir);
+				}
+				inode_set_mtime_to_ts(dir,
+						      inode_set_ctime_current(dir));
+				mark_inode_dirty(dir);
+				de->ino = cpu_to_le16((u16)ino);
+				for (i = 0; i < BFS_NAMELEN; i++)
+					de->name[i] =
+						(i < namelen) ? name[i] : 0;
+				mmb_mark_buffer_dirty(bh,
+						&BFS_I(dir)->i_metadata_bhs);
+				brelse(bh);
+				return 0;
+			}
+		}
+		brelse(bh);
+	}
+	return -ENOSPC;
+}
+
+static inline int bfs_namecmp(int len, const unsigned char *name,
+							const char *buffer)
+{
+	if ((len < BFS_NAMELEN) && buffer[len])
+		return 0;
+	return !memcmp(name, buffer, len);
+}
+
+static struct buffer_head *bfs_find_entry(struct inode *dir,
+			const struct qstr *child,
+			struct bfs_dirent **res_dir)
+{
+	unsigned long block = 0, offset = 0;
+	struct buffer_head *bh = NULL;
+	struct bfs_dirent *de;
+	const unsigned char *name = child->name;
+	int namelen = child->len;
+
+	*res_dir = NULL;
+	if (namelen > BFS_NAMELEN)
+		return NULL;
+
+	while (block * BFS_BSIZE + offset < dir->i_size) {
+		if (!bh) {
+			bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
+			if (!bh) {
+				block++;
+				continue;
+			}
+		}
+		de = (struct bfs_dirent *)(bh->b_data + offset);
+		offset += BFS_DIRENT_SIZE;
+		if (le16_to_cpu(de->ino) &&
+				bfs_namecmp(namelen, name, de->name)) {
+			*res_dir = de;
+			return bh;
+		}
+		if (offset < bh->b_size)
+			continue;
+		brelse(bh);
+		bh = NULL;
+		offset = 0;
+		block++;
+	}
+	brelse(bh);
+	return NULL;
+}
diff --git a/fs/bfs/file.c b/fs/bfs/file.c
new file mode 100644
index 000000000..d33d6bde9
--- /dev/null
+++ b/fs/bfs/file.c
@@ -0,0 +1,203 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *	fs/bfs/file.c
+ *	BFS file operations.
+ *	Copyright (C) 1999-2018 Tigran Aivazian <aivazian.tigran@gmail.com>
+ *
+ *	Make the file block allocation algorithm understand the size
+ *	of the underlying block device.
+ *	Copyright (C) 2007 Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/mpage.h>
+#include <linux/buffer_head.h>
+#include "bfs.h"
+
+#undef DEBUG
+
+#ifdef DEBUG
+#define dprintf(x...)	printf(x)
+#else
+#define dprintf(x...)
+#endif
+
+const struct file_operations bfs_file_operations = {
+	.llseek 	= generic_file_llseek,
+	.read_iter	= generic_file_read_iter,
+	.write_iter	= generic_file_write_iter,
+	.mmap_prepare	= generic_file_mmap_prepare,
+	.splice_read	= filemap_splice_read,
+};
+
+static int bfs_move_block(unsigned long from, unsigned long to,
+					struct super_block *sb)
+{
+	struct buffer_head *bh, *new;
+
+	bh = sb_bread(sb, from);
+	if (!bh)
+		return -EIO;
+	new = sb_getblk(sb, to);
+	memcpy(new->b_data, bh->b_data, bh->b_size);
+	mark_buffer_dirty(new);
+	bforget(bh);
+	brelse(new);
+	return 0;
+}
+
+static int bfs_move_blocks(struct super_block *sb, unsigned long start,
+				unsigned long end, unsigned long where)
+{
+	unsigned long i;
+
+	dprintf("%08lx-%08lx->%08lx\n", start, end, where);
+	for (i = start; i <= end; i++)
+		if(bfs_move_block(i, where + i, sb)) {
+			dprintf("failed to move block %08lx -> %08lx\n", i,
+								where + i);
+			return -EIO;
+		}
+	return 0;
+}
+
+static int bfs_get_block(struct inode *inode, sector_t block,
+			struct buffer_head *bh_result, int create)
+{
+	unsigned long phys;
+	int err;
+	struct super_block *sb = inode->i_sb;
+	struct bfs_sb_info *info = BFS_SB(sb);
+	struct bfs_inode_info *bi = BFS_I(inode);
+
+	phys = bi->i_sblock + block;
+	if (!create) {
+		if (phys <= bi->i_eblock) {
+			dprintf("c=%d, b=%08lx, phys=%09lx (granted)\n",
+                                create, (unsigned long)block, phys);
+			map_bh(bh_result, sb, phys);
+		}
+		return 0;
+	}
+
+	/*
+	 * If the file is not empty and the requested block is within the
+	 * range of blocks allocated for this file, we can grant it.
+	 */
+	if (bi->i_sblock && (phys <= bi->i_eblock)) {
+		dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n", 
+				create, (unsigned long)block, phys);
+		map_bh(bh_result, sb, phys);
+		return 0;
+	}
+
+	/* The file will be extended, so let's see if there is enough space. */
+	if (phys >= info->si_blocks)
+		return -ENOSPC;
+
+	/* The rest has to be protected against itself. */
+	mutex_lock(&info->bfs_lock);
+
+	/*
+	 * If the last data block for this file is the last allocated
+	 * block, we can extend the file trivially, without moving it
+	 * anywhere.
+	 */
+	if (bi->i_eblock == info->si_lf_eblk) {
+		dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n", 
+				create, (unsigned long)block, phys);
+		map_bh(bh_result, sb, phys);
+		info->si_freeb -= phys - bi->i_eblock;
+		info->si_lf_eblk = bi->i_eblock = phys;
+		mark_inode_dirty(inode);
+		err = 0;
+		goto out;
+	}
+
+	/* Ok, we have to move this entire file to the next free block. */
+	phys = info->si_lf_eblk + 1;
+	if (phys + block >= info->si_blocks) {
+		err = -ENOSPC;
+		goto out;
+	}
+
+	if (bi->i_sblock) {
+		err = bfs_move_blocks(inode->i_sb, bi->i_sblock, 
+						bi->i_eblock, phys);
+		if (err) {
+			dprintf("failed to move ino=%08lx -> fs corruption\n",
+								inode->i_ino);
+			goto out;
+		}
+	} else
+		err = 0;
+
+	dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n",
+                create, (unsigned long)block, phys);
+	bi->i_sblock = phys;
+	phys += block;
+	info->si_lf_eblk = bi->i_eblock = phys;
+
+	/*
+	 * This assumes nothing can write the inode back while we are here
+	 * and thus update inode->i_blocks! (XXX)
+	 */
+	info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks;
+	mark_inode_dirty(inode);
+	map_bh(bh_result, sb, phys);
+out:
+	mutex_unlock(&info->bfs_lock);
+	return err;
+}
+
+static int bfs_writepages(struct address_space *mapping,
+		struct writeback_control *wbc)
+{
+	return mpage_writepages(mapping, wbc, bfs_get_block);
+}
+
+static int bfs_read_folio(struct file *file, struct folio *folio)
+{
+	return block_read_full_folio(folio, bfs_get_block);
+}
+
+static void bfs_write_failed(struct address_space *mapping, loff_t to)
+{
+	struct inode *inode = mapping->host;
+
+	if (to > inode->i_size)
+		truncate_pagecache(inode, inode->i_size);
+}
+
+static int bfs_write_begin(const struct kiocb *iocb,
+			   struct address_space *mapping,
+			   loff_t pos, unsigned len,
+			   struct folio **foliop, void **fsdata)
+{
+	int ret;
+
+	ret = block_write_begin(mapping, pos, len, foliop, bfs_get_block);
+	if (unlikely(ret))
+		bfs_write_failed(mapping, pos + len);
+
+	return ret;
+}
+
+static sector_t bfs_bmap(struct address_space *mapping, sector_t block)
+{
+	return generic_block_bmap(mapping, block, bfs_get_block);
+}
+
+const struct address_space_operations bfs_aops = {
+	.dirty_folio	= block_dirty_folio,
+	.invalidate_folio = block_invalidate_folio,
+	.read_folio	= bfs_read_folio,
+	.writepages	= bfs_writepages,
+	.write_begin	= bfs_write_begin,
+	.write_end	= generic_write_end,
+	.migrate_folio	= buffer_migrate_folio,
+	.bmap		= bfs_bmap,
+};
+
+const struct inode_operations bfs_file_inops;
diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c
new file mode 100644
index 000000000..06e3a848b
--- /dev/null
+++ b/fs/bfs/inode.c
@@ -0,0 +1,538 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *	fs/bfs/inode.c
+ *	BFS superblock and inode operations.
+ *	Copyright (C) 1999-2018 Tigran Aivazian <aivazian.tigran@gmail.com>
+ *	From fs/minix, Copyright (C) 1991, 1992 Linus Torvalds.
+ *	Made endianness-clean by Andrew Stribblehill <ads@wompom.org>, 2005.
+ */
+
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/vfs.h>
+#include <linux/writeback.h>
+#include <linux/uio.h>
+#include <linux/uaccess.h>
+#include <linux/fs_context.h>
+#include "bfs.h"
+
+MODULE_AUTHOR("Tigran Aivazian <aivazian.tigran@gmail.com>");
+MODULE_DESCRIPTION("SCO UnixWare BFS filesystem for Linux");
+MODULE_LICENSE("GPL");
+
+#undef DEBUG
+
+#ifdef DEBUG
+#define dprintf(x...)	printf(x)
+#else
+#define dprintf(x...)
+#endif
+
+struct inode *bfs_iget(struct super_block *sb, unsigned long ino)
+{
+	struct bfs_inode *di;
+	struct inode *inode;
+	struct buffer_head *bh;
+	int block, off;
+
+	inode = iget_locked(sb, ino);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode_state_read_once(inode) & I_NEW))
+		return inode;
+
+	if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(inode->i_sb)->si_lasti)) {
+		printf("Bad inode number %s:%08lx\n", inode->i_sb->s_id, ino);
+		goto error;
+	}
+
+	block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
+	bh = sb_bread(inode->i_sb, block);
+	if (!bh) {
+		printf("Unable to read inode %s:%08lx\n", inode->i_sb->s_id,
+									ino);
+		goto error;
+	}
+
+	off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
+	di = (struct bfs_inode *)bh->b_data + off;
+
+	/*
+	 * https://martin.hinner.info/fs/bfs/bfs-structure.html explains that
+	 * BFS in SCO UnixWare environment used only lower 9 bits of di->i_mode
+	 * value. This means that, although bfs_write_inode() saves whole
+	 * inode->i_mode bits (which include S_IFMT bits and S_IS{UID,GID,VTX}
+	 * bits), middle 7 bits of di->i_mode value can be garbage when these
+	 * bits were not saved by bfs_write_inode().
+	 * Since we can't tell whether middle 7 bits are garbage, use only
+	 * lower 12 bits (i.e. tolerate S_IS{UID,GID,VTX} bits possibly being
+	 * garbage) and reconstruct S_IFMT bits for Linux environment from
+	 * di->i_vtype value.
+	 */
+	inode->i_mode = 0x00000FFF & le32_to_cpu(di->i_mode);
+	if (le32_to_cpu(di->i_vtype) == BFS_VDIR) {
+		inode->i_mode |= S_IFDIR;
+		inode->i_op = &bfs_dir_inops;
+		inode->i_fop = &bfs_dir_operations;
+	} else if (le32_to_cpu(di->i_vtype) == BFS_VREG) {
+		inode->i_mode |= S_IFREG;
+		inode->i_op = &bfs_file_inops;
+		inode->i_fop = &bfs_file_operations;
+		inode->i_mapping->a_ops = &bfs_aops;
+	} else {
+		brelse(bh);
+		printf("Unknown vtype=%u %s:%08lx\n",
+		       le32_to_cpu(di->i_vtype), inode->i_sb->s_id, ino);
+		goto error;
+	}
+
+	BFS_I(inode)->i_sblock =  le32_to_cpu(di->i_sblock);
+	BFS_I(inode)->i_eblock =  le32_to_cpu(di->i_eblock);
+	BFS_I(inode)->i_dsk_ino = le16_to_cpu(di->i_ino);
+	i_uid_write(inode, le32_to_cpu(di->i_uid));
+	i_gid_write(inode,  le32_to_cpu(di->i_gid));
+	set_nlink(inode, le32_to_cpu(di->i_nlink));
+	inode->i_size = BFS_FILESIZE(di);
+	inode->i_blocks = BFS_FILEBLOCKS(di);
+	inode_set_atime(inode, le32_to_cpu(di->i_atime), 0);
+	inode_set_mtime(inode, le32_to_cpu(di->i_mtime), 0);
+	inode_set_ctime(inode, le32_to_cpu(di->i_ctime), 0);
+
+	brelse(bh);
+	unlock_new_inode(inode);
+	return inode;
+
+error:
+	iget_failed(inode);
+	return ERR_PTR(-EIO);
+}
+
+static struct bfs_inode *find_inode(struct super_block *sb, u16 ino, struct buffer_head **p)
+{
+	if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(sb)->si_lasti)) {
+		printf("Bad inode number %s:%08x\n", sb->s_id, ino);
+		return ERR_PTR(-EIO);
+	}
+
+	ino -= BFS_ROOT_INO;
+
+	*p = sb_bread(sb, 1 + ino / BFS_INODES_PER_BLOCK);
+	if (!*p) {
+		printf("Unable to read inode %s:%08x\n", sb->s_id, ino);
+		return ERR_PTR(-EIO);
+	}
+
+	return (struct bfs_inode *)(*p)->b_data +  ino % BFS_INODES_PER_BLOCK;
+}
+
+static int bfs_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
+	unsigned int ino = (u16)inode->i_ino;
+	unsigned long i_sblock;
+	struct bfs_inode *di;
+	struct buffer_head *bh;
+
+	dprintf("ino=%08x\n", ino);
+
+	di = find_inode(inode->i_sb, ino, &bh);
+	if (IS_ERR(di))
+		return PTR_ERR(di);
+
+	mutex_lock(&info->bfs_lock);
+
+	if (ino == BFS_ROOT_INO)
+		di->i_vtype = cpu_to_le32(BFS_VDIR);
+	else
+		di->i_vtype = cpu_to_le32(BFS_VREG);
+
+	di->i_ino = cpu_to_le16(ino);
+	di->i_mode = cpu_to_le32(inode->i_mode);
+	di->i_uid = cpu_to_le32(i_uid_read(inode));
+	di->i_gid = cpu_to_le32(i_gid_read(inode));
+	di->i_nlink = cpu_to_le32(inode->i_nlink);
+	di->i_atime = cpu_to_le32(inode_get_atime_sec(inode));
+	di->i_mtime = cpu_to_le32(inode_get_mtime_sec(inode));
+	di->i_ctime = cpu_to_le32(inode_get_ctime_sec(inode));
+	i_sblock = BFS_I(inode)->i_sblock;
+	di->i_sblock = cpu_to_le32(i_sblock);
+	di->i_eblock = cpu_to_le32(BFS_I(inode)->i_eblock);
+	di->i_eoffset = cpu_to_le32(i_sblock * BFS_BSIZE + inode->i_size - 1);
+
+	mark_buffer_dirty(bh);
+	brelse(bh);
+	mutex_unlock(&info->bfs_lock);
+	set_inode_metadata_writeback(inode);
+	return 0;
+}
+
+static int bfs_sync_inode_metadata(struct inode *inode,
+				   struct writeback_control *wbc)
+{
+	int err = 0;
+	struct bfs_inode *di;
+	struct buffer_head *bh;
+
+	di = find_inode(inode->i_sb, (u16)inode->i_ino, &bh);
+	if (IS_ERR(di))
+		return PTR_ERR(di);
+
+	sync_dirty_buffer(bh);
+	if (buffer_write_io_error(bh)) {
+		err = -EIO;
+		goto out;
+	}
+	err = mmb_sync(&BFS_I(inode)->i_metadata_bhs);
+out:
+	brelse(bh);
+	return err;
+}
+
+static void bfs_evict_inode(struct inode *inode)
+{
+	unsigned long ino = inode->i_ino;
+	struct bfs_inode *di;
+	struct buffer_head *bh;
+	struct super_block *s = inode->i_sb;
+	struct bfs_sb_info *info = BFS_SB(s);
+	struct bfs_inode_info *bi = BFS_I(inode);
+
+	dprintf("ino=%08lx\n", ino);
+
+	truncate_inode_pages_final(&inode->i_data);
+	if (inode->i_nlink)
+		mmb_sync(&BFS_I(inode)->i_metadata_bhs);
+	mmb_invalidate(&BFS_I(inode)->i_metadata_bhs);
+	clear_inode(inode);
+
+	if (inode->i_nlink)
+		return;
+
+	di = find_inode(s, inode->i_ino, &bh);
+	if (IS_ERR(di))
+		return;
+
+	mutex_lock(&info->bfs_lock);
+	/* clear on-disk inode */
+	memset(di, 0, sizeof(struct bfs_inode));
+	mark_buffer_dirty(bh);
+	brelse(bh);
+
+	if (bi->i_dsk_ino) {
+		if (bi->i_sblock)
+			info->si_freeb += bi->i_eblock + 1 - bi->i_sblock;
+		info->si_freei++;
+		clear_bit(ino, info->si_imap);
+		bfs_dump_imap("evict_inode", s);
+	}
+
+	/*
+	 * If this was the last file, make the previous block
+	 * "last block of the last file" even if there is no
+	 * real file there, saves us 1 gap.
+	 */
+	if (info->si_lf_eblk == bi->i_eblock)
+		info->si_lf_eblk = bi->i_sblock - 1;
+	mutex_unlock(&info->bfs_lock);
+}
+
+static void bfs_put_super(struct super_block *s)
+{
+	struct bfs_sb_info *info = BFS_SB(s);
+
+	if (!info)
+		return;
+
+	mutex_destroy(&info->bfs_lock);
+	kfree(info);
+	s->s_fs_info = NULL;
+}
+
+static int bfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *s = dentry->d_sb;
+	struct bfs_sb_info *info = BFS_SB(s);
+	u64 id = huge_encode_dev(s->s_bdev->bd_dev);
+	buf->f_type = BFS_MAGIC;
+	buf->f_bsize = s->s_blocksize;
+	buf->f_blocks = info->si_blocks;
+	buf->f_bfree = buf->f_bavail = info->si_freeb;
+	buf->f_files = info->si_lasti + 1 - BFS_ROOT_INO;
+	buf->f_ffree = info->si_freei;
+	buf->f_fsid = u64_to_fsid(id);
+	buf->f_namelen = BFS_NAMELEN;
+	return 0;
+}
+
+static struct kmem_cache *bfs_inode_cachep;
+
+static struct inode *bfs_alloc_inode(struct super_block *sb)
+{
+	struct bfs_inode_info *bi;
+	bi = alloc_inode_sb(sb, bfs_inode_cachep, GFP_KERNEL);
+	if (!bi)
+		return NULL;
+	mmb_init(&bi->i_metadata_bhs, &bi->vfs_inode.i_data);
+
+	return &bi->vfs_inode;
+}
+
+static void bfs_free_inode(struct inode *inode)
+{
+	kmem_cache_free(bfs_inode_cachep, BFS_I(inode));
+}
+
+static void init_once(void *foo)
+{
+	struct bfs_inode_info *bi = foo;
+
+	inode_init_once(&bi->vfs_inode);
+}
+
+static int __init init_inodecache(void)
+{
+	bfs_inode_cachep = kmem_cache_create("bfs_inode_cache",
+					     sizeof(struct bfs_inode_info),
+					     0, (SLAB_RECLAIM_ACCOUNT|
+						SLAB_ACCOUNT),
+					     init_once);
+	if (bfs_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(bfs_inode_cachep);
+}
+
+static const struct super_operations bfs_sops = {
+	.alloc_inode	= bfs_alloc_inode,
+	.free_inode	= bfs_free_inode,
+	.write_inode	= bfs_write_inode,
+	.sync_inode_metadata = bfs_sync_inode_metadata,
+	.evict_inode	= bfs_evict_inode,
+	.put_super	= bfs_put_super,
+	.statfs		= bfs_statfs,
+};
+
+void bfs_dump_imap(const char *prefix, struct super_block *s)
+{
+#ifdef DEBUG
+	int i;
+	char *tmpbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
+
+	if (!tmpbuf)
+		return;
+	for (i = BFS_SB(s)->si_lasti; i >= 0; i--) {
+		if (i > PAGE_SIZE - 100) break;
+		if (test_bit(i, BFS_SB(s)->si_imap))
+			strcat(tmpbuf, "1");
+		else
+			strcat(tmpbuf, "0");
+	}
+	printf("%s: lasti=%08lx <%s>\n", prefix, BFS_SB(s)->si_lasti, tmpbuf);
+	kfree(tmpbuf);
+#endif
+}
+
+static int bfs_fill_super(struct super_block *s, struct fs_context *fc)
+{
+	struct buffer_head *bh, *sbh;
+	struct bfs_super_block *bfs_sb;
+	struct inode *inode;
+	unsigned i;
+	struct bfs_sb_info *info;
+	int ret = -EINVAL;
+	unsigned long i_sblock, i_eblock, i_eoff, s_size;
+	int silent = fc->sb_flags & SB_SILENT;
+
+	info = kzalloc_obj(*info);
+	if (!info)
+		return -ENOMEM;
+	mutex_init(&info->bfs_lock);
+	s->s_fs_info = info;
+	s->s_time_min = 0;
+	s->s_time_max = U32_MAX;
+
+	if (!sb_set_blocksize(s, BFS_BSIZE))
+		goto out;
+
+	sbh = sb_bread(s, 0);
+	if (!sbh)
+		goto out;
+	bfs_sb = (struct bfs_super_block *)sbh->b_data;
+	if (le32_to_cpu(bfs_sb->s_magic) != BFS_MAGIC) {
+		if (!silent)
+			printf("No BFS filesystem on %s (magic=%08x)\n", s->s_id,  le32_to_cpu(bfs_sb->s_magic));
+		goto out1;
+	}
+	if (BFS_UNCLEAN(bfs_sb, s) && !silent)
+		printf("%s is unclean, continuing\n", s->s_id);
+
+	s->s_magic = BFS_MAGIC;
+
+	if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end) ||
+	    le32_to_cpu(bfs_sb->s_start) < sizeof(struct bfs_super_block) + sizeof(struct bfs_dirent)) {
+		printf("Superblock is corrupted on %s\n", s->s_id);
+		goto out1;
+	}
+
+	info->si_lasti = (le32_to_cpu(bfs_sb->s_start) - BFS_BSIZE) / sizeof(struct bfs_inode) + BFS_ROOT_INO - 1;
+	if (info->si_lasti == BFS_MAX_LASTI)
+		printf("NOTE: filesystem %s was created with 512 inodes, the real maximum is 511, mounting anyway\n", s->s_id);
+	else if (info->si_lasti > BFS_MAX_LASTI) {
+		printf("Impossible last inode number %lu > %d on %s\n", info->si_lasti, BFS_MAX_LASTI, s->s_id);
+		goto out1;
+	}
+	for (i = 0; i < BFS_ROOT_INO; i++)
+		set_bit(i, info->si_imap);
+
+	s->s_op = &bfs_sops;
+	inode = bfs_iget(s, BFS_ROOT_INO);
+	if (IS_ERR(inode)) {
+		ret = PTR_ERR(inode);
+		goto out1;
+	}
+	s->s_root = d_make_root(inode);
+	if (!s->s_root) {
+		ret = -ENOMEM;
+		goto out1;
+	}
+
+	info->si_blocks = (le32_to_cpu(bfs_sb->s_end) + 1) >> BFS_BSIZE_BITS;
+	info->si_freeb = (le32_to_cpu(bfs_sb->s_end) + 1 - le32_to_cpu(bfs_sb->s_start)) >> BFS_BSIZE_BITS;
+	info->si_freei = 0;
+	info->si_lf_eblk = 0;
+
+	/* can we read the last block? */
+	bh = sb_bread(s, info->si_blocks - 1);
+	if (!bh) {
+		printf("Last block not available on %s: %lu\n", s->s_id, info->si_blocks - 1);
+		ret = -EIO;
+		goto out2;
+	}
+	brelse(bh);
+
+	bh = NULL;
+	for (i = BFS_ROOT_INO; i <= info->si_lasti; i++) {
+		struct bfs_inode *di;
+		int block = (i - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
+		int off = (i - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
+		unsigned long eblock;
+
+		if (!off) {
+			brelse(bh);
+			bh = sb_bread(s, block);
+		}
+
+		if (!bh)
+			continue;
+
+		di = (struct bfs_inode *)bh->b_data + off;
+
+		/* test if filesystem is not corrupted */
+
+		i_eoff = le32_to_cpu(di->i_eoffset);
+		i_sblock = le32_to_cpu(di->i_sblock);
+		i_eblock = le32_to_cpu(di->i_eblock);
+		s_size = le32_to_cpu(bfs_sb->s_end);
+
+		if (i_sblock > info->si_blocks ||
+			i_eblock > info->si_blocks ||
+			i_sblock > i_eblock ||
+			(i_eoff != le32_to_cpu(-1) && i_eoff > s_size) ||
+			i_sblock * BFS_BSIZE > i_eoff) {
+
+			printf("Inode 0x%08x corrupted on %s\n", i, s->s_id);
+
+			brelse(bh);
+			ret = -EIO;
+			goto out2;
+		}
+
+		if (!di->i_ino) {
+			info->si_freei++;
+			continue;
+		}
+		set_bit(i, info->si_imap);
+		info->si_freeb -= BFS_FILEBLOCKS(di);
+
+		eblock =  le32_to_cpu(di->i_eblock);
+		if (eblock > info->si_lf_eblk)
+			info->si_lf_eblk = eblock;
+	}
+	brelse(bh);
+	brelse(sbh);
+	bfs_dump_imap("fill_super", s);
+	return 0;
+
+out2:
+	dput(s->s_root);
+	s->s_root = NULL;
+out1:
+	brelse(sbh);
+out:
+	mutex_destroy(&info->bfs_lock);
+	kfree(info);
+	s->s_fs_info = NULL;
+	return ret;
+}
+
+static int bfs_get_tree(struct fs_context *fc)
+{
+	return get_tree_bdev(fc, bfs_fill_super);
+}
+
+static const struct fs_context_operations bfs_context_ops = {
+	.get_tree = bfs_get_tree,
+};
+
+static int bfs_init_fs_context(struct fs_context *fc)
+{
+	fc->ops = &bfs_context_ops;
+
+	return 0;
+}
+
+static struct file_system_type bfs_fs_type = {
+	.owner			= THIS_MODULE,
+	.name			= "bfs",
+	.init_fs_context	= bfs_init_fs_context,
+	.kill_sb		= kill_block_super,
+	.fs_flags		= FS_REQUIRES_DEV,
+};
+MODULE_ALIAS_FS("bfs");
+
+static int __init init_bfs_fs(void)
+{
+	int err = init_inodecache();
+	if (err)
+		goto out1;
+	err = register_filesystem(&bfs_fs_type);
+	if (err)
+		goto out;
+	return 0;
+out:
+	destroy_inodecache();
+out1:
+	return err;
+}
+
+static void __exit exit_bfs_fs(void)
+{
+	unregister_filesystem(&bfs_fs_type);
+	destroy_inodecache();
+}
+
+module_init(init_bfs_fs)
+module_exit(exit_bfs_fs)