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
  ...

8 files changed, 1871 insertions, 0 deletions

diff --git a/fs/omfs/Kconfig b/fs/omfs/Kconfig
new file mode 100644
index 000000000..8470f6c3e
--- /dev/null
+++ b/fs/omfs/Kconfig
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config OMFS_FS
+	tristate "SonicBlue Optimized MPEG File System support"
+	depends on BLOCK
+	select BUFFER_HEAD
+	select CRC_ITU_T
+	help
+	  This is the proprietary file system used by the Rio Karma music
+	  player and ReplayTV DVR.  Despite the name, this filesystem is not
+	  more efficient than a standard FS for MPEG files, in fact likely
+	  the opposite is true.  Say Y if you have either of these devices
+	  and wish to mount its disk.
+
+	  To compile this file system support as a module, choose M here: the
+	  module will be called omfs.  If unsure, say N.
diff --git a/fs/omfs/Makefile b/fs/omfs/Makefile
new file mode 100644
index 000000000..ae16fc3d3
--- /dev/null
+++ b/fs/omfs/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_OMFS_FS) += omfs.o
+
+omfs-y := bitmap.o dir.o file.o inode.o
diff --git a/fs/omfs/bitmap.c b/fs/omfs/bitmap.c
new file mode 100644
index 000000000..7147ba6a6
--- /dev/null
+++ b/fs/omfs/bitmap.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <asm/div64.h>
+#include "omfs.h"
+
+unsigned long omfs_count_free(struct super_block *sb)
+{
+	unsigned int i;
+	unsigned long sum = 0;
+	struct omfs_sb_info *sbi = OMFS_SB(sb);
+	int nbits = sb->s_blocksize * 8;
+
+	for (i = 0; i < sbi->s_imap_size; i++)
+		sum += nbits - bitmap_weight(sbi->s_imap[i], nbits);
+
+	return sum;
+}
+
+/*
+ *  Counts the run of zero bits starting at bit up to max.
+ *  It handles the case where a run might spill over a buffer.
+ *  Called with bitmap lock.
+ */
+static int count_run(unsigned long **addr, int nbits,
+		int addrlen, int bit, int max)
+{
+	int count = 0;
+	int x;
+
+	for (; addrlen > 0; addrlen--, addr++) {
+		x = find_next_bit(*addr, nbits, bit);
+		count += x - bit;
+
+		if (x < nbits || count > max)
+			return min(count, max);
+
+		bit = 0;
+	}
+	return min(count, max);
+}
+
+/*
+ * Sets or clears the run of count bits starting with bit.
+ * Called with bitmap lock.
+ */
+static int set_run(struct super_block *sb, int map,
+		int nbits, int bit, int count, int set)
+{
+	int i;
+	int err;
+	struct buffer_head *bh;
+	struct omfs_sb_info *sbi = OMFS_SB(sb);
+
+ 	err = -ENOMEM;
+	bh = sb_bread(sb, clus_to_blk(sbi, sbi->s_bitmap_ino) + map);
+	if (!bh)
+		goto out;
+
+	for (i = 0; i < count; i++, bit++) {
+		if (bit >= nbits) {
+			bit = 0;
+			map++;
+
+			mark_buffer_dirty(bh);
+			brelse(bh);
+			bh = sb_bread(sb,
+				clus_to_blk(sbi, sbi->s_bitmap_ino) + map);
+			if (!bh)
+				goto out;
+		}
+		if (set) {
+			set_bit(bit, sbi->s_imap[map]);
+			set_bit(bit, (unsigned long *)bh->b_data);
+		} else {
+			clear_bit(bit, sbi->s_imap[map]);
+			clear_bit(bit, (unsigned long *)bh->b_data);
+		}
+	}
+	mark_buffer_dirty(bh);
+	brelse(bh);
+	err = 0;
+out:
+	return err;
+}
+
+/*
+ * Tries to allocate exactly one block.  Returns true if successful.
+ */
+int omfs_allocate_block(struct super_block *sb, u64 block)
+{
+	struct buffer_head *bh;
+	struct omfs_sb_info *sbi = OMFS_SB(sb);
+	int bits_per_entry = 8 * sb->s_blocksize;
+	unsigned int map, bit;
+	int ret = 0;
+	u64 tmp;
+
+	tmp = block;
+	bit = do_div(tmp, bits_per_entry);
+	map = tmp;
+
+	mutex_lock(&sbi->s_bitmap_lock);
+	if (map >= sbi->s_imap_size || test_and_set_bit(bit, sbi->s_imap[map]))
+		goto out;
+
+	if (sbi->s_bitmap_ino > 0) {
+		bh = sb_bread(sb, clus_to_blk(sbi, sbi->s_bitmap_ino) + map);
+		if (!bh)
+			goto out;
+
+		set_bit(bit, (unsigned long *)bh->b_data);
+		mark_buffer_dirty(bh);
+		brelse(bh);
+	}
+	ret = 1;
+out:
+	mutex_unlock(&sbi->s_bitmap_lock);
+	return ret;
+}
+
+
+/*
+ *  Tries to allocate a set of blocks.	The request size depends on the
+ *  type: for inodes, we must allocate sbi->s_mirrors blocks, and for file
+ *  blocks, we try to allocate sbi->s_clustersize, but can always get away
+ *  with just one block.
+ */
+int omfs_allocate_range(struct super_block *sb,
+			int min_request,
+			int max_request,
+			u64 *return_block,
+			int *return_size)
+{
+	struct omfs_sb_info *sbi = OMFS_SB(sb);
+	int bits_per_entry = 8 * sb->s_blocksize;
+	int ret = 0;
+	int i, run, bit;
+
+	mutex_lock(&sbi->s_bitmap_lock);
+	for (i = 0; i < sbi->s_imap_size; i++) {
+		bit = 0;
+		while (bit < bits_per_entry) {
+			bit = find_next_zero_bit(sbi->s_imap[i], bits_per_entry,
+				bit);
+
+			if (bit == bits_per_entry)
+				break;
+
+			run = count_run(&sbi->s_imap[i], bits_per_entry,
+				sbi->s_imap_size-i, bit, max_request);
+
+			if (run >= min_request)
+				goto found;
+			bit += run;
+		}
+	}
+	ret = -ENOSPC;
+	goto out;
+
+found:
+	*return_block = (u64) i * bits_per_entry + bit;
+	*return_size = run;
+	ret = set_run(sb, i, bits_per_entry, bit, run, 1);
+
+out:
+	mutex_unlock(&sbi->s_bitmap_lock);
+	return ret;
+}
+
+/*
+ * Clears count bits starting at a given block.
+ */
+int omfs_clear_range(struct super_block *sb, u64 block, int count)
+{
+	struct omfs_sb_info *sbi = OMFS_SB(sb);
+	int bits_per_entry = 8 * sb->s_blocksize;
+	u64 tmp;
+	unsigned int map, bit;
+	int ret;
+
+	tmp = block;
+	bit = do_div(tmp, bits_per_entry);
+	map = tmp;
+
+	if (map >= sbi->s_imap_size)
+		return 0;
+
+	mutex_lock(&sbi->s_bitmap_lock);
+	ret = set_run(sb, map, bits_per_entry, bit, count, 0);
+	mutex_unlock(&sbi->s_bitmap_lock);
+	return ret;
+}
diff --git a/fs/omfs/dir.c b/fs/omfs/dir.c
new file mode 100644
index 000000000..692297cf8
--- /dev/null
+++ b/fs/omfs/dir.c
@@ -0,0 +1,461 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * OMFS (as used by RIO Karma) directory operations.
+ * Copyright (C) 2005 Bob Copeland <me@bobcopeland.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/ctype.h>
+#include <linux/buffer_head.h>
+#include "omfs.h"
+
+static int omfs_hash(const char *name, int namelen, int mod)
+{
+	int i, hash = 0;
+	for (i = 0; i < namelen; i++)
+		hash ^= tolower(name[i]) << (i % 24);
+	return hash % mod;
+}
+
+/*
+ * Finds the bucket for a given name and reads the containing block;
+ * *ofs is set to the offset of the first list entry.
+ */
+static struct buffer_head *omfs_get_bucket(struct inode *dir,
+		const char *name, int namelen, int *ofs)
+{
+	int nbuckets = (dir->i_size - OMFS_DIR_START)/8;
+	int bucket = omfs_hash(name, namelen, nbuckets);
+
+	*ofs = OMFS_DIR_START + bucket * 8;
+	return omfs_bread(dir->i_sb, dir->i_ino);
+}
+
+static struct buffer_head *omfs_scan_list(struct inode *dir, u64 block,
+				const char *name, int namelen,
+				u64 *prev_block)
+{
+	struct buffer_head *bh;
+	struct omfs_inode *oi;
+	int err = -ENOENT;
+	*prev_block = ~0;
+
+	while (block != ~0) {
+		bh = omfs_bread(dir->i_sb, block);
+		if (!bh) {
+			err = -EIO;
+			goto err;
+		}
+
+		oi = (struct omfs_inode *) bh->b_data;
+		if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, block)) {
+			brelse(bh);
+			goto err;
+		}
+
+		if (strncmp(oi->i_name, name, namelen) == 0)
+			return bh;
+
+		*prev_block = block;
+		block = be64_to_cpu(oi->i_sibling);
+		brelse(bh);
+	}
+err:
+	return ERR_PTR(err);
+}
+
+static struct buffer_head *omfs_find_entry(struct inode *dir,
+					   const char *name, int namelen)
+{
+	struct buffer_head *bh;
+	int ofs;
+	u64 block, dummy;
+
+	bh = omfs_get_bucket(dir, name, namelen, &ofs);
+	if (!bh)
+		return ERR_PTR(-EIO);
+
+	block = be64_to_cpu(*((__be64 *) &bh->b_data[ofs]));
+	brelse(bh);
+
+	return omfs_scan_list(dir, block, name, namelen, &dummy);
+}
+
+int omfs_make_empty(struct inode *inode, struct super_block *sb)
+{
+	struct omfs_sb_info *sbi = OMFS_SB(sb);
+	struct buffer_head *bh;
+	struct omfs_inode *oi;
+
+	bh = omfs_bread(sb, inode->i_ino);
+	if (!bh)
+		return -ENOMEM;
+
+	memset(bh->b_data, 0, sizeof(struct omfs_inode));
+
+	if (S_ISDIR(inode->i_mode)) {
+		memset(&bh->b_data[OMFS_DIR_START], 0xff,
+			sbi->s_sys_blocksize - OMFS_DIR_START);
+	} else
+		omfs_make_empty_table(bh, OMFS_EXTENT_START);
+
+	oi = (struct omfs_inode *) bh->b_data;
+	oi->i_head.h_self = cpu_to_be64(inode->i_ino);
+	oi->i_sibling = ~cpu_to_be64(0ULL);
+
+	mark_buffer_dirty(bh);
+	brelse(bh);
+	return 0;
+}
+
+static int omfs_add_link(struct dentry *dentry, struct inode *inode)
+{
+	struct inode *dir = d_inode(dentry->d_parent);
+	const char *name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
+	struct omfs_inode *oi;
+	struct buffer_head *bh;
+	u64 block;
+	__be64 *entry;
+	int ofs;
+
+	/* just prepend to head of queue in proper bucket */
+	bh = omfs_get_bucket(dir, name, namelen, &ofs);
+	if (!bh)
+		goto out;
+
+	entry = (__be64 *) &bh->b_data[ofs];
+	block = be64_to_cpu(*entry);
+	*entry = cpu_to_be64(inode->i_ino);
+	mark_buffer_dirty(bh);
+	brelse(bh);
+
+	/* now set the sibling and parent pointers on the new inode */
+	bh = omfs_bread(dir->i_sb, inode->i_ino);
+	if (!bh)
+		goto out;
+
+	oi = (struct omfs_inode *) bh->b_data;
+	memcpy(oi->i_name, name, namelen);
+	memset(oi->i_name + namelen, 0, OMFS_NAMELEN - namelen);
+	oi->i_sibling = cpu_to_be64(block);
+	oi->i_parent = cpu_to_be64(dir->i_ino);
+	mark_buffer_dirty(bh);
+	brelse(bh);
+
+	inode_set_ctime_current(dir);
+
+	/* mark affected inodes dirty to rebuild checksums */
+	mark_inode_dirty(dir);
+	mark_inode_dirty(inode);
+	return 0;
+out:
+	return -ENOMEM;
+}
+
+static int omfs_delete_entry(struct dentry *dentry)
+{
+	struct inode *dir = d_inode(dentry->d_parent);
+	struct inode *dirty;
+	const char *name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
+	struct omfs_inode *oi;
+	struct buffer_head *bh, *bh2;
+	__be64 *entry, next;
+	u64 block, prev;
+	int ofs;
+	int err = -ENOMEM;
+
+	/* delete the proper node in the bucket's linked list */
+	bh = omfs_get_bucket(dir, name, namelen, &ofs);
+	if (!bh)
+		goto out;
+
+	entry = (__be64 *) &bh->b_data[ofs];
+	block = be64_to_cpu(*entry);
+
+	bh2 = omfs_scan_list(dir, block, name, namelen, &prev);
+	if (IS_ERR(bh2)) {
+		err = PTR_ERR(bh2);
+		goto out_free_bh;
+	}
+
+	oi = (struct omfs_inode *) bh2->b_data;
+	next = oi->i_sibling;
+	brelse(bh2);
+
+	if (prev != ~0) {
+		/* found in middle of list, get list ptr */
+		brelse(bh);
+		bh = omfs_bread(dir->i_sb, prev);
+		if (!bh)
+			goto out;
+
+		oi = (struct omfs_inode *) bh->b_data;
+		entry = &oi->i_sibling;
+	}
+
+	*entry = next;
+	mark_buffer_dirty(bh);
+
+	if (prev != ~0) {
+		dirty = omfs_iget(dir->i_sb, prev);
+		if (!IS_ERR(dirty)) {
+			mark_inode_dirty(dirty);
+			iput(dirty);
+		}
+	}
+
+	err = 0;
+out_free_bh:
+	brelse(bh);
+out:
+	return err;
+}
+
+static int omfs_dir_is_empty(struct inode *inode)
+{
+	int nbuckets = (inode->i_size - OMFS_DIR_START) / 8;
+	struct buffer_head *bh;
+	u64 *ptr;
+	int i;
+
+	bh = omfs_bread(inode->i_sb, inode->i_ino);
+
+	if (!bh)
+		return 0;
+
+	ptr = (u64 *) &bh->b_data[OMFS_DIR_START];
+
+	for (i = 0; i < nbuckets; i++, ptr++)
+		if (*ptr != ~0)
+			break;
+
+	brelse(bh);
+	return *ptr != ~0;
+}
+
+static int omfs_remove(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = d_inode(dentry);
+	int ret;
+
+
+	if (S_ISDIR(inode->i_mode) &&
+	    !omfs_dir_is_empty(inode))
+		return -ENOTEMPTY;
+
+	ret = omfs_delete_entry(dentry);
+	if (ret)
+		return ret;
+	
+	clear_nlink(inode);
+	mark_inode_dirty(inode);
+	mark_inode_dirty(dir);
+	return 0;
+}
+
+static int omfs_add_node(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+	int err;
+	struct inode *inode = omfs_new_inode(dir, mode);
+
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+
+	err = omfs_make_empty(inode, dir->i_sb);
+	if (err)
+		goto out_free_inode;
+
+	err = omfs_add_link(dentry, inode);
+	if (err)
+		goto out_free_inode;
+
+	d_instantiate(dentry, inode);
+	return 0;
+
+out_free_inode:
+	iput(inode);
+	return err;
+}
+
+static struct dentry *omfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
+				 struct dentry *dentry, umode_t mode)
+{
+	return ERR_PTR(omfs_add_node(dir, dentry, mode));
+}
+
+static int omfs_create(struct mnt_idmap *idmap, struct inode *dir,
+		       struct dentry *dentry, umode_t mode)
+{
+	return omfs_add_node(dir, dentry, mode | S_IFREG);
+}
+
+static struct dentry *omfs_lookup(struct inode *dir, struct dentry *dentry,
+				  unsigned int flags)
+{
+	struct buffer_head *bh;
+	struct inode *inode = NULL;
+
+	if (dentry->d_name.len > OMFS_NAMELEN)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	bh = omfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len);
+	if (!IS_ERR(bh)) {
+		struct omfs_inode *oi = (struct omfs_inode *)bh->b_data;
+		ino_t ino = be64_to_cpu(oi->i_head.h_self);
+		brelse(bh);
+		inode = omfs_iget(dir->i_sb, ino);
+	} else if (bh != ERR_PTR(-ENOENT)) {
+		inode = ERR_CAST(bh);
+	}
+	return d_splice_alias(inode, dentry);
+}
+
+/* sanity check block's self pointer */
+int omfs_is_bad(struct omfs_sb_info *sbi, struct omfs_header *header,
+	u64 fsblock)
+{
+	int is_bad;
+	u64 ino = be64_to_cpu(header->h_self);
+	is_bad = ((ino != fsblock) || (ino < sbi->s_root_ino) ||
+		(ino > sbi->s_num_blocks));
+
+	if (is_bad)
+		printk(KERN_WARNING "omfs: bad hash chain detected\n");
+
+	return is_bad;
+}
+
+static bool omfs_fill_chain(struct inode *dir, struct dir_context *ctx,
+		u64 fsblock, int hindex)
+{
+	/* follow chain in this bucket */
+	while (fsblock != ~0) {
+		struct buffer_head *bh = omfs_bread(dir->i_sb, fsblock);
+		struct omfs_inode *oi;
+		u64 self;
+		unsigned char d_type;
+
+		if (!bh)
+			return true;
+
+		oi = (struct omfs_inode *) bh->b_data;
+		if (omfs_is_bad(OMFS_SB(dir->i_sb), &oi->i_head, fsblock)) {
+			brelse(bh);
+			return true;
+		}
+
+		self = fsblock;
+		fsblock = be64_to_cpu(oi->i_sibling);
+
+		/* skip visited nodes */
+		if (hindex) {
+			hindex--;
+			brelse(bh);
+			continue;
+		}
+
+		d_type = (oi->i_type == OMFS_DIR) ? DT_DIR : DT_REG;
+
+		if (!dir_emit(ctx, oi->i_name,
+			      strnlen(oi->i_name, OMFS_NAMELEN),
+			      self, d_type)) {
+			brelse(bh);
+			return false;
+		}
+		brelse(bh);
+		ctx->pos++;
+	}
+	return true;
+}
+
+static int omfs_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 *new_inode = d_inode(new_dentry);
+	struct inode *old_inode = d_inode(old_dentry);
+	int err;
+
+	if (flags & ~RENAME_NOREPLACE)
+		return -EINVAL;
+
+	if (new_inode) {
+		/* overwriting existing file/dir */
+		err = omfs_remove(new_dir, new_dentry);
+		if (err)
+			goto out;
+	}
+
+	/* since omfs locates files by name, we need to unlink _before_
+	 * adding the new link or we won't find the old one */
+	err = omfs_delete_entry(old_dentry);
+	if (err)
+		goto out;
+
+	mark_inode_dirty(old_dir);
+	err = omfs_add_link(new_dentry, old_inode);
+	if (err)
+		goto out;
+
+	inode_set_ctime_current(old_inode);
+	mark_inode_dirty(old_inode);
+out:
+	return err;
+}
+
+static int omfs_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *dir = file_inode(file);
+	struct buffer_head *bh;
+	__be64 *p;
+	unsigned int hchain, hindex;
+	int nbuckets;
+
+	if (ctx->pos >> 32)
+		return -EINVAL;
+
+	if (ctx->pos < 1 << 20) {
+		if (!dir_emit_dots(file, ctx))
+			return 0;
+		ctx->pos = 1 << 20;
+	}
+
+	nbuckets = (dir->i_size - OMFS_DIR_START) / 8;
+
+	/* high 12 bits store bucket + 1 and low 20 bits store hash index */
+	hchain = (ctx->pos >> 20) - 1;
+	hindex = ctx->pos & 0xfffff;
+
+	bh = omfs_bread(dir->i_sb, dir->i_ino);
+	if (!bh)
+		return -EINVAL;
+
+	p = (__be64 *)(bh->b_data + OMFS_DIR_START) + hchain;
+
+	for (; hchain < nbuckets; hchain++) {
+		__u64 fsblock = be64_to_cpu(*p++);
+		if (!omfs_fill_chain(dir, ctx, fsblock, hindex))
+			break;
+		hindex = 0;
+		ctx->pos = (hchain+2) << 20;
+	}
+	brelse(bh);
+	return 0;
+}
+
+const struct inode_operations omfs_dir_inops = {
+	.lookup = omfs_lookup,
+	.mkdir = omfs_mkdir,
+	.rename = omfs_rename,
+	.create = omfs_create,
+	.unlink = omfs_remove,
+	.rmdir = omfs_remove,
+};
+
+const struct file_operations omfs_dir_operations = {
+	.read = generic_read_dir,
+	.iterate_shared = omfs_readdir,
+	.llseek = generic_file_llseek,
+};
diff --git a/fs/omfs/file.c b/fs/omfs/file.c
new file mode 100644
index 000000000..28f3b1133
--- /dev/null
+++ b/fs/omfs/file.c
@@ -0,0 +1,380 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * OMFS (as used by RIO Karma) file operations.
+ * Copyright (C) 2005 Bob Copeland <me@bobcopeland.com>
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/mpage.h>
+#include "omfs.h"
+
+static u32 omfs_max_extents(struct omfs_sb_info *sbi, int offset)
+{
+	return (sbi->s_sys_blocksize - offset -
+		sizeof(struct omfs_extent)) /
+		sizeof(struct omfs_extent_entry);
+}
+
+void omfs_make_empty_table(struct buffer_head *bh, int offset)
+{
+	struct omfs_extent *oe = (struct omfs_extent *) &bh->b_data[offset];
+
+	oe->e_next = ~cpu_to_be64(0ULL);
+	oe->e_extent_count = cpu_to_be32(1),
+	oe->e_fill = cpu_to_be32(0x22),
+	oe->e_entry[0].e_cluster = ~cpu_to_be64(0ULL);
+	oe->e_entry[0].e_blocks = ~cpu_to_be64(0ULL);
+}
+
+int omfs_shrink_inode(struct inode *inode)
+{
+	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
+	struct omfs_extent *oe;
+	struct omfs_extent_entry *entry;
+	struct buffer_head *bh;
+	u64 next, last;
+	u32 extent_count;
+	u32 max_extents;
+	int ret;
+
+	/* traverse extent table, freeing each entry that is greater
+	 * than inode->i_size;
+	 */
+	next = inode->i_ino;
+
+	/* only support truncate -> 0 for now */
+	ret = -EIO;
+	if (inode->i_size != 0)
+		goto out;
+
+	bh = omfs_bread(inode->i_sb, next);
+	if (!bh)
+		goto out;
+
+	oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]);
+	max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START);
+
+	for (;;) {
+
+		if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next))
+			goto out_brelse;
+
+		extent_count = be32_to_cpu(oe->e_extent_count);
+
+		if (extent_count > max_extents)
+			goto out_brelse;
+
+		last = next;
+		next = be64_to_cpu(oe->e_next);
+		entry = oe->e_entry;
+
+		/* ignore last entry as it is the terminator */
+		for (; extent_count > 1; extent_count--) {
+			u64 start, count;
+			start = be64_to_cpu(entry->e_cluster);
+			count = be64_to_cpu(entry->e_blocks);
+
+			omfs_clear_range(inode->i_sb, start, (int) count);
+			entry++;
+		}
+		omfs_make_empty_table(bh, (char *) oe - bh->b_data);
+		mark_buffer_dirty(bh);
+		brelse(bh);
+
+		if (last != inode->i_ino)
+			omfs_clear_range(inode->i_sb, last, sbi->s_mirrors);
+
+		if (next == ~0)
+			break;
+
+		bh = omfs_bread(inode->i_sb, next);
+		if (!bh)
+			goto out;
+		oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);
+		max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT);
+	}
+	ret = 0;
+out:
+	return ret;
+out_brelse:
+	brelse(bh);
+	return ret;
+}
+
+static void omfs_truncate(struct inode *inode)
+{
+	omfs_shrink_inode(inode);
+	mark_inode_dirty(inode);
+}
+
+/*
+ * Add new blocks to the current extent, or create new entries/continuations
+ * as necessary.
+ */
+static int omfs_grow_extent(struct inode *inode, struct omfs_extent *oe,
+			u64 *ret_block)
+{
+	struct omfs_extent_entry *terminator;
+	struct omfs_extent_entry *entry = oe->e_entry;
+	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
+	u32 extent_count = be32_to_cpu(oe->e_extent_count);
+	u64 new_block = 0;
+	u32 max_count;
+	int new_count;
+	int ret = 0;
+
+	/* reached the end of the extent table with no blocks mapped.
+	 * there are three possibilities for adding: grow last extent,
+	 * add a new extent to the current extent table, and add a
+	 * continuation inode.  in last two cases need an allocator for
+	 * sbi->s_cluster_size
+	 */
+
+	/* TODO: handle holes */
+
+	/* should always have a terminator */
+	if (extent_count < 1)
+		return -EIO;
+
+	/* trivially grow current extent, if next block is not taken */
+	terminator = entry + extent_count - 1;
+	if (extent_count > 1) {
+		entry = terminator-1;
+		new_block = be64_to_cpu(entry->e_cluster) +
+			be64_to_cpu(entry->e_blocks);
+
+		if (omfs_allocate_block(inode->i_sb, new_block)) {
+			be64_add_cpu(&entry->e_blocks, 1);
+			terminator->e_blocks = ~(cpu_to_be64(
+				be64_to_cpu(~terminator->e_blocks) + 1));
+			goto out;
+		}
+	}
+	max_count = omfs_max_extents(sbi, OMFS_EXTENT_START);
+
+	/* TODO: add a continuation block here */
+	if (be32_to_cpu(oe->e_extent_count) > max_count-1)
+		return -EIO;
+
+	/* try to allocate a new cluster */
+	ret = omfs_allocate_range(inode->i_sb, 1, sbi->s_clustersize,
+		&new_block, &new_count);
+	if (ret)
+		goto out_fail;
+
+	/* copy terminator down an entry */
+	entry = terminator;
+	terminator++;
+	memcpy(terminator, entry, sizeof(struct omfs_extent_entry));
+
+	entry->e_cluster = cpu_to_be64(new_block);
+	entry->e_blocks = cpu_to_be64((u64) new_count);
+
+	terminator->e_blocks = ~(cpu_to_be64(
+		be64_to_cpu(~terminator->e_blocks) + (u64) new_count));
+
+	/* write in new entry */
+	be32_add_cpu(&oe->e_extent_count, 1);
+
+out:
+	*ret_block = new_block;
+out_fail:
+	return ret;
+}
+
+/*
+ * Scans across the directory table for a given file block number.
+ * If block not found, return 0.
+ */
+static sector_t find_block(struct inode *inode, struct omfs_extent_entry *ent,
+			sector_t block, int count, int *left)
+{
+	/* count > 1 because of terminator */
+	sector_t searched = 0;
+	for (; count > 1; count--) {
+		int numblocks = clus_to_blk(OMFS_SB(inode->i_sb),
+			be64_to_cpu(ent->e_blocks));
+
+		if (block >= searched  &&
+		    block < searched + numblocks) {
+			/*
+			 * found it at cluster + (block - searched)
+			 * numblocks - (block - searched) is remainder
+			 */
+			*left = numblocks - (block - searched);
+			return clus_to_blk(OMFS_SB(inode->i_sb),
+				be64_to_cpu(ent->e_cluster)) +
+				block - searched;
+		}
+		searched += numblocks;
+		ent++;
+	}
+	return 0;
+}
+
+static int omfs_get_block(struct inode *inode, sector_t block,
+			  struct buffer_head *bh_result, int create)
+{
+	struct buffer_head *bh;
+	sector_t next, offset;
+	int ret;
+	u64 new_block;
+	u32 max_extents;
+	int extent_count;
+	struct omfs_extent *oe;
+	struct omfs_extent_entry *entry;
+	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
+	int max_blocks = bh_result->b_size >> inode->i_blkbits;
+	int remain;
+
+	ret = -EIO;
+	bh = omfs_bread(inode->i_sb, inode->i_ino);
+	if (!bh)
+		goto out;
+
+	oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]);
+	max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START);
+	next = inode->i_ino;
+
+	for (;;) {
+
+		if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next))
+			goto out_brelse;
+
+		extent_count = be32_to_cpu(oe->e_extent_count);
+		next = be64_to_cpu(oe->e_next);
+		entry = oe->e_entry;
+
+		if (extent_count > max_extents)
+			goto out_brelse;
+
+		offset = find_block(inode, entry, block, extent_count, &remain);
+		if (offset > 0) {
+			ret = 0;
+			map_bh(bh_result, inode->i_sb, offset);
+			if (remain > max_blocks)
+				remain = max_blocks;
+			bh_result->b_size = (remain << inode->i_blkbits);
+			goto out_brelse;
+		}
+		if (next == ~0)
+			break;
+
+		brelse(bh);
+		bh = omfs_bread(inode->i_sb, next);
+		if (!bh)
+			goto out;
+		oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);
+		max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT);
+	}
+	if (create) {
+		ret = omfs_grow_extent(inode, oe, &new_block);
+		if (ret == 0) {
+			mark_buffer_dirty(bh);
+			mark_inode_dirty(inode);
+			map_bh(bh_result, inode->i_sb,
+					clus_to_blk(sbi, new_block));
+		}
+	}
+out_brelse:
+	brelse(bh);
+out:
+	return ret;
+}
+
+static int omfs_read_folio(struct file *file, struct folio *folio)
+{
+	return block_read_full_folio(folio, omfs_get_block);
+}
+
+static void omfs_readahead(struct readahead_control *rac)
+{
+	mpage_readahead(rac, omfs_get_block);
+}
+
+static int
+omfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
+{
+	return mpage_writepages(mapping, wbc, omfs_get_block);
+}
+
+static void omfs_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);
+		omfs_truncate(inode);
+	}
+}
+
+static int omfs_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, omfs_get_block);
+	if (unlikely(ret))
+		omfs_write_failed(mapping, pos + len);
+
+	return ret;
+}
+
+static sector_t omfs_bmap(struct address_space *mapping, sector_t block)
+{
+	return generic_block_bmap(mapping, block, omfs_get_block);
+}
+
+const struct file_operations omfs_file_operations = {
+	.llseek = generic_file_llseek,
+	.read_iter = generic_file_read_iter,
+	.write_iter = generic_file_write_iter,
+	.mmap_prepare = generic_file_mmap_prepare,
+	.fsync = simple_fsync,
+	.splice_read = filemap_splice_read,
+};
+
+static int omfs_setattr(struct mnt_idmap *idmap,
+			struct dentry *dentry, struct iattr *attr)
+{
+	struct inode *inode = d_inode(dentry);
+	int error;
+
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
+	if (error)
+		return error;
+
+	if ((attr->ia_valid & ATTR_SIZE) &&
+	    attr->ia_size != i_size_read(inode)) {
+		error = inode_newsize_ok(inode, attr->ia_size);
+		if (error)
+			return error;
+		truncate_setsize(inode, attr->ia_size);
+		omfs_truncate(inode);
+	}
+
+	setattr_copy(&nop_mnt_idmap, inode, attr);
+	mark_inode_dirty(inode);
+	return 0;
+}
+
+const struct inode_operations omfs_file_inops = {
+	.setattr = omfs_setattr,
+};
+
+const struct address_space_operations omfs_aops = {
+	.dirty_folio = block_dirty_folio,
+	.invalidate_folio = block_invalidate_folio,
+	.read_folio = omfs_read_folio,
+	.readahead = omfs_readahead,
+	.writepages = omfs_writepages,
+	.write_begin = omfs_write_begin,
+	.write_end = generic_write_end,
+	.bmap = omfs_bmap,
+	.migrate_folio = buffer_migrate_folio,
+};
+
diff --git a/fs/omfs/inode.c b/fs/omfs/inode.c
new file mode 100644
index 000000000..1d915ef72
--- /dev/null
+++ b/fs/omfs/inode.c
@@ -0,0 +1,664 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Optimized MPEG FS - inode and super operations.
+ * Copyright (C) 2006 Bob Copeland <me@bobcopeland.com>
+ */
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/vfs.h>
+#include <linux/cred.h>
+#include <linux/buffer_head.h>
+#include <linux/vmalloc.h>
+#include <linux/writeback.h>
+#include <linux/seq_file.h>
+#include <linux/crc-itu-t.h>
+#include <linux/fs_struct.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include "omfs.h"
+
+MODULE_AUTHOR("Bob Copeland <me@bobcopeland.com>");
+MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");
+MODULE_LICENSE("GPL");
+
+struct buffer_head *omfs_bread(struct super_block *sb, sector_t block)
+{
+	struct omfs_sb_info *sbi = OMFS_SB(sb);
+	if (block >= sbi->s_num_blocks)
+		return NULL;
+
+	return sb_bread(sb, clus_to_blk(sbi, block));
+}
+
+struct inode *omfs_new_inode(struct inode *dir, umode_t mode)
+{
+	struct inode *inode;
+	u64 new_block;
+	int err;
+	int len;
+	struct omfs_sb_info *sbi = OMFS_SB(dir->i_sb);
+
+	inode = new_inode(dir->i_sb);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+
+	err = omfs_allocate_range(dir->i_sb, sbi->s_mirrors, sbi->s_mirrors,
+			&new_block, &len);
+	if (err)
+		goto fail;
+
+	inode->i_ino = new_block;
+	inode_init_owner(&nop_mnt_idmap, inode, NULL, mode);
+	inode->i_mapping->a_ops = &omfs_aops;
+
+	simple_inode_init_ts(inode);
+	switch (mode & S_IFMT) {
+	case S_IFDIR:
+		inode->i_op = &omfs_dir_inops;
+		inode->i_fop = &omfs_dir_operations;
+		inode->i_size = sbi->s_sys_blocksize;
+		inc_nlink(inode);
+		break;
+	case S_IFREG:
+		inode->i_op = &omfs_file_inops;
+		inode->i_fop = &omfs_file_operations;
+		inode->i_size = 0;
+		break;
+	}
+
+	insert_inode_hash(inode);
+	mark_inode_dirty(inode);
+	return inode;
+fail:
+	make_bad_inode(inode);
+	iput(inode);
+	return ERR_PTR(err);
+}
+
+/*
+ * Update the header checksums for a dirty inode based on its contents.
+ * Caller is expected to hold the buffer head underlying oi and mark it
+ * dirty.
+ */
+static void omfs_update_checksums(struct omfs_inode *oi)
+{
+	int xor, i, ofs = 0, count;
+	u16 crc = 0;
+	unsigned char *ptr = (unsigned char *) oi;
+
+	count = be32_to_cpu(oi->i_head.h_body_size);
+	ofs = sizeof(struct omfs_header);
+
+	crc = crc_itu_t(crc, ptr + ofs, count);
+	oi->i_head.h_crc = cpu_to_be16(crc);
+
+	xor = ptr[0];
+	for (i = 1; i < OMFS_XOR_COUNT; i++)
+		xor ^= ptr[i];
+
+	oi->i_head.h_check_xor = xor;
+}
+
+static int __omfs_write_inode(struct inode *inode, int wait)
+{
+	struct omfs_inode *oi;
+	struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
+	struct buffer_head *bh, *bh2;
+	u64 ctime;
+	int i;
+	int ret = -EIO;
+	int sync_failed = 0;
+
+	/* get current inode since we may have written sibling ptrs etc. */
+	bh = omfs_bread(inode->i_sb, inode->i_ino);
+	if (!bh)
+		goto out;
+
+	oi = (struct omfs_inode *) bh->b_data;
+
+	oi->i_head.h_self = cpu_to_be64(inode->i_ino);
+	if (S_ISDIR(inode->i_mode))
+		oi->i_type = OMFS_DIR;
+	else if (S_ISREG(inode->i_mode))
+		oi->i_type = OMFS_FILE;
+	else {
+		printk(KERN_WARNING "omfs: unknown file type: %d\n",
+			inode->i_mode);
+		goto out_brelse;
+	}
+
+	oi->i_head.h_body_size = cpu_to_be32(sbi->s_sys_blocksize -
+		sizeof(struct omfs_header));
+	oi->i_head.h_version = 1;
+	oi->i_head.h_type = OMFS_INODE_NORMAL;
+	oi->i_head.h_magic = OMFS_IMAGIC;
+	oi->i_size = cpu_to_be64(inode->i_size);
+
+	ctime = inode_get_ctime_sec(inode) * 1000LL +
+		((inode_get_ctime_nsec(inode) + 999)/1000);
+	oi->i_ctime = cpu_to_be64(ctime);
+
+	omfs_update_checksums(oi);
+
+	mark_buffer_dirty(bh);
+	if (wait) {
+		sync_dirty_buffer(bh);
+		if (buffer_req(bh) && !buffer_uptodate(bh))
+			sync_failed = 1;
+	}
+
+	/* if mirroring writes, copy to next fsblock */
+	for (i = 1; i < sbi->s_mirrors; i++) {
+		bh2 = omfs_bread(inode->i_sb, inode->i_ino + i);
+		if (!bh2)
+			goto out_brelse;
+
+		memcpy(bh2->b_data, bh->b_data, bh->b_size);
+		mark_buffer_dirty(bh2);
+		if (wait) {
+			sync_dirty_buffer(bh2);
+			if (buffer_req(bh2) && !buffer_uptodate(bh2))
+				sync_failed = 1;
+		}
+		brelse(bh2);
+	}
+	ret = (sync_failed) ? -EIO : 0;
+out_brelse:
+	brelse(bh);
+out:
+	return ret;
+}
+
+static int omfs_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+	return __omfs_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
+}
+
+int omfs_sync_inode(struct inode *inode)
+{
+	return __omfs_write_inode(inode, 1);
+}
+
+/*
+ * called when an entry is deleted, need to clear the bits in the
+ * bitmaps.
+ */
+static void omfs_evict_inode(struct inode *inode)
+{
+	truncate_inode_pages_final(&inode->i_data);
+	clear_inode(inode);
+
+	if (inode->i_nlink)
+		return;
+
+	if (S_ISREG(inode->i_mode)) {
+		inode->i_size = 0;
+		omfs_shrink_inode(inode);
+	}
+
+	omfs_clear_range(inode->i_sb, inode->i_ino, 2);
+}
+
+struct inode *omfs_iget(struct super_block *sb, ino_t ino)
+{
+	struct omfs_sb_info *sbi = OMFS_SB(sb);
+	struct omfs_inode *oi;
+	struct buffer_head *bh;
+	u64 ctime;
+	unsigned long nsecs;
+	struct inode *inode;
+
+	inode = iget_locked(sb, ino);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode_state_read_once(inode) & I_NEW))
+		return inode;
+
+	bh = omfs_bread(inode->i_sb, ino);
+	if (!bh)
+		goto iget_failed;
+
+	oi = (struct omfs_inode *)bh->b_data;
+
+	/* check self */
+	if (ino != be64_to_cpu(oi->i_head.h_self))
+		goto fail_bh;
+
+	inode->i_uid = sbi->s_uid;
+	inode->i_gid = sbi->s_gid;
+
+	ctime = be64_to_cpu(oi->i_ctime);
+	nsecs = do_div(ctime, 1000) * 1000L;
+
+	inode_set_atime(inode, ctime, nsecs);
+	inode_set_mtime(inode, ctime, nsecs);
+	inode_set_ctime(inode, ctime, nsecs);
+
+	inode->i_mapping->a_ops = &omfs_aops;
+
+	switch (oi->i_type) {
+	case OMFS_DIR:
+		inode->i_mode = S_IFDIR | (S_IRWXUGO & ~sbi->s_dmask);
+		inode->i_op = &omfs_dir_inops;
+		inode->i_fop = &omfs_dir_operations;
+		inode->i_size = sbi->s_sys_blocksize;
+		inc_nlink(inode);
+		break;
+	case OMFS_FILE:
+		inode->i_mode = S_IFREG | (S_IRWXUGO & ~sbi->s_fmask);
+		inode->i_fop = &omfs_file_operations;
+		inode->i_size = be64_to_cpu(oi->i_size);
+		break;
+	}
+	brelse(bh);
+	unlock_new_inode(inode);
+	return inode;
+fail_bh:
+	brelse(bh);
+iget_failed:
+	iget_failed(inode);
+	return ERR_PTR(-EIO);
+}
+
+static void omfs_put_super(struct super_block *sb)
+{
+	struct omfs_sb_info *sbi = OMFS_SB(sb);
+	kfree(sbi->s_imap);
+	kfree(sbi);
+	sb->s_fs_info = NULL;
+}
+
+static int omfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *s = dentry->d_sb;
+	struct omfs_sb_info *sbi = OMFS_SB(s);
+	u64 id = huge_encode_dev(s->s_bdev->bd_dev);
+
+	buf->f_type = OMFS_MAGIC;
+	buf->f_bsize = sbi->s_blocksize;
+	buf->f_blocks = sbi->s_num_blocks;
+	buf->f_files = sbi->s_num_blocks;
+	buf->f_namelen = OMFS_NAMELEN;
+	buf->f_fsid = u64_to_fsid(id);
+
+	buf->f_bfree = buf->f_bavail = buf->f_ffree =
+		omfs_count_free(s);
+
+	return 0;
+}
+
+/*
+ * Display the mount options in /proc/mounts.
+ */
+static int omfs_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct omfs_sb_info *sbi = OMFS_SB(root->d_sb);
+	umode_t cur_umask = current_umask();
+
+	if (!uid_eq(sbi->s_uid, current_uid()))
+		seq_printf(m, ",uid=%u",
+			   from_kuid_munged(&init_user_ns, sbi->s_uid));
+	if (!gid_eq(sbi->s_gid, current_gid()))
+		seq_printf(m, ",gid=%u",
+			   from_kgid_munged(&init_user_ns, sbi->s_gid));
+
+	if (sbi->s_dmask == sbi->s_fmask) {
+		if (sbi->s_fmask != cur_umask)
+			seq_printf(m, ",umask=%o", sbi->s_fmask);
+	} else {
+		if (sbi->s_dmask != cur_umask)
+			seq_printf(m, ",dmask=%o", sbi->s_dmask);
+		if (sbi->s_fmask != cur_umask)
+			seq_printf(m, ",fmask=%o", sbi->s_fmask);
+	}
+
+	return 0;
+}
+
+static const struct super_operations omfs_sops = {
+	.write_inode	= omfs_write_inode,
+	.evict_inode	= omfs_evict_inode,
+	.put_super	= omfs_put_super,
+	.statfs		= omfs_statfs,
+	.show_options	= omfs_show_options,
+};
+
+/*
+ * For Rio Karma, there is an on-disk free bitmap whose location is
+ * stored in the root block.  For ReplayTV, there is no such free bitmap
+ * so we have to walk the tree.  Both inodes and file data are allocated
+ * from the same map.  This array can be big (300k) so we allocate
+ * in units of the blocksize.
+ */
+static int omfs_get_imap(struct super_block *sb)
+{
+	unsigned int bitmap_size, array_size;
+	int count;
+	struct omfs_sb_info *sbi = OMFS_SB(sb);
+	struct buffer_head *bh;
+	unsigned long **ptr;
+	sector_t block;
+
+	bitmap_size = DIV_ROUND_UP(sbi->s_num_blocks, 8);
+	array_size = DIV_ROUND_UP(bitmap_size, sb->s_blocksize);
+
+	if (sbi->s_bitmap_ino == ~0ULL)
+		goto out;
+
+	sbi->s_imap_size = array_size;
+	sbi->s_imap = kcalloc(array_size, sizeof(unsigned long *), GFP_KERNEL);
+	if (!sbi->s_imap)
+		goto nomem;
+
+	block = clus_to_blk(sbi, sbi->s_bitmap_ino);
+	if (block >= sbi->s_num_blocks)
+		goto nomem;
+
+	ptr = sbi->s_imap;
+	for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
+		bh = sb_bread(sb, block++);
+		if (!bh)
+			goto nomem_free;
+		*ptr = kmemdup(bh->b_data, sb->s_blocksize, GFP_KERNEL);
+		if (!*ptr) {
+			brelse(bh);
+			goto nomem_free;
+		}
+		if (count < sb->s_blocksize)
+			memset((void *)*ptr + count, 0xff,
+				sb->s_blocksize - count);
+		brelse(bh);
+		ptr++;
+	}
+out:
+	return 0;
+
+nomem_free:
+	for (count = 0; count < array_size; count++)
+		kfree(sbi->s_imap[count]);
+
+	kfree(sbi->s_imap);
+nomem:
+	sbi->s_imap = NULL;
+	sbi->s_imap_size = 0;
+	return -ENOMEM;
+}
+
+struct omfs_mount_options {
+	kuid_t s_uid;
+	kgid_t s_gid;
+	int s_dmask;
+	int s_fmask;
+};
+
+enum {
+	Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask,
+};
+
+static const struct fs_parameter_spec omfs_param_spec[] = {
+	fsparam_uid	("uid",		Opt_uid),
+	fsparam_gid	("gid",		Opt_gid),
+	fsparam_u32oct	("umask",	Opt_umask),
+	fsparam_u32oct	("dmask",	Opt_dmask),
+	fsparam_u32oct	("fmask",	Opt_fmask),
+	{}
+};
+
+static int
+omfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct omfs_mount_options *opts = fc->fs_private;
+	int token;
+	struct fs_parse_result result;
+
+	/* All options are ignored on remount */
+	if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE)
+		return 0;
+
+	token = fs_parse(fc, omfs_param_spec, param, &result);
+	if (token < 0)
+		return token;
+
+	switch (token) {
+	case Opt_uid:
+		opts->s_uid = result.uid;
+		break;
+	case Opt_gid:
+		opts->s_gid = result.gid;
+		break;
+	case Opt_umask:
+		opts->s_fmask = opts->s_dmask = result.uint_32;
+		break;
+	case Opt_dmask:
+		opts->s_dmask = result.uint_32;
+		break;
+	case Opt_fmask:
+		opts->s_fmask = result.uint_32;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void
+omfs_set_options(struct omfs_sb_info *sbi, struct omfs_mount_options *opts)
+{
+	sbi->s_uid = opts->s_uid;
+	sbi->s_gid = opts->s_gid;
+	sbi->s_dmask = opts->s_dmask;
+	sbi->s_fmask = opts->s_fmask;
+}
+
+static int omfs_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+	struct buffer_head *bh, *bh2;
+	struct omfs_super_block *omfs_sb;
+	struct omfs_root_block *omfs_rb;
+	struct omfs_sb_info *sbi;
+	struct inode *root;
+	struct omfs_mount_options *parsed_opts = fc->fs_private;
+	int ret = -EINVAL;
+	int silent = fc->sb_flags & SB_SILENT;
+
+	sbi = kzalloc_obj(struct omfs_sb_info);
+	if (!sbi)
+		return -ENOMEM;
+
+	sb->s_fs_info = sbi;
+
+	omfs_set_options(sbi, parsed_opts);
+
+	sb->s_maxbytes = 0xffffffff;
+
+	sb->s_time_gran = NSEC_PER_MSEC;
+	sb->s_time_min = 0;
+	sb->s_time_max = U64_MAX / MSEC_PER_SEC;
+
+	if (!sb_set_blocksize(sb, 0x200))
+		goto end;
+
+	bh = sb_bread(sb, 0);
+	if (!bh)
+		goto end;
+
+	omfs_sb = (struct omfs_super_block *)bh->b_data;
+
+	if (omfs_sb->s_magic != cpu_to_be32(OMFS_MAGIC)) {
+		if (!silent)
+			printk(KERN_ERR "omfs: Invalid superblock (%x)\n",
+				   omfs_sb->s_magic);
+		goto out_brelse_bh;
+	}
+	sb->s_magic = OMFS_MAGIC;
+
+	sbi->s_num_blocks = be64_to_cpu(omfs_sb->s_num_blocks);
+	sbi->s_blocksize = be32_to_cpu(omfs_sb->s_blocksize);
+	sbi->s_mirrors = be32_to_cpu(omfs_sb->s_mirrors);
+	sbi->s_root_ino = be64_to_cpu(omfs_sb->s_root_block);
+	sbi->s_sys_blocksize = be32_to_cpu(omfs_sb->s_sys_blocksize);
+	mutex_init(&sbi->s_bitmap_lock);
+
+	if (sbi->s_num_blocks > OMFS_MAX_BLOCKS) {
+		printk(KERN_ERR "omfs: sysblock number (%llx) is out of range\n",
+		       (unsigned long long)sbi->s_num_blocks);
+		goto out_brelse_bh;
+	}
+
+	if (sbi->s_sys_blocksize > PAGE_SIZE) {
+		printk(KERN_ERR "omfs: sysblock size (%d) is out of range\n",
+			sbi->s_sys_blocksize);
+		goto out_brelse_bh;
+	}
+
+	if (sbi->s_sys_blocksize < OMFS_DIR_START) {
+		printk(KERN_ERR "omfs: sysblock size (%d) is too small\n",
+			sbi->s_sys_blocksize);
+		goto out_brelse_bh;
+	}
+
+	if (sbi->s_blocksize < sbi->s_sys_blocksize ||
+	    sbi->s_blocksize > OMFS_MAX_BLOCK_SIZE) {
+		printk(KERN_ERR "omfs: block size (%d) is out of range\n",
+			sbi->s_blocksize);
+		goto out_brelse_bh;
+	}
+
+	/*
+	 * Use sys_blocksize as the fs block since it is smaller than a
+	 * page while the fs blocksize can be larger.
+	 */
+	if (!sb_set_blocksize(sb, sbi->s_sys_blocksize))
+		goto out_brelse_bh;
+
+	/*
+	 * ...and the difference goes into a shift.  sys_blocksize is always
+	 * a power of two factor of blocksize.
+	 */
+	sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
+		get_bitmask_order(sbi->s_sys_blocksize);
+
+	bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));
+	if (!bh2)
+		goto out_brelse_bh;
+
+	omfs_rb = (struct omfs_root_block *)bh2->b_data;
+
+	sbi->s_bitmap_ino = be64_to_cpu(omfs_rb->r_bitmap);
+	sbi->s_clustersize = be32_to_cpu(omfs_rb->r_clustersize);
+
+	if (sbi->s_num_blocks != be64_to_cpu(omfs_rb->r_num_blocks)) {
+		printk(KERN_ERR "omfs: block count discrepancy between "
+			"super and root blocks (%llx, %llx)\n",
+			(unsigned long long)sbi->s_num_blocks,
+			(unsigned long long)be64_to_cpu(omfs_rb->r_num_blocks));
+		goto out_brelse_bh2;
+	}
+
+	if (sbi->s_bitmap_ino != ~0ULL &&
+	    sbi->s_bitmap_ino > sbi->s_num_blocks) {
+		printk(KERN_ERR "omfs: free space bitmap location is corrupt "
+			"(%llx, total blocks %llx)\n",
+			(unsigned long long) sbi->s_bitmap_ino,
+			(unsigned long long) sbi->s_num_blocks);
+		goto out_brelse_bh2;
+	}
+	if (sbi->s_clustersize < 1 ||
+	    sbi->s_clustersize > OMFS_MAX_CLUSTER_SIZE) {
+		printk(KERN_ERR "omfs: cluster size out of range (%d)",
+			sbi->s_clustersize);
+		goto out_brelse_bh2;
+	}
+
+	ret = omfs_get_imap(sb);
+	if (ret)
+		goto out_brelse_bh2;
+
+	sb->s_op = &omfs_sops;
+
+	root = omfs_iget(sb, be64_to_cpu(omfs_rb->r_root_dir));
+	if (IS_ERR(root)) {
+		ret = PTR_ERR(root);
+		goto out_brelse_bh2;
+	}
+
+	sb->s_root = d_make_root(root);
+	if (!sb->s_root) {
+		ret = -ENOMEM;
+		goto out_brelse_bh2;
+	}
+	printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
+
+	ret = 0;
+out_brelse_bh2:
+	brelse(bh2);
+out_brelse_bh:
+	brelse(bh);
+end:
+	if (ret)
+		kfree(sbi);
+	return ret;
+}
+
+static int omfs_get_tree(struct fs_context *fc)
+{
+	return get_tree_bdev(fc, omfs_fill_super);
+}
+
+static void omfs_free_fc(struct fs_context *fc);
+
+static const struct fs_context_operations omfs_context_ops = {
+	.parse_param	= omfs_parse_param,
+	.get_tree	= omfs_get_tree,
+	.free		= omfs_free_fc,
+};
+
+static int omfs_init_fs_context(struct fs_context *fc)
+{
+	struct omfs_mount_options *opts;
+
+	opts = kzalloc_obj(*opts);
+	if (!opts)
+		return -ENOMEM;
+
+	/* Set mount options defaults */
+	opts->s_uid = current_uid();
+	opts->s_gid = current_gid();
+	opts->s_dmask = opts->s_fmask = current_umask();
+
+	fc->fs_private = opts;
+	fc->ops = &omfs_context_ops;
+
+	return 0;
+}
+
+static void omfs_free_fc(struct fs_context *fc)
+{
+	kfree(fc->fs_private);
+}
+
+static struct file_system_type omfs_fs_type = {
+	.owner		 = THIS_MODULE,
+	.name		 = "omfs",
+	.kill_sb	 = kill_block_super,
+	.fs_flags	 = FS_REQUIRES_DEV,
+	.init_fs_context = omfs_init_fs_context,
+	.parameters	 = omfs_param_spec,
+};
+MODULE_ALIAS_FS("omfs");
+
+static int __init init_omfs_fs(void)
+{
+	return register_filesystem(&omfs_fs_type);
+}
+
+static void __exit exit_omfs_fs(void)
+{
+	unregister_filesystem(&omfs_fs_type);
+}
+
+module_init(init_omfs_fs);
+module_exit(exit_omfs_fs);
diff --git a/fs/omfs/omfs.h b/fs/omfs/omfs.h
new file mode 100644
index 000000000..4008be73d
--- /dev/null
+++ b/fs/omfs/omfs.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _OMFS_H
+#define _OMFS_H
+
+#include <linux/module.h>
+#include <linux/fs.h>
+
+#include "omfs_fs.h"
+
+/* In-memory structures */
+struct omfs_sb_info {
+	u64 s_num_blocks;
+	u64 s_bitmap_ino;
+	u64 s_root_ino;
+	u32 s_blocksize;
+	u32 s_mirrors;
+	u32 s_sys_blocksize;
+	u32 s_clustersize;
+	int s_block_shift;
+	unsigned long **s_imap;
+	int s_imap_size;
+	struct mutex s_bitmap_lock;
+	kuid_t s_uid;
+	kgid_t s_gid;
+	int s_dmask;
+	int s_fmask;
+};
+
+/* convert a cluster number to a scaled block number */
+static inline sector_t clus_to_blk(struct omfs_sb_info *sbi, sector_t block)
+{
+	return block << sbi->s_block_shift;
+}
+
+static inline struct omfs_sb_info *OMFS_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+/* bitmap.c */
+extern unsigned long omfs_count_free(struct super_block *sb);
+extern int omfs_allocate_block(struct super_block *sb, u64 block);
+extern int omfs_allocate_range(struct super_block *sb, int min_request,
+			int max_request, u64 *return_block, int *return_size);
+extern int omfs_clear_range(struct super_block *sb, u64 block, int count);
+
+/* dir.c */
+extern const struct file_operations omfs_dir_operations;
+extern const struct inode_operations omfs_dir_inops;
+extern int omfs_make_empty(struct inode *inode, struct super_block *sb);
+extern int omfs_is_bad(struct omfs_sb_info *sbi, struct omfs_header *header,
+			u64 fsblock);
+
+/* file.c */
+extern const struct file_operations omfs_file_operations;
+extern const struct inode_operations omfs_file_inops;
+extern const struct address_space_operations omfs_aops;
+extern void omfs_make_empty_table(struct buffer_head *bh, int offset);
+extern int omfs_shrink_inode(struct inode *inode);
+
+/* inode.c */
+extern struct buffer_head *omfs_bread(struct super_block *sb, sector_t block);
+extern struct inode *omfs_iget(struct super_block *sb, ino_t inode);
+extern struct inode *omfs_new_inode(struct inode *dir, umode_t mode);
+extern int omfs_reserve_block(struct super_block *sb, sector_t block);
+extern int omfs_find_empty_block(struct super_block *sb, int mode, ino_t *ino);
+extern int omfs_sync_inode(struct inode *inode);
+
+#endif
diff --git a/fs/omfs/omfs_fs.h b/fs/omfs/omfs_fs.h
new file mode 100644
index 000000000..1ff6b9e41
--- /dev/null
+++ b/fs/omfs/omfs_fs.h
@@ -0,0 +1,83 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _OMFS_FS_H
+#define _OMFS_FS_H
+
+/* OMFS On-disk structures */
+
+#define OMFS_MAGIC 0xC2993D87
+#define OMFS_IMAGIC 0xD2
+
+#define OMFS_DIR 'D'
+#define OMFS_FILE 'F'
+#define OMFS_INODE_NORMAL 'e'
+#define OMFS_INODE_CONTINUATION 'c'
+#define OMFS_INODE_SYSTEM 's'
+#define OMFS_NAMELEN 256
+#define OMFS_DIR_START 0x1b8
+#define OMFS_EXTENT_START 0x1d0
+#define OMFS_EXTENT_CONT 0x40
+#define OMFS_XOR_COUNT 19
+#define OMFS_MAX_BLOCK_SIZE 8192
+#define OMFS_MAX_CLUSTER_SIZE 8
+#define OMFS_MAX_BLOCKS (1ul << 31)
+
+struct omfs_super_block {
+	char s_fill1[256];
+	__be64 s_root_block;		/* block number of omfs_root_block */
+	__be64 s_num_blocks;		/* total number of FS blocks */
+	__be32 s_magic;			/* OMFS_MAGIC */
+	__be32 s_blocksize;		/* size of a block */
+	__be32 s_mirrors;		/* # of mirrors of system blocks */
+	__be32 s_sys_blocksize;		/* size of non-data blocks */
+};
+
+struct omfs_header {
+	__be64 h_self;			/* FS block where this is located */
+	__be32 h_body_size;		/* size of useful data after header */
+	__be16 h_crc;			/* crc-ccitt of body_size bytes */
+	char h_fill1[2];
+	u8 h_version;			/* version, always 1 */
+	char h_type;			/* OMFS_INODE_X */
+	u8 h_magic;			/* OMFS_IMAGIC */
+	u8 h_check_xor;			/* XOR of header bytes before this */
+	__be32 h_fill2;
+};
+
+struct omfs_root_block {
+	struct omfs_header r_head;	/* header */
+	__be64 r_fill1;
+	__be64 r_num_blocks;		/* total number of FS blocks */
+	__be64 r_root_dir;		/* block # of root directory */
+	__be64 r_bitmap;		/* block # of free space bitmap */
+	__be32 r_blocksize;		/* size of a block */
+	__be32 r_clustersize;		/* size allocated for data blocks */
+	__be64 r_mirrors;		/* # of mirrors of system blocks */
+	char r_name[OMFS_NAMELEN];	/* partition label */
+};
+
+struct omfs_inode {
+	struct omfs_header i_head;	/* header */
+	__be64 i_parent;		/* parent containing this inode */
+	__be64 i_sibling;		/* next inode in hash bucket */
+	__be64 i_ctime;			/* ctime, in milliseconds */
+	char i_fill1[35];
+	char i_type;			/* OMFS_[DIR,FILE] */
+	__be32 i_fill2;
+	char i_fill3[64];
+	char i_name[OMFS_NAMELEN];	/* filename */
+	__be64 i_size;			/* size of file, in bytes */
+};
+
+struct omfs_extent_entry {
+	__be64 e_cluster;		/* start location of a set of blocks */
+	__be64 e_blocks;		/* number of blocks after e_cluster */
+};
+
+struct omfs_extent {
+	__be64 e_next;			/* next extent table location */
+	__be32 e_extent_count;		/* total # extents in this table */
+	__be32 e_fill;
+	struct omfs_extent_entry e_entry[];	/* start of extent entries */
+};
+
+#endif