diff --git a/MAINTAINERS b/MAINTAINERS
index a049abccaa26..8eb6f02a1efa 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18284,6 +18284,15 @@ L:	linux-kernel@vger.kernel.org
 S:	Maintained
 F:	arch/x86/kernel/cpu/zhaoxin.c
 
+ZONEFS FILESYSTEM
+M:	Damien Le Moal <damien.lemoal@wdc.com>
+M:	Naohiro Aota <naohiro.aota@wdc.com>
+R:	Johannes Thumshirn <jth@kernel.org>
+L:	linux-fsdevel@vger.kernel.org
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs.git
+S:	Maintained
+F:	fs/zonefs/
+
 ZPOOL COMPRESSED PAGE STORAGE API
 M:	Dan Streetman <ddstreet@ieee.org>
 L:	linux-mm@kvack.org
diff --git a/fs/Kconfig b/fs/Kconfig
index 7b623e9fc1b0..a3f97ca2bd46 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -40,6 +40,7 @@ source "fs/ocfs2/Kconfig"
 source "fs/btrfs/Kconfig"
 source "fs/nilfs2/Kconfig"
 source "fs/f2fs/Kconfig"
+source "fs/zonefs/Kconfig"
 
 config FS_DAX
 	bool "Direct Access (DAX) support"
diff --git a/fs/Makefile b/fs/Makefile
index 1148c555c4d3..527f228a5e8a 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -133,3 +133,4 @@ obj-$(CONFIG_CEPH_FS)		+= ceph/
 obj-$(CONFIG_PSTORE)		+= pstore/
 obj-$(CONFIG_EFIVAR_FS)		+= efivarfs/
 obj-$(CONFIG_EROFS_FS)		+= erofs/
+obj-$(CONFIG_ZONEFS_FS)		+= zonefs/
diff --git a/fs/zonefs/Kconfig b/fs/zonefs/Kconfig
new file mode 100644
index 000000000000..03a4ef80f975
--- /dev/null
+++ b/fs/zonefs/Kconfig
@@ -0,0 +1,9 @@
+config ZONEFS_FS
+	tristate "zonefs filesystem support"
+	depends on BLOCK
+	depends on BLK_DEV_ZONED
+	help
+	  zonefs is a simple File System which exposes zones of a zoned block
+	  device (e.g. host-managed or host-aware SMR disk drives) as files.
+
+	  If unsure, say N.
diff --git a/fs/zonefs/Makefile b/fs/zonefs/Makefile
new file mode 100644
index 000000000000..75a380aa1ae1
--- /dev/null
+++ b/fs/zonefs/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_ZONEFS_FS) += zonefs.o
+
+zonefs-y	:= super.o
diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
new file mode 100644
index 000000000000..9a612d75d324
--- /dev/null
+++ b/fs/zonefs/super.c
@@ -0,0 +1,1175 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Simple zone file system for zoned block devices.
+ *
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ */
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/magic.h>
+#include <linux/iomap.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include <linux/statfs.h>
+#include <linux/writeback.h>
+#include <linux/quotaops.h>
+#include <linux/seq_file.h>
+#include <linux/parser.h>
+#include <linux/uio.h>
+#include <linux/mman.h>
+#include <linux/sched/mm.h>
+#include <linux/crc32.h>
+
+#include "zonefs.h"
+
+static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
+			      unsigned int flags, struct iomap *iomap,
+			      struct iomap *srcmap)
+{
+	struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	loff_t max_isize = zi->i_max_size;
+	loff_t isize;
+
+	/*
+	 * For sequential zones, enforce direct IO writes. This is already
+	 * checked when writes are issued, so warn about this here if we
+	 * get buffered write to a sequential file inode.
+	 */
+	if (WARN_ON_ONCE(zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
+			 (flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT)))
+		return -EIO;
+
+	/*
+	 * For all zones, all blocks are always mapped. For sequential zones,
+	 * all blocks after the write pointer (inode size) are always unwritten.
+	 */
+	mutex_lock(&zi->i_truncate_mutex);
+	isize = i_size_read(inode);
+	if (offset >= isize) {
+		length = min(length, max_isize - offset);
+		if (zi->i_ztype == ZONEFS_ZTYPE_CNV)
+			iomap->type = IOMAP_MAPPED;
+		else
+			iomap->type = IOMAP_UNWRITTEN;
+	} else {
+		length = min(length, isize - offset);
+		iomap->type = IOMAP_MAPPED;
+	}
+	mutex_unlock(&zi->i_truncate_mutex);
+
+	iomap->offset = offset & (~sbi->s_blocksize_mask);
+	iomap->length = ((offset + length + sbi->s_blocksize_mask) &
+			 (~sbi->s_blocksize_mask)) - iomap->offset;
+	iomap->bdev = inode->i_sb->s_bdev;
+	iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
+
+	return 0;
+}
+
+static const struct iomap_ops zonefs_iomap_ops = {
+	.iomap_begin	= zonefs_iomap_begin,
+};
+
+static int zonefs_readpage(struct file *unused, struct page *page)
+{
+	return iomap_readpage(page, &zonefs_iomap_ops);
+}
+
+static int zonefs_readpages(struct file *unused, struct address_space *mapping,
+			    struct list_head *pages, unsigned int nr_pages)
+{
+	return iomap_readpages(mapping, pages, nr_pages, &zonefs_iomap_ops);
+}
+
+static int zonefs_map_blocks(struct iomap_writepage_ctx *wpc,
+			     struct inode *inode, loff_t offset)
+{
+	if (offset >= wpc->iomap.offset &&
+	    offset < wpc->iomap.offset + wpc->iomap.length)
+		return 0;
+
+	memset(&wpc->iomap, 0, sizeof(wpc->iomap));
+	return zonefs_iomap_begin(inode, offset, ZONEFS_I(inode)->i_max_size,
+				  0, &wpc->iomap, NULL);
+}
+
+static const struct iomap_writeback_ops zonefs_writeback_ops = {
+	.map_blocks		= zonefs_map_blocks,
+};
+
+static int zonefs_writepage(struct page *page, struct writeback_control *wbc)
+{
+	struct iomap_writepage_ctx wpc = { };
+
+	return iomap_writepage(page, wbc, &wpc, &zonefs_writeback_ops);
+}
+
+static int zonefs_writepages(struct address_space *mapping,
+			     struct writeback_control *wbc)
+{
+	struct iomap_writepage_ctx wpc = { };
+
+	return iomap_writepages(mapping, wbc, &wpc, &zonefs_writeback_ops);
+}
+
+static const struct address_space_operations zonefs_file_aops = {
+	.readpage		= zonefs_readpage,
+	.readpages		= zonefs_readpages,
+	.writepage		= zonefs_writepage,
+	.writepages		= zonefs_writepages,
+	.set_page_dirty		= iomap_set_page_dirty,
+	.releasepage		= iomap_releasepage,
+	.invalidatepage		= iomap_invalidatepage,
+	.migratepage		= iomap_migrate_page,
+	.is_partially_uptodate  = iomap_is_partially_uptodate,
+	.error_remove_page	= generic_error_remove_page,
+	.direct_IO		= noop_direct_IO,
+};
+
+static void zonefs_update_stats(struct inode *inode, loff_t new_isize)
+{
+	struct super_block *sb = inode->i_sb;
+	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+	loff_t old_isize = i_size_read(inode);
+
+	if (new_isize == old_isize)
+		return;
+
+	spin_lock(&sbi->s_lock);
+
+	if (!new_isize) {
+		/* File truncated to 0 */
+		sbi->s_used_blocks -= old_isize >> sb->s_blocksize_bits;
+	} else if (new_isize > old_isize) {
+		/* File written or truncated to max size */
+		sbi->s_used_blocks +=
+			(new_isize - old_isize) >> sb->s_blocksize_bits;
+	} else {
+		/* Sequential zone files can only grow or be truncated to 0 */
+		WARN_ON(new_isize < old_isize);
+	}
+
+	spin_unlock(&sbi->s_lock);
+}
+
+static int zonefs_seq_file_truncate(struct inode *inode, loff_t isize)
+{
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	loff_t old_isize;
+	enum req_opf op;
+	int ret = 0;
+
+	/*
+	 * For sequential zone files, we can only allow truncating to 0 size,
+	 * which is equivalent to a zone reset, or to the maximum file size,
+	 * which is equivalent to a zone finish.
+	 */
+	if (!isize)
+		op = REQ_OP_ZONE_RESET;
+	else if (isize == zi->i_max_size)
+		op = REQ_OP_ZONE_FINISH;
+	else
+		return -EPERM;
+
+	inode_dio_wait(inode);
+
+	/* Serialize against page faults */
+	down_write(&zi->i_mmap_sem);
+
+	/* Serialize against zonefs_iomap_begin() */
+	mutex_lock(&zi->i_truncate_mutex);
+
+	old_isize = i_size_read(inode);
+	if (isize == old_isize)
+		goto unlock;
+
+	ret = blkdev_zone_mgmt(inode->i_sb->s_bdev, op, zi->i_zsector,
+			       zi->i_max_size >> SECTOR_SHIFT, GFP_NOFS);
+	if (ret) {
+		zonefs_err(inode->i_sb,
+			   "Zone management operation at %llu failed %d",
+			   zi->i_zsector, ret);
+		goto unlock;
+	}
+
+	zonefs_update_stats(inode, isize);
+	truncate_setsize(inode, isize);
+	zi->i_wpoffset = isize;
+
+unlock:
+	mutex_unlock(&zi->i_truncate_mutex);
+	up_write(&zi->i_mmap_sem);
+
+	return ret;
+}
+
+static int zonefs_inode_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+	struct inode *inode = d_inode(dentry);
+	int ret;
+
+	ret = setattr_prepare(dentry, iattr);
+	if (ret)
+		return ret;
+
+	/* Files and sub-directories cannot be created or deleted */
+	if ((iattr->ia_valid & ATTR_MODE) && (inode->i_mode & S_IFDIR) &&
+	    (iattr->ia_mode & 0222))
+		return -EPERM;
+
+	if (((iattr->ia_valid & ATTR_UID) &&
+	     !uid_eq(iattr->ia_uid, inode->i_uid)) ||
+	    ((iattr->ia_valid & ATTR_GID) &&
+	     !gid_eq(iattr->ia_gid, inode->i_gid))) {
+		ret = dquot_transfer(inode, iattr);
+		if (ret)
+			return ret;
+	}
+
+	if (iattr->ia_valid & ATTR_SIZE) {
+		/* The size of conventional zone files cannot be changed */
+		if (ZONEFS_I(inode)->i_ztype == ZONEFS_ZTYPE_CNV)
+			return -EPERM;
+
+		ret = zonefs_seq_file_truncate(inode, iattr->ia_size);
+		if (ret)
+			return ret;
+	}
+
+	setattr_copy(inode, iattr);
+
+	return 0;
+}
+
+static const struct inode_operations zonefs_file_inode_operations = {
+	.setattr	= zonefs_inode_setattr,
+};
+
+static int zonefs_file_fsync(struct file *file, loff_t start, loff_t end,
+			     int datasync)
+{
+	struct inode *inode = file_inode(file);
+	int ret = 0;
+
+	/*
+	 * Since only direct writes are allowed in sequential files, page cache
+	 * flush is needed only for conventional zone files.
+	 */
+	if (ZONEFS_I(inode)->i_ztype == ZONEFS_ZTYPE_CNV) {
+		ret = file_write_and_wait_range(file, start, end);
+		if (ret)
+			return ret;
+		ret = file_check_and_advance_wb_err(file);
+	}
+
+	if (ret == 0)
+		ret = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
+
+	return ret;
+}
+
+static vm_fault_t zonefs_filemap_fault(struct vm_fault *vmf)
+{
+	struct zonefs_inode_info *zi = ZONEFS_I(file_inode(vmf->vma->vm_file));
+	vm_fault_t ret;
+
+	down_read(&zi->i_mmap_sem);
+	ret = filemap_fault(vmf);
+	up_read(&zi->i_mmap_sem);
+
+	return ret;
+}
+
+static vm_fault_t zonefs_filemap_page_mkwrite(struct vm_fault *vmf)
+{
+	struct inode *inode = file_inode(vmf->vma->vm_file);
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	vm_fault_t ret;
+
+	sb_start_pagefault(inode->i_sb);
+	file_update_time(vmf->vma->vm_file);
+
+	/* Serialize against truncates */
+	down_read(&zi->i_mmap_sem);
+	ret = iomap_page_mkwrite(vmf, &zonefs_iomap_ops);
+	up_read(&zi->i_mmap_sem);
+
+	sb_end_pagefault(inode->i_sb);
+	return ret;
+}
+
+static const struct vm_operations_struct zonefs_file_vm_ops = {
+	.fault		= zonefs_filemap_fault,
+	.map_pages	= filemap_map_pages,
+	.page_mkwrite	= zonefs_filemap_page_mkwrite,
+};
+
+static int zonefs_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	/*
+	 * Conventional zone files can be mmap-ed READ/WRITE.
+	 * For sequential zone files, only readonly mappings are possible.
+	 */
+	if (ZONEFS_I(file_inode(file))->i_ztype == ZONEFS_ZTYPE_SEQ &&
+	    (vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
+		return -EINVAL;
+
+	file_accessed(file);
+	vma->vm_ops = &zonefs_file_vm_ops;
+
+	return 0;
+}
+
+static loff_t zonefs_file_llseek(struct file *file, loff_t offset, int whence)
+{
+	loff_t isize = i_size_read(file_inode(file));
+
+	/*
+	 * Seeks are limited to below the zone size for conventional zones
+	 * and below the zone write pointer for sequential zones. In both
+	 * cases, this limit is the inode size.
+	 */
+	return generic_file_llseek_size(file, offset, whence, isize, isize);
+}
+
+static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	loff_t max_pos;
+	size_t count;
+	ssize_t ret;
+
+	if (iocb->ki_pos >= zi->i_max_size)
+		return 0;
+
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (!inode_trylock_shared(inode))
+			return -EAGAIN;
+	} else {
+		inode_lock_shared(inode);
+	}
+
+	mutex_lock(&zi->i_truncate_mutex);
+
+	/*
+	 * Limit read operations to written data.
+	 */
+	max_pos = i_size_read(inode);
+	if (iocb->ki_pos >= max_pos) {
+		mutex_unlock(&zi->i_truncate_mutex);
+		ret = 0;
+		goto out;
+	}
+
+	iov_iter_truncate(to, max_pos - iocb->ki_pos);
+
+	mutex_unlock(&zi->i_truncate_mutex);
+
+	count = iov_iter_count(to);
+
+	if (iocb->ki_flags & IOCB_DIRECT) {
+		if ((iocb->ki_pos | count) & sbi->s_blocksize_mask) {
+			ret = -EINVAL;
+			goto out;
+		}
+		file_accessed(iocb->ki_filp);
+		ret = iomap_dio_rw(iocb, to, &zonefs_iomap_ops, NULL,
+				   is_sync_kiocb(iocb));
+	} else {
+		ret = generic_file_read_iter(iocb, to);
+	}
+
+out:
+	inode_unlock_shared(inode);
+
+	return ret;
+}
+
+static int zonefs_report_zones_err_cb(struct blk_zone *zone, unsigned int idx,
+				      void *data)
+{
+	struct inode *inode = data;
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	loff_t pos;
+
+	/*
+	 * The condition of the zone may have change. Check it and adjust the
+	 * inode information as needed, similarly to zonefs_init_file_inode().
+	 */
+	if (zone->cond == BLK_ZONE_COND_OFFLINE) {
+		inode->i_flags |= S_IMMUTABLE;
+		inode->i_mode &= ~0777;
+		zone->wp = zone->start;
+	} else if (zone->cond == BLK_ZONE_COND_READONLY) {
+		inode->i_flags |= S_IMMUTABLE;
+		inode->i_mode &= ~0222;
+	}
+
+	pos = (zone->wp - zone->start) << SECTOR_SHIFT;
+	zi->i_wpoffset = pos;
+	if (i_size_read(inode) != pos) {
+		zonefs_update_stats(inode, pos);
+		i_size_write(inode, pos);
+	}
+
+	return 0;
+}
+
+/*
+ * When a write error occurs in a sequential zone, the zone write pointer
+ * position must be refreshed to correct the file size and zonefs inode
+ * write pointer offset.
+ */
+static int zonefs_seq_file_write_failed(struct inode *inode, int error)
+{
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	struct super_block *sb = inode->i_sb;
+	sector_t sector = zi->i_zsector;
+	unsigned int nofs_flag;
+	int ret;
+
+	zonefs_warn(sb, "Updating inode zone %llu info\n", sector);
+
+	/*
+	 * blkdev_report_zones() uses GFP_KERNEL by default. Force execution as
+	 * if GFP_NOFS was specified so that it will not end up recursing into
+	 * the FS on memory allocation.
+	 */
+	nofs_flag = memalloc_nofs_save();
+	ret = blkdev_report_zones(sb->s_bdev, sector, 1,
+				  zonefs_report_zones_err_cb, inode);
+	memalloc_nofs_restore(nofs_flag);
+
+	if (ret != 1) {
+		if (!ret)
+			ret = -EIO;
+		zonefs_err(sb, "Get zone %llu report failed %d\n",
+			   sector, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int zonefs_file_dio_write_end(struct kiocb *iocb, ssize_t size, int ret,
+				     unsigned int flags)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+
+	if (ret)
+		return ret;
+
+	/*
+	 * Conventional zone file size is fixed to the zone size so there
+	 * is no need to do anything.
+	 */
+	if (zi->i_ztype == ZONEFS_ZTYPE_CNV)
+		return 0;
+
+	mutex_lock(&zi->i_truncate_mutex);
+
+	if (size < 0) {
+		ret = zonefs_seq_file_write_failed(inode, size);
+	} else if (i_size_read(inode) < iocb->ki_pos + size) {
+		zonefs_update_stats(inode, iocb->ki_pos + size);
+		i_size_write(inode, iocb->ki_pos + size);
+	}
+
+	mutex_unlock(&zi->i_truncate_mutex);
+
+	return ret;
+}
+
+static const struct iomap_dio_ops zonefs_dio_ops = {
+	.end_io			= zonefs_file_dio_write_end,
+};
+
+static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	size_t count;
+	ssize_t ret;
+
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (!inode_trylock(inode))
+			return -EAGAIN;
+	} else {
+		inode_lock(inode);
+	}
+
+	ret = generic_write_checks(iocb, from);
+	if (ret <= 0)
+		goto out;
+
+	iov_iter_truncate(from, zi->i_max_size - iocb->ki_pos);
+	count = iov_iter_count(from);
+
+	/*
+	 * Direct writes must be aligned to the block size, that is, the device
+	 * physical sector size, to avoid errors when writing sequential zones
+	 * on 512e devices (512B logical sector, 4KB physical sectors).
+	 */
+	if ((iocb->ki_pos | count) & sbi->s_blocksize_mask) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Enforce sequential writes (append only) in sequential zones.
+	 */
+	mutex_lock(&zi->i_truncate_mutex);
+	if (zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
+	    iocb->ki_pos != zi->i_wpoffset) {
+		zonefs_err(inode->i_sb,
+			   "Unaligned write at %llu + %zu (wp %llu)\n",
+			   iocb->ki_pos, count,
+			   zi->i_wpoffset);
+		mutex_unlock(&zi->i_truncate_mutex);
+		ret = -EINVAL;
+		goto out;
+	}
+	mutex_unlock(&zi->i_truncate_mutex);
+
+	ret = iomap_dio_rw(iocb, from, &zonefs_iomap_ops, &zonefs_dio_ops,
+			   is_sync_kiocb(iocb));
+	if (zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
+	    (ret > 0 || ret == -EIOCBQUEUED)) {
+		if (ret > 0)
+			count = ret;
+		mutex_lock(&zi->i_truncate_mutex);
+		zi->i_wpoffset += count;
+		mutex_unlock(&zi->i_truncate_mutex);
+	}
+
+out:
+	inode_unlock(inode);
+
+	return ret;
+}
+
+static ssize_t zonefs_file_buffered_write(struct kiocb *iocb,
+					  struct iov_iter *from)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	size_t count;
+	ssize_t ret;
+
+	/*
+	 * Direct IO writes are mandatory for sequential zones so that the
+	 * write IO order is preserved.
+	 */
+	if (zi->i_ztype == ZONEFS_ZTYPE_SEQ)
+		return -EIO;
+
+	if (iocb->ki_flags & IOCB_NOWAIT) {
+		if (!inode_trylock(inode))
+			return -EAGAIN;
+	} else {
+		inode_lock(inode);
+	}
+
+	ret = generic_write_checks(iocb, from);
+	if (ret <= 0)
+		goto out;
+
+	iov_iter_truncate(from, zi->i_max_size - iocb->ki_pos);
+	count = iov_iter_count(from);
+
+	ret = iomap_file_buffered_write(iocb, from, &zonefs_iomap_ops);
+	if (ret > 0)
+		iocb->ki_pos += ret;
+
+out:
+	inode_unlock(inode);
+	if (ret > 0)
+		ret = generic_write_sync(iocb, ret);
+
+	return ret;
+}
+
+static ssize_t zonefs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+
+	/*
+	 * Check that the write operation does not go beyond the zone size.
+	 */
+	if (iocb->ki_pos >= ZONEFS_I(inode)->i_max_size)
+		return -EFBIG;
+
+	if (iocb->ki_flags & IOCB_DIRECT)
+		return zonefs_file_dio_write(iocb, from);
+
+	return zonefs_file_buffered_write(iocb, from);
+}
+
+static const struct file_operations zonefs_file_operations = {
+	.open		= generic_file_open,
+	.fsync		= zonefs_file_fsync,
+	.mmap		= zonefs_file_mmap,
+	.llseek		= zonefs_file_llseek,
+	.read_iter	= zonefs_file_read_iter,
+	.write_iter	= zonefs_file_write_iter,
+	.splice_read	= generic_file_splice_read,
+	.splice_write	= iter_file_splice_write,
+	.iopoll		= iomap_dio_iopoll,
+};
+
+static struct kmem_cache *zonefs_inode_cachep;
+
+static struct inode *zonefs_alloc_inode(struct super_block *sb)
+{
+	struct zonefs_inode_info *zi;
+
+	zi = kmem_cache_alloc(zonefs_inode_cachep, GFP_KERNEL);
+	if (!zi)
+		return NULL;
+
+	inode_init_once(&zi->i_vnode);
+	mutex_init(&zi->i_truncate_mutex);
+	init_rwsem(&zi->i_mmap_sem);
+
+	return &zi->i_vnode;
+}
+
+static void zonefs_free_inode(struct inode *inode)
+{
+	kmem_cache_free(zonefs_inode_cachep, ZONEFS_I(inode));
+}
+
+/*
+ * File system stat.
+ */
+static int zonefs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+	enum zonefs_ztype t;
+	u64 fsid;
+
+	buf->f_type = ZONEFS_MAGIC;
+	buf->f_bsize = sb->s_blocksize;
+	buf->f_namelen = ZONEFS_NAME_MAX;
+
+	spin_lock(&sbi->s_lock);
+
+	buf->f_blocks = sbi->s_blocks;
+	if (WARN_ON(sbi->s_used_blocks > sbi->s_blocks))
+		buf->f_bfree = 0;
+	else
+		buf->f_bfree = buf->f_blocks - sbi->s_used_blocks;
+	buf->f_bavail = buf->f_bfree;
+
+	for (t = 0; t < ZONEFS_ZTYPE_MAX; t++) {
+		if (sbi->s_nr_files[t])
+			buf->f_files += sbi->s_nr_files[t] + 1;
+	}
+	buf->f_ffree = 0;
+
+	spin_unlock(&sbi->s_lock);
+
+	fsid = le64_to_cpup((void *)sbi->s_uuid.b) ^
+		le64_to_cpup((void *)sbi->s_uuid.b + sizeof(u64));
+	buf->f_fsid.val[0] = (u32)fsid;
+	buf->f_fsid.val[1] = (u32)(fsid >> 32);
+
+	return 0;
+}
+
+static const struct super_operations zonefs_sops = {
+	.alloc_inode	= zonefs_alloc_inode,
+	.free_inode	= zonefs_free_inode,
+	.statfs		= zonefs_statfs,
+};
+
+static const struct inode_operations zonefs_dir_inode_operations = {
+	.lookup		= simple_lookup,
+	.setattr	= zonefs_inode_setattr,
+};
+
+static void zonefs_init_dir_inode(struct inode *parent, struct inode *inode)
+{
+	inode_init_owner(inode, parent, S_IFDIR | 0555);
+	inode->i_op = &zonefs_dir_inode_operations;
+	inode->i_fop = &simple_dir_operations;
+	set_nlink(inode, 2);
+	inc_nlink(parent);
+}
+
+static void zonefs_init_file_inode(struct inode *inode, struct blk_zone *zone)
+{
+	struct super_block *sb = inode->i_sb;
+	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	umode_t	perm = sbi->s_perm;
+
+	if (zone->cond == BLK_ZONE_COND_OFFLINE) {
+		/*
+		 * Dead zone: make the inode immutable, disable all accesses
+		 * and set the file size to 0.
+		 */
+		inode->i_flags |= S_IMMUTABLE;
+		zone->wp = zone->start;
+		perm &= ~0777;
+	} else if (zone->cond == BLK_ZONE_COND_READONLY) {
+		/* Do not allow writes in read-only zones */
+		inode->i_flags |= S_IMMUTABLE;
+		perm &= ~0222;
+	}
+
+	zi->i_ztype = zonefs_zone_type(zone);
+	zi->i_zsector = zone->start;
+	zi->i_max_size = min_t(loff_t, MAX_LFS_FILESIZE,
+			       zone->len << SECTOR_SHIFT);
+	if (zi->i_ztype == ZONEFS_ZTYPE_CNV)
+		zi->i_wpoffset = zi->i_max_size;
+	else
+		zi->i_wpoffset = (zone->wp - zone->start) << SECTOR_SHIFT;
+
+	inode->i_mode = S_IFREG | perm;
+	inode->i_uid = sbi->s_uid;
+	inode->i_gid = sbi->s_gid;
+	inode->i_size = zi->i_wpoffset;
+	inode->i_blocks = zone->len;
+
+	inode->i_op = &zonefs_file_inode_operations;
+	inode->i_fop = &zonefs_file_operations;
+	inode->i_mapping->a_ops = &zonefs_file_aops;
+
+	sb->s_maxbytes = max(zi->i_max_size, sb->s_maxbytes);
+	sbi->s_blocks += zi->i_max_size >> sb->s_blocksize_bits;
+	sbi->s_used_blocks += zi->i_wpoffset >> sb->s_blocksize_bits;
+}
+
+static struct dentry *zonefs_create_inode(struct dentry *parent,
+					const char *name, struct blk_zone *zone)
+{
+	struct inode *dir = d_inode(parent);
+	struct dentry *dentry;
+	struct inode *inode;
+
+	dentry = d_alloc_name(parent, name);
+	if (!dentry)
+		return NULL;
+
+	inode = new_inode(parent->d_sb);
+	if (!inode)
+		goto out;
+
+	inode->i_ino = get_next_ino();
+	inode->i_ctime = inode->i_mtime = inode->i_atime = dir->i_ctime;
+	if (zone)
+		zonefs_init_file_inode(inode, zone);
+	else
+		zonefs_init_dir_inode(dir, inode);
+	d_add(dentry, inode);
+	dir->i_size++;
+
+	return dentry;
+
+out:
+	dput(dentry);
+
+	return NULL;
+}
+
+static char *zgroups_name[ZONEFS_ZTYPE_MAX] = { "cnv", "seq" };
+
+struct zonefs_zone_data {
+	struct super_block *sb;
+	unsigned int nr_zones[ZONEFS_ZTYPE_MAX];
+	struct blk_zone *zones;
+};
+
+/*
+ * Create a zone group and populate it with zone files.
+ */
+static int zonefs_create_zgroup(struct zonefs_zone_data *zd,
+				enum zonefs_ztype type)
+{
+	struct super_block *sb = zd->sb;
+	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+	struct blk_zone *zone, *next, *end;
+	char name[ZONEFS_NAME_MAX];
+	struct dentry *dir;
+	unsigned int n = 0;
+
+	/* If the group is empty, there is nothing to do */
+	if (!zd->nr_zones[type])
+		return 0;
+
+	dir = zonefs_create_inode(sb->s_root, zgroups_name[type], NULL);
+	if (!dir)
+		return -ENOMEM;
+
+	/*
+	 * The first zone contains the super block: skip it.
+	 */
+	end = zd->zones + blkdev_nr_zones(sb->s_bdev->bd_disk);
+	for (zone = &zd->zones[1]; zone < end; zone = next) {
+
+		next = zone + 1;
+		if (zonefs_zone_type(zone) != type)
+			continue;
+
+		/*
+		 * For conventional zones, contiguous zones can be aggregated
+		 * together to form larger files.
+		 * Note that this overwrites the length of the first zone of
+		 * the set of contiguous zones aggregated together.
+		 * Only zones with the same condition can be agreggated so that
+		 * offline zones are excluded and readonly zones are aggregated
+		 * together into a read only file.
+		 */
+		if (type == ZONEFS_ZTYPE_CNV &&
+		    (sbi->s_features & ZONEFS_F_AGGRCNV)) {
+			for (; next < end; next++) {
+				if (zonefs_zone_type(next) != type ||
+				    next->cond != zone->cond)
+					break;
+				zone->len += next->len;
+			}
+		}
+
+		/*
+		 * Use the file number within its group as file name.
+		 */
+		snprintf(name, ZONEFS_NAME_MAX - 1, "%u", n);
+		if (!zonefs_create_inode(dir, name, zone))
+			return -ENOMEM;
+
+		n++;
+	}
+
+	zonefs_info(sb, "Zone group \"%s\" has %u file%s\n",
+		    zgroups_name[type], n, n > 1 ? "s" : "");
+
+	sbi->s_nr_files[type] = n;
+
+	return 0;
+}
+
+static int zonefs_get_zone_info_cb(struct blk_zone *zone, unsigned int idx,
+				   void *data)
+{
+	struct zonefs_zone_data *zd = data;
+
+	/*
+	 * Count the number of usable zones: the first zone at index 0 contains
+	 * the super block and is ignored.
+	 */
+	switch (zone->type) {
+	case BLK_ZONE_TYPE_CONVENTIONAL:
+		zone->wp = zone->start + zone->len;
+		if (idx)
+			zd->nr_zones[ZONEFS_ZTYPE_CNV]++;
+		break;
+	case BLK_ZONE_TYPE_SEQWRITE_REQ:
+	case BLK_ZONE_TYPE_SEQWRITE_PREF:
+		if (idx)
+			zd->nr_zones[ZONEFS_ZTYPE_SEQ]++;
+		break;
+	default:
+		zonefs_err(zd->sb, "Unsupported zone type 0x%x\n",
+			   zone->type);
+		return -EIO;
+	}
+
+	memcpy(&zd->zones[idx], zone, sizeof(struct blk_zone));
+
+	return 0;
+}
+
+static int zonefs_get_zone_info(struct zonefs_zone_data *zd)
+{
+	struct block_device *bdev = zd->sb->s_bdev;
+	int ret;
+
+	zd->zones = kvcalloc(blkdev_nr_zones(bdev->bd_disk),
+			     sizeof(struct blk_zone), GFP_KERNEL);
+	if (!zd->zones)
+		return -ENOMEM;
+
+	/* Get zones information */
+	ret = blkdev_report_zones(bdev, 0, BLK_ALL_ZONES,
+				  zonefs_get_zone_info_cb, zd);
+	if (ret < 0) {
+		zonefs_err(zd->sb, "Zone report failed %d\n", ret);
+		return ret;
+	}
+
+	if (ret != blkdev_nr_zones(bdev->bd_disk)) {
+		zonefs_err(zd->sb, "Invalid zone report (%d/%u zones)\n",
+			   ret, blkdev_nr_zones(bdev->bd_disk));
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static inline void zonefs_cleanup_zone_info(struct zonefs_zone_data *zd)
+{
+	kvfree(zd->zones);
+}
+
+/*
+ * Read super block information from the device.
+ */
+static int zonefs_read_super(struct super_block *sb)
+{
+	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+	struct zonefs_super *super;
+	u32 crc, stored_crc;
+	struct page *page;
+	struct bio_vec bio_vec;
+	struct bio bio;
+	int ret;
+
+	page = alloc_page(GFP_KERNEL);
+	if (!page)
+		return -ENOMEM;
+
+	bio_init(&bio, &bio_vec, 1);
+	bio.bi_iter.bi_sector = 0;
+	bio_set_dev(&bio, sb->s_bdev);
+	bio_set_op_attrs(&bio, REQ_OP_READ, 0);
+	bio_add_page(&bio, page, PAGE_SIZE, 0);
+
+	ret = submit_bio_wait(&bio);
+	if (ret)
+		goto out;
+
+	super = page_address(page);
+
+	stored_crc = le32_to_cpu(super->s_crc);
+	super->s_crc = 0;
+	crc = crc32(~0U, (unsigned char *)super, sizeof(struct zonefs_super));
+	if (crc != stored_crc) {
+		zonefs_err(sb, "Invalid checksum (Expected 0x%08x, got 0x%08x)",
+			   crc, stored_crc);
+		ret = -EIO;
+		goto out;
+	}
+
+	ret = -EINVAL;
+	if (le32_to_cpu(super->s_magic) != ZONEFS_MAGIC)
+		goto out;
+
+	sbi->s_features = le64_to_cpu(super->s_features);
+	if (sbi->s_features & ~ZONEFS_F_DEFINED_FEATURES) {
+		zonefs_err(sb, "Unknown features set 0x%llx\n",
+			   sbi->s_features);
+		goto out;
+	}
+
+	if (sbi->s_features & ZONEFS_F_UID) {
+		sbi->s_uid = make_kuid(current_user_ns(),
+				       le32_to_cpu(super->s_uid));
+		if (!uid_valid(sbi->s_uid)) {
+			zonefs_err(sb, "Invalid UID feature\n");
+			goto out;
+		}
+	}
+
+	if (sbi->s_features & ZONEFS_F_GID) {
+		sbi->s_gid = make_kgid(current_user_ns(),
+				       le32_to_cpu(super->s_gid));
+		if (!gid_valid(sbi->s_gid)) {
+			zonefs_err(sb, "Invalid GID feature\n");
+			goto out;
+		}
+	}
+
+	if (sbi->s_features & ZONEFS_F_PERM)
+		sbi->s_perm = le32_to_cpu(super->s_perm);
+
+	if (memchr_inv(super->s_reserved, 0, sizeof(super->s_reserved))) {
+		zonefs_err(sb, "Reserved area is being used\n");
+		goto out;
+	}
+
+	uuid_copy(&sbi->s_uuid, &super->s_uuid);
+	ret = 0;
+
+out:
+	__free_page(page);
+
+	return ret;
+}
+
+/*
+ * Check that the device is zoned. If it is, get the list of zones and create
+ * sub-directories and files according to the device zone configuration and
+ * format options.
+ */
+static int zonefs_fill_super(struct super_block *sb, void *data, int silent)
+{
+	struct zonefs_zone_data zd;
+	struct zonefs_sb_info *sbi;
+	struct inode *inode;
+	enum zonefs_ztype t;
+	int ret;
+
+	if (!bdev_is_zoned(sb->s_bdev)) {
+		zonefs_err(sb, "Not a zoned block device\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Initialize super block information: the maximum file size is updated
+	 * when the zone files are created so that the format option
+	 * ZONEFS_F_AGGRCNV which increases the maximum file size of a file
+	 * beyond the zone size is taken into account.
+	 */
+	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+	if (!sbi)
+		return -ENOMEM;
+
+	spin_lock_init(&sbi->s_lock);
+	sb->s_fs_info = sbi;
+	sb->s_magic = ZONEFS_MAGIC;
+	sb->s_maxbytes = 0;
+	sb->s_op = &zonefs_sops;
+	sb->s_time_gran	= 1;
+
+	/*
+	 * The block size is always equal to the device physical sector size to
+	 * ensure that writes on 512e devices (512B logical block and 4KB
+	 * physical block) are always aligned to the device physical blocks
+	 * (as required for writes to sequential zones on ZBC/ZAC disks).
+	 */
+	sb_set_blocksize(sb, bdev_physical_block_size(sb->s_bdev));
+	sbi->s_blocksize_mask = sb->s_blocksize - 1;
+	sbi->s_uid = GLOBAL_ROOT_UID;
+	sbi->s_gid = GLOBAL_ROOT_GID;
+	sbi->s_perm = 0640;
+
+	ret = zonefs_read_super(sb);
+	if (ret)
+		return ret;
+
+	memset(&zd, 0, sizeof(struct zonefs_zone_data));
+	zd.sb = sb;
+	ret = zonefs_get_zone_info(&zd);
+	if (ret)
+		goto out;
+
+	zonefs_info(sb, "Mounting %u zones",
+		    blkdev_nr_zones(sb->s_bdev->bd_disk));
+
+	/* Create root directory inode */
+	ret = -ENOMEM;
+	inode = new_inode(sb);
+	if (!inode)
+		goto out;
+
+	inode->i_ino = get_next_ino();
+	inode->i_mode = S_IFDIR | 0555;
+	inode->i_ctime = inode->i_mtime = inode->i_atime = current_time(inode);
+	inode->i_op = &zonefs_dir_inode_operations;
+	inode->i_fop = &simple_dir_operations;
+	set_nlink(inode, 2);
+
+	sb->s_root = d_make_root(inode);
+	if (!sb->s_root)
+		goto out;
+
+	/* Create and populate files in zone groups directories */
+	for (t = 0; t < ZONEFS_ZTYPE_MAX; t++) {
+		ret = zonefs_create_zgroup(&zd, t);
+		if (ret)
+			break;
+	}
+
+out:
+	zonefs_cleanup_zone_info(&zd);
+
+	return ret;
+}
+
+static struct dentry *zonefs_mount(struct file_system_type *fs_type,
+				   int flags, const char *dev_name, void *data)
+{
+	return mount_bdev(fs_type, flags, dev_name, data, zonefs_fill_super);
+}
+
+static void zonefs_kill_super(struct super_block *sb)
+{
+	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+
+	kfree(sbi);
+	if (sb->s_root)
+		d_genocide(sb->s_root);
+	kill_block_super(sb);
+}
+
+/*
+ * File system definition and registration.
+ */
+static struct file_system_type zonefs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "zonefs",
+	.mount		= zonefs_mount,
+	.kill_sb	= zonefs_kill_super,
+	.fs_flags	= FS_REQUIRES_DEV,
+};
+
+static int __init zonefs_init_inodecache(void)
+{
+	zonefs_inode_cachep = kmem_cache_create("zonefs_inode_cache",
+			sizeof(struct zonefs_inode_info), 0,
+			(SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT),
+			NULL);
+	if (zonefs_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+static void zonefs_destroy_inodecache(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy the inode cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(zonefs_inode_cachep);
+}
+
+static int __init zonefs_init(void)
+{
+	int ret;
+
+	BUILD_BUG_ON(sizeof(struct zonefs_super) != ZONEFS_SUPER_SIZE);
+
+	ret = zonefs_init_inodecache();
+	if (ret)
+		return ret;
+
+	ret = register_filesystem(&zonefs_type);
+	if (ret) {
+		zonefs_destroy_inodecache();
+		return ret;
+	}
+
+	return 0;
+}
+
+static void __exit zonefs_exit(void)
+{
+	zonefs_destroy_inodecache();
+	unregister_filesystem(&zonefs_type);
+}
+
+MODULE_AUTHOR("Damien Le Moal");
+MODULE_DESCRIPTION("Zone file system for zoned block devices");
+MODULE_LICENSE("GPL");
+module_init(zonefs_init);
+module_exit(zonefs_exit);
diff --git a/fs/zonefs/zonefs.h b/fs/zonefs/zonefs.h
new file mode 100644
index 000000000000..0296b3426f7b
--- /dev/null
+++ b/fs/zonefs/zonefs.h
@@ -0,0 +1,169 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Simple zone file system for zoned block devices.
+ *
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ */
+#ifndef __ZONEFS_H__
+#define __ZONEFS_H__
+
+#include <linux/fs.h>
+#include <linux/magic.h>
+#include <linux/uuid.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+
+/*
+ * Maximum length of file names: this only needs to be large enough to fit
+ * the zone group directory names and a decimal value of the start sector of
+ * the zones for file names. 16 characters is plenty.
+ */
+#define ZONEFS_NAME_MAX		16
+
+/*
+ * Zone types: ZONEFS_ZTYPE_SEQ is used for all sequential zone types
+ * defined in linux/blkzoned.h, that is, BLK_ZONE_TYPE_SEQWRITE_REQ and
+ * BLK_ZONE_TYPE_SEQWRITE_PREF.
+ */
+enum zonefs_ztype {
+	ZONEFS_ZTYPE_CNV,
+	ZONEFS_ZTYPE_SEQ,
+	ZONEFS_ZTYPE_MAX,
+};
+
+static inline enum zonefs_ztype zonefs_zone_type(struct blk_zone *zone)
+{
+	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
+		return ZONEFS_ZTYPE_CNV;
+	return ZONEFS_ZTYPE_SEQ;
+}
+
+/*
+ * In-memory inode data.
+ */
+struct zonefs_inode_info {
+	struct inode		i_vnode;
+
+	/* File zone type */
+	enum zonefs_ztype	i_ztype;
+
+	/* File zone start sector (512B unit) */
+	sector_t		i_zsector;
+
+	/* File zone write pointer position (sequential zones only) */
+	loff_t			i_wpoffset;
+
+	/* File maximum size */
+	loff_t			i_max_size;
+
+	/*
+	 * To serialise fully against both syscall and mmap based IO and
+	 * sequential file truncation, two locks are used. For serializing
+	 * zonefs_seq_file_truncate() against zonefs_iomap_begin(), that is,
+	 * file truncate operations against block mapping, i_truncate_mutex is
+	 * used. i_truncate_mutex also protects against concurrent accesses
+	 * and changes to the inode private data, and in particular changes to
+	 * a sequential file size on completion of direct IO writes.
+	 * Serialization of mmap read IOs with truncate and syscall IO
+	 * operations is done with i_mmap_sem in addition to i_truncate_mutex.
+	 * Only zonefs_seq_file_truncate() takes both lock (i_mmap_sem first,
+	 * i_truncate_mutex second).
+	 */
+	struct mutex		i_truncate_mutex;
+	struct rw_semaphore	i_mmap_sem;
+};
+
+static inline struct zonefs_inode_info *ZONEFS_I(struct inode *inode)
+{
+	return container_of(inode, struct zonefs_inode_info, i_vnode);
+}
+
+/*
+ * On-disk super block (block 0).
+ */
+#define ZONEFS_SUPER_SIZE	4096
+struct zonefs_super {
+
+	/* Magic number */
+	__le32		s_magic;
+
+	/* Checksum */
+	__le32		s_crc;
+
+	/* Features */
+	__le64		s_features;
+
+	/* 128-bit uuid */
+	uuid_t		s_uuid;
+
+	/* UID/GID to use for files */
+	__le32		s_uid;
+	__le32		s_gid;
+
+	/* File permissions */
+	__le32		s_perm;
+
+	/* Padding to ZONEFS_SUPER_SIZE bytes */
+	__u8		s_reserved[4052];
+
+} __packed;
+
+/*
+ * Feature flags: used on disk in the s_features field of struct zonefs_super
+ * and in-memory in the s_feartures field of struct zonefs_sb_info.
+ */
+enum zonefs_features {
+	/*
+	 * Aggregate contiguous conventional zones into a single file.
+	 */
+	ZONEFS_F_AGGRCNV = 1ULL << 0,
+	/*
+	 * Use super block specified UID for files instead of default.
+	 */
+	ZONEFS_F_UID = 1ULL << 1,
+	/*
+	 * Use super block specified GID for files instead of default.
+	 */
+	ZONEFS_F_GID = 1ULL << 2,
+	/*
+	 * Use super block specified file permissions instead of default 640.
+	 */
+	ZONEFS_F_PERM = 1ULL << 3,
+};
+
+#define ZONEFS_F_DEFINED_FEATURES \
+	(ZONEFS_F_AGGRCNV | ZONEFS_F_UID | ZONEFS_F_GID | ZONEFS_F_PERM)
+
+/*
+ * In-memory Super block information.
+ */
+struct zonefs_sb_info {
+
+	spinlock_t		s_lock;
+
+	unsigned long long	s_features;
+	kuid_t			s_uid;
+	kgid_t			s_gid;
+	umode_t			s_perm;
+	uuid_t			s_uuid;
+	loff_t			s_blocksize_mask;
+
+	unsigned int		s_nr_files[ZONEFS_ZTYPE_MAX];
+
+	loff_t			s_blocks;
+	loff_t			s_used_blocks;
+};
+
+static inline struct zonefs_sb_info *ZONEFS_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+#define zonefs_info(sb, format, args...)	\
+	pr_info("zonefs (%s): " format, sb->s_id, ## args)
+#define zonefs_err(sb, format, args...)	\
+	pr_err("zonefs (%s) ERROR: " format, sb->s_id, ## args)
+#define zonefs_warn(sb, format, args...)	\
+	pr_warn("zonefs (%s) WARN: " format, sb->s_id, ## args)
+
+#endif
diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h
index 3ac436376d79..d78064007b17 100644
--- a/include/uapi/linux/magic.h
+++ b/include/uapi/linux/magic.h
@@ -87,6 +87,7 @@
 #define NSFS_MAGIC		0x6e736673
 #define BPF_FS_MAGIC		0xcafe4a11
 #define AAFS_MAGIC		0x5a3c69f0
+#define ZONEFS_MAGIC		0x5a4f4653
 
 /* Since UDF 2.01 is ISO 13346 based... */
 #define UDF_SUPER_MAGIC		0x15013346
