diff --git a/MAINTAINERS b/MAINTAINERS
index 6426db5198f0..a1b2c9836073 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17793,6 +17793,16 @@ 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@github.com:damien-lemoal/zonefs.git
+S:	Maintained
+F:	Documentation/filesystems/zonefs.txt
+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 bfb1c6095c7a..dcaf3e07680f 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 d60089fd689b..7d3c90e1ad79 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -130,3 +130,4 @@ obj-$(CONFIG_F2FS_FS)		+= f2fs/
 obj-$(CONFIG_CEPH_FS)		+= ceph/
 obj-$(CONFIG_PSTORE)		+= pstore/
 obj-$(CONFIG_EFIVAR_FS)		+= efivarfs/
+obj-$(CONFIG_ZONEFS_FS)		+= zonefs/
diff --git a/fs/zonefs/Kconfig b/fs/zonefs/Kconfig
new file mode 100644
index 000000000000..6490547e9763
--- /dev/null
+++ b/fs/zonefs/Kconfig
@@ -0,0 +1,9 @@
+config ZONEFS_FS
+	tristate "zonefs filesystem support"
+	depends on BLOCK
+	depends on BLK_DEV_ZONED
+	help
+	  zonefs is a simple File System which exposes zones of a zoned block
+	  device as files.
+
+	  If unsure, say N.
diff --git a/fs/zonefs/Makefile b/fs/zonefs/Makefile
new file mode 100644
index 000000000000..75a380aa1ae1
--- /dev/null
+++ b/fs/zonefs/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(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..8659878c6aec
--- /dev/null
+++ b/fs/zonefs/super.c
@@ -0,0 +1,1093 @@
+// 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 zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	loff_t max_isize = zonefs_file_max_size(inode);
+	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(zonefs_file_is_seq(inode) && (flags & IOMAP_WRITE) &&
+			 !(flags & IOMAP_DIRECT)))
+		return -EIO;
+
+	/* An IO cannot exceed the zone size */
+	if (offset >= max_isize)
+		return -EFBIG;
+
+	/* All blocks are always mapped */
+	mutex_lock(&zi->i_truncate_mutex);
+	isize = i_size_read(inode);
+	if (offset >= isize) {
+		length = min(length, max_isize - offset);
+		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 = (zonefs_file_start_sector(inode) << 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_file_max_size(inode),
+				  0, &wpc->iomap);
+}
+
+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 int zonefs_seq_file_truncate(struct inode *inode)
+{
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	int ret;
+
+	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);
+
+	ret = blkdev_reset_zones(inode->i_sb->s_bdev,
+				 zonefs_file_start_sector(inode),
+				 zonefs_file_max_size(inode) >> SECTOR_SHIFT,
+				 GFP_NOFS);
+	if (ret) {
+		zonefs_err(inode->i_sb,
+			   "Reset zone at %llu failed %d",
+			   zonefs_file_start_sector(inode),
+			   ret);
+	} else {
+		truncate_setsize(inode, 0);
+		zi->i_wpoffset = 0;
+	}
+
+	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;
+
+	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_file_is_conv(inode))
+			return -EPERM;
+
+		/*
+		 * For sequential zone files, we can only allow truncating to
+		 * 0 size which is equivalent to a zone reset.
+		 */
+		if (iattr->ia_size != 0)
+			return -EPERM;
+
+		ret = zonefs_seq_file_truncate(inode);
+		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_conv_file_write_and_wait(struct file *file, loff_t start,
+					   loff_t end)
+{
+	int ret;
+
+	ret = file_write_and_wait_range(file, start, end);
+	if (ret)
+		return ret;
+
+	return file_check_and_advance_wb_err(file);
+}
+
+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_file_is_conv(inode))
+		ret = zonefs_conv_file_write_and_wait(file, start, end);
+
+	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_file_is_seq(file_inode(file)) &&
+	    (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_inode_info *zi = ZONEFS_I(inode);
+	struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
+	loff_t max_pos;
+	size_t count;
+	ssize_t ret;
+
+	if (iocb->ki_pos >= zonefs_file_max_size(inode))
+		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) {
+		/*
+		 * Direct IO reads must be aligned to device physical sector
+		 * size.
+		 */
+		if ((iocb->ki_pos | count) & sbi->s_blocksize_mask) {
+			ret = -EINVAL;
+		} else {
+			file_accessed(iocb->ki_filp);
+			ret = iomap_dio_rw(iocb, to, &zonefs_iomap_ops, NULL);
+		}
+	} else {
+		ret = generic_file_read_iter(iocb, to);
+	}
+
+out:
+	inode_unlock_shared(inode);
+
+	return ret;
+}
+
+/*
+ * 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 super_block *sb = inode->i_sb;
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	sector_t sector = zi->i_zsector;
+	unsigned int nofs_flag;
+	struct blk_zone zone;
+	int n = 1, ret;
+	loff_t pos;
+
+	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 to no end up recusrsing into the FS on
+	 * memory allocation.
+	 */
+	nofs_flag = memalloc_nofs_save();
+	ret = blkdev_report_zones(sb->s_bdev, sector, &zone, &n);
+	memalloc_nofs_restore(nofs_flag);
+
+	if (ret || !n) {
+		if (!n)
+			ret = -EIO;
+		zonefs_err(sb, "Get zone %llu report failed %d\n",
+			   sector, ret);
+		return ret;
+	}
+
+	pos = (zone.wp - zone.start) << SECTOR_SHIFT;
+	zi->i_wpoffset = pos;
+	if (i_size_read(inode) != pos)
+		i_size_write(inode, pos);
+
+	return error;
+}
+
+static int zonefs_file_dio_write_end(struct kiocb *iocb, ssize_t size,
+				     unsigned int flags)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	int ret = 0;
+
+	/*
+	 * Conventional zone file size is fixed to the zone size so there
+	 * is no need to do anything.
+	 */
+	if (zonefs_file_is_conv(inode))
+		return 0;
+
+	mutex_lock(&zi->i_truncate_mutex);
+
+	if (size < 0) {
+		ret = zonefs_seq_file_write_failed(inode, size);
+	} else {
+		/* Update seq file size */
+		if (i_size_read(inode) < iocb->ki_pos + size)
+			i_size_write(inode, iocb->ki_pos + size);
+	}
+
+	mutex_unlock(&zi->i_truncate_mutex);
+
+	return ret;
+}
+
+static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
+	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, zonefs_file_max_size(inode) - 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 (zonefs_file_is_seq(inode) &&
+	    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_file_dio_write_end);
+	if (zonefs_file_is_seq(inode) &&
+	    (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);
+	size_t count;
+	ssize_t ret;
+
+	/*
+	 * Direct IO writes are mandatory for sequential zones so that the
+	 * write IO order is preserved.
+	 */
+	if (zonefs_file_is_seq(inode))
+		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, zonefs_file_max_size(inode) - 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_file_max_size(inode))
+		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;
+
+	mutex_init(&zi->i_truncate_mutex);
+	init_rwsem(&zi->i_mmap_sem);
+	inode_init_once(&zi->i_vnode);
+
+	return &zi->i_vnode;
+}
+
+static void zonefs_free_inode(struct inode *inode)
+{
+	kmem_cache_free(zonefs_inode_cachep, ZONEFS_I(inode));
+}
+
+static struct dentry *zonefs_create_inode(struct dentry *parent,
+					  const char *name,
+					  struct blk_zone *zone)
+{
+	struct zonefs_sb_info *sbi = ZONEFS_SB(parent->d_sb);
+	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_dput;
+
+	inode->i_ino = get_next_ino();
+	if (zone) {
+		struct zonefs_inode_info *zi = ZONEFS_I(inode);
+
+		/*
+		 * Zone file: for read-only zones, do not allow writes.
+		 * For offline zones, disable all accesses and set the file
+		 * size to 0.
+		 */
+		inode->i_mode = S_IFREG;
+		switch (zone->cond) {
+		case BLK_ZONE_COND_READONLY:
+			inode->i_mode |= sbi->s_perm & ~(0222); /* S_IWUGO */
+		case BLK_ZONE_COND_OFFLINE:
+			break;
+		default:
+			inode->i_mode |= sbi->s_perm;
+		}
+		inode->i_uid = sbi->s_uid;
+		inode->i_gid = sbi->s_gid;
+		zi->i_ztype = zonefs_zone_type(zone);
+		zi->i_zsector = zone->start;
+		zi->i_max_size = zone->len << SECTOR_SHIFT;
+
+		if (zone->cond == BLK_ZONE_COND_OFFLINE)
+			zi->i_wpoffset = 0;
+		else if (zonefs_file_is_conv(inode))
+			zi->i_wpoffset = zi->i_max_size;
+		else
+			zi->i_wpoffset =
+				(zone->wp - zone->start) << SECTOR_SHIFT;
+
+		inode->i_size = zi->i_wpoffset;
+		inode->i_blocks = zone->len;
+		inode->i_fop = &zonefs_file_operations;
+		inode->i_op = &zonefs_file_inode_operations;
+		inode->i_mapping->a_ops = &zonefs_file_aops;
+		inode->i_mapping->a_ops = &zonefs_file_aops;
+	} else {
+		/* Zone group directory */
+		inode_init_owner(inode, dir, S_IFDIR | 0555);
+		inode->i_fop = &simple_dir_operations;
+		inode->i_op = &simple_dir_inode_operations;
+		set_nlink(inode, 2);
+		inc_nlink(dir);
+	}
+	inode->i_ctime = inode->i_mtime = inode->i_atime = dir->i_ctime;
+
+	d_add(dentry, inode);
+	d_inode(parent)->i_size += sizeof(struct dentry);
+
+	return dentry;
+
+out_dput:
+	dput(dentry);
+	return NULL;
+}
+
+/*
+ * 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);
+	sector_t nr_sectors = sb->s_bdev->bd_part->nr_sects;
+	enum zonefs_ztype t;
+	u64 fsid;
+
+	buf->f_type = ZONEFS_MAGIC;
+	buf->f_bsize = dentry->d_sb->s_blocksize;
+	buf->f_namelen = ZONEFS_NAME_MAX;
+
+	buf->f_blocks = nr_sectors >> (sb->s_blocksize_bits - SECTOR_SHIFT);
+	buf->f_bfree = 0;
+	buf->f_bavail = 0;
+
+	buf->f_files = blkdev_nr_zones(sb->s_bdev);
+	for (t = 0 ; t < ZONEFS_ZTYPE_MAX; t++) {
+		if (sbi->s_nr_zones[t])
+			buf->f_files++;
+	}
+	buf->f_ffree = 0;
+
+	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 char *zgroups_name[ZONEFS_ZTYPE_MAX] = {
+	"cnv",
+	"seq"
+};
+
+/*
+ * Create a zone group and populate it with zone files.
+ */
+static int zonefs_create_zgroup(struct super_block *sb, struct blk_zone *zones,
+				enum zonefs_ztype type)
+{
+	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+	struct blk_zone *zone, *next, *end;
+	char name[ZONEFS_NAME_MAX];
+	unsigned int nr_files = 0;
+	struct dentry *dir;
+
+	/* If the group is empty, nothing to do */
+	if (!sbi->s_nr_zones[type])
+		return 0;
+
+	dir = zonefs_create_inode(sb->s_root, zgroups_name[type], NULL);
+	if (!dir)
+		return -ENOMEM;
+
+	/*
+	 * Note: The first zone contains the super block: skip it.
+	 */
+	end = zones + blkdev_nr_zones(sb->s_bdev);
+	for (zone = &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 &&
+		    zonefs_has_feature(sbi, ZONEFS_F_AGRCNV)) {
+			for (; next < end; next++) {
+				if (zonefs_zone_type(next) != type ||
+				    next->cond != zone->cond)
+					break;
+				zone->len += next->len;
+			}
+		}
+
+		if (zonefs_has_feature(sbi, ZONEFS_F_STARTSECT_NAME))
+			/* Use zone start sector as file names */
+			snprintf(name, ZONEFS_NAME_MAX - 1, "%llu",
+				 zone->start);
+		else
+			/* Use file number as file names */
+			snprintf(name, ZONEFS_NAME_MAX - 1, "%u", nr_files);
+		nr_files++;
+
+		if (!zonefs_create_inode(dir, name, zone))
+			return -ENOMEM;
+	}
+
+	zonefs_info(sb, "Zone group %d (%s), %u zones -> %u file%s\n",
+		    type, zgroups_name[type], sbi->s_nr_zones[type],
+		    nr_files, nr_files > 1 ? "s" : "");
+
+	return 0;
+}
+
+static struct blk_zone *zonefs_get_zone_info(struct super_block *sb)
+{
+	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+	struct block_device *bdev = sb->s_bdev;
+	sector_t nr_sectors = bdev->bd_part->nr_sects;
+	unsigned int i, n, nr_zones = 0;
+	struct blk_zone *zones, *zone;
+	sector_t sector = 0;
+	int ret;
+
+	zones = kvcalloc(blkdev_nr_zones(bdev),
+			 sizeof(struct blk_zone), GFP_KERNEL);
+	if (!zones)
+		return ERR_PTR(-ENOMEM);
+
+	/* Get zones information */
+	zone = zones;
+	while (nr_zones < blkdev_nr_zones(bdev) &&
+	       sector < nr_sectors) {
+
+		n = blkdev_nr_zones(bdev) - nr_zones;
+		ret = blkdev_report_zones(bdev, sector, zone, &n);
+		if (ret) {
+			zonefs_err(sb, "Zone report failed %d\n", ret);
+			goto err;
+		}
+		if (!n) {
+			zonefs_err(sb, "No zones reported\n");
+			ret = -EIO;
+			goto err;
+		}
+
+		for (i = 0; i < n; i++) {
+			switch (zone->type) {
+			case BLK_ZONE_TYPE_CONVENTIONAL:
+				zone->wp = zone->start + zone->len;
+				if (zone > zones)
+					sbi->s_nr_zones[ZONEFS_ZTYPE_CNV]++;
+				break;
+			case BLK_ZONE_TYPE_SEQWRITE_REQ:
+			case BLK_ZONE_TYPE_SEQWRITE_PREF:
+				if (zone > zones)
+					sbi->s_nr_zones[ZONEFS_ZTYPE_SEQ]++;
+				break;
+			default:
+				zonefs_err(sb, "Unsupported zone type 0x%x\n",
+					   zone->type);
+				ret = -EIO;
+				goto err;
+			}
+			sector += zone->len;
+			zone++;
+		}
+
+		nr_zones += n;
+	}
+
+	if (sector < nr_sectors ||
+	    nr_zones != blkdev_nr_zones(bdev)) {
+		zonefs_err(sb, "Invalid zone report\n");
+		ret = -EIO;
+		goto err;
+	}
+
+	return zones;
+
+err:
+	kvfree(zones);
+	return ERR_PTR(ret);
+}
+
+/*
+ * 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;
+	struct bio bio;
+	struct bio_vec bio_vec;
+	struct page *page;
+	u32 crc, stored_crc;
+	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 = super->s_crc;
+	super->s_crc = 0;
+	crc = crc32_le(ZONEFS_MAGIC, (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 (zonefs_has_feature(sbi, 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 (zonefs_has_feature(sbi, 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 (zonefs_has_feature(sbi, 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.
+ */
+static int zonefs_fill_super(struct super_block *sb, void *data, int silent)
+{
+	struct zonefs_sb_info *sbi;
+	struct blk_zone *zones;
+	struct inode *inode;
+	enum zonefs_ztype t;
+	int ret;
+
+	/* Check device type */
+	if (!bdev_is_zoned(sb->s_bdev)) {
+		zonefs_err(sb, "Not a zoned block device\n");
+		return -EINVAL;
+	}
+
+	/* Initialize super block information */
+	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+	if (!sbi)
+		return -ENOMEM;
+
+	sb->s_fs_info = sbi;
+	sb->s_magic = ZONEFS_MAGIC;
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	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 disks (512B logical block and 4KB
+	 * physical block) are always aligned.
+	 */
+	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; /* S_IRUSR | S_IWUSR | S_IRGRP */
+
+	ret = zonefs_read_super(sb);
+	if (ret)
+		return ret;
+
+	zones = zonefs_get_zone_info(sb);
+	if (IS_ERR(zones))
+		return PTR_ERR(zones);
+
+	pr_info("zonefs: Mounting %s, %u zones",
+		sb->s_id, blkdev_nr_zones(sb->s_bdev));
+
+	/* 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 | 0755;
+	inode->i_ctime = inode->i_mtime = inode->i_atime = current_time(inode);
+	inode->i_op = &simple_dir_inode_operations;
+	inode->i_fop = &simple_dir_operations;
+	inode->i_size = sizeof(struct dentry) * 2;
+	set_nlink(inode, 2);
+
+	sb->s_root = d_make_root(inode);
+	if (!sb->s_root)
+		goto out;
+
+	/* Create and populate zone groups */
+	for (t = ZONEFS_ZTYPE_CNV; t < ZONEFS_ZTYPE_MAX; t++) {
+		ret = zonefs_create_zgroup(sb, zones, t);
+		if (ret)
+			break;
+	}
+
+out:
+	kvfree(zones);
+
+	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..5338663711b4
--- /dev/null
+++ b/fs/zonefs/zonefs.h
@@ -0,0 +1,185 @@
+/* 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;
+}
+
+/*
+ * Inode private data.
+ */
+struct zonefs_inode_info {
+	struct inode		i_vnode;
+	enum zonefs_ztype	i_ztype;
+	sector_t		i_zsector;
+	loff_t			i_wpoffset;
+	loff_t			i_max_size;
+	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);
+}
+
+static inline bool zonefs_file_is_conv(struct inode *inode)
+{
+	return ZONEFS_I(inode)->i_ztype == ZONEFS_ZTYPE_CNV;
+}
+
+static inline bool zonefs_file_is_seq(struct inode *inode)
+{
+	return ZONEFS_I(inode)->i_ztype == ZONEFS_ZTYPE_SEQ;
+}
+
+/*
+ * Start sector on disk of a file zone.
+ */
+static inline loff_t zonefs_file_start_sector(struct inode *inode)
+{
+	return ZONEFS_I(inode)->i_zsector;
+}
+
+/*
+ * Maximum possible size of a file (i.e. the zone size).
+ */
+static inline loff_t zonefs_file_max_size(struct inode *inode)
+{
+	return ZONEFS_I(inode)->i_max_size;
+}
+
+/*
+ * 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 {
+	/*
+	 * Use a zone start sector value as file name.
+	 */
+	__ZONEFS_F_STARTSECT_NAME,
+	/*
+	 * Aggregate contiguous conventional zones into a single file.
+	 */
+	__ZONEFS_F_AGRCNV,
+	/*
+	 * Use super block specified UID for files instead of default.
+	 */
+	__ZONEFS_F_UID,
+	/*
+	 * Use super block specified GID for files instead of default.
+	 */
+	__ZONEFS_F_GID,
+	/*
+	 * Use super block specified file permissions instead of default 640.
+	 */
+	__ZONEFS_F_PERM,
+};
+
+#define ZONEFS_F_STARTSECT_NAME	(1ULL << __ZONEFS_F_STARTSECT_NAME)
+#define ZONEFS_F_AGRCNV		(1ULL << __ZONEFS_F_AGRCNV)
+#define ZONEFS_F_UID		(1ULL << __ZONEFS_F_UID)
+#define ZONEFS_F_GID		(1ULL << __ZONEFS_F_GID)
+#define ZONEFS_F_PERM		(1ULL << __ZONEFS_F_PERM)
+
+#define ZONEFS_F_DEFINED_FEATURES \
+	(ZONEFS_F_STARTSECT_NAME | ZONEFS_F_AGRCNV | \
+	 ZONEFS_F_UID | ZONEFS_F_GID | ZONEFS_F_PERM)
+
+/*
+ * In-memory Super block information.
+ */
+struct zonefs_sb_info {
+
+	unsigned long long	s_features;
+	kuid_t			s_uid;		/* File owner UID */
+	kgid_t			s_gid;		/* File owner GID */
+	umode_t			s_perm;		/* File permissions */
+	uuid_t			s_uuid;
+
+	loff_t			s_blocksize_mask;
+	unsigned int		s_nr_zones[ZONEFS_ZTYPE_MAX];
+};
+
+static inline struct zonefs_sb_info *ZONEFS_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+static inline bool zonefs_has_feature(struct zonefs_sb_info *sbi,
+				      enum zonefs_features f)
+{
+	return sbi->s_features & f;
+}
+
+#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 1274c692e59c..3be20c774142 100644
--- a/include/uapi/linux/magic.h
+++ b/include/uapi/linux/magic.h
@@ -86,6 +86,7 @@
 #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
