On Tue, Sep 03, 2019 at 12:59:17AM +0000, Damien Le Moal wrote:
> Hi Darrick,
>
> Any comments on this new version ?
I took a brief glance a few days ago and it looked ok wrt the iomap
parts. I'm assuming you received the same complaint from the kbuild
robot as I did?
> Should I wait for the iomap code to make it to 5.4 first before trying to get
> this new FS included ?
Given that the merge window apparently won't close until Sept. 29, that
gives us more time to make any more minor tweaks.
(That means 80% of a "Go for it" but I'll look more closely tomorrow ;))
--D
> Best regards.
>
> On 2019/08/26 15:58, Damien Le Moal wrote:
> > zonefs is a very simple file system exposing each zone of a zoned
> > block device as a file. zonefs is in fact closer to a raw block device
> > access interface than to a full feature POSIX file system.
> >
> > The goal of zonefs is to simplify implementation of zoned block device
> > raw access by applications by allowing switching to the well known POSIX
> > file API rather than relying on direct block device file ioctls and
> > read/write. Zonefs, for instance, greatly simplifies the implementation
> > of LSM (log-structured merge) tree structures (such as used in RocksDB
> > and LevelDB) on zoned block devices by allowing SSTables to be stored in
> > a zone file similarly to a regular file system architecture, hence
> > reducing the amount of change needed in the application.
> >
> > Zonefs on-disk metadata is reduced to a super block to store a magic
> > number, a uuid and optional features flags and values. On mount, zonefs
> > uses blkdev_report_zones() to obtain the device zone configuration and
> > populates the mount point with a static file tree solely based on this
> > information. E.g. file sizes come from zone write pointer offset managed
> > by the device itself.
> >
> > The zone files created on mount have the following characteristics.
> > 1) Files representing zones of the same type are grouped together
> > under a common directory:
> > * For conventional zones, the directory "cnv" is used.
> > * For sequential write zones, the directory "seq" is used.
> > These two directories are the only directories that exist in zonefs.
> > Users cannot create other directories and cannot rename nor delete
> > the "cnv" and "seq" directories.
> > 2) The name of zone files is by default the number of the file within
> > the zone type directory, in order of increasing zone start sector.
> > 3) The size of conventional zone files is fixed to the device zone size.
> > Conventional zone files cannot be truncated.
> > 4) The size of sequential zone files represent the file zone write
> > pointer position relative to the zone start sector. Truncating these
> > files is allowed only down to 0, in wich case, the zone is reset to
> > rewind the file zone write pointer position to the start of the zone.
> > 5) All read and write operations to files are not allowed beyond the
> > file zone size. Any access exceeding the zone size is failed with
> > the -EFBIG error.
> > 6) Creating, deleting, renaming or modifying any attribute of files
> > and directories is not allowed. The only exception being the file
> > size of sequential zone files which can be modified by write
> > operations or truncation to 0.
> >
> > Several optional features of zonefs can be enabled at format time.
> > * Conventional zone aggregation: contiguous conventional zones can be
> > agregated into a single larger file instead of multiple per-zone
> > files.
> > * File naming: the default file number file name can be switched to
> > using the base-10 value of the file zone start sector.
> > * File ownership: The owner UID and GID of zone files is by default 0
> > (root) but can be changed to any valid UID/GID.
> > * File access permissions: the default 640 access permissions can be
> > changed.
> >
> > The mkzonefs tool is used to format zonefs. This tool is available
> > on Github at: git@xxxxxxxxxx:damien-lemoal/zonefs-tools.git.
> > zonefs-tools includes a simple test suite which can be run against any
> > zoned block device, including null_blk block device created with zoned
> > mode.
> >
> > Example: the following formats a host-managed SMR HDD with the
> > conventional zone aggregation feature enabled.
> >
> > mkzonefs -o aggr_cnv /dev/sdX
> > mount -t zonefs /dev/sdX /mnt
> > ls -l /mnt/
> > total 0
> > dr-xr-xr-x 2 root root 0 Apr 11 13:00 cnv
> > dr-xr-xr-x 2 root root 0 Apr 11 13:00 seq
> >
> > ls -l /mnt/cnv
> > total 137363456
> > -rw-rw---- 1 root root 140660178944 Apr 11 13:00 0
> >
> > ls -Fal -v /mnt/seq
> > total 14511243264
> > dr-xr-xr-x 2 root root 15942528 Jul 10 11:53 ./
> > drwxr-xr-x 4 root root 1152 Jul 10 11:53 ../
> > -rw-r----- 1 root root 0 Jul 10 11:53 0
> > -rw-r----- 1 root root 33554432 Jul 10 13:43 1
> > -rw-r----- 1 root root 0 Jul 10 11:53 2
> > -rw-r----- 1 root root 0 Jul 10 11:53 3
> > ...
> >
> > The aggregated conventional zone file can be used as a regular file.
> > Operations such as the following work.
> >
> > mkfs.ext4 /mnt/cnv/0
> > mount -o loop /mnt/cnv/0 /data
> >
> > Contains contributions from Johannes Thumshirn <jthumshirn@xxxxxxx>
> > and Christoph Hellwig <hch@xxxxxx>.
> >
> > Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>
> > ---
> > Changes from v3:
> > * Enhanced super block features and reserved field handling as suggested
> > by Darrick.
> > * Expose offline zones as non-accessible files to avoid zone to file
> > name mapping changes.
> >
> > Changes from v2:
> > * Addressed comments from Darrick: Typo, added checksum to super block,
> > enhance cheks of the super block fields validity (used reserved bytes
> > and unknown features bits)
> > * Rebased on XFS tree iomap-for-next branch
> >
> > Changes from v1:
> > * Rebased on latest iomap branch iomap-5.4-merge of XFS tree at
> > git://git.kernel.org/pub/scm/fs/xfs/xfs-linux.git
> > * Addressed all comments from Dave Chinner and others
> >
> > MAINTAINERS | 10 +
> > fs/Kconfig | 1 +
> > fs/Makefile | 1 +
> > fs/zonefs/Kconfig | 9 +
> > fs/zonefs/Makefile | 4 +
> > fs/zonefs/super.c | 1093 ++++++++++++++++++++++++++++++++++++
> > fs/zonefs/zonefs.h | 185 ++++++
> > include/uapi/linux/magic.h | 1 +
> > 8 files changed, 1304 insertions(+)
> > create mode 100644 fs/zonefs/Kconfig
> > create mode 100644 fs/zonefs/Makefile
> > create mode 100644 fs/zonefs/super.c
> > create mode 100644 fs/zonefs/zonefs.h
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 6426db5198f0..a1b2c9836073 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -17793,6 +17793,16 @@ L: linux-kernel@xxxxxxxxxxxxxxx
> > S: Maintained
> > F: arch/x86/kernel/cpu/zhaoxin.c
> >
> > +ZONEFS FILESYSTEM
> > +M: Damien Le Moal <damien.lemoal@xxxxxxx>
> > +M: Naohiro Aota <naohiro.aota@xxxxxxx>
> > +R: Johannes Thumshirn <jth@xxxxxxxxxx>
> > +L: linux-fsdevel@xxxxxxxxxxxxxxx
> > +T: git git@xxxxxxxxxx:damien-lemoal/zonefs.git
> > +S: Maintained
> > +F: Documentation/filesystems/zonefs.txt
> > +F: fs/zonefs/
> > +
> > ZPOOL COMPRESSED PAGE STORAGE API
> > M: Dan Streetman <ddstreet@xxxxxxxx>
> > L: linux-mm@xxxxxxxxx
> > 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
> >
>
>
> --
> Damien Le Moal
> Western Digital Research
