author: Damien Le Moal <damien.lemoal@wdc.com> 2019-12-25 16:07:44 +0900
committer: Damien Le Moal <damien.lemoal@wdc.com> 2020-02-07 14:39:38 +0900
commit: 8dcc1a9d90c10fa4143e5c17821082e5e60e46a1
parent: d5226fa6dbae0569ee43ecfc08bdcd6770fc4755
Commit Summary:
Diffstat:
4 files changed, 1372 insertions, 0 deletions
diff --git a/fs/zonefs/Kconfig b/fs/zonefs/Kconfig
new file mode 100644
index 000000000000..fb87ad372e29
--- /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..8bc6ef82d693
--- /dev/null
+++ b/fs/zonefs/super.c
@@ -0,0 +1,1439 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Simple file system for zoned block devices exposing zones as files.
+ *
+ * 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_inode_info *zi = ZONEFS_I(inode);
+ struct super_block *sb = inode->i_sb;
+ loff_t isize;
+
+ /* All I/Os should always be within the file maximum size */
+ if (WARN_ON_ONCE(offset + length > zi->i_max_size))
+ return -EIO;
+
+ /*
+ * Sequential zones can only accept direct writes. This is already
+ * checked when writes are issued, so warn if we see a page writeback
+ * operation.
+ */
+ if (WARN_ON_ONCE(zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
+ (flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT)))
+ return -EIO;
+
+ /*
+ * For conventional zones, all blocks are always mapped. For sequential
+ * zones, all blocks after always mapped below the inode size (zone
+ * write pointer) and unwriten beyond.
+ */
+ mutex_lock(&zi->i_truncate_mutex);
+ isize = i_size_read(inode);
+ if (offset >= isize)
+ iomap->type = IOMAP_UNWRITTEN;
+ else
+ iomap->type = IOMAP_MAPPED;
+ if (flags & IOMAP_WRITE)
+ length = zi->i_max_size - offset;
+ else
+ length = min(length, isize - offset);
+ mutex_unlock(&zi->i_truncate_mutex);
+
+ iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
+ iomap->length = ALIGN(offset + length, sb->s_blocksize) - 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);
+}
+
+/*
+ * Map blocks for page writeback. This is used only on conventional zone files,
+ * which implies that the page range can only be within the fixed inode size.
+ */
+static int zonefs_map_blocks(struct iomap_writepage_ctx *wpc,
+ struct inode *inode, loff_t offset)
+{
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+
+ if (WARN_ON_ONCE(zi->i_ztype != ZONEFS_ZTYPE_CNV))
+ return -EIO;
+ if (WARN_ON_ONCE(offset >= i_size_read(inode)))
+ return -EIO;
+
+ /* If the mapping is already OK, nothing needs to be done */
+ if (offset >= wpc->iomap.offset &&
+ offset < wpc->iomap.offset + wpc->iomap.length)
+ return 0;
+
+ return zonefs_iomap_begin(inode, offset, zi->i_max_size - offset,
+ IOMAP_WRITE, &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);
+ loff_t nr_blocks;
+
+ if (new_isize == old_isize)
+ return;
+
+ spin_lock(&sbi->s_lock);
+
+ /*
+ * This may be called for an update after an IO error.
+ * So beware of the values seen.
+ */
+ if (new_isize < old_isize) {
+ nr_blocks = (old_isize - new_isize) >> sb->s_blocksize_bits;
+ if (sbi->s_used_blocks > nr_blocks)
+ sbi->s_used_blocks -= nr_blocks;
+ else
+ sbi->s_used_blocks = 0;
+ } else {
+ sbi->s_used_blocks +=
+ (new_isize - old_isize) >> sb->s_blocksize_bits;
+ if (sbi->s_used_blocks > sbi->s_blocks)
+ sbi->s_used_blocks = sbi->s_blocks;
+ }
+
+ spin_unlock(&sbi->s_lock);
+}
+
+/*
+ * Check a zone condition and adjust its file inode access permissions for
+ * offline and readonly zones. Return the inode size corresponding to the
+ * amount of readable data in the zone.
+ */
+static loff_t zonefs_check_zone_condition(struct inode *inode,
+ struct blk_zone *zone, bool warn)
+{
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+
+ switch (zone->cond) {
+ case BLK_ZONE_COND_OFFLINE:
+ /*
+ * Dead zone: make the inode immutable, disable all accesses
+ * and set the file size to 0 (zone wp set to zone start).
+ */
+ if (warn)
+ zonefs_warn(inode->i_sb, "inode %lu: offline zone\n",
+ inode->i_ino);
+ inode->i_flags |= S_IMMUTABLE;
+ inode->i_mode &= ~0777;
+ zone->wp = zone->start;
+ return 0;
+ case BLK_ZONE_COND_READONLY:
+ /* Do not allow writes in read-only zones */
+ if (warn)
+ zonefs_warn(inode->i_sb, "inode %lu: read-only zone\n",
+ inode->i_ino);
+ inode->i_flags |= S_IMMUTABLE;
+ inode->i_mode &= ~0222;
+ /* fallthrough */
+ default:
+ if (zi->i_ztype == ZONEFS_ZTYPE_CNV)
+ return zi->i_max_size;
+ return (zone->wp - zone->start) << SECTOR_SHIFT;
+ }
+}
+
+struct zonefs_ioerr_data {
+ struct inode *inode;
+ bool write;
+};
+
+static int zonefs_io_error_cb(struct blk_zone *zone, unsigned int idx,
+ void *data)
+{
+ struct zonefs_ioerr_data *err = data;
+ struct inode *inode = err->inode;
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ struct super_block *sb = inode->i_sb;
+ struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+ loff_t isize, data_size;
+
+ /*
+ * Check the zone condition: if the zone is not "bad" (offline or
+ * read-only), read errors are simply signaled to the IO issuer as long
+ * as there is no inconsistency between the inode size and the amount of
+ * data writen in the zone (data_size).
+ */
+ data_size = zonefs_check_zone_condition(inode, zone, true);
+ isize = i_size_read(inode);
+ if (zone->cond != BLK_ZONE_COND_OFFLINE &&
+ zone->cond != BLK_ZONE_COND_READONLY &&
+ !err->write && isize == data_size)
+ return 0;
+
+ /*
+ * At this point, we detected either a bad zone or an inconsistency
+ * between the inode size and the amount of data written in the zone.
+ * For the latter case, the cause may be a write IO error or an external
+ * action on the device. Two error patterns exist:
+ * 1) The inode size is lower than the amount of data in the zone:
+ * a write operation partially failed and data was writen at the end
+ * of the file. This can happen in the case of a large direct IO
+ * needing several BIOs and/or write requests to be processed.
+ * 2) The inode size is larger than the amount of data in the zone:
+ * this can happen with a deferred write error with the use of the
+ * device side write cache after getting successful write IO
+ * completions. Other possibilities are (a) an external corruption,
+ * e.g. an application reset the zone directly, or (b) the device
+ * has a serious problem (e.g. firmware bug).
+ *
+ * In all cases, warn about inode size inconsistency and handle the
+ * IO error according to the zone condition and to the mount options.
+ */
+ if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && isize != data_size)
+ zonefs_warn(sb, "inode %lu: invalid size %lld (should be %lld)\n",
+ inode->i_ino, isize, data_size);
+
+ /*
+ * First handle bad zones signaled by hardware. The mount options
+ * errors=zone-ro and errors=zone-offline result in changing the
+ * zone condition to read-only and offline respectively, as if the
+ * condition was signaled by the hardware.
+ */
+ if (zone->cond == BLK_ZONE_COND_OFFLINE ||
+ sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZOL) {
+ zonefs_warn(sb, "inode %lu: read/write access disabled\n",
+ inode->i_ino);
+ if (zone->cond != BLK_ZONE_COND_OFFLINE) {
+ zone->cond = BLK_ZONE_COND_OFFLINE;
+ data_size = zonefs_check_zone_condition(inode, zone,
+ false);
+ }
+ } else if (zone->cond == BLK_ZONE_COND_READONLY ||
+ sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZRO) {
+ zonefs_warn(sb, "inode %lu: write access disabled\n",
+ inode->i_ino);
+ if (zone->cond != BLK_ZONE_COND_READONLY) {
+ zone->cond = BLK_ZONE_COND_READONLY;
+ data_size = zonefs_check_zone_condition(inode, zone,
+ false);
+ }
+ }
+
+ /*
+ * If error=remount-ro was specified, any error result in remounting
+ * the volume as read-only.
+ */
+ if ((sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_RO) && !sb_rdonly(sb)) {
+ zonefs_warn(sb, "remounting filesystem read-only\n");
+ sb->s_flags |= SB_RDONLY;
+ }
+
+ /*
+ * Update block usage stats and the inode size to prevent access to
+ * invalid data.
+ */
+ zonefs_update_stats(inode, data_size);
+ i_size_write(inode, data_size);
+ zi->i_wpoffset = data_size;
+
+ return 0;
+}
+
+/*
+ * When an file IO error occurs, check the file zone to see if there is a change
+ * in the zone condition (e.g. offline or read-only). For a failed write to a
+ * sequential zone, the zone write pointer position must also be checked to
+ * eventually correct the file size and zonefs inode write pointer offset
+ * (which can be out of sync with the drive due to partial write failures).
+ */
+static void zonefs_io_error(struct inode *inode, bool write)
+{
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+ struct super_block *sb = inode->i_sb;
+ struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+ unsigned int noio_flag;
+ unsigned int nr_zones =
+ zi->i_max_size >> (sbi->s_zone_sectors_shift + SECTOR_SHIFT);
+ struct zonefs_ioerr_data err = {
+ .inode = inode,
+ .write = write,
+ };
+ int ret;
+
+ mutex_lock(&zi->i_truncate_mutex);
+
+ /*
+ * Memory allocations in blkdev_report_zones() can trigger a memory
+ * reclaim which may in turn cause a recursion into zonefs as well as
+ * struct request allocations for the same device. The former case may
+ * end up in a deadlock on the inode truncate mutex, while the latter
+ * may prevent IO forward progress. Executing the report zones under
+ * the GFP_NOIO context avoids both problems.
+ */
+ noio_flag = memalloc_noio_save();
+ ret = blkdev_report_zones(sb->s_bdev, zi->i_zsector, nr_zones,
+ zonefs_io_error_cb, &err);
+ if (ret != nr_zones)
+ zonefs_err(sb, "Get inode %lu zone information failed %d\n",
+ inode->i_ino, ret);
+ memalloc_noio_restore(noio_flag);
+
+ mutex_unlock(&zi->i_truncate_mutex);
+}
+
+static int zonefs_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;
+
+ /*
+ * Only sequential zone files can be truncated and truncation is allowed
+ * only down to a 0 size, which is equivalent to a zone reset, and to
+ * the maximum file size, which is equivalent to a zone finish.
+ */
+ if (zi->i_ztype != ZONEFS_ZTYPE_SEQ)
+ return -EPERM;
+
+ 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;
+
+ if (unlikely(IS_IMMUTABLE(inode)))
+ return -EPERM;
+
+ ret = setattr_prepare(dentry, iattr);
+ if (ret)
+ return ret;
+
+ /*
+ * Since files and directories cannot be created nor deleted, do not
+ * allow setting any write attributes on the sub-directories grouping
+ * files by zone type.
+ */
+ if ((iattr->ia_valid & ATTR_MODE) && S_ISDIR(inode->i_mode) &&
+ (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) {
+ ret = zonefs_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;
+
+ if (unlikely(IS_IMMUTABLE(inode)))
+ return -EPERM;
+
+ /*
+ * 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)
+ ret = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
+
+ if (ret)
+ zonefs_io_error(inode, true);
+
+ 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;
+
+ if (unlikely(IS_IMMUTABLE(inode)))
+ return VM_FAULT_SIGBUS;
+
+ /*
+ * Sanity check: only conventional zone files can have shared
+ * writeable mappings.
+ */
+ if (WARN_ON_ONCE(zi->i_ztype != ZONEFS_ZTYPE_CNV))
+ return VM_FAULT_NOPAGE;
+
+ 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 zones accept random writes, so their files can support
+ * shared writable mappings. For sequential zone files, only read
+ * mappings are possible since there are no guarantees for write
+ * ordering between msync() and page cache writeback.
+ */
+ 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 int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size,
+ int error, unsigned int flags)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+
+ if (error) {
+ zonefs_io_error(inode, true);
+ return error;
+ }
+
+ if (size && zi->i_ztype != ZONEFS_ZTYPE_CNV) {
+ /*
+ * Note that we may be seeing completions out of order,
+ * but that is not a problem since a write completed
+ * successfully necessarily means that all preceding writes
+ * were also successful. So we can safely increase the inode
+ * size to the write end location.
+ */
+ mutex_lock(&zi->i_truncate_mutex);
+ 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 0;
+}
+
+static const struct iomap_dio_ops zonefs_write_dio_ops = {
+ .end_io = zonefs_file_write_dio_end_io,
+};
+
+/*
+ * Handle direct writes. For sequential zone files, this is the only possible
+ * write path. For these files, check that the user is issuing writes
+ * sequentially from the end of the file. This code assumes that the block layer
+ * delivers write requests to the device in sequential order. This is always the
+ * case if a block IO scheduler implementing the ELEVATOR_F_ZBD_SEQ_WRITE
+ * elevator feature is being used (e.g. mq-deadline). The block layer always
+ * automatically select such an elevator for zoned block devices during the
+ * device initialization.
+ */
+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 super_block *sb = inode->i_sb;
+ size_t count;
+ ssize_t ret;
+
+ /*
+ * For async direct IOs to sequential zone files, ignore IOCB_NOWAIT
+ * as this can cause write reordering (e.g. the first aio gets EAGAIN
+ * on the inode lock but the second goes through but is now unaligned).
+ */
+ if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && !is_sync_kiocb(iocb)
+ && (iocb->ki_flags & IOCB_NOWAIT))
+ iocb->ki_flags &= ~IOCB_NOWAIT;
+
+ 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 inode_unlock;
+
+ iov_iter_truncate(from, zi->i_max_size - iocb->ki_pos);
+ count = iov_iter_count(from);
+
+ if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
+ ret = -EINVAL;
+ goto inode_unlock;
+ }
+
+ /* 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) {
+ mutex_unlock(&zi->i_truncate_mutex);
+ ret = -EINVAL;
+ goto inode_unlock;
+ }
+ mutex_unlock(&zi->i_truncate_mutex);
+
+ ret = iomap_dio_rw(iocb, from, &zonefs_iomap_ops,
+ &zonefs_write_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);
+ }
+
+inode_unlock:
+ 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);
+ ssize_t ret;
+
+ /*
+ * Direct IO writes are mandatory for sequential zone files so that the
+ * write IO issuing order is preserved.
+ */
+ if (zi->i_ztype != ZONEFS_ZTYPE_CNV)
+ 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 inode_unlock;
+
+ iov_iter_truncate(from, zi->i_max_size - iocb->ki_pos);
+
+ ret = iomap_file_buffered_write(iocb, from, &zonefs_iomap_ops);
+ if (ret > 0)
+ iocb->ki_pos += ret;
+ else if (ret == -EIO)
+ zonefs_io_error(inode, true);
+
+inode_unlock:
+ 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);
+
+ if (unlikely(IS_IMMUTABLE(inode)))
+ return -EPERM;
+
+ if (sb_rdonly(inode->i_sb))
+ return -EROFS;
+
+ /* Write operations beyond the zone size are not allowed */
+ 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 int zonefs_file_read_dio_end_io(struct kiocb *iocb, ssize_t size,
+ int error, unsigned int flags)
+{
+ if (error) {
+ zonefs_io_error(file_inode(iocb->ki_filp), false);
+ return error;
+ }
+
+ return 0;
+}
+
+static const struct iomap_dio_ops zonefs_read_dio_ops = {
+ .end_io = zonefs_file_read_dio_end_io,
+};
+
+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 super_block *sb = inode->i_sb;
+ loff_t isize;
+ ssize_t ret;
+
+ /* Offline zones cannot be read */
+ if (unlikely(IS_IMMUTABLE(inode) && !(inode->i_mode & 0777)))
+ return -EPERM;
+
+ 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);
+ }
+
+ /* Limit read operations to written data */
+ mutex_lock(&zi->i_truncate_mutex);
+ isize = i_size_read(inode);
+ if (iocb->ki_pos >= isize) {
+ mutex_unlock(&zi->i_truncate_mutex);
+ ret = 0;
+ goto inode_unlock;
+ }
+ iov_iter_truncate(to, isize - iocb->ki_pos);
+ mutex_unlock(&zi->i_truncate_mutex);
+
+ if (iocb->ki_flags & IOCB_DIRECT) {
+ size_t count = iov_iter_count(to);
+
+ if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
+ ret = -EINVAL;
+ goto inode_unlock;
+ }
+ file_accessed(iocb->ki_filp);
+ ret = iomap_dio_rw(iocb, to, &zonefs_iomap_ops,
+ &zonefs_read_dio_ops, is_sync_kiocb(iocb));
+ } else {
+ ret = generic_file_read_iter(iocb, to);
+ if (ret == -EIO)
+ zonefs_io_error(inode, false);
+ }
+
+inode_unlock:
+ inode_unlock_shared(inode);
+
+ return ret;
+}
+
+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;
+}
+
+enum {
+ Opt_errors_ro, Opt_errors_zro, Opt_errors_zol, Opt_errors_repair,
+ Opt_err,
+};
+
+static const match_table_t tokens = {
+ { Opt_errors_ro, "errors=remount-ro"},
+ { Opt_errors_zro, "errors=zone-ro"},
+ { Opt_errors_zol, "errors=zone-offline"},
+ { Opt_errors_repair, "errors=repair"},
+ { Opt_err, NULL}
+};
+
+static int zonefs_parse_options(struct super_block *sb, char *options)
+{
+ struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+ substring_t args[MAX_OPT_ARGS];
+ char *p;
+
+ if (!options)
+ return 0;
+
+ while ((p = strsep(&options, ",")) != NULL) {
+ int token;
+
+ if (!*p)
+ continue;
+
+ token = match_token(p, tokens, args);
+ switch (token) {
+ case Opt_errors_ro:
+ sbi->s_mount_opts &= ~ZONEFS_MNTOPT_ERRORS_MASK;
+ sbi->s_mount_opts |= ZONEFS_MNTOPT_ERRORS_RO;
+ break;
+ case Opt_errors_zro:
+ sbi->s_mount_opts &= ~ZONEFS_MNTOPT_ERRORS_MASK;
+ sbi->s_mount_opts |= ZONEFS_MNTOPT_ERRORS_ZRO;
+ break;
+ case Opt_errors_zol:
+ sbi->s_mount_opts &= ~ZONEFS_MNTOPT_ERRORS_MASK;
+ sbi->s_mount_opts |= ZONEFS_MNTOPT_ERRORS_ZOL;
+ break;
+ case Opt_errors_repair:
+ sbi->s_mount_opts &= ~ZONEFS_MNTOPT_ERRORS_MASK;
+ sbi->s_mount_opts |= ZONEFS_MNTOPT_ERRORS_REPAIR;
+ break;
+ default:
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+static int zonefs_show_options(struct seq_file *seq, struct dentry *root)
+{
+ struct zonefs_sb_info *sbi = ZONEFS_SB(root->d_sb);
+
+ if (sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_RO)
+ seq_puts(seq, ",errors=remount-ro");
+ if (sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZRO)
+ seq_puts(seq, ",errors=zone-ro");
+ if (sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZOL)
+ seq_puts(seq, ",errors=zone-offline");
+ if (sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_REPAIR)
+ seq_puts(seq, ",errors=repair");
+
+ return 0;
+}
+
+static int zonefs_remount(struct super_block *sb, int *flags, char *data)
+{
+ sync_filesystem(sb);
+
+ return zonefs_parse_options(sb, data);
+}
+
+static const struct super_operations zonefs_sops = {
+ .alloc_inode = zonefs_alloc_inode,
+ .free_inode = zonefs_free_inode,
+ .statfs = zonefs_statfs,
+ .remount_fs = zonefs_remount,
+ .show_options = zonefs_show_options,
+};
+
+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,
+ enum zonefs_ztype type)
+{
+ struct super_block *sb = parent->i_sb;
+
+ inode->i_ino = blkdev_nr_zones(sb->s_bdev->bd_disk) + type + 1;
+ 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,
+ enum zonefs_ztype type)
+{
+ struct super_block *sb = inode->i_sb;
+ struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
+ struct zonefs_inode_info *zi = ZONEFS_I(inode);
+
+ inode->i_ino = zone->start >> sbi->s_zone_sectors_shift;
+ inode->i_mode = S_IFREG | sbi->s_perm;
+
+ zi->i_ztype = type;
+ zi->i_zsector = zone->start;
+ zi->i_max_size = min_t(loff_t, MAX_LFS_FILESIZE,
+ zone->len << SECTOR_SHIFT);
+ zi->i_wpoffset = zonefs_check_zone_condition(inode, zone, true);
+
+ 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,
+ enum zonefs_ztype type)
+{
+ 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 dput;
+
+ inode->i_ctime = inode->i_mtime = inode->i_atime = dir->i_ctime;
+ if (zone)
+ zonefs_init_file_inode(inode, zone, type);
+ else
+ zonefs_init_dir_inode(dir, inode, type);
+ d_add(dentry, inode);
+ dir->i_size++;
+
+ return dentry;
+
+dput:
+ dput(dentry);
+
+ return NULL;
+}
+
+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;
+ const char *zgroup_name;
+ char *file_name;
+ struct dentry *dir;
+ unsigned int n = 0;
+ int ret = -ENOMEM;
+
+ /* If the group is empty, there is nothing to do */
+ if (!zd->nr_zones[type])
+ return 0;
+
+ file_name = kmalloc(ZONEFS_NAME_MAX, GFP_KERNEL);
+ if (!file_name)
+ return -ENOMEM;
+
+ if (type == ZONEFS_ZTYPE_CNV)
+ zgroup_name = "cnv";
+ else
+ zgroup_name = "seq";
+
+ dir = zonefs_create_inode(sb->s_root, zgroup_name, NULL, type);
+ if (!dir)
+ goto free;
+
+ /*
+ * 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. If one offline or read-only zone is
+ * found, assume that all zones aggregated have the same
+ * condition.
+ */
+ if (type == ZONEFS_ZTYPE_CNV &&
+ (sbi->s_features & ZONEFS_F_AGGRCNV)) {
+ for (; next < end; next++) {
+ if (zonefs_zone_type(next) != type)
+ break;
+ zone->len += next->len;
+ if (next->cond == BLK_ZONE_COND_READONLY &&
+ zone->cond != BLK_ZONE_COND_OFFLINE)
+ zone->cond = BLK_ZONE_COND_READONLY;
+ else if (next->cond == BLK_ZONE_COND_OFFLINE)
+ zone->cond = BLK_ZONE_COND_OFFLINE;
+ }
+ }
+
+ /*
+ * Use the file number within its group as file name.
+ */
+ snprintf(file_name, ZONEFS_NAME_MAX - 1, "%u", n);
+ if (!zonefs_create_inode(dir, file_name, zone, type))
+ goto free;
+
+ n++;
+ }
+
+ zonefs_info(sb, "Zone group \"%s\" has %u file%s\n",
+ zgroup_name, n, n > 1 ? "s" : "");
+
+ sbi->s_nr_files[type] = n;
+ ret = 0;
+
+free:
+ kfree(file_name);
+
+ return ret;
+}
+
+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 from the device */
+ 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.bi_opf = REQ_OP_READ;
+ bio_set_dev(&bio, sb->s_bdev);
+ bio_add_page(&bio, page, PAGE_SIZE, 0);
+
+ ret = submit_bio_wait(&bio);
+ if (ret)
+ goto free_page;
+
+ super = kmap(page);
+
+ ret = -EINVAL;
+ if (le32_to_cpu(super->s_magic) != ZONEFS_MAGIC)
+ goto unmap;
+
+ 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);
+ goto unmap;
+ }
+
+ 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 unmap;
+ }
+
+ 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 unmap;
+ }
+ }
+
+ 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 unmap;
+ }
+ }
+
+ 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 unmap;
+ }
+
+ uuid_copy(&sbi->s_uuid, (uuid_t *)super->s_uuid);
+ ret = 0;
+
+unmap:
+ kunmap(page);
+free_page:
+ __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 set to the device physical sector size to ensure
+ * that write operations on 512e devices (512B logical block and 4KB
+ * physical block) are always aligned to the device physical blocks,
+ * as mandated by the ZBC/ZAC specifications.
+ */
+ sb_set_blocksize(sb, bdev_physical_block_size(sb->s_bdev));
+ sbi->s_zone_sectors_shift = ilog2(bdev_zone_sectors(sb->s_bdev));
+ sbi->s_uid = GLOBAL_ROOT_UID;
+ sbi->s_gid = GLOBAL_ROOT_GID;
+ sbi->s_perm = 0640;
+ sbi->s_mount_opts = ZONEFS_MNTOPT_ERRORS_RO;
+
+ ret = zonefs_read_super(sb);
+ if (ret)
+ return ret;
+
+ ret = zonefs_parse_options(sb, data);
+ if (ret)
+ return ret;
+
+ memset(&zd, 0, sizeof(struct zonefs_zone_data));
+ zd.sb = sb;
+ ret = zonefs_get_zone_info(&zd);
+ if (ret)
+ goto cleanup;
+
+ 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 cleanup;
+
+ inode->i_ino = blkdev_nr_zones(sb->s_bdev->bd_disk);
+ 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 cleanup;
+
+ /* 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;
+ }
+
+cleanup:
+ 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);
+
+ if (sb->s_root)
+ d_genocide(sb->s_root);
+ kill_block_super(sb);
+ kfree(sbi);
+}
+
+/*
+ * 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..ad17fef7ce91
--- /dev/null
+++ b/fs/zonefs/zonefs.h
@@ -0,0 +1,189 @@
+/* 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 zone number 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_LABEL_LEN 64
+#define ZONEFS_UUID_SIZE 16
+#define ZONEFS_SUPER_SIZE 4096
+
+struct zonefs_super {
+
+ /* Magic number */
+ __le32 s_magic;
+
+ /* Checksum */
+ __le32 s_crc;
+
+ /* Volume label */
+ char s_label[ZONEFS_LABEL_LEN];
+
+ /* 128-bit uuid */
+ __u8 s_uuid[ZONEFS_UUID_SIZE];
+
+ /* Features */
+ __le64 s_features;
+
+ /* 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[3988];
+
+} __packed;
+
+/*
+ * Feature flags: specified in the s_features field of the on-disk super
+ * block 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 0.
+ */
+ ZONEFS_F_UID = 1ULL << 1,
+ /*
+ * Use super block specified GID for files instead of default 0.
+ */
+ 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)
+
+/*
+ * Mount options for zone write pointer error handling.
+ */
+#define ZONEFS_MNTOPT_ERRORS_RO (1 << 0) /* Make zone file readonly */
+#define ZONEFS_MNTOPT_ERRORS_ZRO (1 << 1) /* Make zone file offline */
+#define ZONEFS_MNTOPT_ERRORS_ZOL (1 << 2) /* Make zone file offline */
+#define ZONEFS_MNTOPT_ERRORS_REPAIR (1 << 3) /* Remount read-only */
+#define ZONEFS_MNTOPT_ERRORS_MASK \
+ (ZONEFS_MNTOPT_ERRORS_RO | ZONEFS_MNTOPT_ERRORS_ZRO | \
+ ZONEFS_MNTOPT_ERRORS_ZOL | ZONEFS_MNTOPT_ERRORS_REPAIR)
+
+/*
+ * In-memory Super block information.
+ */
+struct zonefs_sb_info {
+
+ unsigned long s_mount_opts;
+
+ 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;
+ unsigned int s_zone_sectors_shift;
+
+ 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) WARNING: " format, sb->s_id, ## args)
+
+#endif