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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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/pagemap.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 <linux/task_io_accounting_ops.h>
 
 #include "zonefs.h"
 
 #define CREATE_TRACE_POINTS
 #include "trace.h"
 
 /*
  * Manage the active zone count. Called with zi->i_truncate_mutex held.
  */
 static void zonefs_account_active(struct inode *inode)
 {
     struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
     struct zonefs_inode_info *zi = ZONEFS_I(inode);
 
     lockdep_assert_held(&zi->i_truncate_mutex);
 
     if (zi->i_ztype != ZONEFS_ZTYPE_SEQ)
         return;
 
     /*
      * If the zone is active, that is, if it is explicitly open or
      * partially written, check if it was already accounted as active.
      */
     if ((zi->i_flags & ZONEFS_ZONE_OPEN) ||
         (zi->i_wpoffset > 0 && zi->i_wpoffset < zi->i_max_size)) {
         if (!(zi->i_flags & ZONEFS_ZONE_ACTIVE)) {
             zi->i_flags |= ZONEFS_ZONE_ACTIVE;
             atomic_inc(&sbi->s_active_seq_files);
         }
         return;
     }
 
     /* The zone is not active. If it was, update the active count */
     if (zi->i_flags & ZONEFS_ZONE_ACTIVE) {
         zi->i_flags &= ~ZONEFS_ZONE_ACTIVE;
         atomic_dec(&sbi->s_active_seq_files);
     }
 }
 
 static inline int zonefs_zone_mgmt(struct inode *inode, enum req_op op)
 {
     struct zonefs_inode_info *zi = ZONEFS_I(inode);
     int ret;
 
     lockdep_assert_held(&zi->i_truncate_mutex);
 
     /*
      * With ZNS drives, closing an explicitly open zone that has not been
      * written will change the zone state to "closed", that is, the zone
      * will remain active. Since this can then cause failure of explicit
      * open operation on other zones if the drive active zone resources
      * are exceeded, make sure that the zone does not remain active by
      * resetting it.
      */
     if (op == REQ_OP_ZONE_CLOSE && !zi->i_wpoffset)
         op = REQ_OP_ZONE_RESET;
 
     trace_zonefs_zone_mgmt(inode, op);
     ret = blkdev_zone_mgmt(inode->i_sb->s_bdev, op, zi->i_zsector,
                    zi->i_zone_size >> SECTOR_SHIFT, GFP_NOFS);
     if (ret) {
         zonefs_err(inode->i_sb,
                "Zone management operation %s at %llu failed %d\n",
                blk_op_str(op), zi->i_zsector, ret);
         return ret;
     }
 
     return 0;
 }
 
 static inline void zonefs_i_size_write(struct inode *inode, loff_t isize)
 {
     struct zonefs_inode_info *zi = ZONEFS_I(inode);
 
     i_size_write(inode, isize);
     /*
      * A full zone is no longer open/active and does not need
      * explicit closing.
      */
     if (isize >= zi->i_max_size) {
         struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
 
         if (zi->i_flags & ZONEFS_ZONE_ACTIVE)
             atomic_dec(&sbi->s_active_seq_files);
         zi->i_flags &= ~(ZONEFS_ZONE_OPEN | ZONEFS_ZONE_ACTIVE);
     }
 }
 
 static int zonefs_read_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 blocks are always mapped below EOF. If reading past EOF,
      * act as if there is a hole up to the file maximum size.
      */
     mutex_lock(&zi->i_truncate_mutex);
     iomap->bdev = inode->i_sb->s_bdev;
     iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
     isize = i_size_read(inode);
     if (iomap->offset >= isize) {
         iomap->type = IOMAP_HOLE;
         iomap->addr = IOMAP_NULL_ADDR;
         iomap->length = length;
     } else {
         iomap->type = IOMAP_MAPPED;
         iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
         iomap->length = isize - iomap->offset;
     }
     mutex_unlock(&zi->i_truncate_mutex);
 
     trace_zonefs_iomap_begin(inode, iomap);
 
     return 0;
 }
 
 static const struct iomap_ops zonefs_read_iomap_ops = {
     .iomap_begin    = zonefs_read_iomap_begin,
 };
 
 static int zonefs_write_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 write 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_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);
     iomap->bdev = inode->i_sb->s_bdev;
     iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize);
     iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;
     isize = i_size_read(inode);
     if (iomap->offset >= isize) {
         iomap->type = IOMAP_UNWRITTEN;
         iomap->length = zi->i_max_size - iomap->offset;
     } else {
         iomap->type = IOMAP_MAPPED;
         iomap->length = isize - iomap->offset;
     }
     mutex_unlock(&zi->i_truncate_mutex);
 
     trace_zonefs_iomap_begin(inode, iomap);
 
     return 0;
 }
 
 static const struct iomap_ops zonefs_write_iomap_ops = {
     .iomap_begin    = zonefs_write_iomap_begin,
 };
 
 static int zonefs_read_folio(struct file *unused, struct folio *folio)
 {
     return iomap_read_folio(folio, &zonefs_read_iomap_ops);
 }
 
 static void zonefs_readahead(struct readahead_control *rac)
 {
     iomap_readahead(rac, &zonefs_read_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_write_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_write_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_write_map_blocks,
 };
 
 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 int zonefs_swap_activate(struct swap_info_struct *sis,
                 struct file *swap_file, sector_t *span)
 {
     struct inode *inode = file_inode(swap_file);
     struct zonefs_inode_info *zi = ZONEFS_I(inode);
 
     if (zi->i_ztype != ZONEFS_ZTYPE_CNV) {
         zonefs_err(inode->i_sb,
                "swap file: not a conventional zone file\n");
         return -EINVAL;
     }
 
     return iomap_swapfile_activate(sis, swap_file, span,
                        &zonefs_read_iomap_ops);
 }
 
 static const struct address_space_operations zonefs_file_aops = {
     .read_folio     = zonefs_read_folio,
     .readahead      = zonefs_readahead,
     .writepages     = zonefs_writepages,
     .dirty_folio        = filemap_dirty_folio,
     .release_folio      = iomap_release_folio,
     .invalidate_folio   = iomap_invalidate_folio,
     .migrate_folio      = filemap_migrate_folio,
     .is_partially_uptodate  = iomap_is_partially_uptodate,
     .error_remove_page  = generic_error_remove_page,
     .direct_IO      = noop_direct_IO,
     .swap_activate      = zonefs_swap_activate,
 };
 
 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,
                       bool mount)
 {
     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:
         /*
          * The write pointer of read-only zones is invalid. If such a
          * zone is found during mount, the file size cannot be retrieved
          * so we treat the zone as offline (mount == true case).
          * Otherwise, keep the file size as it was when last updated
          * so that the user can recover data. In both cases, writes are
          * always disabled for the zone.
          */
         if (warn)
             zonefs_warn(inode->i_sb, "inode %lu: read-only zone\n",
                     inode->i_ino);
         inode->i_flags |= S_IMMUTABLE;
         if (mount) {
             zone->cond = BLK_ZONE_COND_OFFLINE;
             inode->i_mode &= ~0777;
             zone->wp = zone->start;
             return 0;
         }
         inode->i_mode &= ~0222;
         return i_size_read(inode);
     case BLK_ZONE_COND_FULL:
         /* The write pointer of full zones is invalid. */
         return zi->i_max_size;
     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, false);
     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, 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, false);
         }
     }
 
     /*
      * If the filesystem is mounted with the explicit-open mount option, we
      * need to clear the ZONEFS_ZONE_OPEN flag if the zone transitioned to
      * the read-only or offline condition, to avoid attempting an explicit
      * close of the zone when the inode file is closed.
      */
     if ((sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN) &&
         (zone->cond == BLK_ZONE_COND_OFFLINE ||
          zone->cond == BLK_ZONE_COND_READONLY))
         zi->i_flags &= ~ZONEFS_ZONE_OPEN;
 
     /*
      * 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);
     zonefs_i_size_write(inode, data_size);
     zi->i_wpoffset = data_size;
     zonefs_account_active(inode);
 
     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_zone_size >> (sbi->s_zone_sectors_shift + SECTOR_SHIFT);
     struct zonefs_ioerr_data err = {
         .inode = inode,
         .write = write,
     };
     int ret;
 
     /*
      * 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);
 }
 
 static void zonefs_io_error(struct inode *inode, bool write)
 {
     struct zonefs_inode_info *zi = ZONEFS_I(inode);
 
     mutex_lock(&zi->i_truncate_mutex);
     __zonefs_io_error(inode, write);
     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_op 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 */
     filemap_invalidate_lock(inode->i_mapping);
 
     /* Serialize against zonefs_iomap_begin() */
     mutex_lock(&zi->i_truncate_mutex);
 
     old_isize = i_size_read(inode);
     if (isize == old_isize)
         goto unlock;
 
     ret = zonefs_zone_mgmt(inode, op);
     if (ret)
         goto unlock;
 
     /*
      * If the mount option ZONEFS_MNTOPT_EXPLICIT_OPEN is set,
      * take care of open zones.
      */
     if (zi->i_flags & ZONEFS_ZONE_OPEN) {
         /*
          * Truncating a zone to EMPTY or FULL is the equivalent of
          * closing the zone. For a truncation to 0, we need to
          * re-open the zone to ensure new writes can be processed.
          * For a truncation to the maximum file size, the zone is
          * closed and writes cannot be accepted anymore, so clear
          * the open flag.
          */
         if (!isize)
             ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_OPEN);
         else
             zi->i_flags &= ~ZONEFS_ZONE_OPEN;
     }
 
     zonefs_update_stats(inode, isize);
     truncate_setsize(inode, isize);
     zi->i_wpoffset = isize;
     zonefs_account_active(inode);
 
 unlock:
     mutex_unlock(&zi->i_truncate_mutex);
     filemap_invalidate_unlock(inode->i_mapping);
 
     return ret;
 }
 
 static int zonefs_inode_setattr(struct user_namespace *mnt_userns,
                 struct dentry *dentry, struct iattr *iattr)
 {
     struct inode *inode = d_inode(dentry);
     int ret;
 
     if (unlikely(IS_IMMUTABLE(inode)))
         return -EPERM;
 
     ret = setattr_prepare(&init_user_ns, 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(mnt_userns, 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(&init_user_ns, 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);
 
     if (ret)
         zonefs_io_error(inode, true);
 
     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 */
     filemap_invalidate_lock_shared(inode->i_mapping);
     ret = iomap_page_mkwrite(vmf, &zonefs_write_iomap_ops);
     filemap_invalidate_unlock_shared(inode->i_mapping);
 
     sb_end_pagefault(inode->i_sb);
     return ret;
 }
 
 static const struct vm_operations_struct zonefs_file_vm_ops = {
     .fault      = 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);
             zonefs_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,
 };
 
 static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
 {
     struct inode *inode = file_inode(iocb->ki_filp);
     struct zonefs_inode_info *zi = ZONEFS_I(inode);
     struct block_device *bdev = inode->i_sb->s_bdev;
     unsigned int max = bdev_max_zone_append_sectors(bdev);
     struct bio *bio;
     ssize_t size;
     int nr_pages;
     ssize_t ret;
 
     max = ALIGN_DOWN(max << SECTOR_SHIFT, inode->i_sb->s_blocksize);
     iov_iter_truncate(from, max);
 
     nr_pages = iov_iter_npages(from, BIO_MAX_VECS);
     if (!nr_pages)
         return 0;
 
     bio = bio_alloc(bdev, nr_pages,
             REQ_OP_ZONE_APPEND | REQ_SYNC | REQ_IDLE, GFP_NOFS);
     bio->bi_iter.bi_sector = zi->i_zsector;
     bio->bi_ioprio = iocb->ki_ioprio;
     if (iocb_is_dsync(iocb))
         bio->bi_opf |= REQ_FUA;
 
     ret = bio_iov_iter_get_pages(bio, from);
     if (unlikely(ret))
         goto out_release;
 
     size = bio->bi_iter.bi_size;
     task_io_account_write(size);
 
     if (iocb->ki_flags & IOCB_HIPRI)
         bio_set_polled(bio, iocb);
 
     ret = submit_bio_wait(bio);
 
     zonefs_file_write_dio_end_io(iocb, size, ret, 0);
     trace_zonefs_file_dio_append(inode, size, ret);
 
 out_release:
     bio_release_pages(bio, false);
     bio_put(bio);
 
     if (ret >= 0) {
         iocb->ki_pos += size;
         return size;
     }
 
     return ret;
 }
 
 /*
  * Do not exceed the LFS limits nor the file zone size. If pos is under the
  * limit it becomes a short access. If it exceeds the limit, return -EFBIG.
  */
 static loff_t zonefs_write_check_limits(struct file *file, loff_t pos,
                     loff_t count)
 {
     struct inode *inode = file_inode(file);
     struct zonefs_inode_info *zi = ZONEFS_I(inode);
     loff_t limit = rlimit(RLIMIT_FSIZE);
     loff_t max_size = zi->i_max_size;
 
     if (limit != RLIM_INFINITY) {
         if (pos >= limit) {
             send_sig(SIGXFSZ, current, 0);
             return -EFBIG;
         }
         count = min(count, limit - pos);
     }
 
     if (!(file->f_flags & O_LARGEFILE))
         max_size = min_t(loff_t, MAX_NON_LFS, max_size);
 
     if (unlikely(pos >= max_size))
         return -EFBIG;
 
     return min(count, max_size - pos);
 }
 
 static ssize_t zonefs_write_checks(struct kiocb *iocb, struct iov_iter *from)
 {
     struct file *file = iocb->ki_filp;
     struct inode *inode = file_inode(file);
     struct zonefs_inode_info *zi = ZONEFS_I(inode);
     loff_t count;
 
     if (IS_SWAPFILE(inode))
         return -ETXTBSY;
 
     if (!iov_iter_count(from))
         return 0;
 
     if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
         return -EINVAL;
 
     if (iocb->ki_flags & IOCB_APPEND) {
         if (zi->i_ztype != ZONEFS_ZTYPE_SEQ)
             return -EINVAL;
         mutex_lock(&zi->i_truncate_mutex);
         iocb->ki_pos = zi->i_wpoffset;
         mutex_unlock(&zi->i_truncate_mutex);
     }
 
     count = zonefs_write_check_limits(file, iocb->ki_pos,
                       iov_iter_count(from));
     if (count < 0)
         return count;
 
     iov_iter_truncate(from, count);
     return iov_iter_count(from);
 }
 
 /*
  * 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;
     bool sync = is_sync_kiocb(iocb);
     bool append = false;
     ssize_t ret, count;
 
     /*
      * For async direct IOs to sequential zone files, refuse 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 && !sync &&
         (iocb->ki_flags & IOCB_NOWAIT))
         return -EOPNOTSUPP;
 
     if (iocb->ki_flags & IOCB_NOWAIT) {
         if (!inode_trylock(inode))
             return -EAGAIN;
     } else {
         inode_lock(inode);
     }
 
     count = zonefs_write_checks(iocb, from);
     if (count <= 0) {
         ret = count;
         goto inode_unlock;
     }
 
     if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
         ret = -EINVAL;
         goto inode_unlock;
     }
 
     /* Enforce sequential writes (append only) in sequential zones */
     if (zi->i_ztype == ZONEFS_ZTYPE_SEQ) {
         mutex_lock(&zi->i_truncate_mutex);
         if (iocb->ki_pos != zi->i_wpoffset) {
             mutex_unlock(&zi->i_truncate_mutex);
             ret = -EINVAL;
             goto inode_unlock;
         }
         mutex_unlock(&zi->i_truncate_mutex);
         append = sync;
     }
 
     if (append)
         ret = zonefs_file_dio_append(iocb, from);
     else
         ret = iomap_dio_rw(iocb, from, &zonefs_write_iomap_ops,
                    &zonefs_write_dio_ops, 0, NULL, 0);
     if (zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
         (ret > 0 || ret == -EIOCBQUEUED)) {
         if (ret > 0)
             count = ret;
 
         /*
          * Update the zone write pointer offset assuming the write
          * operation succeeded. If it did not, the error recovery path
          * will correct it. Also do active seq file accounting.
          */
         mutex_lock(&zi->i_truncate_mutex);
         zi->i_wpoffset += count;
         zonefs_account_active(inode);
         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 = zonefs_write_checks(iocb, from);
     if (ret <= 0)
         goto inode_unlock;
 
     ret = iomap_file_buffered_write(iocb, from, &zonefs_write_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) {
         ssize_t ret = zonefs_file_dio_write(iocb, from);
         if (ret != -ENOTBLK)
             return ret;
     }
 
     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_read_iomap_ops,
                    &zonefs_read_dio_ops, 0, NULL, 0);
     } else {
         ret = generic_file_read_iter(iocb, to);
         if (ret == -EIO)
             zonefs_io_error(inode, false);
     }
 
 inode_unlock:
     inode_unlock_shared(inode);
 
     return ret;
 }
 
 /*
  * Write open accounting is done only for sequential files.
  */
 static inline bool zonefs_seq_file_need_wro(struct inode *inode,
                         struct file *file)
 {
     struct zonefs_inode_info *zi = ZONEFS_I(inode);
 
     if (zi->i_ztype != ZONEFS_ZTYPE_SEQ)
         return false;
 
     if (!(file->f_mode & FMODE_WRITE))
         return false;
 
     return true;
 }
 
 static int zonefs_seq_file_write_open(struct inode *inode)
 {
     struct zonefs_inode_info *zi = ZONEFS_I(inode);
     int ret = 0;
 
     mutex_lock(&zi->i_truncate_mutex);
 
     if (!zi->i_wr_refcnt) {
         struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
         unsigned int wro = atomic_inc_return(&sbi->s_wro_seq_files);
 
         if (sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN) {
 
             if (sbi->s_max_wro_seq_files
                 && wro > sbi->s_max_wro_seq_files) {
                 atomic_dec(&sbi->s_wro_seq_files);
                 ret = -EBUSY;
                 goto unlock;
             }
 
             if (i_size_read(inode) < zi->i_max_size) {
                 ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_OPEN);
                 if (ret) {
                     atomic_dec(&sbi->s_wro_seq_files);
                     goto unlock;
                 }
                 zi->i_flags |= ZONEFS_ZONE_OPEN;
                 zonefs_account_active(inode);
             }
         }
     }
 
     zi->i_wr_refcnt++;
 
 unlock:
     mutex_unlock(&zi->i_truncate_mutex);
 
     return ret;
 }
 
 static int zonefs_file_open(struct inode *inode, struct file *file)
 {
     int ret;
 
     ret = generic_file_open(inode, file);
     if (ret)
         return ret;
 
     if (zonefs_seq_file_need_wro(inode, file))
         return zonefs_seq_file_write_open(inode);
 
     return 0;
 }
 
 static void zonefs_seq_file_write_close(struct inode *inode)
 {
     struct zonefs_inode_info *zi = ZONEFS_I(inode);
     struct super_block *sb = inode->i_sb;
     struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
     int ret = 0;
 
     mutex_lock(&zi->i_truncate_mutex);
 
     zi->i_wr_refcnt--;
     if (zi->i_wr_refcnt)
         goto unlock;
 
     /*
      * The file zone may not be open anymore (e.g. the file was truncated to
      * its maximum size or it was fully written). For this case, we only
      * need to decrement the write open count.
      */
     if (zi->i_flags & ZONEFS_ZONE_OPEN) {
         ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_CLOSE);
         if (ret) {
             __zonefs_io_error(inode, false);
             /*
              * Leaving zones explicitly open may lead to a state
              * where most zones cannot be written (zone resources
              * exhausted). So take preventive action by remounting
              * read-only.
              */
             if (zi->i_flags & ZONEFS_ZONE_OPEN &&
                 !(sb->s_flags & SB_RDONLY)) {
                 zonefs_warn(sb,
                     "closing zone at %llu failed %d\n",
                     zi->i_zsector, ret);
                 zonefs_warn(sb,
                     "remounting filesystem read-only\n");
                 sb->s_flags |= SB_RDONLY;
             }
             goto unlock;
         }
 
         zi->i_flags &= ~ZONEFS_ZONE_OPEN;
         zonefs_account_active(inode);
     }
 
     atomic_dec(&sbi->s_wro_seq_files);
 
 unlock:
     mutex_unlock(&zi->i_truncate_mutex);
 }
 
 static int zonefs_file_release(struct inode *inode, struct file *file)
 {
     /*
      * If we explicitly open a zone we must close it again as well, but the
      * zone management operation can fail (either due to an IO error or as
      * the zone has gone offline or read-only). Make sure we don't fail the
      * close(2) for user-space.
      */
     if (zonefs_seq_file_need_wro(inode, file))
         zonefs_seq_file_write_close(inode);
 
     return 0;
 }
 
 static const struct file_operations zonefs_file_operations = {
     .open       = zonefs_file_open,
     .release    = zonefs_file_release,
     .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     = iocb_bio_iopoll,
 };
 
 static struct kmem_cache *zonefs_inode_cachep;
 
 static struct inode *zonefs_alloc_inode(struct super_block *sb)
 {
     struct zonefs_inode_info *zi;
 
     zi = alloc_inode_sb(sb, zonefs_inode_cachep, GFP_KERNEL);
     if (!zi)
         return NULL;
 
     inode_init_once(&zi->i_vnode);
     mutex_init(&zi->i_truncate_mutex);
     zi->i_wr_refcnt = 0;
     zi->i_flags = 0;
 
     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;
 
     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);
 
     buf->f_fsid = uuid_to_fsid(sbi->s_uuid.b);
 
     return 0;
 }
 
 enum {
     Opt_errors_ro, Opt_errors_zro, Opt_errors_zol, Opt_errors_repair,
     Opt_explicit_open, 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_explicit_open,    "explicit-open" },
     { 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;
         case Opt_explicit_open:
             sbi->s_mount_opts |= ZONEFS_MNTOPT_EXPLICIT_OPEN;
             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 = bdev_nr_zones(sb->s_bdev) + type + 1;
     inode_init_owner(&init_user_ns, 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 int 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);
     int ret = 0;
 
     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_zone_size = zone->len << SECTOR_SHIFT;
 
     zi->i_max_size = min_t(loff_t, MAX_LFS_FILESIZE,
                    zone->capacity << SECTOR_SHIFT);
     zi->i_wpoffset = zonefs_check_zone_condition(inode, zone, true, true);
 
     inode->i_uid = sbi->s_uid;
     inode->i_gid = sbi->s_gid;
     inode->i_size = zi->i_wpoffset;
     inode->i_blocks = zi->i_max_size >> SECTOR_SHIFT;
 
     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;
 
     mutex_lock(&zi->i_truncate_mutex);
 
     /*
      * For sequential zones, make sure that any open zone is closed first
      * to ensure that the initial number of open zones is 0, in sync with
      * the open zone accounting done when the mount option
      * ZONEFS_MNTOPT_EXPLICIT_OPEN is used.
      */
     if (type == ZONEFS_ZTYPE_SEQ &&
         (zone->cond == BLK_ZONE_COND_IMP_OPEN ||
          zone->cond == BLK_ZONE_COND_EXP_OPEN)) {
         ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_CLOSE);
         if (ret)
             goto unlock;
     }
 
     zonefs_account_active(inode);
 
 unlock:
     mutex_unlock(&zi->i_truncate_mutex);
 
     return ret;
 }
 
 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;
     int ret;
 
     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) {
         ret = zonefs_init_file_inode(inode, zone, type);
         if (ret) {
             iput(inode);
             goto dput;
         }
     } 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;
 
     /* 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) {
         ret = -ENOMEM;
         goto free;
     }
 
     /*
      * The first zone contains the super block: skip it.
      */
     end = zd->zones + bdev_nr_zones(sb->s_bdev);
     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;
                 zone->capacity += next->capacity;
                 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;
             }
             if (zone->capacity != zone->len) {
                 zonefs_err(sb, "Invalid conventional zone capacity\n");
                 ret = -EINVAL;
                 goto free;
             }
         }
 
         /*
          * 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)) {
             ret = -ENOMEM;
             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(bdev_nr_zones(bdev), 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 != bdev_nr_zones(bdev)) {
         zonefs_err(zd->sb, "Invalid zone report (%d/%u zones)\n",
                ret, bdev_nr_zones(bdev));
         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, sb->s_bdev, &bio_vec, 1, REQ_OP_READ);
     bio.bi_iter.bi_sector = 0;
     bio_add_page(&bio, page, PAGE_SIZE, 0);
 
     ret = submit_bio_wait(&bio);
     if (ret)
         goto free_page;
 
     super = page_address(page);
 
     ret = -EINVAL;
     if (le32_to_cpu(super->s_magic) != ZONEFS_MAGIC)
         goto free_page;
 
     stored_crc = le32_to_cpu(super->s_crc);
     super->s_crc = 0;
     crc = crc32(~0U, (unsigned char *)super, sizeof(struct zonefs_super));
     if (crc != stored_crc) {
         zonefs_err(sb, "Invalid checksum (Expected 0x%08x, got 0x%08x)",
                crc, stored_crc);
         goto free_page;
     }
 
     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 free_page;
     }
 
     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 free_page;
         }
     }
 
     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 free_page;
         }
     }
 
     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 free_page;
     }
 
     import_uuid(&sbi->s_uuid, super->s_uuid);
     ret = 0;
 
 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 zone write granularity to ensure
      * that write operations are always aligned according to the device
      * interface constraints.
      */
     sb_set_blocksize(sb, bdev_zone_write_granularity(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;
 
     atomic_set(&sbi->s_wro_seq_files, 0);
     sbi->s_max_wro_seq_files = bdev_max_open_zones(sb->s_bdev);
     atomic_set(&sbi->s_active_seq_files, 0);
     sbi->s_max_active_seq_files = bdev_max_active_zones(sb->s_bdev);
 
     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;
 
     ret = zonefs_sysfs_register(sb);
     if (ret)
         goto cleanup;
 
     zonefs_info(sb, "Mounting %u zones", bdev_nr_zones(sb->s_bdev));
 
     if (!sbi->s_max_wro_seq_files &&
         !sbi->s_max_active_seq_files &&
         sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN) {
         zonefs_info(sb,
             "No open and active zone limits. Ignoring explicit_open mount option\n");
         sbi->s_mount_opts &= ~ZONEFS_MNTOPT_EXPLICIT_OPEN;
     }
 
     /* Create root directory inode */
     ret = -ENOMEM;
     inode = new_inode(sb);
     if (!inode)
         goto cleanup;
 
     inode->i_ino = bdev_nr_zones(sb->s_bdev);
     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);
 
     zonefs_sysfs_unregister(sb);
     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)
         goto destroy_inodecache;
 
     ret = zonefs_sysfs_init();
     if (ret)
         goto unregister_fs;
 
     return 0;
 
 unregister_fs:
     unregister_filesystem(&zonefs_type);
 destroy_inodecache:
     zonefs_destroy_inodecache();
 
     return ret;
 }
 
 static void __exit zonefs_exit(void)
 {
     zonefs_sysfs_exit();
     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_ALIAS_FS("zonefs");
 module_init(zonefs_init);
 module_exit(zonefs_exit);

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