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linux-stable/fs/zonefs/super.c
Damien Le Moal 6d5eae9a95 zonefs: Improve error handling 
commit 14db5f64a9 upstream.

Write error handling is racy and can sometime lead to the error recovery
path wrongly changing the inode size of a sequential zone file to an
incorrect value  which results in garbage data being readable at the end
of a file. There are 2 problems:

1) zonefs_file_dio_write() updates a zone file write pointer offset
   after issuing a direct IO with iomap_dio_rw(). This update is done
   only if the IO succeed for synchronous direct writes. However, for
   asynchronous direct writes, the update is done without waiting for
   the IO completion so that the next asynchronous IO can be
   immediately issued. However, if an asynchronous IO completes with a
   failure right before the i_truncate_mutex lock protecting the update,
   the update may change the value of the inode write pointer offset
   that was corrected by the error path (zonefs_io_error() function).

2) zonefs_io_error() is called when a read or write error occurs. This
   function executes a report zone operation using the callback function
   zonefs_io_error_cb(), which does all the error recovery handling
   based on the current zone condition, write pointer position and
   according to the mount options being used. However, depending on the
   zoned device being used, a report zone callback may be executed in a
   context that is different from the context of __zonefs_io_error(). As
   a result, zonefs_io_error_cb() may be executed without the inode
   truncate mutex lock held, which can lead to invalid error processing.

Fix both problems as follows:
- Problem 1: Perform the inode write pointer offset update before a
  direct write is issued with iomap_dio_rw(). This is safe to do as
  partial direct writes are not supported (IOMAP_DIO_PARTIAL is not
  set) and any failed IO will trigger the execution of zonefs_io_error()
  which will correct the inode write pointer offset to reflect the
  current state of the one on the device.
- Problem 2: Change zonefs_io_error_cb() into zonefs_handle_io_error()
  and call this function directly from __zonefs_io_error() after
  obtaining the zone information using blkdev_report_zones() with a
  simple callback function that copies to a local stack variable the
  struct blk_zone obtained from the device. This ensures that error
  handling is performed holding the inode truncate mutex.
  This change also simplifies error handling for conventional zone files
  by bypassing the execution of report zones entirely. This is safe to
  do because the condition of conventional zones cannot be read-only or
  offline and conventional zone files are always fully mapped with a
  constant file size.

Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Fixes: 8dcc1a9d90 ("fs: New zonefs file system")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:25:13 +01:00

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// 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"
/*
* Get the name of a zone group directory.
*/
static const char *zonefs_zgroup_name(enum zonefs_ztype ztype)
{
switch (ztype) {
case ZONEFS_ZTYPE_CNV:
return "cnv";
case ZONEFS_ZTYPE_SEQ:
return "seq";
default:
WARN_ON_ONCE(1);
return "???";
}
}
/*
* Manage the active zone count.
*/
static void zonefs_account_active(struct super_block *sb,
struct zonefs_zone *z)
{
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
if (zonefs_zone_is_cnv(z))
return;
/*
* For zones that transitioned to the offline or readonly condition,
* we only need to clear the active state.
*/
if (z->z_flags & (ZONEFS_ZONE_OFFLINE | ZONEFS_ZONE_READONLY))
goto out;
/*
* If the zone is active, that is, if it is explicitly open or
* partially written, check if it was already accounted as active.
*/
if ((z->z_flags & ZONEFS_ZONE_OPEN) ||
(z->z_wpoffset > 0 && z->z_wpoffset < z->z_capacity)) {
if (!(z->z_flags & ZONEFS_ZONE_ACTIVE)) {
z->z_flags |= ZONEFS_ZONE_ACTIVE;
atomic_inc(&sbi->s_active_seq_files);
}
return;
}
out:
/* The zone is not active. If it was, update the active count */
if (z->z_flags & ZONEFS_ZONE_ACTIVE) {
z->z_flags &= ~ZONEFS_ZONE_ACTIVE;
atomic_dec(&sbi->s_active_seq_files);
}
}
/*
* Manage the active zone count. Called with zi->i_truncate_mutex held.
*/
void zonefs_inode_account_active(struct inode *inode)
{
lockdep_assert_held(&ZONEFS_I(inode)->i_truncate_mutex);
return zonefs_account_active(inode->i_sb, zonefs_inode_zone(inode));
}
/*
* Execute a zone management operation.
*/
static int zonefs_zone_mgmt(struct super_block *sb,
struct zonefs_zone *z, enum req_op op)
{
int ret;
/*
* 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 && !z->z_wpoffset)
op = REQ_OP_ZONE_RESET;
trace_zonefs_zone_mgmt(sb, z, op);
ret = blkdev_zone_mgmt(sb->s_bdev, op, z->z_sector,
z->z_size >> SECTOR_SHIFT, GFP_NOFS);
if (ret) {
zonefs_err(sb,
"Zone management operation %s at %llu failed %d\n",
blk_op_str(op), z->z_sector, ret);
return ret;
}
return 0;
}
int zonefs_inode_zone_mgmt(struct inode *inode, enum req_op op)
{
lockdep_assert_held(&ZONEFS_I(inode)->i_truncate_mutex);
return zonefs_zone_mgmt(inode->i_sb, zonefs_inode_zone(inode), op);
}
void zonefs_i_size_write(struct inode *inode, loff_t isize)
{
struct zonefs_zone *z = zonefs_inode_zone(inode);
i_size_write(inode, isize);
/*
* A full zone is no longer open/active and does not need
* explicit closing.
*/
if (isize >= z->z_capacity) {
struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
if (z->z_flags & ZONEFS_ZONE_ACTIVE)
atomic_dec(&sbi->s_active_seq_files);
z->z_flags &= ~(ZONEFS_ZONE_OPEN | ZONEFS_ZONE_ACTIVE);
}
}
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. Return the amount of written (and still readable)
* data in the zone.
*/
static loff_t zonefs_check_zone_condition(struct super_block *sb,
struct zonefs_zone *z,
struct blk_zone *zone)
{
switch (zone->cond) {
case BLK_ZONE_COND_OFFLINE:
zonefs_warn(sb, "Zone %llu: offline zone\n",
z->z_sector);
z->z_flags |= ZONEFS_ZONE_OFFLINE;
return 0;
case BLK_ZONE_COND_READONLY:
/*
* The write pointer of read-only zones is invalid, so we cannot
* determine the zone wpoffset (inode size). We thus keep the
* zone wpoffset as is, which leads to an empty file
* (wpoffset == 0) on mount. For a runtime error, this keeps
* the inode size as it was when last updated so that the user
* can recover data.
*/
zonefs_warn(sb, "Zone %llu: read-only zone\n",
z->z_sector);
z->z_flags |= ZONEFS_ZONE_READONLY;
if (zonefs_zone_is_cnv(z))
return z->z_capacity;
return z->z_wpoffset;
case BLK_ZONE_COND_FULL:
/* The write pointer of full zones is invalid. */
return z->z_capacity;
default:
if (zonefs_zone_is_cnv(z))
return z->z_capacity;
return (zone->wp - zone->start) << SECTOR_SHIFT;
}
}
/*
* Check a zone condition and adjust its inode access permissions for
* offline and readonly zones.
*/
static void zonefs_inode_update_mode(struct inode *inode)
{
struct zonefs_zone *z = zonefs_inode_zone(inode);
if (z->z_flags & ZONEFS_ZONE_OFFLINE) {
/* Offline zones cannot be read nor written */
inode->i_flags |= S_IMMUTABLE;
inode->i_mode &= ~0777;
} else if (z->z_flags & ZONEFS_ZONE_READONLY) {
/* Readonly zones cannot be written */
inode->i_flags |= S_IMMUTABLE;
if (z->z_flags & ZONEFS_ZONE_INIT_MODE)
inode->i_mode &= ~0777;
else
inode->i_mode &= ~0222;
}
z->z_flags &= ~ZONEFS_ZONE_INIT_MODE;
z->z_mode = inode->i_mode;
}
static int zonefs_io_error_cb(struct blk_zone *zone, unsigned int idx,
void *data)
{
struct blk_zone *z = data;
*z = *zone;
return 0;
}
static void zonefs_handle_io_error(struct inode *inode, struct blk_zone *zone,
bool write)
{
struct zonefs_zone *z = zonefs_inode_zone(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(sb, z, zone);
isize = i_size_read(inode);
if (!(z->z_flags & (ZONEFS_ZONE_READONLY | ZONEFS_ZONE_OFFLINE)) &&
!write && isize == data_size)
return;
/*
* 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 (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 ((z->z_flags & ZONEFS_ZONE_OFFLINE) ||
(sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZOL)) {
zonefs_warn(sb, "inode %lu: read/write access disabled\n",
inode->i_ino);
if (!(z->z_flags & ZONEFS_ZONE_OFFLINE))
z->z_flags |= ZONEFS_ZONE_OFFLINE;
zonefs_inode_update_mode(inode);
data_size = 0;
} else if ((z->z_flags & ZONEFS_ZONE_READONLY) ||
(sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZRO)) {
zonefs_warn(sb, "inode %lu: write access disabled\n",
inode->i_ino);
if (!(z->z_flags & ZONEFS_ZONE_READONLY))
z->z_flags |= ZONEFS_ZONE_READONLY;
zonefs_inode_update_mode(inode);
data_size = isize;
} else if (sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_RO &&
data_size > isize) {
/* Do not expose garbage data */
data_size = isize;
}
/*
* 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) &&
(z->z_flags & (ZONEFS_ZONE_READONLY | ZONEFS_ZONE_OFFLINE)))
z->z_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);
z->z_wpoffset = data_size;
zonefs_inode_account_active(inode);
}
/*
* 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).
*/
void __zonefs_io_error(struct inode *inode, bool write)
{
struct zonefs_zone *z = zonefs_inode_zone(inode);
struct super_block *sb = inode->i_sb;
unsigned int noio_flag;
struct blk_zone zone;
int ret;
/*
* Conventional zone have no write pointer and cannot become read-only
* or offline. So simply fake a report for a single or aggregated zone
* and let zonefs_handle_io_error() correct the zone inode information
* according to the mount options.
*/
if (!zonefs_zone_is_seq(z)) {
zone.start = z->z_sector;
zone.len = z->z_size >> SECTOR_SHIFT;
zone.wp = zone.start + zone.len;
zone.type = BLK_ZONE_TYPE_CONVENTIONAL;
zone.cond = BLK_ZONE_COND_NOT_WP;
zone.capacity = zone.len;
goto handle_io_error;
}
/*
* 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, z->z_sector, 1,
zonefs_io_error_cb, &zone);
memalloc_noio_restore(noio_flag);
if (ret != 1) {
zonefs_err(sb, "Get inode %lu zone information failed %d\n",
inode->i_ino, ret);
zonefs_warn(sb, "remounting filesystem read-only\n");
sb->s_flags |= SB_RDONLY;
return;
}
handle_io_error:
zonefs_handle_io_error(inode, &zone, write);
}
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;
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_zgroup[t].g_nr_zones)
buf->f_files += sbi->s_zgroup[t].g_nr_zones + 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 int zonefs_inode_setattr(struct mnt_idmap *idmap,
struct dentry *dentry, struct iattr *iattr)
{
struct inode *inode = d_inode(dentry);
int ret;
if (unlikely(IS_IMMUTABLE(inode)))
return -EPERM;
ret = setattr_prepare(&nop_mnt_idmap, 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(&nop_mnt_idmap, 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(&nop_mnt_idmap, inode, iattr);
if (S_ISREG(inode->i_mode)) {
struct zonefs_zone *z = zonefs_inode_zone(inode);
z->z_mode = inode->i_mode;
z->z_uid = inode->i_uid;
z->z_gid = inode->i_gid;
}
return 0;
}
static const struct inode_operations zonefs_file_inode_operations = {
.setattr = zonefs_inode_setattr,
};
static long zonefs_fname_to_fno(const struct qstr *fname)
{
const char *name = fname->name;
unsigned int len = fname->len;
long fno = 0, shift = 1;
const char *rname;
char c = *name;
unsigned int i;
/*
* File names are always a base-10 number string without any
* leading 0s.
*/
if (!isdigit(c))
return -ENOENT;
if (len > 1 && c == '0')
return -ENOENT;
if (len == 1)
return c - '0';
for (i = 0, rname = name + len - 1; i < len; i++, rname--) {
c = *rname;
if (!isdigit(c))
return -ENOENT;
fno += (c - '0') * shift;
shift *= 10;
}
return fno;
}
static struct inode *zonefs_get_file_inode(struct inode *dir,
struct dentry *dentry)
{
struct zonefs_zone_group *zgroup = dir->i_private;
struct super_block *sb = dir->i_sb;
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
struct zonefs_zone *z;
struct inode *inode;
ino_t ino;
long fno;
/* Get the file number from the file name */
fno = zonefs_fname_to_fno(&dentry->d_name);
if (fno < 0)
return ERR_PTR(fno);
if (!zgroup->g_nr_zones || fno >= zgroup->g_nr_zones)
return ERR_PTR(-ENOENT);
z = &zgroup->g_zones[fno];
ino = z->z_sector >> sbi->s_zone_sectors_shift;
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
if (!(inode->i_state & I_NEW)) {
WARN_ON_ONCE(inode->i_private != z);
return inode;
}
inode->i_ino = ino;
inode->i_mode = z->z_mode;
inode->i_mtime = inode->i_atime = inode_set_ctime_to_ts(inode,
inode_get_ctime(dir));
inode->i_uid = z->z_uid;
inode->i_gid = z->z_gid;
inode->i_size = z->z_wpoffset;
inode->i_blocks = z->z_capacity >> SECTOR_SHIFT;
inode->i_private = z;
inode->i_op = &zonefs_file_inode_operations;
inode->i_fop = &zonefs_file_operations;
inode->i_mapping->a_ops = &zonefs_file_aops;
/* Update the inode access rights depending on the zone condition */
zonefs_inode_update_mode(inode);
unlock_new_inode(inode);
return inode;
}
static struct inode *zonefs_get_zgroup_inode(struct super_block *sb,
enum zonefs_ztype ztype)
{
struct inode *root = d_inode(sb->s_root);
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
struct inode *inode;
ino_t ino = bdev_nr_zones(sb->s_bdev) + ztype + 1;
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
if (!(inode->i_state & I_NEW))
return inode;
inode->i_ino = ino;
inode_init_owner(&nop_mnt_idmap, inode, root, S_IFDIR | 0555);
inode->i_size = sbi->s_zgroup[ztype].g_nr_zones;
inode->i_mtime = inode->i_atime = inode_set_ctime_to_ts(inode,
inode_get_ctime(root));
inode->i_private = &sbi->s_zgroup[ztype];
set_nlink(inode, 2);
inode->i_op = &zonefs_dir_inode_operations;
inode->i_fop = &zonefs_dir_operations;
unlock_new_inode(inode);
return inode;
}
static struct inode *zonefs_get_dir_inode(struct inode *dir,
struct dentry *dentry)
{
struct super_block *sb = dir->i_sb;
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
const char *name = dentry->d_name.name;
enum zonefs_ztype ztype;
/*
* We only need to check for the "seq" directory and
* the "cnv" directory if we have conventional zones.
*/
if (dentry->d_name.len != 3)
return ERR_PTR(-ENOENT);
for (ztype = 0; ztype < ZONEFS_ZTYPE_MAX; ztype++) {
if (sbi->s_zgroup[ztype].g_nr_zones &&
memcmp(name, zonefs_zgroup_name(ztype), 3) == 0)
break;
}
if (ztype == ZONEFS_ZTYPE_MAX)
return ERR_PTR(-ENOENT);
return zonefs_get_zgroup_inode(sb, ztype);
}
static struct dentry *zonefs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
struct inode *inode;
if (dentry->d_name.len > ZONEFS_NAME_MAX)
return ERR_PTR(-ENAMETOOLONG);
if (dir == d_inode(dir->i_sb->s_root))
inode = zonefs_get_dir_inode(dir, dentry);
else
inode = zonefs_get_file_inode(dir, dentry);
if (IS_ERR(inode))
return ERR_CAST(inode);
return d_splice_alias(inode, dentry);
}
static int zonefs_readdir_root(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
struct super_block *sb = inode->i_sb;
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
enum zonefs_ztype ztype = ZONEFS_ZTYPE_CNV;
ino_t base_ino = bdev_nr_zones(sb->s_bdev) + 1;
if (ctx->pos >= inode->i_size)
return 0;
if (!dir_emit_dots(file, ctx))
return 0;
if (ctx->pos == 2) {
if (!sbi->s_zgroup[ZONEFS_ZTYPE_CNV].g_nr_zones)
ztype = ZONEFS_ZTYPE_SEQ;
if (!dir_emit(ctx, zonefs_zgroup_name(ztype), 3,
base_ino + ztype, DT_DIR))
return 0;
ctx->pos++;
}
if (ctx->pos == 3 && ztype != ZONEFS_ZTYPE_SEQ) {
ztype = ZONEFS_ZTYPE_SEQ;
if (!dir_emit(ctx, zonefs_zgroup_name(ztype), 3,
base_ino + ztype, DT_DIR))
return 0;
ctx->pos++;
}
return 0;
}
static int zonefs_readdir_zgroup(struct file *file,
struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
struct zonefs_zone_group *zgroup = inode->i_private;
struct super_block *sb = inode->i_sb;
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
struct zonefs_zone *z;
int fname_len;
char *fname;
ino_t ino;
int f;
/*
* The size of zone group directories is equal to the number
* of zone files in the group and does note include the "." and
* ".." entries. Hence the "+ 2" here.
*/
if (ctx->pos >= inode->i_size + 2)
return 0;
if (!dir_emit_dots(file, ctx))
return 0;
fname = kmalloc(ZONEFS_NAME_MAX, GFP_KERNEL);
if (!fname)
return -ENOMEM;
for (f = ctx->pos - 2; f < zgroup->g_nr_zones; f++) {
z = &zgroup->g_zones[f];
ino = z->z_sector >> sbi->s_zone_sectors_shift;
fname_len = snprintf(fname, ZONEFS_NAME_MAX - 1, "%u", f);
if (!dir_emit(ctx, fname, fname_len, ino, DT_REG))
break;
ctx->pos++;
}
kfree(fname);
return 0;
}
static int zonefs_readdir(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
if (inode == d_inode(inode->i_sb->s_root))
return zonefs_readdir_root(file, ctx);
return zonefs_readdir_zgroup(file, ctx);
}
const struct inode_operations zonefs_dir_inode_operations = {
.lookup = zonefs_lookup,
.setattr = zonefs_inode_setattr,
};
const struct file_operations zonefs_dir_operations = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.iterate_shared = zonefs_readdir,
};
struct zonefs_zone_data {
struct super_block *sb;
unsigned int nr_zones[ZONEFS_ZTYPE_MAX];
sector_t cnv_zone_start;
struct blk_zone *zones;
};
static int zonefs_get_zone_info_cb(struct blk_zone *zone, unsigned int idx,
void *data)
{
struct zonefs_zone_data *zd = data;
struct super_block *sb = zd->sb;
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
/*
* We do not care about the first zone: it contains the super block
* and not exposed as a file.
*/
if (!idx)
return 0;
/*
* Count the number of zones that will be exposed as files.
* For sequential zones, we always have as many files as zones.
* FOr conventional zones, the number of files depends on if we have
* conventional zones aggregation enabled.
*/
switch (zone->type) {
case BLK_ZONE_TYPE_CONVENTIONAL:
if (sbi->s_features & ZONEFS_F_AGGRCNV) {
/* One file per set of contiguous conventional zones */
if (!(sbi->s_zgroup[ZONEFS_ZTYPE_CNV].g_nr_zones) ||
zone->start != zd->cnv_zone_start)
sbi->s_zgroup[ZONEFS_ZTYPE_CNV].g_nr_zones++;
zd->cnv_zone_start = zone->start + zone->len;
} else {
/* One file per zone */
sbi->s_zgroup[ZONEFS_ZTYPE_CNV].g_nr_zones++;
}
break;
case BLK_ZONE_TYPE_SEQWRITE_REQ:
case BLK_ZONE_TYPE_SEQWRITE_PREF:
sbi->s_zgroup[ZONEFS_ZTYPE_SEQ].g_nr_zones++;
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_free_zone_info(struct zonefs_zone_data *zd)
{
kvfree(zd->zones);
}
/*
* Create a zone group and populate it with zone files.
*/
static int zonefs_init_zgroup(struct super_block *sb,
struct zonefs_zone_data *zd,
enum zonefs_ztype ztype)
{
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
struct zonefs_zone_group *zgroup = &sbi->s_zgroup[ztype];
struct blk_zone *zone, *next, *end;
struct zonefs_zone *z;
unsigned int n = 0;
int ret;
/* Allocate the zone group. If it is empty, we have nothing to do. */
if (!zgroup->g_nr_zones)
return 0;
zgroup->g_zones = kvcalloc(zgroup->g_nr_zones,
sizeof(struct zonefs_zone), GFP_KERNEL);
if (!zgroup->g_zones)
return -ENOMEM;
/*
* Initialize the zone groups using the device zone information.
* We always skip the first zone as it contains the super block
* and is not use to back a file.
*/
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) != ztype)
continue;
if (WARN_ON_ONCE(n >= zgroup->g_nr_zones))
return -EINVAL;
/*
* 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 (ztype == ZONEFS_ZTYPE_CNV &&
(sbi->s_features & ZONEFS_F_AGGRCNV)) {
for (; next < end; next++) {
if (zonefs_zone_type(next) != ztype)
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;
}
}
z = &zgroup->g_zones[n];
if (ztype == ZONEFS_ZTYPE_CNV)
z->z_flags |= ZONEFS_ZONE_CNV;
z->z_sector = zone->start;
z->z_size = zone->len << SECTOR_SHIFT;
if (z->z_size > bdev_zone_sectors(sb->s_bdev) << SECTOR_SHIFT &&
!(sbi->s_features & ZONEFS_F_AGGRCNV)) {
zonefs_err(sb,
"Invalid zone size %llu (device zone sectors %llu)\n",
z->z_size,
bdev_zone_sectors(sb->s_bdev) << SECTOR_SHIFT);
return -EINVAL;
}
z->z_capacity = min_t(loff_t, MAX_LFS_FILESIZE,
zone->capacity << SECTOR_SHIFT);
z->z_wpoffset = zonefs_check_zone_condition(sb, z, zone);
z->z_mode = S_IFREG | sbi->s_perm;
z->z_uid = sbi->s_uid;
z->z_gid = sbi->s_gid;
/*
* Let zonefs_inode_update_mode() know that we will need
* special initialization of the inode mode the first time
* it is accessed.
*/
z->z_flags |= ZONEFS_ZONE_INIT_MODE;
sb->s_maxbytes = max(z->z_capacity, sb->s_maxbytes);
sbi->s_blocks += z->z_capacity >> sb->s_blocksize_bits;
sbi->s_used_blocks += z->z_wpoffset >> sb->s_blocksize_bits;
/*
* 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 (ztype == ZONEFS_ZTYPE_SEQ &&
(zone->cond == BLK_ZONE_COND_IMP_OPEN ||
zone->cond == BLK_ZONE_COND_EXP_OPEN)) {
ret = zonefs_zone_mgmt(sb, z, REQ_OP_ZONE_CLOSE);
if (ret)
return ret;
}
zonefs_account_active(sb, z);
n++;
}
if (WARN_ON_ONCE(n != zgroup->g_nr_zones))
return -EINVAL;
zonefs_info(sb, "Zone group \"%s\" has %u file%s\n",
zonefs_zgroup_name(ztype),
zgroup->g_nr_zones,
zgroup->g_nr_zones > 1 ? "s" : "");
return 0;
}
static void zonefs_free_zgroups(struct super_block *sb)
{
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
enum zonefs_ztype ztype;
if (!sbi)
return;
for (ztype = 0; ztype < ZONEFS_ZTYPE_MAX; ztype++) {
kvfree(sbi->s_zgroup[ztype].g_zones);
sbi->s_zgroup[ztype].g_zones = NULL;
}
}
/*
* Create a zone group and populate it with zone files.
*/
static int zonefs_init_zgroups(struct super_block *sb)
{
struct zonefs_zone_data zd;
enum zonefs_ztype ztype;
int ret;
/* First get the device zone information */
memset(&zd, 0, sizeof(struct zonefs_zone_data));
zd.sb = sb;
ret = zonefs_get_zone_info(&zd);
if (ret)
goto cleanup;
/* Allocate and initialize the zone groups */
for (ztype = 0; ztype < ZONEFS_ZTYPE_MAX; ztype++) {
ret = zonefs_init_zgroup(sb, &zd, ztype);
if (ret) {
zonefs_info(sb,
"Zone group \"%s\" initialization failed\n",
zonefs_zgroup_name(ztype));
break;
}
}
cleanup:
zonefs_free_zone_info(&zd);
if (ret)
zonefs_free_zgroups(sb);
return ret;
}
/*
* Read super block information from the device.
*/
static int zonefs_read_super(struct super_block *sb)
{
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
struct zonefs_super *super;
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;
}
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 int zonefs_get_zgroup_inodes(struct super_block *sb)
{
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
struct inode *dir_inode;
enum zonefs_ztype ztype;
for (ztype = 0; ztype < ZONEFS_ZTYPE_MAX; ztype++) {
if (!sbi->s_zgroup[ztype].g_nr_zones)
continue;
dir_inode = zonefs_get_zgroup_inode(sb, ztype);
if (IS_ERR(dir_inode))
return PTR_ERR(dir_inode);
sbi->s_zgroup[ztype].g_inode = dir_inode;
}
return 0;
}
static void zonefs_release_zgroup_inodes(struct super_block *sb)
{
struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
enum zonefs_ztype ztype;
if (!sbi)
return;
for (ztype = 0; ztype < ZONEFS_ZTYPE_MAX; ztype++) {
if (sbi->s_zgroup[ztype].g_inode) {
iput(sbi->s_zgroup[ztype].g_inode);
sbi->s_zgroup[ztype].g_inode = NULL;
}
}
}
/*
* 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_sb_info *sbi;
struct inode *inode;
enum zonefs_ztype ztype;
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;
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;
}
/* Initialize the zone groups */
ret = zonefs_init_zgroups(sb);
if (ret)
goto cleanup;
/* Create the 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_mtime = inode->i_atime = inode_set_ctime_current(inode);
inode->i_op = &zonefs_dir_inode_operations;
inode->i_fop = &zonefs_dir_operations;
inode->i_size = 2;
set_nlink(inode, 2);
for (ztype = 0; ztype < ZONEFS_ZTYPE_MAX; ztype++) {
if (sbi->s_zgroup[ztype].g_nr_zones) {
inc_nlink(inode);
inode->i_size++;
}
}
sb->s_root = d_make_root(inode);
if (!sb->s_root)
goto cleanup;
/*
* Take a reference on the zone groups directory inodes
* to keep them in the inode cache.
*/
ret = zonefs_get_zgroup_inodes(sb);
if (ret)
goto cleanup;
ret = zonefs_sysfs_register(sb);
if (ret)
goto cleanup;
return 0;
cleanup:
zonefs_release_zgroup_inodes(sb);
zonefs_free_zgroups(sb);
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);
/* Release the reference on the zone group directory inodes */
zonefs_release_zgroup_inodes(sb);
kill_block_super(sb);
zonefs_sysfs_unregister(sb);
zonefs_free_zgroups(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 = zonefs_sysfs_init();
if (ret)
goto destroy_inodecache;
ret = register_filesystem(&zonefs_type);
if (ret)
goto sysfs_exit;
return 0;
sysfs_exit:
zonefs_sysfs_exit();
destroy_inodecache:
zonefs_destroy_inodecache();
return ret;
}
static void __exit zonefs_exit(void)
{
unregister_filesystem(&zonefs_type);
zonefs_sysfs_exit();
zonefs_destroy_inodecache();
}
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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