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linux/fs/btrfs/super.c
Chris Mason 981a37bab5 btrfs: properly enable async discard when switching from RO->RW 
The async discard uses the BTRFS_FS_DISCARD_RUNNING bit in the fs_info
to force discards off when the filesystem has aborted or we're generally
not able to run discards.  This gets flipped on when we're mounted rw,
and also when we go from ro->rw.

Commit 63a7cb1307 ("btrfs: auto enable discard=async when possible")
enabled async discard by default, and this meant
"mount -o ro /dev/xxx /yyy" had async discards turned on.

Unfortunately, this meant our check in btrfs_remount_cleanup() would see
that discards are already on:

    /* If we toggled discard async */
    if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
	btrfs_test_opt(fs_info, DISCARD_ASYNC))
	    btrfs_discard_resume(fs_info);

So, we'd never call btrfs_discard_resume() when remounting the root
filesystem from ro->rw.

drgn shows this really nicely:

import os
import sys

from drgn.helpers.linux.fs import path_lookup
from drgn import NULL, Object, Type, cast

def btrfs_sb(sb):
    return cast("struct btrfs_fs_info *", sb.s_fs_info)

if len(sys.argv) == 1:
    path = "/"
else:
    path = sys.argv[1]

fs_info = cast("struct btrfs_fs_info *", path_lookup(prog, path).mnt.mnt_sb.s_fs_info)

BTRFS_FS_DISCARD_RUNNING = 1 << prog['BTRFS_FS_DISCARD_RUNNING']
if fs_info.flags & BTRFS_FS_DISCARD_RUNNING:
    print("discard running flag is on")
else:
    print("discard running flag is off")

[root]# mount | grep nvme
/dev/nvme0n1p3 on / type btrfs
(rw,relatime,compress-force=zstd:3,ssd,discard=async,space_cache=v2,subvolid=5,subvol=/)

[root]# ./discard_running.drgn
discard running flag is off

[root]# mount -o remount,discard=sync /
[root]# mount -o remount,discard=async /
[root]# ./discard_running.drgn
discard running flag is on

The fix is to call btrfs_discard_resume() when we're going from ro->rw.
It already checks to make sure the async discard flag is on, so it'll do
the right thing.

Fixes: 63a7cb1307 ("btrfs: auto enable discard=async when possible")
CC: stable@vger.kernel.org # 6.3+
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Chris Mason <clm@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-06 19:44:22 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/backing-dev.h>
#include <linux/mount.h>
#include <linux/writeback.h>
#include <linux/statfs.h>
#include <linux/compat.h>
#include <linux/parser.h>
#include <linux/ctype.h>
#include <linux/namei.h>
#include <linux/miscdevice.h>
#include <linux/magic.h>
#include <linux/slab.h>
#include <linux/ratelimit.h>
#include <linux/crc32c.h>
#include <linux/btrfs.h>
#include "messages.h"
#include "delayed-inode.h"
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "print-tree.h"
#include "props.h"
#include "xattr.h"
#include "bio.h"
#include "export.h"
#include "compression.h"
#include "rcu-string.h"
#include "dev-replace.h"
#include "free-space-cache.h"
#include "backref.h"
#include "space-info.h"
#include "sysfs.h"
#include "zoned.h"
#include "tests/btrfs-tests.h"
#include "block-group.h"
#include "discard.h"
#include "qgroup.h"
#include "raid56.h"
#include "fs.h"
#include "accessors.h"
#include "defrag.h"
#include "dir-item.h"
#include "ioctl.h"
#include "scrub.h"
#include "verity.h"
#include "super.h"
#include "extent-tree.h"
#define CREATE_TRACE_POINTS
#include <trace/events/btrfs.h>
static const struct super_operations btrfs_super_ops;
/*
* Types for mounting the default subvolume and a subvolume explicitly
* requested by subvol=/path. That way the callchain is straightforward and we
* don't have to play tricks with the mount options and recursive calls to
* btrfs_mount.
*
* The new btrfs_root_fs_type also servers as a tag for the bdev_holder.
*/
static struct file_system_type btrfs_fs_type;
static struct file_system_type btrfs_root_fs_type;
static int btrfs_remount(struct super_block *sb, int *flags, char *data);
static void btrfs_put_super(struct super_block *sb)
{
close_ctree(btrfs_sb(sb));
}
enum {
Opt_acl, Opt_noacl,
Opt_clear_cache,
Opt_commit_interval,
Opt_compress,
Opt_compress_force,
Opt_compress_force_type,
Opt_compress_type,
Opt_degraded,
Opt_device,
Opt_fatal_errors,
Opt_flushoncommit, Opt_noflushoncommit,
Opt_max_inline,
Opt_barrier, Opt_nobarrier,
Opt_datacow, Opt_nodatacow,
Opt_datasum, Opt_nodatasum,
Opt_defrag, Opt_nodefrag,
Opt_discard, Opt_nodiscard,
Opt_discard_mode,
Opt_norecovery,
Opt_ratio,
Opt_rescan_uuid_tree,
Opt_skip_balance,
Opt_space_cache, Opt_no_space_cache,
Opt_space_cache_version,
Opt_ssd, Opt_nossd,
Opt_ssd_spread, Opt_nossd_spread,
Opt_subvol,
Opt_subvol_empty,
Opt_subvolid,
Opt_thread_pool,
Opt_treelog, Opt_notreelog,
Opt_user_subvol_rm_allowed,
/* Rescue options */
Opt_rescue,
Opt_usebackuproot,
Opt_nologreplay,
Opt_ignorebadroots,
Opt_ignoredatacsums,
Opt_rescue_all,
/* Deprecated options */
Opt_recovery,
Opt_inode_cache, Opt_noinode_cache,
/* Debugging options */
Opt_check_integrity,
Opt_check_integrity_including_extent_data,
Opt_check_integrity_print_mask,
Opt_enospc_debug, Opt_noenospc_debug,
#ifdef CONFIG_BTRFS_DEBUG
Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
#endif
#ifdef CONFIG_BTRFS_FS_REF_VERIFY
Opt_ref_verify,
#endif
Opt_err,
};
static const match_table_t tokens = {
{Opt_acl, "acl"},
{Opt_noacl, "noacl"},
{Opt_clear_cache, "clear_cache"},
{Opt_commit_interval, "commit=%u"},
{Opt_compress, "compress"},
{Opt_compress_type, "compress=%s"},
{Opt_compress_force, "compress-force"},
{Opt_compress_force_type, "compress-force=%s"},
{Opt_degraded, "degraded"},
{Opt_device, "device=%s"},
{Opt_fatal_errors, "fatal_errors=%s"},
{Opt_flushoncommit, "flushoncommit"},
{Opt_noflushoncommit, "noflushoncommit"},
{Opt_inode_cache, "inode_cache"},
{Opt_noinode_cache, "noinode_cache"},
{Opt_max_inline, "max_inline=%s"},
{Opt_barrier, "barrier"},
{Opt_nobarrier, "nobarrier"},
{Opt_datacow, "datacow"},
{Opt_nodatacow, "nodatacow"},
{Opt_datasum, "datasum"},
{Opt_nodatasum, "nodatasum"},
{Opt_defrag, "autodefrag"},
{Opt_nodefrag, "noautodefrag"},
{Opt_discard, "discard"},
{Opt_discard_mode, "discard=%s"},
{Opt_nodiscard, "nodiscard"},
{Opt_norecovery, "norecovery"},
{Opt_ratio, "metadata_ratio=%u"},
{Opt_rescan_uuid_tree, "rescan_uuid_tree"},
{Opt_skip_balance, "skip_balance"},
{Opt_space_cache, "space_cache"},
{Opt_no_space_cache, "nospace_cache"},
{Opt_space_cache_version, "space_cache=%s"},
{Opt_ssd, "ssd"},
{Opt_nossd, "nossd"},
{Opt_ssd_spread, "ssd_spread"},
{Opt_nossd_spread, "nossd_spread"},
{Opt_subvol, "subvol=%s"},
{Opt_subvol_empty, "subvol="},
{Opt_subvolid, "subvolid=%s"},
{Opt_thread_pool, "thread_pool=%u"},
{Opt_treelog, "treelog"},
{Opt_notreelog, "notreelog"},
{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
/* Rescue options */
{Opt_rescue, "rescue=%s"},
/* Deprecated, with alias rescue=nologreplay */
{Opt_nologreplay, "nologreplay"},
/* Deprecated, with alias rescue=usebackuproot */
{Opt_usebackuproot, "usebackuproot"},
/* Deprecated options */
{Opt_recovery, "recovery"},
/* Debugging options */
{Opt_check_integrity, "check_int"},
{Opt_check_integrity_including_extent_data, "check_int_data"},
{Opt_check_integrity_print_mask, "check_int_print_mask=%u"},
{Opt_enospc_debug, "enospc_debug"},
{Opt_noenospc_debug, "noenospc_debug"},
#ifdef CONFIG_BTRFS_DEBUG
{Opt_fragment_data, "fragment=data"},
{Opt_fragment_metadata, "fragment=metadata"},
{Opt_fragment_all, "fragment=all"},
#endif
#ifdef CONFIG_BTRFS_FS_REF_VERIFY
{Opt_ref_verify, "ref_verify"},
#endif
{Opt_err, NULL},
};
static const match_table_t rescue_tokens = {
{Opt_usebackuproot, "usebackuproot"},
{Opt_nologreplay, "nologreplay"},
{Opt_ignorebadroots, "ignorebadroots"},
{Opt_ignorebadroots, "ibadroots"},
{Opt_ignoredatacsums, "ignoredatacsums"},
{Opt_ignoredatacsums, "idatacsums"},
{Opt_rescue_all, "all"},
{Opt_err, NULL},
};
static bool check_ro_option(struct btrfs_fs_info *fs_info, unsigned long opt,
const char *opt_name)
{
if (fs_info->mount_opt & opt) {
btrfs_err(fs_info, "%s must be used with ro mount option",
opt_name);
return true;
}
return false;
}
static int parse_rescue_options(struct btrfs_fs_info *info, const char *options)
{
char *opts;
char *orig;
char *p;
substring_t args[MAX_OPT_ARGS];
int ret = 0;
opts = kstrdup(options, GFP_KERNEL);
if (!opts)
return -ENOMEM;
orig = opts;
while ((p = strsep(&opts, ":")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, rescue_tokens, args);
switch (token){
case Opt_usebackuproot:
btrfs_info(info,
"trying to use backup root at mount time");
btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
break;
case Opt_nologreplay:
btrfs_set_and_info(info, NOLOGREPLAY,
"disabling log replay at mount time");
break;
case Opt_ignorebadroots:
btrfs_set_and_info(info, IGNOREBADROOTS,
"ignoring bad roots");
break;
case Opt_ignoredatacsums:
btrfs_set_and_info(info, IGNOREDATACSUMS,
"ignoring data csums");
break;
case Opt_rescue_all:
btrfs_info(info, "enabling all of the rescue options");
btrfs_set_and_info(info, IGNOREDATACSUMS,
"ignoring data csums");
btrfs_set_and_info(info, IGNOREBADROOTS,
"ignoring bad roots");
btrfs_set_and_info(info, NOLOGREPLAY,
"disabling log replay at mount time");
break;
case Opt_err:
btrfs_info(info, "unrecognized rescue option '%s'", p);
ret = -EINVAL;
goto out;
default:
break;
}
}
out:
kfree(orig);
return ret;
}
/*
* Regular mount options parser. Everything that is needed only when
* reading in a new superblock is parsed here.
* XXX JDM: This needs to be cleaned up for remount.
*/
int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
unsigned long new_flags)
{
substring_t args[MAX_OPT_ARGS];
char *p, *num;
int intarg;
int ret = 0;
char *compress_type;
bool compress_force = false;
enum btrfs_compression_type saved_compress_type;
int saved_compress_level;
bool saved_compress_force;
int no_compress = 0;
const bool remounting = test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state);
if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
btrfs_set_opt(info->mount_opt, FREE_SPACE_TREE);
else if (btrfs_free_space_cache_v1_active(info)) {
if (btrfs_is_zoned(info)) {
btrfs_info(info,
"zoned: clearing existing space cache");
btrfs_set_super_cache_generation(info->super_copy, 0);
} else {
btrfs_set_opt(info->mount_opt, SPACE_CACHE);
}
}
/*
* Even the options are empty, we still need to do extra check
* against new flags
*/
if (!options)
goto check;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_degraded:
btrfs_info(info, "allowing degraded mounts");
btrfs_set_opt(info->mount_opt, DEGRADED);
break;
case Opt_subvol:
case Opt_subvol_empty:
case Opt_subvolid:
case Opt_device:
/*
* These are parsed by btrfs_parse_subvol_options or
* btrfs_parse_device_options and can be ignored here.
*/
break;
case Opt_nodatasum:
btrfs_set_and_info(info, NODATASUM,
"setting nodatasum");
break;
case Opt_datasum:
if (btrfs_test_opt(info, NODATASUM)) {
if (btrfs_test_opt(info, NODATACOW))
btrfs_info(info,
"setting datasum, datacow enabled");
else
btrfs_info(info, "setting datasum");
}
btrfs_clear_opt(info->mount_opt, NODATACOW);
btrfs_clear_opt(info->mount_opt, NODATASUM);
break;
case Opt_nodatacow:
if (!btrfs_test_opt(info, NODATACOW)) {
if (!btrfs_test_opt(info, COMPRESS) ||
!btrfs_test_opt(info, FORCE_COMPRESS)) {
btrfs_info(info,
"setting nodatacow, compression disabled");
} else {
btrfs_info(info, "setting nodatacow");
}
}
btrfs_clear_opt(info->mount_opt, COMPRESS);
btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
btrfs_set_opt(info->mount_opt, NODATACOW);
btrfs_set_opt(info->mount_opt, NODATASUM);
break;
case Opt_datacow:
btrfs_clear_and_info(info, NODATACOW,
"setting datacow");
break;
case Opt_compress_force:
case Opt_compress_force_type:
compress_force = true;
fallthrough;
case Opt_compress:
case Opt_compress_type:
saved_compress_type = btrfs_test_opt(info,
COMPRESS) ?
info->compress_type : BTRFS_COMPRESS_NONE;
saved_compress_force =
btrfs_test_opt(info, FORCE_COMPRESS);
saved_compress_level = info->compress_level;
if (token == Opt_compress ||
token == Opt_compress_force ||
strncmp(args[0].from, "zlib", 4) == 0) {
compress_type = "zlib";
info->compress_type = BTRFS_COMPRESS_ZLIB;
info->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
/*
* args[0] contains uninitialized data since
* for these tokens we don't expect any
* parameter.
*/
if (token != Opt_compress &&
token != Opt_compress_force)
info->compress_level =
btrfs_compress_str2level(
BTRFS_COMPRESS_ZLIB,
args[0].from + 4);
btrfs_set_opt(info->mount_opt, COMPRESS);
btrfs_clear_opt(info->mount_opt, NODATACOW);
btrfs_clear_opt(info->mount_opt, NODATASUM);
no_compress = 0;
} else if (strncmp(args[0].from, "lzo", 3) == 0) {
compress_type = "lzo";
info->compress_type = BTRFS_COMPRESS_LZO;
info->compress_level = 0;
btrfs_set_opt(info->mount_opt, COMPRESS);
btrfs_clear_opt(info->mount_opt, NODATACOW);
btrfs_clear_opt(info->mount_opt, NODATASUM);
btrfs_set_fs_incompat(info, COMPRESS_LZO);
no_compress = 0;
} else if (strncmp(args[0].from, "zstd", 4) == 0) {
compress_type = "zstd";
info->compress_type = BTRFS_COMPRESS_ZSTD;
info->compress_level =
btrfs_compress_str2level(
BTRFS_COMPRESS_ZSTD,
args[0].from + 4);
btrfs_set_opt(info->mount_opt, COMPRESS);
btrfs_clear_opt(info->mount_opt, NODATACOW);
btrfs_clear_opt(info->mount_opt, NODATASUM);
btrfs_set_fs_incompat(info, COMPRESS_ZSTD);
no_compress = 0;
} else if (strncmp(args[0].from, "no", 2) == 0) {
compress_type = "no";
info->compress_level = 0;
info->compress_type = 0;
btrfs_clear_opt(info->mount_opt, COMPRESS);
btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
compress_force = false;
no_compress++;
} else {
btrfs_err(info, "unrecognized compression value %s",
args[0].from);
ret = -EINVAL;
goto out;
}
if (compress_force) {
btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
} else {
/*
* If we remount from compress-force=xxx to
* compress=xxx, we need clear FORCE_COMPRESS
* flag, otherwise, there is no way for users
* to disable forcible compression separately.
*/
btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
}
if (no_compress == 1) {
btrfs_info(info, "use no compression");
} else if ((info->compress_type != saved_compress_type) ||
(compress_force != saved_compress_force) ||
(info->compress_level != saved_compress_level)) {
btrfs_info(info, "%s %s compression, level %d",
(compress_force) ? "force" : "use",
compress_type, info->compress_level);
}
compress_force = false;
break;
case Opt_ssd:
btrfs_set_and_info(info, SSD,
"enabling ssd optimizations");
btrfs_clear_opt(info->mount_opt, NOSSD);
break;
case Opt_ssd_spread:
btrfs_set_and_info(info, SSD,
"enabling ssd optimizations");
btrfs_set_and_info(info, SSD_SPREAD,
"using spread ssd allocation scheme");
btrfs_clear_opt(info->mount_opt, NOSSD);
break;
case Opt_nossd:
btrfs_set_opt(info->mount_opt, NOSSD);
btrfs_clear_and_info(info, SSD,
"not using ssd optimizations");
fallthrough;
case Opt_nossd_spread:
btrfs_clear_and_info(info, SSD_SPREAD,
"not using spread ssd allocation scheme");
break;
case Opt_barrier:
btrfs_clear_and_info(info, NOBARRIER,
"turning on barriers");
break;
case Opt_nobarrier:
btrfs_set_and_info(info, NOBARRIER,
"turning off barriers");
break;
case Opt_thread_pool:
ret = match_int(&args[0], &intarg);
if (ret) {
btrfs_err(info, "unrecognized thread_pool value %s",
args[0].from);
goto out;
} else if (intarg == 0) {
btrfs_err(info, "invalid value 0 for thread_pool");
ret = -EINVAL;
goto out;
}
info->thread_pool_size = intarg;
break;
case Opt_max_inline:
num = match_strdup(&args[0]);
if (num) {
info->max_inline = memparse(num, NULL);
kfree(num);
if (info->max_inline) {
info->max_inline = min_t(u64,
info->max_inline,
info->sectorsize);
}
btrfs_info(info, "max_inline at %llu",
info->max_inline);
} else {
ret = -ENOMEM;
goto out;
}
break;
case Opt_acl:
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
info->sb->s_flags |= SB_POSIXACL;
break;
#else
btrfs_err(info, "support for ACL not compiled in!");
ret = -EINVAL;
goto out;
#endif
case Opt_noacl:
info->sb->s_flags &= ~SB_POSIXACL;
break;
case Opt_notreelog:
btrfs_set_and_info(info, NOTREELOG,
"disabling tree log");
break;
case Opt_treelog:
btrfs_clear_and_info(info, NOTREELOG,
"enabling tree log");
break;
case Opt_norecovery:
case Opt_nologreplay:
btrfs_warn(info,
"'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
btrfs_set_and_info(info, NOLOGREPLAY,
"disabling log replay at mount time");
break;
case Opt_flushoncommit:
btrfs_set_and_info(info, FLUSHONCOMMIT,
"turning on flush-on-commit");
break;
case Opt_noflushoncommit:
btrfs_clear_and_info(info, FLUSHONCOMMIT,
"turning off flush-on-commit");
break;
case Opt_ratio:
ret = match_int(&args[0], &intarg);
if (ret) {
btrfs_err(info, "unrecognized metadata_ratio value %s",
args[0].from);
goto out;
}
info->metadata_ratio = intarg;
btrfs_info(info, "metadata ratio %u",
info->metadata_ratio);
break;
case Opt_discard:
case Opt_discard_mode:
if (token == Opt_discard ||
strcmp(args[0].from, "sync") == 0) {
btrfs_clear_opt(info->mount_opt, DISCARD_ASYNC);
btrfs_set_and_info(info, DISCARD_SYNC,
"turning on sync discard");
} else if (strcmp(args[0].from, "async") == 0) {
btrfs_clear_opt(info->mount_opt, DISCARD_SYNC);
btrfs_set_and_info(info, DISCARD_ASYNC,
"turning on async discard");
} else {
btrfs_err(info, "unrecognized discard mode value %s",
args[0].from);
ret = -EINVAL;
goto out;
}
btrfs_clear_opt(info->mount_opt, NODISCARD);
break;
case Opt_nodiscard:
btrfs_clear_and_info(info, DISCARD_SYNC,
"turning off discard");
btrfs_clear_and_info(info, DISCARD_ASYNC,
"turning off async discard");
btrfs_set_opt(info->mount_opt, NODISCARD);
break;
case Opt_space_cache:
case Opt_space_cache_version:
/*
* We already set FREE_SPACE_TREE above because we have
* compat_ro(FREE_SPACE_TREE) set, and we aren't going
* to allow v1 to be set for extent tree v2, simply
* ignore this setting if we're extent tree v2.
*/
if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
break;
if (token == Opt_space_cache ||
strcmp(args[0].from, "v1") == 0) {
btrfs_clear_opt(info->mount_opt,
FREE_SPACE_TREE);
btrfs_set_and_info(info, SPACE_CACHE,
"enabling disk space caching");
} else if (strcmp(args[0].from, "v2") == 0) {
btrfs_clear_opt(info->mount_opt,
SPACE_CACHE);
btrfs_set_and_info(info, FREE_SPACE_TREE,
"enabling free space tree");
} else {
btrfs_err(info, "unrecognized space_cache value %s",
args[0].from);
ret = -EINVAL;
goto out;
}
break;
case Opt_rescan_uuid_tree:
btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
break;
case Opt_no_space_cache:
/*
* We cannot operate without the free space tree with
* extent tree v2, ignore this option.
*/
if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
break;
if (btrfs_test_opt(info, SPACE_CACHE)) {
btrfs_clear_and_info(info, SPACE_CACHE,
"disabling disk space caching");
}
if (btrfs_test_opt(info, FREE_SPACE_TREE)) {
btrfs_clear_and_info(info, FREE_SPACE_TREE,
"disabling free space tree");
}
break;
case Opt_inode_cache:
case Opt_noinode_cache:
btrfs_warn(info,
"the 'inode_cache' option is deprecated and has no effect since 5.11");
break;
case Opt_clear_cache:
/*
* We cannot clear the free space tree with extent tree
* v2, ignore this option.
*/
if (btrfs_fs_incompat(info, EXTENT_TREE_V2))
break;
btrfs_set_and_info(info, CLEAR_CACHE,
"force clearing of disk cache");
break;
case Opt_user_subvol_rm_allowed:
btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
break;
case Opt_enospc_debug:
btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
break;
case Opt_noenospc_debug:
btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
break;
case Opt_defrag:
btrfs_set_and_info(info, AUTO_DEFRAG,
"enabling auto defrag");
break;
case Opt_nodefrag:
btrfs_clear_and_info(info, AUTO_DEFRAG,
"disabling auto defrag");
break;
case Opt_recovery:
case Opt_usebackuproot:
btrfs_warn(info,
"'%s' is deprecated, use 'rescue=usebackuproot' instead",
token == Opt_recovery ? "recovery" :
"usebackuproot");
btrfs_info(info,
"trying to use backup root at mount time");
btrfs_set_opt(info->mount_opt, USEBACKUPROOT);
break;
case Opt_skip_balance:
btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
break;
#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
case Opt_check_integrity_including_extent_data:
btrfs_info(info,
"enabling check integrity including extent data");
btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY_DATA);
btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
break;
case Opt_check_integrity:
btrfs_info(info, "enabling check integrity");
btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
break;
case Opt_check_integrity_print_mask:
ret = match_int(&args[0], &intarg);
if (ret) {
btrfs_err(info,
"unrecognized check_integrity_print_mask value %s",
args[0].from);
goto out;
}
info->check_integrity_print_mask = intarg;
btrfs_info(info, "check_integrity_print_mask 0x%x",
info->check_integrity_print_mask);
break;
#else
case Opt_check_integrity_including_extent_data:
case Opt_check_integrity:
case Opt_check_integrity_print_mask:
btrfs_err(info,
"support for check_integrity* not compiled in!");
ret = -EINVAL;
goto out;
#endif
case Opt_fatal_errors:
if (strcmp(args[0].from, "panic") == 0) {
btrfs_set_opt(info->mount_opt,
PANIC_ON_FATAL_ERROR);
} else if (strcmp(args[0].from, "bug") == 0) {
btrfs_clear_opt(info->mount_opt,
PANIC_ON_FATAL_ERROR);
} else {
btrfs_err(info, "unrecognized fatal_errors value %s",
args[0].from);
ret = -EINVAL;
goto out;
}
break;
case Opt_commit_interval:
intarg = 0;
ret = match_int(&args[0], &intarg);
if (ret) {
btrfs_err(info, "unrecognized commit_interval value %s",
args[0].from);
ret = -EINVAL;
goto out;
}
if (intarg == 0) {
btrfs_info(info,
"using default commit interval %us",
BTRFS_DEFAULT_COMMIT_INTERVAL);
intarg = BTRFS_DEFAULT_COMMIT_INTERVAL;
} else if (intarg > 300) {
btrfs_warn(info, "excessive commit interval %d",
intarg);
}
info->commit_interval = intarg;
break;
case Opt_rescue:
ret = parse_rescue_options(info, args[0].from);
if (ret < 0) {
btrfs_err(info, "unrecognized rescue value %s",
args[0].from);
goto out;
}
break;
#ifdef CONFIG_BTRFS_DEBUG
case Opt_fragment_all:
btrfs_info(info, "fragmenting all space");
btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
btrfs_set_opt(info->mount_opt, FRAGMENT_METADATA);
break;
case Opt_fragment_metadata:
btrfs_info(info, "fragmenting metadata");
btrfs_set_opt(info->mount_opt,
FRAGMENT_METADATA);
break;
case Opt_fragment_data:
btrfs_info(info, "fragmenting data");
btrfs_set_opt(info->mount_opt, FRAGMENT_DATA);
break;
#endif
#ifdef CONFIG_BTRFS_FS_REF_VERIFY
case Opt_ref_verify:
btrfs_info(info, "doing ref verification");
btrfs_set_opt(info->mount_opt, REF_VERIFY);
break;
#endif
case Opt_err:
btrfs_err(info, "unrecognized mount option '%s'", p);
ret = -EINVAL;
goto out;
default:
break;
}
}
check:
/* We're read-only, don't have to check. */
if (new_flags & SB_RDONLY)
goto out;
if (check_ro_option(info, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
check_ro_option(info, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
check_ro_option(info, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums"))
ret = -EINVAL;
out:
if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
!btrfs_test_opt(info, FREE_SPACE_TREE) &&
!btrfs_test_opt(info, CLEAR_CACHE)) {
btrfs_err(info, "cannot disable free space tree");
ret = -EINVAL;
}
if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) &&
!btrfs_test_opt(info, FREE_SPACE_TREE)) {
btrfs_err(info, "cannot disable free space tree with block-group-tree feature");
ret = -EINVAL;
}
if (!ret)
ret = btrfs_check_mountopts_zoned(info);
if (!ret && !remounting) {
if (btrfs_test_opt(info, SPACE_CACHE))
btrfs_info(info, "disk space caching is enabled");
if (btrfs_test_opt(info, FREE_SPACE_TREE))
btrfs_info(info, "using free space tree");
}
return ret;
}
/*
* Parse mount options that are required early in the mount process.
*
* All other options will be parsed on much later in the mount process and
* only when we need to allocate a new super block.
*/
static int btrfs_parse_device_options(const char *options, fmode_t flags,
void *holder)
{
substring_t args[MAX_OPT_ARGS];
char *device_name, *opts, *orig, *p;
struct btrfs_device *device = NULL;
int error = 0;
lockdep_assert_held(&uuid_mutex);
if (!options)
return 0;
/*
* strsep changes the string, duplicate it because btrfs_parse_options
* gets called later
*/
opts = kstrdup(options, GFP_KERNEL);
if (!opts)
return -ENOMEM;
orig = opts;
while ((p = strsep(&opts, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
if (token == Opt_device) {
device_name = match_strdup(&args[0]);
if (!device_name) {
error = -ENOMEM;
goto out;
}
device = btrfs_scan_one_device(device_name, flags,
holder);
kfree(device_name);
if (IS_ERR(device)) {
error = PTR_ERR(device);
goto out;
}
}
}
out:
kfree(orig);
return error;
}
/*
* Parse mount options that are related to subvolume id
*
* The value is later passed to mount_subvol()
*/
static int btrfs_parse_subvol_options(const char *options, char **subvol_name,
u64 *subvol_objectid)
{
substring_t args[MAX_OPT_ARGS];
char *opts, *orig, *p;
int error = 0;
u64 subvolid;
if (!options)
return 0;
/*
* strsep changes the string, duplicate it because
* btrfs_parse_device_options gets called later
*/
opts = kstrdup(options, GFP_KERNEL);
if (!opts)
return -ENOMEM;
orig = opts;
while ((p = strsep(&opts, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_subvol:
kfree(*subvol_name);
*subvol_name = match_strdup(&args[0]);
if (!*subvol_name) {
error = -ENOMEM;
goto out;
}
break;
case Opt_subvolid:
error = match_u64(&args[0], &subvolid);
if (error)
goto out;
/* we want the original fs_tree */
if (subvolid == 0)
subvolid = BTRFS_FS_TREE_OBJECTID;
*subvol_objectid = subvolid;
break;
default:
break;
}
}
out:
kfree(orig);
return error;
}
char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
u64 subvol_objectid)
{
struct btrfs_root *root = fs_info->tree_root;
struct btrfs_root *fs_root = NULL;
struct btrfs_root_ref *root_ref;
struct btrfs_inode_ref *inode_ref;
struct btrfs_key key;
struct btrfs_path *path = NULL;
char *name = NULL, *ptr;
u64 dirid;
int len;
int ret;
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto err;
}
name = kmalloc(PATH_MAX, GFP_KERNEL);
if (!name) {
ret = -ENOMEM;
goto err;
}
ptr = name + PATH_MAX - 1;
ptr[0] = '\0';
/*
* Walk up the subvolume trees in the tree of tree roots by root
* backrefs until we hit the top-level subvolume.
*/
while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
key.objectid = subvol_objectid;
key.type = BTRFS_ROOT_BACKREF_KEY;
key.offset = (u64)-1;
ret = btrfs_search_backwards(root, &key, path);
if (ret < 0) {
goto err;
} else if (ret > 0) {
ret = -ENOENT;
goto err;
}
subvol_objectid = key.offset;
root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_root_ref);
len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
ptr -= len + 1;
if (ptr < name) {
ret = -ENAMETOOLONG;
goto err;
}
read_extent_buffer(path->nodes[0], ptr + 1,
(unsigned long)(root_ref + 1), len);
ptr[0] = '/';
dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
btrfs_release_path(path);
fs_root = btrfs_get_fs_root(fs_info, subvol_objectid, true);
if (IS_ERR(fs_root)) {
ret = PTR_ERR(fs_root);
fs_root = NULL;
goto err;
}
/*
* Walk up the filesystem tree by inode refs until we hit the
* root directory.
*/
while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
key.objectid = dirid;
key.type = BTRFS_INODE_REF_KEY;
key.offset = (u64)-1;
ret = btrfs_search_backwards(fs_root, &key, path);
if (ret < 0) {
goto err;
} else if (ret > 0) {
ret = -ENOENT;
goto err;
}
dirid = key.offset;
inode_ref = btrfs_item_ptr(path->nodes[0],
path->slots[0],
struct btrfs_inode_ref);
len = btrfs_inode_ref_name_len(path->nodes[0],
inode_ref);
ptr -= len + 1;
if (ptr < name) {
ret = -ENAMETOOLONG;
goto err;
}
read_extent_buffer(path->nodes[0], ptr + 1,
(unsigned long)(inode_ref + 1), len);
ptr[0] = '/';
btrfs_release_path(path);
}
btrfs_put_root(fs_root);
fs_root = NULL;
}
btrfs_free_path(path);
if (ptr == name + PATH_MAX - 1) {
name[0] = '/';
name[1] = '\0';
} else {
memmove(name, ptr, name + PATH_MAX - ptr);
}
return name;
err:
btrfs_put_root(fs_root);
btrfs_free_path(path);
kfree(name);
return ERR_PTR(ret);
}
static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
{
struct btrfs_root *root = fs_info->tree_root;
struct btrfs_dir_item *di;
struct btrfs_path *path;
struct btrfs_key location;
struct fscrypt_str name = FSTR_INIT("default", 7);
u64 dir_id;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
/*
* Find the "default" dir item which points to the root item that we
* will mount by default if we haven't been given a specific subvolume
* to mount.
*/
dir_id = btrfs_super_root_dir(fs_info->super_copy);
di = btrfs_lookup_dir_item(NULL, root, path, dir_id, &name, 0);
if (IS_ERR(di)) {
btrfs_free_path(path);
return PTR_ERR(di);
}
if (!di) {
/*
* Ok the default dir item isn't there. This is weird since
* it's always been there, but don't freak out, just try and
* mount the top-level subvolume.
*/
btrfs_free_path(path);
*objectid = BTRFS_FS_TREE_OBJECTID;
return 0;
}
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
btrfs_free_path(path);
*objectid = location.objectid;
return 0;
}
static int btrfs_fill_super(struct super_block *sb,
struct btrfs_fs_devices *fs_devices,
void *data)
{
struct inode *inode;
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
int err;
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_magic = BTRFS_SUPER_MAGIC;
sb->s_op = &btrfs_super_ops;
sb->s_d_op = &btrfs_dentry_operations;
sb->s_export_op = &btrfs_export_ops;
#ifdef CONFIG_FS_VERITY
sb->s_vop = &btrfs_verityops;
#endif
sb->s_xattr = btrfs_xattr_handlers;
sb->s_time_gran = 1;
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
sb->s_flags |= SB_POSIXACL;
#endif
sb->s_flags |= SB_I_VERSION;
sb->s_iflags |= SB_I_CGROUPWB;
err = super_setup_bdi(sb);
if (err) {
btrfs_err(fs_info, "super_setup_bdi failed");
return err;
}
err = open_ctree(sb, fs_devices, (char *)data);
if (err) {
btrfs_err(fs_info, "open_ctree failed");
return err;
}
inode = btrfs_iget(sb, BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
btrfs_handle_fs_error(fs_info, err, NULL);
goto fail_close;
}
sb->s_root = d_make_root(inode);
if (!sb->s_root) {
err = -ENOMEM;
goto fail_close;
}
sb->s_flags |= SB_ACTIVE;
return 0;
fail_close:
close_ctree(fs_info);
return err;
}
int btrfs_sync_fs(struct super_block *sb, int wait)
{
struct btrfs_trans_handle *trans;
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
struct btrfs_root *root = fs_info->tree_root;
trace_btrfs_sync_fs(fs_info, wait);
if (!wait) {
filemap_flush(fs_info->btree_inode->i_mapping);
return 0;
}
btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
trans = btrfs_attach_transaction_barrier(root);
if (IS_ERR(trans)) {
/* no transaction, don't bother */
if (PTR_ERR(trans) == -ENOENT) {
/*
* Exit unless we have some pending changes
* that need to go through commit
*/
if (!test_bit(BTRFS_FS_NEED_TRANS_COMMIT,
&fs_info->flags))
return 0;
/*
* A non-blocking test if the fs is frozen. We must not
* start a new transaction here otherwise a deadlock
* happens. The pending operations are delayed to the
* next commit after thawing.
*/
if (sb_start_write_trylock(sb))
sb_end_write(sb);
else
return 0;
trans = btrfs_start_transaction(root, 0);
}
if (IS_ERR(trans))
return PTR_ERR(trans);
}
return btrfs_commit_transaction(trans);
}
static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed)
{
seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s);
*printed = true;
}
static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
{
struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
const char *compress_type;
const char *subvol_name;
bool printed = false;
if (btrfs_test_opt(info, DEGRADED))
seq_puts(seq, ",degraded");
if (btrfs_test_opt(info, NODATASUM))
seq_puts(seq, ",nodatasum");
if (btrfs_test_opt(info, NODATACOW))
seq_puts(seq, ",nodatacow");
if (btrfs_test_opt(info, NOBARRIER))
seq_puts(seq, ",nobarrier");
if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
seq_printf(seq, ",max_inline=%llu", info->max_inline);
if (info->thread_pool_size != min_t(unsigned long,
num_online_cpus() + 2, 8))
seq_printf(seq, ",thread_pool=%u", info->thread_pool_size);
if (btrfs_test_opt(info, COMPRESS)) {
compress_type = btrfs_compress_type2str(info->compress_type);
if (btrfs_test_opt(info, FORCE_COMPRESS))
seq_printf(seq, ",compress-force=%s", compress_type);
else
seq_printf(seq, ",compress=%s", compress_type);
if (info->compress_level)
seq_printf(seq, ":%d", info->compress_level);
}
if (btrfs_test_opt(info, NOSSD))
seq_puts(seq, ",nossd");
if (btrfs_test_opt(info, SSD_SPREAD))
seq_puts(seq, ",ssd_spread");
else if (btrfs_test_opt(info, SSD))
seq_puts(seq, ",ssd");
if (btrfs_test_opt(info, NOTREELOG))
seq_puts(seq, ",notreelog");
if (btrfs_test_opt(info, NOLOGREPLAY))
print_rescue_option(seq, "nologreplay", &printed);
if (btrfs_test_opt(info, USEBACKUPROOT))
print_rescue_option(seq, "usebackuproot", &printed);
if (btrfs_test_opt(info, IGNOREBADROOTS))
print_rescue_option(seq, "ignorebadroots", &printed);
if (btrfs_test_opt(info, IGNOREDATACSUMS))
print_rescue_option(seq, "ignoredatacsums", &printed);
if (btrfs_test_opt(info, FLUSHONCOMMIT))
seq_puts(seq, ",flushoncommit");
if (btrfs_test_opt(info, DISCARD_SYNC))
seq_puts(seq, ",discard");
if (btrfs_test_opt(info, DISCARD_ASYNC))
seq_puts(seq, ",discard=async");
if (!(info->sb->s_flags & SB_POSIXACL))
seq_puts(seq, ",noacl");
if (btrfs_free_space_cache_v1_active(info))
seq_puts(seq, ",space_cache");
else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE))
seq_puts(seq, ",space_cache=v2");
else
seq_puts(seq, ",nospace_cache");
if (btrfs_test_opt(info, RESCAN_UUID_TREE))
seq_puts(seq, ",rescan_uuid_tree");
if (btrfs_test_opt(info, CLEAR_CACHE))
seq_puts(seq, ",clear_cache");
if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED))
seq_puts(seq, ",user_subvol_rm_allowed");
if (btrfs_test_opt(info, ENOSPC_DEBUG))
seq_puts(seq, ",enospc_debug");
if (btrfs_test_opt(info, AUTO_DEFRAG))
seq_puts(seq, ",autodefrag");
if (btrfs_test_opt(info, SKIP_BALANCE))
seq_puts(seq, ",skip_balance");
#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
if (btrfs_test_opt(info, CHECK_INTEGRITY_DATA))
seq_puts(seq, ",check_int_data");
else if (btrfs_test_opt(info, CHECK_INTEGRITY))
seq_puts(seq, ",check_int");
if (info->check_integrity_print_mask)
seq_printf(seq, ",check_int_print_mask=%d",
info->check_integrity_print_mask);
#endif
if (info->metadata_ratio)
seq_printf(seq, ",metadata_ratio=%u", info->metadata_ratio);
if (btrfs_test_opt(info, PANIC_ON_FATAL_ERROR))
seq_puts(seq, ",fatal_errors=panic");
if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
seq_printf(seq, ",commit=%u", info->commit_interval);
#ifdef CONFIG_BTRFS_DEBUG
if (btrfs_test_opt(info, FRAGMENT_DATA))
seq_puts(seq, ",fragment=data");
if (btrfs_test_opt(info, FRAGMENT_METADATA))
seq_puts(seq, ",fragment=metadata");
#endif
if (btrfs_test_opt(info, REF_VERIFY))
seq_puts(seq, ",ref_verify");
seq_printf(seq, ",subvolid=%llu",
BTRFS_I(d_inode(dentry))->root->root_key.objectid);
subvol_name = btrfs_get_subvol_name_from_objectid(info,
BTRFS_I(d_inode(dentry))->root->root_key.objectid);
if (!IS_ERR(subvol_name)) {
seq_puts(seq, ",subvol=");
seq_escape(seq, subvol_name, " \t\n\\");
kfree(subvol_name);
}
return 0;
}
static int btrfs_test_super(struct super_block *s, void *data)
{
struct btrfs_fs_info *p = data;
struct btrfs_fs_info *fs_info = btrfs_sb(s);
return fs_info->fs_devices == p->fs_devices;
}
static int btrfs_set_super(struct super_block *s, void *data)
{
int err = set_anon_super(s, data);
if (!err)
s->s_fs_info = data;
return err;
}
/*
* subvolumes are identified by ino 256
*/
static inline int is_subvolume_inode(struct inode *inode)
{
if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
return 1;
return 0;
}
static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
struct vfsmount *mnt)
{
struct dentry *root;
int ret;
if (!subvol_name) {
if (!subvol_objectid) {
ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
&subvol_objectid);
if (ret) {
root = ERR_PTR(ret);
goto out;
}
}
subvol_name = btrfs_get_subvol_name_from_objectid(
btrfs_sb(mnt->mnt_sb), subvol_objectid);
if (IS_ERR(subvol_name)) {
root = ERR_CAST(subvol_name);
subvol_name = NULL;
goto out;
}
}
root = mount_subtree(mnt, subvol_name);
/* mount_subtree() drops our reference on the vfsmount. */
mnt = NULL;
if (!IS_ERR(root)) {
struct super_block *s = root->d_sb;
struct btrfs_fs_info *fs_info = btrfs_sb(s);
struct inode *root_inode = d_inode(root);
u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
ret = 0;
if (!is_subvolume_inode(root_inode)) {
btrfs_err(fs_info, "'%s' is not a valid subvolume",
subvol_name);
ret = -EINVAL;
}
if (subvol_objectid && root_objectid != subvol_objectid) {
/*
* This will also catch a race condition where a
* subvolume which was passed by ID is renamed and
* another subvolume is renamed over the old location.
*/
btrfs_err(fs_info,
"subvol '%s' does not match subvolid %llu",
subvol_name, subvol_objectid);
ret = -EINVAL;
}
if (ret) {
dput(root);
root = ERR_PTR(ret);
deactivate_locked_super(s);
}
}
out:
mntput(mnt);
kfree(subvol_name);
return root;
}
/*
* Find a superblock for the given device / mount point.
*
* Note: This is based on mount_bdev from fs/super.c with a few additions
* for multiple device setup. Make sure to keep it in sync.
*/
static struct dentry *btrfs_mount_root(struct file_system_type *fs_type,
int flags, const char *device_name, void *data)
{
struct block_device *bdev = NULL;
struct super_block *s;
struct btrfs_device *device = NULL;
struct btrfs_fs_devices *fs_devices = NULL;
struct btrfs_fs_info *fs_info = NULL;
void *new_sec_opts = NULL;
fmode_t mode = FMODE_READ;
int error = 0;
if (!(flags & SB_RDONLY))
mode |= FMODE_WRITE;
if (data) {
error = security_sb_eat_lsm_opts(data, &new_sec_opts);
if (error)
return ERR_PTR(error);
}
/*
* Setup a dummy root and fs_info for test/set super. This is because
* we don't actually fill this stuff out until open_ctree, but we need
* then open_ctree will properly initialize the file system specific
* settings later. btrfs_init_fs_info initializes the static elements
* of the fs_info (locks and such) to make cleanup easier if we find a
* superblock with our given fs_devices later on at sget() time.
*/
fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
if (!fs_info) {
error = -ENOMEM;
goto error_sec_opts;
}
btrfs_init_fs_info(fs_info);
fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);
if (!fs_info->super_copy || !fs_info->super_for_commit) {
error = -ENOMEM;
goto error_fs_info;
}
mutex_lock(&uuid_mutex);
error = btrfs_parse_device_options(data, mode, fs_type);
if (error) {
mutex_unlock(&uuid_mutex);
goto error_fs_info;
}
device = btrfs_scan_one_device(device_name, mode, fs_type);
if (IS_ERR(device)) {
mutex_unlock(&uuid_mutex);
error = PTR_ERR(device);
goto error_fs_info;
}
fs_devices = device->fs_devices;
fs_info->fs_devices = fs_devices;
error = btrfs_open_devices(fs_devices, mode, fs_type);
mutex_unlock(&uuid_mutex);
if (error)
goto error_fs_info;
if (!(flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
error = -EACCES;
goto error_close_devices;
}
bdev = fs_devices->latest_dev->bdev;
s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | SB_NOSEC,
fs_info);
if (IS_ERR(s)) {
error = PTR_ERR(s);
goto error_close_devices;
}
if (s->s_root) {
btrfs_close_devices(fs_devices);
btrfs_free_fs_info(fs_info);
if ((flags ^ s->s_flags) & SB_RDONLY)
error = -EBUSY;
} else {
snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s", fs_type->name,
s->s_id);
btrfs_sb(s)->bdev_holder = fs_type;
error = btrfs_fill_super(s, fs_devices, data);
}
if (!error)
error = security_sb_set_mnt_opts(s, new_sec_opts, 0, NULL);
security_free_mnt_opts(&new_sec_opts);
if (error) {
deactivate_locked_super(s);
return ERR_PTR(error);
}
return dget(s->s_root);
error_close_devices:
btrfs_close_devices(fs_devices);
error_fs_info:
btrfs_free_fs_info(fs_info);
error_sec_opts:
security_free_mnt_opts(&new_sec_opts);
return ERR_PTR(error);
}
/*
* Mount function which is called by VFS layer.
*
* In order to allow mounting a subvolume directly, btrfs uses mount_subtree()
* which needs vfsmount* of device's root (/). This means device's root has to
* be mounted internally in any case.
*
* Operation flow:
* 1. Parse subvol id related options for later use in mount_subvol().
*
* 2. Mount device's root (/) by calling vfs_kern_mount().
*
* NOTE: vfs_kern_mount() is used by VFS to call btrfs_mount() in the
* first place. In order to avoid calling btrfs_mount() again, we use
* different file_system_type which is not registered to VFS by
* register_filesystem() (btrfs_root_fs_type). As a result,
* btrfs_mount_root() is called. The return value will be used by
* mount_subtree() in mount_subvol().
*
* 3. Call mount_subvol() to get the dentry of subvolume. Since there is
* "btrfs subvolume set-default", mount_subvol() is called always.
*/
static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
const char *device_name, void *data)
{
struct vfsmount *mnt_root;
struct dentry *root;
char *subvol_name = NULL;
u64 subvol_objectid = 0;
int error = 0;
error = btrfs_parse_subvol_options(data, &subvol_name,
&subvol_objectid);
if (error) {
kfree(subvol_name);
return ERR_PTR(error);
}
/* mount device's root (/) */
mnt_root = vfs_kern_mount(&btrfs_root_fs_type, flags, device_name, data);
if (PTR_ERR_OR_ZERO(mnt_root) == -EBUSY) {
if (flags & SB_RDONLY) {
mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
flags & ~SB_RDONLY, device_name, data);
} else {
mnt_root = vfs_kern_mount(&btrfs_root_fs_type,
flags | SB_RDONLY, device_name, data);
if (IS_ERR(mnt_root)) {
root = ERR_CAST(mnt_root);
kfree(subvol_name);
goto out;
}
down_write(&mnt_root->mnt_sb->s_umount);
error = btrfs_remount(mnt_root->mnt_sb, &flags, NULL);
up_write(&mnt_root->mnt_sb->s_umount);
if (error < 0) {
root = ERR_PTR(error);
mntput(mnt_root);
kfree(subvol_name);
goto out;
}
}
}
if (IS_ERR(mnt_root)) {
root = ERR_CAST(mnt_root);
kfree(subvol_name);
goto out;
}
/* mount_subvol() will free subvol_name and mnt_root */
root = mount_subvol(subvol_name, subvol_objectid, mnt_root);
out:
return root;
}
static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
u32 new_pool_size, u32 old_pool_size)
{
if (new_pool_size == old_pool_size)
return;
fs_info->thread_pool_size = new_pool_size;
btrfs_info(fs_info, "resize thread pool %d -> %d",
old_pool_size, new_pool_size);
btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->hipri_workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
workqueue_set_max_active(fs_info->endio_workers, new_pool_size);
workqueue_set_max_active(fs_info->endio_meta_workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
}
static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
unsigned long old_opts, int flags)
{
if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
(!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
(flags & SB_RDONLY))) {
/* wait for any defraggers to finish */
wait_event(fs_info->transaction_wait,
(atomic_read(&fs_info->defrag_running) == 0));
if (flags & SB_RDONLY)
sync_filesystem(fs_info->sb);
}
}
static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
unsigned long old_opts)
{
const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
/*
* We need to cleanup all defragable inodes if the autodefragment is
* close or the filesystem is read only.
*/
if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
(!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) || sb_rdonly(fs_info->sb))) {
btrfs_cleanup_defrag_inodes(fs_info);
}
/* If we toggled discard async */
if (!btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
btrfs_test_opt(fs_info, DISCARD_ASYNC))
btrfs_discard_resume(fs_info);
else if (btrfs_raw_test_opt(old_opts, DISCARD_ASYNC) &&
!btrfs_test_opt(fs_info, DISCARD_ASYNC))
btrfs_discard_cleanup(fs_info);
/* If we toggled space cache */
if (cache_opt != btrfs_free_space_cache_v1_active(fs_info))
btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
}
static int btrfs_remount(struct super_block *sb, int *flags, char *data)
{
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
unsigned old_flags = sb->s_flags;
unsigned long old_opts = fs_info->mount_opt;
unsigned long old_compress_type = fs_info->compress_type;
u64 old_max_inline = fs_info->max_inline;
u32 old_thread_pool_size = fs_info->thread_pool_size;
u32 old_metadata_ratio = fs_info->metadata_ratio;
int ret;
sync_filesystem(sb);
set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
if (data) {
void *new_sec_opts = NULL;
ret = security_sb_eat_lsm_opts(data, &new_sec_opts);
if (!ret)
ret = security_sb_remount(sb, new_sec_opts);
security_free_mnt_opts(&new_sec_opts);
if (ret)
goto restore;
}
ret = btrfs_parse_options(fs_info, data, *flags);
if (ret)
goto restore;
ret = btrfs_check_features(fs_info, !(*flags & SB_RDONLY));
if (ret < 0)
goto restore;
btrfs_remount_begin(fs_info, old_opts, *flags);
btrfs_resize_thread_pool(fs_info,
fs_info->thread_pool_size, old_thread_pool_size);
if ((bool)btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=
(bool)btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
(!sb_rdonly(sb) || (*flags & SB_RDONLY))) {
btrfs_warn(fs_info,
"remount supports changing free space tree only from ro to rw");
/* Make sure free space cache options match the state on disk */
if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
}
if (btrfs_free_space_cache_v1_active(fs_info)) {
btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);
btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
}
}
if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
goto out;
if (*flags & SB_RDONLY) {
/*
* this also happens on 'umount -rf' or on shutdown, when
* the filesystem is busy.
*/
cancel_work_sync(&fs_info->async_reclaim_work);
cancel_work_sync(&fs_info->async_data_reclaim_work);
btrfs_discard_cleanup(fs_info);
/* wait for the uuid_scan task to finish */
down(&fs_info->uuid_tree_rescan_sem);
/* avoid complains from lockdep et al. */
up(&fs_info->uuid_tree_rescan_sem);
btrfs_set_sb_rdonly(sb);
/*
* Setting SB_RDONLY will put the cleaner thread to
* sleep at the next loop if it's already active.
* If it's already asleep, we'll leave unused block
* groups on disk until we're mounted read-write again
* unless we clean them up here.
*/
btrfs_delete_unused_bgs(fs_info);
/*
* The cleaner task could be already running before we set the
* flag BTRFS_FS_STATE_RO (and SB_RDONLY in the superblock).
* We must make sure that after we finish the remount, i.e. after
* we call btrfs_commit_super(), the cleaner can no longer start
* a transaction - either because it was dropping a dead root,
* running delayed iputs or deleting an unused block group (the
* cleaner picked a block group from the list of unused block
* groups before we were able to in the previous call to
* btrfs_delete_unused_bgs()).
*/
wait_on_bit(&fs_info->flags, BTRFS_FS_CLEANER_RUNNING,
TASK_UNINTERRUPTIBLE);
/*
* We've set the superblock to RO mode, so we might have made
* the cleaner task sleep without running all pending delayed
* iputs. Go through all the delayed iputs here, so that if an
* unmount happens without remounting RW we don't end up at
* finishing close_ctree() with a non-empty list of delayed
* iputs.
*/
btrfs_run_delayed_iputs(fs_info);
btrfs_dev_replace_suspend_for_unmount(fs_info);
btrfs_scrub_cancel(fs_info);
btrfs_pause_balance(fs_info);
/*
* Pause the qgroup rescan worker if it is running. We don't want
* it to be still running after we are in RO mode, as after that,
* by the time we unmount, it might have left a transaction open,
* so we would leak the transaction and/or crash.
*/
btrfs_qgroup_wait_for_completion(fs_info, false);
ret = btrfs_commit_super(fs_info);
if (ret)
goto restore;
} else {
if (BTRFS_FS_ERROR(fs_info)) {
btrfs_err(fs_info,
"Remounting read-write after error is not allowed");
ret = -EINVAL;
goto restore;
}
if (fs_info->fs_devices->rw_devices == 0) {
ret = -EACCES;
goto restore;
}
if (!btrfs_check_rw_degradable(fs_info, NULL)) {
btrfs_warn(fs_info,
"too many missing devices, writable remount is not allowed");
ret = -EACCES;
goto restore;
}
if (btrfs_super_log_root(fs_info->super_copy) != 0) {
btrfs_warn(fs_info,
"mount required to replay tree-log, cannot remount read-write");
ret = -EINVAL;
goto restore;
}
/*
* NOTE: when remounting with a change that does writes, don't
* put it anywhere above this point, as we are not sure to be
* safe to write until we pass the above checks.
*/
ret = btrfs_start_pre_rw_mount(fs_info);
if (ret)
goto restore;
btrfs_clear_sb_rdonly(sb);
set_bit(BTRFS_FS_OPEN, &fs_info->flags);
/*
* If we've gone from readonly -> read/write, we need to get
* our sync/async discard lists in the right state.
*/
btrfs_discard_resume(fs_info);
}
out:
/*
* We need to set SB_I_VERSION here otherwise it'll get cleared by VFS,
* since the absence of the flag means it can be toggled off by remount.
*/
*flags |= SB_I_VERSION;
wake_up_process(fs_info->transaction_kthread);
btrfs_remount_cleanup(fs_info, old_opts);
btrfs_clear_oneshot_options(fs_info);
clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
return 0;
restore:
/* We've hit an error - don't reset SB_RDONLY */
if (sb_rdonly(sb))
old_flags |= SB_RDONLY;
if (!(old_flags & SB_RDONLY))
clear_bit(BTRFS_FS_STATE_RO, &fs_info->fs_state);
sb->s_flags = old_flags;
fs_info->mount_opt = old_opts;
fs_info->compress_type = old_compress_type;
fs_info->max_inline = old_max_inline;
btrfs_resize_thread_pool(fs_info,
old_thread_pool_size, fs_info->thread_pool_size);
fs_info->metadata_ratio = old_metadata_ratio;
btrfs_remount_cleanup(fs_info, old_opts);
clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
return ret;
}
/* Used to sort the devices by max_avail(descending sort) */
static int btrfs_cmp_device_free_bytes(const void *a, const void *b)
{
const struct btrfs_device_info *dev_info1 = a;
const struct btrfs_device_info *dev_info2 = b;
if (dev_info1->max_avail > dev_info2->max_avail)
return -1;
else if (dev_info1->max_avail < dev_info2->max_avail)
return 1;
return 0;
}
/*
* sort the devices by max_avail, in which max free extent size of each device
* is stored.(Descending Sort)
*/
static inline void btrfs_descending_sort_devices(
struct btrfs_device_info *devices,
size_t nr_devices)
{
sort(devices, nr_devices, sizeof(struct btrfs_device_info),
btrfs_cmp_device_free_bytes, NULL);
}
/*
* The helper to calc the free space on the devices that can be used to store
* file data.
*/
static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
u64 *free_bytes)
{
struct btrfs_device_info *devices_info;
struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
struct btrfs_device *device;
u64 type;
u64 avail_space;
u64 min_stripe_size;
int num_stripes = 1;
int i = 0, nr_devices;
const struct btrfs_raid_attr *rattr;
/*
* We aren't under the device list lock, so this is racy-ish, but good
* enough for our purposes.
*/
nr_devices = fs_info->fs_devices->open_devices;
if (!nr_devices) {
smp_mb();
nr_devices = fs_info->fs_devices->open_devices;
ASSERT(nr_devices);
if (!nr_devices) {
*free_bytes = 0;
return 0;
}
}
devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
GFP_KERNEL);
if (!devices_info)
return -ENOMEM;
/* calc min stripe number for data space allocation */
type = btrfs_data_alloc_profile(fs_info);
rattr = &btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)];
if (type & BTRFS_BLOCK_GROUP_RAID0)
num_stripes = nr_devices;
else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
num_stripes = rattr->ncopies;
else if (type & BTRFS_BLOCK_GROUP_RAID10)
num_stripes = 4;
/* Adjust for more than 1 stripe per device */
min_stripe_size = rattr->dev_stripes * BTRFS_STRIPE_LEN;
rcu_read_lock();
list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA,
&device->dev_state) ||
!device->bdev ||
test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state))
continue;
if (i >= nr_devices)
break;
avail_space = device->total_bytes - device->bytes_used;
/* align with stripe_len */
avail_space = rounddown(avail_space, BTRFS_STRIPE_LEN);
/*
* Ensure we have at least min_stripe_size on top of the
* reserved space on the device.
*/
if (avail_space <= BTRFS_DEVICE_RANGE_RESERVED + min_stripe_size)
continue;
avail_space -= BTRFS_DEVICE_RANGE_RESERVED;
devices_info[i].dev = device;
devices_info[i].max_avail = avail_space;
i++;
}
rcu_read_unlock();
nr_devices = i;
btrfs_descending_sort_devices(devices_info, nr_devices);
i = nr_devices - 1;
avail_space = 0;
while (nr_devices >= rattr->devs_min) {
num_stripes = min(num_stripes, nr_devices);
if (devices_info[i].max_avail >= min_stripe_size) {
int j;
u64 alloc_size;
avail_space += devices_info[i].max_avail * num_stripes;
alloc_size = devices_info[i].max_avail;
for (j = i + 1 - num_stripes; j <= i; j++)
devices_info[j].max_avail -= alloc_size;
}
i--;
nr_devices--;
}
kfree(devices_info);
*free_bytes = avail_space;
return 0;
}
/*
* Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
*
* If there's a redundant raid level at DATA block groups, use the respective
* multiplier to scale the sizes.
*
* Unused device space usage is based on simulating the chunk allocator
* algorithm that respects the device sizes and order of allocations. This is
* a close approximation of the actual use but there are other factors that may
* change the result (like a new metadata chunk).
*
* If metadata is exhausted, f_bavail will be 0.
*/
static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
struct btrfs_super_block *disk_super = fs_info->super_copy;
struct btrfs_space_info *found;
u64 total_used = 0;
u64 total_free_data = 0;
u64 total_free_meta = 0;
u32 bits = fs_info->sectorsize_bits;
__be32 *fsid = (__be32 *)fs_info->fs_devices->fsid;
unsigned factor = 1;
struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
int ret;
u64 thresh = 0;
int mixed = 0;
list_for_each_entry(found, &fs_info->space_info, list) {
if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
int i;
total_free_data += found->disk_total - found->disk_used;
total_free_data -=
btrfs_account_ro_block_groups_free_space(found);
for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
if (!list_empty(&found->block_groups[i]))
factor = btrfs_bg_type_to_factor(
btrfs_raid_array[i].bg_flag);
}
}
/*
* Metadata in mixed block group profiles are accounted in data
*/
if (!mixed && found->flags & BTRFS_BLOCK_GROUP_METADATA) {
if (found->flags & BTRFS_BLOCK_GROUP_DATA)
mixed = 1;
else
total_free_meta += found->disk_total -
found->disk_used;
}
total_used += found->disk_used;
}
buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
buf->f_blocks >>= bits;
buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
/* Account global block reserve as used, it's in logical size already */
spin_lock(&block_rsv->lock);
/* Mixed block groups accounting is not byte-accurate, avoid overflow */
if (buf->f_bfree >= block_rsv->size >> bits)
buf->f_bfree -= block_rsv->size >> bits;
else
buf->f_bfree = 0;
spin_unlock(&block_rsv->lock);
buf->f_bavail = div_u64(total_free_data, factor);
ret = btrfs_calc_avail_data_space(fs_info, &total_free_data);
if (ret)
return ret;
buf->f_bavail += div_u64(total_free_data, factor);
buf->f_bavail = buf->f_bavail >> bits;
/*
* We calculate the remaining metadata space minus global reserve. If
* this is (supposedly) smaller than zero, there's no space. But this
* does not hold in practice, the exhausted state happens where's still
* some positive delta. So we apply some guesswork and compare the
* delta to a 4M threshold. (Practically observed delta was ~2M.)
*
* We probably cannot calculate the exact threshold value because this
* depends on the internal reservations requested by various
* operations, so some operations that consume a few metadata will
* succeed even if the Avail is zero. But this is better than the other
* way around.
*/
thresh = SZ_4M;
/*
* We only want to claim there's no available space if we can no longer
* allocate chunks for our metadata profile and our global reserve will
* not fit in the free metadata space. If we aren't ->full then we
* still can allocate chunks and thus are fine using the currently
* calculated f_bavail.
*/
if (!mixed && block_rsv->space_info->full &&
total_free_meta - thresh < block_rsv->size)
buf->f_bavail = 0;
buf->f_type = BTRFS_SUPER_MAGIC;
buf->f_bsize = dentry->d_sb->s_blocksize;
buf->f_namelen = BTRFS_NAME_LEN;
/* We treat it as constant endianness (it doesn't matter _which_)
because we want the fsid to come out the same whether mounted
on a big-endian or little-endian host */
buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
/* Mask in the root object ID too, to disambiguate subvols */
buf->f_fsid.val[0] ^=
BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
buf->f_fsid.val[1] ^=
BTRFS_I(d_inode(dentry))->root->root_key.objectid;
return 0;
}
static void btrfs_kill_super(struct super_block *sb)
{
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
kill_anon_super(sb);
btrfs_free_fs_info(fs_info);
}
static struct file_system_type btrfs_fs_type = {
.owner = THIS_MODULE,
.name = "btrfs",
.mount = btrfs_mount,
.kill_sb = btrfs_kill_super,
.fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
};
static struct file_system_type btrfs_root_fs_type = {
.owner = THIS_MODULE,
.name = "btrfs",
.mount = btrfs_mount_root,
.kill_sb = btrfs_kill_super,
.fs_flags = FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA | FS_ALLOW_IDMAP,
};
MODULE_ALIAS_FS("btrfs");
static int btrfs_control_open(struct inode *inode, struct file *file)
{
/*
* The control file's private_data is used to hold the
* transaction when it is started and is used to keep
* track of whether a transaction is already in progress.
*/
file->private_data = NULL;
return 0;
}
/*
* Used by /dev/btrfs-control for devices ioctls.
*/
static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct btrfs_ioctl_vol_args *vol;
struct btrfs_device *device = NULL;
dev_t devt = 0;
int ret = -ENOTTY;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
vol = memdup_user((void __user *)arg, sizeof(*vol));
if (IS_ERR(vol))
return PTR_ERR(vol);
vol->name[BTRFS_PATH_NAME_MAX] = '\0';
switch (cmd) {
case BTRFS_IOC_SCAN_DEV:
mutex_lock(&uuid_mutex);
device = btrfs_scan_one_device(vol->name, FMODE_READ,
&btrfs_root_fs_type);
ret = PTR_ERR_OR_ZERO(device);
mutex_unlock(&uuid_mutex);
break;
case BTRFS_IOC_FORGET_DEV:
if (vol->name[0] != 0) {
ret = lookup_bdev(vol->name, &devt);
if (ret)
break;
}
ret = btrfs_forget_devices(devt);
break;
case BTRFS_IOC_DEVICES_READY:
mutex_lock(&uuid_mutex);
device = btrfs_scan_one_device(vol->name, FMODE_READ,
&btrfs_root_fs_type);
if (IS_ERR(device)) {
mutex_unlock(&uuid_mutex);
ret = PTR_ERR(device);
break;
}
ret = !(device->fs_devices->num_devices ==
device->fs_devices->total_devices);
mutex_unlock(&uuid_mutex);
break;
case BTRFS_IOC_GET_SUPPORTED_FEATURES:
ret = btrfs_ioctl_get_supported_features((void __user*)arg);
break;
}
kfree(vol);
return ret;
}
static int btrfs_freeze(struct super_block *sb)
{
struct btrfs_trans_handle *trans;
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
struct btrfs_root *root = fs_info->tree_root;
set_bit(BTRFS_FS_FROZEN, &fs_info->flags);
/*
* We don't need a barrier here, we'll wait for any transaction that
* could be in progress on other threads (and do delayed iputs that
* we want to avoid on a frozen filesystem), or do the commit
* ourselves.
*/
trans = btrfs_attach_transaction_barrier(root);
if (IS_ERR(trans)) {
/* no transaction, don't bother */
if (PTR_ERR(trans) == -ENOENT)
return 0;
return PTR_ERR(trans);
}
return btrfs_commit_transaction(trans);
}
static int check_dev_super(struct btrfs_device *dev)
{
struct btrfs_fs_info *fs_info = dev->fs_info;
struct btrfs_super_block *sb;
u16 csum_type;
int ret = 0;
/* This should be called with fs still frozen. */
ASSERT(test_bit(BTRFS_FS_FROZEN, &fs_info->flags));
/* Missing dev, no need to check. */
if (!dev->bdev)
return 0;
/* Only need to check the primary super block. */
sb = btrfs_read_dev_one_super(dev->bdev, 0, true);
if (IS_ERR(sb))
return PTR_ERR(sb);
/* Verify the checksum. */
csum_type = btrfs_super_csum_type(sb);
if (csum_type != btrfs_super_csum_type(fs_info->super_copy)) {
btrfs_err(fs_info, "csum type changed, has %u expect %u",
csum_type, btrfs_super_csum_type(fs_info->super_copy));
ret = -EUCLEAN;
goto out;
}
if (btrfs_check_super_csum(fs_info, sb)) {
btrfs_err(fs_info, "csum for on-disk super block no longer matches");
ret = -EUCLEAN;
goto out;
}
/* Btrfs_validate_super() includes fsid check against super->fsid. */
ret = btrfs_validate_super(fs_info, sb, 0);
if (ret < 0)
goto out;
if (btrfs_super_generation(sb) != fs_info->last_trans_committed) {
btrfs_err(fs_info, "transid mismatch, has %llu expect %llu",
btrfs_super_generation(sb),
fs_info->last_trans_committed);
ret = -EUCLEAN;
goto out;
}
out:
btrfs_release_disk_super(sb);
return ret;
}
static int btrfs_unfreeze(struct super_block *sb)
{
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
struct btrfs_device *device;
int ret = 0;
/*
* Make sure the fs is not changed by accident (like hibernation then
* modified by other OS).
* If we found anything wrong, we mark the fs error immediately.
*
* And since the fs is frozen, no one can modify the fs yet, thus
* we don't need to hold device_list_mutex.
*/
list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
ret = check_dev_super(device);
if (ret < 0) {
btrfs_handle_fs_error(fs_info, ret,
"super block on devid %llu got modified unexpectedly",
device->devid);
break;
}
}
clear_bit(BTRFS_FS_FROZEN, &fs_info->flags);
/*
* We still return 0, to allow VFS layer to unfreeze the fs even the
* above checks failed. Since the fs is either fine or read-only, we're
* safe to continue, without causing further damage.
*/
return 0;
}
static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
{
struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
/*
* There should be always a valid pointer in latest_dev, it may be stale
* for a short moment in case it's being deleted but still valid until
* the end of RCU grace period.
*/
rcu_read_lock();
seq_escape(m, btrfs_dev_name(fs_info->fs_devices->latest_dev), " \t\n\\");
rcu_read_unlock();
return 0;
}
static const struct super_operations btrfs_super_ops = {
.drop_inode = btrfs_drop_inode,
.evict_inode = btrfs_evict_inode,
.put_super = btrfs_put_super,
.sync_fs = btrfs_sync_fs,
.show_options = btrfs_show_options,
.show_devname = btrfs_show_devname,
.alloc_inode = btrfs_alloc_inode,
.destroy_inode = btrfs_destroy_inode,
.free_inode = btrfs_free_inode,
.statfs = btrfs_statfs,
.remount_fs = btrfs_remount,
.freeze_fs = btrfs_freeze,
.unfreeze_fs = btrfs_unfreeze,
};
static const struct file_operations btrfs_ctl_fops = {
.open = btrfs_control_open,
.unlocked_ioctl = btrfs_control_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.owner = THIS_MODULE,
.llseek = noop_llseek,
};
static struct miscdevice btrfs_misc = {
.minor = BTRFS_MINOR,
.name = "btrfs-control",
.fops = &btrfs_ctl_fops
};
MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
MODULE_ALIAS("devname:btrfs-control");
static int __init btrfs_interface_init(void)
{
return misc_register(&btrfs_misc);
}
static __cold void btrfs_interface_exit(void)
{
misc_deregister(&btrfs_misc);
}
static int __init btrfs_print_mod_info(void)
{
static const char options[] = ""
#ifdef CONFIG_BTRFS_DEBUG
", debug=on"
#endif
#ifdef CONFIG_BTRFS_ASSERT
", assert=on"
#endif
#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
", integrity-checker=on"
#endif
#ifdef CONFIG_BTRFS_FS_REF_VERIFY
", ref-verify=on"
#endif
#ifdef CONFIG_BLK_DEV_ZONED
", zoned=yes"
#else
", zoned=no"
#endif
#ifdef CONFIG_FS_VERITY
", fsverity=yes"
#else
", fsverity=no"
#endif
;
pr_info("Btrfs loaded%s\n", options);
return 0;
}
static int register_btrfs(void)
{
return register_filesystem(&btrfs_fs_type);
}
static void unregister_btrfs(void)
{
unregister_filesystem(&btrfs_fs_type);
}
/* Helper structure for long init/exit functions. */
struct init_sequence {
int (*init_func)(void);
/* Can be NULL if the init_func doesn't need cleanup. */
void (*exit_func)(void);
};
static const struct init_sequence mod_init_seq[] = {
{
.init_func = btrfs_props_init,
.exit_func = NULL,
}, {
.init_func = btrfs_init_sysfs,
.exit_func = btrfs_exit_sysfs,
}, {
.init_func = btrfs_init_compress,
.exit_func = btrfs_exit_compress,
}, {
.init_func = btrfs_init_cachep,
.exit_func = btrfs_destroy_cachep,
}, {
.init_func = btrfs_transaction_init,
.exit_func = btrfs_transaction_exit,
}, {
.init_func = btrfs_ctree_init,
.exit_func = btrfs_ctree_exit,
}, {
.init_func = btrfs_free_space_init,
.exit_func = btrfs_free_space_exit,
}, {
.init_func = extent_state_init_cachep,
.exit_func = extent_state_free_cachep,
}, {
.init_func = extent_buffer_init_cachep,
.exit_func = extent_buffer_free_cachep,
}, {
.init_func = btrfs_bioset_init,
.exit_func = btrfs_bioset_exit,
}, {
.init_func = extent_map_init,
.exit_func = extent_map_exit,
}, {
.init_func = ordered_data_init,
.exit_func = ordered_data_exit,
}, {
.init_func = btrfs_delayed_inode_init,
.exit_func = btrfs_delayed_inode_exit,
}, {
.init_func = btrfs_auto_defrag_init,
.exit_func = btrfs_auto_defrag_exit,
}, {
.init_func = btrfs_delayed_ref_init,
.exit_func = btrfs_delayed_ref_exit,
}, {
.init_func = btrfs_prelim_ref_init,
.exit_func = btrfs_prelim_ref_exit,
}, {
.init_func = btrfs_interface_init,
.exit_func = btrfs_interface_exit,
}, {
.init_func = btrfs_print_mod_info,
.exit_func = NULL,
}, {
.init_func = btrfs_run_sanity_tests,
.exit_func = NULL,
}, {
.init_func = register_btrfs,
.exit_func = unregister_btrfs,
}
};
static bool mod_init_result[ARRAY_SIZE(mod_init_seq)];
static __always_inline void btrfs_exit_btrfs_fs(void)
{
int i;
for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) {
if (!mod_init_result[i])
continue;
if (mod_init_seq[i].exit_func)
mod_init_seq[i].exit_func();
mod_init_result[i] = false;
}
}
static void __exit exit_btrfs_fs(void)
{
btrfs_exit_btrfs_fs();
btrfs_cleanup_fs_uuids();
}
static int __init init_btrfs_fs(void)
{
int ret;
int i;
for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) {
ASSERT(!mod_init_result[i]);
ret = mod_init_seq[i].init_func();
if (ret < 0) {
btrfs_exit_btrfs_fs();
return ret;
}
mod_init_result[i] = true;
}
return 0;
}
late_initcall(init_btrfs_fs);
module_exit(exit_btrfs_fs)
MODULE_LICENSE("GPL");
MODULE_SOFTDEP("pre: crc32c");
MODULE_SOFTDEP("pre: xxhash64");
MODULE_SOFTDEP("pre: sha256");
MODULE_SOFTDEP("pre: blake2b-256");
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