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android-kvm / linux / 700b7940526d31117fd20b7ed31156df134fbe7f / . / fs / btrfs / super.c
blob: 93f52ee85f6fe9735f379ff9fae3169eba042eb6 [file] [log] [blame]
// 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"
#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 (!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);
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;
if (!strstr(crc32c_impl(), "generic"))
set_bit(BTRFS_FS_CSUM_IMPL_FAST, &fs_info->flags);
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);
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, sb);
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);
}
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 goup 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, crc32c=%s%s\n", crc32c_impl(), 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();
}
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");