Google Git
Sign in
android-kvm / linux / fe95f58320e6c8dcea3bcb01336b9a7fdd7f684b / . / fs / btrfs / super.c
blob: 98fa0f382480a2a51420d586b1e2a2fa6c58d025 [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 <linux/security.h>
#include <linux/fs_parser.h>
#include <linux/swap.h>
#include "messages.h"
#include "delayed-inode.h"
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "direct-io.h"
#include "props.h"
#include "xattr.h"
#include "bio.h"
#include "export.h"
#include "compression.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;
static struct file_system_type btrfs_fs_type;
static void btrfs_put_super(struct super_block *sb)
{
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
btrfs_info(fs_info, "last unmount of filesystem %pU", fs_info->fs_devices->fsid);
close_ctree(fs_info);
}
/* Store the mount options related information. */
struct btrfs_fs_context {
char *subvol_name;
u64 subvol_objectid;
u64 max_inline;
u32 commit_interval;
u32 metadata_ratio;
u32 thread_pool_size;
unsigned long long mount_opt;
unsigned long compress_type:4;
unsigned int compress_level;
refcount_t refs;
};
enum {
Opt_acl,
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_max_inline,
Opt_barrier,
Opt_datacow,
Opt_datasum,
Opt_defrag,
Opt_discard,
Opt_discard_mode,
Opt_ratio,
Opt_rescan_uuid_tree,
Opt_skip_balance,
Opt_space_cache,
Opt_space_cache_version,
Opt_ssd,
Opt_ssd_spread,
Opt_subvol,
Opt_subvol_empty,
Opt_subvolid,
Opt_thread_pool,
Opt_treelog,
Opt_user_subvol_rm_allowed,
Opt_norecovery,
/* Rescue options */
Opt_rescue,
Opt_usebackuproot,
Opt_nologreplay,
/* Debugging options */
Opt_enospc_debug,
#ifdef CONFIG_BTRFS_DEBUG
Opt_fragment, Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
#endif
#ifdef CONFIG_BTRFS_FS_REF_VERIFY
Opt_ref_verify,
#endif
Opt_err,
};
enum {
Opt_fatal_errors_panic,
Opt_fatal_errors_bug,
};
static const struct constant_table btrfs_parameter_fatal_errors[] = {
{ "panic", Opt_fatal_errors_panic },
{ "bug", Opt_fatal_errors_bug },
{}
};
enum {
Opt_discard_sync,
Opt_discard_async,
};
static const struct constant_table btrfs_parameter_discard[] = {
{ "sync", Opt_discard_sync },
{ "async", Opt_discard_async },
{}
};
enum {
Opt_space_cache_v1,
Opt_space_cache_v2,
};
static const struct constant_table btrfs_parameter_space_cache[] = {
{ "v1", Opt_space_cache_v1 },
{ "v2", Opt_space_cache_v2 },
{}
};
enum {
Opt_rescue_usebackuproot,
Opt_rescue_nologreplay,
Opt_rescue_ignorebadroots,
Opt_rescue_ignoredatacsums,
Opt_rescue_ignoremetacsums,
Opt_rescue_ignoresuperflags,
Opt_rescue_parameter_all,
};
static const struct constant_table btrfs_parameter_rescue[] = {
{ "usebackuproot", Opt_rescue_usebackuproot },
{ "nologreplay", Opt_rescue_nologreplay },
{ "ignorebadroots", Opt_rescue_ignorebadroots },
{ "ibadroots", Opt_rescue_ignorebadroots },
{ "ignoredatacsums", Opt_rescue_ignoredatacsums },
{ "ignoremetacsums", Opt_rescue_ignoremetacsums},
{ "ignoresuperflags", Opt_rescue_ignoresuperflags},
{ "idatacsums", Opt_rescue_ignoredatacsums },
{ "imetacsums", Opt_rescue_ignoremetacsums},
{ "isuperflags", Opt_rescue_ignoresuperflags},
{ "all", Opt_rescue_parameter_all },
{}
};
#ifdef CONFIG_BTRFS_DEBUG
enum {
Opt_fragment_parameter_data,
Opt_fragment_parameter_metadata,
Opt_fragment_parameter_all,
};
static const struct constant_table btrfs_parameter_fragment[] = {
{ "data", Opt_fragment_parameter_data },
{ "metadata", Opt_fragment_parameter_metadata },
{ "all", Opt_fragment_parameter_all },
{}
};
#endif
static const struct fs_parameter_spec btrfs_fs_parameters[] = {
fsparam_flag_no("acl", Opt_acl),
fsparam_flag_no("autodefrag", Opt_defrag),
fsparam_flag_no("barrier", Opt_barrier),
fsparam_flag("clear_cache", Opt_clear_cache),
fsparam_u32("commit", Opt_commit_interval),
fsparam_flag("compress", Opt_compress),
fsparam_string("compress", Opt_compress_type),
fsparam_flag("compress-force", Opt_compress_force),
fsparam_string("compress-force", Opt_compress_force_type),
fsparam_flag_no("datacow", Opt_datacow),
fsparam_flag_no("datasum", Opt_datasum),
fsparam_flag("degraded", Opt_degraded),
fsparam_string("device", Opt_device),
fsparam_flag_no("discard", Opt_discard),
fsparam_enum("discard", Opt_discard_mode, btrfs_parameter_discard),
fsparam_enum("fatal_errors", Opt_fatal_errors, btrfs_parameter_fatal_errors),
fsparam_flag_no("flushoncommit", Opt_flushoncommit),
fsparam_string("max_inline", Opt_max_inline),
fsparam_u32("metadata_ratio", Opt_ratio),
fsparam_flag("rescan_uuid_tree", Opt_rescan_uuid_tree),
fsparam_flag("skip_balance", Opt_skip_balance),
fsparam_flag_no("space_cache", Opt_space_cache),
fsparam_enum("space_cache", Opt_space_cache_version, btrfs_parameter_space_cache),
fsparam_flag_no("ssd", Opt_ssd),
fsparam_flag_no("ssd_spread", Opt_ssd_spread),
fsparam_string("subvol", Opt_subvol),
fsparam_flag("subvol=", Opt_subvol_empty),
fsparam_u64("subvolid", Opt_subvolid),
fsparam_u32("thread_pool", Opt_thread_pool),
fsparam_flag_no("treelog", Opt_treelog),
fsparam_flag("user_subvol_rm_allowed", Opt_user_subvol_rm_allowed),
/* Rescue options. */
fsparam_enum("rescue", Opt_rescue, btrfs_parameter_rescue),
/* Deprecated, with alias rescue=nologreplay */
__fsparam(NULL, "nologreplay", Opt_nologreplay, fs_param_deprecated, NULL),
/* Deprecated, with alias rescue=usebackuproot */
__fsparam(NULL, "usebackuproot", Opt_usebackuproot, fs_param_deprecated, NULL),
/* For compatibility only, alias for "rescue=nologreplay". */
fsparam_flag("norecovery", Opt_norecovery),
/* Debugging options. */
fsparam_flag_no("enospc_debug", Opt_enospc_debug),
#ifdef CONFIG_BTRFS_DEBUG
fsparam_enum("fragment", Opt_fragment, btrfs_parameter_fragment),
#endif
#ifdef CONFIG_BTRFS_FS_REF_VERIFY
fsparam_flag("ref_verify", Opt_ref_verify),
#endif
{}
};
/* No support for restricting writes to btrfs devices yet... */
static inline blk_mode_t btrfs_open_mode(struct fs_context *fc)
{
return sb_open_mode(fc->sb_flags) & ~BLK_OPEN_RESTRICT_WRITES;
}
static int btrfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct btrfs_fs_context *ctx = fc->fs_private;
struct fs_parse_result result;
int opt;
opt = fs_parse(fc, btrfs_fs_parameters, param, &result);
if (opt < 0)
return opt;
switch (opt) {
case Opt_degraded:
btrfs_set_opt(ctx->mount_opt, DEGRADED);
break;
case Opt_subvol_empty:
/*
* This exists because we used to allow it on accident, so we're
* keeping it to maintain ABI. See 37becec95ac3 ("Btrfs: allow
* empty subvol= again").
*/
break;
case Opt_subvol:
kfree(ctx->subvol_name);
ctx->subvol_name = kstrdup(param->string, GFP_KERNEL);
if (!ctx->subvol_name)
return -ENOMEM;
break;
case Opt_subvolid:
ctx->subvol_objectid = result.uint_64;
/* subvolid=0 means give me the original fs_tree. */
if (!ctx->subvol_objectid)
ctx->subvol_objectid = BTRFS_FS_TREE_OBJECTID;
break;
case Opt_device: {
struct btrfs_device *device;
blk_mode_t mode = btrfs_open_mode(fc);
mutex_lock(&uuid_mutex);
device = btrfs_scan_one_device(param->string, mode, false);
mutex_unlock(&uuid_mutex);
if (IS_ERR(device))
return PTR_ERR(device);
break;
}
case Opt_datasum:
if (result.negated) {
btrfs_set_opt(ctx->mount_opt, NODATASUM);
} else {
btrfs_clear_opt(ctx->mount_opt, NODATACOW);
btrfs_clear_opt(ctx->mount_opt, NODATASUM);
}
break;
case Opt_datacow:
if (result.negated) {
btrfs_clear_opt(ctx->mount_opt, COMPRESS);
btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
btrfs_set_opt(ctx->mount_opt, NODATACOW);
btrfs_set_opt(ctx->mount_opt, NODATASUM);
} else {
btrfs_clear_opt(ctx->mount_opt, NODATACOW);
}
break;
case Opt_compress_force:
case Opt_compress_force_type:
btrfs_set_opt(ctx->mount_opt, FORCE_COMPRESS);
fallthrough;
case Opt_compress:
case Opt_compress_type:
if (opt == Opt_compress || opt == Opt_compress_force) {
ctx->compress_type = BTRFS_COMPRESS_ZLIB;
ctx->compress_level = BTRFS_ZLIB_DEFAULT_LEVEL;
btrfs_set_opt(ctx->mount_opt, COMPRESS);
btrfs_clear_opt(ctx->mount_opt, NODATACOW);
btrfs_clear_opt(ctx->mount_opt, NODATASUM);
} else if (strncmp(param->string, "zlib", 4) == 0) {
ctx->compress_type = BTRFS_COMPRESS_ZLIB;
ctx->compress_level =
btrfs_compress_str2level(BTRFS_COMPRESS_ZLIB,
param->string + 4);
btrfs_set_opt(ctx->mount_opt, COMPRESS);
btrfs_clear_opt(ctx->mount_opt, NODATACOW);
btrfs_clear_opt(ctx->mount_opt, NODATASUM);
} else if (strncmp(param->string, "lzo", 3) == 0) {
ctx->compress_type = BTRFS_COMPRESS_LZO;
ctx->compress_level = 0;
btrfs_set_opt(ctx->mount_opt, COMPRESS);
btrfs_clear_opt(ctx->mount_opt, NODATACOW);
btrfs_clear_opt(ctx->mount_opt, NODATASUM);
} else if (strncmp(param->string, "zstd", 4) == 0) {
ctx->compress_type = BTRFS_COMPRESS_ZSTD;
ctx->compress_level =
btrfs_compress_str2level(BTRFS_COMPRESS_ZSTD,
param->string + 4);
btrfs_set_opt(ctx->mount_opt, COMPRESS);
btrfs_clear_opt(ctx->mount_opt, NODATACOW);
btrfs_clear_opt(ctx->mount_opt, NODATASUM);
} else if (strncmp(param->string, "no", 2) == 0) {
ctx->compress_level = 0;
ctx->compress_type = 0;
btrfs_clear_opt(ctx->mount_opt, COMPRESS);
btrfs_clear_opt(ctx->mount_opt, FORCE_COMPRESS);
} else {
btrfs_err(NULL, "unrecognized compression value %s",
param->string);
return -EINVAL;
}
break;
case Opt_ssd:
if (result.negated) {
btrfs_set_opt(ctx->mount_opt, NOSSD);
btrfs_clear_opt(ctx->mount_opt, SSD);
btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD);
} else {
btrfs_set_opt(ctx->mount_opt, SSD);
btrfs_clear_opt(ctx->mount_opt, NOSSD);
}
break;
case Opt_ssd_spread:
if (result.negated) {
btrfs_clear_opt(ctx->mount_opt, SSD_SPREAD);
} else {
btrfs_set_opt(ctx->mount_opt, SSD);
btrfs_set_opt(ctx->mount_opt, SSD_SPREAD);
btrfs_clear_opt(ctx->mount_opt, NOSSD);
}
break;
case Opt_barrier:
if (result.negated)
btrfs_set_opt(ctx->mount_opt, NOBARRIER);
else
btrfs_clear_opt(ctx->mount_opt, NOBARRIER);
break;
case Opt_thread_pool:
if (result.uint_32 == 0) {
btrfs_err(NULL, "invalid value 0 for thread_pool");
return -EINVAL;
}
ctx->thread_pool_size = result.uint_32;
break;
case Opt_max_inline:
ctx->max_inline = memparse(param->string, NULL);
break;
case Opt_acl:
if (result.negated) {
fc->sb_flags &= ~SB_POSIXACL;
} else {
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
fc->sb_flags |= SB_POSIXACL;
#else
btrfs_err(NULL, "support for ACL not compiled in");
return -EINVAL;
#endif
}
/*
* VFS limits the ability to toggle ACL on and off via remount,
* despite every file system allowing this. This seems to be
* an oversight since we all do, but it'll fail if we're
* remounting. So don't set the mask here, we'll check it in
* btrfs_reconfigure and do the toggling ourselves.
*/
if (fc->purpose != FS_CONTEXT_FOR_RECONFIGURE)
fc->sb_flags_mask |= SB_POSIXACL;
break;
case Opt_treelog:
if (result.negated)
btrfs_set_opt(ctx->mount_opt, NOTREELOG);
else
btrfs_clear_opt(ctx->mount_opt, NOTREELOG);
break;
case Opt_nologreplay:
btrfs_warn(NULL,
"'nologreplay' is deprecated, use 'rescue=nologreplay' instead");
btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
break;
case Opt_norecovery:
btrfs_info(NULL,
"'norecovery' is for compatibility only, recommended to use 'rescue=nologreplay'");
btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
break;
case Opt_flushoncommit:
if (result.negated)
btrfs_clear_opt(ctx->mount_opt, FLUSHONCOMMIT);
else
btrfs_set_opt(ctx->mount_opt, FLUSHONCOMMIT);
break;
case Opt_ratio:
ctx->metadata_ratio = result.uint_32;
break;
case Opt_discard:
if (result.negated) {
btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC);
btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
btrfs_set_opt(ctx->mount_opt, NODISCARD);
} else {
btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC);
btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
}
break;
case Opt_discard_mode:
switch (result.uint_32) {
case Opt_discard_sync:
btrfs_clear_opt(ctx->mount_opt, DISCARD_ASYNC);
btrfs_set_opt(ctx->mount_opt, DISCARD_SYNC);
break;
case Opt_discard_async:
btrfs_clear_opt(ctx->mount_opt, DISCARD_SYNC);
btrfs_set_opt(ctx->mount_opt, DISCARD_ASYNC);
break;
default:
btrfs_err(NULL, "unrecognized discard mode value %s",
param->key);
return -EINVAL;
}
btrfs_clear_opt(ctx->mount_opt, NODISCARD);
break;
case Opt_space_cache:
if (result.negated) {
btrfs_set_opt(ctx->mount_opt, NOSPACECACHE);
btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE);
btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
} else {
btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
btrfs_set_opt(ctx->mount_opt, SPACE_CACHE);
}
break;
case Opt_space_cache_version:
switch (result.uint_32) {
case Opt_space_cache_v1:
btrfs_set_opt(ctx->mount_opt, SPACE_CACHE);
btrfs_clear_opt(ctx->mount_opt, FREE_SPACE_TREE);
break;
case Opt_space_cache_v2:
btrfs_clear_opt(ctx->mount_opt, SPACE_CACHE);
btrfs_set_opt(ctx->mount_opt, FREE_SPACE_TREE);
break;
default:
btrfs_err(NULL, "unrecognized space_cache value %s",
param->key);
return -EINVAL;
}
break;
case Opt_rescan_uuid_tree:
btrfs_set_opt(ctx->mount_opt, RESCAN_UUID_TREE);
break;
case Opt_clear_cache:
btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE);
break;
case Opt_user_subvol_rm_allowed:
btrfs_set_opt(ctx->mount_opt, USER_SUBVOL_RM_ALLOWED);
break;
case Opt_enospc_debug:
if (result.negated)
btrfs_clear_opt(ctx->mount_opt, ENOSPC_DEBUG);
else
btrfs_set_opt(ctx->mount_opt, ENOSPC_DEBUG);
break;
case Opt_defrag:
if (result.negated)
btrfs_clear_opt(ctx->mount_opt, AUTO_DEFRAG);
else
btrfs_set_opt(ctx->mount_opt, AUTO_DEFRAG);
break;
case Opt_usebackuproot:
btrfs_warn(NULL,
"'usebackuproot' is deprecated, use 'rescue=usebackuproot' instead");
btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT);
/* If we're loading the backup roots we can't trust the space cache. */
btrfs_set_opt(ctx->mount_opt, CLEAR_CACHE);
break;
case Opt_skip_balance:
btrfs_set_opt(ctx->mount_opt, SKIP_BALANCE);
break;
case Opt_fatal_errors:
switch (result.uint_32) {
case Opt_fatal_errors_panic:
btrfs_set_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR);
break;
case Opt_fatal_errors_bug:
btrfs_clear_opt(ctx->mount_opt, PANIC_ON_FATAL_ERROR);
break;
default:
btrfs_err(NULL, "unrecognized fatal_errors value %s",
param->key);
return -EINVAL;
}
break;
case Opt_commit_interval:
ctx->commit_interval = result.uint_32;
if (ctx->commit_interval == 0)
ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
break;
case Opt_rescue:
switch (result.uint_32) {
case Opt_rescue_usebackuproot:
btrfs_set_opt(ctx->mount_opt, USEBACKUPROOT);
break;
case Opt_rescue_nologreplay:
btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
break;
case Opt_rescue_ignorebadroots:
btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS);
break;
case Opt_rescue_ignoredatacsums:
btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS);
break;
case Opt_rescue_ignoremetacsums:
btrfs_set_opt(ctx->mount_opt, IGNOREMETACSUMS);
break;
case Opt_rescue_ignoresuperflags:
btrfs_set_opt(ctx->mount_opt, IGNORESUPERFLAGS);
break;
case Opt_rescue_parameter_all:
btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS);
btrfs_set_opt(ctx->mount_opt, IGNOREMETACSUMS);
btrfs_set_opt(ctx->mount_opt, IGNORESUPERFLAGS);
btrfs_set_opt(ctx->mount_opt, IGNOREBADROOTS);
btrfs_set_opt(ctx->mount_opt, NOLOGREPLAY);
break;
default:
btrfs_info(NULL, "unrecognized rescue option '%s'",
param->key);
return -EINVAL;
}
break;
#ifdef CONFIG_BTRFS_DEBUG
case Opt_fragment:
switch (result.uint_32) {
case Opt_fragment_parameter_all:
btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA);
btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA);
break;
case Opt_fragment_parameter_metadata:
btrfs_set_opt(ctx->mount_opt, FRAGMENT_METADATA);
break;
case Opt_fragment_parameter_data:
btrfs_set_opt(ctx->mount_opt, FRAGMENT_DATA);
break;
default:
btrfs_info(NULL, "unrecognized fragment option '%s'",
param->key);
return -EINVAL;
}
break;
#endif
#ifdef CONFIG_BTRFS_FS_REF_VERIFY
case Opt_ref_verify:
btrfs_set_opt(ctx->mount_opt, REF_VERIFY);
break;
#endif
default:
btrfs_err(NULL, "unrecognized mount option '%s'", param->key);
return -EINVAL;
}
return 0;
}
/*
* Some options only have meaning at mount time and shouldn't persist across
* remounts, or be displayed. Clear these at the end of mount and remount code
* paths.
*/
static void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info)
{
btrfs_clear_opt(fs_info->mount_opt, USEBACKUPROOT);
btrfs_clear_opt(fs_info->mount_opt, CLEAR_CACHE);
btrfs_clear_opt(fs_info->mount_opt, NOSPACECACHE);
}
static bool check_ro_option(const struct btrfs_fs_info *fs_info,
unsigned long long mount_opt, unsigned long long opt,
const char *opt_name)
{
if (mount_opt & opt) {
btrfs_err(fs_info, "%s must be used with ro mount option",
opt_name);
return true;
}
return false;
}
bool btrfs_check_options(const struct btrfs_fs_info *info,
unsigned long long *mount_opt,
unsigned long flags)
{
bool ret = true;
if (!(flags & SB_RDONLY) &&
(check_ro_option(info, *mount_opt, BTRFS_MOUNT_NOLOGREPLAY, "nologreplay") ||
check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREBADROOTS, "ignorebadroots") ||
check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREDATACSUMS, "ignoredatacsums") ||
check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNOREMETACSUMS, "ignoremetacsums") ||
check_ro_option(info, *mount_opt, BTRFS_MOUNT_IGNORESUPERFLAGS, "ignoresuperflags")))
ret = false;
if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE) &&
!btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE) &&
!btrfs_raw_test_opt(*mount_opt, CLEAR_CACHE)) {
btrfs_err(info, "cannot disable free-space-tree");
ret = false;
}
if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) &&
!btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE)) {
btrfs_err(info, "cannot disable free-space-tree with block-group-tree feature");
ret = false;
}
if (btrfs_check_mountopts_zoned(info, mount_opt))
ret = false;
if (!test_bit(BTRFS_FS_STATE_REMOUNTING, &info->fs_state)) {
if (btrfs_raw_test_opt(*mount_opt, SPACE_CACHE)) {
btrfs_info(info, "disk space caching is enabled");
btrfs_warn(info,
"space cache v1 is being deprecated and will be removed in a future release, please use -o space_cache=v2");
}
if (btrfs_raw_test_opt(*mount_opt, FREE_SPACE_TREE))
btrfs_info(info, "using free-space-tree");
}
return ret;
}
/*
* This is subtle, we only call this during open_ctree(). We need to pre-load
* the mount options with the on-disk settings. Before the new mount API took
* effect we would do this on mount and remount. With the new mount API we'll
* only do this on the initial mount.
*
* This isn't a change in behavior, because we're using the current state of the
* file system to set the current mount options. If you mounted with special
* options to disable these features and then remounted we wouldn't revert the
* settings, because mounting without these features cleared the on-disk
* settings, so this being called on re-mount is not needed.
*/
void btrfs_set_free_space_cache_settings(struct btrfs_fs_info *fs_info)
{
if (fs_info->sectorsize < PAGE_SIZE) {
btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
if (!btrfs_test_opt(fs_info, FREE_SPACE_TREE)) {
btrfs_info(fs_info,
"forcing free space tree for sector size %u with page size %lu",
fs_info->sectorsize, PAGE_SIZE);
btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
}
}
/*
* At this point our mount options are populated, so we only mess with
* these settings if we don't have any settings already.
*/
if (btrfs_test_opt(fs_info, FREE_SPACE_TREE))
return;
if (btrfs_is_zoned(fs_info) &&
btrfs_free_space_cache_v1_active(fs_info)) {
btrfs_info(fs_info, "zoned: clearing existing space cache");
btrfs_set_super_cache_generation(fs_info->super_copy, 0);
return;
}
if (btrfs_test_opt(fs_info, SPACE_CACHE))
return;
if (btrfs_test_opt(fs_info, NOSPACECACHE))
return;
/*
* At this point we don't have explicit options set by the user, set
* them ourselves based on the state of the file system.
*/
if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);
else if (btrfs_free_space_cache_v1_active(fs_info))
btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);
}
static void set_device_specific_options(struct btrfs_fs_info *fs_info)
{
if (!btrfs_test_opt(fs_info, NOSSD) &&
!fs_info->fs_devices->rotating)
btrfs_set_opt(fs_info->mount_opt, SSD);
/*
* For devices supporting discard turn on discard=async automatically,
* unless it's already set or disabled. This could be turned off by
* nodiscard for the same mount.
*
* The zoned mode piggy backs on the discard functionality for
* resetting a zone. There is no reason to delay the zone reset as it is
* fast enough. So, do not enable async discard for zoned mode.
*/
if (!(btrfs_test_opt(fs_info, DISCARD_SYNC) ||
btrfs_test_opt(fs_info, DISCARD_ASYNC) ||
btrfs_test_opt(fs_info, NODISCARD)) &&
fs_info->fs_devices->discardable &&
!btrfs_is_zoned(fs_info))
btrfs_set_opt(fs_info->mount_opt, DISCARD_ASYNC);
}
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;
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(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, NULL);
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, IGNOREMETACSUMS))
print_rescue_option(seq, "ignoremetacsums", &printed);
if (btrfs_test_opt(info, IGNORESUPERFLAGS))
print_rescue_option(seq, "ignoresuperflags", &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");
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_root_id(BTRFS_I(d_inode(dentry))->root));
subvol_name = btrfs_get_subvol_name_from_objectid(info,
btrfs_root_id(BTRFS_I(d_inode(dentry))->root));
if (!IS_ERR(subvol_name)) {
seq_puts(seq, ",subvol=");
seq_escape(seq, subvol_name, " \t\n\\");
kfree(subvol_name);
}
return 0;
}
/*
* 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_root_id(BTRFS_I(root_inode)->root);
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;
}
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->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 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 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_rw(struct btrfs_fs_info *fs_info)
{
int ret;
if (BTRFS_FS_ERROR(fs_info)) {
btrfs_err(fs_info,
"remounting read-write after error is not allowed");
return -EINVAL;
}
if (fs_info->fs_devices->rw_devices == 0)
return -EACCES;
if (!btrfs_check_rw_degradable(fs_info, NULL)) {
btrfs_warn(fs_info,
"too many missing devices, writable remount is not allowed");
return -EACCES;
}
if (btrfs_super_log_root(fs_info->super_copy) != 0) {
btrfs_warn(fs_info,
"mount required to replay tree-log, cannot remount read-write");
return -EINVAL;
}
/*
* 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)
return ret;
btrfs_clear_sb_rdonly(fs_info->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);
return 0;
}
static int btrfs_remount_ro(struct btrfs_fs_info *fs_info)
{
/*
* 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(fs_info->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);
return btrfs_commit_super(fs_info);
}
static void btrfs_ctx_to_info(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx)
{
fs_info->max_inline = ctx->max_inline;
fs_info->commit_interval = ctx->commit_interval;
fs_info->metadata_ratio = ctx->metadata_ratio;
fs_info->thread_pool_size = ctx->thread_pool_size;
fs_info->mount_opt = ctx->mount_opt;
fs_info->compress_type = ctx->compress_type;
fs_info->compress_level = ctx->compress_level;
}
static void btrfs_info_to_ctx(struct btrfs_fs_info *fs_info, struct btrfs_fs_context *ctx)
{
ctx->max_inline = fs_info->max_inline;
ctx->commit_interval = fs_info->commit_interval;
ctx->metadata_ratio = fs_info->metadata_ratio;
ctx->thread_pool_size = fs_info->thread_pool_size;
ctx->mount_opt = fs_info->mount_opt;
ctx->compress_type = fs_info->compress_type;
ctx->compress_level = fs_info->compress_level;
}
#define btrfs_info_if_set(fs_info, old_ctx, opt, fmt, args...) \
do { \
if ((!old_ctx || !btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \
btrfs_raw_test_opt(fs_info->mount_opt, opt)) \
btrfs_info(fs_info, fmt, ##args); \
} while (0)
#define btrfs_info_if_unset(fs_info, old_ctx, opt, fmt, args...) \
do { \
if ((old_ctx && btrfs_raw_test_opt(old_ctx->mount_opt, opt)) && \
!btrfs_raw_test_opt(fs_info->mount_opt, opt)) \
btrfs_info(fs_info, fmt, ##args); \
} while (0)
static void btrfs_emit_options(struct btrfs_fs_info *info,
struct btrfs_fs_context *old)
{
btrfs_info_if_set(info, old, NODATASUM, "setting nodatasum");
btrfs_info_if_set(info, old, DEGRADED, "allowing degraded mounts");
btrfs_info_if_set(info, old, NODATASUM, "setting nodatasum");
btrfs_info_if_set(info, old, SSD, "enabling ssd optimizations");
btrfs_info_if_set(info, old, SSD_SPREAD, "using spread ssd allocation scheme");
btrfs_info_if_set(info, old, NOBARRIER, "turning off barriers");
btrfs_info_if_set(info, old, NOTREELOG, "disabling tree log");
btrfs_info_if_set(info, old, NOLOGREPLAY, "disabling log replay at mount time");
btrfs_info_if_set(info, old, FLUSHONCOMMIT, "turning on flush-on-commit");
btrfs_info_if_set(info, old, DISCARD_SYNC, "turning on sync discard");
btrfs_info_if_set(info, old, DISCARD_ASYNC, "turning on async discard");
btrfs_info_if_set(info, old, FREE_SPACE_TREE, "enabling free space tree");
btrfs_info_if_set(info, old, SPACE_CACHE, "enabling disk space caching");
btrfs_info_if_set(info, old, CLEAR_CACHE, "force clearing of disk cache");
btrfs_info_if_set(info, old, AUTO_DEFRAG, "enabling auto defrag");
btrfs_info_if_set(info, old, FRAGMENT_DATA, "fragmenting data");
btrfs_info_if_set(info, old, FRAGMENT_METADATA, "fragmenting metadata");
btrfs_info_if_set(info, old, REF_VERIFY, "doing ref verification");
btrfs_info_if_set(info, old, USEBACKUPROOT, "trying to use backup root at mount time");
btrfs_info_if_set(info, old, IGNOREBADROOTS, "ignoring bad roots");
btrfs_info_if_set(info, old, IGNOREDATACSUMS, "ignoring data csums");
btrfs_info_if_set(info, old, IGNOREMETACSUMS, "ignoring meta csums");
btrfs_info_if_set(info, old, IGNORESUPERFLAGS, "ignoring unknown super block flags");
btrfs_info_if_unset(info, old, NODATACOW, "setting datacow");
btrfs_info_if_unset(info, old, SSD, "not using ssd optimizations");
btrfs_info_if_unset(info, old, SSD_SPREAD, "not using spread ssd allocation scheme");
btrfs_info_if_unset(info, old, NOBARRIER, "turning off barriers");
btrfs_info_if_unset(info, old, NOTREELOG, "enabling tree log");
btrfs_info_if_unset(info, old, SPACE_CACHE, "disabling disk space caching");
btrfs_info_if_unset(info, old, FREE_SPACE_TREE, "disabling free space tree");
btrfs_info_if_unset(info, old, AUTO_DEFRAG, "disabling auto defrag");
btrfs_info_if_unset(info, old, COMPRESS, "use no compression");
/* Did the compression settings change? */
if (btrfs_test_opt(info, COMPRESS) &&
(!old ||
old->compress_type != info->compress_type ||
old->compress_level != info->compress_level ||
(!btrfs_raw_test_opt(old->mount_opt, FORCE_COMPRESS) &&
btrfs_raw_test_opt(info->mount_opt, FORCE_COMPRESS)))) {
const char *compress_type = btrfs_compress_type2str(info->compress_type);
btrfs_info(info, "%s %s compression, level %d",
btrfs_test_opt(info, FORCE_COMPRESS) ? "force" : "use",
compress_type, info->compress_level);
}
if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
btrfs_info(info, "max_inline set to %llu", info->max_inline);
}
static int btrfs_reconfigure(struct fs_context *fc)
{
struct super_block *sb = fc->root->d_sb;
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
struct btrfs_fs_context *ctx = fc->fs_private;
struct btrfs_fs_context old_ctx;
int ret = 0;
bool mount_reconfigure = (fc->s_fs_info != NULL);
btrfs_info_to_ctx(fs_info, &old_ctx);
/*
* This is our "bind mount" trick, we don't want to allow the user to do
* anything other than mount a different ro/rw and a different subvol,
* all of the mount options should be maintained.
*/
if (mount_reconfigure)
ctx->mount_opt = old_ctx.mount_opt;
sync_filesystem(sb);
set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
if (!mount_reconfigure &&
!btrfs_check_options(fs_info, &ctx->mount_opt, fc->sb_flags))
return -EINVAL;
ret = btrfs_check_features(fs_info, !(fc->sb_flags & SB_RDONLY));
if (ret < 0)
return ret;
btrfs_ctx_to_info(fs_info, ctx);
btrfs_remount_begin(fs_info, old_ctx.mount_opt, fc->sb_flags);
btrfs_resize_thread_pool(fs_info, fs_info->thread_pool_size,
old_ctx.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) || (fc->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);
}
}
ret = 0;
if (!sb_rdonly(sb) && (fc->sb_flags & SB_RDONLY))
ret = btrfs_remount_ro(fs_info);
else if (sb_rdonly(sb) && !(fc->sb_flags & SB_RDONLY))
ret = btrfs_remount_rw(fs_info);
if (ret)
goto restore;
/*
* If we set the mask during the parameter parsing VFS would reject the
* remount. Here we can set the mask and the value will be updated
* appropriately.
*/
if ((fc->sb_flags & SB_POSIXACL) != (sb->s_flags & SB_POSIXACL))
fc->sb_flags_mask |= SB_POSIXACL;
btrfs_emit_options(fs_info, &old_ctx);
wake_up_process(fs_info->transaction_kthread);
btrfs_remount_cleanup(fs_info, old_ctx.mount_opt);
btrfs_clear_oneshot_options(fs_info);
clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
return 0;
restore:
btrfs_ctx_to_info(fs_info, &old_ctx);
btrfs_remount_cleanup(fs_info, old_ctx.mount_opt);
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 || total_free_meta - thresh < block_rsv->size))
buf->f_bavail = 0;
buf->f_type = BTRFS_SUPER_MAGIC;
buf->f_bsize = fs_info->sectorsize;
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_root_id(BTRFS_I(d_inode(dentry))->root) >> 32;
buf->f_fsid.val[1] ^= btrfs_root_id(BTRFS_I(d_inode(dentry))->root);
return 0;
}
static int btrfs_fc_test_super(struct super_block *sb, struct fs_context *fc)
{
struct btrfs_fs_info *p = fc->s_fs_info;
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
return fs_info->fs_devices == p->fs_devices;
}
static int btrfs_get_tree_super(struct fs_context *fc)
{
struct btrfs_fs_info *fs_info = fc->s_fs_info;
struct btrfs_fs_context *ctx = fc->fs_private;
struct btrfs_fs_devices *fs_devices = NULL;
struct block_device *bdev;
struct btrfs_device *device;
struct super_block *sb;
blk_mode_t mode = btrfs_open_mode(fc);
int ret;
btrfs_ctx_to_info(fs_info, ctx);
mutex_lock(&uuid_mutex);
/*
* With 'true' passed to btrfs_scan_one_device() (mount time) we expect
* either a valid device or an error.
*/
device = btrfs_scan_one_device(fc->source, mode, true);
ASSERT(device != NULL);
if (IS_ERR(device)) {
mutex_unlock(&uuid_mutex);
return PTR_ERR(device);
}
fs_devices = device->fs_devices;
fs_info->fs_devices = fs_devices;
ret = btrfs_open_devices(fs_devices, mode, &btrfs_fs_type);
mutex_unlock(&uuid_mutex);
if (ret)
return ret;
if (!(fc->sb_flags & SB_RDONLY) && fs_devices->rw_devices == 0) {
ret = -EACCES;
goto error;
}
bdev = fs_devices->latest_dev->bdev;
/*
* From now on the error handling is not straightforward.
*
* If successful, this will transfer the fs_info into the super block,
* and fc->s_fs_info will be NULL. However if there's an existing
* super, we'll still have fc->s_fs_info populated. If we error
* completely out it'll be cleaned up when we drop the fs_context,
* otherwise it's tied to the lifetime of the super_block.
*/
sb = sget_fc(fc, btrfs_fc_test_super, set_anon_super_fc);
if (IS_ERR(sb)) {
ret = PTR_ERR(sb);
goto error;
}
set_device_specific_options(fs_info);
if (sb->s_root) {
btrfs_close_devices(fs_devices);
if ((fc->sb_flags ^ sb->s_flags) & SB_RDONLY)
ret = -EBUSY;
} else {
snprintf(sb->s_id, sizeof(sb->s_id), "%pg", bdev);
shrinker_debugfs_rename(sb->s_shrink, "sb-btrfs:%s", sb->s_id);
btrfs_sb(sb)->bdev_holder = &btrfs_fs_type;
ret = btrfs_fill_super(sb, fs_devices, NULL);
}
if (ret) {
deactivate_locked_super(sb);
return ret;
}
btrfs_clear_oneshot_options(fs_info);
fc->root = dget(sb->s_root);
return 0;
error:
btrfs_close_devices(fs_devices);
return ret;
}
/*
* Ever since commit 0723a0473fb4 ("btrfs: allow mounting btrfs subvolumes
* with different ro/rw options") the following works:
*
* (i) mount /dev/sda3 -o subvol=foo,ro /mnt/foo
* (ii) mount /dev/sda3 -o subvol=bar,rw /mnt/bar
*
* which looks nice and innocent but is actually pretty intricate and deserves
* a long comment.
*
* On another filesystem a subvolume mount is close to something like:
*
* (iii) # create rw superblock + initial mount
* mount -t xfs /dev/sdb /opt/
*
* # create ro bind mount
* mount --bind -o ro /opt/foo /mnt/foo
*
* # unmount initial mount
* umount /opt
*
* Of course, there's some special subvolume sauce and there's the fact that the
* sb->s_root dentry is really swapped after mount_subtree(). But conceptually
* it's very close and will help us understand the issue.
*
* The old mount API didn't cleanly distinguish between a mount being made ro
* and a superblock being made ro. The only way to change the ro state of
* either object was by passing ms_rdonly. If a new mount was created via
* mount(2) such as:
*
* mount("/dev/sdb", "/mnt", "xfs", ms_rdonly, null);
*
* the MS_RDONLY flag being specified had two effects:
*
* (1) MNT_READONLY was raised -> the resulting mount got
* @mnt->mnt_flags |= MNT_READONLY raised.
*
* (2) MS_RDONLY was passed to the filesystem's mount method and the filesystems
* made the superblock ro. Note, how SB_RDONLY has the same value as
* ms_rdonly and is raised whenever MS_RDONLY is passed through mount(2).
*
* Creating a subtree mount via (iii) ends up leaving a rw superblock with a
* subtree mounted ro.
*
* But consider the effect on the old mount API on btrfs subvolume mounting
* which combines the distinct step in (iii) into a single step.
*
* By issuing (i) both the mount and the superblock are turned ro. Now when (ii)
* is issued the superblock is ro and thus even if the mount created for (ii) is
* rw it wouldn't help. Hence, btrfs needed to transition the superblock from ro
* to rw for (ii) which it did using an internal remount call.
*
* IOW, subvolume mounting was inherently complicated due to the ambiguity of
* MS_RDONLY in mount(2). Note, this ambiguity has mount(8) always translate
* "ro" to MS_RDONLY. IOW, in both (i) and (ii) "ro" becomes MS_RDONLY when
* passed by mount(8) to mount(2).
*
* Enter the new mount API. The new mount API disambiguates making a mount ro
* and making a superblock ro.
*
* (3) To turn a mount ro the MOUNT_ATTR_ONLY flag can be used with either
* fsmount() or mount_setattr() this is a pure VFS level change for a
* specific mount or mount tree that is never seen by the filesystem itself.
*
* (4) To turn a superblock ro the "ro" flag must be used with
* fsconfig(FSCONFIG_SET_FLAG, "ro"). This option is seen by the filesystem
* in fc->sb_flags.
*
* This disambiguation has rather positive consequences. Mounting a subvolume
* ro will not also turn the superblock ro. Only the mount for the subvolume
* will become ro.
*
* So, if the superblock creation request comes from the new mount API the
* caller must have explicitly done:
*
* fsconfig(FSCONFIG_SET_FLAG, "ro")
* fsmount/mount_setattr(MOUNT_ATTR_RDONLY)
*
* IOW, at some point the caller must have explicitly turned the whole
* superblock ro and we shouldn't just undo it like we did for the old mount
* API. In any case, it lets us avoid the hack in the new mount API.
*
* Consequently, the remounting hack must only be used for requests originating
* from the old mount API and should be marked for full deprecation so it can be
* turned off in a couple of years.
*
* The new mount API has no reason to support this hack.
*/
static struct vfsmount *btrfs_reconfigure_for_mount(struct fs_context *fc)
{
struct vfsmount *mnt;
int ret;
const bool ro2rw = !(fc->sb_flags & SB_RDONLY);
/*
* We got an EBUSY because our SB_RDONLY flag didn't match the existing
* super block, so invert our setting here and retry the mount so we
* can get our vfsmount.
*/
if (ro2rw)
fc->sb_flags |= SB_RDONLY;
else
fc->sb_flags &= ~SB_RDONLY;
mnt = fc_mount(fc);
if (IS_ERR(mnt))
return mnt;
if (!fc->oldapi || !ro2rw)
return mnt;
/* We need to convert to rw, call reconfigure. */
fc->sb_flags &= ~SB_RDONLY;
down_write(&mnt->mnt_sb->s_umount);
ret = btrfs_reconfigure(fc);
up_write(&mnt->mnt_sb->s_umount);
if (ret) {
mntput(mnt);
return ERR_PTR(ret);
}
return mnt;
}
static int btrfs_get_tree_subvol(struct fs_context *fc)
{
struct btrfs_fs_info *fs_info = NULL;
struct btrfs_fs_context *ctx = fc->fs_private;
struct fs_context *dup_fc;
struct dentry *dentry;
struct vfsmount *mnt;
/*
* 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)
return -ENOMEM;
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) {
btrfs_free_fs_info(fs_info);
return -ENOMEM;
}
btrfs_init_fs_info(fs_info);
dup_fc = vfs_dup_fs_context(fc);
if (IS_ERR(dup_fc)) {
btrfs_free_fs_info(fs_info);
return PTR_ERR(dup_fc);
}
/*
* When we do the sget_fc this gets transferred to the sb, so we only
* need to set it on the dup_fc as this is what creates the super block.
*/
dup_fc->s_fs_info = fs_info;
/*
* We'll do the security settings in our btrfs_get_tree_super() mount
* loop, they were duplicated into dup_fc, we can drop the originals
* here.
*/
security_free_mnt_opts(&fc->security);
fc->security = NULL;
mnt = fc_mount(dup_fc);
if (PTR_ERR_OR_ZERO(mnt) == -EBUSY)
mnt = btrfs_reconfigure_for_mount(dup_fc);
put_fs_context(dup_fc);
if (IS_ERR(mnt))
return PTR_ERR(mnt);
/*
* This free's ->subvol_name, because if it isn't set we have to
* allocate a buffer to hold the subvol_name, so we just drop our
* reference to it here.
*/
dentry = mount_subvol(ctx->subvol_name, ctx->subvol_objectid, mnt);
ctx->subvol_name = NULL;
if (IS_ERR(dentry))
return PTR_ERR(dentry);
fc->root = dentry;
return 0;
}
static int btrfs_get_tree(struct fs_context *fc)
{
/*
* Since we use mount_subtree to mount the default/specified subvol, we
* have to do mounts in two steps.
*
* First pass through we call btrfs_get_tree_subvol(), this is just a
* wrapper around fc_mount() to call back into here again, and this time
* we'll call btrfs_get_tree_super(). This will do the open_ctree() and
* everything to open the devices and file system. Then we return back
* with a fully constructed vfsmount in btrfs_get_tree_subvol(), and
* from there we can do our mount_subvol() call, which will lookup
* whichever subvol we're mounting and setup this fc with the
* appropriate dentry for the subvol.
*/
if (fc->s_fs_info)
return btrfs_get_tree_super(fc);
return btrfs_get_tree_subvol(fc);
}
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 void btrfs_free_fs_context(struct fs_context *fc)
{
struct btrfs_fs_context *ctx = fc->fs_private;
struct btrfs_fs_info *fs_info = fc->s_fs_info;
if (fs_info)
btrfs_free_fs_info(fs_info);
if (ctx && refcount_dec_and_test(&ctx->refs)) {
kfree(ctx->subvol_name);
kfree(ctx);
}
}
static int btrfs_dup_fs_context(struct fs_context *fc, struct fs_context *src_fc)
{
struct btrfs_fs_context *ctx = src_fc->fs_private;
/*
* Give a ref to our ctx to this dup, as we want to keep it around for
* our original fc so we can have the subvolume name or objectid.
*
* We unset ->source in the original fc because the dup needs it for
* mounting, and then once we free the dup it'll free ->source, so we
* need to make sure we're only pointing to it in one fc.
*/
refcount_inc(&ctx->refs);
fc->fs_private = ctx;
fc->source = src_fc->source;
src_fc->source = NULL;
return 0;
}
static const struct fs_context_operations btrfs_fs_context_ops = {
.parse_param = btrfs_parse_param,
.reconfigure = btrfs_reconfigure,
.get_tree = btrfs_get_tree,
.dup = btrfs_dup_fs_context,
.free = btrfs_free_fs_context,
};
static int btrfs_init_fs_context(struct fs_context *fc)
{
struct btrfs_fs_context *ctx;
ctx = kzalloc(sizeof(struct btrfs_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
refcount_set(&ctx->refs, 1);
fc->fs_private = ctx;
fc->ops = &btrfs_fs_context_ops;
if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
btrfs_info_to_ctx(btrfs_sb(fc->root->d_sb), ctx);
} else {
ctx->thread_pool_size =
min_t(unsigned long, num_online_cpus() + 2, 8);
ctx->max_inline = BTRFS_DEFAULT_MAX_INLINE;
ctx->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
}
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
fc->sb_flags |= SB_POSIXACL;
#endif
fc->sb_flags |= SB_I_VERSION;
return 0;
}
static struct file_system_type btrfs_fs_type = {
.owner = THIS_MODULE,
.name = "btrfs",
.init_fs_context = btrfs_init_fs_context,
.parameters = btrfs_fs_parameters,
.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);
ret = btrfs_check_ioctl_vol_args_path(vol);
if (ret < 0)
goto out;
switch (cmd) {
case BTRFS_IOC_SCAN_DEV:
mutex_lock(&uuid_mutex);
/*
* Scanning outside of mount can return NULL which would turn
* into 0 error code.
*/
device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false);
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);
/*
* Scanning outside of mount can return NULL which would turn
* into 0 error code.
*/
device = btrfs_scan_one_device(vol->name, BLK_OPEN_READ, false);
if (IS_ERR_OR_NULL(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;
}
out:
kfree(vol);
return ret;
}
static int btrfs_freeze(struct super_block *sb)
{
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
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.
*/
return btrfs_commit_current_transaction(fs_info->tree_root);
}
static int check_dev_super(struct btrfs_device *dev)
{
struct btrfs_fs_info *fs_info = dev->fs_info;
struct btrfs_super_block *sb;
u64 last_trans;
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;
last_trans = btrfs_get_last_trans_committed(fs_info);
if (btrfs_super_generation(sb) != last_trans) {
btrfs_err(fs_info, "transid mismatch, has %llu expect %llu",
btrfs_super_generation(sb), last_trans);
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 long btrfs_nr_cached_objects(struct super_block *sb, struct shrink_control *sc)
{
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
const s64 nr = percpu_counter_sum_positive(&fs_info->evictable_extent_maps);
trace_btrfs_extent_map_shrinker_count(fs_info, nr);
/*
* Only report the real number for DEBUG builds, as there are reports of
* serious performance degradation caused by too frequent shrinks.
*/
if (IS_ENABLED(CONFIG_BTRFS_DEBUG))
return nr;
return 0;
}
static long btrfs_free_cached_objects(struct super_block *sb, struct shrink_control *sc)
{
const long nr_to_scan = min_t(unsigned long, LONG_MAX, sc->nr_to_scan);
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
/*
* We may be called from any task trying to allocate memory and we don't
* want to slow it down with scanning and dropping extent maps. It would
* also cause heavy lock contention if many tasks concurrently enter
* here. Therefore only allow kswapd tasks to scan and drop extent maps.
*/
if (!current_is_kswapd())
return 0;
return btrfs_free_extent_maps(fs_info, nr_to_scan);
}
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,
.freeze_fs = btrfs_freeze,
.unfreeze_fs = btrfs_unfreeze,
.nr_cached_objects = btrfs_nr_cached_objects,
.free_cached_objects = btrfs_free_cached_objects,
};
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_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_init_dio,
.exit_func = btrfs_destroy_dio,
}, {
.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_DESCRIPTION("B-Tree File System (BTRFS)");
MODULE_LICENSE("GPL");
MODULE_SOFTDEP("pre: crc32c");
MODULE_SOFTDEP("pre: xxhash64");
MODULE_SOFTDEP("pre: sha256");
MODULE_SOFTDEP("pre: blake2b-256");