// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2007 Oracle. All rights reserved. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "messages.h" #include "delayed-inode.h" #include "ctree.h" #include "disk-io.h" #include "transaction.h" #include "btrfs_inode.h" #include "print-tree.h" #include "props.h" #include "xattr.h" #include "bio.h" #include "export.h" #include "compression.h" #include "rcu-string.h" #include "dev-replace.h" #include "free-space-cache.h" #include "backref.h" #include "space-info.h" #include "sysfs.h" #include "zoned.h" #include "tests/btrfs-tests.h" #include "block-group.h" #include "discard.h" #include "qgroup.h" #include "raid56.h" #include "fs.h" #include "accessors.h" #include "defrag.h" #include "dir-item.h" #include "ioctl.h" #include "scrub.h" #include "verity.h" #include "super.h" #include "extent-tree.h" #define CREATE_TRACE_POINTS #include 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 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, Opt_ignorebadroots, Opt_ignoredatacsums, Opt_rescue_all, /* 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_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 }, { "idatacsums", Opt_rescue_ignoredatacsums }, { "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_parameter_all: btrfs_set_opt(ctx->mount_opt, IGNOREDATACSUMS); 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(struct btrfs_fs_info *fs_info, unsigned long mount_opt, unsigned 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(struct btrfs_fs_info *info, unsigned 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"))) 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"); 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(sb, BTRFS_FIRST_FREE_OBJECTID, fs_info->fs_root); if (IS_ERR(inode)) { err = PTR_ERR(inode); btrfs_handle_fs_error(fs_info, err, NULL); goto fail_close; } sb->s_root = d_make_root(inode); if (!sb->s_root) { err = -ENOMEM; goto fail_close; } sb->s_flags |= SB_ACTIVE; return 0; fail_close: close_ctree(fs_info); return err; } int btrfs_sync_fs(struct super_block *sb, int wait) { struct btrfs_trans_handle *trans; struct btrfs_fs_info *fs_info = btrfs_sb(sb); struct btrfs_root *root = fs_info->tree_root; trace_btrfs_sync_fs(fs_info, wait); if (!wait) { filemap_flush(fs_info->btree_inode->i_mapping); return 0; } btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1); trans = btrfs_attach_transaction_barrier(root); if (IS_ERR(trans)) { /* no transaction, don't bother */ if (PTR_ERR(trans) == -ENOENT) { /* * Exit unless we have some pending changes * that need to go through commit */ if (!test_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags)) return 0; /* * A non-blocking test if the fs is frozen. We must not * start a new transaction here otherwise a deadlock * happens. The pending operations are delayed to the * next commit after thawing. */ if (sb_start_write_trylock(sb)) sb_end_write(sb); else return 0; trans = btrfs_start_transaction(root, 0); } if (IS_ERR(trans)) return PTR_ERR(trans); } return btrfs_commit_transaction(trans); } static void print_rescue_option(struct seq_file *seq, const char *s, bool *printed) { seq_printf(seq, "%s%s", (*printed) ? ":" : ",rescue=", s); *printed = true; } static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) { struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb); const char *compress_type; const char *subvol_name; bool printed = false; if (btrfs_test_opt(info, DEGRADED)) seq_puts(seq, ",degraded"); if (btrfs_test_opt(info, NODATASUM)) seq_puts(seq, ",nodatasum"); if (btrfs_test_opt(info, NODATACOW)) seq_puts(seq, ",nodatacow"); if (btrfs_test_opt(info, NOBARRIER)) seq_puts(seq, ",nobarrier"); if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE) seq_printf(seq, ",max_inline=%llu", info->max_inline); if (info->thread_pool_size != min_t(unsigned long, num_online_cpus() + 2, 8)) seq_printf(seq, ",thread_pool=%u", info->thread_pool_size); if (btrfs_test_opt(info, COMPRESS)) { compress_type = btrfs_compress_type2str(info->compress_type); if (btrfs_test_opt(info, FORCE_COMPRESS)) seq_printf(seq, ",compress-force=%s", compress_type); else seq_printf(seq, ",compress=%s", compress_type); if (info->compress_level) seq_printf(seq, ":%d", info->compress_level); } if (btrfs_test_opt(info, NOSSD)) seq_puts(seq, ",nossd"); if (btrfs_test_opt(info, SSD_SPREAD)) seq_puts(seq, ",ssd_spread"); else if (btrfs_test_opt(info, SSD)) seq_puts(seq, ",ssd"); if (btrfs_test_opt(info, NOTREELOG)) seq_puts(seq, ",notreelog"); if (btrfs_test_opt(info, NOLOGREPLAY)) print_rescue_option(seq, "nologreplay", &printed); if (btrfs_test_opt(info, USEBACKUPROOT)) print_rescue_option(seq, "usebackuproot", &printed); if (btrfs_test_opt(info, IGNOREBADROOTS)) print_rescue_option(seq, "ignorebadroots", &printed); if (btrfs_test_opt(info, IGNOREDATACSUMS)) print_rescue_option(seq, "ignoredatacsums", &printed); if (btrfs_test_opt(info, FLUSHONCOMMIT)) seq_puts(seq, ",flushoncommit"); if (btrfs_test_opt(info, DISCARD_SYNC)) seq_puts(seq, ",discard"); if (btrfs_test_opt(info, DISCARD_ASYNC)) seq_puts(seq, ",discard=async"); if (!(info->sb->s_flags & SB_POSIXACL)) seq_puts(seq, ",noacl"); if (btrfs_free_space_cache_v1_active(info)) seq_puts(seq, ",space_cache"); else if (btrfs_fs_compat_ro(info, FREE_SPACE_TREE)) seq_puts(seq, ",space_cache=v2"); else seq_puts(seq, ",nospace_cache"); if (btrfs_test_opt(info, RESCAN_UUID_TREE)) seq_puts(seq, ",rescan_uuid_tree"); if (btrfs_test_opt(info, CLEAR_CACHE)) seq_puts(seq, ",clear_cache"); if (btrfs_test_opt(info, USER_SUBVOL_RM_ALLOWED)) seq_puts(seq, ",user_subvol_rm_allowed"); if (btrfs_test_opt(info, ENOSPC_DEBUG)) seq_puts(seq, ",enospc_debug"); if (btrfs_test_opt(info, AUTO_DEFRAG)) seq_puts(seq, ",autodefrag"); if (btrfs_test_opt(info, SKIP_BALANCE)) seq_puts(seq, ",skip_balance"); 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; } /* * 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; } 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 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_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_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_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 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); vol->name[BTRFS_PATH_NAME_MAX] = '\0'; 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; } 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; 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 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, }; 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_transaction_init, .exit_func = btrfs_transaction_exit, }, { .init_func = btrfs_ctree_init, .exit_func = btrfs_ctree_exit, }, { .init_func = btrfs_free_space_init, .exit_func = btrfs_free_space_exit, }, { .init_func = extent_state_init_cachep, .exit_func = extent_state_free_cachep, }, { .init_func = extent_buffer_init_cachep, .exit_func = extent_buffer_free_cachep, }, { .init_func = btrfs_bioset_init, .exit_func = btrfs_bioset_exit, }, { .init_func = extent_map_init, .exit_func = extent_map_exit, }, { .init_func = ordered_data_init, .exit_func = ordered_data_exit, }, { .init_func = btrfs_delayed_inode_init, .exit_func = btrfs_delayed_inode_exit, }, { .init_func = btrfs_auto_defrag_init, .exit_func = btrfs_auto_defrag_exit, }, { .init_func = btrfs_delayed_ref_init, .exit_func = btrfs_delayed_ref_exit, }, { .init_func = btrfs_prelim_ref_init, .exit_func = btrfs_prelim_ref_exit, }, { .init_func = btrfs_interface_init, .exit_func = btrfs_interface_exit, }, { .init_func = btrfs_print_mod_info, .exit_func = NULL, }, { .init_func = btrfs_run_sanity_tests, .exit_func = NULL, }, { .init_func = register_btrfs, .exit_func = unregister_btrfs, } }; static bool mod_init_result[ARRAY_SIZE(mod_init_seq)]; static __always_inline void btrfs_exit_btrfs_fs(void) { int i; for (i = ARRAY_SIZE(mod_init_seq) - 1; i >= 0; i--) { if (!mod_init_result[i]) continue; if (mod_init_seq[i].exit_func) mod_init_seq[i].exit_func(); mod_init_result[i] = false; } } static void __exit exit_btrfs_fs(void) { btrfs_exit_btrfs_fs(); btrfs_cleanup_fs_uuids(); } static int __init init_btrfs_fs(void) { int ret; int i; for (i = 0; i < ARRAY_SIZE(mod_init_seq); i++) { ASSERT(!mod_init_result[i]); ret = mod_init_seq[i].init_func(); if (ret < 0) { btrfs_exit_btrfs_fs(); return ret; } mod_init_result[i] = true; } return 0; } late_initcall(init_btrfs_fs); module_exit(exit_btrfs_fs) MODULE_LICENSE("GPL"); MODULE_SOFTDEP("pre: crc32c"); MODULE_SOFTDEP("pre: xxhash64"); MODULE_SOFTDEP("pre: sha256"); MODULE_SOFTDEP("pre: blake2b-256");