btrfs: track exclusive filesystem operation in flags
There are several operations, usually started from ioctls, that cannot run concurrently. The status is tracked in mutually_exclusive_operation_running as an atomic_t. We can easily track the status as one of the per-filesystem flag bits with same synchronization guarantees. The conversion replaces: * atomic_xchg(..., 1) -> test_and_set_bit(FLAG, ...) * atomic_set(..., 0) -> clear_bit(FLAG, ...) Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
parent
48a89bc4f2
commit
171938e528
4 changed files with 25 additions and 26 deletions
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@ -705,6 +705,11 @@ struct btrfs_delayed_root;
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#define BTRFS_FS_BTREE_ERR 11
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#define BTRFS_FS_LOG1_ERR 12
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#define BTRFS_FS_LOG2_ERR 13
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/*
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* Indicate that a whole-filesystem exclusive operation is running
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* (device replace, resize, device add/delete, balance)
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*/
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#define BTRFS_FS_EXCL_OP 14
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struct btrfs_fs_info {
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u8 fsid[BTRFS_FSID_SIZE];
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@ -1070,8 +1075,6 @@ struct btrfs_fs_info {
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/* device replace state */
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struct btrfs_dev_replace dev_replace;
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atomic_t mutually_exclusive_operation_running;
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struct percpu_counter bio_counter;
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wait_queue_head_t replace_wait;
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@ -784,8 +784,7 @@ int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info)
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}
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btrfs_dev_replace_unlock(dev_replace, 1);
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WARN_ON(atomic_xchg(
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&fs_info->mutually_exclusive_operation_running, 1));
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WARN_ON(test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags));
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task = kthread_run(btrfs_dev_replace_kthread, fs_info, "btrfs-devrepl");
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return PTR_ERR_OR_ZERO(task);
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}
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@ -814,7 +813,7 @@ static int btrfs_dev_replace_kthread(void *data)
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(unsigned int)progress);
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}
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btrfs_dev_replace_continue_on_mount(fs_info);
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atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
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clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
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return 0;
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}
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@ -1504,7 +1504,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
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if (ret)
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return ret;
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if (atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1)) {
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if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
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mnt_drop_write_file(file);
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return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
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}
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@ -1619,7 +1619,7 @@ out_free:
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kfree(vol_args);
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out:
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mutex_unlock(&fs_info->volume_mutex);
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atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
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clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
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mnt_drop_write_file(file);
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return ret;
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}
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@ -2661,7 +2661,7 @@ static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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if (atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1))
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if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags))
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return BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
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mutex_lock(&fs_info->volume_mutex);
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@ -2680,7 +2680,7 @@ static long btrfs_ioctl_add_dev(struct btrfs_fs_info *fs_info, void __user *arg)
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kfree(vol_args);
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out:
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mutex_unlock(&fs_info->volume_mutex);
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atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
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clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
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return ret;
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}
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@ -2708,7 +2708,7 @@ static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
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if (vol_args->flags & ~BTRFS_VOL_ARG_V2_FLAGS_SUPPORTED)
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return -EOPNOTSUPP;
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if (atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1)) {
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if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
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ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
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goto out;
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}
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@ -2721,7 +2721,7 @@ static long btrfs_ioctl_rm_dev_v2(struct file *file, void __user *arg)
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ret = btrfs_rm_device(fs_info, vol_args->name, 0);
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}
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mutex_unlock(&fs_info->volume_mutex);
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atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
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clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
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if (!ret) {
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if (vol_args->flags & BTRFS_DEVICE_SPEC_BY_ID)
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@ -2752,7 +2752,7 @@ static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
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if (ret)
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return ret;
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if (atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1)) {
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if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
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ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
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goto out_drop_write;
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}
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@ -2772,7 +2772,7 @@ static long btrfs_ioctl_rm_dev(struct file *file, void __user *arg)
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btrfs_info(fs_info, "disk deleted %s", vol_args->name);
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kfree(vol_args);
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out:
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atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
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clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
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out_drop_write:
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mnt_drop_write_file(file);
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@ -4442,13 +4442,11 @@ static long btrfs_ioctl_dev_replace(struct btrfs_fs_info *fs_info,
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ret = -EROFS;
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goto out;
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}
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if (atomic_xchg(
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&fs_info->mutually_exclusive_operation_running, 1)) {
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if (test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
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ret = BTRFS_ERROR_DEV_EXCL_RUN_IN_PROGRESS;
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} else {
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ret = btrfs_dev_replace_by_ioctl(fs_info, p);
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atomic_set(
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&fs_info->mutually_exclusive_operation_running, 0);
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clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
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}
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break;
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case BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS:
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@ -4643,7 +4641,7 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
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return ret;
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again:
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if (!atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1)) {
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if (!test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags)) {
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mutex_lock(&fs_info->volume_mutex);
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mutex_lock(&fs_info->balance_mutex);
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need_unlock = true;
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@ -4689,7 +4687,7 @@ again:
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}
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locked:
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BUG_ON(!atomic_read(&fs_info->mutually_exclusive_operation_running));
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BUG_ON(!test_bit(BTRFS_FS_EXCL_OP, &fs_info->flags));
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if (arg) {
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bargs = memdup_user(arg, sizeof(*bargs));
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@ -4745,11 +4743,10 @@ locked:
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do_balance:
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/*
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* Ownership of bctl and mutually_exclusive_operation_running
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* Ownership of bctl and filesystem flag BTRFS_FS_EXCL_OP
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* goes to to btrfs_balance. bctl is freed in __cancel_balance,
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* or, if restriper was paused all the way until unmount, in
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* free_fs_info. mutually_exclusive_operation_running is
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* cleared in __cancel_balance.
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* free_fs_info. The flag is cleared in __cancel_balance.
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*/
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need_unlock = false;
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@ -4769,7 +4766,7 @@ out_unlock:
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mutex_unlock(&fs_info->balance_mutex);
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mutex_unlock(&fs_info->volume_mutex);
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if (need_unlock)
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atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
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clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
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out:
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mnt_drop_write_file(file);
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return ret;
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@ -3761,7 +3761,7 @@ static void __cancel_balance(struct btrfs_fs_info *fs_info)
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if (ret)
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btrfs_handle_fs_error(fs_info, ret, NULL);
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atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
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clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
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}
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/* Non-zero return value signifies invalidity */
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@ -3941,7 +3941,7 @@ out:
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__cancel_balance(fs_info);
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else {
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kfree(bctl);
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atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
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clear_bit(BTRFS_FS_EXCL_OP, &fs_info->flags);
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}
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return ret;
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}
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@ -4031,7 +4031,7 @@ int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
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btrfs_balance_sys(leaf, item, &disk_bargs);
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btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
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WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
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WARN_ON(test_and_set_bit(BTRFS_FS_EXCL_OP, &fs_info->flags));
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mutex_lock(&fs_info->volume_mutex);
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mutex_lock(&fs_info->balance_mutex);
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