From ff023aac31198e88507d626825379b28ea481d4d Mon Sep 17 00:00:00 2001 From: Stefan Behrens Date: Tue, 6 Nov 2012 11:43:11 +0100 Subject: Btrfs: add code to scrub to copy read data to another disk The device replace procedure makes use of the scrub code. The scrub code is the most efficient code to read the allocated data of a disk, i.e. it reads sequentially in order to avoid disk head movements, it skips unallocated blocks, it uses read ahead mechanisms, and it contains all the code to detect and repair defects. This commit adds code to scrub to allow the scrub code to copy read data to another disk. One goal is to be able to perform as fast as possible. Therefore the write requests are collected until huge bios are built, and the write process is decoupled from the read process with some kind of flow control, of course, in order to limit the allocated memory. The best performance on spinning disks could by reached when the head movements are avoided as much as possible. Therefore a single worker is used to interface the read process with the write process. The regular scrub operation works as fast as before, it is not negatively influenced and actually it is more or less unchanged. Signed-off-by: Stefan Behrens Signed-off-by: Chris Mason --- fs/btrfs/dev-replace.h | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 fs/btrfs/dev-replace.h (limited to 'fs/btrfs/dev-replace.h') diff --git a/fs/btrfs/dev-replace.h b/fs/btrfs/dev-replace.h new file mode 100644 index 000000000000..1fb5c89037ee --- /dev/null +++ b/fs/btrfs/dev-replace.h @@ -0,0 +1,26 @@ +/* + * Copyright (C) STRATO AG 2012. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public + * License v2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 021110-1307, USA. + */ + +#if !defined(__BTRFS_DEV_REPLACE__) +#define __BTRFS_DEV_REPLACE__ + +static inline void btrfs_dev_replace_stats_inc(atomic64_t *stat_value) +{ + atomic64_inc(stat_value); +} +#endif -- cgit v1.2.2 From e93c89c1aaaaaec3487c4c18dd02360371790722 Mon Sep 17 00:00:00 2001 From: Stefan Behrens Date: Mon, 5 Nov 2012 17:33:06 +0100 Subject: Btrfs: add new sources for device replace code This adds a new file to the sources together with the header file and the changes to ioctl.h and ctree.h that are required by the new C source file. Additionally, 4 new functions are added to volume.c that deal with device creation and destruction. Signed-off-by: Stefan Behrens Signed-off-by: Chris Mason --- fs/btrfs/dev-replace.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'fs/btrfs/dev-replace.h') diff --git a/fs/btrfs/dev-replace.h b/fs/btrfs/dev-replace.h index 1fb5c89037ee..20035cbbf021 100644 --- a/fs/btrfs/dev-replace.h +++ b/fs/btrfs/dev-replace.h @@ -19,6 +19,24 @@ #if !defined(__BTRFS_DEV_REPLACE__) #define __BTRFS_DEV_REPLACE__ +struct btrfs_ioctl_dev_replace_args; + +int btrfs_init_dev_replace(struct btrfs_fs_info *fs_info); +int btrfs_run_dev_replace(struct btrfs_trans_handle *trans, + struct btrfs_fs_info *fs_info); +void btrfs_after_dev_replace_commit(struct btrfs_fs_info *fs_info); +int btrfs_dev_replace_start(struct btrfs_root *root, + struct btrfs_ioctl_dev_replace_args *args); +void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info, + struct btrfs_ioctl_dev_replace_args *args); +int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info, + struct btrfs_ioctl_dev_replace_args *args); +void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info); +int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info); +int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace); +void btrfs_dev_replace_lock(struct btrfs_dev_replace *dev_replace); +void btrfs_dev_replace_unlock(struct btrfs_dev_replace *dev_replace); + static inline void btrfs_dev_replace_stats_inc(atomic64_t *stat_value) { atomic64_inc(stat_value); -- cgit v1.2.2