From 9b011adfe14977fcda977234609d43ca52463a3d Mon Sep 17 00:00:00 2001 From: Wang Shilong Date: Fri, 25 Oct 2013 19:12:02 +0800 Subject: [PATCH] Btrfs: remove scrub_super_lock holding in btrfs_sync_log() Originally, we introduced scrub_super_lock to synchronize tree log code with scrubbing super. However we can replace scrub_super_lock with device_list_mutex, because writing super will hold this mutex, this will reduce an extra lock holding when writing supers in sync log code. Signed-off-by: Wang Shilong Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/ctree.h | 3 --- fs/btrfs/disk-io.c | 1 - fs/btrfs/scrub.c | 18 +++++------------- fs/btrfs/tree-log.c | 2 -- fs/btrfs/volumes.h | 4 +++- 5 files changed, 8 insertions(+), 20 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 9f5e1cfb0209..34279665fd69 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1586,7 +1586,6 @@ struct btrfs_fs_info { atomic_t scrubs_paused; atomic_t scrub_cancel_req; wait_queue_head_t scrub_pause_wait; - struct rw_semaphore scrub_super_lock; int scrub_workers_refcnt; struct btrfs_workers scrub_workers; struct btrfs_workers scrub_wr_completion_workers; @@ -3950,9 +3949,7 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, u64 end, struct btrfs_scrub_progress *progress, int readonly, int is_dev_replace); void btrfs_scrub_pause(struct btrfs_root *root); -void btrfs_scrub_pause_super(struct btrfs_root *root); void btrfs_scrub_continue(struct btrfs_root *root); -void btrfs_scrub_continue_super(struct btrfs_root *root); int btrfs_scrub_cancel(struct btrfs_fs_info *info); int btrfs_scrub_cancel_dev(struct btrfs_fs_info *info, struct btrfs_device *dev); diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 62c4aba221bb..a3ad3a27944d 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2250,7 +2250,6 @@ int open_ctree(struct super_block *sb, atomic_set(&fs_info->scrubs_paused, 0); atomic_set(&fs_info->scrub_cancel_req, 0); init_waitqueue_head(&fs_info->scrub_pause_wait); - init_rwsem(&fs_info->scrub_super_lock); fs_info->scrub_workers_refcnt = 0; #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY fs_info->check_integrity_print_mask = 0; diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index f21e2df89bc2..12009b4279ad 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -2932,13 +2932,15 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, atomic_inc(&fs_info->scrubs_running); mutex_unlock(&fs_info->scrub_lock); - mutex_unlock(&fs_info->fs_devices->device_list_mutex); if (!is_dev_replace) { - down_read(&fs_info->scrub_super_lock); + /* + * by holding device list mutex, we can + * kick off writing super in log tree sync. + */ ret = scrub_supers(sctx, dev); - up_read(&fs_info->scrub_super_lock); } + mutex_unlock(&fs_info->fs_devices->device_list_mutex); if (!ret) ret = scrub_enumerate_chunks(sctx, dev, start, end, @@ -2988,16 +2990,6 @@ void btrfs_scrub_continue(struct btrfs_root *root) wake_up(&fs_info->scrub_pause_wait); } -void btrfs_scrub_pause_super(struct btrfs_root *root) -{ - down_write(&root->fs_info->scrub_super_lock); -} - -void btrfs_scrub_continue_super(struct btrfs_root *root) -{ - up_write(&root->fs_info->scrub_super_lock); -} - int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info) { mutex_lock(&fs_info->scrub_lock); diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index f98002ed32b1..257cbae8c948 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -2586,9 +2586,7 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, * the running transaction open, so a full commit can't hop * in and cause problems either. */ - btrfs_scrub_pause_super(root); ret = write_ctree_super(trans, root->fs_info->tree_root, 1); - btrfs_scrub_continue_super(root); if (ret) { btrfs_abort_transaction(trans, root, ret); goto out_wake_log_root; diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index b72f540c8b29..49e0ff01143f 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -132,7 +132,9 @@ struct btrfs_fs_devices { /* all of the devices in the FS, protected by a mutex * so we can safely walk it to write out the supers without - * worrying about add/remove by the multi-device code + * worrying about add/remove by the multi-device code. + * Scrubbing super can kick off supers writing by holding + * this mutex lock. */ struct mutex device_list_mutex; struct list_head devices; -- 2.11.0