diff options
author | David Sterba <dsterba@suse.com> | 2016-02-26 15:38:32 +0100 |
---|---|---|
committer | David Sterba <dsterba@suse.com> | 2016-02-26 15:38:32 +0100 |
commit | 675d276b322b45e7bf7c616a2847bdc425745b99 (patch) | |
tree | c61e7108034bf1230024880ec8ae46a9617077c2 /fs/btrfs/dev-replace.c | |
parent | Merge branch 'foreign/josef/space-updates' into for-chris-4.6 (diff) | |
parent | Btrfs: fix lockdep deadlock warning due to dev_replace (diff) | |
download | linux-675d276b322b45e7bf7c616a2847bdc425745b99.tar.xz linux-675d276b322b45e7bf7c616a2847bdc425745b99.zip |
Merge branch 'foreign/liubo/replace-lockup' into for-chris-4.6
Diffstat (limited to 'fs/btrfs/dev-replace.c')
-rw-r--r-- | fs/btrfs/dev-replace.c | 130 |
1 files changed, 70 insertions, 60 deletions
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c index 01ce5fcecc5c..ff2db7a6c894 100644 --- a/fs/btrfs/dev-replace.c +++ b/fs/btrfs/dev-replace.c @@ -202,13 +202,13 @@ int btrfs_run_dev_replace(struct btrfs_trans_handle *trans, struct btrfs_dev_replace_item *ptr; struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; - btrfs_dev_replace_lock(dev_replace); + btrfs_dev_replace_lock(dev_replace, 0); if (!dev_replace->is_valid || !dev_replace->item_needs_writeback) { - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 0); return 0; } - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 0); key.objectid = 0; key.type = BTRFS_DEV_REPLACE_KEY; @@ -264,7 +264,7 @@ int btrfs_run_dev_replace(struct btrfs_trans_handle *trans, ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_replace_item); - btrfs_dev_replace_lock(dev_replace); + btrfs_dev_replace_lock(dev_replace, 1); if (dev_replace->srcdev) btrfs_set_dev_replace_src_devid(eb, ptr, dev_replace->srcdev->devid); @@ -287,7 +287,7 @@ int btrfs_run_dev_replace(struct btrfs_trans_handle *trans, btrfs_set_dev_replace_cursor_right(eb, ptr, dev_replace->cursor_right); dev_replace->item_needs_writeback = 0; - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 1); btrfs_mark_buffer_dirty(eb); @@ -356,7 +356,7 @@ int btrfs_dev_replace_start(struct btrfs_root *root, return PTR_ERR(trans); } - btrfs_dev_replace_lock(dev_replace); + btrfs_dev_replace_lock(dev_replace, 1); switch (dev_replace->replace_state) { case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED: case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED: @@ -395,7 +395,7 @@ int btrfs_dev_replace_start(struct btrfs_root *root, dev_replace->is_valid = 1; dev_replace->item_needs_writeback = 1; args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR; - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 1); ret = btrfs_sysfs_add_device_link(tgt_device->fs_devices, tgt_device); if (ret) @@ -407,7 +407,7 @@ int btrfs_dev_replace_start(struct btrfs_root *root, trans = btrfs_start_transaction(root, 0); if (IS_ERR(trans)) { ret = PTR_ERR(trans); - btrfs_dev_replace_lock(dev_replace); + btrfs_dev_replace_lock(dev_replace, 1); goto leave; } @@ -433,7 +433,7 @@ int btrfs_dev_replace_start(struct btrfs_root *root, leave: dev_replace->srcdev = NULL; dev_replace->tgtdev = NULL; - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 1); btrfs_destroy_dev_replace_tgtdev(fs_info, tgt_device); return ret; } @@ -471,18 +471,18 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, /* don't allow cancel or unmount to disturb the finishing procedure */ mutex_lock(&dev_replace->lock_finishing_cancel_unmount); - btrfs_dev_replace_lock(dev_replace); + btrfs_dev_replace_lock(dev_replace, 0); /* was the operation canceled, or is it finished? */ if (dev_replace->replace_state != BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED) { - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 0); mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); return 0; } tgt_device = dev_replace->tgtdev; src_device = dev_replace->srcdev; - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 0); /* * flush all outstanding I/O and inode extent mappings before the @@ -507,7 +507,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, /* keep away write_all_supers() during the finishing procedure */ mutex_lock(&root->fs_info->fs_devices->device_list_mutex); mutex_lock(&root->fs_info->chunk_mutex); - btrfs_dev_replace_lock(dev_replace); + btrfs_dev_replace_lock(dev_replace, 1); dev_replace->replace_state = scrub_ret ? BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED : BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED; @@ -528,7 +528,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, rcu_str_deref(src_device->name), src_device->devid, rcu_str_deref(tgt_device->name), scrub_ret); - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 1); mutex_unlock(&root->fs_info->chunk_mutex); mutex_unlock(&root->fs_info->fs_devices->device_list_mutex); mutex_unlock(&uuid_mutex); @@ -565,7 +565,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info, list_add(&tgt_device->dev_alloc_list, &fs_info->fs_devices->alloc_list); fs_info->fs_devices->rw_devices++; - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 1); btrfs_rm_dev_replace_blocked(fs_info); @@ -649,7 +649,7 @@ void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info, struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; struct btrfs_device *srcdev; - btrfs_dev_replace_lock(dev_replace); + btrfs_dev_replace_lock(dev_replace, 0); /* even if !dev_replace_is_valid, the values are good enough for * the replace_status ioctl */ args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR; @@ -675,7 +675,7 @@ void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info, div_u64(btrfs_device_get_total_bytes(srcdev), 1000)); break; } - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 0); } int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info, @@ -698,13 +698,13 @@ static u64 __btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info) return -EROFS; mutex_lock(&dev_replace->lock_finishing_cancel_unmount); - btrfs_dev_replace_lock(dev_replace); + btrfs_dev_replace_lock(dev_replace, 1); switch (dev_replace->replace_state) { case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED: case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED: case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED: result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED; - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 1); goto leave; case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED: case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED: @@ -717,7 +717,7 @@ static u64 __btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info) dev_replace->replace_state = BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED; dev_replace->time_stopped = get_seconds(); dev_replace->item_needs_writeback = 1; - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 1); btrfs_scrub_cancel(fs_info); trans = btrfs_start_transaction(root, 0); @@ -740,7 +740,7 @@ void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info) struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; mutex_lock(&dev_replace->lock_finishing_cancel_unmount); - btrfs_dev_replace_lock(dev_replace); + btrfs_dev_replace_lock(dev_replace, 1); switch (dev_replace->replace_state) { case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED: case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED: @@ -756,7 +756,7 @@ void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info) break; } - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 1); mutex_unlock(&dev_replace->lock_finishing_cancel_unmount); } @@ -766,12 +766,12 @@ int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info) struct task_struct *task; struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace; - btrfs_dev_replace_lock(dev_replace); + btrfs_dev_replace_lock(dev_replace, 1); switch (dev_replace->replace_state) { case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED: case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED: case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED: - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 1); return 0; case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED: break; @@ -784,10 +784,10 @@ int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info) btrfs_info(fs_info, "cannot continue dev_replace, tgtdev is missing"); btrfs_info(fs_info, "you may cancel the operation after 'mount -o degraded'"); - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 1); return 0; } - btrfs_dev_replace_unlock(dev_replace); + btrfs_dev_replace_unlock(dev_replace, 1); WARN_ON(atomic_xchg( &fs_info->mutually_exclusive_operation_running, 1)); @@ -865,48 +865,58 @@ int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace) return 1; } -void btrfs_dev_replace_lock(struct btrfs_dev_replace *dev_replace) +void btrfs_dev_replace_lock(struct btrfs_dev_replace *dev_replace, int rw) { - /* the beginning is just an optimization for the typical case */ - if (atomic_read(&dev_replace->nesting_level) == 0) { -acquire_lock: - /* this is not a nested case where the same thread - * is trying to acqurire the same lock twice */ - mutex_lock(&dev_replace->lock); - mutex_lock(&dev_replace->lock_management_lock); - dev_replace->lock_owner = current->pid; - atomic_inc(&dev_replace->nesting_level); - mutex_unlock(&dev_replace->lock_management_lock); - return; + if (rw == 1) { + /* write */ +again: + wait_event(dev_replace->read_lock_wq, + atomic_read(&dev_replace->blocking_readers) == 0); + write_lock(&dev_replace->lock); + if (atomic_read(&dev_replace->blocking_readers)) { + write_unlock(&dev_replace->lock); + goto again; + } + } else { + read_lock(&dev_replace->lock); + atomic_inc(&dev_replace->read_locks); } +} - mutex_lock(&dev_replace->lock_management_lock); - if (atomic_read(&dev_replace->nesting_level) > 0 && - dev_replace->lock_owner == current->pid) { - WARN_ON(!mutex_is_locked(&dev_replace->lock)); - atomic_inc(&dev_replace->nesting_level); - mutex_unlock(&dev_replace->lock_management_lock); - return; +void btrfs_dev_replace_unlock(struct btrfs_dev_replace *dev_replace, int rw) +{ + if (rw == 1) { + /* write */ + ASSERT(atomic_read(&dev_replace->blocking_readers) == 0); + write_unlock(&dev_replace->lock); + } else { + ASSERT(atomic_read(&dev_replace->read_locks) > 0); + atomic_dec(&dev_replace->read_locks); + read_unlock(&dev_replace->lock); } +} - mutex_unlock(&dev_replace->lock_management_lock); - goto acquire_lock; +/* inc blocking cnt and release read lock */ +void btrfs_dev_replace_set_lock_blocking( + struct btrfs_dev_replace *dev_replace) +{ + /* only set blocking for read lock */ + ASSERT(atomic_read(&dev_replace->read_locks) > 0); + atomic_inc(&dev_replace->blocking_readers); + read_unlock(&dev_replace->lock); } -void btrfs_dev_replace_unlock(struct btrfs_dev_replace *dev_replace) +/* acquire read lock and dec blocking cnt */ +void btrfs_dev_replace_clear_lock_blocking( + struct btrfs_dev_replace *dev_replace) { - WARN_ON(!mutex_is_locked(&dev_replace->lock)); - mutex_lock(&dev_replace->lock_management_lock); - WARN_ON(atomic_read(&dev_replace->nesting_level) < 1); - WARN_ON(dev_replace->lock_owner != current->pid); - atomic_dec(&dev_replace->nesting_level); - if (atomic_read(&dev_replace->nesting_level) == 0) { - dev_replace->lock_owner = 0; - mutex_unlock(&dev_replace->lock_management_lock); - mutex_unlock(&dev_replace->lock); - } else { - mutex_unlock(&dev_replace->lock_management_lock); - } + /* only set blocking for read lock */ + ASSERT(atomic_read(&dev_replace->read_locks) > 0); + ASSERT(atomic_read(&dev_replace->blocking_readers) > 0); + read_lock(&dev_replace->lock); + if (atomic_dec_and_test(&dev_replace->blocking_readers) && + waitqueue_active(&dev_replace->read_lock_wq)) + wake_up(&dev_replace->read_lock_wq); } void btrfs_bio_counter_inc_noblocked(struct btrfs_fs_info *fs_info) |