From addc3fa74e5bcfabc0766f934a8895d1f9f6a67c Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Thu, 24 Jul 2014 11:37:11 +0800 Subject: [PATCH] Btrfs: Fix the problem that the dirty flag of dev stats is cleared The io error might happen during writing out the device stats, and the device stats information and dirty flag would be update at that time, but the current code didn't consider this case, just clear the dirty flag, it would cause that we forgot to write out the new device stats information. Fix it. Signed-off-by: Miao Xie Signed-off-by: Chris Mason --- fs/btrfs/volumes.c | 7 +++++-- fs/btrfs/volumes.h | 19 +++++++++++++++---- 2 files changed, 20 insertions(+), 6 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 7f25ff1c3854..e04424490f12 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -159,6 +159,7 @@ static struct btrfs_device *__alloc_device(void) spin_lock_init(&dev->reada_lock); atomic_set(&dev->reada_in_flight, 0); + atomic_set(&dev->dev_stats_ccnt, 0); INIT_RADIX_TREE(&dev->reada_zones, GFP_NOFS & ~__GFP_WAIT); INIT_RADIX_TREE(&dev->reada_extents, GFP_NOFS & ~__GFP_WAIT); @@ -6394,16 +6395,18 @@ int btrfs_run_dev_stats(struct btrfs_trans_handle *trans, struct btrfs_root *dev_root = fs_info->dev_root; struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; struct btrfs_device *device; + int stats_cnt; int ret = 0; mutex_lock(&fs_devices->device_list_mutex); list_for_each_entry(device, &fs_devices->devices, dev_list) { - if (!device->dev_stats_valid || !device->dev_stats_dirty) + if (!device->dev_stats_valid || !btrfs_dev_stats_dirty(device)) continue; + stats_cnt = atomic_read(&device->dev_stats_ccnt); ret = update_dev_stat_item(trans, dev_root, device); if (!ret) - device->dev_stats_dirty = 0; + atomic_sub(stats_cnt, &device->dev_stats_ccnt); } mutex_unlock(&fs_devices->device_list_mutex); diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 6fcc8eae7834..0defd232e290 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -110,7 +110,9 @@ struct btrfs_device { /* disk I/O failure stats. For detailed description refer to * enum btrfs_dev_stat_values in ioctl.h */ int dev_stats_valid; - int dev_stats_dirty; /* counters need to be written to disk */ + + /* Counter to record the change of device stats */ + atomic_t dev_stats_ccnt; atomic_t dev_stat_values[BTRFS_DEV_STAT_VALUES_MAX]; }; @@ -359,11 +361,18 @@ unsigned long btrfs_full_stripe_len(struct btrfs_root *root, int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans, struct btrfs_root *extent_root, u64 chunk_offset, u64 chunk_size); + +static inline int btrfs_dev_stats_dirty(struct btrfs_device *dev) +{ + return atomic_read(&dev->dev_stats_ccnt); +} + static inline void btrfs_dev_stat_inc(struct btrfs_device *dev, int index) { atomic_inc(dev->dev_stat_values + index); - dev->dev_stats_dirty = 1; + smp_mb__before_atomic(); + atomic_inc(&dev->dev_stats_ccnt); } static inline int btrfs_dev_stat_read(struct btrfs_device *dev, @@ -378,7 +387,8 @@ static inline int btrfs_dev_stat_read_and_reset(struct btrfs_device *dev, int ret; ret = atomic_xchg(dev->dev_stat_values + index, 0); - dev->dev_stats_dirty = 1; + smp_mb__before_atomic(); + atomic_inc(&dev->dev_stats_ccnt); return ret; } @@ -386,7 +396,8 @@ static inline void btrfs_dev_stat_set(struct btrfs_device *dev, int index, unsigned long val) { atomic_set(dev->dev_stat_values + index, val); - dev->dev_stats_dirty = 1; + smp_mb__before_atomic(); + atomic_inc(&dev->dev_stats_ccnt); } static inline void btrfs_dev_stat_reset(struct btrfs_device *dev, -- 2.45.2