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| author | David Sterba <dsterba@suse.com> | 2018-03-21 03:31:04 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2018-05-28 19:07:25 +0300 |
| commit | 3009a62f3b18230a000d1a91e9a676036487e834 (patch) | |
| tree | 87182c14f50c753c4b408b103c7bdc2215ac84c3 /fs/btrfs/volumes.c | |
| parent | dccdb07bc996e9c8de80d06813163ca08288bf73 (diff) | |
| download | linux-3009a62f3b18230a000d1a91e9a676036487e834.tar.xz | |
btrfs: track running balance in a simpler way
Currently fs_info::balance_running is 0 or 1 and does not use the
semantics of atomics. The pause and cancel check for 0, that can happen
only after __btrfs_balance exits for whatever reason.
Parallel calls to balance ioctl may enter btrfs_ioctl_balance multiple
times but will block on the balance_mutex that protects the
fs_info::flags bit.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/volumes.c')
| -rw-r--r-- | fs/btrfs/volumes.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 0216bc86f476..ed230247ae5d 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -3907,13 +3907,14 @@ int btrfs_balance(struct btrfs_balance_control *bctl, spin_unlock(&fs_info->balance_lock); } - atomic_inc(&fs_info->balance_running); + ASSERT(!test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)); + set_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags); mutex_unlock(&fs_info->balance_mutex); ret = __btrfs_balance(fs_info); mutex_lock(&fs_info->balance_mutex); - atomic_dec(&fs_info->balance_running); + clear_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags); if (bargs) { memset(bargs, 0, sizeof(*bargs)); @@ -4061,16 +4062,16 @@ int btrfs_pause_balance(struct btrfs_fs_info *fs_info) return -ENOTCONN; } - if (atomic_read(&fs_info->balance_running)) { + if (test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) { atomic_inc(&fs_info->balance_pause_req); mutex_unlock(&fs_info->balance_mutex); wait_event(fs_info->balance_wait_q, - atomic_read(&fs_info->balance_running) == 0); + !test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)); mutex_lock(&fs_info->balance_mutex); /* we are good with balance_ctl ripped off from under us */ - BUG_ON(atomic_read(&fs_info->balance_running)); + BUG_ON(test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)); atomic_dec(&fs_info->balance_pause_req); } else { ret = -ENOTCONN; @@ -4096,10 +4097,10 @@ int btrfs_cancel_balance(struct btrfs_fs_info *fs_info) * if we are running just wait and return, balance item is * deleted in btrfs_balance in this case */ - if (atomic_read(&fs_info->balance_running)) { + if (test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)) { mutex_unlock(&fs_info->balance_mutex); wait_event(fs_info->balance_wait_q, - atomic_read(&fs_info->balance_running) == 0); + !test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)); mutex_lock(&fs_info->balance_mutex); } else { mutex_unlock(&fs_info->balance_mutex); @@ -4115,7 +4116,8 @@ int btrfs_cancel_balance(struct btrfs_fs_info *fs_info) } } - BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running)); + BUG_ON(fs_info->balance_ctl || + test_bit(BTRFS_FS_BALANCE_RUNNING, &fs_info->flags)); atomic_dec(&fs_info->balance_cancel_req); mutex_unlock(&fs_info->balance_mutex); return 0; |