Re: [PATCH v2 1/8] introduce __sb_{acquire,release}_write() helpers

Jan Kara
2015-08-13T09:46:00Z

On Tue 11-08-15 19:03:58, Oleg Nesterov wrote:
> Preparation to hide the sb->s_writers internals from xfs and btrfs.
> Add 2 trivial define's they can use rather than play with ->s_writers
> directly. No changes in btrfs/transaction.o and xfs/xfs_aops.o.
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Looks good. You can add:

Reviewed-by: Jan Kara <jack@suse.com>

Honza

> ---
> fs/btrfs/transaction.c | 8 ++------
> fs/xfs/xfs_aops.c | 6 ++----
> include/linux/fs.h | 5 +++++
> 3 files changed, 9 insertions(+), 10 deletions(-)
>
> diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
> index 5628e25..6dca4e9 100644
> --- a/fs/btrfs/transaction.c
> +++ b/fs/btrfs/transaction.c
> @@ -1620,9 +1620,7 @@ static void do_async_commit(struct work_struct *work)
> * Tell lockdep about it.
> */
> if (ac->newtrans->type & __TRANS_FREEZABLE)
> - rwsem_acquire_read(
> - &ac->root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
> - 0, 1, _THIS_IP_);
> + __sb_acquire_write(ac->root->fs_info->sb, SB_FREEZE_FS);
>
> current->journal_info = ac->newtrans;
>
> @@ -1661,9 +1659,7 @@ int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
> * async commit thread will be the one to unlock it.
> */
> if (ac->newtrans->type & __TRANS_FREEZABLE)
> - rwsem_release(
> - &root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
> - 1, _THIS_IP_);
> + __sb_release_write(root->fs_info->sb, SB_FREEZE_FS);
>
> schedule_work(&ac->work);
>
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index a56960d..8034c78 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -119,8 +119,7 @@ xfs_setfilesize_trans_alloc(
> * We may pass freeze protection with a transaction. So tell lockdep
> * we released it.
> */
> - rwsem_release(&ioend->io_inode->i_sb->s_writers.lock_map[SB_FREEZE_FS-1],
> - 1, _THIS_IP_);
> + __sb_release_write(ioend->io_inode->i_sb, SB_FREEZE_FS);
> /*
> * We hand off the transaction to the completion thread now, so
> * clear the flag here.
> @@ -171,8 +170,7 @@ xfs_setfilesize_ioend(
> * Similarly for freeze protection.
> */
> current_set_flags_nested(&tp->t_pflags, PF_FSTRANS);
> - rwsem_acquire_read(&VFS_I(ip)->i_sb->s_writers.lock_map[SB_FREEZE_FS-1],
> - 0, 1, _THIS_IP_);
> + __sb_acquire_write(VFS_I(ip)->i_sb, SB_FREEZE_FS);
>
> return xfs_setfilesize(ip, tp, ioend->io_offset, ioend->io_size);
> }
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 35ec87e..78ac768 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1362,6 +1362,11 @@ extern struct timespec current_fs_time(struct super_block *sb);
> void __sb_end_write(struct super_block *sb, int level);
> int __sb_start_write(struct super_block *sb, int level, bool wait);
>
> +#define __sb_acquire_write(sb, lev) \
> + rwsem_acquire_read(&(sb)->s_writers.lock_map[(lev)-1], 0, 1, _THIS_IP_)
> +#define __sb_release_write(sb, lev) \
> + rwsem_release(&(sb)->s_writers.lock_map[(lev)-1], 1, _THIS_IP_)
> +
> /**
> * sb_end_write - drop write access to a superblock
> * @sb: the super we wrote to
> --
> 1.5.5.1
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR