[PATCH v3 1/8] introduce __sb_writers_{acquired,release}() helpers

Oleg Nesterov
2015-08-14T17:22:10Z

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>
Reviewed-by: Jan Kara <jack@suse.com>
---
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_writers_acquired(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_writers_release(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_writers_release(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_writers_acquired(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_writers_acquired(sb, lev) \
+ rwsem_acquire_read(&(sb)->s_writers.lock_map[(lev)-1], 0, 1, _THIS_IP_)
+#define __sb_writers_release(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