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Commit f0d07b7f authored by Jan Kara's avatar Jan Kara Committed by Fengguang Wu
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writeback: Remove wb->list_lock from writeback_single_inode() 



writeback_single_inode() doesn't need wb->list_lock for anything on entry now.
So remove the requirement. This makes locking of writeback_single_inode()
temporarily awkward (entering with i_lock, returning with i_lock and
wb->list_lock) but it will be sanitized in the next patch.

Also inode_wait_for_writeback() doesn't need wb->list_lock for anything. It was
just taking it to make usage convenient for callers but with
writeback_single_inode() changing it's not very convenient anymore. So remove
the lock from that function.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarFengguang Wu <fengguang.wu@intel.com>
parent ccb26b5a

fs/fs-writeback.c

+7 −10
Original line number Diff line number Diff line
@@ -328,8 +328,7 @@ static int write_inode(struct inode *inode, struct writeback_control *wbc) 
/*

 * Wait for writeback on an inode to complete.

 */

static void inode_wait_for_writeback(struct inode *inode,

				     struct bdi_writeback *wb)

static void inode_wait_for_writeback(struct inode *inode)

{

	DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC);

	wait_queue_head_t *wqh;
@@ -337,9 +336,7 @@ static void inode_wait_for_writeback(struct inode *inode, 
	wqh = bit_waitqueue(&inode->i_state, __I_SYNC);

	while (inode->i_state & I_SYNC) {

		spin_unlock(&inode->i_lock);

		spin_unlock(&wb->list_lock);

		__wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE);

		spin_lock(&wb->list_lock);

		spin_lock(&inode->i_lock);

	}

}
@@ -418,7 +415,6 @@ writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, 
	unsigned dirty;

	int ret;



	assert_spin_locked(&wb->list_lock);

	assert_spin_locked(&inode->i_lock);



	if (!atomic_read(&inode->i_count))
@@ -432,7 +428,7 @@ writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, 
		/*

		 * It's a data-integrity sync.  We must wait.

		 */

		inode_wait_for_writeback(inode, wb);

		inode_wait_for_writeback(inode);

	}



	BUG_ON(inode->i_state & I_SYNC);
@@ -440,7 +436,6 @@ writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, 
	/* Set I_SYNC, reset I_DIRTY_PAGES */

	inode->i_state |= I_SYNC;

	spin_unlock(&inode->i_lock);

	spin_unlock(&wb->list_lock);



	ret = do_writepages(mapping, wbc);
@@ -587,6 +582,8 @@ static long writeback_sb_inodes(struct super_block *sb, 
			trace_writeback_sb_inodes_requeue(inode);

			continue;

		}

		spin_unlock(&wb->list_lock);



		__iget(inode);

		write_chunk = writeback_chunk_size(wb->bdi, work);

		wbc.nr_to_write = write_chunk;
@@ -803,8 +800,10 @@ static long wb_writeback(struct bdi_writeback *wb, 
			trace_writeback_wait(wb->bdi, work);

			inode = wb_inode(wb->b_more_io.prev);

			spin_lock(&inode->i_lock);

			inode_wait_for_writeback(inode, wb);

			spin_unlock(&wb->list_lock);

			inode_wait_for_writeback(inode);

			spin_unlock(&inode->i_lock);

			spin_lock(&wb->list_lock);

		}

	}

	spin_unlock(&wb->list_lock);
@@ -1350,7 +1349,6 @@ int write_inode_now(struct inode *inode, int sync) 
		wbc.nr_to_write = 0;



	might_sleep();

	spin_lock(&wb->list_lock);

	spin_lock(&inode->i_lock);

	ret = writeback_single_inode(inode, wb, &wbc);

	spin_unlock(&inode->i_lock);
@@ -1375,7 +1373,6 @@ int sync_inode(struct inode *inode, struct writeback_control *wbc) 
	struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;

	int ret;



	spin_lock(&wb->list_lock);

	spin_lock(&inode->i_lock);

	ret = writeback_single_inode(inode, wb, wbc);

	spin_unlock(&inode->i_lock);