Commit b35250c0 authored by Jan Kara's avatar Jan Kara
Browse files

writeback: Protect inode->i_io_list with inode->i_lock 



Currently, operations on inode->i_io_list are protected by
wb->list_lock. In the following patches we'll need to maintain
consistency between inode->i_state and inode->i_io_list so change the
code so that inode->i_lock protects also all inode's i_io_list handling.

Reviewed-by: default avatarMartijn Coenen <maco@android.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
CC: stable@vger.kernel.org # Prerequisite for "writeback: Avoid skipping inode writeback"
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 5b14671b

fs/fs-writeback.c

+17 −5
Original line number Diff line number Diff line
@@ -144,6 +144,7 @@ static void inode_io_list_del_locked(struct inode *inode, 
				     struct bdi_writeback *wb)

{

	assert_spin_locked(&wb->list_lock);

	assert_spin_locked(&inode->i_lock);



	list_del_init(&inode->i_io_list);

	wb_io_lists_depopulated(wb);
@@ -1122,7 +1123,9 @@ void inode_io_list_del(struct inode *inode) 
	struct bdi_writeback *wb;



	wb = inode_to_wb_and_lock_list(inode);

	spin_lock(&inode->i_lock);

	inode_io_list_del_locked(inode, wb);

	spin_unlock(&inode->i_lock);

	spin_unlock(&wb->list_lock);

}

EXPORT_SYMBOL(inode_io_list_del);
@@ -1172,8 +1175,10 @@ void sb_clear_inode_writeback(struct inode *inode) 
 * the case then the inode must have been redirtied while it was being written

 * out and we don't reset its dirtied_when.

 */

static void redirty_tail(struct inode *inode, struct bdi_writeback *wb)

static void redirty_tail_locked(struct inode *inode, struct bdi_writeback *wb)

{

	assert_spin_locked(&inode->i_lock);



	if (!list_empty(&wb->b_dirty)) {

		struct inode *tail;
@@ -1184,6 +1189,13 @@ static void redirty_tail(struct inode *inode, struct bdi_writeback *wb) 
	inode_io_list_move_locked(inode, wb, &wb->b_dirty);

}



static void redirty_tail(struct inode *inode, struct bdi_writeback *wb)

{

	spin_lock(&inode->i_lock);

	redirty_tail_locked(inode, wb);

	spin_unlock(&inode->i_lock);

}



/*

 * requeue inode for re-scanning after bdi->b_io list is exhausted.

 */
@@ -1394,7 +1406,7 @@ static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, 
		 * writeback is not making progress due to locked

		 * buffers. Skip this inode for now.

		 */

		redirty_tail(inode, wb);

		redirty_tail_locked(inode, wb);

		return;

	}
@@ -1414,7 +1426,7 @@ static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, 
			 * retrying writeback of the dirty page/inode

			 * that cannot be performed immediately.

			 */

			redirty_tail(inode, wb);

			redirty_tail_locked(inode, wb);

		}

	} else if (inode->i_state & I_DIRTY) {

		/*
@@ -1422,7 +1434,7 @@ static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, 
		 * such as delayed allocation during submission or metadata

		 * updates after data IO completion.

		 */

		redirty_tail(inode, wb);

		redirty_tail_locked(inode, wb);

	} else if (inode->i_state & I_DIRTY_TIME) {

		inode->dirtied_when = jiffies;

		inode_io_list_move_locked(inode, wb, &wb->b_dirty_time);
@@ -1669,8 +1681,8 @@ static long writeback_sb_inodes(struct super_block *sb, 
		 */

		spin_lock(&inode->i_lock);

		if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {

			redirty_tail_locked(inode, wb);

			spin_unlock(&inode->i_lock);

			redirty_tail(inode, wb);

			continue;

		}

		if ((inode->i_state & I_SYNC) && wbc.sync_mode != WB_SYNC_ALL) {

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