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authorJan Kara <jack@suse.cz>2013-06-28 16:04:02 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-07-28 16:29:40 -0700
commit9fa65e09730a2e63c5b45d008f269b2b271b74bc (patch)
tree547d92c9b2b7b174214e3aea35113610a074d419
parent81a464838675307c9fc7909fc840f248ed2caed5 (diff)
writeback: Fix periodic writeback after fs mount
commit a5faeaf9109578e65e1a32e2a3e76c8b47e7dcb6 upstream. Code in blkdev.c moves a device inode to default_backing_dev_info when the last reference to the device is put and moves the device inode back to its bdi when the first reference is acquired. This includes moving to wb.b_dirty list if the device inode is dirty. The code however doesn't setup timer to wake corresponding flusher thread and while wb.b_dirty list is non-empty __mark_inode_dirty() will not set it up either. Thus periodic writeback is effectively disabled until a sync(2) call which can lead to unexpected data loss in case of crash or power failure. Fix the problem by setting up a timer for periodic writeback in case we add the first dirty inode to wb.b_dirty list in bdev_inode_switch_bdi(). Reported-by: Bert De Jonghe <Bert.DeJonghe@amplidata.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/block_dev.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 2091db8cdd78..85f5c85ec91c 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -58,17 +58,24 @@ static void bdev_inode_switch_bdi(struct inode *inode,
struct backing_dev_info *dst)
{
struct backing_dev_info *old = inode->i_data.backing_dev_info;
+ bool wakeup_bdi = false;
if (unlikely(dst == old)) /* deadlock avoidance */
return;
bdi_lock_two(&old->wb, &dst->wb);
spin_lock(&inode->i_lock);
inode->i_data.backing_dev_info = dst;
- if (inode->i_state & I_DIRTY)
+ if (inode->i_state & I_DIRTY) {
+ if (bdi_cap_writeback_dirty(dst) && !wb_has_dirty_io(&dst->wb))
+ wakeup_bdi = true;
list_move(&inode->i_wb_list, &dst->wb.b_dirty);
+ }
spin_unlock(&inode->i_lock);
spin_unlock(&old->wb.list_lock);
spin_unlock(&dst->wb.list_lock);
+
+ if (wakeup_bdi)
+ bdi_wakeup_thread_delayed(dst);
}
/* Kill _all_ buffers and pagecache , dirty or not.. */