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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 5d3de00..3b87dc8 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -328,8 +328,7 @@
/*
* 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 @@
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 @@
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 @@
/*
* 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 @@
/* 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 @@
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 @@
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 @@
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 @@
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);