[PATCH 09/18] writeback: elevate queue_io() into wb_writeback()

Wu Fengguang
2011-05-24T05:26:35Z

[-- Attachment #1: move-queue_io.patch --]
[-- Type: text/plain, Size: 3402 bytes --]

Code refactor for more logical code layout.
No behavior change.

- remove the mis-named __writeback_inodes_sb()

- wb_writeback()/writeback_inodes_wb() will decide when to queue_io()
before calling __writeback_inodes_wb()

Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
fs/fs-writeback.c | 29 ++++++++++++-----------------
1 file changed, 12 insertions(+), 17 deletions(-)

--- linux-next.orig/fs/fs-writeback.c 2011-05-24 11:17:20.000000000 +0800
+++ linux-next/fs/fs-writeback.c 2011-05-24 11:17:21.000000000 +0800
@@ -580,17 +580,13 @@ static int writeback_sb_inodes(struct su
return 1;
}

-void writeback_inodes_wb(struct bdi_writeback *wb,
- struct writeback_control *wbc)
+static void __writeback_inodes_wb(struct bdi_writeback *wb,
+ struct writeback_control *wbc)
{
int ret = 0;

if (!wbc->wb_start)
wbc->wb_start = jiffies; /* livelock avoidance */
- spin_lock(&wb->list_lock);
-
- if (list_empty(&wb->b_io))
- queue_io(wb, wbc->older_than_this);

while (!list_empty(&wb->b_io)) {
struct inode *inode = wb_inode(wb->b_io.prev);
@@ -606,19 +602,16 @@ void writeback_inodes_wb(struct bdi_writ
if (ret)
break;
}
- spin_unlock(&wb->list_lock);
/* Leave any unwritten inodes on b_io */
}

-static void __writeback_inodes_sb(struct super_block *sb,
- struct bdi_writeback *wb, struct writeback_control *wbc)
+void writeback_inodes_wb(struct bdi_writeback *wb,
+ struct writeback_control *wbc)
{
- WARN_ON(!rwsem_is_locked(&sb->s_umount));
-
spin_lock(&wb->list_lock);
if (list_empty(&wb->b_io))
queue_io(wb, wbc->older_than_this);
- writeback_sb_inodes(sb, wb, wbc, true);
+ __writeback_inodes_wb(wb, wbc);
spin_unlock(&wb->list_lock);
}

@@ -685,7 +678,7 @@ static long wb_writeback(struct bdi_writ
* The intended call sequence for WB_SYNC_ALL writeback is:
*
* wb_writeback()
- * __writeback_inodes_sb() <== called only once
+ * writeback_sb_inodes() <== called only once
* write_cache_pages() <== called once for each inode
* (quickly) tag currently dirty pages
* (maybe slowly) sync all tagged pages
@@ -694,6 +687,7 @@ static long wb_writeback(struct bdi_writ
write_chunk = LONG_MAX;

wbc.wb_start = jiffies; /* livelock avoidance */
+ spin_lock(&wb->list_lock);
for (;;) {
/*
* Stop writeback when nr_pages has been consumed
@@ -731,10 +725,12 @@ static long wb_writeback(struct bdi_writ

retry:
trace_wbc_writeback_start(&wbc, wb->bdi);
+ if (list_empty(&wb->b_io))
+ queue_io(wb, wbc.older_than_this);
if (work->sb)
- __writeback_inodes_sb(work->sb, wb, &wbc);
+ writeback_sb_inodes(work->sb, wb, &wbc, true);
else
- writeback_inodes_wb(wb, &wbc);
+ __writeback_inodes_wb(wb, &wbc);
trace_wbc_writeback_written(&wbc, wb->bdi);

work->nr_pages -= write_chunk - wbc.nr_to_write;
@@ -775,7 +771,6 @@ retry:
* become available for writeback. Otherwise
* we'll just busyloop.
*/
- spin_lock(&wb->list_lock);
if (!list_empty(&wb->b_more_io)) {
inode = wb_inode(wb->b_more_io.prev);
trace_wbc_writeback_wait(&wbc, wb->bdi);
@@ -783,8 +778,8 @@ retry:
inode_wait_for_writeback(inode, wb);
spin_unlock(&inode->i_lock);
}
- spin_unlock(&wb->list_lock);
}
+ spin_unlock(&wb->list_lock);

return wrote;
}