2015-10-02 14:58:02

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH] NFS: Fix up page writeback accounting

Currently, we are crediting all the calls to nfs_writepages_callback()
(i.e. the nfs_writepages() callback) to nfs_writepage(). Aside from
being inconsistent with the behaviour of the equivalent readpage/readpages
accounting, this also means that we cannot distinguish between bulk writes
and single page writebacks (which confuses the 'nfsiostat -p' tool).

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/write.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 72624dc4a623..cfa47761a8ce 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -569,19 +569,17 @@ static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
if (!nfs_pageio_add_request(pgio, req)) {
nfs_redirty_request(req);
ret = pgio->pg_error;
- }
+ } else
+ nfs_add_stats(page_file_mapping(page)->host,
+ NFSIOS_WRITEPAGES, 1);
out:
return ret;
}

static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
{
- struct inode *inode = page_file_mapping(page)->host;
int ret;

- nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
- nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
-
nfs_pageio_cond_complete(pgio, page_file_index(page));
ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE);
if (ret == -EAGAIN) {
@@ -597,9 +595,11 @@ static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, st
static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
{
struct nfs_pageio_descriptor pgio;
+ struct inode *inode = page_file_mapping(page)->host;
int err;

- nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc),
+ nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
+ nfs_pageio_init_write(&pgio, inode, wb_priority(wbc),
false, &nfs_async_write_completion_ops);
err = nfs_do_writepage(page, wbc, &pgio);
nfs_pageio_complete(&pgio);
--
2.4.3