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From:   Dave Wysochanski <dwysocha@redhat.com>
To:     Trond Myklebust <trondmy@hammerspace.com>,
        Anna Schumaker <anna.schumaker@netapp.com>
Cc:     linux-nfs@vger.kernel.org, linux-cachefs@redhat.com
Subject: [RFC PATCH v2 02/14] NFS: In nfs_readpage() only increment NFSIOS_READPAGES when read succeeds
Date:   Wed, 29 Jul 2020 10:12:17 -0400
Message-Id: <1596031949-26793-3-git-send-email-dwysocha@redhat.com>
In-Reply-To: <1596031949-26793-1-git-send-email-dwysocha@redhat.com>
References: <1596031949-26793-1-git-send-email-dwysocha@redhat.com>
Sender: linux-nfs-owner@vger.kernel.org
Precedence: bulk

There is a small inconsistency with nfs_readpage() vs nfs_readpages() with
regards to NFSIOS_READPAGES.  In readpage we unconditionally increment
NFSIOS_READPAGES at the top, which means even if the read fails.  In
readpages, we increment NFSIOS_READPAGES at the bottom based on how
many pages were successfully read.  Change readpage to be consistent with
readpages and so NFSIOS_READPAGES only reflects successful, non-fscache
reads.

Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
---
 fs/nfs/read.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index a05fb3904ddf..1153c4e0a155 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -319,7 +319,6 @@ int nfs_readpage(struct file *filp, struct page *page)
 	dprintk("NFS: nfs_readpage (%p %ld@%lu)\n",
 		page, PAGE_SIZE, page_index(page));
 	nfs_inc_stats(inode, NFSIOS_VFSREADPAGE);
-	nfs_add_stats(inode, NFSIOS_READPAGES, 1);
 
 	/*
 	 * Try to flush any pending writes to the file..
@@ -359,6 +358,7 @@ int nfs_readpage(struct file *filp, struct page *page)
 		if (!PageUptodate(page) && !ret)
 			ret = xchg(&ctx->error, 0);
 	}
+	nfs_add_stats(inode, NFSIOS_READPAGES, 1);
 out:
 	put_nfs_open_context(ctx);
 	return ret;
-- 
1.8.3.1