linux-kernel - [PATCH 07/10] nfs: honor AT_STATX_DONT

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Date:   Wed, 20 Sep 2017 10:40:02 +0200
From:   Miklos Szeredi <mszeredi@...hat.com>
To:     linux-fsdevel@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, Al Viro <viro@...iv.linux.org.uk>,
        David Howells <dhowells@...hat.com>,
        Trond Myklebust <trond.myklebust@...marydata.com>,
        Anna Schumaker <anna.schumaker@...app.com>
Subject: [PATCH 07/10] nfs: honor AT_STATX_DONT_SYNC

The description of this flag says "Don't sync attributes with the server".
In other words: always use the attributes cached in the kernel and don't
send network or local messages to refresh the attributes.

Signed-off-by: Miklos Szeredi <mszeredi@...hat.com>
Cc: Trond Myklebust <trond.myklebust@...marydata.com>
Cc: Anna Schumaker <anna.schumaker@...app.com>
---
 fs/nfs/inode.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 134d9f560240..487e99ba7d33 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -739,6 +739,10 @@ int nfs_getattr(const struct path *path, struct kstat *stat,
 	int err = 0;
 
 	trace_nfs_getattr_enter(inode);
+
+	if (query_flags & AT_STATX_DONT_SYNC)
+		goto out;
+
 	/* Flush out writes to the server in order to update c/mtime.  */
 	if (S_ISREG(inode->i_mode)) {
 		err = filemap_write_and_wait(inode->i_mapping);
@@ -769,13 +773,13 @@ int nfs_getattr(const struct path *path, struct kstat *stat,
 		err = __nfs_revalidate_inode(server, inode);
 	} else
 		nfs_readdirplus_parent_cache_hit(path->dentry);
+out:
 	if (!err) {
 		generic_fillattr(inode, stat);
 		stat->ino = nfs_compat_user_ino64(NFS_FILEID(inode));
 		if (S_ISDIR(inode->i_mode))
 			stat->blksize = NFS_SERVER(inode)->dtsize;
 	}
-out:
 	trace_nfs_getattr_exit(inode, err);
 	return err;
 }
-- 
2.5.5