fuse: don't invalidate attrs when not using atime

Various read operations (e.g. readlink, readdir) invalidate the cached
attrs for atime changes.  This patch adds a new function
'fuse_invalidate_atime', which checks for a read-only super block and
avoids the attr invalidation in that case.

Signed-off-by: Andrew Gallagher <andrewjcg@fb.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

1 files changed, 12 insertions, 2 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index c3eb2c46c8f1..1d1292c581c3 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -112,6 +112,16 @@ void fuse_invalidate_attr(struct inode *inode)
 	get_fuse_inode(inode)->i_time = 0;
 }
 
+/**
+ * Mark the attributes as stale due to an atime change.  Avoid the invalidate if
+ * atime is not used.
+ */
+void fuse_invalidate_atime(struct inode *inode)
+{
+	if (!IS_RDONLY(inode))
+		fuse_invalidate_attr(inode);
+}
+
 /*
  * Just mark the entry as stale, so that a next attempt to look it up
  * will result in a new lookup call to userspace
@@ -1371,7 +1381,7 @@ static int fuse_readdir(struct file *file, struct dir_context *ctx)
 	}
 
 	__free_page(page);
-	fuse_invalidate_attr(inode); /* atime changed */
+	fuse_invalidate_atime(inode);
 	return err;
 }
 
@@ -1404,7 +1414,7 @@ static char *read_link(struct dentry *dentry)
 		link[req->out.args[0].size] = '\0';
  out:
 	fuse_put_request(fc, req);
-	fuse_invalidate_attr(inode); /* atime changed */
+	fuse_invalidate_atime(inode);
 	return link;
 }