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>

3 files changed, 16 insertions, 4 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;
 }
 
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 7e70506297bc..d53af8f15236 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -687,7 +687,7 @@ static int fuse_readpage(struct file *file, struct page *page)
                 SetPageUptodate(page);
         }
 
-        fuse_invalidate_attr(inode); /* atime changed */
+        fuse_invalidate_atime(inode);
  out:
         unlock_page(page);
         return err;
@@ -716,7 +716,7 @@ static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
                         fuse_read_update_size(inode, pos,
                                               req->misc.read.attr_ver);
                 }
-                fuse_invalidate_attr(inode); /* atime changed */
+                fuse_invalidate_atime(inode);
         }
 
         for (i = 0; i < req->num_pages; i++) {
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 7d2730912667..dc44b9e3a0c9 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -788,6 +788,8 @@ void fuse_invalidate_attr(struct inode *inode);
 
 void fuse_invalidate_entry_cache(struct dentry *entry);
 
+void fuse_invalidate_atime(struct inode *inode);
+
 /**
  * Acquire reference to fuse_conn
  */