[PATCH 3.16 280/305] fuse: cleanup fuse_file refcounting

[Ben Hutchings]

3.16.63-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Miklos Szeredi <mszer...@redhat.com>

commit 267d84449f52349ee252db684ed95ede18e51744 upstream.

struct fuse_file is stored in file->private_data.  Make this always be a
counting reference for consistency.

This also allows fuse_sync_release() to call fuse_file_put() instead of
partially duplicating its functionality.

Signed-off-by: Miklos Szeredi <mszer...@redhat.com>
[bwh: Backported to 3.16: force and background flags are bitfields]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
 fs/fuse/dir.c    |  2 +-
 fs/fuse/file.c   | 18 +++++++++---------
 fs/fuse/fuse_i.h |  1 -
 3 files changed, 10 insertions(+), 11 deletions(-)

--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -488,7 +488,7 @@ static int fuse_create_open(struct inode
        if (err) {
                fuse_sync_release(ff, flags);
        } else {
-               file->private_data = fuse_file_get(ff);
+               file->private_data = ff;
                fuse_finish_open(inode, file);
        }
        return err;
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -66,7 +66,7 @@ struct fuse_file *fuse_file_alloc(struct
        }
 
        INIT_LIST_HEAD(&ff->write_entry);
-       atomic_set(&ff->count, 0);
+       atomic_set(&ff->count, 1);
        RB_CLEAR_NODE(&ff->polled_node);
        init_waitqueue_head(&ff->poll_wait);
 
@@ -83,7 +83,7 @@ void fuse_file_free(struct fuse_file *ff
        kfree(ff);
 }
 
-struct fuse_file *fuse_file_get(struct fuse_file *ff)
+static struct fuse_file *fuse_file_get(struct fuse_file *ff)
 {
        atomic_inc(&ff->count);
        return ff;
@@ -183,7 +183,7 @@ int fuse_do_open(struct fuse_conn *fc, u
                ff->open_flags &= ~FOPEN_DIRECT_IO;
 
        ff->nodeid = nodeid;
-       file->private_data = fuse_file_get(ff);
+       file->private_data = ff;
 
        return 0;
 }
@@ -335,13 +335,13 @@ static int fuse_release(struct inode *in
 
 void fuse_sync_release(struct fuse_file *ff, int flags)
 {
-       WARN_ON(atomic_read(&ff->count) > 1);
+       WARN_ON(atomic_read(&ff->count) != 1);
        fuse_prepare_release(ff, flags, FUSE_RELEASE);
-       ff->reserved_req->force = 1;
-       ff->reserved_req->background = 0;
-       fuse_request_send(ff->fc, ff->reserved_req);
-       fuse_put_request(ff->fc, ff->reserved_req);
-       kfree(ff);
+       /*
+        * iput(NULL) is a no-op and since the refcount is 1 and everything's
+        * synchronous, we are fine with not doing igrab() here"
+        */
+       fuse_file_put(ff, true);
 }
 EXPORT_SYMBOL_GPL(fuse_sync_release);
 
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -663,7 +663,6 @@ void fuse_read_fill(struct fuse_req *req
 int fuse_open_common(struct inode *inode, struct file *file, bool isdir);
 
 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc);
-struct fuse_file *fuse_file_get(struct fuse_file *ff);
 void fuse_file_free(struct fuse_file *ff);
 void fuse_finish_open(struct inode *inode, struct file *file);