Merge branch 'for-4.2/writeback' of git://git.kernel.dk/linux-block

Pull cgroup writeback support from Jens Axboe:
 "This is the big pull request for adding cgroup writeback support.

  This code has been in development for a long time, and it has been
  simmering in for-next for a good chunk of this cycle too.  This is one
  of those problems that has been talked about for at least half a
  decade, finally there's a solution and code to go with it.

  Also see last weeks writeup on LWN:

        http://lwn.net/Articles/648292/"

* 'for-4.2/writeback' of git://git.kernel.dk/linux-block: (85 commits)
  writeback, blkio: add documentation for cgroup writeback support
  vfs, writeback: replace FS_CGROUP_WRITEBACK with SB_I_CGROUPWB
  writeback: do foreign inode detection iff cgroup writeback is enabled
  v9fs: fix error handling in v9fs_session_init()
  bdi: fix wrong error return value in cgwb_create()
  buffer: remove unusued 'ret' variable
  writeback: disassociate inodes from dying bdi_writebacks
  writeback: implement foreign cgroup inode bdi_writeback switching
  writeback: add lockdep annotation to inode_to_wb()
  writeback: use unlocked_inode_to_wb transaction in inode_congested()
  writeback: implement unlocked_inode_to_wb transaction and use it for stat updates
  writeback: implement [locked_]inode_to_wb_and_lock_list()
  writeback: implement foreign cgroup inode detection
  writeback: make writeback_control track the inode being written back
  writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb()
  mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use
  writeback: implement memcg writeback domain based throttling
  writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes
  writeback: implement memcg wb_domain
  writeback: update wb_over_bg_thresh() to use wb_domain aware operations
  ...

2 files changed, 24 insertions, 34 deletions

diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index 620d93489539..8aa56bb6e861 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -320,31 +320,21 @@ fail_option_alloc:
 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 		  const char *dev_name, char *data)
 {
-	int retval = -EINVAL;
 	struct p9_fid *fid;
-	int rc;
+	int rc = -ENOMEM;
 
 	v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
 	if (!v9ses->uname)
-		return ERR_PTR(-ENOMEM);
+		goto err_names;
 
 	v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
-	if (!v9ses->aname) {
-		kfree(v9ses->uname);
-		return ERR_PTR(-ENOMEM);
-	}
+	if (!v9ses->aname)
+		goto err_names;
 	init_rwsem(&v9ses->rename_sem);
 
 	rc = bdi_setup_and_register(&v9ses->bdi, "9p");
-	if (rc) {
-		kfree(v9ses->aname);
-		kfree(v9ses->uname);
-		return ERR_PTR(rc);
-	}
-
-	spin_lock(&v9fs_sessionlist_lock);
-	list_add(&v9ses->slist, &v9fs_sessionlist);
-	spin_unlock(&v9fs_sessionlist_lock);
+	if (rc)
+		goto err_names;
 
 	v9ses->uid = INVALID_UID;
 	v9ses->dfltuid = V9FS_DEFUID;
@@ -352,10 +342,9 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 
 	v9ses->clnt = p9_client_create(dev_name, data);
 	if (IS_ERR(v9ses->clnt)) {
-		retval = PTR_ERR(v9ses->clnt);
-		v9ses->clnt = NULL;
+		rc = PTR_ERR(v9ses->clnt);
 		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
-		goto error;
+		goto err_bdi;
 	}
 
 	v9ses->flags = V9FS_ACCESS_USER;
@@ -368,10 +357,8 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 	}
 
 	rc = v9fs_parse_options(v9ses, data);
-	if (rc < 0) {
-		retval = rc;
-		goto error;
-	}
+	if (rc < 0)
+		goto err_clnt;
 
 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 
@@ -405,10 +392,9 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
 							v9ses->aname);
 	if (IS_ERR(fid)) {
-		retval = PTR_ERR(fid);
-		fid = NULL;
+		rc = PTR_ERR(fid);
 		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
-		goto error;
+		goto err_clnt;
 	}
 
 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
@@ -420,12 +406,20 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 	/* register the session for caching */
 	v9fs_cache_session_get_cookie(v9ses);
 #endif
+	spin_lock(&v9fs_sessionlist_lock);
+	list_add(&v9ses->slist, &v9fs_sessionlist);
+	spin_unlock(&v9fs_sessionlist_lock);
 
 	return fid;
 
-error:
+err_clnt:
+	p9_client_destroy(v9ses->clnt);
+err_bdi:
 	bdi_destroy(&v9ses->bdi);
-	return ERR_PTR(retval);
+err_names:
+	kfree(v9ses->uname);
+	kfree(v9ses->aname);
+	return ERR_PTR(rc);
 }
 
 /**
diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index e99a338a4638..bf495cedec26 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -130,11 +130,7 @@ static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 	fid = v9fs_session_init(v9ses, dev_name, data);
 	if (IS_ERR(fid)) {
 		retval = PTR_ERR(fid);
-		/*
-		 * we need to call session_close to tear down some
-		 * of the data structure setup by session_init
-		 */
-		goto close_session;
+		goto free_session;
 	}
 
 	sb = sget(fs_type, NULL, v9fs_set_super, flags, v9ses);
@@ -195,8 +191,8 @@ static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 
 clunk_fid:
 	p9_client_clunk(fid);
-close_session:
 	v9fs_session_close(v9ses);
+free_session:
 	kfree(v9ses);
 	return ERR_PTR(retval);