f2fs: support plain user/group quota

This patch adds to support plain user/group quota.

Change Note by Jaegeuk Kim.

- Use f2fs page cache for quota files in order to consider garbage collection.
  so, quota files are not tolerable for sudden power-cuts, so user needs to do
  quotacheck.

- setattr() calls dquot_transfer which will transfer inode->i_blocks.
  We can't reclaim that during f2fs_evict_inode(). So, we need to count
  node blocks as well in order to match i_blocks with dquot's space.

  Note that, Chao wrote a patch to count inode->i_blocks without inode block.
  (f2fs: don't count inode block in in-memory inode.i_blocks)

- in f2fs_remount, we need to make RW in prior to dquot_resume.

- handle fault_injection case during f2fs_quota_off_umount

- TODO: Project quota

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

 Conflicts:
	fs/f2fs/namei.c
	fs/f2fs/super.c

1 files changed, 4 insertions, 5 deletions

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index c1c139b73..1f6fb95fb 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1050,10 +1050,9 @@ struct page *new_node_page(struct dnode_of_data *dn,
 	if (!page)
 		return ERR_PTR(-ENOMEM);
 
-	if (unlikely(!inc_valid_node_count(sbi, dn->inode, !ofs))) {
-		err = -ENOSPC;
+	if (unlikely((err = inc_valid_node_count(sbi, dn->inode, !ofs))))
 		goto fail;
-	}
+
 #ifdef CONFIG_F2FS_CHECK_FS
 	get_node_info(sbi, dn->nid, &new_ni);
 	f2fs_bug_on(sbi, new_ni.blk_addr != NULL_ADDR);
@@ -2230,7 +2229,7 @@ recover_xnid:
 	/* 2: update xattr nid in inode */
 	remove_free_nid(sbi, new_xnid);
 	f2fs_i_xnid_write(inode, new_xnid);
-	if (unlikely(!inc_valid_node_count(sbi, inode, false)))
+	if (unlikely(inc_valid_node_count(sbi, inode, false)))
 		f2fs_bug_on(sbi, 1);
 	update_inode_page(inode);
 
@@ -2288,7 +2287,7 @@ retry:
 	new_ni = old_ni;
 	new_ni.ino = ino;
 
-	if (unlikely(!inc_valid_node_count(sbi, NULL, true)))
+	if (unlikely(inc_valid_node_count(sbi, NULL, true)))
 		WARN_ON(1);
 	set_node_addr(sbi, &new_ni, NEW_ADDR, false);
 	inc_valid_inode_count(sbi);