0001-Btrfs-fix-missing-qgroup-reservation-before-fallocat.patch

From 0f21b61e25f30543703185ca7c3a63fe73aa86e1 Mon Sep 17 00:00:00 2001
From: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Date: Wed, 20 Mar 2013 14:52:18 +0800
Subject: [PATCH] Btrfs: fix missing qgroup reservation before fallocating

From: Wang Shilong <wangsl-fnst@cn.fujitsu.com>

Steps to reproduce:
	mkfs.btrfs <disk>
	mount <disk> <mnt>
	btrfs quota enable <mnt>
	btrfs sub create <mnt>/subv
	btrfs qgroup limit 10M <mnt>/subv
	fallocate --length 20M <mnt>/subv/data

For the above example, fallocating will return successfully which
is not expected, we try to fix it by doing qgroup reservation before
fallocating.

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
---
 fs/btrfs/file.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index af1d060..bdf5cd7 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2141,6 +2141,7 @@ static long btrfs_fallocate(struct file *file, int mode,
 {
 	struct inode *inode = file_inode(file);
 	struct extent_state *cached_state = NULL;
+	struct btrfs_root *root = BTRFS_I(inode)->root;
 	u64 cur_offset;
 	u64 last_byte;
 	u64 alloc_start;
@@ -2168,6 +2169,11 @@ static long btrfs_fallocate(struct file *file, int mode,
 	ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
 	if (ret)
 		return ret;
+	if (root->fs_info->quota_enabled) {
+		ret = btrfs_qgroup_reserve(root, alloc_end - alloc_start);
+		if (ret)
+			goto out_reserve_fail;
+	}
 
 	/*
 	 * wait for ordered IO before we have any locks.  We'll loop again
@@ -2271,6 +2277,9 @@ static long btrfs_fallocate(struct file *file, int mode,
 			     &cached_state, GFP_NOFS);
 out:
 	mutex_unlock(&inode->i_mutex);
+	if (root->fs_info->quota_enabled)
+		btrfs_qgroup_free(root, alloc_end - alloc_start);
+out_reserve_fail:
 	/* Let go of our reservation. */
 	btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
 	return ret;
-- 
1.7.7.6