quota: check quota reservation on remove_dquot_ref

Reserved space must being claimed before remove_dquot_ref() for a
given inode. Filesystem is responsible for performing force blocks
allocation in case of dealloc in ->quota_off. Let's add sanity check
for that case. Do it similar to add_dquot_ref().

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 12 insertions, 1 deletions

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 12c233da1b6b..a5974c49a78b 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -986,6 +986,7 @@ static void remove_dquot_ref(struct super_block *sb, int type,
                 struct list_head *tofree_head)
 {
         struct inode *inode;
+        int reserved = 0;
 
         spin_lock(&inode_lock);
         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
@@ -995,10 +996,20 @@ static void remove_dquot_ref(struct super_block *sb, int type,
                  *  only quota pointers and these have separate locking
                  *  (dqptr_sem).
                  */
-                if (!IS_NOQUOTA(inode))
+                if (!IS_NOQUOTA(inode)) {
+                        if (unlikely(inode_get_rsv_space(inode) > 0))
+                                reserved = 1;
                         remove_inode_dquot_ref(inode, type, tofree_head);
+                }
         }
         spin_unlock(&inode_lock);
+#ifdef CONFIG_QUOTA_DEBUG
+        if (reserved) {
+                printk(KERN_WARNING "VFS (%s): Writes happened after quota"
+                        " was disabled thus quota information is probably "
+                        "inconsistent. Please run quotacheck(8).\n", sb->s_id);
+        }
+#endif
 }
 
 /* Gather all references from inodes and drop them */