quota: simplify remove_inode_dquot_ref()

Simplify the remove_inode_dquot_ref() to make it more obvious
that now we keep one reference for each dquot from inodes.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 19 insertions, 32 deletions

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 251771916069..fb2d2e2a89e7 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -733,7 +733,6 @@ static struct shrinker dqcache_shrinker = {
 
 /*
  * Put reference to dquot
- * NOTE: If you change this function please check whether dqput_blocks() works right...
  */
 void dqput(struct dquot *dquot)
 {
@@ -963,46 +962,34 @@ static void add_dquot_ref(struct super_block *sb, int type)
 }
 
 /*
- * Return 0 if dqput() won't block.
- * (note that 1 doesn't necessarily mean blocking)
- */
-static inline int dqput_blocks(struct dquot *dquot)
-{
-        if (atomic_read(&dquot->dq_count) <= 1)
-                return 1;
-        return 0;
-}
-
-/*
  * Remove references to dquots from inode and add dquot to list for freeing
  * if we have the last reference to dquot
  * We can't race with anybody because we hold dqptr_sem for writing...
  */
-static int remove_inode_dquot_ref(struct inode *inode, int type,
-                                  struct list_head *tofree_head)
+static void remove_inode_dquot_ref(struct inode *inode, int type,
+                                   struct list_head *tofree_head)
 {
         struct dquot *dquot = inode->i_dquot[type];
 
         inode->i_dquot[type] = NULL;
-        if (dquot) {
-                if (dqput_blocks(dquot)) {
-#ifdef CONFIG_QUOTA_DEBUG
-                        if (atomic_read(&dquot->dq_count) != 1)
-                                quota_error(inode->i_sb, "Adding dquot with "
-                                            "dq_count %d to dispose list",
-                                            atomic_read(&dquot->dq_count));
-#endif
-                        spin_lock(&dq_list_lock);
-                        /* As dquot must have currently users it can't be on
-                         * the free list... */
-                        list_add(&dquot->dq_free, tofree_head);
-                        spin_unlock(&dq_list_lock);
-                        return 1;
-                }
-                else
-                        dqput(dquot);   /* We have guaranteed we won't block */
+        if (!dquot)
+                return;
+
+        if (list_empty(&dquot->dq_free)) {
+                /*
+                 * The inode still has reference to dquot so it can't be in the
+                 * free list
+                 */
+                spin_lock(&dq_list_lock);
+                list_add(&dquot->dq_free, tofree_head);
+                spin_unlock(&dq_list_lock);
+        } else {
+                /*
+                 * Dquot is already in a list to put so we won't drop the last
+                 * reference here.
+                 */
+                dqput(dquot);
         }
-        return 0;
 }
 
 /*