quota: Add callbacks for allocating and destroying dquot structures

Some filesystems would like to keep private information together with each
dquot. Add callbacks alloc_dquot and destroy_dquot allowing filesystem to
allocate larger dquots from their private slab in a similar fashion we
currently allocate inodes.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

diff --git a/fs/dquot.c b/fs/dquot.c
index c237ccc..1b5fc4b 100644 (file)
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -415,6 +415,16 @@ out_dqlock:
        return ret;
 }
 
+static void dquot_destroy(struct dquot *dquot)
+{
+       kmem_cache_free(dquot_cachep, dquot);
+}
+
+static inline void do_destroy_dquot(struct dquot *dquot)
+{
+       dquot->dq_sb->dq_op->destroy_dquot(dquot);
+}
+
 /* Invalidate all dquots on the list. Note that this function is called after
  * quota is disabled and pointers from inodes removed so there cannot be new
  * quota users. There can still be some users of quotas due to inodes being
@@ -463,7 +473,7 @@ restart:
                remove_dquot_hash(dquot);
                remove_free_dquot(dquot);
                remove_inuse(dquot);
-               kmem_cache_free(dquot_cachep, dquot);
+               do_destroy_dquot(dquot);
        }
        spin_unlock(&dq_list_lock);
 }
@@ -527,7 +537,7 @@ static void prune_dqcache(int count)
                remove_dquot_hash(dquot);
                remove_free_dquot(dquot);
                remove_inuse(dquot);
-               kmem_cache_free(dquot_cachep, dquot);
+               do_destroy_dquot(dquot);
                count--;
                head = free_dquots.prev;
        }
@@ -625,11 +635,16 @@ we_slept:
        spin_unlock(&dq_list_lock);
 }
 
+static struct dquot *dquot_alloc(struct super_block *sb, int type)
+{
+       return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
+}
+
 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
 {
        struct dquot *dquot;
 
-       dquot = kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
+       dquot = sb->dq_op->alloc_dquot(sb, type);
        if(!dquot)
                return NODQUOT;
 
@@ -682,7 +697,7 @@ we_slept:
                dqstats.lookups++;
                spin_unlock(&dq_list_lock);
                if (empty)
-                       kmem_cache_free(dquot_cachep, empty);
+                       do_destroy_dquot(empty);
        }
        /* Wait for dq_lock - after this we know that either dquot_release() is already
         * finished or it will be canceled due to dq_count > 1 test */
@@ -1533,7 +1548,9 @@ struct dquot_operations dquot_operations = {
        .acquire_dquot  = dquot_acquire,
        .release_dquot  = dquot_release,
        .mark_dirty     = dquot_mark_dquot_dirty,
-       .write_info     = dquot_commit_info
+       .write_info     = dquot_commit_info,
+       .alloc_dquot    = dquot_alloc,
+       .destroy_dquot  = dquot_destroy,
 };
 
 static inline void set_enable_flags(struct quota_info *dqopt, int type)

diff --git a/include/linux/quota.h b/include/linux/quota.h
index 40401b5..3ce708c 100644 (file)
--- a/include/linux/quota.h
+++ b/include/linux/quota.h
@@ -292,6 +292,8 @@ struct dquot_operations {
        int (*free_inode) (const struct inode *, unsigned long);
        int (*transfer) (struct inode *, struct iattr *);
        int (*write_dquot) (struct dquot *);            /* Ordinary dquot write */
+       struct dquot *(*alloc_dquot)(struct super_block *, int);        /* Allocate memory for new dquot */
+       void (*destroy_dquot)(struct dquot *);          /* Free memory for dquot */
        int (*acquire_dquot) (struct dquot *);          /* Quota is going to be created on disk */
        int (*release_dquot) (struct dquot *);          /* Quota is going to be deleted from disk */
        int (*mark_dirty) (struct dquot *);             /* Dquot is marked dirty */