mm: write_cache_pages integrity fix

[safe/jmp/linux-2.6] / fs / dquot.c

diff --git a/fs/dquot.c b/fs/dquot.c
index ae8fd9e..61bfff6 100644 (file)
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -413,10 +413,11 @@ out_dqlock:
        return ret;
 }
 
-static void dquot_destroy(struct dquot *dquot)
+void dquot_destroy(struct dquot *dquot)
 {
        kmem_cache_free(dquot_cachep, dquot);
 }
+EXPORT_SYMBOL(dquot_destroy);
 
 static inline void do_destroy_dquot(struct dquot *dquot)
 {
@@ -476,6 +477,41 @@ restart:
        spin_unlock(&dq_list_lock);
 }
 
+/* Call callback for every active dquot on given filesystem */
+int dquot_scan_active(struct super_block *sb,
+                     int (*fn)(struct dquot *dquot, unsigned long priv),
+                     unsigned long priv)
+{
+       struct dquot *dquot, *old_dquot = NULL;
+       int ret = 0;
+
+       mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
+       spin_lock(&dq_list_lock);
+       list_for_each_entry(dquot, &inuse_list, dq_inuse) {
+               if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
+                       continue;
+               if (dquot->dq_sb != sb)
+                       continue;
+               /* Now we have active dquot so we can just increase use count */
+               atomic_inc(&dquot->dq_count);
+               dqstats.lookups++;
+               spin_unlock(&dq_list_lock);
+               dqput(old_dquot);
+               old_dquot = dquot;
+               ret = fn(dquot, priv);
+               if (ret < 0)
+                       goto out;
+               spin_lock(&dq_list_lock);
+               /* We are safe to continue now because our dquot could not
+                * be moved out of the inuse list while we hold the reference */
+       }
+       spin_unlock(&dq_list_lock);
+out:
+       dqput(old_dquot);
+       mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
+       return ret;
+}
+
 int vfs_quota_sync(struct super_block *sb, int type)
 {
        struct list_head *dirty;
@@ -633,10 +669,11 @@ we_slept:
        spin_unlock(&dq_list_lock);
 }
 
-static struct dquot *dquot_alloc(struct super_block *sb, int type)
+struct dquot *dquot_alloc(struct super_block *sb, int type)
 {
        return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
 }
+EXPORT_SYMBOL(dquot_alloc);
 
 static struct dquot *get_empty_dquot(struct super_block *sb, int type)
 {
@@ -2318,6 +2355,7 @@ EXPORT_SYMBOL(vfs_quota_on_path);
 EXPORT_SYMBOL(vfs_quota_on_mount);
 EXPORT_SYMBOL(vfs_quota_disable);
 EXPORT_SYMBOL(vfs_quota_off);
+EXPORT_SYMBOL(dquot_scan_active);
 EXPORT_SYMBOL(vfs_quota_sync);
 EXPORT_SYMBOL(vfs_get_dqinfo);
 EXPORT_SYMBOL(vfs_set_dqinfo);