LU-8801 quota: fix ldiskfs accounting iterator

[fs/lustre-release.git] / lustre / quota / lproc_quota.c

diff --git a/lustre/quota/lproc_quota.c b/lustre/quota/lproc_quota.c
index 8c8ad65..1f2584f 100644 (file)
--- a/lustre/quota/lproc_quota.c
+++ b/lustre/quota/lproc_quota.c
@@ -41,8 +41,11 @@
  * It is passed to seq_start/stop/next/show which can thus use the same lu_env
  * to be used with the iterator API */
 struct lquota_procfs {
-       struct dt_object        *lqp_obj;
-       struct lu_env            lqp_env;
+       struct dt_object *lqp_obj;
+       struct lu_env lqp_env;
+       struct dt_it *lqp_it;
+       __u64 lqp_cookie;
+       __u64 lqp_first_cookie;
 };
 
 /* global shared environment */
@@ -58,27 +61,20 @@ static void *lprocfs_quota_seq_start(struct seq_file *p, loff_t *pos)
 
        if (offset == 0)
                return SEQ_START_TOKEN;
-       offset--;
 
        if (lqp->lqp_obj == NULL)
                /* accounting not enabled. */
                return NULL;
 
-       /* initialize iterator */
-       iops = &lqp->lqp_obj->do_index_ops->dio_it;
-       it = iops->init(&lqp->lqp_env, lqp->lqp_obj, 0);
-       if (IS_ERR(it)) {
-               CERROR("%s: failed to initialize iterator: rc = %ld\n",
-                      lqp->lqp_obj->do_lu.lo_dev->ld_obd->obd_name,
-                      PTR_ERR(it));
+       if (lqp->lqp_it == NULL) /* reach the end */
                return NULL;
-       }
 
-       /* move on to the first valid record */
-       rc = iops->load(&lqp->lqp_env, it, 0);
-       if (rc < 0) { /* Error */
-               goto not_found;
-       } else if (rc == 0) {
+       offset--;
+       /* move on to the the last processed entry */
+       iops = &lqp->lqp_obj->do_index_ops->dio_it;
+       it = lqp->lqp_it;
+       rc = iops->load(&lqp->lqp_env, it, lqp->lqp_cookie);
+       if (rc == 0 && offset == 0) {
                /*
                 * Iterator didn't find record with exactly the key requested.
                 *
@@ -92,17 +88,25 @@ static void *lprocfs_quota_seq_start(struct seq_file *p, loff_t *pos)
                rc = iops->next(&lqp->lqp_env, it);
                if (rc != 0)
                        goto not_found;
+               lqp->lqp_cookie = iops->store(&lqp->lqp_env, it);
+       } else if (rc <= 0) {
+               goto not_found;
        }
-       while (offset--) {
-               rc = iops->next(&lqp->lqp_env, it);
-               if (rc != 0) /* Error or reach the end */
-                       goto not_found;
-       }
+
+       /* The id entry could be deleted while iteration, and above ->load()
+        * operation will reset cursor to the first cookie (ldiskfs), we
+        * need to break in such situation. */
+       if (offset == 0)
+               lqp->lqp_first_cookie = lqp->lqp_cookie;
+       else if (lqp->lqp_cookie == lqp->lqp_first_cookie)
+               goto not_found;
+
        return it;
 
 not_found:
        iops->put(&lqp->lqp_env, it);
        iops->fini(&lqp->lqp_env, it);
+       lqp->lqp_it = NULL;
        return NULL;
 }
 
@@ -120,7 +124,6 @@ static void lprocfs_quota_seq_stop(struct seq_file *p, void *v)
        /* if something wrong happened during ->seq_show, we need to release
         * the iterator here */
        iops->put(&lqp->lqp_env, it);
-       iops->fini(&lqp->lqp_env, it);
 }
 
 static void *lprocfs_quota_seq_next(struct seq_file *p, void *v, loff_t *pos)
@@ -139,12 +142,17 @@ static void *lprocfs_quota_seq_next(struct seq_file *p, void *v, loff_t *pos)
        if (v == SEQ_START_TOKEN)
                return lprocfs_quota_seq_start(p, pos);
 
+       if (lqp->lqp_it == NULL) /* reach the end */
+               return NULL;
+
        iops = &lqp->lqp_obj->do_index_ops->dio_it;
        it = (struct dt_it *)v;
 
        rc = iops->next(&lqp->lqp_env, it);
-       if (rc == 0)
+       if (rc == 0) {
+               lqp->lqp_cookie = iops->store(&lqp->lqp_env, it);
                return it;
+       }
 
        if (rc < 0)
                CERROR("%s: seq_next failed: rc = %d\n",
@@ -153,6 +161,7 @@ static void *lprocfs_quota_seq_next(struct seq_file *p, void *v, loff_t *pos)
        /* Reach the end or error */
        iops->put(&lqp->lqp_env, it);
        iops->fini(&lqp->lqp_env, it);
+       lqp->lqp_it = NULL;
        return NULL;
 }
 
@@ -254,6 +263,8 @@ static int lprocfs_quota_seq_open(struct inode *inode, struct file *file)
        struct seq_file         *seq;
        int                      rc;
        struct lquota_procfs    *lqp;
+       const struct dt_it_ops  *iops;
+       struct dt_it *it;
 
        /* Allocate quota procfs data. This structure will be passed to
         * seq_start/stop/next/show via seq->private */
@@ -285,6 +296,20 @@ static int lprocfs_quota_seq_open(struct inode *inode, struct file *file)
        if (rc)
                goto out_env;
 
+       /* initialize iterator */
+       iops = &lqp->lqp_obj->do_index_ops->dio_it;
+       it = iops->init(&lqp->lqp_env, lqp->lqp_obj, 0);
+       if (IS_ERR(it)) {
+               rc = PTR_ERR(it);
+               CERROR("%s: failed to initialize iterator: rc = %ld\n",
+                      lqp->lqp_obj->do_lu.lo_dev->ld_obd->obd_name,
+                      PTR_ERR(it));
+               seq_release(inode, file);
+               goto out_env;
+       }
+       lqp->lqp_it = it;
+       lqp->lqp_cookie = 0;
+
        seq = file->private_data;
        seq->private = lqp;
        return 0;
@@ -300,8 +325,12 @@ static int lprocfs_quota_seq_release(struct inode *inode, struct file *file)
 {
        struct seq_file         *seq = file->private_data;
        struct lquota_procfs    *lqp = seq->private;
+       const struct dt_it_ops  *iops;
 
        LASSERT(lqp);
+       iops = &lqp->lqp_obj->do_index_ops->dio_it;
+       if (lqp->lqp_it != NULL)
+               iops->fini(&lqp->lqp_env, lqp->lqp_it);
        lu_env_fini(&lqp->lqp_env);
        OBD_FREE_PTR(lqp);