f2fs: disable f2fs_check_rb_tree_consistence

If there is millions of discard entries cached in rb tree, each
sanity check of it can cause very long latency as held cmd_lock
blocking other lock grabbers.

In other aspect, we have enabled the check very long time, as
we see, there is no such inconsistent condition caused by bugs.

But still we do not choose to kill it directly, instead, adding
an flag to disable the check now, if there is related code change,
we can reuse it to detect bugs.

Signed-off-by: Yunlei He <heyunlei@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 5e236e26641e469168d81cd1687c0b5e867c1f05..efcb45d0e7d3dbd5aeb5145768a06e97ac2ef14f 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -311,6 +311,7 @@ struct discard_cmd_control {
        atomic_t issing_discard;                /* # of issing discard */
        atomic_t discard_cmd_cnt;               /* # of cached cmd count */
        struct rb_root root;                    /* root of discard rb-tree */
+       bool rbtree_check;                      /* config for consistence check */
 };
 
 /* for the list of fsync inodes, used only during recovery */

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 654091ec9cfe9aec407649fd2c705009a3a5c32c..d63d89287c53e71aa1a97227b33fe09ebc9d9eb4 100644 (file)
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1199,8 +1199,9 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
                mutex_lock(&dcc->cmd_lock);
                if (list_empty(pend_list))
                        goto next;
-               f2fs_bug_on(sbi,
-                       !f2fs_check_rb_tree_consistence(sbi, &dcc->root));
+               if (unlikely(dcc->rbtree_check))
+                       f2fs_bug_on(sbi, !f2fs_check_rb_tree_consistence(sbi,
+                                                               &dcc->root));
                blk_start_plug(&plug);
                list_for_each_entry_safe(dc, tmp, pend_list, list) {
                        f2fs_bug_on(sbi, dc->state != D_PREP);
@@ -1752,6 +1753,7 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
        dcc->max_discards = MAIN_SEGS(sbi) << sbi->log_blocks_per_seg;
        dcc->undiscard_blks = 0;
        dcc->root = RB_ROOT;
+       dcc->rbtree_check = false;
 
        init_waitqueue_head(&dcc->discard_wait_queue);
        SM_I(sbi)->dcc_info = dcc;
@@ -2381,7 +2383,9 @@ next:
        issued = 0;
 
        mutex_lock(&dcc->cmd_lock);
-       f2fs_bug_on(sbi, !f2fs_check_rb_tree_consistence(sbi, &dcc->root));
+       if (unlikely(dcc->rbtree_check))
+               f2fs_bug_on(sbi, !f2fs_check_rb_tree_consistence(sbi,
+                                                               &dcc->root));
 
        dc = (struct discard_cmd *)f2fs_lookup_rb_tree_ret(&dcc->root,
                                        NULL, start,