ext4 xfstest regression due to ext4_es_lookup_extent

[Dmitry Monakhov <dmonakhov@openvz.org>]

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301'th xfstests are failed due to :
commit d100eef2440fea13e4f09e88b1c8bcbca64beb9f
Author: Zheng Liu <wenqing.lz@taobao.com>
Date:   Mon Feb 18 00:29:59 2013 -0500

    ext4: lookup block mapping in extent status tree

TESTCASE: https://github.com/dmonakhov/xfstests/commit/7b7efeee30a41109201e2040034e71db9b66ddc0

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 kernel BUG at fs/ext4/inode.c:1452!
 invalid opcode: 0000 [#1] SMP 
 Modules linked in: cpufreq_ondemand acpi_cpufreq freq_table mperf coretemp kvm_intel kvm crc32c_intel ghash_clmulni_intel microcode sg xhci_hcd button sd_mod crc_t10dif aesni_intel ablk_helper cryptd lrw aes\
l ahci libahci pata_acpi ata_generic dm_mirror dm_region_hash dm_log dm_mod
 CPU 2 
 Pid: 2142, comm: fio Not tainted 3.8.0-rc3+ #41                  /DQ67SW
 RIP: 0010:[<ffffffff81333c7b>]  [<ffffffff81333c7b>] mpage_da_submit_io+0x41b/0x5b0
 RSP: 0018:ffff8801c2837a48  EFLAGS: 00010202
 RAX: ffff880231e64bb0 RBX: ffff880231e64bb0 RCX: 0000000000000000
 RDX: 0000000000000003 RSI: 0000000000000001 RDI: ffffffff821372d8
 RBP: ffff8801c2837bb8 R08: ffff8801c2837df8 R09: 0000000000000001
 R10: ffff880231e64bb1 R11: 0000000000000003 R12: ffffea00076f5c28
 R13: 00000000000026d0 R14: ffff8801c2837be8 R15: 00000000000ea6d0
 FS:  00007fefeaeb5700(0000) GS:ffff88023d800000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007fefdf10299c CR3: 0000000209154000 CR4: 00000000000407e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
 Process fio (pid: 2142, threadinfo ffff8801c2836000, task ffff8801d3c48580)
 Stack:
  ffffffff82030f00 ffff8801c2837b58 ffff8801c2837df8 0000000000000000
  ffff880231e64bb1 0000000000000001 ffff880231e64bb0 000000002ba68688
  ffff8801c2837ae8 00000000000d4800 ffff880231f1cb98 00000000000026d0
 Call Trace:
  [<ffffffff81339769>] mpage_da_map_and_submit+0x369/0x3d0
  [<ffffffff81339acb>] write_cache_pages_da+0x1db/0x6f0
  [<ffffffff8133b07f>] ext4_da_writepages+0x49f/0x8b0
  [<ffffffff81105d9a>] ? __lock_acquire+0x4ca/0x560
  [<ffffffff811b4421>] do_writepages+0x51/0x70
  [<ffffffff8119fc24>] __filemap_fdatawrite_range+0x64/0x70
  [<ffffffff811a6a8b>] sys_fadvise64_64+0x25b/0x300
  [<ffffffff811a6b3e>] sys_fadvise64+0xe/0x10
  [<ffffffff818e9e99>] system_call_fastpath+0x16/0x1b
 Code: a0 fe ff ff 4c 8b 95 b0 fe ff ff 49 63 d1 48 83 c2 02 48 8b 34 d5 30 4c 2b 82 48 83 c6 01 45 85 c9 48 89 34 d5 30 4c 2b 82 74 04 <0f> 0b eb fe 41 0f b6 56 13 83 e2 01 48 63 f2 48 83 c6 02 48 8b 
 RIP  [<ffffffff81333c7b>] mpage_da_submit_io+0x41b/0x5b0
  RSP <ffff8801c2837a48>
 ---[ end trace 6f79fb4f46cf9f0e ]---
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Commit (d100eef2) this is very first commit where we try to make
extent-status-tree usefull. Definitely this is because cached value
is out of sync with real on-disk structure. I'll try to find out exact
place where this happen, but i'm shure this is just a beginning.
So Zheng please add sane self-testing infastructure for extent status
tree,  for example like follows:


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>From 65c5fc212b1c684c76899c6e5e1f24d88550c6fc Mon Sep 17 00:00:00 2001
From: Dmitry Monakhov <dmonakhov@openvz.org>
Date: Fri, 22 Feb 2013 20:55:52 +0400
Subject: [PATCH] ext4 add sanity ext4_es_lookup_extent

This patch does very simple thing: it recheck result returned from
ext4_es_lookup_extent() by comparing it old-good lookup via
ext4_{ind,ext}_map_blocks() under i_data_sem

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
---
 fs/ext4/inode.c |   42 ++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 42 insertions(+), 0 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 95a0c62..706db1f 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -482,6 +482,41 @@ static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
 	return num;
 }
 
+#define ES_AGGRESSIVE_TEST 1
+#ifdef ES_AGGRESSIVE_TEST
+void ext4_map_blocks_es_recheck(handle_t *handle, struct inode *inode,
+				struct ext4_map_blocks *es_map, int es_ret,
+				struct ext4_map_blocks *map, int flags)
+{
+	int ret;
+
+	map->m_flags = 0;
+	if (!(flags & EXT4_GET_BLOCKS_NO_LOCK))
+		down_read((&EXT4_I(inode)->i_data_sem));
+	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+		ret = ext4_ext_map_blocks(handle, inode, map, flags &
+					     EXT4_GET_BLOCKS_KEEP_SIZE);
+	} else {
+		ret = ext4_ind_map_blocks(handle, inode, map, flags &
+					     EXT4_GET_BLOCKS_KEEP_SIZE);
+	}
+	if (es_map->m_lblk != map->m_lblk ||
+	    es_map->m_flags != map->m_flags ||
+	    es_map->m_len != map->m_len ||
+	    es_map->m_pblk != map->m_pblk ||
+	    es_ret != ret) {
+		printk("Assertation failed for inode:%lu "
+		       "es_cached_ex [%d/%d/%llu/%x]:%d != "
+		       "found_ex [%d/%d/%llu/%x]:%d\n", inode->i_ino,
+		       es_map->m_lblk, es_map->m_len, es_map->m_pblk,
+		       es_map->m_flags, es_ret,
+		       map->m_lblk, map->m_len, map->m_pblk, map->m_flags, ret);
+		BUG();
+	}
+	if (!(flags & EXT4_GET_BLOCKS_NO_LOCK))
+		up_read((&EXT4_I(inode)->i_data_sem));
+}
+#endif
 /*
  * The ext4_map_blocks() function tries to look up the requested blocks,
  * and returns if the blocks are already mapped.
@@ -509,7 +544,11 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
 {
 	struct extent_status es;
 	int retval;
+#ifdef ES_AGGRESSIVE_TEST
+	struct ext4_map_blocks orig_map;
 
+	memcpy(&orig_map, map, sizeof(*map));
+#endif
 	map->m_flags = 0;
 	ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
 		  "logical block %lu\n", inode->i_ino, flags, map->m_len,
@@ -531,6 +570,9 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
 		} else {
 			BUG_ON(1);
 		}
+#ifdef ES_AGGRESSIVE_TEST
+		ext4_map_blocks_es_recheck(handle,inode, map, retval, &orig_map, flags);
+#endif
 		goto found;
 	}
 
-- 
1.7.1