From: Li Zhong <lizhongfs@gmail.com>
To: linux-ext4@vger.kernel.org
Cc: tytso@mit.edu, adilger.kernel@dilger.ca
Subject: [RFC PATCH] ext4: Fix group number calculation
Date: Fri, 05 Jul 2013 17:29:48 +0800 [thread overview]
Message-ID: <1373016588.2939.15.camel@ThinkPad-T5421> (raw)
This patch tries to fix the following BUG:
[ 568.877799] ------------[ cut here ]------------
[ 568.877833] kernel BUG at fs/ext4/mballoc.c:3728!
[ 568.877840] Oops: Exception in kernel mode, sig: 5 [#1]
[ 568.877845] SMP NR_CPUS=32 NUMA pSeries
[ 568.877852] Modules linked in: binfmt_misc
[ 568.877861] CPU: 1 PID: 3516 Comm: fs_mark Not tainted 3.10.0-03216-g7c6809f-dirty #1
[ 568.877867] task: c0000001fb0b8000 ti: c0000001fa954000 task.ti: c0000001fa954000
[ 568.877873] NIP: c0000000002f42a4 LR: c0000000002f4274 CTR: c000000000317ef8
[ 568.877879] REGS: c0000001fa956ed0 TRAP: 0700 Not tainted (3.10.0-03216-g7c6809f-dirty)
[ 568.877884] MSR: 8000000000029032 <SF,EE,ME,IR,DR,RI> CR: 24000428 XER: 00000000
[ 568.877902] SOFTE: 1
[ 568.877905] CFAR: c0000000002b5464
[ 568.877908]
GPR00: 0000000000000001 c0000001fa957150 c000000000c6a408 c0000001fb588000
GPR04: 0000000000003fff c0000001fa9571c0 c0000001fa9571c4 000138098c50625f
GPR08: 1301200000000000 0000000000000002 0000000000000001 0000000000000000
GPR12: 0000000024000422 c00000000f33a300 0000000000008000 c0000001fa9577f0
GPR16: c0000001fb7d0100 c000000000c29190 c0000000007f46e8 c000000000a14672
GPR20: 0000000000000001 0000000000000008 ffffffffffffffff 0000000000000000
GPR24: 0000000000000100 c0000001fa957278 c0000001fdb2bc78 c0000001fa957288
GPR28: 0000000000100100 c0000001fa957288 c0000001fb588000 c0000001fdb2bd10
[ 568.877993] NIP [c0000000002f42a4] .ext4_mb_release_group_pa+0xec/0x1c0
[ 568.877999] LR [c0000000002f4274] .ext4_mb_release_group_pa+0xbc/0x1c0
[ 568.878004] Call Trace:
[ 568.878008] [c0000001fa957150] [c0000000002f4274] .ext4_mb_release_group_pa+0xbc/0x1c0 (unreliable)
[ 568.878017] [c0000001fa957200] [c0000000002fb070] .ext4_mb_discard_lg_preallocations+0x394/0x444
[ 568.878025] [c0000001fa957340] [c0000000002fb45c] .ext4_mb_release_context+0x33c/0x734
[ 568.878032] [c0000001fa957440] [c0000000002fbcf8] .ext4_mb_new_blocks+0x4a4/0x5f4
[ 568.878039] [c0000001fa957510] [c0000000002ef56c] .ext4_ext_map_blocks+0xc28/0x1178
[ 568.878047] [c0000001fa957640] [c0000000002c1a94] .ext4_map_blocks+0x2c8/0x490
[ 568.878054] [c0000001fa957730] [c0000000002c536c] .ext4_writepages+0x738/0xc60
[ 568.878062] [c0000001fa957950] [c000000000168a78] .do_writepages+0x5c/0x80
[ 568.878069] [c0000001fa9579d0] [c00000000015d1c4] .__filemap_fdatawrite_range+0x88/0xb0
[ 568.878078] [c0000001fa957aa0] [c00000000015d23c] .filemap_write_and_wait_range+0x50/0xfc
[ 568.878085] [c0000001fa957b30] [c0000000002b8edc] .ext4_sync_file+0x220/0x3c4
[ 568.878092] [c0000001fa957be0] [c0000000001f849c] .vfs_fsync_range+0x64/0x80
[ 568.878098] [c0000001fa957c70] [c0000000001f84f0] .vfs_fsync+0x38/0x4c
[ 568.878105] [c0000001fa957d00] [c0000000001f87f4] .do_fsync+0x54/0x90
[ 568.878111] [c0000001fa957db0] [c0000000001f8894] .SyS_fsync+0x28/0x3c
[ 568.878120] [c0000001fa957e30] [c000000000009c88] syscall_exit+0x0/0x7c
[ 568.878125] Instruction dump:
[ 568.878130] 60000000 813d0034 81610070 38000000 7f8b4800 419e001c 813f007c 7d2bfe70
[ 568.878144] 7d604a78 7c005850 54000ffe 7c0007b4 <0b000000> e8a10076 e87f0090 7fa4eb78
[ 568.878160] ---[ end trace 594d911d9654770b ]---
It seems that it is caused by different group numbers calculated from
ext4_get_group_number() and ext4_get_group_no_and_offset().
The fix below tries to make ext4_get_group_number() consistent with
ext4_get_group_no_and_offset():
1) minus first data block number instead of adding it
2) remove the cluster bits, as seems it is used for offset calculation in
ext4_get_group_no_and_offset().
Signed-off-by: Li Zhong <lizhongfs@gmail.com>
---
fs/ext4/balloc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 5833939..938c97e 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -38,9 +38,9 @@ ext4_group_t ext4_get_group_number(struct super_block *sb,
ext4_group_t group;
if (test_opt2(sb, STD_GROUP_SIZE))
- group = (le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) +
- block) >>
- (EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3);
+ group = (block -
+ le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >>
+ (EXT4_BLOCK_SIZE_BITS(sb) + 3);
else
ext4_get_group_no_and_offset(sb, block, &group, NULL);
return group;
--
1.7.9.5
next reply other threads:[~2013-07-05 9:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-05 9:29 Li Zhong [this message]
2013-07-06 3:11 ` [RFC PATCH] ext4: Fix group number calculation Theodore Ts'o
2013-07-07 0:14 ` Li Zhong
2013-07-08 6:25 ` Lukáš Czerner
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