Hi Neil, list,
I've been trying to get raid5 running for a while under the development
kernels, and have been failing since the early 2.5.30's. My current
failure scenario is back to what it was in 2.5.40 (the ll_rw_blk.c BUG has
hidden itself away again). This particular failure was created on a raid5
made out of 3 loop devices on regular files on an ext3 filesystem on a
single SCSI disk (script used to create this is below), but the exact same
failure occurs on a raid5 of 4 disk partitions on 4 scsi disks.
The current failure looks like:
1) all processes accessing the md stuck in D state
2) raid5d stuck in a cpu-gobbling loop, R state.
Kernel is 2.5.43 plus a patch (below) I needed to fs/block_dev.c to get
the raid device to open. System is SMP 2xPII 450, 1GB ram (highmem_4g),
adaptec aic7xxx.
Here are the pertinent pieces of sysrq-t (blktest is a throughput tester I
wrote a while back):
raid5d R DC90C938 0 3896 1 3893 (L-TLB)
Call Trace:
[<c01229b0>] tasklet_hi_action+0x80/0xd0
[<c0120068>] release_task+0x78/0x1c0
[<c02aa5af>] handle_stripe+0x2cf/0xf10
[<c01226ab>] do_softirq+0x5b/0xc0
[<c02a8a9d>] release_stripe+0x8d/0x130
[<c02ab729>] raid5d+0x139/0x600
[<c02b1a89>] md_thread+0x199/0x210
[<c0118fd0>] default_wake_function+0x0/0x40
[<c02b18f0>] md_thread+0x0/0x210
[<c01070d9>] kernel_thread_helper+0x5/0xc
blktest D EE1C9B68 0 4231 3744 4180 (L-TLB)
Call Trace:
[<c02a8e34>] get_active_stripe+0x144/0x360
[<c0118fd0>] default_wake_function+0x0/0x40
[<c02ab390>] raid5_unplug_device+0x1a0/0x400
[<c014d9ba>] bio_alloc+0x13a/0x1d0
[<c024f289>] generic_make_request+0x189/0x1a0
[<c024f33f>] submit_bio+0x9f/0xb0
[<c014bbd4>] __block_write_full_page+0x2c4/0x460
[<c014f610>] blkdev_writepage+0x0/0x20
[<c014f4e0>] blkdev_get_block+0x0/0x60
[<c014cf18>] block_write_full_page+0xe8/0x100
[<c014f4e0>] blkdev_get_block+0x0/0x60
[<c0109976>] apic_timer_interrupt+0x1a/0x20
[<c014f610>] blkdev_writepage+0x0/0x20
[<c014f61f>] blkdev_writepage+0xf/0x20
[<c014f4e0>] blkdev_get_block+0x0/0x60
[<c0167179>] mpage_writepages+0x2c9/0xb01
[<c0158ca1>] kill_fasync+0x31/0x4e
[<c023b7e6>] n_tty_receive_buf+0xe76/0xed0
[<c023b808>] n_tty_receive_buf+0xe98/0xed0
[<c014f610>] blkdev_writepage+0x0/0x20
[<c02e6e73>] tcp_v4_do_rcv+0x93/0x180
[<c013c00a>] __pagevec_free+0x1a/0x20
[<c01396b8>] release_pages+0x168/0x180
[<c010ae7a>] handle_IRQ_event+0x3a/0x60
[<c01336c6>] find_get_pages+0x36/0x80
[<c0139a8d>] pagevec_lookup+0x1d/0x24
[<c01465ca>] truncate_inode_pages+0x2fa/0x350
[<c0150811>] generic_writepages+0x11/0x15
[<c0145086>] do_writepages+0x16/0x30
[<c0132dcf>] filemap_fdatawrite+0x4f/0x60
[<c014a25b>] sync_blockdev+0x1b/0x40
[<c0150606>] blkdev_put+0x76/0x1a0
[<c0149d1b>] __fput+0x2b/0xf0
[<c0147f10>] filp_close+0xb0/0xc0
[<c01205db>] put_files_struct+0x4b/0xd0
[<c0120ffc>] do_exit+0x14c/0x370
[<c01324f1>] do_munmap+0x121/0x130
[<c0132544>] sys_munmap+0x44/0x70
[<c0108faf>] syscall_call+0x7/0xb
Here is the script I used to create the raid:
#!/bin/sh
DIR=/tmp
SIZE=64k
rm -f $DIR/md.pt1 $DIR/md.pt2 $DIR/md.pt3
dd if=/dev/zero of=$DIR/md.pt1 bs=1k count=$SIZE
dd if=/dev/zero of=$DIR/md.pt2 bs=1k count=$SIZE
dd if=/dev/zero of=$DIR/md.pt3 bs=1k count=$SIZE
losetup /dev/loop0 $DIR/md.pt1
losetup /dev/loop1 $DIR/md.pt2
losetup /dev/loop2 $DIR/md.pt3
cat >$DIR/raidtab.tst <<EOF
raiddev /dev/md0
raid-level 5
nr-raid-disks 3
nr-spare-disks 0
persistent-superblock 1
parity-algorithm left-symmetric
chunk-size 64k
device /dev/loop0
raid-disk 0
device /dev/loop1
raid-disk 1
device /dev/loop2
raid-disk 2
EOF
mkraid -c $DIR/raidtab.tst /dev/md0
Here is the patch to make the md open successfully:
--- linux-2.5.43/fs/block_dev.c Mon Sep 16 07:25:59 2002
+++ linux-currentish-vanilla/fs/block_dev.c Mon Sep 16 15:14:58 2002
@@ -612,12 +612,12 @@
if (owner)
__MOD_DEC_USE_COUNT(owner);
}
+
disk = get_gendisk(bdev->bd_dev, &part);
- if (!disk)
- goto out1;
+
if (!bdev->bd_contains) {
bdev->bd_contains = bdev;
- if (part) {
+ if (disk && part) {
struct block_device *whole;
whole = bdget(MKDEV(disk->major, disk->first_minor));
ret = -ENOMEM;
@@ -631,7 +631,7 @@
}
if (bdev->bd_contains == bdev) {
if (!bdev->bd_openers)
- bdev->bd_disk = disk;
+ bdev->bd_disk = disk;
if (!bdev->bd_queue) {
struct blk_dev_struct *p = blk_dev + major(dev);
bdev->bd_queue = &p->request_queue;
@@ -645,8 +645,12 @@
}
if (!bdev->bd_openers) {
struct backing_dev_info *bdi;
+ sector_t sect = 0;
+
bdev->bd_offset = 0;
- bd_set_size(bdev, (loff_t)get_capacity(disk) << 9);
+ if (disk)
+ sect = get_capacity(disk);
+ bd_set_size(bdev, (loff_t)sect << 9);
bdi = blk_get_backing_dev_info(bdev);
if (bdi == NULL)
bdi = &default_backing_dev_info;
--
/==============================\
| David Mansfield |
| [email protected] |
\==============================/