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Go Back   Linux Archive > Redhat > Cluster Development

 
 
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Old 01-04-2011, 07:06 PM
 
Default dlm: send_bast_queue() skip list loop not only sending basts to convertqueue

From: Carlos Maiolino <cmaiolino@redhat.com>

with the current check condition: if (gr == lkb), the list will skip not only basts sent to convertqueue
since gr == lkb could be true on another situations, where such can cause a gfs2 corruption.

Corruption checked on gfs2 resource groups, adding a file on a node and removing the file on another node.
The resource groups got corrupted without this patch:

This is an output of the gfs2_edit without this patch:

Environment:
-a two node cluster
-gfs2 filesystem with 1G (counting journal space)
- /dev/sda5 1.0G 259M 766M 26% /mnt (new fs after mkfs.gfs2)

- A new filesystem shared by two nodes:

RG #1 located at: 65551 (0x1000f)
mh_magic 0x01161970(hex)
mh_type 2 0x2
mh_format 200 0xc8
rg_flags 0 0x0
rg_free 64858 0xfd5a
rg_dinodes 11 0xb

- After fill the filesystem with just one file (a 764M file using dd) from node 1

RG #1 located at: 65551 (0x1000f)
mh_magic 0x01161970(hex)
mh_type 2 0x2
mh_format 200 0xc8
rg_flags 0 0x0
rg_free 18 0x12
rg_dinodes 12 0xc

- After remove the file from the filesystem from node 2

RG #1 located at: 65551 (0x1000f)
mh_magic 0x01161970(hex)
mh_type 2 0x2
mh_format 200 0xc8
rg_flags 0 0x0
rg_free 18 0x12
rg_dinodes 12 0xc

- The space of the filesystem is not freed:

[root@node2-vm stats]# df -h /mnt
Filesystem Size Used Avail Use% Mounted on
/dev/sda 1.0G 1.0G 216K 100% /mnt

- The problem also persists after umount the filesystem

- Applying the patch, the problem is not reproducible anymore and the resource group blocks are properly freed

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
---
fs/dlm/lock.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 64e5f3e..565c519 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -1847,7 +1847,7 @@ static void send_bast_queue(struct dlm_rsb *r, struct list_head *head,

list_for_each_entry(gr, head, lkb_statequeue) {
/* skip self when sending basts to convertqueue */
- if (gr == lkb)
+ if (head == &r->res_grantqueue && gr == lkb)
continue;
if (gr->lkb_bastfn && modes_require_bast(gr, lkb)) {
queue_bast(r, gr, lkb->lkb_rqmode);
--
1.7.1
 

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