Bz #248176: GFS2: invalid metadata block, gfs2_meta_indirect_buffer
PATCH 1/1 Bz #248176: GFS2: invalid metadata block, gfs2_meta_indirect_buffer
Here is a set of five patches designed to fix the "invalid metadata block" and hang problems encountered when running the revolver test.
In order, the five patches are:
1. There were still some critical variables being manipulated outside the log_lock spinlock. That usually resulted in more hangs.
2. The list_move code previously concocted in log.c for bug #238162 (see https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=238162#c23)
seems to be causing a problem. That section was reverted. HOWEVER, I need to rerun the test cases listed in that bug to make sure removing it doesn't cause anything to break. I haven't had time yet.
3. The try_rgrp_unlink code in rgrp.c had an infinite loop. This was caused because the bitmap function rgblk_search can return a block less than the "goal" block, in which case it was looping. The fix is to make it always march forward as needed.
4. There was metadata corruption caused because the clone bitmaps weren't being kept in synch with the regular bitmaps in some cases. Code was added to keep them in synch.
5. Metadata corruption was occurring because page references weren't being removed in all cases. I previously added a function called detach_bufdata, but I discovered there already WAS a function out there to do the job. It's called gfs2_meta_cache_flush. So I added a call to that to remove the page references.
Recently I had been thinking that this was entirely unnecessary, but when I removed the code, the metadata corruption problem returned immediately. It might be that there is a timing window where the pages can be referenced before gfs2_meta_cache_flush is called and my patch cleans them up sooner.
PATCH 1/1 Bz #248176: GFS2: invalid metadata block, gfs2_meta_indirect_buffer
Hi,
None of these patches apply due to whitespace breakage.
Quoted 7 lines · Bob Peterson
Here is a set of five patches designed to fix the "invalid metadata block" and hang problems encountered when running the revolver test.
In order, the five patches are:
1. There were still some critical variables being manipulated outside the
log_lockspinlock. That usually resulted in more hangs.
The BUG_ON(!buffer_mapped()) line in this patch can be removed as its only debugging.
Quoted 5 lines
2. The
list_movecode previously concocted inlog.cfor bug #238162 (see https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=238162#c23)
seems to be causing a problem. That section was reverted. HOWEVER, I need to rerun the test cases listed in that bug to make sure removing it doesn't cause anything to break. I haven't had time yet.
Moving the assignment head = &sdp->sd_ail1_list; doesn't give us anything since head is a pointer and will be constant whether we have the lock or not.
Quoted 4 lines
3. The
try_rgrp_unlinkcode inrgrp.chad an infinite loop. This was caused because the bitmap functionrgblk_searchcan return a block less than the "goal" block, in which case it was looping. The fix is to make it always march forward as needed.
Ok.
Quoted 3 lines
4. There was metadata corruption caused because the clone bitmaps weren't being kept in synch with the regular bitmaps in some cases. Code was added to keep them in synch.
I need to look at this in more detail. You might be right, but its worth being rather careful in this part of the code.
Quoted 10 lines
5. Metadata corruption was occurring because page references weren't being removed in all cases. I previously added a function called
detach_bufdata, but I discovered there already WAS a function out there to do the job. It's calledgfs2_meta_cache_flush. So I added a call to that to remove the page references.
Recently I had been thinking that this was entirely unnecessary, but when I removed the code, the metadata corruption problem returned immediately. It might be that there is a timing window where the pages can be referenced beforegfs2_meta_cache_flushis called and my patch cleans them up sooner.
Yes, this looks good,
Steve.