From: Dave Chinner <david@fromorbit.com>
To: xfs@oss.sgi.com
Subject: [PATCH 02/25] xfs: invalidate allocbt blocks moved to the free list
Date: Thu, 25 Oct 2012 17:33:51 +1100 [thread overview]
Message-ID: <1351146854-19343-3-git-send-email-david@fromorbit.com> (raw)
In-Reply-To: <1351146854-19343-1-git-send-email-david@fromorbit.com>
From: Dave Chinner <dchinner@redhat.com>
When we free a block from the alloc btree tree, we move it to the
freelist held in the AGFL and mark it busy in the busy extent tree.
This typically happens when we merge btree blocks.
Once the transaction is committed and checkpointed, the block can
remain on the free list for an indefinite amount of time. Now, this
isn't the end of the world at this point - if the free list is
shortened, the buffer is invalidated in the transaction that moves
it back to free space. If the buffer is allocated as metadata from
the free list, then all the modifications getted logged, and we have
no issues, either. And if it gets allocated as userdata direct from
the freelist, it gets invalidated and so will never get written.
However, during the time it sits on the free list, pressure on the
log can cause the AIL to be pushed and the buffer that covers the
block gets pushed for write. IOWs, we end up writing a freed
metadata block to disk. Again, this isn't the end of the world
because we know from the above we are only writing to free space.
The problem, however, is for validation callbacks. If the block was
on old btree root block, then the level of the block is going to be
higher than the current tree root, and so will fail validation.
There may be other inconsistencies in the block as well, and
currently we don't care because the block is in free space. Shutting
down the filesystem because a freed block doesn't pass write
validation, OTOH, is rather unfriendly.
So, make sure we always invalidate buffers as they move from the
free space trees to the free list so that we guarantee they never
get written to disk while on the free list.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_alloc_btree.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/xfs/xfs_alloc_btree.c b/fs/xfs/xfs_alloc_btree.c
index f1647ca..f7876c6 100644
--- a/fs/xfs/xfs_alloc_btree.c
+++ b/fs/xfs/xfs_alloc_btree.c
@@ -121,6 +121,8 @@ xfs_allocbt_free_block(
xfs_extent_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1,
XFS_EXTENT_BUSY_SKIP_DISCARD);
xfs_trans_agbtree_delta(cur->bc_tp, -1);
+
+ xfs_trans_binval(cur->bc_tp, bp);
return 0;
}
--
1.7.10
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next prev parent reply other threads:[~2012-10-25 6:32 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-25 6:33 [PATCH 00/25, V3] xfs: metadata buffer verifiers Dave Chinner
2012-10-25 6:33 ` [PATCH 01/25] xfs: growfs: don't read garbage for new secondary superblocks Dave Chinner
2012-10-30 0:17 ` Phil White
2012-10-25 6:33 ` Dave Chinner [this message]
2012-10-26 8:47 ` [PATCH 02/25] xfs: invalidate allocbt blocks moved to the free list Christoph Hellwig
2012-10-30 0:22 ` Phil White
2012-10-25 6:33 ` [PATCH 03/25] xfs: make buffer read verication an IO completion function Dave Chinner
2012-10-30 0:29 ` Phil White
2012-10-30 0:45 ` Dave Chinner
2012-10-30 0:55 ` Phil White
2012-10-25 6:33 ` [PATCH 04/25] xfs: uncached buffer reads need to return an error Dave Chinner
2012-10-26 8:48 ` Christoph Hellwig
2012-10-30 0:36 ` Phil White
2012-10-25 6:33 ` [PATCH 05/25] xfs: verify superblocks as they are read from disk Dave Chinner
2012-10-30 0:48 ` Phil White
2012-10-25 6:33 ` [PATCH 06/25] xfs: verify AGF blocks " Dave Chinner
2012-10-30 0:51 ` Phil White
2012-10-25 6:33 ` [PATCH 07/25] xfs: verify AGI " Dave Chinner
2012-10-30 0:53 ` Phil White
2012-10-30 22:13 ` Dave Chinner
2012-10-25 6:33 ` [PATCH 08/25] xfs: verify AGFL " Dave Chinner
2012-10-30 1:00 ` Phil White
2012-10-25 6:33 ` [PATCH 09/25] xfs: verify inode buffers " Dave Chinner
2012-10-30 1:06 ` Phil White
2012-10-25 6:33 ` [PATCH 10/25] xfs: verify btree blocks " Dave Chinner
2012-10-30 1:14 ` Phil White
2012-10-25 6:34 ` [PATCH 11/25] xfs: verify dquot " Dave Chinner
2012-10-30 1:36 ` Phil White
2012-10-25 6:34 ` [PATCH 12/25] xfs: add verifier callback to directory read code Dave Chinner
2012-10-30 3:15 ` Phil White
2012-10-25 6:34 ` [PATCH 13/25] xfs: factor dir2 block read operations Dave Chinner
2012-10-30 3:23 ` Phil White
2012-10-30 22:16 ` Dave Chinner
2012-10-25 6:34 ` [PATCH 14/25] xfs: verify dir2 block format buffers Dave Chinner
2012-10-30 3:26 ` Phil White
2012-10-25 6:34 ` [PATCH 15/25] xfs: factor dir2 free block reading Dave Chinner
2012-10-30 13:14 ` Phil White
2012-10-25 6:34 ` [PATCH 16/25] xfs: factor out dir2 data " Dave Chinner
2012-10-30 13:21 ` Phil White
2012-10-25 6:34 ` [PATCH 17/25] xfs: factor dir2 leaf read Dave Chinner
2012-10-30 13:22 ` Phil White
2012-10-25 6:34 ` [PATCH 18/25] xfs: factor and verify attr leaf reads Dave Chinner
2012-10-30 13:26 ` Phil White
2012-10-25 6:34 ` [PATCH 19/25] xfs: add xfs_da_node verification Dave Chinner
2012-10-30 13:30 ` Phil White
2012-10-30 22:23 ` Dave Chinner
2012-10-31 0:23 ` Phil White
2012-10-31 0:50 ` Dave Chinner
2012-10-25 6:34 ` [PATCH 20/25] xfs: Add verifiers to dir2 data readahead Dave Chinner
2012-10-30 13:31 ` Phil White
2012-10-25 6:34 ` [PATCH 21/25] xfs: add buffer pre-write callback Dave Chinner
2012-10-26 8:50 ` Christoph Hellwig
2012-10-30 22:30 ` Dave Chinner
2012-10-31 10:20 ` Christoph Hellwig
2012-10-30 13:32 ` Phil White
2012-10-25 6:34 ` [PATCH 22/25] xfs: add pre-write metadata buffer verifier callbacks Dave Chinner
2012-10-30 13:34 ` Phil White
2012-10-25 6:34 ` [PATCH 23/25] xfs: connect up write verifiers to new buffers Dave Chinner
2012-10-30 13:39 ` Phil White
2012-10-30 22:34 ` Dave Chinner
2012-10-25 6:34 ` [PATCH 24/25] xfs: convert buffer verifiers to an ops structure Dave Chinner
2012-10-30 13:41 ` Phil White
2012-10-25 6:34 ` [PATCH 25/25] xfs: add write verifiers to log recovery Dave Chinner
2012-10-26 8:54 ` Christoph Hellwig
2012-10-26 20:31 ` Dave Chinner
2012-10-30 12:23 ` Christoph Hellwig
2012-10-30 22:08 ` Dave Chinner
2012-10-31 10:19 ` Christoph Hellwig
2012-10-30 13:44 ` Phil White
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