From: Dave Chinner <david@fromorbit.com>
To: xfs@oss.sgi.com
Subject: ***** SUSPECTED SPAM ***** [RFD 01/17] xfs: inode allocation tickets
Date: Mon, 12 Aug 2013 23:19:51 +1000 [thread overview]
Message-ID: <1376313607-28133-2-git-send-email-david@fromorbit.com> (raw)
In-Reply-To: <1376313607-28133-1-git-send-email-david@fromorbit.com>
From: Dave Chinner <dchinner@redhat.com>
If we want to split inode allocation up into a background chunk allocator and an
indvidual free inode allocator, then we need to be able to guarantee that a free
inode will be available before we take a log reservation for the free inode
allocation.
If we don't guarantee that we can allocate an inode before we reserve log space
for the individual inode allocation, then we may reserve all the remaining log
space for the free inode allocation and then not be able to reserve space for
a ne winode chunk allocation in the log. This will cause an inode allocation
deadlock.
To avoid this deadlock, use a ticket system to guarantee an allocation has a
reserved free inode before it proceeds to the transaction reservation for the
allocation. This allows the free inode allocation to block waiting for
background allocation to allocate more inode chunks in a sane and rational
manner.
The ticket system needs to be a per-allocation group ticket, as inodes are
allocated and tracked at a per-AG granularity. Hence we need to restructure the
inode allocation code to select an AG for the new inode as early as possible
and then take a ticket on that AG. It is entirely possible that we can then get
an ENOSPC error for the inode chunk allocation, so we must be able to fall all
the way back to this ticket allocation loop to try another AG in this case.
Hauling this AG selection loop out of the internal free inode allocation code
might be sufficiently complex to warrant multiple setup patches by itself....
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_ialloc.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/xfs/xfs_ialloc.h b/fs/xfs/xfs_ialloc.h
index 68c0732..1da16f5 100644
--- a/fs/xfs/xfs_ialloc.h
+++ b/fs/xfs/xfs_ialloc.h
@@ -24,6 +24,8 @@ struct xfs_imap;
struct xfs_mount;
struct xfs_trans;
+struct xfs_ialloc_ticket;
+
/*
* Allocation parameters for inode allocation.
*/
--
1.8.3.2
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next prev parent reply other threads:[~2013-08-12 13:20 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-12 13:19 ***** SUSPECTED SPAM ***** [RFD 00/17] xfs: inode management development direction Dave Chinner
2013-08-12 13:19 ` Dave Chinner [this message]
2013-08-12 13:19 ` ***** SUSPECTED SPAM ***** [RFD 02/17] xfs: separate inode chunk allocation from free inode allocation Dave Chinner
2013-08-12 13:19 ` ***** SUSPECTED SPAM ***** [RFD 03/17] xfs: move inode chunk allocation into a workqueue Dave Chinner
2013-08-12 13:19 ` ***** SUSPECTED SPAM ***** [RFD 04/17] xfs: optimise background inode chunk allocation Dave Chinner
2013-08-12 13:19 ` ***** SUSPECTED SPAM ***** [RFD 05/17] xfs: introduce a free inode allocation btree Dave Chinner
2013-08-12 13:19 ` ***** SUSPECTED SPAM ***** [RFD 06/17] xfs: partial inode chunk allocation Dave Chinner
2013-08-13 22:07 ` Brian Foster
2013-08-12 13:19 ` ***** SUSPECTED SPAM ***** [RFD 07/17] xfs: separate inode chunk freeing from inode freeing Dave Chinner
2013-08-12 13:19 ` ***** SUSPECTED SPAM ***** [RFD 08/17] xfs: inode chunk freeing in the background Dave Chinner
2013-08-12 13:19 ` ***** SUSPECTED SPAM ***** [RFD 09/17] xfs: optimise inode chunk freeing Dave Chinner
2013-08-12 13:20 ` ***** SUSPECTED SPAM ***** [RFD 10/17] xfs: swap extents operations for CRC filesystems Dave Chinner
2013-08-12 13:20 ` ***** SUSPECTED SPAM ***** [RFD 11/17] xfs: factor xfs_create to prepare for O_TMPFILE Dave Chinner
2013-08-20 8:16 ` Zhi Yong Wu
2013-11-06 11:20 ` Christoph Hellwig
2013-11-06 11:21 ` Christoph Hellwig
2013-08-12 13:20 ` ***** SUSPECTED SPAM ***** [RFD 12/17] xfs: add tmpfile methods Dave Chinner
2013-08-12 13:20 ` ***** SUSPECTED SPAM ***** [RFD 13/17] xfs: allow linkat() on O_TMPFILE files Dave Chinner
2013-08-12 13:20 ` ***** SUSPECTED SPAM ***** [RFD 14/17] xfs: separate inode freeing from inactivation Dave Chinner
2013-08-12 13:20 ` ***** SUSPECTED SPAM ***** [RFD 15/17] xfs: introduce a method vector for unlinked list operations Dave Chinner
2013-08-12 13:20 ` ***** SUSPECTED SPAM ***** [RFD 16/17] xfs: add in-core unlinked list for v3 inodes Dave Chinner
2013-08-12 13:20 ` ***** SUSPECTED SPAM ***** [RFD 17/17] xfs: log unlinked list modifications in the incore v3 inode Dave Chinner
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