Re: [PATCH v3 0/8] speculative preallocation inode tracking

From: Ben Myers <bpm@sgi.com>
To: Brian Foster <bfoster@redhat.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH v3 0/8] speculative preallocation inode tracking
Date: Wed, 26 Sep 2012 10:39:13 -0500	[thread overview]
Message-ID: <20120926153912.GC13214@sgi.com> (raw)
In-Reply-To: <20120926151923.GB13214@sgi.com>

Hey Brian,

On Wed, Sep 26, 2012 at 10:19:23AM -0500, Ben Myers wrote:
> On Fri, Sep 14, 2012 at 08:19:47AM -0400, Brian Foster wrote:
> > This is v3 of the speculative preallocation inode tracking patchset. This
> > functionality tracks inodes with post-EOF speculative preallocation for the
> > purpose of background and on-demand trimming.
> > 
> > Background scanning occurs on a longish interval (5 minutes by default) and in
> > a best-effort mode (i.e., inodes are skipped due to lock contention or dirty
> > cache). The intent is to clear up post-EOF blocks on inodes that might have
> > allocations hanging around due to open-write-close sequences (NFS).
> > 
> > On demand scanning is provided via a new ioctl and supports various parameters
> > such as scan mode, filtering by quota id and minimum file size. A pending use
> > case for on demand scanning is for accurate quota accounting via the gluster
> > scale out filesystem (i.e., to free up preallocated space when near a usage
> > limit).

Maybe it would help if I would give you some context!  I was running your patch
set along side with the inode64 related patch set from Carlos on an i386 box
and hit this assert on two subsequent test runs... both happened to be in test
133 at the time of the crash.

Regards,
	Ben

> [33084.794491] XFS (sda2): Ending clean mount
> [33170.400045] XFS: Assertion failed: !atomic_read(&VFS_I(ip)->i_count) || xfs_isilocked(ip, XFS_IOLOCK_EXCL), file: /root/xfs/fs/xfs/xfs_inode.c, line: 1128
> [33170.41422[    0.000000] Initializing cgroup subsys cpuset
> [    0.000000] Initializing cgroup subsys cpu
> [    0.000000] Linux version 3.6.0-rc1-1.2-desktop+ (root@nfs7) (gcc version 4.6.2 (SUSE Linux) ) #26 SMP PREEMPT Fri Sep 21 18:26:16 CDT 2012
> [    0.000000] e820: BIOS-provided physical RAM map:
> [    0.000000] BIOS-e820: [mem 0x0000000000000100-0x000000000009fbff] usable
> 
> crash> bt
> PID: 1289   TASK: f38d71d0  CPU: 1   COMMAND: "kworker/1:2"
>  #0 [f17c9b88] crash_kexec at c0295045
>  #1 [f17c9be0] oops_end at c06ab2f2
>  #2 [f17c9bf8] die at c020539a
>  #3 [f17c9c10] do_trap at c06aadc1
>  #4 [f17c9c28] do_invalid_op at c0202eb1
>  #5 [f17c9cc4] error_code (via invalid_op) at c06aab7c
>     EAX: 0000008e  EBX: ec3d9400  ECX: 0000071e  EDX: 00000046  EBP: f17c9d18 
>     DS:  007b      ESI: ec3d9400  ES:  007b      EDI: ef973d00  GS:  2e30
>     CS:  0060      EIP: f9d1dbb6  ERR: ffffffff  EFLAGS: 00010292 
>  #6 [f17c9cf8] assfail at f9d1dbb6 [xfs]
>  #7 [f17c9d1c] xfs_itruncate_extents at f9d6335f [xfs]
>  #8 [f17c9d98] xfs_free_eofblocks at f9d237d9 [xfs]
>  #9 [f17c9df8] xfs_inode_free_eofblocks at f9d221b4 [xfs]
> #10 [f17c9e14] xfs_inode_ag_walk at f9d20ab9 [xfs]
> #11 [f17c9ee4] xfs_inode_ag_iterator_tag at f9d20d6b [xfs]
> #12 [f17c9f18] xfs_inodes_free_eofblocks at f9d21c95 [xfs]
> #13 [f17c9f34] xfs_eofblocks_worker at f9d21cc3 [xfs]
> #14 [f17c9f40] process_one_work at c0251ea5
> #15 [f17c9f84] worker_thread at c0252504
> #16 [f17c9fbc] kthread at c025672b
> #17 [f17c9fe8] kernel_thread_helper at c06b06f4
> 
> It seems that test 133 was running at the time of the crash in two cases.  This
> is a neat patch set but we need to resolve this before pulling it in.
> 
> Regards,
> Ben
> 
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