[Ocfs2-devel] Ocfs2-devel Digest, Vol 138, Issue 31 review

Zhangguanghui zhang.guanghui at h3c.com
Wed Oct 14 00:49:45 PDT 2015


OCFS2 is often used in high-availaibility systems, This patch enhances robustness for the filesystem.
but storage network is unstable,it still triggers a panic, such as ocfs2_start_trans -> __ocfs2_abort ->panic.
The 's_mount_opt' should depend on the mount option set, If errors=continue is set,
mark as a EIO error, change OCFS2_MOUNT_ERRORS_PANIC to OCFS2_MOUNT_ERRORS_CONT in __ocfs2_abort;
it's better than forcing a panic without decreasing availability,errors=continue seems be well to me.

Finally, any feedback about this process (positive or negative) would be greatly appreciated.

   Aug 11 11:32:25 cvknode73 kernel: [678904.787906] (pool,23256,12):ocfs2_start_trans:367 ERROR: status = -30
Aug 11 11:32:25 cvknode73 kernel: [678904.825046] CPU: 12 PID: 23256 Comm: pool Tainted: GF W IO 3.13.6 #1
Aug 11 11:32:25 cvknode73 kernel: [678904.825050] Hardware name: HP ProLiant BL460c G7, BIOS I27 12/03/2012
Aug 11 11:32:25 cvknode73 kernel: [678904.825054] ffffffffffffffe2 ffff88108c945a88 ffffffff81750690 ffff88180bacfff0
Aug 11 11:32:25 cvknode73 kernel: [678904.825064] ffff88174196d000 ffff88108c945ad8 ffffffffa052f667 ffffffffffffffe2
Aug 11 11:32:25 cvknode73 kernel: [678904.825072] 0000000000001000 ffff88108c945b58 ffff88175e870000 ffff8811ada4f000
Aug 11 11:32:25 cvknode73 kernel: [678904.825087] Call Trace:
Aug 11 11:32:25 cvknode73 kernel: [678904.825103] [<ffffffff81750690>] dump_stack+0x46/0x58
Aug 11 11:32:25 cvknode73 kernel: [678904.825154] [<ffffffffa052f667>] ocfs2_start_trans+0x1d7/0x200 [ocfs2]
Aug 11 11:32:25 cvknode73 kernel: [678904.825183] [<ffffffffa0505b60>] ocfs2_write_begin_nolock+0xda0/0x1c70 [ocfs2]
Aug 11 11:32:25 cvknode73 kernel: [678904.825216] [<ffffffffa052b7cb>] ? ocfs2_read_inode_block_full+0x3b/0x60 [ocfs2]
Aug 11 11:32:25 cvknode73 kernel: [678904.825248] [<ffffffffa051a82f>] ? ocfs2_inode_lock_full_nested+0x52f/0xc60 [ocfs2]
Aug 11 11:32:25 cvknode73 kernel: [678904.825277] [<ffffffffa0516060>] ? ocfs2_should_refresh_lock_res+0x80/0x190 [ocfs2]
Aug 11 11:32:25 cvknode73 kernel: [678904.825304] [<ffffffffa0506b36>] ocfs2_write_begin+0x106/0x230 [ocfs2]
Aug 11 11:32:25 cvknode73 kernel: [678904.825330] [<ffffffffa05180ab>] ? __ocfs2_cluster_unlock.isra.27+0x9b/0xe0 [ocfs2]
Aug 11 11:32:25 cvknode73 kernel: [678904.825342] [<ffffffff8115342b>] generic_file_buffered_write+0xfb/0x280
Aug 11 11:32:25 cvknode73 kernel: [678904.825370] [<ffffffffa051a1c5>] ? ocfs2_rw_lock+0x75/0x1b0 [ocfs2]
Aug 11 11:32:25 cvknode73 kernel: [678904.825398] [<ffffffffa0527f3f>] ocfs2_file_aio_write+0x79f/0x830 [ocfs2]
Aug 11 11:32:25 cvknode73 kernel: [678904.825407] [<ffffffff811c14ba>] do_sync_write+0x5a/0x90
Aug 11 11:32:25 cvknode73 kernel: [678904.825413] [<ffffffff811c1fc5>] vfs_write+0xc5/0x1f0
Aug 11 11:32:25 cvknode73 kernel: [678904.825418] [<ffffffff811c24c2>] SyS_write+0x52/0xa0
Aug 11 11:32:25 cvknode73 kernel: [678904.825426] [<ffffffff8176106d>] system_call_fastpath+0x1a/0x1f
Aug 11 11:32:25 cvknode73 kernel: [678904.825431] OCFS2: abort (device sdu): ocfs2_start_trans: Detected aborted journal

________________________________
zhangguanghui

Message: 8
Date: Fri, 28 Aug 2015 16:45:44 -0700
From: Mark Fasheh <mfasheh at suse.de>
Subject: Re: [Ocfs2-devel] [patch 04/28] ocfs2: add errors=continue
To: akpm at linux-foundation.org
Cc: ocfs2-devel at oss.oracle.com, rgoldwyn at suse.com
Message-ID: <20150828234544.GN1145 at wotan.suse.de>
Content-Type: text/plain; charset=us-ascii

On Wed, Aug 26, 2015 at 03:11:29PM -0700, Andrew Morton wrote:
> From: Goldwyn Rodrigues <rgoldwyn at suse.de>
> Subject: ocfs2: add errors=continue
>
> OCFS2 is often used in high-availaibility systems.  However, ocfs2
> converts the filesystem to read-only at the drop of the hat.  This may not
> be necessary, since turning the filesystem read-only would affect other
> running processes as well, decreasing availability.
>
> This attempt is to add errors=continue, which would return the EIO to the
> calling process and terminate furhter processing so that the filesystem is
> not corrupted further.  However, the filesystem is not converted to
> read-only.
>
> As a future plan, I intend to create a small utility or extend fsck.ocfs2
> to fix small errors such as in the inode.  The input to the utility such
> as the inode can come from the kernel logs so we don't have to schedule a
> downtime for fixing small-enough errors.
>
> The patch changes the ocfs2_error to return an error.  The error returned
> depends on the mount option set.  If none is set, the default is to turn
> the filesystem read-only.
>
> Perhaps errors=continue is not the best option name.  Historically it is
> used for making an attempt to progress in the current process itself.
> Should we call it errors=eio?  or errors=killproc?  Suggestions/Comments
> welcome.

errors=continue seems fine to me, thanks for this Goldwyn.


>
> Sources are available at:
> https://github.com/goldwynr/linux/tree/error-cont
>
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn at suse.com>
> Cc: Mark Fasheh <mfasheh at suse.com>
> Cc: Joel Becker <jlbec at evilplan.org>
> Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Reviewed-by: Mark Fasheh <mfasheh at suse.de>


> ---
>
>  fs/ocfs2/ocfs2.h |    2 +
>  fs/ocfs2/super.c |   59 ++++++++++++++++++++++++++++++++-------------
>  fs/ocfs2/super.h |    2 -
>  3 files changed, 45 insertions(+), 18 deletions(-)
>
> diff -puN fs/ocfs2/ocfs2.h~add-errors=continue fs/ocfs2/ocfs2.h
> --- a/fs/ocfs2/ocfs2.h~add-errors=continue
> +++ a/fs/ocfs2/ocfs2.h
> @@ -286,6 +286,8 @@ enum ocfs2_mount_options
>       OCFS2_MOUNT_HB_GLOBAL = 1 << 14, /* Global heartbeat */
>
>       OCFS2_MOUNT_JOURNAL_ASYNC_COMMIT = 1 << 15,  /* Journal Async Commit */
> +     OCFS2_MOUNT_ERRORS_CONT = 1 << 16, /* Return EIO to the calling process on error */
> +     OCFS2_MOUNT_ERRORS_ROFS = 1 << 17, /* Change filesystem to read-only on error */
>  };
>
>  #define OCFS2_OSB_SOFT_RO    0x0001
> diff -puN fs/ocfs2/super.c~add-errors=continue fs/ocfs2/super.c
> --- a/fs/ocfs2/super.c~add-errors=continue
> +++ a/fs/ocfs2/super.c
> @@ -192,6 +192,7 @@ enum {
>       Opt_resv_level,
>       Opt_dir_resv_level,
>       Opt_journal_async_commit,
> +     Opt_err_cont,
>       Opt_err,
>  };
>
> @@ -224,6 +225,7 @@ static const match_table_t tokens = {
>       {Opt_resv_level, "resv_level=%u"},
>       {Opt_dir_resv_level, "dir_resv_level=%u"},
>       {Opt_journal_async_commit, "journal_async_commit"},
> +     {Opt_err_cont, "errors=continue"},
>       {Opt_err, NULL}
>  };
>
> @@ -1330,10 +1332,19 @@ static int ocfs2_parse_options(struct su
>                       mopt->mount_opt |= OCFS2_MOUNT_NOINTR;
>                       break;
>               case Opt_err_panic:
> +                     mopt->mount_opt &= ~OCFS2_MOUNT_ERRORS_CONT;
> +                     mopt->mount_opt &= ~OCFS2_MOUNT_ERRORS_ROFS;
>                       mopt->mount_opt |= OCFS2_MOUNT_ERRORS_PANIC;
>                       break;
>               case Opt_err_ro:
> +                     mopt->mount_opt &= ~OCFS2_MOUNT_ERRORS_CONT;
>                       mopt->mount_opt &= ~OCFS2_MOUNT_ERRORS_PANIC;
> +                     mopt->mount_opt |= OCFS2_MOUNT_ERRORS_ROFS;
> +                     break;
> +             case Opt_err_cont:
> +                     mopt->mount_opt &= ~OCFS2_MOUNT_ERRORS_ROFS;
> +                     mopt->mount_opt &= ~OCFS2_MOUNT_ERRORS_PANIC;
> +                     mopt->mount_opt |= OCFS2_MOUNT_ERRORS_CONT;
>                       break;
>               case Opt_data_ordered:
>                       mopt->mount_opt &= ~OCFS2_MOUNT_DATA_WRITEBACK;
> @@ -1530,6 +1541,8 @@ static int ocfs2_show_options(struct seq
>
>       if (opts & OCFS2_MOUNT_ERRORS_PANIC)
>               seq_printf(s, ",errors=panic");
> +     else if (opts & OCFS2_MOUNT_ERRORS_CONT)
> +             seq_printf(s, ",errors=continue");
>       else
>               seq_printf(s, ",errors=remount-ro");
>
> @@ -2539,31 +2552,43 @@ static void ocfs2_delete_osb(struct ocfs
>       memset(osb, 0, sizeof(struct ocfs2_super));
>  }
>
> -/* Put OCFS2 into a readonly state, or (if the user specifies it),
> - * panic(). We do not support continue-on-error operation. */
> -static void ocfs2_handle_error(struct super_block *sb)
> +/* Depending on the mount option passed, perform one of the following:
> + * Put OCFS2 into a readonly state (default)
> + * Return EIO so that only the process errs
> + * Fix the error as if fsck.ocfs2 -y
> + * panic
> + */
> +static int ocfs2_handle_error(struct super_block *sb)
>  {
>       struct ocfs2_super *osb = OCFS2_SB(sb);
> +     int rv = 0;
> +
> +     ocfs2_set_osb_flag(osb, OCFS2_OSB_ERROR_FS);
> +     pr_crit("On-disk corruption discovered. "
> +             "Please run fsck.ocfs2 once the filesystem is unmounted.\n");
>
> -     if (osb->s_mount_opt & OCFS2_MOUNT_ERRORS_PANIC)
> +     if (osb->s_mount_opt & OCFS2_MOUNT_ERRORS_PANIC) {
>               panic("OCFS2: (device %s): panic forced after error\n",
>                     sb->s_id);
> +     } else if (osb->s_mount_opt & OCFS2_MOUNT_ERRORS_CONT) {
> +             pr_crit("OCFS2: Returning error to the calling process.\n");
> +             rv = -EIO;
> +     } else { /* default option */
> +             rv = -EROFS;
> +             if (sb->s_flags & MS_RDONLY &&
> +                             (ocfs2_is_soft_readonly(osb) ||
> +                              ocfs2_is_hard_readonly(osb)))
> +                     return rv;
>
> -     ocfs2_set_osb_flag(osb, OCFS2_OSB_ERROR_FS);
> -
> -     if (sb->s_flags & MS_RDONLY &&
> -         (ocfs2_is_soft_readonly(osb) ||
> -          ocfs2_is_hard_readonly(osb)))
> -             return;
> +             pr_crit("OCFS2: File system is now read-only.\n");
> +             sb->s_flags |= MS_RDONLY;
> +             ocfs2_set_ro_flag(osb, 0);
> +     }
>
> -     printk(KERN_CRIT "File system is now read-only due to the potential "
> -            "of on-disk corruption. Please run fsck.ocfs2 once the file "
> -            "system is unmounted.\n");
> -     sb->s_flags |= MS_RDONLY;
> -     ocfs2_set_ro_flag(osb, 0);
> +     return rv;
>  }
>
> -void __ocfs2_error(struct super_block *sb, const char *function,
> +int __ocfs2_error(struct super_block *sb, const char *function,
>                 const char *fmt, ...)
>  {
>       struct va_format vaf;
> @@ -2580,7 +2605,7 @@ void __ocfs2_error(struct super_block *s
>
>       va_end(args);
>
> -     ocfs2_handle_error(sb);
> +     return ocfs2_handle_error(sb);
>  }
>
>  /* Handle critical errors. This is intentionally more drastic than
> diff -puN fs/ocfs2/super.h~add-errors=continue fs/ocfs2/super.h
> --- a/fs/ocfs2/super.h~add-errors=continue
> +++ a/fs/ocfs2/super.h
> @@ -32,7 +32,7 @@ int ocfs2_publish_get_mount_state(struct
>                                 int node_num);
>
>  __printf(3, 4)
> -void __ocfs2_error(struct super_block *sb, const char *function,
> +int __ocfs2_error(struct super_block *sb, const char *function,
>                  const char *fmt, ...);
>
>  #define ocfs2_error(sb, fmt, args...) __ocfs2_error(sb, __PRETTY_FUNCTION__, fmt, ##args)
> _
--
Mark Fasheh



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