[Ocfs2-devel] [PATCH] ocfs2: fix BUG due to uncleaned localalloc during mount

[Junxiao Bi <junxiao.bi@oracle.com>]

Hi Joseph,

On 11/24/2015 09:38 PM, Joseph Qi wrote:
> Tariq has reported a BUG before and posted a fix at:
> https://oss.oracle.com/pipermail/ocfs2-devel/2015-April/010696.html
> 
> This is because during umount, localalloc shutdown relies on journal
> shutdown. But during journal shutdown, it just stops commit thread
> without checking its result. So it may happen that localalloc shutdown
> uncleaned during I/O error and after that, journal then has been marked
> clean if I/O restores.
The above is a storage issue. In this condition, io error can even
happen to journal commit, some transactions may have wrong data. Let fs
go without a fsck may cause corruption.
I am thinking whether we can fail the mount and mark the journal dirty
again. Then we can do fsck to it withoug a fsck patch.

Thanks,
Junxiao.

> Then during mount, localalloc won't be recovered because of clean
> journal and then trigger BUG when claiming clusters from localalloc.
> 
> In Tariq's fix, we have to run fsck offline and a separate fix to fsck
> is needed because it currently does not support clearing out localalloc
> inode. And my way to fix this issue is checking localalloc before
> actually loading it during mount. And this is somewhat online.
> 
> Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
> ---
>  fs/ocfs2/localalloc.c | 19 ++++++++++++-------
>  fs/ocfs2/localalloc.h |  2 +-
>  fs/ocfs2/super.c      | 17 ++++++++++++++---
>  3 files changed, 27 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/ocfs2/localalloc.c b/fs/ocfs2/localalloc.c
> index 0a4457f..ceebaef 100644
> --- a/fs/ocfs2/localalloc.c
> +++ b/fs/ocfs2/localalloc.c
> @@ -281,7 +281,7 @@ bail:
>  	return ret;
>  }
> 
> -int ocfs2_load_local_alloc(struct ocfs2_super *osb)
> +int ocfs2_load_local_alloc(struct ocfs2_super *osb, int check, int *recovery)
>  {
>  	int status = 0;
>  	struct ocfs2_dinode *alloc = NULL;
> @@ -345,21 +345,26 @@ int ocfs2_load_local_alloc(struct ocfs2_super *osb)
>  	if (num_used
>  	    || alloc->id1.bitmap1.i_used
>  	    || alloc->id1.bitmap1.i_total
> -	    || la->la_bm_off)
> +	    || la->la_bm_off) {
>  		mlog(ML_ERROR, "Local alloc hasn't been recovered!\n"
>  		     "found = %u, set = %u, taken = %u, off = %u\n",
>  		     num_used, le32_to_cpu(alloc->id1.bitmap1.i_used),
>  		     le32_to_cpu(alloc->id1.bitmap1.i_total),
>  		     OCFS2_LOCAL_ALLOC(alloc)->la_bm_off);
> +		status = -EINVAL;
> +		*recovery = 1;
> +		goto bail;
> +	}
> 
> -	osb->local_alloc_bh = alloc_bh;
> -	osb->local_alloc_state = OCFS2_LA_ENABLED;
> +	if (!check) {
> +		osb->local_alloc_bh = alloc_bh;
> +		osb->local_alloc_state = OCFS2_LA_ENABLED;
> +	}
> 
>  bail:
> -	if (status < 0)
> +	if (status < 0 || check)
>  		brelse(alloc_bh);
> -	if (inode)
> -		iput(inode);
> +	iput(inode);
> 
>  	trace_ocfs2_load_local_alloc(osb->local_alloc_bits);
> 
> diff --git a/fs/ocfs2/localalloc.h b/fs/ocfs2/localalloc.h
> index 44a7d1f..a913841 100644
> --- a/fs/ocfs2/localalloc.h
> +++ b/fs/ocfs2/localalloc.h
> @@ -26,7 +26,7 @@
>  #ifndef OCFS2_LOCALALLOC_H
>  #define OCFS2_LOCALALLOC_H
> 
> -int ocfs2_load_local_alloc(struct ocfs2_super *osb);
> +int ocfs2_load_local_alloc(struct ocfs2_super *osb, int check, int *recovery);
> 
>  void ocfs2_shutdown_local_alloc(struct ocfs2_super *osb);
> 
> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
> index 2de4c8a..4004b29 100644
> --- a/fs/ocfs2/super.c
> +++ b/fs/ocfs2/super.c
> @@ -2428,6 +2428,7 @@ static int ocfs2_check_volume(struct ocfs2_super *osb)
>  	int status;
>  	int dirty;
>  	int local;
> +	int la_dirty = 0, recovery = 0;
>  	struct ocfs2_dinode *local_alloc = NULL; /* only used if we
>  						  * recover
>  						  * ourselves. */
> @@ -2449,6 +2450,16 @@ static int ocfs2_check_volume(struct ocfs2_super *osb)
>  	 * recover anything. Otherwise, journal_load will do that
>  	 * dirty work for us :) */
>  	if (!dirty) {
> +		/* It may happen that local alloc is unclean shutdown, but
> +		 * journal has been marked clean, so check it here and do
> +		 * recovery if needed */
> +		status = ocfs2_load_local_alloc(osb, 1, &recovery);
> +		if (recovery) {
> +			printk(KERN_NOTICE "ocfs2: local alloc needs recovery "
> +					"on device (%s).\n", osb->dev_str);
> +			la_dirty = 1;
> +		}
> +
>  		status = ocfs2_journal_wipe(osb->journal, 0);
>  		if (status < 0) {
>  			mlog_errno(status);
> @@ -2477,7 +2488,7 @@ static int ocfs2_check_volume(struct ocfs2_super *osb)
>  				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
>  				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
> 
> -	if (dirty) {
> +	if (dirty || la_dirty) {
>  		/* recover my local alloc if we didn't unmount cleanly. */
>  		status = ocfs2_begin_local_alloc_recovery(osb,
>  							  osb->slot_num,
> @@ -2490,13 +2501,13 @@ static int ocfs2_check_volume(struct ocfs2_super *osb)
>  		 * ourselves as mounted. */
>  	}
> 
> -	status = ocfs2_load_local_alloc(osb);
> +	status = ocfs2_load_local_alloc(osb, 0, &recovery);
>  	if (status < 0) {
>  		mlog_errno(status);
>  		goto finally;
>  	}
> 
> -	if (dirty) {
> +	if (dirty || la_dirty) {
>  		/* Recovery will be completed after we've mounted the
>  		 * rest of the volume. */
>  		osb->dirty = 1;
>