Re: [PATCH 4/10] xfs: implement xfs_perag_inumbers

[Jeff Liu <jeff.liu@oracle.com>]

As per the discussion with Brain in "[PATCH 3/10] xfs: consolidate xfs_inumbers",

Please ignore this patch since it need a distinct fix.

Thanks,
-Jeff

On 12/28 2013 19:20 PM, Jeff Liu wrote:
> From: Jie Liu <jeff.liu@oracle.com>
> 
> Introduce xfs_perag_inumbers(), it could be used to fetch inode inode
> number tables per allocation group via a new ioctl(2) in the future.
> Also, that would be a net win considering the scalability for a file
> system with huge number of inodes as multiple allocation groups can be
> scanned in parallel.
> 
> Refactor xfs_inumbers() with it.
> 
> Signed-off-by: Jie Liu <jeff.liu@oracle.com>
> ---
>  fs/xfs/xfs_itable.c | 175 +++++++++++++++++++++++++++++++++-------------------
>  fs/xfs/xfs_itable.h |  13 +++-
>  2 files changed, 121 insertions(+), 67 deletions(-)
> 
> diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c
> index 4d262f6..b890d1f 100644
> --- a/fs/xfs/xfs_itable.c
> +++ b/fs/xfs/xfs_itable.c
> @@ -569,51 +569,42 @@ xfs_inumbers_fmt(
>  }
>  
>  /*
> - * Return inode number table for the filesystem.
> + * Return inode number table in an allocation group.  Record how many elements
> + * have been written out and update the last allocation group inode number on
> + * success.  Otherwise, those values will remain the same and return error.
>   */
> -int					/* error status */
> -xfs_inumbers(
> -	struct xfs_mount	*mp,/* mount point for filesystem */
> -	xfs_ino_t		*lastino,/* last inode returned */
> -	int			*count,/* size of buffer/count returned */
> -	void			__user *ubuffer,/* buffer with inode desc */
> +static int
> +xfs_perag_inumbers(
> +	struct xfs_mount	*mp,
> +	struct xfs_aginumbers	*aip,
> +	struct xfs_inogrp	*buffer,
> +	int			bcount,
>  	inumbers_fmt_pf		formatter)
>  {
> -	xfs_agnumber_t		agno = XFS_INO_TO_AGNO(mp, *lastino);
> -	xfs_agino_t		agino = XFS_INO_TO_AGINO(mp, *lastino);
> -	int			left = *count;
> -	struct xfs_btree_cur	*cur = NULL;
> -	struct xfs_buf		*agbp = NULL;
> -	struct xfs_inogrp	*buffer;
> -	int			bcount;
> -	int			bufidx;
> +	xfs_agnumber_t		agno = aip->ai_agno;
> +	xfs_agino_t		agino = *(aip->ai_lastip);
> +	char			*ubuffer = aip->ai_ubuffer;
> +	int			ubleft = aip->ai_icount;
> +	int			bufidx = 0;
> +	long			count = 0;/* # elements written out */
> +	struct xfs_agi		*agi;
> +	struct xfs_buf		*agbp;
> +	struct xfs_btree_cur	*cur;
>  	int			error;
>  
> -	*count = 0;
> -	if (agno >= mp->m_sb.sb_agcount ||
> -	    *lastino != XFS_AGINO_TO_INO(mp, agno, agino))
> -		return 0;
> -
> -	bcount = MIN(left, (int)(PAGE_SIZE / sizeof(*buffer)));
> -	buffer = kmem_alloc(bcount * sizeof(*buffer), KM_SLEEP);
> -	bufidx = error = 0;
> -	do {
> +	error = xfs_ialloc_read_agi(mp, NULL, agno, &agbp);
> +	if (error)
> +		return error;
> +	agi = XFS_BUF_TO_AGI(agbp);
> +	cur = xfs_inobt_init_cursor(mp, NULL, agbp, agno);
> +	for (;;) {
>  		struct xfs_inobt_rec_incore	r;
>  		int				stat;
>  
> -		if (!agbp) {
> -			error = xfs_ialloc_read_agi(mp, NULL, agno, &agbp);
> -			if (error)
> -				break;
> -			cur = xfs_inobt_init_cursor(mp, NULL, agbp, agno);
> -		}
> +		/* Done if failed to lookup or no inode chuck is found */
>  		error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_GE, &stat);
> -		if (error)
> +		if (error || stat == 0)
>  			break;
> -		if (!stat) {
> -			/* Done, proceed to look up the next AG */
> -			goto next_ag;
> -		}
>  
>  		error = xfs_inobt_get_rec(cur, &r, &stat);
>  		if (error)
> @@ -621,59 +612,113 @@ xfs_inumbers(
>  		XFS_WANT_CORRUPTED_GOTO(stat == 1, error0);
>  
>  		agino = r.ir_startino + XFS_INODES_PER_CHUNK - 1;
> -		buffer[bufidx].xi_startino =
> -			XFS_AGINO_TO_INO(mp, agno, r.ir_startino);
> -		buffer[bufidx].xi_alloccount =
> -			XFS_INODES_PER_CHUNK - r.ir_freecount;
> +		buffer[bufidx].xi_startino = XFS_AGINO_TO_INO(mp, agno,
> +							      r.ir_startino);
> +		buffer[bufidx].xi_alloccount = XFS_INODES_PER_CHUNK -
> +					       r.ir_freecount;
>  		buffer[bufidx].xi_allocmask = ~r.ir_free;
> -		if (++bufidx == bcount) {
> +		/* Run out of the given buffer range, it's time to write out */
> +		if (++bufidx == ubleft) {
>  			long	written;
> +
>  			error = formatter(ubuffer, buffer, bufidx, &written);
>  			if (error)
>  				break;
>  			ubuffer += written;
> -			*count += bufidx;
> +			count += bufidx;
>  			bufidx = 0;
>  		}
> -		if (!--left)
> +		if (!--ubleft)
>  			break;
>  
>  		error = xfs_btree_increment(cur, 0, &stat);
> -		if (error)
> +		if (error || stat == 0) {
> +			/* Done if failed or there are no rightward entries */
>  			break;
> -		if (stat) {
> -			/*
> -			 * The agino value has already been bumped, just try
> -			 * to skip up to it.
> -			 */
> -			agino += XFS_INODES_PER_CHUNK;
> -			continue;
>  		}
>  
> -next_ag:
> -		xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
> -		cur = NULL;
> -		xfs_buf_relse(agbp);
> -		agbp = NULL;
> -		agino = 0;
> -	} while (++agno < mp->m_sb.sb_agcount);
> +		/*
> +		 * The agino value has already been bumped.  Just try to skip
> +		 * up to it.
> +		 */
> +		agino += XFS_INODES_PER_CHUNK;
> +	}
>  
>  	if (!error) {
> +		/*
> +		 * There might have remaining inode number tables reside in
> +		 * buffer which have not yet been written out if we iterate
> +		 * beyond inode btree.  We need to handle them separately.
> +		 */
>  		if (bufidx) {
>  			long	written;
> +
>  			error = formatter(ubuffer, buffer, bufidx, &written);
> -			if (!error)
> -				*count += bufidx;
> +			if (error)
> +				goto error0;
> +			count += bufidx;
>  		}
> -		*lastino = XFS_AGINO_TO_INO(mp, agno, agino);
> +		/* Update the last AG inode number */
> +		*(aip->ai_lastip) = agino;
> +		/* Record how many elements have been written out */
> +		aip->ai_ocount = count;
>  	}
>  
>  error0:
> +	xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
> +	xfs_buf_relse(agbp);
> +
> +	return error;
> +}
> +
> +/* Return inode number table for the filesystem */
> +int
> +xfs_inumbers(
> +	struct xfs_mount	*mp,/* mount point for filesystem */
> +	xfs_ino_t		*lastinop,/* last inode returned */
> +	int			*ubcountp,/* size of buffer/count returned */
> +	void			__user *ubuffer,/* buffer with inode desc */
> +	inumbers_fmt_pf		formatter)
> +{
> +	xfs_agnumber_t		agno = XFS_INO_TO_AGNO(mp, *lastinop);
> +	xfs_agino_t		agino = XFS_INO_TO_AGINO(mp, *lastinop);
> +	int			ubleft = *ubcountp;
> +	struct xfs_inogrp	*buffer;
> +	int			count;
> +	int			error;
> +
> +	*ubcountp = 0;
> +	if (agno >= mp->m_sb.sb_agcount ||
> +	    *lastinop != XFS_AGINO_TO_INO(mp, agno, agino))
> +		return 0;
> +
> +	count = MIN(ubleft, (int)(PAGE_SIZE / sizeof(*buffer)));
> +	buffer = kmem_alloc(count * sizeof(*buffer), KM_SLEEP);
> +	do {
> +		struct xfs_aginumbers	ai;
> +
> +		ai.ai_agno = agno;
> +		ai.ai_lastip = &agino;
> +		ai.ai_icount = ubleft;
> +		ai.ai_ubuffer = ubuffer;
> +		ai.ai_ocount = 0;
> +		error = xfs_perag_inumbers(mp, &ai, buffer, count, formatter);
> +		if (error)
> +			break;
> +
> +		*ubcountp += ai.ai_ocount;
> +		ubleft -= ai.ai_ocount;
> +		ASSERT(ubleft >= 0);
> +		if (!ubleft)
> +			break;
> +
> +		ubuffer = ai.ai_ubuffer;
> +		agino = 0;
> +	} while (++agno < mp->m_sb.sb_agcount);
> +
> +	if (!error)
> +		*lastinop = XFS_AGINO_TO_INO(mp, agno, agino);
> +
>  	kmem_free(buffer);
> -	if (cur)
> -		xfs_btree_del_cursor(cur, (error ? XFS_BTREE_ERROR :
> -					   XFS_BTREE_NOERROR));
> -	if (agbp)
> -		xfs_buf_relse(agbp);
>  	return error;
>  }
> diff --git a/fs/xfs/xfs_itable.h b/fs/xfs/xfs_itable.h
> index 60ce988..f78bbcf 100644
> --- a/fs/xfs/xfs_itable.h
> +++ b/fs/xfs/xfs_itable.h
> @@ -83,17 +83,26 @@ xfs_bulkstat_one(
>  
>  typedef int (*inumbers_fmt_pf)(
>  	void			__user *ubuffer, /* buffer to write to */
> -	const xfs_inogrp_t	*buffer,	/* buffer to read from */
> +	const struct xfs_inogrp	*buffer,	/* buffer to read from */
>  	long			count,		/* # of elements to read */
>  	long			*written);	/* # of bytes written */
>  
>  int
>  xfs_inumbers_fmt(
>  	void			__user *ubuffer, /* buffer to write to */
> -	const xfs_inogrp_t	*buffer,	/* buffer to read from */
> +	const struct xfs_inogrp	*buffer,	/* buffer to read from */
>  	long			count,		/* # of elements to read */
>  	long			*written);	/* # of bytes written */
>  
> +/* This structure is used for xfs_inumbers per allocation group */
> +struct xfs_aginumbers {
> +	xfs_agnumber_t		ai_agno;/* AG number */
> +	xfs_agino_t		*ai_lastip;/* last AG inode number */
> +	char			__user *ai_ubuffer;/* user buffer to write to */
> +	__uint32_t		ai_icount;/* # of elements to read */
> +	__uint32_t		ai_ocount;/* # of elements written */
> +};
> +
>  int					/* error status */
>  xfs_inumbers(
>  	xfs_mount_t		*mp,	/* mount point for filesystem */
> 

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