Commit 27a3f8f2 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Alex Elder
Browse files

xfs: introduce xfs_bmap_last_extent 



Add a common helper for finding the last extent in a file.

Largely based on a patch from Dave Chinner.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAlex Elder <aelder@sgi.com>
parent c0dc7828

fs/xfs/xfs_bmap.c

+105 −121
Original line number Diff line number Diff line
@@ -203,19 +203,6 @@ xfs_bmap_search_extents( 
	xfs_bmbt_irec_t	*gotp,		/* out: extent entry found */

	xfs_bmbt_irec_t	*prevp);	/* out: previous extent entry found */



/*

 * Check the last inode extent to determine whether this allocation will result

 * in blocks being allocated at the end of the file. When we allocate new data

 * blocks at the end of the file which do not start at the previous data block,

 * we will try to align the new blocks at stripe unit boundaries.

 */

STATIC int				/* error */

xfs_bmap_isaeof(

	xfs_inode_t	*ip,		/* incore inode pointer */

	xfs_fileoff_t   off,		/* file offset in fsblocks */

	int             whichfork,	/* data or attribute fork */

	char		*aeof);		/* return value */



/*

 * Compute the worst-case number of indirect blocks that will be used

 * for ip's delayed extent of length "len".
@@ -3924,42 +3911,122 @@ xfs_bmap_last_before( 
	return 0;

}



STATIC int

xfs_bmap_last_extent(

	struct xfs_trans	*tp,

	struct xfs_inode	*ip,

	int			whichfork,

	struct xfs_bmbt_irec	*rec,

	int			*is_empty)

{

	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);

	int			error;

	int			nextents;



	if (!(ifp->if_flags & XFS_IFEXTENTS)) {

		error = xfs_iread_extents(tp, ip, whichfork);

		if (error)

			return error;

	}



	nextents = ifp->if_bytes / sizeof(xfs_bmbt_rec_t);

	if (nextents == 0) {

		*is_empty = 1;

		return 0;

	}



	xfs_bmbt_get_all(xfs_iext_get_ext(ifp, nextents - 1), rec);

	*is_empty = 0;

	return 0;

}



/*

 * Check the last inode extent to determine whether this allocation will result

 * in blocks being allocated at the end of the file. When we allocate new data

 * blocks at the end of the file which do not start at the previous data block,

 * we will try to align the new blocks at stripe unit boundaries.

 *

 * Returns 0 in *aeof if the file (fork) is empty as any new write will be at,

 * or past the EOF.

 */

STATIC int

xfs_bmap_isaeof(

	struct xfs_inode	*ip,

	xfs_fileoff_t		off,

	int			whichfork,

	char			*aeof)

{

	struct xfs_bmbt_irec	rec;

	int			is_empty;

	int			error;



	*aeof = 0;

	error = xfs_bmap_last_extent(NULL, ip, whichfork, &rec, &is_empty);

	if (error || is_empty)

		return error;



	/*

	 * Check if we are allocation or past the last extent, or at least into

	 * the last delayed allocated extent.

	 */

	*aeof = off >= rec.br_startoff + rec.br_blockcount ||

		(off >= rec.br_startoff && isnullstartblock(rec.br_startblock));

	return 0;

}



/*

 * Check if the endoff is outside the last extent. If so the caller will grow

 * the allocation to a stripe unit boundary.  All offsets are considered outside

 * the end of file for an empty fork, so 1 is returned in *eof in that case.

 */

int

xfs_bmap_eof(

	struct xfs_inode	*ip,

	xfs_fileoff_t		endoff,

	int			whichfork,

	int			*eof)

{

	struct xfs_bmbt_irec	rec;

	int			error;



	error = xfs_bmap_last_extent(NULL, ip, whichfork, &rec, eof);

	if (error || *eof)

		return error;



	*eof = endoff >= rec.br_startoff + rec.br_blockcount;

	return 0;

}



/*

 * Returns the file-relative block number of the first block past eof in

 * the file.  This is not based on i_size, it is based on the extent records.

 * Returns 0 for local files, as they do not have extent records.

 */

int						/* error */

int

xfs_bmap_last_offset(

	xfs_trans_t	*tp,			/* transaction pointer */

	xfs_inode_t	*ip,			/* incore inode */

	xfs_fileoff_t	*last_block,		/* last block */

	int		whichfork)		/* data or attr fork */

	struct xfs_trans	*tp,

	struct xfs_inode	*ip,

	xfs_fileoff_t		*last_block,

	int			whichfork)

{

	xfs_bmbt_rec_host_t *ep;		/* pointer to last extent */

	int		error;			/* error return value */

	xfs_ifork_t	*ifp;			/* inode fork pointer */

	xfs_extnum_t	nextents;		/* number of extent entries */

	struct xfs_bmbt_irec	rec;

	int			is_empty;

	int			error;



	if (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE &&

	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS &&

	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_LOCAL)

	       return XFS_ERROR(EIO);

	if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL) {

	*last_block = 0;



	if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL)

		return 0;

	}

	ifp = XFS_IFORK_PTR(ip, whichfork);

	if (!(ifp->if_flags & XFS_IFEXTENTS) &&

	    (error = xfs_iread_extents(tp, ip, whichfork)))



	if (XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_BTREE &&

	    XFS_IFORK_FORMAT(ip, whichfork) != XFS_DINODE_FMT_EXTENTS)

	       return XFS_ERROR(EIO);



	error = xfs_bmap_last_extent(NULL, ip, whichfork, &rec, &is_empty);

	if (error || is_empty)

		return error;

	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);

	if (!nextents) {

		*last_block = 0;

		return 0;

	}

	ep = xfs_iext_get_ext(ifp, nextents - 1);

	*last_block = xfs_bmbt_get_startoff(ep) + xfs_bmbt_get_blockcount(ep);



	*last_block = rec.br_startoff + rec.br_blockcount;

	return 0;

}
@@ -5687,89 +5754,6 @@ xfs_getbmap( 
	return error;

}



/*

 * Check the last inode extent to determine whether this allocation will result

 * in blocks being allocated at the end of the file. When we allocate new data

 * blocks at the end of the file which do not start at the previous data block,

 * we will try to align the new blocks at stripe unit boundaries.

 */

STATIC int				/* error */

xfs_bmap_isaeof(

	xfs_inode_t	*ip,		/* incore inode pointer */

	xfs_fileoff_t   off,		/* file offset in fsblocks */

	int             whichfork,	/* data or attribute fork */

	char		*aeof)		/* return value */

{

	int		error;		/* error return value */

	xfs_ifork_t	*ifp;		/* inode fork pointer */

	xfs_bmbt_rec_host_t *lastrec;	/* extent record pointer */

	xfs_extnum_t	nextents;	/* number of file extents */

	xfs_bmbt_irec_t	s;		/* expanded extent record */



	ASSERT(whichfork == XFS_DATA_FORK);

	ifp = XFS_IFORK_PTR(ip, whichfork);

	if (!(ifp->if_flags & XFS_IFEXTENTS) &&

	    (error = xfs_iread_extents(NULL, ip, whichfork)))

		return error;

	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);

	if (nextents == 0) {

		*aeof = 1;

		return 0;

	}

	/*

	 * Go to the last extent

	 */

	lastrec = xfs_iext_get_ext(ifp, nextents - 1);

	xfs_bmbt_get_all(lastrec, &s);

	/*

	 * Check we are allocating in the last extent (for delayed allocations)

	 * or past the last extent for non-delayed allocations.

	 */

	*aeof = (off >= s.br_startoff &&

		 off < s.br_startoff + s.br_blockcount &&

		 isnullstartblock(s.br_startblock)) ||

		off >= s.br_startoff + s.br_blockcount;

	return 0;

}



/*

 * Check if the endoff is outside the last extent. If so the caller will grow

 * the allocation to a stripe unit boundary.

 */

int					/* error */

xfs_bmap_eof(

	xfs_inode_t	*ip,		/* incore inode pointer */

	xfs_fileoff_t	endoff,		/* file offset in fsblocks */

	int		whichfork,	/* data or attribute fork */

	int		*eof)		/* result value */

{

	xfs_fsblock_t	blockcount;	/* extent block count */

	int		error;		/* error return value */

	xfs_ifork_t	*ifp;		/* inode fork pointer */

	xfs_bmbt_rec_host_t *lastrec;	/* extent record pointer */

	xfs_extnum_t	nextents;	/* number of file extents */

	xfs_fileoff_t	startoff;	/* extent starting file offset */



	ASSERT(whichfork == XFS_DATA_FORK);

	ifp = XFS_IFORK_PTR(ip, whichfork);

	if (!(ifp->if_flags & XFS_IFEXTENTS) &&

	    (error = xfs_iread_extents(NULL, ip, whichfork)))

		return error;

	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);

	if (nextents == 0) {

		*eof = 1;

		return 0;

	}

	/*

	 * Go to the last extent

	 */

	lastrec = xfs_iext_get_ext(ifp, nextents - 1);

	startoff = xfs_bmbt_get_startoff(lastrec);

	blockcount = xfs_bmbt_get_blockcount(lastrec);

	*eof = endoff >= startoff + blockcount;

	return 0;

}



#ifdef DEBUG

STATIC struct xfs_buf *

xfs_bmap_get_bp(