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Commit 29b3e94a authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Darrick J. Wong
Browse files

xfs: rewrite xfs_bmap_first_unused to make better use of xfs_iext_get_extent 



Look at the return value of xfs_iext_get_extent instead of figuring out
the extent count first and looping up to it.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent 5936dc54

fs/xfs/libxfs/xfs_bmap.c

+26 −30
Original line number Diff line number Diff line
@@ -1285,57 +1285,53 @@ xfs_bmap_read_extents( 
}



/*

 * Returns the file-relative block number of the first unused block(s)

 * in the file with at least "len" logically contiguous blocks free.

 * This is the lowest-address hole if the file has holes, else the first block

 * past the end of file.

 * Return 0 if the file is currently local (in-inode).

 * Returns the relative block number of the first unused block(s) in the given

 * fork with at least "len" logically contiguous blocks free.  This is the

 * lowest-address hole if the fork has holes, else the first block past the end

 * of fork.  Return 0 if the fork is currently local (in-inode).

 */

int						/* error */

xfs_bmap_first_unused(

	xfs_trans_t	*tp,			/* transaction pointer */

	xfs_inode_t	*ip,			/* incore inode */

	struct xfs_trans	*tp,		/* transaction pointer */

	struct xfs_inode	*ip,		/* incore inode */

	xfs_extlen_t		len,		/* size of hole to find */

	xfs_fileoff_t		*first_unused,	/* unused block */

	int			whichfork)	/* data or attr fork */

{

	int		error;			/* error return value */

	int		idx;			/* extent record index */

	xfs_ifork_t	*ifp;			/* inode fork pointer */

	xfs_fileoff_t	lastaddr;		/* last block number seen */

	xfs_fileoff_t	lowest;			/* lowest useful block */

	xfs_fileoff_t	max;			/* starting useful block */

	xfs_extnum_t	nextents;		/* number of extent entries */

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

	struct xfs_bmbt_irec	got;

	xfs_extnum_t		idx = 0;

	xfs_fileoff_t		lastaddr = 0;

	xfs_fileoff_t		lowest, max;

	int			error;



	ASSERT(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);



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

		*first_unused = 0;

		return 0;

	}

	ifp = XFS_IFORK_PTR(ip, whichfork);

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

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

		return error;

	lowest = *first_unused;

	nextents = xfs_iext_count(ifp);

	for (idx = 0, lastaddr = 0, max = lowest; idx < nextents; idx++) {

		struct xfs_bmbt_irec got;



		xfs_iext_get_extent(ifp, idx, &got);

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

		error = xfs_iread_extents(tp, ip, whichfork);

		if (error)

			return error;

	}



	lowest = max = *first_unused;

	while (xfs_iext_get_extent(ifp, idx++, &got)) {

		/*

		 * See if the hole before this extent will work.

		 */

		if (got.br_startoff >= lowest + len &&

		    got.br_startoff - max >= len) {

			*first_unused = max;

			return 0;

		}

		    got.br_startoff - max >= len)

			break;

		lastaddr = got.br_startoff + got.br_blockcount;

		max = XFS_FILEOFF_MAX(lastaddr, lowest);

	}



	*first_unused = max;

	return 0;

}