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Commit 7cd916f6 authored by Al Viro's avatar Al Viro
Browse files

qnx4: new helper - try_extent() 



checking if an extent is the one we are looking for is done twice
in qnx4_block_map(); gather that code into a helper function.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 8f82ecae

fs/qnx4/inode.c

+15 −8
Original line number Diff line number Diff line
@@ -66,23 +66,31 @@ static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_h 
	return 0;

}



static inline u32 try_extent(qnx4_xtnt_t *extent, u32 *offset)

{

	u32 size = le32_to_cpu(extent->xtnt_size);

	if (*offset < size)

		return le32_to_cpu(extent->xtnt_blk) + *offset - 1;

	*offset -= size;

	return 0;

}



unsigned long qnx4_block_map( struct inode *inode, long iblock )

{

	int ix;

	long offset, i_xblk;

	unsigned long block = 0;

	long i_xblk;

	struct buffer_head *bh = NULL;

	struct qnx4_xblk *xblk = NULL;

	struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);

	u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);

	u32 offset = iblock;

	u32 block = try_extent(&qnx4_inode->di_first_xtnt, &offset);



	if ( iblock < le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size) ) {

	if (block) {

		// iblock is in the first extent. This is easy.

		block = le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_blk) + iblock - 1;

	} else {

		// iblock is beyond first extent. We have to follow the extent chain.

		i_xblk = le32_to_cpu(qnx4_inode->di_xblk);

		offset = iblock - le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size);

		ix = 0;

		while ( --nxtnt > 0 ) {

			if ( ix == 0 ) {
@@ -98,12 +106,11 @@ unsigned long qnx4_block_map( struct inode *inode, long iblock ) 
					return -EIO;

				}

			}

			if ( offset < le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size) ) {

			block = try_extent(&xblk->xblk_xtnts[ix], &offset);

			if (block) {

				// got it!

				block = le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_blk) + offset - 1;

				break;

			}

			offset -= le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size);

			if ( ++ix >= xblk->xblk_num_xtnts ) {

				i_xblk = le32_to_cpu(xblk->xblk_next_xblk);

				ix = 0;