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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: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-02-14 17:48:20 -05:00
parent 8f82ecae53
commit 7cd916f6ea
1 changed files with 15 additions and 8 deletions
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23
fs/qnx4/inode.c
View File

@ -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;