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xfs: cleanup xfs_bmap_last_before 

Rewrite the function using xfs_iext_lookup_extent and xfs_iext_get_extent,
and massage the flow into something easily understandable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Christoph Hellwig 2016-11-24 11:39:38 +11:00 committed by Dave Chinner
parent 93533c7855
commit 86685f7ba5
1 changed files with 32 additions and 32 deletions
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64
fs/xfs/libxfs/xfs_bmap.c
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@ -1523,44 +1523,44 @@ xfs_bmap_first_unused(
*/
int /* error */
xfs_bmap_last_before(
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, /* transaction pointer */
struct xfs_inode *ip, /* incore inode */
xfs_fileoff_t *last_block, /* last block */
int whichfork) /* data or attr fork */
{
xfs_fileoff_t bno; /* input file offset */
int eof; /* hit end of file */
xfs_bmbt_rec_host_t *ep; /* pointer to last extent */
int error; /* error return value */
xfs_bmbt_irec_t got; /* current extent value */
xfs_ifork_t *ifp; /* inode fork pointer */
xfs_extnum_t lastx; /* last extent used */
xfs_bmbt_irec_t prev; /* previous extent value */
struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, whichfork);
struct xfs_bmbt_irec got;
xfs_extnum_t idx;
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 -EIO;
if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_LOCAL) {
switch (XFS_IFORK_FORMAT(ip, whichfork)) {
case XFS_DINODE_FMT_LOCAL:
*last_block = 0;
return 0;
case XFS_DINODE_FMT_BTREE:
case XFS_DINODE_FMT_EXTENTS:
break;
default:
return -EIO;
}
ifp = XFS_IFORK_PTR(ip, whichfork);
if (!(ifp->if_flags & XFS_IFEXTENTS) &&
(error = xfs_iread_extents(tp, ip, whichfork)))
return error;
bno = *last_block - 1;
ep = xfs_bmap_search_extents(ip, bno, whichfork, &eof, &lastx, &got,
&prev);
if (eof || xfs_bmbt_get_startoff(ep) > bno) {
if (prev.br_startoff == NULLFILEOFF)
*last_block = 0;
else
*last_block = prev.br_startoff + prev.br_blockcount;
if (!(ifp->if_flags & XFS_IFEXTENTS)) {
error = xfs_iread_extents(tp, ip, whichfork);
if (error)
return error;
}
/*
* Otherwise *last_block is already the right answer.
*/
if (xfs_iext_lookup_extent(ip, ifp, *last_block - 1, &idx, &got)) {
if (got.br_startoff <= *last_block - 1)
return 0;
}
if (xfs_iext_get_extent(ifp, idx - 1, &got)) {
*last_block = got.br_startoff + got.br_blockcount;
return 0;
}
*last_block = 0;
return 0;
}