[PATCH 26/34] xfs: simplify xfs_map_blocks by using xfs_iext_lookup_extent directly

[Christoph Hellwig]

xfs_bmapi_read adds zero value in xfs_map_blocks.  Replace it with a
direct call to the low-level extent lookup function.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 fs/xfs/xfs_aops.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 354d26d66c12..b1dee2171194 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -387,7 +387,6 @@ xfs_map_blocks(
        int                     whichfork = XFS_DATA_FORK;
        struct xfs_iext_cursor  icur;
        int                     error = 0;
-       int                     nimaps = 1;
        bool                    cow_valid = false;
 
        if (XFS_FORCED_SHUTDOWN(mp))
@@ -432,24 +431,16 @@ xfs_map_blocks(
                goto done;
        }
 
-       error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
-                               imap, &nimaps, XFS_BMAPI_ENTIRE);
+       if (!xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, imap))
+               imap->br_startoff = end_fsb;    /* fake a hole past EOF */
        xfs_iunlock(ip, XFS_ILOCK_SHARED);
-       if (error)
-               return error;
 
-       if (!nimaps) {
-               /*
-                * Lookup returns no match? Beyond eof? regardless,
-                * return it as a hole so we don't write it
-                */
+       if (imap->br_startoff > offset_fsb) {
+               /* landed in a hole or beyond EOF */
+               imap->br_blockcount = imap->br_startoff - offset_fsb;
                imap->br_startoff = offset_fsb;
-               imap->br_blockcount = end_fsb - offset_fsb;
                imap->br_startblock = HOLESTARTBLOCK;
                *type = XFS_IO_HOLE;
-       } else if (imap->br_startblock == HOLESTARTBLOCK) {
-               /* landed in a hole */
-               *type = XFS_IO_HOLE;
        } else if (isnullstartblock(imap->br_startblock)) {
                /* got a delalloc extent */
                *type = XFS_IO_DELALLOC;
-- 
2.17.0