[PATCH 10/18] xfs: simplify xfs_map_blocks by using xfs_iext_lookup_extent directly

Christoph Hellwig
2018-05-30T10:01:01Z

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

Note that we now always pass a 0 length to the trace points as we ask
for an unspecified len.

Signed-off-by: Christoph Hellwig <hch@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 587493e9c8a1..cef2bc3cf98b 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;

if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
@@ -429,24 +428,16 @@ xfs_map_blocks(
goto allocate_blocks;
}

- 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 */
--
2.17.0