xfs: clean up xfs_alloc_ag_vextent_exact

Use a goto label to consolidate all block not found cases, and add a
tracepoint for them.  Also clean up a few whitespace issues.

Based on an earlier patch from Dave Chinner.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>

2 files changed, 33 insertions, 26 deletions

diff --git a/fs/xfs/linux-2.6/xfs_trace.h b/fs/xfs/linux-2.6/xfs_trace.h
index f56431c916a0..83e8760159ef 100644
--- a/fs/xfs/linux-2.6/xfs_trace.h
+++ b/fs/xfs/linux-2.6/xfs_trace.h
@@ -1422,6 +1422,7 @@ DEFINE_EVENT(xfs_alloc_class, name, \
         TP_PROTO(struct xfs_alloc_arg *args), \
         TP_ARGS(args))
 DEFINE_ALLOC_EVENT(xfs_alloc_exact_done);
+DEFINE_ALLOC_EVENT(xfs_alloc_exact_notfound);
 DEFINE_ALLOC_EVENT(xfs_alloc_exact_error);
 DEFINE_ALLOC_EVENT(xfs_alloc_near_nominleft);
 DEFINE_ALLOC_EVENT(xfs_alloc_near_first);
diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c
index 112abc439ca5..d9133f10d2b1 100644
--- a/fs/xfs/xfs_alloc.c
+++ b/fs/xfs/xfs_alloc.c
@@ -577,61 +577,58 @@ xfs_alloc_ag_vextent_exact(
         xfs_extlen_t    rlen;   /* length of returned extent */
 
         ASSERT(args->alignment == 1);
+
         /*
          * Allocate/initialize a cursor for the by-number freespace btree.
          */
         bno_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
-                args->agno, XFS_BTNUM_BNO);
+                                          args->agno, XFS_BTNUM_BNO);
+
         /*
          * Lookup bno and minlen in the btree (minlen is irrelevant, really).
          * Look for the closest free block <= bno, it must contain bno
          * if any free block does.
          */
-        if ((error = xfs_alloc_lookup_le(bno_cur, args->agbno, args->minlen, &i)))
+        error = xfs_alloc_lookup_le(bno_cur, args->agbno, args->minlen, &i);
+        if (error)
                 goto error0;
-        if (!i) {
-                /*
-                 * Didn't find it, return null.
-                 */
-                xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
-                args->agbno = NULLAGBLOCK;
-                return 0;
-        }
+        if (!i)
+                goto not_found;
+
         /*
          * Grab the freespace record.
          */
-        if ((error = xfs_alloc_get_rec(bno_cur, &fbno, &flen, &i)))
+        error = xfs_alloc_get_rec(bno_cur, &fbno, &flen, &i);
+        if (error)
                 goto error0;
         XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
         ASSERT(fbno <= args->agbno);
         minend = args->agbno + args->minlen;
         maxend = args->agbno + args->maxlen;
         fend = fbno + flen;
+
         /*
          * Give up if the freespace isn't long enough for the minimum request.
          */
-        if (fend < minend) {
-                xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
-                args->agbno = NULLAGBLOCK;
-                return 0;
-        }
+        if (fend < minend)
+                goto not_found;
+
         /*
          * End of extent will be smaller of the freespace end and the
          * maximal requested end.
-         */
-        end = XFS_AGBLOCK_MIN(fend, maxend);
-        /*
+         *
          * Fix the length according to mod and prod if given.
          */
+        end = XFS_AGBLOCK_MIN(fend, maxend);
         args->len = end - args->agbno;
         xfs_alloc_fix_len(args);
-        if (!xfs_alloc_fix_minleft(args)) {
-                xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
-                return 0;
-        }
+        if (!xfs_alloc_fix_minleft(args))
+                goto not_found;
+
         rlen = args->len;
         ASSERT(args->agbno + rlen <= fend);
         end = args->agbno + rlen;
+
         /*
          * We are allocating agbno for rlen [agbno .. end]
          * Allocate/initialize a cursor for the by-size btree.
@@ -640,16 +637,25 @@ xfs_alloc_ag_vextent_exact(
                 args->agno, XFS_BTNUM_CNT);
         ASSERT(args->agbno + args->len <=
                 be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
-        if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen,
-                        args->agbno, args->len, XFSA_FIXUP_BNO_OK))) {
+        error = xfs_alloc_fixup_trees(cnt_cur, bno_cur, fbno, flen, args->agbno,
+                                      args->len, XFSA_FIXUP_BNO_OK);
+        if (error) {
                 xfs_btree_del_cursor(cnt_cur, XFS_BTREE_ERROR);
                 goto error0;
         }
+
         xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
         xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
 
-        trace_xfs_alloc_exact_done(args);
         args->wasfromfl = 0;
+        trace_xfs_alloc_exact_done(args);
+        return 0;
+
+not_found:
+        /* Didn't find it, return null. */
+        xfs_btree_del_cursor(bno_cur, XFS_BTREE_NOERROR);
+        args->agbno = NULLAGBLOCK;
+        trace_xfs_alloc_exact_notfound(args);
         return 0;
 
 error0: