2 files changed, 18 insertions, 65 deletions

diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index fe925702c955..f2e7eb6e5243 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -362,36 +362,12 @@ xfs_alloc_fix_len(
                 return;
         ASSERT(rlen >= args->minlen && rlen <= args->maxlen);
         ASSERT(rlen % args->prod == args->mod);
+        ASSERT(args->pag->pagf_freeblks + args->pag->pagf_flcount >=
+                rlen + args->minleft);
         args->len = rlen;
 }
 
 /*
- * Fix up length if there is too little space left in the a.g.
- * Return 1 if ok, 0 if too little, should give up.
- */
-STATIC int
-xfs_alloc_fix_minleft(
-        xfs_alloc_arg_t *args)          /* allocation argument structure */
-{
-        xfs_agf_t       *agf;           /* a.g. freelist header */
-        int             diff;           /* free space difference */
-
-        if (args->minleft == 0)
-                return 1;
-        agf = XFS_BUF_TO_AGF(args->agbp);
-        diff = be32_to_cpu(agf->agf_freeblks)
-                - args->len - args->minleft;
-        if (diff >= 0)
-                return 1;
-        args->len += diff;              /* shrink the allocated space */
-        /* casts to (int) catch length underflows */
-        if ((int)args->len >= (int)args->minlen)
-                return 1;
-        args->agbno = NULLAGBLOCK;
-        return 0;
-}
-
-/*
  * Update the two btrees, logically removing from freespace the extent
  * starting at rbno, rlen blocks.  The extent is contained within the
  * actual (current) free extent fbno for flen blocks.
@@ -686,8 +662,6 @@ xfs_alloc_ag_vextent(
         xfs_alloc_arg_t *args)  /* argument structure for allocation */
 {
         int             error=0;
-        xfs_extlen_t    reservation;
-        xfs_extlen_t    oldmax;
 
         ASSERT(args->minlen > 0);
         ASSERT(args->maxlen > 0);
@@ -696,20 +670,6 @@ xfs_alloc_ag_vextent(
         ASSERT(args->alignment > 0);
 
         /*
-         * Clamp maxlen to the amount of free space minus any reservations
-         * that have been made.
-         */
-        oldmax = args->maxlen;
-        reservation = xfs_ag_resv_needed(args->pag, args->resv);
-        if (args->maxlen > args->pag->pagf_freeblks - reservation)
-                args->maxlen = args->pag->pagf_freeblks - reservation;
-        if (args->maxlen == 0) {
-                args->agbno = NULLAGBLOCK;
-                args->maxlen = oldmax;
-                return 0;
-        }
-
-        /*
          * Branch to correct routine based on the type.
          */
         args->wasfromfl = 0;
@@ -728,8 +688,6 @@ xfs_alloc_ag_vextent(
                 /* NOTREACHED */
         }
 
-        args->maxlen = oldmax;
-
         if (error || args->agbno == NULLAGBLOCK)
                 return error;
 
@@ -838,9 +796,6 @@ xfs_alloc_ag_vextent_exact(
         args->len = XFS_AGBLOCK_MIN(tend, args->agbno + args->maxlen)
                                                 - args->agbno;
         xfs_alloc_fix_len(args);
-        if (!xfs_alloc_fix_minleft(args))
-                goto not_found;
-
         ASSERT(args->agbno + args->len <= tend);
 
         /*
@@ -1146,12 +1101,7 @@ restart:
                 XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0);
                 ASSERT(ltbno + ltlen <= be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
                 args->len = blen;
-                if (!xfs_alloc_fix_minleft(args)) {
-                        xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
-                        trace_xfs_alloc_near_nominleft(args);
-                        return 0;
-                }
-                blen = args->len;
+
                 /*
                  * We are allocating starting at bnew for blen blocks.
                  */
@@ -1343,12 +1293,6 @@ restart:
          */
         args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen);
         xfs_alloc_fix_len(args);
-        if (!xfs_alloc_fix_minleft(args)) {
-                trace_xfs_alloc_near_nominleft(args);
-                xfs_btree_del_cursor(bno_cur_lt, XFS_BTREE_NOERROR);
-                xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
-                return 0;
-        }
         rlen = args->len;
         (void)xfs_alloc_compute_diff(args->agbno, rlen, args->alignment,
                                      args->datatype, ltbnoa, ltlena, &ltnew);
@@ -1550,8 +1494,6 @@ restart:
         }
         xfs_alloc_fix_len(args);
 
-        if (!xfs_alloc_fix_minleft(args))
-                goto out_nominleft;
         rlen = args->len;
         XFS_WANT_CORRUPTED_GOTO(args->mp, rlen <= flen, error0);
         /*
@@ -2070,10 +2012,20 @@ xfs_alloc_space_available(
 
         /* do we have enough free space remaining for the allocation? */
         available = (int)(pag->pagf_freeblks + pag->pagf_flcount -
-                          reservation - min_free - args->total);
-        if (available < (int)args->minleft || available <= 0)
+                          reservation - min_free - args->minleft);
+        if (available < (int)args->total)
                 return false;
 
+        /*
+         * Clamp maxlen to the amount of free space available for the actual
+         * extent allocation.
+         */
+        if (available < (int)args->maxlen && !(flags & XFS_ALLOC_FLAG_CHECK)) {
+                args->maxlen = available;
+                ASSERT(args->maxlen > 0);
+                ASSERT(args->maxlen >= args->minlen);
+        }
+
         return true;
 }
 
@@ -2119,7 +2071,8 @@ xfs_alloc_fix_freelist(
         }
 
         need = xfs_alloc_min_freelist(mp, pag);
-        if (!xfs_alloc_space_available(args, need, flags))
+        if (!xfs_alloc_space_available(args, need, flags |
+                        XFS_ALLOC_FLAG_CHECK))
                 goto out_agbp_relse;
 
         /*
diff --git a/fs/xfs/libxfs/xfs_alloc.h b/fs/xfs/libxfs/xfs_alloc.h
index 7c404a6b0ae3..1d0f48a501a3 100644
--- a/fs/xfs/libxfs/xfs_alloc.h
+++ b/fs/xfs/libxfs/xfs_alloc.h
@@ -56,7 +56,7 @@ typedef unsigned int xfs_alloctype_t;
 #define XFS_ALLOC_FLAG_FREEING  0x00000002  /* indicate caller is freeing extents*/
 #define XFS_ALLOC_FLAG_NORMAP   0x00000004  /* don't modify the rmapbt */
 #define XFS_ALLOC_FLAG_NOSHRINK 0x00000008  /* don't shrink the freelist */
-
+#define XFS_ALLOC_FLAG_CHECK    0x00000010  /* test only, don't modify args */
 
 /*
  * Argument structure for xfs_alloc routines.