1 files changed, 328 insertions, 79 deletions

diff --git a/fs/xfs/xfs_alloc.c b/fs/xfs/xfs_alloc.c
index 37c4952c2f5..ff54ef42834 100644
--- a/fs/xfs/xfs_alloc.c
+++ b/fs/xfs/xfs_alloc.c
@@ -41,19 +41,13 @@
 #define XFSA_FIXUP_BNO_OK       1
 #define XFSA_FIXUP_CNT_OK       2
 
-/*
- * Prototypes for per-ag allocation routines
- */
-
 STATIC int xfs_alloc_ag_vextent_exact(xfs_alloc_arg_t *);
 STATIC int xfs_alloc_ag_vextent_near(xfs_alloc_arg_t *);
 STATIC int xfs_alloc_ag_vextent_size(xfs_alloc_arg_t *);
 STATIC int xfs_alloc_ag_vextent_small(xfs_alloc_arg_t *,
-        xfs_btree_cur_t *, xfs_agblock_t *, xfs_extlen_t *, int *);
-
-/*
- * Internal functions.
- */
+                xfs_btree_cur_t *, xfs_agblock_t *, xfs_extlen_t *, int *);
+STATIC void xfs_alloc_busy_trim(struct xfs_alloc_arg *,
+                xfs_agblock_t, xfs_extlen_t, xfs_agblock_t *, xfs_extlen_t *);
 
 /*
  * Lookup the record equal to [bno, len] in the btree given by cur.
@@ -154,19 +148,21 @@ xfs_alloc_compute_aligned(
         xfs_extlen_t    *reslen)        /* result length */
 {
         xfs_agblock_t   bno;
-        xfs_extlen_t    diff;
         xfs_extlen_t    len;
 
-        if (args->alignment > 1 && foundlen >= args->minlen) {
-                bno = roundup(foundbno, args->alignment);
-                diff = bno - foundbno;
-                len = diff >= foundlen ? 0 : foundlen - diff;
+        /* Trim busy sections out of found extent */
+        xfs_alloc_busy_trim(args, foundbno, foundlen, &bno, &len);
+
+        if (args->alignment > 1 && len >= args->minlen) {
+                xfs_agblock_t   aligned_bno = roundup(bno, args->alignment);
+                xfs_extlen_t    diff = aligned_bno - bno;
+
+                *resbno = aligned_bno;
+                *reslen = diff >= len ? 0 : len - diff;
         } else {
-                bno = foundbno;
-                len = foundlen;
+                *resbno = bno;
+                *reslen = len;
         }
-        *resbno = bno;
-        *reslen = len;
 }
 
 /*
@@ -541,16 +537,8 @@ xfs_alloc_ag_vextent(
                 if (error)
                         return error;
 
-                /*
-                 * Search the busylist for these blocks and mark the
-                 * transaction as synchronous if blocks are found. This
-                 * avoids the need to block due to a synchronous log
-                 * force to ensure correct ordering as the synchronous
-                 * transaction will guarantee that for us.
-                 */
-                if (xfs_alloc_busy_search(args->mp, args->agno,
-                                        args->agbno, args->len))
-                        xfs_trans_set_sync(args->tp);
+                ASSERT(!xfs_alloc_busy_search(args->mp, args->agno,
+                                              args->agbno, args->len));
         }
 
         if (!args->isfl) {
@@ -577,14 +565,14 @@ xfs_alloc_ag_vextent_exact(
 {
         xfs_btree_cur_t *bno_cur;/* by block-number btree cursor */
         xfs_btree_cur_t *cnt_cur;/* by count btree cursor */
-        xfs_agblock_t   end;    /* end of allocated extent */
         int             error;
         xfs_agblock_t   fbno;   /* start block of found extent */
-        xfs_agblock_t   fend;   /* end block of found extent */
         xfs_extlen_t    flen;   /* length of found extent */
+        xfs_agblock_t   tbno;   /* start block of trimmed extent */
+        xfs_extlen_t    tlen;   /* length of trimmed extent */
+        xfs_agblock_t   tend;   /* end block of trimmed extent */
+        xfs_agblock_t   end;    /* end of allocated extent */
         int             i;      /* success/failure of operation */
-        xfs_agblock_t   maxend; /* end of maximal extent */
-        xfs_agblock_t   minend; /* end of minimal extent */
         xfs_extlen_t    rlen;   /* length of returned extent */
 
         ASSERT(args->alignment == 1);
@@ -614,14 +602,22 @@ xfs_alloc_ag_vextent_exact(
                 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.
+         * Check for overlapping busy extents.
          */
-        if (fend < minend)
+        xfs_alloc_busy_trim(args, fbno, flen, &tbno, &tlen);
+
+        /*
+         * Give up if the start of the extent is busy, or the freespace isn't
+         * long enough for the minimum request.
+         */
+        if (tbno > args->agbno)
+                goto not_found;
+        if (tlen < args->minlen)
+                goto not_found;
+        tend = tbno + tlen;
+        if (tend < args->agbno + args->minlen)
                 goto not_found;
 
         /*
@@ -630,14 +626,14 @@ xfs_alloc_ag_vextent_exact(
          *
          * Fix the length according to mod and prod if given.
          */
-        end = XFS_AGBLOCK_MIN(fend, maxend);
+        end = XFS_AGBLOCK_MIN(tend, args->agbno + args->maxlen);
         args->len = end - args->agbno;
         xfs_alloc_fix_len(args);
         if (!xfs_alloc_fix_minleft(args))
                 goto not_found;
 
         rlen = args->len;
-        ASSERT(args->agbno + rlen <= fend);
+        ASSERT(args->agbno + rlen <= tend);
         end = args->agbno + rlen;
 
         /*
@@ -686,11 +682,11 @@ xfs_alloc_find_best_extent(
         struct xfs_btree_cur    **scur, /* searching cursor */
         xfs_agblock_t           gdiff,  /* difference for search comparison */
         xfs_agblock_t           *sbno,  /* extent found by search */
-        xfs_extlen_t            *slen,
-        xfs_extlen_t            *slena, /* aligned length */
+        xfs_extlen_t            *slen,  /* extent length */
+        xfs_agblock_t           *sbnoa, /* aligned extent found by search */
+        xfs_extlen_t            *slena, /* aligned extent length */
         int                     dir)    /* 0 = search right, 1 = search left */
 {
-        xfs_agblock_t           bno;
         xfs_agblock_t           new;
         xfs_agblock_t           sdiff;
         int                     error;
@@ -708,16 +704,16 @@ xfs_alloc_find_best_extent(
                 if (error)
                         goto error0;
                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
-                xfs_alloc_compute_aligned(args, *sbno, *slen, &bno, slena);
+                xfs_alloc_compute_aligned(args, *sbno, *slen, sbnoa, slena);
 
                 /*
                  * The good extent is closer than this one.
                  */
                 if (!dir) {
-                        if (bno >= args->agbno + gdiff)
+                        if (*sbnoa >= args->agbno + gdiff)
                                 goto out_use_good;
                 } else {
-                        if (bno <= args->agbno - gdiff)
+                        if (*sbnoa <= args->agbno - gdiff)
                                 goto out_use_good;
                 }
 
@@ -729,8 +725,8 @@ xfs_alloc_find_best_extent(
                         xfs_alloc_fix_len(args);
 
                         sdiff = xfs_alloc_compute_diff(args->agbno, args->len,
-                                                       args->alignment, *sbno,
-                                                       *slen, &new);
+                                                       args->alignment, *sbnoa,
+                                                       *slena, &new);
 
                         /*
                          * Choose closer size and invalidate other cursor.
@@ -780,7 +776,7 @@ xfs_alloc_ag_vextent_near(
         xfs_agblock_t   gtbnoa;         /* aligned ... */
         xfs_extlen_t    gtdiff;         /* difference to right side entry */
         xfs_extlen_t    gtlen;          /* length of right side entry */
-        xfs_extlen_t    gtlena = 0;     /* aligned ... */
+        xfs_extlen_t    gtlena;         /* aligned ... */
         xfs_agblock_t   gtnew;          /* useful start bno of right side */
         int             error;          /* error code */
         int             i;              /* result code, temporary */
@@ -789,9 +785,10 @@ xfs_alloc_ag_vextent_near(
         xfs_agblock_t   ltbnoa;         /* aligned ... */
         xfs_extlen_t    ltdiff;         /* difference to left side entry */
         xfs_extlen_t    ltlen;          /* length of left side entry */
-        xfs_extlen_t    ltlena = 0;     /* aligned ... */
+        xfs_extlen_t    ltlena;         /* aligned ... */
         xfs_agblock_t   ltnew;          /* useful start bno of left side */
         xfs_extlen_t    rlen;           /* length of returned extent */
+        int             forced = 0;
 #if defined(DEBUG) && defined(__KERNEL__)
         /*
          * Randomly don't execute the first algorithm.
@@ -800,13 +797,20 @@ xfs_alloc_ag_vextent_near(
 
         dofirst = random32() & 1;
 #endif
+
+restart:
+        bno_cur_lt = NULL;
+        bno_cur_gt = NULL;
+        ltlen = 0;
+        gtlena = 0;
+        ltlena = 0;
+
         /*
          * Get a cursor for the by-size btree.
          */
         cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
                 args->agno, XFS_BTNUM_CNT);
-        ltlen = 0;
-        bno_cur_lt = bno_cur_gt = NULL;
+
         /*
          * See if there are any free extents as big as maxlen.
          */
@@ -822,11 +826,13 @@ xfs_alloc_ag_vextent_near(
                         goto error0;
                 if (i == 0 || ltlen == 0) {
                         xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
+                        trace_xfs_alloc_near_noentry(args);
                         return 0;
                 }
                 ASSERT(i == 1);
         }
         args->wasfromfl = 0;
+
         /*
          * First algorithm.
          * If the requested extent is large wrt the freespaces available
@@ -890,7 +896,7 @@ xfs_alloc_ag_vextent_near(
                         if (args->len < blen)
                                 continue;
                         ltdiff = xfs_alloc_compute_diff(args->agbno, args->len,
-                                args->alignment, ltbno, ltlen, &ltnew);
+                                args->alignment, ltbnoa, ltlena, &ltnew);
                         if (ltnew != NULLAGBLOCK &&
                             (args->len > blen || ltdiff < bdiff)) {
                                 bdiff = ltdiff;
@@ -1042,11 +1048,12 @@ xfs_alloc_ag_vextent_near(
                         args->len = XFS_EXTLEN_MIN(ltlena, args->maxlen);
                         xfs_alloc_fix_len(args);
                         ltdiff = xfs_alloc_compute_diff(args->agbno, args->len,
-                                args->alignment, ltbno, ltlen, &ltnew);
+                                args->alignment, ltbnoa, ltlena, &ltnew);
 
                         error = xfs_alloc_find_best_extent(args,
                                                 &bno_cur_lt, &bno_cur_gt,
-                                                ltdiff, &gtbno, &gtlen, &gtlena,
+                                                ltdiff, &gtbno, &gtlen,
+                                                &gtbnoa, &gtlena,
                                                 0 /* search right */);
                 } else {
                         ASSERT(gtlena >= args->minlen);
@@ -1057,11 +1064,12 @@ xfs_alloc_ag_vextent_near(
                         args->len = XFS_EXTLEN_MIN(gtlena, args->maxlen);
                         xfs_alloc_fix_len(args);
                         gtdiff = xfs_alloc_compute_diff(args->agbno, args->len,
-                                args->alignment, gtbno, gtlen, &gtnew);
+                                args->alignment, gtbnoa, gtlena, &gtnew);
 
                         error = xfs_alloc_find_best_extent(args,
                                                 &bno_cur_gt, &bno_cur_lt,
-                                                gtdiff, &ltbno, &ltlen, &ltlena,
+                                                gtdiff, &ltbno, &ltlen,
+                                                &ltbnoa, &ltlena,
                                                 1 /* search left */);
                 }
 
@@ -1073,6 +1081,12 @@ xfs_alloc_ag_vextent_near(
          * If we couldn't get anything, give up.
          */
         if (bno_cur_lt == NULL && bno_cur_gt == NULL) {
+                if (!forced++) {
+                        trace_xfs_alloc_near_busy(args);
+                        xfs_log_force(args->mp, XFS_LOG_SYNC);
+                        goto restart;
+                }
+
                 trace_xfs_alloc_size_neither(args);
                 args->agbno = NULLAGBLOCK;
                 return 0;
@@ -1107,12 +1121,13 @@ xfs_alloc_ag_vextent_near(
                 return 0;
         }
         rlen = args->len;
-        (void)xfs_alloc_compute_diff(args->agbno, rlen, args->alignment, ltbno,
-                ltlen, &ltnew);
+        (void)xfs_alloc_compute_diff(args->agbno, rlen, args->alignment,
+                                     ltbnoa, ltlena, &ltnew);
         ASSERT(ltnew >= ltbno);
-        ASSERT(ltnew + rlen <= ltbno + ltlen);
+        ASSERT(ltnew + rlen <= ltbnoa + ltlena);
         ASSERT(ltnew + rlen <= be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_length));
         args->agbno = ltnew;
+
         if ((error = xfs_alloc_fixup_trees(cnt_cur, bno_cur_lt, ltbno, ltlen,
                         ltnew, rlen, XFSA_FIXUP_BNO_OK)))
                 goto error0;
@@ -1155,26 +1170,35 @@ xfs_alloc_ag_vextent_size(
         int             i;              /* temp status variable */
         xfs_agblock_t   rbno;           /* returned block number */
         xfs_extlen_t    rlen;           /* length of returned extent */
+        int             forced = 0;
 
+restart:
         /*
          * Allocate and initialize a cursor for the by-size btree.
          */
         cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
                 args->agno, XFS_BTNUM_CNT);
         bno_cur = NULL;
+
         /*
          * Look for an entry >= maxlen+alignment-1 blocks.
          */
         if ((error = xfs_alloc_lookup_ge(cnt_cur, 0,
                         args->maxlen + args->alignment - 1, &i)))
                 goto error0;
+
         /*
-         * If none, then pick up the last entry in the tree unless the
-         * tree is empty.
+         * If none or we have busy extents that we cannot allocate from, then
+         * we have to settle for a smaller extent. In the case that there are
+         * no large extents, this will return the last entry in the tree unless
+         * the tree is empty. In the case that there are only busy large
+         * extents, this will return the largest small extent unless there
+         * are no smaller extents available.
          */
-        if (!i) {
-                if ((error = xfs_alloc_ag_vextent_small(args, cnt_cur, &fbno,
-                                &flen, &i)))
+        if (!i || forced > 1) {
+                error = xfs_alloc_ag_vextent_small(args, cnt_cur,
+                                                   &fbno, &flen, &i);
+                if (error)
                         goto error0;
                 if (i == 0 || flen == 0) {
                         xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
@@ -1182,22 +1206,56 @@ xfs_alloc_ag_vextent_size(
                         return 0;
                 }
                 ASSERT(i == 1);
+                xfs_alloc_compute_aligned(args, fbno, flen, &rbno, &rlen);
+        } else {
+                /*
+                 * Search for a non-busy extent that is large enough.
+                 * If we are at low space, don't check, or if we fall of
+                 * the end of the btree, turn off the busy check and
+                 * restart.
+                 */
+                for (;;) {
+                        error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, &i);
+                        if (error)
+                                goto error0;
+                        XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
+
+                        xfs_alloc_compute_aligned(args, fbno, flen,
+                                                  &rbno, &rlen);
+
+                        if (rlen >= args->maxlen)
+                                break;
+
+                        error = xfs_btree_increment(cnt_cur, 0, &i);
+                        if (error)
+                                goto error0;
+                        if (i == 0) {
+                                /*
+                                 * Our only valid extents must have been busy.
+                                 * Make it unbusy by forcing the log out and
+                                 * retrying. If we've been here before, forcing
+                                 * the log isn't making the extents available,
+                                 * which means they have probably been freed in
+                                 * this transaction.  In that case, we have to
+                                 * give up on them and we'll attempt a minlen
+                                 * allocation the next time around.
+                                 */
+                                xfs_btree_del_cursor(cnt_cur,
+                                                     XFS_BTREE_NOERROR);
+                                trace_xfs_alloc_size_busy(args);
+                                if (!forced++)
+                                        xfs_log_force(args->mp, XFS_LOG_SYNC);
+                                goto restart;
+                        }
+                }
         }
-        /*
-         * There's a freespace as big as maxlen+alignment-1, get it.
-         */
-        else {
-                if ((error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, &i)))
-                        goto error0;
-                XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
-        }
+
         /*
          * In the first case above, we got the last entry in the
          * by-size btree.  Now we check to see if the space hits maxlen
          * once aligned; if not, we search left for something better.
          * This can't happen in the second case above.
          */
-        xfs_alloc_compute_aligned(args, fbno, flen, &rbno, &rlen);
         rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
         XFS_WANT_CORRUPTED_GOTO(rlen == 0 ||
                         (rlen <= flen && rbno + rlen <= fbno + flen), error0);
@@ -1251,13 +1309,19 @@ xfs_alloc_ag_vextent_size(
          * Fix up the length.
          */
         args->len = rlen;
-        xfs_alloc_fix_len(args);
-        if (rlen < args->minlen || !xfs_alloc_fix_minleft(args)) {
-                xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
-                trace_xfs_alloc_size_nominleft(args);
-                args->agbno = NULLAGBLOCK;
-                return 0;
+        if (rlen < args->minlen) {
+                if (!forced++) {
+                        xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
+                        trace_xfs_alloc_size_busy(args);
+                        xfs_log_force(args->mp, XFS_LOG_SYNC);
+                        goto restart;
+                }
+                goto out_nominleft;
         }
+        xfs_alloc_fix_len(args);
+
+        if (!xfs_alloc_fix_minleft(args))
+                goto out_nominleft;
         rlen = args->len;
         XFS_WANT_CORRUPTED_GOTO(rlen <= flen, error0);
         /*
@@ -1287,6 +1351,12 @@ error0:
         if (bno_cur)
                 xfs_btree_del_cursor(bno_cur, XFS_BTREE_ERROR);
         return error;
+
+out_nominleft:
+        xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
+        trace_xfs_alloc_size_nominleft(args);
+        args->agbno = NULLAGBLOCK;
+        return 0;
 }
 
 /*
@@ -2650,6 +2720,185 @@ xfs_alloc_busy_search(
         return match;
 }
 
+/*
+ * For a given extent [fbno, flen], search the busy extent list to find a
+ * subset of the extent that is not busy.  If *rlen is smaller than
+ * args->minlen no suitable extent could be found, and the higher level
+ * code needs to force out the log and retry the allocation.
+ */
+STATIC void
+xfs_alloc_busy_trim(
+        struct xfs_alloc_arg    *args,
+        xfs_agblock_t           bno,
+        xfs_extlen_t            len,
+        xfs_agblock_t           *rbno,
+        xfs_extlen_t            *rlen)
+{
+        xfs_agblock_t           fbno = bno;
+        xfs_extlen_t            flen = len;
+        struct rb_node          *rbp;
+
+        ASSERT(flen > 0);
+
+        spin_lock(&args->pag->pagb_lock);
+        rbp = args->pag->pagb_tree.rb_node;
+        while (rbp && flen >= args->minlen) {
+                struct xfs_busy_extent *busyp =
+                        rb_entry(rbp, struct xfs_busy_extent, rb_node);
+                xfs_agblock_t   fend = fbno + flen;
+                xfs_agblock_t   bbno = busyp->bno;
+                xfs_agblock_t   bend = bbno + busyp->length;
+
+                if (fend <= bbno) {
+                        rbp = rbp->rb_left;
+                        continue;
+                } else if (fbno >= bend) {
+                        rbp = rbp->rb_right;
+                        continue;
+                }
+
+                if (bbno <= fbno) {
+                        /* start overlap */
+
+                        /*
+                         * Case 1:
+                         *    bbno           bend
+                         *    +BBBBBBBBBBBBBBBBB+
+                         *        +---------+
+                         *        fbno   fend
+                         *
+                         * Case 2:
+                         *    bbno           bend
+                         *    +BBBBBBBBBBBBBBBBB+
+                         *    +-------------+
+                         *    fbno       fend
+                         *
+                         * Case 3:
+                         *    bbno           bend
+                         *    +BBBBBBBBBBBBBBBBB+
+                         *        +-------------+
+                         *        fbno       fend
+                         *
+                         * Case 4:
+                         *    bbno           bend
+                         *    +BBBBBBBBBBBBBBBBB+
+                         *    +-----------------+
+                         *    fbno           fend
+                         *
+                         * No unbusy region in extent, return failure.
+                         */
+                        if (fend <= bend)
+                                goto fail;
+
+                        /*
+                         * Case 5:
+                         *    bbno           bend
+                         *    +BBBBBBBBBBBBBBBBB+
+                         *        +----------------------+
+                         *        fbno                fend
+                         *
+                         * Case 6:
+                         *    bbno           bend
+                         *    +BBBBBBBBBBBBBBBBB+
+                         *    +--------------------------+
+                         *    fbno                    fend
+                         *
+                         * Needs to be trimmed to:
+                         *                       +-------+
+                         *                       fbno fend
+                         */
+                        fbno = bend;
+                } else if (bend >= fend) {
+                        /* end overlap */
+
+                        /*
+                         * Case 7:
+                         *             bbno           bend
+                         *             +BBBBBBBBBBBBBBBBB+
+                         *    +------------------+
+                         *    fbno            fend
+                         *
+                         * Case 8:
+                         *             bbno           bend
+                         *             +BBBBBBBBBBBBBBBBB+
+                         *    +--------------------------+
+                         *    fbno                    fend
+                         *
+                         * Needs to be trimmed to:
+                         *    +-------+
+                         *    fbno fend
+                         */
+                        fend = bbno;
+                } else {
+                        /* middle overlap */
+
+                        /*
+                         * Case 9:
+                         *             bbno           bend
+                         *             +BBBBBBBBBBBBBBBBB+
+                         *    +-----------------------------------+
+                         *    fbno                             fend
+                         *
+                         * Can be trimmed to:
+                         *    +-------+        OR         +-------+
+                         *    fbno fend                   fbno fend
+                         *
+                         * Backward allocation leads to significant
+                         * fragmentation of directories, which degrades
+                         * directory performance, therefore we always want to
+                         * choose the option that produces forward allocation
+                         * patterns.
+                         * Preferring the lower bno extent will make the next
+                         * request use "fend" as the start of the next
+                         * allocation;  if the segment is no longer busy at
+                         * that point, we'll get a contiguous allocation, but
+                         * even if it is still busy, we will get a forward
+                         * allocation.
+                         * We try to avoid choosing the segment at "bend",
+                         * because that can lead to the next allocation
+                         * taking the segment at "fbno", which would be a
+                         * backward allocation.  We only use the segment at
+                         * "fbno" if it is much larger than the current
+                         * requested size, because in that case there's a
+                         * good chance subsequent allocations will be
+                         * contiguous.
+                         */
+                        if (bbno - fbno >= args->maxlen) {
+                                /* left candidate fits perfect */
+                                fend = bbno;
+                        } else if (fend - bend >= args->maxlen * 4) {
+                                /* right candidate has enough free space */
+                                fbno = bend;
+                        } else if (bbno - fbno >= args->minlen) {
+                                /* left candidate fits minimum requirement */
+                                fend = bbno;
+                        } else {
+                                goto fail;
+                        }
+                }
+
+                flen = fend - fbno;
+        }
+        spin_unlock(&args->pag->pagb_lock);
+
+        if (fbno != bno || flen != len) {
+                trace_xfs_alloc_busy_trim(args->mp, args->agno, bno, len,
+                                          fbno, flen);
+        }
+        *rbno = fbno;
+        *rlen = flen;
+        return;
+fail:
+        /*
+         * Return a zero extent length as failure indications.  All callers
+         * re-check if the trimmed extent satisfies the minlen requirement.
+         */
+        spin_unlock(&args->pag->pagb_lock);
+        trace_xfs_alloc_busy_trim(args->mp, args->agno, bno, len, fbno, 0);
+        *rbno = fbno;
+        *rlen = 0;
+}
+
 void
 xfs_alloc_busy_clear(
         struct xfs_mount        *mp,