If we shorten the freelist in xfs_alloc_fix_freelist there is no need
to wait for busy blocks as they will be marked busy again when we call
xfs_free_ag_extent. Avoid this by not marking blocks coming from the
freelist as busy in xfs_free_ag_extent, and not marking transactions
with busy extents as synchronous in xfs_alloc_get_freelist. Unlike
xfs_free_ag_extent which already has the isfl argument,
xfs_alloc_get_freelist needs to be told about the usage of the blocks
it returns. For this we extend the btreeblk flag to a type argument
which specifies in detail what the block is going to be used for.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Index: xfs/fs/xfs/xfs_alloc.c
===================================================================
--- xfs.orig/fs/xfs/xfs_alloc.c 2011-01-17 22:18:20.421254585 +0100
+++ xfs/fs/xfs/xfs_alloc.c 2011-01-17 22:30:54.006256540 +0100
@@ -1395,7 +1395,8 @@ xfs_alloc_ag_vextent_small(
else if (args->minlen == 1 && args->alignment == 1 && !args->isfl &&
(be32_to_cpu(XFS_BUF_TO_AGF(args->agbp)->agf_flcount)
> args->minleft)) {
- error = xfs_alloc_get_freelist(args->tp, args->agbp, &fbno, 0);
+ error = xfs_alloc_get_freelist(args->tp, args->agbp, &fbno,
+ XFS_FREELIST_ALLOC);
if (error)
goto error0;
if (fbno != NULLAGBLOCK) {
@@ -1683,25 +1684,20 @@ xfs_free_ag_extent(
if (error)
goto error0;
- if (!isfl)
+ if (!isfl) {
xfs_trans_mod_sb(tp, XFS_TRANS_SB_FDBLOCKS, (long)len);
+
+ /*
+ * Mark the extent busy unless it comes from the freelist,
+ * in which case it has already been marked busy.
+ */
+ xfs_alloc_busy_insert(tp, agno, bno, len);
+ }
+
XFS_STATS_INC(xs_freex);
XFS_STATS_ADD(xs_freeb, len);
trace_xfs_free_extent(mp, agno, bno, len, isfl, haveleft, haveright);
-
- /*
- * Since blocks move to the free list without the coordination
- * used in xfs_bmap_finish, we can't allow block to be available
- * for reallocation and non-transaction writing (user data)
- * until we know that the transaction that moved it to the free
- * list is permanently on disk. We track the blocks by declaring
- * these blocks as "busy"; the busy list is maintained on a per-ag
- * basis and each transaction records which entries should be removed
- * when the iclog commits to disk. If a busy block is allocated,
- * the iclog is pushed up to the LSN that freed the block.
- */
- xfs_alloc_busy_insert(tp, agno, bno, len);
return 0;
error0:
@@ -1873,11 +1869,14 @@ xfs_alloc_fix_freelist(
while (be32_to_cpu(agf->agf_flcount) > need) {
xfs_buf_t *bp;
- error = xfs_alloc_get_freelist(tp, agbp, &bno, 0);
+ error = xfs_alloc_get_freelist(tp, agbp, &bno,
+ XFS_FREELIST_BALANCE);
if (error)
return error;
- if ((error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1)))
+ error = xfs_free_ag_extent(tp, agbp, args->agno, bno, 1, 1);
+ if (error)
return error;
+
bp = xfs_btree_get_bufs(mp, tp, args->agno, bno, 0);
xfs_trans_binval(tp, bp);
}
@@ -1944,18 +1943,18 @@ xfs_alloc_get_freelist(
xfs_trans_t *tp, /* transaction pointer */
xfs_buf_t *agbp, /* buffer containing the agf structure */
xfs_agblock_t *bnop, /* block address retrieved from freelist */
- int btreeblk) /* destination is a AGF btree */
+ int type) /* where does the allocation go to? */
{
- xfs_agf_t *agf; /* a.g. freespace structure */
+ xfs_mount_t *mp = tp->t_mountp;
+ xfs_agf_t *agf = XFS_BUF_TO_AGF(agbp);
+ xfs_agnumber_t agno = be32_to_cpu(agf->agf_seqno);
xfs_agfl_t *agfl; /* a.g. freelist structure */
xfs_buf_t *agflbp;/* buffer for a.g. freelist structure */
xfs_agblock_t bno; /* block number returned */
int error;
int logflags;
- xfs_mount_t *mp; /* mount structure */
xfs_perag_t *pag; /* per allocation group data */
- agf = XFS_BUF_TO_AGF(agbp);
/*
* Freelist is empty, give up.
*/
@@ -1963,14 +1962,15 @@ xfs_alloc_get_freelist(
*bnop = NULLAGBLOCK;
return 0;
}
+
/*
* Read the array of free blocks.
*/
- mp = tp->t_mountp;
- if ((error = xfs_alloc_read_agfl(mp, tp,
- be32_to_cpu(agf->agf_seqno), &agflbp)))
+ error = xfs_alloc_read_agfl(mp, tp, agno, &agflbp);
+ if (error)
return error;
agfl = XFS_BUF_TO_AGFL(agflbp);
+
/*
* Get the block number and update the data structures.
*/
@@ -1980,14 +1980,14 @@ xfs_alloc_get_freelist(
if (be32_to_cpu(agf->agf_flfirst) == XFS_AGFL_SIZE(mp))
agf->agf_flfirst = 0;
- pag = xfs_perag_get(mp, be32_to_cpu(agf->agf_seqno));
+ pag = xfs_perag_get(mp, agno);
be32_add_cpu(&agf->agf_flcount, -1);
xfs_trans_agflist_delta(tp, -1);
pag->pagf_flcount--;
xfs_perag_put(pag);
logflags = XFS_AGF_FLFIRST | XFS_AGF_FLCOUNT;
- if (btreeblk) {
+ if (type == XFS_FREELIST_BTREE) {
be32_add_cpu(&agf->agf_btreeblks, 1);
pag->pagf_btreeblks++;
logflags |= XFS_AGF_BTREEBLKS;
@@ -2009,8 +2009,11 @@ xfs_alloc_get_freelist(
* that we don't sit and wait with the AGF locked in the transaction
* during the log force.
*/
- if (xfs_alloc_busy_search(mp, be32_to_cpu(agf->agf_seqno), bno, 1))
- xfs_trans_set_sync(tp);
+ if (type != XFS_FREELIST_BALANCE) {
+ if (xfs_alloc_busy_search(mp, agno, bno, 1))
+ xfs_trans_set_sync(tp);
+ }
+
return 0;
}
Index: xfs/fs/xfs/xfs_alloc.h
===================================================================
--- xfs.orig/fs/xfs/xfs_alloc.h 2011-01-17 22:23:05.168004061 +0100
+++ xfs/fs/xfs/xfs_alloc.h 2011-01-17 22:30:06.456005528 +0100
@@ -140,6 +140,13 @@ xfs_alloc_compute_maxlevels(
struct xfs_mount *mp); /* file system mount structure */
/*
+ * Destination of blocks allocated by xfs_alloc_get_freelist.
+ */
+#define XFS_FREELIST_ALLOC 0
+#define XFS_FREELIST_BTREE 1
+#define XFS_FREELIST_BALANCE 2
+
+/*
* Get a block from the freelist.
* Returns with the buffer for the block gotten.
*/
Index: xfs/fs/xfs/xfs_alloc_btree.c
===================================================================
--- xfs.orig/fs/xfs/xfs_alloc_btree.c 2011-01-17 22:23:05.155004271 +0100
+++ xfs/fs/xfs/xfs_alloc_btree.c 2011-01-17 22:24:35.867255145 +0100
@@ -83,7 +83,7 @@ xfs_allocbt_alloc_block(
/* Allocate the new block from the freelist. If we can't, give up. */
error = xfs_alloc_get_freelist(cur->bc_tp, cur->bc_private.a.agbp,
- &bno, 1);
+ &bno, XFS_FREELIST_BTREE);
if (error) {
XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
return error;
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