[PATCH 7/7] xfs: factor out code to find the longest free extent in the AG

Christoph Hellwig
2009-02-20T08:53:33Z

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From: Dave Chinner <dgc@sgi.com>

Signed-off-by: Dave Chinner <dgc@sgi.com>

Index: xfs/fs/xfs/xfs_alloc.c
===================================================================
--- xfs.orig/fs/xfs/xfs_alloc.c 2009-02-15 19:40:08.270069722 +0100
+++ xfs/fs/xfs/xfs_alloc.c 2009-02-15 22:50:10.763069641 +0100
@@ -1872,6 +1872,25 @@ xfs_alloc_compute_maxlevels(
}

/*
+ * Find the length of the longest extent in an AG.
+ */
+xfs_extlen_t
+xfs_alloc_min_freelist(
+ struct xfs_mount *mp,
+ struct xfs_perag *pag)
+{
+ xfs_extlen_t need, delta = 0;
+
+ need = XFS_MIN_FREELIST_PAG(pag, mp);
+ if (need > pag->pagf_flcount)
+ delta = need - pag->pagf_flcount;
+
+ if (pag->pagf_longest > delta)
+ return pag->pagf_longest - delta;
+ return pag->pagf_flcount > 0 || pag->pagf_longest > 0;
+}
+
+/*
* Decide whether to use this allocation group for this allocation.
* If so, fix up the btree freelist's size.
*/
@@ -1923,15 +1942,12 @@ xfs_alloc_fix_freelist(
}

if (!(flags & XFS_ALLOC_FLAG_FREEING)) {
- need = XFS_MIN_FREELIST_PAG(pag, mp);
- delta = need > pag->pagf_flcount ? need - pag->pagf_flcount : 0;
/*
* If it looks like there isn't a long enough extent, or enough
* total blocks, reject it.
*/
- longest = (pag->pagf_longest > delta) ?
- (pag->pagf_longest - delta) :
- (pag->pagf_flcount > 0 || pag->pagf_longest > 0);
+ need = XFS_MIN_FREELIST_PAG(pag, mp);
+ longest = xfs_alloc_min_freelist(mp, pag);
if ((args->minlen + args->alignment + args->minalignslop - 1) >
longest ||
((int)(pag->pagf_freeblks + pag->pagf_flcount -
Index: xfs/fs/xfs/xfs_alloc.h
===================================================================
--- xfs.orig/fs/xfs/xfs_alloc.h 2009-02-08 21:51:06.553944398 +0100
+++ xfs/fs/xfs/xfs_alloc.h 2009-02-15 22:47:48.470968077 +0100
@@ -100,6 +100,12 @@ typedef struct xfs_alloc_arg {
#define XFS_ALLOC_USERDATA 1 /* allocation is for user data*/
#define XFS_ALLOC_INITIAL_USER_DATA 2 /* special case start of file */

+/*
+ * Find the length of the longest extent in an AG.
+ */
+xfs_extlen_t
+xfs_alloc_min_freelist(struct xfs_mount *mp,
+ struct xfs_perag *pag);

#ifdef __KERNEL__

Index: xfs/fs/xfs/xfs_bmap.c
===================================================================
--- xfs.orig/fs/xfs/xfs_bmap.c 2009-02-15 19:40:08.724068781 +0100
+++ xfs/fs/xfs/xfs_bmap.c 2009-02-15 22:47:48.478974193 +0100
@@ -2712,9 +2712,6 @@ xfs_bmap_btalloc(
xfs_agnumber_t startag;
xfs_alloc_arg_t args;
xfs_extlen_t blen;
- xfs_extlen_t delta;
- xfs_extlen_t longest;
- xfs_extlen_t need;
xfs_extlen_t nextminlen = 0;
xfs_perag_t *pag;
int nullfb; /* true if ap->firstblock isn't set */
@@ -2796,13 +2793,8 @@ xfs_bmap_btalloc(
* See xfs_alloc_fix_freelist...
*/
if (pag->pagf_init) {
- need = XFS_MIN_FREELIST_PAG(pag, mp);
- delta = need > pag->pagf_flcount ?
- need - pag->pagf_flcount : 0;
- longest = (pag->pagf_longest > delta) ?
- (pag->pagf_longest - delta) :
- (pag->pagf_flcount > 0 ||
- pag->pagf_longest > 0);
+ xfs_extlen_t longest;
+ longest = xfs_alloc_min_freelist(mp, pag);
if (blen < longest)
blen = longest;
} else
Index: xfs/fs/xfs/xfs_filestream.c
===================================================================
--- xfs.orig/fs/xfs/xfs_filestream.c 2009-02-08 21:51:06.575944685 +0100
+++ xfs/fs/xfs/xfs_filestream.c 2009-02-15 22:47:48.479944079 +0100
@@ -140,7 +140,7 @@ _xfs_filestream_pick_ag(
xfs_extlen_t minlen)
{
int err, trylock, nscan;
- xfs_extlen_t delta, longest, need, free, minfree, maxfree = 0;
+ xfs_extlen_t longest, free, minfree, maxfree = 0;
xfs_agnumber_t ag, max_ag = NULLAGNUMBER;
struct xfs_perag *pag;

@@ -186,12 +186,7 @@ _xfs_filestream_pick_ag(
goto next_ag;
}

- need = XFS_MIN_FREELIST_PAG(pag, mp);
- delta = need > pag->pagf_flcount ? need - pag->pagf_flcount : 0;
- longest = (pag->pagf_longest > delta) ?
- (pag->pagf_longest - delta) :
- (pag->pagf_flcount > 0 || pag->pagf_longest > 0);
-
+ longest = xfs_alloc_min_freelist(mp, pag);
if (((minlen && longest >= minlen) ||
(!minlen && pag->pagf_freeblks >= minfree)) &&
(!pag->pagf_metadata || !(flags & XFS_PICK_USERDATA) ||