[PATCH 3/6] XFS: Convert filestreams code to use per-ag get/put routines

Dave Chinner
2009-12-15T06:11:05Z

Signed-off-by: Dave Chinner <david@fromorbit.com>
---
fs/xfs/xfs_filestream.c | 19 ++++++++++++-------
fs/xfs/xfs_filestream.h | 27 ++++++++++++++++++++++++---
2 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c
index a631e14..e61f2aa 100644
--- a/fs/xfs/xfs_filestream.c
+++ b/fs/xfs/xfs_filestream.c
@@ -140,6 +140,7 @@ _xfs_filestream_pick_ag(
int flags,
xfs_extlen_t minlen)
{
+ int streams, max_streams;
int err, trylock, nscan;
xfs_extlen_t longest, free, minfree, maxfree = 0;
xfs_agnumber_t ag, max_ag = NULLAGNUMBER;
@@ -155,15 +156,15 @@ _xfs_filestream_pick_ag(
trylock = XFS_ALLOC_FLAG_TRYLOCK;

for (nscan = 0; 1; nscan++) {
-
- TRACE_AG_SCAN(mp, ag, xfs_filestream_peek_ag(mp, ag));
-
- pag = mp->m_perag + ag;
+ pag = xfs_perag_get(mp, ag);
+ TRACE_AG_SCAN(mp, ag, atomic_read(&pag->pagf_fstrms));

if (!pag->pagf_init) {
err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);
- if (err && !trylock)
+ if (err && !trylock) {
+ xfs_perag_put(pag);
return err;
+ }
}

/* Might fail sometimes during the 1st pass with trylock set. */
@@ -173,6 +174,7 @@ _xfs_filestream_pick_ag(
/* Keep track of the AG with the most free blocks. */
if (pag->pagf_freeblks > maxfree) {
maxfree = pag->pagf_freeblks;
+ max_streams = atomic_read(&pag->pagf_fstrms);
max_ag = ag;
}

@@ -195,6 +197,8 @@ _xfs_filestream_pick_ag(

/* Break out, retaining the reference on the AG. */
free = pag->pagf_freeblks;
+ streams = atomic_read(&pag->pagf_fstrms);
+ xfs_perag_put(pag);
*agp = ag;
break;
}
@@ -202,6 +206,7 @@ _xfs_filestream_pick_ag(
/* Drop the reference on this AG, it's not usable. */
xfs_filestream_put_ag(mp, ag);
next_ag:
+ xfs_perag_put(pag);
/* Move to the next AG, wrapping to AG 0 if necessary. */
if (++ag >= mp->m_sb.sb_agcount)
ag = 0;
@@ -229,6 +234,7 @@ next_ag:
if (max_ag != NULLAGNUMBER) {
xfs_filestream_get_ag(mp, max_ag);
TRACE_AG_PICK1(mp, max_ag, maxfree);
+ streams = max_streams;
free = maxfree;
*agp = max_ag;
break;
@@ -240,8 +246,7 @@ next_ag:
return 0;
}

- TRACE_AG_PICK2(mp, startag, *agp, xfs_filestream_peek_ag(mp, *agp),
- free, nscan, flags);
+ TRACE_AG_PICK2(mp, startag, *agp, streams, free, nscan, flags);

return 0;
}
diff --git a/fs/xfs/xfs_filestream.h b/fs/xfs/xfs_filestream.h
index 4aba67c..58378b2 100644
--- a/fs/xfs/xfs_filestream.h
+++ b/fs/xfs/xfs_filestream.h
@@ -79,12 +79,21 @@ extern ktrace_t *xfs_filestreams_trace_buf;
* the cache that reference per-ag array elements that have since been
* reallocated.
*/
+/*
+ * xfs_filestream_peek_ag is only used in tracing code
+ */
static inline int
xfs_filestream_peek_ag(
xfs_mount_t *mp,
xfs_agnumber_t agno)
{
- return atomic_read(&mp->m_perag[agno].pagf_fstrms);
+ struct xfs_perag *pag;
+ int ret;
+
+ pag = xfs_perag_get(mp, agno);
+ ret = atomic_read(&pag->pagf_fstrms);
+ xfs_perag_put(pag);
+ return ret;
}

static inline int
@@ -92,7 +101,13 @@ xfs_filestream_get_ag(
xfs_mount_t *mp,
xfs_agnumber_t agno)
{
- return atomic_inc_return(&mp->m_perag[agno].pagf_fstrms);
+ struct xfs_perag *pag;
+ int ret;
+
+ pag = xfs_perag_get(mp, agno);
+ ret = atomic_inc_return(&pag->pagf_fstrms);
+ xfs_perag_put(pag);
+ return ret;
}

static inline int
@@ -100,7 +115,13 @@ xfs_filestream_put_ag(
xfs_mount_t *mp,
xfs_agnumber_t agno)
{
- return atomic_dec_return(&mp->m_perag[agno].pagf_fstrms);
+ struct xfs_perag *pag;
+ int ret;
+
+ pag = xfs_perag_get(mp, agno);
+ ret = atomic_dec_return(&pag->pagf_fstrms);
+ xfs_perag_put(pag);
+ return ret;
}

/* allocation selection flags */
--
1.6.5