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Date: Fri, 11 Jul 2008 11:13:49 +1000
From: Dave Chinner <david@...morbit.com>
To: xfs@....sgi.com
Cc: linux-kernel@...r.kernel.org, matthew@....cx,
Dave Chinner <david@...morbit.com>
Subject: [PATCH 5/6] Replace dquot flush semaphore with a completion
Use the new completion flush code to implement the dquot
flush lock. Removes one of the final users of semaphores
in the XFS code base.
Version 2:
o make xfs_qm_dqflock_nowait() a static inline and rename to
match xfs_dqflock/xfs_dqfunlock operations.
o use new completion interface.
Signed-off-by: Dave Chinner <david@...morbit.com>
---
fs/xfs/quota/xfs_dquot.c | 34 ++++++++++++----------------------
fs/xfs/quota/xfs_dquot.h | 29 ++++++++++++++++++-----------
fs/xfs/quota/xfs_dquot_item.c | 8 ++++----
fs/xfs/quota/xfs_qm.c | 8 ++++----
4 files changed, 38 insertions(+), 41 deletions(-)
diff --git a/fs/xfs/quota/xfs_dquot.c b/fs/xfs/quota/xfs_dquot.c
index fc9f3fb..4a2194d 100644
--- a/fs/xfs/quota/xfs_dquot.c
+++ b/fs/xfs/quota/xfs_dquot.c
@@ -101,9 +101,16 @@ xfs_qm_dqinit(
if (brandnewdquot) {
dqp->dq_flnext = dqp->dq_flprev = dqp;
mutex_init(&dqp->q_qlock);
- initnsema(&dqp->q_flock, 1, "fdq");
sv_init(&dqp->q_pinwait, SV_DEFAULT, "pdq");
+ /*
+ * Because we want to use a counting completion, complete
+ * the flush completion once to allow a single access to
+ * the flush completion without blocking.
+ */
+ init_completion(&dqp->q_flush);
+ complete(&dqp->q_flush);
+
#ifdef XFS_DQUOT_TRACE
dqp->q_trace = ktrace_alloc(DQUOT_TRACE_SIZE, KM_SLEEP);
xfs_dqtrace_entry(dqp, "DQINIT");
@@ -150,7 +157,6 @@ xfs_qm_dqdestroy(
ASSERT(! XFS_DQ_IS_ON_FREELIST(dqp));
mutex_destroy(&dqp->q_qlock);
- freesema(&dqp->q_flock);
sv_destroy(&dqp->q_pinwait);
#ifdef XFS_DQUOT_TRACE
@@ -1211,7 +1217,7 @@ xfs_qm_dqflush(
int error;
ASSERT(XFS_DQ_IS_LOCKED(dqp));
- ASSERT(XFS_DQ_IS_FLUSH_LOCKED(dqp));
+ ASSERT(!completion_done(&dqp->q_flush));
xfs_dqtrace_entry(dqp, "DQFLUSH");
/*
@@ -1348,34 +1354,18 @@ xfs_qm_dqflush_done(
xfs_dqfunlock(dqp);
}
-
-int
-xfs_qm_dqflock_nowait(
- xfs_dquot_t *dqp)
-{
- int locked;
-
- locked = cpsema(&((dqp)->q_flock));
-
- /* XXX ifdef these out */
- if (locked)
- (dqp)->dq_flags |= XFS_DQ_FLOCKED;
- return (locked);
-}
-
-
int
xfs_qm_dqlock_nowait(
xfs_dquot_t *dqp)
{
- return (mutex_trylock(&((dqp)->q_qlock)));
+ return mutex_trylock(&dqp->q_qlock);
}
void
xfs_dqlock(
xfs_dquot_t *dqp)
{
- mutex_lock(&(dqp->q_qlock));
+ mutex_lock(&dqp->q_qlock);
}
void
@@ -1468,7 +1458,7 @@ xfs_qm_dqpurge(
* if we're turning off quotas. Basically, we need this flush
* lock, and are willing to block on it.
*/
- if (! xfs_qm_dqflock_nowait(dqp)) {
+ if (!xfs_dqflock_nowait(dqp)) {
/*
* Block on the flush lock after nudging dquot buffer,
* if it is incore.
diff --git a/fs/xfs/quota/xfs_dquot.h b/fs/xfs/quota/xfs_dquot.h
index f7393bb..8958d0f 100644
--- a/fs/xfs/quota/xfs_dquot.h
+++ b/fs/xfs/quota/xfs_dquot.h
@@ -82,7 +82,7 @@ typedef struct xfs_dquot {
xfs_qcnt_t q_res_icount; /* total inos allocd+reserved */
xfs_qcnt_t q_res_rtbcount;/* total realtime blks used+reserved */
mutex_t q_qlock; /* quota lock */
- sema_t q_flock; /* flush lock */
+ struct completion q_flush; /* flush completion queue */
uint q_pincount; /* pin count for this dquot */
sv_t q_pinwait; /* sync var for pinning */
#ifdef XFS_DQUOT_TRACE
@@ -113,17 +113,25 @@ XFS_DQ_IS_LOCKED(xfs_dquot_t *dqp)
/*
- * The following three routines simply manage the q_flock
- * semaphore embedded in the dquot. This semaphore synchronizes
- * processes attempting to flush the in-core dquot back to disk.
+ * Manage the q_flush completion queue embedded in the dquot. This completion
+ * queue synchronizes processes attempting to flush the in-core dquot back to
+ * disk.
*/
-#define xfs_dqflock(dqp) { psema(&((dqp)->q_flock), PINOD | PRECALC);\
- (dqp)->dq_flags |= XFS_DQ_FLOCKED; }
-#define xfs_dqfunlock(dqp) { ASSERT(issemalocked(&((dqp)->q_flock))); \
- vsema(&((dqp)->q_flock)); \
- (dqp)->dq_flags &= ~(XFS_DQ_FLOCKED); }
+static inline void xfs_dqflock(xfs_dquot_t *dqp)
+{
+ wait_for_completion(&dqp->q_flush);
+}
+
+static inline int xfs_dqflock_nowait(xfs_dquot_t *dqp)
+{
+ return try_wait_for_completion(&dqp->q_flush);
+}
+
+static inline void xfs_dqfunlock(xfs_dquot_t *dqp)
+{
+ complete(&dqp->q_flush);
+}
-#define XFS_DQ_IS_FLUSH_LOCKED(dqp) (issemalocked(&((dqp)->q_flock)))
#define XFS_DQ_IS_ON_FREELIST(dqp) ((dqp)->dq_flnext != (dqp))
#define XFS_DQ_IS_DIRTY(dqp) ((dqp)->dq_flags & XFS_DQ_DIRTY)
#define XFS_QM_ISUDQ(dqp) ((dqp)->dq_flags & XFS_DQ_USER)
@@ -167,7 +175,6 @@ extern int xfs_qm_dqflush(xfs_dquot_t *, uint);
extern int xfs_qm_dqpurge(xfs_dquot_t *);
extern void xfs_qm_dqunpin_wait(xfs_dquot_t *);
extern int xfs_qm_dqlock_nowait(xfs_dquot_t *);
-extern int xfs_qm_dqflock_nowait(xfs_dquot_t *);
extern void xfs_qm_dqflock_pushbuf_wait(xfs_dquot_t *dqp);
extern void xfs_qm_adjust_dqtimers(xfs_mount_t *,
xfs_disk_dquot_t *);
diff --git a/fs/xfs/quota/xfs_dquot_item.c b/fs/xfs/quota/xfs_dquot_item.c
index 08d2fc8..f028644 100644
--- a/fs/xfs/quota/xfs_dquot_item.c
+++ b/fs/xfs/quota/xfs_dquot_item.c
@@ -151,7 +151,7 @@ xfs_qm_dquot_logitem_push(
dqp = logitem->qli_dquot;
ASSERT(XFS_DQ_IS_LOCKED(dqp));
- ASSERT(XFS_DQ_IS_FLUSH_LOCKED(dqp));
+ ASSERT(!completion_done(&dqp->q_flush));
/*
* Since we were able to lock the dquot's flush lock and
@@ -245,7 +245,7 @@ xfs_qm_dquot_logitem_pushbuf(
* inode flush completed and the inode was taken off the AIL.
* So, just get out.
*/
- if (!issemalocked(&(dqp->q_flock)) ||
+ if (completion_done(&dqp->q_flush) ||
((qip->qli_item.li_flags & XFS_LI_IN_AIL) == 0)) {
qip->qli_pushbuf_flag = 0;
xfs_dqunlock(dqp);
@@ -258,7 +258,7 @@ xfs_qm_dquot_logitem_pushbuf(
if (bp != NULL) {
if (XFS_BUF_ISDELAYWRITE(bp)) {
dopush = ((qip->qli_item.li_flags & XFS_LI_IN_AIL) &&
- issemalocked(&(dqp->q_flock)));
+ !completion_done(&dqp->q_flush));
qip->qli_pushbuf_flag = 0;
xfs_dqunlock(dqp);
@@ -317,7 +317,7 @@ xfs_qm_dquot_logitem_trylock(
return (XFS_ITEM_LOCKED);
retval = XFS_ITEM_SUCCESS;
- if (! xfs_qm_dqflock_nowait(dqp)) {
+ if (!xfs_dqflock_nowait(dqp)) {
/*
* The dquot is already being flushed. It may have been
* flushed delayed write, however, and we don't want to
diff --git a/fs/xfs/quota/xfs_qm.c b/fs/xfs/quota/xfs_qm.c
index 26370a3..234b6d1 100644
--- a/fs/xfs/quota/xfs_qm.c
+++ b/fs/xfs/quota/xfs_qm.c
@@ -484,7 +484,7 @@ again:
xfs_dqtrace_entry(dqp, "FLUSHALL: DQDIRTY");
/* XXX a sentinel would be better */
recl = XFS_QI_MPLRECLAIMS(mp);
- if (! xfs_qm_dqflock_nowait(dqp)) {
+ if (!xfs_dqflock_nowait(dqp)) {
/*
* If we can't grab the flush lock then check
* to see if the dquot has been flushed delayed
@@ -1062,7 +1062,7 @@ xfs_qm_sync(
/* XXX a sentinel would be better */
recl = XFS_QI_MPLRECLAIMS(mp);
- if (! xfs_qm_dqflock_nowait(dqp)) {
+ if (!xfs_dqflock_nowait(dqp)) {
if (nowait) {
xfs_dqunlock(dqp);
continue;
@@ -2079,7 +2079,7 @@ xfs_qm_shake_freelist(
* Try to grab the flush lock. If this dquot is in the process of
* getting flushed to disk, we don't want to reclaim it.
*/
- if (! xfs_qm_dqflock_nowait(dqp)) {
+ if (!xfs_dqflock_nowait(dqp)) {
xfs_dqunlock(dqp);
dqp = dqp->dq_flnext;
continue;
@@ -2257,7 +2257,7 @@ xfs_qm_dqreclaim_one(void)
* Try to grab the flush lock. If this dquot is in the process of
* getting flushed to disk, we don't want to reclaim it.
*/
- if (! xfs_qm_dqflock_nowait(dqp)) {
+ if (!xfs_dqflock_nowait(dqp)) {
xfs_dqunlock(dqp);
continue;
}
--
1.5.6
--
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