[PATCH 3/6] Replace dquot flush semaphore with a completion

Dave Chinner
2008-06-26T04:42:37Z

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.

Signed-off-by: Dave Chinner <david@fromorbit.com>
---
fs/xfs/quota/xfs_dquot.c | 18 +++++-------------
fs/xfs/quota/xfs_dquot.h | 23 +++++++++++++----------
fs/xfs/quota/xfs_dquot_item.c | 6 +++---
3 files changed, 21 insertions(+), 26 deletions(-)

diff --git a/fs/xfs/quota/xfs_dquot.c b/fs/xfs/quota/xfs_dquot.c
index fc9f3fb..c3e3080 100644
--- a/fs/xfs/quota/xfs_dquot.c
+++ b/fs/xfs/quota/xfs_dquot.c
@@ -101,7 +101,7 @@ xfs_qm_dqinit(
if (brandnewdquot) {
dqp->dq_flnext = dqp->dq_flprev = dqp;
mutex_init(&dqp->q_qlock);
- initnsema(&dqp->q_flock, 1, "fdq");
+ init_completion_flush(&dqp->q_flush);
sv_init(&dqp->q_pinwait, SV_DEFAULT, "pdq");

#ifdef XFS_DQUOT_TRACE
@@ -150,7 +150,6 @@ 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 +1210,7 @@ xfs_qm_dqflush(
int error;

ASSERT(XFS_DQ_IS_LOCKED(dqp));
- ASSERT(XFS_DQ_IS_FLUSH_LOCKED(dqp));
+ ASSERT(completion_flush_inprogress(&dqp->q_flush));
xfs_dqtrace_entry(dqp, "DQFLUSH");

/*
@@ -1353,14 +1352,7 @@ 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);
+ return completion_flush_start_nowait(&dqp->q_flush);
}

@@ -1368,14 +1360,14 @@ 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
diff --git a/fs/xfs/quota/xfs_dquot.h b/fs/xfs/quota/xfs_dquot.h
index f7393bb..c127a45 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 +113,20 @@ 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)
+{
+ completion_flush_start(&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)
diff --git a/fs/xfs/quota/xfs_dquot_item.c b/fs/xfs/quota/xfs_dquot_item.c
index 08d2fc8..a91efa8 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_flush_inprogress(&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_flush_inprogress(&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_flush_inprogress(&dqp->q_flush));
qip->qli_pushbuf_flag = 0;
xfs_dqunlock(dqp);

--
1.5.5.4