[PATCH 25/28] xfs: clean up buffer locking helpers

Christoph Hellwig
2011-07-07T11:06:47Z

[-- Attachment #1: xfs-cleanup-buffer-locking --]
[-- Type: text/plain, Size: 11278 bytes --]

Rename xfs_buf_cond_lock and reverse it's return value to fit most other
trylock operations in the Kernel and XFS (with the exception of down_trylock,
after which xfs_buf_cond_lock was modelled), and replace xfs_buf_lock_val
with an xfs_buf_islocked for use in asserts, or and opencoded variant in
tracing. remove the XFS_BUF_* wrappers for all the locking helpers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Index: xfs/fs/xfs/linux-2.6/xfs_buf.c
===================================================================
--- xfs.orig/fs/xfs/linux-2.6/xfs_buf.c 2011-06-29 11:26:14.000000000 +0200
+++ xfs/fs/xfs/linux-2.6/xfs_buf.c 2011-06-29 13:57:15.596795734 +0200
@@ -499,16 +499,14 @@ found:
spin_unlock(&pag->pag_buf_lock);
xfs_perag_put(pag);

- if (xfs_buf_cond_lock(bp)) {
- /* failed, so wait for the lock if requested. */
- if (!(flags & XBF_TRYLOCK)) {
- xfs_buf_lock(bp);
- XFS_STATS_INC(xb_get_locked_waited);
- } else {
+ if (!xfs_buf_trylock(bp)) {
+ if (flags & XBF_TRYLOCK) {
xfs_buf_rele(bp);
XFS_STATS_INC(xb_busy_locked);
return NULL;
}
+ xfs_buf_lock(bp);
+ XFS_STATS_INC(xb_get_locked_waited);
}

/*
@@ -896,8 +894,8 @@ xfs_buf_rele(
* to push on stale inode buffers.
*/
int
-xfs_buf_cond_lock(
- xfs_buf_t *bp)
+xfs_buf_trylock(
+ struct xfs_buf *bp)
{
int locked;

@@ -907,15 +905,8 @@ xfs_buf_cond_lock(
else if (atomic_read(&bp->b_pin_count) && (bp->b_flags & XBF_STALE))
xfs_log_force(bp->b_target->bt_mount, 0);

- trace_xfs_buf_cond_lock(bp, _RET_IP_);
- return locked ? 0 : -EBUSY;
-}
-
-int
-xfs_buf_lock_value(
- xfs_buf_t *bp)
-{
- return bp->b_sema.count;
+ trace_xfs_buf_trylock(bp, _RET_IP_);
+ return locked;
}

/*
@@ -929,7 +920,7 @@ xfs_buf_lock_value(
*/
void
xfs_buf_lock(
- xfs_buf_t *bp)
+ struct xfs_buf *bp)
{
trace_xfs_buf_lock(bp, _RET_IP_);

@@ -950,7 +941,7 @@ xfs_buf_lock(
*/
void
xfs_buf_unlock(
- xfs_buf_t *bp)
+ struct xfs_buf *bp)
{
if ((bp->b_flags & (XBF_DELWRI|_XBF_DELWRI_Q)) == XBF_DELWRI) {
atomic_inc(&bp->b_hold);
@@ -1694,7 +1685,7 @@ xfs_buf_delwri_split(
list_for_each_entry_safe(bp, n, dwq, b_list) {
ASSERT(bp->b_flags & XBF_DELWRI);

- if (!XFS_BUF_ISPINNED(bp) && !xfs_buf_cond_lock(bp)) {
+ if (!XFS_BUF_ISPINNED(bp) && xfs_buf_trylock(bp)) {
if (!force &&
time_before(jiffies, bp->b_queuetime + age)) {
xfs_buf_unlock(bp);
Index: xfs/fs/xfs/linux-2.6/xfs_buf.h
===================================================================
--- xfs.orig/fs/xfs/linux-2.6/xfs_buf.h 2011-06-29 13:50:40.000000000 +0200
+++ xfs/fs/xfs/linux-2.6/xfs_buf.h 2011-06-29 13:54:35.250997736 +0200
@@ -187,10 +187,11 @@ extern void xfs_buf_free(xfs_buf_t *);
extern void xfs_buf_rele(xfs_buf_t *);

/* Locking and Unlocking Buffers */
-extern int xfs_buf_cond_lock(xfs_buf_t *);
-extern int xfs_buf_lock_value(xfs_buf_t *);
+extern int xfs_buf_trylock(xfs_buf_t *);
extern void xfs_buf_lock(xfs_buf_t *);
extern void xfs_buf_unlock(xfs_buf_t *);
+#define xfs_buf_islocked(bp) \
+ ((bp)->b_sema.count <= 0)

/* Buffer Read and Write Routines */
extern int xfs_bwrite(struct xfs_mount *mp, struct xfs_buf *bp);
@@ -308,10 +309,6 @@ xfs_buf_set_ref(

#define XFS_BUF_ISPINNED(bp) atomic_read(&((bp)->b_pin_count))

-#define XFS_BUF_VALUSEMA(bp) xfs_buf_lock_value(bp)
-#define XFS_BUF_CPSEMA(bp) (xfs_buf_cond_lock(bp) == 0)
-#define XFS_BUF_VSEMA(bp) xfs_buf_unlock(bp)
-#define XFS_BUF_PSEMA(bp,x) xfs_buf_lock(bp)
#define XFS_BUF_FINISH_IOWAIT(bp) complete(&bp->b_iowait);

#define XFS_BUF_SET_TARGET(bp, target) ((bp)->b_target = (target))
Index: xfs/fs/xfs/linux-2.6/xfs_trace.h
===================================================================
--- xfs.orig/fs/xfs/linux-2.6/xfs_trace.h 2011-06-29 11:35:45.000000000 +0200
+++ xfs/fs/xfs/linux-2.6/xfs_trace.h 2011-06-29 13:54:32.974343403 +0200
@@ -293,7 +293,7 @@ DECLARE_EVENT_CLASS(xfs_buf_class,
__entry->buffer_length = bp->b_buffer_length;
__entry->hold = atomic_read(&bp->b_hold);
__entry->pincount = atomic_read(&bp->b_pin_count);
- __entry->lockval = xfs_buf_lock_value(bp);
+ __entry->lockval = bp->b_sema.count;
__entry->flags = bp->b_flags;
__entry->caller_ip = caller_ip;
),
@@ -323,7 +323,7 @@ DEFINE_BUF_EVENT(xfs_buf_bawrite);
DEFINE_BUF_EVENT(xfs_buf_bdwrite);
DEFINE_BUF_EVENT(xfs_buf_lock);
DEFINE_BUF_EVENT(xfs_buf_lock_done);
-DEFINE_BUF_EVENT(xfs_buf_cond_lock);
+DEFINE_BUF_EVENT(xfs_buf_trylock);
DEFINE_BUF_EVENT(xfs_buf_unlock);
DEFINE_BUF_EVENT(xfs_buf_iowait);
DEFINE_BUF_EVENT(xfs_buf_iowait_done);
@@ -366,7 +366,7 @@ DECLARE_EVENT_CLASS(xfs_buf_flags_class,
__entry->flags = flags;
__entry->hold = atomic_read(&bp->b_hold);
__entry->pincount = atomic_read(&bp->b_pin_count);
- __entry->lockval = xfs_buf_lock_value(bp);
+ __entry->lockval = bp->b_sema.count;
__entry->caller_ip = caller_ip;
),
TP_printk("dev %d:%d bno 0x%llx len 0x%zx hold %d pincount %d "
@@ -409,7 +409,7 @@ TRACE_EVENT(xfs_buf_ioerror,
__entry->buffer_length = bp->b_buffer_length;
__entry->hold = atomic_read(&bp->b_hold);
__entry->pincount = atomic_read(&bp->b_pin_count);
- __entry->lockval = xfs_buf_lock_value(bp);
+ __entry->lockval = bp->b_sema.count;
__entry->error = error;
__entry->flags = bp->b_flags;
__entry->caller_ip = caller_ip;
@@ -454,7 +454,7 @@ DECLARE_EVENT_CLASS(xfs_buf_item_class,
__entry->buf_flags = bip->bli_buf->b_flags;
__entry->buf_hold = atomic_read(&bip->bli_buf->b_hold);
__entry->buf_pincount = atomic_read(&bip->bli_buf->b_pin_count);
- __entry->buf_lockval = xfs_buf_lock_value(bip->bli_buf);
+ __entry->buf_lockval = bip->bli_buf->b_sema.count;
__entry->li_desc = bip->bli_item.li_desc;
__entry->li_flags = bip->bli_item.li_flags;
),
Index: xfs/fs/xfs/quota/xfs_dquot.c
===================================================================
--- xfs.orig/fs/xfs/quota/xfs_dquot.c 2011-05-11 08:41:56.000000000 +0200
+++ xfs/fs/xfs/quota/xfs_dquot.c 2011-06-29 13:53:07.801471491 +0200
@@ -318,7 +318,7 @@ xfs_qm_init_dquot_blk(

ASSERT(tp);
ASSERT(XFS_BUF_ISBUSY(bp));
- ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
+ ASSERT(xfs_buf_islocked(bp));

d = (xfs_dqblk_t *)XFS_BUF_PTR(bp);

@@ -534,7 +534,7 @@ xfs_qm_dqtobp(
}

ASSERT(XFS_BUF_ISBUSY(bp));
- ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
+ ASSERT(xfs_buf_islocked(bp));

/*
* calculate the location of the dquot inside the buffer.
@@ -622,7 +622,7 @@ xfs_qm_dqread(
* brelse it because we have the changes incore.
*/
ASSERT(XFS_BUF_ISBUSY(bp));
- ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
+ ASSERT(xfs_buf_islocked(bp));
xfs_trans_brelse(tp, bp);

return (error);
Index: xfs/fs/xfs/xfs_buf_item.c
===================================================================
--- xfs.orig/fs/xfs/xfs_buf_item.c 2011-04-22 06:21:45.000000000 +0200
+++ xfs/fs/xfs/xfs_buf_item.c 2011-06-29 13:53:20.938066990 +0200
@@ -420,7 +420,7 @@ xfs_buf_item_unpin(

if (freed && stale) {
ASSERT(bip->bli_flags & XFS_BLI_STALE);
- ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
+ ASSERT(xfs_buf_islocked(bp));
ASSERT(!(XFS_BUF_ISDELAYWRITE(bp)));
ASSERT(XFS_BUF_ISSTALE(bp));
ASSERT(bip->bli_format.blf_flags & XFS_BLF_CANCEL);
@@ -483,7 +483,7 @@ xfs_buf_item_trylock(

if (XFS_BUF_ISPINNED(bp))
return XFS_ITEM_PINNED;
- if (!XFS_BUF_CPSEMA(bp))
+ if (!xfs_buf_trylock(bp))
return XFS_ITEM_LOCKED;

/* take a reference to the buffer. */
@@ -905,7 +905,7 @@ xfs_buf_attach_iodone(
xfs_log_item_t *head_lip;

ASSERT(XFS_BUF_ISBUSY(bp));
- ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
+ ASSERT(xfs_buf_islocked(bp));

lip->li_cb = cb;
if (XFS_BUF_FSPRIVATE(bp, void *) != NULL) {
Index: xfs/fs/xfs/xfs_log.c
===================================================================
--- xfs.orig/fs/xfs/xfs_log.c 2011-06-17 14:07:57.000000000 +0200
+++ xfs/fs/xfs/xfs_log.c 2011-06-29 13:53:33.954663139 +0200
@@ -1059,7 +1059,7 @@ xlog_alloc_log(xfs_mount_t *mp,
XFS_BUF_SET_IODONE_FUNC(bp, xlog_iodone);
XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);
ASSERT(XFS_BUF_ISBUSY(bp));
- ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
+ ASSERT(xfs_buf_islocked(bp));
log->l_xbuf = bp;

spin_lock_init(&log->l_icloglock);
@@ -1090,7 +1090,7 @@ xlog_alloc_log(xfs_mount_t *mp,
log->l_iclog_size, 0);
if (!bp)
goto out_free_iclog;
- if (!XFS_BUF_CPSEMA(bp))
+ if (!xfs_buf_trylock(bp))
ASSERT(0);
XFS_BUF_SET_IODONE_FUNC(bp, xlog_iodone);
XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);
@@ -1118,7 +1118,7 @@ xlog_alloc_log(xfs_mount_t *mp,
iclog->ic_datap = (char *)iclog->ic_data + log->l_iclog_hsize;

ASSERT(XFS_BUF_ISBUSY(iclog->ic_bp));
- ASSERT(XFS_BUF_VALUSEMA(iclog->ic_bp) <= 0);
+ ASSERT(xfs_buf_islocked(iclog->ic_bp));
init_waitqueue_head(&iclog->ic_force_wait);
init_waitqueue_head(&iclog->ic_write_wait);

Index: xfs/fs/xfs/xfs_log_recover.c
===================================================================
--- xfs.orig/fs/xfs/xfs_log_recover.c 2011-05-20 15:25:52.000000000 +0200
+++ xfs/fs/xfs/xfs_log_recover.c 2011-06-29 13:51:20.425386530 +0200
@@ -264,7 +264,7 @@ xlog_bwrite(
XFS_BUF_ZEROFLAGS(bp);
XFS_BUF_BUSY(bp);
XFS_BUF_HOLD(bp);
- XFS_BUF_PSEMA(bp, PRIBIO);
+ xfs_buf_lock(bp);
XFS_BUF_SET_COUNT(bp, BBTOB(nbblks));
XFS_BUF_SET_TARGET(bp, log->l_mp->m_logdev_targp);

Index: xfs/fs/xfs/xfs_mount.c
===================================================================
--- xfs.orig/fs/xfs/xfs_mount.c 2011-06-29 11:38:53.000000000 +0200
+++ xfs/fs/xfs/xfs_mount.c 2011-06-29 13:51:20.425386530 +0200
@@ -1941,22 +1941,19 @@ unwind:
* the superblock buffer if it can be locked without sleeping.
* If it can't then we'll return NULL.
*/
-xfs_buf_t *
+struct xfs_buf *
xfs_getsb(
- xfs_mount_t *mp,
- int flags)
+ struct xfs_mount *mp,
+ int flags)
{
- xfs_buf_t *bp;
+ struct xfs_buf *bp = mp->m_sb_bp;

- ASSERT(mp->m_sb_bp != NULL);
- bp = mp->m_sb_bp;
- if (flags & XBF_TRYLOCK) {
- if (!XFS_BUF_CPSEMA(bp)) {
+ if (!xfs_buf_trylock(bp)) {
+ if (flags & XBF_TRYLOCK)
return NULL;
- }
- } else {
- XFS_BUF_PSEMA(bp, PRIBIO);
+ xfs_buf_lock(bp);
}
+
XFS_BUF_HOLD(bp);
ASSERT(XFS_BUF_ISDONE(bp));
return bp;
Index: xfs/fs/xfs/xfs_trans_buf.c
===================================================================
--- xfs.orig/fs/xfs/xfs_trans_buf.c 2011-03-27 23:52:57.000000000 +0200
+++ xfs/fs/xfs/xfs_trans_buf.c 2011-06-29 13:53:47.084592005 +0200
@@ -160,7 +160,7 @@ xfs_trans_get_buf(xfs_trans_t *tp,
*/
bp = xfs_trans_buf_item_match(tp, target_dev, blkno, len);
if (bp != NULL) {
- ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
+ ASSERT(xfs_buf_islocked(bp));
if (XFS_FORCED_SHUTDOWN(tp->t_mountp))
XFS_BUF_SUPER_STALE(bp);

@@ -327,7 +327,7 @@ xfs_trans_read_buf(
*/
bp = xfs_trans_buf_item_match(tp, target, blkno, len);
if (bp != NULL) {
- ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
+ ASSERT(xfs_buf_islocked(bp));
ASSERT(XFS_BUF_FSPRIVATE2(bp, xfs_trans_t *) == tp);
ASSERT(XFS_BUF_FSPRIVATE(bp, void *) != NULL);
ASSERT((XFS_BUF_ISERROR(bp)) == 0);