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Date: Fri, 11 Jul 2008 11:13:48 +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 4/6] Replace inode flush semaphore with a completion
Use the new completion flush code to implement the inode
flush lock. Removes one of the final users of semaphores
in the XFS code base.
Version 2:
o make flock functions static inlines
o use new completion interfaces
Signed-off-by: Dave Chinner <david@...morbit.com>
---
fs/xfs/xfs_iget.c | 32 ++++++++------------------------
fs/xfs/xfs_inode.c | 11 +++++------
fs/xfs/xfs_inode.h | 25 +++++++++++++++++++++----
fs/xfs/xfs_inode_item.c | 11 +++++------
4 files changed, 39 insertions(+), 40 deletions(-)
diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index b07604b..eb4db18 100644
--- a/fs/xfs/xfs_iget.c
+++ b/fs/xfs/xfs_iget.c
@@ -216,7 +216,14 @@ finish_inode:
mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
init_waitqueue_head(&ip->i_ipin_wait);
atomic_set(&ip->i_pincount, 0);
- initnsema(&ip->i_flock, 1, "xfsfino");
+
+ /*
+ * 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(&ip->i_flush);
+ complete(&ip->i_flush);
if (lock_flags)
xfs_ilock(ip, lock_flags);
@@ -775,26 +782,3 @@ xfs_isilocked(
}
#endif
-/*
- * The following three routines simply manage the i_flock
- * semaphore embedded in the inode. This semaphore synchronizes
- * processes attempting to flush the in-core inode back to disk.
- */
-void
-xfs_iflock(xfs_inode_t *ip)
-{
- psema(&(ip->i_flock), PINOD|PLTWAIT);
-}
-
-int
-xfs_iflock_nowait(xfs_inode_t *ip)
-{
- return (cpsema(&(ip->i_flock)));
-}
-
-void
-xfs_ifunlock(xfs_inode_t *ip)
-{
- ASSERT(issemalocked(&(ip->i_flock)));
- vsema(&(ip->i_flock));
-}
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index bedc661..1047bdc 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2630,7 +2630,6 @@ xfs_idestroy(
xfs_idestroy_fork(ip, XFS_ATTR_FORK);
mrfree(&ip->i_lock);
mrfree(&ip->i_iolock);
- freesema(&ip->i_flock);
#ifdef XFS_INODE_TRACE
ktrace_free(ip->i_trace);
@@ -3048,10 +3047,10 @@ cluster_corrupt_out:
/*
* xfs_iflush() will write a modified inode's changes out to the
* inode's on disk home. The caller must have the inode lock held
- * in at least shared mode and the inode flush semaphore must be
- * held as well. The inode lock will still be held upon return from
+ * in at least shared mode and the inode flush completion must be
+ * active as well. The inode lock will still be held upon return from
* the call and the caller is free to unlock it.
- * The inode flush lock will be unlocked when the inode reaches the disk.
+ * The inode flush will be completed when the inode reaches the disk.
* The flags indicate how the inode's buffer should be written out.
*/
int
@@ -3070,7 +3069,7 @@ xfs_iflush(
XFS_STATS_INC(xs_iflush_count);
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
- ASSERT(issemalocked(&(ip->i_flock)));
+ ASSERT(!completion_done(&ip->i_flush));
ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
ip->i_d.di_nextents > ip->i_df.if_ext_max);
@@ -3233,7 +3232,7 @@ xfs_iflush_int(
#endif
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
- ASSERT(issemalocked(&(ip->i_flock)));
+ ASSERT(!completion_done(&ip->i_flush));
ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
ip->i_d.di_nextents > ip->i_df.if_ext_max);
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 17a04b6..086282d 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -223,7 +223,7 @@ typedef struct xfs_inode {
struct xfs_inode_log_item *i_itemp; /* logging information */
mrlock_t i_lock; /* inode lock */
mrlock_t i_iolock; /* inode IO lock */
- sema_t i_flock; /* inode flush lock */
+ struct completion i_flush; /* inode flush completion q */
atomic_t i_pincount; /* inode pin count */
wait_queue_head_t i_ipin_wait; /* inode pinning wait queue */
spinlock_t i_flags_lock; /* inode i_flags lock */
@@ -473,11 +473,8 @@ int xfs_ilock_nowait(xfs_inode_t *, uint);
void xfs_iunlock(xfs_inode_t *, uint);
void xfs_ilock_demote(xfs_inode_t *, uint);
int xfs_isilocked(xfs_inode_t *, uint);
-void xfs_iflock(xfs_inode_t *);
-int xfs_iflock_nowait(xfs_inode_t *);
uint xfs_ilock_map_shared(xfs_inode_t *);
void xfs_iunlock_map_shared(xfs_inode_t *, uint);
-void xfs_ifunlock(xfs_inode_t *);
void xfs_ireclaim(xfs_inode_t *);
int xfs_finish_reclaim(xfs_inode_t *, int, int);
int xfs_finish_reclaim_all(struct xfs_mount *, int);
@@ -570,6 +567,26 @@ extern struct kmem_zone *xfs_ifork_zone;
extern struct kmem_zone *xfs_inode_zone;
extern struct kmem_zone *xfs_ili_zone;
+/*
+ * Manage the i_flush queue embedded in the inode. This completion
+ * queue synchronizes processes attempting to flush the in-core
+ * inode back to disk.
+ */
+static inline void xfs_iflock(xfs_inode_t *ip)
+{
+ wait_for_completion(&ip->i_flush);
+}
+
+static inline int xfs_iflock_nowait(xfs_inode_t *ip)
+{
+ return try_wait_for_completion(&ip->i_flush);
+}
+
+static inline void xfs_ifunlock(xfs_inode_t *ip)
+{
+ complete(&ip->i_flush);
+}
+
#endif /* __KERNEL__ */
#endif /* __XFS_INODE_H__ */
diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index 0eee08a..97c7452 100644
--- a/fs/xfs/xfs_inode_item.c
+++ b/fs/xfs/xfs_inode_item.c
@@ -779,11 +779,10 @@ xfs_inode_item_pushbuf(
ASSERT(iip->ili_push_owner == current_pid());
/*
- * If flushlock isn't locked anymore, chances are that the
- * inode flush completed and the inode was taken off the AIL.
- * So, just get out.
+ * If a flush is not in progress anymore, chances are that the
+ * inode was taken off the AIL. So, just get out.
*/
- if (!issemalocked(&(ip->i_flock)) ||
+ if (completion_done(&ip->i_flush) ||
((iip->ili_item.li_flags & XFS_LI_IN_AIL) == 0)) {
iip->ili_pushbuf_flag = 0;
xfs_iunlock(ip, XFS_ILOCK_SHARED);
@@ -805,7 +804,7 @@ xfs_inode_item_pushbuf(
* If not, we can flush it async.
*/
dopush = ((iip->ili_item.li_flags & XFS_LI_IN_AIL) &&
- issemalocked(&(ip->i_flock)));
+ !completion_done(&ip->i_flush));
iip->ili_pushbuf_flag = 0;
xfs_iunlock(ip, XFS_ILOCK_SHARED);
xfs_buftrace("INODE ITEM PUSH", bp);
@@ -858,7 +857,7 @@ xfs_inode_item_push(
ip = iip->ili_inode;
ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED));
- ASSERT(issemalocked(&(ip->i_flock)));
+ ASSERT(!completion_done(&ip->i_flush));
/*
* Since we were able to lock the inode's flush lock and
* we found it on the AIL, the inode must be dirty. This
--
1.5.6
--
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