[XFS] add infrastructure for waiting on I/O completion at inode reclaim

time

SGI-PV: 934766
SGI-Modid: xfs-linux:xfs-kern:196854a

Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>

3 files changed, 29 insertions, 14 deletions

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index bd9aba1f2353..b55cb7f02e88 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -139,7 +139,7 @@ linvfs_unwritten_convert(
         XFS_BUF_SET_FSPRIVATE(bp, NULL);
         XFS_BUF_CLR_IODONE_FUNC(bp);
         XFS_BUF_UNDATAIO(bp);
-        iput(LINVFS_GET_IP(vp));
+        vn_iowake(vp);
         pagebuf_iodone(bp, 0, 0);
 }
 
@@ -448,14 +448,7 @@ xfs_map_unwritten(
         if (!pb)
                 return -EAGAIN;
 
-        /* Take a reference to the inode to prevent it from
-         * being reclaimed while we have outstanding unwritten
-         * extent IO on it.
-         */
-        if ((igrab(inode)) != inode) {
-                pagebuf_free(pb);
-                return -EAGAIN;
-        }
+        atomic_inc(&LINVFS_GET_VP(inode)->v_iocount);
 
         /* Set the count to 1 initially, this will stop an I/O
          * completion callout which happens before we have started
diff --git a/fs/xfs/linux-2.6/xfs_vnode.c b/fs/xfs/linux-2.6/xfs_vnode.c
index 654da98de2a5..46afc86a2862 100644
--- a/fs/xfs/linux-2.6/xfs_vnode.c
+++ b/fs/xfs/linux-2.6/xfs_vnode.c
@@ -42,17 +42,33 @@ DEFINE_SPINLOCK(vnumber_lock);
  */
 #define NVSYNC                  37
 #define vptosync(v)             (&vsync[((unsigned long)v) % NVSYNC])
-sv_t vsync[NVSYNC];
+STATIC wait_queue_head_t vsync[NVSYNC];
 
 
 void
 vn_init(void)
 {
-        register sv_t *svp;
-        register int i;
+        int i;
 
-        for (svp = vsync, i = 0; i < NVSYNC; i++, svp++)
-                init_sv(svp, SV_DEFAULT, "vsy", i);
+        for (i = 0; i < NVSYNC; i++)
+                init_waitqueue_head(&vsync[i]);
+}
+
+void
+vn_iowait(
+        struct vnode    *vp)
+{
+        wait_queue_head_t *wq = vptosync(vp);
+
+        wait_event(*wq, (atomic_read(&vp->v_iocount) == 0));
+}
+
+void
+vn_iowake(
+        struct vnode    *vp)
+{
+        if (atomic_dec_and_test(&vp->v_iocount))
+                wake_up(vptosync(vp));
 }
 
 /*
@@ -111,6 +127,8 @@ vn_initialize(
         /* Initialize the first behavior and the behavior chain head. */
         vn_bhv_head_init(VN_BHV_HEAD(vp), "vnode");
 
+        atomic_set(&vp->v_iocount, 0);
+
 #ifdef  XFS_VNODE_TRACE
         vp->v_trace = ktrace_alloc(VNODE_TRACE_SIZE, KM_SLEEP);
 #endif  /* XFS_VNODE_TRACE */
diff --git a/fs/xfs/linux-2.6/xfs_vnode.h b/fs/xfs/linux-2.6/xfs_vnode.h
index 4a74569a5690..9977afa38900 100644
--- a/fs/xfs/linux-2.6/xfs_vnode.h
+++ b/fs/xfs/linux-2.6/xfs_vnode.h
@@ -80,6 +80,7 @@ typedef struct vnode {
         vnumber_t       v_number;               /* in-core vnode number */
         vn_bhv_head_t   v_bh;                   /* behavior head */
         spinlock_t      v_lock;                 /* VN_LOCK/VN_UNLOCK */
+        atomic_t        v_iocount;              /* outstanding I/O count */
 #ifdef XFS_VNODE_TRACE
         struct ktrace   *v_trace;               /* trace header structure    */
 #endif
@@ -506,6 +507,9 @@ extern int	vn_revalidate(struct vnode *);
 extern void     vn_revalidate_core(struct vnode *, vattr_t *);
 extern void     vn_remove(struct vnode *);
 
+extern void     vn_iowait(struct vnode *vp);
+extern void     vn_iowake(struct vnode *vp);
+
 static inline int vn_count(struct vnode *vp)
 {
         return atomic_read(&LINVFS_GET_IP(vp)->i_count);