1 files changed, 59 insertions, 58 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index df0cba239dd5..655bf4a78afe 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000-2004 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2000-2005 Silicon Graphics, Inc.  All Rights Reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of version 2 of the GNU General Public License as
@@ -54,6 +54,7 @@
 #include <linux/percpu.h>
 #include <linux/blkdev.h>
 #include <linux/hash.h>
+#include <linux/kthread.h>
 
 #include "xfs_linux.h"
 
@@ -67,7 +68,7 @@ STATIC int xfsbufd_wakeup(int, unsigned int);
 STATIC void pagebuf_delwri_queue(xfs_buf_t *, int);
 
 STATIC struct workqueue_struct *xfslogd_workqueue;
-STATIC struct workqueue_struct *xfsdatad_workqueue;
+struct workqueue_struct *xfsdatad_workqueue;
 
 /*
  * Pagebuf debugging
@@ -590,8 +591,10 @@ found:
                 PB_SET_OWNER(pb);
         }
 
-        if (pb->pb_flags & PBF_STALE)
+        if (pb->pb_flags & PBF_STALE) {
+                ASSERT((pb->pb_flags & _PBF_DELWRI_Q) == 0);
                 pb->pb_flags &= PBF_MAPPED;
+        }
         PB_TRACE(pb, "got_lock", 0);
         XFS_STATS_INC(pb_get_locked);
         return (pb);
@@ -700,25 +703,6 @@ xfs_buf_read_flags(
 }
 
 /*
- * Create a skeletal pagebuf (no pages associated with it).
- */
-xfs_buf_t *
-pagebuf_lookup(
-        xfs_buftarg_t           *target,
-        loff_t                  ioff,
-        size_t                  isize,
-        page_buf_flags_t        flags)
-{
-        xfs_buf_t               *pb;
-
-        pb = pagebuf_allocate(flags);
-        if (pb) {
-                _pagebuf_initialize(pb, target, ioff, isize, flags);
-        }
-        return pb;
-}
-
-/*
  * If we are not low on memory then do the readahead in a deadlock
  * safe manner.
  */
@@ -913,22 +897,23 @@ pagebuf_rele(
                         do_free = 0;
                 }
 
-                if (pb->pb_flags & PBF_DELWRI) {
-                        pb->pb_flags |= PBF_ASYNC;
-                        atomic_inc(&pb->pb_hold);
-                        pagebuf_delwri_queue(pb, 0);
-                        do_free = 0;
-                } else if (pb->pb_flags & PBF_FS_MANAGED) {
+                if (pb->pb_flags & PBF_FS_MANAGED) {
                         do_free = 0;
                 }
 
                 if (do_free) {
+                        ASSERT((pb->pb_flags & (PBF_DELWRI|_PBF_DELWRI_Q)) == 0);
                         list_del_init(&pb->pb_hash_list);
                         spin_unlock(&hash->bh_lock);
                         pagebuf_free(pb);
                 } else {
                         spin_unlock(&hash->bh_lock);
                 }
+        } else {
+                /*
+                 * Catch reference count leaks
+                 */
+                ASSERT(atomic_read(&pb->pb_hold) >= 0);
         }
 }
 
@@ -1006,13 +991,24 @@ pagebuf_lock(
  *      pagebuf_unlock
  *
  *      pagebuf_unlock releases the lock on the buffer object created by
- *      pagebuf_lock or pagebuf_cond_lock (not any
- *      pinning of underlying pages created by pagebuf_pin).
+ *      pagebuf_lock or pagebuf_cond_lock (not any pinning of underlying pages
+ *      created by pagebuf_pin).
+ *
+ *      If the buffer is marked delwri but is not queued, do so before we
+ *      unlock the buffer as we need to set flags correctly. We also need to
+ *      take a reference for the delwri queue because the unlocker is going to
+ *      drop their's and they don't know we just queued it.
  */
 void
 pagebuf_unlock(                         /* unlock buffer                */
         xfs_buf_t               *pb)    /* buffer to unlock             */
 {
+        if ((pb->pb_flags & (PBF_DELWRI|_PBF_DELWRI_Q)) == PBF_DELWRI) {
+                atomic_inc(&pb->pb_hold);
+                pb->pb_flags |= PBF_ASYNC;
+                pagebuf_delwri_queue(pb, 0);
+        }
+
         PB_CLEAR_OWNER(pb);
         up(&pb->pb_sema);
         PB_TRACE(pb, "unlock", 0);
@@ -1249,8 +1245,8 @@ bio_end_io_pagebuf(
         int                     error)
 {
         xfs_buf_t               *pb = (xfs_buf_t *)bio->bi_private;
-        unsigned int            i, blocksize = pb->pb_target->pbr_bsize;
-        struct bio_vec          *bvec = bio->bi_io_vec;
+        unsigned int            blocksize = pb->pb_target->pbr_bsize;
+        struct bio_vec          *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
 
         if (bio->bi_size)
                 return 1;
@@ -1258,10 +1254,12 @@ bio_end_io_pagebuf(
         if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
                 pb->pb_error = EIO;
 
-        for (i = 0; i < bio->bi_vcnt; i++, bvec++) {
+        do {
                 struct page     *page = bvec->bv_page;
 
-                if (pb->pb_error) {
+                if (unlikely(pb->pb_error)) {
+                        if (pb->pb_flags & PBF_READ)
+                                ClearPageUptodate(page);
                         SetPageError(page);
                 } else if (blocksize == PAGE_CACHE_SIZE) {
                         SetPageUptodate(page);
@@ -1270,10 +1268,13 @@ bio_end_io_pagebuf(
                         set_page_region(page, bvec->bv_offset, bvec->bv_len);
                 }
 
+                if (--bvec >= bio->bi_io_vec)
+                        prefetchw(&bvec->bv_page->flags);
+
                 if (_pagebuf_iolocked(pb)) {
                         unlock_page(page);
                 }
-        }
+        } while (bvec >= bio->bi_io_vec);
 
         _pagebuf_iodone(pb, 1);
         bio_put(bio);
@@ -1511,6 +1512,11 @@ again:
                         ASSERT(btp == bp->pb_target);
                         if (!(bp->pb_flags & PBF_FS_MANAGED)) {
                                 spin_unlock(&hash->bh_lock);
+                                /*
+                                 * Catch superblock reference count leaks
+                                 * immediately
+                                 */
+                                BUG_ON(bp->pb_bn == 0);
                                 delay(100);
                                 goto again;
                         }
@@ -1686,17 +1692,20 @@ pagebuf_delwri_queue(
         int                     unlock)
 {
         PB_TRACE(pb, "delwri_q", (long)unlock);
-        ASSERT(pb->pb_flags & PBF_DELWRI);
+        ASSERT((pb->pb_flags & (PBF_DELWRI|PBF_ASYNC)) ==
+                                        (PBF_DELWRI|PBF_ASYNC));
 
         spin_lock(&pbd_delwrite_lock);
         /* If already in the queue, dequeue and place at tail */
         if (!list_empty(&pb->pb_list)) {
+                ASSERT(pb->pb_flags & _PBF_DELWRI_Q);
                 if (unlock) {
                         atomic_dec(&pb->pb_hold);
                 }
                 list_del(&pb->pb_list);
         }
 
+        pb->pb_flags |= _PBF_DELWRI_Q;
         list_add_tail(&pb->pb_list, &pbd_delwrite_queue);
         pb->pb_queuetime = jiffies;
         spin_unlock(&pbd_delwrite_lock);
@@ -1713,10 +1722,11 @@ pagebuf_delwri_dequeue(
 
         spin_lock(&pbd_delwrite_lock);
         if ((pb->pb_flags & PBF_DELWRI) && !list_empty(&pb->pb_list)) {
+                ASSERT(pb->pb_flags & _PBF_DELWRI_Q);
                 list_del_init(&pb->pb_list);
                 dequeued = 1;
         }
-        pb->pb_flags &= ~PBF_DELWRI;
+        pb->pb_flags &= ~(PBF_DELWRI|_PBF_DELWRI_Q);
         spin_unlock(&pbd_delwrite_lock);
 
         if (dequeued)
@@ -1733,9 +1743,7 @@ pagebuf_runall_queues(
 }
 
 /* Defines for pagebuf daemon */
-STATIC DECLARE_COMPLETION(xfsbufd_done);
 STATIC struct task_struct *xfsbufd_task;
-STATIC int xfsbufd_active;
 STATIC int xfsbufd_force_flush;
 STATIC int xfsbufd_force_sleep;
 
@@ -1761,14 +1769,8 @@ xfsbufd(
         xfs_buftarg_t           *target;
         xfs_buf_t               *pb, *n;
 
-        /*  Set up the thread  */
-        daemonize("xfsbufd");
         current->flags |= PF_MEMALLOC;
 
-        xfsbufd_task = current;
-        xfsbufd_active = 1;
-        barrier();
-
         INIT_LIST_HEAD(&tmp);
         do {
                 if (unlikely(freezing(current))) {
@@ -1795,7 +1797,7 @@ xfsbufd(
                                         break;
                                 }
 
-                                pb->pb_flags &= ~PBF_DELWRI;
+                                pb->pb_flags &= ~(PBF_DELWRI|_PBF_DELWRI_Q);
                                 pb->pb_flags |= PBF_WRITE;
                                 list_move(&pb->pb_list, &tmp);
                         }
@@ -1816,9 +1818,9 @@ xfsbufd(
                         purge_addresses();
 
                 xfsbufd_force_flush = 0;
-        } while (xfsbufd_active);
+        } while (!kthread_should_stop());
 
-        complete_and_exit(&xfsbufd_done, 0);
+        return 0;
 }
 
 /*
@@ -1845,15 +1847,13 @@ xfs_flush_buftarg(
                 if (pb->pb_target != target)
                         continue;
 
-                ASSERT(pb->pb_flags & PBF_DELWRI);
+                ASSERT(pb->pb_flags & (PBF_DELWRI|_PBF_DELWRI_Q));
                 PB_TRACE(pb, "walkq2", (long)pagebuf_ispin(pb));
                 if (pagebuf_ispin(pb)) {
                         pincount++;
                         continue;
                 }
 
-                pb->pb_flags &= ~PBF_DELWRI;
-                pb->pb_flags |= PBF_WRITE;
                 list_move(&pb->pb_list, &tmp);
         }
         spin_unlock(&pbd_delwrite_lock);
@@ -1862,12 +1862,14 @@ xfs_flush_buftarg(
          * Dropped the delayed write list lock, now walk the temporary list
          */
         list_for_each_entry_safe(pb, n, &tmp, pb_list) {
+                pagebuf_lock(pb);
+                pb->pb_flags &= ~(PBF_DELWRI|_PBF_DELWRI_Q);
+                pb->pb_flags |= PBF_WRITE;
                 if (wait)
                         pb->pb_flags &= ~PBF_ASYNC;
                 else
                         list_del_init(&pb->pb_list);
 
-                pagebuf_lock(pb);
                 pagebuf_iostrategy(pb);
         }
 
@@ -1901,9 +1903,11 @@ xfs_buf_daemons_start(void)
         if (!xfsdatad_workqueue)
                 goto out_destroy_xfslogd_workqueue;
 
-        error = kernel_thread(xfsbufd, NULL, CLONE_FS|CLONE_FILES);
-        if (error < 0)
+        xfsbufd_task = kthread_run(xfsbufd, NULL, "xfsbufd");
+        if (IS_ERR(xfsbufd_task)) {
+                error = PTR_ERR(xfsbufd_task);
                 goto out_destroy_xfsdatad_workqueue;
+        }
         return 0;
 
  out_destroy_xfsdatad_workqueue:
@@ -1920,10 +1924,7 @@ xfs_buf_daemons_start(void)
 STATIC void
 xfs_buf_daemons_stop(void)
 {
-        xfsbufd_active = 0;
-        barrier();
-        wait_for_completion(&xfsbufd_done);
-
+        kthread_stop(xfsbufd_task);
         destroy_workqueue(xfslogd_workqueue);
         destroy_workqueue(xfsdatad_workqueue);
 }