Merge remote-tracking branches 'asoc/topic/ad1836', 'asoc/topic/ad193x', 'asoc/topic...

[cascardo/linux.git] / fs / aio.c

diff --git a/fs/aio.c b/fs/aio.c
index 643db8f..062a5f6 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -244,9 +244,14 @@ static void aio_free_ring(struct kioctx *ctx)
        int i;
 
        for (i = 0; i < ctx->nr_pages; i++) {
+               struct page *page;
                pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i,
                                page_count(ctx->ring_pages[i]));
-               put_page(ctx->ring_pages[i]);
+               page = ctx->ring_pages[i];
+               if (!page)
+                       continue;
+               ctx->ring_pages[i] = NULL;
+               put_page(page);
        }
 
        put_aio_ring_file(ctx);
@@ -280,18 +285,38 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
        unsigned long flags;
        int rc;
 
+       rc = 0;
+
+       /* Make sure the old page hasn't already been changed */
+       spin_lock(&mapping->private_lock);
+       ctx = mapping->private_data;
+       if (ctx) {
+               pgoff_t idx;
+               spin_lock_irqsave(&ctx->completion_lock, flags);
+               idx = old->index;
+               if (idx < (pgoff_t)ctx->nr_pages) {
+                       if (ctx->ring_pages[idx] != old)
+                               rc = -EAGAIN;
+               } else
+                       rc = -EINVAL;
+               spin_unlock_irqrestore(&ctx->completion_lock, flags);
+       } else
+               rc = -EINVAL;
+       spin_unlock(&mapping->private_lock);
+
+       if (rc != 0)
+               return rc;
+
        /* Writeback must be complete */
        BUG_ON(PageWriteback(old));
-       put_page(old);
+       get_page(new);
 
-       rc = migrate_page_move_mapping(mapping, new, old, NULL, mode);
+       rc = migrate_page_move_mapping(mapping, new, old, NULL, mode, 1);
        if (rc != MIGRATEPAGE_SUCCESS) {
-               get_page(old);
+               put_page(new);
                return rc;
        }
 
-       get_page(new);
-
        /* We can potentially race against kioctx teardown here.  Use the
         * address_space's private data lock to protect the mapping's
         * private_data.
@@ -303,13 +328,24 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
                spin_lock_irqsave(&ctx->completion_lock, flags);
                migrate_page_copy(new, old);
                idx = old->index;
-               if (idx < (pgoff_t)ctx->nr_pages)
-                       ctx->ring_pages[idx] = new;
+               if (idx < (pgoff_t)ctx->nr_pages) {
+                       /* And only do the move if things haven't changed */
+                       if (ctx->ring_pages[idx] == old)
+                               ctx->ring_pages[idx] = new;
+                       else
+                               rc = -EAGAIN;
+               } else
+                       rc = -EINVAL;
                spin_unlock_irqrestore(&ctx->completion_lock, flags);
        } else
                rc = -EBUSY;
        spin_unlock(&mapping->private_lock);
 
+       if (rc == MIGRATEPAGE_SUCCESS)
+               put_page(old);
+       else
+               put_page(new);
+
        return rc;
 }
 #endif
@@ -640,7 +676,8 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
        aio_nr += ctx->max_reqs;
        spin_unlock(&aio_nr_lock);
 
-       percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */
+       percpu_ref_get(&ctx->users);    /* io_setup() will drop this ref */
+       percpu_ref_get(&ctx->reqs);     /* free_ioctx_users() will drop this */
 
        err = ioctx_add_table(ctx, mm);
        if (err)