Merge git://git.kvack.org/~bcrl/aio-fixes

Pull aio fix from Ben LaHaise:
 "Dirty page accounting fix for aio"

* git://git.kvack.org/~bcrl/aio-fixes:
  aio: fix uncorrent dirty pages accouting when truncating AIO ring buffer

1 files changed, 14 insertions, 7 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 84a751005f5b..14b93159ef83 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -165,6 +165,15 @@ static struct vfsmount *aio_mnt;
 static const struct file_operations aio_ring_fops;
 static const struct address_space_operations aio_ctx_aops;
 
+/* Backing dev info for aio fs.
+ * -no dirty page accounting or writeback happens
+ */
+static struct backing_dev_info aio_fs_backing_dev_info = {
+        .name           = "aiofs",
+        .state          = 0,
+        .capabilities   = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_MAP_COPY,
+};
+
 static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
 {
         struct qstr this = QSTR_INIT("[aio]", 5);
@@ -176,6 +185,7 @@ static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
 
         inode->i_mapping->a_ops = &aio_ctx_aops;
         inode->i_mapping->private_data = ctx;
+        inode->i_mapping->backing_dev_info = &aio_fs_backing_dev_info;
         inode->i_size = PAGE_SIZE * nr_pages;
 
         path.dentry = d_alloc_pseudo(aio_mnt->mnt_sb, &this);
@@ -220,6 +230,9 @@ static int __init aio_setup(void)
         if (IS_ERR(aio_mnt))
                 panic("Failed to create aio fs mount.");
 
+        if (bdi_init(&aio_fs_backing_dev_info))
+                panic("Failed to init aio fs backing dev info.");
+
         kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
         kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
 
@@ -281,11 +294,6 @@ static const struct file_operations aio_ring_fops = {
         .mmap = aio_ring_mmap,
 };
 
-static int aio_set_page_dirty(struct page *page)
-{
-        return 0;
-}
-
 #if IS_ENABLED(CONFIG_MIGRATION)
 static int aio_migratepage(struct address_space *mapping, struct page *new,
                         struct page *old, enum migrate_mode mode)
@@ -357,7 +365,7 @@ out:
 #endif
 
 static const struct address_space_operations aio_ctx_aops = {
-        .set_page_dirty = aio_set_page_dirty,
+        .set_page_dirty = __set_page_dirty_no_writeback,
 #if IS_ENABLED(CONFIG_MIGRATION)
         .migratepage    = aio_migratepage,
 #endif
@@ -412,7 +420,6 @@ static int aio_setup_ring(struct kioctx *ctx)
                 pr_debug("pid(%d) page[%d]->count=%d\n",
                          current->pid, i, page_count(page));
                 SetPageUptodate(page);
-                SetPageDirty(page);
                 unlock_page(page);
 
                 ctx->ring_pages[i] = page;