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LU-6215 llite: remove obsolete conditional code
[fs/lustre-release.git] / lustre / llite / rw26.c
index a90b9dd..b362532 100644 (file)
@@ -27,7 +27,7 @@
  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2011, 2012, Intel Corporation.
+ * Copyright (c) 2011, 2014, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
@@ -62,9 +62,8 @@
 
 #define DEBUG_SUBSYSTEM S_LLITE
 
-#include <lustre_lite.h>
 #include "llite_internal.h"
-#include <linux/lustre_compat25.h>
+#include <lustre_compat.h>
 
 /**
  * Implements Linux VM address_space::invalidatepage() method. This method is
  * aligned truncate). Lustre leaves partially truncated page in the cache,
  * relying on struct inode::i_size to limit further accesses.
  */
-static void ll_invalidatepage(struct page *vmpage, unsigned long offset)
+static void ll_invalidatepage(struct page *vmpage,
+#ifdef HAVE_INVALIDATE_RANGE
+                               unsigned int offset, unsigned int length
+#else
+                               unsigned long offset
+#endif
+                            )
 {
         struct inode     *inode;
         struct lu_env    *env;
         struct cl_page   *page;
         struct cl_object *obj;
 
-        int refcheck;
+       __u16 refcheck;
 
         LASSERT(PageLocked(vmpage));
         LASSERT(!PageWriteback(vmpage));
 
-        /*
-         * It is safe to not check anything in invalidatepage/releasepage
-         * below because they are run with page locked and all our io is
-         * happening with locked page too
-         */
-        if (offset == 0) {
+       /*
+        * It is safe to not check anything in invalidatepage/releasepage
+        * below because they are run with page locked and all our io is
+        * happening with locked page too
+        */
+#ifdef HAVE_INVALIDATE_RANGE
+       if (offset == 0 && length == PAGE_CACHE_SIZE) {
+#else
+       if (offset == 0) {
+#endif
                 env = cl_env_get(&refcheck);
                 if (!IS_ERR(env)) {
                         inode = vmpage->mapping->host;
@@ -101,11 +110,7 @@ static void ll_invalidatepage(struct page *vmpage, unsigned long offset)
                         if (obj != NULL) {
                                 page = cl_vmpage_page(vmpage, obj);
                                 if (page != NULL) {
-                                        lu_ref_add(&page->cp_reference,
-                                                   "delete", vmpage);
                                         cl_page_delete(env, page);
-                                        lu_ref_del(&page->cp_reference,
-                                                   "delete", vmpage);
                                         cl_page_put(env, page);
                                 }
                         } else
@@ -122,139 +127,82 @@ static void ll_invalidatepage(struct page *vmpage, unsigned long offset)
 #endif
 static int ll_releasepage(struct page *vmpage, RELEASEPAGE_ARG_TYPE gfp_mask)
 {
-        struct cl_env_nest nest;
-        struct lu_env     *env;
-        struct cl_object  *obj;
-        struct cl_page    *page;
-        struct address_space *mapping;
-        int result;
+       struct lu_env           *env;
+       void                    *cookie;
+       struct cl_object        *obj;
+       struct cl_page          *page;
+       struct address_space    *mapping;
+       int result = 0;
+
+       LASSERT(PageLocked(vmpage));
+       if (PageWriteback(vmpage) || PageDirty(vmpage))
+               return 0;
+
+       mapping = vmpage->mapping;
+       if (mapping == NULL)
+               return 1;
+
+       obj = ll_i2info(mapping->host)->lli_clob;
+       if (obj == NULL)
+               return 1;
+
+       /* 1 for caller, 1 for cl_page and 1 for page cache */
+       if (page_count(vmpage) > 3)
+               return 0;
+
+       page = cl_vmpage_page(vmpage, obj);
+       if (page == NULL)
+               return 1;
+
+       cookie = cl_env_reenter();
+       env = cl_env_percpu_get();
+       LASSERT(!IS_ERR(env));
+
+       if (!cl_page_in_use(page)) {
+               result = 1;
+               cl_page_delete(env, page);
+       }
 
-        LASSERT(PageLocked(vmpage));
-        if (PageWriteback(vmpage) || PageDirty(vmpage))
-                return 0;
-
-        mapping = vmpage->mapping;
-        if (mapping == NULL)
-                return 1;
-
-        obj = ll_i2info(mapping->host)->lli_clob;
-        if (obj == NULL)
-                return 1;
-
-        /* 1 for page allocator, 1 for cl_page and 1 for page cache */
-        if (page_count(vmpage) > 3)
-                return 0;
-
-        /* TODO: determine what gfp should be used by @gfp_mask. */
-        env = cl_env_nested_get(&nest);
-        if (IS_ERR(env))
-                /* If we can't allocate an env we won't call cl_page_put()
-                 * later on which further means it's impossible to drop
-                 * page refcount by cl_page, so ask kernel to not free
-                 * this page. */
-                return 0;
-
-        page = cl_vmpage_page(vmpage, obj);
-        result = page == NULL;
-        if (page != NULL) {
-                if (!cl_page_in_use(page)) {
-                        result = 1;
-                        cl_page_delete(env, page);
-                }
-                cl_page_put(env, page);
-        }
-        cl_env_nested_put(&nest, env);
-        return result;
-}
+       /* To use percpu env array, the call path can not be rescheduled;
+        * otherwise percpu array will be messed if ll_releaspage() called
+        * again on the same CPU.
+        *
+        * If this page holds the last refc of cl_object, the following
+        * call path may cause reschedule:
+        *   cl_page_put -> cl_page_free -> cl_object_put ->
+        *     lu_object_put -> lu_object_free -> lov_delete_raid0.
+        *
+        * However, the kernel can't get rid of this inode until all pages have
+        * been cleaned up. Now that we hold page lock here, it's pretty safe
+        * that we won't get into object delete path.
+        */
+       LASSERT(cl_object_refc(obj) > 1);
+       cl_page_put(env, page);
 
-static int ll_set_page_dirty(struct page *vmpage)
-{
-#if 0
-        struct cl_page    *page = vvp_vmpage_page_transient(vmpage);
-        struct vvp_object *obj  = cl_inode2vvp(vmpage->mapping->host);
-        struct vvp_page   *cpg;
-
-        /*
-         * XXX should page method be called here?
-         */
-        LASSERT(&obj->co_cl == page->cp_obj);
-        cpg = cl2vvp_page(cl_page_at(page, &vvp_device_type));
-        /*
-         * XXX cannot do much here, because page is possibly not locked:
-         * sys_munmap()->...
-         *     ->unmap_page_range()->zap_pte_range()->set_page_dirty().
-         */
-        vvp_write_pending(obj, cpg);
-#endif
-        RETURN(__set_page_dirty_nobuffers(vmpage));
+       cl_env_percpu_put(env);
+       cl_env_reexit(cookie);
+       return result;
 }
 
 #define MAX_DIRECTIO_SIZE 2*1024*1024*1024UL
 
-static inline int ll_get_user_pages(int rw, unsigned long user_addr,
-                                    size_t size, struct page ***pages,
-                                    int *max_pages)
-{
-        int result = -ENOMEM;
-
-        /* set an arbitrary limit to prevent arithmetic overflow */
-        if (size > MAX_DIRECTIO_SIZE) {
-                *pages = NULL;
-                return -EFBIG;
-        }
-
-       *max_pages = (user_addr + size + PAGE_CACHE_SIZE - 1) >>
-                    PAGE_CACHE_SHIFT;
-       *max_pages -= user_addr >> PAGE_CACHE_SHIFT;
-
-        OBD_ALLOC_LARGE(*pages, *max_pages * sizeof(**pages));
-        if (*pages) {
-                down_read(&current->mm->mmap_sem);
-                result = get_user_pages(current, current->mm, user_addr,
-                                        *max_pages, (rw == READ), 0, *pages,
-                                        NULL);
-                up_read(&current->mm->mmap_sem);
-                if (unlikely(result <= 0))
-                        OBD_FREE_LARGE(*pages, *max_pages * sizeof(**pages));
-        }
-
-        return result;
-}
-
-/*  ll_free_user_pages - tear down page struct array
- *  @pages: array of page struct pointers underlying target buffer */
-static void ll_free_user_pages(struct page **pages, int npages, int do_dirty)
-{
-        int i;
-
-        for (i = 0; i < npages; i++) {
-                if (pages[i] == NULL)
-                        break;
-                if (do_dirty)
-                        set_page_dirty_lock(pages[i]);
-                page_cache_release(pages[i]);
-        }
-
-        OBD_FREE_LARGE(pages, npages * sizeof(*pages));
-}
-
 ssize_t ll_direct_rw_pages(const struct lu_env *env, struct cl_io *io,
                            int rw, struct inode *inode,
                            struct ll_dio_pages *pv)
 {
-        struct cl_page    *clp;
-        struct cl_2queue  *queue;
-        struct cl_object  *obj = io->ci_obj;
-        int i;
-        ssize_t rc = 0;
-        loff_t file_offset  = pv->ldp_start_offset;
-        long size           = pv->ldp_size;
-        int page_count      = pv->ldp_nr;
-        struct page **pages = pv->ldp_pages;
-        long page_size      = cl_page_size(obj);
-        bool do_io;
-        int  io_pages       = 0;
-        ENTRY;
+       struct cl_page    *clp;
+       struct cl_2queue  *queue;
+       struct cl_object  *obj = io->ci_obj;
+       int i;
+       ssize_t rc = 0;
+       loff_t file_offset  = pv->ldp_start_offset;
+       size_t size         = pv->ldp_size;
+       int page_count      = pv->ldp_nr;
+       struct page **pages = pv->ldp_pages;
+       size_t page_size    = cl_page_size(obj);
+       bool do_io;
+       int  io_pages       = 0;
+       ENTRY;
 
         queue = &io->ci_queue;
         cl_2queue_init(queue);
@@ -282,7 +230,7 @@ ssize_t ll_direct_rw_pages(const struct lu_env *env, struct cl_io *io,
                 /* check the page type: if the page is a host page, then do
                  * write directly */
                 if (clp->cp_type == CPT_CACHEABLE) {
-                       struct page *vmpage = cl_page_vmpage(env, clp);
+                       struct page *vmpage = cl_page_vmpage(clp);
                        struct page *src_page;
                        struct page *dst_page;
                         void       *src;
@@ -344,20 +292,40 @@ ssize_t ll_direct_rw_pages(const struct lu_env *env, struct cl_io *io,
 }
 EXPORT_SYMBOL(ll_direct_rw_pages);
 
-static ssize_t ll_direct_IO_26_seg(const struct lu_env *env, struct cl_io *io,
-                                   int rw, struct inode *inode,
-                                   struct address_space *mapping,
-                                   size_t size, loff_t file_offset,
-                                   struct page **pages, int page_count)
+static ssize_t
+ll_direct_IO_seg(const struct lu_env *env, struct cl_io *io, int rw,
+                struct inode *inode, size_t size, loff_t file_offset,
+                struct page **pages, int page_count)
+{
+       struct ll_dio_pages pvec = { .ldp_pages         = pages,
+                                    .ldp_nr            = page_count,
+                                    .ldp_size          = size,
+                                    .ldp_offsets       = NULL,
+                                    .ldp_start_offset  = file_offset
+                                  };
+
+       return ll_direct_rw_pages(env, io, rw, inode, &pvec);
+}
+
+/*  ll_free_user_pages - tear down page struct array
+ *  @pages: array of page struct pointers underlying target buffer */
+static void ll_free_user_pages(struct page **pages, int npages, int do_dirty)
 {
-    struct ll_dio_pages pvec = { .ldp_pages        = pages,
-                                 .ldp_nr           = page_count,
-                                 .ldp_size         = size,
-                                 .ldp_offsets      = NULL,
-                                 .ldp_start_offset = file_offset
-                               };
-
-    return ll_direct_rw_pages(env, io, rw, inode, &pvec);
+       int i;
+
+       for (i = 0; i < npages; i++) {
+               if (pages[i] == NULL)
+                       break;
+               if (do_dirty)
+                       set_page_dirty_lock(pages[i]);
+               page_cache_release(pages[i]);
+       }
+
+#if defined(HAVE_DIRECTIO_ITER) || defined(HAVE_IOV_ITER_RW)
+       kvfree(pages);
+#else
+       OBD_FREE_LARGE(pages, npages * sizeof(*pages));
+#endif
 }
 
 #ifdef KMALLOC_MAX_SIZE
@@ -373,58 +341,187 @@ static ssize_t ll_direct_IO_26_seg(const struct lu_env *env, struct cl_io *io,
  * up to 22MB for 128kB kmalloc and up to 682MB for 4MB kmalloc. */
 #define MAX_DIO_SIZE ((MAX_MALLOC / sizeof(struct brw_page) * PAGE_CACHE_SIZE) & \
                      ~(DT_MAX_BRW_SIZE - 1))
-static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
-                               const struct iovec *iov, loff_t file_offset,
-                               unsigned long nr_segs)
+
+#ifndef HAVE_IOV_ITER_RW
+# define iov_iter_rw(iter)     rw
+#endif
+
+#if defined(HAVE_DIRECTIO_ITER) || defined(HAVE_IOV_ITER_RW)
+static ssize_t
+ll_direct_IO(
+# ifndef HAVE_IOV_ITER_RW
+            int rw,
+# endif
+            struct kiocb *iocb, struct iov_iter *iter,
+            loff_t file_offset)
 {
-        struct lu_env *env;
-        struct cl_io *io;
-        struct file *file = iocb->ki_filp;
-        struct inode *inode = file->f_mapping->host;
-        struct ccc_object *obj = cl_inode2ccc(inode);
-        long count = iov_length(iov, nr_segs);
-        long tot_bytes = 0, result = 0;
-        struct ll_inode_info *lli = ll_i2info(inode);
-        unsigned long seg = 0;
-        long size = MAX_DIO_SIZE;
-        int refcheck;
-        ENTRY;
-
-       if (!lli->lli_has_smd)
-                RETURN(-EBADF);
+       struct lu_env *env;
+       struct cl_io *io;
+       struct file *file = iocb->ki_filp;
+       struct inode *inode = file->f_mapping->host;
+       ssize_t count = iov_iter_count(iter);
+       ssize_t tot_bytes = 0, result = 0;
+       size_t size = MAX_DIO_SIZE;
+       __u16 refcheck;
+
+       /* FIXME: io smaller than PAGE_SIZE is broken on ia64 ??? */
+       if ((file_offset & ~PAGE_MASK) || (count & ~PAGE_MASK))
+               return -EINVAL;
+
+       CDEBUG(D_VFSTRACE, "VFS Op:inode="DFID"(%p), size=%zd (max %lu), "
+              "offset=%lld=%llx, pages %zd (max %lu)\n",
+              PFID(ll_inode2fid(inode)), inode, count, MAX_DIO_SIZE,
+              file_offset, file_offset, count >> PAGE_CACHE_SHIFT,
+              MAX_DIO_SIZE >> PAGE_CACHE_SHIFT);
+
+       /* Check that all user buffers are aligned as well */
+       if (iov_iter_alignment(iter) & ~PAGE_MASK)
+               return -EINVAL;
+
+       env = cl_env_get(&refcheck);
+       LASSERT(!IS_ERR(env));
+       io = vvp_env_io(env)->vui_cl.cis_io;
+       LASSERT(io != NULL);
+
+       /* 0. Need locking between buffered and direct access. and race with
+        *    size changing by concurrent truncates and writes.
+        * 1. Need inode mutex to operate transient pages.
+        */
+       if (iov_iter_rw(iter) == READ)
+               mutex_lock(&inode->i_mutex);
+
+       while (iov_iter_count(iter)) {
+               struct page **pages;
+               size_t offs;
+
+               count = min_t(size_t, iov_iter_count(iter), size);
+               if (iov_iter_rw(iter) == READ) {
+                       if (file_offset >= i_size_read(inode))
+                               break;
+
+                       if (file_offset + count > i_size_read(inode))
+                               count = i_size_read(inode) - file_offset;
+               }
+
+               result = iov_iter_get_pages_alloc(iter, &pages, count, &offs);
+               if (likely(result > 0)) {
+                       int n = DIV_ROUND_UP(result + offs, PAGE_SIZE);
+
+                       result = ll_direct_IO_seg(env, io, iov_iter_rw(iter),
+                                                 inode, result, file_offset,
+                                                 pages, n);
+                       ll_free_user_pages(pages, n,
+                                          iov_iter_rw(iter) == READ);
+
+               }
+               if (unlikely(result <= 0)) {
+                       /* If we can't allocate a large enough buffer
+                        * for the request, shrink it to a smaller
+                        * PAGE_SIZE multiple and try again.
+                        * We should always be able to kmalloc for a
+                        * page worth of page pointers = 4MB on i386. */
+                       if (result == -ENOMEM &&
+                           size > (PAGE_CACHE_SIZE / sizeof(*pages)) *
+                                   PAGE_CACHE_SIZE) {
+                               size = ((((size / 2) - 1) |
+                                       ~PAGE_MASK) + 1) & PAGE_MASK;
+                               CDEBUG(D_VFSTRACE, "DIO size now %zu\n",
+                                      size);
+                               continue;
+                       }
+
+                       GOTO(out, result);
+               }
+
+               iov_iter_advance(iter, result);
+               tot_bytes += result;
+               file_offset += result;
+       }
+out:
+       if (iov_iter_rw(iter) == READ)
+               mutex_unlock(&inode->i_mutex);
+
+       if (tot_bytes > 0) {
+               struct vvp_io *vio = vvp_env_io(env);
+
+               /* no commit async for direct IO */
+               vio->u.write.vui_written += tot_bytes;
+       }
+
+       cl_env_put(env, &refcheck);
+       return tot_bytes ? : result;
+}
+#else /* !HAVE_DIRECTIO_ITER && !HAVE_IOV_ITER_RW */
+
+static inline int ll_get_user_pages(int rw, unsigned long user_addr,
+                                   size_t size, struct page ***pages,
+                                   int *max_pages)
+{
+       int result = -ENOMEM;
+
+       /* set an arbitrary limit to prevent arithmetic overflow */
+       if (size > MAX_DIRECTIO_SIZE) {
+               *pages = NULL;
+               return -EFBIG;
+       }
+
+       *max_pages = (user_addr + size + PAGE_CACHE_SIZE - 1) >>
+                     PAGE_CACHE_SHIFT;
+       *max_pages -= user_addr >> PAGE_CACHE_SHIFT;
+
+       OBD_ALLOC_LARGE(*pages, *max_pages * sizeof(**pages));
+       if (*pages) {
+               down_read(&current->mm->mmap_sem);
+               result = get_user_pages(current, current->mm, user_addr,
+                                       *max_pages, (rw == READ), 0, *pages,
+                                       NULL);
+               up_read(&current->mm->mmap_sem);
+               if (unlikely(result <= 0))
+                       OBD_FREE_LARGE(*pages, *max_pages * sizeof(**pages));
+       }
+
+       return result;
+}
+
+static ssize_t
+ll_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
+            loff_t file_offset, unsigned long nr_segs)
+{
+       struct lu_env *env;
+       struct cl_io *io;
+       struct file *file = iocb->ki_filp;
+       struct inode *inode = file->f_mapping->host;
+       ssize_t count = iov_length(iov, nr_segs);
+       ssize_t tot_bytes = 0, result = 0;
+       unsigned long seg = 0;
+       size_t size = MAX_DIO_SIZE;
+       __u16 refcheck;
+       ENTRY;
 
         /* FIXME: io smaller than PAGE_SIZE is broken on ia64 ??? */
-        if ((file_offset & ~CFS_PAGE_MASK) || (count & ~CFS_PAGE_MASK))
+       if ((file_offset & ~PAGE_MASK) || (count & ~PAGE_MASK))
                 RETURN(-EINVAL);
 
-        CDEBUG(D_VFSTRACE, "VFS Op:inode=%lu/%u(%p), size=%lu (max %lu), "
-               "offset=%lld=%llx, pages %lu (max %lu)\n",
-               inode->i_ino, inode->i_generation, inode, count, MAX_DIO_SIZE,
+       CDEBUG(D_VFSTRACE, "VFS Op:inode="DFID"(%p), size=%zd (max %lu), "
+              "offset=%lld=%llx, pages %zd (max %lu)\n",
+              PFID(ll_inode2fid(inode)), inode, count, MAX_DIO_SIZE,
               file_offset, file_offset, count >> PAGE_CACHE_SHIFT,
               MAX_DIO_SIZE >> PAGE_CACHE_SHIFT);
 
         /* Check that all user buffers are aligned as well */
         for (seg = 0; seg < nr_segs; seg++) {
-                if (((unsigned long)iov[seg].iov_base & ~CFS_PAGE_MASK) ||
-                    (iov[seg].iov_len & ~CFS_PAGE_MASK))
+               if (((unsigned long)iov[seg].iov_base & ~PAGE_MASK) ||
+                   (iov[seg].iov_len & ~PAGE_MASK))
                         RETURN(-EINVAL);
         }
 
         env = cl_env_get(&refcheck);
         LASSERT(!IS_ERR(env));
-        io = ccc_env_io(env)->cui_cl.cis_io;
+       io = vvp_env_io(env)->vui_cl.cis_io;
         LASSERT(io != NULL);
 
-       /* 0. Need locking between buffered and direct access. and race with
-        *    size changing by concurrent truncates and writes.
-        * 1. Need inode mutex to operate transient pages.
-        */
-       if (rw == READ)
-               mutex_lock(&inode->i_mutex);
-
-        LASSERT(obj->cob_transient_pages == 0);
         for (seg = 0; seg < nr_segs; seg++) {
-                long iov_left = iov[seg].iov_len;
+               size_t iov_left = iov[seg].iov_len;
                 unsigned long user_addr = (unsigned long)iov[seg].iov_base;
 
                 if (rw == READ) {
@@ -437,7 +534,7 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
                 while (iov_left > 0) {
                         struct page **pages;
                         int page_count, max_pages = 0;
-                        long bytes;
+                       size_t bytes;
 
                         bytes = min(size, iov_left);
                         page_count = ll_get_user_pages(rw, user_addr, bytes,
@@ -445,10 +542,9 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
                         if (likely(page_count > 0)) {
                                 if (unlikely(page_count <  max_pages))
                                        bytes = page_count << PAGE_CACHE_SHIFT;
-                                result = ll_direct_IO_26_seg(env, io, rw, inode,
-                                                             file->f_mapping,
-                                                             bytes, file_offset,
-                                                             pages, page_count);
+                               result = ll_direct_IO_seg(env, io, rw, inode,
+                                                         bytes, file_offset,
+                                                         pages, page_count);
                                 ll_free_user_pages(pages, max_pages, rw==READ);
                         } else if (page_count == 0) {
                                 GOTO(out, result = -EFAULT);
@@ -465,9 +561,9 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
                                    size > (PAGE_CACHE_SIZE / sizeof(*pages)) *
                                           PAGE_CACHE_SIZE) {
                                         size = ((((size / 2) - 1) |
-                                                 ~CFS_PAGE_MASK) + 1) &
-                                                CFS_PAGE_MASK;
-                                        CDEBUG(D_VFSTRACE,"DIO size now %lu\n",
+                                                ~PAGE_CACHE_MASK) + 1) &
+                                               PAGE_CACHE_MASK;
+                                       CDEBUG(D_VFSTRACE, "DIO size now %zu\n",
                                                size);
                                         continue;
                                 }
@@ -482,112 +578,245 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb,
                 }
         }
 out:
-       LASSERT(obj->cob_transient_pages == 0);
-       if (rw == READ)
-               mutex_unlock(&inode->i_mutex);
-
         if (tot_bytes > 0) {
-                if (rw == WRITE) {
-                       struct lov_stripe_md *lsm;
-
-                       lsm = ccc_inode_lsm_get(inode);
-                       LASSERT(lsm != NULL);
-                       lov_stripe_lock(lsm);
-                       obd_adjust_kms(ll_i2dtexp(inode), lsm, file_offset, 0);
-                       lov_stripe_unlock(lsm);
-                       ccc_inode_lsm_put(inode, lsm);
-               }
+               struct vvp_io *vio = vvp_env_io(env);
+
+               /* no commit async for direct IO */
+               vio->u.write.vui_written += tot_bytes;
        }
 
        cl_env_put(env, &refcheck);
-       RETURN(tot_bytes ? : result);
+       RETURN(tot_bytes ? tot_bytes : result);
+}
+#endif /* HAVE_DIRECTIO_ITER || HAVE_IOV_ITER_RW */
+
+/**
+ * Prepare partially written-to page for a write.
+ */
+static int ll_prepare_partial_page(const struct lu_env *env, struct cl_io *io,
+                                  struct cl_page *pg)
+{
+       struct cl_attr *attr   = vvp_env_thread_attr(env);
+       struct cl_object *obj  = io->ci_obj;
+       struct vvp_page *vpg   = cl_object_page_slice(obj, pg);
+       loff_t          offset = cl_offset(obj, vvp_index(vpg));
+       int             result;
+
+       cl_object_attr_lock(obj);
+       result = cl_object_attr_get(env, obj, attr);
+       cl_object_attr_unlock(obj);
+       if (result == 0) {
+               /*
+                * If are writing to a new page, no need to read old data.
+                * The extent locking will have updated the KMS, and for our
+                * purposes here we can treat it like i_size.
+                */
+               if (attr->cat_kms <= offset) {
+                       char *kaddr = ll_kmap_atomic(vpg->vpg_page, KM_USER0);
+
+                       memset(kaddr, 0, cl_page_size(obj));
+                       ll_kunmap_atomic(kaddr, KM_USER0);
+               } else if (vpg->vpg_defer_uptodate)
+                       vpg->vpg_ra_used = 1;
+               else
+                       result = ll_page_sync_io(env, io, pg, CRT_READ);
+       }
+       return result;
 }
 
 static int ll_write_begin(struct file *file, struct address_space *mapping,
-                         loff_t pos, unsigned len, unsigned flags,
-                         struct page **pagep, void **fsdata)
+                         loff_t pos, unsigned len, unsigned flags,
+                         struct page **pagep, void **fsdata)
 {
-        pgoff_t index = pos >> PAGE_CACHE_SHIFT;
-        struct page *page;
-        int rc;
-        unsigned from = pos & (PAGE_CACHE_SIZE - 1);
-        ENTRY;
-
-        page = grab_cache_page_write_begin(mapping, index, flags);
-        if (!page)
-                RETURN(-ENOMEM);
-
-        *pagep = page;
-
-        rc = ll_prepare_write(file, page, from, from + len);
-        if (rc) {
-                unlock_page(page);
-                page_cache_release(page);
-        }
-        RETURN(rc);
+       struct ll_cl_context *lcc;
+       const struct lu_env  *env;
+       struct cl_io   *io;
+       struct cl_page *page;
+
+       struct cl_object *clob = ll_i2info(mapping->host)->lli_clob;
+       pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+       struct page *vmpage = NULL;
+       unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+       unsigned to = from + len;
+       int result = 0;
+       ENTRY;
+
+       CDEBUG(D_VFSTRACE, "Writing %lu of %d to %d bytes\n", index, from, len);
+
+       lcc = ll_cl_find(file);
+       if (lcc == NULL) {
+               io = NULL;
+               GOTO(out, result = -EIO);
+       }
+
+       env = lcc->lcc_env;
+       io  = lcc->lcc_io;
+
+       /* To avoid deadlock, try to lock page first. */
+       vmpage = grab_cache_page_nowait(mapping, index);
+
+       if (unlikely(vmpage == NULL ||
+                    PageDirty(vmpage) || PageWriteback(vmpage))) {
+               struct vvp_io *vio = vvp_env_io(env);
+               struct cl_page_list *plist = &vio->u.write.vui_queue;
+
+                /* if the page is already in dirty cache, we have to commit
+                * the pages right now; otherwise, it may cause deadlock
+                * because it holds page lock of a dirty page and request for
+                * more grants. It's okay for the dirty page to be the first
+                * one in commit page list, though. */
+               if (vmpage != NULL && plist->pl_nr > 0) {
+                       unlock_page(vmpage);
+                       page_cache_release(vmpage);
+                       vmpage = NULL;
+               }
+
+               /* commit pages and then wait for page lock */
+               result = vvp_io_write_commit(env, io);
+               if (result < 0)
+                       GOTO(out, result);
+
+               if (vmpage == NULL) {
+                       vmpage = grab_cache_page_write_begin(mapping, index,
+                                                            flags);
+                       if (vmpage == NULL)
+                               GOTO(out, result = -ENOMEM);
+               }
+       }
+
+       page = cl_page_find(env, clob, vmpage->index, vmpage, CPT_CACHEABLE);
+       if (IS_ERR(page))
+               GOTO(out, result = PTR_ERR(page));
+
+       lcc->lcc_page = page;
+       lu_ref_add(&page->cp_reference, "cl_io", io);
+
+       cl_page_assume(env, io, page);
+       if (!PageUptodate(vmpage)) {
+               /*
+                * We're completely overwriting an existing page,
+                * so _don't_ set it up to date until commit_write
+                */
+               if (from == 0 && to == PAGE_SIZE) {
+                       CL_PAGE_HEADER(D_PAGE, env, page, "full page write\n");
+                       POISON_PAGE(vmpage, 0x11);
+               } else {
+                       /* TODO: can be optimized at OSC layer to check if it
+                        * is a lockless IO. In that case, it's not necessary
+                        * to read the data. */
+                       result = ll_prepare_partial_page(env, io, page);
+                       if (result == 0)
+                               SetPageUptodate(vmpage);
+               }
+       }
+       if (result < 0)
+               cl_page_unassume(env, io, page);
+       EXIT;
+out:
+       if (result < 0) {
+               if (vmpage != NULL) {
+                       unlock_page(vmpage);
+                       page_cache_release(vmpage);
+               }
+               if (io)
+                       io->ci_result = result;
+       } else {
+               *pagep = vmpage;
+               *fsdata = lcc;
+       }
+       RETURN(result);
 }
 
 static int ll_write_end(struct file *file, struct address_space *mapping,
-                        loff_t pos, unsigned len, unsigned copied,
-                        struct page *page, void *fsdata)
+                       loff_t pos, unsigned len, unsigned copied,
+                       struct page *vmpage, void *fsdata)
 {
-        unsigned from = pos & (PAGE_CACHE_SIZE - 1);
-        int rc;
-
-        rc = ll_commit_write(file, page, from, from + copied);
-        unlock_page(page);
-        page_cache_release(page);
+       struct ll_cl_context *lcc = fsdata;
+       const struct lu_env *env;
+       struct cl_io *io;
+       struct vvp_io *vio;
+       struct cl_page *page;
+       unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+       bool unplug = false;
+       int result = 0;
+       ENTRY;
+
+       page_cache_release(vmpage);
+
+       LASSERT(lcc != NULL);
+       env  = lcc->lcc_env;
+       page = lcc->lcc_page;
+       io   = lcc->lcc_io;
+       vio  = vvp_env_io(env);
+
+       LASSERT(cl_page_is_owned(page, io));
+       if (copied > 0) {
+               struct cl_page_list *plist = &vio->u.write.vui_queue;
+
+               lcc->lcc_page = NULL; /* page will be queued */
+
+               /* Add it into write queue */
+               cl_page_list_add(plist, page);
+               if (plist->pl_nr == 1) /* first page */
+                       vio->u.write.vui_from = from;
+               else
+                       LASSERT(from == 0);
+               vio->u.write.vui_to = from + copied;
+
+               /* To address the deadlock in balance_dirty_pages() where
+                * this dirty page may be written back in the same thread. */
+               if (PageDirty(vmpage))
+                       unplug = true;
+
+               /* We may have one full RPC, commit it soon */
+               if (plist->pl_nr >= PTLRPC_MAX_BRW_PAGES)
+                       unplug = true;
+
+               CL_PAGE_DEBUG(D_VFSTRACE, env, page,
+                             "queued page: %d.\n", plist->pl_nr);
+       } else {
+               cl_page_disown(env, io, page);
+
+               lcc->lcc_page = NULL;
+               lu_ref_del(&page->cp_reference, "cl_io", io);
+               cl_page_put(env, page);
+
+               /* page list is not contiguous now, commit it now */
+               unplug = true;
+       }
+       if (unplug ||
+           file->f_flags & O_SYNC || IS_SYNC(file->f_path.dentry->d_inode))
+               result = vvp_io_write_commit(env, io);
 
-        return rc ?: copied;
+       if (result < 0)
+               io->ci_result = result;
+       RETURN(result >= 0 ? copied : result);
 }
 
 #ifdef CONFIG_MIGRATION
-int ll_migratepage(struct address_space *mapping,
-               struct page *newpage, struct page *page
+static int ll_migratepage(struct address_space *mapping,
+                         struct page *newpage, struct page *page
 #ifdef HAVE_MIGRATEPAGE_4ARGS
-               , enum migrate_mode mode
+                         , enum migrate_mode mode
 #endif
-               )
+       )
 {
         /* Always fail page migration until we have a proper implementation */
         return -EIO;
 }
 #endif
 
-#ifndef MS_HAS_NEW_AOPS
-struct address_space_operations ll_aops = {
-        .readpage       = ll_readpage,
-//        .readpages      = ll_readpages,
-        .direct_IO      = ll_direct_IO_26,
-        .writepage      = ll_writepage,
-       .writepages     = ll_writepages,
-        .set_page_dirty = ll_set_page_dirty,
-        .write_begin    = ll_write_begin,
-        .write_end      = ll_write_end,
-        .invalidatepage = ll_invalidatepage,
-        .releasepage    = (void *)ll_releasepage,
-#ifdef CONFIG_MIGRATION
-        .migratepage    = ll_migratepage,
-#endif
-        .bmap           = NULL
-};
-#else
-struct address_space_operations_ext ll_aops = {
-        .orig_aops.readpage       = ll_readpage,
-//        .orig_aops.readpages      = ll_readpages,
-        .orig_aops.direct_IO      = ll_direct_IO_26,
-        .orig_aops.writepage      = ll_writepage,
-       .orig_aops.writepages     = ll_writepages,
-        .orig_aops.set_page_dirty = ll_set_page_dirty,
-        .orig_aops.prepare_write  = ll_prepare_write,
-        .orig_aops.commit_write   = ll_commit_write,
-        .orig_aops.invalidatepage = ll_invalidatepage,
-        .orig_aops.releasepage    = ll_releasepage,
+const struct address_space_operations ll_aops = {
+       .readpage       = ll_readpage,
+       .direct_IO      = ll_direct_IO,
+       .writepage      = ll_writepage,
+       .writepages     = ll_writepages,
+       .set_page_dirty = __set_page_dirty_nobuffers,
+       .write_begin    = ll_write_begin,
+       .write_end      = ll_write_end,
+       .invalidatepage = ll_invalidatepage,
+       .releasepage    = (void *)ll_releasepage,
 #ifdef CONFIG_MIGRATION
-        .orig_aops.migratepage    = ll_migratepage,
+       .migratepage    = ll_migratepage,
 #endif
-        .orig_aops.bmap           = NULL,
-        .write_begin    = ll_write_begin,
-        .write_end      = ll_write_end
 };
-#endif