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ocfs2: fix sparse file & data ordering issue in direct io
[uclinux-h8/linux.git] / fs / ocfs2 / aops.c
index c29d066..578ce22 100644 (file)
@@ -499,158 +499,6 @@ bail:
        return status;
 }
 
-/*
- * TODO: Make this into a generic get_blocks function.
- *
- * From do_direct_io in direct-io.c:
- *  "So what we do is to permit the ->get_blocks function to populate
- *   bh.b_size with the size of IO which is permitted at this offset and
- *   this i_blkbits."
- *
- * This function is called directly from get_more_blocks in direct-io.c.
- *
- * called like this: dio->get_blocks(dio->inode, fs_startblk,
- *                                     fs_count, map_bh, dio->rw == WRITE);
- */
-static int ocfs2_direct_IO_get_blocks(struct inode *inode, sector_t iblock,
-                                    struct buffer_head *bh_result, int create)
-{
-       int ret;
-       u32 cpos = 0;
-       int alloc_locked = 0;
-       u64 p_blkno, inode_blocks, contig_blocks;
-       unsigned int ext_flags;
-       unsigned char blocksize_bits = inode->i_sb->s_blocksize_bits;
-       unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
-       unsigned long len = bh_result->b_size;
-       unsigned int clusters_to_alloc = 0, contig_clusters = 0;
-
-       cpos = ocfs2_blocks_to_clusters(inode->i_sb, iblock);
-
-       /* This function won't even be called if the request isn't all
-        * nicely aligned and of the right size, so there's no need
-        * for us to check any of that. */
-
-       inode_blocks = ocfs2_blocks_for_bytes(inode->i_sb, i_size_read(inode));
-
-       down_read(&OCFS2_I(inode)->ip_alloc_sem);
-
-       /* This figures out the size of the next contiguous block, and
-        * our logical offset */
-       ret = ocfs2_extent_map_get_blocks(inode, iblock, &p_blkno,
-                                         &contig_blocks, &ext_flags);
-       up_read(&OCFS2_I(inode)->ip_alloc_sem);
-
-       if (ret) {
-               mlog(ML_ERROR, "get_blocks() failed iblock=%llu\n",
-                    (unsigned long long)iblock);
-               ret = -EIO;
-               goto bail;
-       }
-
-       /* We should already CoW the refcounted extent in case of create. */
-       BUG_ON(create && (ext_flags & OCFS2_EXT_REFCOUNTED));
-
-       /* allocate blocks if no p_blkno is found, and create == 1 */
-       if (!p_blkno && create) {
-               ret = ocfs2_inode_lock(inode, NULL, 1);
-               if (ret < 0) {
-                       mlog_errno(ret);
-                       goto bail;
-               }
-
-               alloc_locked = 1;
-
-               down_write(&OCFS2_I(inode)->ip_alloc_sem);
-
-               /* fill hole, allocate blocks can't be larger than the size
-                * of the hole */
-               clusters_to_alloc = ocfs2_clusters_for_bytes(inode->i_sb, len);
-               contig_clusters = ocfs2_clusters_for_blocks(inode->i_sb,
-                               contig_blocks);
-               if (clusters_to_alloc > contig_clusters)
-                       clusters_to_alloc = contig_clusters;
-
-               /* allocate extent and insert them into the extent tree */
-               ret = ocfs2_extend_allocation(inode, cpos,
-                               clusters_to_alloc, 0);
-               if (ret < 0) {
-                       up_write(&OCFS2_I(inode)->ip_alloc_sem);
-                       mlog_errno(ret);
-                       goto bail;
-               }
-
-               ret = ocfs2_extent_map_get_blocks(inode, iblock, &p_blkno,
-                               &contig_blocks, &ext_flags);
-               if (ret < 0) {
-                       up_write(&OCFS2_I(inode)->ip_alloc_sem);
-                       mlog(ML_ERROR, "get_blocks() failed iblock=%llu\n",
-                                       (unsigned long long)iblock);
-                       ret = -EIO;
-                       goto bail;
-               }
-               set_buffer_new(bh_result);
-               up_write(&OCFS2_I(inode)->ip_alloc_sem);
-       }
-
-       /*
-        * get_more_blocks() expects us to describe a hole by clearing
-        * the mapped bit on bh_result().
-        *
-        * Consider an unwritten extent as a hole.
-        */
-       if (p_blkno && !(ext_flags & OCFS2_EXT_UNWRITTEN))
-               map_bh(bh_result, inode->i_sb, p_blkno);
-       else
-               clear_buffer_mapped(bh_result);
-
-       /* make sure we don't map more than max_blocks blocks here as
-          that's all the kernel will handle at this point. */
-       if (max_blocks < contig_blocks)
-               contig_blocks = max_blocks;
-       bh_result->b_size = contig_blocks << blocksize_bits;
-bail:
-       if (alloc_locked)
-               ocfs2_inode_unlock(inode, 1);
-       return ret;
-}
-
-/*
- * ocfs2_dio_end_io is called by the dio core when a dio is finished.  We're
- * particularly interested in the aio/dio case.  We use the rw_lock DLM lock
- * to protect io on one node from truncation on another.
- */
-static int ocfs2_dio_end_io(struct kiocb *iocb,
-                            loff_t offset,
-                            ssize_t bytes,
-                            void *private)
-{
-       struct inode *inode = file_inode(iocb->ki_filp);
-       int level;
-
-       if (bytes <= 0)
-               return 0;
-
-       /* this io's submitter should not have unlocked this before we could */
-       BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
-
-       if (ocfs2_iocb_is_unaligned_aio(iocb)) {
-               ocfs2_iocb_clear_unaligned_aio(iocb);
-
-               mutex_unlock(&OCFS2_I(inode)->ip_unaligned_aio);
-       }
-
-       /* Let rw unlock to be done later to protect append direct io write */
-       if (offset + bytes <= i_size_read(inode)) {
-               ocfs2_iocb_clear_rw_locked(iocb);
-
-               level = ocfs2_iocb_rw_locked_level(iocb);
-               ocfs2_rw_unlock(inode, level);
-       }
-
-       return 0;
-}
-
 static int ocfs2_releasepage(struct page *page, gfp_t wait)
 {
        if (!page_has_buffers(page))
@@ -658,363 +506,6 @@ static int ocfs2_releasepage(struct page *page, gfp_t wait)
        return try_to_free_buffers(page);
 }
 
-static int ocfs2_is_overwrite(struct ocfs2_super *osb,
-               struct inode *inode, loff_t offset)
-{
-       int ret = 0;
-       u32 v_cpos = 0;
-       u32 p_cpos = 0;
-       unsigned int num_clusters = 0;
-       unsigned int ext_flags = 0;
-
-       v_cpos = ocfs2_bytes_to_clusters(osb->sb, offset);
-       ret = ocfs2_get_clusters(inode, v_cpos, &p_cpos,
-                       &num_clusters, &ext_flags);
-       if (ret < 0) {
-               mlog_errno(ret);
-               return ret;
-       }
-
-       if (p_cpos && !(ext_flags & OCFS2_EXT_UNWRITTEN))
-               return 1;
-
-       return 0;
-}
-
-static int ocfs2_direct_IO_zero_extend(struct ocfs2_super *osb,
-               struct inode *inode, loff_t offset,
-               u64 zero_len, int cluster_align)
-{
-       u32 p_cpos = 0;
-       u32 v_cpos = ocfs2_bytes_to_clusters(osb->sb, i_size_read(inode));
-       unsigned int num_clusters = 0;
-       unsigned int ext_flags = 0;
-       int ret = 0;
-
-       if (offset <= i_size_read(inode) || cluster_align)
-               return 0;
-
-       ret = ocfs2_get_clusters(inode, v_cpos, &p_cpos, &num_clusters,
-                       &ext_flags);
-       if (ret < 0) {
-               mlog_errno(ret);
-               return ret;
-       }
-
-       if (p_cpos && !(ext_flags & OCFS2_EXT_UNWRITTEN)) {
-               u64 s = i_size_read(inode);
-               sector_t sector = ((u64)p_cpos << (osb->s_clustersize_bits - 9)) +
-                       (do_div(s, osb->s_clustersize) >> 9);
-
-               ret = blkdev_issue_zeroout(osb->sb->s_bdev, sector,
-                               zero_len >> 9, GFP_NOFS, false);
-               if (ret < 0)
-                       mlog_errno(ret);
-       }
-
-       return ret;
-}
-
-static int ocfs2_direct_IO_extend_no_holes(struct ocfs2_super *osb,
-               struct inode *inode, loff_t offset)
-{
-       u64 zero_start, zero_len, total_zero_len;
-       u32 p_cpos = 0, clusters_to_add;
-       u32 v_cpos = ocfs2_bytes_to_clusters(osb->sb, i_size_read(inode));
-       unsigned int num_clusters = 0;
-       unsigned int ext_flags = 0;
-       u32 size_div, offset_div;
-       int ret = 0;
-
-       {
-               u64 o = offset;
-               u64 s = i_size_read(inode);
-
-               offset_div = do_div(o, osb->s_clustersize);
-               size_div = do_div(s, osb->s_clustersize);
-       }
-
-       if (offset <= i_size_read(inode))
-               return 0;
-
-       clusters_to_add = ocfs2_bytes_to_clusters(inode->i_sb, offset) -
-               ocfs2_bytes_to_clusters(inode->i_sb, i_size_read(inode));
-       total_zero_len = offset - i_size_read(inode);
-       if (clusters_to_add)
-               total_zero_len -= offset_div;
-
-       /* Allocate clusters to fill out holes, and this is only needed
-        * when we add more than one clusters. Otherwise the cluster will
-        * be allocated during direct IO */
-       if (clusters_to_add > 1) {
-               ret = ocfs2_extend_allocation(inode,
-                               OCFS2_I(inode)->ip_clusters,
-                               clusters_to_add - 1, 0);
-               if (ret) {
-                       mlog_errno(ret);
-                       goto out;
-               }
-       }
-
-       while (total_zero_len) {
-               ret = ocfs2_get_clusters(inode, v_cpos, &p_cpos, &num_clusters,
-                               &ext_flags);
-               if (ret < 0) {
-                       mlog_errno(ret);
-                       goto out;
-               }
-
-               zero_start = ocfs2_clusters_to_bytes(osb->sb, p_cpos) +
-                       size_div;
-               zero_len = ocfs2_clusters_to_bytes(osb->sb, num_clusters) -
-                       size_div;
-               zero_len = min(total_zero_len, zero_len);
-
-               if (p_cpos && !(ext_flags & OCFS2_EXT_UNWRITTEN)) {
-                       ret = blkdev_issue_zeroout(osb->sb->s_bdev,
-                                       zero_start >> 9, zero_len >> 9,
-                                       GFP_NOFS, false);
-                       if (ret < 0) {
-                               mlog_errno(ret);
-                               goto out;
-                       }
-               }
-
-               total_zero_len -= zero_len;
-               v_cpos += ocfs2_bytes_to_clusters(osb->sb, zero_len + size_div);
-
-               /* Only at first iteration can be cluster not aligned.
-                * So set size_div to 0 for the rest */
-               size_div = 0;
-       }
-
-out:
-       return ret;
-}
-
-static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb,
-               struct iov_iter *iter,
-               loff_t offset)
-{
-       ssize_t ret = 0;
-       ssize_t written = 0;
-       bool orphaned = false;
-       int is_overwrite = 0;
-       struct file *file = iocb->ki_filp;
-       struct inode *inode = file_inode(file)->i_mapping->host;
-       struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
-       struct buffer_head *di_bh = NULL;
-       size_t count = iter->count;
-       journal_t *journal = osb->journal->j_journal;
-       u64 zero_len_head, zero_len_tail;
-       int cluster_align_head, cluster_align_tail;
-       loff_t final_size = offset + count;
-       int append_write = offset >= i_size_read(inode) ? 1 : 0;
-       unsigned int num_clusters = 0;
-       unsigned int ext_flags = 0;
-
-       {
-               u64 o = offset;
-               u64 s = i_size_read(inode);
-
-               zero_len_head = do_div(o, 1 << osb->s_clustersize_bits);
-               cluster_align_head = !zero_len_head;
-
-               zero_len_tail = osb->s_clustersize -
-                       do_div(s, osb->s_clustersize);
-               if ((offset - i_size_read(inode)) < zero_len_tail)
-                       zero_len_tail = offset - i_size_read(inode);
-               cluster_align_tail = !zero_len_tail;
-       }
-
-       /*
-        * when final_size > inode->i_size, inode->i_size will be
-        * updated after direct write, so add the inode to orphan
-        * dir first.
-        */
-       if (final_size > i_size_read(inode)) {
-               ret = ocfs2_add_inode_to_orphan(osb, inode);
-               if (ret < 0) {
-                       mlog_errno(ret);
-                       goto out;
-               }
-               orphaned = true;
-       }
-
-       if (append_write) {
-               ret = ocfs2_inode_lock(inode, NULL, 1);
-               if (ret < 0) {
-                       mlog_errno(ret);
-                       goto clean_orphan;
-               }
-
-               /* zeroing out the previously allocated cluster tail
-                * that but not zeroed */
-               if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb))) {
-                       down_read(&OCFS2_I(inode)->ip_alloc_sem);
-                       ret = ocfs2_direct_IO_zero_extend(osb, inode, offset,
-                                       zero_len_tail, cluster_align_tail);
-                       up_read(&OCFS2_I(inode)->ip_alloc_sem);
-               } else {
-                       down_write(&OCFS2_I(inode)->ip_alloc_sem);
-                       ret = ocfs2_direct_IO_extend_no_holes(osb, inode,
-                                       offset);
-                       up_write(&OCFS2_I(inode)->ip_alloc_sem);
-               }
-               if (ret < 0) {
-                       mlog_errno(ret);
-                       ocfs2_inode_unlock(inode, 1);
-                       goto clean_orphan;
-               }
-
-               is_overwrite = ocfs2_is_overwrite(osb, inode, offset);
-               if (is_overwrite < 0) {
-                       mlog_errno(is_overwrite);
-                       ret = is_overwrite;
-                       ocfs2_inode_unlock(inode, 1);
-                       goto clean_orphan;
-               }
-
-               ocfs2_inode_unlock(inode, 1);
-       }
-
-       written = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
-                                      offset, ocfs2_direct_IO_get_blocks,
-                                      ocfs2_dio_end_io, NULL, 0);
-       /* overwrite aio may return -EIOCBQUEUED, and it is not an error */
-       if ((written < 0) && (written != -EIOCBQUEUED)) {
-               loff_t i_size = i_size_read(inode);
-
-               if (offset + count > i_size) {
-                       ret = ocfs2_inode_lock(inode, &di_bh, 1);
-                       if (ret < 0) {
-                               mlog_errno(ret);
-                               goto clean_orphan;
-                       }
-
-                       if (i_size == i_size_read(inode)) {
-                               ret = ocfs2_truncate_file(inode, di_bh,
-                                               i_size);
-                               if (ret < 0) {
-                                       if (ret != -ENOSPC)
-                                               mlog_errno(ret);
-
-                                       ocfs2_inode_unlock(inode, 1);
-                                       brelse(di_bh);
-                                       di_bh = NULL;
-                                       goto clean_orphan;
-                               }
-                       }
-
-                       ocfs2_inode_unlock(inode, 1);
-                       brelse(di_bh);
-                       di_bh = NULL;
-
-                       ret = jbd2_journal_force_commit(journal);
-                       if (ret < 0)
-                               mlog_errno(ret);
-               }
-       } else if (written > 0 && append_write && !is_overwrite &&
-                       !cluster_align_head) {
-               /* zeroing out the allocated cluster head */
-               u32 p_cpos = 0;
-               u32 v_cpos = ocfs2_bytes_to_clusters(osb->sb, offset);
-
-               ret = ocfs2_inode_lock(inode, NULL, 0);
-               if (ret < 0) {
-                       mlog_errno(ret);
-                       goto clean_orphan;
-               }
-
-               ret = ocfs2_get_clusters(inode, v_cpos, &p_cpos,
-                               &num_clusters, &ext_flags);
-               if (ret < 0) {
-                       mlog_errno(ret);
-                       ocfs2_inode_unlock(inode, 0);
-                       goto clean_orphan;
-               }
-
-               BUG_ON(!p_cpos || (ext_flags & OCFS2_EXT_UNWRITTEN));
-
-               ret = blkdev_issue_zeroout(osb->sb->s_bdev,
-                               (u64)p_cpos << (osb->s_clustersize_bits - 9),
-                               zero_len_head >> 9, GFP_NOFS, false);
-               if (ret < 0)
-                       mlog_errno(ret);
-
-               ocfs2_inode_unlock(inode, 0);
-       }
-
-clean_orphan:
-       if (orphaned) {
-               int tmp_ret;
-               int update_isize = written > 0 ? 1 : 0;
-               loff_t end = update_isize ? offset + written : 0;
-
-               tmp_ret = ocfs2_inode_lock(inode, &di_bh, 1);
-               if (tmp_ret < 0) {
-                       ret = tmp_ret;
-                       mlog_errno(ret);
-                       goto out;
-               }
-
-               tmp_ret = ocfs2_del_inode_from_orphan(osb, inode, di_bh,
-                               update_isize, end);
-               if (tmp_ret < 0) {
-                       ocfs2_inode_unlock(inode, 1);
-                       ret = tmp_ret;
-                       mlog_errno(ret);
-                       brelse(di_bh);
-                       goto out;
-               }
-
-               ocfs2_inode_unlock(inode, 1);
-               brelse(di_bh);
-
-               tmp_ret = jbd2_journal_force_commit(journal);
-               if (tmp_ret < 0) {
-                       ret = tmp_ret;
-                       mlog_errno(tmp_ret);
-               }
-       }
-
-out:
-       if (ret >= 0)
-               ret = written;
-       return ret;
-}
-
-static ssize_t ocfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-                              loff_t offset)
-{
-       struct file *file = iocb->ki_filp;
-       struct inode *inode = file_inode(file)->i_mapping->host;
-       struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
-       int full_coherency = !(osb->s_mount_opt &
-                       OCFS2_MOUNT_COHERENCY_BUFFERED);
-
-       /*
-        * Fallback to buffered I/O if we see an inode without
-        * extents.
-        */
-       if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
-               return 0;
-
-       /* Fallback to buffered I/O if we are appending and
-        * concurrent O_DIRECT writes are allowed.
-        */
-       if (i_size_read(inode) <= offset && !full_coherency)
-               return 0;
-
-       if (iov_iter_rw(iter) == READ)
-               return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev,
-                                           iter, offset,
-                                           ocfs2_direct_IO_get_blocks,
-                                           ocfs2_dio_end_io, NULL, 0);
-       else
-               return ocfs2_direct_IO_write(iocb, iter, offset);
-}
-
 static void ocfs2_figure_cluster_boundaries(struct ocfs2_super *osb,
                                            u32 cpos,
                                            unsigned int *start,
@@ -1326,14 +817,14 @@ static void ocfs2_free_unwritten_list(struct inode *inode,
                                 struct list_head *head)
 {
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
-       struct ocfs2_unwritten_extent *dz = NULL, *tmp = NULL;
+       struct ocfs2_unwritten_extent *ue = NULL, *tmp = NULL;
 
-       list_for_each_entry_safe(dz, tmp, head, ue_node) {
-               list_del(&dz->ue_node);
+       list_for_each_entry_safe(ue, tmp, head, ue_node) {
+               list_del(&ue->ue_node);
                spin_lock(&oi->ip_lock);
-               list_del(&dz->ue_ip_node);
+               list_del(&ue->ue_ip_node);
                spin_unlock(&oi->ip_lock);
-               kfree(dz);
+               kfree(ue);
        }
 }
 
@@ -1834,7 +1325,7 @@ static int ocfs2_unwritten_check(struct inode *inode,
                                 struct ocfs2_write_cluster_desc *desc)
 {
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
-       struct ocfs2_unwritten_extent *dz = NULL, *new = NULL;
+       struct ocfs2_unwritten_extent *ue = NULL, *new = NULL;
        int ret = 0;
 
        if (!desc->c_needs_zero)
@@ -1845,8 +1336,8 @@ retry:
        /* Needs not to zero no metter buffer or direct. The one who is zero
         * the cluster is doing zero. And he will clear unwritten after all
         * cluster io finished. */
-       list_for_each_entry(dz, &oi->ip_unwritten_list, ue_ip_node) {
-               if (desc->c_cpos == dz->ue_cpos) {
+       list_for_each_entry(ue, &oi->ip_unwritten_list, ue_ip_node) {
+               if (desc->c_cpos == ue->ue_cpos) {
                        BUG_ON(desc->c_new);
                        desc->c_needs_zero = 0;
                        desc->c_clear_unwritten = 0;
@@ -2608,6 +2099,344 @@ static int ocfs2_write_end(struct file *file, struct address_space *mapping,
        return ret;
 }
 
+struct ocfs2_dio_write_ctxt {
+       struct list_head        dw_zero_list;
+       unsigned                dw_zero_count;
+       int                     dw_orphaned;
+       pid_t                   dw_writer_pid;
+};
+
+static struct ocfs2_dio_write_ctxt *
+ocfs2_dio_alloc_write_ctx(struct buffer_head *bh, int *alloc)
+{
+       struct ocfs2_dio_write_ctxt *dwc = NULL;
+
+       if (bh->b_private)
+               return bh->b_private;
+
+       dwc = kmalloc(sizeof(struct ocfs2_dio_write_ctxt), GFP_NOFS);
+       if (dwc == NULL)
+               return NULL;
+       INIT_LIST_HEAD(&dwc->dw_zero_list);
+       dwc->dw_zero_count = 0;
+       dwc->dw_orphaned = 0;
+       dwc->dw_writer_pid = task_pid_nr(current);
+       bh->b_private = dwc;
+       *alloc = 1;
+
+       return dwc;
+}
+
+static void ocfs2_dio_free_write_ctx(struct inode *inode,
+                                    struct ocfs2_dio_write_ctxt *dwc)
+{
+       ocfs2_free_unwritten_list(inode, &dwc->dw_zero_list);
+       kfree(dwc);
+}
+
+/*
+ * TODO: Make this into a generic get_blocks function.
+ *
+ * From do_direct_io in direct-io.c:
+ *  "So what we do is to permit the ->get_blocks function to populate
+ *   bh.b_size with the size of IO which is permitted at this offset and
+ *   this i_blkbits."
+ *
+ * This function is called directly from get_more_blocks in direct-io.c.
+ *
+ * called like this: dio->get_blocks(dio->inode, fs_startblk,
+ *                                     fs_count, map_bh, dio->rw == WRITE);
+ */
+static int ocfs2_dio_get_block(struct inode *inode, sector_t iblock,
+                              struct buffer_head *bh_result, int create)
+{
+       struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+       struct ocfs2_write_ctxt *wc;
+       struct ocfs2_write_cluster_desc *desc = NULL;
+       struct ocfs2_dio_write_ctxt *dwc = NULL;
+       struct buffer_head *di_bh = NULL;
+       u64 p_blkno;
+       loff_t pos = iblock << inode->i_sb->s_blocksize_bits;
+       unsigned len, total_len = bh_result->b_size;
+       int ret = 0, first_get_block = 0;
+
+       len = osb->s_clustersize - (pos & (osb->s_clustersize - 1));
+       len = min(total_len, len);
+
+       mlog(0, "get block of %lu at %llu:%u req %u\n",
+                       inode->i_ino, pos, len, total_len);
+
+       /* This is the fast path for re-write. */
+       ret = ocfs2_get_block(inode, iblock, bh_result, create);
+
+       if (buffer_mapped(bh_result) &&
+           !buffer_new(bh_result) &&
+           ret == 0)
+               goto out;
+
+       /* Clear state set by ocfs2_get_block. */
+       bh_result->b_state = 0;
+
+       dwc = ocfs2_dio_alloc_write_ctx(bh_result, &first_get_block);
+       if (unlikely(dwc == NULL)) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto out;
+       }
+
+       if (ocfs2_clusters_for_bytes(inode->i_sb, pos + total_len) >
+           ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode)) &&
+           !dwc->dw_orphaned) {
+               /*
+                * when we are going to alloc extents beyond file size, add the
+                * inode to orphan dir, so we can recall those spaces when
+                * system crashed during write.
+                */
+               ret = ocfs2_add_inode_to_orphan(osb, inode);
+               if (ret < 0) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+               dwc->dw_orphaned = 1;
+       }
+
+       ret = ocfs2_inode_lock(inode, &di_bh, 1);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       if (first_get_block) {
+               if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
+                       ret = ocfs2_zero_tail(inode, di_bh, pos);
+               else
+                       ret = ocfs2_expand_nonsparse_inode(inode, di_bh, pos,
+                                                          total_len, NULL);
+               if (ret < 0) {
+                       mlog_errno(ret);
+                       goto unlock;
+               }
+       }
+
+       ret = ocfs2_write_begin_nolock(inode->i_mapping, pos, len,
+                                      OCFS2_WRITE_DIRECT, NULL,
+                                      (void **)&wc, di_bh, NULL);
+       if (ret) {
+               mlog_errno(ret);
+               goto unlock;
+       }
+
+       desc = &wc->w_desc[0];
+
+       p_blkno = ocfs2_clusters_to_blocks(inode->i_sb, desc->c_phys);
+       BUG_ON(p_blkno == 0);
+       p_blkno += iblock & (u64)(ocfs2_clusters_to_blocks(inode->i_sb, 1) - 1);
+
+       map_bh(bh_result, inode->i_sb, p_blkno);
+       bh_result->b_size = len;
+       if (desc->c_needs_zero)
+               set_buffer_new(bh_result);
+
+       /* May sleep in end_io. It should not happen in a irq context. So defer
+        * it to dio work queue. */
+       set_buffer_defer_completion(bh_result);
+
+       if (!list_empty(&wc->w_unwritten_list)) {
+               struct ocfs2_unwritten_extent *ue = NULL;
+
+               ue = list_first_entry(&wc->w_unwritten_list,
+                                     struct ocfs2_unwritten_extent,
+                                     ue_node);
+               BUG_ON(ue->ue_cpos != desc->c_cpos);
+               /* The physical address may be 0, fill it. */
+               ue->ue_phys = desc->c_phys;
+
+               list_splice_tail_init(&wc->w_unwritten_list, &dwc->dw_zero_list);
+               dwc->dw_zero_count++;
+       }
+
+       ret = ocfs2_write_end_nolock(inode->i_mapping, pos, len, len, NULL, wc);
+       BUG_ON(ret != len);
+       ret = 0;
+unlock:
+       ocfs2_inode_unlock(inode, 1);
+       brelse(di_bh);
+out:
+       if (ret < 0)
+               ret = -EIO;
+       return ret;
+}
+
+static void ocfs2_dio_end_io_write(struct inode *inode,
+                                  struct ocfs2_dio_write_ctxt *dwc,
+                                  loff_t offset,
+                                  ssize_t bytes)
+{
+       struct ocfs2_cached_dealloc_ctxt dealloc;
+       struct ocfs2_extent_tree et;
+       struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+       struct ocfs2_unwritten_extent *ue = NULL;
+       struct buffer_head *di_bh = NULL;
+       struct ocfs2_dinode *di;
+       struct ocfs2_alloc_context *data_ac = NULL;
+       struct ocfs2_alloc_context *meta_ac = NULL;
+       handle_t *handle = NULL;
+       loff_t end = offset + bytes;
+       int ret = 0, credits = 0, locked = 0;
+
+       ocfs2_init_dealloc_ctxt(&dealloc);
+
+       /* We do clear unwritten, delete orphan, change i_size here. If neither
+        * of these happen, we can skip all this. */
+       if (list_empty(&dwc->dw_zero_list) &&
+           end <= i_size_read(inode) &&
+           !dwc->dw_orphaned)
+               goto out;
+
+       ret = ocfs2_inode_lock(inode, &di_bh, 1);
+       if (ret < 0) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       /* ocfs2_file_write_iter will get i_mutex, so we need not lock if we
+        * are in that context. */
+       if (dwc->dw_writer_pid != task_pid_nr(current)) {
+               mutex_lock(&inode->i_mutex);
+               locked = 1;
+       }
+
+       /* Delete orphan before acquire i_mutex. */
+       if (dwc->dw_orphaned) {
+               BUG_ON(dwc->dw_writer_pid != task_pid_nr(current));
+
+               end = end > i_size_read(inode) ? end : 0;
+
+               ret = ocfs2_del_inode_from_orphan(osb, inode, di_bh,
+                               !!end, end);
+               if (ret < 0)
+                       mlog_errno(ret);
+       }
+
+       di = (struct ocfs2_dinode *)di_bh;
+
+       ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), di_bh);
+
+       ret = ocfs2_lock_allocators(inode, &et, 0, dwc->dw_zero_count*2,
+                                   &data_ac, &meta_ac);
+
+       credits = ocfs2_calc_extend_credits(inode->i_sb, &di->id2.i_list);
+
+       handle = ocfs2_start_trans(osb, credits);
+       if (IS_ERR(handle)) {
+               ret = PTR_ERR(handle);
+               mlog_errno(ret);
+               goto unlock;
+       }
+       ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
+                                     OCFS2_JOURNAL_ACCESS_WRITE);
+       if (ret) {
+               mlog_errno(ret);
+               goto commit;
+       }
+
+       list_for_each_entry(ue, &dwc->dw_zero_list, ue_node) {
+               ret = ocfs2_mark_extent_written(inode, &et, handle,
+                                               ue->ue_cpos, 1,
+                                               ue->ue_phys,
+                                               meta_ac, &dealloc);
+               if (ret < 0) {
+                       mlog_errno(ret);
+                       break;
+               }
+       }
+
+       if (end > i_size_read(inode)) {
+               ret = ocfs2_set_inode_size(handle, inode, di_bh, end);
+               if (ret < 0)
+                       mlog_errno(ret);
+       }
+commit:
+       ocfs2_commit_trans(osb, handle);
+unlock:
+       ocfs2_inode_unlock(inode, 1);
+       brelse(di_bh);
+out:
+       ocfs2_run_deallocs(osb, &dealloc);
+       if (locked)
+               mutex_unlock(&inode->i_mutex);
+       ocfs2_dio_free_write_ctx(inode, dwc);
+       if (data_ac)
+               ocfs2_free_alloc_context(data_ac);
+       if (meta_ac)
+               ocfs2_free_alloc_context(meta_ac);
+}
+
+/*
+ * ocfs2_dio_end_io is called by the dio core when a dio is finished.  We're
+ * particularly interested in the aio/dio case.  We use the rw_lock DLM lock
+ * to protect io on one node from truncation on another.
+ */
+static int ocfs2_dio_end_io(struct kiocb *iocb,
+                           loff_t offset,
+                           ssize_t bytes,
+                           void *private)
+{
+       struct inode *inode = file_inode(iocb->ki_filp);
+       int level;
+
+       if (bytes <= 0)
+               return 0;
+
+       /* this io's submitter should not have unlocked this before we could */
+       BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
+
+       if (ocfs2_iocb_is_unaligned_aio(iocb)) {
+               ocfs2_iocb_clear_unaligned_aio(iocb);
+
+               mutex_unlock(&OCFS2_I(inode)->ip_unaligned_aio);
+       }
+
+       if (private)
+               ocfs2_dio_end_io_write(inode, private, offset, bytes);
+
+       ocfs2_iocb_clear_rw_locked(iocb);
+
+       level = ocfs2_iocb_rw_locked_level(iocb);
+       ocfs2_rw_unlock(inode, level);
+       return 0;
+}
+
+static ssize_t ocfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+                              loff_t offset)
+{
+       struct file *file = iocb->ki_filp;
+       struct inode *inode = file_inode(file)->i_mapping->host;
+       struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+       loff_t end = offset + iter->count;
+       get_block_t *get_block;
+
+       /*
+        * Fallback to buffered I/O if we see an inode without
+        * extents.
+        */
+       if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
+               return 0;
+
+       /* Fallback to buffered I/O if we do not support append dio. */
+       if (end > i_size_read(inode) && !ocfs2_supports_append_dio(osb))
+               return 0;
+
+       if (iov_iter_rw(iter) == READ)
+               get_block = ocfs2_get_block;
+       else
+               get_block = ocfs2_dio_get_block;
+
+       return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev,
+                                   iter, offset, get_block,
+                                   ocfs2_dio_end_io, NULL, 0);
+}
+
 const struct address_space_operations ocfs2_aops = {
        .readpage               = ocfs2_readpage,
        .readpages              = ocfs2_readpages,