tree-wide: fix assorted typos all over the place
[safe/jmp/linux-2.6] / fs / ocfs2 / refcounttree.c
index 62d21c6..d00c658 100644 (file)
@@ -32,6 +32,8 @@
 #include "dlmglue.h"
 #include "extent_map.h"
 #include "aops.h"
+#include "xattr.h"
+#include "namei.h"
 
 #include <linux/bio.h>
 #include <linux/blkdev.h>
 #include <linux/writeback.h>
 #include <linux/pagevec.h>
 #include <linux/swap.h>
+#include <linux/security.h>
+#include <linux/fsnotify.h>
+#include <linux/quotaops.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
 
 struct ocfs2_cow_context {
        struct inode *inode;
        u32 cow_start;
        u32 cow_len;
-       struct ocfs2_extent_tree di_et;
-       struct ocfs2_caching_info *ref_ci;
+       struct ocfs2_extent_tree data_et;
+       struct ocfs2_refcount_tree *ref_tree;
        struct buffer_head *ref_root_bh;
        struct ocfs2_alloc_context *meta_ac;
        struct ocfs2_alloc_context *data_ac;
        struct ocfs2_cached_dealloc_ctxt dealloc;
+       void *cow_object;
+       struct ocfs2_post_refcount *post_refcount;
+       int extra_credits;
+       int (*get_clusters)(struct ocfs2_cow_context *context,
+                           u32 v_cluster, u32 *p_cluster,
+                           u32 *num_clusters,
+                           unsigned int *extent_flags);
+       int (*cow_duplicate_clusters)(handle_t *handle,
+                                     struct ocfs2_cow_context *context,
+                                     u32 cpos, u32 old_cluster,
+                                     u32 new_cluster, u32 new_len);
 };
 
 static inline struct ocfs2_refcount_tree *
@@ -915,6 +933,42 @@ out:
 }
 
 /*
+ * Try to remove refcount tree. The mechanism is:
+ * 1) Check whether i_clusters == 0, if no, exit.
+ * 2) check whether we have i_xattr_loc in dinode. if yes, exit.
+ * 3) Check whether we have inline xattr stored outside, if yes, exit.
+ * 4) Remove the tree.
+ */
+int ocfs2_try_remove_refcount_tree(struct inode *inode,
+                                  struct buffer_head *di_bh)
+{
+       int ret;
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
+       struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+
+       down_write(&oi->ip_xattr_sem);
+       down_write(&oi->ip_alloc_sem);
+
+       if (oi->ip_clusters)
+               goto out;
+
+       if ((oi->ip_dyn_features & OCFS2_HAS_XATTR_FL) && di->i_xattr_loc)
+               goto out;
+
+       if (oi->ip_dyn_features & OCFS2_INLINE_XATTR_FL &&
+           ocfs2_has_inline_xattr_value_outside(inode, di))
+               goto out;
+
+       ret = ocfs2_remove_refcount_tree(inode, di_bh);
+       if (ret)
+               mlog_errno(ret);
+out:
+       up_write(&oi->ip_alloc_sem);
+       up_write(&oi->ip_xattr_sem);
+       return 0;
+}
+
+/*
  * Given a cpos and len, try to find the refcount record which contains cpos.
  * 1. If cpos can be found in one refcount record, return the record.
  * 2. If cpos can't be found, return a fake record which start from cpos
@@ -1099,7 +1153,7 @@ static void ocfs2_refcount_rec_merge(struct ocfs2_refcount_block *rb,
 static int ocfs2_change_refcount_rec(handle_t *handle,
                                     struct ocfs2_caching_info *ci,
                                     struct buffer_head *ref_leaf_bh,
-                                    int index, int change)
+                                    int index, int merge, int change)
 {
        int ret;
        struct ocfs2_refcount_block *rb =
@@ -1128,7 +1182,7 @@ static int ocfs2_change_refcount_rec(handle_t *handle,
                }
 
                le16_add_cpu(&rl->rl_used, -1);
-       } else
+       } else if (merge)
                ocfs2_refcount_rec_merge(rb, index);
 
        ret = ocfs2_journal_dirty(handle, ref_leaf_bh);
@@ -1604,7 +1658,7 @@ static int ocfs2_insert_refcount_rec(handle_t *handle,
                                     struct buffer_head *ref_root_bh,
                                     struct buffer_head *ref_leaf_bh,
                                     struct ocfs2_refcount_rec *rec,
-                                    int index,
+                                    int index, int merge,
                                     struct ocfs2_alloc_context *meta_ac)
 {
        int ret;
@@ -1662,7 +1716,8 @@ static int ocfs2_insert_refcount_rec(handle_t *handle,
 
        le16_add_cpu(&rf_list->rl_used, 1);
 
-       ocfs2_refcount_rec_merge(rb, index);
+       if (merge)
+               ocfs2_refcount_rec_merge(rb, index);
 
        ret = ocfs2_journal_dirty(handle, ref_leaf_bh);
        if (ret) {
@@ -1696,7 +1751,7 @@ static int ocfs2_split_refcount_rec(handle_t *handle,
                                    struct buffer_head *ref_root_bh,
                                    struct buffer_head *ref_leaf_bh,
                                    struct ocfs2_refcount_rec *split_rec,
-                                   int index,
+                                   int index, int merge,
                                    struct ocfs2_alloc_context *meta_ac,
                                    struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
@@ -1834,7 +1889,8 @@ static int ocfs2_split_refcount_rec(handle_t *handle,
                     le32_to_cpu(split_rec->r_refcount),
                     (unsigned long long)ref_leaf_bh->b_blocknr, index);
 
-               ocfs2_refcount_rec_merge(rb, index);
+               if (merge)
+                       ocfs2_refcount_rec_merge(rb, index);
        }
 
        ret = ocfs2_journal_dirty(handle, ref_leaf_bh);
@@ -1849,7 +1905,7 @@ out:
 static int __ocfs2_increase_refcount(handle_t *handle,
                                     struct ocfs2_caching_info *ci,
                                     struct buffer_head *ref_root_bh,
-                                    u64 cpos, u32 len,
+                                    u64 cpos, u32 len, int merge,
                                     struct ocfs2_alloc_context *meta_ac,
                                     struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
@@ -1889,7 +1945,8 @@ static int __ocfs2_increase_refcount(handle_t *handle,
                             "count %u\n", (unsigned long long)cpos, set_len,
                             le32_to_cpu(rec.r_refcount));
                        ret = ocfs2_change_refcount_rec(handle, ci,
-                                                       ref_leaf_bh, index, 1);
+                                                       ref_leaf_bh, index,
+                                                       merge, 1);
                        if (ret) {
                                mlog_errno(ret);
                                goto out;
@@ -1902,7 +1959,8 @@ static int __ocfs2_increase_refcount(handle_t *handle,
                             set_len);
                        ret = ocfs2_insert_refcount_rec(handle, ci, ref_root_bh,
                                                        ref_leaf_bh,
-                                                       &rec, index, meta_ac);
+                                                       &rec, index,
+                                                       merge, meta_ac);
                        if (ret) {
                                mlog_errno(ret);
                                goto out;
@@ -1920,7 +1978,7 @@ static int __ocfs2_increase_refcount(handle_t *handle,
                             set_len, le32_to_cpu(rec.r_refcount));
                        ret = ocfs2_split_refcount_rec(handle, ci,
                                                       ref_root_bh, ref_leaf_bh,
-                                                      &rec, index,
+                                                      &rec, index, merge,
                                                       meta_ac, dealloc);
                        if (ret) {
                                mlog_errno(ret);
@@ -2013,6 +2071,18 @@ out:
        return ret;
 }
 
+int ocfs2_increase_refcount(handle_t *handle,
+                           struct ocfs2_caching_info *ci,
+                           struct buffer_head *ref_root_bh,
+                           u64 cpos, u32 len,
+                           struct ocfs2_alloc_context *meta_ac,
+                           struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+       return __ocfs2_increase_refcount(handle, ci, ref_root_bh,
+                                        cpos, len, 1,
+                                        meta_ac, dealloc);
+}
+
 static int ocfs2_decrease_refcount_rec(handle_t *handle,
                                struct ocfs2_caching_info *ci,
                                struct buffer_head *ref_root_bh,
@@ -2033,7 +2103,7 @@ static int ocfs2_decrease_refcount_rec(handle_t *handle,
        if (cpos == le64_to_cpu(rec->r_cpos) &&
            len == le32_to_cpu(rec->r_clusters))
                ret = ocfs2_change_refcount_rec(handle, ci,
-                                               ref_leaf_bh, index, -1);
+                                               ref_leaf_bh, index, 1, -1);
        else {
                struct ocfs2_refcount_rec split = *rec;
                split.r_cpos = cpu_to_le64(cpos);
@@ -2049,7 +2119,7 @@ static int ocfs2_decrease_refcount_rec(handle_t *handle,
                     le32_to_cpu(rec->r_clusters));
                ret = ocfs2_split_refcount_rec(handle, ci,
                                               ref_root_bh, ref_leaf_bh,
-                                              &split, index,
+                                              &split, index, 1,
                                               meta_ac, dealloc);
        }
 
@@ -2361,7 +2431,7 @@ out:
  * we gonna touch and whether we need to create new blocks.
  *
  * Normally the refcount blocks store these refcount should be
- * continguous also, so that we can get the number easily.
+ * contiguous also, so that we can get the number easily.
  * As for meta_ac, we will at most add split 2 refcount record and
  * 2 more refcount block, so just check it in a rough way.
  *
@@ -2489,7 +2559,7 @@ static inline unsigned int ocfs2_cow_align_length(struct super_block *sb,
  * get good I/O from the resulting extent tree.
  */
 static int ocfs2_refcount_cal_cow_clusters(struct inode *inode,
-                                          struct buffer_head *di_bh,
+                                          struct ocfs2_extent_list *el,
                                           u32 cpos,
                                           u32 write_len,
                                           u32 max_cpos,
@@ -2497,8 +2567,6 @@ static int ocfs2_refcount_cal_cow_clusters(struct inode *inode,
                                           u32 *cow_len)
 {
        int ret = 0;
-       struct ocfs2_dinode *di = (struct ocfs2_dinode *) di_bh->b_data;
-       struct ocfs2_extent_list *el = &di->id2.i_list;
        int tree_height = le16_to_cpu(el->l_tree_depth), i;
        struct buffer_head *eb_bh = NULL;
        struct ocfs2_extent_block *eb = NULL;
@@ -2769,13 +2837,13 @@ static int ocfs2_clear_cow_buffer(handle_t *handle, struct buffer_head *bh)
        return 0;
 }
 
-static int ocfs2_duplicate_clusters(handle_t *handle,
-                                   struct ocfs2_cow_context *context,
-                                   u32 cpos, u32 old_cluster,
-                                   u32 new_cluster, u32 new_len)
+static int ocfs2_duplicate_clusters_by_page(handle_t *handle,
+                                           struct ocfs2_cow_context *context,
+                                           u32 cpos, u32 old_cluster,
+                                           u32 new_cluster, u32 new_len)
 {
        int ret = 0, partial;
-       struct ocfs2_caching_info *ci = context->di_et.et_ci;
+       struct ocfs2_caching_info *ci = context->data_et.et_ci;
        struct super_block *sb = ocfs2_metadata_cache_get_super(ci);
        u64 new_block = ocfs2_clusters_to_blocks(sb, new_cluster);
        struct page *page;
@@ -2842,6 +2910,65 @@ unlock:
        return ret;
 }
 
+static int ocfs2_duplicate_clusters_by_jbd(handle_t *handle,
+                                          struct ocfs2_cow_context *context,
+                                          u32 cpos, u32 old_cluster,
+                                          u32 new_cluster, u32 new_len)
+{
+       int ret = 0;
+       struct super_block *sb = context->inode->i_sb;
+       struct ocfs2_caching_info *ci = context->data_et.et_ci;
+       int i, blocks = ocfs2_clusters_to_blocks(sb, new_len);
+       u64 old_block = ocfs2_clusters_to_blocks(sb, old_cluster);
+       u64 new_block = ocfs2_clusters_to_blocks(sb, new_cluster);
+       struct ocfs2_super *osb = OCFS2_SB(sb);
+       struct buffer_head *old_bh = NULL;
+       struct buffer_head *new_bh = NULL;
+
+       mlog(0, "old_cluster %u, new %u, len %u\n", old_cluster,
+            new_cluster, new_len);
+
+       for (i = 0; i < blocks; i++, old_block++, new_block++) {
+               new_bh = sb_getblk(osb->sb, new_block);
+               if (new_bh == NULL) {
+                       ret = -EIO;
+                       mlog_errno(ret);
+                       break;
+               }
+
+               ocfs2_set_new_buffer_uptodate(ci, new_bh);
+
+               ret = ocfs2_read_block(ci, old_block, &old_bh, NULL);
+               if (ret) {
+                       mlog_errno(ret);
+                       break;
+               }
+
+               ret = ocfs2_journal_access(handle, ci, new_bh,
+                                          OCFS2_JOURNAL_ACCESS_CREATE);
+               if (ret) {
+                       mlog_errno(ret);
+                       break;
+               }
+
+               memcpy(new_bh->b_data, old_bh->b_data, sb->s_blocksize);
+               ret = ocfs2_journal_dirty(handle, new_bh);
+               if (ret) {
+                       mlog_errno(ret);
+                       break;
+               }
+
+               brelse(new_bh);
+               brelse(old_bh);
+               new_bh = NULL;
+               old_bh = NULL;
+       }
+
+       brelse(new_bh);
+       brelse(old_bh);
+       return ret;
+}
+
 static int ocfs2_clear_ext_refcount(handle_t *handle,
                                    struct ocfs2_extent_tree *et,
                                    u32 cpos, u32 p_cluster, u32 len,
@@ -2909,7 +3036,7 @@ static int ocfs2_replace_clusters(handle_t *handle,
                                  unsigned int ext_flags)
 {
        int ret;
-       struct ocfs2_caching_info *ci = context->di_et.et_ci;
+       struct ocfs2_caching_info *ci = context->data_et.et_ci;
        u64 ino = ocfs2_metadata_cache_owner(ci);
 
        mlog(0, "inode %llu, cpos %u, old %u, new %u, len %u, ext_flags %u\n",
@@ -2917,15 +3044,15 @@ static int ocfs2_replace_clusters(handle_t *handle,
 
        /*If the old clusters is unwritten, no need to duplicate. */
        if (!(ext_flags & OCFS2_EXT_UNWRITTEN)) {
-               ret = ocfs2_duplicate_clusters(handle, context, cpos,
-                                              old, new, len);
+               ret = context->cow_duplicate_clusters(handle, context, cpos,
+                                                     old, new, len);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }
        }
 
-       ret = ocfs2_clear_ext_refcount(handle, &context->di_et,
+       ret = ocfs2_clear_ext_refcount(handle, &context->data_et,
                                       cpos, new, len, ext_flags,
                                       context->meta_ac, &context->dealloc);
        if (ret)
@@ -2983,6 +3110,15 @@ static int ocfs2_cow_sync_writeback(struct super_block *sb,
        return ret;
 }
 
+static int ocfs2_di_get_clusters(struct ocfs2_cow_context *context,
+                                u32 v_cluster, u32 *p_cluster,
+                                u32 *num_clusters,
+                                unsigned int *extent_flags)
+{
+       return ocfs2_get_clusters(context->inode, v_cluster, p_cluster,
+                                 num_clusters, extent_flags);
+}
+
 static int ocfs2_make_clusters_writable(struct super_block *sb,
                                        struct ocfs2_cow_context *context,
                                        u32 cpos, u32 p_cluster,
@@ -2994,14 +3130,15 @@ static int ocfs2_make_clusters_writable(struct super_block *sb,
        struct ocfs2_super *osb = OCFS2_SB(sb);
        handle_t *handle;
        struct buffer_head *ref_leaf_bh = NULL;
+       struct ocfs2_caching_info *ref_ci = &context->ref_tree->rf_ci;
        struct ocfs2_refcount_rec rec;
 
        mlog(0, "cpos %u, p_cluster %u, num_clusters %u, e_flags %u\n",
             cpos, p_cluster, num_clusters, e_flags);
 
        ret = ocfs2_lock_refcount_allocators(sb, p_cluster, num_clusters,
-                                            &context->di_et,
-                                            context->ref_ci,
+                                            &context->data_et,
+                                            ref_ci,
                                             context->ref_root_bh,
                                             &context->meta_ac,
                                             &context->data_ac, &credits);
@@ -3010,6 +3147,10 @@ static int ocfs2_make_clusters_writable(struct super_block *sb,
                return ret;
        }
 
+       if (context->post_refcount)
+               credits += context->post_refcount->credits;
+
+       credits += context->extra_credits;
        handle = ocfs2_start_trans(osb, credits);
        if (IS_ERR(handle)) {
                ret = PTR_ERR(handle);
@@ -3018,8 +3159,7 @@ static int ocfs2_make_clusters_writable(struct super_block *sb,
        }
 
        while (num_clusters) {
-               ret = ocfs2_get_refcount_rec(context->ref_ci,
-                                            context->ref_root_bh,
+               ret = ocfs2_get_refcount_rec(ref_ci, context->ref_root_bh,
                                             p_cluster, num_clusters,
                                             &rec, &index, &ref_leaf_bh);
                if (ret) {
@@ -3041,7 +3181,8 @@ static int ocfs2_make_clusters_writable(struct super_block *sb,
                 */
                if (le32_to_cpu(rec.r_refcount) == 1) {
                        delete = 0;
-                       ret = ocfs2_clear_ext_refcount(handle, &context->di_et,
+                       ret = ocfs2_clear_ext_refcount(handle,
+                                                      &context->data_et,
                                                       cpos, p_cluster,
                                                       set_len, e_flags,
                                                       context->meta_ac,
@@ -3072,7 +3213,7 @@ static int ocfs2_make_clusters_writable(struct super_block *sb,
                        set_len = new_len;
                }
 
-               ret = __ocfs2_decrease_refcount(handle, context->ref_ci,
+               ret = __ocfs2_decrease_refcount(handle, ref_ci,
                                                context->ref_root_bh,
                                                p_cluster, set_len,
                                                context->meta_ac,
@@ -3089,13 +3230,25 @@ static int ocfs2_make_clusters_writable(struct super_block *sb,
                ref_leaf_bh = NULL;
        }
 
+       /* handle any post_cow action. */
+       if (context->post_refcount && context->post_refcount->func) {
+               ret = context->post_refcount->func(context->inode, handle,
+                                               context->post_refcount->para);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out_commit;
+               }
+       }
+
        /*
         * Here we should write the new page out first if we are
         * in write-back mode.
         */
-       ret = ocfs2_cow_sync_writeback(sb, context, cpos, num_clusters);
-       if (ret)
-               mlog_errno(ret);
+       if (context->get_clusters == ocfs2_di_get_clusters) {
+               ret = ocfs2_cow_sync_writeback(sb, context, cpos, num_clusters);
+               if (ret)
+                       mlog_errno(ret);
+       }
 
 out_commit:
        ocfs2_commit_trans(osb, handle);
@@ -3114,17 +3267,14 @@ out:
        return ret;
 }
 
-static int ocfs2_replace_cow(struct inode *inode,
-                            struct buffer_head *di_bh,
-                            struct buffer_head *ref_root_bh,
-                            struct ocfs2_caching_info *ref_ci,
-                            u32 cow_start, u32 cow_len)
+static int ocfs2_replace_cow(struct ocfs2_cow_context *context)
 {
        int ret = 0;
-       u32 p_cluster, num_clusters, start = cow_start;
+       struct inode *inode = context->inode;
+       u32 cow_start = context->cow_start, cow_len = context->cow_len;
+       u32 p_cluster, num_clusters;
        unsigned int ext_flags;
        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
-       struct ocfs2_cow_context *context;
 
        if (!ocfs2_refcount_tree(OCFS2_SB(inode->i_sb))) {
                ocfs2_error(inode->i_sb, "Inode %lu want to use refcount "
@@ -3133,26 +3283,11 @@ static int ocfs2_replace_cow(struct inode *inode,
                return -EROFS;
        }
 
-       context = kzalloc(sizeof(struct ocfs2_cow_context), GFP_NOFS);
-       if (!context) {
-               ret = -ENOMEM;
-               mlog_errno(ret);
-               return ret;
-       }
-
-       context->inode = inode;
-       context->cow_start = cow_start;
-       context->cow_len = cow_len;
-       context->ref_ci = ref_ci;
-       context->ref_root_bh = ref_root_bh;
-
        ocfs2_init_dealloc_ctxt(&context->dealloc);
-       ocfs2_init_dinode_extent_tree(&context->di_et,
-                                     INODE_CACHE(inode), di_bh);
 
        while (cow_len) {
-               ret = ocfs2_get_clusters(inode, cow_start, &p_cluster,
-                                        &num_clusters, &ext_flags);
+               ret = context->get_clusters(context, cow_start, &p_cluster,
+                                           &num_clusters, &ext_flags);
                if (ret) {
                        mlog_errno(ret);
                        break;
@@ -3175,20 +3310,11 @@ static int ocfs2_replace_cow(struct inode *inode,
                cow_start += num_clusters;
        }
 
-
-       /*
-        * truncate the extent map here since no matter whether we meet with
-        * any error during the action, we shouldn't trust cached extent map
-        * any more.
-        */
-       ocfs2_extent_map_trunc(inode, start);
-
        if (ocfs2_dealloc_has_cluster(&context->dealloc)) {
                ocfs2_schedule_truncate_log_flush(osb, 1);
                ocfs2_run_deallocs(osb, &context->dealloc);
        }
 
-       kfree(context);
        return ret;
 }
 
@@ -3208,10 +3334,11 @@ static int ocfs2_refcount_cow_hunk(struct inode *inode,
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
        struct buffer_head *ref_root_bh = NULL;
        struct ocfs2_refcount_tree *ref_tree;
+       struct ocfs2_cow_context *context = NULL;
 
        BUG_ON(!(oi->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL));
 
-       ret = ocfs2_refcount_cal_cow_clusters(inode, di_bh,
+       ret = ocfs2_refcount_cal_cow_clusters(inode, &di->id2.i_list,
                                              cpos, write_len, max_cpos,
                                              &cow_start, &cow_len);
        if (ret) {
@@ -3225,6 +3352,13 @@ static int ocfs2_refcount_cow_hunk(struct inode *inode,
 
        BUG_ON(cow_len == 0);
 
+       context = kzalloc(sizeof(struct ocfs2_cow_context), GFP_NOFS);
+       if (!context) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto out;
+       }
+
        ret = ocfs2_lock_refcount_tree(osb, le64_to_cpu(di->i_refcount_loc),
                                       1, &ref_tree, &ref_root_bh);
        if (ret) {
@@ -3232,14 +3366,32 @@ static int ocfs2_refcount_cow_hunk(struct inode *inode,
                goto out;
        }
 
-       ret = ocfs2_replace_cow(inode, di_bh, ref_root_bh, &ref_tree->rf_ci,
-                               cow_start, cow_len);
+       context->inode = inode;
+       context->cow_start = cow_start;
+       context->cow_len = cow_len;
+       context->ref_tree = ref_tree;
+       context->ref_root_bh = ref_root_bh;
+       context->cow_duplicate_clusters = ocfs2_duplicate_clusters_by_page;
+       context->get_clusters = ocfs2_di_get_clusters;
+
+       ocfs2_init_dinode_extent_tree(&context->data_et,
+                                     INODE_CACHE(inode), di_bh);
+
+       ret = ocfs2_replace_cow(context);
        if (ret)
                mlog_errno(ret);
 
+       /*
+        * truncate the extent map here since no matter whether we meet with
+        * any error during the action, we shouldn't trust cached extent map
+        * any more.
+        */
+       ocfs2_extent_map_trunc(inode, cow_start);
+
        ocfs2_unlock_refcount_tree(osb, ref_tree, 1);
        brelse(ref_root_bh);
 out:
+       kfree(context);
        return ret;
 }
 
@@ -3283,6 +3435,167 @@ int ocfs2_refcount_cow(struct inode *inode,
        return ret;
 }
 
+static int ocfs2_xattr_value_get_clusters(struct ocfs2_cow_context *context,
+                                         u32 v_cluster, u32 *p_cluster,
+                                         u32 *num_clusters,
+                                         unsigned int *extent_flags)
+{
+       struct inode *inode = context->inode;
+       struct ocfs2_xattr_value_root *xv = context->cow_object;
+
+       return ocfs2_xattr_get_clusters(inode, v_cluster, p_cluster,
+                                       num_clusters, &xv->xr_list,
+                                       extent_flags);
+}
+
+/*
+ * Given a xattr value root, calculate the most meta/credits we need for
+ * refcount tree change if we truncate it to 0.
+ */
+int ocfs2_refcounted_xattr_delete_need(struct inode *inode,
+                                      struct ocfs2_caching_info *ref_ci,
+                                      struct buffer_head *ref_root_bh,
+                                      struct ocfs2_xattr_value_root *xv,
+                                      int *meta_add, int *credits)
+{
+       int ret = 0, index, ref_blocks = 0;
+       u32 p_cluster, num_clusters;
+       u32 cpos = 0, clusters = le32_to_cpu(xv->xr_clusters);
+       struct ocfs2_refcount_block *rb;
+       struct ocfs2_refcount_rec rec;
+       struct buffer_head *ref_leaf_bh = NULL;
+
+       while (cpos < clusters) {
+               ret = ocfs2_xattr_get_clusters(inode, cpos, &p_cluster,
+                                              &num_clusters, &xv->xr_list,
+                                              NULL);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               cpos += num_clusters;
+
+               while (num_clusters) {
+                       ret = ocfs2_get_refcount_rec(ref_ci, ref_root_bh,
+                                                    p_cluster, num_clusters,
+                                                    &rec, &index,
+                                                    &ref_leaf_bh);
+                       if (ret) {
+                               mlog_errno(ret);
+                               goto out;
+                       }
+
+                       BUG_ON(!rec.r_refcount);
+
+                       rb = (struct ocfs2_refcount_block *)ref_leaf_bh->b_data;
+
+                       /*
+                        * We really don't know whether the other clusters is in
+                        * this refcount block or not, so just take the worst
+                        * case that all the clusters are in this block and each
+                        * one will split a refcount rec, so totally we need
+                        * clusters * 2 new refcount rec.
+                        */
+                       if (le64_to_cpu(rb->rf_records.rl_used) + clusters * 2 >
+                           le16_to_cpu(rb->rf_records.rl_count))
+                               ref_blocks++;
+
+                       *credits += 1;
+                       brelse(ref_leaf_bh);
+                       ref_leaf_bh = NULL;
+
+                       if (num_clusters <= le32_to_cpu(rec.r_clusters))
+                               break;
+                       else
+                               num_clusters -= le32_to_cpu(rec.r_clusters);
+                       p_cluster += num_clusters;
+               }
+       }
+
+       *meta_add += ref_blocks;
+       if (!ref_blocks)
+               goto out;
+
+       rb = (struct ocfs2_refcount_block *)ref_root_bh->b_data;
+       if (le32_to_cpu(rb->rf_flags) & OCFS2_REFCOUNT_TREE_FL)
+               *credits += OCFS2_EXPAND_REFCOUNT_TREE_CREDITS;
+       else {
+               struct ocfs2_extent_tree et;
+
+               ocfs2_init_refcount_extent_tree(&et, ref_ci, ref_root_bh);
+               *credits += ocfs2_calc_extend_credits(inode->i_sb,
+                                                     et.et_root_el,
+                                                     ref_blocks);
+       }
+
+out:
+       brelse(ref_leaf_bh);
+       return ret;
+}
+
+/*
+ * Do CoW for xattr.
+ */
+int ocfs2_refcount_cow_xattr(struct inode *inode,
+                            struct ocfs2_dinode *di,
+                            struct ocfs2_xattr_value_buf *vb,
+                            struct ocfs2_refcount_tree *ref_tree,
+                            struct buffer_head *ref_root_bh,
+                            u32 cpos, u32 write_len,
+                            struct ocfs2_post_refcount *post)
+{
+       int ret;
+       struct ocfs2_xattr_value_root *xv = vb->vb_xv;
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
+       struct ocfs2_cow_context *context = NULL;
+       u32 cow_start, cow_len;
+
+       BUG_ON(!(oi->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL));
+
+       ret = ocfs2_refcount_cal_cow_clusters(inode, &xv->xr_list,
+                                             cpos, write_len, UINT_MAX,
+                                             &cow_start, &cow_len);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       BUG_ON(cow_len == 0);
+
+       context = kzalloc(sizeof(struct ocfs2_cow_context), GFP_NOFS);
+       if (!context) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto out;
+       }
+
+       context->inode = inode;
+       context->cow_start = cow_start;
+       context->cow_len = cow_len;
+       context->ref_tree = ref_tree;
+       context->ref_root_bh = ref_root_bh;;
+       context->cow_object = xv;
+
+       context->cow_duplicate_clusters = ocfs2_duplicate_clusters_by_jbd;
+       /* We need the extra credits for duplicate_clusters by jbd. */
+       context->extra_credits =
+               ocfs2_clusters_to_blocks(inode->i_sb, 1) * cow_len;
+       context->get_clusters = ocfs2_xattr_value_get_clusters;
+       context->post_refcount = post;
+
+       ocfs2_init_xattr_value_extent_tree(&context->data_et,
+                                          INODE_CACHE(inode), vb);
+
+       ret = ocfs2_replace_cow(context);
+       if (ret)
+               mlog_errno(ret);
+
+out:
+       kfree(context);
+       return ret;
+}
+
 /*
  * Insert a new extent into refcount tree and mark a extent rec
  * as refcounted in the dinode tree.
@@ -3292,7 +3605,8 @@ int ocfs2_add_refcount_flag(struct inode *inode,
                            struct ocfs2_caching_info *ref_ci,
                            struct buffer_head *ref_root_bh,
                            u32 cpos, u32 p_cluster, u32 num_clusters,
-                           struct ocfs2_cached_dealloc_ctxt *dealloc)
+                           struct ocfs2_cached_dealloc_ctxt *dealloc,
+                           struct ocfs2_post_refcount *post)
 {
        int ret;
        handle_t *handle;
@@ -3321,6 +3635,9 @@ int ocfs2_add_refcount_flag(struct inode *inode,
                }
        }
 
+       if (post)
+               credits += post->credits;
+
        handle = ocfs2_start_trans(osb, credits);
        if (IS_ERR(handle)) {
                ret = PTR_ERR(handle);
@@ -3337,10 +3654,18 @@ int ocfs2_add_refcount_flag(struct inode *inode,
        }
 
        ret = __ocfs2_increase_refcount(handle, ref_ci, ref_root_bh,
-                                       p_cluster, num_clusters,
+                                       p_cluster, num_clusters, 0,
                                        meta_ac, dealloc);
-       if (ret)
+       if (ret) {
                mlog_errno(ret);
+               goto out_commit;
+       }
+
+       if (post && post->func) {
+               ret = post->func(inode, handle, post->para);
+               if (ret)
+                       mlog_errno(ret);
+       }
 
 out_commit:
        ocfs2_commit_trans(osb, handle);
@@ -3433,7 +3758,7 @@ static int ocfs2_attach_refcount_tree(struct inode *inode,
                                                      &ref_tree->rf_ci,
                                                      ref_root_bh, cpos,
                                                      p_cluster, num_clusters,
-                                                     &dealloc);
+                                                     &dealloc, NULL);
                        if (ret) {
                                mlog_errno(ret);
                                goto unlock;
@@ -3444,6 +3769,17 @@ static int ocfs2_attach_refcount_tree(struct inode *inode,
                cpos += num_clusters;
        }
 
+       if (oi->ip_dyn_features & OCFS2_HAS_XATTR_FL) {
+               ret = ocfs2_xattr_attach_refcount_tree(inode, di_bh,
+                                                      &ref_tree->rf_ci,
+                                                      ref_root_bh,
+                                                      &dealloc);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto unlock;
+               }
+       }
+
        if (data_changed) {
                ret = ocfs2_change_ctime(inode, di_bh);
                if (ret)
@@ -3508,9 +3844,9 @@ static int ocfs2_add_refcounted_extent(struct inode *inode,
                goto out_commit;
        }
 
-       ret = __ocfs2_increase_refcount(handle, ref_ci, ref_root_bh,
-                                       p_cluster, num_clusters,
-                                       meta_ac, dealloc);
+       ret = ocfs2_increase_refcount(handle, ref_ci, ref_root_bh,
+                                     p_cluster, num_clusters,
+                                     meta_ac, dealloc);
        if (ret)
                mlog_errno(ret);
 
@@ -3574,7 +3910,8 @@ out:
 static int ocfs2_complete_reflink(struct inode *s_inode,
                                  struct buffer_head *s_bh,
                                  struct inode *t_inode,
-                                 struct buffer_head *t_bh)
+                                 struct buffer_head *t_bh,
+                                 bool preserve)
 {
        int ret;
        handle_t *handle;
@@ -3609,22 +3946,26 @@ static int ocfs2_complete_reflink(struct inode *s_inode,
        di->i_size = s_di->i_size;
        di->i_dyn_features = s_di->i_dyn_features;
        di->i_attr = s_di->i_attr;
-       di->i_uid = s_di->i_uid;
-       di->i_gid = s_di->i_gid;
-       di->i_mode = s_di->i_mode;
 
-       /*
-        * update time.
-        * we want mtime to appear identical to the source and update ctime.
-        */
-       t_inode->i_ctime = CURRENT_TIME;
+       if (preserve) {
+               di->i_uid = s_di->i_uid;
+               di->i_gid = s_di->i_gid;
+               di->i_mode = s_di->i_mode;
+
+               /*
+                * update time.
+                * we want mtime to appear identical to the source and
+                * update ctime.
+                */
+               t_inode->i_ctime = CURRENT_TIME;
 
-       di->i_ctime = cpu_to_le64(t_inode->i_ctime.tv_sec);
-       di->i_ctime_nsec = cpu_to_le32(t_inode->i_ctime.tv_nsec);
+               di->i_ctime = cpu_to_le64(t_inode->i_ctime.tv_sec);
+               di->i_ctime_nsec = cpu_to_le32(t_inode->i_ctime.tv_nsec);
 
-       t_inode->i_mtime = s_inode->i_mtime;
-       di->i_mtime = s_di->i_mtime;
-       di->i_mtime_nsec = s_di->i_mtime_nsec;
+               t_inode->i_mtime = s_inode->i_mtime;
+               di->i_mtime = s_di->i_mtime;
+               di->i_mtime_nsec = s_di->i_mtime_nsec;
+       }
 
        ocfs2_journal_dirty(handle, t_bh);
 
@@ -3636,7 +3977,8 @@ out_commit:
 static int ocfs2_create_reflink_node(struct inode *s_inode,
                                     struct buffer_head *s_bh,
                                     struct inode *t_inode,
-                                    struct buffer_head *t_bh)
+                                    struct buffer_head *t_bh,
+                                    bool preserve)
 {
        int ret;
        struct buffer_head *ref_root_bh = NULL;
@@ -3671,7 +4013,7 @@ static int ocfs2_create_reflink_node(struct inode *s_inode,
                goto out_unlock_refcount;
        }
 
-       ret = ocfs2_complete_reflink(s_inode, s_bh, t_inode, t_bh);
+       ret = ocfs2_complete_reflink(s_inode, s_bh, t_inode, t_bh, preserve);
        if (ret)
                mlog_errno(ret);
 
@@ -3686,3 +4028,286 @@ out:
 
        return ret;
 }
+
+static int __ocfs2_reflink(struct dentry *old_dentry,
+                          struct buffer_head *old_bh,
+                          struct inode *new_inode,
+                          bool preserve)
+{
+       int ret;
+       struct inode *inode = old_dentry->d_inode;
+       struct buffer_head *new_bh = NULL;
+
+       ret = filemap_fdatawrite(inode->i_mapping);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       ret = ocfs2_attach_refcount_tree(inode, old_bh);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       mutex_lock(&new_inode->i_mutex);
+       ret = ocfs2_inode_lock(new_inode, &new_bh, 1);
+       if (ret) {
+               mlog_errno(ret);
+               goto out_unlock;
+       }
+
+       ret = ocfs2_create_reflink_node(inode, old_bh,
+                                       new_inode, new_bh, preserve);
+       if (ret) {
+               mlog_errno(ret);
+               goto inode_unlock;
+       }
+
+       if (OCFS2_I(inode)->ip_dyn_features & OCFS2_HAS_XATTR_FL) {
+               ret = ocfs2_reflink_xattrs(inode, old_bh,
+                                          new_inode, new_bh,
+                                          preserve);
+               if (ret)
+                       mlog_errno(ret);
+       }
+inode_unlock:
+       ocfs2_inode_unlock(new_inode, 1);
+       brelse(new_bh);
+out_unlock:
+       mutex_unlock(&new_inode->i_mutex);
+out:
+       if (!ret) {
+               ret = filemap_fdatawait(inode->i_mapping);
+               if (ret)
+                       mlog_errno(ret);
+       }
+       return ret;
+}
+
+static int ocfs2_reflink(struct dentry *old_dentry, struct inode *dir,
+                        struct dentry *new_dentry, bool preserve)
+{
+       int error;
+       struct inode *inode = old_dentry->d_inode;
+       struct buffer_head *old_bh = NULL;
+       struct inode *new_orphan_inode = NULL;
+
+       if (!ocfs2_refcount_tree(OCFS2_SB(inode->i_sb)))
+               return -EOPNOTSUPP;
+
+       error = ocfs2_create_inode_in_orphan(dir, inode->i_mode,
+                                            &new_orphan_inode);
+       if (error) {
+               mlog_errno(error);
+               goto out;
+       }
+
+       error = ocfs2_inode_lock(inode, &old_bh, 1);
+       if (error) {
+               mlog_errno(error);
+               goto out;
+       }
+
+       down_write(&OCFS2_I(inode)->ip_xattr_sem);
+       down_write(&OCFS2_I(inode)->ip_alloc_sem);
+       error = __ocfs2_reflink(old_dentry, old_bh,
+                               new_orphan_inode, preserve);
+       up_write(&OCFS2_I(inode)->ip_alloc_sem);
+       up_write(&OCFS2_I(inode)->ip_xattr_sem);
+
+       ocfs2_inode_unlock(inode, 1);
+       brelse(old_bh);
+
+       if (error) {
+               mlog_errno(error);
+               goto out;
+       }
+
+       /* If the security isn't preserved, we need to re-initialize them. */
+       if (!preserve) {
+               error = ocfs2_init_security_and_acl(dir, new_orphan_inode);
+               if (error)
+                       mlog_errno(error);
+       }
+out:
+       if (!error) {
+               error = ocfs2_mv_orphaned_inode_to_new(dir, new_orphan_inode,
+                                                      new_dentry);
+               if (error)
+                       mlog_errno(error);
+       }
+
+       if (new_orphan_inode) {
+               /*
+                * We need to open_unlock the inode no matter whether we
+                * succeed or not, so that other nodes can delete it later.
+                */
+               ocfs2_open_unlock(new_orphan_inode);
+               if (error)
+                       iput(new_orphan_inode);
+       }
+
+       return error;
+}
+
+/*
+ * Below here are the bits used by OCFS2_IOC_REFLINK() to fake
+ * sys_reflink().  This will go away when vfs_reflink() exists in
+ * fs/namei.c.
+ */
+
+/* copied from may_create in VFS. */
+static inline int ocfs2_may_create(struct inode *dir, struct dentry *child)
+{
+       if (child->d_inode)
+               return -EEXIST;
+       if (IS_DEADDIR(dir))
+               return -ENOENT;
+       return inode_permission(dir, MAY_WRITE | MAY_EXEC);
+}
+
+/* copied from user_path_parent. */
+static int ocfs2_user_path_parent(const char __user *path,
+                                 struct nameidata *nd, char **name)
+{
+       char *s = getname(path);
+       int error;
+
+       if (IS_ERR(s))
+               return PTR_ERR(s);
+
+       error = path_lookup(s, LOOKUP_PARENT, nd);
+       if (error)
+               putname(s);
+       else
+               *name = s;
+
+       return error;
+}
+
+/**
+ * ocfs2_vfs_reflink - Create a reference-counted link
+ *
+ * @old_dentry:        source dentry + inode
+ * @dir:       directory to create the target
+ * @new_dentry:        target dentry
+ * @preserve:  if true, preserve all file attributes
+ */
+int ocfs2_vfs_reflink(struct dentry *old_dentry, struct inode *dir,
+                     struct dentry *new_dentry, bool preserve)
+{
+       struct inode *inode = old_dentry->d_inode;
+       int error;
+
+       if (!inode)
+               return -ENOENT;
+
+       error = ocfs2_may_create(dir, new_dentry);
+       if (error)
+               return error;
+
+       if (dir->i_sb != inode->i_sb)
+               return -EXDEV;
+
+       /*
+        * A reflink to an append-only or immutable file cannot be created.
+        */
+       if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
+               return -EPERM;
+
+       /* Only regular files can be reflinked. */
+       if (!S_ISREG(inode->i_mode))
+               return -EPERM;
+
+       /*
+        * If the caller wants to preserve ownership, they require the
+        * rights to do so.
+        */
+       if (preserve) {
+               if ((current_fsuid() != inode->i_uid) && !capable(CAP_CHOWN))
+                       return -EPERM;
+               if (!in_group_p(inode->i_gid) && !capable(CAP_CHOWN))
+                       return -EPERM;
+       }
+
+       /*
+        * If the caller is modifying any aspect of the attributes, they
+        * are not creating a snapshot.  They need read permission on the
+        * file.
+        */
+       if (!preserve) {
+               error = inode_permission(inode, MAY_READ);
+               if (error)
+                       return error;
+       }
+
+       mutex_lock(&inode->i_mutex);
+       vfs_dq_init(dir);
+       error = ocfs2_reflink(old_dentry, dir, new_dentry, preserve);
+       mutex_unlock(&inode->i_mutex);
+       if (!error)
+               fsnotify_create(dir, new_dentry);
+       return error;
+}
+/*
+ * Most codes are copied from sys_linkat.
+ */
+int ocfs2_reflink_ioctl(struct inode *inode,
+                       const char __user *oldname,
+                       const char __user *newname,
+                       bool preserve)
+{
+       struct dentry *new_dentry;
+       struct nameidata nd;
+       struct path old_path;
+       int error;
+       char *to = NULL;
+
+       if (!ocfs2_refcount_tree(OCFS2_SB(inode->i_sb)))
+               return -EOPNOTSUPP;
+
+       error = user_path_at(AT_FDCWD, oldname, 0, &old_path);
+       if (error) {
+               mlog_errno(error);
+               return error;
+       }
+
+       error = ocfs2_user_path_parent(newname, &nd, &to);
+       if (error) {
+               mlog_errno(error);
+               goto out;
+       }
+
+       error = -EXDEV;
+       if (old_path.mnt != nd.path.mnt)
+               goto out_release;
+       new_dentry = lookup_create(&nd, 0);
+       error = PTR_ERR(new_dentry);
+       if (IS_ERR(new_dentry)) {
+               mlog_errno(error);
+               goto out_unlock;
+       }
+
+       error = mnt_want_write(nd.path.mnt);
+       if (error) {
+               mlog_errno(error);
+               goto out_dput;
+       }
+
+       error = ocfs2_vfs_reflink(old_path.dentry,
+                                 nd.path.dentry->d_inode,
+                                 new_dentry, preserve);
+       mnt_drop_write(nd.path.mnt);
+out_dput:
+       dput(new_dentry);
+out_unlock:
+       mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
+out_release:
+       path_put(&nd.path);
+       putname(to);
+out:
+       path_put(&old_path);
+
+       return error;
+}