ocfs2: support partial clone range and dedupe range

Change the ocfs2 remap code to allow for returning partial results.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

3 files changed, 46 insertions, 45 deletions

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index fbaeafe44b5f..8125c5ccf821 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2531,14 +2531,11 @@ static loff_t ocfs2_remap_file_range(struct file *file_in, loff_t pos_in,
                                      struct file *file_out, loff_t pos_out,
                                      loff_t len, unsigned int remap_flags)
 {
-        int ret;
-
         if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
                 return -EINVAL;
 
-        ret = ocfs2_reflink_remap_range(file_in, pos_in, file_out, pos_out,
-                                        len, remap_flags);
-        return ret < 0 ? ret : len;
+        return ocfs2_reflink_remap_range(file_in, pos_in, file_out, pos_out,
+                        len, remap_flags);
 }
 
 const struct inode_operations ocfs2_file_iops = {
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 7c709229e108..c7409578657b 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -4507,14 +4507,14 @@ out_commit:
 }
 
 /* Remap the range pos_in:len in s_inode to pos_out:len in t_inode. */
-static int ocfs2_reflink_remap_extent(struct inode *s_inode,
-                                      struct buffer_head *s_bh,
-                                      loff_t pos_in,
-                                      struct inode *t_inode,
-                                      struct buffer_head *t_bh,
-                                      loff_t pos_out,
-                                      loff_t len,
-                                      struct ocfs2_cached_dealloc_ctxt *dealloc)
+static loff_t ocfs2_reflink_remap_extent(struct inode *s_inode,
+                                         struct buffer_head *s_bh,
+                                         loff_t pos_in,
+                                         struct inode *t_inode,
+                                         struct buffer_head *t_bh,
+                                         loff_t pos_out,
+                                         loff_t len,
+                                         struct ocfs2_cached_dealloc_ctxt *dealloc)
 {
         struct ocfs2_extent_tree s_et;
         struct ocfs2_extent_tree t_et;
@@ -4522,8 +4522,9 @@ static int ocfs2_reflink_remap_extent(struct inode *s_inode,
         struct buffer_head *ref_root_bh = NULL;
         struct ocfs2_refcount_tree *ref_tree;
         struct ocfs2_super *osb;
+        loff_t remapped_bytes = 0;
         loff_t pstart, plen;
-        u32 p_cluster, num_clusters, slast, spos, tpos;
+        u32 p_cluster, num_clusters, slast, spos, tpos, remapped_clus = 0;
         unsigned int ext_flags;
         int ret = 0;
 
@@ -4605,30 +4606,34 @@ static int ocfs2_reflink_remap_extent(struct inode *s_inode,
 next_loop:
                 spos += num_clusters;
                 tpos += num_clusters;
+                remapped_clus += num_clusters;
         }
 
-out:
-        return ret;
+        goto out;
 out_unlock_refcount:
         ocfs2_unlock_refcount_tree(osb, ref_tree, 1);
         brelse(ref_root_bh);
-        return ret;
+out:
+        remapped_bytes = ocfs2_clusters_to_bytes(t_inode->i_sb, remapped_clus);
+        remapped_bytes = min_t(loff_t, len, remapped_bytes);
+
+        return remapped_bytes > 0 ? remapped_bytes : ret;
 }
 
 /* Set up refcount tree and remap s_inode to t_inode. */
-static int ocfs2_reflink_remap_blocks(struct inode *s_inode,
-                                      struct buffer_head *s_bh,
-                                      loff_t pos_in,
-                                      struct inode *t_inode,
-                                      struct buffer_head *t_bh,
-                                      loff_t pos_out,
-                                      loff_t len)
+static loff_t ocfs2_reflink_remap_blocks(struct inode *s_inode,
+                                         struct buffer_head *s_bh,
+                                         loff_t pos_in,
+                                         struct inode *t_inode,
+                                         struct buffer_head *t_bh,
+                                         loff_t pos_out,
+                                         loff_t len)
 {
         struct ocfs2_cached_dealloc_ctxt dealloc;
         struct ocfs2_super *osb;
         struct ocfs2_dinode *dis;
         struct ocfs2_dinode *dit;
-        int ret;
+        loff_t ret;
 
         osb = OCFS2_SB(s_inode->i_sb);
         dis = (struct ocfs2_dinode *)s_bh->b_data;
@@ -4700,7 +4705,7 @@ static int ocfs2_reflink_remap_blocks(struct inode *s_inode,
         /* Actually remap extents now. */
         ret = ocfs2_reflink_remap_extent(s_inode, s_bh, pos_in, t_inode, t_bh,
                                          pos_out, len, &dealloc);
-        if (ret) {
+        if (ret < 0) {
                 mlog_errno(ret);
                 goto out;
         }
@@ -4820,18 +4825,19 @@ static void ocfs2_reflink_inodes_unlock(struct inode *s_inode,
 }
 
 /* Link a range of blocks from one file to another. */
-int ocfs2_reflink_remap_range(struct file *file_in,
-                              loff_t pos_in,
-                              struct file *file_out,
-                              loff_t pos_out,
-                              loff_t len,
-                              unsigned int remap_flags)
+loff_t ocfs2_reflink_remap_range(struct file *file_in,
+                                 loff_t pos_in,
+                                 struct file *file_out,
+                                 loff_t pos_out,
+                                 loff_t len,
+                                 unsigned int remap_flags)
 {
         struct inode *inode_in = file_inode(file_in);
         struct inode *inode_out = file_inode(file_out);
         struct ocfs2_super *osb = OCFS2_SB(inode_in->i_sb);
         struct buffer_head *in_bh = NULL, *out_bh = NULL;
         bool same_inode = (inode_in == inode_out);
+        loff_t remapped = 0;
         ssize_t ret;
 
         if (!ocfs2_refcount_tree(osb))
@@ -4866,12 +4872,13 @@ int ocfs2_reflink_remap_range(struct file *file_in,
                                    round_down(pos_out, PAGE_SIZE),
                                    round_up(pos_out + len, PAGE_SIZE) - 1);
 
-        ret = ocfs2_reflink_remap_blocks(inode_in, in_bh, pos_in, inode_out,
-                                         out_bh, pos_out, len);
+        remapped = ocfs2_reflink_remap_blocks(inode_in, in_bh, pos_in,
+                        inode_out, out_bh, pos_out, len);
         up_write(&OCFS2_I(inode_in)->ip_alloc_sem);
         if (!same_inode)
                 up_write(&OCFS2_I(inode_out)->ip_alloc_sem);
-        if (ret) {
+        if (remapped < 0) {
+                ret = remapped;
                 mlog_errno(ret);
                 goto out_unlock;
         }
@@ -4889,10 +4896,7 @@ int ocfs2_reflink_remap_range(struct file *file_in,
                 goto out_unlock;
         }
 
-        ocfs2_reflink_inodes_unlock(inode_in, in_bh, inode_out, out_bh);
-        return 0;
-
 out_unlock:
         ocfs2_reflink_inodes_unlock(inode_in, in_bh, inode_out, out_bh);
-        return ret;
+        return remapped > 0 ? remapped : ret;
 }
diff --git a/fs/ocfs2/refcounttree.h b/fs/ocfs2/refcounttree.h
index eb65c1d0843c..9e64daba395d 100644
--- a/fs/ocfs2/refcounttree.h
+++ b/fs/ocfs2/refcounttree.h
@@ -115,11 +115,11 @@ int ocfs2_reflink_ioctl(struct inode *inode,
                         const char __user *oldname,
                         const char __user *newname,
                         bool preserve);
-int ocfs2_reflink_remap_range(struct file *file_in,
-                              loff_t pos_in,
-                              struct file *file_out,
-                              loff_t pos_out,
-                              loff_t len,
-                              unsigned int remap_flags);
+loff_t ocfs2_reflink_remap_range(struct file *file_in,
+                                 loff_t pos_in,
+                                 struct file *file_out,
+                                 loff_t pos_out,
+                                 loff_t len,
+                                 unsigned int remap_flags);
 
 #endif /* OCFS2_REFCOUNTTREE_H */