ocfs2: Provide ocfs2_xa_fill_value_buf() for external value processing

We use the ocfs2_xattr_value_buf structure to manage external values.
It lets the value tree code do its work regardless of the containing
storage.  ocfs2_xa_fill_value_buf() initializes a value buf from an
ocfs2_xa_loc entry.

Signed-off-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 59 insertions, 0 deletions

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index 6d362e2d3960..e0d0fa23a19b 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -172,6 +172,13 @@ struct ocfs2_xa_loc_operations {
 
         /* Add name+value storage to an entry */
         void (*xlo_add_namevalue)(struct ocfs2_xa_loc *loc, int size);
+
+        /*
+         * Initialize the value buf's access and bh fields for this entry.
+         * ocfs2_xa_fill_value_buf() will handle the xv pointer.
+         */
+        void (*xlo_fill_value_buf)(struct ocfs2_xa_loc *loc,
+                                   struct ocfs2_xattr_value_buf *vb);
 };
 
 /*
@@ -1605,6 +1612,23 @@ static void ocfs2_xa_add_namevalue(struct ocfs2_xa_loc *loc,
         memcpy(nameval_buf, xi->xi_name, xi->xi_name_len);
 }
 
+static void ocfs2_xa_fill_value_buf(struct ocfs2_xa_loc *loc,
+                                    struct ocfs2_xattr_value_buf *vb)
+{
+        int nameval_offset = le16_to_cpu(loc->xl_entry->xe_name_offset);
+        int name_size = OCFS2_XATTR_SIZE(loc->xl_entry->xe_name_len);
+
+        /* Value bufs are for value trees */
+        BUG_ON(namevalue_size_xe(loc->xl_entry) !=
+               (name_size + OCFS2_XATTR_ROOT_SIZE));
+
+        loc->xl_ops->xlo_fill_value_buf(loc, vb);
+        vb->vb_xv =
+                (struct ocfs2_xattr_value_root *)ocfs2_xa_offset_pointer(loc,
+                                                        nameval_offset +
+                                                        name_size);
+}
+
 static void *ocfs2_xa_block_offset_pointer(struct ocfs2_xa_loc *loc,
                                            int offset)
 {
@@ -1712,6 +1736,20 @@ static void ocfs2_xa_block_add_namevalue(struct ocfs2_xa_loc *loc, int size)
         loc->xl_entry->xe_name_offset = cpu_to_le16(free_start - size);
 }
 
+static void ocfs2_xa_block_fill_value_buf(struct ocfs2_xa_loc *loc,
+                                          struct ocfs2_xattr_value_buf *vb)
+{
+        struct buffer_head *bh = loc->xl_storage;
+
+        if (loc->xl_size == (bh->b_size -
+                             offsetof(struct ocfs2_xattr_block,
+                                      xb_attrs.xb_header)))
+                vb->vb_access = ocfs2_journal_access_xb;
+        else
+                vb->vb_access = ocfs2_journal_access_di;
+        vb->vb_bh = bh;
+}
+
 /*
  * Operations for xattrs stored in blocks.  This includes inline inode
  * storage and unindexed ocfs2_xattr_blocks.
@@ -1724,6 +1762,7 @@ static const struct ocfs2_xa_loc_operations ocfs2_xa_block_loc_ops = {
         .xlo_wipe_namevalue     = ocfs2_xa_block_wipe_namevalue,
         .xlo_add_entry          = ocfs2_xa_block_add_entry,
         .xlo_add_namevalue      = ocfs2_xa_block_add_namevalue,
+        .xlo_fill_value_buf     = ocfs2_xa_block_fill_value_buf,
 };
 
 static void *ocfs2_xa_bucket_offset_pointer(struct ocfs2_xa_loc *loc,
@@ -1869,6 +1908,25 @@ static void ocfs2_xa_bucket_add_namevalue(struct ocfs2_xa_loc *loc, int size)
 
 }
 
+static void ocfs2_xa_bucket_fill_value_buf(struct ocfs2_xa_loc *loc,
+                                           struct ocfs2_xattr_value_buf *vb)
+{
+        struct ocfs2_xattr_bucket *bucket = loc->xl_storage;
+        struct super_block *sb = bucket->bu_inode->i_sb;
+        int nameval_offset = le16_to_cpu(loc->xl_entry->xe_name_offset);
+        int size = namevalue_size_xe(loc->xl_entry);
+        int block_offset = nameval_offset >> sb->s_blocksize_bits;
+
+        /* Values are not allowed to straddle block boundaries */
+        BUG_ON(block_offset !=
+               ((nameval_offset + size - 1) >> sb->s_blocksize_bits));
+        /* We expect the bucket to be filled in */
+        BUG_ON(!bucket->bu_bhs[block_offset]);
+
+        vb->vb_access = ocfs2_journal_access;
+        vb->vb_bh = bucket->bu_bhs[block_offset];
+}
+
 /* Operations for xattrs stored in buckets. */
 static const struct ocfs2_xa_loc_operations ocfs2_xa_bucket_loc_ops = {
         .xlo_offset_pointer     = ocfs2_xa_bucket_offset_pointer,
@@ -1878,6 +1936,7 @@ static const struct ocfs2_xa_loc_operations ocfs2_xa_bucket_loc_ops = {
         .xlo_wipe_namevalue     = ocfs2_xa_bucket_wipe_namevalue,
         .xlo_add_entry          = ocfs2_xa_bucket_add_entry,
         .xlo_add_namevalue      = ocfs2_xa_bucket_add_namevalue,
+        .xlo_fill_value_buf     = ocfs2_xa_bucket_fill_value_buf,
 };
 
 static void ocfs2_xa_remove_entry(struct ocfs2_xa_loc *loc)