nilfs2: get rid of back pointer to writable sb instance

Nilfs object holds a back pointer to a writable super block instance
in nilfs->ns_writer, and this became eliminable since sb is now made
per device and all inodes have a valid pointer to it.

This deletes the ns_writer pointer and a reader/writer semaphore
protecting it.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 2 insertions, 31 deletions

diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c
index 32695f3c4b9a..0a2ccfc0d6f9 100644
--- a/fs/nilfs2/mdt.c
+++ b/fs/nilfs2/mdt.c
@@ -78,25 +78,11 @@ static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
                                                      struct buffer_head *,
                                                      void *))
 {
-        struct the_nilfs *nilfs = NILFS_I_NILFS(inode);
         struct super_block *sb = inode->i_sb;
         struct nilfs_transaction_info ti;
         struct buffer_head *bh;
         int err;
 
-        if (!sb) {
-                /*
-                 * Make sure this function is not called from any
-                 * read-only context.
-                 */
-                if (!nilfs->ns_writer) {
-                        WARN_ON(1);
-                        err = -EROFS;
-                        goto out;
-                }
-                sb = nilfs->ns_writer->s_super;
-        }
-
         nilfs_transaction_begin(sb, &ti, 0);
 
         err = -ENOMEM;
@@ -112,7 +98,7 @@ static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
         if (buffer_uptodate(bh))
                 goto failed_bh;
 
-        bh->b_bdev = nilfs->ns_bdev;
+        bh->b_bdev = sb->s_bdev;
         err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
         if (likely(!err)) {
                 get_bh(bh);
@@ -129,7 +115,7 @@ static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
                 err = nilfs_transaction_commit(sb);
         else
                 nilfs_transaction_abort(sb);
- out:
+
         return err;
 }
 
@@ -398,8 +384,6 @@ nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
 {
         struct inode *inode;
         struct super_block *sb;
-        struct the_nilfs *nilfs;
-        struct nilfs_sb_info *writer = NULL;
         int err = 0;
 
         redirty_page_for_writepage(wbc, page);
@@ -410,25 +394,12 @@ nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
                 return 0;
 
         sb = inode->i_sb;
-        nilfs = NILFS_SB(sb)->s_nilfs;
-
-        if (!sb) {
-                down_read(&nilfs->ns_writer_sem);
-                writer = nilfs->ns_writer;
-                if (!writer) {
-                        up_read(&nilfs->ns_writer_sem);
-                        return -EROFS;
-                }
-                sb = writer->s_super;
-        }
 
         if (wbc->sync_mode == WB_SYNC_ALL)
                 err = nilfs_construct_segment(sb);
         else if (wbc->for_reclaim)
                 nilfs_flush_segment(sb, inode->i_ino);
 
-        if (writer)
-                up_read(&nilfs->ns_writer_sem);
         return err;
 }