nilfs2: remove wbc->for_reclaim handling

Since commit 013a070 ("nilfs2: convert metadata aops from writepage
to writepages"), nilfs_mdt_write_folio can't be called from reclaim
context any more.  Remove the code keyed of the wbc->for_reclaim flag,
which is now only set for writing out swap or shmem pages inside the swap
code, but never passed to file systems.

Link: https://lkml.kernel.org/r/20250508054938.15894-7-hch@lst.de
Link: https://lkml.kernel.org/r/20250516123417.6779-1-konishi.ryusuke@gmail.com
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Christoph Hellwig

fs/nilfs2/mdt.c

@@ -422,8 +422,6 @@ static int nilfs_mdt_write_folio(struct folio *folio,
 
 	if (wbc->sync_mode == WB_SYNC_ALL)
 		err = nilfs_construct_segment(sb);
-	else if (wbc->for_reclaim)
-		nilfs_flush_segment(sb, inode->i_ino);
 
 	return err;
 }

fs/nilfs2/segment.c

@@ -2221,22 +2221,6 @@ static void nilfs_segctor_do_flush(struct nilfs_sc_info *sci, int bn)
 	spin_unlock(&sci->sc_state_lock);
 }
 
-/**
- * nilfs_flush_segment - trigger a segment construction for resource control
- * @sb: super block
- * @ino: inode number of the file to be flushed out.
- */
-void nilfs_flush_segment(struct super_block *sb, ino_t ino)
-{
-	struct the_nilfs *nilfs = sb->s_fs_info;
-	struct nilfs_sc_info *sci = nilfs->ns_writer;
-
-	if (!sci || nilfs_doing_construction())
-		return;
-	nilfs_segctor_do_flush(sci, NILFS_MDT_INODE(sb, ino) ? ino : 0);
-					/* assign bit 0 to data files */
-}
-
 struct nilfs_segctor_wait_request {
 	wait_queue_entry_t	wq;
 	__u32		seq;

fs/nilfs2/segment.h

@@ -226,7 +226,6 @@ extern void nilfs_relax_pressure_in_lock(struct super_block *);
 extern int nilfs_construct_segment(struct super_block *);
 extern int nilfs_construct_dsync_segment(struct super_block *, struct inode *,
 					 loff_t, loff_t);
-extern void nilfs_flush_segment(struct super_block *, ino_t);
 extern int nilfs_clean_segments(struct super_block *, struct nilfs_argv *,
 				void **);