[PATCH 15/32] fs: Drop osync_buffers_list()

[Jan Kara <jack@suse.cz>]

The function only waits for already locked buffers in the list of
metadata bhs. fsync_buffers_list() has just waited for all outstanding
IO on buffers so this isn't adding anything useful. Comment in front of
fsync_buffers_list() mentions concerns about buffers being moved out
from tmp list back to mappings i_private_list but these days
mark_buffer_dirty_inode() doesn't touch inodes with b_assoc_map set so
that cannot happen. Just delete the stale code.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/buffer.c | 43 ++-----------------------------------------
 1 file changed, 2 insertions(+), 41 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index c85ccfb1a4ec..1c0e7c81a38b 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -526,41 +526,6 @@ int inode_has_buffers(struct inode *inode)
 }
 EXPORT_SYMBOL_GPL(inode_has_buffers);
 
-/*
- * osync is designed to support O_SYNC io.  It waits synchronously for
- * all already-submitted IO to complete, but does not queue any new
- * writes to the disk.
- *
- * To do O_SYNC writes, just queue the buffer writes with write_dirty_buffer
- * as you dirty the buffers, and then use osync_inode_buffers to wait for
- * completion.  Any other dirty buffers which are not yet queued for
- * write will not be flushed to disk by the osync.
- */
-static int osync_buffers_list(spinlock_t *lock, struct list_head *list)
-{
-	struct buffer_head *bh;
-	struct list_head *p;
-	int err = 0;
-
-	spin_lock(lock);
-repeat:
-	list_for_each_prev(p, list) {
-		bh = BH_ENTRY(p);
-		if (buffer_locked(bh)) {
-			get_bh(bh);
-			spin_unlock(lock);
-			wait_on_buffer(bh);
-			if (!buffer_uptodate(bh))
-				err = -EIO;
-			brelse(bh);
-			spin_lock(lock);
-			goto repeat;
-		}
-	}
-	spin_unlock(lock);
-	return err;
-}
-
 /**
  * sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers
  * @mapping: the mapping which wants those buffers written
@@ -777,7 +742,7 @@ static int fsync_buffers_list(spinlock_t *lock, struct list_head *list)
 {
 	struct buffer_head *bh;
 	struct address_space *mapping;
-	int err = 0, err2;
+	int err = 0;
 	struct blk_plug plug;
 	LIST_HEAD(tmp);
 
@@ -844,11 +809,7 @@ static int fsync_buffers_list(spinlock_t *lock, struct list_head *list)
 	}
 	
 	spin_unlock(lock);
-	err2 = osync_buffers_list(lock, list);
-	if (err)
-		return err;
-	else
-		return err2;
+	return err;
 }
 
 /*
-- 
2.51.0