[PATCH 30/32] vfs: Drop mapping_metadata_bhs from address space

[Jan Kara <jack@suse.cz>]

Nobody uses mapping_metadata_bhs in struct address_space anymore. Just
remove it.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/buffer.c        | 16 ++++++++++------
 fs/inode.c         |  2 --
 include/linux/fs.h |  1 -
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 096a8d9e3280..02176e0acfe1 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -501,9 +501,13 @@ EXPORT_SYMBOL(mmb_init);
 
 static struct mapping_metadata_bhs *inode_get_metadata_bhs(struct inode *inode)
 {
+	/*
+	 * We can get called for various half-initialized or bad inodes so
+	 * verify .get_metadata_bhs callback exists.
+	 */
 	if (inode->i_op->get_metadata_bhs)
 		return inode->i_op->get_metadata_bhs(inode);
-	return &inode->i_mapping->i_metadata_bhs;
+	return NULL;
 }
 
 static void __remove_assoc_queue(struct mapping_metadata_bhs *mmb,
@@ -544,7 +548,7 @@ static void remove_assoc_queue(struct buffer_head *bh)
 
 bool mmb_has_buffers(struct mapping_metadata_bhs *mmb)
 {
-	return !list_empty(&mmb->list);
+	return mmb && !list_empty(&mmb->list);
 }
 EXPORT_SYMBOL_GPL(mmb_has_buffers);
 
@@ -552,10 +556,10 @@ EXPORT_SYMBOL_GPL(mmb_has_buffers);
  * sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers
  * @mapping: the mapping which wants those buffers written
  *
- * Starts I/O against the buffers at mapping->i_metadata_bhs and waits upon
- * that I/O. Basically, this is a convenience function for fsync().  @mapping
- * is a file or directory which needs those buffers to be written for a
- * successful fsync().
+ * Starts I/O against the buffers tracked in mapping_metadata_bhs for the
+ * mapping and waits upon that I/O. Basically, this is a convenience function
+ * for fsync().  @mapping is a file or directory which needs those buffers to
+ * be written for a successful fsync().
  *
  * We have conflicting pressures: we want to make sure that all
  * initially dirty buffers get waited on, but that any subsequently
diff --git a/fs/inode.c b/fs/inode.c
index 393f586d050a..d5774e627a9c 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -483,8 +483,6 @@ static void __address_space_init_once(struct address_space *mapping)
 	init_rwsem(&mapping->i_mmap_rwsem);
 	INIT_LIST_HEAD(&mapping->i_private_list);
 	spin_lock_init(&mapping->i_private_lock);
-	spin_lock_init(&mapping->i_metadata_bhs.lock);
-	INIT_LIST_HEAD(&mapping->i_metadata_bhs.list);
 	mapping->i_mmap = RB_ROOT_CACHED;
 }
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b4d9be1fefa4..1611d8ce4b66 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -490,7 +490,6 @@ struct address_space {
 	errseq_t		wb_err;
 	spinlock_t		i_private_lock;
 	struct list_head	i_private_list;
-	struct mapping_metadata_bhs i_metadata_bhs;
 	struct rw_semaphore	i_mmap_rwsem;
 } __attribute__((aligned(sizeof(long)))) __randomize_layout;
 	/*
-- 
2.51.0