[PATCH v2 6/8] fs/ext4: use sleeping version of __find_get_block()

[Luis Chamberlain <mcgrof@kernel.org>]

From: Davidlohr Bueso <dave@stgolabs.net>

Trivially introduce the wrapper and enable ext4_free_blocks() to use
it, which has a cond_resched to begin with. Convert to the new nonatomic
flavor to benefit from potential performance benefits and adapt in the
future vs migration such that semantics are kept.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 fs/ext4/inode.c             | 2 ++
 fs/ext4/mballoc.c           | 3 ++-
 include/linux/buffer_head.h | 6 ++++++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 1dc09ed5d403..b7acb5d3adcb 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -860,6 +860,8 @@ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
 		return sb_find_get_block(inode->i_sb, map.m_pblk);
 
 	/*
+	 * Potential TODO: use sb_find_get_block_nonatomic() instead.
+	 *
 	 * Since bh could introduce extra ref count such as referred by
 	 * journal_head etc. Try to avoid using __GFP_MOVABLE here
 	 * as it may fail the migration when journal_head remains.
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 0d523e9fb3d5..6f4265b21e19 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -6644,7 +6644,8 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
 		for (i = 0; i < count; i++) {
 			cond_resched();
 			if (is_metadata)
-				bh = sb_find_get_block(inode->i_sb, block + i);
+				bh = sb_find_get_block_nonatomic(inode->i_sb,
+								 block + i);
 			ext4_forget(handle, is_metadata, inode, bh, block + i);
 		}
 	}
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 2b5458517def..8db10ca288fc 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -399,6 +399,12 @@ sb_find_get_block(struct super_block *sb, sector_t block)
 	return __find_get_block(sb->s_bdev, block, sb->s_blocksize);
 }
 
+static inline struct buffer_head *
+sb_find_get_block_nonatomic(struct super_block *sb, sector_t block)
+{
+	return __find_get_block_nonatomic(sb->s_bdev, block, sb->s_blocksize);
+}
+
 static inline void
 map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block)
 {
-- 
2.47.2