[PATCH RFC v2 08/13] minix: don't read the inode block in minix_sync_inode_metadata()

[Christian Brauner <brauner@kernel.org>]

minix_sync_inode_metadata() looks the inode block up with
minix_V1_raw_inode() or minix_V2_raw_inode() which read it from disk if
it isn't cached. But a block that isn't cached is neither dirty nor
under writeback, so there's nothing to write or to wait for.

That read is also something we can't afford once inode eviction calls
->sync_inode_metadata() from reclaim. So look the block up with
sb_find_get_block_nonatomic() instead.

Cc: stable@vger.kernel.org # v7.3
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
---
 fs/minix/inode.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/minix/inode.c b/fs/minix/inode.c
index 670179173645..756bef4dc832 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -702,24 +702,24 @@ static int minix_sync_inode_metadata(struct inode *inode,
 {
 	int err = 0;
 	struct buffer_head *bh;
-	void *raw_inode;
+	int block;
 
-	if (INODE_VERSION(inode) == MINIX_V1)
-		raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
-	else
-		raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
-	if (!raw_inode)
+	block = minix_inode_block(inode->i_sb, inode->i_ino);
+	if (!block)
 		return -EIO;
 	err = mmb_sync(&minix_i(inode)->i_metadata_bhs);
 	if (err)
-		goto out;
+		return err;
+	/* A block that isn't cached is neither dirty nor under writeback. */
+	bh = sb_find_get_block_nonatomic(inode->i_sb, block);
+	if (!bh)
+		return 0;
 	sync_dirty_buffer(bh);
 	if (buffer_write_io_error(bh)) {
 		printk("IO error syncing minix inode [%s:%08llx]\n",
 			inode->i_sb->s_id, inode->i_ino);
 		err = -EIO;
 	}
-out:
 	brelse(bh);
 	return err;
 }

-- 
2.53.0