From: Yu Kuai <yukuai3@xxxxxxxxxx>
block_device_ejected() is added by commit bdfe0cbd746a ("Revert
"ext4: remove block_device_ejected"") in 2015. At that time 'bdi->wb'
is destroyed synchronized from del_gendisk(), hence if ext4 is still
mounted, and then mark_buffer_dirty() will reference destroyed 'wb'.
However, such problem doesn't exist anymore:
- commit d03f6cdc1fc4 ("block: Dynamically allocate and refcount
backing_dev_info") switch bdi to use refcounting;
- commit 13eec2363ef0 ("fs: Get proper reference for s_bdi"), will grab
additional reference of bdi while mounting, so that 'bdi->wb' will not
be destroyed until generic_shutdown_super().
Hence remove this dead function block_device_ejected().
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
fs/ext4/super.c | 18 ------------------
1 file changed, 18 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 3fce1b80c419..cf4666b04d2e 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -492,22 +492,6 @@ static void ext4_maybe_update_superblock(struct super_block *sb)
schedule_work(&EXT4_SB(sb)->s_sb_upd_work);
}
-/*
- * The del_gendisk() function uninitializes the disk-specific data
- * structures, including the bdi structure, without telling anyone
- * else. Once this happens, any attempt to call mark_buffer_dirty()
- * (for example, by ext4_commit_super), will cause a kernel OOPS.
- * This is a kludge to prevent these oops until we can put in a proper
- * hook in del_gendisk() to inform the VFS and file system layers.
- */
-static int block_device_ejected(struct super_block *sb)
-{
- struct inode *bd_inode = sb->s_bdev->bd_inode;
- struct backing_dev_info *bdi = inode_to_bdi(bd_inode);
-
- return bdi->dev == NULL;
-}
-
static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
{
struct super_block *sb = journal->j_private;
@@ -6168,8 +6152,6 @@ static int ext4_commit_super(struct super_block *sb)
if (!sbh)
return -EINVAL;
- if (block_device_ejected(sb))
- return -ENODEV;
ext4_update_super(sb);
--
2.39.2
