block_dump: remove block_dump feature when dirting inode

hulk inclusion
category: bugfix
bugzilla: 48166
CVE: NA
---------------------------

block_dump is an old debugging interface, one of it's functions is used
to dump who write which file on disk. If block_dump is enabled, we can
turn on debug log level and gather information about write process name
file name from kmsg. It is done by block_dump___mark_inode_dirty() to
print kernel message directly when marking inode dirty, so it can
trigger log storm easily.

After tracepoints has been introduced into the kernel, we got
trace_writeback_mark_inode_dirty() in __mark_inode_dirty(), which is a
better replacement of block_dump___mark_inode_dirty(). The only downside
is that it only trace the inode number and not a file name, but it may
not a big deal because the original dumped file name in block_dump is
not accurate in some cases, and we can still find it through the inode
number and device id. So this patch delete the block_dump feature.
Signed-off-by: Nzhangyi (F) <yi.zhang@huawei.com>
Reviewed-by: NYe bin <yebin10@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>

fs/fs-writeback.c

@@ -2117,28 +2117,6 @@ int dirtytime_interval_handler(struct ctl_table *table, int write,
 	return ret;
 }
 
-static noinline void block_dump___mark_inode_dirty(struct inode *inode)
-{
-	if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) {
-		struct dentry *dentry;
-		const char *name = "?";
-
-		dentry = d_find_alias(inode);
-		if (dentry) {
-			spin_lock(&dentry->d_lock);
-			name = (const char *) dentry->d_name.name;
-		}
-		printk(KERN_DEBUG
-		       "%s(%d): dirtied inode %lu (%s) on %s\n",
-		       current->comm, task_pid_nr(current), inode->i_ino,
-		       name, inode->i_sb->s_id);
-		if (dentry) {
-			spin_unlock(&dentry->d_lock);
-			dput(dentry);
-		}
-	}
-}
-
 /**
  * __mark_inode_dirty -	internal function
  *
@@ -2198,9 +2176,6 @@ void __mark_inode_dirty(struct inode *inode, int flags)
 	    (dirtytime && (inode->i_state & I_DIRTY_INODE)))
 		return;
 
-	if (unlikely(block_dump))
-		block_dump___mark_inode_dirty(inode);
-
 	spin_lock(&inode->i_lock);
 	if (dirtytime && (inode->i_state & I_DIRTY_INODE))
 		goto out_unlock_inode;