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Commit 4195f73d authored by Nick Piggin's avatar Nick Piggin Committed by Al Viro
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fs: block_dump missing dentry locking 



I think the block_dump output in __mark_inode_dirty is missing dentry locking.
Surely the i_dentry list can change any time, so we may not even *get* a
dentry there. If we do get one by chance, then it would appear to be able to
go away or get renamed at any time...

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 545b9fd3

fs/fs-writeback.c

+24 −17
Original line number Diff line number Diff line
@@ -64,6 +64,28 @@ static void writeback_release(struct backing_dev_info *bdi) 
	clear_bit(BDI_pdflush, &bdi->state);

}



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

 *	@inode: inode to mark
@@ -114,23 +136,8 @@ void __mark_inode_dirty(struct inode *inode, int flags) 
	if ((inode->i_state & flags) == flags)

		return;



	if (unlikely(block_dump)) {

		struct dentry *dentry = NULL;

		const char *name = "?";



		if (!list_empty(&inode->i_dentry)) {

			dentry = list_entry(inode->i_dentry.next,

					    struct dentry, d_alias);

			if (dentry && dentry->d_name.name)

				name = (const char *) dentry->d_name.name;

		}



		if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev"))

			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 (unlikely(block_dump))

		block_dump___mark_inode_dirty(inode);



	spin_lock(&inode_lock);

	if ((inode->i_state & flags) != flags) {