Commit 73597e3e authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: ensure dentry consistency when the orphanage adopts a file 



When the orphanage adopts a file, that file becomes a child of the
orphanage.  The dentry cache may have entries for the orphanage
directory and the name we've chosen, so (1) make sure we abort if the
dcache has a positive entry because something's not right; and (2)
invalidate and purge negative dentries if the adoption goes through.

Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent e6c9e75f

fs/xfs/scrub/orphanage.c

+91 −0
Original line number Diff line number Diff line
@@ -418,6 +418,90 @@ xrep_adoption_compute_name( 
	return 0;

}



/*

 * Make sure the dcache does not have a positive dentry for the name we've

 * chosen.  The caller should have checked with the ondisk directory, so any

 * discrepancy is a sign that something is seriously wrong.

 */

static int

xrep_adoption_check_dcache(

	struct xrep_adoption	*adopt)

{

	struct qstr		qname = QSTR_INIT(adopt->xname->name,

						  adopt->xname->len);

	struct dentry		*d_orphanage, *d_child;

	int			error = 0;



	d_orphanage = d_find_alias(VFS_I(adopt->sc->orphanage));

	if (!d_orphanage)

		return 0;



	d_child = d_hash_and_lookup(d_orphanage, &qname);

	if (d_child) {

		trace_xrep_adoption_check_child(adopt->sc->mp, d_child);



		if (d_is_positive(d_child)) {

			ASSERT(d_is_negative(d_child));

			error = -EFSCORRUPTED;

		}



		dput(d_child);

	}



	dput(d_orphanage);

	if (error)

		return error;



	/*

	 * Do we need to update d_parent of the dentry for the file being

	 * repaired?  There shouldn't be a hashed dentry with a parent since

	 * the file had nonzero nlink but wasn't connected to any parent dir.

	 */

	d_child = d_find_alias(VFS_I(adopt->sc->ip));

	if (!d_child)

		return 0;



	trace_xrep_adoption_check_alias(adopt->sc->mp, d_child);



	if (d_child->d_parent && !d_unhashed(d_child)) {

		ASSERT(d_child->d_parent == NULL || d_unhashed(d_child));

		error = -EFSCORRUPTED;

	}



	dput(d_child);

	return error;

}



/*

 * Remove all negative dentries from the dcache.  There should not be any

 * positive entries, since we've maintained our lock on the orphanage

 * directory.

 */

static void

xrep_adoption_zap_dcache(

	struct xrep_adoption	*adopt)

{

	struct qstr		qname = QSTR_INIT(adopt->xname->name,

						  adopt->xname->len);

	struct dentry		*d_orphanage, *d_child;



	d_orphanage = d_find_alias(VFS_I(adopt->sc->orphanage));

	if (!d_orphanage)

		return;



	d_child = d_hash_and_lookup(d_orphanage, &qname);

	while (d_child != NULL) {

		trace_xrep_adoption_invalidate_child(adopt->sc->mp, d_child);



		ASSERT(d_is_negative(d_child));

		d_invalidate(d_child);

		dput(d_child);

		d_child = d_lookup(d_orphanage, &qname);

	}



	dput(d_orphanage);

}



/*

 * Move the current file to the orphanage under the computed name.

 *
@@ -435,6 +519,10 @@ xrep_adoption_move( 
	trace_xrep_adoption_reparent(sc->orphanage, adopt->xname,

			sc->ip->i_ino);



	error = xrep_adoption_check_dcache(adopt);

	if (error)

		return error;



	/* Create the new name in the orphanage. */

	error = xfs_dir_createname(sc->tp, sc->orphanage, adopt->xname,

			sc->ip->i_ino, adopt->orphanage_blkres);
@@ -465,6 +553,9 @@ xrep_adoption_move( 
	 * recorded in the log.

	 */

	xfs_dir_update_hook(sc->orphanage, sc->ip, 1, adopt->xname);



	/* Remove negative dentries from the lost+found's dcache */

	xrep_adoption_zap_dcache(adopt);

	return 0;

}

fs/xfs/scrub/trace.h

+42 −0
Original line number Diff line number Diff line
@@ -2669,6 +2669,48 @@ TRACE_EVENT(xrep_nlinks_set_record, 
		  __entry->children)

);



DECLARE_EVENT_CLASS(xrep_dentry_class,

	TP_PROTO(struct xfs_mount *mp, const struct dentry *dentry),

	TP_ARGS(mp, dentry),

	TP_STRUCT__entry(

		__field(dev_t, dev)

		__field(unsigned int, flags)

		__field(unsigned long, ino)

		__field(bool, positive)

		__field(unsigned long, parent_ino)

		__field(unsigned int, namelen)

		__dynamic_array(char, name, dentry->d_name.len)

	),

	TP_fast_assign(

		__entry->dev = mp->m_super->s_dev;

		__entry->flags = dentry->d_flags;

		__entry->positive = d_is_positive(dentry);

		if (dentry->d_parent && d_inode(dentry->d_parent))

			__entry->parent_ino = d_inode(dentry->d_parent)->i_ino;

		else

			__entry->parent_ino = -1UL;

		__entry->ino = d_inode(dentry) ? d_inode(dentry)->i_ino : 0;

		__entry->namelen = dentry->d_name.len;

		memcpy(__get_str(name), dentry->d_name.name, dentry->d_name.len);

	),

	TP_printk("dev %d:%d flags 0x%x positive? %d parent_ino 0x%lx ino 0x%lx name '%.*s'",

		  MAJOR(__entry->dev), MINOR(__entry->dev),

		  __entry->flags,

		  __entry->positive,

		  __entry->parent_ino,

		  __entry->ino,

		  __entry->namelen,

		  __get_str(name))

);

#define DEFINE_REPAIR_DENTRY_EVENT(name) \

DEFINE_EVENT(xrep_dentry_class, name, \

	TP_PROTO(struct xfs_mount *mp, const struct dentry *dentry), \

	TP_ARGS(mp, dentry))

DEFINE_REPAIR_DENTRY_EVENT(xrep_adoption_check_child);

DEFINE_REPAIR_DENTRY_EVENT(xrep_adoption_check_alias);

DEFINE_REPAIR_DENTRY_EVENT(xrep_adoption_check_dentry);

DEFINE_REPAIR_DENTRY_EVENT(xrep_adoption_invalidate_child);



#endif /* IS_ENABLED(CONFIG_XFS_ONLINE_REPAIR) */



#endif /* _TRACE_XFS_SCRUB_TRACE_H */