f2fs: check the node block address of newly allocated nid (24928634) · Commits · 戴 / test

This patch adds a routine which checks the block address of newly allocated nid. If an nid has already allocated by other thread due to subtle data races, it will result in filesystem corruption. So, it needs to check whether its block address was already allocated or not in prior to nid allocation as the last chance. Signed-off-by:

Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/node.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -1573,6 +1573,8 @@ retry:

		/* We should not use stale free nids created by build_free_nids */
		if (nm_i->fcnt && !on_build_free_nids(nm_i)) {
		struct node_info ni;

		f2fs_bug_on(sbi, list_empty(&nm_i->free_nid_list));
		list_for_each_entry(i, &nm_i->free_nid_list, list)
		if (i->state == NID_NEW)
		@@ -1583,6 +1585,13 @@ retry:
		i->state = NID_ALLOC;
		nm_i->fcnt--;
		spin_unlock(&nm_i->free_nid_list_lock);

		/* check nid is allocated already */
		get_node_info(sbi, *nid, &ni);
		if (ni.blk_addr != NULL_ADDR) {
		alloc_nid_done(sbi, *nid);
		goto retry;
		}
		return true;
		}
		spin_unlock(&nm_i->free_nid_list_lock);

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