ext4: Fix lockdep warning (ba443916) · Commits · 戴 / test

We should not call ext4_mb_add_n_trim while holding alloc_semp. ============================================= [ INFO: possible recursive locking detected ] 2.6.29-rc4-git1-dirty #124 --------------------------------------------- ffsb/3116 is trying to acquire lock: (&meta_group_info[i]->alloc_sem){----}, at: [<ffffffff8035a6e8>] ext4_mb_load_buddy+0xd2/0x343 but task is already holding lock: (&meta_group_info[i]->alloc_sem){----}, at: [<ffffffff8035a6e8>] ext4_mb_load_buddy+0xd2/0x343 http://bugzilla.kernel.org/show_bug.cgi?id=12672 Signed-off-by:

Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by:

"Theodore Ts'o" <tytso@mit.edu>

fs/ext4/mballoc.c

+16 −13

Original line number	Diff line number	Diff line
		@@ -4476,23 +4476,26 @@ static int ext4_mb_release_context(struct ext4_allocation_context *ac)
		pa->pa_free -= ac->ac_b_ex.fe_len;
		pa->pa_len -= ac->ac_b_ex.fe_len;
		spin_unlock(&pa->pa_lock);
		}
		}
		if (ac->alloc_semp)
		up_read(ac->alloc_semp);
		if (pa) {
		/*
		* We want to add the pa to the right bucket.
		* Remove it from the list and while adding
		* make sure the list to which we are adding
		* doesn't grow big.
		* doesn't grow big. We need to release
		* alloc_semp before calling ext4_mb_add_n_trim()
		*/
		if (likely(pa->pa_free)) {
		if (pa->pa_linear && likely(pa->pa_free)) {
		spin_lock(pa->pa_obj_lock);
		list_del_rcu(&pa->pa_inode_list);
		spin_unlock(pa->pa_obj_lock);
		ext4_mb_add_n_trim(ac);
		}
		}
		ext4_mb_put_pa(ac, ac->ac_sb, pa);
		}
		if (ac->alloc_semp)
		up_read(ac->alloc_semp);
		if (ac->ac_bitmap_page)
		page_cache_release(ac->ac_bitmap_page);
		if (ac->ac_buddy_page)

Admin message