Commit b313a5f1 authored Sep 24, 2013 by Dave Chinner Committed by Ben Myers Sep 24, 2013

xfs: asserting lock not held during freeing not valid



When we free an inode, we do so via RCU. As an RCU lookup can occur
at any time before we free an inode, and that lookup takes the inode
flags lock, we cannot safely assert that the flags lock is not held
just before marking it dead and running call_rcu() to free the
inode.

We check on allocation of a new inode structre that the lock is not
held, so we still have protection against locks being leaked and
hence not correctly initialised when allocated out of the slab.
Hence just remove the assert...

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

parent 48852358

fs/xfs/xfs_icache.c

+4 −5

Original line number	Diff line number	Diff line
		@@ -119,11 +119,6 @@ xfs_inode_free(
		ip->i_itemp = NULL;
		}

		/* asserts to verify all state is correct here */
		ASSERT(atomic_read(&ip->i_pincount) == 0);
		ASSERT(!spin_is_locked(&ip->i_flags_lock));
		ASSERT(!xfs_isiflocked(ip));

		/*
		* Because we use RCU freeing we need to ensure the inode always
		* appears to be reclaimed with an invalid inode number when in the
		@@ -135,6 +130,10 @@ xfs_inode_free(
		ip->i_ino = 0;
		spin_unlock(&ip->i_flags_lock);

		/* asserts to verify all state is correct here */
		ASSERT(atomic_read(&ip->i_pincount) == 0);
		ASSERT(!xfs_isiflocked(ip));

		call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
		}

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