[PATCH 2/9] xfs: switch to NOFS allocation under i_lock in xfs_getbmap

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

xfs_getbmap allocates memory with i_lock held, but i_lock is taken in
reclaim context so all allocations under it must avoid recursions into
the filesystem.

Reported by the new reclaim context tracing in lockdep.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>

Index: linux-2.6/fs/xfs/xfs_bmap.c
===================================================================
--- linux-2.6.orig/fs/xfs/xfs_bmap.c    2009-07-10 13:05:24.808364312 +0200
+++ linux-2.6/fs/xfs/xfs_bmap.c 2009-07-10 13:16:00.830363579 +0200
@@ -6009,7 +6009,7 @@ xfs_getbmap(
         */
        error = ENOMEM;
        subnex = 16;
-       map = kmem_alloc(subnex * sizeof(*map), KM_MAYFAIL);
+       map = kmem_alloc(subnex * sizeof(*map), KM_MAYFAIL | KM_NOFS);
        if (!map)
                goto out_unlock_ilock;