summary refs log tree commit diff
path: root/fs/xfs/xfs_fsops.c
diff options
context:
space:
mode:
authorChristoph Hellwig <hch@infradead.org>2009-07-18 18:14:53 -0400
committerFelix Blyakher <felixb@sgi.com>2009-08-12 01:06:51 -0500
commit0cc6eee130b0c062feec8446d9cecdb17d2cfad3 (patch)
tree488cbdb1fb8623285c4fb7c3a913516d7b7905d2 /fs/xfs/xfs_fsops.c
parentc8a4051c3731b6db224482218cfd535ab9393ff8 (diff)
downloadlinux-0cc6eee130b0c062feec8446d9cecdb17d2cfad3.tar.gz
xfs: avoid memory allocation under m_peraglock in growfs code
Allocate the memory for the larger m_perag array before taking the
per-AG lock as the per-AG lock can be taken under the i_lock which
can be taken from reclaim context.

Reported by the new reclaim context tracing in lockdep.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Felix Blyakher <felixb@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_fsops.c')
-rw-r--r--fs/xfs/xfs_fsops.c20
1 files changed, 14 insertions, 6 deletions
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index cbd451bb4848..2d0b3e1da9e6 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -167,17 +167,25 @@ xfs_growfs_data_private(
 	new = nb - mp->m_sb.sb_dblocks;
 	oagcount = mp->m_sb.sb_agcount;
 	if (nagcount > oagcount) {
+		void *new_perag, *old_perag;
+
 		xfs_filestream_flush(mp);
+
+		new_perag = kmem_zalloc(sizeof(xfs_perag_t) * nagcount,
+					KM_MAYFAIL);
+		if (!new_perag)
+			return XFS_ERROR(ENOMEM);
+
 		down_write(&mp->m_peraglock);
-		mp->m_perag = kmem_realloc(mp->m_perag,
-			sizeof(xfs_perag_t) * nagcount,
-			sizeof(xfs_perag_t) * oagcount,
-			KM_SLEEP);
-		memset(&mp->m_perag[oagcount], 0,
-			(nagcount - oagcount) * sizeof(xfs_perag_t));
+		memcpy(new_perag, mp->m_perag, sizeof(xfs_perag_t) * oagcount);
+		old_perag = mp->m_perag;
+		mp->m_perag = new_perag;
+
 		mp->m_flags |= XFS_MOUNT_32BITINODES;
 		nagimax = xfs_initialize_perag(mp, nagcount);
 		up_write(&mp->m_peraglock);
+
+		kmem_free(old_perag);
 	}
 	tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFS);
 	tp->t_flags |= XFS_TRANS_RESERVE;