GFS2: filesystem hang caused by incorrect lock order
This patch fixes a deadlock in GFS2 where two processes are trying
to reclaim an unlinked dinode:
One holds the inode glock and calls gfs2_lookup_by_inum trying to look
up the inode, which it can't, due to I_FREEING. The other has set
I_FREEING from vfs and is at the beginning of gfs2_delete_inode
waiting for the glock, which is held by the first. The solution is to
add a new non_block parameter to the gfs2_iget function that causes it
to return -ENOENT if the inode is being freed.
Signed-off-by: Bob Peterson <[email protected]>
Signed-off-by: Steven Whitehouse <[email protected]>
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index cf930cd..6fcae84 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -945,7 +945,7 @@
/* rgblk_search can return a block < goal, so we need to
keep it marching forward. */
no_addr = block + rgd->rd_data0;
- goal++;
+ goal = max(block + 1, goal + 1);
if (*last_unlinked != NO_BLOCK && no_addr <= *last_unlinked)
continue;
if (no_addr == skip)
@@ -971,7 +971,7 @@
found++;
/* Limit reclaim to sensible number of tasks */
- if (found > 2*NR_CPUS)
+ if (found > NR_CPUS)
return;
}
