From 1247017f43a93eae3d64b7c25f3637dc545f5a47 Mon Sep 17 00:00:00 2001 From: jiangyiwen Date: Thu, 14 Jan 2016 15:17:33 -0800 Subject: [PATCH] ocfs2: fix slot overwritten if storage link down during mount The following case will lead to slot overwritten. N1 N2 mount ocfs2 volume, find and allocate slot 0, then set osb->slot_num to 0, begin to write slot info to disk mount ocfs2 volume, wait for super lock write block fail because of storage link down, unlock super lock got super lock and also allocate slot 0 then unlock super lock mount fail and then dismount, since osb->slot_num is 0, try to put invalid slot to disk. And it will succeed if storage link restores. N2 slot info is now overwritten Once another node say N3 mount, it will find and allocate slot 0 again, which will lead to mount hung because journal has already been locked by N2. so when write slot info failed, invalidate slot in advance to avoid overwrite slot. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Yiwen Jiang Reviewed-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/slot_map.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c index 47bba1be2a51..1e09592148ad 100644 --- a/fs/ocfs2/slot_map.c +++ b/fs/ocfs2/slot_map.c @@ -502,8 +502,17 @@ int ocfs2_find_slot(struct ocfs2_super *osb) trace_ocfs2_find_slot(osb->slot_num); status = ocfs2_update_disk_slot(osb, si, osb->slot_num); - if (status < 0) + if (status < 0) { mlog_errno(status); + /* + * if write block failed, invalidate slot to avoid overwrite + * slot during dismount in case another node rightly has mounted + */ + spin_lock(&osb->osb_lock); + ocfs2_invalidate_slot(si, osb->slot_num); + osb->slot_num = OCFS2_INVALID_SLOT; + spin_unlock(&osb->osb_lock); + } bail: return status;