From ba998f347b374291208f264661be30426c149939 Mon Sep 17 00:00:00 2001 From: Jiaju Zhang Date: Wed, 28 Jul 2010 13:21:06 +0800 Subject: Fix the nested PR lock calling issue in ACL commit 845b6cf34150100deb5f58c8a37a372b111f2918 upstream. Hi, Thanks a lot for all the review and comments so far;) I'd like to send the improved (V4) version of this patch. This patch fixes a deadlock in OCFS2 ACL. We found this bug in OCFS2 and Samba integration using scenario, the symptom is several smbd processes will be hung under heavy workload. Finally we found out it is the nested PR lock calling that leads to this deadlock: node1 node2 gr PR | V PR(EX)---> BAST:OCFS2_LOCK_BLOCKED | V rq PR | V wait=1 After requesting the 2nd PR lock, the process "smbd" went into D state. It can only be woken up when the 1st PR lock's RO holder equals zero. There should be an ocfs2_inode_unlock in the calling path later on, which can decrement the RO holder. But since it has been in uninterruptible sleep, the unlock function has no chance to be called. The related stack trace is: smbd D ffff8800013d0600 0 9522 5608 0x00000000 ffff88002ca7fb18 0000000000000282 ffff88002f964500 ffff88002ca7fa98 ffff8800013d0600 ffff88002ca7fae0 ffff88002f964340 ffff88002f964340 ffff88002ca7ffd8 ffff88002ca7ffd8 ffff88002f964340 ffff88002f964340 Call Trace: [] schedule_timeout+0x175/0x210 [] wait_for_common+0xf0/0x210 [] __ocfs2_cluster_lock+0x3b9/0xa90 [ocfs2] [] ocfs2_inode_lock_full_nested+0x255/0xdb0 [ocfs2] [] ocfs2_get_acl+0x69/0x120 [ocfs2] [] ocfs2_check_acl+0x28/0x80 [ocfs2] [] acl_permission_check+0x57/0xb0 [] generic_permission+0x1d/0xc0 [] ocfs2_permission+0x10a/0x1d0 [ocfs2] [] inode_permission+0x45/0x100 [] sys_chdir+0x53/0x90 [] system_call_fastpath+0x16/0x1b [<00007f34a4ef6927>] 0x7f34a4ef6927 For details, please see: https://bugzilla.novell.com/show_bug.cgi?id=614332 and http://oss.oracle.com/bugzilla/show_bug.cgi?id=1278 Signed-off-by: Jiaju Zhang Acked-by: Mark Fasheh Signed-off-by: Joel Becker Signed-off-by: Greg Kroah-Hartman --- fs/ocfs2/acl.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) (limited to 'fs') diff --git a/fs/ocfs2/acl.c b/fs/ocfs2/acl.c index ff43e875874..c8288df5712 100644 --- a/fs/ocfs2/acl.c +++ b/fs/ocfs2/acl.c @@ -293,12 +293,30 @@ static int ocfs2_set_acl(handle_t *handle, int ocfs2_check_acl(struct inode *inode, int mask) { - struct posix_acl *acl = ocfs2_get_acl(inode, ACL_TYPE_ACCESS); + struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); + struct buffer_head *di_bh = NULL; + struct posix_acl *acl; + int ret = -EAGAIN; - if (IS_ERR(acl)) + if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL)) + return ret; + + ret = ocfs2_read_inode_block(inode, &di_bh); + if (ret < 0) { + mlog_errno(ret); + return ret; + } + + acl = ocfs2_get_acl_nolock(inode, ACL_TYPE_ACCESS, di_bh); + + brelse(di_bh); + + if (IS_ERR(acl)) { + mlog_errno(PTR_ERR(acl)); return PTR_ERR(acl); + } if (acl) { - int ret = posix_acl_permission(inode, acl, mask); + ret = posix_acl_permission(inode, acl, mask); posix_acl_release(acl); return ret; } -- cgit v1.2.3-18-g5258