* [Ocfs2-devel] [PATCH 1/2] ocfs2/lockdep: Move ip_xattr_sem out of ocfs2_xattr_get_nolock.
2010-09-07 5:29 [Ocfs2-devel] [PATCH 0/2] Fix 2 lockdep warning in ocfs2 Tao Ma
@ 2010-09-07 5:30 ` Tao Ma
2010-09-10 16:21 ` Joel Becker
2010-09-07 5:30 ` [Ocfs2-devel] [PATCH 2/2] ocfs2: Fix lockdep warning in reflink Tao Ma
1 sibling, 1 reply; 5+ messages in thread
From: Tao Ma @ 2010-09-07 5:30 UTC (permalink / raw)
To: ocfs2-devel
As the name shows, we shouldn't have any lock in
ocfs2_xattr_get_nolock. so lift ip_xattr_sem to the caller.
This should be safe for us since the only 2 callers are:
1. ocfs2_xattr_get which will lock the resources.
2. ocfs2_mknod which don't need this locking.
And this also resolves the following lockdep warning.
=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.35+ #5
-------------------------------------------------------
reflink/30027 is trying to acquire lock:
(&oi->ip_alloc_sem){+.+.+.}, at: [<ffffffffa0673b67>] ocfs2_reflink_ioctl+0x69a/0x1226 [ocfs2]
but task is already holding lock:
(&oi->ip_xattr_sem){++++..}, at: [<ffffffffa0673b58>] ocfs2_reflink_ioctl+0x68b/0x1226 [ocfs2]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&oi->ip_xattr_sem){++++..}:
[<ffffffff82064d6d>] __lock_acquire+0x79a/0x7f1
[<ffffffff82065a81>] lock_acquire+0xc6/0xed
[<ffffffff82339650>] down_read+0x34/0x47
[<ffffffffa0691cb8>] ocfs2_xattr_get_nolock+0xa0/0x4e6 [ocfs2]
[<ffffffffa069d64f>] ocfs2_get_acl_nolock+0x5c/0x132 [ocfs2]
[<ffffffffa069d9c7>] ocfs2_init_acl+0x60/0x243 [ocfs2]
[<ffffffffa066499d>] ocfs2_mknod+0xae8/0xfea [ocfs2]
[<ffffffffa0665041>] ocfs2_create+0x9d/0x105 [ocfs2]
[<ffffffff820e1c83>] vfs_create+0x9b/0xf4
[<ffffffff820e20bb>] do_last+0x2fd/0x5be
[<ffffffff820e31c0>] do_filp_open+0x1fb/0x572
[<ffffffff820d6cf6>] do_sys_open+0x5a/0xe7
[<ffffffff820d6dac>] sys_open+0x1b/0x1d
[<ffffffff8200296b>] system_call_fastpath+0x16/0x1b
-> #2 (jbd2_handle){+.+...}:
[<ffffffff82064d6d>] __lock_acquire+0x79a/0x7f1
[<ffffffff82065a81>] lock_acquire+0xc6/0xed
[<ffffffffa0604ff8>] start_this_handle+0x4a3/0x4bc [jbd2]
[<ffffffffa06051d6>] jbd2__journal_start+0xba/0xee [jbd2]
[<ffffffffa0605218>] jbd2_journal_start+0xe/0x10 [jbd2]
[<ffffffffa065ca34>] ocfs2_start_trans+0xb7/0x19b [ocfs2]
[<ffffffffa06645f3>] ocfs2_mknod+0x73e/0xfea [ocfs2]
[<ffffffffa0665041>] ocfs2_create+0x9d/0x105 [ocfs2]
[<ffffffff820e1c83>] vfs_create+0x9b/0xf4
[<ffffffff820e20bb>] do_last+0x2fd/0x5be
[<ffffffff820e31c0>] do_filp_open+0x1fb/0x572
[<ffffffff820d6cf6>] do_sys_open+0x5a/0xe7
[<ffffffff820d6dac>] sys_open+0x1b/0x1d
[<ffffffff8200296b>] system_call_fastpath+0x16/0x1b
-> #1 (&journal->j_trans_barrier){.+.+..}:
[<ffffffff82064d6d>] __lock_acquire+0x79a/0x7f1
[<ffffffff82064fa9>] lock_release_non_nested+0x1e5/0x24b
[<ffffffff82065999>] lock_release+0x158/0x17a
[<ffffffff823389f6>] __mutex_unlock_slowpath+0xbf/0x11b
[<ffffffff82338a5b>] mutex_unlock+0x9/0xb
[<ffffffffa0679673>] ocfs2_free_ac_resource+0x31/0x67 [ocfs2]
[<ffffffffa067c6bc>] ocfs2_free_alloc_context+0x11/0x1d [ocfs2]
[<ffffffffa0633de0>] ocfs2_write_begin_nolock+0x141e/0x159b [ocfs2]
[<ffffffffa0635523>] ocfs2_write_begin+0x11e/0x1e7 [ocfs2]
[<ffffffff820a1297>] generic_file_buffered_write+0x10c/0x210
[<ffffffffa0653624>] ocfs2_file_aio_write+0x4cc/0x6d3 [ocfs2]
[<ffffffff820d822d>] do_sync_write+0xc2/0x106
[<ffffffff820d897b>] vfs_write+0xae/0x131
[<ffffffff820d8e55>] sys_write+0x47/0x6f
[<ffffffff8200296b>] system_call_fastpath+0x16/0x1b
-> #0 (&oi->ip_alloc_sem){+.+.+.}:
[<ffffffff82063f92>] validate_chain+0x727/0xd68
[<ffffffff82064d6d>] __lock_acquire+0x79a/0x7f1
[<ffffffff82065a81>] lock_acquire+0xc6/0xed
[<ffffffff82339694>] down_write+0x31/0x52
[<ffffffffa0673b67>] ocfs2_reflink_ioctl+0x69a/0x1226 [ocfs2]
[<ffffffffa06599f6>] ocfs2_ioctl+0x61a/0x656 [ocfs2]
[<ffffffff820e53ac>] vfs_ioctl+0x2a/0x9d
[<ffffffff820e5903>] do_vfs_ioctl+0x45d/0x4ae
[<ffffffff820e59ab>] sys_ioctl+0x57/0x7a
[<ffffffff8200296b>] system_call_fastpath+0x16/0x1b
Signed-off-by: Tao Ma <tao.ma@oracle.com>
---
fs/ocfs2/xattr.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index d03469f..06fa5e7 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -1286,13 +1286,11 @@ int ocfs2_xattr_get_nolock(struct inode *inode,
xis.inode_bh = xbs.inode_bh = di_bh;
di = (struct ocfs2_dinode *)di_bh->b_data;
- down_read(&oi->ip_xattr_sem);
ret = ocfs2_xattr_ibody_get(inode, name_index, name, buffer,
buffer_size, &xis);
if (ret == -ENODATA && di->i_xattr_loc)
ret = ocfs2_xattr_block_get(inode, name_index, name, buffer,
buffer_size, &xbs);
- up_read(&oi->ip_xattr_sem);
return ret;
}
@@ -1316,8 +1314,10 @@ static int ocfs2_xattr_get(struct inode *inode,
mlog_errno(ret);
return ret;
}
+ down_read(&OCFS2_I(inode)->ip_xattr_sem);
ret = ocfs2_xattr_get_nolock(inode, di_bh, name_index,
name, buffer, buffer_size);
+ up_read(&OCFS2_I(inode)->ip_xattr_sem);
ocfs2_inode_unlock(inode, 0);
--
1.7.1.GIT
^ permalink raw reply related [flat|nested] 5+ messages in thread* [Ocfs2-devel] [PATCH 2/2] ocfs2: Fix lockdep warning in reflink.
2010-09-07 5:29 [Ocfs2-devel] [PATCH 0/2] Fix 2 lockdep warning in ocfs2 Tao Ma
2010-09-07 5:30 ` [Ocfs2-devel] [PATCH 1/2] ocfs2/lockdep: Move ip_xattr_sem out of ocfs2_xattr_get_nolock Tao Ma
@ 2010-09-07 5:30 ` Tao Ma
2010-09-10 16:21 ` Joel Becker
1 sibling, 1 reply; 5+ messages in thread
From: Tao Ma @ 2010-09-07 5:30 UTC (permalink / raw)
To: ocfs2-devel
This patch change mutex_lock to a new subclass and
add a new inode lock subclass for the target inode
which caused this lockdep warning.
=============================================
[ INFO: possible recursive locking detected ]
2.6.35+ #5
---------------------------------------------
reflink/11086 is trying to acquire lock:
(Meta){+++++.}, at: [<ffffffffa06f9d65>] ocfs2_reflink_ioctl+0x898/0x1229 [ocfs2]
but task is already holding lock:
(Meta){+++++.}, at: [<ffffffffa06f9aa0>] ocfs2_reflink_ioctl+0x5d3/0x1229 [ocfs2]
other info that might help us debug this:
6 locks held by reflink/11086:
#0: (&sb->s_type->i_mutex_key#15/1){+.+.+.}, at: [<ffffffff820e09ec>] lookup_create+0x26/0x97
#1: (&sb->s_type->i_mutex_key#15){+.+.+.}, at: [<ffffffffa06f99a0>] ocfs2_reflink_ioctl+0x4d3/0x1229 [ocfs2]
#2: (Meta){+++++.}, at: [<ffffffffa06f9aa0>] ocfs2_reflink_ioctl+0x5d3/0x1229 [ocfs2]
#3: (&oi->ip_xattr_sem){+.+.+.}, at: [<ffffffffa06f9b58>] ocfs2_reflink_ioctl+0x68b/0x1229 [ocfs2]
#4: (&oi->ip_alloc_sem){+.+.+.}, at: [<ffffffffa06f9b67>] ocfs2_reflink_ioctl+0x69a/0x1229 [ocfs2]
#5: (&sb->s_type->i_mutex_key#15/2){+.+...}, at: [<ffffffffa06f9d4f>] ocfs2_reflink_ioctl+0x882/0x1229 [ocfs2]
stack backtrace:
Pid: 11086, comm: reflink Not tainted 2.6.35+ #5
Call Trace:
[<ffffffff82063dd9>] validate_chain+0x56e/0xd68
[<ffffffff82062275>] ? mark_held_locks+0x49/0x69
[<ffffffff82064d6d>] __lock_acquire+0x79a/0x7f1
[<ffffffff82065a81>] lock_acquire+0xc6/0xed
[<ffffffffa06f9d65>] ? ocfs2_reflink_ioctl+0x898/0x1229 [ocfs2]
[<ffffffffa06c9ade>] __ocfs2_cluster_lock+0x975/0xa0d [ocfs2]
[<ffffffffa06f9d65>] ? ocfs2_reflink_ioctl+0x898/0x1229 [ocfs2]
[<ffffffffa06e107b>] ? ocfs2_wait_for_recovery+0x15/0x8a [ocfs2]
[<ffffffffa06cb6ea>] ocfs2_inode_lock_full_nested+0x1ac/0xdc5 [ocfs2]
[<ffffffffa06f9d65>] ? ocfs2_reflink_ioctl+0x898/0x1229 [ocfs2]
[<ffffffff820623a0>] ? trace_hardirqs_on_caller+0x10b/0x12f
[<ffffffff82060193>] ? debug_mutex_free_waiter+0x4f/0x53
[<ffffffffa06f9d65>] ocfs2_reflink_ioctl+0x898/0x1229 [ocfs2]
[<ffffffffa06ce24a>] ? ocfs2_file_lock_res_init+0x66/0x78 [ocfs2]
[<ffffffff820bb2d2>] ? might_fault+0x40/0x8d
[<ffffffffa06df9f6>] ocfs2_ioctl+0x61a/0x656 [ocfs2]
[<ffffffff820ee5d3>] ? mntput_no_expire+0x1d/0xb0
[<ffffffff820e07b3>] ? path_put+0x2c/0x31
[<ffffffff820e53ac>] vfs_ioctl+0x2a/0x9d
[<ffffffff820e5903>] do_vfs_ioctl+0x45d/0x4ae
[<ffffffff8233a7f6>] ? _raw_spin_unlock+0x26/0x2a
[<ffffffff8200299c>] ? sysret_check+0x27/0x62
[<ffffffff820e59ab>] sys_ioctl+0x57/0x7a
[<ffffffff8200296b>] system_call_fastpath+0x16/0x1b
Signed-off-by: Tao Ma <tao.ma@oracle.com>
---
fs/ocfs2/dlmglue.h | 1 +
fs/ocfs2/refcounttree.c | 5 +++--
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/ocfs2/dlmglue.h b/fs/ocfs2/dlmglue.h
index d1ce48e..1d596d8 100644
--- a/fs/ocfs2/dlmglue.h
+++ b/fs/ocfs2/dlmglue.h
@@ -84,6 +84,7 @@ enum {
OI_LS_PARENT,
OI_LS_RENAME1,
OI_LS_RENAME2,
+ OI_LS_REFLINK_TARGET,
};
int ocfs2_dlm_init(struct ocfs2_super *osb);
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 73a11cc..588cacd 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -4200,8 +4200,9 @@ static int __ocfs2_reflink(struct dentry *old_dentry,
goto out;
}
- mutex_lock(&new_inode->i_mutex);
- ret = ocfs2_inode_lock(new_inode, &new_bh, 1);
+ mutex_lock_nested(&new_inode->i_mutex, I_MUTEX_CHILD);
+ ret = ocfs2_inode_lock_nested(new_inode, &new_bh, 1,
+ OI_LS_REFLINK_TARGET);
if (ret) {
mlog_errno(ret);
goto out_unlock;
--
1.7.1.GIT
^ permalink raw reply related [flat|nested] 5+ messages in thread