Use KM_NOFS for debug trace buffers

Use KM_NOFS to prevent recursion back into the filesystem which can cause deadlocks.

In the case of xfs_iread() we hold the lock on the inode cluster buffer while allocating memory for the trace buffers. If we recurse back into XFS to flush data that may require a transaction to allocate extents which needs log space. This can deadlock with the xfsaild thread which can't push the tail of the log because it is trying to get the inode cluster buffer lock.

@@ -1795,7 +1795,7 @@ int __init

xfs_buf_init(void)
{
#ifdef XFS_BUF_TRACE
- xfs_buf_trace_buf = ktrace_alloc(XFS_BUF_TRACE_SIZE, KM_SLEEP);
+ xfs_buf_trace_buf = ktrace_alloc(XFS_BUF_TRACE_SIZE, KM_NOFS);
#endif

xfs_buf_zone = kmem_zone_init_flags(sizeof(xfs_buf_t), "xfs_buf",

@@ -105,7 +105,7 @@ xfs_qm_dqinit(

		sv_init(&dqp->q_pinwait, SV_DEFAULT, "pdq");

#ifdef XFS_DQUOT_TRACE
- dqp->q_trace = ktrace_alloc(DQUOT_TRACE_SIZE, KM_SLEEP);

+		dqp->q_trace = ktrace_alloc(DQUOT_TRACE_SIZE, KM_NOFS);
		xfs_dqtrace_entry(dqp, "DQINIT");
#endif
	} else {

@@ -737,7 +737,7 @@ xfs_buf_item_init(

	bip->bli_format.blf_len = (ushort)BTOBB(XFS_BUF_COUNT(bp));
	bip->bli_format.blf_map_size = map_size;

#ifdef XFS_BLI_TRACE
- bip->bli_trace = ktrace_alloc(XFS_BLI_TRACE_SIZE, KM_SLEEP);
+ bip->bli_trace = ktrace_alloc(XFS_BLI_TRACE_SIZE, KM_NOFS);
#endif

#ifdef XFS_TRANS_DEBUG

@@ -400,7 +400,7 @@ xfs_filestream_init(void)

	if (!item_zone)
		return -ENOMEM;
#ifdef XFS_FILESTREAMS_TRACE
-	xfs_filestreams_trace_buf = ktrace_alloc(XFS_FSTRM_KTRACE_SIZE, KM_SLEEP);
+	xfs_filestreams_trace_buf = ktrace_alloc(XFS_FSTRM_KTRACE_SIZE, KM_NOFS);
#endif
	return 0;
}

@@ -835,22 +835,22 @@ xfs_iread(

	 * Do this before xfs_iformat in case it adds entries.
	 */

#ifdef XFS_INODE_TRACE
- ip->i_trace = ktrace_alloc(INODE_TRACE_SIZE, KM_SLEEP);
+ ip->i_trace = ktrace_alloc(INODE_TRACE_SIZE, KM_NOFS);
#endif
#ifdef XFS_BMAP_TRACE
- ip->i_xtrace = ktrace_alloc(XFS_BMAP_KTRACE_SIZE, KM_SLEEP);
+ ip->i_xtrace = ktrace_alloc(XFS_BMAP_KTRACE_SIZE, KM_NOFS);
#endif
#ifdef XFS_BMBT_TRACE
- ip->i_btrace = ktrace_alloc(XFS_BMBT_KTRACE_SIZE, KM_SLEEP);
+ ip->i_btrace = ktrace_alloc(XFS_BMBT_KTRACE_SIZE, KM_NOFS);
#endif
#ifdef XFS_RW_TRACE
- ip->i_rwtrace = ktrace_alloc(XFS_RW_KTRACE_SIZE, KM_SLEEP);
+ ip->i_rwtrace = ktrace_alloc(XFS_RW_KTRACE_SIZE, KM_NOFS);
#endif
#ifdef XFS_ILOCK_TRACE
- ip->i_lock_trace = ktrace_alloc(XFS_ILOCK_KTRACE_SIZE, KM_SLEEP);
+ ip->i_lock_trace = ktrace_alloc(XFS_ILOCK_KTRACE_SIZE, KM_NOFS);
#endif
#ifdef XFS_DIR2_TRACE
- ip->i_dir_trace = ktrace_alloc(XFS_DIR2_KTRACE_SIZE, KM_SLEEP);
+ ip->i_dir_trace = ktrace_alloc(XFS_DIR2_KTRACE_SIZE, KM_NOFS);
#endif

	/*

@@ -160,7 +160,7 @@ void

xlog_trace_iclog(xlog_in_core_t *iclog, uint state)

{
	if (!iclog->ic_trace)
-		iclog->ic_trace = ktrace_alloc(256, KM_SLEEP);
+		iclog->ic_trace = ktrace_alloc(256, KM_NOFS);
	ktrace_enter(iclog->ic_trace,
		     (void *)((unsigned long)state),
		     (void *)((unsigned long)current_pid()),

Looks OK.

Cheers,

Dave.

Dave Chinner
[email protected]