Commit c704ecb2 authored by Dave Chinner's avatar Dave Chinner Committed by Chandan Babu R
Browse files

xfs: place the CIL under nofs allocation context 



This is core code that needs to run in low memory conditions and
can be triggered from memory reclaim. While it runs in a workqueue,
it really shouldn't be recursing back into the filesystem during
any memory allocation it needs to function.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatar"Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
parent 2c1e31ed

fs/xfs/xfs_log_cil.c

+12 −1
Original line number Diff line number Diff line
@@ -100,7 +100,7 @@ xlog_cil_ctx_alloc(void) 
{

	struct xfs_cil_ctx	*ctx;



	ctx = kzalloc(sizeof(*ctx), GFP_NOFS | __GFP_NOFAIL);

	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL | __GFP_NOFAIL);

	INIT_LIST_HEAD(&ctx->committing);

	INIT_LIST_HEAD(&ctx->busy_extents.extent_list);

	INIT_LIST_HEAD(&ctx->log_items);
@@ -1116,11 +1116,18 @@ xlog_cil_cleanup_whiteouts( 
 * same sequence twice.  If we get a race between multiple pushes for the same

 * sequence they will block on the first one and then abort, hence avoiding

 * needless pushes.

 *

 * This runs from a workqueue so it does not inherent any specific memory

 * allocation context. However, we do not want to block on memory reclaim

 * recursing back into the filesystem because this push may have been triggered

 * by memory reclaim itself. Hence we really need to run under full GFP_NOFS

 * contraints here.

 */

static void

xlog_cil_push_work(

	struct work_struct	*work)

{

	unsigned int		nofs_flags = memalloc_nofs_save();

	struct xfs_cil_ctx	*ctx =

		container_of(work, struct xfs_cil_ctx, push_work);

	struct xfs_cil		*cil = ctx->cil;
@@ -1334,12 +1341,14 @@ xlog_cil_push_work( 
	spin_unlock(&log->l_icloglock);

	xlog_cil_cleanup_whiteouts(&whiteouts);

	xfs_log_ticket_ungrant(log, ticket);

	memalloc_nofs_restore(nofs_flags);

	return;



out_skip:

	up_write(&cil->xc_ctx_lock);

	xfs_log_ticket_put(new_ctx->ticket);

	kfree(new_ctx);

	memalloc_nofs_restore(nofs_flags);

	return;



out_abort_free_ticket:
@@ -1348,6 +1357,7 @@ xlog_cil_push_work( 
	if (!ctx->commit_iclog) {

		xfs_log_ticket_ungrant(log, ctx->ticket);

		xlog_cil_committed(ctx);

		memalloc_nofs_restore(nofs_flags);

		return;

	}

	spin_lock(&log->l_icloglock);
@@ -1356,6 +1366,7 @@ xlog_cil_push_work( 
	/* Not safe to reference ctx now! */

	spin_unlock(&log->l_icloglock);

	xfs_log_ticket_ungrant(log, ticket);

	memalloc_nofs_restore(nofs_flags);

}



/*