[PATCH 14/29] xfs: support nowait for xfs_log_reserve()

[Hao Xu]

From: Hao Xu <howeyxu@xxxxxxxxxxx>

Support nowait logic for xfs_log_reserve(), including add a nowait
boolean parameter and error out -EAGAIN for ticket allocation.

Signed-off-by: Hao Xu <howeyxu@xxxxxxxxxxx>
---
 fs/xfs/xfs_log.c      | 18 +++++++++++++-----
 fs/xfs/xfs_log.h      |  5 +++--
 fs/xfs/xfs_log_cil.c  |  2 +-
 fs/xfs/xfs_log_priv.h |  2 +-
 fs/xfs/xfs_trans.c    |  5 +++--
 5 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 79004d193e54..90fbb1c0eca2 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -462,7 +462,8 @@ xfs_log_reserve(
 	int			unit_bytes,
 	int			cnt,
 	struct xlog_ticket	**ticp,
-	bool			permanent)
+	bool			permanent,
+	bool			nowait)
 {
 	struct xlog		*log = mp->m_log;
 	struct xlog_ticket	*tic;
@@ -475,7 +476,9 @@ xfs_log_reserve(
 	XFS_STATS_INC(mp, xs_try_logspace);
 
 	ASSERT(*ticp == NULL);
-	tic = xlog_ticket_alloc(log, unit_bytes, cnt, permanent);
+	tic = xlog_ticket_alloc(log, unit_bytes, cnt, permanent, nowait);
+	if (!tic)
+		return -EAGAIN;
 	*ticp = tic;
 
 	xlog_grant_push_ail(log, tic->t_cnt ? tic->t_unit_res * tic->t_cnt
@@ -974,7 +977,7 @@ xlog_unmount_write(
 	struct xlog_ticket	*tic = NULL;
 	int			error;
 
-	error = xfs_log_reserve(mp, 600, 1, &tic, 0);
+	error = xfs_log_reserve(mp, 600, 1, &tic, 0, false);
 	if (error)
 		goto out_err;
 
@@ -3527,12 +3530,17 @@ xlog_ticket_alloc(
 	struct xlog		*log,
 	int			unit_bytes,
 	int			cnt,
-	bool			permanent)
+	bool			permanent,
+	bool			nowait)
 {
 	struct xlog_ticket	*tic;
 	int			unit_res;
 
-	tic = kmem_cache_zalloc(xfs_log_ticket_cache, GFP_NOFS | __GFP_NOFAIL);
+	gfp_t			gfp_flags = GFP_NOFS |
+					    (nowait ? 0 : __GFP_NOFAIL);
+	tic = kmem_cache_zalloc(xfs_log_ticket_cache, gfp_flags);
+	if (!tic)
+		return NULL;
 
 	unit_res = xlog_calc_unit_res(log, unit_bytes, &tic->t_iclog_hdrs);
 
diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h
index 2728886c2963..ba515df443c3 100644
--- a/fs/xfs/xfs_log.h
+++ b/fs/xfs/xfs_log.h
@@ -139,8 +139,9 @@ void	xfs_log_mount_cancel(struct xfs_mount *);
 xfs_lsn_t xlog_assign_tail_lsn(struct xfs_mount *mp);
 xfs_lsn_t xlog_assign_tail_lsn_locked(struct xfs_mount *mp);
 void	xfs_log_space_wake(struct xfs_mount *mp);
-int	xfs_log_reserve(struct xfs_mount *mp, int length, int count,
-			struct xlog_ticket **ticket, bool permanent);
+int	xfs_log_reserve(struct xfs_mount *mp, int length,
+			int count, struct xlog_ticket **ticket,
+			bool permanent, bool nowait);
 int	xfs_log_regrant(struct xfs_mount *mp, struct xlog_ticket *tic);
 void	xfs_log_unmount(struct xfs_mount *mp);
 bool	xfs_log_writable(struct xfs_mount *mp);
diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c
index eccbfb99e894..f17c1799b3c4 100644
--- a/fs/xfs/xfs_log_cil.c
+++ b/fs/xfs/xfs_log_cil.c
@@ -37,7 +37,7 @@ xlog_cil_ticket_alloc(
 {
 	struct xlog_ticket *tic;
 
-	tic = xlog_ticket_alloc(log, 0, 1, 0);
+	tic = xlog_ticket_alloc(log, 0, 1, 0, false);
 
 	/*
 	 * set the current reservation to zero so we know to steal the basic
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index 1bd2963e8fbd..41edaa0ae869 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -503,7 +503,7 @@ extern __le32	 xlog_cksum(struct xlog *log, struct xlog_rec_header *rhead,
 
 extern struct kmem_cache *xfs_log_ticket_cache;
 struct xlog_ticket *xlog_ticket_alloc(struct xlog *log, int unit_bytes,
-		int count, bool permanent);
+		int count, bool permanent, bool nowait);
 
 void	xlog_print_tic_res(struct xfs_mount *mp, struct xlog_ticket *ticket);
 void	xlog_print_trans(struct xfs_trans *);
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index dbec685f4f4a..7988b4c7f36e 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -155,6 +155,7 @@ xfs_trans_reserve(
 	struct xfs_mount	*mp = tp->t_mountp;
 	int			error = 0;
 	bool			rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0;
+	bool			nowait = tp->t_flags & XFS_TRANS_NOWAIT;
 
 	/*
 	 * Attempt to reserve the needed disk blocks by decrementing
@@ -192,8 +193,8 @@ xfs_trans_reserve(
 			error = xfs_log_regrant(mp, tp->t_ticket);
 		} else {
 			error = xfs_log_reserve(mp, resp->tr_logres,
-						resp->tr_logcount,
-						&tp->t_ticket, permanent);
+						resp->tr_logcount, &tp->t_ticket,
+						permanent, nowait);
 		}
 
 		if (error)
-- 
2.25.1