X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=blobdiff_plain;f=lustre%2Fosc%2Fosc_cache.c;h=4d97b3e028be984345aa987486338db13b63f49f;hp=581beb6013314f01a28948bab94c70dec4d638e7;hb=27815a0611a2e315a9a7696a20c2f257d48aeb7e;hpb=66be2e6014a7bf20b2f749c877cb141b209f15d9

diff --git a/lustre/osc/osc_cache.c b/lustre/osc/osc_cache.c
index 581beb6..4d97b3e 100644
--- a/lustre/osc/osc_cache.c
+++ b/lustre/osc/osc_cache.c
@@ -27,7 +27,7 @@
  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2012, Intel Corporation.
+ * Copyright (c) 2012, 2013, Intel Corporation.
  *
  */
 /*
@@ -99,27 +99,28 @@ static inline char list_empty_marker(cfs_list_t *list)
 
 #define EXTSTR       "[%lu -> %lu/%lu]"
 #define EXTPARA(ext) (ext)->oe_start, (ext)->oe_end, (ext)->oe_max_end
+static const char *oes_strings[] = {
+	"inv", "active", "cache", "locking", "lockdone", "rpc", "trunc", NULL };
 
 #define OSC_EXTENT_DUMP(lvl, extent, fmt, ...) do {			      \
 	struct osc_extent *__ext = (extent);				      \
-	const char *__str[] = OES_STRINGS;				      \
 	char __buf[16];							      \
 									      \
 	CDEBUG(lvl,							      \
 		"extent %p@{" EXTSTR ", "				      \
 		"[%d|%d|%c|%s|%s|%p], [%d|%d|%c|%c|%p|%u|%p]} " fmt,	      \
-		/* ----- extent part 0 ----- */			              \
+		/* ----- extent part 0 ----- */				      \
 		__ext, EXTPARA(__ext),					      \
 		/* ----- part 1 ----- */				      \
 		cfs_atomic_read(&__ext->oe_refc),			      \
 		cfs_atomic_read(&__ext->oe_users),			      \
 		list_empty_marker(&__ext->oe_link),			      \
-		__str[__ext->oe_state], ext_flags(__ext, __buf),	      \
+		oes_strings[__ext->oe_state], ext_flags(__ext, __buf),	      \
 		__ext->oe_obj,						      \
 		/* ----- part 2 ----- */				      \
 		__ext->oe_grants, __ext->oe_nr_pages,			      \
 		list_empty_marker(&__ext->oe_pages),			      \
-		cfs_waitq_active(&__ext->oe_waitq) ? '+' : '-',		      \
+		waitqueue_active(&__ext->oe_waitq) ? '+' : '-',		      \
 		__ext->oe_osclock, __ext->oe_mppr, __ext->oe_owner,	      \
 		/* ----- part 4 ----- */				      \
 		## __VA_ARGS__);					      \
@@ -128,10 +129,10 @@ static inline char list_empty_marker(cfs_list_t *list)
 #undef EASSERTF
 #define EASSERTF(expr, ext, fmt, args...) do {				\
 	if (!(expr)) {							\
-		OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);		 \
-		osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);		 \
+		OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);		\
+		osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);		\
 		LASSERT(expr);						\
-	}								     \
+	}								\
 } while (0)
 
 #undef EASSERT
@@ -301,14 +302,14 @@ static void osc_extent_state_set(struct osc_extent *ext, int state)
 
 	/* TODO: validate the state machine */
 	ext->oe_state = state;
-	cfs_waitq_broadcast(&ext->oe_waitq);
+	wake_up_all(&ext->oe_waitq);
 }
 
 static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
 {
 	struct osc_extent *ext;
 
-	OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, CFS_ALLOC_STD);
+	OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, GFP_IOFS);
 	if (ext == NULL)
 		return NULL;
 
@@ -319,7 +320,7 @@ static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
 	CFS_INIT_LIST_HEAD(&ext->oe_link);
 	ext->oe_state = OES_INV;
 	CFS_INIT_LIST_HEAD(&ext->oe_pages);
-	cfs_waitq_init(&ext->oe_waitq);
+	init_waitqueue_head(&ext->oe_waitq);
 	ext->oe_osclock = NULL;
 
 	return ext;
@@ -504,7 +505,7 @@ static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
 		return -ERANGE;
 
 	LASSERT(cur->oe_osclock == victim->oe_osclock);
-	ppc_bits = osc_cli(obj)->cl_chunkbits - CFS_PAGE_SHIFT;
+	ppc_bits = osc_cli(obj)->cl_chunkbits - PAGE_CACHE_SHIFT;
 	chunk_start = cur->oe_start >> ppc_bits;
 	chunk_end   = cur->oe_end   >> ppc_bits;
 	if (chunk_start   != (victim->oe_end >> ppc_bits) + 1 &&
@@ -611,8 +612,8 @@ struct osc_extent *osc_extent_find(const struct lu_env *env,
 	LASSERT(lock != NULL);
 	LASSERT(lock->cll_descr.cld_mode >= CLM_WRITE);
 
-	LASSERT(cli->cl_chunkbits >= CFS_PAGE_SHIFT);
-	ppc_bits   = cli->cl_chunkbits - CFS_PAGE_SHIFT;
+	LASSERT(cli->cl_chunkbits >= PAGE_CACHE_SHIFT);
+	ppc_bits   = cli->cl_chunkbits - PAGE_CACHE_SHIFT;
 	chunk_mask = ~((1 << ppc_bits) - 1);
 	chunksize  = 1 << cli->cl_chunkbits;
 	chunk      = index >> ppc_bits;
@@ -826,8 +827,8 @@ int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
 
 	if (!sent) {
 		lost_grant = ext->oe_grants;
-	} else if (blocksize < CFS_PAGE_SIZE &&
-		   last_count != CFS_PAGE_SIZE) {
+	} else if (blocksize < PAGE_CACHE_SIZE &&
+		   last_count != PAGE_CACHE_SIZE) {
 		/* For short writes we shouldn't count parts of pages that
 		 * span a whole chunk on the OST side, or our accounting goes
 		 * wrong.  Should match the code in filter_grant_check. */
@@ -837,7 +838,7 @@ int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
 		if (end)
 			count += blocksize - end;
 
-		lost_grant = CFS_PAGE_SIZE - count;
+		lost_grant = PAGE_CACHE_SIZE - count;
 	}
 	if (ext->oe_grants > 0)
 		osc_free_grant(cli, nr_pages, lost_grant);
@@ -895,7 +896,7 @@ static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
 			"%s: wait ext to %d timedout, recovery in progress?\n",
 			osc_export(obj)->exp_obd->obd_name, state);
 
-		lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
+		lwi = LWI_INTR(NULL, NULL);
 		rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state),
 				  &lwi);
 	}
@@ -919,7 +920,8 @@ static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
 	struct osc_async_page *oap;
 	struct osc_async_page *tmp;
 	int                    pages_in_chunk = 0;
-	int                    ppc_bits    = cli->cl_chunkbits - CFS_PAGE_SHIFT;
+	int                    ppc_bits    = cli->cl_chunkbits -
+					     PAGE_CACHE_SHIFT;
 	__u64                  trunc_chunk = trunc_index >> ppc_bits;
 	int                    grants   = 0;
 	int                    nr_pages = 0;
@@ -962,7 +964,7 @@ static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
 		cfs_list_del_init(&oap->oap_pending_item);
 
 		cl_page_get(page);
-		lu_ref_add(&page->cp_reference, "truncate", cfs_current());
+		lu_ref_add(&page->cp_reference, "truncate", current);
 
 		if (cl_page_own(env, io, page) == 0) {
 			cl_page_unmap(env, io, page);
@@ -973,7 +975,7 @@ static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
 			LASSERT(0);
 		}
 
-		lu_ref_del(&page->cp_reference, "truncate", cfs_current());
+		lu_ref_del(&page->cp_reference, "truncate", current);
 		cl_page_put(env, page);
 
 		--ext->oe_nr_pages;
@@ -1076,16 +1078,20 @@ static int osc_extent_make_ready(const struct lu_env *env,
 	if (!(last->oap_async_flags & ASYNC_COUNT_STABLE)) {
 		last->oap_count = osc_refresh_count(env, last, OBD_BRW_WRITE);
 		LASSERT(last->oap_count > 0);
-		LASSERT(last->oap_page_off + last->oap_count <= CFS_PAGE_SIZE);
+		LASSERT(last->oap_page_off + last->oap_count <= PAGE_CACHE_SIZE);
+		spin_lock(&last->oap_lock);
 		last->oap_async_flags |= ASYNC_COUNT_STABLE;
+		spin_unlock(&last->oap_lock);
 	}
 
 	/* for the rest of pages, we don't need to call osf_refresh_count()
 	 * because it's known they are not the last page */
 	cfs_list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
 		if (!(oap->oap_async_flags & ASYNC_COUNT_STABLE)) {
-			oap->oap_count = CFS_PAGE_SIZE - oap->oap_page_off;
+			oap->oap_count = PAGE_CACHE_SIZE - oap->oap_page_off;
+			spin_lock(&oap->oap_lock);
 			oap->oap_async_flags |= ASYNC_COUNT_STABLE;
+			spin_unlock(&oap->oap_lock);
 		}
 	}
 
@@ -1108,7 +1114,7 @@ static int osc_extent_expand(struct osc_extent *ext, pgoff_t index, int *grants)
 	struct osc_object *obj = ext->oe_obj;
 	struct client_obd *cli = osc_cli(obj);
 	struct osc_extent *next;
-	int ppc_bits = cli->cl_chunkbits - CFS_PAGE_SHIFT;
+	int ppc_bits = cli->cl_chunkbits - PAGE_CACHE_SHIFT;
 	pgoff_t chunk = index >> ppc_bits;
 	pgoff_t end_chunk;
 	pgoff_t end_index;
@@ -1240,9 +1246,9 @@ static int osc_refresh_count(const struct lu_env *env,
 		return 0;
 	else if (cl_offset(obj, page->cp_index + 1) > kms)
 		/* catch sub-page write at end of file */
-		return kms % CFS_PAGE_SIZE;
+		return kms % PAGE_CACHE_SIZE;
 	else
-		return CFS_PAGE_SIZE;
+		return PAGE_CACHE_SIZE;
 }
 
 static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
@@ -1257,8 +1263,10 @@ static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
 	ENTRY;
 
 	cmd &= ~OBD_BRW_NOQUOTA;
-	LASSERT(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ));
-	LASSERT(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE));
+	LASSERTF(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ),
+		 "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
+	LASSERTF(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE),
+		"cp_state:%u, cmd:%d\n", page->cp_state, cmd);
 	LASSERT(opg->ops_transfer_pinned);
 
 	/*
@@ -1307,28 +1315,34 @@ static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
 	RETURN(0);
 }
 
-#define OSC_DUMP_GRANT(cli, fmt, args...) do {				      \
+#define OSC_DUMP_GRANT(lvl, cli, fmt, args...) do {			      \
 	struct client_obd *__tmp = (cli);				      \
-	CDEBUG(D_CACHE, "%s: { dirty: %ld/%ld dirty_pages: %d/%d "	      \
-	       "dropped: %ld avail: %ld, reserved: %ld, flight: %d } " fmt,   \
+	CDEBUG(lvl, "%s: grant { dirty: %ld/%ld dirty_pages: %d/%d "	      \
+	       "unstable_pages: %d/%d dropped: %ld avail: %ld, "	      \
+	       "reserved: %ld, flight: %d } lru {in list: %d, "		      \
+	       "left: %d, waiters: %d }" fmt,				      \
 	       __tmp->cl_import->imp_obd->obd_name,			      \
 	       __tmp->cl_dirty, __tmp->cl_dirty_max,			      \
 	       cfs_atomic_read(&obd_dirty_pages), obd_max_dirty_pages,	      \
+	       cfs_atomic_read(&obd_unstable_pages), obd_max_dirty_pages,     \
 	       __tmp->cl_lost_grant, __tmp->cl_avail_grant,		      \
-	       __tmp->cl_reserved_grant, __tmp->cl_w_in_flight, ##args);      \
+	       __tmp->cl_reserved_grant, __tmp->cl_w_in_flight,		      \
+	       cfs_atomic_read(&__tmp->cl_lru_in_list),			      \
+	       cfs_atomic_read(&__tmp->cl_lru_busy),			      \
+	       cfs_atomic_read(&__tmp->cl_lru_shrinkers), ##args);	      \
 } while (0)
 
 /* caller must hold loi_list_lock */
 static void osc_consume_write_grant(struct client_obd *cli,
 				    struct brw_page *pga)
 {
-	LASSERT_SPIN_LOCKED(&cli->cl_loi_list_lock.lock);
+	LASSERT(spin_is_locked(&cli->cl_loi_list_lock.lock));
 	LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT));
 	cfs_atomic_inc(&obd_dirty_pages);
-	cli->cl_dirty += CFS_PAGE_SIZE;
+	cli->cl_dirty += PAGE_CACHE_SIZE;
 	pga->flag |= OBD_BRW_FROM_GRANT;
 	CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n",
-	       CFS_PAGE_SIZE, pga, pga->pg);
+	       PAGE_CACHE_SIZE, pga, pga->pg);
 	osc_update_next_shrink(cli);
 }
 
@@ -1339,7 +1353,7 @@ static void osc_release_write_grant(struct client_obd *cli,
 {
 	ENTRY;
 
-	LASSERT_SPIN_LOCKED(&cli->cl_loi_list_lock.lock);
+	LASSERT(spin_is_locked(&cli->cl_loi_list_lock.lock));
 	if (!(pga->flag & OBD_BRW_FROM_GRANT)) {
 		EXIT;
 		return;
@@ -1347,11 +1361,11 @@ static void osc_release_write_grant(struct client_obd *cli,
 
 	pga->flag &= ~OBD_BRW_FROM_GRANT;
 	cfs_atomic_dec(&obd_dirty_pages);
-	cli->cl_dirty -= CFS_PAGE_SIZE;
+	cli->cl_dirty -= PAGE_CACHE_SIZE;
 	if (pga->flag & OBD_BRW_NOCACHE) {
 		pga->flag &= ~OBD_BRW_NOCACHE;
 		cfs_atomic_dec(&obd_dirty_transit_pages);
-		cli->cl_dirty_transit -= CFS_PAGE_SIZE;
+		cli->cl_dirty_transit -= PAGE_CACHE_SIZE;
 	}
 	EXIT;
 }
@@ -1407,7 +1421,7 @@ void osc_unreserve_grant(struct client_obd *cli,
  * used, we should return these grants to OST. There're two cases where grants
  * can be lost:
  * 1. truncate;
- * 2. blocksize at OST is less than CFS_PAGE_SIZE and a partial page was
+ * 2. blocksize at OST is less than PAGE_CACHE_SIZE and a partial page was
  *    written. In this case OST may use less chunks to serve this partial
  *    write. OSTs don't actually know the page size on the client side. so
  *    clients have to calculate lost grant by the blocksize on the OST.
@@ -1420,7 +1434,7 @@ static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
 
 	client_obd_list_lock(&cli->cl_loi_list_lock);
 	cfs_atomic_sub(nr_pages, &obd_dirty_pages);
-	cli->cl_dirty -= nr_pages << CFS_PAGE_SHIFT;
+	cli->cl_dirty -= nr_pages << PAGE_CACHE_SHIFT;
 	cli->cl_lost_grant += lost_grant;
 	if (cli->cl_avail_grant < grant && cli->cl_lost_grant >= grant) {
 		/* borrow some grant from truncate to avoid the case that
@@ -1456,17 +1470,18 @@ static int osc_enter_cache_try(struct client_obd *cli,
 {
 	int rc;
 
-	OSC_DUMP_GRANT(cli, "need:%d.\n", bytes);
+	OSC_DUMP_GRANT(D_CACHE, cli, "need:%d.\n", bytes);
 
 	rc = osc_reserve_grant(cli, bytes);
 	if (rc < 0)
 		return 0;
 
-	if (cli->cl_dirty + CFS_PAGE_SIZE <= cli->cl_dirty_max &&
-	    cfs_atomic_read(&obd_dirty_pages) + 1 <= obd_max_dirty_pages) {
+	if (cli->cl_dirty + PAGE_CACHE_SIZE <= cli->cl_dirty_max &&
+	    cfs_atomic_read(&obd_unstable_pages) + 1 +
+	    cfs_atomic_read(&obd_dirty_pages) <= obd_max_dirty_pages) {
 		osc_consume_write_grant(cli, &oap->oap_brw_page);
 		if (transient) {
-			cli->cl_dirty_transit += CFS_PAGE_SIZE;
+			cli->cl_dirty_transit += PAGE_CACHE_SIZE;
 			cfs_atomic_inc(&obd_dirty_transit_pages);
 			oap->oap_brw_flags |= OBD_BRW_NOCACHE;
 		}
@@ -1482,7 +1497,7 @@ static int ocw_granted(struct client_obd *cli, struct osc_cache_waiter *ocw)
 {
 	int rc;
 	client_obd_list_lock(&cli->cl_loi_list_lock);
-	rc = cfs_list_empty(&ocw->ocw_entry) || cli->cl_w_in_flight == 0;
+	rc = cfs_list_empty(&ocw->ocw_entry);
 	client_obd_list_unlock(&cli->cl_loi_list_lock);
 	return rc;
 }
@@ -1500,18 +1515,19 @@ static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
 	struct osc_object *osc = oap->oap_obj;
 	struct lov_oinfo  *loi = osc->oo_oinfo;
 	struct osc_cache_waiter ocw;
-	struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
+	struct l_wait_info lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(600), NULL,
+						  LWI_ON_SIGNAL_NOOP, NULL);
 	int rc = -EDQUOT;
 	ENTRY;
 
-	OSC_DUMP_GRANT(cli, "need:%d.\n", bytes);
+	OSC_DUMP_GRANT(D_CACHE, cli, "need:%d.\n", bytes);
 
 	client_obd_list_lock(&cli->cl_loi_list_lock);
 
 	/* force the caller to try sync io.  this can jump the list
 	 * of queued writes and create a discontiguous rpc stream */
 	if (OBD_FAIL_CHECK(OBD_FAIL_OSC_NO_GRANT) ||
-	    cli->cl_dirty_max < CFS_PAGE_SIZE     ||
+	    cli->cl_dirty_max < PAGE_CACHE_SIZE     ||
 	    cli->cl_ar.ar_force_sync || loi->loi_ar.ar_force_sync)
 		GOTO(out, rc = -EDQUOT);
 
@@ -1525,10 +1541,10 @@ static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
 	 * RPC size will be.
 	 * The exiting condition is no avail grants and no dirty pages caching,
 	 * that really means there is no space on the OST. */
-	cfs_waitq_init(&ocw.ocw_waitq);
+	init_waitqueue_head(&ocw.ocw_waitq);
 	ocw.ocw_oap   = oap;
 	ocw.ocw_grant = bytes;
-	if (cli->cl_dirty > 0 || cli->cl_w_in_flight > 0) {
+	while (cli->cl_dirty > 0 || cli->cl_w_in_flight > 0) {
 		cfs_list_add_tail(&ocw.ocw_entry, &cli->cl_cache_waiters);
 		ocw.ocw_rc = 0;
 		client_obd_list_unlock(&cli->cl_loi_list_lock);
@@ -1542,31 +1558,42 @@ static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
 
 		client_obd_list_lock(&cli->cl_loi_list_lock);
 
-		/* l_wait_event is interrupted by signal */
+		/* l_wait_event is interrupted by signal, or timed out */
 		if (rc < 0) {
+			switch (rc) {
+			case -ETIMEDOUT:
+				OSC_DUMP_GRANT(D_ERROR, cli,
+						"try to reserve %d.\n", bytes);
+				osc_extent_tree_dump(D_ERROR, osc);
+				rc = -EDQUOT;
+				break;
+			case -EINTR:
+				/* Ensures restartability - LU-3581 */
+				rc = -ERESTARTSYS;
+				break;
+			default:
+				CDEBUG(D_CACHE, "%s: event for cache space @"
+				       " %p never arrived due to %d\n",
+				       cli->cl_import->imp_obd->obd_name,
+				       &ocw, rc);
+				break;
+			}
 			cfs_list_del_init(&ocw.ocw_entry);
 			GOTO(out, rc);
 		}
 
-		/* If ocw_entry isn't empty, which means it's not waked up
-		 * by osc_wake_cache_waiters(), then the page must not be
-		 * granted yet. */
-		if (!cfs_list_empty(&ocw.ocw_entry)) {
-			rc = -EDQUOT;
-			cfs_list_del_init(&ocw.ocw_entry);
-		} else {
-			rc = ocw.ocw_rc;
-		}
+		LASSERT(cfs_list_empty(&ocw.ocw_entry));
+		rc = ocw.ocw_rc;
 
 		if (rc != -EDQUOT)
 			GOTO(out, rc);
 		if (osc_enter_cache_try(cli, oap, bytes, 0))
-			rc = 0;
+			GOTO(out, rc = 0);
 	}
 	EXIT;
 out:
 	client_obd_list_unlock(&cli->cl_loi_list_lock);
-	OSC_DUMP_GRANT(cli, "returned %d.\n", rc);
+	OSC_DUMP_GRANT(D_CACHE, cli, "returned %d.\n", rc);
 	RETURN(rc);
 }
 
@@ -1578,35 +1605,29 @@ void osc_wake_cache_waiters(struct client_obd *cli)
 
 	ENTRY;
 	cfs_list_for_each_safe(l, tmp, &cli->cl_cache_waiters) {
-		/* if we can't dirty more, we must wait until some is written */
-		if ((cli->cl_dirty + CFS_PAGE_SIZE > cli->cl_dirty_max) ||
-		    (cfs_atomic_read(&obd_dirty_pages) + 1 >
-		     obd_max_dirty_pages)) {
+		ocw = cfs_list_entry(l, struct osc_cache_waiter, ocw_entry);
+		cfs_list_del_init(&ocw->ocw_entry);
+
+		ocw->ocw_rc = -EDQUOT;
+		/* we can't dirty more */
+		if ((cli->cl_dirty + PAGE_CACHE_SIZE > cli->cl_dirty_max) ||
+		    (cfs_atomic_read(&obd_unstable_pages) + 1 +
+		     cfs_atomic_read(&obd_dirty_pages) > obd_max_dirty_pages)) {
 			CDEBUG(D_CACHE, "no dirty room: dirty: %ld "
 			       "osc max %ld, sys max %d\n", cli->cl_dirty,
 			       cli->cl_dirty_max, obd_max_dirty_pages);
-			return;
+			goto wakeup;
 		}
 
-		/* if still dirty cache but no grant wait for pending RPCs that
-		 * may yet return us some grant before doing sync writes */
-		if (cli->cl_w_in_flight && cli->cl_avail_grant < CFS_PAGE_SIZE) {
-			CDEBUG(D_CACHE, "%u BRW writes in flight, no grant\n",
-			       cli->cl_w_in_flight);
-			return;
-		}
-
-		ocw = cfs_list_entry(l, struct osc_cache_waiter, ocw_entry);
-		cfs_list_del_init(&ocw->ocw_entry);
-
 		ocw->ocw_rc = 0;
 		if (!osc_enter_cache_try(cli, ocw->ocw_oap, ocw->ocw_grant, 0))
 			ocw->ocw_rc = -EDQUOT;
 
+wakeup:
 		CDEBUG(D_CACHE, "wake up %p for oap %p, avail grant %ld, %d\n",
 		       ocw, ocw->ocw_oap, cli->cl_avail_grant, ocw->ocw_rc);
 
-		cfs_waitq_signal(&ocw->ocw_waitq);
+		wake_up(&ocw->ocw_waitq);
 	}
 
 	EXIT;
@@ -1759,6 +1780,91 @@ static void osc_process_ar(struct osc_async_rc *ar, __u64 xid,
 		ar->ar_force_sync = 0;
 }
 
+/* Performs "unstable" page accounting. This function balances the
+ * increment operations performed in osc_inc_unstable_pages. It is
+ * registered as the RPC request callback, and is executed when the
+ * bulk RPC is committed on the server. Thus at this point, the pages
+ * involved in the bulk transfer are no longer considered unstable. */
+void osc_dec_unstable_pages(struct ptlrpc_request *req)
+{
+	struct ptlrpc_bulk_desc *desc       = req->rq_bulk;
+	struct client_obd       *cli        = &req->rq_import->imp_obd->u.cli;
+	obd_count                page_count = desc->bd_iov_count;
+	int i;
+
+	/* No unstable page tracking */
+	if (cli->cl_cache == NULL)
+		return;
+
+	LASSERT(page_count >= 0);
+
+	for (i = 0; i < page_count; i++)
+		dec_zone_page_state(desc->bd_iov[i].kiov_page, NR_UNSTABLE_NFS);
+
+	cfs_atomic_sub(page_count, &cli->cl_cache->ccc_unstable_nr);
+	LASSERT(cfs_atomic_read(&cli->cl_cache->ccc_unstable_nr) >= 0);
+
+	cfs_atomic_sub(page_count, &cli->cl_unstable_count);
+	LASSERT(cfs_atomic_read(&cli->cl_unstable_count) >= 0);
+
+	cfs_atomic_sub(page_count, &obd_unstable_pages);
+	LASSERT(cfs_atomic_read(&obd_unstable_pages) >= 0);
+
+	spin_lock(&req->rq_lock);
+	req->rq_committed = 1;
+	req->rq_unstable  = 0;
+	spin_unlock(&req->rq_lock);
+
+	wake_up_all(&cli->cl_cache->ccc_unstable_waitq);
+}
+
+/* "unstable" page accounting. See: osc_dec_unstable_pages. */
+void osc_inc_unstable_pages(struct ptlrpc_request *req)
+{
+	struct ptlrpc_bulk_desc *desc = req->rq_bulk;
+	struct client_obd       *cli  = &req->rq_import->imp_obd->u.cli;
+	obd_count                page_count = desc->bd_iov_count;
+	int i;
+
+	/* No unstable page tracking */
+	if (cli->cl_cache == NULL)
+		return;
+
+	LASSERT(page_count >= 0);
+
+	for (i = 0; i < page_count; i++)
+		inc_zone_page_state(desc->bd_iov[i].kiov_page, NR_UNSTABLE_NFS);
+
+	LASSERT(cfs_atomic_read(&cli->cl_cache->ccc_unstable_nr) >= 0);
+	cfs_atomic_add(page_count, &cli->cl_cache->ccc_unstable_nr);
+
+	LASSERT(cfs_atomic_read(&cli->cl_unstable_count) >= 0);
+	cfs_atomic_add(page_count, &cli->cl_unstable_count);
+
+	LASSERT(cfs_atomic_read(&obd_unstable_pages) >= 0);
+	cfs_atomic_add(page_count, &obd_unstable_pages);
+
+	spin_lock(&req->rq_lock);
+
+	/* If the request has already been committed (i.e. brw_commit
+	 * called via rq_commit_cb), we need to undo the unstable page
+	 * increments we just performed because rq_commit_cb wont be
+	 * called again. Otherwise, just set the commit callback so the
+	 * unstable page accounting is properly updated when the request
+	 * is committed */
+	if (req->rq_committed) {
+		/* Drop lock before calling osc_dec_unstable_pages */
+		spin_unlock(&req->rq_lock);
+		osc_dec_unstable_pages(req);
+		spin_lock(&req->rq_lock);
+	} else {
+		req->rq_unstable  = 1;
+		req->rq_commit_cb = osc_dec_unstable_pages;
+	}
+
+	spin_unlock(&req->rq_lock);
+}
+
 /* this must be called holding the loi list lock to give coverage to exit_cache,
  * async_flag maintenance, and oap_request */
 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
@@ -1770,6 +1876,9 @@ static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
 
 	ENTRY;
 	if (oap->oap_request != NULL) {
+		if (rc == 0)
+			osc_inc_unstable_pages(oap->oap_request);
+
 		xid = ptlrpc_req_xid(oap->oap_request);
 		ptlrpc_req_finished(oap->oap_request);
 		oap->oap_request = NULL;
@@ -1816,7 +1925,7 @@ static int try_to_add_extent_for_io(struct client_obd *cli,
 		RETURN(0);
 
 	cfs_list_for_each_entry(tmp, rpclist, oe_link) {
-		EASSERT(tmp->oe_owner == cfs_current(), tmp);
+		EASSERT(tmp->oe_owner == current, tmp);
 #if 0
 		if (overlapped(tmp, ext)) {
 			OSC_EXTENT_DUMP(D_ERROR, tmp, "overlapped %p.\n", ext);
@@ -1834,7 +1943,7 @@ static int try_to_add_extent_for_io(struct client_obd *cli,
 
 	*pc += ext->oe_nr_pages;
 	cfs_list_move_tail(&ext->oe_link, rpclist);
-	ext->oe_owner = cfs_current();
+	ext->oe_owner = current;
 	RETURN(1);
 }
 
@@ -2075,7 +2184,7 @@ static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli,
 
 	while ((osc = osc_next_obj(cli)) != NULL) {
 		struct cl_object *obj = osc2cl(osc);
-		struct lu_ref_link *link;
+		struct lu_ref_link link;
 
 		OSC_IO_DEBUG(osc, "%lu in flight\n", rpcs_in_flight(cli));
 
@@ -2086,7 +2195,8 @@ static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli,
 
 		cl_object_get(obj);
 		client_obd_list_unlock(&cli->cl_loi_list_lock);
-		link = lu_object_ref_add(&obj->co_lu, "check", cfs_current());
+		lu_object_ref_add_at(&obj->co_lu, &link, "check",
+				     current);
 
 		/* attempt some read/write balancing by alternating between
 		 * reads and writes in an object.  The makes_rpc checks here
@@ -2127,7 +2237,8 @@ static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli,
 		osc_object_unlock(osc);
 
 		osc_list_maint(cli, osc);
-		lu_object_ref_del_at(&obj->co_lu, link, "check", cfs_current());
+		lu_object_ref_del_at(&obj->co_lu, &link, "check",
+				     current);
 		cl_object_put(env, obj);
 
 		client_obd_list_lock(&cli->cl_loi_list_lock);
@@ -2137,23 +2248,24 @@ static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli,
 static int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
 			  struct osc_object *osc, pdl_policy_t pol, int async)
 {
-	int has_rpcs = 1;
 	int rc = 0;
 
-	client_obd_list_lock(&cli->cl_loi_list_lock);
-	if (osc != NULL)
-		has_rpcs = __osc_list_maint(cli, osc);
-	if (has_rpcs) {
-		if (!async) {
-			osc_check_rpcs(env, cli, pol);
-		} else {
-			CDEBUG(D_CACHE, "Queue writeback work for client %p.\n",
-			       cli);
-			LASSERT(cli->cl_writeback_work != NULL);
-			rc = ptlrpcd_queue_work(cli->cl_writeback_work);
-		}
+	if (osc != NULL && osc_list_maint(cli, osc) == 0)
+		return 0;
+
+	if (!async) {
+		/* disable osc_lru_shrink() temporarily to avoid
+		 * potential stack overrun problem. LU-2859 */
+		cfs_atomic_inc(&cli->cl_lru_shrinkers);
+		client_obd_list_lock(&cli->cl_loi_list_lock);
+		osc_check_rpcs(env, cli, pol);
+		client_obd_list_unlock(&cli->cl_loi_list_lock);
+		cfs_atomic_dec(&cli->cl_lru_shrinkers);
+	} else {
+		CDEBUG(D_CACHE, "Queue writeback work for client %p.\n", cli);
+		LASSERT(cli->cl_writeback_work != NULL);
+		rc = ptlrpcd_queue_work(cli->cl_writeback_work);
 	}
-	client_obd_list_unlock(&cli->cl_loi_list_lock);
 	return rc;
 }
 
@@ -2171,7 +2283,7 @@ void osc_io_unplug(const struct lu_env *env, struct client_obd *cli,
 }
 
 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
-			cfs_page_t *page, loff_t offset)
+			struct page *page, loff_t offset)
 {
 	struct obd_export     *exp = osc_export(osc);
 	struct osc_async_page *oap = &ops->ops_oap;
@@ -2255,9 +2367,14 @@ int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
 			RETURN(rc);
 	}
 
+	if (osc_over_unstable_soft_limit(cli))
+		brw_flags |= OBD_BRW_SOFT_SYNC;
+
 	oap->oap_cmd = cmd;
 	oap->oap_page_off = ops->ops_from;
 	oap->oap_count = ops->ops_to - ops->ops_from;
+	/* No need to hold a lock here,
+	 * since this page is not in any list yet. */
 	oap->oap_async_flags = 0;
 	oap->oap_brw_flags = brw_flags;
 
@@ -2452,7 +2569,7 @@ int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
 	oap->oap_async_flags |= ASYNC_READY|ASYNC_URGENT;
 	spin_unlock(&oap->oap_lock);
 
-	if (cfs_memory_pressure_get())
+	if (memory_pressure_get())
 		ext->oe_memalloc = 1;
 
 	ext->oe_urgent = 1;
@@ -2709,7 +2826,7 @@ again:
 		 * should take care of it. */
 		rc = osc_extent_wait(env, waiting, OES_INV);
 		if (rc < 0)
-			OSC_EXTENT_DUMP(D_CACHE, ext, "wait error: %d.\n", rc);
+			OSC_EXTENT_DUMP(D_CACHE, waiting, "error: %d.\n", rc);
 
 		osc_extent_put(env, waiting);
 		waiting = NULL;
@@ -2858,7 +2975,7 @@ int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
 				EASSERT(ext->oe_start >= start &&
 					ext->oe_max_end <= end, ext);
 				osc_extent_state_set(ext, OES_LOCKING);
-				ext->oe_owner = cfs_current();
+				ext->oe_owner = current;
 				cfs_list_move_tail(&ext->oe_link,
 						   &discard_list);
 				osc_update_pending(obj, OBD_BRW_WRITE,
@@ -2919,7 +3036,7 @@ int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
 			result = rc;
 	}
 
-	OSC_IO_DEBUG(obj, "cache page out.\n");
+	OSC_IO_DEBUG(obj, "pageout [%lu, %lu], %d.\n", start, end, result);
 	RETURN(result);
 }