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LU-8460 osc: max_pages_per_rpc should be chunk size aligned
[fs/lustre-release.git] / lustre / osc / osc_cache.c
index eb3084f..27a034e 100644 (file)
@@ -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, 2013, Intel Corporation.
+ * Copyright (c) 2012, 2015, Intel Corporation.
  *
  */
 /*
@@ -48,7 +48,7 @@ static int extent_debug; /* set it to be true for more debug */
 
 static void osc_update_pending(struct osc_object *obj, int cmd, int delta);
 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
-                          int state);
+                          enum osc_extent_state state);
 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
                              struct osc_async_page *oap, int sent, int rc);
 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
@@ -58,13 +58,16 @@ static int osc_refresh_count(const struct lu_env *env,
 static int osc_io_unplug_async(const struct lu_env *env,
                               struct client_obd *cli, struct osc_object *osc);
 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
-                          unsigned int lost_grant);
+                          unsigned int lost_grant, unsigned int dirty_grant);
 
 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
                                  const char *func, int line);
 #define osc_extent_tree_dump(lvl, obj) \
        osc_extent_tree_dump0(lvl, obj, __func__, __LINE__)
 
+static void osc_unreserve_grant(struct client_obd *cli, unsigned int reserved,
+                               unsigned int unused);
+
 /** \addtogroup osc
  *  @{
  */
@@ -76,6 +79,8 @@ static inline char *ext_flags(struct osc_extent *ext, char *flags)
        *buf++ = ext->oe_rw ? 'r' : 'w';
        if (ext->oe_intree)
                *buf++ = 'i';
+       if (ext->oe_sync)
+               *buf++ = 'S';
        if (ext->oe_srvlock)
                *buf++ = 's';
        if (ext->oe_hp)
@@ -102,28 +107,32 @@ static inline char list_empty_marker(struct list_head *list)
 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);                            \
-       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 ----- */                         \
-               __ext, EXTPARA(__ext),                                  \
-               /* ----- part 1 ----- */                                \
-               atomic_read(&__ext->oe_refc),                           \
-               atomic_read(&__ext->oe_users),                          \
-               list_empty_marker(&__ext->oe_link),                     \
-               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),                    \
-               waitqueue_active(&__ext->oe_waitq) ? '+' : '-',         \
-               __ext->oe_osclock, __ext->oe_mppr, __ext->oe_owner,     \
-               /* ----- part 4 ----- */                                \
-               ## __VA_ARGS__);                                        \
+#define OSC_EXTENT_DUMP(lvl, extent, fmt, ...) do {                          \
+       struct osc_extent *__ext = (extent);                                  \
+       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 ----- */                               \
+               __ext, EXTPARA(__ext),                                        \
+               /* ----- part 1 ----- */                                      \
+               atomic_read(&__ext->oe_refc),                         \
+               atomic_read(&__ext->oe_users),                        \
+               list_empty_marker(&__ext->oe_link),                           \
+               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),                          \
+               waitqueue_active(&__ext->oe_waitq) ? '+' : '-',               \
+               __ext->oe_dlmlock, __ext->oe_mppr, __ext->oe_owner,           \
+               /* ----- part 4 ----- */                                      \
+               ## __VA_ARGS__);                                              \
+       if (lvl == D_ERROR && __ext->oe_dlmlock != NULL)                      \
+               LDLM_ERROR(__ext->oe_dlmlock, "extent: %p", __ext);           \
+       else                                                                  \
+               LDLM_DEBUG(__ext->oe_dlmlock, "extent: %p", __ext);           \
 } while (0)
 
 #undef EASSERTF
@@ -175,7 +184,7 @@ static int osc_extent_sanity_check0(struct osc_extent *ext,
 {
        struct osc_object *obj = ext->oe_obj;
        struct osc_async_page *oap;
-       int page_count;
+       size_t page_count;
        int rc = 0;
 
        if (!osc_object_is_locked(obj))
@@ -217,15 +226,19 @@ static int osc_extent_sanity_check0(struct osc_extent *ext,
        if (ext->oe_max_end < ext->oe_end || ext->oe_end < ext->oe_start)
                GOTO(out, rc = 80);
 
-       if (ext->oe_osclock == NULL && ext->oe_grants > 0)
+       if (ext->oe_sync && ext->oe_grants > 0)
                GOTO(out, rc = 90);
 
-       if (ext->oe_osclock) {
-               struct cl_lock_descr *descr;
-               descr = &ext->oe_osclock->cll_descr;
-               if (!(descr->cld_start <= ext->oe_start &&
-                     descr->cld_end >= ext->oe_max_end))
+       if (ext->oe_dlmlock != NULL && !ldlm_is_failed(ext->oe_dlmlock)) {
+               struct ldlm_extent *extent;
+
+               extent = &ext->oe_dlmlock->l_policy_data.l_extent;
+               if (!(extent->start <= cl_offset(osc2cl(obj), ext->oe_start) &&
+                     extent->end   >= cl_offset(osc2cl(obj), ext->oe_max_end)))
                        GOTO(out, rc = 100);
+
+               if (!(ext->oe_dlmlock->l_granted_mode & (LCK_PW | LCK_GROUP)))
+                       GOTO(out, rc = 102);
        }
 
        if (ext->oe_nr_pages > ext->oe_mppr)
@@ -309,19 +322,20 @@ static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
 {
        struct osc_extent *ext;
 
-       OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, GFP_IOFS);
+       OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, GFP_NOFS);
        if (ext == NULL)
                return NULL;
 
        RB_CLEAR_NODE(&ext->oe_node);
        ext->oe_obj = obj;
+       cl_object_get(osc2cl(obj));
        atomic_set(&ext->oe_refc, 1);
        atomic_set(&ext->oe_users, 0);
        INIT_LIST_HEAD(&ext->oe_link);
        ext->oe_state = OES_INV;
        INIT_LIST_HEAD(&ext->oe_pages);
        init_waitqueue_head(&ext->oe_waitq);
-       ext->oe_osclock = NULL;
+       ext->oe_dlmlock = NULL;
 
        return ext;
 }
@@ -347,10 +361,13 @@ static void osc_extent_put(const struct lu_env *env, struct osc_extent *ext)
                LASSERT(ext->oe_state == OES_INV);
                LASSERT(!ext->oe_intree);
 
-               if (ext->oe_osclock) {
-                       cl_lock_put(env, ext->oe_osclock);
-                       ext->oe_osclock = NULL;
+               if (ext->oe_dlmlock != NULL) {
+                       lu_ref_add(&ext->oe_dlmlock->l_reference,
+                                  "osc_extent", ext);
+                       LDLM_LOCK_PUT(ext->oe_dlmlock);
+                       ext->oe_dlmlock = NULL;
                }
+               cl_object_put(env, osc2cl(ext->oe_obj));
                osc_extent_free(ext);
        }
 }
@@ -483,15 +500,16 @@ static void osc_extent_remove(struct osc_extent *ext)
 
 /**
  * This function is used to merge extents to get better performance. It checks
- * if @cur and @victim are contiguous at chunk level.
+ * if @cur and @victim are contiguous at block level.
  */
 static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
                            struct osc_extent *victim)
 {
-       struct osc_object *obj = cur->oe_obj;
-       pgoff_t chunk_start;
-       pgoff_t chunk_end;
-       int ppc_bits;
+       struct osc_object       *obj = cur->oe_obj;
+       struct client_obd       *cli = osc_cli(obj);
+       pgoff_t                  chunk_start;
+       pgoff_t                  chunk_end;
+       int                      ppc_bits;
 
        LASSERT(cur->oe_state == OES_CACHE);
        LASSERT(osc_object_is_locked(obj));
@@ -504,7 +522,7 @@ static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
        if (cur->oe_max_end != victim->oe_max_end)
                return -ERANGE;
 
-       LASSERT(cur->oe_osclock == victim->oe_osclock);
+       LASSERT(cur->oe_dlmlock == victim->oe_dlmlock);
        ppc_bits = osc_cli(obj)->cl_chunkbits - PAGE_CACHE_SHIFT;
        chunk_start = cur->oe_start >> ppc_bits;
        chunk_end   = cur->oe_end   >> ppc_bits;
@@ -512,11 +530,18 @@ static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
            chunk_end + 1 != victim->oe_start >> ppc_bits)
                return -ERANGE;
 
+       /* overall extent size should not exceed the max supported limit
+        * reported by the server */
+       if (cur->oe_end - cur->oe_start + 1 +
+           victim->oe_end - victim->oe_start + 1 > cli->cl_max_extent_pages)
+               return -ERANGE;
+
        OSC_EXTENT_DUMP(D_CACHE, victim, "will be merged by %p.\n", cur);
 
        cur->oe_start     = min(cur->oe_start, victim->oe_start);
        cur->oe_end       = max(cur->oe_end,   victim->oe_end);
-       cur->oe_grants   += victim->oe_grants;
+       /* per-extent tax should be accounted only once for the whole extent */
+       cur->oe_grants   += victim->oe_grants - cli->cl_grant_extent_tax;
        cur->oe_nr_pages += victim->oe_nr_pages;
        /* only the following bits are needed to merge */
        cur->oe_urgent   |= victim->oe_urgent;
@@ -539,6 +564,7 @@ static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
 int osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
 {
        struct osc_object *obj = ext->oe_obj;
+       struct client_obd *cli = osc_cli(obj);
        int rc = 0;
        ENTRY;
 
@@ -555,13 +581,19 @@ int osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
                        osc_extent_state_set(ext, OES_TRUNC);
                        ext->oe_trunc_pending = 0;
                } else {
+                       int grant = 0;
+
                        osc_extent_state_set(ext, OES_CACHE);
                        osc_update_pending(obj, OBD_BRW_WRITE,
                                           ext->oe_nr_pages);
 
                        /* try to merge the previous and next extent. */
-                       osc_extent_merge(env, ext, prev_extent(ext));
-                       osc_extent_merge(env, ext, next_extent(ext));
+                       if (osc_extent_merge(env, ext, prev_extent(ext)) == 0)
+                               grant += cli->cl_grant_extent_tax;
+                       if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
+                               grant += cli->cl_grant_extent_tax;
+                       if (grant > 0)
+                               osc_unreserve_grant(cli, 0, grant);
 
                        if (ext->oe_urgent)
                                list_move_tail(&ext->oe_link,
@@ -569,7 +601,7 @@ int osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
                }
                osc_object_unlock(obj);
 
-               osc_io_unplug_async(env, osc_cli(obj), obj);
+               osc_io_unplug_async(env, cli, obj);
        }
        osc_extent_put(env, ext);
        RETURN(rc);
@@ -584,23 +616,23 @@ static inline int overlapped(struct osc_extent *ex1, struct osc_extent *ex2)
  * Find or create an extent which includes @index, core function to manage
  * extent tree.
  */
-struct osc_extent *osc_extent_find(const struct lu_env *env,
-                                  struct osc_object *obj, pgoff_t index,
-                                  int *grants)
-
+static struct osc_extent *osc_extent_find(const struct lu_env *env,
+                                         struct osc_object *obj, pgoff_t index,
+                                         unsigned int *grants)
 {
        struct client_obd *cli = osc_cli(obj);
-       struct cl_lock    *lock;
+       struct osc_lock   *olck;
+       struct cl_lock_descr *descr;
        struct osc_extent *cur;
        struct osc_extent *ext;
        struct osc_extent *conflict = NULL;
        struct osc_extent *found = NULL;
        pgoff_t    chunk;
        pgoff_t    max_end;
-       int        max_pages; /* max_pages_per_rpc */
-       int        chunksize;
+       unsigned int max_pages; /* max_pages_per_rpc */
+       unsigned int chunksize;
        int        ppc_bits; /* pages per chunk bits */
-       int        chunk_mask;
+       pgoff_t    chunk_mask;
        int        rc;
        ENTRY;
 
@@ -608,37 +640,49 @@ struct osc_extent *osc_extent_find(const struct lu_env *env,
        if (cur == NULL)
                RETURN(ERR_PTR(-ENOMEM));
 
-       lock = cl_lock_at_pgoff(env, osc2cl(obj), index, NULL, 1, 0);
-       LASSERT(lock != NULL);
-       LASSERT(lock->cll_descr.cld_mode >= CLM_WRITE);
+       olck = osc_env_io(env)->oi_write_osclock;
+       LASSERTF(olck != NULL, "page %lu is not covered by lock\n", index);
+       LASSERT(olck->ols_state == OLS_GRANTED);
+
+       descr = &olck->ols_cl.cls_lock->cll_descr;
+       LASSERT(descr->cld_mode >= CLM_WRITE);
 
-       LASSERT(cli->cl_chunkbits >= PAGE_CACHE_SHIFT);
-       ppc_bits   = cli->cl_chunkbits - PAGE_CACHE_SHIFT;
+       LASSERTF(cli->cl_chunkbits >= PAGE_SHIFT,
+                "chunkbits: %u\n", cli->cl_chunkbits);
+       ppc_bits   = cli->cl_chunkbits - PAGE_SHIFT;
        chunk_mask = ~((1 << ppc_bits) - 1);
        chunksize  = 1 << cli->cl_chunkbits;
        chunk      = index >> ppc_bits;
 
-       /* align end to rpc edge, rpc size may not be a power 2 integer. */
+       /* align end to RPC edge. */
        max_pages = cli->cl_max_pages_per_rpc;
-       LASSERT((max_pages & ~chunk_mask) == 0);
+       if ((max_pages & ~chunk_mask) != 0) {
+               CERROR("max_pages: %#x chunkbits: %u chunk_mask: %#lx\n",
+                      max_pages, cli->cl_chunkbits, chunk_mask);
+               RETURN(ERR_PTR(-EINVAL));
+       }
        max_end = index - (index % max_pages) + max_pages - 1;
-       max_end = min_t(pgoff_t, max_end, lock->cll_descr.cld_end);
+       max_end = min_t(pgoff_t, max_end, descr->cld_end);
 
        /* initialize new extent by parameters so far */
        cur->oe_max_end = max_end;
        cur->oe_start   = index & chunk_mask;
        cur->oe_end     = ((index + ~chunk_mask + 1) & chunk_mask) - 1;
-       if (cur->oe_start < lock->cll_descr.cld_start)
-               cur->oe_start = lock->cll_descr.cld_start;
+       if (cur->oe_start < descr->cld_start)
+               cur->oe_start = descr->cld_start;
        if (cur->oe_end > max_end)
                cur->oe_end = max_end;
-       cur->oe_osclock = lock;
        cur->oe_grants  = 0;
        cur->oe_mppr    = max_pages;
+       if (olck->ols_dlmlock != NULL) {
+               LASSERT(olck->ols_hold);
+               cur->oe_dlmlock = LDLM_LOCK_GET(olck->ols_dlmlock);
+               lu_ref_add(&olck->ols_dlmlock->l_reference, "osc_extent", cur);
+       }
 
        /* grants has been allocated by caller */
-       LASSERTF(*grants >= chunksize + cli->cl_extent_tax,
-                "%u/%u/%u.\n", *grants, chunksize, cli->cl_extent_tax);
+       LASSERTF(*grants >= chunksize + cli->cl_grant_extent_tax,
+                "%u/%u/%u.\n", *grants, chunksize, cli->cl_grant_extent_tax);
        LASSERTF((max_end - cur->oe_start) < max_pages, EXTSTR"\n",
                 EXTPARA(cur));
 
@@ -648,15 +692,15 @@ restart:
        if (ext == NULL)
                ext = first_extent(obj);
        while (ext != NULL) {
-               loff_t ext_chk_start = ext->oe_start >> ppc_bits;
-               loff_t ext_chk_end   = ext->oe_end   >> ppc_bits;
+               pgoff_t ext_chk_start = ext->oe_start >> ppc_bits;
+               pgoff_t ext_chk_end   = ext->oe_end   >> ppc_bits;
 
                LASSERT(sanity_check_nolock(ext) == 0);
                if (chunk > ext_chk_end + 1)
                        break;
 
                /* if covering by different locks, no chance to match */
-               if (lock != ext->oe_osclock) {
+               if (olck->ols_dlmlock != ext->oe_dlmlock) {
                        EASSERTF(!overlapped(ext, cur), ext,
                                 EXTSTR"\n", EXTPARA(cur));
 
@@ -711,6 +755,13 @@ restart:
                        continue;
                }
 
+               /* check whether maximum extent size will be hit */
+               if ((ext_chk_end - ext_chk_start + 1 + 1) << ppc_bits >
+                   cli->cl_max_extent_pages) {
+                       ext = next_extent(ext);
+                       continue;
+               }
+
                /* it's required that an extent must be contiguous at chunk
                 * level so that we know the whole extent is covered by grant
                 * (the pages in the extent are NOT required to be contiguous).
@@ -738,7 +789,7 @@ restart:
                         * in a gap */
                        if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
                                /* we can save extent tax from next extent */
-                               *grants += cli->cl_extent_tax;
+                               *grants += cli->cl_grant_extent_tax;
 
                        found = osc_extent_hold(ext);
                }
@@ -752,14 +803,14 @@ restart:
        if (found != NULL) {
                LASSERT(conflict == NULL);
                if (!IS_ERR(found)) {
-                       LASSERT(found->oe_osclock == cur->oe_osclock);
+                       LASSERT(found->oe_dlmlock == cur->oe_dlmlock);
                        OSC_EXTENT_DUMP(D_CACHE, found,
                                        "found caching ext for %lu.\n", index);
                }
        } else if (conflict == NULL) {
                /* create a new extent */
                EASSERT(osc_extent_is_overlapped(obj, cur) == 0, cur);
-               cur->oe_grants = chunksize + cli->cl_extent_tax;
+               cur->oe_grants = chunksize + cli->cl_grant_extent_tax;
                *grants -= cur->oe_grants;
                LASSERT(*grants >= 0);
 
@@ -767,7 +818,7 @@ restart:
                found = osc_extent_hold(cur);
                osc_extent_insert(obj, cur);
                OSC_EXTENT_DUMP(D_CACHE, cur, "add into tree %lu/%lu.\n",
-                               index, lock->cll_descr.cld_end);
+                               index, descr->cld_end);
        }
        osc_object_unlock(obj);
 
@@ -804,7 +855,7 @@ int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
        int nr_pages = ext->oe_nr_pages;
        int lost_grant = 0;
        int blocksize = cli->cl_import->imp_obd->obd_osfs.os_bsize ? : 4096;
-       __u64 last_off = 0;
+       loff_t last_off = 0;
        int last_count = -1;
        ENTRY;
 
@@ -835,7 +886,7 @@ int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
                /* 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. */
-               int offset = last_off & ~CFS_PAGE_MASK;
+               int offset = last_off & ~PAGE_MASK;
                int count = last_count + (offset & (blocksize - 1));
                int end = (offset + last_count) & (blocksize - 1);
                if (end)
@@ -844,7 +895,7 @@ int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
                lost_grant = PAGE_CACHE_SIZE - count;
        }
        if (ext->oe_grants > 0)
-               osc_free_grant(cli, nr_pages, lost_grant);
+               osc_free_grant(cli, nr_pages, lost_grant, ext->oe_grants);
 
        osc_extent_remove(ext);
        /* put the refcount for RPC */
@@ -852,7 +903,7 @@ int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
        RETURN(0);
 }
 
-static int extent_wait_cb(struct osc_extent *ext, int state)
+static int extent_wait_cb(struct osc_extent *ext, enum osc_extent_state state)
 {
        int ret;
 
@@ -867,7 +918,7 @@ static int extent_wait_cb(struct osc_extent *ext, int state)
  * Wait for the extent's state to become @state.
  */
 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
-                          int state)
+                          enum osc_extent_state state)
 {
        struct osc_object *obj = ext->oe_obj;
        struct l_wait_info lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(600), NULL,
@@ -896,8 +947,8 @@ static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
        rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state), &lwi);
        if (rc == -ETIMEDOUT) {
                OSC_EXTENT_DUMP(D_ERROR, ext,
-                       "%s: wait ext to %d timedout, recovery in progress?\n",
-                       osc_export(obj)->exp_obd->obd_name, state);
+                       "%s: wait ext to %u timedout, recovery in progress?\n",
+                       cli_name(osc_cli(obj)), state);
 
                lwi = LWI_INTR(NULL, NULL);
                rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state),
@@ -915,7 +966,6 @@ static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
 static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
                                bool partial)
 {
-       struct cl_env_nest     nest;
        struct lu_env         *env;
        struct cl_io          *io;
        struct osc_object     *obj = ext->oe_obj;
@@ -929,6 +979,7 @@ static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
        int                    grants   = 0;
        int                    nr_pages = 0;
        int                    rc       = 0;
+       __u16                  refcheck;
        ENTRY;
 
        LASSERT(sanity_check(ext) == 0);
@@ -938,14 +989,15 @@ static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
        /* Request new lu_env.
         * We can't use that env from osc_cache_truncate_start() because
         * it's from lov_io_sub and not fully initialized. */
-       env = cl_env_nested_get(&nest);
+       env = cl_env_get(&refcheck);
        io  = &osc_env_info(env)->oti_io;
        io->ci_obj = cl_object_top(osc2cl(obj));
+       io->ci_ignore_layout = 1;
        rc = cl_io_init(env, io, CIT_MISC, io->ci_obj);
        if (rc < 0)
                GOTO(out, rc);
 
-       /* discard all pages with index greater then trunc_index */
+       /* discard all pages with index greater than trunc_index */
        list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
                                     oap_pending_item) {
                pgoff_t index = osc_index(oap2osc(oap));
@@ -1019,11 +1071,11 @@ static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
        osc_object_unlock(obj);
 
        if (grants > 0 || nr_pages > 0)
-               osc_free_grant(cli, nr_pages, grants);
+               osc_free_grant(cli, nr_pages, grants, grants);
 
 out:
        cl_io_fini(env, io);
-       cl_env_nested_put(&nest, env);
+       cl_env_put(env, &refcheck);
        RETURN(rc);
 }
 
@@ -1037,7 +1089,7 @@ static int osc_extent_make_ready(const struct lu_env *env,
        struct osc_async_page *oap;
        struct osc_async_page *last = NULL;
        struct osc_object *obj = ext->oe_obj;
-       int page_count = 0;
+       unsigned int page_count = 0;
        int rc;
        ENTRY;
 
@@ -1078,9 +1130,10 @@ static int osc_extent_make_ready(const struct lu_env *env,
        /* the last page is the only one we need to refresh its count by
         * the size of file. */
        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 <= PAGE_CACHE_SIZE);
+               int last_oap_count = osc_refresh_count(env, last, OBD_BRW_WRITE);
+               LASSERT(last_oap_count > 0);
+               LASSERT(last->oap_page_off + last_oap_count <= PAGE_CACHE_SIZE);
+               last->oap_count = last_oap_count;
                spin_lock(&last->oap_lock);
                last->oap_async_flags |= ASYNC_COUNT_STABLE;
                spin_unlock(&last->oap_lock);
@@ -1111,7 +1164,8 @@ static int osc_extent_make_ready(const struct lu_env *env,
  * called to expand the extent for the same IO. To expand the extent, the
  * page index must be in the same or next chunk of ext->oe_end.
  */
-static int osc_extent_expand(struct osc_extent *ext, pgoff_t index, int *grants)
+static int osc_extent_expand(struct osc_extent *ext, pgoff_t index,
+                            unsigned int *grants)
 {
        struct osc_object *obj = ext->oe_obj;
        struct client_obd *cli = osc_cli(obj);
@@ -1120,7 +1174,7 @@ static int osc_extent_expand(struct osc_extent *ext, pgoff_t index, int *grants)
        pgoff_t chunk = index >> ppc_bits;
        pgoff_t end_chunk;
        pgoff_t end_index;
-       int chunksize = 1 << cli->cl_chunkbits;
+       unsigned int chunksize = 1 << cli->cl_chunkbits;
        int rc = 0;
        ENTRY;
 
@@ -1135,9 +1189,14 @@ static int osc_extent_expand(struct osc_extent *ext, pgoff_t index, int *grants)
                GOTO(out, rc = 0);
 
        LASSERT(end_chunk + 1 == chunk);
+
        /* try to expand this extent to cover @index */
        end_index = min(ext->oe_max_end, ((chunk + 1) << ppc_bits) - 1);
 
+       /* don't go over the maximum extent size reported by server */
+       if (end_index - ext->oe_start + 1 > cli->cl_max_extent_pages)
+               GOTO(out, rc = -ERANGE);
+
        next = next_extent(ext);
        if (next != NULL && next->oe_start <= end_index)
                /* complex mode - overlapped with the next extent,
@@ -1258,7 +1317,6 @@ static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
 {
        struct osc_page   *opg  = oap2osc_page(oap);
        struct cl_page    *page = oap2cl_page(oap);
-       struct osc_object *obj  = cl2osc(opg->ops_cl.cpl_obj);
        enum cl_req_type   crt;
        int srvlock;
 
@@ -1271,25 +1329,10 @@ static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
                "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
        LASSERT(opg->ops_transfer_pinned);
 
-       /*
-        * page->cp_req can be NULL if io submission failed before
-        * cl_req was allocated.
-        */
-       if (page->cp_req != NULL)
-               cl_req_page_done(env, page);
-       LASSERT(page->cp_req == NULL);
-
        crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE;
        /* Clear opg->ops_transfer_pinned before VM lock is released. */
        opg->ops_transfer_pinned = 0;
 
-       spin_lock(&obj->oo_seatbelt);
-       LASSERT(opg->ops_submitter != NULL);
-       LASSERT(!list_empty(&opg->ops_inflight));
-       list_del_init(&opg->ops_inflight);
-       opg->ops_submitter = NULL;
-       spin_unlock(&obj->oo_seatbelt);
-
        opg->ops_submit_time = 0;
        srvlock = oap->oap_brw_flags & OBD_BRW_SRVLOCK;
 
@@ -1297,7 +1340,7 @@ static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
        if (rc == 0 && srvlock) {
                struct lu_device *ld    = opg->ops_cl.cpl_obj->co_lu.lo_dev;
                struct osc_stats *stats = &lu2osc_dev(ld)->od_stats;
-               int bytes = oap->oap_count;
+               size_t bytes = oap->oap_count;
 
                if (crt == CRT_READ)
                        stats->os_lockless_reads += bytes;
@@ -1313,22 +1356,25 @@ static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
        lu_ref_del(&page->cp_reference, "transfer", page);
 
        cl_page_completion(env, page, crt, rc);
+       cl_page_put(env, page);
 
        RETURN(0);
 }
 
 #define OSC_DUMP_GRANT(lvl, cli, fmt, args...) do {                    \
        struct client_obd *__tmp = (cli);                               \
-       CDEBUG(lvl, "%s: grant { dirty: %ld/%ld dirty_pages: %d/%d "    \
-              "dropped: %ld avail: %ld, reserved: %ld, flight: %d }"   \
-              "lru {in list: %d, left: %d, waiters: %d }" fmt "\n",    \
-              __tmp->cl_import->imp_obd->obd_name,                     \
+       CDEBUG(lvl, "%s: grant { dirty: %ld/%ld dirty_pages: %ld/%lu "  \
+              "dropped: %ld avail: %ld, dirty_grant: %ld, "            \
+              "reserved: %ld, flight: %d } lru {in list: %ld, "        \
+              "left: %ld, waiters: %d }" fmt "\n",                     \
+              cli_name(__tmp),                                         \
               __tmp->cl_dirty_pages, __tmp->cl_dirty_max_pages,        \
-              atomic_read(&obd_dirty_pages), obd_max_dirty_pages,      \
+              atomic_long_read(&obd_dirty_pages), obd_max_dirty_pages, \
               __tmp->cl_lost_grant, __tmp->cl_avail_grant,             \
+              __tmp->cl_dirty_grant,                                   \
               __tmp->cl_reserved_grant, __tmp->cl_w_in_flight,         \
-              atomic_read(&__tmp->cl_lru_in_list),                     \
-              atomic_read(&__tmp->cl_lru_busy),                        \
+              atomic_long_read(&__tmp->cl_lru_in_list),                \
+              atomic_long_read(&__tmp->cl_lru_busy),                   \
               atomic_read(&__tmp->cl_lru_shrinkers), ##args);          \
 } while (0)
 
@@ -1336,9 +1382,9 @@ static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
 static void osc_consume_write_grant(struct client_obd *cli,
                                    struct brw_page *pga)
 {
-       assert_spin_locked(&cli->cl_loi_list_lock.lock);
+       assert_spin_locked(&cli->cl_loi_list_lock);
        LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT));
-       atomic_inc(&obd_dirty_pages);
+       atomic_long_inc(&obd_dirty_pages);
        cli->cl_dirty_pages++;
        pga->flag |= OBD_BRW_FROM_GRANT;
        CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n",
@@ -1353,18 +1399,18 @@ static void osc_release_write_grant(struct client_obd *cli,
 {
        ENTRY;
 
-       assert_spin_locked(&cli->cl_loi_list_lock.lock);
+       assert_spin_locked(&cli->cl_loi_list_lock);
        if (!(pga->flag & OBD_BRW_FROM_GRANT)) {
                EXIT;
                return;
        }
 
        pga->flag &= ~OBD_BRW_FROM_GRANT;
-       atomic_dec(&obd_dirty_pages);
+       atomic_long_dec(&obd_dirty_pages);
        cli->cl_dirty_pages--;
        if (pga->flag & OBD_BRW_NOCACHE) {
                pga->flag &= ~OBD_BRW_NOCACHE;
-               atomic_dec(&obd_dirty_transit_pages);
+               atomic_long_dec(&obd_dirty_transit_pages);
                cli->cl_dirty_transit--;
        }
        EXIT;
@@ -1399,19 +1445,21 @@ static void __osc_unreserve_grant(struct client_obd *cli,
        if (unused > reserved) {
                cli->cl_avail_grant += reserved;
                cli->cl_lost_grant  += unused - reserved;
+               cli->cl_dirty_grant -= unused - reserved;
        } else {
                cli->cl_avail_grant += unused;
+               cli->cl_dirty_grant += reserved - unused;
        }
 }
 
-void osc_unreserve_grant(struct client_obd *cli,
-                        unsigned int reserved, unsigned int unused)
+static void osc_unreserve_grant(struct client_obd *cli,
+                               unsigned int reserved, unsigned int unused)
 {
-       client_obd_list_lock(&cli->cl_loi_list_lock);
+       spin_lock(&cli->cl_loi_list_lock);
        __osc_unreserve_grant(cli, reserved, unused);
        if (unused > 0)
                osc_wake_cache_waiters(cli);
-       client_obd_list_unlock(&cli->cl_loi_list_lock);
+       spin_unlock(&cli->cl_loi_list_lock);
 }
 
 /**
@@ -1428,14 +1476,17 @@ void osc_unreserve_grant(struct client_obd *cli,
  *    See filter_grant_check() for details.
  */
 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
-                          unsigned int lost_grant)
+                          unsigned int lost_grant, unsigned int dirty_grant)
 {
-       int grant = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
+       unsigned long grant;
+
+       grant = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
 
-       client_obd_list_lock(&cli->cl_loi_list_lock);
-       atomic_sub(nr_pages, &obd_dirty_pages);
+       spin_lock(&cli->cl_loi_list_lock);
+       atomic_long_sub(nr_pages, &obd_dirty_pages);
        cli->cl_dirty_pages -= nr_pages;
        cli->cl_lost_grant += lost_grant;
+       cli->cl_dirty_grant -= dirty_grant;
        if (cli->cl_avail_grant < grant && cli->cl_lost_grant >= grant) {
                /* borrow some grant from truncate to avoid the case that
                 * truncate uses up all avail grant */
@@ -1443,10 +1494,11 @@ static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
                cli->cl_avail_grant += grant;
        }
        osc_wake_cache_waiters(cli);
-       client_obd_list_unlock(&cli->cl_loi_list_lock);
-       CDEBUG(D_CACHE, "lost %u grant: %lu avail: %lu dirty: %lu\n",
+       spin_unlock(&cli->cl_loi_list_lock);
+       CDEBUG(D_CACHE, "lost %u grant: %lu avail: %lu dirty: %lu/%lu\n",
               lost_grant, cli->cl_lost_grant,
-              cli->cl_avail_grant, cli->cl_dirty_pages << PAGE_CACHE_SHIFT);
+              cli->cl_avail_grant, cli->cl_dirty_pages << PAGE_CACHE_SHIFT,
+              cli->cl_dirty_grant);
 }
 
 /**
@@ -1455,9 +1507,9 @@ static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
  */
 static void osc_exit_cache(struct client_obd *cli, struct osc_async_page *oap)
 {
-       client_obd_list_lock(&cli->cl_loi_list_lock);
+       spin_lock(&cli->cl_loi_list_lock);
        osc_release_write_grant(cli, &oap->oap_brw_page);
-       client_obd_list_unlock(&cli->cl_loi_list_lock);
+       spin_unlock(&cli->cl_loi_list_lock);
 }
 
 /**
@@ -1470,18 +1522,18 @@ static int osc_enter_cache_try(struct client_obd *cli,
 {
        int rc;
 
-       OSC_DUMP_GRANT(D_CACHE, cli, "need:%d", 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_pages < cli->cl_dirty_max_pages &&
-           1 + atomic_read(&obd_dirty_pages) <= obd_max_dirty_pages) {
+           1 + atomic_long_read(&obd_dirty_pages) <= obd_max_dirty_pages) {
                osc_consume_write_grant(cli, &oap->oap_brw_page);
                if (transient) {
                        cli->cl_dirty_transit++;
-                       atomic_inc(&obd_dirty_transit_pages);
+                       atomic_long_inc(&obd_dirty_transit_pages);
                        oap->oap_brw_flags |= OBD_BRW_NOCACHE;
                }
                rc = 1;
@@ -1495,9 +1547,9 @@ static int osc_enter_cache_try(struct client_obd *cli,
 static int ocw_granted(struct client_obd *cli, struct osc_cache_waiter *ocw)
 {
        int rc;
-       client_obd_list_lock(&cli->cl_loi_list_lock);
+       spin_lock(&cli->cl_loi_list_lock);
        rc = list_empty(&ocw->ocw_entry);
-       client_obd_list_unlock(&cli->cl_loi_list_lock);
+       spin_unlock(&cli->cl_loi_list_lock);
        return rc;
 }
 
@@ -1521,22 +1573,22 @@ static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
        lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(AT_OFF ? obd_timeout : at_max),
                               NULL, LWI_ON_SIGNAL_NOOP, NULL);
 
-       OSC_DUMP_GRANT(D_CACHE, cli, "need:%d", bytes);
+       OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
 
-       client_obd_list_lock(&cli->cl_loi_list_lock);
+       spin_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_pages == 0 ||
            cli->cl_ar.ar_force_sync || loi->loi_ar.ar_force_sync) {
-               OSC_DUMP_GRANT(D_CACHE, cli, "forced sync i/o");
+               OSC_DUMP_GRANT(D_CACHE, cli, "forced sync i/o\n");
                GOTO(out, rc = -EDQUOT);
        }
 
        /* Hopefully normal case - cache space and write credits available */
        if (osc_enter_cache_try(cli, oap, bytes, 0)) {
-               OSC_DUMP_GRANT(D_CACHE, cli, "granted from cache");
+               OSC_DUMP_GRANT(D_CACHE, cli, "granted from cache\n");
                GOTO(out, rc = 0);
        }
 
@@ -1552,16 +1604,16 @@ static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
        while (cli->cl_dirty_pages > 0 || cli->cl_w_in_flight > 0) {
                list_add_tail(&ocw.ocw_entry, &cli->cl_cache_waiters);
                ocw.ocw_rc = 0;
-               client_obd_list_unlock(&cli->cl_loi_list_lock);
+               spin_unlock(&cli->cl_loi_list_lock);
 
                osc_io_unplug_async(env, cli, NULL);
 
                CDEBUG(D_CACHE, "%s: sleeping for cache space @ %p for %p\n",
-                      cli->cl_import->imp_obd->obd_name, &ocw, oap);
+                      cli_name(cli), &ocw, oap);
 
                rc = l_wait_event(ocw.ocw_waitq, ocw_granted(cli, &ocw), &lwi);
 
-               client_obd_list_lock(&cli->cl_loi_list_lock);
+               spin_lock(&cli->cl_loi_list_lock);
 
                if (rc < 0) {
                        /* l_wait_event is interrupted by signal or timed out */
@@ -1581,34 +1633,33 @@ static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
 
        switch (rc) {
        case 0:
-               OSC_DUMP_GRANT(D_CACHE, cli, "finally got grant space");
+               OSC_DUMP_GRANT(D_CACHE, cli, "finally got grant space\n");
                break;
        case -ETIMEDOUT:
-               OSC_DUMP_GRANT(D_CACHE, cli, "timeout, fall back to sync i/o");
+               OSC_DUMP_GRANT(D_CACHE, cli,
+                              "timeout, fall back to sync i/o\n");
                osc_extent_tree_dump(D_CACHE, osc);
                /* fall back to synchronous I/O */
                rc = -EDQUOT;
                break;
        case -EINTR:
                /* Ensures restartability - LU-3581 */
-               OSC_DUMP_GRANT(D_CACHE, cli, "interrupted");
+               OSC_DUMP_GRANT(D_CACHE, cli, "interrupted\n");
                rc = -ERESTARTSYS;
                break;
        case -EDQUOT:
-               OSC_DUMP_GRANT(D_CACHE, cli, "no grant space, fall back to sync"
-                              " i/o");
+               OSC_DUMP_GRANT(D_CACHE, cli,
+                              "no grant space, fall back to sync i/o\n");
                break;
        default:
                CDEBUG(D_CACHE, "%s: event for cache space @ %p never arrived "
                       "due to %d, fall back to sync i/o\n",
-                      cli->cl_import->imp_obd->obd_name, &ocw, rc);
-               /* fall back to synchronous I/O */
-               rc = -EDQUOT;
+                      cli_name(cli), &ocw, rc);
                break;
        }
        EXIT;
 out:
-       client_obd_list_unlock(&cli->cl_loi_list_lock);
+       spin_unlock(&cli->cl_loi_list_lock);
        RETURN(rc);
 }
 
@@ -1626,10 +1677,12 @@ void osc_wake_cache_waiters(struct client_obd *cli)
                ocw->ocw_rc = -EDQUOT;
                /* we can't dirty more */
                if ((cli->cl_dirty_pages  >= cli->cl_dirty_max_pages) ||
-                   (1 + atomic_read(&obd_dirty_pages) > obd_max_dirty_pages)) {
+                   (1 + atomic_long_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_pages,
-                              cli->cl_dirty_max_pages, obd_max_dirty_pages);
+                              "osc max %ld, sys max %ld\n",
+                              cli->cl_dirty_pages, cli->cl_dirty_max_pages,
+                              obd_max_dirty_pages);
                        goto wakeup;
                }
 
@@ -1764,9 +1817,9 @@ static int osc_list_maint(struct client_obd *cli, struct osc_object *osc)
 {
        int is_ready;
 
-       client_obd_list_lock(&cli->cl_loi_list_lock);
+       spin_lock(&cli->cl_loi_list_lock);
        is_ready = __osc_list_maint(cli, osc);
-       client_obd_list_unlock(&cli->cl_loi_list_lock);
+       spin_unlock(&cli->cl_loi_list_lock);
 
        return is_ready;
 }
@@ -1816,10 +1869,10 @@ static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
        oap->oap_interrupted = 0;
 
        if (oap->oap_cmd & OBD_BRW_WRITE && xid > 0) {
-               client_obd_list_lock(&cli->cl_loi_list_lock);
+               spin_lock(&cli->cl_loi_list_lock);
                osc_process_ar(&cli->cl_ar, xid, rc);
                osc_process_ar(&loi->loi_ar, xid, rc);
-               client_obd_list_unlock(&cli->cl_loi_list_lock);
+               spin_unlock(&cli->cl_loi_list_lock);
        }
 
        rc = osc_completion(env, oap, oap->oap_cmd, rc);
@@ -1838,7 +1891,7 @@ static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
 static int try_to_add_extent_for_io(struct client_obd *cli,
                                    struct osc_extent *ext,
                                    struct list_head *rpclist,
-                                   int *pc, unsigned int *max_pages)
+                                   unsigned int *pc, unsigned int *max_pages)
 {
        struct osc_extent *tmp;
        struct osc_async_page *oap = list_first_entry(&ext->oe_pages,
@@ -1871,7 +1924,8 @@ static int try_to_add_extent_for_io(struct client_obd *cli,
                }
 
                if (tmp->oe_srvlock != ext->oe_srvlock ||
-                   !tmp->oe_grants != !ext->oe_grants)
+                   !tmp->oe_grants != !ext->oe_grants ||
+                   tmp->oe_no_merge || ext->oe_no_merge)
                        RETURN(0);
 
                /* remove break for strict check */
@@ -1897,11 +1951,12 @@ static int try_to_add_extent_for_io(struct client_obd *cli,
  * 5. Traverse the extent tree from the 1st extent;
  * 6. Above steps exit if there is no space in this RPC.
  */
-static int get_write_extents(struct osc_object *obj, struct list_head *rpclist)
+static unsigned int get_write_extents(struct osc_object *obj,
+                                     struct list_head *rpclist)
 {
        struct client_obd *cli = osc_cli(obj);
        struct osc_extent *ext;
-       int page_count = 0;
+       unsigned int page_count = 0;
        unsigned int max_pages = cli->cl_max_pages_per_rpc;
 
        LASSERT(osc_object_is_locked(obj));
@@ -1961,14 +2016,14 @@ static int get_write_extents(struct osc_object *obj, struct list_head *rpclist)
 
 static int
 osc_send_write_rpc(const struct lu_env *env, struct client_obd *cli,
-                  struct osc_object *osc, pdl_policy_t pol)
+                  struct osc_object *osc)
 __must_hold(osc)
 {
        struct list_head   rpclist = LIST_HEAD_INIT(rpclist);
        struct osc_extent *ext;
        struct osc_extent *tmp;
        struct osc_extent *first = NULL;
-       obd_count page_count = 0;
+       unsigned int page_count = 0;
        int srvlock = 0;
        int rc = 0;
        ENTRY;
@@ -2015,7 +2070,7 @@ __must_hold(osc)
 
        if (!list_empty(&rpclist)) {
                LASSERT(page_count > 0);
-               rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_WRITE, pol);
+               rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_WRITE);
                LASSERT(list_empty(&rpclist));
        }
 
@@ -2035,13 +2090,13 @@ __must_hold(osc)
  */
 static int
 osc_send_read_rpc(const struct lu_env *env, struct client_obd *cli,
-                 struct osc_object *osc, pdl_policy_t pol)
+                 struct osc_object *osc)
 __must_hold(osc)
 {
        struct osc_extent *ext;
        struct osc_extent *next;
        struct list_head rpclist = LIST_HEAD_INIT(rpclist);
-       int page_count = 0;
+       unsigned int page_count = 0;
        unsigned int max_pages = cli->cl_max_pages_per_rpc;
        int rc = 0;
        ENTRY;
@@ -2064,7 +2119,7 @@ __must_hold(osc)
                osc_object_unlock(osc);
 
                LASSERT(page_count > 0);
-               rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_READ, pol);
+               rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_READ);
                LASSERT(list_empty(&rpclist));
 
                osc_object_lock(osc);
@@ -2114,8 +2169,7 @@ static struct osc_object *osc_next_obj(struct client_obd *cli)
 }
 
 /* called with the loi list lock held */
-static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli,
-                          pdl_policy_t pol)
+static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli)
 __must_hold(&cli->cl_loi_list_lock)
 {
        struct osc_object *osc;
@@ -2134,7 +2188,7 @@ __must_hold(&cli->cl_loi_list_lock)
                }
 
                cl_object_get(obj);
-               client_obd_list_unlock(&cli->cl_loi_list_lock);
+               spin_unlock(&cli->cl_loi_list_lock);
                lu_object_ref_add_at(&obj->co_lu, &link, "check", current);
 
                /* attempt some read/write balancing by alternating between
@@ -2145,7 +2199,7 @@ __must_hold(&cli->cl_loi_list_lock)
                 * do io on writes while there are cache waiters */
                osc_object_lock(osc);
                if (osc_makes_rpc(cli, osc, OBD_BRW_WRITE)) {
-                       rc = osc_send_write_rpc(env, cli, osc, pol);
+                       rc = osc_send_write_rpc(env, cli, osc);
                        if (rc < 0) {
                                CERROR("Write request failed with %d\n", rc);
 
@@ -2169,7 +2223,7 @@ __must_hold(&cli->cl_loi_list_lock)
                        }
                }
                if (osc_makes_rpc(cli, osc, OBD_BRW_READ)) {
-                       rc = osc_send_read_rpc(env, cli, osc, pol);
+                       rc = osc_send_read_rpc(env, cli, osc);
                        if (rc < 0)
                                CERROR("Read request failed with %d\n", rc);
                }
@@ -2179,12 +2233,12 @@ __must_hold(&cli->cl_loi_list_lock)
                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);
+               spin_lock(&cli->cl_loi_list_lock);
        }
 }
 
 static int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
-                         struct osc_object *osc, pdl_policy_t pol, int async)
+                         struct osc_object *osc, int async)
 {
        int rc = 0;
 
@@ -2192,13 +2246,9 @@ static int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
                return 0;
 
        if (!async) {
-               /* disable osc_lru_shrink() temporarily to avoid
-                * potential stack overrun problem. LU-2859 */
-               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);
-               atomic_dec(&cli->cl_lru_shrinkers);
+               spin_lock(&cli->cl_loi_list_lock);
+               osc_check_rpcs(env, cli);
+               spin_unlock(&cli->cl_loi_list_lock);
        } else {
                CDEBUG(D_CACHE, "Queue writeback work for client %p.\n", cli);
                LASSERT(cli->cl_writeback_work != NULL);
@@ -2210,14 +2260,13 @@ static int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
 static int osc_io_unplug_async(const struct lu_env *env,
                                struct client_obd *cli, struct osc_object *osc)
 {
-       /* XXX: policy is no use actually. */
-       return osc_io_unplug0(env, cli, osc, PDL_POLICY_ROUND, 1);
+       return osc_io_unplug0(env, cli, osc, 1);
 }
 
 void osc_io_unplug(const struct lu_env *env, struct client_obd *cli,
-                  struct osc_object *osc, pdl_policy_t pol)
+                  struct osc_object *osc)
 {
-       (void)osc_io_unplug0(env, cli, osc, pol, 0);
+       (void)osc_io_unplug0(env, cli, osc, 0);
 }
 
 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
@@ -2236,9 +2285,9 @@ int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
 
        oap->oap_page = page;
        oap->oap_obj_off = offset;
-       LASSERT(!(offset & ~CFS_PAGE_MASK));
+       LASSERT(!(offset & ~PAGE_MASK));
 
-       if (!client_is_remote(exp) && cfs_capable(CFS_CAP_SYS_RESOURCE))
+       if (cfs_capable(CFS_CAP_SYS_RESOURCE))
                oap->oap_brw_flags = OBD_BRW_NOQUOTA;
 
        INIT_LIST_HEAD(&oap->oap_pending_item);
@@ -2259,8 +2308,9 @@ int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
        struct client_obd     *cli = oap->oap_cli;
        struct osc_object     *osc = oap->oap_obj;
        pgoff_t index;
-       int    grants = 0;
-       int    brw_flags = OBD_BRW_ASYNC;
+       unsigned int tmp;
+       unsigned int grants = 0;
+       u32    brw_flags = OBD_BRW_ASYNC;
        int    cmd = OBD_BRW_WRITE;
        int    need_release = 0;
        int    rc = 0;
@@ -2278,8 +2328,7 @@ int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
 
        /* Set the OBD_BRW_SRVLOCK before the page is queued. */
        brw_flags |= ops->ops_srvlock ? OBD_BRW_SRVLOCK : 0;
-       if (!client_is_remote(osc_export(osc)) &&
-           cfs_capable(CFS_CAP_SYS_RESOURCE)) {
+       if (cfs_capable(CFS_CAP_SYS_RESOURCE)) {
                brw_flags |= OBD_BRW_NOQUOTA;
                cmd |= OBD_BRW_NOQUOTA;
        }
@@ -2288,7 +2337,7 @@ int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
        if (!(cmd & OBD_BRW_NOQUOTA)) {
                struct cl_object *obj;
                struct cl_attr   *attr;
-               unsigned int qid[MAXQUOTAS];
+               unsigned int qid[LL_MAXQUOTAS];
 
                obj = cl_object_top(&osc->oo_cl);
                attr = &osc_env_info(env)->oti_attr;
@@ -2328,19 +2377,19 @@ int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
        if (ext != NULL && ext->oe_start <= index && ext->oe_max_end >= index) {
                /* one chunk plus extent overhead must be enough to write this
                 * page */
-               grants = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
+               grants = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
                if (ext->oe_end >= index)
                        grants = 0;
 
                /* it doesn't need any grant to dirty this page */
-               client_obd_list_lock(&cli->cl_loi_list_lock);
+               spin_lock(&cli->cl_loi_list_lock);
                rc = osc_enter_cache_try(cli, oap, grants, 0);
-               client_obd_list_unlock(&cli->cl_loi_list_lock);
+               spin_unlock(&cli->cl_loi_list_lock);
                if (rc == 0) { /* try failed */
                        grants = 0;
                        need_release = 1;
                } else if (ext->oe_end < index) {
-                       int tmp = grants;
+                       tmp = grants;
                        /* try to expand this extent */
                        rc = osc_extent_expand(ext, index, &tmp);
                        if (rc < 0) {
@@ -2365,7 +2414,7 @@ int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
        }
 
        if (ext == NULL) {
-               int tmp = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
+               tmp = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
 
                /* try to find new extent to cover this page */
                LASSERT(oio->oi_active == NULL);
@@ -2419,7 +2468,6 @@ int osc_teardown_async_page(const struct lu_env *env,
                            struct osc_object *obj, struct osc_page *ops)
 {
        struct osc_async_page *oap = &ops->ops_oap;
-       struct osc_extent     *ext = NULL;
        int rc = 0;
        ENTRY;
 
@@ -2428,12 +2476,15 @@ int osc_teardown_async_page(const struct lu_env *env,
        CDEBUG(D_INFO, "teardown oap %p page %p at index %lu.\n",
               oap, ops, osc_index(oap2osc(oap)));
 
-       osc_object_lock(obj);
        if (!list_empty(&oap->oap_rpc_item)) {
                CDEBUG(D_CACHE, "oap %p is not in cache.\n", oap);
                rc = -EBUSY;
        } else if (!list_empty(&oap->oap_pending_item)) {
+               struct osc_extent *ext = NULL;
+
+               osc_object_lock(obj);
                ext = osc_extent_lookup(obj, osc_index(oap2osc(oap)));
+               osc_object_unlock(obj);
                /* only truncated pages are allowed to be taken out.
                 * See osc_extent_truncate() and osc_cache_truncate_start()
                 * for details. */
@@ -2442,10 +2493,9 @@ int osc_teardown_async_page(const struct lu_env *env,
                                        osc_index(oap2osc(oap)));
                        rc = -EBUSY;
                }
+               if (ext != NULL)
+                       osc_extent_put(env, ext);
        }
-       osc_object_unlock(obj);
-       if (ext != NULL)
-               osc_extent_put(env, ext);
        RETURN(rc);
 }
 
@@ -2604,23 +2654,31 @@ int osc_queue_sync_pages(const struct lu_env *env, struct osc_object *obj,
        struct osc_async_page *oap;
        int     page_count = 0;
        int     mppr       = cli->cl_max_pages_per_rpc;
+       bool    can_merge   = true;
        pgoff_t start      = CL_PAGE_EOF;
        pgoff_t end        = 0;
        ENTRY;
 
        list_for_each_entry(oap, list, oap_pending_item) {
-               pgoff_t index = osc_index(oap2osc(oap));
+               struct osc_page *opg = oap2osc_page(oap);
+               pgoff_t index = osc_index(opg);
+
                if (index > end)
                        end = index;
                if (index < start)
                        start = index;
                ++page_count;
                mppr <<= (page_count > mppr);
+
+               if (unlikely(opg->ops_from > 0 || opg->ops_to < PAGE_SIZE))
+                       can_merge = false;
        }
 
        ext = osc_extent_alloc(obj);
        if (ext == NULL) {
-               list_for_each_entry(oap, list, oap_pending_item) {
+               struct osc_async_page *tmp;
+
+               list_for_each_entry_safe(oap, tmp, list, oap_pending_item) {
                        list_del_init(&oap->oap_pending_item);
                        osc_ap_completion(env, cli, oap, 0, -ENOMEM);
                }
@@ -2628,6 +2686,8 @@ int osc_queue_sync_pages(const struct lu_env *env, struct osc_object *obj,
        }
 
        ext->oe_rw = !!(cmd & OBD_BRW_READ);
+       ext->oe_sync = 1;
+       ext->oe_no_merge = !can_merge;
        ext->oe_urgent = 1;
        ext->oe_start = start;
        ext->oe_end = ext->oe_max_end = end;
@@ -2656,8 +2716,8 @@ int osc_queue_sync_pages(const struct lu_env *env, struct osc_object *obj,
 /**
  * Called by osc_io_setattr_start() to freeze and destroy covering extents.
  */
-int osc_cache_truncate_start(const struct lu_env *env, struct osc_io *oio,
-                            struct osc_object *obj, __u64 size)
+int osc_cache_truncate_start(const struct lu_env *env, struct osc_object *obj,
+                            __u64 size, struct osc_extent **extp)
 {
        struct client_obd *cli = osc_cli(obj);
        struct osc_extent *ext;
@@ -2687,7 +2747,6 @@ again:
                         * a page already having been flushed by write_page().
                         * We have to wait for this extent because we can't
                         * truncate that page. */
-                       LASSERT(!ext->oe_hp);
                        OSC_EXTENT_DUMP(D_CACHE, ext,
                                        "waiting for busy extent\n");
                        waiting = osc_extent_get(ext);
@@ -2751,9 +2810,11 @@ again:
 
                        /* we need to hold this extent in OES_TRUNC state so
                         * that no writeback will happen. This is to avoid
-                        * BUG 17397. */
-                       LASSERT(oio->oi_trunc == NULL);
-                       oio->oi_trunc = osc_extent_get(ext);
+                        * BUG 17397.
+                        * Only partial truncate can reach here, if @size is
+                        * not zero, the caller should provide a valid @extp. */
+                       LASSERT(*extp == NULL);
+                       *extp = osc_extent_get(ext);
                        OSC_EXTENT_DUMP(D_CACHE, ext,
                                        "trunc at "LPU64"\n", size);
                }
@@ -2778,13 +2839,10 @@ again:
 /**
  * Called after osc_io_setattr_end to add oio->oi_trunc back to cache.
  */
-void osc_cache_truncate_end(const struct lu_env *env, struct osc_io *oio,
-                           struct osc_object *obj)
+void osc_cache_truncate_end(const struct lu_env *env, struct osc_extent *ext)
 {
-       struct osc_extent *ext = oio->oi_trunc;
-
-       oio->oi_trunc = NULL;
        if (ext != NULL) {
+               struct osc_object *obj = ext->oe_obj;
                bool unplug = false;
 
                EASSERT(ext->oe_nr_pages > 0, ext);
@@ -2967,7 +3025,7 @@ int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
        }
 
        if (unplug)
-               osc_io_unplug(env, osc_cli(obj), obj, PDL_POLICY_ROUND);
+               osc_io_unplug(env, osc_cli(obj), obj);
 
        if (hp || discard) {
                int rc;
@@ -3079,26 +3137,27 @@ static int check_and_discard_cb(const struct lu_env *env, struct cl_io *io,
                                struct osc_page *ops, void *cbdata)
 {
        struct osc_thread_info *info = osc_env_info(env);
-       struct cl_lock *lock = cbdata;
+       struct osc_object *osc = cbdata;
        pgoff_t index;
 
        index = osc_index(ops);
        if (index >= info->oti_fn_index) {
-               struct cl_lock *tmp;
+               struct ldlm_lock *tmp;
                struct cl_page *page = ops->ops_cl.cpl_page;
 
                /* refresh non-overlapped index */
-               tmp = cl_lock_at_pgoff(env, lock->cll_descr.cld_obj, index,
-                                      lock, 1, 0);
+               tmp = osc_dlmlock_at_pgoff(env, osc, index,
+                                          OSC_DAP_FL_TEST_LOCK);
                if (tmp != NULL) {
+                       __u64 end = tmp->l_policy_data.l_extent.end;
                        /* Cache the first-non-overlapped index so as to skip
-                        * all pages within [index, oti_fn_index). This
-                        * is safe because if tmp lock is canceled, it will
-                        * discard these pages. */
-                       info->oti_fn_index = tmp->cll_descr.cld_end + 1;
-                       if (tmp->cll_descr.cld_end == CL_PAGE_EOF)
+                        * all pages within [index, oti_fn_index). This is safe
+                        * because if tmp lock is canceled, it will discard
+                        * these pages. */
+                       info->oti_fn_index = cl_index(osc2cl(osc), end + 1);
+                       if (end == OBD_OBJECT_EOF)
                                info->oti_fn_index = CL_PAGE_EOF;
-                       cl_lock_put(env, tmp);
+                       LDLM_LOCK_PUT(tmp);
                } else if (cl_page_own(env, io, page) == 0) {
                        /* discard the page */
                        cl_page_discard(env, io, page);
@@ -3116,16 +3175,15 @@ static int discard_cb(const struct lu_env *env, struct cl_io *io,
                      struct osc_page *ops, void *cbdata)
 {
        struct osc_thread_info *info = osc_env_info(env);
-       struct cl_lock *lock = cbdata;
        struct cl_page *page = ops->ops_cl.cpl_page;
 
-       LASSERT(lock->cll_descr.cld_mode >= CLM_WRITE);
-
        /* page is top page. */
        info->oti_next_index = osc_index(ops) + 1;
        if (cl_page_own(env, io, page) == 0) {
-               KLASSERT(ergo(page->cp_type == CPT_CACHEABLE,
-                             !PageDirty(cl_page_vmpage(page))));
+               if (!ergo(page->cp_type == CPT_CACHEABLE,
+                         !PageDirty(cl_page_vmpage(page))))
+                       CL_PAGE_DEBUG(D_ERROR, env, page,
+                                       "discard dirty page?\n");
 
                /* discard the page */
                cl_page_discard(env, io, page);
@@ -3145,32 +3203,29 @@ static int discard_cb(const struct lu_env *env, struct cl_io *io,
  * If error happens on any step, the process continues anyway (the reasoning
  * behind this being that lock cancellation cannot be delayed indefinitely).
  */
-int osc_lock_discard_pages(const struct lu_env *env, struct osc_lock *ols)
+int osc_lock_discard_pages(const struct lu_env *env, struct osc_object *osc,
+                          pgoff_t start, pgoff_t end, enum cl_lock_mode mode)
 {
        struct osc_thread_info *info = osc_env_info(env);
        struct cl_io *io = &info->oti_io;
-       struct cl_object *osc = ols->ols_cl.cls_obj;
-       struct cl_lock *lock = ols->ols_cl.cls_lock;
-       struct cl_lock_descr *descr = &lock->cll_descr;
        osc_page_gang_cbt cb;
        int res;
        int result;
 
        ENTRY;
 
-       io->ci_obj = cl_object_top(osc);
+       io->ci_obj = cl_object_top(osc2cl(osc));
        io->ci_ignore_layout = 1;
        result = cl_io_init(env, io, CIT_MISC, io->ci_obj);
        if (result != 0)
                GOTO(out, result);
 
-       cb = descr->cld_mode == CLM_READ ? check_and_discard_cb : discard_cb;
-       info->oti_fn_index = info->oti_next_index = descr->cld_start;
+       cb = mode == CLM_READ ? check_and_discard_cb : discard_cb;
+       info->oti_fn_index = info->oti_next_index = start;
        do {
-               res = osc_page_gang_lookup(env, io, cl2osc(osc),
-                                          info->oti_next_index, descr->cld_end,
-                                          cb, (void *)lock);
-               if (info->oti_next_index > descr->cld_end)
+               res = osc_page_gang_lookup(env, io, osc,
+                                          info->oti_next_index, end, cb, osc);
+               if (info->oti_next_index > end)
                        break;
 
                if (res == CLP_GANG_RESCHED)