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LU-14711 osc: Do not attempt sending empty pages
[fs/lustre-release.git] / lustre / osc / osc_request.c
index a41abd8..4ca9be0 100644 (file)
@@ -27,7 +27,6 @@
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
- * Lustre is a trademark of Sun Microsystems, Inc.
  */
 
 #define DEBUG_SUBSYSTEM S_OSC
@@ -36,7 +35,6 @@
 #include <libcfs/libcfs.h>
 #include <linux/falloc.h>
 #include <lprocfs_status.h>
-#include <lustre_debug.h>
 #include <lustre_dlm.h>
 #include <lustre_fid.h>
 #include <lustre_ha.h>
@@ -50,6 +48,7 @@
 #include <linux/falloc.h>
 
 #include "osc_internal.h"
+#include <lnet/lnet_rdma.h>
 
 atomic_t osc_pool_req_count;
 unsigned int osc_reqpool_maxreqcount;
@@ -450,14 +449,7 @@ int osc_fallocate_base(struct obd_export *exp, struct obdo *oa,
        int rc;
        ENTRY;
 
-       /*
-        * Only mode == 0 (which is standard prealloc) is supported now.
-        * Punch is not supported yet.
-        */
-       if (mode & ~FALLOC_FL_KEEP_SIZE)
-               RETURN(-EOPNOTSUPP);
        oa->o_falloc_mode = mode;
-
        req = ptlrpc_request_alloc(class_exp2cliimp(exp),
                                   &RQF_OST_FALLOCATE);
        if (req == NULL)
@@ -476,7 +468,7 @@ int osc_fallocate_base(struct obd_export *exp, struct obdo *oa,
 
        ptlrpc_request_set_replen(req);
 
-       req->rq_interpret_reply = (ptlrpc_interpterer_t)osc_setattr_interpret;
+       req->rq_interpret_reply = osc_setattr_interpret;
        BUILD_BUG_ON(sizeof(*sa) > sizeof(req->rq_async_args));
        sa = ptlrpc_req_async_args(sa, req);
        sa->sa_oa = oa;
@@ -487,6 +479,7 @@ int osc_fallocate_base(struct obd_export *exp, struct obdo *oa,
 
        RETURN(0);
 }
+EXPORT_SYMBOL(osc_fallocate_base);
 
 static int osc_sync_interpret(const struct lu_env *env,
                              struct ptlrpc_request *req, void *args, int rc)
@@ -699,7 +692,7 @@ static void osc_announce_cached(struct client_obd *cli, struct obdo *oa,
 
        oa->o_valid |= bits;
        spin_lock(&cli->cl_loi_list_lock);
-       if (OCD_HAS_FLAG(&cli->cl_import->imp_connect_data, GRANT_PARAM))
+       if (cli->cl_ocd_grant_param)
                oa->o_dirty = cli->cl_dirty_grant;
        else
                oa->o_dirty = cli->cl_dirty_pages << PAGE_SHIFT;
@@ -730,13 +723,12 @@ static void osc_announce_cached(struct client_obd *cli, struct obdo *oa,
                nrpages *= cli->cl_max_rpcs_in_flight + 1;
                nrpages = max(nrpages, cli->cl_dirty_max_pages);
                undirty = nrpages << PAGE_SHIFT;
-               if (OCD_HAS_FLAG(&cli->cl_import->imp_connect_data,
-                                GRANT_PARAM)) {
+               if (cli->cl_ocd_grant_param) {
                        int nrextents;
 
                        /* take extent tax into account when asking for more
                         * grant space */
-                       nrextents = (nrpages + cli->cl_max_extent_pages - 1)  /
+                       nrextents = (nrpages + cli->cl_max_extent_pages - 1) /
                                     cli->cl_max_extent_pages;
                        undirty += nrextents * cli->cl_grant_extent_tax;
                }
@@ -1062,10 +1054,10 @@ void osc_init_grant(struct client_obd *cli, struct obd_connect_data *ocd)
                                             ~chunk_mask) & chunk_mask;
                /* determine maximum extent size, in #pages */
                size = (u64)ocd->ocd_grant_max_blks << ocd->ocd_grant_blkbits;
-               cli->cl_max_extent_pages = size >> PAGE_SHIFT;
-               if (cli->cl_max_extent_pages == 0)
-                       cli->cl_max_extent_pages = 1;
+               cli->cl_max_extent_pages = (size >> PAGE_SHIFT) ?: 1;
+               cli->cl_ocd_grant_param = 1;
        } else {
+               cli->cl_ocd_grant_param = 0;
                cli->cl_grant_extent_tax = 0;
                cli->cl_chunkbits = PAGE_SHIFT;
                cli->cl_max_extent_pages = DT_MAX_BRW_PAGES;
@@ -1186,7 +1178,7 @@ static int osc_checksum_bulk_t10pi(const char *obd_name, int nob,
                                   size_t pg_count, struct brw_page **pga,
                                   int opc, obd_dif_csum_fn *fn,
                                   int sector_size,
-                                  u32 *check_sum)
+                                  u32 *check_sum, bool resend)
 {
        struct ahash_request *req;
        /* Used Adler as the default checksum type on top of DIF tags */
@@ -1219,6 +1211,10 @@ static int osc_checksum_bulk_t10pi(const char *obd_name, int nob,
        buffer = kmap(__page);
        guard_start = (__u16 *)buffer;
        guard_number = PAGE_SIZE / sizeof(*guard_start);
+       CDEBUG(D_PAGE | (resend ? D_HA : 0),
+              "GRD tags per page=%u, resend=%u, bytes=%u, pages=%zu\n",
+              guard_number, resend, nob, pg_count);
+
        while (nob > 0 && pg_count > 0) {
                unsigned int count = pga[i]->count > nob ? nob : pga[i]->count;
 
@@ -1244,6 +1240,12 @@ static int osc_checksum_bulk_t10pi(const char *obd_name, int nob,
                                                  guard_number - used_number,
                                                  &used, sector_size,
                                                  fn);
+               if (unlikely(resend))
+                       CDEBUG(D_PAGE | D_HA,
+                              "pga[%u]: used %u off %llu+%u gen checksum: %*phN\n",
+                              i, used, pga[i]->off & ~PAGE_MASK, count,
+                              (int)(used * sizeof(*guard_start)),
+                              guard_start + used_number);
                if (rc)
                        break;
 
@@ -1282,7 +1284,7 @@ out:
 #else /* !CONFIG_CRC_T10DIF */
 #define obd_dif_ip_fn NULL
 #define obd_dif_crc_fn NULL
-#define osc_checksum_bulk_t10pi(name, nob, pgc, pga, opc, fn, ssize, csum \
+#define osc_checksum_bulk_t10pi(name, nob, pgc, pga, opc, fn, ssize, csum, re) \
        -EOPNOTSUPP
 #endif /* CONFIG_CRC_T10DIF */
 
@@ -1344,7 +1346,7 @@ static int osc_checksum_bulk_rw(const char *obd_name,
                                enum cksum_types cksum_type,
                                int nob, size_t pg_count,
                                struct brw_page **pga, int opc,
-                               u32 *check_sum)
+                               u32 *check_sum, bool resend)
 {
        obd_dif_csum_fn *fn = NULL;
        int sector_size = 0;
@@ -1355,7 +1357,8 @@ static int osc_checksum_bulk_rw(const char *obd_name,
 
        if (fn)
                rc = osc_checksum_bulk_t10pi(obd_name, nob, pg_count, pga,
-                                            opc, fn, sector_size, check_sum);
+                                            opc, fn, sector_size, check_sum,
+                                            resend);
        else
                rc = osc_checksum_bulk(nob, pg_count, pga, opc, cksum_type,
                                       check_sum);
@@ -1398,10 +1401,26 @@ osc_brw_prep_request(int cmd, struct client_obd *cli, struct obdo *oa,
        struct brw_page *pg_prev;
        void *short_io_buf;
        const char *obd_name = cli->cl_import->imp_obd->obd_name;
-       struct inode *inode;
+       struct inode *inode = NULL;
+       bool directio = false;
+       bool enable_checksum = true;
 
        ENTRY;
-       inode = page2inode(pga[0]->pg);
+       if (pga[0]->pg) {
+               inode = page2inode(pga[0]->pg);
+               if (inode == NULL) {
+                       /* Try to get reference to inode from cl_page if we are
+                        * dealing with direct IO, as handled pages are not
+                        * actual page cache pages.
+                        */
+                       struct osc_async_page *oap = brw_page2oap(pga[0]);
+                       struct cl_page *clpage = oap2cl_page(oap);
+
+                       inode = clpage->cp_inode;
+                       if (inode)
+                               directio = true;
+               }
+       }
        if (OBD_FAIL_CHECK(OBD_FAIL_OSC_BRW_PREP_REQ))
                RETURN(-ENOMEM); /* Recoverable */
        if (OBD_FAIL_CHECK(OBD_FAIL_OSC_BRW_PREP_REQ2))
@@ -1426,6 +1445,8 @@ osc_brw_prep_request(int cmd, struct client_obd *cli, struct obdo *oa,
                        bool retried = false;
                        bool lockedbymyself;
                        u32 nunits = (pg->off & ~PAGE_MASK) + pg->count;
+                       struct address_space *map_orig = NULL;
+                       pgoff_t index_orig;
 
 retry_encrypt:
                        if (nunits & ~LUSTRE_ENCRYPTION_MASK)
@@ -1441,10 +1462,20 @@ retry_encrypt:
                         * which means only once the page is fully processed.
                         */
                        lockedbymyself = trylock_page(pg->pg);
+                       if (directio) {
+                               map_orig = pg->pg->mapping;
+                               pg->pg->mapping = inode->i_mapping;
+                               index_orig = pg->pg->index;
+                               pg->pg->index = pg->off >> PAGE_SHIFT;
+                       }
                        data_page =
                                llcrypt_encrypt_pagecache_blocks(pg->pg,
                                                                 nunits, 0,
                                                                 GFP_NOFS);
+                       if (directio) {
+                               pg->pg->mapping = map_orig;
+                               pg->pg->index = index_orig;
+                       }
                        if (lockedbymyself)
                                unlock_page(pg->pg);
                        if (IS_ERR(data_page)) {
@@ -1516,11 +1547,22 @@ retry_encrypt:
                }
        }
 
+       if (lnet_is_rdma_only_page(pga[0]->pg)) {
+               enable_checksum = false;
+               short_io_size = 0;
+       }
+
        /* Check if read/write is small enough to be a short io. */
        if (short_io_size > cli->cl_max_short_io_bytes || niocount > 1 ||
            !imp_connect_shortio(cli->cl_import))
                short_io_size = 0;
 
+       /* If this is an empty RPC to old server, just ignore it */
+       if (!short_io_size && !pga[0]->pg) {
+               ptlrpc_request_free(req);
+               RETURN(-ENODATA);
+       }
+
        req_capsule_set_size(pill, &RMF_SHORT_IO, RCL_CLIENT,
                             opc == OST_READ ? 0 : short_io_size);
        if (opc == OST_READ)
@@ -1665,10 +1707,12 @@ no_bulk:
         if (osc_should_shrink_grant(cli))
                 osc_shrink_grant_local(cli, &body->oa);
 
+       if (!cli->cl_checksum || sptlrpc_flavor_has_bulk(&req->rq_flvr))
+               enable_checksum = false;
+
         /* size[REQ_REC_OFF] still sizeof (*body) */
         if (opc == OST_WRITE) {
-                if (cli->cl_checksum &&
-                    !sptlrpc_flavor_has_bulk(&req->rq_flvr)) {
+                if (enable_checksum) {
                         /* store cl_cksum_type in a local variable since
                          * it can be changed via lprocfs */
                        enum cksum_types cksum_type = cli->cl_cksum_type;
@@ -1683,17 +1727,18 @@ no_bulk:
                        rc = osc_checksum_bulk_rw(obd_name, cksum_type,
                                                  requested_nob, page_count,
                                                  pga, OST_WRITE,
-                                                 &body->oa.o_cksum);
+                                                 &body->oa.o_cksum, resend);
                        if (rc < 0) {
-                               CDEBUG(D_PAGE, "failed to checksum, rc = %d\n",
+                               CDEBUG(D_PAGE, "failed to checksum: rc = %d\n",
                                       rc);
                                GOTO(out, rc);
                        }
-                        CDEBUG(D_PAGE, "checksum at write origin: %x\n",
-                               body->oa.o_cksum);
+                       CDEBUG(D_PAGE | (resend ? D_HA : 0),
+                              "checksum at write origin: %x (%x)\n",
+                              body->oa.o_cksum, cksum_type);
 
-                        /* save this in 'oa', too, for later checking */
-                        oa->o_valid |= OBD_MD_FLCKSUM | OBD_MD_FLFLAGS;
+                       /* save this in 'oa', too, for later checking */
+                       oa->o_valid |= OBD_MD_FLCKSUM | OBD_MD_FLFLAGS;
                        oa->o_flags |= obd_cksum_type_pack(obd_name,
                                                           cksum_type);
                 } else {
@@ -1706,8 +1751,7 @@ no_bulk:
                 req_capsule_set_size(pill, &RMF_RCS, RCL_SERVER,
                                      sizeof(__u32) * niocount);
         } else {
-                if (cli->cl_checksum &&
-                    !sptlrpc_flavor_has_bulk(&req->rq_flvr)) {
+                if (enable_checksum) {
                         if ((body->oa.o_valid & OBD_MD_FLFLAGS) == 0)
                                 body->oa.o_flags = 0;
                        body->oa.o_flags |= obd_cksum_type_pack(obd_name,
@@ -1759,15 +1803,15 @@ static void dump_all_bulk_pages(struct obdo *oa, __u32 page_count,
         * file/fid, not during the resends/retries. */
        snprintf(dbgcksum_file_name, sizeof(dbgcksum_file_name),
                 "%s-checksum_dump-osc-"DFID":[%llu-%llu]-%x-%x",
-                (strncmp(libcfs_debug_file_path_arr, "NONE", 4) != 0 ?
-                 libcfs_debug_file_path_arr :
-                 LIBCFS_DEBUG_FILE_PATH_DEFAULT),
+                (strncmp(libcfs_debug_file_path, "NONE", 4) != 0 ?
+                 libcfs_debug_file_path : LIBCFS_DEBUG_FILE_PATH_DEFAULT),
                 oa->o_valid & OBD_MD_FLFID ? oa->o_parent_seq : 0ULL,
                 oa->o_valid & OBD_MD_FLFID ? oa->o_parent_oid : 0,
                 oa->o_valid & OBD_MD_FLFID ? oa->o_parent_ver : 0,
                 pga[0]->off,
                 pga[page_count-1]->off + pga[page_count-1]->count - 1,
                 client_cksum, server_cksum);
+       CWARN("dumping checksum data to %s\n", dbgcksum_file_name);
        filp = filp_open(dbgcksum_file_name,
                         O_CREAT | O_EXCL | O_WRONLY | O_LARGEFILE, 0600);
        if (IS_ERR(filp)) {
@@ -1794,8 +1838,6 @@ static void dump_all_bulk_pages(struct obdo *oa, __u32 page_count,
                        }
                        len -= rc;
                        buf += rc;
-                       CDEBUG(D_INFO, "%s: wrote %d bytes\n",
-                              dbgcksum_file_name, rc);
                }
                kunmap(pga[i]->pg);
        }
@@ -1804,6 +1846,8 @@ static void dump_all_bulk_pages(struct obdo *oa, __u32 page_count,
        if (rc)
                CERROR("%s: sync returns %d\n", dbgcksum_file_name, rc);
        filp_close(filp, NULL);
+
+       libcfs_debug_dumplog();
 }
 
 static int
@@ -1856,7 +1900,7 @@ check_write_checksum(struct obdo *oa, const struct lnet_process_id *peer,
                rc = osc_checksum_bulk_t10pi(obd_name, aa->aa_requested_nob,
                                             aa->aa_page_count, aa->aa_ppga,
                                             OST_WRITE, fn, sector_size,
-                                            &new_cksum);
+                                            &new_cksum, true);
        else
                rc = osc_checksum_bulk(aa->aa_requested_nob, aa->aa_page_count,
                                       aa->aa_ppga, OST_WRITE, cksum_type,
@@ -1904,6 +1948,7 @@ static int osc_brw_fini_request(struct ptlrpc_request *req, int rc)
        struct ost_body *body;
        u32 client_cksum = 0;
        struct inode *inode;
+       unsigned int blockbits = 0, blocksize = 0;
 
        ENTRY;
 
@@ -2017,22 +2062,23 @@ static int osc_brw_fini_request(struct ptlrpc_request *req, int rc)
                }
        }
 
-        if (rc < aa->aa_requested_nob)
-                handle_short_read(rc, aa->aa_page_count, aa->aa_ppga);
+       if (rc < aa->aa_requested_nob)
+               handle_short_read(rc, aa->aa_page_count, aa->aa_ppga);
 
-        if (body->oa.o_valid & OBD_MD_FLCKSUM) {
-                static int cksum_counter;
-               u32        server_cksum = body->oa.o_cksum;
-               char      *via = "";
-               char      *router = "";
+       if (body->oa.o_valid & OBD_MD_FLCKSUM) {
+               static int cksum_counter;
+               u32 server_cksum = body->oa.o_cksum;
+               int nob = rc;
+               char *via = "";
+               char *router = "";
                enum cksum_types cksum_type;
                u32 o_flags = body->oa.o_valid & OBD_MD_FLFLAGS ?
                        body->oa.o_flags : 0;
 
                cksum_type = obd_cksum_type_unpack(o_flags);
-               rc = osc_checksum_bulk_rw(obd_name, cksum_type, rc,
+               rc = osc_checksum_bulk_rw(obd_name, cksum_type, nob,
                                          aa->aa_page_count, aa->aa_ppga,
-                                         OST_READ, &client_cksum);
+                                         OST_READ, &client_cksum, false);
                if (rc < 0)
                        GOTO(out, rc);
 
@@ -2044,8 +2090,12 @@ static int osc_brw_fini_request(struct ptlrpc_request *req, int rc)
 
                if (server_cksum != client_cksum) {
                        struct ost_body *clbody;
+                       __u32 client_cksum2;
                        u32 page_count = aa->aa_page_count;
 
+                       osc_checksum_bulk_rw(obd_name, cksum_type, nob,
+                                            page_count, aa->aa_ppga,
+                                            OST_READ, &client_cksum2, true);
                        clbody = req_capsule_client_get(&req->rq_pill,
                                                        &RMF_OST_BODY);
                        if (cli->cl_checksum_dump)
@@ -2055,7 +2105,7 @@ static int osc_brw_fini_request(struct ptlrpc_request *req, int rc)
 
                        LCONSOLE_ERROR_MSG(0x133, "%s: BAD READ CHECKSUM: from "
                                           "%s%s%s inode "DFID" object "DOSTID
-                                          " extent [%llu-%llu], client %x, "
+                                          " extent [%llu-%llu], client %x/%x, "
                                           "server %x, cksum_type %x\n",
                                           obd_name,
                                           libcfs_nid2str(peer->nid),
@@ -2070,8 +2120,8 @@ static int osc_brw_fini_request(struct ptlrpc_request *req, int rc)
                                           aa->aa_ppga[0]->off,
                                           aa->aa_ppga[page_count-1]->off +
                                           aa->aa_ppga[page_count-1]->count - 1,
-                                          client_cksum, server_cksum,
-                                          cksum_type);
+                                          client_cksum, client_cksum2,
+                                          server_cksum, cksum_type);
                        cksum_counter = 0;
                        aa->aa_oa->o_cksum = client_cksum;
                        rc = -EAGAIN;
@@ -2093,6 +2143,19 @@ static int osc_brw_fini_request(struct ptlrpc_request *req, int rc)
        }
 
        inode = page2inode(aa->aa_ppga[0]->pg);
+       if (inode == NULL) {
+               /* Try to get reference to inode from cl_page if we are
+                * dealing with direct IO, as handled pages are not
+                * actual page cache pages.
+                */
+               struct osc_async_page *oap = brw_page2oap(aa->aa_ppga[0]);
+
+               inode = oap2cl_page(oap)->cp_inode;
+               if (inode) {
+                       blockbits = inode->i_blkbits;
+                       blocksize = 1 << blockbits;
+               }
+       }
        if (inode && IS_ENCRYPTED(inode)) {
                int idx;
 
@@ -2117,18 +2180,36 @@ static int osc_brw_fini_request(struct ptlrpc_request *req, int rc)
                                        break;
                                }
 
-                               /* The page is already locked when we arrive here,
-                                * except when we deal with a twisted page for
-                                * specific Direct IO support, in which case
-                                * PageChecked flag is set on page.
-                                */
-                               if (PageChecked(pg->pg))
-                                       lock_page(pg->pg);
-                               rc = llcrypt_decrypt_pagecache_blocks(pg->pg,
-                                                   LUSTRE_ENCRYPTION_UNIT_SIZE,
-                                                                     offs);
-                               if (PageChecked(pg->pg))
-                                       unlock_page(pg->pg);
+                               if (blockbits) {
+                                       /* This is direct IO case. Directly call
+                                        * decrypt function that takes inode as
+                                        * input parameter. Page does not need
+                                        * to be locked.
+                                        */
+                                       u64 lblk_num =
+                                               ((u64)(pg->off >> PAGE_SHIFT) <<
+                                                    (PAGE_SHIFT - blockbits)) +
+                                                      (offs >> blockbits);
+                                       unsigned int i;
+
+                                       for (i = offs;
+                                            i < offs +
+                                                   LUSTRE_ENCRYPTION_UNIT_SIZE;
+                                            i += blocksize, lblk_num++) {
+                                               rc =
+                                                 llcrypt_decrypt_block_inplace(
+                                                         inode, pg->pg,
+                                                         blocksize, i,
+                                                         lblk_num);
+                                               if (rc)
+                                                       break;
+                                       }
+                               } else {
+                                       rc = llcrypt_decrypt_pagecache_blocks(
+                                               pg->pg,
+                                               LUSTRE_ENCRYPTION_UNIT_SIZE,
+                                               offs);
+                               }
                                if (rc)
                                        GOTO(out, rc);
 
@@ -2247,7 +2328,7 @@ static void sort_brw_pages(struct brw_page **array, int num)
 static void osc_release_ppga(struct brw_page **ppga, size_t count)
 {
        LASSERT(ppga != NULL);
-       OBD_FREE_PTR_ARRAY(ppga, count);
+       OBD_FREE_PTR_ARRAY_LARGE(ppga, count);
 }
 
 static int brw_interpret(const struct lu_env *env,
@@ -2279,7 +2360,7 @@ static int brw_interpret(const struct lu_env *env,
                               req->rq_import->imp_obd->obd_name,
                               POSTID(&aa->aa_oa->o_oi), rc);
                } else if (rc == -EINPROGRESS ||
-                   client_should_resend(aa->aa_resends, aa->aa_cli)) {
+                          client_should_resend(aa->aa_resends, aa->aa_cli)) {
                        rc = osc_brw_redo_request(req, aa, rc);
                } else {
                        CERROR("%s: too many resent retries for object: "
@@ -2354,7 +2435,7 @@ static int brw_interpret(const struct lu_env *env,
        list_for_each_entry_safe(ext, tmp, &aa->aa_exts, oe_link) {
                list_del_init(&ext->oe_link);
                osc_extent_finish(env, ext, 1,
-                                 rc && req->rq_no_delay ? -EWOULDBLOCK : rc);
+                                 rc && req->rq_no_delay ? -EAGAIN : rc);
        }
        LASSERT(list_empty(&aa->aa_exts));
        LASSERT(list_empty(&aa->aa_oaps));
@@ -2447,7 +2528,7 @@ int osc_build_rpc(const struct lu_env *env, struct client_obd *cli,
        if (mem_tight)
                mpflag = memalloc_noreclaim_save();
 
-       OBD_ALLOC_PTR_ARRAY(pga, page_count);
+       OBD_ALLOC_PTR_ARRAY_LARGE(pga, page_count);
        if (pga == NULL)
                GOTO(out, rc = -ENOMEM);
 
@@ -2484,7 +2565,7 @@ int osc_build_rpc(const struct lu_env *env, struct client_obd *cli,
        }
 
        /* first page in the list */
-       oap = list_entry(rpc_list.next, typeof(*oap), oap_rpc_item);
+       oap = list_first_entry(&rpc_list, typeof(*oap), oap_rpc_item);
 
        crattr = &osc_env_info(env)->oti_req_attr;
        memset(crattr, 0, sizeof(*crattr));
@@ -2580,10 +2661,11 @@ out:
                        osc_release_ppga(pga, page_count);
                }
                /* this should happen rarely and is pretty bad, it makes the
-                * pending list not follow the dirty order */
-               while (!list_empty(ext_list)) {
-                       ext = list_entry(ext_list->next, struct osc_extent,
-                                        oe_link);
+                * pending list not follow the dirty order
+                */
+               while ((ext = list_first_entry_or_null(ext_list,
+                                                      struct osc_extent,
+                                                      oe_link)) != NULL) {
                        list_del_init(&ext->oe_link);
                        osc_extent_finish(env, ext, 0, rc);
                }
@@ -2591,6 +2673,34 @@ out:
        RETURN(rc);
 }
 
+/* This is to refresh our lock in face of no RPCs. */
+void osc_send_empty_rpc(struct osc_object *osc, pgoff_t start)
+{
+       struct ptlrpc_request *req;
+       struct obdo oa;
+       struct brw_page bpg = { .off = start, .count = 1};
+       struct brw_page *pga = &bpg;
+       int rc;
+
+       memset(&oa, 0, sizeof(oa));
+       oa.o_oi = osc->oo_oinfo->loi_oi;
+       oa.o_valid = OBD_MD_FLID | OBD_MD_FLGROUP | OBD_MD_FLFLAGS;
+       /* For updated servers - don't do a read */
+       oa.o_flags = OBD_FL_NORPC;
+
+       rc = osc_brw_prep_request(OBD_BRW_READ, osc_cli(osc), &oa, 1, &pga,
+                                 &req, 0);
+
+       /* If we succeeded we ship it off, if not there's no point in doing
+        * anything. Also no resends.
+        * No interpret callback, no commit callback.
+        */
+       if (!rc) {
+               req->rq_no_resend = 1;
+               ptlrpcd_add_req(req);
+       }
+}
+
 static int osc_set_lock_data(struct ldlm_lock *lock, void *data)
 {
         int set = 0;
@@ -2980,19 +3090,17 @@ static int osc_statfs(const struct lu_env *env, struct obd_export *exp,
        struct obd_device     *obd = class_exp2obd(exp);
        struct obd_statfs     *msfs;
        struct ptlrpc_request *req;
-       struct obd_import     *imp = NULL;
+       struct obd_import     *imp, *imp0;
        int rc;
        ENTRY;
 
-
-        /*Since the request might also come from lprocfs, so we need
-         *sync this with client_disconnect_export Bug15684*/
-       down_read(&obd->u.cli.cl_sem);
-        if (obd->u.cli.cl_import)
-                imp = class_import_get(obd->u.cli.cl_import);
-       up_read(&obd->u.cli.cl_sem);
-        if (!imp)
-                RETURN(-ENODEV);
+       /*Since the request might also come from lprocfs, so we need
+        *sync this with client_disconnect_export Bug15684
+        */
+       with_imp_locked(obd, imp0, rc)
+               imp = class_import_get(imp0);
+       if (rc)
+               RETURN(rc);
 
        /* We could possibly pass max_age in the request (as an absolute
         * timestamp or a "seconds.usec ago") so the target can avoid doing
@@ -3562,21 +3670,28 @@ static const struct obd_ops osc_obd_ops = {
         .o_quotactl             = osc_quotactl,
 };
 
-static struct shrinker *osc_cache_shrinker;
 LIST_HEAD(osc_shrink_list);
 DEFINE_SPINLOCK(osc_shrink_lock);
 
-#ifndef HAVE_SHRINKER_COUNT
-static int osc_cache_shrink(SHRINKER_ARGS(sc, nr_to_scan, gfp_mask))
+#ifdef HAVE_SHRINKER_COUNT
+static struct shrinker osc_cache_shrinker = {
+       .count_objects  = osc_cache_shrink_count,
+       .scan_objects   = osc_cache_shrink_scan,
+       .seeks          = DEFAULT_SEEKS,
+};
+#else
+static int osc_cache_shrink(struct shrinker *shrinker,
+                           struct shrink_control *sc)
 {
-       struct shrink_control scv = {
-               .nr_to_scan = shrink_param(sc, nr_to_scan),
-               .gfp_mask   = shrink_param(sc, gfp_mask)
-       };
-       (void)osc_cache_shrink_scan(shrinker, &scv);
+       (void)osc_cache_shrink_scan(shrinker, sc);
 
-       return osc_cache_shrink_count(shrinker, &scv);
+       return osc_cache_shrink_count(shrinker, sc);
 }
+
+static struct shrinker osc_cache_shrinker = {
+       .shrink   = osc_cache_shrink,
+       .seeks    = DEFAULT_SEEKS,
+};
 #endif
 
 static int __init osc_init(void)
@@ -3584,8 +3699,6 @@ static int __init osc_init(void)
        unsigned int reqpool_size;
        unsigned int reqsize;
        int rc;
-       DEF_SHRINKER_VAR(osc_shvar, osc_cache_shrink,
-                        osc_cache_shrink_count, osc_cache_shrink_scan);
        ENTRY;
 
        /* print an address of _any_ initialized kernel symbol from this
@@ -3597,16 +3710,18 @@ static int __init osc_init(void)
        if (rc)
                RETURN(rc);
 
-       rc = class_register_type(&osc_obd_ops, NULL, true, NULL,
+       rc = class_register_type(&osc_obd_ops, NULL, true,
                                 LUSTRE_OSC_NAME, &osc_device_type);
        if (rc)
                GOTO(out_kmem, rc);
 
-       osc_cache_shrinker = set_shrinker(DEFAULT_SEEKS, &osc_shvar);
+       rc = register_shrinker(&osc_cache_shrinker);
+       if (rc)
+               GOTO(out_type, rc);
 
        /* This is obviously too much memory, only prevent overflow here */
        if (osc_reqpool_mem_max >= 1 << 12 || osc_reqpool_mem_max == 0)
-               GOTO(out_type, rc = -EINVAL);
+               GOTO(out_shrinker, rc = -EINVAL);
 
        reqpool_size = osc_reqpool_mem_max << 20;
 
@@ -3627,7 +3742,7 @@ static int __init osc_init(void)
                                          ptlrpc_add_rqs_to_pool);
 
        if (osc_rq_pool == NULL)
-               GOTO(out_type, rc = -ENOMEM);
+               GOTO(out_shrinker, rc = -ENOMEM);
 
        rc = osc_start_grant_work();
        if (rc != 0)
@@ -3637,6 +3752,8 @@ static int __init osc_init(void)
 
 out_req_pool:
        ptlrpc_free_rq_pool(osc_rq_pool);
+out_shrinker:
+       unregister_shrinker(&osc_cache_shrinker);
 out_type:
        class_unregister_type(LUSTRE_OSC_NAME);
 out_kmem:
@@ -3648,7 +3765,7 @@ out_kmem:
 static void __exit osc_exit(void)
 {
        osc_stop_grant_work();
-       remove_shrinker(osc_cache_shrinker);
+       unregister_shrinker(&osc_cache_shrinker);
        class_unregister_type(LUSTRE_OSC_NAME);
        lu_kmem_fini(osc_caches);
        ptlrpc_free_rq_pool(osc_rq_pool);