X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=blobdiff_plain;f=lustre%2Fofd%2Fofd_grant.c;h=ff205f5cad48d2b6dc732c745114eaaf86926761;hp=a1819fc3bba59be1b2fbdce39566f4a8224a7ad0;hb=b808da75ffe27b6199c636ff216817e12c6d3fa6;hpb=19075957acebe990aa124a68a27d5c1e9d5d20e0 diff --git a/lustre/ofd/ofd_grant.c b/lustre/ofd/ofd_grant.c index a1819fc..ff205f5 100644 --- a/lustre/ofd/ofd_grant.c +++ b/lustre/ofd/ofd_grant.c @@ -15,11 +15,7 @@ * * You should have received a copy of the GNU General Public License * version 2 along with this program; If not, see - * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf - * - * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, - * CA 95054 USA or visit www.sun.com if you need additional information or - * have any questions. + * http://www.gnu.org/licenses/gpl-2.0.html * * GPL HEADER END */ @@ -27,15 +23,31 @@ * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved. * Use is subject to license terms. * - * Copyright (c) 2012, 2013, Intel Corporation. + * Copyright (c) 2012, 2014, Intel Corporation. */ /* * This file is part of Lustre, http://www.lustre.org/ * Lustre is a trademark of Sun Microsystems, Inc. - * + */ +/* * lustre/ofd/ofd_grant.c * - * Author: Johann Lombardi + * This file provides code related to grant space management on Object Storage + * Targets (OSTs). Grant is a mechanism used by client nodes to reserve disk + * space on OSTs for the data writeback cache. The Lustre client is thus assured + * that enough space will be available when flushing dirty pages asynchronously. + * Each client node is granted an initial amount of reserved space at connect + * time and gets additional space back from OST in bulk write reply. + * + * This file handles the core logic for: + * - grant allocation strategy + * - maintaining per-client as well as global grant space accounting + * - processing grant information packed in incoming requests + * - allocating server-side grant space for synchronous write RPCs which did not + * consume grant on the client side (OBD_BRW_FROM_GRANT flag not set). If not + * enough space is available, such RPCs fail with ENOSPC + * + * Author: Johann Lombardi */ #define DEBUG_SUBSYSTEM S_FILTER @@ -84,24 +96,31 @@ static inline obd_size ofd_grant_chunk(struct obd_export *exp, } /** - * Perform extra sanity checks for grant accounting. This is done at connect, - * disconnect, and statfs RPC time, so it shouldn't be too bad. We can - * always get rid of it or turn it off when we know accounting is good. + * Perform extra sanity checks for grant accounting. * - * \param obd - is the device to check - * \param func - is the function to call if an inconsistency is found + * This function scans the export list, sanity checks per-export grant counters + * and verifies accuracy of global grant accounting. If an inconsistency is + * found, a CERROR is printed with the function name \func that was passed as + * argument. LBUG is only called in case of serious counter corruption (i.e. + * value larger than the device size). + * Those sanity checks can be pretty expensive and are disabled if the OBD + * device has more than 100 connected exports. + * + * \param[in] obd OBD device for which grant accounting should be + * verified + * \param[in] func caller's function name */ void ofd_grant_sanity_check(struct obd_device *obd, const char *func) { - struct filter_export_data *fed; - struct ofd_device *ofd = ofd_dev(obd->obd_lu_dev); - struct obd_export *exp; - obd_size maxsize; - obd_size tot_dirty = 0; - obd_size tot_pending = 0; - obd_size tot_granted = 0; - obd_size fo_tot_dirty, fo_tot_pending; - obd_size fo_tot_granted; + struct ofd_device *ofd = ofd_dev(obd->obd_lu_dev); + struct obd_export *exp; + obd_size maxsize; + obd_size tot_dirty = 0; + obd_size tot_pending = 0; + obd_size tot_granted = 0; + obd_size fo_tot_granted; + obd_size fo_tot_pending; + obd_size fo_tot_dirty; if (cfs_list_empty(&obd->obd_exports)) return; @@ -116,7 +135,8 @@ void ofd_grant_sanity_check(struct obd_device *obd, const char *func) spin_lock(&obd->obd_dev_lock); spin_lock(&ofd->ofd_grant_lock); cfs_list_for_each_entry(exp, &obd->obd_exports, exp_obd_chain) { - int error = 0; + struct filter_export_data *fed; + int error = 0; fed = &exp->exp_filter_data; @@ -180,15 +200,19 @@ void ofd_grant_sanity_check(struct obd_device *obd, const char *func) } /** - * Get fresh statfs information from the OSD layer if the cache is older than 1s - * or if force is set. The OSD layer is in charge of estimating data & metadata - * overhead. + * Update cached statfs information from the OSD layer * - * \param env - is the lu environment passed by the caller - * \param exp - export used to print client info in debug messages - * \param force - is used to force a refresh of statfs information - * \param from_cache - returns whether the statfs information are - * taken from cache + * Refresh statfs information cached in ofd::ofd_osfs if the cache is older + * than 1s or if force is set. The OSD layer is in charge of estimating data & + * metadata overhead. + * This function can sleep so it should not be called with any spinlock held. + * + * \param[in] env LU environment passed by the caller + * \param[in] exp export used to print client info in debug + * messages + * \param[in] force force a refresh of statfs information + * \param[out] from_cache returns whether the statfs information are + * taken from cache */ static void ofd_grant_statfs(const struct lu_env *env, struct obd_export *exp, int force, int *from_cache) @@ -218,19 +242,25 @@ static void ofd_grant_statfs(const struct lu_env *env, struct obd_export *exp, } /** - * Figure out how much space is available on the backend filesystem. + * Figure out how much space is available on the backend filesystem after + * removing grant space already booked by clients. + * * This is done by accessing cached statfs data previously populated by * ofd_grant_statfs(), from which we withdraw the space already granted to * clients and the reserved space. + * Caller must hold ofd_grant_lock spinlock. * - * \param exp - export which received the write request + * \param[in] exp export associated with the device for which the amount + * of available space is requested + * \retval amount of non-allocated space, in bytes */ static obd_size ofd_grant_space_left(struct obd_export *exp) { struct obd_device *obd = exp->exp_obd; struct ofd_device *ofd = ofd_exp(exp); obd_size tot_granted; - obd_size left, avail; + obd_size left; + obd_size avail; obd_size unstable; ENTRY; @@ -282,13 +312,16 @@ static obd_size ofd_grant_space_left(struct obd_export *exp) } /** + * Process grant information from obdo structure packed in incoming BRW + * * Grab the dirty and seen grant announcements from the incoming obdo. * We will later calculate the client's new grant and return it. * Caller must hold ofd_grant_lock spinlock. * - * \param env - is the lu environment supplying osfs storage - * \param exp - is the export for which we received the request - * \paral oa - is the incoming obdo sent by the client + * \param[in] env LU environment supplying osfs storage + * \param[in] exp export for which we received the request + * \param[in,out] oa incoming obdo sent by the client + * */ static void ofd_grant_incoming(const struct lu_env *env, struct obd_export *exp, struct obdo *oa) @@ -296,7 +329,9 @@ static void ofd_grant_incoming(const struct lu_env *env, struct obd_export *exp, struct filter_export_data *fed; struct ofd_device *ofd = ofd_exp(exp); struct obd_device *obd = exp->exp_obd; - long dirty, dropped, grant_chunk; + long dirty; + long dropped; + long grant_chunk; ENTRY; assert_spin_locked(&ofd->ofd_grant_lock); @@ -359,18 +394,21 @@ static void ofd_grant_incoming(const struct lu_env *env, struct obd_export *exp, } /** - * Called when the client is able to release some grants. Proceed with the - * shrink request when there is less ungranted space remaining - * than the amount all of the connected clients would consume if they - * used their full grant. + * Grant shrink request handler. + * + * Client nodes can explicitly release grant space (i.e. process called grant + * shrinking). This function proceeds with the shrink request when there is + * less ungranted space remaining than the amount all of the connected clients + * would consume if they used their full grant. + * Caller must hold ofd_grant_lock spinlock. * - * \param exp - is the export for which we received the request - * \paral oa - is the incoming obdo sent by the client - * \param left_space - is the remaining free space with space already granted - * taken out + * \param[in] exp export releasing grant space + * \param[in,out] oa incoming obdo sent by the client + * \param[in] left_space remaining free space with space already granted + * taken out */ -static void ofd_grant_shrink(struct obd_export *exp, - struct obdo *oa, obd_size left_space) +static void ofd_grant_shrink(struct obd_export *exp, struct obdo *oa, + obd_size left_space) { struct filter_export_data *fed; struct ofd_device *ofd = ofd_exp(exp); @@ -399,12 +437,27 @@ static void ofd_grant_shrink(struct obd_export *exp, /** * Calculate how much space is required to write a given network buffer + * + * This function takes block alignment into account to estimate how much on-disk + * space will be required to successfully write the whole niobuf. + * Estimated space is inflated if the export does not support + * OBD_CONNECT_GRANT_PARAM and if the backend filesystem has a block size + * larger than the minimal supported page size (i.e. 4KB). + * + * \param[in] exp export associated which the write request + * \param[in] ofd ofd device handling the request + * \param[in] rnb network buffer to estimate size of + * + * \retval space (in bytes) that will be consumed to write the + * network buffer */ static inline int ofd_grant_rnb_size(struct obd_export *exp, struct ofd_device *ofd, struct niobuf_remote *rnb) { - obd_size blocksize, bytes, end; + obd_size blocksize; + obd_size bytes; + obd_size end; if (exp && ofd_grant_compat(exp, ofd)) blocksize = 1ULL << COMPAT_BSIZE_SHIFT; @@ -424,24 +477,28 @@ static inline int ofd_grant_rnb_size(struct obd_export *exp, return bytes; } - /** + * Validate grant accounting for each incoming remote network buffer. + * * When clients have dirtied as much space as they've been granted they - * fall through to sync writes. These sync writes haven't been expressed + * fall through to sync writes. These sync writes haven't been expressed * in grants and need to error with ENOSPC when there isn't room in the - * filesystem for them after grants are taken into account. However, + * filesystem for them after grants are taken into account. However, * writeback of the dirty data that was already granted space can write * right on through. + * The OBD_BRW_GRANTED flag will be set in the rnb_flags of each network + * buffer which has been granted enough space to proceed. Buffers without + * this flag will fail to be written with -ENOSPC (see ofd_preprw_write(). * Caller must hold ofd_grant_lock spinlock. * - * \param env - is the lu environment passed by the caller - * \param exp - is the export identifying the client which sent the RPC - * \param oa - is the incoming obdo in which we should return the pack the - * additional grant - * \param rnb - is the list of network buffers - * \param niocont - is the number of network buffers in the list - * \param left - is the remaining free space with space already granted - * taken out + * \param[in] env LU environment passed by the caller + * \param[in] exp export identifying the client which sent the RPC + * \param[in] oa incoming obdo in which we should return the pack the + * additional grant + * \param[in,out] rnb the list of network buffers + * \param[in] niocont the number of network buffers in the list + * \param[in] left the remaining free space with space already granted + * taken out */ static void ofd_grant_check(const struct lu_env *env, struct obd_export *exp, struct obdo *oa, struct niobuf_remote *rnb, @@ -579,19 +636,27 @@ static void ofd_grant_check(const struct lu_env *env, struct obd_export *exp, } /** + * Allocate additional grant space to a client + * * Calculate how much grant space to return to client, based on how much space * is currently free and how much of that is already granted. * Caller must hold ofd_grant_lock spinlock. * - * \param exp - is the export of the client which sent the request - * \param curgrant - is the current grant claimed by the client - * \param want - is how much grant space the client would like to have - * \param left - is the remaining free space with granted space taken out - * \param conservative - is how server grants, if true, a certain amount, else - * server will grant as client requested. + * \param[in] exp export of the client which sent the request + * \param[in] curgrant current grant claimed by the client + * \param[in] want how much grant space the client would like to + * have + * \param[in] left remaining free space with granted space taken + * out + * \param[in] conservative if set to true, the server should be cautious + * and limit how much space is granted back to the + * client. Otherwise, the server should try hard to + * satisfy the client request. + * + * \retval amount of grant space allocated */ -static long ofd_grant(struct obd_export *exp, obd_size curgrant, - obd_size want, obd_size left, bool conservative) +static long ofd_grant_alloc(struct obd_export *exp, obd_size curgrant, + obd_size want, obd_size left, bool conservative) { struct obd_device *obd = exp->exp_obd; struct ofd_device *ofd = ofd_exp(exp); @@ -672,17 +737,23 @@ static long ofd_grant(struct obd_export *exp, obd_size curgrant, } /** - * Client connection or reconnection. + * Handle grant space allocation on client connection & reconnection. * - * \param env - is the lu environment provided by the caller - * \param exp - is the client's export which is reconnecting - * \param want - is how much the client would like to get - * \param conservative - is how server grants to client, if true server will - * only grant certain amount, else server will grant client requested - * amount. + * A new non-readonly connection gets an initial grant allocation equals to + * ofd_grant_chunk() (i.e. twice the max BRW size in most of the cases). + * On reconnection, grant counters between client & OST are resynchronized + * and additional space might be granted back if possible. + * + * \param[in] env LU environment provided by the caller + * \param[in] exp client's export which is (re)connecting + * \param[in] want how much grant space the client would like to get + * \param[in] new_conn must set to true if this is a new connection and false + * for a reconnection + * + * \retval amount of grant space currently owned by the client */ long ofd_grant_connect(const struct lu_env *env, struct obd_export *exp, - obd_size want, bool conservative) + obd_size want, bool new_conn) { struct ofd_device *ofd = ofd_exp(exp); struct filter_export_data *fed = &exp->exp_filter_data; @@ -713,8 +784,9 @@ refresh: goto refresh; } - ofd_grant(exp, ofd_grant_to_cli(exp, ofd, (obd_size)fed->fed_grant), - want, left, conservative); + ofd_grant_alloc(exp, + ofd_grant_to_cli(exp, ofd, (obd_size)fed->fed_grant), + want, left, new_conn); /* return to client its current grant */ grant = ofd_grant_to_cli(exp, ofd, (obd_size)fed->fed_grant); @@ -730,12 +802,14 @@ refresh: } /** + * Release all grant space attached to a given export. + * * Remove a client from the grant accounting totals. We also remove * the export from the obd device under the osfs and dev locks to ensure * that the ofd_grant_sanity_check() calculations are always valid. * The client should do something similar when it invalidates its import. * - * \param exp - is the client's export to remove from grant accounting + * \param[in] exp client's export to remove from grant accounting */ void ofd_grant_discard(struct obd_export *exp) { @@ -766,13 +840,17 @@ void ofd_grant_discard(struct obd_export *exp) } /** - * Called at prepare time when handling read request. This function extracts - * incoming grant information from the obdo and processes the grant shrink - * request, if any. + * Process grant information from incoming bulk read request. + * + * Extract grant information packed in obdo structure (OBD_MD_FLGRANT set in + * o_valid). Bulk reads usually comes with grant announcements (number of dirty + * blocks, remaining amount of grant space, ...) and could also include a grant + * shrink request. Unlike bulk write, no additional grant space is returned on + * bulk read request. * - * \param env - is the lu environment provided by the caller - * \param exp - is the export of the client which sent the request - * \paral oa - is the incoming obdo sent by the client + * \param[in] env is the lu environment provided by the caller + * \param[in] exp is the export of the client which sent the request + * \paral[in,out] oa is the incoming obdo sent by the client */ void ofd_grant_prepare_read(const struct lu_env *env, struct obd_export *exp, struct obdo *oa) @@ -829,14 +907,25 @@ void ofd_grant_prepare_read(const struct lu_env *env, } /** - * Called at write prepare time to handle incoming grant, check that we have - * enough space and grant some space back to the client if possible. + * Process grant information from incoming bulk write request. * - * \param env - is the lu environment provided by the caller - * \param exp - is the export of the client which sent the request - * \paral oa - is the incoming obdo sent by the client - * \param rnb - is the list of network buffers - * \param niocont - is the number of network buffers in the list + * This function extracts client's grant announcements from incoming bulk write + * request and attempts to allocate grant space for network buffers that need it + * (i.e. OBD_BRW_FROM_GRANT not set in rnb_fags). + * Network buffers which aren't granted the OBD_BRW_GRANTED flag should not + * proceed further and should fail with -ENOSPC. + * Whenever possible, additional grant space will be returned to the client + * in the bulk write reply. + * ofd_grant_prepare_write() must be called before writting any buffers to + * the backend storage. This function works in pair with ofd_grant_commit() + * which must be invoked once all buffers have been written to disk in order + * to release space from the pending grant counter. + * + * \param[in] env LU environment provided by the caller + * \param[in] exp export of the client which sent the request + * \param[in] oa incoming obdo sent by the client + * \param[in] rnb list of network buffers + * \param[in] niocont number of network buffers in the list */ void ofd_grant_prepare_write(const struct lu_env *env, struct obd_export *exp, struct obdo *oa, @@ -913,19 +1002,28 @@ refresh: ofd_grant_shrink(exp, oa, left); else /* grant more space back to the client if possible */ - oa->o_grant = ofd_grant(exp, oa->o_grant, oa->o_undirty, left, - true); + oa->o_grant = ofd_grant_alloc(exp, oa->o_grant, oa->o_undirty, + left, true); spin_unlock(&ofd->ofd_grant_lock); } /** - * Called during object precreation to consume grant space. - * More space is granted for precreation if possible. + * Consume grant space reserved for object creation. + * + * Grant space is allocated to the local self export for object precreation. + * This is required to prevent object precreation from consuming grant space + * allocated to client nodes for the data writeback cache. + * This function consumes enough space to create \a nr objects and allocates + * more grant space to the self export for future precreation requests, if + * possible. * - * \param env - is the lu environment provided by the caller - * \param exp - is the export holding the grant space for precreation (= self - * export currently) - * \paral nr - is the number of objects the caller wants to create objects + * \param[in] env LU environment provided by the caller + * \param[in] exp export holding the grant space for precreation (= self + * export currently) + * \param[in] nr number of objects to be created + * + * \retval 0 for success + * \retval -ENOSPC on failure */ int ofd_grant_create(const struct lu_env *env, struct obd_export *exp, int *nr) { @@ -1002,17 +1100,19 @@ int ofd_grant_create(const struct lu_env *env, struct obd_export *exp, int *nr) /* always try to book enough space to handle a large precreate * request */ wanted -= fed->fed_grant; - ofd_grant(exp, fed->fed_grant, wanted, left, false); + ofd_grant_alloc(exp, fed->fed_grant, wanted, left, false); } spin_unlock(&ofd->ofd_grant_lock); RETURN(0); } /** - * Called at commit time to update pending grant counter for writes in flight + * Release grant space added to the pending counter by ofd_grant_prepare_write() + * + * Update pending grant counter once buffers have been written to the disk. * - * \param env - is the lu environment provided by the caller - * \param exp - is the export of the client which sent the request + * \param[in] env LU environment provided by the caller + * \param[in] exp export of the client which sent the request */ void ofd_grant_commit(const struct lu_env *env, struct obd_export *exp, int rc)