From: Niu Yawei Date: Wed, 14 May 2014 09:16:38 +0000 (-0400) Subject: LU-4976 osp: add comments for lwp_dev.c functions X-Git-Tag: 2.6.52~42 X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=9cd8add8b720142766d4036e24202ba9738d0414;hp=0de931bb0c66f397a0d9f4b66830cb1050015c9b;p=fs%2Flustre-release.git LU-4976 osp: add comments for lwp_dev.c functions Add introductory comment block for the lwp_dev.c file. Add function comment blocks to all functions in the lwp_dev.c file. Signed-off-by: Niu Yawei Change-Id: I8a672982964a742d56b1d64e7b8cceb31aa64a48 Reviewed-on: http://review.whamcloud.com/10335 Tested-by: Jenkins Tested-by: Maloo Reviewed-by: Ned Bass Reviewed-by: Richard Henwood Reviewed-by: Oleg Drokin --- diff --git a/lustre/osp/lwp_dev.c b/lustre/osp/lwp_dev.c index 48d654d..7587560 100644 --- a/lustre/osp/lwp_dev.c +++ b/lustre/osp/lwp_dev.c @@ -26,8 +26,13 @@ * * lustre/osp/lwp_dev.c * - * Light Weight Proxy, which is just for managing the connection established - * from OSTs/MDTs to MDT0. + * This file provides code related to the Light Weight Proxy (LWP) managing + * the connections established from OST to MDT, and MDT to MDT0. + * + * A LWP connection is used to send quota and FLD query requests. It's not + * recoverable, which means target server doesn't have an on-disk record in + * the last_rcvd file to remember the connection. Once LWP reconnect after + * server reboot, server will always regard it as a new connection. * * Author: * Author: @@ -41,10 +46,10 @@ struct lwp_device { struct lu_device lpd_dev; - struct obd_device *lpd_obd; - struct obd_uuid lpd_cluuid; - struct obd_export *lpd_exp; - int lpd_connects; + struct obd_device *lpd_obd; /* corresponding OBD device */ + struct obd_uuid lpd_cluuid;/* UUID of LWP */ + struct obd_export *lpd_exp; /* export of LWP */ + int lpd_connects; /* use count, 0 or 1 */ }; static inline struct lwp_device *lu2lwp_dev(struct lu_device *d) @@ -57,6 +62,16 @@ static inline struct lu_device *lwp2lu_dev(struct lwp_device *d) return &d->lpd_dev; } +/** + * Setup LWP device. + * + * \param[in] env environment passed by caller + * \param[in] lwp LWP device to be setup + * \param[in] nidstring remote target NID + * + * \retval 0 on success + * \retval negative number on error + */ static int lwp_setup(const struct lu_env *env, struct lwp_device *lwp, char *nidstring) { @@ -124,6 +139,14 @@ out: RETURN(rc); } +/** + * Disconnect the import from LWP. + * + * \param[in] d LWP device to be disconnected + * + * \retval 0 on success + * \retval negative number on error + */ static int lwp_disconnect(struct lwp_device *d) { struct obd_import *imp; @@ -131,9 +154,12 @@ static int lwp_disconnect(struct lwp_device *d) imp = d->lpd_obd->u.cli.cl_import; - /* Mark import deactivated now, so we don't try to reconnect if any + /* + * Mark import deactivated now, so we don't try to reconnect if any * of the cleanup RPCs fails (e.g. ldlm cancel, etc). We don't - * fully deactivate the import, or that would drop all requests. */ + * fully deactivate the import because that would cause all requests + * to be dropped. + */ LASSERT(imp != NULL); spin_lock(&imp->imp_lock); imp->imp_deactive = 1; @@ -141,9 +167,11 @@ static int lwp_disconnect(struct lwp_device *d) ptlrpc_deactivate_import(imp); - /* Some non-replayable imports (MDS's OSCs) are pinged, so just + /* + * Some non-replayable imports (MDS's OSCs) are pinged, so just * delete it regardless. (It's safe to delete an import that was - * never added.) */ + * never added.) + */ ptlrpc_pinger_del_import(imp); rc = ptlrpc_disconnect_import(imp, 0); if (rc != 0) @@ -155,6 +183,18 @@ static int lwp_disconnect(struct lwp_device *d) RETURN(rc); } +/** + * Implementation of lu_device_operations::ldo_process_config. + * + * Process a Lustre configuration request. + * + * \param[in] env environment passed by caller + * \param[in] dev device to be processed + * \param[in] lcfg lustre_cfg, LCFG_PRE_CLEANUP or LCFG_CLEANUP + * + * \retval 0 on success + * \retval negative number on error + */ static int lwp_process_config(const struct lu_env *env, struct lu_device *dev, struct lustre_cfg *lcfg) { @@ -184,6 +224,18 @@ const struct lu_device_operations lwp_lu_ops = { .ldo_process_config = lwp_process_config, }; +/** + * Initialize LWP device. + * + * \param[in] env environment passed by caller + * \param[in] lwp device to be initialized + * \param[in] ldt not used + * \param[in] cfg lustre_cfg contains remote target uuid + * + * \retval 0 on success + * \retval -ENODEV if the device name cannot be found + * \retval negative numbers on other errors + */ int lwp_init0(const struct lu_env *env, struct lwp_device *lwp, struct lu_device_type *ldt, struct lustre_cfg *cfg) { @@ -221,6 +273,18 @@ int lwp_init0(const struct lu_env *env, struct lwp_device *lwp, RETURN(0); } +/** + * Implementation of lu_device_type_operations::ldto_device_free. + * + * Free a LWP device. + * + * \param[in] env environment passed by caller + * \param[in] lu device to be freed + * + * \retval NULL to indicate that this is the bottom device + * of the stack and there are no more devices + * below this one to be cleaned up. + */ static struct lu_device *lwp_device_free(const struct lu_env *env, struct lu_device *lu) { @@ -236,35 +300,57 @@ static struct lu_device *lwp_device_free(const struct lu_env *env, RETURN(NULL); } +/** + * Implementation of lu_device_type_operations::ldto_device_alloc. + * + * Allocate a LWP device. + * + * \param[in] env environment passed by caller + * \param[in] ldt device type whose name is LUSTRE_LWP_NAME + * \param[in] lcfg lustre_cfg contains remote target UUID + * + * \retval pointer of allocated LWP device on success + * \retval ERR_PTR(errno) on error + */ static struct lu_device *lwp_device_alloc(const struct lu_env *env, - struct lu_device_type *t, + struct lu_device_type *ldt, struct lustre_cfg *lcfg) { struct lwp_device *lwp; - struct lu_device *l; + struct lu_device *ludev; OBD_ALLOC_PTR(lwp); if (lwp == NULL) { - l = ERR_PTR(-ENOMEM); + ludev = ERR_PTR(-ENOMEM); } else { int rc; - l = lwp2lu_dev(lwp); - lu_device_init(&lwp->lpd_dev, t); - rc = lwp_init0(env, lwp, t, lcfg); + ludev = lwp2lu_dev(lwp); + lu_device_init(&lwp->lpd_dev, ldt); + rc = lwp_init0(env, lwp, ldt, lcfg); if (rc != 0) { - lwp_device_free(env, l); - l = ERR_PTR(rc); + lwp_device_free(env, ludev); + ludev = ERR_PTR(rc); } } - return l; + return ludev; } +/** + * Implementation of lu_device_type_operations::ltdo_device_fini. + * + * Finalize LWP device. + * + * \param[in] env environment passed by caller + * \param[in] ludev device to be finalized + * + * \retval NULL on success + */ static struct lu_device *lwp_device_fini(const struct lu_env *env, - struct lu_device *d) + struct lu_device *ludev) { - struct lwp_device *m = lu2lwp_dev(d); + struct lwp_device *m = lu2lwp_dev(ludev); struct obd_import *imp; int rc; ENTRY; @@ -304,6 +390,21 @@ struct lu_device_type lwp_device_type = { .ldt_ctx_tags = LCT_MD_THREAD }; +/** + * Implementation of OBD device operations obd_ops::o_connect. + * + * Create export for LWP, and connect to target server. + * + * \param[in] env the environment passed by caller + * \param[out] exp export for the connection to be established + * \param[in] obd OBD device to perform the connect on + * \param[in] cluuid UUID of the OBD device + * \param[in] data connect data containing compatibility flags + * \param[in] localdata not used + * + * \retval 0 on success + * \retval negative number on error + */ static int lwp_obd_connect(const struct lu_env *env, struct obd_export **exp, struct obd_device *obd, struct obd_uuid *cluuid, struct obd_connect_data *data, void *localdata) @@ -328,7 +429,6 @@ static int lwp_obd_connect(const struct lu_env *env, struct obd_export **exp, *exp = class_conn2export(&conn); lwp->lpd_exp = *exp; - /* Why should there ever be more than 1 connect? */ lwp->lpd_connects++; LASSERT(lwp->lpd_connects == 1); @@ -369,6 +469,17 @@ out_sem: return rc; } +/** + * Implementation of OBD device operations obd_ops::o_disconnect. + * + * Release export for the LWP. Only disconnect the underlying layers + * on the final disconnect. + * + * \param[in] exp the export to perform disconnect on + * + * \retval 0 on success + * \retval negative number on error + */ static int lwp_obd_disconnect(struct obd_export *exp) { struct obd_device *obd = exp->exp_obd; @@ -376,7 +487,6 @@ static int lwp_obd_disconnect(struct obd_export *exp) int rc; ENTRY; - /* Only disconnect the underlying layers on the final disconnect. */ LASSERT(lwp->lpd_connects == 1); lwp->lpd_connects--; @@ -388,6 +498,16 @@ static int lwp_obd_disconnect(struct obd_export *exp) RETURN(rc); } +/** + * Handle import events for the LWP device. + * + * \param[in] obd OBD device associated with the import + * \param[in] imp the import which event happened on + * \param[in] event event type + * + * \retval 0 on success + * \retval negative number on error + */ static int lwp_import_event(struct obd_device *obd, struct obd_import *imp, enum obd_import_event event) {