1
/* AFS volume location management
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* Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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static unsigned afs_vlocation_timeout = 10; /* volume location timeout in seconds */
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static unsigned afs_vlocation_update_timeout = 10 * 60;
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static void afs_vlocation_reaper(struct work_struct *);
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static void afs_vlocation_updater(struct work_struct *);
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static LIST_HEAD(afs_vlocation_updates);
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static LIST_HEAD(afs_vlocation_graveyard);
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static DEFINE_SPINLOCK(afs_vlocation_updates_lock);
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static DEFINE_SPINLOCK(afs_vlocation_graveyard_lock);
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static DECLARE_DELAYED_WORK(afs_vlocation_reap, afs_vlocation_reaper);
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static DECLARE_DELAYED_WORK(afs_vlocation_update, afs_vlocation_updater);
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static struct workqueue_struct *afs_vlocation_update_worker;
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* iterate through the VL servers in a cell until one of them admits knowing
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* about the volume in question
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static int afs_vlocation_access_vl_by_name(struct afs_vlocation *vl,
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struct afs_cache_vlocation *vldb)
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struct afs_cell *cell = vl->cell;
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_enter("%s,%s", cell->name, vl->vldb.name);
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down_write(&vl->cell->vl_sem);
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for (count = cell->vl_naddrs; count > 0; count--) {
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addr = cell->vl_addrs[cell->vl_curr_svix];
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_debug("CellServ[%hu]: %08x", cell->vl_curr_svix, addr.s_addr);
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/* attempt to access the VL server */
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ret = afs_vl_get_entry_by_name(&addr, key, vl->vldb.name, vldb,
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if (ret == -ENOMEM || ret == -ENONET)
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/* rotate the server records upon lookup failure */
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cell->vl_curr_svix %= cell->vl_naddrs;
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up_write(&vl->cell->vl_sem);
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* iterate through the VL servers in a cell until one of them admits knowing
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* about the volume in question
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static int afs_vlocation_access_vl_by_id(struct afs_vlocation *vl,
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afs_voltype_t voltype,
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struct afs_cache_vlocation *vldb)
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struct afs_cell *cell = vl->cell;
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_enter("%s,%x,%d,", cell->name, volid, voltype);
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down_write(&vl->cell->vl_sem);
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for (count = cell->vl_naddrs; count > 0; count--) {
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addr = cell->vl_addrs[cell->vl_curr_svix];
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_debug("CellServ[%hu]: %08x", cell->vl_curr_svix, addr.s_addr);
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/* attempt to access the VL server */
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ret = afs_vl_get_entry_by_id(&addr, key, volid, voltype, vldb,
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if (ret == -ENOMEM || ret == -ENONET)
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if (vl->upd_busy_cnt <= 3) {
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if (vl->upd_busy_cnt > 1) {
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/* second+ BUSY - sleep a little bit */
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set_current_state(TASK_UNINTERRUPTIBLE);
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__set_current_state(TASK_RUNNING);
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/* rotate the server records upon lookup failure */
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cell->vl_curr_svix++;
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cell->vl_curr_svix %= cell->vl_naddrs;
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vl->upd_busy_cnt = 0;
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if (ret < 0 && vl->upd_rej_cnt > 0) {
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printk(KERN_NOTICE "kAFS:"
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" Active volume no longer valid '%s'\n",
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up_write(&vl->cell->vl_sem);
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_leave(" = %d", ret);
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* allocate a volume location record
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static struct afs_vlocation *afs_vlocation_alloc(struct afs_cell *cell,
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struct afs_vlocation *vl;
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vl = kzalloc(sizeof(struct afs_vlocation), GFP_KERNEL);
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vl->state = AFS_VL_NEW;
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atomic_set(&vl->usage, 1);
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INIT_LIST_HEAD(&vl->link);
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INIT_LIST_HEAD(&vl->grave);
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INIT_LIST_HEAD(&vl->update);
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init_waitqueue_head(&vl->waitq);
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spin_lock_init(&vl->lock);
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memcpy(vl->vldb.name, name, namesz);
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* update record if we found it in the cache
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static int afs_vlocation_update_record(struct afs_vlocation *vl,
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struct afs_cache_vlocation *vldb)
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afs_voltype_t voltype;
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/* try to look up a cached volume in the cell VL databases by ID */
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_debug("Locally Cached: %s %02x { %08x(%x) %08x(%x) %08x(%x) }",
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ntohl(vl->vldb.servers[0].s_addr),
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vl->vldb.srvtmask[0],
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ntohl(vl->vldb.servers[1].s_addr),
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vl->vldb.srvtmask[1],
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ntohl(vl->vldb.servers[2].s_addr),
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vl->vldb.srvtmask[2]);
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_debug("Vids: %08x %08x %08x",
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if (vl->vldb.vidmask & AFS_VOL_VTM_RW) {
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vid = vl->vldb.vid[0];
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voltype = AFSVL_RWVOL;
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} else if (vl->vldb.vidmask & AFS_VOL_VTM_RO) {
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vid = vl->vldb.vid[1];
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voltype = AFSVL_ROVOL;
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} else if (vl->vldb.vidmask & AFS_VOL_VTM_BAK) {
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vid = vl->vldb.vid[2];
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voltype = AFSVL_BACKVOL;
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/* contact the server to make sure the volume is still available
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* - TODO: need to handle disconnected operation here
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ret = afs_vlocation_access_vl_by_id(vl, key, vid, voltype, vldb);
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printk(KERN_WARNING "kAFS:"
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" failed to update volume '%s' (%x) up in '%s': %d\n",
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vl->vldb.name, vid, vl->cell->name, ret);
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_leave(" = %d", ret);
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/* pulled from local cache into memory */
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/* uh oh... looks like the volume got deleted */
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printk(KERN_ERR "kAFS:"
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" volume '%s' (%x) does not exist '%s'\n",
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vl->vldb.name, vid, vl->cell->name);
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/* TODO: make existing record unavailable */
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_leave(" = %d", ret);
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* apply the update to a VL record
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static void afs_vlocation_apply_update(struct afs_vlocation *vl,
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struct afs_cache_vlocation *vldb)
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_debug("Done VL Lookup: %s %02x { %08x(%x) %08x(%x) %08x(%x) }",
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vldb->name, vldb->vidmask,
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ntohl(vldb->servers[0].s_addr), vldb->srvtmask[0],
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ntohl(vldb->servers[1].s_addr), vldb->srvtmask[1],
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ntohl(vldb->servers[2].s_addr), vldb->srvtmask[2]);
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_debug("Vids: %08x %08x %08x",
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vldb->vid[0], vldb->vid[1], vldb->vid[2]);
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if (strcmp(vldb->name, vl->vldb.name) != 0)
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printk(KERN_NOTICE "kAFS:"
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" name of volume '%s' changed to '%s' on server\n",
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vl->vldb.name, vldb->name);
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#ifdef CONFIG_AFS_FSCACHE
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fscache_update_cookie(vl->cache);
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* fill in a volume location record, consulting the cache and the VL server
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static int afs_vlocation_fill_in_record(struct afs_vlocation *vl,
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struct afs_cache_vlocation vldb;
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ASSERTCMP(vl->valid, ==, 0);
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memset(&vldb, 0, sizeof(vldb));
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/* see if we have an in-cache copy (will set vl->valid if there is) */
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#ifdef CONFIG_AFS_FSCACHE
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vl->cache = fscache_acquire_cookie(vl->cell->cache,
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&afs_vlocation_cache_index_def, vl);
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/* try to update a known volume in the cell VL databases by
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* ID as the name may have changed */
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_debug("found in cache");
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ret = afs_vlocation_update_record(vl, key, &vldb);
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/* try to look up an unknown volume in the cell VL databases by
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ret = afs_vlocation_access_vl_by_name(vl, key, &vldb);
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printk("kAFS: failed to locate '%s' in cell '%s'\n",
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vl->vldb.name, vl->cell->name);
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afs_vlocation_apply_update(vl, &vldb);
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* queue a vlocation record for updates
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static void afs_vlocation_queue_for_updates(struct afs_vlocation *vl)
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struct afs_vlocation *xvl;
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/* wait at least 10 minutes before updating... */
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vl->update_at = get_seconds() + afs_vlocation_update_timeout;
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spin_lock(&afs_vlocation_updates_lock);
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if (!list_empty(&afs_vlocation_updates)) {
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/* ... but wait at least 1 second more than the newest record
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* already queued so that we don't spam the VL server suddenly
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* with lots of requests
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xvl = list_entry(afs_vlocation_updates.prev,
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struct afs_vlocation, update);
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if (vl->update_at <= xvl->update_at)
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vl->update_at = xvl->update_at + 1;
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queue_delayed_work(afs_vlocation_update_worker,
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&afs_vlocation_update,
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afs_vlocation_update_timeout * HZ);
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list_add_tail(&vl->update, &afs_vlocation_updates);
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spin_unlock(&afs_vlocation_updates_lock);
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* lookup volume location
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* - iterate through the VL servers in a cell until one of them admits knowing
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* about the volume in question
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* - lookup in the local cache if not able to find on the VL server
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* - insert/update in the local cache if did get a VL response
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struct afs_vlocation *afs_vlocation_lookup(struct afs_cell *cell,
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struct afs_vlocation *vl;
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_enter("{%s},{%x},%*.*s,%zu",
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cell->name, key_serial(key),
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(int) namesz, (int) namesz, name, namesz);
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if (namesz >= sizeof(vl->vldb.name)) {
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_leave(" = -ENAMETOOLONG");
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return ERR_PTR(-ENAMETOOLONG);
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/* see if we have an in-memory copy first */
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down_write(&cell->vl_sem);
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spin_lock(&cell->vl_lock);
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list_for_each_entry(vl, &cell->vl_list, link) {
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if (vl->vldb.name[namesz] != '\0')
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if (memcmp(vl->vldb.name, name, namesz) == 0)
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goto found_in_memory;
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spin_unlock(&cell->vl_lock);
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/* not in the cell's in-memory lists - create a new record */
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vl = afs_vlocation_alloc(cell, name, namesz);
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up_write(&cell->vl_sem);
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return ERR_PTR(-ENOMEM);
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list_add_tail(&vl->link, &cell->vl_list);
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vl->state = AFS_VL_CREATING;
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up_write(&cell->vl_sem);
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ret = afs_vlocation_fill_in_record(vl, key);
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spin_lock(&vl->lock);
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vl->state = AFS_VL_VALID;
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spin_unlock(&vl->lock);
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/* update volume entry in local cache */
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#ifdef CONFIG_AFS_FSCACHE
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fscache_update_cookie(vl->cache);
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/* schedule for regular updates */
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afs_vlocation_queue_for_updates(vl);
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/* found in memory */
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_debug("found in memory");
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atomic_inc(&vl->usage);
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spin_unlock(&cell->vl_lock);
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if (!list_empty(&vl->grave)) {
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spin_lock(&afs_vlocation_graveyard_lock);
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list_del_init(&vl->grave);
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spin_unlock(&afs_vlocation_graveyard_lock);
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up_write(&cell->vl_sem);
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/* see if it was an abandoned record that we might try filling in */
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spin_lock(&vl->lock);
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while (vl->state != AFS_VL_VALID) {
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afs_vlocation_state_t state = vl->state;
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_debug("invalid [state %d]", state);
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if (state == AFS_VL_NEW || state == AFS_VL_NO_VOLUME) {
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vl->state = AFS_VL_CREATING;
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spin_unlock(&vl->lock);
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/* must now wait for creation or update by someone else to
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spin_unlock(&vl->lock);
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ret = wait_event_interruptible(vl->waitq,
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vl->state == AFS_VL_NEW ||
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vl->state == AFS_VL_VALID ||
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vl->state == AFS_VL_NO_VOLUME);
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spin_lock(&vl->lock);
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spin_unlock(&vl->lock);
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spin_lock(&vl->lock);
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vl->state = AFS_VL_NEW;
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spin_unlock(&vl->lock);
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afs_put_vlocation(vl);
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_leave(" = %d", ret);
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* finish using a volume location record
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void afs_put_vlocation(struct afs_vlocation *vl)
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_enter("%s", vl->vldb.name);
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ASSERTCMP(atomic_read(&vl->usage), >, 0);
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if (likely(!atomic_dec_and_test(&vl->usage))) {
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spin_lock(&afs_vlocation_graveyard_lock);
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if (atomic_read(&vl->usage) == 0) {
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list_move_tail(&vl->grave, &afs_vlocation_graveyard);
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vl->time_of_death = get_seconds();
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queue_delayed_work(afs_wq, &afs_vlocation_reap,
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afs_vlocation_timeout * HZ);
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/* suspend updates on this record */
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if (!list_empty(&vl->update)) {
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spin_lock(&afs_vlocation_updates_lock);
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list_del_init(&vl->update);
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spin_unlock(&afs_vlocation_updates_lock);
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spin_unlock(&afs_vlocation_graveyard_lock);
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_leave(" [killed?]");
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* destroy a dead volume location record
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static void afs_vlocation_destroy(struct afs_vlocation *vl)
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#ifdef CONFIG_AFS_FSCACHE
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fscache_relinquish_cookie(vl->cache, 0);
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afs_put_cell(vl->cell);
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* reap dead volume location records
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static void afs_vlocation_reaper(struct work_struct *work)
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struct afs_vlocation *vl;
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unsigned long delay, expiry;
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spin_lock(&afs_vlocation_graveyard_lock);
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while (!list_empty(&afs_vlocation_graveyard)) {
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vl = list_entry(afs_vlocation_graveyard.next,
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struct afs_vlocation, grave);
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_debug("check %p", vl);
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/* the queue is ordered most dead first */
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expiry = vl->time_of_death + afs_vlocation_timeout;
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delay = (expiry - now) * HZ;
563
_debug("delay %lu", delay);
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if (!queue_delayed_work(afs_wq, &afs_vlocation_reap,
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cancel_delayed_work(&afs_vlocation_reap);
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queue_delayed_work(afs_wq, &afs_vlocation_reap,
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spin_lock(&vl->cell->vl_lock);
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if (atomic_read(&vl->usage) > 0) {
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list_del_init(&vl->grave);
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list_move_tail(&vl->grave, &corpses);
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list_del_init(&vl->link);
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spin_unlock(&vl->cell->vl_lock);
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spin_unlock(&afs_vlocation_graveyard_lock);
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/* now reap the corpses we've extracted */
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while (!list_empty(&corpses)) {
589
vl = list_entry(corpses.next, struct afs_vlocation, grave);
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list_del(&vl->grave);
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afs_vlocation_destroy(vl);
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* initialise the VL update process
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int __init afs_vlocation_update_init(void)
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afs_vlocation_update_worker =
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create_singlethread_workqueue("kafs_vlupdated");
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return afs_vlocation_update_worker ? 0 : -ENOMEM;
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* discard all the volume location records for rmmod
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void afs_vlocation_purge(void)
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afs_vlocation_timeout = 0;
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spin_lock(&afs_vlocation_updates_lock);
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list_del_init(&afs_vlocation_updates);
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spin_unlock(&afs_vlocation_updates_lock);
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cancel_delayed_work(&afs_vlocation_update);
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queue_delayed_work(afs_vlocation_update_worker,
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&afs_vlocation_update, 0);
620
destroy_workqueue(afs_vlocation_update_worker);
622
cancel_delayed_work(&afs_vlocation_reap);
623
queue_delayed_work(afs_wq, &afs_vlocation_reap, 0);
627
* update a volume location
629
static void afs_vlocation_updater(struct work_struct *work)
631
struct afs_cache_vlocation vldb;
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struct afs_vlocation *vl, *xvl;
641
/* find a record to update */
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spin_lock(&afs_vlocation_updates_lock);
644
if (list_empty(&afs_vlocation_updates)) {
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spin_unlock(&afs_vlocation_updates_lock);
646
_leave(" [nothing]");
650
vl = list_entry(afs_vlocation_updates.next,
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struct afs_vlocation, update);
652
if (atomic_read(&vl->usage) > 0)
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list_del_init(&vl->update);
657
timeout = vl->update_at - now;
659
queue_delayed_work(afs_vlocation_update_worker,
660
&afs_vlocation_update, timeout * HZ);
661
spin_unlock(&afs_vlocation_updates_lock);
662
_leave(" [nothing]");
666
list_del_init(&vl->update);
667
atomic_inc(&vl->usage);
668
spin_unlock(&afs_vlocation_updates_lock);
670
/* we can now perform the update */
671
_debug("update %s", vl->vldb.name);
672
vl->state = AFS_VL_UPDATING;
674
vl->upd_busy_cnt = 0;
676
ret = afs_vlocation_update_record(vl, NULL, &vldb);
677
spin_lock(&vl->lock);
680
afs_vlocation_apply_update(vl, &vldb);
681
vl->state = AFS_VL_VALID;
684
vl->state = AFS_VL_VOLUME_DELETED;
687
vl->state = AFS_VL_UNCERTAIN;
690
spin_unlock(&vl->lock);
693
/* and then reschedule */
694
_debug("reschedule");
695
vl->update_at = get_seconds() + afs_vlocation_update_timeout;
697
spin_lock(&afs_vlocation_updates_lock);
699
if (!list_empty(&afs_vlocation_updates)) {
700
/* next update in 10 minutes, but wait at least 1 second more
701
* than the newest record already queued so that we don't spam
702
* the VL server suddenly with lots of requests
704
xvl = list_entry(afs_vlocation_updates.prev,
705
struct afs_vlocation, update);
706
if (vl->update_at <= xvl->update_at)
707
vl->update_at = xvl->update_at + 1;
708
xvl = list_entry(afs_vlocation_updates.next,
709
struct afs_vlocation, update);
710
timeout = xvl->update_at - now;
714
timeout = afs_vlocation_update_timeout;
717
ASSERT(list_empty(&vl->update));
719
list_add_tail(&vl->update, &afs_vlocation_updates);
721
_debug("timeout %ld", timeout);
722
queue_delayed_work(afs_vlocation_update_worker,
723
&afs_vlocation_update, timeout * HZ);
724
spin_unlock(&afs_vlocation_updates_lock);
725
afs_put_vlocation(vl);