--- /dev/null
+/* Handle fileserver selection and rotation.
+ *
+ * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+/*
+ * Initialise a filesystem server cursor for iterating over FS servers.
+ */
+void afs_init_fs_cursor(struct afs_fs_cursor *fc, struct afs_vnode *vnode)
+{
+ memset(fc, 0, sizeof(*fc));
+}
+
+/*
+ * Set a filesystem server cursor for using a specific FS server.
+ */
+int afs_set_fs_cursor(struct afs_fs_cursor *fc, struct afs_vnode *vnode)
+{
+ afs_init_fs_cursor(fc, vnode);
+
+ read_seqlock_excl(&vnode->cb_lock);
+ if (vnode->cb_interest) {
+ if (vnode->cb_interest->server->fs_state == 0)
+ fc->server = afs_get_server(vnode->cb_interest->server);
+ else
+ fc->ac.error = vnode->cb_interest->server->fs_state;
+ } else {
+ fc->ac.error = -ESTALE;
+ }
+ read_sequnlock_excl(&vnode->cb_lock);
+
+ return fc->ac.error;
+}
+
+/*
+ * pick a server to use to try accessing this volume
+ * - returns with an elevated usage count on the server chosen
+ */
+bool afs_volume_pick_fileserver(struct afs_fs_cursor *fc, struct afs_vnode *vnode)
+{
+ struct afs_volume *volume = vnode->volume;
+ struct afs_server *server;
+ int ret, state, loop;
+
+ _enter("%s", volume->vlocation->vldb.name);
+
+ /* stick with the server we're already using if we can */
+ if (vnode->cb_interest && vnode->cb_interest->server->fs_state == 0) {
+ fc->server = afs_get_server(vnode->cb_interest->server);
+ goto set_server;
+ }
+
+ down_read(&volume->server_sem);
+
+ /* handle the no-server case */
+ if (volume->nservers == 0) {
+ fc->ac.error = volume->rjservers ? -ENOMEDIUM : -ESTALE;
+ up_read(&volume->server_sem);
+ _leave(" = f [no servers %d]", fc->ac.error);
+ return false;
+ }
+
+ /* basically, just search the list for the first live server and use
+ * that */
+ ret = 0;
+ for (loop = 0; loop < volume->nservers; loop++) {
+ server = volume->servers[loop];
+ state = server->fs_state;
+
+ _debug("consider %d [%d]", loop, state);
+
+ switch (state) {
+ case 0:
+ goto picked_server;
+
+ case -ENETUNREACH:
+ if (ret == 0)
+ ret = state;
+ break;
+
+ case -EHOSTUNREACH:
+ if (ret == 0 ||
+ ret == -ENETUNREACH)
+ ret = state;
+ break;
+
+ case -ECONNREFUSED:
+ if (ret == 0 ||
+ ret == -ENETUNREACH ||
+ ret == -EHOSTUNREACH)
+ ret = state;
+ break;
+
+ default:
+ case -EREMOTEIO:
+ if (ret == 0 ||
+ ret == -ENETUNREACH ||
+ ret == -EHOSTUNREACH ||
+ ret == -ECONNREFUSED)
+ ret = state;
+ break;
+ }
+ }
+
+error:
+ fc->ac.error = ret;
+
+ /* no available servers
+ * - TODO: handle the no active servers case better
+ */
+ up_read(&volume->server_sem);
+ _leave(" = f [%d]", fc->ac.error);
+ return false;
+
+picked_server:
+ /* Found an apparently healthy server. We need to register an interest
+ * in receiving callbacks before we talk to it.
+ */
+ ret = afs_register_server_cb_interest(vnode,
+ &volume->cb_interests[loop], server);
+ if (ret < 0)
+ goto error;
+
+ fc->server = afs_get_server(server);
+ up_read(&volume->server_sem);
+set_server:
+ fc->ac.alist = afs_get_addrlist(fc->server->addrs);
+ fc->ac.addr = &fc->ac.alist->addrs[0];
+ _debug("USING SERVER: %pIS\n", &fc->ac.addr->transport);
+ _leave(" = t (picked %pIS)", &fc->ac.addr->transport);
+ return true;
+}
+
+/*
+ * release a server after use
+ * - releases the ref on the server struct that was acquired by picking
+ * - records result of using a particular server to access a volume
+ * - return true to try again, false if okay or to issue error
+ * - the caller must release the server struct if result was false
+ */
+bool afs_iterate_fs_cursor(struct afs_fs_cursor *fc,
+ struct afs_vnode *vnode)
+{
+ struct afs_volume *volume = vnode->volume;
+ struct afs_server *server = fc->server;
+ unsigned loop;
+
+ _enter("%s,%pIS,%d",
+ volume->vlocation->vldb.name, &fc->ac.addr->transport,
+ fc->ac.error);
+
+ switch (fc->ac.error) {
+ /* success */
+ case 0:
+ server->fs_state = 0;
+ _leave(" = f");
+ return false;
+
+ /* the fileserver denied all knowledge of the volume */
+ case -ENOMEDIUM:
+ down_write(&volume->server_sem);
+
+ /* firstly, find where the server is in the active list (if it
+ * is) */
+ for (loop = 0; loop < volume->nservers; loop++)
+ if (volume->servers[loop] == server)
+ goto present;
+
+ /* no longer there - may have been discarded by another op */
+ goto try_next_server_upw;
+
+ present:
+ volume->nservers--;
+ memmove(&volume->servers[loop],
+ &volume->servers[loop + 1],
+ sizeof(volume->servers[loop]) *
+ (volume->nservers - loop));
+ volume->servers[volume->nservers] = NULL;
+ afs_put_server(afs_v2net(vnode), server);
+ volume->rjservers++;
+
+ if (volume->nservers > 0)
+ /* another server might acknowledge its existence */
+ goto try_next_server_upw;
+
+ /* handle the case where all the fileservers have rejected the
+ * volume
+ * - TODO: try asking the fileservers for volume information
+ * - TODO: contact the VL server again to see if the volume is
+ * no longer registered
+ */
+ up_write(&volume->server_sem);
+ afs_put_server(afs_v2net(vnode), server);
+ fc->server = NULL;
+ _leave(" = f [completely rejected]");
+ return false;
+
+ /* problem reaching the server */
+ case -ENETUNREACH:
+ case -EHOSTUNREACH:
+ case -ECONNREFUSED:
+ case -ETIME:
+ case -ETIMEDOUT:
+ case -EREMOTEIO:
+ /* mark the server as dead
+ * TODO: vary dead timeout depending on error
+ */
+ spin_lock(&server->fs_lock);
+ if (!server->fs_state) {
+ server->fs_state = fc->ac.error;
+ printk("kAFS: SERVER DEAD state=%d\n", fc->ac.error);
+ }
+ spin_unlock(&server->fs_lock);
+ goto try_next_server;
+
+ /* miscellaneous error */
+ default:
+ case -ENOMEM:
+ case -ENONET:
+ /* tell the caller to accept the result */
+ afs_put_server(afs_v2net(vnode), server);
+ fc->server = NULL;
+ _leave(" = f [local failure]");
+ return false;
+ }
+
+ /* tell the caller to loop around and try the next server */
+try_next_server_upw:
+ up_write(&volume->server_sem);
+try_next_server:
+ afs_put_server(afs_v2net(vnode), server);
+ _leave(" = t [try next server]");
+ return true;
+}
+
+/*
+ * Clean up a fileserver cursor.
+ */
+int afs_end_fs_cursor(struct afs_fs_cursor *fc, struct afs_net *net)
+{
+ afs_end_cursor(&fc->ac);
+ afs_put_server(net, fc->server);
+ return fc->ac.error;
+}
*/
#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/init.h>
#include <linux/slab.h>
-#include <linux/fs.h>
-#include <linux/pagemap.h>
-#include <linux/sched.h>
#include "internal.h"
static const char *afs_voltypes[] = { "R/W", "R/O", "BAK" };
_leave(" [destroyed]");
}
-
-/*
- * Initialise a filesystem server cursor for iterating over FS servers.
- */
-void afs_init_fs_cursor(struct afs_fs_cursor *fc, struct afs_vnode *vnode)
-{
- fc->ac.alist = NULL;
- fc->ac.addr = NULL;
- fc->ac.start = 0;
- fc->ac.index = 0;
- fc->ac.error = 0;
- fc->server = NULL;
-}
-
-/*
- * Set a filesystem server cursor for using a specific FS server.
- */
-int afs_set_fs_cursor(struct afs_fs_cursor *fc, struct afs_vnode *vnode)
-{
- afs_init_fs_cursor(fc, vnode);
-
- read_seqlock_excl(&vnode->cb_lock);
- if (vnode->cb_interest) {
- if (vnode->cb_interest->server->fs_state == 0)
- fc->server = afs_get_server(vnode->cb_interest->server);
- else
- fc->ac.error = vnode->cb_interest->server->fs_state;
- } else {
- fc->ac.error = -ESTALE;
- }
- read_sequnlock_excl(&vnode->cb_lock);
-
- return fc->ac.error;
-}
-
-/*
- * pick a server to use to try accessing this volume
- * - returns with an elevated usage count on the server chosen
- */
-bool afs_volume_pick_fileserver(struct afs_fs_cursor *fc, struct afs_vnode *vnode)
-{
- struct afs_volume *volume = vnode->volume;
- struct afs_server *server;
- int ret, state, loop;
-
- _enter("%s", volume->vlocation->vldb.name);
-
- /* stick with the server we're already using if we can */
- if (vnode->cb_interest && vnode->cb_interest->server->fs_state == 0) {
- fc->server = afs_get_server(vnode->cb_interest->server);
- goto set_server;
- }
-
- down_read(&volume->server_sem);
-
- /* handle the no-server case */
- if (volume->nservers == 0) {
- fc->ac.error = volume->rjservers ? -ENOMEDIUM : -ESTALE;
- up_read(&volume->server_sem);
- _leave(" = f [no servers %d]", fc->ac.error);
- return false;
- }
-
- /* basically, just search the list for the first live server and use
- * that */
- ret = 0;
- for (loop = 0; loop < volume->nservers; loop++) {
- server = volume->servers[loop];
- state = server->fs_state;
-
- _debug("consider %d [%d]", loop, state);
-
- switch (state) {
- case 0:
- goto picked_server;
-
- case -ENETUNREACH:
- if (ret == 0)
- ret = state;
- break;
-
- case -EHOSTUNREACH:
- if (ret == 0 ||
- ret == -ENETUNREACH)
- ret = state;
- break;
-
- case -ECONNREFUSED:
- if (ret == 0 ||
- ret == -ENETUNREACH ||
- ret == -EHOSTUNREACH)
- ret = state;
- break;
-
- default:
- case -EREMOTEIO:
- if (ret == 0 ||
- ret == -ENETUNREACH ||
- ret == -EHOSTUNREACH ||
- ret == -ECONNREFUSED)
- ret = state;
- break;
- }
- }
-
-error:
- fc->ac.error = ret;
-
- /* no available servers
- * - TODO: handle the no active servers case better
- */
- up_read(&volume->server_sem);
- _leave(" = f [%d]", fc->ac.error);
- return false;
-
-picked_server:
- /* Found an apparently healthy server. We need to register an interest
- * in receiving callbacks before we talk to it.
- */
- ret = afs_register_server_cb_interest(vnode,
- &volume->cb_interests[loop], server);
- if (ret < 0)
- goto error;
-
- fc->server = afs_get_server(server);
- up_read(&volume->server_sem);
-set_server:
- fc->ac.alist = afs_get_addrlist(fc->server->addrs);
- fc->ac.addr = &fc->ac.alist->addrs[0];
- _debug("USING SERVER: %pIS\n", &fc->ac.addr->transport);
- _leave(" = t (picked %pIS)", &fc->ac.addr->transport);
- return true;
-}
-
-/*
- * release a server after use
- * - releases the ref on the server struct that was acquired by picking
- * - records result of using a particular server to access a volume
- * - return true to try again, false if okay or to issue error
- * - the caller must release the server struct if result was false
- */
-bool afs_iterate_fs_cursor(struct afs_fs_cursor *fc,
- struct afs_vnode *vnode)
-{
- struct afs_volume *volume = vnode->volume;
- struct afs_server *server = fc->server;
- unsigned loop;
-
- _enter("%s,%pIS,%d",
- volume->vlocation->vldb.name, &fc->ac.addr->transport,
- fc->ac.error);
-
- switch (fc->ac.error) {
- /* success */
- case 0:
- server->fs_state = 0;
- _leave(" = f");
- return false;
-
- /* the fileserver denied all knowledge of the volume */
- case -ENOMEDIUM:
- down_write(&volume->server_sem);
-
- /* firstly, find where the server is in the active list (if it
- * is) */
- for (loop = 0; loop < volume->nservers; loop++)
- if (volume->servers[loop] == server)
- goto present;
-
- /* no longer there - may have been discarded by another op */
- goto try_next_server_upw;
-
- present:
- volume->nservers--;
- memmove(&volume->servers[loop],
- &volume->servers[loop + 1],
- sizeof(volume->servers[loop]) *
- (volume->nservers - loop));
- volume->servers[volume->nservers] = NULL;
- afs_put_server(afs_v2net(vnode), server);
- volume->rjservers++;
-
- if (volume->nservers > 0)
- /* another server might acknowledge its existence */
- goto try_next_server_upw;
-
- /* handle the case where all the fileservers have rejected the
- * volume
- * - TODO: try asking the fileservers for volume information
- * - TODO: contact the VL server again to see if the volume is
- * no longer registered
- */
- up_write(&volume->server_sem);
- afs_put_server(afs_v2net(vnode), server);
- fc->server = NULL;
- _leave(" = f [completely rejected]");
- return false;
-
- /* problem reaching the server */
- case -ENETUNREACH:
- case -EHOSTUNREACH:
- case -ECONNREFUSED:
- case -ETIME:
- case -ETIMEDOUT:
- case -EREMOTEIO:
- /* mark the server as dead
- * TODO: vary dead timeout depending on error
- */
- spin_lock(&server->fs_lock);
- if (!server->fs_state) {
- server->fs_state = fc->ac.error;
- printk("kAFS: SERVER DEAD state=%d\n", fc->ac.error);
- }
- spin_unlock(&server->fs_lock);
- goto try_next_server;
-
- /* miscellaneous error */
- default:
- case -ENOMEM:
- case -ENONET:
- /* tell the caller to accept the result */
- afs_put_server(afs_v2net(vnode), server);
- fc->server = NULL;
- _leave(" = f [local failure]");
- return false;
- }
-
- /* tell the caller to loop around and try the next server */
-try_next_server_upw:
- up_write(&volume->server_sem);
-try_next_server:
- afs_put_server(afs_v2net(vnode), server);
- _leave(" = t [try next server]");
- return true;
-}
-
-/*
- * Clean up a fileserver cursor.
- */
-int afs_end_fs_cursor(struct afs_fs_cursor *fc, struct afs_net *net)
-{
- afs_end_cursor(&fc->ac);
- afs_put_server(net, fc->server);
- return fc->ac.error;
-}
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