From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- fs/afs/rotate.c | 518 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 518 insertions(+) create mode 100644 fs/afs/rotate.c (limited to 'fs/afs/rotate.c') diff --git a/fs/afs/rotate.c b/fs/afs/rotate.c new file mode 100644 index 000000000..a840c3588 --- /dev/null +++ b/fs/afs/rotate.c @@ -0,0 +1,518 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Handle fileserver selection and rotation. + * + * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include +#include +#include +#include +#include +#include +#include "internal.h" +#include "afs_fs.h" + +/* + * Begin iteration through a server list, starting with the vnode's last used + * server if possible, or the last recorded good server if not. + */ +static bool afs_start_fs_iteration(struct afs_operation *op, + struct afs_vnode *vnode) +{ + struct afs_server *server; + void *cb_server; + int i; + + read_lock(&op->volume->servers_lock); + op->server_list = afs_get_serverlist( + rcu_dereference_protected(op->volume->servers, + lockdep_is_held(&op->volume->servers_lock))); + read_unlock(&op->volume->servers_lock); + + op->untried = (1UL << op->server_list->nr_servers) - 1; + op->index = READ_ONCE(op->server_list->preferred); + + cb_server = vnode->cb_server; + if (cb_server) { + /* See if the vnode's preferred record is still available */ + for (i = 0; i < op->server_list->nr_servers; i++) { + server = op->server_list->servers[i].server; + if (server == cb_server) { + op->index = i; + goto found_interest; + } + } + + /* If we have a lock outstanding on a server that's no longer + * serving this vnode, then we can't switch to another server + * and have to return an error. + */ + if (op->flags & AFS_OPERATION_CUR_ONLY) { + op->error = -ESTALE; + return false; + } + + /* Note that the callback promise is effectively broken */ + write_seqlock(&vnode->cb_lock); + ASSERTCMP(cb_server, ==, vnode->cb_server); + vnode->cb_server = NULL; + if (test_and_clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) + vnode->cb_break++; + write_sequnlock(&vnode->cb_lock); + } + +found_interest: + return true; +} + +/* + * Post volume busy note. + */ +static void afs_busy(struct afs_volume *volume, u32 abort_code) +{ + const char *m; + + switch (abort_code) { + case VOFFLINE: m = "offline"; break; + case VRESTARTING: m = "restarting"; break; + case VSALVAGING: m = "being salvaged"; break; + default: m = "busy"; break; + } + + pr_notice("kAFS: Volume %llu '%s' is %s\n", volume->vid, volume->name, m); +} + +/* + * Sleep and retry the operation to the same fileserver. + */ +static bool afs_sleep_and_retry(struct afs_operation *op) +{ + if (!(op->flags & AFS_OPERATION_UNINTR)) { + msleep_interruptible(1000); + if (signal_pending(current)) { + op->error = -ERESTARTSYS; + return false; + } + } else { + msleep(1000); + } + + return true; +} + +/* + * Select the fileserver to use. May be called multiple times to rotate + * through the fileservers. + */ +bool afs_select_fileserver(struct afs_operation *op) +{ + struct afs_addr_list *alist; + struct afs_server *server; + struct afs_vnode *vnode = op->file[0].vnode; + struct afs_error e; + u32 rtt; + int error = op->ac.error, i; + + _enter("%lx[%d],%lx[%d],%d,%d", + op->untried, op->index, + op->ac.tried, op->ac.index, + error, op->ac.abort_code); + + if (op->flags & AFS_OPERATION_STOP) { + _leave(" = f [stopped]"); + return false; + } + + op->nr_iterations++; + + /* Evaluate the result of the previous operation, if there was one. */ + switch (error) { + case SHRT_MAX: + goto start; + + case 0: + default: + /* Success or local failure. Stop. */ + op->error = error; + op->flags |= AFS_OPERATION_STOP; + _leave(" = f [okay/local %d]", error); + return false; + + case -ECONNABORTED: + /* The far side rejected the operation on some grounds. This + * might involve the server being busy or the volume having been moved. + */ + switch (op->ac.abort_code) { + case VNOVOL: + /* This fileserver doesn't know about the volume. + * - May indicate that the VL is wrong - retry once and compare + * the results. + * - May indicate that the fileserver couldn't attach to the vol. + */ + if (op->flags & AFS_OPERATION_VNOVOL) { + op->error = -EREMOTEIO; + goto next_server; + } + + write_lock(&op->volume->servers_lock); + op->server_list->vnovol_mask |= 1 << op->index; + write_unlock(&op->volume->servers_lock); + + set_bit(AFS_VOLUME_NEEDS_UPDATE, &op->volume->flags); + error = afs_check_volume_status(op->volume, op); + if (error < 0) + goto failed_set_error; + + if (test_bit(AFS_VOLUME_DELETED, &op->volume->flags)) { + op->error = -ENOMEDIUM; + goto failed; + } + + /* If the server list didn't change, then assume that + * it's the fileserver having trouble. + */ + if (rcu_access_pointer(op->volume->servers) == op->server_list) { + op->error = -EREMOTEIO; + goto next_server; + } + + /* Try again */ + op->flags |= AFS_OPERATION_VNOVOL; + _leave(" = t [vnovol]"); + return true; + + case VSALVAGE: /* TODO: Should this return an error or iterate? */ + case VVOLEXISTS: + case VNOSERVICE: + case VONLINE: + case VDISKFULL: + case VOVERQUOTA: + op->error = afs_abort_to_error(op->ac.abort_code); + goto next_server; + + case VOFFLINE: + if (!test_and_set_bit(AFS_VOLUME_OFFLINE, &op->volume->flags)) { + afs_busy(op->volume, op->ac.abort_code); + clear_bit(AFS_VOLUME_BUSY, &op->volume->flags); + } + if (op->flags & AFS_OPERATION_NO_VSLEEP) { + op->error = -EADV; + goto failed; + } + if (op->flags & AFS_OPERATION_CUR_ONLY) { + op->error = -ESTALE; + goto failed; + } + goto busy; + + case VSALVAGING: + case VRESTARTING: + case VBUSY: + /* Retry after going round all the servers unless we + * have a file lock we need to maintain. + */ + if (op->flags & AFS_OPERATION_NO_VSLEEP) { + op->error = -EBUSY; + goto failed; + } + if (!test_and_set_bit(AFS_VOLUME_BUSY, &op->volume->flags)) { + afs_busy(op->volume, op->ac.abort_code); + clear_bit(AFS_VOLUME_OFFLINE, &op->volume->flags); + } + busy: + if (op->flags & AFS_OPERATION_CUR_ONLY) { + if (!afs_sleep_and_retry(op)) + goto failed; + + /* Retry with same server & address */ + _leave(" = t [vbusy]"); + return true; + } + + op->flags |= AFS_OPERATION_VBUSY; + goto next_server; + + case VMOVED: + /* The volume migrated to another server. We consider + * consider all locks and callbacks broken and request + * an update from the VLDB. + * + * We also limit the number of VMOVED hops we will + * honour, just in case someone sets up a loop. + */ + if (op->flags & AFS_OPERATION_VMOVED) { + op->error = -EREMOTEIO; + goto failed; + } + op->flags |= AFS_OPERATION_VMOVED; + + set_bit(AFS_VOLUME_WAIT, &op->volume->flags); + set_bit(AFS_VOLUME_NEEDS_UPDATE, &op->volume->flags); + error = afs_check_volume_status(op->volume, op); + if (error < 0) + goto failed_set_error; + + /* If the server list didn't change, then the VLDB is + * out of sync with the fileservers. This is hopefully + * a temporary condition, however, so we don't want to + * permanently block access to the file. + * + * TODO: Try other fileservers if we can. + * + * TODO: Retry a few times with sleeps. + */ + if (rcu_access_pointer(op->volume->servers) == op->server_list) { + op->error = -ENOMEDIUM; + goto failed; + } + + goto restart_from_beginning; + + default: + clear_bit(AFS_VOLUME_OFFLINE, &op->volume->flags); + clear_bit(AFS_VOLUME_BUSY, &op->volume->flags); + op->error = afs_abort_to_error(op->ac.abort_code); + goto failed; + } + + case -ETIMEDOUT: + case -ETIME: + if (op->error != -EDESTADDRREQ) + goto iterate_address; + fallthrough; + case -ERFKILL: + case -EADDRNOTAVAIL: + case -ENETUNREACH: + case -EHOSTUNREACH: + case -EHOSTDOWN: + case -ECONNREFUSED: + _debug("no conn"); + op->error = error; + goto iterate_address; + + case -ENETRESET: + pr_warn("kAFS: Peer reset %s (op=%x)\n", + op->type ? op->type->name : "???", op->debug_id); + fallthrough; + case -ECONNRESET: + _debug("call reset"); + op->error = error; + goto failed; + } + +restart_from_beginning: + _debug("restart"); + afs_end_cursor(&op->ac); + op->server = NULL; + afs_put_serverlist(op->net, op->server_list); + op->server_list = NULL; +start: + _debug("start"); + /* See if we need to do an update of the volume record. Note that the + * volume may have moved or even have been deleted. + */ + error = afs_check_volume_status(op->volume, op); + if (error < 0) + goto failed_set_error; + + if (!afs_start_fs_iteration(op, vnode)) + goto failed; + + _debug("__ VOL %llx __", op->volume->vid); + +pick_server: + _debug("pick [%lx]", op->untried); + + error = afs_wait_for_fs_probes(op->server_list, op->untried); + if (error < 0) + goto failed_set_error; + + /* Pick the untried server with the lowest RTT. If we have outstanding + * callbacks, we stick with the server we're already using if we can. + */ + if (op->server) { + _debug("server %u", op->index); + if (test_bit(op->index, &op->untried)) + goto selected_server; + op->server = NULL; + _debug("no server"); + } + + op->index = -1; + rtt = U32_MAX; + for (i = 0; i < op->server_list->nr_servers; i++) { + struct afs_server *s = op->server_list->servers[i].server; + + if (!test_bit(i, &op->untried) || + !test_bit(AFS_SERVER_FL_RESPONDING, &s->flags)) + continue; + if (s->probe.rtt < rtt) { + op->index = i; + rtt = s->probe.rtt; + } + } + + if (op->index == -1) + goto no_more_servers; + +selected_server: + _debug("use %d", op->index); + __clear_bit(op->index, &op->untried); + + /* We're starting on a different fileserver from the list. We need to + * check it, create a callback intercept, find its address list and + * probe its capabilities before we use it. + */ + ASSERTCMP(op->ac.alist, ==, NULL); + server = op->server_list->servers[op->index].server; + + if (!afs_check_server_record(op, server)) + goto failed; + + _debug("USING SERVER: %pU", &server->uuid); + + op->flags |= AFS_OPERATION_RETRY_SERVER; + op->server = server; + if (vnode->cb_server != server) { + vnode->cb_server = server; + vnode->cb_s_break = server->cb_s_break; + vnode->cb_fs_s_break = atomic_read(&server->cell->fs_s_break); + vnode->cb_v_break = vnode->volume->cb_v_break; + clear_bit(AFS_VNODE_CB_PROMISED, &vnode->flags); + } + + read_lock(&server->fs_lock); + alist = rcu_dereference_protected(server->addresses, + lockdep_is_held(&server->fs_lock)); + afs_get_addrlist(alist); + read_unlock(&server->fs_lock); + +retry_server: + memset(&op->ac, 0, sizeof(op->ac)); + + if (!op->ac.alist) + op->ac.alist = alist; + else + afs_put_addrlist(alist); + + op->ac.index = -1; + +iterate_address: + ASSERT(op->ac.alist); + /* Iterate over the current server's address list to try and find an + * address on which it will respond to us. + */ + if (!afs_iterate_addresses(&op->ac)) + goto out_of_addresses; + + _debug("address [%u] %u/%u %pISp", + op->index, op->ac.index, op->ac.alist->nr_addrs, + &op->ac.alist->addrs[op->ac.index].transport); + + _leave(" = t"); + return true; + +out_of_addresses: + /* We've now had a failure to respond on all of a server's addresses - + * immediately probe them again and consider retrying the server. + */ + afs_probe_fileserver(op->net, op->server); + if (op->flags & AFS_OPERATION_RETRY_SERVER) { + alist = op->ac.alist; + error = afs_wait_for_one_fs_probe( + op->server, !(op->flags & AFS_OPERATION_UNINTR)); + switch (error) { + case 0: + op->flags &= ~AFS_OPERATION_RETRY_SERVER; + goto retry_server; + case -ERESTARTSYS: + goto failed_set_error; + case -ETIME: + case -EDESTADDRREQ: + goto next_server; + } + } + +next_server: + _debug("next"); + afs_end_cursor(&op->ac); + goto pick_server; + +no_more_servers: + /* That's all the servers poked to no good effect. Try again if some + * of them were busy. + */ + if (op->flags & AFS_OPERATION_VBUSY) + goto restart_from_beginning; + + e.error = -EDESTADDRREQ; + e.responded = false; + for (i = 0; i < op->server_list->nr_servers; i++) { + struct afs_server *s = op->server_list->servers[i].server; + + afs_prioritise_error(&e, READ_ONCE(s->probe.error), + s->probe.abort_code); + } + + error = e.error; + +failed_set_error: + op->error = error; +failed: + op->flags |= AFS_OPERATION_STOP; + afs_end_cursor(&op->ac); + _leave(" = f [failed %d]", op->error); + return false; +} + +/* + * Dump cursor state in the case of the error being EDESTADDRREQ. + */ +void afs_dump_edestaddrreq(const struct afs_operation *op) +{ + static int count; + int i; + + if (!IS_ENABLED(CONFIG_AFS_DEBUG_CURSOR) || count > 3) + return; + count++; + + rcu_read_lock(); + + pr_notice("EDESTADDR occurred\n"); + pr_notice("FC: cbb=%x cbb2=%x fl=%x err=%hd\n", + op->file[0].cb_break_before, + op->file[1].cb_break_before, op->flags, op->error); + pr_notice("FC: ut=%lx ix=%d ni=%u\n", + op->untried, op->index, op->nr_iterations); + + if (op->server_list) { + const struct afs_server_list *sl = op->server_list; + pr_notice("FC: SL nr=%u pr=%u vnov=%hx\n", + sl->nr_servers, sl->preferred, sl->vnovol_mask); + for (i = 0; i < sl->nr_servers; i++) { + const struct afs_server *s = sl->servers[i].server; + pr_notice("FC: server fl=%lx av=%u %pU\n", + s->flags, s->addr_version, &s->uuid); + if (s->addresses) { + const struct afs_addr_list *a = + rcu_dereference(s->addresses); + pr_notice("FC: - av=%u nr=%u/%u/%u pr=%u\n", + a->version, + a->nr_ipv4, a->nr_addrs, a->max_addrs, + a->preferred); + pr_notice("FC: - R=%lx F=%lx\n", + a->responded, a->failed); + if (a == op->ac.alist) + pr_notice("FC: - current\n"); + } + } + } + + pr_notice("AC: t=%lx ax=%u ac=%d er=%d r=%u ni=%u\n", + op->ac.tried, op->ac.index, op->ac.abort_code, op->ac.error, + op->ac.responded, op->ac.nr_iterations); + rcu_read_unlock(); +} -- cgit v1.2.3