diff options
Diffstat (limited to 'fs/afs')
| -rw-r--r-- | fs/afs/Makefile | 1 | ||||
| -rw-r--r-- | fs/afs/cell.c | 3 | ||||
| -rw-r--r-- | fs/afs/internal.h | 17 | ||||
| -rw-r--r-- | fs/afs/main.c | 1 | ||||
| -rw-r--r-- | fs/afs/proc.c | 5 | ||||
| -rw-r--r-- | fs/afs/rotate.c | 8 | ||||
| -rw-r--r-- | fs/afs/super.c | 21 | ||||
| -rw-r--r-- | fs/afs/vl_alias.c | 235 | ||||
| -rw-r--r-- | fs/afs/volume.c | 9 |
9 files changed, 287 insertions, 13 deletions
diff --git a/fs/afs/Makefile b/fs/afs/Makefile index 924f02e9d7e7..75c4e4043d1d 100644 --- a/fs/afs/Makefile +++ b/fs/afs/Makefile @@ -31,6 +31,7 @@ kafs-y := \ server_list.o \ super.o \ vlclient.o \ + vl_alias.o \ vl_list.o \ vl_probe.o \ vl_rotate.o \ diff --git a/fs/afs/cell.c b/fs/afs/cell.c index 78ba5f932287..212098514ebf 100644 --- a/fs/afs/cell.c +++ b/fs/afs/cell.c @@ -164,6 +164,7 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net, INIT_LIST_HEAD(&cell->proc_volumes); rwlock_init(&cell->proc_lock); rwlock_init(&cell->vl_servers_lock); + cell->flags = (1 << AFS_CELL_FL_CHECK_ALIAS); /* Provide a VL server list, filling it in if we were given a list of * addresses to use. @@ -481,7 +482,9 @@ static void afs_cell_destroy(struct rcu_head *rcu) ASSERTCMP(atomic_read(&cell->usage), ==, 0); + afs_put_volume(cell->net, cell->root_volume); afs_put_vlserverlist(cell->net, rcu_access_pointer(cell->vl_servers)); + afs_put_cell(cell->net, cell->alias_of); key_put(cell->anonymous_key); kfree(cell); diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 3606cfa50832..a3ef97d560ca 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -269,6 +269,7 @@ struct afs_net { struct timer_list cells_timer; atomic_t cells_outstanding; seqlock_t cells_lock; + struct mutex cells_alias_lock; struct mutex proc_cells_lock; struct hlist_head proc_cells; @@ -342,8 +343,10 @@ enum afs_cell_state { * for authentication and encryption. The cell name is not typically used in * the protocol. * - * There is no easy way to determine if two cells are aliases or one is a - * subset of another. + * Two cells are determined to be aliases if they have an explicit alias (YFS + * only), share any VL servers in common or have at least one volume in common. + * "In common" means that the address list of the VL servers or the fileservers + * share at least one endpoint. */ struct afs_cell { union { @@ -351,6 +354,8 @@ struct afs_cell { struct rb_node net_node; /* Node in net->cells */ }; struct afs_net *net; + struct afs_cell *alias_of; /* The cell this is an alias of */ + struct afs_volume *root_volume; /* The root.cell volume if there is one */ struct key *anonymous_key; /* anonymous user key for this cell */ struct work_struct manager; /* Manager for init/deinit/dns */ struct hlist_node proc_link; /* /proc cell list link */ @@ -363,6 +368,7 @@ struct afs_cell { unsigned long flags; #define AFS_CELL_FL_NO_GC 0 /* The cell was added manually, don't auto-gc */ #define AFS_CELL_FL_DO_LOOKUP 1 /* DNS lookup requested */ +#define AFS_CELL_FL_CHECK_ALIAS 2 /* Need to check for aliases */ enum afs_cell_state state; short error; enum dns_record_source dns_source:8; /* Latest source of data from lookup */ @@ -584,7 +590,7 @@ struct afs_volume { #ifdef CONFIG_AFS_FSCACHE struct fscache_cookie *cache; /* caching cookie */ #endif - struct afs_server_list *servers; /* List of servers on which volume resides */ + struct afs_server_list __rcu *servers; /* List of servers on which volume resides */ rwlock_t servers_lock; /* Lock for ->servers */ unsigned int servers_seq; /* Incremented each time ->servers changes */ @@ -1377,6 +1383,11 @@ extern struct afs_addr_list *afs_yfsvl_get_endpoints(struct afs_vl_cursor *, con extern char *afs_yfsvl_get_cell_name(struct afs_vl_cursor *); /* + * vl_alias.c + */ +extern int afs_cell_detect_alias(struct afs_cell *, struct key *); + +/* * vl_probe.c */ extern void afs_vlserver_probe_result(struct afs_call *); diff --git a/fs/afs/main.c b/fs/afs/main.c index 56b52f8dbf15..9c79c91e8005 100644 --- a/fs/afs/main.c +++ b/fs/afs/main.c @@ -82,6 +82,7 @@ static int __net_init afs_net_init(struct net *net_ns) INIT_WORK(&net->cells_manager, afs_manage_cells); timer_setup(&net->cells_timer, afs_cells_timer, 0); + mutex_init(&net->cells_alias_lock); mutex_init(&net->proc_cells_lock); INIT_HLIST_HEAD(&net->proc_cells); diff --git a/fs/afs/proc.c b/fs/afs/proc.c index 1d21465a4108..256c3eff8c82 100644 --- a/fs/afs/proc.c +++ b/fs/afs/proc.c @@ -38,7 +38,7 @@ static int afs_proc_cells_show(struct seq_file *m, void *v) if (v == SEQ_START_TOKEN) { /* display header on line 1 */ - seq_puts(m, "USE TTL SV NAME\n"); + seq_puts(m, "USE TTL SV ST NAME\n"); return 0; } @@ -46,10 +46,11 @@ static int afs_proc_cells_show(struct seq_file *m, void *v) vllist = rcu_dereference(cell->vl_servers); /* display one cell per line on subsequent lines */ - seq_printf(m, "%3u %6lld %2u %s\n", + seq_printf(m, "%3u %6lld %2u %2u %s\n", atomic_read(&cell->usage), cell->dns_expiry - ktime_get_real_seconds(), vllist->nr_servers, + cell->state, cell->name); return 0; } diff --git a/fs/afs/rotate.c b/fs/afs/rotate.c index 8c8dc2397c5d..d67b8c7eb3b9 100644 --- a/fs/afs/rotate.c +++ b/fs/afs/rotate.c @@ -25,7 +25,9 @@ static bool afs_start_fs_iteration(struct afs_operation *op, int i; read_lock(&op->volume->servers_lock); - op->server_list = afs_get_serverlist(op->volume->servers); + 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; @@ -173,7 +175,7 @@ bool afs_select_fileserver(struct afs_operation *op) /* If the server list didn't change, then assume that * it's the fileserver having trouble. */ - if (op->volume->servers == op->server_list) { + if (rcu_access_pointer(op->volume->servers) == op->server_list) { op->error = -EREMOTEIO; goto next_server; } @@ -263,7 +265,7 @@ bool afs_select_fileserver(struct afs_operation *op) * * TODO: Retry a few times with sleeps. */ - if (op->volume->servers == op->server_list) { + if (rcu_access_pointer(op->volume->servers) == op->server_list) { op->error = -ENOMEDIUM; goto failed; } diff --git a/fs/afs/super.c b/fs/afs/super.c index c4bb314a22ae..aae6866ed209 100644 --- a/fs/afs/super.c +++ b/fs/afs/super.c @@ -352,7 +352,9 @@ static int afs_validate_fc(struct fs_context *fc) { struct afs_fs_context *ctx = fc->fs_private; struct afs_volume *volume; + struct afs_cell *cell; struct key *key; + int ret; if (!ctx->dyn_root) { if (ctx->no_cell) { @@ -365,6 +367,7 @@ static int afs_validate_fc(struct fs_context *fc) return -EDESTADDRREQ; } + reget_key: /* We try to do the mount securely. */ key = afs_request_key(ctx->cell); if (IS_ERR(key)) @@ -377,6 +380,21 @@ static int afs_validate_fc(struct fs_context *fc) ctx->volume = NULL; } + if (test_bit(AFS_CELL_FL_CHECK_ALIAS, &ctx->cell->flags)) { + ret = afs_cell_detect_alias(ctx->cell, key); + if (ret < 0) + return ret; + if (ret == 1) { + _debug("switch to alias"); + key_put(ctx->key); + ctx->key = NULL; + cell = afs_get_cell(ctx->cell->alias_of); + afs_put_cell(ctx->net, ctx->cell); + ctx->cell = cell; + goto reget_key; + } + } + volume = afs_create_volume(ctx); if (IS_ERR(volume)) return PTR_ERR(volume); @@ -518,7 +536,8 @@ static void afs_kill_super(struct super_block *sb) * deactivating the superblock. */ if (as->volume) - afs_clear_callback_interests(net, as->volume->servers); + afs_clear_callback_interests( + net, rcu_access_pointer(as->volume->servers)); kill_anon_super(sb); if (as->volume) afs_deactivate_volume(as->volume); diff --git a/fs/afs/vl_alias.c b/fs/afs/vl_alias.c new file mode 100644 index 000000000000..d1d91a25fbe0 --- /dev/null +++ b/fs/afs/vl_alias.c @@ -0,0 +1,235 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* AFS cell alias detection + * + * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/slab.h> +#include <linux/sched.h> +#include <linux/namei.h> +#include <keys/rxrpc-type.h> +#include "internal.h" + +/* + * Sample a volume. + */ +static struct afs_volume *afs_sample_volume(struct afs_cell *cell, struct key *key, + const char *name, unsigned int namelen) +{ + struct afs_volume *volume; + struct afs_fs_context fc = { + .type = 0, /* Explicitly leave it to the VLDB */ + .volnamesz = namelen, + .volname = name, + .net = cell->net, + .cell = cell, + .key = key, /* This might need to be something */ + }; + + volume = afs_create_volume(&fc); + _leave(" = %px", volume); + return volume; +} + +/* + * Compare two addresses. + */ +static int afs_compare_addrs(const struct sockaddr_rxrpc *srx_a, + const struct sockaddr_rxrpc *srx_b) +{ + short port_a, port_b; + int addr_a, addr_b, diff; + + diff = (short)srx_a->transport_type - (short)srx_b->transport_type; + if (diff) + goto out; + + switch (srx_a->transport_type) { + case AF_INET: { + const struct sockaddr_in *a = &srx_a->transport.sin; + const struct sockaddr_in *b = &srx_b->transport.sin; + addr_a = ntohl(a->sin_addr.s_addr); + addr_b = ntohl(b->sin_addr.s_addr); + diff = addr_a - addr_b; + if (diff == 0) { + port_a = ntohs(a->sin_port); + port_b = ntohs(b->sin_port); + diff = port_a - port_b; + } + break; + } + + case AF_INET6: { + const struct sockaddr_in6 *a = &srx_a->transport.sin6; + const struct sockaddr_in6 *b = &srx_b->transport.sin6; + diff = memcmp(&a->sin6_addr, &b->sin6_addr, 16); + if (diff == 0) { + port_a = ntohs(a->sin6_port); + port_b = ntohs(b->sin6_port); + diff = port_a - port_b; + } + break; + } + + default: + BUG(); + } + +out: + return diff; +} + +/* + * Compare the address lists of a pair of fileservers. + */ +static int afs_compare_fs_alists(const struct afs_server *server_a, + const struct afs_server *server_b) +{ + const struct afs_addr_list *la, *lb; + int a = 0, b = 0, addr_matches = 0; + + la = rcu_dereference(server_a->addresses); + lb = rcu_dereference(server_b->addresses); + + while (a < la->nr_addrs && b < lb->nr_addrs) { + const struct sockaddr_rxrpc *srx_a = &la->addrs[a]; + const struct sockaddr_rxrpc *srx_b = &lb->addrs[b]; + int diff = afs_compare_addrs(srx_a, srx_b); + + if (diff < 0) { + a++; + } else if (diff > 0) { + b++; + } else { + addr_matches++; + a++; + b++; + } + } + + return addr_matches; +} + +/* + * Compare the fileserver lists of two volumes. The server lists are sorted in + * order of ascending UUID. + */ +static int afs_compare_volume_slists(const struct afs_volume *vol_a, + const struct afs_volume *vol_b) +{ + const struct afs_server_list *la, *lb; + int i, a = 0, b = 0, uuid_matches = 0, addr_matches = 0; + + la = rcu_dereference(vol_a->servers); + lb = rcu_dereference(vol_b->servers); + + for (i = 0; i < AFS_MAXTYPES; i++) + if (la->vids[i] != lb->vids[i]) + return 0; + + while (a < la->nr_servers && b < lb->nr_servers) { + const struct afs_server *server_a = la->servers[a].server; + const struct afs_server *server_b = lb->servers[b].server; + int diff = memcmp(&server_a->uuid, &server_b->uuid, sizeof(uuid_t)); + + if (diff < 0) { + a++; + } else if (diff > 0) { + b++; + } else { + uuid_matches++; + addr_matches += afs_compare_fs_alists(server_a, server_b); + a++; + b++; + } + } + + _leave(" = %d [um %d]", addr_matches, uuid_matches); + return addr_matches; +} + +/* + * Compare root.cell volumes. + */ +static int afs_compare_cell_roots(struct afs_cell *cell) +{ + struct afs_cell *p; + + _enter(""); + + rcu_read_lock(); + + hlist_for_each_entry_rcu(p, &cell->net->proc_cells, proc_link) { + if (p == cell || p->alias_of) + continue; + if (!p->root_volume) + continue; /* Ignore cells that don't have a root.cell volume. */ + + if (afs_compare_volume_slists(cell->root_volume, p->root_volume) != 0) + goto is_alias; + } + + rcu_read_unlock(); + _leave(" = 0"); + return 0; + +is_alias: + rcu_read_unlock(); + cell->alias_of = afs_get_cell(p); + return 1; +} + +static int afs_do_cell_detect_alias(struct afs_cell *cell, struct key *key) +{ + struct afs_volume *root_volume; + + _enter("%s", cell->name); + + /* Try and get the root.cell volume for comparison with other cells */ + root_volume = afs_sample_volume(cell, key, "root.cell", 9); + if (!IS_ERR(root_volume)) { + cell->root_volume = root_volume; + return afs_compare_cell_roots(cell); + } + + if (PTR_ERR(root_volume) != -ENOMEDIUM) + return PTR_ERR(root_volume); + + /* Okay, this cell doesn't have an root.cell volume. We need to + * locate some other random volume and use that to check. + */ + return -ENOMEDIUM; +} + +/* + * Check to see if a new cell is an alias of a cell we already have. At this + * point we have the cell's volume server list. + * + * Returns 0 if we didn't detect an alias, 1 if we found an alias and an error + * if we had problems gathering the data required. In the case the we did + * detect an alias, cell->alias_of is set to point to the assumed master. + */ +int afs_cell_detect_alias(struct afs_cell *cell, struct key *key) +{ + struct afs_net *net = cell->net; + int ret; + + if (mutex_lock_interruptible(&net->cells_alias_lock) < 0) + return -ERESTARTSYS; + + if (test_bit(AFS_CELL_FL_CHECK_ALIAS, &cell->flags)) { + ret = afs_do_cell_detect_alias(cell, key); + if (ret >= 0) + clear_bit_unlock(AFS_CELL_FL_CHECK_ALIAS, &cell->flags); + } else { + ret = cell->alias_of ? 1 : 0; + } + + mutex_unlock(&net->cells_alias_lock); + + if (ret == 1) + pr_notice("kAFS: Cell %s is an alias of %s\n", + cell->name, cell->alias_of->name); + return ret; +} diff --git a/fs/afs/volume.c b/fs/afs/volume.c index 57d0509f7353..d4d9a8fbba3d 100644 --- a/fs/afs/volume.c +++ b/fs/afs/volume.c @@ -51,7 +51,7 @@ static struct afs_volume *afs_alloc_volume(struct afs_fs_context *params, } refcount_set(&slist->usage, 1); - volume->servers = slist; + rcu_assign_pointer(volume->servers, slist); return volume; error_1: @@ -156,7 +156,7 @@ static void afs_destroy_volume(struct afs_net *net, struct afs_volume *volume) ASSERTCMP(volume->cache, ==, NULL); #endif - afs_put_serverlist(net, volume->servers); + afs_put_serverlist(net, rcu_access_pointer(volume->servers)); afs_put_cell(net, volume->cell); kfree(volume); @@ -256,10 +256,11 @@ static int afs_update_volume_status(struct afs_volume *volume, struct key *key) write_lock(&volume->servers_lock); discard = new; - old = volume->servers; + old = rcu_dereference_protected(volume->servers, + lockdep_is_held(&volume->servers_lock)); if (afs_annotate_server_list(new, old)) { new->seq = volume->servers_seq + 1; - volume->servers = new; + rcu_assign_pointer(volume->servers, new); smp_wmb(); volume->servers_seq++; discard = old; |