Revision 774a1221e862b343388347bac9b318767336b20b authored by Tejun Heo on 16 January 2013, 02:52:51 UTC, committed by Linus Torvalds on 16 January 2013, 17:05:33 UTC
If the default iosched is built as module, the kernel may deadlock while trying to load the iosched module on device probe if the probing was running off async. This is because async_synchronize_full() at the end of module init ends up waiting for the async job which initiated the module loading. async A modprobe 1. finds a device 2. registers the block device 3. request_module(default iosched) 4. modprobe in userland 5. load and init module 6. async_synchronize_full() Async A waits for modprobe to finish in request_module() and modprobe waits for async A to finish in async_synchronize_full(). Because there's no easy to track dependency once control goes out to userland, implementing properly nested flushing is difficult. For now, make module init perform async_synchronize_full() iff module init has queued async jobs as suggested by Linus. This avoids the described deadlock because iosched module doesn't use async and thus wouldn't invoke async_synchronize_full(). This is hacky and incomplete. It will deadlock if async module loading nests; however, this works around the known problem case and seems to be the best of bad options. For more details, please refer to the following thread. http://thread.gmane.org/gmane.linux.kernel/1420814 Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Alex Riesen <raa.lkml@gmail.com> Tested-by: Ming Lei <ming.lei@canonical.com> Tested-by: Alex Riesen <raa.lkml@gmail.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 406089d
ceph_common.c
#include <linux/ceph/ceph_debug.h>
#include <linux/backing-dev.h>
#include <linux/ctype.h>
#include <linux/fs.h>
#include <linux/inet.h>
#include <linux/in6.h>
#include <linux/key.h>
#include <keys/ceph-type.h>
#include <linux/module.h>
#include <linux/mount.h>
#include <linux/parser.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/statfs.h>
#include <linux/string.h>
#include <linux/ceph/ceph_features.h>
#include <linux/ceph/libceph.h>
#include <linux/ceph/debugfs.h>
#include <linux/ceph/decode.h>
#include <linux/ceph/mon_client.h>
#include <linux/ceph/auth.h>
#include "crypto.h"
/*
* find filename portion of a path (/foo/bar/baz -> baz)
*/
const char *ceph_file_part(const char *s, int len)
{
const char *e = s + len;
while (e != s && *(e-1) != '/')
e--;
return e;
}
EXPORT_SYMBOL(ceph_file_part);
const char *ceph_msg_type_name(int type)
{
switch (type) {
case CEPH_MSG_SHUTDOWN: return "shutdown";
case CEPH_MSG_PING: return "ping";
case CEPH_MSG_AUTH: return "auth";
case CEPH_MSG_AUTH_REPLY: return "auth_reply";
case CEPH_MSG_MON_MAP: return "mon_map";
case CEPH_MSG_MON_GET_MAP: return "mon_get_map";
case CEPH_MSG_MON_SUBSCRIBE: return "mon_subscribe";
case CEPH_MSG_MON_SUBSCRIBE_ACK: return "mon_subscribe_ack";
case CEPH_MSG_STATFS: return "statfs";
case CEPH_MSG_STATFS_REPLY: return "statfs_reply";
case CEPH_MSG_MDS_MAP: return "mds_map";
case CEPH_MSG_CLIENT_SESSION: return "client_session";
case CEPH_MSG_CLIENT_RECONNECT: return "client_reconnect";
case CEPH_MSG_CLIENT_REQUEST: return "client_request";
case CEPH_MSG_CLIENT_REQUEST_FORWARD: return "client_request_forward";
case CEPH_MSG_CLIENT_REPLY: return "client_reply";
case CEPH_MSG_CLIENT_CAPS: return "client_caps";
case CEPH_MSG_CLIENT_CAPRELEASE: return "client_cap_release";
case CEPH_MSG_CLIENT_SNAP: return "client_snap";
case CEPH_MSG_CLIENT_LEASE: return "client_lease";
case CEPH_MSG_OSD_MAP: return "osd_map";
case CEPH_MSG_OSD_OP: return "osd_op";
case CEPH_MSG_OSD_OPREPLY: return "osd_opreply";
case CEPH_MSG_WATCH_NOTIFY: return "watch_notify";
default: return "unknown";
}
}
EXPORT_SYMBOL(ceph_msg_type_name);
/*
* Initially learn our fsid, or verify an fsid matches.
*/
int ceph_check_fsid(struct ceph_client *client, struct ceph_fsid *fsid)
{
if (client->have_fsid) {
if (ceph_fsid_compare(&client->fsid, fsid)) {
pr_err("bad fsid, had %pU got %pU",
&client->fsid, fsid);
return -1;
}
} else {
memcpy(&client->fsid, fsid, sizeof(*fsid));
}
return 0;
}
EXPORT_SYMBOL(ceph_check_fsid);
static int strcmp_null(const char *s1, const char *s2)
{
if (!s1 && !s2)
return 0;
if (s1 && !s2)
return -1;
if (!s1 && s2)
return 1;
return strcmp(s1, s2);
}
int ceph_compare_options(struct ceph_options *new_opt,
struct ceph_client *client)
{
struct ceph_options *opt1 = new_opt;
struct ceph_options *opt2 = client->options;
int ofs = offsetof(struct ceph_options, mon_addr);
int i;
int ret;
ret = memcmp(opt1, opt2, ofs);
if (ret)
return ret;
ret = strcmp_null(opt1->name, opt2->name);
if (ret)
return ret;
if (opt1->key && !opt2->key)
return -1;
if (!opt1->key && opt2->key)
return 1;
if (opt1->key && opt2->key) {
if (opt1->key->type != opt2->key->type)
return -1;
if (opt1->key->created.tv_sec != opt2->key->created.tv_sec)
return -1;
if (opt1->key->created.tv_nsec != opt2->key->created.tv_nsec)
return -1;
if (opt1->key->len != opt2->key->len)
return -1;
if (opt1->key->key && !opt2->key->key)
return -1;
if (!opt1->key->key && opt2->key->key)
return 1;
if (opt1->key->key && opt2->key->key) {
ret = memcmp(opt1->key->key, opt2->key->key, opt1->key->len);
if (ret)
return ret;
}
}
/* any matching mon ip implies a match */
for (i = 0; i < opt1->num_mon; i++) {
if (ceph_monmap_contains(client->monc.monmap,
&opt1->mon_addr[i]))
return 0;
}
return -1;
}
EXPORT_SYMBOL(ceph_compare_options);
static int parse_fsid(const char *str, struct ceph_fsid *fsid)
{
int i = 0;
char tmp[3];
int err = -EINVAL;
int d;
dout("parse_fsid '%s'\n", str);
tmp[2] = 0;
while (*str && i < 16) {
if (ispunct(*str)) {
str++;
continue;
}
if (!isxdigit(str[0]) || !isxdigit(str[1]))
break;
tmp[0] = str[0];
tmp[1] = str[1];
if (sscanf(tmp, "%x", &d) < 1)
break;
fsid->fsid[i] = d & 0xff;
i++;
str += 2;
}
if (i == 16)
err = 0;
dout("parse_fsid ret %d got fsid %pU", err, fsid);
return err;
}
/*
* ceph options
*/
enum {
Opt_osdtimeout,
Opt_osdkeepalivetimeout,
Opt_mount_timeout,
Opt_osd_idle_ttl,
Opt_last_int,
/* int args above */
Opt_fsid,
Opt_name,
Opt_secret,
Opt_key,
Opt_ip,
Opt_last_string,
/* string args above */
Opt_share,
Opt_noshare,
Opt_crc,
Opt_nocrc,
};
static match_table_t opt_tokens = {
{Opt_osdtimeout, "osdtimeout=%d"},
{Opt_osdkeepalivetimeout, "osdkeepalive=%d"},
{Opt_mount_timeout, "mount_timeout=%d"},
{Opt_osd_idle_ttl, "osd_idle_ttl=%d"},
/* int args above */
{Opt_fsid, "fsid=%s"},
{Opt_name, "name=%s"},
{Opt_secret, "secret=%s"},
{Opt_key, "key=%s"},
{Opt_ip, "ip=%s"},
/* string args above */
{Opt_share, "share"},
{Opt_noshare, "noshare"},
{Opt_crc, "crc"},
{Opt_nocrc, "nocrc"},
{-1, NULL}
};
void ceph_destroy_options(struct ceph_options *opt)
{
dout("destroy_options %p\n", opt);
kfree(opt->name);
if (opt->key) {
ceph_crypto_key_destroy(opt->key);
kfree(opt->key);
}
kfree(opt->mon_addr);
kfree(opt);
}
EXPORT_SYMBOL(ceph_destroy_options);
/* get secret from key store */
static int get_secret(struct ceph_crypto_key *dst, const char *name) {
struct key *ukey;
int key_err;
int err = 0;
struct ceph_crypto_key *ckey;
ukey = request_key(&key_type_ceph, name, NULL);
if (!ukey || IS_ERR(ukey)) {
/* request_key errors don't map nicely to mount(2)
errors; don't even try, but still printk */
key_err = PTR_ERR(ukey);
switch (key_err) {
case -ENOKEY:
pr_warning("ceph: Mount failed due to key not found: %s\n", name);
break;
case -EKEYEXPIRED:
pr_warning("ceph: Mount failed due to expired key: %s\n", name);
break;
case -EKEYREVOKED:
pr_warning("ceph: Mount failed due to revoked key: %s\n", name);
break;
default:
pr_warning("ceph: Mount failed due to unknown key error"
" %d: %s\n", key_err, name);
}
err = -EPERM;
goto out;
}
ckey = ukey->payload.data;
err = ceph_crypto_key_clone(dst, ckey);
if (err)
goto out_key;
/* pass through, err is 0 */
out_key:
key_put(ukey);
out:
return err;
}
struct ceph_options *
ceph_parse_options(char *options, const char *dev_name,
const char *dev_name_end,
int (*parse_extra_token)(char *c, void *private),
void *private)
{
struct ceph_options *opt;
const char *c;
int err = -ENOMEM;
substring_t argstr[MAX_OPT_ARGS];
opt = kzalloc(sizeof(*opt), GFP_KERNEL);
if (!opt)
return ERR_PTR(-ENOMEM);
opt->mon_addr = kcalloc(CEPH_MAX_MON, sizeof(*opt->mon_addr),
GFP_KERNEL);
if (!opt->mon_addr)
goto out;
dout("parse_options %p options '%s' dev_name '%s'\n", opt, options,
dev_name);
/* start with defaults */
opt->flags = CEPH_OPT_DEFAULT;
opt->osd_keepalive_timeout = CEPH_OSD_KEEPALIVE_DEFAULT;
opt->mount_timeout = CEPH_MOUNT_TIMEOUT_DEFAULT; /* seconds */
opt->osd_idle_ttl = CEPH_OSD_IDLE_TTL_DEFAULT; /* seconds */
/* get mon ip(s) */
/* ip1[:port1][,ip2[:port2]...] */
err = ceph_parse_ips(dev_name, dev_name_end, opt->mon_addr,
CEPH_MAX_MON, &opt->num_mon);
if (err < 0)
goto out;
/* parse mount options */
while ((c = strsep(&options, ",")) != NULL) {
int token, intval, ret;
if (!*c)
continue;
err = -EINVAL;
token = match_token((char *)c, opt_tokens, argstr);
if (token < 0 && parse_extra_token) {
/* extra? */
err = parse_extra_token((char *)c, private);
if (err < 0) {
pr_err("bad option at '%s'\n", c);
goto out;
}
continue;
}
if (token < Opt_last_int) {
ret = match_int(&argstr[0], &intval);
if (ret < 0) {
pr_err("bad mount option arg (not int) "
"at '%s'\n", c);
continue;
}
dout("got int token %d val %d\n", token, intval);
} else if (token > Opt_last_int && token < Opt_last_string) {
dout("got string token %d val %s\n", token,
argstr[0].from);
} else {
dout("got token %d\n", token);
}
switch (token) {
case Opt_ip:
err = ceph_parse_ips(argstr[0].from,
argstr[0].to,
&opt->my_addr,
1, NULL);
if (err < 0)
goto out;
opt->flags |= CEPH_OPT_MYIP;
break;
case Opt_fsid:
err = parse_fsid(argstr[0].from, &opt->fsid);
if (err == 0)
opt->flags |= CEPH_OPT_FSID;
break;
case Opt_name:
opt->name = kstrndup(argstr[0].from,
argstr[0].to-argstr[0].from,
GFP_KERNEL);
break;
case Opt_secret:
opt->key = kzalloc(sizeof(*opt->key), GFP_KERNEL);
if (!opt->key) {
err = -ENOMEM;
goto out;
}
err = ceph_crypto_key_unarmor(opt->key, argstr[0].from);
if (err < 0)
goto out;
break;
case Opt_key:
opt->key = kzalloc(sizeof(*opt->key), GFP_KERNEL);
if (!opt->key) {
err = -ENOMEM;
goto out;
}
err = get_secret(opt->key, argstr[0].from);
if (err < 0)
goto out;
break;
/* misc */
case Opt_osdtimeout:
pr_warning("ignoring deprecated osdtimeout option\n");
break;
case Opt_osdkeepalivetimeout:
opt->osd_keepalive_timeout = intval;
break;
case Opt_osd_idle_ttl:
opt->osd_idle_ttl = intval;
break;
case Opt_mount_timeout:
opt->mount_timeout = intval;
break;
case Opt_share:
opt->flags &= ~CEPH_OPT_NOSHARE;
break;
case Opt_noshare:
opt->flags |= CEPH_OPT_NOSHARE;
break;
case Opt_crc:
opt->flags &= ~CEPH_OPT_NOCRC;
break;
case Opt_nocrc:
opt->flags |= CEPH_OPT_NOCRC;
break;
default:
BUG_ON(token);
}
}
/* success */
return opt;
out:
ceph_destroy_options(opt);
return ERR_PTR(err);
}
EXPORT_SYMBOL(ceph_parse_options);
u64 ceph_client_id(struct ceph_client *client)
{
return client->monc.auth->global_id;
}
EXPORT_SYMBOL(ceph_client_id);
/*
* create a fresh client instance
*/
struct ceph_client *ceph_create_client(struct ceph_options *opt, void *private,
unsigned int supported_features,
unsigned int required_features)
{
struct ceph_client *client;
struct ceph_entity_addr *myaddr = NULL;
int err = -ENOMEM;
client = kzalloc(sizeof(*client), GFP_KERNEL);
if (client == NULL)
return ERR_PTR(-ENOMEM);
client->private = private;
client->options = opt;
mutex_init(&client->mount_mutex);
init_waitqueue_head(&client->auth_wq);
client->auth_err = 0;
client->extra_mon_dispatch = NULL;
client->supported_features = CEPH_FEATURES_SUPPORTED_DEFAULT |
supported_features;
client->required_features = CEPH_FEATURES_REQUIRED_DEFAULT |
required_features;
/* msgr */
if (ceph_test_opt(client, MYIP))
myaddr = &client->options->my_addr;
ceph_messenger_init(&client->msgr, myaddr,
client->supported_features,
client->required_features,
ceph_test_opt(client, NOCRC));
/* subsystems */
err = ceph_monc_init(&client->monc, client);
if (err < 0)
goto fail;
err = ceph_osdc_init(&client->osdc, client);
if (err < 0)
goto fail_monc;
return client;
fail_monc:
ceph_monc_stop(&client->monc);
fail:
kfree(client);
return ERR_PTR(err);
}
EXPORT_SYMBOL(ceph_create_client);
void ceph_destroy_client(struct ceph_client *client)
{
dout("destroy_client %p\n", client);
atomic_set(&client->msgr.stopping, 1);
/* unmount */
ceph_osdc_stop(&client->osdc);
ceph_monc_stop(&client->monc);
ceph_debugfs_client_cleanup(client);
ceph_destroy_options(client->options);
kfree(client);
dout("destroy_client %p done\n", client);
}
EXPORT_SYMBOL(ceph_destroy_client);
/*
* true if we have the mon map (and have thus joined the cluster)
*/
static int have_mon_and_osd_map(struct ceph_client *client)
{
return client->monc.monmap && client->monc.monmap->epoch &&
client->osdc.osdmap && client->osdc.osdmap->epoch;
}
/*
* mount: join the ceph cluster, and open root directory.
*/
int __ceph_open_session(struct ceph_client *client, unsigned long started)
{
int err;
unsigned long timeout = client->options->mount_timeout * HZ;
/* open session, and wait for mon and osd maps */
err = ceph_monc_open_session(&client->monc);
if (err < 0)
return err;
while (!have_mon_and_osd_map(client)) {
err = -EIO;
if (timeout && time_after_eq(jiffies, started + timeout))
return err;
/* wait */
dout("mount waiting for mon_map\n");
err = wait_event_interruptible_timeout(client->auth_wq,
have_mon_and_osd_map(client) || (client->auth_err < 0),
timeout);
if (err == -EINTR || err == -ERESTARTSYS)
return err;
if (client->auth_err < 0)
return client->auth_err;
}
return 0;
}
EXPORT_SYMBOL(__ceph_open_session);
int ceph_open_session(struct ceph_client *client)
{
int ret;
unsigned long started = jiffies; /* note the start time */
dout("open_session start\n");
mutex_lock(&client->mount_mutex);
ret = __ceph_open_session(client, started);
mutex_unlock(&client->mount_mutex);
return ret;
}
EXPORT_SYMBOL(ceph_open_session);
static int __init init_ceph_lib(void)
{
int ret = 0;
ret = ceph_debugfs_init();
if (ret < 0)
goto out;
ret = ceph_crypto_init();
if (ret < 0)
goto out_debugfs;
ret = ceph_msgr_init();
if (ret < 0)
goto out_crypto;
pr_info("loaded (mon/osd proto %d/%d, osdmap %d/%d %d/%d)\n",
CEPH_MONC_PROTOCOL, CEPH_OSDC_PROTOCOL,
CEPH_OSDMAP_VERSION, CEPH_OSDMAP_VERSION_EXT,
CEPH_OSDMAP_INC_VERSION, CEPH_OSDMAP_INC_VERSION_EXT);
return 0;
out_crypto:
ceph_crypto_shutdown();
out_debugfs:
ceph_debugfs_cleanup();
out:
return ret;
}
static void __exit exit_ceph_lib(void)
{
dout("exit_ceph_lib\n");
ceph_msgr_exit();
ceph_crypto_shutdown();
ceph_debugfs_cleanup();
}
module_init(init_ceph_lib);
module_exit(exit_ceph_lib);
MODULE_AUTHOR("Sage Weil <sage@newdream.net>");
MODULE_AUTHOR("Yehuda Sadeh <yehuda@hq.newdream.net>");
MODULE_AUTHOR("Patience Warnick <patience@newdream.net>");
MODULE_DESCRIPTION("Ceph filesystem for Linux");
MODULE_LICENSE("GPL");
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