Re: [nfs-utils PATCH RFC 3/7] nfsdcld: a few enhancements

Jeff Layton
2018-11-10T14:16:56Z

On Tue, 2018-11-06 at 13:36 -0500, Scott Mayhew wrote:
> 1) Adopt the concept of "reboot epochs" (but not coordinated grace
> periods via the "need" and "enforcing" flags) from Jeff Layton's
> "Active/Active NFS Server Recovery" presentation from the Fall 2018 NFS
> Bakeathon. See
> http://nfsv4bat.org/Documents/BakeAThon/2018/Active_Active%20NFS%20Server%20Recovery.pdf
>
> - add a new table "grace" which contains two integer columns
> representing the "current" epoch (where new client records are stored)
> and the "recovery" epoch (which has the records for clients that are
> allowed to recover)
> - replace the "clients" table with table(s) named "rec-CCCCCCCCCCCCCCCC"
> (where C is the hex value of the epoch), containing a single column
> "id" which stores the client id string
> - when going from normal operation into grace, the current epoch becomes
> the recovery epoch, the current epoch is incremented, and a new table
> is created for the current epoch. Clients are allowed to reclaim if
> they have a record in the table corresponding to the recovery epoch
> and new records are added to the table corresponding to the current
> epoch.
> - when moving from grace back to normal operation, the table associated
> with the recovery epoch is deleted and the recovery epoch becomes
> zero.
> - if the server restarts before exiting the previous grace period, then
> the epochs are not changed, and all records in the table associated
> with the "current" epoch are cleared out.
>
> 2) Allow knfsd to "slurp" the client records during startup.
>
> During client tracking initialization, knfsd will do an upcall to get a
> list of clients from the database. nfsdcld will do one downcall with a
> status of -EINPROGRESS for each client record in the database, followed
> by a final downcall with a status of 0. This will allow 2 things
>
> - knfsd can check whether a client is allowed to reclaim without
> performing an upcall to nfsdcld
> - knfsd can decide to end the grace period early by tracking the number
> of RECLAIM_COMPLETE operations it receives from "known" clients, or
> it can skip the grace period altogether if no clients are allowed
> to reclaim.
>

Thanks for doing this work, Scott. This should give us an even more
robust recovery backend that is suitable for containerization, and
possibly something we could extend to do active/active clustered NFS
properly with knfsd.

The changes look great overall -- one minor thing inline below:

> Signed-off-by: Scott Mayhew <smayhew@redhat.com>
> ---
> support/include/cld.h | 1 +
> utils/nfsdcld/Makefile.am | 2 +-
> utils/nfsdcld/cld-internal.h | 30 +++
> utils/nfsdcld/nfsdcld.c | 160 +++++++++++-
> utils/nfsdcld/sqlite.c | 483 ++++++++++++++++++++++++++++-------
> utils/nfsdcld/sqlite.h | 11 +-
> 6 files changed, 579 insertions(+), 108 deletions(-)
> create mode 100644 utils/nfsdcld/cld-internal.h
>
> diff --git a/support/include/cld.h b/support/include/cld.h
> index f14a9ab..c1f5b70 100644
> --- a/support/include/cld.h
> +++ b/support/include/cld.h
> @@ -33,6 +33,7 @@ enum cld_command {
> Cld_Remove, /* remove record of this cm_id */
> Cld_Check, /* is this cm_id allowed? */
> Cld_GraceDone, /* grace period is complete */
> + Cld_GraceStart,
> };
>
> /* representation of long-form NFSv4 client ID */
> diff --git a/utils/nfsdcld/Makefile.am b/utils/nfsdcld/Makefile.am
> index 8239be8..d1da749 100644
> --- a/utils/nfsdcld/Makefile.am
> +++ b/utils/nfsdcld/Makefile.am
> @@ -13,7 +13,7 @@ sbin_PROGRAMS = nfsdcld
> nfsdcld_SOURCES = nfsdcld.c sqlite.c
> nfsdcld_LDADD = ../../support/nfs/libnfs.la $(LIBEVENT) $(LIBSQLITE) $(LIBCAP)
>
> -noinst_HEADERS = sqlite.h
> +noinst_HEADERS = sqlite.h cld-internal.h
>
> MAINTAINERCLEANFILES = Makefile.in
>
> diff --git a/utils/nfsdcld/cld-internal.h b/utils/nfsdcld/cld-internal.h
> new file mode 100644
> index 0000000..a90cced
> --- /dev/null
> +++ b/utils/nfsdcld/cld-internal.h
> @@ -0,0 +1,30 @@
> +/*
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * as published by the Free Software Foundation; either version 2
> + * of the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor,
> + * Boston, MA 02110-1301, USA.
> + */
> +
> +#ifndef _CLD_INTERNAL_H_
> +#define _CLD_INTERNAL_H_
> +
> +struct cld_client {
> + int cl_fd;
> + struct event cl_event;
> + struct cld_msg cl_msg;
> +};
> +
> +uint64_t current_epoch;
> +uint64_t recovery_epoch;
> +
> +#endif /* _CLD_INTERNAL_H_ */
> diff --git a/utils/nfsdcld/nfsdcld.c b/utils/nfsdcld/nfsdcld.c
> index 082f3ab..9b1ad98 100644
> --- a/utils/nfsdcld/nfsdcld.c
> +++ b/utils/nfsdcld/nfsdcld.c
> @@ -42,7 +42,9 @@
> #include "xlog.h"
> #include "nfslib.h"
> #include "cld.h"
> +#include "cld-internal.h"
> #include "sqlite.h"
> +#include "../mount/version.h"
>
> #ifndef PIPEFS_DIR
> #define PIPEFS_DIR NFS_STATEDIR "/rpc_pipefs"
> @@ -54,19 +56,17 @@
> #define CLD_DEFAULT_STORAGEDIR NFS_STATEDIR "/nfsdcld"
> #endif
>
> +#define NFSD_END_GRACE_FILE "/proc/fs/nfsd/v4_end_grace"
> +
> #define UPCALL_VERSION 1
>
> /* private data structures */
> -struct cld_client {
> - int cl_fd;
> - struct event cl_event;
> - struct cld_msg cl_msg;
> -};
>
> /* global variables */
> static char *pipepath = DEFAULT_CLD_PATH;
> static int inotify_fd = -1;
> static struct event pipedir_event;
> +static bool old_kernel = false;
>
> static struct option longopts[] =
> {
> @@ -298,6 +298,43 @@ out:
> return ret;
> }
>
> +/*
> + * Older kernels will not tell nfsdcld when a grace period has started.
> + * Therefore we have to peek at the /proc/fs/nfsd/v4_end_grace file to
> + * see if nfsd is in grace. We have to do this for create and remove
> + * upcalls to ensure that the correct table is being updated - otherwise
> + * we could lose client records when the grace period is lifted.
> + */
> +static int
> +cld_check_grace_period(void)
> +{
> + int fd, ret = 0;
> + char c;
> +
> + if (!old_kernel)
> + return 0;
> + if (recovery_epoch != 0)
> + return 0;
> + fd = open(NFSD_END_GRACE_FILE, O_RDONLY);
> + if (fd < 0) {
> + xlog(L_WARNING, "Unable to open %s: %m",
> + NFSD_END_GRACE_FILE);
> + return 1;
> + }
> + if (read(fd, &c, 1) < 0) {
> + xlog(L_WARNING, "Unable to read from %s: %m",
> + NFSD_END_GRACE_FILE);
> + return 1;
> + }
> + close(fd);
> + if (c == 'N') {
> + xlog(L_WARNING, "nfsd is in grace but didn't send a gracestart upcall, "
> + "please update the kernel");
> + ret = sqlite_grace_start();
> + }
> + return ret;
> +}
> +
> static void
> cld_not_implemented(struct cld_client *clnt)
> {
> @@ -332,14 +369,17 @@ cld_create(struct cld_client *clnt)
> ssize_t bsize, wsize;
> struct cld_msg *cmsg = &clnt->cl_msg;
>
> + ret = cld_check_grace_period();
> + if (ret)
> + goto reply;
> +
> xlog(D_GENERAL, "%s: create client record.", __func__);
>
>
> ret = sqlite_insert_client(cmsg->cm_u.cm_name.cn_id,
> - cmsg->cm_u.cm_name.cn_len,
> - false,
> - false);
> + cmsg->cm_u.cm_name.cn_len);
>
> +reply:
> cmsg->cm_status = ret ? -EREMOTEIO : ret;
>
> bsize = sizeof(*cmsg);
> @@ -365,11 +405,16 @@ cld_remove(struct cld_client *clnt)
> ssize_t bsize, wsize;
> struct cld_msg *cmsg = &clnt->cl_msg;
>
> + ret = cld_check_grace_period();
> + if (ret)
> + goto reply;
> +
> xlog(D_GENERAL, "%s: remove client record.", __func__);
>
> ret = sqlite_remove_client(cmsg->cm_u.cm_name.cn_id,
> cmsg->cm_u.cm_name.cn_len);
>
> +reply:
> cmsg->cm_status = ret ? -EREMOTEIO : ret;
>
> bsize = sizeof(*cmsg);
> @@ -396,12 +441,26 @@ cld_check(struct cld_client *clnt)
> ssize_t bsize, wsize;
> struct cld_msg *cmsg = &clnt->cl_msg;
>
> + /*
> + * If we get a check upcall at all, it means we're talking to an old
> + * kernel. Furthermore, if we're not in grace it means this is the
> + * first client to do a reclaim. Log a message and use
> + * sqlite_grace_start() to advance the epoch numbers.
> + */
> + if (recovery_epoch == 0) {
> + xlog(D_GENERAL, "%s: received a check upcall, please update the kernel",
> + __func__);
> + ret = sqlite_grace_start();
> + if (ret)
> + goto reply;
> + }
> +
> xlog(D_GENERAL, "%s: check client record", __func__);
>
> ret = sqlite_check_client(cmsg->cm_u.cm_name.cn_id,
> - cmsg->cm_u.cm_name.cn_len,
> - false);
> + cmsg->cm_u.cm_name.cn_len);
>
> +reply:
> /* set up reply */
> cmsg->cm_status = ret ? -EACCES : ret;
>
> @@ -429,11 +488,27 @@ cld_gracedone(struct cld_client *clnt)
> ssize_t bsize, wsize;
> struct cld_msg *cmsg = &clnt->cl_msg;
>
> - xlog(D_GENERAL, "%s: grace done. cm_gracetime=%ld", __func__,
> - cmsg->cm_u.cm_gracetime);
> + /*
> + * If we got a "gracedone" upcall while we're not in grace, then
> + * 1) we must be talking to an old kernel
> + * 2) no clients attempted to reclaim
> + * In that case, log a message and use sqlite_grace_start() to
> + * advance the epoch numbers, and then proceed as normal.
> + */
> + if (recovery_epoch == 0) {
> + xlog(D_GENERAL, "%s: received gracedone upcall "
> + "while not in grace, please update the kernel",
> + __func__);
> + ret = sqlite_grace_start();
> + if (ret)
> + goto reply;
> + }
> +
> + xlog(D_GENERAL, "%s: grace done.", __func__);
>
> - ret = sqlite_remove_unreclaimed(cmsg->cm_u.cm_gracetime);
> + ret = sqlite_grace_done();
>
> +reply:
> /* set up reply: downcall with 0 status */
> cmsg->cm_status = ret ? -EREMOTEIO : ret;
>
> @@ -453,6 +528,59 @@ cld_gracedone(struct cld_client *clnt)
> }
> }
>
> +static int
> +gracestart_callback(struct cld_client *clnt) {
> + ssize_t bsize, wsize;
> + struct cld_msg *cmsg = &clnt->cl_msg;
> +
> + cmsg->cm_status = -EINPROGRESS;
> +
> + bsize = sizeof(struct cld_msg);
> +
> + xlog(D_GENERAL, "Sending client %.*s",
> + cmsg->cm_u.cm_name.cn_len, cmsg->cm_u.cm_name.cn_id);
> + wsize = atomicio((void *)write, clnt->cl_fd, cmsg, bsize);
> + if (wsize != bsize)
> + return -EIO;
> + return 0;
> +}
> +
> +static void
> +cld_gracestart(struct cld_client *clnt)
> +{
> + int ret;
> + ssize_t bsize, wsize;
> + struct cld_msg *cmsg = &clnt->cl_msg;
> +
> + xlog(D_GENERAL, "%s: updating grace epochs", __func__);
> +
> + ret = sqlite_grace_start();
> + if (ret)
> + goto reply;
> +
> + xlog(D_GENERAL, "%s: sending client records to the kernel", __func__);
> +
> + ret = sqlite_iterate_recovery(&gracestart_callback, clnt);
> +
> +reply:
> + /* set up reply: downcall with 0 status */
> + cmsg->cm_status = ret ? -EREMOTEIO : ret;
> +
> + bsize = sizeof(struct cld_msg);
> + xlog(D_GENERAL, "Doing downcall with status %d", cmsg->cm_status);
> + wsize = atomicio((void *)write, clnt->cl_fd, cmsg, bsize);
> + if (wsize != bsize) {
> + xlog(L_ERROR, "%s: problem writing to cld pipe (%ld): %m",
> + __func__, wsize);
> + ret = cld_pipe_open(clnt);
> + if (ret) {
> + xlog(L_FATAL, "%s: unable to reopen pipe: %d",
> + __func__, ret);
> + exit(ret);
> + }
> + }
> +}
> +
> static void
> cldcb(int UNUSED(fd), short which, void *data)
> {
> @@ -490,6 +618,9 @@ cldcb(int UNUSED(fd), short which, void *data)
> case Cld_GraceDone:
> cld_gracedone(clnt);
> break;
> + case Cld_GraceStart:
> + cld_gracestart(clnt);
> + break;
> default:
> xlog(L_WARNING, "%s: command %u is not yet implemented",
> __func__, cmsg->cm_cmd);
> @@ -586,6 +717,9 @@ main(int argc, char **argv)
> }
> }
>
> + if (linux_version_code() < MAKE_VERSION(4, 20, 0))
> + old_kernel = true;
> +
> /* set up storage db */
> rc = sqlite_prepare_dbh(storagedir);
> if (rc) {
> diff --git a/utils/nfsdcld/sqlite.c b/utils/nfsdcld/sqlite.c
> index c59f777..67549c9 100644
> --- a/utils/nfsdcld/sqlite.c
> +++ b/utils/nfsdcld/sqlite.c
> @@ -21,17 +21,24 @@
> * Explanation:
> *
> * This file contains the code to manage the sqlite backend database for the
> - * nfsdcltrack usermodehelper upcall program.
> + * nfsdcld client tracking daemon.
> *
> * The main database is called main.sqlite and contains the following tables:
> *
> * parameters: simple key/value pairs for storing database info
> *
> - * clients: an "id" column containing a BLOB with the long-form clientid as
> - * sent by the client, a "time" column containing a timestamp (in
> - * epoch seconds) of when the record was last updated, and a
> - * "has_session" column containing a boolean value indicating
> - * whether the client has sessions (v4.1+) or not (v4.0).
> + * grace: a "current" column containing an INTEGER representing the current
> + * epoch (where should new values be stored) and a "recovery" column
> + * containing an INTEGER representing the recovery epoch (from what
> + * epoch are we allowed to recover). A recovery epoch of 0 means
> + * normal operation (grace period not in force). Note: sqlite stores
> + * integers as signed values, so these must be cast to a uint64_t when
> + * retrieving them from the database and back to an int64_t when storing
> + * them in the database.
> + *
> + * rec-CCCCCCCCCCCCCCCC (where C is the hex representation of the epoch value):
> + * a single "id" column containing a BLOB with the long-form clientid
> + * as sent by the client.
> */
>
> #ifdef HAVE_CONFIG_H
> @@ -47,16 +54,21 @@
> #include <sys/types.h>
> #include <fcntl.h>
> #include <unistd.h>
> +#include <stdlib.h>
> +#include <stdint.h>
> +#include <limits.h>
> #include <sqlite3.h>
> #include <linux/limits.h>
>
> #include "xlog.h"
> #include "sqlite.h"
> +#include "cld.h"
> +#include "cld-internal.h"
>
> -#define CLTRACK_SQLITE_LATEST_SCHEMA_VERSION 2
> +#define CLD_SQLITE_LATEST_SCHEMA_VERSION 3
>
> /* in milliseconds */
> -#define CLTRACK_SQLITE_BUSY_TIMEOUT 10000
> +#define CLD_SQLITE_BUSY_TIMEOUT 10000
>
> /* private data structures */
>
> @@ -124,7 +136,7 @@ out:
> }
>
> static int
> -sqlite_maindb_update_v1_to_v2(void)
> +sqlite_maindb_update_schema(int oldversion)
> {
> int ret, ret2;
> char *err;
> @@ -142,32 +154,66 @@ sqlite_maindb_update_v1_to_v2(void)
> * transaction to guard against racing DB setup attempts
> */
> ret = sqlite_query_schema_version();
> - switch (ret) {
> - case 1:
> - /* Still at v1 -- do conversion */
> - break;
> - case CLTRACK_SQLITE_LATEST_SCHEMA_VERSION:
> - /* Someone else raced in and set it up */
> - ret = 0;
> + if (ret != oldversion) {
> + if (ret == CLD_SQLITE_LATEST_SCHEMA_VERSION)
> + /* Someone else raced in and set it up */
> + ret = 0;
> + else
> + /* Something went wrong -- fail! */
> + ret = -EINVAL;
> goto rollback;
> - default:
> - /* Something went wrong -- fail! */
> - ret = -EINVAL;
> + }
> +
> + /* Still at old version -- do conversion */
> +
> + /* create grace table */
> + ret = sqlite3_exec(dbh, "CREATE TABLE grace "
> + "(current INTEGER , recovery INTEGER);",
> + NULL, NULL, &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to create grace table: %s", err);
> + goto rollback;
> + }
> +
> + /* insert initial epochs into grace table */
> + ret = sqlite3_exec(dbh, "INSERT OR FAIL INTO grace "
> + "values (1, 0);",
> + NULL, NULL, &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to set initial epochs: %s", err);
> + goto rollback;
> + }
> +
> + /* create recovery table for current epoch */
> + ret = sqlite3_exec(dbh, "CREATE TABLE \"rec-0000000000000001\" "
> + "(id BLOB PRIMARY KEY);",
> + NULL, NULL, &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to create recovery table "
> + "for current epoch: %s", err);
> + goto rollback;
> + }
> +
> + /* copy records from old clients table */
> + ret = sqlite3_exec(dbh, "INSERT INTO \"rec-0000000000000001\" "
> + "SELECT id FROM clients;",
> + NULL, NULL, &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to copy client records: %s", err);
> goto rollback;
> }
>
> - /* create v2 clients table */
> - ret = sqlite3_exec(dbh, "ALTER TABLE clients ADD COLUMN "
> - "has_session INTEGER;",
> + /* drop the old clients table */
> + ret = sqlite3_exec(dbh, "DROP TABLE clients;",
> NULL, NULL, &err);
> if (ret != SQLITE_OK) {
> - xlog(L_ERROR, "Unable to update clients table: %s", err);
> + xlog(L_ERROR, "Unable to drop old clients table: %s", err);
> goto rollback;
> }
>
> ret = snprintf(buf, sizeof(buf), "UPDATE parameters SET value = %d "
> "WHERE key = \"version\";",
> - CLTRACK_SQLITE_LATEST_SCHEMA_VERSION);
> + CLD_SQLITE_LATEST_SCHEMA_VERSION);
> if (ret < 0) {
> xlog(L_ERROR, "sprintf failed!");
> goto rollback;
> @@ -205,7 +251,7 @@ rollback:
> * transaction. On any error, rollback the transaction.
> */
> static int
> -sqlite_maindb_init_v2(void)
> +sqlite_maindb_init_v3(void)
> {
> int ret, ret2;
> char *err = NULL;
> @@ -227,7 +273,7 @@ sqlite_maindb_init_v2(void)
> case 0:
> /* Query failed again -- set up DB */
> break;
> - case CLTRACK_SQLITE_LATEST_SCHEMA_VERSION:
> + case CLD_SQLITE_LATEST_SCHEMA_VERSION:
> /* Someone else raced in and set it up */
> ret = 0;
> goto rollback;
> @@ -245,20 +291,38 @@ sqlite_maindb_init_v2(void)
> goto rollback;
> }
>
> - /* create the "clients" table */
> - ret = sqlite3_exec(dbh, "CREATE TABLE clients (id BLOB PRIMARY KEY, "
> - "time INTEGER, has_session INTEGER);",
> + /* create grace table */
> + ret = sqlite3_exec(dbh, "CREATE TABLE grace "
> + "(current INTEGER , recovery INTEGER);",
> NULL, NULL, &err);
> if (ret != SQLITE_OK) {
> - xlog(L_ERROR, "Unable to create clients table: %s", err);
> + xlog(L_ERROR, "Unable to create grace table: %s", err);
> goto rollback;
> }
>
> + /* insert initial epochs into grace table */
> + ret = sqlite3_exec(dbh, "INSERT OR FAIL INTO grace "
> + "values (1, 0);",
> + NULL, NULL, &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to set initial epochs: %s", err);
> + goto rollback;
> + }
> +
> + /* create recovery table for current epoch */
> + ret = sqlite3_exec(dbh, "CREATE TABLE \"rec-0000000000000001\" "
> + "(id BLOB PRIMARY KEY);",
> + NULL, NULL, &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to create recovery table "
> + "for current epoch: %s", err);
> + goto rollback;
> + }
>
> /* insert version into parameters table */
> ret = snprintf(buf, sizeof(buf), "INSERT OR FAIL INTO parameters "
> "values (\"version\", \"%d\");",
> - CLTRACK_SQLITE_LATEST_SCHEMA_VERSION);
> + CLD_SQLITE_LATEST_SCHEMA_VERSION);
> if (ret < 0) {
> xlog(L_ERROR, "sprintf failed!");
> goto rollback;
> @@ -291,6 +355,42 @@ rollback:
> goto out;
> }
>
> +static int
> +sqlite_startup_query_grace(void)
> +{
> + int ret;
> + uint64_t tcur;
> + uint64_t trec;
> + sqlite3_stmt *stmt = NULL;
> +
> + /* prepare select query */
> + ret = sqlite3_prepare_v2(dbh, "SELECT * FROM grace;", -1, &stmt, NULL);
> + if (ret != SQLITE_OK) {
> + xlog(D_GENERAL, "Unable to prepare select statement: %s",
> + sqlite3_errmsg(dbh));
> + goto out;
> + }
> +
> + ret = sqlite3_step(stmt);
> + if (ret != SQLITE_ROW) {
> + xlog(D_GENERAL, "Select statement execution failed: %s",
> + sqlite3_errmsg(dbh));
> + goto out;
> + }
> +
> + tcur = (uint64_t)sqlite3_column_int(stmt, 0);
> + trec = (uint64_t)sqlite3_column_int(stmt, 1);

I think you want to use sqlite3_column_int64 here:

https://www.sqlite.org/c3ref/column_blob.html

> +
> + current_epoch = tcur;
> + recovery_epoch = trec;
> + ret = 0;
> + xlog(D_GENERAL, "%s: current_epoch=%lu recovery_epoch=%lu",
> + __func__, current_epoch, recovery_epoch);
> +out:
> + sqlite3_finalize(stmt);
> + return ret;
> +}
> +
> /* Open the database and set up the database handle for it */
> int
> sqlite_prepare_dbh(const char *topdir)
> @@ -322,7 +422,7 @@ sqlite_prepare_dbh(const char *topdir)
> }
>
> /* set busy timeout */
> - ret = sqlite3_busy_timeout(dbh, CLTRACK_SQLITE_BUSY_TIMEOUT);
> + ret = sqlite3_busy_timeout(dbh, CLD_SQLITE_BUSY_TIMEOUT);
> if (ret != SQLITE_OK) {
> xlog(L_ERROR, "Unable to set sqlite busy timeout: %s",
> sqlite3_errmsg(dbh));
> @@ -331,19 +431,26 @@ sqlite_prepare_dbh(const char *topdir)
>
> ret = sqlite_query_schema_version();
> switch (ret) {
> - case CLTRACK_SQLITE_LATEST_SCHEMA_VERSION:
> + case CLD_SQLITE_LATEST_SCHEMA_VERSION:
> /* DB is already set up. Do nothing */
> ret = 0;
> break;
> + case 2:
> + /* Old DB -- update to new schema */
> + ret = sqlite_maindb_update_schema(2);
> + if (ret)
> + goto out_close;
> + break;
> +
> case 1:
> /* Old DB -- update to new schema */
> - ret = sqlite_maindb_update_v1_to_v2();
> + ret = sqlite_maindb_update_schema(1);
> if (ret)
> goto out_close;
> break;
> case 0:
> /* Query failed -- try to set up new DB */
> - ret = sqlite_maindb_init_v2();
> + ret = sqlite_maindb_init_v3();
> if (ret)
> goto out_close;
> break;
> @@ -351,11 +458,13 @@ sqlite_prepare_dbh(const char *topdir)
> /* Unknown DB version -- downgrade? Fail */
> xlog(L_ERROR, "Unsupported database schema version! "
> "Expected %d, got %d.",
> - CLTRACK_SQLITE_LATEST_SCHEMA_VERSION, ret);
> + CLD_SQLITE_LATEST_SCHEMA_VERSION, ret);
> ret = -EINVAL;
> goto out_close;
> }
>
> + ret = sqlite_startup_query_grace();
> +
> return ret;
> out_close:
> sqlite3_close(dbh);
> @@ -369,20 +478,22 @@ out_close:
> * Returns a non-zero sqlite error code, or SQLITE_OK (aka 0)
> */
> int
> -sqlite_insert_client(const unsigned char *clname, const size_t namelen,
> - const bool has_session, const bool zerotime)
> +sqlite_insert_client(const unsigned char *clname, const size_t namelen)
> {
> int ret;
> sqlite3_stmt *stmt = NULL;
>
> - if (zerotime)
> - ret = sqlite3_prepare_v2(dbh, "INSERT OR REPLACE INTO clients "
> - "VALUES (?, 0, ?);", -1, &stmt, NULL);
> - else
> - ret = sqlite3_prepare_v2(dbh, "INSERT OR REPLACE INTO clients "
> - "VALUES (?, strftime('%s', 'now'), ?);", -1,
> - &stmt, NULL);
> + ret = snprintf(buf, sizeof(buf), "INSERT OR REPLACE INTO \"rec-%016lx\" "
> + "VALUES (?);", current_epoch);
> + if (ret < 0) {
> + xlog(L_ERROR, "sprintf failed!");
> + return ret;
> + } else if ((size_t)ret >= sizeof(buf)) {
> + xlog(L_ERROR, "sprintf output too long! (%d chars)", ret);
> + return -EINVAL;
> + }
>
> + ret = sqlite3_prepare_v2(dbh, buf, -1, &stmt, NULL);
> if (ret != SQLITE_OK) {
> xlog(L_ERROR, "%s: insert statement prepare failed: %s",
> __func__, sqlite3_errmsg(dbh));
> @@ -397,13 +508,6 @@ sqlite_insert_client(const unsigned char *clname, const size_t namelen,
> goto out_err;
> }
>
> - ret = sqlite3_bind_int(stmt, 2, (int)has_session);
> - if (ret != SQLITE_OK) {
> - xlog(L_ERROR, "%s: bind int failed: %s", __func__,
> - sqlite3_errmsg(dbh));
> - goto out_err;
> - }
> -
> ret = sqlite3_step(stmt);
> if (ret == SQLITE_DONE)
> ret = SQLITE_OK;
> @@ -424,8 +528,18 @@ sqlite_remove_client(const unsigned char *clname, const size_t namelen)
> int ret;
> sqlite3_stmt *stmt = NULL;
>
> - ret = sqlite3_prepare_v2(dbh, "DELETE FROM clients WHERE id==?", -1,
> - &stmt, NULL);
> + ret = snprintf(buf, sizeof(buf), "DELETE FROM \"rec-%016lx\" "
> + "WHERE id==?;", current_epoch);
> + if (ret < 0) {
> + xlog(L_ERROR, "sprintf failed!");
> + return ret;
> + } else if ((size_t)ret >= sizeof(buf)) {
> + xlog(L_ERROR, "sprintf output too long! (%d chars)", ret);
> + return -EINVAL;
> + }
> +
> + ret = sqlite3_prepare_v2(dbh, buf, -1, &stmt, NULL);
> +
> if (ret != SQLITE_OK) {
> xlog(L_ERROR, "%s: statement prepare failed: %s",
> __func__, sqlite3_errmsg(dbh));
> @@ -459,18 +573,26 @@ out_err:
> * return an error.
> */
> int
> -sqlite_check_client(const unsigned char *clname, const size_t namelen,
> - const bool has_session)
> +sqlite_check_client(const unsigned char *clname, const size_t namelen)
> {
> int ret;
> sqlite3_stmt *stmt = NULL;
>
> - ret = sqlite3_prepare_v2(dbh, "SELECT count(*) FROM clients WHERE "
> - "id==?", -1, &stmt, NULL);
> + ret = snprintf(buf, sizeof(buf), "SELECT count(*) FROM \"rec-%016lx\" "
> + "WHERE id==?;", recovery_epoch);
> + if (ret < 0) {
> + xlog(L_ERROR, "sprintf failed!");
> + return ret;
> + } else if ((size_t)ret >= sizeof(buf)) {
> + xlog(L_ERROR, "sprintf output too long! (%d chars)", ret);
> + return -EINVAL;
> + }
> +
> + ret = sqlite3_prepare_v2(dbh, buf, -1, &stmt, NULL);
> if (ret != SQLITE_OK) {
> - xlog(L_ERROR, "%s: unable to prepare update statement: %s",
> - __func__, sqlite3_errmsg(dbh));
> - goto out_err;
> + xlog(L_ERROR, "%s: select statement prepare failed: %s",
> + __func__, sqlite3_errmsg(dbh));
> + return ret;
> }
>
> ret = sqlite3_bind_blob(stmt, 1, (const void *)clname, namelen,
> @@ -495,37 +617,10 @@ sqlite_check_client(const unsigned char *clname, const size_t namelen,
> goto out_err;
> }
>
> - /* Only update timestamp for v4.0 clients */
> - if (has_session) {
> - ret = SQLITE_OK;
> - goto out_err;
> - }
> -
> sqlite3_finalize(stmt);
> - stmt = NULL;
> - ret = sqlite3_prepare_v2(dbh, "UPDATE OR FAIL clients SET "
> - "time=strftime('%s', 'now') WHERE id==?",
> - -1, &stmt, NULL);
> - if (ret != SQLITE_OK) {
> - xlog(L_ERROR, "%s: unable to prepare update statement: %s",
> - __func__, sqlite3_errmsg(dbh));
> - goto out_err;
> - }
>
> - ret = sqlite3_bind_blob(stmt, 1, (const void *)clname, namelen,
> - SQLITE_STATIC);
> - if (ret != SQLITE_OK) {
> - xlog(L_ERROR, "%s: bind blob failed: %s",
> - __func__, sqlite3_errmsg(dbh));
> - goto out_err;
> - }
> -
> - ret = sqlite3_step(stmt);
> - if (ret == SQLITE_DONE)
> - ret = SQLITE_OK;
> - else
> - xlog(L_ERROR, "%s: unexpected return code from update: %s",
> - __func__, sqlite3_errmsg(dbh));
> + /* Now insert the client into the table for the current epoch */
> + return sqlite_insert_client(clname, namelen);
>
> out_err:
> xlog(D_GENERAL, "%s: returning %d", __func__, ret);
> @@ -599,3 +694,211 @@ sqlite_query_reclaiming(const time_t grace_start)
> "reclaim", __func__, ret);
> return ret;
> }
> +
> +int
> +sqlite_grace_start(void)
> +{
> + int ret, ret2;
> + char *err;
> + uint64_t tcur = current_epoch;
> + uint64_t trec = recovery_epoch;
> +
> + /* begin transaction */
> + ret = sqlite3_exec(dbh, "BEGIN EXCLUSIVE TRANSACTION;", NULL, NULL,
> + &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to begin transaction: %s", err);
> + goto rollback;
> + }
> +
> + if (trec == 0) {
> + /*
> + * A normal grace start - update the epoch values in the grace
> + * table and create a new table for the current reboot epoch.
> + */
> + trec = tcur;
> + tcur++;
> +
> + ret = snprintf(buf, sizeof(buf), "UPDATE grace "
> + "SET current = %ld, recovery = %ld;",
> + (int64_t)tcur, (int64_t)trec);
> + if (ret < 0) {
> + xlog(L_ERROR, "sprintf failed!");
> + goto rollback;
> + } else if ((size_t)ret >= sizeof(buf)) {
> + xlog(L_ERROR, "sprintf output too long! (%d chars)",
> + ret);
> + ret = -EINVAL;
> + goto rollback;
> + }
> +
> + ret = sqlite3_exec(dbh, (const char *)buf, NULL, NULL, &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to update epochs: %s", err);
> + goto rollback;
> + }
> +
> + ret = snprintf(buf, sizeof(buf), "CREATE TABLE \"rec-%016lx\" "
> + "(id BLOB PRIMARY KEY);",
> + tcur);
> + if (ret < 0) {
> + xlog(L_ERROR, "sprintf failed!");
> + goto rollback;
> + } else if ((size_t)ret >= sizeof(buf)) {
> + xlog(L_ERROR, "sprintf output too long! (%d chars)",
> + ret);
> + ret = -EINVAL;
> + goto rollback;
> + }
> +
> + ret = sqlite3_exec(dbh, (const char *)buf, NULL, NULL, &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to create table for current epoch: %s",
> + err);
> + goto rollback;
> + }
> + } else {
> + /* Server restarted while in grace - don't update the epoch
> + * values in the grace table, just clear out the records for
> + * the current reboot epoch.
> + */
> + ret = snprintf(buf, sizeof(buf), "DELETE FROM \"rec-%016lx\";",
> + tcur);
> + if (ret < 0) {
> + xlog(L_ERROR, "sprintf failed!");
> + goto rollback;
> + } else if ((size_t)ret >= sizeof(buf)) {
> + xlog(L_ERROR, "sprintf output too long! (%d chars)", ret);
> + ret = -EINVAL;
> + goto rollback;
> + }
> +
> + ret = sqlite3_exec(dbh, (const char *)buf, NULL, NULL, &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to clear table for current epoch: %s",
> + err);
> + goto rollback;
> + }
> + }
> +
> + ret = sqlite3_exec(dbh, "COMMIT TRANSACTION;", NULL, NULL, &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to commit transaction: %s", err);
> + goto rollback;
> + }
> +
> + current_epoch = tcur;
> + recovery_epoch = trec;
> + xlog(D_GENERAL, "%s: current_epoch=%lu recovery_epoch=%lu",
> + __func__, current_epoch, recovery_epoch);
> +
> +out:
> + sqlite3_free(err);
> + return ret;
> +rollback:
> + ret2 = sqlite3_exec(dbh, "ROLLBACK TRANSACTION;", NULL, NULL, &err);
> + if (ret2 != SQLITE_OK)
> + xlog(L_ERROR, "Unable to rollback transaction: %s", err);
> + goto out;
> +}
> +
> +int
> +sqlite_grace_done(void)
> +{
> + int ret, ret2;
> + char *err;
> +
> + /* begin transaction */
> + ret = sqlite3_exec(dbh, "BEGIN EXCLUSIVE TRANSACTION;", NULL, NULL,
> + &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to begin transaction: %s", err);
> + goto rollback;
> + }
> +
> + ret = sqlite3_exec(dbh, "UPDATE grace SET recovery = \"0\";",
> + NULL, NULL, &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to clear recovery epoch: %s", err);
> + goto rollback;
> + }
> +
> + ret = snprintf(buf, sizeof(buf), "DROP TABLE \"rec-%016lx\";",
> + recovery_epoch);
> + if (ret < 0) {
> + xlog(L_ERROR, "sprintf failed!");
> + goto rollback;
> + } else if ((size_t)ret >= sizeof(buf)) {
> + xlog(L_ERROR, "sprintf output too long! (%d chars)", ret);
> + ret = -EINVAL;
> + goto rollback;
> + }
> +
> + ret = sqlite3_exec(dbh, (const char *)buf, NULL, NULL, &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to drop table for recovery epoch: %s",
> + err);
> + goto rollback;
> + }
> +
> + ret = sqlite3_exec(dbh, "COMMIT TRANSACTION;", NULL, NULL, &err);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "Unable to commit transaction: %s", err);
> + goto rollback;
> + }
> +
> + recovery_epoch = 0;
> + xlog(D_GENERAL, "%s: current_epoch=%lu recovery_epoch=%lu",
> + __func__, current_epoch, recovery_epoch);
> +
> +out:
> + sqlite3_free(err);
> + return ret;
> +rollback:
> + ret2 = sqlite3_exec(dbh, "ROLLBACK TRANSACTION;", NULL, NULL, &err);
> + if (ret2 != SQLITE_OK)
> + xlog(L_ERROR, "Unable to rollback transaction: %s", err);
> + goto out;
> +}
> +
> +
> +int
> +sqlite_iterate_recovery(int (*cb)(struct cld_client *clnt), struct cld_client *clnt)
> +{
> + int ret;
> + sqlite3_stmt *stmt = NULL;
> + struct cld_msg *cmsg = &clnt->cl_msg;
> +
> + if (recovery_epoch == 0) {
> + xlog(D_GENERAL, "%s: not in grace!", __func__);
> + return -EINVAL;
> + }
> +
> + ret = snprintf(buf, sizeof(buf), "SELECT * FROM \"rec-%016lx\";",
> + recovery_epoch);
> + if (ret < 0) {
> + xlog(L_ERROR, "sprintf failed!");
> + return ret;
> + } else if ((size_t)ret >= sizeof(buf)) {
> + xlog(L_ERROR, "sprintf output too long! (%d chars)", ret);
> + return -EINVAL;
> + }
> +
> + ret = sqlite3_prepare_v2(dbh, buf, -1, &stmt, NULL);
> + if (ret != SQLITE_OK) {
> + xlog(L_ERROR, "%s: select statement prepare failed: %s",
> + __func__, sqlite3_errmsg(dbh));
> + return ret;
> + }
> +
> + while ((ret = sqlite3_step(stmt)) == SQLITE_ROW) {
> + memcpy(&cmsg->cm_u.cm_name.cn_id, sqlite3_column_blob(stmt, 0),
> + NFS4_OPAQUE_LIMIT);
> + cmsg->cm_u.cm_name.cn_len = sqlite3_column_bytes(stmt, 0);
> + cb(clnt);
> + }
> + if (ret == SQLITE_DONE)
> + ret = 0;
> + sqlite3_finalize(stmt);
> + return ret;
> +}
> diff --git a/utils/nfsdcld/sqlite.h b/utils/nfsdcld/sqlite.h
> index 06e7c04..5c56f75 100644
> --- a/utils/nfsdcld/sqlite.h
> +++ b/utils/nfsdcld/sqlite.h
> @@ -20,13 +20,16 @@
> #ifndef _SQLITE_H_
> #define _SQLITE_H_
>
> +struct cld_client;
> +
> int sqlite_prepare_dbh(const char *topdir);
> -int sqlite_insert_client(const unsigned char *clname, const size_t namelen,
> - const bool has_session, const bool zerotime);
> +int sqlite_insert_client(const unsigned char *clname, const size_t namelen);
> int sqlite_remove_client(const unsigned char *clname, const size_t namelen);
> -int sqlite_check_client(const unsigned char *clname, const size_t namelen,
> - const bool has_session);
> +int sqlite_check_client(const unsigned char *clname, const size_t namelen);
> int sqlite_remove_unreclaimed(const time_t grace_start);
> int sqlite_query_reclaiming(const time_t grace_start);
> +int sqlite_grace_start(void);
> +int sqlite_grace_done(void);
> +int sqlite_iterate_recovery(int (*cb)(struct cld_client *clnt), struct cld_client *clnt);
>
> #endif /* _SQLITE_H */

--
Jeff Layton <jlayton@kernel.org>