tdb: use tdb_nest_lock() for active lock.

Rather than a boutique lock and a separate nest count, use our
newly-generic nested lock tracking for the active lock.

Note that the tdb_have_extra_locks() and tdb_release_extra_locks()
functions have to skip over this lock now it is tracked.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/ccan/tdb/lock.c b/ccan/tdb/lock.c
index 6f5799a8198f13dd06851aae03869c635035200e..19b92d9ae09c63152b87d10062b1363a8c063516 100644 (file)
--- a/ccan/tdb/lock.c
+++ b/ccan/tdb/lock.c
@@ -675,6 +675,11 @@ bool tdb_have_extra_locks(struct tdb_context *tdb)
                return true;
        }
 
                return true;
        }
 

+       /* We always hold the active lock if CLEAR_IF_FIRST. */
+       if (find_nestlock(tdb, ACTIVE_LOCK)) {
+               extra--;
+       }
+

        /* In a transaction, we expect to hold the transaction lock */
        if (tdb->transaction && find_nestlock(tdb, TRANSACTION_LOCK)) {
                extra--;
        /* In a transaction, we expect to hold the transaction lock */
        if (tdb->transaction && find_nestlock(tdb, TRANSACTION_LOCK)) {
                extra--;


@@ -698,8 +703,11 @@ void tdb_release_extra_locks(struct tdb_context *tdb)
        for (i=0;i<tdb->num_lockrecs;i++) {
                struct tdb_lock_type *lck = &tdb->lockrecs[i];
 
        for (i=0;i<tdb->num_lockrecs;i++) {
                struct tdb_lock_type *lck = &tdb->lockrecs[i];
 

+               /* Don't release transaction or active locks! */

                if (tdb->transaction && lck->off == TRANSACTION_LOCK) {
                        tdb->lockrecs[extra++] = *lck;
                if (tdb->transaction && lck->off == TRANSACTION_LOCK) {
                        tdb->lockrecs[extra++] = *lck;

+               } else if (lck->off == ACTIVE_LOCK) {
+                       tdb->lockrecs[extra++] = *lck;

                } else {
                        tdb_brunlock(tdb, lck->ltype, lck->off, 1);
                }
                } else {
                        tdb_brunlock(tdb, lck->ltype, lck->off, 1);
                }

diff --git a/ccan/tdb/open.c b/ccan/tdb/open.c
index 54a8fe57ad11a460471785dbf370f7ae1f4a9b93..bfa26dec58fd256db124fcd18ca9c50598ea4fe7 100644 (file)
--- a/ccan/tdb/open.c
+++ b/ccan/tdb/open.c
@@ -249,7 +249,7 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
        /* we need to zero database if we are the only one with it open */
        if ((tdb_flags & TDB_CLEAR_IF_FIRST) &&
            (!tdb->read_only) &&
        /* we need to zero database if we are the only one with it open */
        if ((tdb_flags & TDB_CLEAR_IF_FIRST) &&
            (!tdb->read_only) &&

-           (locked = (tdb->methods->brlock(tdb, F_WRLCK, ACTIVE_LOCK, 1, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE) == 0))) {
+           (locked = (tdb_nest_lock(tdb, ACTIVE_LOCK, F_WRLCK, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE) == 0))) {

                open_flags |= O_CREAT;
                if (ftruncate(tdb->fd, 0) == -1) {
                        TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "
                open_flags |= O_CREAT;
                if (ftruncate(tdb->fd, 0) == -1) {
                        TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "


@@ -312,7 +312,7 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
        tdb->inode = st.st_ino;
        tdb_mmap(tdb);
        if (locked) {
        tdb->inode = st.st_ino;
        tdb_mmap(tdb);
        if (locked) {

-               if (tdb->methods->brunlock(tdb, F_WRLCK, ACTIVE_LOCK, 1) == -1) {
+               if (tdb_nest_unlock(tdb, ACTIVE_LOCK, F_WRLCK, false) == -1) {

                        TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
                                 "failed to take ACTIVE_LOCK on %s: %s\n",
                                 name, strerror(errno)));
                        TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "
                                 "failed to take ACTIVE_LOCK on %s: %s\n",
                                 name, strerror(errno)));


@@ -327,8 +327,9 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
 
        if (tdb_flags & TDB_CLEAR_IF_FIRST) {
                /* leave this lock in place to indicate it's in use */
 
        if (tdb_flags & TDB_CLEAR_IF_FIRST) {
                /* leave this lock in place to indicate it's in use */

-               if (tdb->methods->brlock(tdb, F_RDLCK, ACTIVE_LOCK, 1, TDB_LOCK_WAIT) == -1)
+               if (tdb_nest_lock(tdb, ACTIVE_LOCK, F_RDLCK, TDB_LOCK_WAIT) == -1) {

                        goto fail;
                        goto fail;

+               }

        }
 
        /* if needed, run recovery */
        }
 
        /* if needed, run recovery */


@@ -382,6 +383,7 @@ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,
        if (tdb->fd != -1)
                if (close(tdb->fd) != 0)
                        TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to close tdb->fd on error!\n"));
        if (tdb->fd != -1)
                if (close(tdb->fd) != 0)
                        TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to close tdb->fd on error!\n"));

+       SAFE_FREE(tdb->lockrecs);

        SAFE_FREE(tdb);
        errno = save_errno;
        return NULL;
        SAFE_FREE(tdb);
        errno = save_errno;
        return NULL;


@@ -493,8 +495,11 @@ static int tdb_reopen_internal(struct tdb_context *tdb, bool active_lock)
        }
        tdb_mmap(tdb);
 
        }
        tdb_mmap(tdb);
 

-       if (active_lock &&
-           (tdb->methods->brlock(tdb, F_RDLCK, ACTIVE_LOCK, 1, TDB_LOCK_WAIT) == -1)) {
+       /* We may still think we hold the active lock. */
+       tdb->num_lockrecs = 0;
+       SAFE_FREE(tdb->lockrecs);
+
+       if (active_lock && tdb_nest_lock(tdb, ACTIVE_LOCK, F_RDLCK, TDB_LOCK_WAIT) == -1) {

                TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: failed to obtain active lock\n"));
                goto fail;
        }
                TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: failed to obtain active lock\n"));
                goto fail;
        }

diff --git a/ccan/tdb/tdb_private.h b/ccan/tdb/tdb_private.h
index 4214b261bc60b605bfa9babbf1162401ee012d51..fe68d5116303630259fc9c31379035d77a8d046f 100644 (file)
--- a/ccan/tdb/tdb_private.h
+++ b/ccan/tdb/tdb_private.h
@@ -259,6 +259,7 @@ int tdb_nest_lock(struct tdb_context *tdb, uint32_t offset, int ltype,
                  enum tdb_lock_flags flags);
 int tdb_nest_unlock(struct tdb_context *tdb, uint32_t offset, int ltype,
                    bool mark_lock);
                  enum tdb_lock_flags flags);
 int tdb_nest_unlock(struct tdb_context *tdb, uint32_t offset, int ltype,
                    bool mark_lock);

+bool tdb_have_locks(struct tdb_context *tdb);

 int tdb_unlock(struct tdb_context *tdb, int list, int ltype);
 int tdb_brlock(struct tdb_context *tdb,
               int rw_type, tdb_off_t offset, size_t len,
 int tdb_unlock(struct tdb_context *tdb, int list, int ltype);
 int tdb_brlock(struct tdb_context *tdb,
               int rw_type, tdb_off_t offset, size_t len,