tdb2: set owner for locks

The last step before sharing struct tdb_file is to add a field to
identify which tdb context is holding each lock, so we can fail when
they conflict.

diff --git a/ccan/tdb2/lock.c b/ccan/tdb2/lock.c
index 8e73c253cb5ba4eac0ba9cc3c54fbe62ecbc9132..82fcdf17d1e6dfd0126d17232826cc53391329ee 100644 (file)
--- a/ccan/tdb2/lock.c
+++ b/ccan/tdb2/lock.c
@@ -29,6 +29,17 @@
 #include <assert.h>
 #include <ccan/build_assert/build_assert.h>
 
 #include <assert.h>
 #include <ccan/build_assert/build_assert.h>
 

+/* If we were threaded, we could wait for unlock, but we're not, so fail. */
+static bool owner_conflict(struct tdb_context *tdb, struct tdb_lock *lock)
+{
+       if (lock->owner != tdb) {
+               tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
+                          "Lock already owned by another opener");
+               return true;
+       }
+       return false;
+}
+

 static int fcntl_lock(struct tdb_context *tdb,
                      int rw, off_t off, off_t len, bool waitflag)
 {
 static int fcntl_lock(struct tdb_context *tdb,
                      int rw, off_t off, off_t len, bool waitflag)
 {


@@ -236,12 +247,15 @@ enum TDB_ERROR tdb_allrecord_upgrade(struct tdb_context *tdb)
                          "tdb_allrecord_upgrade failed");
 }
 
                          "tdb_allrecord_upgrade failed");
 }
 

-static struct tdb_lock *find_nestlock(struct tdb_context *tdb, tdb_off_t offset)
+static struct tdb_lock *find_nestlock(struct tdb_context *tdb, tdb_off_t offset,
+                                     const struct tdb_context *owner)

 {
        unsigned int i;
 
        for (i=0; i<tdb->file->num_lockrecs; i++) {
                if (tdb->file->lockrecs[i].off == offset) {
 {
        unsigned int i;
 
        for (i=0; i<tdb->file->num_lockrecs; i++) {
                if (tdb->file->lockrecs[i].off == offset) {

+                       if (owner && tdb->file->lockrecs[i].owner != owner)
+                               return NULL;

                        return &tdb->file->lockrecs[i];
                }
        }
                        return &tdb->file->lockrecs[i];
                }
        }


@@ -290,8 +304,11 @@ static enum TDB_ERROR tdb_nest_lock(struct tdb_context *tdb,
 
        add_stat(tdb, locks, 1);
 
 
        add_stat(tdb, locks, 1);
 

-       new_lck = find_nestlock(tdb, offset);
+       new_lck = find_nestlock(tdb, offset, NULL);

        if (new_lck) {
        if (new_lck) {

+               if (owner_conflict(tdb, new_lck))
+                       return -1;
+

                if (new_lck->ltype == F_RDLCK && ltype == F_WRLCK) {
                        return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
                                          "tdb_nest_lock:"
                if (new_lck->ltype == F_RDLCK && ltype == F_WRLCK) {
                        return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
                                          "tdb_nest_lock:"


@@ -348,6 +365,7 @@ static enum TDB_ERROR tdb_nest_lock(struct tdb_context *tdb,
                }
        }
 
                }
        }
 

+       tdb->file->lockrecs[tdb->file->num_lockrecs].owner = tdb;

        tdb->file->lockrecs[tdb->file->num_lockrecs].off = offset;
        tdb->file->lockrecs[tdb->file->num_lockrecs].count = 1;
        tdb->file->lockrecs[tdb->file->num_lockrecs].ltype = ltype;
        tdb->file->lockrecs[tdb->file->num_lockrecs].off = offset;
        tdb->file->lockrecs[tdb->file->num_lockrecs].count = 1;
        tdb->file->lockrecs[tdb->file->num_lockrecs].ltype = ltype;


@@ -365,7 +383,7 @@ static enum TDB_ERROR tdb_nest_unlock(struct tdb_context *tdb,
        if (tdb->flags & TDB_NOLOCK)
                return TDB_SUCCESS;
 
        if (tdb->flags & TDB_NOLOCK)
                return TDB_SUCCESS;
 

-       lck = find_nestlock(tdb, off);
+       lck = find_nestlock(tdb, off, tdb);

        if ((lck == NULL) || (lck->count == 0)) {
                return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
                                  "tdb_nest_unlock: no lock for %zu",
        if ((lck == NULL) || (lck->count == 0)) {
                return tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
                                  "tdb_nest_unlock: no lock for %zu",


@@ -508,6 +526,7 @@ again:
                return ecode;
        }
 
                return ecode;
        }
 

+       tdb->file->allrecord_lock.owner = tdb;

        tdb->file->allrecord_lock.count = 1;
        /* If it's upgradable, it's actually exclusive so we can treat
         * it as a write lock. */
        tdb->file->allrecord_lock.count = 1;
        /* If it's upgradable, it's actually exclusive so we can treat
         * it as a write lock. */


@@ -545,7 +564,7 @@ void tdb_unlock_open(struct tdb_context *tdb)
 bool tdb_has_open_lock(struct tdb_context *tdb)
 {
        return !(tdb->flags & TDB_NOLOCK)
 bool tdb_has_open_lock(struct tdb_context *tdb)
 {
        return !(tdb->flags & TDB_NOLOCK)

-               && find_nestlock(tdb, TDB_OPEN_LOCK) != NULL;
+               && find_nestlock(tdb, TDB_OPEN_LOCK, tdb) != NULL;

 }
 
 enum TDB_ERROR tdb_lock_expand(struct tdb_context *tdb, int ltype)
 }
 
 enum TDB_ERROR tdb_lock_expand(struct tdb_context *tdb, int ltype)


@@ -569,6 +588,12 @@ void tdb_allrecord_unlock(struct tdb_context *tdb, int ltype)
                return;
        }
 
                return;
        }
 

+       if (tdb->file->allrecord_lock.owner != tdb) {
+               tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_USE_ERROR,
+                          "tdb_allrecord_unlock: not locked by us!");
+               return;
+       }
+

        /* Upgradable locks are marked as write locks. */
        if (tdb->file->allrecord_lock.ltype != ltype
            && (!tdb->file->allrecord_lock.off || ltype != F_RDLCK)) {
        /* Upgradable locks are marked as write locks. */
        if (tdb->file->allrecord_lock.ltype != ltype
            && (!tdb->file->allrecord_lock.off || ltype != F_RDLCK)) {


@@ -592,7 +617,7 @@ void tdb_allrecord_unlock(struct tdb_context *tdb, int ltype)
 
 bool tdb_has_expansion_lock(struct tdb_context *tdb)
 {
 
 bool tdb_has_expansion_lock(struct tdb_context *tdb)
 {

-       return find_nestlock(tdb, TDB_EXPANSION_LOCK) != NULL;
+       return find_nestlock(tdb, TDB_EXPANSION_LOCK, tdb) != NULL;

 }
 
 bool tdb_has_hash_locks(struct tdb_context *tdb)
 }
 
 bool tdb_has_hash_locks(struct tdb_context *tdb)


@@ -729,3 +754,22 @@ void tdb_unlock_free_bucket(struct tdb_context *tdb, tdb_off_t b_off)
 
        tdb_nest_unlock(tdb, free_lock_off(b_off), F_WRLCK);
 }
 
        tdb_nest_unlock(tdb, free_lock_off(b_off), F_WRLCK);
 }

+
+void tdb_unlock_all(struct tdb_context *tdb)
+{
+       unsigned int i;
+
+       while (tdb->file->allrecord_lock.count
+              && tdb->file->allrecord_lock.owner == tdb) {
+               tdb_allrecord_unlock(tdb, tdb->file->allrecord_lock.ltype);
+       }
+
+       for (i=0; i<tdb->file->num_lockrecs; i++) {
+               if (tdb->file->lockrecs[i].owner == tdb) {
+                       tdb_nest_unlock(tdb,
+                                       tdb->file->lockrecs[i].off,
+                                       tdb->file->lockrecs[i].ltype);
+                       i--;
+               }
+       }
+}

diff --git a/ccan/tdb2/open.c b/ccan/tdb2/open.c
index b72d783b4f34d4e16b589c6b47275a7b7285987b..56f606664519ba286b0ffc1443d200480182fee7 100644 (file)
--- a/ccan/tdb2/open.c
+++ b/ccan/tdb2/open.c
@@ -448,6 +448,7 @@ struct tdb_context *tdb_open(const char *name, int tdb_flags,
 #endif
        free((char *)tdb->name);
        if (tdb->file) {
 #endif
        free((char *)tdb->name);
        if (tdb->file) {

+               tdb_unlock_all(tdb);

                if (tdb->file->map_ptr) {
                        if (tdb->flags & TDB_INTERNAL) {
                                free(tdb->file->map_ptr);
                if (tdb->file->map_ptr) {
                        if (tdb->flags & TDB_INTERNAL) {
                                free(tdb->file->map_ptr);

diff --git a/ccan/tdb2/private.h b/ccan/tdb2/private.h
index d1f12b5531ff6843a8f94bd8182cd7156709e765..b709ee95b97375845a06814998b37a5b711bbfb1 100644 (file)
--- a/ccan/tdb2/private.h
+++ b/ccan/tdb2/private.h
@@ -301,6 +301,7 @@ enum tdb_lock_flags {
 };
 
 struct tdb_lock {
 };
 
 struct tdb_lock {

+       struct tdb_context *owner;

        uint32_t off;
        uint32_t count;
        uint32_t ltype;
        uint32_t off;
        uint32_t count;
        uint32_t ltype;


@@ -536,6 +537,9 @@ enum TDB_ERROR tdb_unlock_hashes(struct tdb_context *tdb,
                                 tdb_off_t hash_lock,
                                 tdb_len_t hash_range, int ltype);
 
                                 tdb_off_t hash_lock,
                                 tdb_len_t hash_range, int ltype);
 

+/* For closing the file. */
+void tdb_unlock_all(struct tdb_context *tdb);
+

 /* Lock/unlock a particular free bucket. */
 enum TDB_ERROR tdb_lock_free_bucket(struct tdb_context *tdb, tdb_off_t b_off,
                                    enum tdb_lock_flags waitflag);
 /* Lock/unlock a particular free bucket. */
 enum TDB_ERROR tdb_lock_free_bucket(struct tdb_context *tdb, tdb_off_t b_off,
                                    enum tdb_lock_flags waitflag);