diff options
| -rw-r--r-- | source4/lib/tdb/common/tdb.c | 80 |
1 files changed, 47 insertions, 33 deletions
diff --git a/source4/lib/tdb/common/tdb.c b/source4/lib/tdb/common/tdb.c index a25c3e7aca..767452c9b3 100644 --- a/source4/lib/tdb/common/tdb.c +++ b/source4/lib/tdb/common/tdb.c @@ -687,9 +687,35 @@ void tdb_enable_seqnum(struct tdb_context *tdb) /* + add a region of the file to the freelist. Length is the size of the region in bytes, + which includes the free list header that needs to be added + */ +static int tdb_free_region(struct tdb_context *tdb, tdb_off_t offset, ssize_t length) +{ + struct list_struct rec; + if (length <= sizeof(rec)) { + /* the region is not worth adding */ + return 0; + } + if (length + offset > tdb->map_size) { + TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_free_region: adding region beyond end of file\n")); + return -1; + } + memset(&rec,'\0',sizeof(rec)); + rec.rec_len = length - sizeof(rec); + if (tdb_free(tdb, offset, &rec) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_free_region: failed to add free record\n")); + return -1; + } + return 0; +} + +/* wipe the entire database, deleting all records. This can be done very fast by using a global lock. The entire data portion of the file becomes a single entry in the freelist. + + This code carefully steps around the recovery area, leaving it alone */ int tdb_wipe_all(struct tdb_context *tdb) { @@ -735,43 +761,31 @@ int tdb_wipe_all(struct tdb_context *tdb) goto failed; } - if (tdb_ofs_write(tdb, TDB_RECOVERY_HEAD, &offset) == -1) { - TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_wipe_all: failed to write recovery head\n")); - goto failed; - } - - /* add all the rest of the file to the freelist */ - data_len = (tdb->map_size - TDB_DATA_START(tdb->header.hash_size)) - sizeof(struct list_struct); - if (data_len < recovery_size+sizeof(tdb_off_t)) { - recovery_size = 0; - } else { - data_len -= recovery_size; - } - if (data_len > 0) { - struct list_struct rec; - memset(&rec,'\0',sizeof(rec)); - rec.rec_len = data_len; - if (tdb_free(tdb, TDB_DATA_START(tdb->header.hash_size), &rec) == -1) { - TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_wipe_all: failed to add free record\n")); + /* add all the rest of the file to the freelist, possibly leaving a gap + for the recovery area */ + if (recovery_size == 0) { + /* the simple case - the whole file can be used as a freelist */ + data_len = (tdb->map_size - TDB_DATA_START(tdb->header.hash_size)); + if (tdb_free_region(tdb, TDB_DATA_START(tdb->header.hash_size), data_len) != 0) { goto failed; } - } - - /* possibly add the recovery record */ - if (recovery_size != 0) { - struct list_struct rec; - - recovery_head = tdb->map_size - recovery_size; - - ZERO_STRUCT(rec); - rec.rec_len = recovery_size - sizeof(rec); - if (tdb_rec_write(tdb, recovery_head, &rec) != 0) { - TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_wipe_all: failed to add recovery record\n")); + } else { + /* we need to add two freelist entries - one on either + side of the recovery area + + Note that we cannot shift the recovery area during + this operation. Only the transaction.c code may + move the recovery area or we risk subtle data + corruption + */ + data_len = (recovery_head - TDB_DATA_START(tdb->header.hash_size)); + if (tdb_free_region(tdb, TDB_DATA_START(tdb->header.hash_size), data_len) != 0) { goto failed; } - if (tdb_ofs_write(tdb, TDB_RECOVERY_HEAD, &recovery_head) == -1) { - TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_wipe_all: failed to write recovery head\n")); - goto failed; + /* and the 2nd free list entry after the recovery area - if any */ + data_len = tdb->map_size - (recovery_head+recovery_size); + if (tdb_free_region(tdb, recovery_head+recovery_size, data_len) != 0) { + goto failed; } } |