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author | Jelmer Vernooij <jelmer@samba.org> | 2008-02-09 20:06:54 +0100 |
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committer | Jelmer Vernooij <jelmer@samba.org> | 2008-02-09 20:06:54 +0100 |
commit | ec106a14216ee034b7e04c177c89703e63dfd107 (patch) | |
tree | 59c56cd663ee3dc03d0ce63bf4405ee87c14834a /source4/lib/tdb/common/tdb.c | |
parent | 4075a2ba982ea56ff925e0a33839f0760fd71911 (diff) | |
parent | 1a2544a24c064e9eecb973439ccd0e7126e06e77 (diff) | |
download | samba-ec106a14216ee034b7e04c177c89703e63dfd107.tar.gz samba-ec106a14216ee034b7e04c177c89703e63dfd107.tar.bz2 samba-ec106a14216ee034b7e04c177c89703e63dfd107.zip |
Merge branch 'v4-0-trivial' into v4-0-python
(This used to be commit b874f07175ae38a041f53f0e4ac6a4050dcefeae)
Diffstat (limited to 'source4/lib/tdb/common/tdb.c')
-rw-r--r-- | source4/lib/tdb/common/tdb.c | 83 |
1 files changed, 70 insertions, 13 deletions
diff --git a/source4/lib/tdb/common/tdb.c b/source4/lib/tdb/common/tdb.c index ea5d9ccc60..767452c9b3 100644 --- a/source4/lib/tdb/common/tdb.c +++ b/source4/lib/tdb/common/tdb.c @@ -687,20 +687,66 @@ 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) { int i; tdb_off_t offset = 0; ssize_t data_len; + tdb_off_t recovery_head; + tdb_len_t recovery_size = 0; if (tdb_lockall(tdb) != 0) { return -1; } + /* see if the tdb has a recovery area, and remember its size + if so. We don't want to lose this as otherwise each + tdb_wipe_all() in a transaction will increase the size of + the tdb by the size of the recovery area */ + if (tdb_ofs_read(tdb, TDB_RECOVERY_HEAD, &recovery_head) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_wipe_all: failed to read recovery head\n")); + goto failed; + } + + if (recovery_head != 0) { + struct list_struct rec; + if (tdb->methods->tdb_read(tdb, recovery_head, &rec, sizeof(rec), DOCONV()) == -1) { + TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_wipe_all: failed to read recovery record\n")); + return -1; + } + recovery_size = rec.rec_len + sizeof(rec); + } + /* wipe the hashes */ for (i=0;i<tdb->header.hash_size;i++) { if (tdb_ofs_write(tdb, TDB_HASH_TOP(i), &offset) == -1) { @@ -715,19 +761,30 @@ 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 > 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; + } + } 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; + } + /* 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; } } |