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authorJelmer Vernooij <jelmer@samba.org>2008-02-09 20:06:54 +0100
committerJelmer Vernooij <jelmer@samba.org>2008-02-09 20:06:54 +0100
commitec106a14216ee034b7e04c177c89703e63dfd107 (patch)
tree59c56cd663ee3dc03d0ce63bf4405ee87c14834a /source4/lib/tdb/common/tdb.c
parent4075a2ba982ea56ff925e0a33839f0760fd71911 (diff)
parent1a2544a24c064e9eecb973439ccd0e7126e06e77 (diff)
downloadsamba-ec106a14216ee034b7e04c177c89703e63dfd107.tar.gz
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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.c83
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;
}
}