diff options
Diffstat (limited to 'source3')
| -rw-r--r-- | source3/lib/tdb/common/freelist.c | 85 | ||||
| -rw-r--r-- | source3/lib/tdb/common/tdb_private.h | 1 |
2 files changed, 43 insertions, 43 deletions
diff --git a/source3/lib/tdb/common/freelist.c b/source3/lib/tdb/common/freelist.c index c086c151fa..2f2a4c379b 100644 --- a/source3/lib/tdb/common/freelist.c +++ b/source3/lib/tdb/common/freelist.c @@ -208,62 +208,61 @@ update: } + /* the core of tdb_allocate - called when we have decided which free list entry to use + + Note that we try to allocate by grabbing data from the end of an existing record, + not the beginning. This is so the left merge in a free is more likely to be + able to free up the record without fragmentation */ -static tdb_off_t tdb_allocate_ofs(struct tdb_context *tdb, tdb_len_t length, tdb_off_t rec_ptr, - struct list_struct *rec, tdb_off_t last_ptr) +static tdb_off_t tdb_allocate_ofs(struct tdb_context *tdb, + tdb_len_t length, tdb_off_t rec_ptr, + struct list_struct *rec, tdb_off_t last_ptr) { - struct list_struct newrec; - tdb_off_t newrec_ptr; +#define MIN_REC_SIZE (sizeof(struct list_struct) + sizeof(tdb_off_t) + 8) - memset(&newrec, '\0', sizeof(newrec)); + if (rec->rec_len < length + MIN_REC_SIZE) { + /* we have to grab the whole record */ - /* found it - now possibly split it up */ - if (rec->rec_len > length + MIN_REC_SIZE) { - /* Length of left piece */ - length = TDB_ALIGN(length, TDB_ALIGNMENT); - - /* Right piece to go on free list */ - newrec.rec_len = rec->rec_len - (sizeof(*rec) + length); - newrec_ptr = rec_ptr + sizeof(*rec) + length; - - /* And left record is shortened */ - rec->rec_len = length; - } else { - newrec_ptr = 0; + /* unlink it from the previous record */ + if (tdb_ofs_write(tdb, last_ptr, &rec->next) == -1) { + return 0; + } + + /* mark it not free */ + rec->magic = TDB_MAGIC; + if (tdb_rec_write(tdb, rec_ptr, rec) == -1) { + return 0; + } + return rec_ptr; + } + + /* we're going to just shorten the existing record */ + rec->rec_len -= (length + sizeof(*rec)); + if (tdb_rec_write(tdb, rec_ptr, rec) == -1) { + return 0; } - - /* Remove allocated record from the free list */ - if (tdb_ofs_write(tdb, last_ptr, &rec->next) == -1) { + if (update_tailer(tdb, rec_ptr, rec) == -1) { return 0; } - - /* Update header: do this before we drop alloc - lock, otherwise tdb_free() might try to - merge with us, thinking we're free. - (Thanks Jeremy Allison). */ + + /* and setup the new record */ + rec_ptr += sizeof(*rec) + rec->rec_len; + + memset(rec, '\0', sizeof(*rec)); + rec->rec_len = length; rec->magic = TDB_MAGIC; + if (tdb_rec_write(tdb, rec_ptr, rec) == -1) { return 0; } - - /* Did we create new block? */ - if (newrec_ptr) { - /* Update allocated record tailer (we - shortened it). */ - if (update_tailer(tdb, rec_ptr, rec) == -1) { - return 0; - } - - /* Free new record */ - if (tdb_free(tdb, newrec_ptr, &newrec) == -1) { - return 0; - } + + if (update_tailer(tdb, rec_ptr, rec) == -1) { + return 0; } - - /* all done - return the new record offset */ + return rec_ptr; } @@ -287,6 +286,7 @@ tdb_off_t tdb_allocate(struct tdb_context *tdb, tdb_len_t length, struct list_st /* Extra bytes required for tailer */ length += sizeof(tdb_off_t); + length = TDB_ALIGN(length, TDB_ALIGNMENT); again: last_ptr = FREELIST_TOP; @@ -343,7 +343,8 @@ tdb_off_t tdb_allocate(struct tdb_context *tdb, tdb_len_t length, struct list_st goto fail; } - newrec_ptr = tdb_allocate_ofs(tdb, length, bestfit.rec_ptr, rec, bestfit.last_ptr); + newrec_ptr = tdb_allocate_ofs(tdb, length, bestfit.rec_ptr, + rec, bestfit.last_ptr); tdb_unlock(tdb, -1, F_WRLCK); return newrec_ptr; } diff --git a/source3/lib/tdb/common/tdb_private.h b/source3/lib/tdb/common/tdb_private.h index dd69903015..ffac89ff0e 100644 --- a/source3/lib/tdb/common/tdb_private.h +++ b/source3/lib/tdb/common/tdb_private.h @@ -49,7 +49,6 @@ typedef uint32_t tdb_off_t; #define TDB_DEAD_MAGIC (0xFEE1DEAD) #define TDB_RECOVERY_MAGIC (0xf53bc0e7U) #define TDB_ALIGNMENT 4 -#define MIN_REC_SIZE (2*sizeof(struct list_struct) + TDB_ALIGNMENT) #define DEFAULT_HASH_SIZE 131 #define FREELIST_TOP (sizeof(struct tdb_header)) #define TDB_ALIGN(x,a) (((x) + (a)-1) & ~((a)-1)) |