/*
* Sherlock Library -- Object Buckets
*
- * (c) 2001 Martin Mares <mj@ucw.cz>
+ * (c) 2001--2003 Martin Mares <mj@ucw.cz>
*
- * Warning: Touches internals of the fb-file module!
+ * This software may be freely distributed and used according to the terms
+ * of the GNU Lesser General Public License.
*/
#include "lib/lib.h"
#include "lib/bucket.h"
#include "lib/fastbuf.h"
+#include "lib/lfs.h"
+#include "lib/conf.h"
#include <string.h>
+#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/file.h>
static int obuck_fd;
+static unsigned int obuck_remains, obuck_check_pad;
static struct fastbuf *obuck_fb;
static struct obuck_header obuck_hdr;
-static sh_off_t start_of_this, start_of_next;
-static char *obuck_name = "db/objects"; /* FIXME */
+static sh_off_t bucket_start, bucket_current;
-void
-obuck_init(int writeable)
-{
- obuck_fb = bopen(obuck_name, (writeable ? O_RDWR | O_CREAT : O_RDONLY), 65536);
- obuck_fd = obuck_fb->fd;
-}
+/*** Configuration ***/
-void
-obuck_cleanup(void)
+byte *obuck_name = "not/configured";
+static uns obuck_io_buflen = 65536;
+static int obuck_shake_buflen = 1048576;
+static uns obuck_slurp_buflen = 65536;
+
+static struct cfitem obuck_config[] = {
+ { "Buckets", CT_SECTION, NULL },
+ { "BucketFile", CT_STRING, &obuck_name },
+ { "BufSize", CT_INT, &obuck_io_buflen },
+ { "ShakeBufSize", CT_INT, &obuck_shake_buflen },
+ { "SlurpBufSize", CT_INT, &obuck_slurp_buflen },
+ { NULL, CT_STOP, NULL }
+};
+
+static void CONSTRUCTOR obuck_init_config(void)
{
- bclose(obuck_fb);
+ cf_register(obuck_config);
}
+/*** Internal operations ***/
+
static void
obuck_broken(char *msg)
{
- die("Object pool corrupted: %s", msg); /* FIXME */
+ die("Object pool corrupted: %s (pos=%Lx)", msg, (long long) bucket_start);
}
+/*
+ * Unfortunately we cannot use flock() here since it happily permits
+ * locking a shared fd (e.g., after fork()) multiple times. The fcntl
+ * locks are very ugly and they don't support 64-bit offsets, but we
+ * can work around the problem by always locking the first header
+ * in the file.
+ */
+
static inline void
+obuck_do_lock(int type)
+{
+ struct flock fl;
+
+ fl.l_type = type;
+ fl.l_whence = SEEK_SET;
+ fl.l_start = 0;
+ fl.l_len = sizeof(struct obuck_header);
+ if (fcntl(obuck_fd, F_SETLKW, &fl) < 0)
+ die("fcntl lock: %m");
+}
+
+inline void
obuck_lock_read(void)
{
- flock(obuck_fd, LOCK_SH);
+ obuck_do_lock(F_RDLCK);
}
-static inline void
+inline void
obuck_lock_write(void)
{
- flock(obuck_fd, LOCK_EX);
+ obuck_do_lock(F_WRLCK);
}
-static inline void
+inline void
obuck_unlock(void)
{
- flock(obuck_fd, LOCK_UN);
+ obuck_do_lock(F_UNLCK);
+}
+
+/*** FastIO emulation ***/
+
+/* We need to use pread/pwrite since we work on fd's shared between processes */
+
+static int
+obuck_fb_refill(struct fastbuf *f)
+{
+ unsigned limit = (obuck_io_buflen < obuck_remains) ? obuck_io_buflen : obuck_remains;
+ unsigned size = (limit == obuck_remains) ? (limit+obuck_check_pad+4) : limit;
+ int l;
+
+ if (!limit)
+ return 0;
+ l = sh_pread(obuck_fd, f->buffer, size, bucket_current);
+ if (l < 0)
+ die("Error reading bucket: %m");
+ if ((unsigned) l != size)
+ obuck_broken("Short read");
+ f->bptr = f->buffer;
+ f->bstop = f->buffer + limit;
+ bucket_current += limit;
+ f->pos = bucket_current - bucket_start - sizeof(obuck_hdr);
+ obuck_remains -= limit;
+ if (!obuck_remains) /* Should check the trailer */
+ {
+ if (GET_U32(f->buffer + size - 4) != OBUCK_TRAILER)
+ obuck_broken("Missing trailer");
+ }
+ return limit;
}
static void
-obuck_fetch_header(oid_t oid)
+obuck_fb_spout(struct fastbuf *f)
{
- start_of_this = ((sh_off_t) oid) << OBUCK_SHIFT;
- bsetpos(obuck_fb, start_of_this);
- bread(obuck_fb, &obuck_hdr, sizeof(obuck_hdr));
+ int l = f->bptr - f->buffer;
+ char *c = f->buffer;
+
+ while (l)
+ {
+ int z = sh_pwrite(obuck_fd, c, l, bucket_current);
+ if (z <= 0)
+ die("Error writing bucket: %m");
+ bucket_current += z;
+ l -= z;
+ c += z;
+ }
+ f->bptr = f->buffer;
+ f->pos = bucket_current - bucket_start - sizeof(obuck_hdr);
+}
+
+/*** Exported functions ***/
+
+void
+obuck_init(int writeable)
+{
+ struct fastbuf *b;
+ sh_off_t size;
+
+ obuck_fd = sh_open(obuck_name, (writeable ? O_RDWR | O_CREAT : O_RDONLY), 0666);
+ if (obuck_fd < 0)
+ die("Unable to open bucket file %s: %m", obuck_name);
+ obuck_fb = b = xmalloc_zero(sizeof(struct fastbuf) + obuck_io_buflen + OBUCK_ALIGN + 4);
+ b->buffer = (char *)(b+1);
+ b->bptr = b->bstop = b->buffer;
+ b->bufend = b->buffer + obuck_io_buflen;
+ b->name = "bucket";
+ b->refill = obuck_fb_refill;
+ b->spout = obuck_fb_spout;
+ obuck_lock_read();
+ size = sh_seek(obuck_fd, 0, SEEK_END);
+ if (size)
+ {
+ /* If the bucket pool is not empty, check consistency of its end */
+ u32 check;
+ bucket_start = size - 4; /* for error reporting */
+ if (sh_pread(obuck_fd, &check, 4, size-4) != 4 ||
+ check != OBUCK_TRAILER)
+ obuck_broken("Missing trailer of last object");
+ }
+ obuck_unlock();
+}
+
+void
+obuck_cleanup(void)
+{
+ bclose(obuck_fb);
+ close(obuck_fd);
+ xfree(obuck_fb);
+}
+
+void
+obuck_sync(void)
+{
+ bflush(obuck_fb);
+ fsync(obuck_fd);
+}
+
+static void
+obuck_get(oid_t oid)
+{
+ struct fastbuf *b = obuck_fb;
+
+ bucket_start = obuck_get_pos(oid);
+ bflush(b);
+ if (sh_pread(obuck_fd, &obuck_hdr, sizeof(obuck_hdr), bucket_start) != sizeof(obuck_hdr))
+ obuck_broken("Short header read");
+ bucket_current = bucket_start + sizeof(obuck_hdr);
if (obuck_hdr.magic != OBUCK_MAGIC)
obuck_broken("Missing magic number");
if (obuck_hdr.oid == OBUCK_OID_DELETED)
obuck_broken("Invalid backlink");
}
-struct fastbuf *
-obuck_fetch(struct obuck_header *hdrp)
+void
+obuck_find_by_oid(struct obuck_header *hdrp)
{
+ oid_t oid = hdrp->oid;
+
+ ASSERT(oid < OBUCK_OID_FIRST_SPECIAL);
obuck_lock_read();
- obuck_fetch_header(hdrp->oid);
+ obuck_get(oid);
+ obuck_unlock();
memcpy(hdrp, &obuck_hdr, sizeof(obuck_hdr));
- return obuck_fb;
}
-void
-obuck_fetch_abort(struct fastbuf *b UNUSED)
+int
+obuck_find_first(struct obuck_header *hdrp, int full)
{
- obuck_unlock();
+ bucket_start = 0;
+ obuck_hdr.magic = 0;
+ return obuck_find_next(hdrp, full);
+}
+
+int
+obuck_find_next(struct obuck_header *hdrp, int full)
+{
+ int c;
+ struct fastbuf *b = obuck_fb;
+
+ for(;;)
+ {
+ if (obuck_hdr.magic)
+ bucket_start = (bucket_start + sizeof(obuck_hdr) + obuck_hdr.length +
+ 4 + OBUCK_ALIGN - 1) & ~((sh_off_t)(OBUCK_ALIGN - 1));
+ bflush(b);
+ obuck_lock_read();
+ c = sh_pread(obuck_fd, &obuck_hdr, sizeof(obuck_hdr), bucket_start);
+ obuck_unlock();
+ if (!c)
+ return 0;
+ if (c != sizeof(obuck_hdr))
+ obuck_broken("Short header read");
+ bucket_current = bucket_start + sizeof(obuck_hdr);
+ if (obuck_hdr.magic != OBUCK_MAGIC)
+ obuck_broken("Missing magic number");
+ if (obuck_hdr.oid != OBUCK_OID_DELETED || full)
+ {
+ memcpy(hdrp, &obuck_hdr, sizeof(obuck_hdr));
+ return 1;
+ }
+ }
+}
+
+struct fastbuf *
+obuck_fetch(void)
+{
+ obuck_fb->pos = 0;
+ obuck_remains = obuck_hdr.length;
+ obuck_check_pad = (OBUCK_ALIGN - sizeof(obuck_hdr) - obuck_hdr.length - 4) & (OBUCK_ALIGN - 1);
+ return obuck_fb;
}
void
obuck_fetch_end(struct fastbuf *b UNUSED)
{
- if (bgetl(b) != OBUCK_TRAILER)
- obuck_broken("Corrupted trailer");
- obuck_unlock();
+}
+
+oid_t
+obuck_predict_last_oid(void)
+{
+ sh_off_t size = sh_seek(obuck_fd, 0, SEEK_END);
+ return size >> OBUCK_SHIFT;
}
struct fastbuf *
-obuck_write(void)
+obuck_create(u32 type)
{
obuck_lock_write();
- bseek(obuck_fb, 0, SEEK_END);
- start_of_this = btell(obuck_fb);
- if (start_of_this & (OBUCK_ALIGN - 1))
+ bflush(obuck_fb);
+ bucket_start = sh_seek(obuck_fd, 0, SEEK_END);
+ if (bucket_start & (OBUCK_ALIGN - 1))
obuck_broken("Misaligned file");
- obuck_hdr.magic = 0;
- obuck_hdr.oid = start_of_this >> OBUCK_SHIFT;
- obuck_hdr.length = obuck_hdr.orig_length = 0;
+ obuck_hdr.magic = OBUCK_INCOMPLETE_MAGIC;
+ obuck_hdr.oid = bucket_start >> OBUCK_SHIFT;
+ obuck_hdr.length = 0;
+ obuck_hdr.type = type;
+ bucket_current = bucket_start;
bwrite(obuck_fb, &obuck_hdr, sizeof(obuck_hdr));
+ obuck_fb->pos = -sizeof(obuck_hdr);
return obuck_fb;
}
void
-obuck_write_end(struct fastbuf *b UNUSED, struct obuck_header *hdrp)
+obuck_create_end(struct fastbuf *b UNUSED, struct obuck_header *hdrp)
{
int pad;
obuck_hdr.magic = OBUCK_MAGIC;
- obuck_hdr.length = obuck_hdr.orig_length = btell(obuck_fb) - start_of_this - sizeof(obuck_hdr);
- bputl(obuck_fb, OBUCK_TRAILER);
+ obuck_hdr.length = btell(obuck_fb);
pad = (OBUCK_ALIGN - sizeof(obuck_hdr) - obuck_hdr.length - 4) & (OBUCK_ALIGN - 1);
while (pad--)
bputc(obuck_fb, 0);
+ bputl(obuck_fb, OBUCK_TRAILER);
bflush(obuck_fb);
- bsetpos(obuck_fb, start_of_this);
- /* FIXME: Can be replaced with single pwrite */
- bwrite(obuck_fb, &obuck_hdr, sizeof(obuck_hdr));
- bflush(obuck_fb);
+ ASSERT(!(bucket_current & (OBUCK_ALIGN - 1)));
+ sh_pwrite(obuck_fd, &obuck_hdr, sizeof(obuck_hdr), bucket_start);
obuck_unlock();
memcpy(hdrp, &obuck_hdr, sizeof(obuck_hdr));
}
obuck_delete(oid_t oid)
{
obuck_lock_write();
- obuck_fetch_header(oid);
+ obuck_get(oid);
obuck_hdr.oid = OBUCK_OID_DELETED;
- bflush(obuck_fb);
- bsetpos(obuck_fb, start_of_this);
- bwrite(obuck_fb, &obuck_hdr, sizeof(obuck_hdr));
- bflush(obuck_fb);
+ sh_pwrite(obuck_fd, &obuck_hdr, sizeof(obuck_hdr), bucket_start);
obuck_unlock();
}
-struct fastbuf *
-obuck_walk_init(void)
+/*** Fast reading of the whole pool ***/
+
+static struct fastbuf *obuck_rpf;
+
+static int
+obuck_slurp_refill(struct fastbuf *f)
{
- start_of_this = start_of_next = 0;
- obuck_lock_read();
- return obuck_fb;
+ uns l;
+
+ if (!obuck_remains)
+ return 0;
+ l = bdirect_read_prepare(obuck_rpf, &f->buffer);
+ if (!l)
+ obuck_broken("Incomplete object");
+ l = MIN(l, obuck_remains);
+ bdirect_read_commit(obuck_rpf, f->buffer + l);
+ obuck_remains -= l;
+ f->bptr = f->buffer;
+ f->bufend = f->bstop = f->buffer + l;
+ return 1;
}
struct fastbuf *
-obuck_walk_next(struct fastbuf *b, struct obuck_header *hdrp)
+obuck_slurp_pool(struct obuck_header *hdrp)
{
- int c;
+ static struct fastbuf limiter;
+ uns l;
-restart:
- start_of_this = start_of_next;
- bsetpos(b, start_of_this);
- c = bgetc(b);
- if (c < 0)
- return NULL;
- bungetc(b, c);
- bread(b, &obuck_hdr, sizeof(obuck_hdr));
- if (obuck_hdr.magic != OBUCK_MAGIC)
- obuck_broken("Missing magic number");
- start_of_next = (start_of_this + sizeof(obuck_hdr) + obuck_hdr.orig_length +
- 4 + OBUCK_ALIGN - 1) & ~((sh_off_t)(OBUCK_ALIGN - 1));
- if (obuck_hdr.oid == OBUCK_OID_DELETED)
- goto restart;
- memcpy(hdrp, &obuck_hdr, sizeof(obuck_hdr));
- return b;
+ do
+ {
+ if (!obuck_rpf)
+ {
+ obuck_lock_read();
+ obuck_rpf = bopen(obuck_name, O_RDONLY, obuck_slurp_buflen);
+ }
+ else
+ {
+ bsetpos(obuck_rpf, bucket_current - 4);
+ if (bgetl(obuck_rpf) != OBUCK_TRAILER)
+ obuck_broken("Missing trailer");
+ }
+ bucket_start = btell(obuck_rpf);
+ l = bread(obuck_rpf, hdrp, sizeof(struct obuck_header));
+ if (!l)
+ {
+ bclose(obuck_rpf);
+ obuck_rpf = NULL;
+ obuck_unlock();
+ return NULL;
+ }
+ if (l != sizeof(struct obuck_header))
+ obuck_broken("Short header read");
+ if (hdrp->magic != OBUCK_MAGIC)
+ obuck_broken("Missing magic number");
+ bucket_current = (bucket_start + sizeof(obuck_hdr) + hdrp->length +
+ 4 + OBUCK_ALIGN - 1) & ~((sh_off_t)(OBUCK_ALIGN - 1));
+ }
+ while (hdrp->oid == OBUCK_OID_DELETED);
+ if (obuck_get_pos(hdrp->oid) != bucket_start)
+ obuck_broken("Invalid backlink");
+ obuck_remains = hdrp->length;
+ limiter.bptr = limiter.bstop = limiter.buffer = limiter.bufend = NULL;
+ limiter.name = "Bucket";
+ limiter.pos = 0;
+ limiter.refill = obuck_slurp_refill;
+ return &limiter;
}
+/*** Shakedown ***/
+
void
-obuck_walk_end(struct fastbuf *b UNUSED)
+obuck_shakedown(int (*kibitz)(struct obuck_header *old, oid_t new, byte *buck))
{
+ byte *rbuf, *wbuf, *msg;
+ sh_off_t rstart, wstart, w_bucket_start;
+ int roff, woff, rsize, l;
+ struct obuck_header *rhdr, *whdr;
+
+ rbuf = xmalloc(obuck_shake_buflen);
+ wbuf = xmalloc(obuck_shake_buflen);
+ rstart = wstart = 0;
+ roff = woff = rsize = 0;
+
+ /* We need to be the only accessor, all the object ID's are becoming invalid */
+ obuck_lock_write();
+
+ for(;;)
+ {
+ bucket_start = rstart + roff;
+ w_bucket_start = wstart + woff;
+ if (rsize - roff < OBUCK_ALIGN)
+ goto reread;
+ rhdr = (struct obuck_header *)(rbuf + roff);
+ if (rhdr->magic != OBUCK_MAGIC ||
+ rhdr->oid != OBUCK_OID_DELETED && rhdr->oid != (oid_t)(bucket_start >> OBUCK_SHIFT))
+ {
+ msg = "header mismatch";
+ goto broken;
+ }
+ l = (sizeof(struct obuck_header) + rhdr->length + 4 + OBUCK_ALIGN - 1) & ~(OBUCK_ALIGN-1);
+ if (l > obuck_shake_buflen)
+ {
+ if (rhdr->oid != OBUCK_OID_DELETED)
+ {
+ msg = "bucket longer than ShakeBufSize";
+ goto broken;
+ }
+ rstart = bucket_start + l;
+ roff = 0;
+ rsize = 0;
+ goto reread;
+ }
+ if (rsize - roff < l)
+ goto reread;
+ if (GET_U32(rbuf + roff + l - 4) != OBUCK_TRAILER)
+ {
+ msg = "missing trailer";
+ goto broken;
+ }
+ if (rhdr->oid != OBUCK_OID_DELETED)
+ {
+ if (kibitz(rhdr, w_bucket_start >> OBUCK_SHIFT, (byte *)(rhdr+1)))
+ {
+ if (bucket_start == w_bucket_start)
+ {
+ /* No copying needed now nor ever in the past, hence woff==0 */
+ wstart += l;
+ }
+ else
+ {
+ if (obuck_shake_buflen - woff < l)
+ {
+ if (sh_pwrite(obuck_fd, wbuf, woff, wstart) != woff)
+ die("obuck_shakedown write failed: %m");
+ wstart += woff;
+ woff = 0;
+ }
+ whdr = (struct obuck_header *)(wbuf+woff);
+ memcpy(whdr, rhdr, l);
+ whdr->oid = w_bucket_start >> OBUCK_SHIFT;
+ woff += l;
+ }
+ }
+ }
+ else
+ kibitz(rhdr, OBUCK_OID_DELETED, NULL);
+ roff += l;
+ continue;
+
+ reread:
+ if (roff)
+ {
+ memmove(rbuf, rbuf+roff, rsize-roff);
+ rsize -= roff;
+ rstart += roff;
+ roff = 0;
+ }
+ l = sh_pread(obuck_fd, rbuf+rsize, obuck_shake_buflen-rsize, rstart+rsize);
+ if (l < 0)
+ die("obuck_shakedown read error: %m");
+ if (!l)
+ {
+ if (!rsize)
+ break;
+ msg = "unexpected EOF";
+ goto broken;
+ }
+ rsize += l;
+ }
+ if (woff)
+ {
+ if (sh_pwrite(obuck_fd, wbuf, woff, wstart) != woff)
+ die("obuck_shakedown write failed: %m");
+ wstart += woff;
+ }
+ sh_ftruncate(obuck_fd, wstart);
+
obuck_unlock();
+ xfree(rbuf);
+ xfree(wbuf);
+ return;
+
+ broken:
+ log(L_ERROR, "Error during object pool shakedown: %s (pos=%Ld, id=%x), gathering debris", msg, (long long) bucket_start, (uns)(bucket_start >> OBUCK_SHIFT));
+ if (woff)
+ {
+ sh_pwrite(obuck_fd, wbuf, woff, wstart);
+ wstart += woff;
+ }
+ while (wstart + OBUCK_ALIGN <= bucket_start)
+ {
+ u32 check = OBUCK_TRAILER;
+ obuck_hdr.magic = OBUCK_MAGIC;
+ obuck_hdr.oid = OBUCK_OID_DELETED;
+ if (bucket_start - wstart < 0x40000000)
+ obuck_hdr.length = bucket_start - wstart - sizeof(obuck_hdr) - 4;
+ else
+ obuck_hdr.length = 0x40000000 - sizeof(obuck_hdr) - 4;
+ sh_pwrite(obuck_fd, &obuck_hdr, sizeof(obuck_hdr), wstart);
+ wstart += sizeof(obuck_hdr) + obuck_hdr.length + 4;
+ sh_pwrite(obuck_fd, &check, 4, wstart-4);
+ }
+ die("Fatal error during object pool shakedown");
}
+/*** Testing ***/
+
#ifdef TEST
-int main(void)
+
+#define COUNT 5000
+#define MAXLEN 10000
+#define KILLPERC 13
+#define LEN(i) ((259309*(i))%MAXLEN)
+
+int main(int argc, char **argv)
{
- int i, j;
+ int ids[COUNT];
+ unsigned int i, j, cnt;
struct obuck_header h;
struct fastbuf *b;
+
+ log_init(NULL);
+ if (cf_getopt(argc, argv, CF_SHORT_OPTS, CF_NO_LONG_OPTS, NULL) >= 0 ||
+ optind < argc)
+ {
+ fputs("This program supports only the following command-line arguments:\n" CF_USAGE, stderr);
+ exit(1);
+ }
+
+ unlink(obuck_name);
obuck_init(1);
- for(j=0; j<100; j++)
- {
- b = obuck_write();
- for(i=0; i<100*j; i++)
- bputc(b, i);
- obuck_write_end(b, &h);
- printf("%d\t%08x\t%d\n", j, h.oid, h.orig_length);
- }
- obuck_delete(0);
- b = obuck_walk_init();
- while (b = obuck_walk_next(b, &h))
+ for(j=0; j<COUNT; j++)
{
- printf("<<< %08x\t%d\n", h.oid, h.orig_length);
+ b = obuck_create();
+ for(i=0; i<LEN(j); i++)
+ bputc(b, (i+j) % 256);
+ obuck_create_end(b, &h);
+ printf("Writing %08x %d\n", h.oid, h.length);
+ ids[j] = h.oid;
}
- obuck_walk_end(b);
+ for(j=0; j<COUNT; j++)
+ if (j % 100 < KILLPERC)
+ {
+ printf("Deleting %08x\n", ids[j]);
+ obuck_delete(ids[j]);
+ }
+ cnt = 0;
+ for(j=0; j<COUNT; j++)
+ if (j % 100 >= KILLPERC)
+ {
+ cnt++;
+ h.oid = ids[j];
+ obuck_find_by_oid(&h);
+ b = obuck_fetch();
+ printf("Reading %08x %d\n", h.oid, h.length);
+ if (h.length != LEN(j))
+ die("Invalid length");
+ for(i=0; i<h.length; i++)
+ if ((unsigned) bgetc(b) != (i+j) % 256)
+ die("Contents mismatch");
+ if (bgetc(b) != EOF)
+ die("EOF mismatch");
+ obuck_fetch_end(b);
+ }
+ if (obuck_find_first(&h, 0))
+ do
+ {
+ printf("<<< %08x\t%d\n", h.oid, h.length);
+ cnt--;
+ }
+ while (obuck_find_next(&h, 0));
+ if (cnt)
+ die("Walk mismatch");
obuck_cleanup();
return 0;
}
+
#endif
projects / libucw.git / blobdiff