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Generalize ef_extend() to non-file-backed tables

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ef_extend() extended the file bypassing the cache, which screws up the
cache if it's EFF_MEM.  It fixed that by closing and reopening the
table.  Cheesy, and worked only for file-backed tables.

Rewrite ef_extend() to remap the cache properly for EFF_MEM.  While
there, simplify the !EFF_MEM case: steal a cache slot instead of
allocating a buffer.

Factor cache mapping out of ef_open() and ef_extend() into new
ef_remap_cache().
This commit is contained in:
Markus Armbruster 2008-02-21 21:12:58 +01:00
parent 642c11eb64
commit d4ac7d94b2
1 changed files with 76 additions and 35 deletions
Download patch file Download diff file Expand all files Collapse all files

113
src/lib/common/file.c
View file

@ -46,8 +46,10 @@
#include "nsc.h"
#include "prototypes.h"
static int ef_remap_cache(struct empfile *, int);
static int fillcache(struct empfile *, int);
static int do_write(struct empfile *, void *, int, int);
static void ef_blank(struct empfile *, void *, int, int);
/*
* Open the file-backed table TYPE (EF_SECTOR, ...).
@ -61,7 +63,7 @@ ef_open(int type, int how)
{
struct empfile *ep;
struct flock lock;
int oflags, fd, fsiz, size;
int oflags, fd, fsiz, nslots;
if (ef_check(type) < 0)
return 0;
@ -116,18 +118,13 @@ ef_open(int type, int how)
}
}
} else {
if (how & EFF_MEM)
ep->csize = ep->fids;
else
ep->csize = blksize(fd) / ep->size;
/* 0 could lead to null cache, which confuses assertions */
if (!ep->csize)
ep->csize++;
size = ep->csize * ep->size;
if (CANT_HAPPEN(ep->cache))
free(ep->cache);
ep->cache = malloc(size);
if (ep->cache == NULL) {
if (how & EFF_MEM)
nslots = ep->fids;
else
nslots = blksize(fd) / ep->size;
if (!ef_remap_cache(ep, nslots)) {
logerror("Can't open %s: out of memory", ep->file);
close(fd);
return 0;
@ -151,6 +148,31 @@ ef_open(int type, int how)
return 1;
}
static int
ef_remap_cache(struct empfile *ep, int nslots)
{
void *cache;
if (CANT_HAPPEN(ep->flags & EFF_STATIC))
return 0;
if (CANT_HAPPEN(nslots < 0))
nslots = 0;
/*
* Avoid zero slots, because that can lead to null cache, which
* would be interpreted as unmapped cache.
*/
if (nslots == 0)
nslots++;
cache = realloc(ep->cache, nslots * ep->size);
if (!cache)
return 0;
ep->cache = cache;
ep->csize = nslots;
return 1;
}
/*
* Close the file-backed table TYPE (EF_SECTOR, ...).
* Return non-zero on success, zero on failure.
@ -384,47 +406,66 @@ ef_write(int type, int id, void *from)
}
/*
* Extend the file-backed table TYPE by COUNT elements.
* Can't extend privately mapped tables.
* Extend table TYPE by COUNT elements.
* Any pointers obtained from ef_ptr() become invalid.
* Return non-zero on success, zero on failure.
*/
int
ef_extend(int type, int count)
{
struct empfile *ep;
void *tmpobj;
int id, i, how;
char *p;
int i, id;
if (ef_check(type) < 0)
return 0;
ep = &empfile[type];
if (CANT_HAPPEN(ep->fd < 0 || count < 0))
if (CANT_HAPPEN(count < 0))
return 0;
if (CANT_HAPPEN(ep->flags & EFF_PRIVATE))
return 0; /* not implemented */
tmpobj = calloc(1, ep->size);
id = ep->fids;
for (i = 0; i < count; i++) {
if (ep->init)
ep->init(id + i, tmpobj);
if (do_write(ep, tmpobj, id + i, 1) < 0)
break;
}
free(tmpobj);
if (ep->flags & EFF_MEM) {
/* FIXME lazy bastards... do this right */
/* XXX this will cause problems if there are ef_ptrs (to the
* old allocated structure) active when we do the re-open */
how = ep->flags & ~EFF_IMMUTABLE;
ef_close(type);
ef_open(type, how);
} else {
ep->fids += i;
if (id + count > ep->csize) {
if (ep->flags & EFF_STATIC)
return 0;
if (!ef_remap_cache(ep, id + count))
return 0;
}
p = ep->cache + id * ep->size;
ef_blank(ep, p, id, count);
if (!(ep->flags & EFF_PRIVATE)) {
if (do_write(ep, p, id, count) < 0)
return 0;
}
ep->cids += count;
} else {
/* need a buffer, steal last cache slot */
if (ep->cids == ep->csize)
ep->cids--;
p = ep->cache + ep->cids * ep->size;
for (i = 0; i < count; i++) {
ef_blank(ep, p, id + i, 1);
if (do_write(ep, p, id + i, 1) < 0)
return 0;
}
}
ep->fids += count;
return 1;
}
return i == count;
/*
* Initialize COUNT elements of EP in BUF, starting with element ID.
*/
static void
ef_blank(struct empfile *ep, void *buf, int id, int count)
{
int i;
memset(buf, 0, count * ep->size);
if (ep->init) {
for (i = 0; i < count; i++)
ep->init(id + i, (char *)buf + i * ep->size);
}
}
struct castr *