* of the GNU Lesser General Public License.
*/
-/*
- * This fastbuf backend is intended for cases where several threads
- * of a single program append records to a single file and while the
- * record can mix in an arbitrary way, the bytes inside a single
- * record must remain uninterrupted.
- *
- * In case of files with fixed record size, we just allocate the
- * buffer to hold a whole number of records and take advantage
- * of the atomicity of the write() system call.
- *
- * With variable-sized records, we need another solution: when
- * writing a record, we keep the fastbuf in a locked state, which
- * prevents buffer flushing (and if the buffer becomes full, we extend it),
- * and we wait for an explicit commit operation which write()s the buffer
- * if the free space in the buffer falls below the expected maximum record
- * length.
- *
- * fbatomic_open() is called with the following parameters:
- * name - name of the file to open
- * master - fbatomic for the master thread or NULL if it's the first open
- * bufsize - initial buffer size
- * record_len - record length for fixed-size records;
- * or -(expected maximum record length) for variable-sized ones.
- */
-
#include "ucw/lib.h"
#include "ucw/fastbuf.h"
#include "ucw/lfs.h"
#include "ucw/conf.h"
+#include "ucw/trans.h"
#include <string.h>
#include <fcntl.h>
static uns trace;
+#ifndef TEST
+
static struct cf_section fbatomic_config = {
CF_ITEMS {
CF_UNS("Trace", &trace)
cf_declare_section("FBAtomic", &fbatomic_config, 1);
}
+#endif
+
#define TRACE(m...) do { if(trace) msg(L_DEBUG, "FB_ATOMIC: " m); } while(0)
struct fb_atomic_file {
ASSERT(af->record_len < 0 || !(size % af->record_len));
int res = write(af->fd, f->buffer, size);
if (res < 0)
- die("Error writing %s: %m", f->name);
+ bthrow(f, "write", "Error writing %s: %m", f->name);
if (res != size)
- die("Unexpected partial write to %s: written only %d bytes of %d", f->name, res, size);
+ bthrow(f, "write", "Unexpected partial write to %s: written only %d bytes of %d", f->name, res, size);
f->bptr = f->buffer;
}
}
fbatomic_close(struct fastbuf *f)
{
struct fb_atomic_file *af = FB_ATOMIC(f)->af;
- fbatomic_internal_write(f); /* Need to flush explicitly, because the file can be locked */
+ if (!(f->flags & FB_DEAD))
+ fbatomic_internal_write(f); /* Need to flush explicitly, because the file can be locked */
if (!--af->use_count)
{
close(af->fd);
}
else
{
+ int fd = ucw_open(name, O_WRONLY | O_CREAT | O_TRUNC | O_APPEND, 0666);
+ if (fd < 0)
+ trans_throw("ucw.fb.open", NULL, "Cannot create %s: %m", name);
af = xmalloc_zero(sizeof(*af) + strlen(name));
- if ((af->fd = ucw_open(name, O_WRONLY | O_CREAT | O_TRUNC | O_APPEND, 0666)) < 0)
- die("Cannot create %s: %m", name);
+ af->fd = fd;
af->use_count = 1;
af->record_len = record_len;
af->locked = (record_len < 0);