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iohelper: refactor copy operation as a separate function

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Signed-off-by: Claudio Fontana <cfontana@suse.de>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
This commit is contained in:
Claudio Fontana 2022-05-06 15:10:46 +02:00 committed by Daniel P. Berrangé
parent 8188716522
commit 42dc978c28
1 changed files with 75 additions and 56 deletions
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131
src/util/iohelper.c
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@ -55,17 +55,23 @@ struct runIOParams {
const char *fdoutname;
};
static int
runIO(const char *path, int fd, int oflags)
/**
* runIOCopy: execute the IO copy based on the passed parameters
* @p: the IO parameters
*
* Execute the copy based on the passed parameters.
*
* Returns: size transfered, or < 0 on error.
*/
static off_t
runIOCopy(const struct runIOParams p)
{
g_autofree void *base = NULL; /* Location to be freed */
char *buf = NULL; /* Aligned location within base */
size_t buflen = 1024*1024;
intptr_t alignMask = 64*1024 - 1;
int ret = -1;
off_t total = 0;
struct stat sb;
struct runIOParams p;
#if WITH_POSIX_MEMALIGN
if (posix_memalign(&base, alignMask + 1, buflen))
@ -77,6 +83,67 @@ runIO(const char *path, int fd, int oflags)
buf = (char *) (((intptr_t) base + alignMask) & ~alignMask);
#endif
while (1) {
ssize_t got;
/* If we read with O_DIRECT from file we can't use saferead as
* it can lead to unaligned read after reading last bytes.
* If we write with O_DIRECT use should use saferead so that
* writes will be aligned.
* In other cases using saferead reduces number of syscalls.
*/
if (!p.isWrite && p.isDirect) {
if ((got = read(p.fdin, buf, buflen)) < 0 &&
errno == EINTR)
continue;
} else {
got = saferead(p.fdin, buf, buflen);
}
if (got < 0) {
virReportSystemError(errno, _("Unable to read %s"), p.fdinname);
return -2;
}
if (got == 0)
break;
total += got;
/* handle last write size align in direct case */
if (got < buflen && p.isDirect && p.isWrite) {
ssize_t aligned_got = (got + alignMask) & ~alignMask;
memset(buf + got, 0, aligned_got - got);
if (safewrite(p.fdout, buf, aligned_got) < 0) {
virReportSystemError(errno, _("Unable to write %s"), p.fdoutname);
return -3;
}
if (!p.isBlockDev && ftruncate(p.fdout, total) < 0) {
virReportSystemError(errno, _("Unable to truncate %s"), p.fdoutname);
return -4;
}
break;
}
if (safewrite(p.fdout, buf, got) < 0) {
virReportSystemError(errno, _("Unable to write %s"), p.fdoutname);
return -3;
}
}
return total;
}
static int
runIO(const char *path, int fd, int oflags)
{
int ret = -1;
off_t total = 0;
struct stat sb;
struct runIOParams p;
if (fstat(fd, &sb) < 0) {
virReportSystemError(errno,
_("Unable to access file descriptor %d path %s"),
@ -125,57 +192,9 @@ runIO(const char *path, int fd, int oflags)
goto cleanup;
}
}
while (1) {
ssize_t got;
/* If we read with O_DIRECT from file we can't use saferead as
* it can lead to unaligned read after reading last bytes.
* If we write with O_DIRECT use should use saferead so that
* writes will be aligned.
* In other cases using saferead reduces number of syscalls.
*/
if (!p.isWrite && p.isDirect) {
if ((got = read(p.fdin, buf, buflen)) < 0 &&
errno == EINTR)
continue;
} else {
got = saferead(p.fdin, buf, buflen);
}
if (got < 0) {
virReportSystemError(errno, _("Unable to read %s"), p.fdinname);
goto cleanup;
}
if (got == 0)
break;
total += got;
/* handle last write size align in direct case */
if (got < buflen && p.isDirect && p.isWrite) {
ssize_t aligned_got = (got + alignMask) & ~alignMask;
memset(buf + got, 0, aligned_got - got);
if (safewrite(p.fdout, buf, aligned_got) < 0) {
virReportSystemError(errno, _("Unable to write %s"), p.fdoutname);
goto cleanup;
}
if (!p.isBlockDev && ftruncate(p.fdout, total) < 0) {
virReportSystemError(errno, _("Unable to truncate %s"), p.fdoutname);
goto cleanup;
}
break;
}
if (safewrite(p.fdout, buf, got) < 0) {
virReportSystemError(errno, _("Unable to write %s"), p.fdoutname);
goto cleanup;
}
}
total = runIOCopy(p);
if (total < 0)
goto cleanup;
/* Ensure all data is written */
if (virFileDataSync(p.fdout) < 0) {