2:51 p.m.
changes v1 -> v2:
* fix missing write
changes v2 -> v3:
* move error reporting back into the copy function
* split into two patches, one introducing the IO parameters struct,
and another introducing the new function.
Claudio Fontana (2):
iohelper: introduce new struct to carry copy operation parameters
iohelper: refactor copy operation as a separate function
src/util/iohelper.c | 170 ++++++++++++++++++++++++++------------------
1 file changed, 100 insertions(+), 70 deletions(-)
--
2.34.1
2:51 p.m.
New subject: [libvirt PATCH v3 1/2] iohelper: introduce new struct to carry copy operation parameters
this is in preparation for a minor refactoring of the copy
function itself out of runIO().
Signed-off-by: Claudio Fontana <cfontana(a)suse.de>
---
src/util/iohelper.c | 95 +++++++++++++++++++++++++--------------------
1 file changed, 53 insertions(+), 42 deletions(-)
diff --git a/src/util/iohelper.c b/src/util/iohelper.c
index 2c91bf4f93..c13746a547 100644
--- a/src/util/iohelper.c
+++ b/src/util/iohelper.c
@@ -45,6 +45,16 @@
# define O_DIRECT 0
#endif
+struct runIOParams {
+ bool isBlockDev;
+ bool isDirect;
+ bool isWrite;
+ int fdin;
+ const char *fdinname;
+ int fdout;
+ const char *fdoutname;
+};
+
static int
runIO(const char *path, int fd, int oflags)
{
@@ -53,13 +63,9 @@ runIO(const char *path, int fd, int oflags)
size_t buflen = 1024*1024;
intptr_t alignMask = 64*1024 - 1;
int ret = -1;
- int fdin, fdout;
- const char *fdinname, *fdoutname;
- unsigned long long total = 0;
- bool direct = O_DIRECT && ((oflags & O_DIRECT) != 0);
- off_t end = 0;
+ off_t total = 0;
struct stat sb;
- bool isBlockDev = false;
+ struct runIOParams p;
#if WITH_POSIX_MEMALIGN
if (posix_memalign(&base, alignMask + 1, buflen))
@@ -77,34 +83,23 @@ runIO(const char *path, int fd, int oflags)
fd, path);
goto cleanup;
}
- isBlockDev = S_ISBLK(sb.st_mode);
+ p.isBlockDev = S_ISBLK(sb.st_mode);
+ p.isDirect = O_DIRECT && (oflags & O_DIRECT);
switch (oflags & O_ACCMODE) {
case O_RDONLY:
- fdin = fd;
- fdinname = path;
- fdout = STDOUT_FILENO;
- fdoutname = "stdout";
- /* To make the implementation simpler, we give up on any
- * attempt to use O_DIRECT in a non-trivial manner. */
- if (!isBlockDev && direct && ((end = lseek(fd, 0, SEEK_CUR)) !=
0)) {
- virReportSystemError(end < 0 ? errno : EINVAL, "%s",
- _("O_DIRECT read needs entire seekable
file"));
- goto cleanup;
- }
+ p.isWrite = false;
+ p.fdin = fd;
+ p.fdinname = path;
+ p.fdout = STDOUT_FILENO;
+ p.fdoutname = "stdout";
break;
case O_WRONLY:
- fdin = STDIN_FILENO;
- fdinname = "stdin";
- fdout = fd;
- fdoutname = path;
- /* To make the implementation simpler, we give up on any
- * attempt to use O_DIRECT in a non-trivial manner. */
- if (!isBlockDev && direct && (end = lseek(fd, 0, SEEK_END)) != 0)
{
- virReportSystemError(end < 0 ? errno : EINVAL, "%s",
- _("O_DIRECT write needs empty seekable
file"));
- goto cleanup;
- }
+ p.isWrite = true;
+ p.fdin = STDIN_FILENO;
+ p.fdinname = "stdin";
+ p.fdout = fd;
+ p.fdoutname = path;
break;
case O_RDWR:
@@ -114,6 +109,22 @@ runIO(const char *path, int fd, int oflags)
(oflags & O_ACCMODE));
goto cleanup;
}
+ /* To make the implementation simpler, we give up on any
+ * attempt to use O_DIRECT in a non-trivial manner. */
+ if (!p.isBlockDev && p.isDirect) {
+ off_t off;
+ if (p.isWrite) {
+ if ((off = lseek(fd, 0, SEEK_END)) != 0) {
+ virReportSystemError(off < 0 ? errno : EINVAL, "%s",
+ _("O_DIRECT write needs empty seekable
file"));
+ goto cleanup;
+ }
+ } else if ((off = lseek(fd, 0, SEEK_CUR)) != 0) {
+ virReportSystemError(off < 0 ? errno : EINVAL, "%s",
+ _("O_DIRECT read needs entire seekable
file"));
+ goto cleanup;
+ }
+ }
while (1) {
ssize_t got;
@@ -124,16 +135,16 @@ runIO(const char *path, int fd, int oflags)
* writes will be aligned.
* In other cases using saferead reduces number of syscalls.
*/
- if (fdin == fd && direct) {
- if ((got = read(fdin, buf, buflen)) < 0 &&
+ if (!p.isWrite && p.isDirect) {
+ if ((got = read(p.fdin, buf, buflen)) < 0 &&
errno == EINTR)
continue;
} else {
- got = saferead(fdin, buf, buflen);
+ got = saferead(p.fdin, buf, buflen);
}
if (got < 0) {
- virReportSystemError(errno, _("Unable to read %s"), fdinname);
+ virReportSystemError(errno, _("Unable to read %s"), p.fdinname);
goto cleanup;
}
if (got == 0)
@@ -142,35 +153,35 @@ runIO(const char *path, int fd, int oflags)
total += got;
/* handle last write size align in direct case */
- if (got < buflen && direct && fdout == fd) {
+ if (got < buflen && p.isDirect && p.isWrite) {
ssize_t aligned_got = (got + alignMask) & ~alignMask;
memset(buf + got, 0, aligned_got - got);
- if (safewrite(fdout, buf, aligned_got) < 0) {
- virReportSystemError(errno, _("Unable to write %s"),
fdoutname);
+ if (safewrite(p.fdout, buf, aligned_got) < 0) {
+ virReportSystemError(errno, _("Unable to write %s"),
p.fdoutname);
goto cleanup;
}
- if (!isBlockDev && ftruncate(fd, total) < 0) {
- virReportSystemError(errno, _("Unable to truncate %s"),
fdoutname);
+ if (!p.isBlockDev && ftruncate(p.fdout, total) < 0) {
+ virReportSystemError(errno, _("Unable to truncate %s"),
p.fdoutname);
goto cleanup;
}
break;
}
- if (safewrite(fdout, buf, got) < 0) {
- virReportSystemError(errno, _("Unable to write %s"), fdoutname);
+ if (safewrite(p.fdout, buf, got) < 0) {
+ virReportSystemError(errno, _("Unable to write %s"), p.fdoutname);
goto cleanup;
}
}
/* Ensure all data is written */
- if (virFileDataSync(fdout) < 0) {
+ if (virFileDataSync(p.fdout) < 0) {
if (errno != EINVAL && errno != EROFS) {
/* fdatasync() may fail on some special FDs, e.g. pipes */
- virReportSystemError(errno, _("unable to fsync %s"), fdoutname);
+ virReportSystemError(errno, _("unable to fsync %s"), p.fdoutname);
goto cleanup;
}
}
--
2.34.1
2:51 p.m.
New subject: [libvirt PATCH v3 2/2] iohelper: refactor copy operation as a separate function
Signed-off-by: Claudio Fontana <cfontana(a)suse.de>
---
src/util/iohelper.c | 131 +++++++++++++++++++++++++-------------------
1 file changed, 75 insertions(+), 56 deletions(-)
diff --git a/src/util/iohelper.c b/src/util/iohelper.c
index c13746a547..1584321839 100644
--- a/src/util/iohelper.c
+++ b/src/util/iohelper.c
@@ -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) {
--
2.34.1
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Claudio Fontana