* [PATCH 0/3] block: improve error reporting for unsupported O_DIRECT
@ 2020-07-01 16:05 Daniel P. Berrangé
2020-07-01 16:05 ` [PATCH 1/3] util: validate whether O_DIRECT is supported after failure Daniel P. Berrangé
` (3 more replies)
0 siblings, 4 replies; 8+ messages in thread
From: Daniel P. Berrangé @ 2020-07-01 16:05 UTC (permalink / raw)
To: qemu-devel
Cc: Kevin Wolf, P J P, Daniel P. Berrangé, qemu-block, Max Reitz
To repeat the commit message from patch 3...
Currently at startup if using cache=none on a filesystem lacking
O_DIRECT such as tmpfs, at startup QEMU prints
qemu-system-x86_64: -drive file=/tmp/foo.img,cache=none: file system may not support O_DIRECT
qemu-system-x86_64: -drive file=/tmp/foo.img,cache=none: Could not open '/tmp/foo.img': Invalid argument
while at QMP level the hint is missing, so QEMU reports just
"error": {
"class": "GenericError",
"desc": "Could not open '/tmp/foo.img': Invalid argument"
}
which is close to useless for the end user trying to figure out what
they did wrong
With this change at startup QEMU prints
qemu-system-x86_64: -drive file=/tmp/foo.img,cache=none: Unable to open '/tmp/foo.img' flags 0x4000: filesystem does not support O_DIRECT
while at the QMP level QEMU reports a massively more informative
"error": {
"class": "GenericError",
"desc": "Unable to open '/tmp/foo.img' flags 0x4002: filesystem does not support O_DIRECT"
}
qemu_open is used in many more places besides block layer, but
converting those to qemu_open_err is left as an exercise for
other maintainers.
Daniel P. Berrangé (3):
util: validate whether O_DIRECT is supported after failure
util: support detailed error reporting for qemu_open
block: switch to use qemu_open_err for improved errors
block/file-posix.c | 10 +++----
include/qemu/osdep.h | 1 +
util/osdep.c | 70 ++++++++++++++++++++++++++++++++++++++------
3 files changed, 66 insertions(+), 15 deletions(-)
--
2.26.2
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 1/3] util: validate whether O_DIRECT is supported after failure
2020-07-01 16:05 [PATCH 0/3] block: improve error reporting for unsupported O_DIRECT Daniel P. Berrangé
@ 2020-07-01 16:05 ` Daniel P. Berrangé
2020-07-02 10:10 ` Philippe Mathieu-Daudé
2020-07-01 16:05 ` [PATCH 2/3] util: support detailed error reporting for qemu_open Daniel P. Berrangé
` (2 subsequent siblings)
3 siblings, 1 reply; 8+ messages in thread
From: Daniel P. Berrangé @ 2020-07-01 16:05 UTC (permalink / raw)
To: qemu-devel
Cc: Kevin Wolf, P J P, Daniel P. Berrangé, qemu-block, Max Reitz
Currently we suggest that a filesystem may not support O_DIRECT after
seeing an EINVAL. Other things can cause EINVAL though, so it is better
to do an explicit check, and then report a definitive error message.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
util/osdep.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/util/osdep.c b/util/osdep.c
index 4829c07ff6..4bdbe81cec 100644
--- a/util/osdep.c
+++ b/util/osdep.c
@@ -342,8 +342,17 @@ int qemu_open(const char *name, int flags, ...)
#ifdef O_DIRECT
if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) {
- error_report("file system may not support O_DIRECT");
- errno = EINVAL; /* in case it was clobbered */
+ int newflags = flags & ~O_DIRECT;
+# ifdef O_CLOEXEC
+ ret = open(name, newflags | O_CLOEXEC, mode);
+# else
+ ret = open(name, newflags, mode);
+# endif
+ if (ret != -1) {
+ close(ret);
+ error_report("file system does not support O_DIRECT");
+ errno = EINVAL;
+ }
}
#endif /* O_DIRECT */
--
2.26.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 2/3] util: support detailed error reporting for qemu_open
2020-07-01 16:05 [PATCH 0/3] block: improve error reporting for unsupported O_DIRECT Daniel P. Berrangé
2020-07-01 16:05 ` [PATCH 1/3] util: validate whether O_DIRECT is supported after failure Daniel P. Berrangé
@ 2020-07-01 16:05 ` Daniel P. Berrangé
2020-07-02 5:13 ` Markus Armbruster
2020-07-01 16:05 ` [PATCH 3/3] block: switch to use qemu_open_err for improved errors Daniel P. Berrangé
2020-07-01 16:58 ` [PATCH 0/3] block: improve error reporting for unsupported O_DIRECT no-reply
3 siblings, 1 reply; 8+ messages in thread
From: Daniel P. Berrangé @ 2020-07-01 16:05 UTC (permalink / raw)
To: qemu-devel
Cc: Kevin Wolf, P J P, Daniel P. Berrangé, qemu-block, Max Reitz
Create a "qemu_open_err" method which does the same as "qemu_open",
but with a "Error **errp" for error reporting. There should be no
behavioural difference for existing callers at this stage.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
include/qemu/osdep.h | 1 +
util/osdep.c | 71 +++++++++++++++++++++++++++++++++++---------
2 files changed, 58 insertions(+), 14 deletions(-)
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 0d26a1b9bd..e41701a308 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -483,6 +483,7 @@ int qemu_madvise(void *addr, size_t len, int advice);
int qemu_mprotect_rwx(void *addr, size_t size);
int qemu_mprotect_none(void *addr, size_t size);
+int qemu_open_err(const char *name, int flags, Error **errp, ...);
int qemu_open(const char *name, int flags, ...);
int qemu_close(int fd);
int qemu_unlink(const char *name);
diff --git a/util/osdep.c b/util/osdep.c
index 4bdbe81cec..450b3a5da3 100644
--- a/util/osdep.c
+++ b/util/osdep.c
@@ -22,6 +22,7 @@
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
+#include "qapi/error.h"
/* Needed early for CONFIG_BSD etc. */
@@ -282,7 +283,7 @@ int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive)
/*
* Opens a file with FD_CLOEXEC set
*/
-int qemu_open(const char *name, int flags, ...)
+static int qemu_openv(const char *name, int flags, Error **errp, va_list ap)
{
int ret;
int mode = 0;
@@ -297,24 +298,31 @@ int qemu_open(const char *name, int flags, ...)
fdset_id = qemu_parse_fdset(fdset_id_str);
if (fdset_id == -1) {
+ error_setg(errp, "Unable to parse fdset %s", name);
errno = EINVAL;
return -1;
}
fd = monitor_fdset_get_fd(fdset_id, flags);
if (fd < 0) {
+ error_setg_errno(errp, -fd, "Unable acquire FD for %s flags %x",
+ name, flags);
errno = -fd;
return -1;
}
dupfd = qemu_dup_flags(fd, flags);
if (dupfd == -1) {
+ error_setg_errno(errp, errno, "Unable dup FD for %s flags %x",
+ name, flags);
return -1;
}
ret = monitor_fdset_dup_fd_add(fdset_id, dupfd);
if (ret == -1) {
close(dupfd);
+ error_setg(errp, "Unable save FD for %s flags %x",
+ name, flags);
errno = EINVAL;
return -1;
}
@@ -324,11 +332,7 @@ int qemu_open(const char *name, int flags, ...)
#endif
if (flags & O_CREAT) {
- va_list ap;
-
- va_start(ap, flags);
mode = va_arg(ap, int);
- va_end(ap);
}
#ifdef O_CLOEXEC
@@ -340,25 +344,64 @@ int qemu_open(const char *name, int flags, ...)
}
#endif
+ if (ret == -1) {
+ const char *action = "open";
+ if (flags & O_CREAT) {
+ action = "create";
+ }
#ifdef O_DIRECT
- if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) {
- int newflags = flags & ~O_DIRECT;
+ if (errno == EINVAL && (flags & O_DIRECT)) {
+ int newflags = flags & ~O_DIRECT;
# ifdef O_CLOEXEC
- ret = open(name, newflags | O_CLOEXEC, mode);
+ ret = open(name, newflags | O_CLOEXEC, mode);
# else
- ret = open(name, newflags, mode);
+ ret = open(name, newflags, mode);
# endif
- if (ret != -1) {
- close(ret);
- error_report("file system does not support O_DIRECT");
- errno = EINVAL;
+ if (ret != -1) {
+ close(ret);
+ error_setg(errp, "Unable to %s '%s' flags 0x%x: "
+ "filesystem does not support O_DIRECT",
+ action, name, flags);
+ if (!errp) {
+ error_report("file system does not support O_DIRECT");
+ }
+ errno = EINVAL;
+ return -1;
+ }
}
- }
#endif /* O_DIRECT */
+ error_setg_errno(errp, errno, "Unable to %s '%s' flags 0x%x",
+ action, name, flags);
+ }
+
return ret;
}
+int qemu_open_err(const char *name, int flags, Error **errp, ...)
+{
+ va_list ap;
+ int rv;
+
+ va_start(ap, errp);
+ rv = qemu_openv(name, flags, errp, ap);
+ va_end(ap);
+
+ return rv;
+}
+
+int qemu_open(const char *name, int flags, ...)
+{
+ va_list ap;
+ int rv;
+
+ va_start(ap, flags);
+ rv = qemu_openv(name, flags, NULL, ap);
+ va_end(ap);
+
+ return rv;
+}
+
int qemu_close(int fd)
{
int64_t fdset_id;
--
2.26.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH 3/3] block: switch to use qemu_open_err for improved errors
2020-07-01 16:05 [PATCH 0/3] block: improve error reporting for unsupported O_DIRECT Daniel P. Berrangé
2020-07-01 16:05 ` [PATCH 1/3] util: validate whether O_DIRECT is supported after failure Daniel P. Berrangé
2020-07-01 16:05 ` [PATCH 2/3] util: support detailed error reporting for qemu_open Daniel P. Berrangé
@ 2020-07-01 16:05 ` Daniel P. Berrangé
2020-07-01 16:58 ` [PATCH 0/3] block: improve error reporting for unsupported O_DIRECT no-reply
3 siblings, 0 replies; 8+ messages in thread
From: Daniel P. Berrangé @ 2020-07-01 16:05 UTC (permalink / raw)
To: qemu-devel
Cc: Kevin Wolf, P J P, Daniel P. Berrangé, qemu-block, Max Reitz
Currently at startup if using cache=none on a filesystem lacking
O_DIRECT such as tmpfs, at startup QEMU prints
qemu-system-x86_64: -drive file=/tmp/foo.img,cache=none: file system may not support O_DIRECT
qemu-system-x86_64: -drive file=/tmp/foo.img,cache=none: Could not open '/tmp/foo.img': Invalid argument
while at QMP level the hint is missing, so QEMU reports just
"error": {
"class": "GenericError",
"desc": "Could not open '/tmp/foo.img': Invalid argument"
}
which is close to useless for the end user trying to figure out what
they did wrong
With this change at startup QEMU prints
qemu-system-x86_64: -drive file=/tmp/foo.img,cache=none: Unable to open '/tmp/foo.img' flags 0x4000: filesystem does not support O_DIRECT
while at the QMP level QEMU reports a massively more informative
"error": {
"class": "GenericError",
"desc": "Unable to open '/tmp/foo.img' flags 0x4002: filesystem does not support O_DIRECT"
}
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
block/file-posix.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/block/file-posix.c b/block/file-posix.c
index 3ab8f5a0fa..2865b789fb 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -574,11 +574,10 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
raw_parse_flags(bdrv_flags, &s->open_flags, false);
s->fd = -1;
- fd = qemu_open(filename, s->open_flags, 0644);
+ fd = qemu_open_err(filename, s->open_flags, errp, 0644);
ret = fd < 0 ? -errno : 0;
if (ret < 0) {
- error_setg_file_open(errp, -ret, filename);
if (ret == -EROFS) {
ret = -EACCES;
}
@@ -970,9 +969,8 @@ static int raw_reconfigure_getfd(BlockDriverState *bs, int flags,
ret = raw_normalize_devicepath(&normalized_filename, errp);
if (ret >= 0) {
assert(!(*open_flags & O_CREAT));
- fd = qemu_open(normalized_filename, *open_flags);
+ fd = qemu_open_err(normalized_filename, *open_flags, errp);
if (fd == -1) {
- error_setg_errno(errp, errno, "Could not reopen file");
return -1;
}
}
@@ -2324,10 +2322,10 @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)
}
/* Create file */
- fd = qemu_open(file_opts->filename, O_RDWR | O_CREAT | O_BINARY, 0644);
+ fd = qemu_open_err(file_opts->filename, O_RDWR | O_CREAT | O_BINARY,
+ errp, 0644);
if (fd < 0) {
result = -errno;
- error_setg_errno(errp, -result, "Could not create file");
goto out;
}
--
2.26.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 0/3] block: improve error reporting for unsupported O_DIRECT
2020-07-01 16:05 [PATCH 0/3] block: improve error reporting for unsupported O_DIRECT Daniel P. Berrangé
` (2 preceding siblings ...)
2020-07-01 16:05 ` [PATCH 3/3] block: switch to use qemu_open_err for improved errors Daniel P. Berrangé
@ 2020-07-01 16:58 ` no-reply
3 siblings, 0 replies; 8+ messages in thread
From: no-reply @ 2020-07-01 16:58 UTC (permalink / raw)
To: berrange; +Cc: kwolf, berrange, qemu-block, qemu-devel, mreitz, ppandit
Patchew URL: https://patchew.org/QEMU/20200701160509.1523847-1-berrange@redhat.com/
Hi,
This series failed the docker-quick@centos7 build test. Please find the testing commands and
their output below. If you have Docker installed, you can probably reproduce it
locally.
=== TEST SCRIPT BEGIN ===
#!/bin/bash
make docker-image-centos7 V=1 NETWORK=1
time make docker-test-quick@centos7 SHOW_ENV=1 J=14 NETWORK=1
=== TEST SCRIPT END ===
+++ /tmp/qemu-test/build/tests/qemu-iotests/226.out.bad 2020-07-01 16:58:11.321029717 +0000
@@ -6,7 +6,7 @@
qemu-io: can't open: A regular file was expected by the 'file' driver, but something else was given
qemu-io: warning: Opening a character device as a file using the 'file' driver is deprecated
== Testing RW ==
-qemu-io: can't open: Could not open 'TEST_DIR/t.IMGFMT': Is a directory
+qemu-io: can't open: Unable to open 'TEST_DIR/t.IMGFMT' flags 0x2: Is a directory
qemu-io: warning: Opening a character device as a file using the 'file' driver is deprecated
=== Testing with driver:host_device ===
@@ -14,13 +14,13 @@
---
Not run: 259
Failures: 061 069 111 226 244
Failed 5 of 119 iotests
make: *** [check-tests/check-block.sh] Error 1
Traceback (most recent call last):
File "./tests/docker/docker.py", line 669, in <module>
sys.exit(main())
---
raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['sudo', '-n', 'docker', 'run', '--label', 'com.qemu.instance.uuid=67228a70e7844d70b07a864fef5c4569', '-u', '1003', '--security-opt', 'seccomp=unconfined', '--rm', '-e', 'TARGET_LIST=', '-e', 'EXTRA_CONFIGURE_OPTS=', '-e', 'V=', '-e', 'J=14', '-e', 'DEBUG=', '-e', 'SHOW_ENV=1', '-e', 'CCACHE_DIR=/var/tmp/ccache', '-v', '/home/patchew2/.cache/qemu-docker-ccache:/var/tmp/ccache:z', '-v', '/var/tmp/patchew-tester-tmp-y2quzqfb/src/docker-src.2020-07-01-12.41.12.23538:/var/tmp/qemu:z,ro', 'qemu:centos7', '/var/tmp/qemu/run', 'test-quick']' returned non-zero exit status 2.
filter=--filter=label=com.qemu.instance.uuid=67228a70e7844d70b07a864fef5c4569
make[1]: *** [docker-run] Error 1
make[1]: Leaving directory `/var/tmp/patchew-tester-tmp-y2quzqfb/src'
make: *** [docker-run-test-quick@centos7] Error 2
real 17m41.892s
user 0m5.790s
The full log is available at
http://patchew.org/logs/20200701160509.1523847-1-berrange@redhat.com/testing.docker-quick@centos7/?type=message.
---
Email generated automatically by Patchew [https://patchew.org/].
Please send your feedback to patchew-devel@redhat.com
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 2/3] util: support detailed error reporting for qemu_open
2020-07-01 16:05 ` [PATCH 2/3] util: support detailed error reporting for qemu_open Daniel P. Berrangé
@ 2020-07-02 5:13 ` Markus Armbruster
2020-07-02 9:30 ` Daniel P. Berrangé
0 siblings, 1 reply; 8+ messages in thread
From: Markus Armbruster @ 2020-07-02 5:13 UTC (permalink / raw)
To: Daniel P. Berrangé
Cc: Kevin Wolf, qemu-block, qemu-devel, Max Reitz, Stefan Hajnoczi, P J P
Daniel P. Berrangé <berrange@redhat.com> writes:
> Create a "qemu_open_err" method which does the same as "qemu_open",
> but with a "Error **errp" for error reporting. There should be no
> behavioural difference for existing callers at this stage.
>
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
> include/qemu/osdep.h | 1 +
> util/osdep.c | 71 +++++++++++++++++++++++++++++++++++---------
> 2 files changed, 58 insertions(+), 14 deletions(-)
>
> diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> index 0d26a1b9bd..e41701a308 100644
> --- a/include/qemu/osdep.h
> +++ b/include/qemu/osdep.h
> @@ -483,6 +483,7 @@ int qemu_madvise(void *addr, size_t len, int advice);
> int qemu_mprotect_rwx(void *addr, size_t size);
> int qemu_mprotect_none(void *addr, size_t size);
>
> +int qemu_open_err(const char *name, int flags, Error **errp, ...);
> int qemu_open(const char *name, int flags, ...);
> int qemu_close(int fd);
> int qemu_unlink(const char *name);
> diff --git a/util/osdep.c b/util/osdep.c
> index 4bdbe81cec..450b3a5da3 100644
> --- a/util/osdep.c
> +++ b/util/osdep.c
> @@ -22,6 +22,7 @@
> * THE SOFTWARE.
> */
> #include "qemu/osdep.h"
> +#include "qapi/error.h"
>
> /* Needed early for CONFIG_BSD etc. */
>
> @@ -282,7 +283,7 @@ int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive)
> /*
> * Opens a file with FD_CLOEXEC set
> */
> -int qemu_open(const char *name, int flags, ...)
> +static int qemu_openv(const char *name, int flags, Error **errp, va_list ap)
> {
> int ret;
> int mode = 0;
> @@ -297,24 +298,31 @@ int qemu_open(const char *name, int flags, ...)
>
> fdset_id = qemu_parse_fdset(fdset_id_str);
> if (fdset_id == -1) {
> + error_setg(errp, "Unable to parse fdset %s", name);
> errno = EINVAL;
> return -1;
> }
>
> fd = monitor_fdset_get_fd(fdset_id, flags);
> if (fd < 0) {
> + error_setg_errno(errp, -fd, "Unable acquire FD for %s flags %x",
> + name, flags);
> errno = -fd;
> return -1;
> }
>
> dupfd = qemu_dup_flags(fd, flags);
> if (dupfd == -1) {
> + error_setg_errno(errp, errno, "Unable dup FD for %s flags %x",
> + name, flags);
> return -1;
> }
>
> ret = monitor_fdset_dup_fd_add(fdset_id, dupfd);
> if (ret == -1) {
> close(dupfd);
> + error_setg(errp, "Unable save FD for %s flags %x",
> + name, flags);
> errno = EINVAL;
> return -1;
> }
> @@ -324,11 +332,7 @@ int qemu_open(const char *name, int flags, ...)
> #endif
>
> if (flags & O_CREAT) {
> - va_list ap;
> -
> - va_start(ap, flags);
> mode = va_arg(ap, int);
> - va_end(ap);
> }
>
> #ifdef O_CLOEXEC
> @@ -340,25 +344,64 @@ int qemu_open(const char *name, int flags, ...)
> }
> #endif
>
> + if (ret == -1) {
> + const char *action = "open";
> + if (flags & O_CREAT) {
> + action = "create";
> + }
> #ifdef O_DIRECT
> - if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) {
> - int newflags = flags & ~O_DIRECT;
> + if (errno == EINVAL && (flags & O_DIRECT)) {
> + int newflags = flags & ~O_DIRECT;
> # ifdef O_CLOEXEC
> - ret = open(name, newflags | O_CLOEXEC, mode);
> + ret = open(name, newflags | O_CLOEXEC, mode);
> # else
> - ret = open(name, newflags, mode);
> + ret = open(name, newflags, mode);
> # endif
> - if (ret != -1) {
> - close(ret);
> - error_report("file system does not support O_DIRECT");
> - errno = EINVAL;
> + if (ret != -1) {
> + close(ret);
> + error_setg(errp, "Unable to %s '%s' flags 0x%x: "
> + "filesystem does not support O_DIRECT",
> + action, name, flags);
> + if (!errp) {
If the caller ignores errors, ...
> + error_report("file system does not support O_DIRECT");
... we report this error to stderr (but not any of the other ones).
This is weird. I figure you do it here to reproduce the weirdness of
qemu_open() before the patch. Goes back to
commit a5813077aac7865f69b7ee46a594f3705429f7cd
Author: Stefan Hajnoczi <stefanha@redhat.com>
Date: Thu Aug 22 11:29:03 2013 +0200
osdep: warn if open(O_DIRECT) on fails with EINVAL
Print a warning when opening a file O_DIRECT fails with EINVAL. This
saves users a lot of time trying to figure out the EINVAL error, which
is typical when attempting to open a file O_DIRECT on Linux tmpfs.
Reported-by: Deepak C Shetty <deepakcs@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
The message isn't phrased as a warning, though. Should it use
warn_report()? Stefan?
Regardless, since use of error_report() in a function that returns
errors through its Error ** parameter is an anti-pattern, this use needs
a comment. I'd make it a TODO comment: convert all callers where the
warning is wanted to qemu_open_err(), then drop it.
> + }
> + errno = EINVAL;
> + return -1;
> + }
> }
> - }
> #endif /* O_DIRECT */
> + error_setg_errno(errp, errno, "Unable to %s '%s' flags 0x%x",
> + action, name, flags);
> + }
> +
>
> return ret;
> }
>
> +int qemu_open_err(const char *name, int flags, Error **errp, ...)
> +{
> + va_list ap;
> + int rv;
> +
> + va_start(ap, errp);
> + rv = qemu_openv(name, flags, errp, ap);
> + va_end(ap);
> +
> + return rv;
> +}
> +
> +int qemu_open(const char *name, int flags, ...)
> +{
> + va_list ap;
> + int rv;
> +
> + va_start(ap, flags);
> + rv = qemu_openv(name, flags, NULL, ap);
> + va_end(ap);
> +
> + return rv;
> +}
I'd rename this to qemu_open_with_bad_error_messages().
For better ones, callers can use
if (qemu_open_err(name, flags, &err) < 0) {
error_report_err(err);
...
}
or, where the error is fatal
qemu_open_err(name, flags, &error_fatal);
If you prefer not to rename it now, please add a comment why it should
not be used in new code, and existing uses should be converted.
If you rename, call the new one qemu_open().
> +
> int qemu_close(int fd)
> {
> int64_t fdset_id;
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 2/3] util: support detailed error reporting for qemu_open
2020-07-02 5:13 ` Markus Armbruster
@ 2020-07-02 9:30 ` Daniel P. Berrangé
0 siblings, 0 replies; 8+ messages in thread
From: Daniel P. Berrangé @ 2020-07-02 9:30 UTC (permalink / raw)
To: Markus Armbruster
Cc: Kevin Wolf, qemu-block, qemu-devel, Max Reitz, Stefan Hajnoczi, P J P
On Thu, Jul 02, 2020 at 07:13:08AM +0200, Markus Armbruster wrote:
> Daniel P. Berrangé <berrange@redhat.com> writes:
>
> > Create a "qemu_open_err" method which does the same as "qemu_open",
> > but with a "Error **errp" for error reporting. There should be no
> > behavioural difference for existing callers at this stage.
> >
> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> > ---
> > include/qemu/osdep.h | 1 +
> > util/osdep.c | 71 +++++++++++++++++++++++++++++++++++---------
> > 2 files changed, 58 insertions(+), 14 deletions(-)
> >
> > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> > index 0d26a1b9bd..e41701a308 100644
> > --- a/include/qemu/osdep.h
> > +++ b/include/qemu/osdep.h
> > @@ -483,6 +483,7 @@ int qemu_madvise(void *addr, size_t len, int advice);
> > int qemu_mprotect_rwx(void *addr, size_t size);
> > int qemu_mprotect_none(void *addr, size_t size);
> >
> > +int qemu_open_err(const char *name, int flags, Error **errp, ...);
> > int qemu_open(const char *name, int flags, ...);
> > int qemu_close(int fd);
> > int qemu_unlink(const char *name);
> > diff --git a/util/osdep.c b/util/osdep.c
> > index 4bdbe81cec..450b3a5da3 100644
> > --- a/util/osdep.c
> > +++ b/util/osdep.c
> > @@ -22,6 +22,7 @@
> > * THE SOFTWARE.
> > */
> > #include "qemu/osdep.h"
> > +#include "qapi/error.h"
> >
> > /* Needed early for CONFIG_BSD etc. */
> >
> > @@ -282,7 +283,7 @@ int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive)
> > /*
> > * Opens a file with FD_CLOEXEC set
> > */
> > -int qemu_open(const char *name, int flags, ...)
> > +static int qemu_openv(const char *name, int flags, Error **errp, va_list ap)
> > {
> > int ret;
> > int mode = 0;
> > @@ -297,24 +298,31 @@ int qemu_open(const char *name, int flags, ...)
> >
> > fdset_id = qemu_parse_fdset(fdset_id_str);
> > if (fdset_id == -1) {
> > + error_setg(errp, "Unable to parse fdset %s", name);
> > errno = EINVAL;
> > return -1;
> > }
> >
> > fd = monitor_fdset_get_fd(fdset_id, flags);
> > if (fd < 0) {
> > + error_setg_errno(errp, -fd, "Unable acquire FD for %s flags %x",
> > + name, flags);
> > errno = -fd;
> > return -1;
> > }
> >
> > dupfd = qemu_dup_flags(fd, flags);
> > if (dupfd == -1) {
> > + error_setg_errno(errp, errno, "Unable dup FD for %s flags %x",
> > + name, flags);
> > return -1;
> > }
> >
> > ret = monitor_fdset_dup_fd_add(fdset_id, dupfd);
> > if (ret == -1) {
> > close(dupfd);
> > + error_setg(errp, "Unable save FD for %s flags %x",
> > + name, flags);
> > errno = EINVAL;
> > return -1;
> > }
> > @@ -324,11 +332,7 @@ int qemu_open(const char *name, int flags, ...)
> > #endif
> >
> > if (flags & O_CREAT) {
> > - va_list ap;
> > -
> > - va_start(ap, flags);
> > mode = va_arg(ap, int);
> > - va_end(ap);
> > }
> >
> > #ifdef O_CLOEXEC
> > @@ -340,25 +344,64 @@ int qemu_open(const char *name, int flags, ...)
> > }
> > #endif
> >
> > + if (ret == -1) {
> > + const char *action = "open";
> > + if (flags & O_CREAT) {
> > + action = "create";
> > + }
> > #ifdef O_DIRECT
> > - if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) {
> > - int newflags = flags & ~O_DIRECT;
> > + if (errno == EINVAL && (flags & O_DIRECT)) {
> > + int newflags = flags & ~O_DIRECT;
> > # ifdef O_CLOEXEC
> > - ret = open(name, newflags | O_CLOEXEC, mode);
> > + ret = open(name, newflags | O_CLOEXEC, mode);
> > # else
> > - ret = open(name, newflags, mode);
> > + ret = open(name, newflags, mode);
> > # endif
> > - if (ret != -1) {
> > - close(ret);
> > - error_report("file system does not support O_DIRECT");
> > - errno = EINVAL;
> > + if (ret != -1) {
> > + close(ret);
> > + error_setg(errp, "Unable to %s '%s' flags 0x%x: "
> > + "filesystem does not support O_DIRECT",
> > + action, name, flags);
> > + if (!errp) {
>
> If the caller ignores errors, ...
>
> > + error_report("file system does not support O_DIRECT");
>
> ... we report this error to stderr (but not any of the other ones).
> This is weird. I figure you do it here to reproduce the weirdness of
> qemu_open() before the patch. Goes back to
>
> commit a5813077aac7865f69b7ee46a594f3705429f7cd
> Author: Stefan Hajnoczi <stefanha@redhat.com>
> Date: Thu Aug 22 11:29:03 2013 +0200
>
> osdep: warn if open(O_DIRECT) on fails with EINVAL
>
> Print a warning when opening a file O_DIRECT fails with EINVAL. This
> saves users a lot of time trying to figure out the EINVAL error, which
> is typical when attempting to open a file O_DIRECT on Linux tmpfs.
>
> Reported-by: Deepak C Shetty <deepakcs@linux.vnet.ibm.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
>
> The message isn't phrased as a warning, though. Should it use
> warn_report()? Stefan?
I was really in two minds as to whether to keep this error_report or
not. It depends depends on whether any other callers of qemu_open
still need it. In fact if nothing outside the block layer uses O_DIRECT
then I think we can remove the error_report line.
> > +int qemu_open_err(const char *name, int flags, Error **errp, ...)
> > +{
> > + va_list ap;
> > + int rv;
> > +
> > + va_start(ap, errp);
> > + rv = qemu_openv(name, flags, errp, ap);
> > + va_end(ap);
> > +
> > + return rv;
> > +}
> > +
> > +int qemu_open(const char *name, int flags, ...)
> > +{
> > + va_list ap;
> > + int rv;
> > +
> > + va_start(ap, flags);
> > + rv = qemu_openv(name, flags, NULL, ap);
> > + va_end(ap);
> > +
> > + return rv;
> > +}
>
> I'd rename this to qemu_open_with_bad_error_messages().
My goal was to avoid a big bang conversion of all callers.
>
> For better ones, callers can use
>
> if (qemu_open_err(name, flags, &err) < 0) {
> error_report_err(err);
> ...
> }
>
> or, where the error is fatal
>
> qemu_open_err(name, flags, &error_fatal);
>
> If you prefer not to rename it now, please add a comment why it should
> not be used in new code, and existing uses should be converted.
>
> If you rename, call the new one qemu_open().
Maybe it is better to rename upfront though, instead of waiting till
everything uses the qemu_open_err and then renaming back to qemu_open.
Regards,
Daniel
--
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/3] util: validate whether O_DIRECT is supported after failure
2020-07-01 16:05 ` [PATCH 1/3] util: validate whether O_DIRECT is supported after failure Daniel P. Berrangé
@ 2020-07-02 10:10 ` Philippe Mathieu-Daudé
0 siblings, 0 replies; 8+ messages in thread
From: Philippe Mathieu-Daudé @ 2020-07-02 10:10 UTC (permalink / raw)
To: Daniel P. Berrangé, qemu-devel
Cc: Kevin Wolf, Max Reitz, qemu-block, P J P
On 7/1/20 6:05 PM, Daniel P. Berrangé wrote:
> Currently we suggest that a filesystem may not support O_DIRECT after
> seeing an EINVAL. Other things can cause EINVAL though, so it is better
> to do an explicit check, and then report a definitive error message.
>
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
> util/osdep.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/util/osdep.c b/util/osdep.c
> index 4829c07ff6..4bdbe81cec 100644
> --- a/util/osdep.c
> +++ b/util/osdep.c
> @@ -342,8 +342,17 @@ int qemu_open(const char *name, int flags, ...)
>
> #ifdef O_DIRECT
> if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) {
> - error_report("file system may not support O_DIRECT");
> - errno = EINVAL; /* in case it was clobbered */
> + int newflags = flags & ~O_DIRECT;
> +# ifdef O_CLOEXEC
> + ret = open(name, newflags | O_CLOEXEC, mode);
> +# else
> + ret = open(name, newflags, mode);
> +# endif
Can we use this simpler form (easier to set a breakpoint)?
#ifdef O_CLOEXEC
newflags |= O_CLOEXEC;
#endif
ret = open(name, newflags, mode);
Whichever you prefer:
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> + if (ret != -1) {
> + close(ret);
> + error_report("file system does not support O_DIRECT");
> + errno = EINVAL;
> + }
> }
> #endif /* O_DIRECT */
>
>
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2020-07-02 10:11 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-01 16:05 [PATCH 0/3] block: improve error reporting for unsupported O_DIRECT Daniel P. Berrangé
2020-07-01 16:05 ` [PATCH 1/3] util: validate whether O_DIRECT is supported after failure Daniel P. Berrangé
2020-07-02 10:10 ` Philippe Mathieu-Daudé
2020-07-01 16:05 ` [PATCH 2/3] util: support detailed error reporting for qemu_open Daniel P. Berrangé
2020-07-02 5:13 ` Markus Armbruster
2020-07-02 9:30 ` Daniel P. Berrangé
2020-07-01 16:05 ` [PATCH 3/3] block: switch to use qemu_open_err for improved errors Daniel P. Berrangé
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