block/file-posix.c | 32 ++++++++++++++++++-------------- include/qemu/osdep.h | 2 +- tests/test-image-locking.c | 2 +- util/osdep.c | 19 ++++++++++++------- 4 files changed, 32 insertions(+), 23 deletions(-)
This patch addresses this issue:
When accessing a volume on an NFS filesystem without supporting the file lock,
tools, like qemu-img, will complain "Failed to lock byte 100".
In the original code, the qemu_has_ofd_lock will test the lock on the
"/dev/null" pseudo-file. Actually, the file.locking is per-drive property,
which depends on the underlay filesystem.
In this patch, make the 'qemu_has_ofd_lock' with a filename be more
generic and reasonable.
Signed-off-by: Li Feng <fengli@smartx.com>
---
v2: remove the refactoring.
---
block/file-posix.c | 32 ++++++++++++++++++--------------
include/qemu/osdep.h | 2 +-
tests/test-image-locking.c | 2 +-
util/osdep.c | 19 ++++++++++++-------
4 files changed, 32 insertions(+), 23 deletions(-)
diff --git a/block/file-posix.c b/block/file-posix.c
index 806764f7e3..03be1b188c 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -595,7 +595,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
switch (locking) {
case ON_OFF_AUTO_ON:
s->use_lock = true;
- if (!qemu_has_ofd_lock()) {
+ if (!qemu_has_ofd_lock(filename)) {
warn_report("File lock requested but OFD locking syscall is "
"unavailable, falling back to POSIX file locks");
error_printf("Due to the implementation, locks can be lost "
@@ -606,7 +606,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
s->use_lock = false;
break;
case ON_OFF_AUTO_AUTO:
- s->use_lock = qemu_has_ofd_lock();
+ s->use_lock = qemu_has_ofd_lock(filename);
break;
default:
abort();
@@ -2388,6 +2388,7 @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)
int fd;
uint64_t perm, shared;
int result = 0;
+ bool use_lock;
/* Validate options and set default values */
assert(options->driver == BLOCKDEV_DRIVER_FILE);
@@ -2428,19 +2429,22 @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)
perm = BLK_PERM_WRITE | BLK_PERM_RESIZE;
shared = BLK_PERM_ALL & ~BLK_PERM_RESIZE;
- /* Step one: Take locks */
- result = raw_apply_lock_bytes(NULL, fd, perm, ~shared, false, errp);
- if (result < 0) {
- goto out_close;
- }
+ use_lock = qemu_has_ofd_lock(file_opts->filename);
+ if (use_lock) {
+ /* Step one: Take locks */
+ result = raw_apply_lock_bytes(NULL, fd, perm, ~shared, false, errp);
+ if (result < 0) {
+ goto out_close;
+ }
- /* Step two: Check that nobody else has taken conflicting locks */
- result = raw_check_lock_bytes(fd, perm, shared, errp);
- if (result < 0) {
- error_append_hint(errp,
- "Is another process using the image [%s]?\n",
- file_opts->filename);
- goto out_unlock;
+ /* Step two: Check that nobody else has taken conflicting locks */
+ result = raw_check_lock_bytes(fd, perm, shared, errp);
+ if (result < 0) {
+ error_append_hint(errp,
+ "Is another process using the image [%s]?\n",
+ file_opts->filename);
+ goto out_unlock;
+ }
}
/* Clear the file by truncating it to 0 */
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index f9ec8c84e9..349adad465 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -512,7 +512,7 @@ int qemu_dup(int fd);
int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive);
int qemu_unlock_fd(int fd, int64_t start, int64_t len);
int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive);
-bool qemu_has_ofd_lock(void);
+bool qemu_has_ofd_lock(const char *filename);
#endif
#if defined(__HAIKU__) && defined(__i386__)
diff --git a/tests/test-image-locking.c b/tests/test-image-locking.c
index ba057bd66c..3e80246081 100644
--- a/tests/test-image-locking.c
+++ b/tests/test-image-locking.c
@@ -149,7 +149,7 @@ int main(int argc, char **argv)
g_test_init(&argc, &argv, NULL);
- if (qemu_has_ofd_lock()) {
+ if (qemu_has_ofd_lock(NULL)) {
g_test_add_func("/image-locking/basic", test_image_locking_basic);
g_test_add_func("/image-locking/set-perm-abort", test_set_perm_abort);
}
diff --git a/util/osdep.c b/util/osdep.c
index 66d01b9160..20119aa9ae 100644
--- a/util/osdep.c
+++ b/util/osdep.c
@@ -187,7 +187,7 @@ static int qemu_parse_fdset(const char *param)
return qemu_parse_fd(param);
}
-static void qemu_probe_lock_ops(void)
+static void qemu_probe_lock_ops(const char *filename)
{
if (fcntl_op_setlk == -1) {
#ifdef F_OFD_SETLK
@@ -200,10 +200,15 @@ static void qemu_probe_lock_ops(void)
.l_type = F_WRLCK,
};
- fd = open("/dev/null", O_RDWR);
+ if (filename) {
+ fd = open(filename, O_RDWR);
+ } else {
+ fd = open("/dev/null", O_RDONLY);
+ }
if (fd < 0) {
fprintf(stderr,
- "Failed to open /dev/null for OFD lock probing: %s\n",
+ "Failed to open %s for OFD lock probing: %s\n",
+ filename ? filename : "/dev/null",
strerror(errno));
fcntl_op_setlk = F_SETLK;
fcntl_op_getlk = F_GETLK;
@@ -225,9 +230,9 @@ static void qemu_probe_lock_ops(void)
}
}
-bool qemu_has_ofd_lock(void)
+bool qemu_has_ofd_lock(const char *filename)
{
- qemu_probe_lock_ops();
+ qemu_probe_lock_ops(filename);
#ifdef F_OFD_SETLK
return fcntl_op_setlk == F_OFD_SETLK;
#else
@@ -244,7 +249,7 @@ static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type)
.l_len = len,
.l_type = fl_type,
};
- qemu_probe_lock_ops();
+ qemu_probe_lock_ops(NULL);
do {
ret = fcntl(fd, fcntl_op_setlk, &fl);
} while (ret == -1 && errno == EINTR);
@@ -270,7 +275,7 @@ int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive)
.l_len = len,
.l_type = exclusive ? F_WRLCK : F_RDLCK,
};
- qemu_probe_lock_ops();
+ qemu_probe_lock_ops(NULL);
ret = fcntl(fd, fcntl_op_getlk, &fl);
if (ret == -1) {
return -errno;
--
2.24.3
On Wed, Dec 09, 2020 at 12:54:48PM +0800, Li Feng wrote:
> This patch addresses this issue:
> When accessing a volume on an NFS filesystem without supporting the file lock,
> tools, like qemu-img, will complain "Failed to lock byte 100".
>
> In the original code, the qemu_has_ofd_lock will test the lock on the
> "/dev/null" pseudo-file. Actually, the file.locking is per-drive property,
> which depends on the underlay filesystem.
>
> In this patch, make the 'qemu_has_ofd_lock' with a filename be more
> generic and reasonable.
>
> Signed-off-by: Li Feng <fengli@smartx.com>
> ---
> v2: remove the refactoring.
> ---
> block/file-posix.c | 32 ++++++++++++++++++--------------
> include/qemu/osdep.h | 2 +-
> tests/test-image-locking.c | 2 +-
> util/osdep.c | 19 ++++++++++++-------
> 4 files changed, 32 insertions(+), 23 deletions(-)
>
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 806764f7e3..03be1b188c 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -595,7 +595,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
> switch (locking) {
> case ON_OFF_AUTO_ON:
> s->use_lock = true;
> - if (!qemu_has_ofd_lock()) {
> + if (!qemu_has_ofd_lock(filename)) {
> warn_report("File lock requested but OFD locking syscall is "
> "unavailable, falling back to POSIX file locks");
> error_printf("Due to the implementation, locks can be lost "
> @@ -606,7 +606,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
> s->use_lock = false;
> break;
> case ON_OFF_AUTO_AUTO:
> - s->use_lock = qemu_has_ofd_lock();
> + s->use_lock = qemu_has_ofd_lock(filename);
> break;
> default:
> abort();
> @@ -2388,6 +2388,7 @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)
> int fd;
> uint64_t perm, shared;
> int result = 0;
> + bool use_lock;
>
> /* Validate options and set default values */
> assert(options->driver == BLOCKDEV_DRIVER_FILE);
> @@ -2428,19 +2429,22 @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)
> perm = BLK_PERM_WRITE | BLK_PERM_RESIZE;
> shared = BLK_PERM_ALL & ~BLK_PERM_RESIZE;
>
> - /* Step one: Take locks */
> - result = raw_apply_lock_bytes(NULL, fd, perm, ~shared, false, errp);
> - if (result < 0) {
> - goto out_close;
> - }
> + use_lock = qemu_has_ofd_lock(file_opts->filename);
> + if (use_lock) {
> + /* Step one: Take locks */
> + result = raw_apply_lock_bytes(NULL, fd, perm, ~shared, false, errp);
> + if (result < 0) {
> + goto out_close;
> + }
>
> - /* Step two: Check that nobody else has taken conflicting locks */
> - result = raw_check_lock_bytes(fd, perm, shared, errp);
> - if (result < 0) {
> - error_append_hint(errp,
> - "Is another process using the image [%s]?\n",
> - file_opts->filename);
> - goto out_unlock;
> + /* Step two: Check that nobody else has taken conflicting locks */
> + result = raw_check_lock_bytes(fd, perm, shared, errp);
> + if (result < 0) {
> + error_append_hint(errp,
> + "Is another process using the image [%s]?\n",
> + file_opts->filename);
> + goto out_unlock;
> + }
> }
>
> /* Clear the file by truncating it to 0 */
> diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> index f9ec8c84e9..349adad465 100644
> --- a/include/qemu/osdep.h
> +++ b/include/qemu/osdep.h
> @@ -512,7 +512,7 @@ int qemu_dup(int fd);
> int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive);
> int qemu_unlock_fd(int fd, int64_t start, int64_t len);
> int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive);
> -bool qemu_has_ofd_lock(void);
> +bool qemu_has_ofd_lock(const char *filename);
> #endif
>
> #if defined(__HAIKU__) && defined(__i386__)
> diff --git a/tests/test-image-locking.c b/tests/test-image-locking.c
> index ba057bd66c..3e80246081 100644
> --- a/tests/test-image-locking.c
> +++ b/tests/test-image-locking.c
> @@ -149,7 +149,7 @@ int main(int argc, char **argv)
>
> g_test_init(&argc, &argv, NULL);
>
> - if (qemu_has_ofd_lock()) {
> + if (qemu_has_ofd_lock(NULL)) {
> g_test_add_func("/image-locking/basic", test_image_locking_basic);
> g_test_add_func("/image-locking/set-perm-abort", test_set_perm_abort);
> }
> diff --git a/util/osdep.c b/util/osdep.c
> index 66d01b9160..20119aa9ae 100644
> --- a/util/osdep.c
> +++ b/util/osdep.c
> @@ -187,7 +187,7 @@ static int qemu_parse_fdset(const char *param)
> return qemu_parse_fd(param);
> }
>
> -static void qemu_probe_lock_ops(void)
> +static void qemu_probe_lock_ops(const char *filename)
> {
> if (fcntl_op_setlk == -1) {
> #ifdef F_OFD_SETLK
> @@ -200,10 +200,15 @@ static void qemu_probe_lock_ops(void)
> .l_type = F_WRLCK,
> };
>
> - fd = open("/dev/null", O_RDWR);
> + if (filename) {
> + fd = open(filename, O_RDWR);
> + } else {
> + fd = open("/dev/null", O_RDONLY);
> + }
> if (fd < 0) {
> fprintf(stderr,
> - "Failed to open /dev/null for OFD lock probing: %s\n",
> + "Failed to open %s for OFD lock probing: %s\n",
> + filename ? filename : "/dev/null",
> strerror(errno));
> fcntl_op_setlk = F_SETLK;
> fcntl_op_getlk = F_GETLK;
This is still just as broken as v1, because it is setting
a global variable fcntl_op_getlk, based on result of an
operation whose result will vary depending on the filename
parameter.
If you want to test whether a filesystem supports fcntl
locks in general, don't touch qemu_has_ofd_lock or
qemu_probe_lock_ops methods at all. Those are just for
probing regular fcntl vs OFD fcntl locks.
> @@ -225,9 +230,9 @@ static void qemu_probe_lock_ops(void)
> }
> }
>
> -bool qemu_has_ofd_lock(void)
> +bool qemu_has_ofd_lock(const char *filename)
> {
> - qemu_probe_lock_ops();
> + qemu_probe_lock_ops(filename);
> #ifdef F_OFD_SETLK
> return fcntl_op_setlk == F_OFD_SETLK;
> #else
> @@ -244,7 +249,7 @@ static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type)
> .l_len = len,
> .l_type = fl_type,
> };
> - qemu_probe_lock_ops();
> + qemu_probe_lock_ops(NULL);
> do {
> ret = fcntl(fd, fcntl_op_setlk, &fl);
> } while (ret == -1 && errno == EINTR);
> @@ -270,7 +275,7 @@ int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive)
> .l_len = len,
> .l_type = exclusive ? F_WRLCK : F_RDLCK,
> };
> - qemu_probe_lock_ops();
> + qemu_probe_lock_ops(NULL);
> ret = fcntl(fd, fcntl_op_getlk, &fl);
> if (ret == -1) {
> return -errno;
> --
> 2.24.3
>
>
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
Ok, I see.
I will split the detect lock without changing the global variable to a
separate function.
Don't call the qemu_has_ofd_lock.
Thanks.
Daniel P. Berrangé <berrange@redhat.com> 于2020年12月10日周四 下午11:59写道：
>
> On Wed, Dec 09, 2020 at 12:54:48PM +0800, Li Feng wrote:
> > This patch addresses this issue:
> > When accessing a volume on an NFS filesystem without supporting the file lock,
> > tools, like qemu-img, will complain "Failed to lock byte 100".
> >
> > In the original code, the qemu_has_ofd_lock will test the lock on the
> > "/dev/null" pseudo-file. Actually, the file.locking is per-drive property,
> > which depends on the underlay filesystem.
> >
> > In this patch, make the 'qemu_has_ofd_lock' with a filename be more
> > generic and reasonable.
> >
> > Signed-off-by: Li Feng <fengli@smartx.com>
> > ---
> > v2: remove the refactoring.
> > ---
> > block/file-posix.c | 32 ++++++++++++++++++--------------
> > include/qemu/osdep.h | 2 +-
> > tests/test-image-locking.c | 2 +-
> > util/osdep.c | 19 ++++++++++++-------
> > 4 files changed, 32 insertions(+), 23 deletions(-)
> >
> > diff --git a/block/file-posix.c b/block/file-posix.c
> > index 806764f7e3..03be1b188c 100644
> > --- a/block/file-posix.c
> > +++ b/block/file-posix.c
> > @@ -595,7 +595,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
> > switch (locking) {
> > case ON_OFF_AUTO_ON:
> > s->use_lock = true;
> > - if (!qemu_has_ofd_lock()) {
> > + if (!qemu_has_ofd_lock(filename)) {
> > warn_report("File lock requested but OFD locking syscall is "
> > "unavailable, falling back to POSIX file locks");
> > error_printf("Due to the implementation, locks can be lost "
> > @@ -606,7 +606,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
> > s->use_lock = false;
> > break;
> > case ON_OFF_AUTO_AUTO:
> > - s->use_lock = qemu_has_ofd_lock();
> > + s->use_lock = qemu_has_ofd_lock(filename);
> > break;
> > default:
> > abort();
> > @@ -2388,6 +2388,7 @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)
> > int fd;
> > uint64_t perm, shared;
> > int result = 0;
> > + bool use_lock;
> >
> > /* Validate options and set default values */
> > assert(options->driver == BLOCKDEV_DRIVER_FILE);
> > @@ -2428,19 +2429,22 @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)
> > perm = BLK_PERM_WRITE | BLK_PERM_RESIZE;
> > shared = BLK_PERM_ALL & ~BLK_PERM_RESIZE;
> >
> > - /* Step one: Take locks */
> > - result = raw_apply_lock_bytes(NULL, fd, perm, ~shared, false, errp);
> > - if (result < 0) {
> > - goto out_close;
> > - }
> > + use_lock = qemu_has_ofd_lock(file_opts->filename);
> > + if (use_lock) {
> > + /* Step one: Take locks */
> > + result = raw_apply_lock_bytes(NULL, fd, perm, ~shared, false, errp);
> > + if (result < 0) {
> > + goto out_close;
> > + }
> >
> > - /* Step two: Check that nobody else has taken conflicting locks */
> > - result = raw_check_lock_bytes(fd, perm, shared, errp);
> > - if (result < 0) {
> > - error_append_hint(errp,
> > - "Is another process using the image [%s]?\n",
> > - file_opts->filename);
> > - goto out_unlock;
> > + /* Step two: Check that nobody else has taken conflicting locks */
> > + result = raw_check_lock_bytes(fd, perm, shared, errp);
> > + if (result < 0) {
> > + error_append_hint(errp,
> > + "Is another process using the image [%s]?\n",
> > + file_opts->filename);
> > + goto out_unlock;
> > + }
> > }
> >
> > /* Clear the file by truncating it to 0 */
> > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> > index f9ec8c84e9..349adad465 100644
> > --- a/include/qemu/osdep.h
> > +++ b/include/qemu/osdep.h
> > @@ -512,7 +512,7 @@ int qemu_dup(int fd);
> > int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive);
> > int qemu_unlock_fd(int fd, int64_t start, int64_t len);
> > int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive);
> > -bool qemu_has_ofd_lock(void);
> > +bool qemu_has_ofd_lock(const char *filename);
> > #endif
> >
> > #if defined(__HAIKU__) && defined(__i386__)
> > diff --git a/tests/test-image-locking.c b/tests/test-image-locking.c
> > index ba057bd66c..3e80246081 100644
> > --- a/tests/test-image-locking.c
> > +++ b/tests/test-image-locking.c
> > @@ -149,7 +149,7 @@ int main(int argc, char **argv)
> >
> > g_test_init(&argc, &argv, NULL);
> >
> > - if (qemu_has_ofd_lock()) {
> > + if (qemu_has_ofd_lock(NULL)) {
> > g_test_add_func("/image-locking/basic", test_image_locking_basic);
> > g_test_add_func("/image-locking/set-perm-abort", test_set_perm_abort);
> > }
> > diff --git a/util/osdep.c b/util/osdep.c
> > index 66d01b9160..20119aa9ae 100644
> > --- a/util/osdep.c
> > +++ b/util/osdep.c
> > @@ -187,7 +187,7 @@ static int qemu_parse_fdset(const char *param)
> > return qemu_parse_fd(param);
> > }
> >
> > -static void qemu_probe_lock_ops(void)
> > +static void qemu_probe_lock_ops(const char *filename)
> > {
> > if (fcntl_op_setlk == -1) {
> > #ifdef F_OFD_SETLK
> > @@ -200,10 +200,15 @@ static void qemu_probe_lock_ops(void)
> > .l_type = F_WRLCK,
> > };
> >
> > - fd = open("/dev/null", O_RDWR);
> > + if (filename) {
> > + fd = open(filename, O_RDWR);
> > + } else {
> > + fd = open("/dev/null", O_RDONLY);
> > + }
> > if (fd < 0) {
> > fprintf(stderr,
> > - "Failed to open /dev/null for OFD lock probing: %s\n",
> > + "Failed to open %s for OFD lock probing: %s\n",
> > + filename ? filename : "/dev/null",
> > strerror(errno));
> > fcntl_op_setlk = F_SETLK;
> > fcntl_op_getlk = F_GETLK;
>
> This is still just as broken as v1, because it is setting
> a global variable fcntl_op_getlk, based on result of an
> operation whose result will vary depending on the filename
> parameter.
>
>
> If you want to test whether a filesystem supports fcntl
> locks in general, don't touch qemu_has_ofd_lock or
> qemu_probe_lock_ops methods at all. Those are just for
> probing regular fcntl vs OFD fcntl locks.
>
>
>
> > @@ -225,9 +230,9 @@ static void qemu_probe_lock_ops(void)
> > }
> > }
> >
> > -bool qemu_has_ofd_lock(void)
> > +bool qemu_has_ofd_lock(const char *filename)
> > {
> > - qemu_probe_lock_ops();
> > + qemu_probe_lock_ops(filename);
> > #ifdef F_OFD_SETLK
> > return fcntl_op_setlk == F_OFD_SETLK;
> > #else
> > @@ -244,7 +249,7 @@ static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type)
> > .l_len = len,
> > .l_type = fl_type,
> > };
> > - qemu_probe_lock_ops();
> > + qemu_probe_lock_ops(NULL);
> > do {
> > ret = fcntl(fd, fcntl_op_setlk, &fl);
> > } while (ret == -1 && errno == EINTR);
> > @@ -270,7 +275,7 @@ int qemu_lock_fd_test(int fd, int64_t start, int64_t len, bool exclusive)
> > .l_len = len,
> > .l_type = exclusive ? F_WRLCK : F_RDLCK,
> > };
> > - qemu_probe_lock_ops();
> > + qemu_probe_lock_ops(NULL);
> > ret = fcntl(fd, fcntl_op_getlk, &fl);
> > if (ret == -1) {
> > return -errno;
> > --
> > 2.24.3
> >
> >
>
> Regards,
> Daniel
> --
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