| Message ID | 1607489688-37088-1-git-send-email-fengli@smartx.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] file-posix: detect the lock using the real file | expand |
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
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 > -- > |: 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 :| >
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;
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(-)