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 <fen...@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
