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[Qemu-devel] [PATCH v8 04/36] osdep: Add qemu_lock_fd and qemu_unlock_fd
From: |
Fam Zheng |
Subject: |
[Qemu-devel] [PATCH v8 04/36] osdep: Add qemu_lock_fd and qemu_unlock_fd |
Date: |
Fri, 30 Sep 2016 20:09:34 +0800 |
They are wrappers of POSIX fcntl "file private locking".
Signed-off-by: Fam Zheng <address@hidden>
---
include/qemu/osdep.h | 2 ++
util/osdep.c | 29 +++++++++++++++++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 9e9fa61..f773f49 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -286,6 +286,8 @@ int qemu_close(int fd);
#ifndef _WIN32
int qemu_dup(int fd);
#endif
+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);
#if defined(__HAIKU__) && defined(__i386__)
#define FMT_pid "%ld"
diff --git a/util/osdep.c b/util/osdep.c
index 06fb1cf..b85a490 100644
--- a/util/osdep.c
+++ b/util/osdep.c
@@ -140,6 +140,35 @@ static int qemu_parse_fdset(const char *param)
{
return qemu_parse_fd(param);
}
+
+static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type)
+{
+#ifdef F_OFD_SETLK
+ int ret;
+ struct flock fl = {
+ .l_whence = SEEK_SET,
+ .l_start = start,
+ .l_len = len,
+ .l_type = fl_type,
+ };
+ do {
+ ret = fcntl(fd, F_OFD_SETLK, &fl);
+ } while (ret == -1 && errno == EINTR);
+ return ret == -1 ? -errno : 0;
+#else
+ return -ENOTSUP;
+#endif
+}
+
+int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive)
+{
+ return qemu_lock_fcntl(fd, start, len, exclusive ? F_WRLCK : F_RDLCK);
+}
+
+int qemu_unlock_fd(int fd, int64_t start, int64_t len)
+{
+ return qemu_lock_fcntl(fd, start, len, F_UNLCK);
+}
#endif
/*
--
2.7.4
- [Qemu-devel] [PATCH v8 00/36] block: Image locking series, Fam Zheng, 2016/09/30
- [Qemu-devel] [PATCH v8 01/36] block: Add flag bits for image locking, Fam Zheng, 2016/09/30
- [Qemu-devel] [PATCH v8 02/36] qapi: Add ImageLockMode, Fam Zheng, 2016/09/30
- [Qemu-devel] [PATCH v8 03/36] block: Introduce image file locking, Fam Zheng, 2016/09/30
- [Qemu-devel] [PATCH v8 04/36] osdep: Add qemu_lock_fd and qemu_unlock_fd,
Fam Zheng <=
- [Qemu-devel] [PATCH v8 06/36] qemu-io: Add "-L" option for BDRV_O_NO_LOCK, Fam Zheng, 2016/09/30
- [Qemu-devel] [PATCH v8 05/36] raw-posix: Add image locking support, Fam Zheng, 2016/09/30
- [Qemu-devel] [PATCH v8 08/36] qemu-img: Update documentation of "-L" option, Fam Zheng, 2016/09/30
- [Qemu-devel] [PATCH v8 07/36] qemu-img: Add "-L" option to sub commands, Fam Zheng, 2016/09/30
- [Qemu-devel] [PATCH v8 10/36] block: Don't lock drive-backup target image in none mode, Fam Zheng, 2016/09/30
- [Qemu-devel] [PATCH v8 09/36] qemu-nbd: Add "--no-lock/-L" option, Fam Zheng, 2016/09/30
- [Qemu-devel] [PATCH v8 11/36] block: Add blk_lock_image, Fam Zheng, 2016/09/30
- [Qemu-devel] [PATCH v8 12/36] virtio-blk: Apply lock-mode when realize, Fam Zheng, 2016/09/30
- [Qemu-devel] [PATCH v8 13/36] scsi-disk: Apply lock-mode when realize, Fam Zheng, 2016/09/30
- [Qemu-devel] [PATCH v8 14/36] scsi-generic: Apply lock-mode when realize, Fam Zheng, 2016/09/30