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From: | zhanghailiang |
Subject: | Re: [Qemu-devel] [PATCH RFC for-2.3 2/6] qga: introduce three help functions for memory block functions |
Date: | Mon, 22 Dec 2014 18:12:04 +0800 |
User-agent: | Mozilla/5.0 (Windows NT 6.1; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 |
On 2014/12/22 4:58, Michael Roth wrote:
Quoting zhanghailiang (2014-12-06 00:59:15)Signed-off-by: zhanghailiang <address@hidden> --- qga/commands-posix.c | 130 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 130 insertions(+) diff --git a/qga/commands-posix.c b/qga/commands-posix.c index b0d6a5d..8917dca 100644 --- a/qga/commands-posix.c +++ b/qga/commands-posix.c @@ -1875,6 +1875,136 @@ int64_t qmp_guest_set_vcpus(GuestLogicalProcessorList *vcpus, Error **errp) return processed; }I think these would break build bisectability. Please move these into the patches which introduce the first users.
OK, will squash patch into patch 3.
+static void ga_read_sysfs_file(int dirfd, const char *pathname, char *buf, + int size, Error **errp) +{ + int fd; + int res; + + errno = 0; + fd = openat(dirfd, pathname, O_RDONLY); + if (fd == -1) { + error_setg_errno(errp, errno, "open sysfs file \"%s\"", pathname); + return; + } + + res = pread(fd, buf, size, 0); + if (res == -1) { + error_setg_errno(errp, errno, "pread sysfs file \"%s\"", pathname); + } else if (res == 0) { + error_setg(errp, "pread sysfs file \"%s\": unexpected EOF", pathname); + } + res = close(fd); + g_assert(res == 0);This should also be propagated up as an error, killing the guest agent should be avoided when possible.
Yes, you are right. I noted that, in most cases, we ignore the return value of close() in qemu codes, so i will choose to ignore here too, is it OK?
+} + +static void ga_write_sysfs_file(int dirfd, const char *pathname, + const char *buf, int size, Error **errp) +{ + int fd; + int res; + + errno = 0; + fd = openat(dirfd, pathname, O_WRONLY); + if (fd == -1) { + error_setg_errno(errp, errno, "open sysfs file \"%s\"", pathname); + return; + } + + if (pwrite(fd, buf, size, 0) == -1) { + error_setg_errno(errp, errno, "pwrite sysfs file \"%s\"", pathname); + } + + res = close(fd); + g_assert(res == 0); +} + +/* Transfer online/offline status between @mem_blk and the guest system. + * + * On input either @errp or address@hidden must be NULL. + * + * In address@hidden direction, the following @mem_blk fields are accessed: + * - R: mem_blk->phys_index + * - W: mem_blk->online + * - W: mem_blk->can_offline + * + * In @mem_blk-to-system direction, the following @mem_blk fields are accessed: + * - R: mem_blk->phys_index + * - R: mem_blk->online + *- R: mem_blk->can_offline + * Written members remain unmodified on error. + */ +static void transfer_memory_block(GuestMemoryBlock *mem_blk, bool sys2memblk, + Error **errp) +{ + char *dirpath; + int dirfd; + int res; + char *status; + Error *local_err = NULL; + + dirpath = g_strdup_printf("/sys/devices/system/memory/memory%" PRId64 "/", + mem_blk->phys_index); + dirfd = open(dirpath, O_RDONLY | O_DIRECTORY); + if (dirfd == -1) { + error_setg_errno(errp, errno, "open(\"%s\")", dirpath); + g_free(dirpath); + return; + } + g_free(dirpath); + + status = g_malloc0(10); + ga_read_sysfs_file(dirfd, "state", status, 10, &local_err); + if (local_err) { + /* treat with sysfs file that not exist in old kernel */ + if (errno == ENOENT) { + error_free(local_err); + if (sys2memblk) { + mem_blk->online = true; + mem_blk->can_offline = false; + } else if (!mem_blk->online) { + error_setg(errp, "memory block #%" PRId64 " can't be " + "offlined", mem_blk->phys_index); + } + } else { + error_propagate(errp, local_err); + } + return;Need to free 'status' here, and close 'dirfd'. perhaps just a goto to the end of the function since you already have common cleanup there. And, if you use 'local_err' in place of 'err' for error_set, you can maybe move all your error_propagate calls there as well.
Good catch, will fix it in next version, thanks.
+ } + + if (sys2memblk) { + char removable = '0'; + + mem_blk->online = (strncmp(status, "online", 6) == 0); + + ga_read_sysfs_file(dirfd, "removable", &removable, 1, &local_err); + if (local_err) { + /* if no 'removable' file, it does't support offline mem blk */ + if (errno == ENOENT) { + error_free(local_err); + mem_blk->can_offline = false; + } else { + error_propagate(errp, local_err); + } + } else { + mem_blk->can_offline = (removable != '0'); + } + } else { + if (mem_blk->online != (strncmp(status, "online", 6) == 0)) { + char *new_state = mem_blk->online ? g_strdup("online") : + g_strdup("offline"); + + ga_write_sysfs_file(dirfd, "state", new_state, strlen(new_state), + errp); + g_free(new_state); + } /* otherwise pretend successful re-(on|off)-lining */ + } + + g_free(status); + res = close(dirfd); + g_assert(res == 0); +} + #else /* defined(__linux__) */ void qmp_guest_suspend_disk(Error **errp) -- 1.7.12.4.
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