#ifndef _GNU_SOURCE # define _GNU_SOURCE #endif #include #include #include #include #include #include #include #include #include "die.h" #include "dev.h" #include "ioops.h" #include "str.h" #include "built_in.h" int open_or_die(const char *file, int flags) { int ret = open(file, flags); if (unlikely(ret < 0)) panic("Cannot open file %s! %s.\n", file, strerror(errno)); return ret; } int open_or_die_m(const char *file, int flags, mode_t mode) { int ret = open(file, flags, mode); if (unlikely(ret < 0)) panic("Cannot open or create file %s! %s.", file, strerror(errno)); return ret; } int dup_or_die(int oldfd) { int newfd = dup(oldfd); if (unlikely(newfd < 0)) panic("Cannot dup old file descriptor!\n"); return newfd; } void dup2_or_die(int oldfd, int newfd) { int ret = dup2(oldfd, newfd); if (unlikely(ret < 0)) panic("Cannot dup2 old/new file descriptor!\n"); } void create_or_die(const char *file, mode_t mode) { int fd = open_or_die_m(file, O_WRONLY | O_CREAT, mode); close(fd); } void pipe_or_die(int pipefd[2], int flags) { int ret = pipe2(pipefd, flags); if (unlikely(ret < 0)) panic("Cannot create pipe2 event fd! %s.\n", strerror(errno)); } int tun_open_or_die(const char *name, int type) { int fd, ret; short flags; struct ifreq ifr; if (unlikely(!name)) panic("No name provided for tundev!\n"); fd = open_or_die("/dev/net/tun", O_RDWR); memset(&ifr, 0, sizeof(ifr)); ifr.ifr_flags = type; strlcpy(ifr.ifr_name, name, IFNAMSIZ); ret = ioctl(fd, TUNSETIFF, &ifr); if (unlikely(ret < 0)) panic("ioctl screwed up! %s.\n", strerror(errno)); ret = fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK); if (unlikely(ret < 0)) panic("fctnl screwed up! %s.\n", strerror(errno)); flags = device_get_flags(name); flags |= IFF_UP | IFF_RUNNING; device_set_flags(name, flags); return fd; } ssize_t read_or_die(int fd, void *buf, size_t len) { ssize_t ret = read(fd, buf, len); if (unlikely(ret < 0)) { if (errno == EPIPE) die(); panic("Cannot read from descriptor! %s.\n", strerror(errno)); } return ret; } ssize_t write_or_die(int fd, const void *buf, size_t len) { ssize_t ret = write(fd, buf, len); if (unlikely(ret < 0)) { if (errno == EPIPE) die(); panic("Cannot write to descriptor! %s.", strerror(errno)); } return ret; } int read_blob_or_die(const char *file, void *blob, size_t count) { int fd, ret; fd = open_or_die(file, O_RDONLY); ret = read_or_die(fd, blob, count); close(fd); return ret; } int write_blob_or_die(const char *file, const void *blob, size_t count) { int fd, ret; fd = open_or_die_m(file, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR); ret = write_or_die(fd, blob, count); fdatasync(fd); close(fd); return ret; } /select>
path: root/Documentation/IRQ-affinity.txt
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authorBob Liu <bob.liu@oracle.com>2016-06-07 10:43:15 -0400
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2016-06-08 13:54:39 -0400
commitefd1535270c1deb0487527bf0c3c827301a69c93 (patch)
treee0afb0ad9d8e7db1ed1d52ba4c07e2278ff2b7c4 /Documentation/IRQ-affinity.txt
parent116f7d4a21fe450efc652c4850eb27cda36c9db0 (diff)
xen-blkfront: don't call talk_to_blkback when already connected to blkback
Sometimes blkfront may twice receive blkback_changed() notification (XenbusStateConnected) after migration, which will cause talk_to_blkback() to be called twice too and confuse xen-blkback. The flow is as follow: blkfront blkback blkfront_resume() > talk_to_blkback() > Set blkfront to XenbusStateInitialised front changed() > Connect() > Set blkback to XenbusStateConnected blkback_changed() > Skip talk_to_blkback() because frontstate == XenbusStateInitialised > blkfront_connect() > Set blkfront to XenbusStateConnected ----- And here we get another XenbusStateConnected notification leading to: ----- blkback_changed() > because now frontstate != XenbusStateInitialised talk_to_blkback() is also called again > blkfront state changed from XenbusStateConnected to XenbusStateInitialised (Which is not correct!) front_changed(): > Do nothing because blkback already in XenbusStateConnected Now blkback is in XenbusStateConnected but blkfront is still in XenbusStateInitialised - leading to no disks. Poking of the XenbusStateConnected state is allowed (to deal with block disk change) and has to be dealt with. The most likely cause of this bug are custom udev scripts hooking up the disks and then validating the size. Signed-off-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'Documentation/IRQ-affinity.txt')