From 80fc609da0904d6b8f21ef017808622567ed91b5 Mon Sep 17 00:00:00 2001 Message-Id: <80fc609da0904d6b8f21ef017808622567ed91b5.1383564115.git.minovotn@redhat.com> In-Reply-To: <5575e0aec51f40ebec46e98ec085cda053283aba.1383564115.git.minovotn@redhat.com> References: <5575e0aec51f40ebec46e98ec085cda053283aba.1383564115.git.minovotn@redhat.com> From: Tomoki Sekiyama <tsekiyam@redhat.com> Date: Tue, 15 Oct 2013 21:40:57 +0200 Subject: [PATCH 11/14] qemu-ga: execute fsfreeze-freeze in reverse order of mounts RH-Author: Tomoki Sekiyama <tsekiyam@redhat.com> Message-id: <1381873257-2800-1-git-send-email-tsekiyam@redhat.com> Patchwork-id: 54955 O-Subject: [RHEL 7.0 qemu-kvm PATCH] qemu-ga: execute fsfreeze-freeze in reverse order of mounts Bugzilla: 1019352 RH-Acked-by: Laszlo Ersek <lersek@redhat.com> RH-Acked-by: Max Reitz <mreitz@redhat.com> RH-Acked-by: Luiz Capitulino <lcapitulino@redhat.com> From: Tomoki Sekiyama <tomoki.sekiyama@hds.com> Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1019352 Brew: https://brewweb.devel.redhat.com/taskinfo?taskID=6420515 Currently, fsfreeze-freeze may cause deadlock if a guest has loopback mounts of image files in its disk; e.g.: # mount | grep ^/ /dev/vda1 / type ext4 (rw,noatime,seclabel,data=ordered) /tmp/disk.img on /mnt type ext4 (rw,relatime,seclabel) To avoid the deadlock, this freezes filesystems in reverse order of mounts. Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama@hds.com> Reviewed-by: Eric Blake <eblake@redhat.com> *fix up commit msg Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com> (cherry picked from commit e5d9adbdab972a2172815c1174aed3fabcc448f1) --- qga/commands-posix.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) Signed-off-by: Michal Novotny <minovotn@redhat.com> --- qga/commands-posix.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/qga/commands-posix.c b/qga/commands-posix.c index e199738..f453132 100644 --- a/qga/commands-posix.c +++ b/qga/commands-posix.c @@ -566,7 +566,7 @@ typedef struct FsMount { QTAILQ_ENTRY(FsMount) next; } FsMount; -typedef QTAILQ_HEAD(, FsMount) FsMountList; +typedef QTAILQ_HEAD(FsMountList, FsMount) FsMountList; static void free_fs_mount_list(FsMountList *mounts) { @@ -728,7 +728,7 @@ int64_t qmp_guest_fsfreeze_freeze(Error **err) /* cannot risk guest agent blocking itself on a write in this state */ ga_set_frozen(ga_state); - QTAILQ_FOREACH(mount, &mounts, next) { + QTAILQ_FOREACH_REVERSE(mount, &mounts, FsMountList, next) { fd = qemu_open(mount->dirname, O_RDONLY); if (fd == -1) { error_setg_errno(err, errno, "failed to open %s", mount->dirname); -- 1.7.11.7