Commit e5d9adbd authored by Tomoki Sekiyama's avatar Tomoki Sekiyama Committed by Michael Roth
Browse files

qemu-ga: execute fsfreeze-freeze in reverse order of mounts 



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: default avatarTomoki Sekiyama <tomoki.sekiyama@hds.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
*fix up commit msg
Signed-off-by: default avatarMichael Roth <mdroth@linux.vnet.ibm.com>
parent f2c6bcfc

qga/commands-posix.c

+2 −2
Original line number Diff line number Diff line
@@ -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);