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Re: [Qemu-devel] [PATCH 4/5] Reopen files after migration
From: |
Blue Swirl |
Subject: |
Re: [Qemu-devel] [PATCH 4/5] Reopen files after migration |
Date: |
Tue, 4 Jan 2011 19:05:44 +0000 |
On Tue, Jan 4, 2011 at 2:33 PM, Juan Quintela <address@hidden> wrote:
> We need to invalidate the Read Cache on the destination, otherwise we
> have corruption. Easy way to reproduce it is:
>
> - create an qcow2 images
> - start qemu on destination of migration (qemu .... -incoming tcp:...)
> - start qemu on source of migration and do one install.
> - migrate at the end of install (when lot of disk IO has happened).
>
> Destination of migration has a local copy of the L1/L2 tables that existed
> at the beginning, before the install started. We have disk corruption at
> this point. The solution (for NFS) is to just re-open the file. Operations
> have to happen in this order:
>
> - source of migration: flush()
> - destination: close(file);
> - destination: open(file)
>
> it is not necesary that source of migration close the file.
>
> Signed-off-by: Juan Quintela <address@hidden>
> ---
> blockdev.c | 42 +++++++++++++++++++++++++++++++++++++-----
> blockdev.h | 6 ++++++
> migration.c | 6 ++++++
> 3 files changed, 49 insertions(+), 5 deletions(-)
>
> diff --git a/blockdev.c b/blockdev.c
> index f9bb659..3f3df7a 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -116,6 +116,7 @@ void drive_uninit(DriveInfo *dinfo)
> bdrv_delete(dinfo->bdrv);
> QTAILQ_REMOVE(&drives, dinfo, next);
> qemu_free(dinfo->id);
> + qemu_free(dinfo->file);
> qemu_free(dinfo);
> }
>
> @@ -136,6 +137,36 @@ static int parse_block_error_action(const char *buf, int
> is_read)
> }
> }
>
> +static int drive_open(DriveInfo *dinfo)
> +{
> + int res = bdrv_open(dinfo->bdrv, dinfo->file, dinfo->bdrv_flags,
> dinfo->drv);
> +
> + if (res < 0) {
> + fprintf(stderr, "qemu: could not open disk image %s: %s\n",
> + dinfo->file, strerror(errno));
> + }
> + return res;
> +}
> +
> +int drives_reinit(void)
> +{
> + DriveInfo *dinfo;
> +
> + QTAILQ_FOREACH(dinfo, &drives, next) {
> + if (dinfo->opened && !bdrv_is_read_only(dinfo->bdrv)) {
> + int res;
> + bdrv_close(dinfo->bdrv);
> + res = drive_open(dinfo);
> + if (res) {
> + fprintf(stderr, "qemu: re-open of %s failed wth error
> %d\n",
> + dinfo->file, res);
> + return res;
> + }
> + }
> + }
> + return 0;
> +}
> +
> DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi, int *fatal_error)
> {
> const char *buf;
> @@ -156,7 +187,6 @@ DriveInfo *drive_init(QemuOpts *opts, int
> default_to_scsi, int *fatal_error)
> const char *devaddr;
> DriveInfo *dinfo;
> int snapshot = 0;
> - int ret;
>
> *fatal_error = 1;
>
> @@ -487,10 +517,12 @@ DriveInfo *drive_init(QemuOpts *opts, int
> default_to_scsi, int *fatal_error)
>
> bdrv_flags |= ro ? 0 : BDRV_O_RDWR;
>
> - ret = bdrv_open(dinfo->bdrv, file, bdrv_flags, drv);
> - if (ret < 0) {
> - fprintf(stderr, "qemu: could not open disk image %s: %s\n",
> - file, strerror(-ret));
> + dinfo->file = qemu_strdup(file);
> + dinfo->bdrv_flags = bdrv_flags;
> + dinfo->drv = drv;
> + dinfo->opened = 1;
> +
> + if (drive_open(dinfo) < 0) {
> goto error;
> }
>
> diff --git a/blockdev.h b/blockdev.h
> index 4536b5c..e009fee 100644
> --- a/blockdev.h
> +++ b/blockdev.h
> @@ -29,6 +29,10 @@ struct DriveInfo {
> QemuOpts *opts;
> char serial[BLOCK_SERIAL_STRLEN + 1];
> QTAILQ_ENTRY(DriveInfo) next;
> + int opened;
> + int bdrv_flags;
> + char *file;
> + BlockDriver *drv;
> };
>
> #define MAX_IDE_DEVS 2
> @@ -42,6 +46,8 @@ DriveInfo *drive_get_by_blockdev(BlockDriverState *bs);
> QemuOpts *drive_add(const char *file, const char *fmt, ...) GCC_FMT_ATTR(2,
> 3);
> DriveInfo *drive_init(QemuOpts *arg, int default_to_scsi, int *fatal_error);
>
> +extern int drives_reinit(void);
'extern' is useless for functions.
- [Qemu-devel] [PATCH 0/5] Fix migration with NFS & iscsi/Fiber channel, Juan Quintela, 2011/01/04
- [Qemu-devel] [PATCH 2/5] blockdev: don't leak id on removal, Juan Quintela, 2011/01/04
- [Qemu-devel] [PATCH 3/5] blockdev: release resources in the error case, Juan Quintela, 2011/01/04
- [Qemu-devel] [PATCH 4/5] Reopen files after migration, Juan Quintela, 2011/01/04
- [Qemu-devel] [PATCH 5/5] drive_open: Add invalidate option for block devices, Juan Quintela, 2011/01/04
- [Qemu-devel] [PATCH 1/5] migration: exit with error code, Juan Quintela, 2011/01/04
- [Qemu-devel] Re: [PATCH 0/5] Fix migration with NFS & iscsi/Fiber channel, Juan Quintela, 2011/01/10