Commit e8877497 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Kevin Wolf
Browse files

block: handle -EBUSY in bdrv_commit_all() 



Monitor operations that manipulate image files must not execute while a
background job (like image streaming) is in progress.  This prevents
corruptions from happening when two pieces of code are manipulating the
image file without knowledge of each other.

The monitor "commit" command raises QERR_DEVICE_IN_USE when
bdrv_commit() returns -EBUSY but "commit all" has no error handling.
This is easy to fix, although note that we do not deliver a detailed
error about which device was busy in the "commit all" case.

Suggested-by: default avatarKevin Wolf <kwolf@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 3cce16f4

block.c

+6 −2
Original line number Diff line number Diff line
@@ -1244,14 +1244,18 @@ ro_cleanup: 
    return ret;

}



void bdrv_commit_all(void)

int bdrv_commit_all(void)

{

    BlockDriverState *bs;



    QTAILQ_FOREACH(bs, &bdrv_states, list) {

        bdrv_commit(bs);

        int ret = bdrv_commit(bs);

        if (ret < 0) {

            return ret;

        }

    }

    return 0;

}



struct BdrvTrackedRequest {

    BlockDriverState *bs;

block.h

+1 −1
Original line number Diff line number Diff line
@@ -165,7 +165,7 @@ int64_t bdrv_get_allocated_file_size(BlockDriverState *bs); 
void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);

void bdrv_guess_geometry(BlockDriverState *bs, int *pcyls, int *pheads, int *psecs);

int bdrv_commit(BlockDriverState *bs);

void bdrv_commit_all(void);

int bdrv_commit_all(void);

int bdrv_change_backing_file(BlockDriverState *bs,

    const char *backing_file, const char *backing_fmt);

void bdrv_register(BlockDriver *bdrv);

blockdev.c

+6 −3
Original line number Diff line number Diff line
@@ -627,12 +627,15 @@ void do_commit(Monitor *mon, const QDict *qdict) 
{

    const char *device = qdict_get_str(qdict, "device");

    BlockDriverState *bs;

    int ret;



    if (!strcmp(device, "all")) {

        bdrv_commit_all();

        ret = bdrv_commit_all();

        if (ret == -EBUSY) {

            qerror_report(QERR_DEVICE_IN_USE, device);

            return;

        }

    } else {

        int ret;



        bs = bdrv_find(device);

        if (!bs) {

            qerror_report(QERR_DEVICE_NOT_FOUND, device);