Commit 1f4ad7d3 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

block: Don't request I/O permission with BDRV_O_NO_IO 



'qemu-img info' makes sense even when BLK_PERM_CONSISTENT_READ cannot be
granted because of a block job in a running qemu process. It already
sets BDRV_O_NO_IO to indicate that it doesn't access the guest visible
data at all.

Check the BDRV_O_NO_IO flags in blk_new_open(), so that I/O related
permissions are not unnecessarily requested and 'qemu-img info' can work
even if BLK_PERM_CONSISTENT_READ cannot be granted.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
Reviewed-by: default avatarFam Zheng <famz@redhat.com>
Reviewed-by: default avatarAlberto Garcia <berto@igalia.com>
parent dacaa162

block/block-backend.c

+6 −4
Original line number Original line Diff line number Diff line
@@ -299,7 +299,7 @@ BlockBackend *blk_new_open(const char *filename, const char *reference, 
{

{

    BlockBackend *blk;

    BlockBackend *blk;

    BlockDriverState *bs;

    BlockDriverState *bs;

    uint64_t perm;

    uint64_t perm = 0;





    /* blk_new_open() is mainly used in .bdrv_create implementations and the

    /* blk_new_open() is mainly used in .bdrv_create implementations and the

     * tools where sharing isn't a concern because the BDS stays private, so we

     * tools where sharing isn't a concern because the BDS stays private, so we
@@ -309,10 +309,12 @@ BlockBackend *blk_new_open(const char *filename, const char *reference, 
     * caller of blk_new_open() doesn't make use of the permissions, but they

     * caller of blk_new_open() doesn't make use of the permissions, but they

     * shouldn't hurt either. We can still share everything here because the

     * shouldn't hurt either. We can still share everything here because the

     * guest devices will add their own blockers if they can't share. */

     * guest devices will add their own blockers if they can't share. */

    perm = BLK_PERM_CONSISTENT_READ;

    if ((flags & BDRV_O_NO_IO) == 0) {

        perm |= BLK_PERM_CONSISTENT_READ;

        if (flags & BDRV_O_RDWR) {

        if (flags & BDRV_O_RDWR) {

            perm |= BLK_PERM_WRITE;

            perm |= BLK_PERM_WRITE;

        }

        }

    }

    if (flags & BDRV_O_RESIZE) {

    if (flags & BDRV_O_RESIZE) {

        perm |= BLK_PERM_RESIZE;

        perm |= BLK_PERM_RESIZE;

    }

    }