Commit be028adc authored by Jeff Cody's avatar Jeff Cody Committed by Kevin Wolf
Browse files

block: correctly set the keep_read_only flag 



I believe the bs->keep_read_only flag is supposed to reflect
the initial open state of the device. If the device is initially
opened R/O, then commit operations, or reopen operations changing
to R/W, are prohibited.

Currently, the keep_read_only flag is only accurate for the active
layer, and its backing file. Subsequent images end up always having
the keep_read_only flag set.

For instance, what happens now:

[  base  ]  kro = 1, ro = 1
    |
    v
[ snap-1 ]  kro = 1, ro = 1
    |
    v
[ snap-2 ]  kro = 0, ro = 1
    |
    v
[ active ]  kro = 0, ro = 0

What we want:

[  base  ]  kro = 0, ro = 1
    |
    v
[ snap-1 ]  kro = 0, ro = 1
    |
    v
[ snap-2 ]  kro = 0, ro = 1
    |
    v
[ active ]  kro = 0, ro = 0

Signed-off-by: default avatarJeff Cody <jcody@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 80dd1aae

block.c

+7 −7
Original line number Diff line number Diff line
@@ -668,7 +668,7 @@ static int bdrv_open_common(BlockDriverState *bs, const char *filename, 
        open_flags |= BDRV_O_RDWR;

    }



    bs->keep_read_only = bs->read_only = !(open_flags & BDRV_O_RDWR);

    bs->read_only = !(open_flags & BDRV_O_RDWR);



    /* Open the image, either directly or using a protocol */

    if (drv->bdrv_file_open) {
@@ -808,6 +808,12 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags, 
        goto unlink_and_fail;

    }



    if (flags & BDRV_O_RDWR) {

        flags |= BDRV_O_ALLOW_RDWR;

    }



    bs->keep_read_only = !(flags & BDRV_O_ALLOW_RDWR);



    /* Open the image */

    ret = bdrv_open_common(bs, filename, flags, drv);

    if (ret < 0) {
@@ -837,12 +843,6 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags, 
            bdrv_close(bs);

            return ret;

        }

        if (bs->is_temporary) {

            bs->backing_hd->keep_read_only = !(flags & BDRV_O_RDWR);

        } else {

            /* base image inherits from "parent" */

            bs->backing_hd->keep_read_only = bs->keep_read_only;

        }

    }



    if (!bdrv_key_required(bs)) {

block.h

+1 −0
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ typedef struct BlockDevOps { 
#define BDRV_O_COPY_ON_READ 0x0400 /* copy read backing sectors into image */

#define BDRV_O_INCOMING    0x0800  /* consistency hint for incoming migration */

#define BDRV_O_CHECK       0x1000  /* open solely for consistency check */

#define BDRV_O_ALLOW_RDWR  0x2000  /* allow reopen to change from r/o to r/w */



#define BDRV_O_CACHE_MASK  (BDRV_O_NOCACHE | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH)