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: Jeff Cody <jc...@redhat.com> --- block.c | 16 +++++++--------- block.h | 1 + 2 files changed, 8 insertions(+), 9 deletions(-) diff --git a/block.c b/block.c index 470bdcc..e31b76f 100644 --- a/block.c +++ b/block.c @@ -655,7 +655,7 @@ static int bdrv_open_common(BlockDriverState *bs, const char *filename, * Clear flags that are internal to the block layer before opening the * image. */ - open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); + open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_ALLOW_RDWR); /* * Snapshots should be writable. @@ -664,8 +664,6 @@ 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); - /* Open the image, either directly or using a protocol */ if (drv->bdrv_file_open) { ret = drv->bdrv_file_open(bs, filename, open_flags); @@ -804,6 +802,12 @@ 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) { @@ -833,12 +837,6 @@ 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)) { diff --git a/block.h b/block.h index 2e2be11..4d919c2 100644 --- a/block.h +++ b/block.h @@ -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) -- 1.7.11.2