| Message ID | 431ff7f85fb9c83b5300360273322e6a0c76aee2.1346352124.git.jcody@redhat.com |
|---|---|
| State | New |
| Headers | show |
Am 30.08.2012 20:47, schrieb Jeff Cody: > 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 <jcody@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); Do we still need bs->keep_read_only or is it duplicated in bs->open_flags now? We can convert all users in a follow-up patch. Kevin
On 09/05/2012 08:47 AM, Kevin Wolf wrote: > Am 30.08.2012 20:47, schrieb Jeff Cody: >> 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 <jcody@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); > > Do we still need bs->keep_read_only or is it duplicated in > bs->open_flags now? We can convert all users in a follow-up patch. > I think we can ditch keep_read_only, and just use BDRV_O_ALLOW_RDWR. The only other user of keep_read_only is the original bdrv_commit(), in block.c. And, the natural way to convert that function would be to have it use bdrv_reopen(), to change from r/o->r/w.
Am 05.09.2012 15:08, schrieb Jeff Cody: > On 09/05/2012 08:47 AM, Kevin Wolf wrote: >> Am 30.08.2012 20:47, schrieb Jeff Cody: >>> 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 <jcody@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); >> >> Do we still need bs->keep_read_only or is it duplicated in >> bs->open_flags now? We can convert all users in a follow-up patch. >> > > I think we can ditch keep_read_only, and just use BDRV_O_ALLOW_RDWR. The > only other user of keep_read_only is the original bdrv_commit(), in > block.c. And, the natural way to convert that function would be to have > it use bdrv_reopen(), to change from r/o->r/w. Ah, yes, makes sense. So just using it in patch 2 and then converting bdrv_commit() should be enough. Kevin
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)
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 <jcody@redhat.com> --- block.c | 16 +++++++--------- block.h | 1 + 2 files changed, 8 insertions(+), 9 deletions(-)