diff options
Diffstat (limited to 'block/dirty-bitmap.c')
| -rw-r--r-- | block/dirty-bitmap.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c index e46f72b346..c6d4acebfa 100644 --- a/block/dirty-bitmap.c +++ b/block/dirty-bitmap.c @@ -29,12 +29,20 @@ #include "block/blockjob.h" /** - * A BdrvDirtyBitmap can be in three possible states: - * (1) successor is NULL and disabled is false: full r/w mode - * (2) successor is NULL and disabled is true: read only mode ("disabled") - * (3) successor is set: frozen mode. - * A frozen bitmap cannot be renamed, deleted, anonymized, cleared, set, - * or enabled. A frozen bitmap can only abdicate() or reclaim(). + * A BdrvDirtyBitmap can be in four possible user-visible states: + * (1) Active: successor is NULL, and disabled is false: full r/w mode + * (2) Disabled: successor is NULL, and disabled is true: qualified r/w mode, + * guest writes are dropped, but monitor writes are possible, + * through commands like merge and clear. + * (3) Frozen: successor is not NULL. + * A frozen bitmap cannot be renamed, deleted, cleared, set, + * enabled, merged to, etc. A frozen bitmap can only abdicate() + * or reclaim(). + * In this state, the anonymous successor bitmap may be either + * Active and recording writes from the guest (e.g. backup jobs), + * but it can be Disabled and not recording writes. + * (4) Locked: Whether Active or Disabled, the user cannot modify this bitmap + * in any way from the monitor. */ struct BdrvDirtyBitmap { QemuMutex *mutex; |