From patchwork Wed Oct 17 16:00:23 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [RFC, V2, 14/20] qcow2: Extract qcow2_add_feature and qcow2_remove_feature. X-Patchwork-Submitter: =?utf-8?q?Beno=C3=AEt_Canet?= X-Patchwork-Id: 192105 Message-Id: <1350489629-1838-15-git-send-email-benoit@irqsave.net> To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, =?UTF-8?q?Beno=C3=AEt=20Canet?= , stefanha@redhat.com Date: Wed, 17 Oct 2012 18:00:23 +0200 From: =?UTF-8?q?Beno=C3=AEt=20Canet?= List-Id: These functions will be use to mark that deduplication is activatedi on an image. --- block/qcow2.c | 40 +++++++++++++++++++++++++++------------- block/qcow2.h | 4 ++-- 2 files changed, 29 insertions(+), 15 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index 18cb85d..b11b6a7 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -235,13 +235,14 @@ static void report_unsupported_feature(BlockDriverState *bs, } /* - * Sets the dirty bit and flushes afterwards if necessary. + * Sets the an incompatible feature bit and flushes afterwards if necessary. * * The incompatible_features bit is only set if the image file header was * updated successfully. Therefore it is not required to check the return * value of this function. */ -static int qcow2_mark_dirty(BlockDriverState *bs) +static int qcow2_add_feature(BlockDriverState *bs, + QCow2IncompatibleFeature feature) { BDRVQcowState *s = bs->opaque; uint64_t val; @@ -249,11 +250,11 @@ static int qcow2_mark_dirty(BlockDriverState *bs) assert(s->qcow_version >= 3); - if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { - return 0; /* already dirty */ + if (s->incompatible_features & feature) { + return 0; /* already added */ } - val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); + val = cpu_to_be64(s->incompatible_features | feature); ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features), &val, sizeof(val)); if (ret < 0) { @@ -264,32 +265,45 @@ static int qcow2_mark_dirty(BlockDriverState *bs) return ret; } - /* Only treat image as dirty if the header was updated successfully */ - s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; + /* Only treat image as having the feature if the header was updated + * successfully + */ + s->incompatible_features |= feature; return 0; } +static int qcow2_mark_dirty(BlockDriverState *bs) +{ + return qcow2_add_feature(bs, QCOW2_INCOMPAT_DIRTY); +} + /* - * Clears the dirty bit and flushes before if necessary. Only call this - * function when there are no pending requests, it does not guard against - * concurrent requests dirtying the image. + * Clears an incompatible feature bit and flushes before if necessary. + * Only call this function when there are no pending requests, it does not + * guard against concurrent requests adding a feature to the image. */ -static int qcow2_mark_clean(BlockDriverState *bs) +static int qcow2_remove_feature(BlockDriverState *bs, + QCow2IncompatibleFeature feature) { BDRVQcowState *s = bs->opaque; - if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { + if (s->incompatible_features & feature) { int ret = bdrv_flush(bs); if (ret < 0) { return ret; } - s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; + s->incompatible_features &= ~feature; return qcow2_update_header(bs); } return 0; } +static int qcow2_mark_clean(BlockDriverState *bs) +{ + return qcow2_remove_feature(bs, QCOW2_INCOMPAT_DIRTY); +} + static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result, BdrvCheckMode fix) { diff --git a/block/qcow2.h b/block/qcow2.h index ba900e0..5ecea94 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -125,14 +125,14 @@ enum { }; /* Incompatible feature bits */ -enum { +typedef enum { QCOW2_INCOMPAT_DIRTY_BITNR = 0, QCOW2_INCOMPAT_DIRTY = 1 << QCOW2_INCOMPAT_DIRTY_BITNR, QCOW2_INCOMPAT_DEDUP_BITNR = 1, QCOW2_INCOMPAT_DEDUP = 1 << QCOW2_INCOMPAT_DEDUP_BITNR, QCOW2_INCOMPAT_MASK = QCOW2_INCOMPAT_DIRTY | QCOW2_INCOMPAT_DEDUP, -}; +} QCow2IncompatibleFeature; /* Compatible feature bits */ enum {