80 lines
3.0 KiB
Diff
80 lines
3.0 KiB
Diff
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From: Max Reitz <mreitz@redhat.com>
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Date: Fri, 8 Nov 2019 13:34:51 +0100
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Subject: block: Add bdrv_qapi_perm_to_blk_perm()
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Git-commit: 7b1d9c4df0603fbc526226a9c5ef91118aa6c957
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We need some way to correlate QAPI BlockPermission values with
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BLK_PERM_* flags. We could:
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(1) have the same order in the QAPI definition as the the BLK_PERM_*
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flags are in LSb-first order. However, then there is no guarantee
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that they actually match (e.g. when someone modifies the QAPI schema
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without thinking of the BLK_PERM_* definitions).
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We could add static assertions, but these would break what’s good
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about this solution, namely its simplicity.
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(2) define the BLK_PERM_* flags based on the BlockPermission values.
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But this way whenever someone were to modify the QAPI order
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(perfectly sensible in theory), the BLK_PERM_* values would change.
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Because these values are used for file locking, this might break
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file locking between different qemu versions.
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Therefore, go the slightly more cumbersome way: Add a function to
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translate from the QAPI constants to the BLK_PERM_* flags.
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Signed-off-by: Max Reitz <mreitz@redhat.com>
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Message-id: 20191108123455.39445-2-mreitz@redhat.com
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Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
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Signed-off-by: Max Reitz <mreitz@redhat.com>
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Signed-off-by: Bruce Rogers <brogers@suse.com>
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---
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block.c | 18 ++++++++++++++++++
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include/block/block.h | 1 +
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2 files changed, 19 insertions(+)
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diff --git a/block.c b/block.c
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index 2e5e8b639a88d430e52ef40973c7..2cc16f99b352623272491c1cf254 100644
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--- a/block.c
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+++ b/block.c
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@@ -2227,6 +2227,24 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
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*nshared = shared;
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}
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+uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm)
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+{
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+ static const uint64_t permissions[] = {
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+ [BLOCK_PERMISSION_CONSISTENT_READ] = BLK_PERM_CONSISTENT_READ,
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+ [BLOCK_PERMISSION_WRITE] = BLK_PERM_WRITE,
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+ [BLOCK_PERMISSION_WRITE_UNCHANGED] = BLK_PERM_WRITE_UNCHANGED,
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+ [BLOCK_PERMISSION_RESIZE] = BLK_PERM_RESIZE,
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+ [BLOCK_PERMISSION_GRAPH_MOD] = BLK_PERM_GRAPH_MOD,
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+ };
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+
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+ QEMU_BUILD_BUG_ON(ARRAY_SIZE(permissions) != BLOCK_PERMISSION__MAX);
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+ QEMU_BUILD_BUG_ON(1UL << ARRAY_SIZE(permissions) != BLK_PERM_ALL + 1);
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+
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+ assert(qapi_perm < BLOCK_PERMISSION__MAX);
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+
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+ return permissions[qapi_perm];
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+}
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+
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static void bdrv_replace_child_noperm(BdrvChild *child,
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BlockDriverState *new_bs)
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{
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diff --git a/include/block/block.h b/include/block/block.h
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index 1df9848e7436eec47e6251118a2f..e9dcfef7fa463e7655b4ec4a0d7c 100644
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--- a/include/block/block.h
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+++ b/include/block/block.h
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@@ -280,6 +280,7 @@ enum {
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};
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char *bdrv_perm_names(uint64_t perm);
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+uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm);
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/* disk I/O throttling */
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void bdrv_init(void);
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