Re: [Libguestfs] [RFC libnbd PATCH] info: Add support for new qemu:joint-allocation

Qemu is adding qemu:joint-allocation as a single context combining the two bits of base:allocation and a compression of qemu:allocation-depth into two bits [1]. Decoding the bits makes it easier for humans to see the result of that context. [1] https://lists.gnu.org/archive/html/qemu-devel/2021-06/msg02446.html --- Obviously, this libnbd patch should only go in if the qemu RFC is accepted favorably. With this patch applied, the example listed in my qemu patch 2/2 commit message [2] becomes $ ~/libnbd/run nbdinfo --map=qemu:joint-allocation nbd://localhost 0 65536 3 hole,zero,unallocated 65536 65536 4 allocated,local 131072 65536 7 hole,zero,local 196608 65536 3 hole,zero,unallocated [2] https://lists.gnu.org/archive/html/qemu-devel/2021-06/msg02448.html For what it's worth, you can also play with the qemu+libnbd patches at: https://repo.or.cz/qemu/ericb.git/ master https://repo.or.cz/libnbd/ericb.git/ master (I sometimes rewind those branches, but they'll be stable for at least a few days after this email) info/map.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/info/map.c b/info/map.c index ae6d4fe..21e8657 100644 --- a/info/map.c +++ b/info/map.c @@ -226,6 +226,27 @@ extent_description (const char *metacontext, uint32_t type) return ret; } } + else if (strcmp (metacontext, "qemu:joint-allocation") == 0) { + /* Combo of base:allocation and stripped-down qemu:allocation-depth */ + const char *base, *depth; + switch (type & 3) { + case 0: base = "allocated"; break; + case 1: base = "hole"; break; + case 2: base = "zero"; break; + case 3: base = "hole,zero"; break; + } + switch (type & 0xc) { + case 0: depth = "unallocated"; break;

+ case 4: depth = "local"; break; + case 8: depth = "backing"; break; + case 12: depth = "<unexpected depth>"; break;

+ } + if (asprintf (&ret, "%s,%s", base, depth) == -1) { + perror ("asprintf"); + exit (EXIT_FAILURE); + } + return ret; + } return NULL; /* Don't know - description field will be omitted. */ } -- 2.31.1