From bcbf10c15f43cfc079622c25ef282688965a7128 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 13 Nov 2012 10:34:17 +0100 Subject: [PATCH] nbd: fixes to read-only handling We do not need BLKROSET if the kernel supports setting flags. Also, always do BLKROSET even for a read-write export, otherwise the read-only state remains "sticky" after the invocation of "qemu-nbd -r". Signed-off-by: Paolo Bonzini (cherry picked from commit c8969eded252058e90e91f12f75f32aceae46ec9) Signed-off-by: Michael Roth --- nbd.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/nbd.c b/nbd.c index 206f75c..19f6cd8 100644 --- a/nbd.c +++ b/nbd.c @@ -399,24 +399,23 @@ int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize) return -serrno; } - if (flags & NBD_FLAG_READ_ONLY) { - int read_only = 1; - TRACE("Setting readonly attribute"); - - if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) { + if (ioctl(fd, NBD_SET_FLAGS, flags) < 0) { + if (errno == ENOTTY) { + int read_only = (flags & NBD_FLAG_READ_ONLY) != 0; + TRACE("Setting readonly attribute"); + + if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) { + int serrno = errno; + LOG("Failed setting read-only attribute"); + return -serrno; + } + } else { int serrno = errno; - LOG("Failed setting read-only attribute"); + LOG("Failed setting flags"); return -serrno; } } - if (ioctl(fd, NBD_SET_FLAGS, flags) < 0 - && errno != ENOTTY) { - int serrno = errno; - LOG("Failed setting flags"); - return -serrno; - } - TRACE("Negotiation ended"); return 0; -- 1.8.0.2