| Message ID | 1269796032-9166-2-git-send-email-ozaki.ryota@gmail.com |
|---|---|
| State | New |
| Headers | show |
Am 28.03.2010 19:07, schrieb Ryota Ozaki: > This patch allows to operate on nbd device file > without write permission for the file if read-only > option is specified. > > Signed-off-by: Ryota Ozaki <ozaki.ryota@gmail.com> The help for -r should be changed, too. Currently it says: -r, --read-only export read-only > --- > qemu-nbd.c | 10 +++++----- > 1 files changed, 5 insertions(+), 5 deletions(-) > > diff --git a/qemu-nbd.c b/qemu-nbd.c > index 00b8896..7ef409f 100644 > --- a/qemu-nbd.c > +++ b/qemu-nbd.c > @@ -162,7 +162,7 @@ static int find_partition(BlockDriverState *bs, int partition, > return -1; > } > > -static void show_parts(const char *device) > +static void show_parts(const char *device, bool readonly) > { > if (fork() == 0) { > int nbd; > @@ -172,7 +172,7 @@ static void show_parts(const char *device) > * but remember to load the module with max_part != 0 : > * modprobe nbd max_part=63 > */ > - nbd = open(device, O_RDWR); > + nbd = open(device, readonly ? O_RDONLY : O_RDWR); > if (nbd != -1) { > close(nbd); > } Can't we always use O_RDONLY here? Assuming that this is enough to trigger a partition table update, I haven't tested it. But if it's not enough, wouldn't be enough for readonly either. Kevin
On Mon, Mar 29, 2010 at 7:54 PM, Kevin Wolf <kwolf@redhat.com> wrote: > Am 28.03.2010 19:07, schrieb Ryota Ozaki: >> This patch allows to operate on nbd device file >> without write permission for the file if read-only >> option is specified. >> >> Signed-off-by: Ryota Ozaki <ozaki.ryota@gmail.com> > > The help for -r should be changed, too. Currently it says: > > -r, --read-only export read-only Indeed. > >> --- >> qemu-nbd.c | 10 +++++----- >> 1 files changed, 5 insertions(+), 5 deletions(-) >> >> diff --git a/qemu-nbd.c b/qemu-nbd.c >> index 00b8896..7ef409f 100644 >> --- a/qemu-nbd.c >> +++ b/qemu-nbd.c >> @@ -162,7 +162,7 @@ static int find_partition(BlockDriverState *bs, int partition, >> return -1; >> } >> >> -static void show_parts(const char *device) >> +static void show_parts(const char *device, bool readonly) >> { >> if (fork() == 0) { >> int nbd; >> @@ -172,7 +172,7 @@ static void show_parts(const char *device) >> * but remember to load the module with max_part != 0 : >> * modprobe nbd max_part=63 >> */ >> - nbd = open(device, O_RDWR); >> + nbd = open(device, readonly ? O_RDONLY : O_RDWR); >> if (nbd != -1) { >> close(nbd); >> } > > Can't we always use O_RDONLY here? Assuming that this is enough to > trigger a partition table update, I haven't tested it. But if it's not > enough, wouldn't be enough for readonly either. You're right. It works always with O_RDONLY. So we can remove the condition expression. However, I will drop this patch because I found I misunderstood about nbd. The patch intended to be for non-root users, but it does not make sense because nbd requires CAP_SYS_ADMIN. So I hold it until I understand well and focus on the last patch at first. I'm sorry for messing up. Thanks, ozaki-r > > Kevin >
diff --git a/qemu-nbd.c b/qemu-nbd.c index 00b8896..7ef409f 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -162,7 +162,7 @@ static int find_partition(BlockDriverState *bs, int partition, return -1; } -static void show_parts(const char *device) +static void show_parts(const char *device, bool readonly) { if (fork() == 0) { int nbd; @@ -172,7 +172,7 @@ static void show_parts(const char *device) * but remember to load the module with max_part != 0 : * modprobe nbd max_part=63 */ - nbd = open(device, O_RDWR); + nbd = open(device, readonly ? O_RDONLY : O_RDWR); if (nbd != -1) { close(nbd); } @@ -322,7 +322,7 @@ int main(int argc, char **argv) } if (disconnect) { - fd = open(argv[optind], O_RDWR); + fd = open(argv[optind], readonly ? O_RDONLY : O_RDWR); if (fd == -1) { errx(EXIT_FAILURE, "Cannot open %s", argv[optind]); } @@ -392,7 +392,7 @@ int main(int argc, char **argv) } } while (sock == -1); - fd = open(device, O_RDWR); + fd = open(device, readonly ? O_RDONLY : O_RDWR); if (fd == -1) { ret = 1; goto out; @@ -415,7 +415,7 @@ int main(int argc, char **argv) /* update partition table */ - show_parts(device); + show_parts(device, readonly); nbd_client(fd, sock); close(fd);
This patch allows to operate on nbd device file without write permission for the file if read-only option is specified. Signed-off-by: Ryota Ozaki <ozaki.ryota@gmail.com> --- qemu-nbd.c | 10 +++++----- 1 files changed, 5 insertions(+), 5 deletions(-)